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Associate Professor Allan Jones

Biography

Allan is the director of the surgical and anatomical skills laboratory at UTS. His primary area of research is the application of X-ray micro-tomography to the study of anatomical structure.

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Associate Professor, School of Life Sciences
B. App. Sci, Grad Dip. Biomedical Engineering, Ph D
 

Conferences

Curthoys, I.S., Uzun-Coruhlu, H., Wong, C.C., Jones, A.S. & Bradshaw, A.P. 2009, 'The configuration and attachment of the utricular and saccular maculae to the temporal bone. New evidence from microtomography-CT studies of the membranous labyrinth.', Ann N Y Acad Sci, United States, pp. 13-18.
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High-resolution X-ray microtomography (micro-CT) was used to show the spatial configuration of the membranous labyrinth of the fixed guinea pig and human inner ear. Whole temporal bones were en bloc stained in 2% osmium tetroxide for 2 days or more to allow the osmium to attach to the membranes of the inner ear, and then scanned with a Skyscan 1172 micro-CT with highest resolution of 8 microns. The scans were segmented and reconstructed. The findings for guinea pigs and humans are similar. The saccular macula is closely attached to the curved medial wall of the temporal bone, but in both human and guinea pig the utricular macula is attached to the temporal bone only at the anterior region of the macula, and, as others have reported previously, much of the caudal area of the utricular macula is tenuously supported by a thin membrane, just above the dorsal margin of the stapes. This tenuous support may have important consequences for the sensing of forces by the utricular macula. Combining information from a dissected human horizontal canal with CT images allows an estimate of the orientation of the horizontal canal crista in human subjects, data which are necessary for treatment of benign paroyxsmal positional vertigo of the horizontal canal. The very high resolution achieved by micro-CT shows that reconstruction from inadequately sampled CT data produces images that are not anatomically correct, so that canal deformations and aplasias may appear to be present.
Tovey, E.R., Taylor, D.J.M., Graham, A.H., O'Meara, T.J., Lovborg, U., Jones, A. & Sporik, R. 2000, 'New immunodiagnostic system', Aerobiologia, pp. 113-118.
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We have developed a new immunodiagnostic system which measures personal allergen exposure and which can be used to identify allergens. Personal exposure is directly sampled using inertial impaction filters which fit just inside the nose and collect particles (mainly > 5 m) inhaled during normal respiration. These samplers provide both an index of personal exposure as well as being an inexpensive and portable sampling system. The particles are captured on adhesive tapes which are then laminated with a protein-binding membrane. The allergens eluting from the particles are bound by the membrane in the periphery of each particle. The system then uses either allergen-specific monoclonal antibodies or the subject's IgE as primary probes to immuno-label the 'halo' of allergen around individual allergen-containing particles. Such an assay is very sensitive and can detect a single particle carrying allergens. In addition, the system provides information on the size, shape and allergen content of the particles. Because the particles carrying allergens can be seen, high resolution video images of pollen grains and fungal spores can be subjected to a traditional morphological study or a range of feature extraction routines. This information can be compared to a database of some known allergenic pollen grains and fungal spores which we have also assembled to facilitate their identification. When using monoclonal antibodies as the probe, the system determines the amount of allergen the subject is exposed to and the characteristics of the particles (size, shape, etc). When using the subject's IgE as the probe, the system allows visualisation of the allergen sources that an individual is allergic to. The system may have clinical applications in quantifying personal exposure as well as identifying allergens and determining exposure to unsuspected allergens.

Journal articles

Lees, T., Nassif, N., Simpson, A., Shad-Kaneez, F., Martiniello-Wilks, R., Lin, Y., Jones, A., Qu, X. & Lal, S. 2017, 'Recent advances in molecular biomarkers for diabetes mellitus: a systematic review.', Biomarkers, pp. 1-13.
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CONTEXT: Diabetes is a growing global metabolic epidemic. Current research is focussing on exploring how the biological processes and clinical outcomes of diabetes are related and developing novel biomarkers to measure these relationships, as this can subsequently improve diagnostic, therapeutic and management capacity. OBJECTIVE: The objective of this study is to identify the most recent advances in molecular biomarkers of diabetes and directions that warrant further research. METHODS: Using a systematic search strategy, the MEDLINE, CINAHL and OVID MEDLINE databases were canvassed for articles that investigated molecular biomarkers for diabetes. Initial selections were made based on article title, whilst final inclusion was informed by a critical appraisal of the full text of each article. RESULTS: The systematic search returned 246 records, of which 113 were unique. Following screening, 29 records were included in the final review. Three main research strategies (the development of novel technologies, broad biomarker panels, and targeted approaches) identified a number of potential biomarkers for diabetes including miR-126, C-reactive protein, 2-aminoadipic acid and betatrophin. CONCLUSION: The most promising research avenue identified is the detection and quantification of micro RNA. Further, the utilisation of functionalised electrodes as a means to detect biomarker compounds also warrants attention.
Eross, E., Turk, T., Elekdag-Turk, S., Cakmak, F., Jones, A.S., Vegh, A., Papadopoulou, A.K. & Darendelilerh, M.A. 2015, 'Physical properties of root cementum: Part 25. Extent of root resorption after the application of light and heavy buccopalatal jiggling forces for 12 weeks: A microcomputed tomography study', AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS, vol. 147, no. 6, pp. 738-746.
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Parr, W.C.H., Chamoli, U., Jones, A., Walsh, W.R. & Wroe, S. 2013, 'Finite element micro-modelling of a human ankle bone reveals the importance of the trabecular network to mechanical performance: new methods for the generation and comparison of 3D models.', J Biomech, vol. 46, no. 1, pp. 200-205.
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Most modelling of whole bones does not incorporate trabecular geometry and treats bone as a solid non-porous structure. Some studies have modelled trabecular networks in isolation. One study has modelled the performance of whole human bones incorporating trabeculae, although this required considerable computer resources and purpose-written code. The difference between mechanical behaviour in models that incorporate trabecular geometry and non-porous models has not been explored. The ability to easily model trabecular networks may shed light on the mechanical consequences of bone loss in osteoporosis and remodelling after implant insertion. Here we present a Finite Element Analysis (FEA) of a human ankle bone that includes trabecular network geometry. We compare results from this model with results from non-porous models and introduce protocols achievable on desktop computers using widely available softwares. Our findings show that models including trabecular geometry are considerably stiffer than non-porous whole bone models wherein the non-cortical component has the same mass as the trabecular network, suggesting inclusion of trabecular geometry is desirable. We further present new methods for the construction and analysis of 3D models permitting: (1) construction of multi-property, non-porous models wherein cortical layer thickness can be manipulated; (2) maintenance of the same triangle network for the outer cortical bone surface in both 3D reconstruction and non-porous models allowing exact replication of load and restraint cases; and (3) creation of an internal landmark point grid allowing direct comparison between 3D FE Models (FEMs).
Wong, C.C., Curthoys, I.S., O'Leary, S.J. & Jones, A.S. 2013, 'Heavy metal staining, a comparative assessment of gadolinium chloride and osmium tetroxide for inner ear labyrinthine contrast enhancement using X-ray microtomography.', Acta Otolaryngol, vol. 133, no. 1, pp. 22-27.
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CONCLUSION: The use of both gadolinium chloride (GdCl(3)) and osmium tetroxide (OsO(4)) allowed for the visualization of the membranous labyrinth and other intralabyrinthine structures, at different intensities, as compared with the control sample. This initial comparison shows the advantages of GdCl(3) in radiological assessments and OsO(4) in more detailed anatomical studies and pathways of labyrinthine pathogenesis using X-ray microtomography (microCT). OBJECTIVE: To assess an improved OsO(4) staining protocol and compare the staining affinities against GdCl(3). METHODS: Guinea pig temporal bones were stained with either GdCl(3) (2% w/v) for 7 days or OsO(4) (2% w/v) for 3 days, and scanned in a microCT system. The post-scanned datasets were then assessed in a 3D rendering program. RESULTS: The enhanced soft tissue contrast as presented in the temporal bones stained with either GdCl(3) or OsO(4) allowed for the membranous labyrinth to be visualized throughout the whole specimen. GdCl(3)-stained specimens presented more defined contours of the bone profile in the radiographs, while OsO(4)-stained specimens provided more anatomical detail of individual intralabyrinthine structures, hence allowing spatial relationships to be visualized with ease in a 3D rendering context and 2D axial slice images.
Silthampitag, P., Klineberg, I., Austin, B. & Jones, A.S. 2012, 'Bone microarchitecture at oral implant sites in ectodermal dysplasia (ED): a comparison between males and females.', Clin Oral Implants Res, vol. 23, no. 11, pp. 1275-1282.
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OBJECTIVE: The aim of this study was to analyse the microarchitecture of bone in association with implant placement in young ectodermal dysplasia (ED) patients. The general hypothesis was that the structural and morphological features of bone microarchitecture are different between males and females, which may influence clinical outcomes. MATERIALS AND METHODS: The bone harvesting is not additionally invasive, as the procedure was made at the time and site of implant placement. Twenty one samples (8 female, 13 male) were harvested from nine ED participants whose age ranged between 14 and 21 years and specified by the site of harvesting. Micro-CT analysis at 5 µm resolution was conducted on each sample. Specialized CT analysis of the three-dimensional (3-D) bone microstructure was made to compare structural parameters. In addition, two bone samples (one male, one female) were sent to the University of Michigan and analysed at 9 µm resolution. RESULTS: No significant difference was found between male and female samples. Bone analysis of particular sites revealed that bone-specific surface (BS/BV) was found to be significantly higher in male than in female samples, whilst the mean values of 10 parameters, the grey scale value histograms and 3-D visualization showed that female samples had higher compact density than male samples. CONCLUSION: Microstructural analyses indicated that female ED bone was more compact and with greater trabecular connectedness than male bone. These features may enhance resistance to external force transfer of mastication compared with male bone. Further bone samples from other jaw bone areas will provide information on whether there are regional differences in jawbone quality and quantity, which may influence implant treatment outcomes, as well as follow-up analyses of treatment outcomes.
Evans, S.P., Parr, W.C.H., Clausen, P.D., Jones, A. & Wroe, S. 2012, 'Finite element analysis of a micromechanical model of bone and a new 3D approach to validation.', J Biomech, vol. 45, no. 15, pp. 2702-2705.
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Finite Element Analysis (FEA) is now widely used to analyse the mechanical behaviour of bone structures. Ideally, simulations are validated against experimental data. To date, validation of Finite Element Models (FEMs) has been 2 Dimensional (2D) only, being based on comparison with surface-mounted strain gauge readings. In this study we present a novel 3-Dimensional (3D) approach to validation that allows comparison of modelled with experimental results between any two points in 3D space throughout the structure, providing magnitude and direction data for comparison, internally and externally. Specifically, we validate a FEM of a rat tibia, including trabecular network geometry, using a material testing stage housed within a microCT scanner. We further apply novel landmark based morphometric approaches to more effectively compare modelled and experimental results. 542 landmark points on the cortical and trabecular bone surfaces of the model were selected and validated in 3D against experimental data. This approach may hold considerable potential in fields wherein a better understanding of the mechanical behaviour of trabecular networks is important, e.g., the studies of osteoporosis and trabecular loss after orthopaedic implant insertion.
Mukherjee, P., Uzun-Coruhlu, H., Wong, C.C., Curthoys, I.S., Jones, A.S. & Gibson, W.P.R. 2012, 'Assessment of intracochlear trauma caused by the insertion of a new straight research array.', Cochlear Implants Int, vol. 13, no. 3, pp. 156-162.
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OBJECTIVE: To assess the degree of intracochlear trauma using the Cochlear Straight Research Array (SRA). This electrode has recently been released by Cochlear on the CI422 implant. BACKGROUND: Electroacoustic stimulation (EAS) enables recipients to benefit from cochlear implantation while retaining their natural low-frequency hearing. A disadvantage of short EAS electrodes is that short electrodes provide limited low-frequency stimulation. Thus, loss of the residual hearing may require reimplantation with a longer electrode. In order to overcome this problem, the slim diameter SRA with increased length (20-25 mm) has been designed to provide a deeper, yet non-traumatic insertion. METHODS: Two insertion studies into temporal bones were undertaken. The first involved dissection of the cochlea to gain a view into the scala vestibuli and insertion of the SRA and control electrodes with a microactuator for a surgeon-independent yet controlled insertion. High-speed photography was used to record data. The second study involved a high-resolution X-ray microcomputed tomography (microCT) study to assess electrode placement and tissue preservation in surgeon-implanted bones. RESULTS: The SRA had a smooth insertion trajectory. The average angular insertion depth was 383° when inserted until resistance was encountered, and 355° if inserted to a predetermined mark for EAS use. In addition, microCT data showed that this caused no significant trauma or distortion of the basilar membrane up to 20 mms depth. CONCLUSION: Temporal bone studies show that the SRA appears to cause no intracochlear trauma if used as an EAS electrode up to 20 mm depth of insertion.
Aras, B., Cheng, L.L., Turk, T., Elekdag-Turk, S., Jones, A.S. & Darendeliler, M.A. 2012, 'Physical properties of root cementum: part 23. Effects of 2 or 3 weekly reactivated continuous or intermittent orthodontic forces on root resorption and tooth movement: a microcomputed tomography study.', Am J Orthod Dentofacial Orthop, vol. 141, no. 2, pp. e29-e37.
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INTRODUCTION: The force application period is a modifiable factor in root resorption. There is still ambiguity if the continuity of force application is advantageous in terms of root resorption and tooth movement. In this prospective randomized clinical trial, we compared the effects of 2 reactivation periods of controlled-intermittent and continuous forces on root resorption and tooth movement. METHODS: Thirty-two patients were randomly divided into 2 groups: 2 weekly and 3 weekly reactivations. A split-mouth setup was used for the intermittent and continuous force comparisons. The intermittent force was designed with a pause of 3 days before each reactivation of the springs. A buccally directed tipping force (150 g) was generated with 0.017 0.025-in Beta III Titanium cantilever springs (3M Unitek, Monrovia, Calif). After the extractions, surface analysis was performed with microcomputed tomography (model 1172; SkyScan, Aartselaar, Belgium) and specially designed software (CHull2D) for direct volumetric analysis. Buccal premolar movement was also measured on the images of the study casts. RESULTS: Continuous forces produced more resorption than intermittent forces on the total volumes in both groups. A significant difference was found for the 3-weekly group only (P <0.01) on the cervical-mesial (P <0.01) and cervical-buccal (P <0.05) compression regions. In the 2-weekly group, differences were evident in the middle-distal (P <0.05) and middle-lingual (P <0.05) tension regions. Continuous forces produced significantly more tooth movement than did the intermittent forces for both the 2-weekly (P <0.01) and the 3-weekly (P <0.001) regimens. Significant differences were not observed between the 2 intermittent force regimens regarding root resorption and tooth movement. CONCLUSIONS: Intermittent force causes less root resorption and tooth movement than continuous force. Root resorption decreases irrespective of the timing of reactivation, when a pause is given. On ...
Montenegro, V.C.J., Jones, A., Petocz, P., Gonzales, C. & Darendeliler, M.A. 2012, 'Physical properties of root cementum: Part 22. Root resorption after the application of light and heavy extrusive orthodontic forces: a microcomputed tomography study.', Am J Orthod Dentofacial Orthop, vol. 141, no. 1, pp. e1-e9.
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INTRODUCTION: Extrusive tooth movement has been overlooked in the literature on root resorption. The aims of this study were to quantify the effects of light and heavy controlled extrusive forces on root resorption and to localize the sites of prevalence in premolars. METHODS: Ten patients (7 girls, 3 boys) who required bilateral maxillary first premolar extractions as part of their orthodontic treatment participated in this study. The total sample consisted of 20 maxillary first premolars. Light (25 g) or heavy (225 g) forces were applied to the right or left first premolar for 28 days. After the experimental period, the teeth were extracted without root damage and analyzed with microcomputed tomography. Each specimen was studied in 3 dimensions, and specially designed software was used to measure the volume of each crater. Wilcoxon signed rank tests were used for the statistical analysis. RESULTS: There was a significant difference in the total root resorption caused by light and heavy forces (P&nbsp;= 0.037). The discrepancy between the light and heavy groups was not significant for the cervical, middle, and apical regions separately. Only the distal surfaces were significantly different between the light and heavy forces (P&nbsp;= 0.008). CONCLUSIONS: Greater root resorption was observed after heavy extrusive forces when compared with light forces. The distal surfaces of the tooth root were significantly more affected than other root surfaces and might be influenced by root morphology and initial angulation of the tooth. There was no significant difference in the cervical, middle, and apical thirds in relation to root resorption after light or heavy extrusive forces.
King, A.D., Turk, T., Colak, C., Elekdag-Turk, S., Jones, A.S., Petocz, P. & Darendeliler, M.A. 2011, 'Physical properties of root cementum: part 21. Extent of root resorption after the application of 2.5° and 15° tips for 4 weeks: a microcomputed tomography study.', Am J Orthod Dentofacial Orthop, vol. 140, no. 6, pp. e299-e305.
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INTRODUCTION: Microcomputed tomography offers a unique opportunity to accurately examine orthodontically induced inflammatory root resorption. The aims of this study were to quantify, in 3 dimensions, the amount of root resorption caused by placing heavy and light distal root tipping forces on premolars and to compare the prevalence of root resorption in different areas of the tooth. METHODS: Thirty maxillary first premolars from 15 patients who were to have these teeth extracted as part of their orthodontic treatment were selected for this study. Each tooth in the same patient was randomly chosen to have either a 2.5&deg; or a 15&deg; distal root tipping bend placed for 4 weeks. After the experimental period, the teeth were extracted according to a strict protocol to prevent damage to the root. They were then imaged by a microcomputed tomography scan x-ray system (SkyScan 1172, SkyScan, Aartselaar, Belgium) and analyzed by software designed for volumetric measurements. RESULTS: A significant difference was found in the amount of total root resorption between light and heavy forces (P&nbsp;= .021). The mean cube root volumes of the resorption craters in the 15&deg; tip-bend group were greater than in the 2.5&deg; tip-bend group. This significance was lost when the tooth was divided into vertical thirds, although a trend was still present. When the areas of expected compression in the periodontal ligament were compared with the areas of expected tension, significance was seen in the apical and cervical thirds only. CONCLUSIONS: Based on this experiment, one can conclude that a 15&deg; distal root tip bend causes more orthodontically induced inflammatory root resorption than a 2.5&deg; distal root tip bend. Furthermore, greater root resorption was found in areas under pressure when compared with areas under tension.
Ho, C., Tüurk, T., Elekdaü-Türk, S., Jones, A.S., Petocz, P., Cheng, L.L. & Darendeliler, M.A. 2011, 'Erratum: Physical properties of root cementum: Part 19. Comparison of the amounts of root resorption between the right and left first premolars after application of buccally directed heavy orthodontictipping forces (American Journal of Orthodontics and Dentofacial Orthopedics (2011) 140 (e49-52))', American Journal of Orthodontics and Dentofacial Orthopedics, vol. 140, no. 5, p. 602.
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Meier, A., Farrow, C., Harris, B.E., King, G.G. & Jones, A. 2011, 'Application of texture analysis to ventilation SPECT/CT data.', Comput Med Imaging Graph, vol. 35, no. 6, pp. 438-450.
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It is demonstrated that textural parameters calculated from functional pulmonary CT data have the potential to provide a robust and objective quantitative characterisation of inhomogeneity in lung function and classification of lung diseases in routine clinical applications. Clear recommendations are made for optimum data preparation and textural parameter selection. A new set of platform-independent software tools are presented that are implemented as plug-ins for ImageJ. The tools allow segmentation and subsequent histogram-based and grey-level co-occurrence matrix based analysis of the regions of interest. The work-flow is optimised for use in a clinical environment for the analysis of transverse Computed Tomography (CT) scans and lung ventilation scans based on SPECT. Consistency tests are made against other texture analysis plug-ins and simulated lung CT data. The same methods are then applied to patient data consisting of a healthy reference group and one patient group each who suffered from asthma, chronic obstructive pulmonary disease (COPD), and COPD plus lung cancer. The potential for disease classification based on computer analysis is evaluated.
Bartley, N., Türk, T., Colak, C., Elekda-Türk, S., Jones, A., Petocz, P. & Darendeliler, M.A. 2011, 'Physical properties of root cementum: Part 17. Root resorption after the application of 2.5° and 15° of buccal root torque for 4 weeks: a microcomputed tomography study.', Am J Orthod Dentofacial Orthop, vol. 139, no. 4, pp. e353-e360.
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INTRODUCTION: Root resorption is an undesirable consequence of orthodontic tooth movement. The severity is unpredictable, and, despite extensive research, the etiology remains unknown. Torque has been acknowledged as a risk factor for root resorption. The aims of the study were to evaluate and quantify the extent of root resorption after the application of 2.5&deg; and 15&deg; of buccal root torque for 4 weeks. METHODS: Fifteen patients requiring bilateral extraction of their maxillary first premolars for orthodontic treatment were recruited to the study. By using a standardized experimental protocol, the right and left premolars were randomly subjected to either 2.5&deg; or 15&deg; of buccal root torque. At the end of the 4-week experimental period, the premolars were extracted. A volumetric analysis of root resorption was performed by using microcomputed tomography and measured with specially designed software. RESULTS: Overall, the amounts of root resorption were comparable after the application of 2.5&deg; or 15&deg; of buccal root torque (P&nbsp;= 0.59). There was a significant difference between the 2 force levels only at the apical region (P&nbsp;= 0.034). More root resorption occurred in areas of compression than in areas of tension. The variables of age and sex were not statistically significant. CONCLUSIONS: Root resorption was evident after 4 weeks of buccal root torque application. More root resorption was seen at the apical region than at the middle and cervical regions. Higher magnitudes of torque might cause more root resorption, particularly in the apical region. As shown in previous studies, the etiology of root resorption is multi-factorial and cannot be explained by mechanical factors alone.
Oh, C., Türk, T., Elekda-Türk, S., Jones, A.S., Petocz, P., Cheng, L.L. & Darendeliler, M.A. 2011, 'Physical properties of root cementum: Part 19. Comparison of the amounts of root resorption between the right and left first premolars after application of buccally directed heavy orthodontic tipping forces.', Am J Orthod Dentofacial Orthop, vol. 140, no. 1, pp. e49-e52.
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INTRODUCTION: Previous studies have used the right and left sides of the same jaw to compare different force levels, types of movement, and durations of forces. However, the amounts of root resorption have not been compared between the right and left sides after applying the same amount of force. The aims of the study were to quantitatively compare the volumes of the root resorption lacunae between the right and left first premolars to determine whether 1 side can serve as a control to the other and to compare the volumes of root resorption lacunae of the first premolars between the maxilla and the mandible. METHODS: Forty-four first premolars, orthodontically indicated for extraction from 11 patients (left and right maxillary and mandibular first premolars from each) were moved buccally by using beta-titanium-molybdenum alloy 0.017 0.025-in cantilever springs with continuous heavy (225 g) force. After the experimental period, the teeth were extracted under a strict protocol to prevent root cementum damage and then analyzed by using a microcomputed tomography scan x-ray system (1172; SkyScan, Aartselaar, Belgium) and specially designed software (Convex Hull 2D, University of Sydney, Sydney, Australia) for direct volumetric measurements. RESULTS: There were no statistically significant differences in the mean cube root volumes of root resorption craters between the right and left sides (P&nbsp;= 0.18) or between the maxillary and mandibular jaws (P&nbsp;= 0.10). There was also no statistical significance for the interception (P&nbsp;= 0.41), which indicated that the jaw and the side had independent effects. CONCLUSIONS: The amount of root resorption on the left and right sides of the jaw were similar in both the maxilla and the mandible. Therefore, for future root resorption studies, it is justifiable to use the split-mouth technique so that teeth from 1 side of the jaw can serve as the controls.
Silthampitag, P., Klineberg, I., Jones, A.S., Austin, B., Zee, K.Y., Wallace, C., Scholz, S., Naim, A. & Zoud, K. 2011, 'Ultramicroscopy of bone at oral implant sites: a comparison of ED and control patients. Part 1-defining the protocol.', Int J Prosthodont, vol. 24, no. 2, pp. 147-154.
PURPOSE: The aim of this study was to develop a protocol to analyze the microstructure of mandibular and maxillary bone in association with implant placement in ectodermal dysplasia (ED) and anodontia conditions compared to patients not suffering from such conditions. MATERIALS AND METHODS: This study was not additionally invasive, since the bone harvesting was completed at the time and site of implant placement. Bone samples were allocated into two groups (ED and control patients) and specified by the site of bone harvesting. Microcomputed tomography (micro-CT) analysis at 5-m resolution was conducted on each bone sample. Computer analysis applying specialized CT analysis and software allowed evaluation of the three-dimensional microstructure of alveolar and basal bone samples for comparison of structural parameters. RESULTS: Ten bone samples (five alveolar and five basal) were harvested. Preliminary data confirmed the structural features and significant differences between alveolar and basal bone. Basal bone had greater absolute and percent bone volume, greater bone surface, and a lower trabecular bone pattern factor than alveolar bone. CONCLUSION: Preliminary data were derived from bone harvested from both the maxilla and mandible of control patients, while bone samples from ED patients were harvested from only the anterior mandible. Further bone samples will provide more data on whether broader areas of bone harvesting, age, or sex affect the quality and quantity of the bone and influence implant treatment outcomes.
Wu, A.T.J., Turk, T., Colak, C., Elekda-Turk, S., Jones, A.S., Petocz, P. & Darendeliler, M.A. 2011, 'Physical properties of root cementum: Part 18. The extent of root resorption after the application of light and heavy controlled rotational orthodontic forces for 4 weeks: a microcomputed tomography study.', Am J Orthod Dentofacial Orthop, vol. 139, no. 5, pp. e495-e503.
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INTRODUCTION: The aim of this prospective randomized clinical trial was to quantitatively measure and compare the locations, dimensions, and volume of root resorption craters in human premolars after the application of controlled light and heavy rotational orthodontic forces over a 28-day (4-week) period. METHODS: Fifteen patients requiring bilateral extraction of maxillary first premolars as part of their orthodontic treatment were recruited for this study. Each patient received a heavy (225 g) rotational force on 1 premolar and a light (25 g) rotational force on the contralateral premolar. Orthodontic rotational forces were applied over 28 days with buccal and palatal cantilever springs; 0.016-inch beta-titanium molybdenum alloys were used to apply the light force and 0.018-inch stainless steel was used for the heavy force. After the 28-day experimental period, the upper first premolars were extracted under stringent protocols to prevent root surface damage. The samples were then scanned using a microcomputed tomography (micro-CT) scan x-ray system (SkyScan 1072, Skyscan, Aartselaar, Belgium), and analyzed using convex hull algorithm (CHULL2D; University of Sydney, Sydney, Australia) software to obtain direct volumetric measurements. RESULTS: The mean volume of resorption craters was 0.42 in the light force group and 0.51 in the heavy force group (P = 0.013). When separated at the root level, the difference in volume of root resorption craters between the 2 groups was significantly different only at the midlevel (P = 0.001). Root resorption craters were consistently detected at the boundaries between the buccal and distal surfaces and the mesial and lingual surfaces. The result supports our hypothesis that positive areas develop significantly more root resorption craters at all 3 levels, as compared with minimal areas (paired t test <0.001). CONCLUSIONS: Heavy rotational forces caused more root resorption than light rotational forces and compression areas (bucc...
Paetyangkul, A., Türk, T., Elekda-Türk, S., Jones, A.S., Petocz, P., Cheng, L.L. & Darendeliler, M.A. 2011, 'Physical properties of root cementum: Part 16. Comparisons of root resorption and resorption craters after the application of light and heavy continuous and controlled orthodontic forces for 4, 8, and 12 weeks.', Am J Orthod Dentofacial Orthop, vol. 139, no. 3, pp. e279-e284.
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INTRODUCTION: Orthodontic force duration can affect the severity of root resorption. The aim of this clinical study was to investigate the amounts of root resorption volumetrically after the application of controlled light and heavy forces in the buccal direction for 4, 8, and 12 weeks. METHODS: The sample consisted of 54 maxillary first premolars in 36 patients (mean age, 14.9 years; 21 girls, 15 boys) who required first premolar extractions as part of their orthodontic treatment. The teeth were allocated into 3 groups that varied in the duration of force application: 4, 8, or 12 weeks. The right or left first premolars were randomly selected to receive 2 levels of forces. A light buccally directed orthodontic force of 25 g was applied to the experimental tooth on 1 side, while a heavy orthodontic force of 225 g was applied on the contralateral premolar. At the end of the experimental period, the teeth were extracted and scanned with the microcomputed-tomography x-ray system. Resorption crater analysis was performed with specially designed software for direct volumetric measurements. RESULTS: Significant differences in the extent of root resorption were found between 4, 8, and 12 weeks of force application (P <0.001), with substantially more severe resorption in the longer force duration groups. The light force produced significantly less root resorption than did the heavy force. CONCLUSIONS: After 4, 8, or 12 weeks of buccally directed orthodontic forces applied on the maxillary first premolars, the volumes of root resorption craters were found to be related to the duration and the magnitude of the forces.
Tsafnat, N., Amanat, N. & Jones, A.S. 2011, 'Analysis of coke under compressive loading: A combined approach using micro-computed tomography, finite element analysis, and empirical models of porous structures', Fuel, vol. 90, no. 1, pp. 384-388.
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The behaviour of coke, a brittle porous material, under compressive loads is a major factor in determining its quality. Coke samples were compressed using a test stage fitted inside a micro-computed tomography scanner. Three-dimensional images of the samples before and after compression were acquired. The 'before' images were used to create finite element (FE) models of the coke. The effective Young's modulus was found by calibrating the linear elastic model using experimental data. The incremental displacement recorded during the experiments was then applied to the FE models. Comparison of FE analysis results with the 'after' images show high stress concentrations in the areas that cracked during the experiments, as well as reduced stresses in inerts. Displacement plots show a layered crushing pattern similar to that observed experimentally. Empirical models of brittle porous structures were used to estimate the elastic collapse stress of the coke wall. Results indicate that it may be the elastic collapse stress, rather than porosity, which best predicts whether a particular blend of coke will fail in compression. &copy; 2010 Elsevier Ltd. All rights reserved.
Mukherjee, P., Uzun-Coruhlu, H., Curthoys, I.S., Jones, A.S., Bradshaw, A.P. & Pohl, D.V. 2011, 'Three-dimensional analysis of the vestibular end organs in relation to the stapes footplate and piston placement.', Otol Neurotol, vol. 32, no. 3, pp. 367-372.
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OBJECTIVE: Measurements of the proximity of the membranous labyrinth to the stapes footplate show considerable variation. Largely, such measurements have been from histologic sections of fixed temporal bones, which may be affected by shrinkage artifact and perspective distortion in the 2-dimensional plane. To overcome these problems, the present study undertook an analysis of the 3-dimensional (3D) architecture of the relationship of the stapes to the membranous labyrinth using high-resolution X-ray micro-computed tomography. METHODS: Eleven temporal bones were fixed with Karnovsky's fixative (known to minimize shrinkage), soaked in 2% osmium tetroxide, and scanned in a micro-computed tomography scanner. The otic capsule was intact to exclude sectioning artifact, and no alcohol was used to avoid tissue shrinkage. Measurements were taken in a vertical plane to provide distances from the utricle and saccule to the footplate, and 3D reconstruction of the spatial relationship of these structures was carried out. The relationship of these structures to a stapes piston also was studied. RESULTS: The safest area of piston placement was the central and inferior part of the footplate. This was safe up to 0.5 mm depth at all areas except posterosuperiorly where the utricular macula is, on average, only 0.61 mm away from the footplate. The angle of insertion of the piston also influences the end result. CONCLUSION: Two-dimensional information about vestibular end organ location should serve as a guideline only because the operative field is 3D, and the relationship of the piston to the vestibular labyrinth changes with the angle of placement.
Ellis, S.L., Grassinger, J., Jones, A., Borg, J., Camenisch, T., Haylock, D., Bertoncello, I. & Nilsson, S.K. 2011, 'The relationship between bone, hemopoietic stem cells, and vasculature.', Blood, vol. 118, no. 6, pp. 1516-1524.
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A large body of evidence suggests hemopoietic stem cells (HSCs) exist in an endosteal niche close to bone, whereas others suggest that the HSC niche is intimately associated with vasculature. In this study, we show that transplanted hemopoietic stem and progenitor cells (HSPCs) home preferentially to the trabecular-rich metaphysis of the femurs in nonablated mice at all time points from 15 minutes to 15 hours after transplantation. Within this region, they exist in an endosteal niche in close association with blood vessels. The preferential homing of HSPCs to the metaphysis occurs rapidly after transplantation, suggesting that blood vessels within this region may express a unique repertoire of endothelial adhesive molecules. One candidate is hyaluronan (HA), which is highly expressed on the blood vessel endothelium in the metaphysis. Analysis of the early stages of homing and the spatial dis-tribution of transplanted HSPCs at the single-cell level in mice devoid of Has3-synthesized HA, provides evidence for a previously undescribed role for HA expressed on endothelial cells in directing the homing of HSPCs to the metaphysis.
Manconi, F., Kable, E.P., Dwarte, D., Jones, A., Russell, P., Chullapram, T., Gange, P.V., Obeysekara, S., Thomas, G.A. & Fraser, I.S. 2011, 'Three dimensional microvascular measurements in human endometrium using optical slices from laser scanning confocal microscopy (LSCM).', Micron, vol. 42, no. 8, pp. 853-862.
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There is increasing interest in the structure of the microvascular environment in human endometrium because of the recognition of the complexity and functional importance of this tissue. Endometrial microcirculatory networks and their relationships have rarely been studied in three-dimensions. Longitudinal uterine slices containing endometrial tissue were carefully selected from women undergoing a hysterectomy. Formalin-fixed endometrial sections ( 50 m) representing the fundal and isthmic regions were immunofluorescently labeled with monoclonal antibody (CD34) to target the endothelium of microvessel and fluorescein isothiocyanate (FITC) labeled goat anti-mouse. Digital images were acquired using a Nikon Eclipse E800 microscope equipped with a Radiance 2000 confocal scanning laser attachment. ImarisBasic 4.1 visualization suite was utilized for qualitative interpretation. NeuronTracer 1.0 software was utilized to derive the length and numerical densities. There were significant changes across the phases of the menstrual cycle in functional and basal endometrial layers in vessel length density (LD(v)) and branch point density (ND(v)) within both fundal and isthmic regions of the uterus (P<0.001). There was also a significant effect of menstrual cycle phase on mean vessel segment length (SL(v)) within each region and within each of the layers (P<0.001). The capillary radial diffusion distance r(diff) was negatively correlated with LD(v). In general, within each of the menstrual cycle phases, LD(v), ND(v) were greater in the fundal than the isthmic regions while, in contrast, SL(v) was found to be greatest in the isthmic region. Utilization of immunofluorescence and laser scanning confocal microscopy has enabled us to demonstrate significant vascular changes in human endometrial layers illustrating that in general, within each of the menstrual cycle phases, vessel length and branch point densities were greater in the fundal than the isthmic regions, while vessel ...
Wang, Y., Lam, J., Zhang, B., Tomlins, P.E., Li, X., Alpar, O., Wertheim, D.F., Jones, A.S. & Coombes, A.G.A. 2010, 'Biomechanical Characterization of a Micro/Macroporous Polycaprolactone Tissue Integrating Vascular Graft', Cardiovascular Engineering and Technology, vol. 1, no. 3, pp. 202-215.
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The objective of the present study was to characterize the short-term biomechanical properties of cast micro/macroporous poly(caprolactone) (PCL) tubes intended for application as tissue integrating blood vessel substitutes. Micro/macroporous PCL vascular grafts (5. 5 mm internal diameter, 7.5 mm external diameter) with defined macropore structures were produced by rapidly cooling PCL solutions containing dispersed gelatin particles in dry ice, followed by solvent and gelatin extraction. A Bose-Enduratec BioDynamic chamber configured for cardiovascular applications was used to measure the diametrical stability (dilation) of tubular samples under hydrodynamic flow conditions at 37 &deg;C. Microporous PCL tubes withstood the hydrodynamic stresses induced by short, 2-min duration flow rates up to 1000 mL/min, which resulted in estimated internal pressures in excess of arterial pressure (80-130 mmHg). Micro/macroporous PCL tubes having a maximum macroporosity of 23% accommodated the hydrodynamic stresses generated by short duration, flow rates up to 1000 mL/min, which resulted in estimated internal pressures similar to venous pressure (30 mmHg). The dilation of microporous PCL tubes under short, (5 min) pulsatile flow conditions (1 Hz) increased from 10 to 100 m with increasing mean flow rate from 50 to 500 mL/min. Both microporous and macroporous tubes exhibited a burst strength higher than 900 mmHg under hydrostatic fluid pressure, which is in excess of arterial pressure (80-130 mmHg) by a factor of approximately 7. Quantitative analysis of the macropore structure was performed using micro-computed tomography for correlation with mechanical properties and cell growth rates. Mouse fibroblasts efficiently colonized the external surface of macroporous PCL materials over 8 days in cell culture and cell numbers were higher by a factor of two compared with microporous PCL. These findings demonstrate that micro/macroporous PCL tubes designed for vascular tissue engineering c...
Wang, Y., Wertheim, D.F., Jones, A.S. & Coombes, A.G.A. 2010, 'Micro-CT in drug delivery.', Eur J Pharm Biopharm, vol. 74, no. 1, pp. 41-49.
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Micro-computed tomography (micro-CT) has not to date been fully exploited in the area of controlled drug delivery despite its capability for providing detailed, 3-D images of morphology and the opportunity this presents for exploring the relationships between delivery device formulation, structure and performance. Micro-CT was used to characterize the internal structure of polycaprolactone (PCL) matrix-type devices incorporating soluble particulates (lactose Mw 342.30, gelatin Mw 20-25kDa) as models of hydrophilic bioactives or pore-forming excipients. Micro-CT images confirmed that the lactose and gelatin particles were uniformly dispersed throughout the PCL phase and that efficient delivery of 95-100% of each species in 9days involved transport from the matrix core. Quantitative analysis of micro-CT images provided values for matrix macroporosity, which were within 15% of the theoretical value and revealed uniform porosity throughout the samples. Total release of protein occurred in 9days (PBS, 37 degrees C) from matrices containing a high protein load (44%w/w) and was independent of particle size. Measurements of equivalent pore diameter and frequency distribution identified a large population of sub-40microm pores in each material, indicative of a high density of connecting channels between particles which facilitates protein transport through the matrices.
Wang, Y., Wertheim, D.F., Jones, A.S., Chang, H.-.I. & Coombes, A.G.A. 2010, 'Micro-CT analysis of matrix-type drug delivery devices and correlation with protein release behaviour.', J Pharm Sci, vol. 99, no. 6, pp. 2854-2862.
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A series of matrix-type drug delivery devices comprising a continuous phase of microporous poly(epsilon-caprolactone) (PCL) and a dispersed phase of protein particles (gelatin) with defined size ranges (45-90, 90-125 and 125-250 microm) were produced by rapidly cooling suspensions in dry ice followed by solvent extraction from the hardened material. High protein loadings (38-44%, w/w) were achieved and highly efficient protein release (90% of the initial load) was obtained over time periods of 3-11 days depending on particle loading and size range. The duration of protein release was extended from 3 to 11 days by reducing the protein load. Quantitative analysis of Micro-CT images identified a three to four times increase in the population of sub-40 microm pores in those matrices which gave rise to accelerated protein release in 24 h (40% rising to 80%) and reduced duration of protein release (11-3 days). Formation of a high density of channels and fissures (connects) between the particles is indicated, which facilitate fluid ingress and diffusion of solubilised protein molecules. Micro-CT analysis also confirmed the uniformity of particle distribution in the matrices and provided measurements of macroporosity within 5-30% of the theoretical value for materials displaying irregular shaped macropores larger than 90 microm. These findings demonstrate the utility of Micro-CT for optimising the formulation and performance of matrix-type delivery devices for macromolecular entities.
Cheng, L.L., Türk, T., Elekda-Türk, S., Jones, A.S., Yu, Y. & Darendeliler, M.A. 2010, 'Repair of root resorption 4 and 8 weeks after application of continuous light and heavy forces on premolars for 4 weeks: a histology study.', Am J Orthod Dentofacial Orthop, vol. 138, no. 6, pp. 727-734.
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INTRODUCTION: Repair of root resorption cavities has been studied under light microscopy, scanning electron microscopy, and transmission electron microscopy. The aim of this investigation was to demonstrate the use of microcomputed tomography (micro-CT) to assist in the identification of the region of interest for light microscopy preparation. This study also qualitatively illustrated the root resorption craters with 4 or 8 weeks of retention after 4 weeks of continuous light or heavy orthodontic force application. METHODS: Four patients who required bilateral extractions of maxillary first premolars as part of their orthodontic treatment were divided into 2 groups (groups I and II) of 2. The maxillary left and right first premolars were loaded with light (25 g) or heavy (225 g) orthodontic force for 4 weeks. After 4 or 8 weeks of retention, the maxillary first premolars were extracted. The extracted teeth were investigated with micro-CT. By using 3-dimensional images created by the micro-CT, the largest resorption craters on the buccal and lingual sides were identified. Parasagittal sections of these resorption craters were studied histologically under hematoxylin and eosin staining. RESULTS: The use of micro-CT improved the efficiency and accuracy of histologic techniques. Comparatively, less root resorption was repaired by new cementum after heavy orthodontic force application and short retention time. The reparative processes seemed to depend on time, with longer retention time yielding the most amount of repair. Reparative cementum was a mixture of acellular and cellular cementum. Reparative processes seemed to commence at the central part of the resorption cavity and expand to the periphery. CONCLUSIONS: Root resorption cavities have the potential to repair regardless of the orthodontic force magnitude. Correlative microscopy with micro-CT and conventional light microscopy adds a new dimension to current root resorption investigation techniques.
Soriano, C., Archer, M., Azar, D., Creaser, P., Delclòs, X., Godthelp, H., Hand, S., Jones, A., Nel, A., Néraudeau, D., Ortega-Blanco, J., Pérez-de la Fuente, R., Perrichot, V., Saupe, E., Kraemer, M.S. & Tafforeau, P. 2010, 'Synchrotron X-ray imaging of inclusions in amber', Comptes Rendus - Palevol, vol. 9, no. 6-7, pp. 361-368.
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Over the past six years, organic inclusions preserved in amber samples from outcrops worldwide have been discovered and imaged in 3D using propagation phase contrast based X-ray synchrotron imaging techniques at the European Synchrotron Radiation Facility (ESRF). A brief description of the techniques and protocols used for detecting and 3D non-destructive imaging of amber inclusions is provided. The latest results from the major amber projects in the ESRF are given, illustrating the increasing utility of the imaging capabilities of X-ray synchrotron phase contrast microtomography. &copy; 2010 Acad&eacute;mie des sciences.
Deane, S., Jones, A.S., Petocz, P. & Darendeliler, M.A. 2009, 'Physical properties of root cementum: part 12. The incidence of physiologic root resorption on unerupted third molars and its comparison with orthodontically treated premolars: a microcomputed-tomography study.', Am J Orthod Dentofacial Orthop, vol. 136, no. 2, pp. 148.e1-148.e9.
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UNLABELLED: INTRODUCTION Root resorption can occur as a physiologic or a pathologic process, and it is an unwanted side effect of orthodontic treatment. No baseline studies have assessed this phenomenon in the absence of force variables such as mastication, parafunction, and soft-tissue pressure. In this study, we investigated the incidence and quantitative value of root resorption on unerupted third molars with normal development using microcomputed tomography. METHODS: Nine unerupted, nonimpacted maxillary third molars were collected from 6 patients (ages, 19.47 plus /minus 1.89 years). The teeth were examined with microcomputed tomography and compared with teeth from other studies. (The other teeth had been treated with buccally directed light [25 g] or heavy [225 g] forces applied for 28 days, or light [25 g] or heavy [225 g] intrusion forces for 28 days.) RESULTS: Imaging and volumetric analyses showed resorption craters in many locations and with various magnitudes. Analysis of variance was completed by position (P = 0.04), surface (P = 0.07), height (P = 0.045), left or right side of the mouth (P = 0.85), and subject (P = 0.70). The midroot region on the mesial surfaces of the third molars, near the root structure of adjacent erupted second molars, had the greatest statistical significance. When compared with crater volumes of fully erupted first premolars, we found that the unerupted third molar sample had a slightly greater cube root volume per tooth than the erupted first premolars not subjected to orthodontic force and a similar cube root volume per tooth as did first premolars subjected to light (25 g) buccal and intrusive orthodontic forces. CONCLUSIONS: Root resorption as a consequence of orthodontic treatment might be added to a baseline level of root resorption. The elevated results suggest that resorption might occur as part of hard-tissue remodeling and turnover, eruption, or transmission of masticatory forces through the dentition to the alveol...
Cheng, L.L., Türk, T., Elekda-Türk, S., Jones, A.S., Petocz, P. & Darendeliler, M.A. 2009, 'Physical properties of root cementum: Part 13. Repair of root resorption 4 and 8 weeks after the application of continuous light and heavy forces for 4 weeks: a microcomputed-tomography study.', Am J Orthod Dentofacial Orthop, vol. 136, no. 3, pp. 320.e1-320.10.
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INTRODUCTION: The reparative process of root absorption begins in the periodontium when orthodontic force is discontinued or reduced below a certain level. Our aim was to evaluate cementum repair at 4 and 8 weeks of retention after 4 weeks of continuous light and heavy orthodontic forces. The effects of age, tooth movement, and fluoride exposure were also investigated. METHODS: Forty patients were recruited and divided into 4 groups of 10. The maxillary first premolars were loaded with either light (25 g) or heavy (225 g) orthodontic force. After 4 weeks of loading, the maxillary left first premolars were extracted as the positive control group, and the maxillary right first premolars were placed in retention for 4 or 8 more weeks before extraction; these were the experimental groups. The extracted teeth were studied with microcomputed tomography. To assess cementum repair, volumetric changes of the resorption craters were measured with specially designed computer software. Tooth movement was also measured on study casts taken before and after the extractions. RESULTS: Root resorption continued for 4 weeks after orthodontic force ceased. The resorptive activity was more pronounced from heavy forces. Passive retention after 4 weeks of light force had the least root resorption crater volume (cube root scale). The total amount of the cementum repaired did not depend on magnitude of orthodontic force or retention time within our parameters (P >0.05). This might indicate concurrence of resorption and repair during passive retention. Most repair seemed to occur after 4 weeks of passive retention following the 4 weeks of heavy forces. The volume of root resorption craters positively depended on tooth movement (P = 0.02) and negatively correlated with chronologic age (P <0.01). CONCLUSIONS: Although there was no significant difference in the amounts of repair between groups, root resorption continued for 4 weeks after orthodontic force stopped. Resorptive activity was mo...
Ballard, D.J., Jones, A.S., Petocz, P. & Darendeliler, M.A. 2009, 'Physical properties of root cementum: part 11. Continuous vs intermittent controlled orthodontic forces on root resorption. A microcomputed-tomography study.', Am J Orthod Dentofacial Orthop, vol. 136, no. 1, pp. 8.e1-8.e8.
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INTRODUCTION: There is still ambiguity about whether continuous or intermittent orthodontic forces produce more root resorption. This prospective randomized clinical trial was designed to compare root resorption with these 2 force application patterns. METHODS: The sample consisted of 16 maxillary first premolars from 8 patients who required bilateral extractions as part of their orthodontic treatment. In each subject, a fixed experimental appliance was placed on the maxillary teeth on each side, allowing a buccally directed force. The force was generated by a segmental wire of beta-titanium-molybdenum alloy. The first premolar on 1 side received a buccally directed continuous force, and the contralateral premolar received intermittent force. The initial force magnitude for both sides was 225 cN. After 14 days of initial continuous force, the intermittent force application was obtained with subsequently repeated periods until the end of the eighth week of a 3-day rest period followed by a 4-day force application period. Force levels were set to 225 cN at each patient visit. After the experimental period of 8 weeks, the teeth were extracted under a strict protocol to prevent root surface damage and analyzed with a microcomputed-tomography scan system, and specially designed software was used for direct volumetric measurements. RESULTS: Intermittent force produced less root resorption than continuous force (P <0.05). Analysis by position showed that the buccal-cervical region had significantly more root resorption than the other positions (P <0.001), corresponding to a region of compression generated by tipping. CONCLUSIONS: The application of intermittent orthodontic forces of 225 cN for 8 weeks (14 days of force application, 3 days of rest, then 4 days of force application repeated for 6 weeks) caused less root resorption than continuous forces of 225 cN for 8 weeks. Although it might not be clinically practical, compared with continuous forces, intermittent forc...
Sriram, D., Jones, A., Alatli-Burt, I. & Darendeliler, M.A. 2009, 'Effects of mechanical stimuli on adaptive remodeling of condylar cartilage.', J Dent Res, vol. 88, no. 5, pp. 466-470.
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Trabecular bone has been shown to be responsive to low-magnitude, high-frequency mechanical stimuli. This study aimed to assess the effects of these stimuli on condylar cartilage and its endochondral bone. Forty female 12-week-old C3H mice were divided into 3 groups: baseline control (killed at day 0), sham (killed at day 28 without exposure to mechanical stimuli), and experimental (killed following 28 days of exposure to mechanical stimuli). The experimental group was subjected to mechanical vibration of 30 Hz, for 20 minutes per day, 5 days per week, for 28 days. The specimens were analyzed by micro-computed tomography. The experimental group demonstrated a significant decrease in the volume of condylar cartilage and also a significant increase in bone histomorphometric parameters. The results suggest that the low-magnitude, high-frequency mechanical stimuli enhance adaptive remodeling of condylar cartilage, evidenced by the advent of endochondral bone replacing the hypertrophic cartilage.
Paetyangkul, A., Türk, T., Elekda-Türk, S., Jones, A.S., Petocz, P. & Darendeliler, M.A. 2009, 'Physical properties of root cementum: part 14. The amount of root resorption after force application for 12 weeks on maxillary and mandibular premolars: a microcomputed-tomography study.', Am J Orthod Dentofacial Orthop, vol. 136, no. 4, pp. 492.e1-492.e9.
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INTRODUCTION: Orthodontic force magnitude is a primary factor in root resorption. Quantitative studies of root resorption after force application for 4 and 8 weeks have been conducted. In this study, we investigated the root surface topography and the amount of root resorption after the application of controlled light and heavy forces in a buccal direction for 12 weeks. In addition, the amounts of root resorption when controlled light and heavy forces were applied to the maxillary and mandibular first premolars were quantified. METHODS: Forty maxillary and mandibular first premolars were collected from 10 orthodontic patients (age range, 12.7-18.2 years; mean, 14.3 years). A light buccally directed orthodontic force of 25 g was applied to the experimental tooth on 1 side, and a heavy orthodontic force of 225 g was applied on the contralateral premolar. After 12 weeks of force application, the experimental teeth were extracted and scanned with the microcomputed tomography x-ray system. Resorption craters were analyzed with specially designed software for direct volumetric measurements. The tooth movements produced by light and heavy forces were also measured. RESULTS: There was individual variation in all comparisons. The light force produced significantly less root resorption than did the heavy force. The maxillary first premolars were more likely to suffer from orthodontically induced inflammatory root resorption than the mandibular first premolars (P = 0.036). There was a significant difference between buccal and lingual surfaces (P = 0.003), with greater root resorption on the buccal surface. The distribution pattern of the resorption cavities was greatest in the buccal-cervical, buccal-middle, lingual-middle, and lingual-apical areas in both the light-force and heavy-force groups, corresponding with the pressure zones of tipping movement. The mean amount of tooth movement in the heavy-force group was almost twice as much as in the light-force group. CONCLUSIO...
Maddocks, A.R., Cassidy, D.J., Jones, A.S. & Harris, A.T. 2009, 'Synthesis of nanoporous silicon carbide via the preceramic polymer route', Materials Chemistry and Physics, vol. 113, no. 2-3, pp. 861-867.
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Nanoporous silicon carbide materials were prepared by the pyrolysis of the preceramic polymer, polycarbosilane (PCS), with and without the addition of an inert filler (nano- and micron-sized silicon carbide powders). Hydrosilylation crosslinking of PCS with divinylbenzene prior to pyrolysis appeared to have little influence on the development of micro- and mesoporosity. Maximum micropore volumes were 0.28 cm 3 g -1 for non-crosslinked PCS and 0.25, 0.33 and 0.32 cm 3 g -1 for PCS crosslinked with 2, 6 and 10 wt.% DVB respectively. Micropore volumes decreased under hydrothermal conditions to 0.03 cm 3 g -1 for non-crosslinked and 0 cm 3 g -1 for crosslinked PCS. Porosity was also lost at temperatures above 700 &deg;C. The addition of nano-sized SiC powders to PCS prior to pyrolysis maintained mesoporosity to temperatures of 1200 &deg;C, however, micron-sized SiC powders did not maintain porosity above 800 &deg;C. The modal pore size in pellets formed by compressing micron-sized powders with the preceramic polymer was 5 m compared to 30 nm when nano-sized powders were used. &copy; 2008 Elsevier B.V. All rights reserved.
Amanat, N., Tsafnat, N., Loo, B.C.E. & Jones, A.S. 2009, 'Metallurgical coke: An investigation into compression properties and microstructure using X-ray microtomography', Scripta Materialia, vol. 60, no. 2, pp. 92-95.
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The compression properties of coke were investigated at slow strain rates, using a traditional Instron materials tester. To further characterize the failure mechanism, X-ray microtomography was used to visually examine the internal deformation of the coke during compression. It was found that the coke samples failed in a progressive layering manner, and were still able to maintain load for the duration of the compression test. Crown Copyright &copy; 2008.
Tsafnat, N., Tsafnat, G. & Jones, A.S. 2009, 'Automated mineralogy using finite element analysis and X-ray microtomography', Minerals Engineering, vol. 22, no. 2, pp. 149-155.
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The three-dimensional microstructure of minerals and materials can be visualised in a non-destructive manner using X-ray microtomography. The digitised nature of the tomographic image allows us to generate finite element models which precisely detail the material's microstructure. With a high degree of automation, high resolution models can be created quickly and with little user interaction. The geometry is taken from the microtomographic data, and loads and boundary conditions are applied to the model to simulate various conditions. The finite element analysis results show the deformation and stress distribution in the material. The technique allows us to study the relationship between microstructure and bulk properties of porous minerals, to characterise them in terms of their strength and stiffness, and to simulate their behaviour under known loading conditions. In this paper we present an application of micro-finite element analysis in the study of porous minerals. Micro-finite element analysis can be used to study the behaviour of a variety of minerals, and is especially useful when applied to materials that have a distinct microstructure that affects their bulk properties. &copy; 2008 Elsevier Ltd. All rights reserved.
Young, P.M., Nguyen, K., Jones, A.S. & Traini, D. 2008, 'Microstructural Analysis of Porous Composite Materials: Dynamic Imaging of Drug Dissolution and Diffusion Through Porous Matrices', AAPS Journal, vol. 10, no. 4, pp. 560-564.
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Barbagallo, L.J., Jones, A.S., Petocz, P. & Darendeliler, M.A. 2008, 'Physical properties of root cementum: Part 10. Comparison of the effects of invisible removable thermoplastic appliances with light and heavy orthodontic forces on premolar cementum. A microcomputed-tomography study.', Am J Orthod Dentofacial Orthop, vol. 133, no. 2, pp. 218-227.
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INTRODUCTION: Orthodontic treatment with clear sequential removable thermoplastic appliances (TAs) is gaining popularity as an alternative to treatment with fixed appliances. The amount of orthodontically induced inflammatory root resorption generated by such appliances has not been investigated. In this prospective randomized clinical trial, we used x-ray microtomography to quantify resorption generated by treatment with ClearSmile appliances (ClearSmile, Woollongong, Australia) and compared the effects with those of heavy and light conventional orthodontic forces and no force. METHODS: The sample consisted of 54 maxillary first premolars in 27 patients who required bilateral extractions as part of their planned orthodontic treatment. The subjects were randomly assigned to 3 groups, each with 9 subjects. A split-mouth design was used, and forces were applied to the first premolars. In group 1, TAs were used to move teeth on 1 side in a buccal direction at a rate of 0.5 mm every 2 weeks (TA movement); the contralateral teeth were not moved and served at controls. In group 2, TA movement was used on 1 side. A buccal force of 225 g from a beta-titanium alloy cantilever spring (heavy force) was used on the contralateral side. In group 3, TA movement was used on 1 side. A buccal force of 25 g from a cantilever spring (light force) was used on the contralateral side. The treatment duration was 8 weeks (56 days +/- 1 day). The TAs were changed every 14 days, and each patient used 4 appliances. The springs were not reactivated. At the end of the study period, the teeth were extracted according to a strict protocol to prevent root damage. Resorption was measured with an x-ray microtomograph (1072, SkyScan, Aartselaar, Belgium). Software analysis determined quantity, location, and distribution of root resorption craters. RESULTS: The control teeth had the least amount of resorption. The light-force teeth had approximately 5 times more resorption than the control teeth (P ...
Barbagallo, L.J., Shen, G., Jones, A.S., Swain, M.V., Petocz, P. & Darendeliler, M.A. 2008, 'A novel pressure film approach for determining the force imparted by clear removable thermoplastic appliances.', Ann Biomed Eng, vol. 36, no. 2, pp. 335-341.
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The force imparted by removable thermoplastic appliances (RTA) onto teeth has not been investigated in the past. This investigation was designed to explore a novel methodology to measure the magnitude and identify the pattern of this force. Eight patients with moderate malocclusion were selected. In each patient, the palatally mal-positioned upper first premolar was corrected by wearing a series of four ClearSmile RTA over a duration of 8 weeks. When constructing RTA, the ClearSmile Company was advised that the amount of movement to be programmed into each appliance was 0.5 mm. The Pressurex film was used to measure the pressure generated by ClearSmile RTA against the palatal surface of the upper first premolar for buccal tipping movement. Three measurements were conducted respectively upon the issue and retrieval of each appliance (after 2 weeks of wear), resulting in 24 pressure measurements for each patient. Digital imaging and spectrophotometry analysis were employed to quantify the stain intensity mounted by the pressure on the films. The irrelevant forces were subtracted out to allow an assessment of the force purely acting to buccally repositioning the tooth. The results revealed that (1) the mean force magnitude over 2 weeks of RTA wear was 1.12 N (SE = 0.72 N); (2) the higher force magnitude of 5.12 N (SE = 0.80 N) seen at the issue of the appliance declined drastically to -2.67 N at the time of retrieval. These findings suggest that ClearSmile RTA exerts a high level of force against the tooth to be moved at the initial stage followed by a rapid force diminish.
Tsafnat, N., Tsafnat, G. & Jones, A.S. 2008, 'Micro-finite element modelling of coke blends using X-ray microtomography', Fuel, vol. 87, no. 13-14, pp. 2983-2987.
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X-ray micro-computed tomography (microCT) is a non-destructive method of visualising specimens in three dimensions at the micrometer scale. Finite element analysis (FEA) is a method for approximating the structural response of systems to mechanical loading. The two methods are readily combined in micro-finite element analysis (microFEA). The microCT image, already in the discretized form of voxels, can be directly converted into a finite element mesh allowing materials with complex microstructures to be modelled. In this paper we present an example of microFEA model construction and use in the study of coke, a porous mineral. MicroCT datasets of different coke blends were used to create finite element models. The models were used to examine the material's structural response to compressive loading by studying the resultant stress distributions and material deformation. MicroFEA can be used to advance our understanding of the relationship between porous materials' microstructure and their bulk properties. &copy; 2008 Elsevier Ltd. All rights reserved.
Omar, H., Shen, G., Jones, A.S., Zoellner, H., Petocz, P. & Darendeliler, M.A. 2008, 'Effect of low magnitude and high frequency mechanical stimuli on defects healing in cranial bones.', J Oral Maxillofac Surg, vol. 66, no. 6, pp. 1104-1111.
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PURPOSE: The aim of this investigation was to assess the effect of low magnitude high frequency (LMHF) mechanical vibrated stimulation on healing the defects surgically imposed on craniofacial bones. MATERIALS AND METHODS: Forty 12-week-old C3H strain mice were separated into surgical and non-surgical groups. The surgical groups had a reproducible surgical bony lesion prepared in their right parietal bone. Both groups were further subdivided into vibration (experimental) and non-vibration (control) groups at 3 time points (zero hours, 2 weeks, and 4 weeks). The vibration groups were subjected to LMHF mechanical stimuli (30 Hz with peak strain 5 microepsilon) via a vibration machine for 20 minutes a day for 5 days a week for a total of 28 days. The specimens were analyzed using micro-computer tomography (micro-CT). RESULTS: Micro-CT volumetric measurement showed that in the surgical defects groups there was a significant decrease in the volume of the healing lesion with time (P < .001) and the linear decrease was significantly more pronounced in the vibration-treated group than the nontreated group (P < .001). Micro-CT histomorphometric measurement showed that in the nonsurgical groups there was no significant difference in microstructures of bony trabeculae between vibration-treated and nontreated groups. CONCLUSION: It is suggested that the introduction of LMHF mechanical stimuli in a healing bony lesion in the non-weight bearing bone significantly increases its healing capacity.
Greco, M., Jones, A., Spooner-Hart, R. & Holford, P. 2008, 'X-ray computerised microtomography (MicroCT): A new technique for assessing external and internal morphology of bees', Journal of Apicultural Research, vol. 47, no. 4, pp. 286-291.
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Traditionally, the classification of bees has been conducted with the aid of dissecting (light) microscopy. In more recent times, detailed information on external and internal morphology for bee classification has been obtained using scanning and transmission electron microscopy. MicroCT is emerging as a new method for non-invasive 3D computerised X-ray tomographic imaging of insects at the microscopic level and, in this study, has been evaluated for its use in morphological studies of bees. A Skyscan 1172 MicroCT system was used to assess the internal and external morphology of the Australian stingless bee Trigona carbonaria with particular focus on the proventricular plates. MicroCT was useful in non-invasively visualising gross external morphological features such as the articulations of the coxae, trochanters, tibiae and tarsi of each leg including broadened hind basitarsi. Image magnification revealed further detail such as antennal scapes and the various parts of the tongue including the proboscis and labium. However, the individual facets of the eye were barely discernable and MicroCT did not reveal fine details of hairs on the body or legs. Internal morphology was clearly visualised, including the tracheal system and details of the proventriculus and proventricular basal plates which form the leaflets of the proventricular valve. Thus, the characteristic features of the proventricular basal plates of Meliponini could be quickly and easily identified non-invasively. Therefore, MicroCT, as one of the emerging techniques of diagnostic radioentomology, has particular advantages for non-invasively and non-destructively imaging bees and, particularly, rare or more scientifically valued insects such as museum specimens and those trapped in amber. &copy; IBRA 2008.
Golding, R.E. & Jones, A.S. 2007, 'Micro-CT as a novel technique for 3D reconstruction of molluscan anatomy', Molluscan Research, vol. 27, no. 3, pp. 123-128.
X-ray micro-CT is demonstrated to be a novel technique to examine soft-tissue anatomy and is used here to reconstruct images of molluscan soft-tissue for the first time. Two micromolluscs ( > 1.8 mm diameter) were imaged using micro-CT, and then reconstructed to form 3D models of the tissues. Discrete organs of the alimentary system of large gastropods were also imaged. Osmium tetroxide and phosphomolybdic acid were identified as useful stains and a specimen preparation protocol is presented. Micro-CT is a rapid, non-destructive technique which complements and may in some circumstances replace traditional 3D reconstruction of molluscan specimens from histological sections. Micro-CT is faster and more spatially accurate than reconstruction from histological sections, but organs of a similar density are difficult to distinguish due to a lack of cellular detail. Copyright &copy; 2007 Malacological Society of Australasia.
Uzun, H., Curthoys, I.S. & Jones, A.S. 2007, 'A new approach to visualizing the membranous structures of the inner ear - high resolution X-ray micro-tomography.', Acta Otolaryngol, vol. 127, no. 6, pp. 568-573.
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CONCLUSION: Through the application of high resolution X-ray micro-tomography and a method of contrast enhancement based on en bloc staining in osmium tetroxide (OsO4), we report an approach that facilitates accurate three-dimensional (3D) reconstruction to reveal the fine structure of the inner ear. OBJECTIVES: To overcome the problems of artefacts, including tissue distortion and loss of 3D context that are inherent in existing methods that rely on manual dissection and/or histological sectioning. MATERIALS AND METHODS: A staining protocol was developed that involved the en bloc application of the OsO4 solution (2% w/v) for an extended period of time. The samples were then scanned using an X-ray micro-tomography platform and subsequent 3D visualizations were constructed. RESULTS: The digital nature of the data allowed a complete 3D contextual visualization to be constructed whereby the individual sensory structures could be seen in relation to other inner ear structures. This included a detailed anatomy of the membranous labyrinth and nerve supply including the spatial configuration of the utricular and saccular maculae. This is a new way of undertaking temporal bone histology.
Jones, A.S., Reztsov, A. & Loo, C.E. 2007, 'Application of invariant grey scale features for analysis of porous minerals', Micron, vol. 38, no. 1, pp. 40-48.
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Three-dimensional (3D) texture analysis can be used to differentiate similar materials which have a complex structural nature that is not easily reduced to geometric primitives. A method which extends the concept of invariant grey scale features to non-structured 3D textures is introduced and applied to the study of five processed mineral carbon materials which are characteristically similar but derive from different industrial sources. X-ray microtomography (XRMT) was used to obtain 3D tomographic data with isotropic voxel spacing of 9.8 m. These data were used to construct invariant features for 3D texture measurement via Monte Carlo based sampling routines and integrals of grey scale relational kernel functions. The procedure produced multi-component texture vectors, which were successfully tested against texture samples as a classification-recognition tool. Identification accuracies ranging from 69% to approximately 84% were achieved for the five material sources examined. This result provides a sound basis for quantitative analysis of these materials which to date have proved very difficult to examine using traditional image analysis tools because of their complex natural structure. &copy; 2006 Elsevier Ltd. All rights reserved.
Wang, Y., Chang, H.-.I., Wertheim, D.F., Jones, A.S., Jackson, C. & Coombes, A.G.A. 2007, 'Characterisation of the macroporosity of polycaprolactone-based biocomposites and release kinetics for drug delivery.', Biomaterials, vol. 28, no. 31, pp. 4619-4627.
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Microporous, biocomposite matrices comprising a continuous phase of poly(epsilon-caprolactone) (PCL) and a dispersed phase of lactose or gelatin particles with defined size range (45-90, 90-125 and 125-250 microm) were produced by precipitation casting from solutions of PCL in acetone. Scanning electron microscopy (SEM) analysis revealed a characteristic surface morphology of particulates interspersed amongst crystalline lamellae of the polymer phase. Rapid release of around 80% of the lactose content occurred in PBS at 37 degrees C in 3 days, whereas biocomposites containing gelatin particles of size range 90-125 and 125-250 microm, respectively, displayed gradual and highly efficient release of around 90% of the protein phase over 21 days. A highly porous structure was obtained on extraction of the water-soluble phase. Micro-computed tomography (Micro-CT) and image analysis enabled 3-D visualisation and quantification of the internal pore size distribution. A maximum fractional pore area of 10.5% was estimated for gelatin-loaded matrices. Micro-CT analysis confirmed the presence of an extensive system of macropores, sufficiently connected to permit protein diffusion, but an absence of high volume, inter-pore channels. Thus tissue integration would be confined to the matrix surface initially if the designs investigated were used as tissue-engineering scaffolds, with the core potentially providing a depot system for controlled delivery of growth factors.
Huang, T.T.Y., Jones, A.S., He, L.H., Darendeliler, M.A. & Swain, M.V. 2007, 'Characterisation of enamel white spot lesions using X-ray micro-tomography.', J Dent, vol. 35, no. 9, pp. 737-743.
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OBJECTIVES: The aim of this study was to characterise the mineral density (MD) of natural enamel white spot lesions (WSLs) using X-ray micro-tomography calibrated with different density hydroxyapatite phantoms. METHODS: Seven natural WSLs from four extracted non-carious premolar teeth were scanned at a voxel size of 7.6 microm using a desktop X-ray micro-tomography system. Five hydroxyapatite phantoms (sintered pellets of hydroxyapatite powder) with densities ranging from 1.52 to 3.14 g/cm(3) were used as calibration standards for each scan. Three-dimensional image reconstruction enabled MD gradients throughout the lesion to be quantified using an MD calibration equation derived from hydroxyapatite phantoms. Background noise generated during the measurement of MD was reduced using a Gaussian filter. RESULTS: Gaussian filter reduced the signal-to-noise ratio (standard deviation) significantly while the basic MD information (average value) remained intact. The mineral gradients through the WSLs examined were compared and are discussed in terms of existing literature. The MD of sound enamel, apparent intact surface layer of WSL, and lowest level of WSL was found to be 2.65-2.89 g/cm(3), 2.23-2.58 g/cm(3) and 1.48-2.03 g/cm(3), respectively. Our MD results are comparable with other studies. CONCLUSIONS: X-ray micro-tomography is a sensitive in vitro technique capable of characterising and quantifying MD of small non-cavitated WSLs. This method has a promising potential for future carious and quantitative remineralisation studies.
Uzun-Coruhlu, H., Curthoys, I.S. & Jones, A.S. 2007, 'Attachment of the utricular and saccular maculae to the temporal bone.', Hear Res, vol. 233, no. 1-2, pp. 77-85.
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The present investigation concerns the true morphology of the attachment of the two otolith receptor organs the utricular and the saccular maculae in two and three dimensions. By applying a new visualization method, which utilized the application of X-ray microtomography and a method of contrast enhancement based on en-bloc staining in osmium tetroxide, we were able to overcome problems of artefact production such as tissue distortion and loss of valuable information that was present in previous studies. A series of more than 1000 axial sections were obtained for each of the specimens, which subsequently formed the basis for detailed 2D and 3D visualizations. Our interpretations of these data reveal that the saccular maculae are closely attached to the curved bony surface of the temporal bone as traditionally believed, but the utricular macula is attached to the temporal bone only at the anterior region of the macula.
Foo, M., Jones, A. & Darendeliler, M.A. 2007, 'Physical properties of root cementum: Part 9. Effect of systemic fluoride intake on root resorption in rats.', Am J Orthod Dentofacial Orthop, vol. 131, no. 1, pp. 34-43.
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INTRODUCTION: Orthodontically induced inflammatory root resorption is a common complication in orthodontic treatment. Fluoride has been reported to have a beneficial effect against root resorption in dental traumatology. The effect of fluoride on orthodontically induced inflammatory root resorption has not been investigated. This study was undertaken to investigate the effect of fluoride on the incidence of root resorption. METHODS: Thirty-two female 8-week-old Wistar rats were separated into 4 groups. Two groups (6 rats per group) were controls; they did not undergo orthodontic tooth movement. The other 2 groups (10 rats per group) had orthodontic tooth movement consisting of activated 100-g closing nickel-titanium coils (NiTi 10-000-06, GAC International, Bohemia, NY) connecting the mandibular first molar to the incisors. Fluoridated water (100 ppm) was given ad libitum to 1 control and 1 experimental group. The other 2 groups received deionized water. After 2 weeks, the animals were killed, and the samples were harvested. Resorption craters were scanned with a Micro CT (SkyScan 1072, Aartselaar, Belgium). Software analysis of the scanned samples provided a volumetric measurement of the resorption craters on the mandibular molar cementum surface. RESULTS: Resorption sites were found in the control samples, especially on the distal surfaces; this could be attributed to normal physiological tooth drift. Resorption sites were significantly (P <.05) increased in the groups receiving orthodontic tooth movement. CONCLUSIONS: Fluoride reduces the size of resorption craters, but the effect is variable and not statistically significant (P >.05).
Harris, D.A., Jones, A.S. & Darendeliler, M.A. 2006, 'Physical properties of root cementum: part 8. Volumetric analysis of root resorption craters after application of controlled intrusive light and heavy orthodontic forces: a microcomputed tomography scan study.', Am J Orthod Dentofacial Orthop, vol. 130, no. 5, pp. 639-647.
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INTRODUCTION: Intrusion is a critical type of orthodontic tooth movement in relation to external root resorption. Our aims in this prospective randomized clinical trial were to quantify, 3 dimensionally, the amount of root resorption when controlled light and heavy intrusive forces were applied to human premolars and to establish the sites where root resorption is more prevalent. METHODS: Fifty-four maxillary first premolars, orthodontically indicated for extraction from 27 patients (left and right maxillary first premolars from each), were intruded for 28 days with buccal and palatal beta-titanium-molybdenum alloy 0.017 x 0.025-in cantilever springs. The patients were randomly divided into 3 groups, and various levels of force were used: group 1, heavy force (225 g) on 1 side and control force (0 g) on the contralateral side; group 2, light force (25 g) on 1 side and control force (0 g) on the contralateral side; group 3, light force (25 g) on 1 side and heavy force (225 g) on the contralateral side. After the experimental period, the teeth were extracted under a strict protocol to prevent root surface damage and analyzed by using a microcomputed tomography scan x-ray system (SkyScan-1072, Skyscan, Aartselaar, Belgium) and specially designed software for direct volumetric measurements. RESULTS: The volume of the root resorption craters after intrusion was found to be directly proportional to the magnitude of the intrusive force applied. The results showed that the control group had fewer and smaller root resorption craters, the light force group had more and larger root resorption craters than the control group, and the heavy force group had the most and the largest root resorption craters of all groups. A trend of linear increase in the volume of the root resorption craters was observed from control to light to heavy groups, and these differences were statistically significant. The mean volumes of the resorption craters in the light and heavy force groups were ...
Ananda, S., Marsden, V., Vekemans, K., Korkmaz, E., Tsafnat, N., Soon, L., Jones, A. & Braet, F. 2006, 'The visualization of hepatic vasculature by X-ray micro-computed tomography.', J Electron Microsc (Tokyo), vol. 55, no. 3, pp. 151-155.
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In this study, X-ray micro-computed tomography (CT) was used to reconstruct the fine structure macro- and microvasculature in three dimensions in contrast-enhanced rat liver samples. The subsequent application in the experimental CC531s colorectal cancer model was concurrent with results obtained from confocal microscopy in earlier studies. The en bloc stains osmium tetroxide in combination with uranyl acetate provided an excellent contrasting result for hepatic tissue after a trial of several contrasting agents. X-ray micro-CT allowed us to image the large blood vessels together with the branching sinusoids of hepatic tissue in three dimensions. Furthermore, interruption of the microvasculature was noted when rats were injected with CC531s colorectal cancer cells indicating the presence of hepatic metastases.
Burrow, C.J., Jones, A.S. & Young, G.C. 2006, 'Erratum to "X-ray microtomography of 410 million-year-old optic capsules from placoderm fishes" (DOI:10.1016/j.micron.2005.05.005)', Micron, vol. 37, no. 4, p. 374.
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Dame Carroll, J.R., Chandra, A., Jones, A.S., Berend, N., Magnussen, J.S. & King, G.G. 2006, 'Airway dimensions measured from micro-computed tomography and high-resolution computed tomography.', Eur Respir J, vol. 28, no. 4, pp. 712-720.
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Volume averaging results in both over- and underestimation of airway dimensions when they are measured by high-resolution computed tomography (HRCT). The current authors calibrated computerised measurements of airway dimensions from HRCT against a novel three-dimensional micro-computed tomography (CT) standard, which has a 50-fold greater resolution, as well as against traditional morphometry. Inflation-fixed porcine lung cubes were scanned by HRCT and micro-CT. A total of 59 lumen area (Ai), 30 wall area (A(aw)) and 11 lumen volume (Vi) measurements were made. Ai was measured from the cut surface of 11 airways by morphometry. Airways in scanned images were matched using branching points. After calibration, the errors of Ai, A(aw) and Vi HRCT measurements were determined. The current authors found a systematic, size-dependent underestimation of Ai and overestimation of A(aw) from HRCT measurements. This was used to calibrate an HRCT measurement algorithm. The 95% limits of agreement of subsequent measurements were +/-3.2 mm2 for Ai, +/-4.3 mm2 for A(aw), and +/-11.2 mm3 for Vi with no systematic error. Morphometric measurements agreed with micro-CT (+/-2.5 mm2) without systematic error. In conclusion, micro-computed tomography image data from inflation-fixed airways can be used as calibration standards for three-dimensional lumen volume measurements from high-resolution computed tomography, while morphometry is acceptable for two-dimensional measurements. The image dataset could be used to validate other developmental three-dimensional segmentation algorithms.
Ratinac, K.R., Gilbert, R.G., Ye, L., Jones, A.S. & Ringer, S.P. 2006, 'The effects of processing and organoclay properties on the structure of poly(methyl methacrylate)-clay nanocomposites', Polymer, vol. 47, no. 18, pp. 6337-6361.
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A variety of nanocomposites were synthesised by bulk polymerisation of methyl methacrylate (MMA), and also by extrusion of poly(methyl methacrylate) (PMMA). These were characterised by wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). We applied image analysis to the TEM images of these PMMA-clay nanocomposites to quantify their structures; an analysis was made of the resulting parameters to determine which were most useful for quantifying the microscale and nanoscale structures. Frequently, these quantitative results differed from those expected on the basis of WAXD, demonstrating the limitations of using diffraction data as the sole measure of nanocomposite structure. By combining the quantitative parameters from TEM with the WAXD data, we have explored the effects of processing conditions and organoclay properties on final nanocomposite structure. Factors examined included the effect of the reactivity of the surface modifiers, platelet size, the incorporation of excess modifier within the organoclay, and bulk polymerisation versus extrusion. &copy; 2006 Elsevier Ltd. All rights reserved.
Burrow, C.J., Jones, A.S. & Young, G.C. 2005, 'X-ray microtomography of 410 million-year-old optic capsules from placoderm fishes.', Micron, vol. 36, no. 6, pp. 551-557.
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The structure of two small ossified optic capsules from mid-Palaeozoic placoderm fishes has been revealed in fine detail, by the use of X-ray microtomography analysis and 3D visualisation software. These two specimens are 410 million-year-old; they were collected from an Early Devonian (Lochkovian) limestone in central New South Wales, and are the oldest known optic capsules from jawed fishes. The capsules show attachment areas for seven extrinsic eye muscles, rather than the six until recently deemed universal for gnathostomes. The analysis also revealed structures within the ossified cartilage which covered the medial surface of the eyeball, including nerve tracts, vascular canals, and possibly a choroid rete mirabile.
Zheng, Q., Milthorpe, B.K. & Jones, A.S. 2004, 'Direct Neural Network Application for Automated Cell Recognition', Cytometry, vol. 57A, no. 1, pp. 1-9.
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Background Automated cell recognition from histologic images is a very complex task. Traditionally, the image is segmented by some methods chosen to suit the image type, the objects are measured, and then a classifier is used to determine cell type from the object's measurements. Different classifiers have been used with reasonable success, including neural networks working with data from morphometric analysis. Methods Image data of cells were input directly into neural networks to determine the feasibility of direct classification by using pixel intensity information. Several types of neural network and their ability to work with cells in a complex patterned background were assessed for a variety of images and cell types and for the accuracy of classification. Results Inflammatory cells from animal biomaterial implants in rabbit paravertebral muscle were imaged in histologic sections. Simple, three-layer, fully connected, back-propagation neural networks and four-layer networks with two layers of a shared-weights neural network were most successful at classifying the cells from the images, with 97% and 98% correct recognition rates, respectively. Conclusions The high accuracy recognition rate shows the potential for direct classification of visual image pixel data by neural networks.
Chan, E.K.M., Darendeliler, M.A., Petocz, P. & Jones, A.S. 2004, 'A new method for volumetric measurement of orthodontically induced root resorption craters.', Eur J Oral Sci, vol. 112, no. 2, pp. 134-139.
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This method was designed to quantify root resorption on human premolar root surfaces induced by orthodontic forces by volume. Light (25 g) or heavy (225 g) orthodontic forces were applied to 20 first maxillary premolars in 10 human subjects. The contralateral teeth of the subjects served as controls. All teeth were extracted after 28 d of experimentation and prepared for imaging. A pair of stereo scanning electron microscopy (SEM) images (+/-3 degrees ) of resorption craters was captured and imported into an image analysis software package. The images were aligned and grayscale depth maps of the craters were generated. Correction for errors due to residual tilt and curvature of the cementum surface using shading correction was performed. Thresholding was used to obtain a measure of both the cementum surface height and the average depth of the crater. The depth of the crater was the difference in these values. Crater volumes were obtained by multiplication of the average of this difference by area of the crater. Calibration of this volumetric measurement against standardized calculated known volumes on metallic rods showed good accuracy and reproducibility. In the experimental teeth, heavy forces caused threefold more resorption than light forces (P < 0.01). There was also more root resorption evident in the experimental teeth compared with the control teeth in both the light and heavy force groups.
Chan, E.K.M., Darendeliler, M.A., Jones, A.S. & Kaplin, I.J. 2004, 'A calibration method used for volumetric measurement of orthodontically induced root resorption craters.', Ann Biomed Eng, vol. 32, no. 6, pp. 880-888.
The aim of this study was to measure the accuracy and reproducibility of volumetric estimations obtained by a commercial software used to measure resorption craters induced by orthodontic forces. Twenty human first maxillary premolars were selected and divided into light and heavy force groups with 25 and 225 g of force applied to the upper-right first premolars, respectively. The contralateral teeth served as controls. Samples were extracted and prepared for SEM stereoimaging after 28 days of force application. Volumetric measurements of these resorption craters were generated by the software. Standardized pyramidal indentations by the Vickers microhardness tester on four solid metallic cylindrical rods (brass, copper, stainless steel, and aluminum) similar to the dimensions of human premolars were used for calibration. Mathematically calculated volumes of these indentations were compared to volumes estimated by the software. The software estimated the errors of volumes of pyramidal indentations of the harder and softer materials to within 11 and 19%, respectively. Non-uniform plastic deformation that occurred in softer materials during indentation distorts the calculated results. The estimates obtained by the software even for distorted indentations caused by non-uniform plastic deformation have high degrees of reproducibility and accuracy.
Darendeliler, M.A., Kharbanda, O.P., Chan, E.K.M., Srivicharnkul, P., Rex, T., Swain, M.V., Jones, A.S. & Petocz, P. 2004, 'Root resorption and its association with alterations in physical properties, mineral contents and resorption craters in human premolars following application of light and heavy controlled orthodontic forces', Orthodontics and Craniofacial Research, vol. 7, no. 2, pp. 79-97.
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Objectives: To study the effect of different orthodontic force levels on cementum, investigating from the point of view of its physical properties, alterations in the mineral components, type and location of the resorption craters and the exploration in 3D of space. Design: In vivo human premolars subjected to heavy and light forces were employed for this study. After a period of movement they were analyzed for hardness and elasticity. Also, the mineral composition measuring Ca, P and F of the cementum root surface was investigated. A new method for volumetric analysis of resorption craters was developed. Results: There were no significant differences for hardness and elastic modulus between the light and heavy force groups and no significant effects for different tooth positions. Significant inter-individual variation in the Ca, P and F concentrations was noted. Force-related data showed that mean volume of the resorption crater in light-force group was 3.49-fold greater than the control group, and the heavy-force group 11.59-fold more than control group. The heavy force group had 3.31-fold greater total resorption volume then light force group. Buccal cervical and lingual apical regions demonstrated significantly more resorption craters than the other regions. The 2D measurements were strongly correlated to 3D measurements. Conclusion: The application of light and heavy forces did not show any statistically significant differences in hardness and elastic modulus when compared with untreated teeth. The inconsistent increase or decrease of Ca, P and F contents between control and experimental teeth at sites of compression and tension were difficult to explain. There was more resorption by volume in the heavy force group as compared with the light group and controls. Our data also suggested that the highpressure zones might be more susceptible to resorption after 28 days of force application. &copy; Blackwell Munksgaard 2004.
Cox, G., Kable, E., Jones, A., Fraser, I., Manconi, F. & Gorrell, M.D. 2003, '3-dimensional imaging of collagen using second harmonic generation.', J Struct Biol, vol. 141, no. 1, pp. 53-62.
Collagen is the most important structural protein of the animal body. Its unique triple-helix structure and extremely high level of crystallinity make it exceptionally efficient in generating the second harmonic of incident light, and we show here how this leads to a novel mode of microscopy of immediate practical significance in medicine and biology. In particular, it provides sensitive and high-resolution information on collagen distribution, discriminates between type I and type III collagen, and allows both a greater understanding of and a sensitive test for cirrhosis of the liver. Future research applications could include wound healing and hereditary collagen diseases such as osteogenesis imperfecta.
Gaus, K., Gratton, E., Kable, E.P.W., Jones, A.S., Gelissen, I., Kritharides, L. & Jessup, W. 2003, 'Visualizing lipid structure and raft domains in living cells with two-photon microscopy.', Proc Natl Acad Sci U S A, vol. 100, no. 26, pp. 15554-15559.
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The lateral organization of cellular membranes is formed by the clustering of specific lipids, such as cholesterol and sphingolipids, into highly condensed domains (termed lipid rafts). Hence such domains are distinct from the remaining membrane by their lipid structure (liquid-ordered vs. -disordered domains). Here, we directly visualize membrane lipid structure of living cells by using two-photon microscopy. In macrophages, liquid-ordered domains are particularly enriched on membrane protrusions (filopodia), adhesion points and cell-cell contacts and cover 10-15% of the cell surface at 37 degrees C. By deconvoluting the images, we demonstrate the existence of phase separation in vivo. We compare the properties of microscopically visible domains (<1 microm2), with those of isolated detergent-resistant membranes and provide evidence that membrane coverage by lipid rafts and their fluidity are principally governed by cholesterol content, thereby providing strong support for the lipid raft hypothesis.
De Lucca, S.D., Taylor, D.J., O'Meara, T.J., Jones, A.S. & Tovey, E.R. 1999, 'Measurement and characterization of cockroach allergens detected during normal domestic activity.', J Allergy Clin Immunol, vol. 104, no. 3 Pt 1, pp. 672-680.
BACKGROUND: Cockroach allergen is recognized as a causal factor for asthma. However, airborne cockroach allergen has not been detected in undisturbed conditions, and therefore the behavior and properties of airborne cockroach allergen have been poorly characterized. A new aeroallergen sampling method and sensitive system of immunoassay have been used to examine cockroach allergen exposure. OBJECTIVE: Our purpose was to measure and characterize airborne cockroach allergens during normal domestic exposure in the homes of Sydney, Australia. METHODS: Air sampling with Institute of Occupational Medicine, Edinburgh (IOM) samplers was performed in the living rooms of 10 houses during low- and no-disturbance environments. In addition, inhaled particles were collected by each home occupant during low domestic exposure with use of intra-nasal samplers that impact particles onto an adhesive surface. The particles collected on the IOMs and the intra-nasal samplers were immunostained with Bla g 1 monoclonal antibodies. Particle size, morphologic characteristics, and the relative Bla g 1 content of particles were estimated. Reservoir dust samples from the kitchen, living room, and bedroom were assayed by an ELISA. Two forms of repeatability of IOM air sampling were examined. The first measure tested the repeatability of 2 IOM samples collected simultaneously in the same room during low- and no-disturbance activities. The second measure examined the repeatability of IOM sampling over time on 10 consecutive days. RESULTS: Bla g 1 was detected in reservoir dust samples taken from all homes (geometric mean 1.5 U/g, range 0.2-9.4 U/g). Inhaled particles containing Bla g 1 were detected during 1 hour of intra-nasal sampling in 8 of 10 homes during low disturbance. Cockroach particles were detected on all of the IOM samples collected for both 4-hour low-disturbance and overnight no-disturbance sampling environments. Particles containing Bla g 1 collected with the IOM samplers during ...
Benyon, F.H.L., Jones, A.S., Tovey, E.R. & Stone, G. 1999, 'Differentiation of allergenic fungal spores by image analysis, with application to aerobiological counts', Aerobiologia, vol. 15, no. 3, pp. 211-223.
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The ability of an image analysis routine to differentiate between spores of eleven allergenic fungal genera was tested using analysis based on seven basic and up to 17 more complex features, extracted from digitised images. Fungal spores of Alternaria, Cladosporium, Fusarium, Aspergillus, Penicillium, Botrytis, Epicoccum, Exserohilum, Ustilago, Coprinus and Psilocybe were examined in a series of experiments designed to differentiate between spores at the genus and species level. Linear and Quadratic Discriminant Analysis of feature measurements, recorded for 100 to 1600 spores per taxon, differentiated between genera and species with a high level of accuracy. Genus comparisons using only seven basic features resulted in 98% accuracy for the recognition of conidia belonging to Cladosporium, Fusarium and Epicoccum. Differentiation between Conidia of Aspergillus and Penicillium was the least reliable, with 56% of Aspergillus conidia correctly identified and 41% misidentified as Penicillium. At the species level, conidia of Cladosporium macrocarpum, Fusarium moniliforme (microconidia), F. oxysporum (microconidia), F. solani (macroconidia), Alternaria helianthi and A. brassicae were consistently identified with 86-100% accuracy. Reduced levels of accuracy in the identification of spores by image analysis reflected similarities between species in their spore morphology. The application of image analysis to aerobiological counting methods is discussed in relation to the results obtained.
Salih, A., Jones, A.S., Bass, D. & Cox, G. 1997, 'Confocal imaging of exine as a tool for grass pollen analysis', Grana, vol. 36, no. 4, pp. 215-224.
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A new method which utilises confocal optical imaging has been developed which can be expected to improve grass pollen analysis. Confocal microscopy, in reflection mode, was used to examine the exine morphology of unacetolysed pollen grains from the following species of common wild grasses: Paspalum dilatatum, Setaria gracilis, Bromus catharticus, Daclylis glomerata, Lolium perenne, Poa pratensis, and Phalaris aquatica. Variations in the surface texture patterns, similar to those hitherto only seen by scanning electron microscopy, were visualised. In contrast to the latter method, specimen preparation for this confocal microscopy based technique was characterised by its simplicity, permitting the use of fresh and chemically untreated pollen grains. This confocal imaging technique, with its capacity for optical sectioning of specimens, offered the additional advantage of allowing the examination of the sub-surface exine layers as well as the surface morphology of the pollen grains. Furthermore, three-dimensional reconstruction of these optical sections enabled visualisation of the identified sculptural and structural exine elements and layers. A number of differences in these patterns were found, which indicate that confocal microscopy, in combination with image analysis, may enable finer taxonomic distinctions to be made than those currently provided by other light microscope based methods. &copy; 1997 Taylor & Francis Group, LLC.
Jones, A.S., Milthorpe, B.K. & Howlett, C.R. 1994, 'Measurement of Microtomy Induced Section Distortion and Its Correction for 3-Dimensional Histological Reconstructions', Cytometry, vol. 15, no. 2, pp. 95-105.
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The presence of microtomy induced distortion in paraffin sections is a significant hindrance to the accurate alignment of sections for three-dimensional reconstructive techniques. Measurement of section distortion in various rat tissues demonstrated distortions to be present in all sections, with over 85% of such distortions being manifest as expansions when compared to the original distances between a series of eight drilled fiducial marks. Mean percentage dimensional changes in the direction of the cutting stroke and at right angles to this direction were -0.5 &plusmn; 1.5% and 3.7 &plusmn; 1.2% for liver, 7.6 &plusmn; 2.4% and 9.1 &plusmn; 1.2% for kidney, 6.6 &plusmn; 2.3% and 10.5 &plusmn; 1.4% for lung, and 20.3 &plusmn; 6.6% and 8.9 &plusmn; 5.9% for skeletal muscle. Individual sections invariably displayed measurable distortions, with only skeletal muscle showing any consistent pattern, in the form of barrel distortion at right angles to the cutting stroke. In addition a method of distortion correction and simultaneous image alignment is presented as a means of section alignment with full distortion correction capability. This method uses a quadratic polynomial transform in a non-linear unwarping algorithm, to correct for the rotational and translational misalignment as well as for microtomy and camera aspect ratio distortions. Application of this method to a sequence of 46 serial sections demonstrated an alignment accuracy to within 2.6 &plusmn; 0.8 pixels