Insights from echocardiography, magnetic resonance imaging, and microcomputed tomography relative to the mid-myocardial left ventricular echogenic zone.

PubMed

Agger, Peter; Stephenson, Robert S; Dobrzynski, Halina; Atkinson, Andrew; Iaizzo, Paul A; Anderson, Robert H; Jarvis, Jonathan C; Allan, Sarah L; Partridge, John B; Zhao, Jichao; Zhang, Henggui; MacIver, David H

2016-10-01

The anatomical substrate for the mid-mural ventricular hyperechogenic zone remains uncertain, but it may represent no more than ultrasound reflected from cardiomyocytes orientated orthogonally to the ultrasonic beam. We sought to ascertain the relationship between the echogenic zone and the orientation of the cardiomyocytes. We used 3D echocardiography, diffusion tensor imaging, and microcomputed tomography to analyze the location and orientation of cardiomyocytes within the echogenic zone. We demonstrated that visualization of the echogenic zone is dependent on the position of the transducer and is most clearly seen from the apical window. Diffusion tensor imaging and microcomputed tomography show that the echogenic zone seen from the apical window corresponds to the position of the circumferentially orientated cardiomyocytes. An oblique band seen in the parasternal view relates to cardiomyocytes orientated orthogonally to the ultrasonic beam. The mid-mural ventricular hyperechogenic zone represents reflected ultrasound from cardiomyocytes aligned orthogonal to the ultrasonic beam. The echogenic zone does not represent a space, a connective tissue sheet, a boundary between ascending and descending limbs of a hypothetical helical ventricular myocardial band, nor an abrupt change in cardiomyocyte orientation. © 2016, Wiley Periodicals, Inc.

Comparative evaluation of root canal preparations of maxillary first molars with self-adjusting file, reciproc single file, and revo-s rotary file: A micro-computed tomography study.

PubMed

Ahmetoglu, Fuat; Keles, Ali; Simsek, Neslihan; Ocak, M Sinan; Yologlu, Saim

2015-01-01

This study was aimed to use micro-computed tomography (μ-CT) to evaluate the canal shaping properties of three nickel-titanium instruments, Self-Adjusting File (SAF), Reciproc, and Revo-S rotary file, in maxillary first molars. Thirty maxillary molars were scanned preoperatively by using micro-computed tomography (μ-CT) scans at 13,68 μm resolution. The teeth were randomly assigned to three groups (n = 10). The root canals were shaped with SAF, Reciproc, and Revo-S, respectively. The shaped root canals were rescanned. Changes in canal volumes and surface areas were compared with preoperative values. The data were analyzed using Kruskal-Wallis and Conover's post hoc tests, with p < .05 denoting a statistically significant difference. Preoperatively canal volumes and surface area were statistically similar among the three groups (p > .05). There were statistically significant differences in all measures comparing preoperative and postoperative canal models (p = 0.0001). These differences occurred after instrumentation among the three experimental groups showed no statistically significant difference for volume (p > .05). Surface area showed the similar activity in buccal canals in each of the three techniques whereas no statistically significant difference was detected among surface area, the SAF, and the Revo-S in the palatal (P) canal. Each of three shaping system showed the similar volume activity in all canals, but SAF and Revo-S provided more effectively root planning in comparison with Reciproc in P canal. © Wiley Periodicals, Inc.

Presence of Voids after Continuous Wave of Condensation and Single-cone Obturation in Mandibular Molars: A Micro-computed Tomography Analysis.

PubMed

Iglecias, Elaine Faga; Freire, Laila Gonzales; de Miranda Candeiro, George Táccio; Dos Santos, Marcelo; Antoniazzi, João Humberto; Gavini, Giulio

2017-04-01

The objective of this study was to assess the presence of voids in mesial root canals of mandibular molar teeth obturated by using the single-cone (SC) and continuous wave of condensation (CWC) obturation techniques, and results were analyzed by using micro-computed tomography. Twenty-four mandibular molars with fully developed roots and mesial root curvature ranging from 25° to 35° were instrumented by using Reciproc R25 files, and then they were obturated by using the SC and CWC techniques. Specimens were scanned before and after obturation for micro-computed tomography analysis (voxel size, 17.42 μm). After volumetric analysis and tridimensional reconstruction of the root canals, data were analyzed by using analysis of variance and the Tukey test. No significant differences were observed between the 2 techniques in terms of total percentage volume of voids: CWC = 3.91% ± 0.72%; SC = 6.52% ± 1.16% (P > .05). Only in the cervical third, CWC showed a significantly lower percentage of voids when compared with SC, namely 2.86% ± 0.94% vs 8.00% ± 1.86%, respectively (P < .05). The percentage volume of voids was similar in the 2 groups and was influenced by the obturation technique only in the cervical third. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Image interpolation allows accurate quantitative bone morphometry in registered micro-computed tomography scans.

PubMed

Schulte, Friederike A; Lambers, Floor M; Mueller, Thomas L; Stauber, Martin; Müller, Ralph

2014-04-01

Time-lapsed in vivo micro-computed tomography is a powerful tool to analyse longitudinal changes in the bone micro-architecture. Registration can overcome problems associated with spatial misalignment between scans; however, it requires image interpolation which might affect the outcome of a subsequent bone morphometric analysis. The impact of the interpolation error itself, though, has not been quantified to date. Therefore, the purpose of this ex vivo study was to elaborate the effect of different interpolator schemes [nearest neighbour, tri-linear and B-spline (BSP)] on bone morphometric indices. None of the interpolator schemes led to significant differences between interpolated and non-interpolated images, with the lowest interpolation error found for BSPs (1.4%). Furthermore, depending on the interpolator, the processing order of registration, Gaussian filtration and binarisation played a role. Independent from the interpolator, the present findings suggest that the evaluation of bone morphometry should be done with images registered using greyscale information.

An application framework of three-dimensional reconstruction and measurement for endodontic research.

PubMed

Gao, Yuan; Peters, Ove A; Wu, Hongkun; Zhou, Xuedong

2009-02-01

The purpose of this study was to customize an application framework by using the MeVisLab image processing and visualization platform for three-dimensional reconstruction and assessment of tooth and root canal morphology. One maxillary first molar was scanned before and after preparation with ProTaper by using micro-computed tomography. With a customized application framework based on MeVisLab, internal and external anatomy was reconstructed. Furthermore, the dimensions of root canal and radicular dentin were quantified, and effects of canal preparation were assessed. Finally, a virtual preparation with risk analysis was performed to simulate the removal of a broken instrument. This application framework provided an economical platform and met current requirements of endodontic research. The broad-based use of high-quality free software and the resulting exchange of experience might help to improve the quality of endodontic research with micro-computed tomography.

Three-dimensional evaluation of human jaw bone microarchitecture: correlation between the microarchitectural parameters of cone beam computed tomography and micro-computer tomography.

PubMed

Kim, Jo-Eun; Yi, Won-Jin; Heo, Min-Suk; Lee, Sam-Sun; Choi, Soon-Chul; Huh, Kyung-Hoe

2015-12-01

To evaluate the potential feasibility of cone beam computed tomography (CBCT) in the assessment of trabecular bone microarchitecture. Sixty-eight specimens from four pairs of human jaw were scanned using both micro-computed tomography (micro-CT) of 19.37-μm voxel size and CBCT of 100-μm voxel size. The correlation of 3-dimensional parameters between CBCT and micro-CT was evaluated. All parameters, except bone-specific surface and trabecular thickness, showed linear correlations between the 2 imaging modalities (P < .05). Among the parameters, bone volume, percent bone volume, trabecular separation, and degree of anisotropy (DA) of CBCT images showed strong correlations with those of micro-CT images. DA showed the strongest correlation (r = 0.693). Most microarchitectural parameters from CBCT were correlated with those from micro-CT. Some microarchitectural parameters, especially DA, could be used as strong predictors of bone quality in the human jaw. Copyright © 2015 Elsevier Inc. All rights reserved.

The Effect of Experimental Variables on Industrial X-Ray Micro-Computed Sensitivity

NASA Technical Reports Server (NTRS)

Roth, Don J.; Rauser, Richard W.

2014-01-01

A study was performed on the effect of experimental variables on radiographic sensitivity (image quality) in x-ray micro-computed tomography images for a high density thin wall metallic cylinder containing micro-EDM holes. Image quality was evaluated in terms of signal-to-noise ratio, flaw detectability, and feature sharpness. The variables included: day-to-day reproducibility, current, integration time, voltage, filtering, number of frame averages, number of projection views, beam width, effective object radius, binning, orientation of sample, acquisition angle range (180deg to 360deg), and directional versus transmission tube.

Unimpeded permeation of water through biocidal graphene oxide sheets anchored on to 3D porous polyolefinic membranes.

PubMed

Mural, Prasanna Kumar S; Jain, Shubham; Kumar, Sachin; Madras, Giridhar; Bose, Suryasarathi

2016-04-21

3D porous membranes were developed by etching one of the phases (here PEO, polyethylene oxide) from melt-mixed PE/PEO binary blends. Herein, we have systematically discussed the development of these membranes using X-ray micro-computed tomography. The 3D tomograms of the extruded strands and hot-pressed samples revealed a clear picture as to how the morphology develops and coarsens over a function of time during post-processing operations like compression molding. The coarsening of PE/PEO blends was traced using X-ray micro-computed tomography and scanning electron microscopy (SEM) of annealed blends at different times. It is now understood from X-ray micro-computed tomography that by the addition of a compatibilizer (here lightly maleated PE), a stable morphology can be visualized in 3D. In order to anchor biocidal graphene oxide sheets onto these 3D porous membranes, the PE membranes were chemically modified with acid/ethylene diamine treatment to anchor the GO sheets which were further confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and surface Raman mapping. The transport properties through the membrane clearly reveal unimpeded permeation of water which suggests that anchoring GO on to the membranes does not clog the pores. Antibacterial studies through the direct contact of bacteria with GO anchored PE membranes resulted in 99% of bacterial inactivation. The possible bacterial inactivation through physical disruption of the bacterial cell wall and/or reactive oxygen species (ROS) is discussed herein. Thus this study opens new avenues in designing polyolefin based antibacterial 3D porous membranes for water purification.

Root Canal Morphology and Configuration of 118 Mandibular First Molars by Means of Micro-Computed Tomography: An Ex Vivo Study.

PubMed

Wolf, Thomas Gerhard; Paqué, Frank; Zeller, Maximilian; Willershausen, Brita; Briseño-Marroquín, Benjamín

2016-04-01

The aim of this study was to investigate the root canal system morphology of the mandibular first molar by means of micro-computed tomography. The root canal configuration, foramina, and accessory canals frequency of 118 mandibular first molars were investigated by means of micro-computed tomography and 3-dimensional software imaging. A 4-digit system describes the root canal configuration from the coronal to apical thirds and the main foramina number. The most frequent root canal configurations in mesial root were 2-2-2/2 (31.4%), 2-2-1/1 (15.3%), and 2-2-2/3 (11.9%); another 24 different root canal configurations were observed in this root. A 1-1-1/1 (58.5%), 1-1-1/2 (10.2%), and 16 other root canal configurations were observed in the distal root. The mesiobuccal root canal showed 1-4 foramina in 24.6%, and the mesiolingual showed 1-3 foramina in 28.0%. One connecting canal between the mesial root canals was observed in 30.5% and 2 in 3.4%. The distolingual root canal showed 1-4 foramina in 23.7%, whereas a foramen in the distobuccal root canal was rarely detected (3.4%). The mesiobuccal, mesiolingual, and distolingual root canals showed at least 1 accessory canal (14.3, 10.2, and 4.2%, respectively), but the distobuccal had none. The root canal configuration of mandibular first molars varies strongly. According to our expectations, both the mesial and distal roots showed a high number of morphologic diversifications. The root canal system of the mesial root showed more root canal configuration variations, connecting and accessory canals than the distal root. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Comparisons of the diagnostic accuracies of optical coherence tomography, micro-computed tomography, and histology in periodontal disease: an ex vivo study

PubMed Central

2017-01-01

Purpose Optical coherence tomography (OCT) is a noninvasive diagnostic technique that may be useful for both qualitative and quantitative analyses of the periodontium. Micro-computed tomography (micro-CT) is another noninvasive imaging technique capable of providing submicron spatial resolution. The purpose of this study was to present periodontal images obtained using ex vivo dental OCT and to compare OCT images with micro-CT images and histologic sections. Methods Images of ex vivo canine periodontal structures were obtained using OCT. Biologic depth measurements made using OCT were compared to measurements made on histologic sections prepared from the same sites. Visual comparisons were made among OCT, micro-CT, and histologic sections to evaluate whether anatomical details were accurately revealed by OCT. Results The periodontal tissue contour, gingival sulcus, and the presence of supragingival and subgingival calculus could be visualized using OCT. OCT was able to depict the surface topography of the dentogingival complex with higher resolution than micro-CT, but the imaging depth was typically limited to 1.2–1.5 mm. Biologic depth measurements made using OCT were a mean of 0.51 mm shallower than the histologic measurements. Conclusions Dental OCT as used in this study was able to generate high-resolution, cross-sectional images of the superficial portions of periodontal structures. Improvements in imaging depth and the development of an intraoral sensor are likely to make OCT a useful technique for periodontal applications. PMID:28261522

Terahertz Computed Tomography of NASA Thermal Protection System Materials

NASA Technical Reports Server (NTRS)

Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

2011-01-01

A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 cubic meters (1 cubic foot) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Morphological imaging and quantification of axial xylem tissue in Fraxinus excelsior L. through X-ray micro-computed tomography.

PubMed

Koddenberg, Tim; Militz, Holger

2018-05-05

The popularity of X-ray based imaging methods has continued to increase in research domains. In wood research, X-ray micro-computed tomography (XμCT) is useful for structural studies examining the three-dimensional and complex xylem tissue of trees qualitatively and quantitatively. In this study, XμCT made it possible to visualize and quantify the spatial xylem organization of the angiosperm species Fraxinus excelsior L. on the microscopic level. Through image analysis, it was possible to determine morphological characteristics of the cellular axial tissue (vessel elements, fibers, and axial parenchyma cells) three-dimensionally. X-ray imaging at high resolutions provides very distinct visual insight into the xylem structure. Numerical analyses performed through semi-automatic procedures made it possible to quickly quantify cell characteristics (length, diameter, and volume of cells). Use of various spatial resolutions (0.87-5 μm) revealed boundaries users should be aware of. Nevertheless, our findings, both qualitative and quantitative, demonstrate XμCT to be a valuable tool for studying the spatial cell morphology of F. excelsior. Copyright © 2018. Published by Elsevier Ltd.

Advances in imaging: impact on studying craniofacial bone structure.

PubMed

Majumdar, S

2003-01-01

Methods for measuring the structure of craniofacial bones are discussed in this paper. In addition to the three-dimensional macro-structure of the craniofacial skeleton, there is considerable interest in imaging the bone at a microscopic resolution in order to depict the micro-architecture of the trabecular bone itself. In addition to the density of the bone, the microarchitecture reflects bone quality. An understanding of bone quality and density changes has implications for a number of craniofacial pathologies, as well as for implant design and understanding the biomechanical function and loading of the jaw. Trabecular bone micro-architecture has been recently imaged using imaging methods such as micro-computed tomography, magnetic resonance imaging, and the images have been used in finite element models to assess bone mechanical properties. In this paper, some of the recent advances in micro-computed tomography and magnetic resonance imaging are reviewed, and their potential for imaging the trabecular bone in mandibular bones is presented. Examples of in vitro and in vivo images are presented.

Grapevine petioles are more sensitive to drought induced embolism than stems: evidence from in vivo MRI and microcomputed tomography observations of hydraulic vulnerability segmentation.

PubMed

Hochberg, Uri; Albuquerque, Caetano; Rachmilevitch, Shimon; Cochard, Herve; David-Schwartz, Rakefet; Brodersen, Craig R; McElrone, Andrew; Windt, Carel W

2016-09-01

The 'hydraulic vulnerability segmentation' hypothesis predicts that expendable distal organs are more susceptible to water stress-induced embolism than the main stem of the plant. In the current work, we present the first in vivo visualization of this phenomenon. In two separate experiments, using magnetic resonance imaging or synchrotron-based microcomputed tomography, grapevines (Vitis vinifera) were dehydrated while simultaneously scanning the main stems and petioles for the occurrence of emboli at different xylem pressures (Ψx ). Magnetic resonance imaging revealed that 50% of the conductive xylem area of the petioles was embolized at a Ψx of -1.54 MPa, whereas the stems did not reach similar losses until -1.9 MPa. Microcomputed tomography confirmed these findings, showing that approximately half the vessels in the petioles were embolized at a Ψx of -1.6 MPa, whereas only few were embolized in the stems. Petioles were shown to be more resistant to water stress-induced embolism than previously measured with invasive hydraulic methods. The results provide the first direct evidence for the hydraulic vulnerability segmentation hypothesis and highlight its importance in grapevine responses to severe water stress. Additionally, these data suggest that air entry through the petiole into the stem is unlikely in grapevines during drought. © 2015 John Wiley & Sons Ltd.

Digital tomosynthesis and high resolution computed tomography as clinical tools for vertebral endplate topography measurements: Comparison with microcomputed tomography.

PubMed

Oravec, Daniel; Quazi, Abrar; Xiao, Angela; Yang, Ellen; Zauel, Roger; Flynn, Michael J; Yeni, Yener N

2015-12-01

Endplate morphology is understood to play an important role in the mechanical behavior of vertebral bone as well as degenerative processes in spinal tissues; however, the utility of clinical imaging modalities in assessment of the vertebral endplate has been limited. The objective of this study was to evaluate the ability of two clinical imaging modalities (digital tomosynthesis, DTS; high resolution computed tomography, HRCT) to assess endplate topography by correlating the measurements to a microcomputed tomography (μCT) standard. DTS, HRCT, and μCT images of 117 cadaveric thoracolumbar vertebrae (T10-L1; 23 male, 19 female; ages 36-100 years) were segmented, and inferior and superior endplate surface topographical distribution parameters were calculated. Both DTS and HRCT showed statistically significant correlations with μCT approaching a moderate level of correlation at the superior endplate for all measured parameters (R(2)Adj=0.19-0.57), including averages, variability, and higher order statistical moments. Correlation of average depths at the inferior endplate was comparable to the superior case for both DTS and HRCT (R(2)Adj=0.14-0.51), while correlations became weak or nonsignificant for higher moments of the topography distribution. DTS was able to capture variations in the endplate topography to a slightly better extent than HRCT, and taken together with the higher speed and lower radiation cost of DTS than HRCT, DTS appears preferable for endplate measurements. Copyright © 2015 Elsevier Inc. All rights reserved.

Micro-computed tomography imaging and analysis in developmental biology and toxicology.

PubMed

Wise, L David; Winkelmann, Christopher T; Dogdas, Belma; Bagchi, Ansuman

2013-06-01

Micro-computed tomography (micro-CT) is a high resolution imaging technique that has expanded and strengthened in use since it was last reviewed in this journal in 2004. The technology has expanded to include more detailed analysis of bone, as well as soft tissues, by use of various contrast agents. It is increasingly applied to questions in developmental biology and developmental toxicology. Relatively high-throughput protocols now provide a powerful and efficient means to evaluate embryos and fetuses subjected to genetic manipulations or chemical exposures. This review provides an overview of the technology, including scanning, reconstruction, visualization, segmentation, and analysis of micro-CT generated images. This is followed by a review of more recent applications of the technology in some common laboratory species that highlight the diverse issues that can be addressed. Copyright © 2013 Wiley Periodicals, Inc.

Using synchrotron-based X-ray micro-computed tomography and high-performance pore-scale simulation to evaluate hydraulic properties in biochar-amended soils

NASA Astrophysics Data System (ADS)

Zhou, H.; Yu, X.; Chen, C.; Zeng, L.; Lu, S.; Wu, L.

2016-12-01

In this research, we combined synchrotron-based X-ray micro-computed tomography (SR-mCT), with three-dimensional lattice Bolzmann (LB) method, to quantify how the change in pore space architecture affected macroscopic hydraulic of two clayey soils amended with biochar. SR-mCT was used to characterize pore structures of the soils before and after biochar addition. The high-resolution soil pore structures were then directly used as internal boundary conditions for three-dimensional water flow simulations with the LB method, which was accelerated by graphics processing unit (GPU) parallel computing. It was shown that, due to the changes in soil pore geometry, the application of biochar increased the soil permeability by at least 1 order of magnitude, and decreased the tortuosity by 20-30%. This work was the first physics based modeling study on the effect of biochar amendment on soil hydraulic properties. The developed theories and techniques have promising potential in understanding the mechanisms of water and nutrient transport in soil at the pore scale.

Application of X-ray micro-computed tomography on high-speed cavitating diesel fuel flows

NASA Astrophysics Data System (ADS)

Mitroglou, N.; Lorenzi, M.; Santini, M.; Gavaises, M.

2016-11-01

The flow inside a purpose built enlarged single-orifice nozzle replica is quantified using time-averaged X-ray micro-computed tomography (micro-CT) and high-speed shadowgraphy. Results have been obtained at Reynolds and cavitation numbers similar to those of real-size injectors. Good agreement for the cavitation extent inside the orifice is found between the micro-CT and the corresponding temporal mean 2D cavitation image, as captured by the high-speed camera. However, the internal 3D structure of the developing cavitation cloud reveals a hollow vapour cloud ring formed at the hole entrance and extending only at the lower part of the hole due to the asymmetric flow entry. Moreover, the cavitation volume fraction exhibits a significant gradient along the orifice volume. The cavitation number and the needle valve lift seem to be the most influential operating parameters, while the Reynolds number seems to have only small effect for the range of values tested. Overall, the study demonstrates that use of micro-CT can be a reliable tool for cavitation in nozzle orifices operating under nominal steady-state conditions.

Laboratory and exterior decay of wood plastic composite boards: voids analysis and computed tomography

Treesearch

Grace Sun; Rebecca E. Ibach; Meghan Faillace; Marek Gnatowski; Jessie A. Glaeser; John Haight

2016-01-01

After exposure in the field and laboratory soil block culture testing, the void content of wood–plastic composite (WPC) decking boards was compared to unexposed samples. A void volume analysis was conducted based on calculations of sample density and from micro-computed tomography (microCT) data. It was found that reference WPC contains voids of different sizes from...

Quantification of Wear and Deformation in Different Configurations of Polyethylene Acetabular Cups Using Micro X-ray Computed Tomography

PubMed Central

Affatato, Saverio; Zanini, Filippo; Carmignato, Simone

2017-01-01

Wear is currently quantified as mass loss of the bearing materials measured using gravimetric methods. However, this method does not provide other information, such as volumetric loss or surface deviation. In this work, we validated a technique to quantify polyethylene wear in three different batches of ultrahigh-molecular-polyethylene acetabular cups used for hip implants using nondestructive microcomputed tomography. Three different configurations of polyethylene acetabular cups, previously tested under the ISO 14242 parameters, were tested on a hip simulator for an additional 2 million cycles using a modified ISO 14242 load waveform. In this context, a new approach was proposed in order to simulate, on a hip joint simulator, high-demand activities. In addition, the effects of these activities were analyzed in terms of wear and deformations of those polyethylenes by means of gravimetric method and micro X-ray computed tomography. In particular, while the gravimetric method was used for weight loss assessment, microcomputed tomography allowed for acquisition of additional quantitative information about the evolution of local wear and deformation through three-dimensional surface deviation maps for the entire cups’ surface. Experimental results showed that the wear and deformation behavior of these materials change according to different mechanical simulations. PMID:28772616

Effect of piezocision on root resorption associated with orthodontic force: A microcomputed tomography study.

PubMed

Patterson, Braydon M; Dalci, Oyku; Papadopoulou, Alexandra K; Madukuri, Suman; Mahon, Jonathan; Petocz, Peter; Spahr, Axel; Darendeliler, M Ali

2017-01-01

The purpose of this study was to investigate the effect of piezocision on orthodontically induced inflammatory root resorption. Fourteen patients were included in this split-mouth study; 1 side was assigned to piezocision, and the other side served as the control. Vertical corticotomy cuts of 4 to 5 mm in length were performed on either side of each piezocision premolar, and 150-g buccal tipping forces were applied to the premolars. After 4 weeks, the maxillary first premolars were extracted and scanned with microcomputed tomography. There was a significantly greater total amount of root resorption seen on the piezocision sides when compared with the control sides (P = 0.029). The piezocision procedure resulted in a 44% average increase in root resorption. In 5 patients, there was noticeable piezocision-related iatrogenic root damage. When that was combined with the orthodontic root resorption found on the piezocision-treated teeth, there was a statistically significant 110% average increase in volumetric root loss when compared with the control side (P = 0.005). The piezocision procedure that initiates the regional acceleratory phenomenon may increase the iatrogenic root resorption when used in conjunction with orthodontic forces. Piezocision applied close to the roots may cause iatrogenic damage to the neighboring roots and should be used carefully. Copyright © 2017.

Microcomputed tomography characterization of neovascularization in bone tissue engineering applications.

PubMed

Young, Simon; Kretlow, James D; Nguyen, Charles; Bashoura, Alex G; Baggett, L Scott; Jansen, John A; Wong, Mark; Mikos, Antonios G

2008-09-01

Vasculogenesis and angiogenesis have been studied for decades using numerous in vitro and in vivo systems, fulfilling the need to elucidate the mechanisms involved in these processes and to test potential therapeutic agents that inhibit or promote neovascularization. Bone tissue engineering in particular has benefited from the application of proangiogenic strategies, considering the need for an adequate vascular supply during healing and the challenges associated with the vascularization of scaffolds implanted in vivo. Conventional methods of assessing the in vivo angiogenic response to tissue-engineered constructs tend to rely on a two-dimensional assessment of microvessel density within representative histological sections without elaboration of the true vascular tree. The introduction of microcomputed tomography (micro-CT) has recently allowed investigators to obtain a diverse range of high-resolution, three-dimensional characterization of structures, including renal, coronary, and hepatic vascular networks, as well as bone formation within healing defects. To date, few studies have utilized micro-CT to study the vascular response to an implanted tissue engineering scaffold. In this paper, conventional in vitro and in vivo models for studying angiogenesis will be discussed, followed by recent developments in the use of micro-CT for vessel imaging in bone tissue engineering research. A new study demonstrating the potential of contrast-enhanced micro-CT for the evaluation of in vivo neovascularization in bony defects is described, which offers significant potential in the evaluation of bone tissue engineering constructs.

Effect of low-intensity pulsed ultrasound stimulation on gap healing in a rabbit osteotomy model evaluated by quantitative micro-computed tomography-based cross-sectional moment of inertia.

PubMed

Tobita, Kenji; Matsumoto, Takuya; Ohashi, Satoru; Bessho, Masahiko; Kaneko, Masako; Ohnishi, Isao

2012-07-01

It has been previously demonstrated that low-intensity pulsed ultrasound stimulation (LIPUS) enhances formation of the medullary canal and cortex in a gap-healing model of the tibia in rabbits, shortens the time required for remodeling, and enhances mineralization of the callus. In the current study, the mechanical integrity of these models was confirmed. In order to do this, the cross-sectional moment of inertia (CSMI) obtained from quantitative micro-computed tomography scans was calculated, and a comparison was made with a four-point bending test. This parameter can be analyzed in any direction, and three directions were selected in order to adopt an XYZ coordinate (X and Y for bending; Z for torsion). The present results demonstrated that LIPUS improved earlier restoration of bending stiffness at the healing site. In addition, LIPUS was effective not only in the ultrasound-irradiated plane, but also in the other two planes. CSMI may provide the structural as well as compositional determinants to assess fracture healing and would be very useful to replace the mechanical testing.

Contrast Agents for Micro-Computed Tomography of Microdamage in Bone

DTIC Science & Technology

2011-01-01

solution from DI water (or PBS). For the second model, a 5 mm cube of cortical bone tissue was embedded in polymethylmethacrylate and sectioned...radiography1 and as a radiopacifer in polymethylmethacrylate bone cement.2 Current commercial products for either application use microscale BaSO4 particles... polymethylmethacrylate bone cement (Lewis, 1997). The objective of this study was to non-destructively and three-dimensionally image microdamage

Micro-computed tomography and histomorphometric analysis of the effects of platelet-rich fibrin on bone regeneration in the rabbit calvarium.

PubMed

Acar, Ahmet Hüseyin; Yolcu, Ümit; Gül, Mehmet; Keleş, Ali; Erdem, Necip Fazıl; Altundag Kahraman, Sevil

2015-04-01

The present study aimed to investigate the effectiveness of platelet-rich fibrin (PRF) on bone regeneration when used alone or in combination with hydroxyapatite (HA)/beta-tricalcium phosphate (βTCP). In this study, 20 New Zealand white rabbits were used and four calvarial defects were prepared in each animal. PRF, Straumann(®) Bone Ceramic (SBC), or PRF+SBC was applied to the defects; one defect was left untreated as a control. Ten rabbits were sacrificed at week 4 (T1) and 10 at week 8 (T2). After micro-computed tomography (micro-CT) scanning, the samples were sent for histological and histomorphometric analysis to evaluate and compare the volume and area of regenerated bone. Histomorphometric and micro-CT analysis showed that both PRF and SBC significantly increased bone regeneration at T1 and T2 (P<0.01). When PRF was used in combination with HA/βTCP, a further significant increase in new bone formation was observed at T1 and T2 compared with that when PRF or SBC was used alone (P<0.01). PRF has a positive effect on bone formation when used alone and in combination with HA/βTCP. Copyright © 2014 Elsevier Ltd. All rights reserved.

Three-dimensional evaluation of effectiveness of hand and rotary instrumentation for retreatment of canals filled with different materials.

PubMed

Hammad, Mohammad; Qualtrough, Alison; Silikas, Nick

2008-11-01

The aim of this study was to measure the remaining filling volume of different obturation materials from root-filled extracted teeth by using 2 removal techniques. Eighty single-rooted teeth were collected and decoronated, and the root canal was prepared by using the ProTaper nickel-titanium rotary files. The teeth were randomly allocated into 4 groups, and each group was obturated by using a different material. Group 1 was filled with gutta-percha and TubliSeal sealer, group 2 was filled with EndoRez points and EndoRez sealer, group 3 was filled with RealSeal points and RealSeal sealer, and Group 4 was filled with a gutta-percha point and GuttaFlow sealer. Teeth were scanned with a micro-computed tomography scan, and then root fillings were removed by using ProTaper retreatment files or hand K-files. Teeth were scanned again, and volume measurements were carried out with micro-computed tomography software. Statistical analysis showed significant differences between the 2 removal techniques for gutta-percha and for both techniques between gutta-percha and the other groups. The present study showed that all tested filling materials were not completely removed during retreatment by using hand or rotary files. Gutta-percha was more efficiently removed by using hand K-files.

The Effect of Different Bone Marrow Stimulation Techniques on Human Talar Subchondral Bone: A Micro-Computed Tomography Evaluation.

PubMed

Gianakos, Arianna L; Yasui, Youichi; Fraser, Ethan J; Ross, Keir A; Prado, Marcelo P; Fortier, Lisa A; Kennedy, John G

2016-10-01

To evaluate morphological alterations, microarchitectural disturbances, and the extent of bone marrow access to the subchondral bone marrow compartment using micro-computed tomography analysis in different bone marrow stimulation (BMS) techniques. Nine zones in a 3 × 3 grid pattern were assigned to 5 cadaveric talar dome articular surfaces. A 1.00-mm microfracture awl (s.MFX), a 2.00-mm standard microfracture awl (l.MFX), or a 1.25-mm Kirschner wire (K-wire) drill hole was used to penetrate the subchondral bone in each grid zone. Subchondral bone holes and adjacent tissue areas were assessed by micro-computed tomography to analyze adjacent bone area destruction and communicating channels to the bone marrow. Grades 1 to 3 were assigned, where 1 = minimal compression/sclerosis; 2 = moderate compression/sclerosis; 3 = severe compression/sclerosis. Bone volume/total tissue volume, bone surface area/bone volume, trabecular thickness, and trabecular number were calculated in the region of interest. Visual assessment revealed that the s.MFX had significantly more grade 1 holes (P < .001) and that the l.MFX had significantly more poor/grade 3 holes (P = .002). Bone marrow channel assessment showed a statistically significant increase in the number of channels in the s.MFX when compared with both K-wire and l.MFX holes (P < .001). Bone volume fraction for the s.MFX was significantly less than that of the l.MFX (P = .029). BMS techniques using instruments with larger diameters resulted in increased trabecular compaction and sclerosis in areas adjacent to the defect. K-wire and l.MFX techniques resulted in less open communicating bone marrow channels, denoting a reduction in bone marrow access. The results of this study indicate that BMS using larger diameter devices results in greater microarchitecture disturbances. The current study suggests that the choice of a BMS technique should be carefully considered as the results indicate that smaller diameter hole sizes may diminish the amount of microarchitectural disturbances in the subchondral bone. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Peri-implant osseointegration after low-level laser therapy: micro-computed tomography and resonance frequency analysis in an animal model.

PubMed

Mayer, Luciano; Gomes, Fernando Vacilotto; de Oliveira, Marília Gerhardt; de Moraes, João Feliz Duarte; Carlsson, Lennart

2016-12-01

The purpose of the present study is to evaluate the effects of low-level laser therapy on the osseointegration process by comparing resonance frequency analysis measurements performed at implant placement and after 30 days and micro-computed tomography images in irradiated vs nonirradiated rabbits. Fourteen male New Zealand rabbits were randomly divided into two groups of seven animals each, one control group (nonirradiated animals) and one experimental group that received low-level laser therapy (Thera Lase®, aluminum-gallium-arsenide laser diode, 10 J per spot, two spots per session, seven sessions, 830 nm, 50 mW, CW, Ø 0.0028 cm 2 ). The mandibular left incisor was surgically extracted in all animals, and one osseointegrated implant was placed immediately afterward (3.25ø × 11.5 mm; NanoTite, BIOMET 3i). Resonance frequency analysis was performed with the Osstell® device at implant placement and at 30 days (immediately before euthanasia). Micro-computed tomography analyses were then conducted using a high-resolution scanner (SkyScan 1172 X-ray Micro-CT) to evaluate the amount of newly formed bone around the implants. Irradiated animals showed significantly higher implant stability quotients at 30 days (64.286 ± 1.596; 95 % confidence interval (CI) 60.808-67.764) than controls (56.357 ± 1.596; 95 %CI 52.879-59.835) (P = .000). The percentage of newly formed bone around the implants was also significantly higher in irradiated animals (75.523 ± 8.510; 95 %CI 61.893-89.155) than in controls (55.012 ± 19.840; 95 %CI 41.380-68.643) (P = .027). Laser therapy, based on the irradiation protocol used in this study, was able to provide greater implant stability and increase the volume of peri-implant newly formed bone, indicating that laser irradiation effected an improvement in the osseointegration process.

Investigation of hindwing folding in ladybird beetles by artificial elytron transplantation and microcomputed tomography.

PubMed

Saito, Kazuya; Nomura, Shuhei; Yamamoto, Shuhei; Niiyama, Ryuma; Okabe, Yoji

2017-05-30

Ladybird beetles are high-mobility insects and explore broad areas by switching between walking and flying. Their excellent wing transformation systems enabling this lifestyle are expected to provide large potential for engineering applications. However, the mechanism behind the folding of their hindwings remains unclear. The reason is that ladybird beetles close the elytra ahead of wing folding, preventing the observation of detailed processes occurring under the elytra. In the present study, artificial transparent elytra were transplanted on living ladybird beetles, thereby enabling us to observe the detailed wing-folding processes. The result revealed that in addition to the abdominal movements mentioned in previous studies, the edge and ventral surface of the elytra, as well as characteristic shaped veins, play important roles in wing folding. The structures of the wing frames enabling this folding process and detailed 3D shape of the hindwing were investigated using microcomputed tomography. The results showed that the tape spring-like elastic frame plays an important role in the wing transformation mechanism. Compared with other beetles, hindwings in ladybird beetles are characterized by two seemingly incompatible properties: ( i ) the wing rigidity with relatively thick veins and ( ii ) the compactness in stored shapes with complex crease patterns. The detailed wing-folding process revealed in this study is expected to facilitate understanding of the naturally optimized system in this excellent deployable structure.

Investigation of hindwing folding in ladybird beetles by artificial elytron transplantation and microcomputed tomography

PubMed Central

Nomura, Shuhei; Yamamoto, Shuhei; Niiyama, Ryuma; Okabe, Yoji

2017-01-01

Ladybird beetles are high-mobility insects and explore broad areas by switching between walking and flying. Their excellent wing transformation systems enabling this lifestyle are expected to provide large potential for engineering applications. However, the mechanism behind the folding of their hindwings remains unclear. The reason is that ladybird beetles close the elytra ahead of wing folding, preventing the observation of detailed processes occurring under the elytra. In the present study, artificial transparent elytra were transplanted on living ladybird beetles, thereby enabling us to observe the detailed wing-folding processes. The result revealed that in addition to the abdominal movements mentioned in previous studies, the edge and ventral surface of the elytra, as well as characteristic shaped veins, play important roles in wing folding. The structures of the wing frames enabling this folding process and detailed 3D shape of the hindwing were investigated using microcomputed tomography. The results showed that the tape spring-like elastic frame plays an important role in the wing transformation mechanism. Compared with other beetles, hindwings in ladybird beetles are characterized by two seemingly incompatible properties: (i) the wing rigidity with relatively thick veins and (ii) the compactness in stored shapes with complex crease patterns. The detailed wing-folding process revealed in this study is expected to facilitate understanding of the naturally optimized system in this excellent deployable structure. PMID:28507159

Quantitative three-dimensional analysis of root canal curvature in maxillary first molars using micro-computed tomography.

PubMed

Lee, Jong-Ki; Ha, Byung-Hyun; Choi, Jeong-Ho; Heo, Seok-Mo; Perinpanayagam, Hiran

2006-10-01

In endodontic therapy, access and instrumentation are strongly affected by root canal curvature. However, the few studies that have actually measured curvature are mostly from two-dimensional radiographs. The purpose of this study was to measure the three-dimensional (3D) canal curvature in maxillary first molars using micro-computed tomography (microCT) and mathematical modeling. Extracted maxillary first molars (46) were scanned by microCT (502 image slices/tooth, 1024 X 1024 pixels, voxel size of 19.5 x 19.5 x 39.0 microm) and their canals reconstructed by 3D modeling software. The intersection of major and minor axes in the canal space of each image slice were connected to create an imaginary central axis for each canal. The radius of curvature of the tangential circle was measured and inverted as a measure of curvature using custom-made mathematical modeling software. Root canal curvature was greatest in the apical third and least in the middle third for all canals. The greatest curvatures were in the mesiobuccal (MB) canal (0.76 +/- 0.48 mm(-1)) with abrupt curves, and the least curvatures were in the palatal (P) canal (0.38 +/- 0.34 mm(-1)) with a gradual curve. This study has measured the 3D curvature of root canals in maxillary first molars and reinforced the value of microCT with mathematical modeling.

Microcomputed Tomography Characterization of Neovascularization in Bone Tissue Engineering Applications

PubMed Central

Young, Simon; Kretlow, James D.; Nguyen, Charles; Bashoura, Alex G.; Baggett, L. Scott; Jansen, John A.; Wong, Mark

2008-01-01

Abstract Vasculogenesis and angiogenesis have been studied for decades using numerous in vitro and in vivo systems, fulfilling the need to elucidate the mechanisms involved in these processes and to test potential therapeutic agents that inhibit or promote neovascularization. Bone tissue engineering in particular has benefited from the application of proangiogenic strategies, considering the need for an adequate vascular supply during healing and the challenges associated with the vascularization of scaffolds implanted in vivo. Conventional methods of assessing the in vivo angiogenic response to tissue-engineered constructs tend to rely on a two-dimensional assessment of microvessel density within representative histological sections without elaboration of the true vascular tree. The introduction of microcomputed tomography (micro-CT) has recently allowed investigators to obtain a diverse range of high-resolution, three-dimensional characterization of structures, including renal, coronary, and hepatic vascular networks, as well as bone formation within healing defects. To date, few studies have utilized micro-CT to study the vascular response to an implanted tissue engineering scaffold. In this paper, conventional in vitro and in vivo models for studying angiogenesis will be discussed, followed by recent developments in the use of micro-CT for vessel imaging in bone tissue engineering research. A new study demonstrating the potential of contrast-enhanced micro-CT for the evaluation of in vivo neovascularization in bony defects is described, which offers significant potential in the evaluation of bone tissue engineering constructs. PMID:18657028

Detection of mouse liver cancer via a parallel iterative shrinkage method in hybrid optical/microcomputed tomography imaging

NASA Astrophysics Data System (ADS)

Wu, Ping; Liu, Kai; Zhang, Qian; Xue, Zhenwen; Li, Yongbao; Ning, Nannan; Yang, Xin; Li, Xingde; Tian, Jie

2012-12-01

Liver cancer is one of the most common malignant tumors worldwide. In order to enable the noninvasive detection of small liver tumors in mice, we present a parallel iterative shrinkage (PIS) algorithm for dual-modality tomography. It takes advantage of microcomputed tomography and multiview bioluminescence imaging, providing anatomical structure and bioluminescence intensity information to reconstruct the size and location of tumors. By incorporating prior knowledge of signal sparsity, we associate some mathematical strategies including specific smooth convex approximation, an iterative shrinkage operator, and affine subspace with the PIS method, which guarantees the accuracy, efficiency, and reliability for three-dimensional reconstruction. Then an in vivo experiment on the bead-implanted mouse has been performed to validate the feasibility of this method. The findings indicate that a tiny lesion less than 3 mm in diameter can be localized with a position bias no more than 1 mm the computational efficiency is one to three orders of magnitude faster than the existing algorithms; this approach is robust to the different regularization parameters and the lp norms. Finally, we have applied this algorithm to another in vivo experiment on an HCCLM3 orthotopic xenograft mouse model, which suggests the PIS method holds the promise for practical applications of whole-body cancer detection.

Application of X-ray microcomputed tomography in the characterization of irradiated nuclear fuel and material specimens

DOE PAGES

Silva, Chinthaka M.; Snead, Lance Lewis; Hunn, John D.; ...

2015-08-03

X-ray microcomputed tomography (µCT) was applied in characterizing the internal structures of a number of irradiated materials, including carbon-carbon fibre composites, nuclear-grade graphite and tristructural isotropic-coated fuel particles. Local cracks in carbon-carbon fibre composites associated with their synthesis process were observed with µCT without any destructive sample preparation. Pore analysis of graphite samples was performed quantitatively, and qualitative analysis of pore distribution was accomplished. It was also shown that high-resolution µCT can be used to probe internal layer defects of tristructural isotropic-coated fuel particles to elucidate the resulting high release of radioisotopes. Layer defects of sizes ranging from 1 tomore » 5 µm and up could be isolated by to-mography. As an added advantage, µCT could also be used to identify regions with high densities of radioisotopes to deter-mine the proper plane and orientation of particle mounting for further analytical characterization, such as materialographic sectioning followed by optical and electron microscopy. Lastly, in fully ceramic matrix fuel forms, despite the highly absorbing matrix, characterization of tristructural isotropic-coated particles embedded in a silicon carbide matrix was accomplished usingµCT and related advanced image analysis techniques.« less

Differential diagnosis of an unusual shoulder articular lesion in an ancient domestic dog (Canis lupus familiaris L., 1758).

PubMed

Lawler, D F; Rubin, D A; Evans, R H; Hildebolt, C F; Smith, K E; Widga, C; Martin, T J; Siegel, M; Sackman, J E; Smith, G K; Patel, T K

2013-12-01

A proximal humeral articular surface from an ancient domestic dog deliberate burial was examined during survey of small mammal bones from a prehistoric early Late Woodland archeological site. An unusual lesion on the caudolateral articular surface prompted micro-computed tomography to define detailed structure. Results indicate cortical or immature woven bone arising subchondrally, replacing normal trabeculae, extending through a breach in the cortical surface, and having sharp transition with surrounding normal bone. Organized bone within the lesion indicates that the dog lived for months-to-years following insult. Differential diagnoses initially included: sharp penetrating trauma; intrinsic or extrinsic blunt fracturing force; osteochondrosis or complication of an osteochondral lesion; unusual osteoarthritis; and neoplasia. Computed tomography ruled out normal or unusual osteoarthritis, and neoplasia. The nature and small size of the lesion, relatively small size of the dog, and lack of evidence for complicating infection, suggest against sharp penetrating trauma as a sole cause. The most plausible differential diagnoses include: uncommon fracture-producing force in a companion animal, and blunt intrinsic or extrinsic force causing fracture at a weak point, such as an early osteochondral lesion, that was obliterated by healing. Combined gross examination, micro-computed tomography, and archeological-anthropological influences facilitated refinement of differential diagnosis. Copyright © 2013 Elsevier Inc. All rights reserved.

Use of Micro-CT and Precision Cutting to Assess Meteorite Heterogeneity: An Example Using Brachinite NWA 4872

NASA Astrophysics Data System (ADS)

Hyde, B. C.; Tait, K. T.; Nicklin, I.; Day, J. M. D.; Ash, R. D.; Moser, D. E.

2013-09-01

Sectioning of meteorites is usually done in an arbitrary manner. We used micro-computed tomography to view the interior of brachinite NWA 4872. A cut was then made through an area of interest. Heterogeneity and modal abundance are discussed.

Non-invasive three-dimensional imaging of Escherichia coli K1 infection using diffuse light imaging tomography combined with micro-computed tomography.

PubMed

Witcomb, Luci A; Czupryna, Julie; Francis, Kevin P; Frankel, Gad; Taylor, Peter W

2017-08-15

In contrast to two-dimensional bioluminescence imaging, three dimensional diffuse light imaging tomography with integrated micro-computed tomography (DLIT-μCT) has the potential to realise spatial variations in infection patterns when imaging experimental animals dosed with derivatives of virulent bacteria carrying bioluminescent reporter genes such as the lux operon from the bacterium Photorhabdus luminescens. The method provides an opportunity to precisely localise the bacterial infection sites within the animal and enables the generation of four-dimensional movies of the infection cycle. Here, we describe the use of the PerkinElmer IVIS SpectrumCT in vivo imaging system to investigate progression of lethal systemic infection in neonatal rats following colonisation of the gastrointestinal tract with the neonatal pathogen Escherichia coli K1. We confirm previous observations that these bacteria stably colonize the colon and small intestine following feeding of the infectious dose from a micropipette; invading bacteria migrate across the gut epithelium into the blood circulation and establish foci of infection in major organs, including the brain. DLIT-μCT revealed novel multiple sites of colonisation within the alimentary canal, including the tongue, oesophagus and stomach, with penetration of the non-keratinised oesophageal epithelial surface, providing strong evidence of a further major site for bacterial dissemination. We highlight technical issues associated with imaging of infections in new born rat pups and show that the whole-body and organ bioburden correlates with disease severity. Copyright © 2017 Elsevier Inc. All rights reserved.

Geometric analysis of maxillary first premolar prepared by two nickel-titanium rotary instruments.

PubMed

Al-Sudani, Dina; Almalki, Majed; Al-Shahrani, Saad; Ahlquist, Michael

2014-03-01

The present study was conducted with the aim of evaluating and comparing the shaping ability of two Nickel-titanium rotary instruments, with two disparate design features, on root canal geometry of extracted human maxillary first premolars using microcomputed tomography. Twenty four bifurcated maxillary first premolars were divided into two groups and embedded in a rubber-based impression material. Both groups were submitted to micro-computed tomography before and after canal preparation (buccal and palatal) with either ProFile Vortex or Revo-S rotary instruments. Images were reconstructed and cross-sections corresponding to a distance 1, 2, 3, 4, 5, 6, and 7 mm from the anatomical apex were selected for canal transportation analysis. Volume changes were also measured. The degree and direction of canal transportation were non-significant for both instruments. Statistically significant differences were observed only between levels in the buccal canal in both groups. There was no significant difference between the two rotary systems in regards to the volume of dentin removed. Our findings showed that ProFile Vortex and Revo-S instruments respected the original root canal anatomy and behaved similarly. ProFile Vortex rotary systems produced with innovative process were concluded to shape the upper maxillary premolar by leading minimal canal transportation, similar to Revo-S, rotary systems produced from traditional process.

Chitin-fibroin-hydroxyapatite membrane for guided bone regeneration: micro-computed tomography evaluation in a rat model.

PubMed

Baek, Young-Jae; Kim, Jung-Han; Song, Jae-Min; Yoon, Sang-Yong; Kim, Hong-Sung; Shin, Sang-Hun

2016-12-01

In guided bone regeneration (GBR) technique, many materials have been used for improving biological effectiveness by adding on membranes. The new membrane which was constructed with chitin-fibroin-hydroxyapatite (CNF/HAP) was compared with a collagen membrane (Bio-Gide®) by means of micro-computed tomography. Fifty-four rats were used in this study. A critical-sized (8 mm) bony defect was created in the calvaria with a trephine bur. The CNF/HAP membrane was prepared by thermally induced phase separation. In the experimental group ( n  = 18), the CNF/HAP membrane was used to cover the bony defect, and in the control group ( n  = 18), a resorbable collagen membrane (Bio-Gide®) was used. In the negative control group ( n  = 18), no membrane was used. In each group, six animals were euthanized at 2, 4, and 8 weeks after surgery. The specimens were analyzed using micro-CT. Bone volume (BV) and bone mineral density (BMD) of the new bone showed significant difference between the negative control group and membrane groups ( P  < 0.05). However, between two membranes, the difference was not significant. The CNF/HAP membrane has significant effect on the new bone formation and has the potential to be applied for guided bone regeneration.

Comparison of digital intraoral scanners by single-image capture system and full-color movie system.

PubMed

Yamamoto, Meguru; Kataoka, Yu; Manabe, Atsufumi

2017-01-01

The use of dental computer-aided design/computer-aided manufacturing (CAD/CAM) restoration is rapidly increasing. This study was performed to evaluate the marginal and internal cement thickness and the adhesive gap of internal cavities comprising CAD/CAM materials using two digital impression acquisition methods and micro-computed tomography. Images obtained by a single-image acquisition system (Bluecam Ver. 4.0) and a full-color video acquisition system (Omnicam Ver. 4.2) were divided into the BL and OM groups, respectively. Silicone impressions were prepared from an ISO-standard metal mold, and CEREC Stone BC and New Fuji Rock IMP were used to create working models (n=20) in the BL and OM groups (n=10 per group), respectively. Individual inlays were designed in a conventional manner using designated software, and all restorations were prepared using CEREC inLab MC XL. These were assembled with the corresponding working models used for measurement, and the level of fit was examined by three-dimensional analysis based on micro-computed tomography. Significant differences in the marginal and internal cement thickness and adhesive gap spacing were found between the OM and BL groups. The full-color movie capture system appears to be a more optimal restoration system than the single-image capture system.

Micro-computed tomography visualization of the vestigial alimentary canal in adult oestrid flies.

PubMed

Martín-Vega, D; Garbout, A; Ahmed, F; Ferrer, L M; Lucientes, J; Colwell, D D; Hall, M J R

2018-02-16

Oestrid flies (Diptera: Oestridae) do not feed during the adult stage as they acquire all necessary nutrients during the parasitic larval stage. The adult mouthparts and digestive tract are therefore frequently vestigial; however, morphological data on the alimentary canal in adult oestrid flies are scarce and a proper visualization of this organ system within the adult body is lacking. The present work visualizes the morphology of the alimentary canal in adults of two oestrid species, Oestrus ovis L. and Hypoderma lineatum (de Villiers), with the use of non-invasive micro-computed tomography (micro-CT) and compares it with the highly developed alimentary canal of the blow fly Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae). Both O. ovis and H. lineatum adults showed significant reductions of the cardia and the diameter of the digestive tract, an absence of the helicoidal portion of the midgut typical of other cyclorrhaphous flies, and a lack of crop and salivary glands. Given the current interest in the alimentary canal in adult dipterans in biomedical and developmental biology studies, further understanding of the morphology and development of this organ system in adult oestrids may provide valuable new insights in several areas of research. © 2018 The Royal Entomological Society.

Synthesis of nanostructured barium phosphate and its application in micro-computed tomography of mouse brain vessels in ex vivo

NASA Astrophysics Data System (ADS)

Zhu, Bangshang; Yuan, Falei; Yuan, Xiaoya; Bo, Yang; Wang, Yongting; Yang, Guo-Yuan; Drummen, Gregor P. C.; Zhu, Xinyuan

2014-02-01

Micro-computed tomography (micro-CT) is a powerful tool for visualizing the vascular systems of tissues, organs, or entire small animals. Vascular contrast agents play a vital role in micro-CT imaging in order to obtain clear and high-quality images. In this study, a new kind of nanostructured barium phosphate was fabricated and used as a contrast agent for ex vivo micro-CT imaging of blood vessels in the mouse brain. Nanostructured barium phosphate was synthesized through a simple wet precipitation method using Ba(NO3)2, and (NH4)2HPO4 as starting materials. The physiochemical properties of barium phosphate were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and thermal analysis. Furthermore, the impact of the produced nanostructures on cell viability was evaluated via the MTT assay, which generally showed low to moderate cytotoxicity. Finally, the animal test images demonstrated that the use of nanostructured barium phosphate as a contrast agent in Micro-CT imaging produced sharp images with excellent contrast. Both major vessels and the microvasculature were clearly observable in the imaged mouse brain. Overall, the results indicate that nanostructured barium phosphate is a potential and useful vascular contrast agent for micro-CT imaging.

Construction of three-dimensional tooth model by micro-computed tomography and application for data sharing.

PubMed

Kato, A; Ohno, N

2009-03-01

The study of dental morphology is essential in terms of phylogeny. Advances in three-dimensional (3D) measurement devices have enabled us to make 3D images of teeth without destruction of samples. However, raw fundamental data on tooth shape requires complex equipment and techniques. An online database of 3D teeth models is therefore indispensable. We aimed to explore the basic methodology for constructing 3D teeth models, with application for data sharing. Geometric information on the human permanent upper left incisor was obtained using micro-computed tomography (micro-CT). Enamel, dentine, and pulp were segmented by thresholding of different gray-scale intensities. Segmented data were separately exported in STereo-Lithography Interface Format (STL). STL data were converted to Wavefront OBJ (OBJect), as many 3D computer graphics programs support the Wavefront OBJ format. Data were also applied to Quick Time Virtual Reality (QTVR) format, which allows the image to be viewed from any direction. In addition to Wavefront OBJ and QTVR data, the original CT series were provided as 16-bit Tag Image File Format (TIFF) images on the website. In conclusion, 3D teeth models were constructed in general-purpose data formats, using micro-CT and commercially available programs. Teeth models that can be used widely would benefit all those who study dental morphology.

Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation.

PubMed

Kang, Sung-Won; Lee, Woo-Jin; Choi, Soon-Chul; Lee, Sam-Sun; Heo, Min-Suk; Huh, Kyung-Hoe; Kim, Tae-Il; Yi, Won-Jin

2015-03-01

We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.

Forensic microradiology: micro-computed tomography (Micro-CT) and analysis of patterned injuries inside of bone.

PubMed

Thali, Michael J; Taubenreuther, Ulrike; Karolczak, Marek; Braun, Marcel; Brueschweiler, Walter; Kalender, Willi A; Dirnhofer, Richard

2003-11-01

When a knife is stabbed in bone, it leaves an impression in the bone. The characteristics (shape, size, etc.) may indicate the type of tool used to produce the patterned injury in bone. Until now it has been impossible in forensic sciences to document such damage precisely and non-destructively. Micro-computed tomography (Micro-CT) offers an opportunity to analyze patterned injuries of tool marks made in bone. Using high-resolution Micro-CT and computer software, detailed analysis of three-dimensional (3D) architecture has recently become feasible and allows microstructural 3D bone information to be collected. With adequate viewing software, data from 2D slice of an arbitrary plane can be extracted from 3D datasets. Using such software as a "digital virtual knife," the examiner can interactively section and analyze the 3D sample. Analysis of the bone injury revealed that Micro-CT provides an opportunity to correlate a bone injury to an injury-causing instrument. Even broken knife tips can be graphically and non-destructively assigned to a suspect weapon.

Mathematical filtering minimizes metallic halation of titanium implants in MicroCT images.

PubMed

Ha, Jee; Osher, Stanley J; Nishimura, Ichiro

2013-01-01

Microcomputed tomography (MicroCT) images containing titanium implant suffer from x-rays scattering, artifact and the implant surface is critically affected by metallic halation. To improve the metallic halation artifact, a nonlinear Total Variation denoising algorithm such as Split Bregman algorithm was applied to the digital data set of MicroCT images. This study demonstrated that the use of a mathematical filter could successfully reduce metallic halation, facilitating the osseointegration evaluation at the bone implant interface in the reconstructed images.

Nucleation and growth of chimney pores during electron-beam additive manufacturing

DOE PAGES

Cordero, Zachary C.; Dinwiddie, Ralph B.; Immel, David; ...

2016-12-05

The nucleation and growth of chimney pores during powder-bed, electron-beam additive manufacturing is investigated using in-situ infrared thermography as well as microcomputed tomography of as-printed parts. The pores are found to nucleate at dimples on the part s surface, clearly demonstrating how process parameters can affect surface roughness, which can in turn affect the internal defect structure in an additive manufactured part. Based on the results of this study, several strategies for suppressing the formation of chimney pores are discussed.

Virtual reconstruction of the skeletal labyrinth of two lamnid sharks (Elasmobranchii, Lamniformes).

PubMed

Schnetz, L; Kriwet, J; Pfaff, C

2017-03-01

The first virtual reconstruction of the skeletal labyrinth of the porbeagle shark Lamna nasus and the shortfin mako shark Isurus oxyrinchus is presented here using high-resolution micro-computed tomography. The results, in comparison with previously published information, suggest relationships between skeletal labyrinth morphology and locomotion mode in chondrichthyans, but also show that further studies are required to establish such connections. Nevertheless, this study adds to the knowledge of the skeletal labyrinth morphology in two apex elasmobranch species. © 2016 The Fisheries Society of the British Isles.

Three Dimensional Cancellous Bone Structure in Hypoparathyroidism

PubMed Central

Rubin, Mishaela R.; Dempster, David W.; Kohler, Thomas; Stauber, Martin; Zhou, Hua; Shane, Elizabeth; Nickolas, Thomas; Stein, Emily; Sliney, James; Silverberg, Shonni J.; Bilezikian, John P.; Müller, Ralph

2009-01-01

By conventional 2-dimensional histomorphometric analysis, we have shown that cancellous bone architecture is markedly altered in hypoparathyroidism. We have now extended these observations to a 3-dimensional analysis using microcomputed tomography. Percutaneous iliac crest bone biopsies were analyzed by high-resolution microcomputed tomography from the following 25 subjects with hypoparathyroidism: 5 postmenopausal women, 13 premenopausal women and 7 men. Thirteen living premenopausal healthy controls and 12 cadaver subjects without bone disease served as matched controls. Hypoparathyroid subjects had significantly greater bone surface density (BS/TV: 5.74 ± 4.7 vs. 3.73 ± 1.01 mm2/mm3 [mean ± SD]; p=0.04), trabecular thickness (Tb.Th: 0.25 ± 0.19 vs. 0.17 ± 0.04 mm; p=0.04), trabecular number (Tb.N: 2.99 ± 3.4 vs. 1.62 ± 0.39 mm−1; p=0.05) and connectivity density (Conn.D: 16.63 ± 18.7 vs. 8.39 ± 5.8 mm3; p=0.04) in comparison to matched controls. When an additional 8 hypoparathyorid (total n= 33) and 24 cadaver (total cadaver n= 36) subjects were added to the groups for an unmatched analysis, hypoparathyroid subjects had significantly greater cancellous bone volume (BV/TV: 26.98 ± 10 vs. 15.39 ± 4%; p< 0.001), , while trabecular separation (Tb.Sp: 0.642 ± 0.10 vs. 0.781 ± 0.13 mm; p<0.001) and estimation of the plate-rod characteristic (SMI: −0.457 ± 1.52 vs. 0.742 ± 0.51; p<0.001) were significantly lower, the latter observation implying a more plate-like trabecular structure. Variables of cancellous bone structure in the hypoparathyroid subjects, as assessed by microcomputed tomography, were highly correlated with those assessed by conventional histomorphometry. We conclude that cancellous bone in hypoparathyroidism is abnormal, suggesting that parathyroid hormone is required to maintain normal trabecular structure. The effect of these structural changes on bone strength remains to be determined. PMID:19782782

Potential Therapeutic Use of Relaxin in Healing Cranial Bone Defects

DTIC Science & Technology

2016-08-01

successful production of chimeric mice after irradiation and GFP+ bone marrow transplantation; reproducible implementation of uniform cranial lesions of ~1.5...cranial defect model in chimeric mice transplanted with GFP+ bone marrow. We follow defect closure by three dimensional microcomputed tomography (µCT...histolomorphometry and immunohistochemistry, respectively. 2. Keywords GFP+ chimeric mice, cranial defect closure, relaxin, angiogenesis

Using Micro-computed Tomography for the Assessment of Tumor Development and Follow-up of Response to Treatment in a Mouse Model of Lung Cancer.

PubMed

Hegab, Ahmed E; Kameyama, Naofumi; Kuroda, Aoi; Kagawa, Shizuko; Yin, Yongjun; Ornitz, David; Betsuyaku, Tomoko

2016-05-20

Lung cancer is the most lethal cancer in the world. Intensive research is ongoing worldwide to identify new therapies for lung cancer. Several mouse models of lung cancer are being used to study the mechanism of cancer development and to experiment with various therapeutic strategies. However, the absence of a real-time technique to identify the development of tumor nodules in mice lungs and to monitor the changes in their size in response to various experimental and therapeutic interventions hampers the ability to obtain an accurate description of the course of the disease and its timely response to treatments. In this study, a method using a micro-computed tomography (CT) scanner for the detection of the development of lung tumors in a mouse model of lung adenocarcinoma is described. Next, we show that monthly follow-up with micro-CT can identify dynamic changes in the lung tumor, such as the appearance of additional nodules, increase in the size of previously detected nodules, and decrease in the size or complete resolution of nodules in response to treatment. Finally, the accuracy of this real-time assessment method was confirmed with end-point histological quantification. This technique paves the way for planning and conducting more complex experiments on lung cancer animal models, and it enables us to better understand the mechanisms of carcinogenesis and the effects of different treatment modalities while saving time and resources.

Hepatic Osteodystrophy: The Mechanism of Bone Loss in Hepatocellular Disease and the Effects of Pamidronate Treatment

PubMed Central

Spirlandeli, Adriano L.; Dick-de-Paula, Ingrid; Zamarioli, Ariane; Jorgetti, Vanda; Ramalho, Leandra N.Z.; Nogueira-Barbosa, Marcello H.; Volpon, Jose B.; Jordão, Alceu A.; Cunha, Fernando Q.; Fukada, Sandra Y.; de Paula, Francisco J.A.

2017-01-01

OBJECTIVES: The present study was designed to evaluate the bone phenotypes and mechanisms involved in bone disorders associated with hepatic osteodystrophy. Hepatocellular disease was induced by carbon tetrachloride (CCl4). In addition, the effects of disodium pamidronate on bone tissue were evaluated. METHODS: The study included 4 groups of 15 mice: a) C = mice subjected to vehicle injections; b) C+P = mice subjected to vehicle and pamidronate injections; c) CCl4+V = mice subjected to CCl4 and vehicle injections; and d) CCl4+P = mice subjected to CCl4 and pamidronate injections. CCl4 or vehicle was administered for 8 weeks, while pamidronate or vehicle was injected at the end of the fourth week. Bone histomorphometry and biomechanical analysis were performed in tibiae, while femora were used for micro-computed tomography and gene expression. RESULTS: CCl4 mice exhibited decreased bone volume/trabecular volume and trabecular numbers, as well as increased trabecular separation, as determined by bone histomorphometry and micro-computed tomography, but these changes were not detected in the group treated with pamidronate. CCl4 mice showed increased numbers of osteoclasts and resorption surface. High serum levels of receptor activator of nuclear factor-κB ligand and the increased expression of tartrate-resistant acid phosphatase in the bones of CCl4 mice supported the enhancement of bone resorption in these mice. CONCLUSION: Taken together, these results suggest that bone resorption is the main mechanism of bone loss in chronic hepatocellular disease in mice. PMID:28492723

Hepatic Osteodystrophy: The Mechanism of Bone Loss in Hepatocellular Disease and the Effects of Pamidronate Treatment.

PubMed

Spirlandeli, Adriano L; Dick-de-Paula, Ingrid; Zamarioli, Ariane; Jorgetti, Vanda; Ramalho, Leandra N Z; Nogueira-Barbosa, Marcello H; Volpon, Jose B; Jordão, Alceu A; Cunha, Fernando Q; Fukada, Sandra Y; de Paula, Francisco J A

2017-04-01

The present study was designed to evaluate the bone phenotypes and mechanisms involved in bone disorders associated with hepatic osteodystrophy. Hepatocellular disease was induced by carbon tetrachloride (CCl4). In addition, the effects of disodium pamidronate on bone tissue were evaluated. The study included 4 groups of 15 mice: a) C = mice subjected to vehicle injections; b) C+P = mice subjected to vehicle and pamidronate injections; c) CCl4+V = mice subjected to CCl4 and vehicle injections; and d) CCl4+P = mice subjected to CCl4 and pamidronate injections. CCl4 or vehicle was administered for 8 weeks, while pamidronate or vehicle was injected at the end of the fourth week. Bone histomorphometry and biomechanical analysis were performed in tibiae, while femora were used for micro-computed tomography and gene expression. CCl4 mice exhibited decreased bone volume/trabecular volume and trabecular numbers, as well as increased trabecular separation, as determined by bone histomorphometry and micro-computed tomography, but these changes were not detected in the group treated with pamidronate. CCl4 mice showed increased numbers of osteoclasts and resorption surface. High serum levels of receptor activator of nuclear factor-κB ligand and the increased expression of tartrate-resistant acid phosphatase in the bones of CCl4 mice supported the enhancement of bone resorption in these mice. Taken together, these results suggest that bone resorption is the main mechanism of bone loss in chronic hepatocellular disease in mice.

Micro-computed tomography of false starts produced on bone by different hand-saws.

PubMed

Pelletti, Guido; Viel, Guido; Fais, Paolo; Viero, Alessia; Visentin, Sindi; Miotto, Diego; Montisci, Massimo; Cecchetto, Giovanni; Giraudo, Chiara

2017-05-01

The analysis of macro- and microscopic characteristics of saw marks on bones can provide useful information about the class of the tool utilized to produce the injury. The aim of the present study was to test micro-computed tomography (micro-CT) for the analysis of false starts experimentally produced on 32 human bone sections using 4 different hand-saws in order to verify the potential utility of micro-CT for distinguishing false starts produced by different saws and to correlate the morphology of the tool with that of the bone mark. Each sample was analysed through stereomicroscopy and micro-CT. Stereomicroscopic analysis allowed the identification of the false starts and the detection of the number of tool marks left by each saw. Micro-CT scans, through the integration of 3D renders and multiplanar reconstructions (MPR), allowed the identification of the shape of each false start correlating it to the injuring tool. Our results suggest that micro-CT could be a useful technique for assessing false starts produced by different classes of saws, providing accurate morphological profiles of the bone marks with all the advantages of high resolution 3D imaging (e.g., high accuracy, non-destructive analysis, preservation and documentation of evidence). However, further studies are necessary to integrate qualitative data with quantitative metrical analysis in order to further characterize the false start and the related injuring tool. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparative microcomputed tomography and histological study of maxillary pneumatization in four species of new world monkeys: the perinatal period.

PubMed

Smith, Timothy D; Rossie, James B; Cooper, Gregory M; Schmieg, Robin M; Bonar, Christopher J; Mooney, Mark P; Siegel, Michael I

2011-03-01

In anthropoid primates, it has been hypothesized that the magnitude of maxillary sinus growth is influenced by adjacent dental and soft tissue matrices. Relatively, little comparative evidence exists for the perinatal period when secondary pneumatization is at its earliest stages in some primates. Here, dental and midfacial variables were studied in a perinatal sample of four anthropoid primates, including three callitrichines (Leontopithecus, Saguinus, and Callithrix) and Saimiri boliviensis. In the latter species, the maxillary recess (the ontogenetic precursor to a "true" maxillary sinus) does not undergo secondary pneumatization. Using histological methods and micro-computed tomography, midfacial and dental dimensions and radiographic hydroxyapatite density of tooth cusps were measured. The distribution of osteoclasts and osteoblasts was also documented. Kruskal-Wallis's one-way analysis of variance tests indicates significant (P < 0.05) differences among groups for dental and midfacial measurements. In particular, the posterior maxillary dentition is relatively larger and more mineralized in Saimiri compared to the callitrichines. At posterior dental levels, Saimiri has the lowest palatonasal index [interdental (palatal) width/width of the nasal cavity] and highest bizygomatic-interorbital index. Distribution of osteoclasts indicates that the inferomedial surfaces of the orbits are resorptive in perinatal Saimiri, whereas, in all callitrichines, these surfaces are depository. Taken together, these findings suggest that pneumatization in Saimiri is suppressed by an inward growth trajectory of the orbits, relatively large posterior dentition, and a correspondingly compressed nasal region. Copyright © 2010 Wiley-Liss, Inc.

Micro-computed tomography characterization of tissue engineering scaffolds: effects of pixel size and rotation step.

PubMed

Cengiz, Ibrahim Fatih; Oliveira, Joaquim Miguel; Reis, Rui L

2017-08-01

Quantitative assessment of micro-structure of materials is of key importance in many fields including tissue engineering, biology, and dentistry. Micro-computed tomography (µ-CT) is an intensively used non-destructive technique. However, the acquisition parameters such as pixel size and rotation step may have significant effects on the obtained results. In this study, a set of tissue engineering scaffolds including examples of natural and synthetic polymers, and ceramics were analyzed. We comprehensively compared the quantitative results of µ-CT characterization using 15 acquisition scenarios that differ in the combination of the pixel size and rotation step. The results showed that the acquisition parameters could statistically significantly affect the quantified mean porosity, mean pore size, and mean wall thickness of the scaffolds. The effects are also practically important since the differences can be as high as 24% regarding the mean porosity in average, and 19.5 h and 166 GB regarding the characterization time and data storage per sample with a relatively small volume. This study showed in a quantitative manner the effects of such a wide range of acquisition scenarios on the final data, as well as the characterization time and data storage per sample. Herein, a clear picture of the effects of the pixel size and rotation step on the results is provided which can notably be useful to refine the practice of µ-CT characterization of scaffolds and economize the related resources.

Evaluation of in-vivo measurement errors associated with micro-computed tomography scans by means of the bone surface distance approach.

PubMed

Lu, Yongtao; Boudiffa, Maya; Dall'Ara, Enrico; Bellantuono, Ilaria; Viceconti, Marco

2015-11-01

In vivo micro-computed tomography (µCT) scanning is an important tool for longitudinal monitoring of the bone adaptation process in animal models. However, the errors associated with the usage of in vivo µCT measurements for the evaluation of bone adaptations remain unclear. The aim of this study was to evaluate the measurement errors using the bone surface distance approach. The right tibiae of eight 14-week-old C57BL/6 J female mice were consecutively scanned four times in an in vivo µCT scanner using a nominal isotropic image voxel size (10.4 µm) and the tibiae were repositioned between each scan. The repeated scan image datasets were aligned to the corresponding baseline (first) scan image dataset using rigid registration and a region of interest was selected in the proximal tibia metaphysis for analysis. The bone surface distances between the repeated and the baseline scan datasets were evaluated. It was found that the average (±standard deviation) median and 95th percentile bone surface distances were 3.10 ± 0.76 µm and 9.58 ± 1.70 µm, respectively. This study indicated that there were inevitable errors associated with the in vivo µCT measurements of bone microarchitecture and these errors should be taken into account for a better interpretation of bone adaptations measured with in vivo µCT. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

The microstructure of capsule containing self-healing materials: A micro-computed tomography study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Stappen, Jeroen, E-mail: Jeroen.Vanstappen@uge

Autonomic self-healing materials are materials with built-in (micro-) capsules or vessels, which upon fracturing release healing agents in order to recover the material's physical and mechanical properties. In order to better understand and engineer these materials, a thorough characterization of the material's microstructural behavior is essential and often overlooked. In this context, micro-computed tomography (μCT) can be used to investigate the three dimensional distribution and (de)bonding of (micro-) capsules in their native state in a polymer system with self-healing properties. Furthermore, in-situ μCT experiments in a self-healing polymer and a self-healing concrete system can elucidate the breakage and leakage behaviormore » of (micro-) capsules at the micrometer scale. While challenges related to image resolution and contrast complicate the characterization in specific cases, non-destructive 3D imaging with μCT is shown to contribute to the understanding of the link between the microstructure and the self-healing behavior of these complex materials. - Highlights: • μCT imaging allows for the analysis of microcapsule distribution patterns in self-healing materials. • μCT allows for qualitative and quantitative measurements of healing agent release from carriers in self-healing materials. • Experimental set-ups can be optimized by changing chemical compounds in the system to ensure maximum quality imaging.« less

Single versus triple daily activation of the distractor: no significant effects of frequency of distraction on bone regenerate quantity and architecture.

PubMed

Djasim, Urville Mardijanto; Wolvius, Eppo Bonne; Van Neck, Johan Wilhelm; Van Wamel, Annemieke; Weinans, Harrie; Van Der Wal, Karel George Hendrik

2008-04-01

To study the effect of two different frequencies of distraction on the quantity and architecture of bone regenerate using micro-computed tomography, and to determine whether radiographic and ultrasonographic bone-fill scores provide reliable predictive value for the amount of new bone in the distraction area. Twenty-six skeletally mature rabbits underwent three full days of latency, after which midface distraction was started. Low-frequency group (n=12): a distraction rate of 0.9 mm/d achieved by one daily activation for 11 days to create a 10mm distraction gap. High-frequency group (n=12): idem, but three daily activations were used instead of one. Control group (n=2) underwent no distraction. After 21 days of consolidation, bone-fill in the distraction area was assessed by means of ultrasonography and radiography. Micro-computed tomography was used to quantify new bone formation and bone architecture. Relative bone volume (BV/TV) showed a tendency towards a difference (P=0.09) between the low and high-frequency groups. No significant differences were found for bone architecture. No significant correlation between BV/TV values and bone-fill scores was found. An increase in rhythm from one to three activations daily does not create significantly more bone. Bone-fill score values provided no reliable predictive value for the amount of new bone formation.

The quantitative assessment of peri-implant bone responses using histomorphometry and micro-computed tomography.

PubMed

Schouten, Corinne; Meijer, Gert J; van den Beucken, Jeroen J J P; Spauwen, Paul H M; Jansen, John A

2009-09-01

In the present study, the effects of implant design and surface properties on peri-implant bone response were evaluated with both conventional histomorphometry and micro-computed tomography (micro-CT), using two geometrically different dental implants (Screw type, St; Push-in, Pi) either or not surface-modified (non-coated, CaP-coated, or CaP-coated+TGF-beta1). After 12 weeks of implantation in a goat femoral condyle model, peri-implant bone response was evaluated in three different zones (inner: 0-500 microm; middle: 500-1000 microm; and outer: 1000-1500 microm) around the implant. Results indicated superiority of conventional histomorphometry over micro-CT, as the latter is hampered by deficits in the discrimination at the implant/tissue interface. Beyond this interface, both analysis techniques can be regarded as complementary. Histomorphometrical analysis showed an overall higher bone volume around St compared to Pi implants, but no effects of surface modification were observed. St implants showed lowest bone volumes in the outer zone, whereas inner zones were lowest for Pi implants. These results implicate that for Pi implants bone formation started from two different directions (contact- and distance osteogenesis). For St implants it was concluded that undersized implantation technique and loosening of bone fragments compress the zones for contact and distant osteogenesis, thereby improving bone volume at the interface significantly.

Evaluation of fixation of expandable implants in the mandibles of ovariectomized sheep.

PubMed

Xiao, Jian-Rui; Li, De-Hua; Chen, Yu-Xuan; Chen, Shu-Jun; Guan, Su-Min; Kong, Liang

2013-04-01

This study aimed to investigate the effects of an expandable implant (EI) in ovariectomized sheep. The EI and taper implant (control group) were produced and placed in mandibles of ovariectomized sheep. Twelve weeks after implantation, resonance frequency analysis, biomechanical tests, histomorphometry, and micro-computed tomography were applied to detect the osseointegration in the 2 groups. The implant stability quotient values, maximal pullout forces, and bone-implant contact (BIC) were 60.3 ± 7.9, 511.0 ± 18.7 N, and 53.14% ± 4.56%, respectively, in the EI group and 58.3 ± 8.9, 394.5 ± 54.5 N, and 46.85% ± 5.04%, respectively, in the control group. There was no significant difference between the 2 groups in implant stability quotient values (P > .05); however, in the EI group the maximal pullout force and BIC were increased significantly (P < .05 and P < .01, respectively). Micro-computed tomography analysis showed that the bone volume/total volume ratio and trabecular number increased significantly (P < .01) and trabecular separation decreased significantly (P < .05) in the EI group. EI could improve osseointegration in osteoporosis after 12 weeks of implantation by increasing BIC around the implant and by supplying an extra osseointegration surface. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Influence of low-intensity pulsed ultrasound on osteogenic tissue regeneration in a periodontal injury model: X-ray image alterations assessed by micro-computed tomography.

PubMed

Wang, Yunji; Chai, Zhaowu; Zhang, Yuanyuan; Deng, Feng; Wang, Zhibiao; Song, Jinlin

2014-08-01

This study was conducted to evaluate, with micro-computed tomography, the influence of low-intensity pulsed ultrasound on wound-healing in periodontal tissues. Periodontal disease with Class II furcation involvement was surgically produced at the bilateral mandibular premolars in 8 adult male beagle dogs. Twenty-four teeth were randomly assigned among 4 groups (G): G1, periodontal flap surgery; G2, periodontal flap surgery+low-intensity pulsed ultrasound (LIPUS); G3, guided tissue regeneration (GTR) surgery; G4, GTR surgery plus LIPUS. The affected area in the experimental group was exposed to LIPUS. At 6 and 8weeks, the X-ray images of regenerated teeth were referred to micro-CT scanning for 3-D measurement. Bone volume (BV), bone surface (BS), and number of trabeculae (Tb) in G2 and G4 were higher than in G1 and G3 (p<0.05). BV, BS, and Tb.N of the GTR+LIPUS group were higher than in the GTR group. BV, BS, and Tb.N of the LIPUS group were higher than in the periodontal flap surgery group. LIPUS irradiation increased the number, volume, and area of new alveolar bone trabeculae. LIPUS has the potential to promote the repair of periodontal tissue, and may work effectively if combined with GTR. Copyright © 2014 Elsevier B.V. All rights reserved.

Root canal morphology of primary molars: a micro-computed tomography study.

PubMed

Fumes, A C; Sousa-Neto, M D; Leoni, G B; Versiani, M A; da Silva, L A B; da Silva, R A B; Consolaro, A

2014-10-01

This was to investigate the root canal morphology of primary molar teeth using micro-computed tomography. Primary maxillary (n = 20) and mandibular (n = 20) molars were scanned at a resolution of 16.7 μm and analysed regarding the number, location, volume, area, structured model index (SMI), area, roundness, diameters, and length of canals, as well as the thickness of dentine in the apical third. Data were statistically compared by using paired-sample t test, independent sample t test, and one-way analysis of variance with significance level set as 5%. Overall, no statistical differences were found between the canals with respect to length, SMI, dentine thickness, area, roundness, and diameter (p > 0.05). A double canal system was observed in the mesial and mesio-buccal roots of the mandibular and maxillary molars, respectively. The thickness in the internal aspect of the roots was lower than in the external aspect. Cross-sectional evaluation of the roots in the apical third showed flat-shaped canals in the mandibular molars and ribbon- and oval-shaped canals in the maxillary molars. External and internal anatomy of the primary first molars closely resemble the primary second molars. The reported data may help clinicians to obtain a thorough understanding of the morphological variations of root canals in primary molars to overcome problems related to shaping and cleaning procedures, allowing appropriate management strategies for root canal treatment.

Quantitative analysis of bone and soft tissue by micro-computed tomography: applications to ex vivo and in vivo studies

PubMed Central

Campbell, Graeme M; Sophocleous, Antonia

2014-01-01

Micro-computed tomography (micro-CT) is a high-resolution imaging modality that is capable of analysing bone structure with a voxel size on the order of 10 μm. With the development of in vivo micro-CT, where disease progression and treatment can be monitored in a living animal over a period of time, this modality has become a standard tool for preclinical assessment of bone architecture during disease progression and treatment. For meaningful comparison between micro-CT studies, it is essential that the same parameters for data acquisition and analysis methods be used. This protocol outlines the common procedures that are currently used for sample preparation, scanning, reconstruction and analysis in micro-CT studies. Scan and analysis methods for trabecular and cortical bone are covered for the femur, tibia, vertebra and the full neonate body of small rodents. The analysis procedures using the software provided by ScancoMedical and Bruker are discussed, and the routinely used bone architectural parameters are outlined. This protocol also provides a section dedicated to in vivo scanning and analysis, which covers the topics of anaesthesia, radiation dose and image registration. Because of the expanding research using micro-CT to study other skeletal sites, as well as soft tissues, we also provide a review of current techniques to examine the skull and mandible, adipose tissue, vasculature, tumour severity and cartilage. Lists of recommended further reading and literature references are included to provide the reader with more detail on the methods described. PMID:25184037

Laboratory x-ray micro-computed tomography: a user guideline for biological samples

PubMed Central

2017-01-01

Abstract Laboratory x-ray micro–computed tomography (micro-CT) is a fast-growing method in scientific research applications that allows for non-destructive imaging of morphological structures. This paper provides an easily operated “how to” guide for new potential users and describes the various steps required for successful planning of research projects that involve micro-CT. Background information on micro-CT is provided, followed by relevant setup, scanning, reconstructing, and visualization methods and considerations. Throughout the guide, a Jackson's chameleon specimen, which was scanned at different settings, is used as an interactive example. The ultimate aim of this paper is make new users familiar with the concepts and applications of micro-CT in an attempt to promote its use in future scientific studies. PMID:28419369

High resolution 3D laboratory x-ray tomography data of femora from young, 1-14 day old C57BL/6 mice.

PubMed

Bortel, Emely L; Duda, Georg N; Mundlos, Stefan; Willie, Bettina M; Fratzl, Peter; Zaslansky, Paul

2015-09-01

This data article contains high resolution (1.2 µm effective pixel size) lab-based micro-computed tomography (µCT) reconstructed volume data of the femoral mid-shafts from young C57BL/6 mice. This data formed the basis for the analyses of bone structural development in healthy mice, including closed and open porosity as reported in Bortel et al. [1]. The data reveals changes seen in bone material and porosity distribution observed when mouse bones transform from porous scaffolds into solid structures during normal organogenesis.

Adjunctive Steps for Disinfection of the Mandibular Molar Root Canal System: A Correlative Bacteriologic, Micro-Computed Tomography, and Cryopulverization Approach.

PubMed

Alves, Flávio R F; Andrade-Junior, Carlos V; Marceliano-Alves, Marília F; Pérez, Alejandro R; Rôças, Isabela N; Versiani, Marco A; Sousa-Neto, Manoel D; Provenzano, José C; Siqueira, José F

2016-11-01

This study evaluated the disinfecting ability of chemomechanical preparation with rotary nickel-titanium instruments, followed by 2 distinct adjunctive procedures in the root canals of extracted mandibular molars by means of a correlative analytical approach. Twenty-two extracted mandibular molars were selected and anatomically matched between groups on the basis of micro-computed tomographic analysis. In the first phase of the experiment, root canals were contaminated with Enterococcus faecalis and subjected to chemomechanical preparation with BT RaCe instruments and 2.5% NaOCl irrigation. Then either XP-Endo Finisher instrument or passive ultrasonic irrigation was used to supplement disinfection. Micro-computed tomography was used to show whether the percentage of unprepared areas correlated to bacterial counts. In the second phase, the same teeth were contaminated once again, and the adjunctive procedures were used. Samples from the isthmus area of mesial roots and the apical 5-mm fragment of distal roots were obtained by cryopulverization. Samples taken before and after treatment steps in both phases were evaluated by quantitative polymerase chain reaction and statistically analyzed. In phase 1, preparation in both groups resulted in substantial decrease of bacterial counts (P < .001). The adjunctive approaches led to a further small bacterial reduction, which was significant for XP-Endo Finisher (P < .05). No significant differences were observed between groups for persisting bacterial counts. Correlative analysis revealed no statistically significant relationship between bacterial reduction and the percentage of unprepared areas (P > .05). In phase 2, both methods had significant antibacterial effects in the main canal, but none of them could predictably disinfect the isthmus/recess areas. Both XP-Endo Finisher and passive ultrasonic irrigation exhibited antibacterial effectiveness, but only the former caused a significant reduction in the bacterial counts after chemomechanical preparation. None of them were effective in predictably disinfecting the isthmus/recess areas. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

In vivo quantitative bioluminescence tomography using heterogeneous and homogeneous mouse models.

PubMed

Liu, Junting; Wang, Yabin; Qu, Xiaochao; Li, Xiangsi; Ma, Xiaopeng; Han, Runqiang; Hu, Zhenhua; Chen, Xueli; Sun, Dongdong; Zhang, Rongqing; Chen, Duofang; Chen, Dan; Chen, Xiaoyuan; Liang, Jimin; Cao, Feng; Tian, Jie

2010-06-07

Bioluminescence tomography (BLT) is a new optical molecular imaging modality, which can monitor both physiological and pathological processes by using bioluminescent light-emitting probes in small living animal. Especially, this technology possesses great potential in drug development, early detection, and therapy monitoring in preclinical settings. In the present study, we developed a dual modality BLT prototype system with Micro-computed tomography (MicroCT) registration approach, and improved the quantitative reconstruction algorithm based on adaptive hp finite element method (hp-FEM). Detailed comparisons of source reconstruction between the heterogeneous and homogeneous mouse models were performed. The models include mice with implanted luminescence source and tumor-bearing mice with firefly luciferase report gene. Our data suggest that the reconstruction based on heterogeneous mouse model is more accurate in localization and quantification than the homogeneous mouse model with appropriate optical parameters and that BLT allows super-early tumor detection in vivo based on tomographic reconstruction of heterogeneous mouse model signal.

Optical coherence tomography for embryonic imaging: a review

PubMed Central

Raghunathan, Raksha; Singh, Manmohan; Dickinson, Mary E.; Larin, Kirill V.

2016-01-01

Abstract. Embryogenesis is a highly complex and dynamic process, and its visualization is crucial for understanding basic physiological processes during development and for identifying and assessing possible defects, malformations, and diseases. While traditional imaging modalities, such as ultrasound biomicroscopy, micro-magnetic resonance imaging, and micro-computed tomography, have long been adapted for embryonic imaging, these techniques generally have limitations in their speed, spatial resolution, and contrast to capture processes such as cardiodynamics during embryogenesis. Optical coherence tomography (OCT) is a noninvasive imaging modality with micrometer-scale spatial resolution and imaging depth up to a few millimeters in tissue. OCT has bridged the gap between ultrahigh resolution imaging techniques with limited imaging depth like confocal microscopy and modalities, such as ultrasound sonography, which have deeper penetration but poorer spatial resolution. Moreover, the noninvasive nature of OCT has enabled live imaging of embryos without any external contrast agents. We review how OCT has been utilized to study developing embryos and also discuss advances in techniques used in conjunction with OCT to understand embryonic development. PMID:27228503

Early changes in coronary artery wall structure detected by microcomputed tomography in experimental hypercholesterolemia.

PubMed

Zhu, Xiang-Yang; Bentley, Michael D; Chade, Alejandro R; Ritman, Erik L; Lerman, Amir; Lerman, Lilach O

2007-09-01

Changes in the structure of the artery wall commence shortly after exposure to cardiovascular risk factors, such as hypercholesterolemia (HC), but may be difficult to detect. The ability to study vascular wall structure could be helpful in evaluation of the factors that instigate atherosclerosis and its pathomechanisms. The present study tested the hypothesis that early morphological changes in coronary arteries of hypercholesterolemic (HC) pigs can be detected using the novel X-ray contrast agent OsO(4) and three-dimensional micro-computed tomography (CT). Two groups of pigs were studied after they were fed a normal or an HC (2% cholesterol) diet for 12 wk. Hearts were harvested, coronary arteries were injected with 1% OsO(4) solution, and cardiac samples (6-mum-thick) were scanned by micro-CT. Layers of the epicardial coronary artery wall, early lesions, and perivascular OsO(4) accumulation were determined. Leakage of OsO(4) from myocardial microvessels was used to assess vascular permeability, which was correlated with immunoreactivity of vascular endothelial growth factor in corresponding histological cross sections. OsO(4) enhanced the visualization of coronary artery wall layers and facilitated detection of early lesions in HC in longitudinal tomographic sections of vascular segments. Increased density of perivascular OsO(4) in HC was correlated with increased vascular endothelial growth factor expression and suggested increased microvascular permeability. The use of OsO(4) as a contrast agent in micro-CT allows three-dimensional visualization of coronary artery wall structure, early lesion formation, and changes in vascular permeability. Therefore, this technique can be a useful tool in atherosclerosis research.

Subantibiotic dose of azithromycin attenuates alveolar bone destruction and improves trabecular microarchitectures in a rat model of experimental periodontitis: A study using micro-computed tomography.

PubMed

Park, Hye-Shin; Lee, Yong Sun; Choi, Eun-Young; Choi, Jeom-Il; Choi, In Soon; Kim, Sung-Jo

2017-06-01

Azithromycin, a macrolide antibiotic, has anti-inflammatory and immunomodulatory activities apart from its antibacterial properties. In this study, we examined the efficacy of subantibiotic dose of azithromycin on ligature-induced periodontitis in rats using micro-computed tomography (micro-CT) imaging and bone parameter analysis. Male Sprague-Dawley rats were allocated to the following four groups: non-ligation (NL) group; ligation-only (L) group; ligation-plus-subantibiotic dose azithromycin (SA) group; and 4) ligation-plus-antibiotic dose azithromycin (AA) group. The rats from Groups L, SA and AA were subjected to periodontitis by placing a ligature around lower right first molar. Immediately after ligation, the rats in SA and AA groups received daily intraperitoneal injections of azithromycin at a dosage of 3.5 or 10mg/kg body weight, respectively. The ligatures were maintained for 2weeks at which time the rats had their mandibles hemisected for micro-CT analysis. Subantibiotic dose of azithromycin strongly suppressed reductions in alveolar bone height and bone volume fraction caused by experimental periodontitis. When subantibiotic dosage of azithromycin was administered to rats, ligature-induced alterations in microarchitectural parameters of trabecular bone were significantly reversed. Rats treated with subantibiotic dose of azithromycin presented no significant difference compared to rats with antibiotic dosage in all parameters. While further studies are necessary, subantibiotic dose of azithromycin could be utilized as a host modulator for the treatment of periodontitis. Copyright © 2017 Elsevier B.V. All rights reserved.

Soy protein is beneficial but high-fat diet and voluntary running are detrimental to bone structure in mice

USDA-ARS?s Scientific Manuscript database

We investigated the effects of diet (AIN93G or high-fat), physical activity (sedentary or voluntary running) and protein source (casein or soy protein isolate) and their interactions on bone microstructural changes in distal femurs in male C57BL/6 mice by using micro-computed tomography. After 14 w...

Micro-Computed Tomography Detection of Gold Nanoparticle-Labelled Mesenchymal Stem Cells in the Rat Subretinal Layer.

PubMed

Mok, Pooi Ling; Leow, Sue Ngein; Koh, Avin Ee-Hwan; Mohd Nizam, Hairul Harun; Ding, Suet Lee Shirley; Luu, Chi; Ruhaslizan, Raduan; Wong, Hon Seng; Halim, Wan Haslina Wan Abdul; Ng, Min Hwei; Idrus, Ruszymah Binti Hj; Chowdhury, Shiplu Roy; Bastion, Catherine Mae-Lynn; Subbiah, Suresh Kumar; Higuchi, Akon; Alarfaj, Abdullah A; Then, Kong Yong

2017-02-08

Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases.

Micro-Computed Tomography Detection of Gold Nanoparticle-Labelled Mesenchymal Stem Cells in the Rat Subretinal Layer

PubMed Central

Mok, Pooi Ling; Leow, Sue Ngein; Koh, Avin Ee-Hwan; Mohd Nizam, Hairul Harun; Ding, Suet Lee Shirley; Luu, Chi; Ruhaslizan, Raduan; Wong, Hon Seng; Halim, Wan Haslina Wan Abdul; Ng, Min Hwei; Idrus, Ruszymah Binti Hj.; Chowdhury, Shiplu Roy; Bastion, Catherine Mae-Lynn; Subbiah, Suresh Kumar; Higuchi, Akon; Alarfaj, Abdullah A.; Then, Kong Yong

2017-01-01

Mesenchymal stem cells are widely used in many pre-clinical and clinical settings. Despite advances in molecular technology; the migration and homing activities of these cells in in vivo systems are not well understood. Labelling mesenchymal stem cells with gold nanoparticles has no cytotoxic effect and may offer suitable indications for stem cell tracking. Here, we report a simple protocol to label mesenchymal stem cells using 80 nm gold nanoparticles. Once the cells and particles were incubated together for 24 h, the labelled products were injected into the rat subretinal layer. Micro-computed tomography was then conducted on the 15th and 30th day post-injection to track the movement of these cells, as visualized by an area of hyperdensity from the coronal section images of the rat head. In addition, we confirmed the cellular uptake of the gold nanoparticles by the mesenchymal stem cells using transmission electron microscopy. As opposed to other methods, the current protocol provides a simple, less labour-intensive and more efficient labelling mechanism for real-time cell tracking. Finally, we discuss the potential manipulations of gold nanoparticles in stem cells for cell replacement and cancer therapy in ocular disorders or diseases. PMID:28208719

Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation

PubMed Central

Kang, Sung-Won; Lee, Woo-Jin; Choi, Soon-Chul; Lee, Sam-Sun; Heo, Min-Suk; Huh, Kyung-Hoe

2015-01-01

Purpose We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). Materials and Methods The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. Results VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). Conclusion It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method. PMID:25793178

Impact of mineral precipitation on flow and mixing in porous media determined by microcomputed tomography and MRI

DOE PAGES

Bray, Joshua M.; Lauchnor, Ellen G.; Redden, George D.; ...

2016-12-21

Here, precipitation reactions in porous media influence transport properties of the environment and can control advective and dispersive transport. In subsurface environments, mixing of saline groundwater or injected solutions for remediation with fresh groundwater can induce supersaturation of constituents and drive precipitation reactions. Magnetic resonance imaging (MRI) and micro-computed tomography (µ-CT) were employed as complimentary techniques to evaluate advection, dispersion and formation of precipitate in a 3D porous media flow cell. Two parallel fluids were flowed concentrically through the porous media under two flow rate conditions with Na 2CO 3 and CaCl 2 in the inner and outer fluids, respectively.more » Upon mixing, calcium carbonate became supersaturated and formed a precipitate at the interface of the two fluids. Spatial maps of changing local velocity fields and dispersion in the flow cell were generated from MRI, while high resolution imaging of the precipitate formed in the porous media was achieved via µ-CT imaging. Formation of a precipitate layer minimized dispersive and advective transport between the two fluids and the shape of the precipitation was influenced by the flow rate condition.« less

Impact of mineral precipitation on flow and mixing in porous media determined by microcomputed tomography and MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bray, Joshua M.; Lauchnor, Ellen G.; Redden, George D.

Here, precipitation reactions in porous media influence transport properties of the environment and can control advective and dispersive transport. In subsurface environments, mixing of saline groundwater or injected solutions for remediation with fresh groundwater can induce supersaturation of constituents and drive precipitation reactions. Magnetic resonance imaging (MRI) and micro-computed tomography (µ-CT) were employed as complimentary techniques to evaluate advection, dispersion and formation of precipitate in a 3D porous media flow cell. Two parallel fluids were flowed concentrically through the porous media under two flow rate conditions with Na 2CO 3 and CaCl 2 in the inner and outer fluids, respectively.more » Upon mixing, calcium carbonate became supersaturated and formed a precipitate at the interface of the two fluids. Spatial maps of changing local velocity fields and dispersion in the flow cell were generated from MRI, while high resolution imaging of the precipitate formed in the porous media was achieved via µ-CT imaging. Formation of a precipitate layer minimized dispersive and advective transport between the two fluids and the shape of the precipitation was influenced by the flow rate condition.« less

If the skull fits: magnetic resonance imaging and microcomputed tomography for combined analysis of brain and skull phenotypes in the mouse

PubMed Central

Blank, Marissa C.; Roman, Brian B.; Henkelman, R. Mark; Millen, Kathleen J.

2012-01-01

The mammalian brain and skull develop concurrently in a coordinated manner, consistently producing a brain and skull that fit tightly together. It is common that abnormalities in one are associated with related abnormalities in the other. However, this is not always the case. A complete characterization of the relationship between brain and skull phenotypes is necessary to understand the mechanisms that cause them to be coordinated or divergent and to provide perspective on the potential diagnostic or prognostic significance of brain and skull phenotypes. We demonstrate the combined use of magnetic resonance imaging and microcomputed tomography for analysis of brain and skull phenotypes in the mouse. Co-registration of brain and skull images allows comparison of the relationship between phenotypes in the brain and those in the skull. We observe a close fit between the brain and skull of two genetic mouse models that both show abnormal brain and skull phenotypes. Application of these three-dimensional image analyses in a broader range of mouse mutants will provide a map of the relationships between brain and skull phenotypes generally and allow characterization of patterns of similarities and differences. PMID:22947655

Quantitative ex-vivo micro-computed tomographic imaging of blood vessels and necrotic regions within tumors.

PubMed

Downey, Charlene M; Singla, Arvind K; Villemaire, Michelle L; Buie, Helen R; Boyd, Steven K; Jirik, Frank R

2012-01-01

Techniques for visualizing and quantifying the microvasculature of tumors are essential not only for studying angiogenic processes but also for monitoring the effects of anti-angiogenic treatments. Given the relatively limited information that can be gleaned from conventional 2-D histological analyses, there has been considerable interest in methods that enable the 3-D assessment of the vasculature. To this end, we employed a polymerizing intravascular contrast medium (Microfil) and micro-computed tomography (micro-CT) in combination with a maximal spheres direct 3-D analysis method to visualize and quantify ex-vivo vessel structural features, and to define regions of hypoperfusion within tumors that would be indicative of necrosis. Employing these techniques we quantified the effects of a vascular disrupting agent on the tumor vasculature. The methods described herein for quantifying whole tumor vascularity represent a significant advance in the 3-D study of tumor angiogenesis and evaluation of novel therapeutics, and will also find potential application in other fields where quantification of blood vessel structure and necrosis are important outcome parameters.

Insights into the dissolution and the three-dimensional structure of insensitive munitions formulations.

PubMed

Taylor, Susan; Ringelberg, David B; Dontsova, Katerina; Daghlian, Charles P; Walsh, Marianne E; Walsh, Michael R

2013-11-01

Two compounds, 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO) are the main ingredients in a suite of explosive formulations that are being, or soon will be, fielded at military training ranges. We aim to understand the dissolution characteristics of DNAN and NTO and three insensitive muntions (IM) formulations that contain them. This information is needed to accurately predict the environmental fate of IM constituents, some of which may be toxic to people and the environment. We used Raman spectroscopy to identify the different constituents in the IM formulations and micro computed tomography to image their three-dimensional structure. These are the first three-dimensional images of detonated explosive particles. For multi-component explosives the solubility of the individual constituents and the fraction of each constituent wetted by water controls the dissolution. We found that the order of magnitude differences in solubility amongst the constituents of these IM formulations quickly produced hole-riddled particles when these were exposed to water. Micro-computed tomography showed that particles resulting from field detonations were fractured, producing conduits by which water could access the interior of the particle. We think that micro-computed tomography can also be used to determine the initial composition of IM particles and to track how their compositions change as the particles dissolve. This information is critical to quantifying dissolution and developing physically based dissolution models. Published by Elsevier Ltd.

A brief review of chronic obstructive pulmonary disease.

PubMed

Hogg, James C

2012-01-01

A recent study, based on a combination of multidetector computed tomography scanning of an intact specimen with microcomputed tomography and histological analysis of lung tissue samples, reported that the number of terminal bronchioles were reduced from approximately 44,500/lung pair in control (donor) lungs to approximately 4800/lung pair in lungs donated by individuals with very severe (Global initiative for chronic Obstructive Lung Disease stage 4) chronic obstructive pulmonary disease (COPD) treated by lung transplantation. The present short review discusses the hypothesis that a rapid rate of terminal bronchiolar destruction causes the rapid decline in lung function leading to advanced COPD. With respect to why the terminal bronchioles are targeted for destruction, the postulated mechanisms of this destruction and the possibility that new treatments are able to either prevent or reverse the underlying cause of airway obstruction in COPD are addressed.

The fixation effect of a silk fibroin-bacterial cellulose composite plate in segmental defects of the zygomatic arch: an experimental study.

PubMed

Lee, Jung Min; Kim, Ji Heui; Lee, Ok Joo; Park, Chan Hum

2013-06-01

Bioresorbable fixation systems have been popular for the treatment of facial fractures. However, their mechanical properties are uncertain and complications have been reported. To overcome these problems, we developed a bioresorbable fixation plate using a composite of silk fibroin and bacterial cellulose (SF-BC) with biodegradability and increased biocompatibility. To investigate the regenerative effect of the bioresorbable SF-BC fixation plate on zygomatic arch defects in rats. In vivo animal study. The SF-BC composite plate had a tensile strength similar to that of a polylactic acid plate and a tight, pore-free microstructure. Bilateral segmental bone defects (2 mm in length) were created in the zygomatic arches of adult rats. One side was fixed with the SF-BC composite plate, and the other side was left without fixation. Academic research laboratory. Fifteen adult Sprague-Dawley rats. Fixation of the zygomatic arch defect with the SF-BC composite plate. Micro-computed tomography and histological evaluation of bone samples. Gross inspection revealed no specific complication. At 1, 2, 4, and 8 postoperative weeks, the zygomatic arches were explored by micro-computed tomography and histological examination. Control sides did not heal completely and showed bony degeneration and necrosis during the 8-week follow-up. However, we observed new bone formation in sides treated with the SF-BC composite plate, and bony defects were completely healed within 8 weeks. The SF-BC composite plate is a potential candidate for a new bioresorbable fixation system. Our composite material could considerably shorten bone regeneration time. Additional study of the control of biodegradability and mechanical properties of SF-BC composite plates and a comparative study with the resorbable plates currently in use should be undertaken.

A micro-computed tomography study of the negotiation and anatomical feature in apical root canal of mandibular molars.

PubMed

Min, Yi; Ma, Jing-Zhi; Shen, Ya; Cheung, Gary Shun-Pan; Gao, Yuan

2016-11-01

The aim of this study was to investigate the clinical negotiation of various apical anatomic features of the mandibular first molars in a Chinese population using micro-computed tomography (micro-CT). A total of 152 mandibular first molars were scanned with micro-CT at 30 µm resolution. The apical 5 mm of root canal (ARC) was reconstructed three dimensionally and classified. Subsequently, the access cavity was prepared with the ARC anatomy blinded to the operator. The ARC was negotiated with a size 10 K file with or without precurve. Information on the ability to obtain a reproducible glide path was recorded. The anatomical classification of ARC was Type I with 68.45% in mandibular first molars. The negotiation result of ARC with Category i was 387 canals (74.00%). With a bent negotiating file, 96 canals were negotiated, including 88 reproducible glide paths (Category ii) and 8 irregular glide paths (Category iii). About 7.65% canals could not be negotiated with patency successfully (Category iv). The statistical analyze shown the anatomic feature of ARC had effect on the negotiation of ARC (p < 0.05). In conclusion, ARC anatomic variations had a strong potential impact on the negotiation. The category of negotiation in ARC would be helpful in the using of NiTi rotary instruments. Negotiation of ARC to the working length with patency should be careful and skillful because of the complexities of ARC. SCANNING 38:819-824, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Micro-computed tomography evaluation of the preparation of long oval root canals in mandibular molars with the self-adjusting file.

PubMed

Paqué, Frank; Peters, Ove A

2011-04-01

The aim of this study was to assess the shaping potential of a novel nickel-titanium instrument, the self-adjusting file (SAF), in long oval root canals in distal roots in mandibular molars. Twenty mandibular molars with long oval distal root canals were selected and scanned preoperatively and postoperatively by using micro-computed tomography at an original resolution of 20 μm. Canals were shaped with the SAF, three-dimensionally reconstructed, and evaluated for volume, surface area, canal transportation, and prepared surface. Data were statistically contrasted by using paired t tests and regression analysis. Preoperatively, canal volume was 7.73 ± 2.13 mm(3), and canal area was 42.83 ± 8.14 mm(2). Volumes and surface areas increased significantly (P < .001) by 4.84 ± 1.73 mm(3) and 3.34 ± 1.73 mm(2), respectively, and no gross preparation errors were detected. Unprepared canal surface varied between individual canals, and mean unprepared surface was 23.5% ± 8.9%. Prepared areas were significantly larger compared with rotary canal preparation done in a previous study. Canal transportation scores were higher in the coronal root canal third (106 ± 50 μm) compared with the apical third (81 ± 49 μm). In vitro, preparation of long oval-shaped root canals in mandibular molars with the SAF was effective and safe. Moreover, shapes generated with the SAF were more complete compared with rotary canal preparation. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Comparison of mandibular first molar mesial root canal morphology using micro-computed tomography and clearing technique.

PubMed

Kim, Yeun; Perinpanayagam, Hiran; Lee, Jong-Ki; Yoo, Yeon-Jee; Oh, Soram; Gu, Yu; Lee, Seung-Pyo; Chang, Seok Woo; Lee, Woocheol; Baek, Seung-Ho; Zhu, Qiang; Kum, Kee-Yeon

2015-08-01

Micro-computed tomography (MCT) with alternative image reformatting techniques shows complex and detailed root canal anatomy. This study compared two-dimensional (2D) and 3D MCT image reformatting with standard tooth clearing for studying mandibular first molar mesial root canal morphology. Extracted human mandibular first molar mesial roots (n=31) were scanned by MCT (Skyscan 1172). 2D thin-slab minimum intensity projection (TS-MinIP) and 3D volume rendered images were constructed. The same teeth were then processed by clearing and staining. For each root, images obtained from clearing, 2D, 3D and combined 2D and 3D techniques were examined independently by four endodontists and categorized according to Vertucci's classification. Fine anatomical structures such as accessory canals, intercanal communications and loops were also identified. Agreement among the four techniques for Vertucci's classification was 45.2% (14/31). The most frequent were Vertucci's type IV and then type II, although many had complex configurations that were non-classifiable. Generally, complex canal systems were more clearly visible in MCT images than with standard clearing and staining. Fine anatomical structures such as intercanal communications, accessory canals and loops were mostly detected with a combination of 2D TS-MinIP and 3D volume-rendering MCT images. Canal configurations and fine anatomic structures were more clearly observed in the combined 2D and 3D MCT images than the clearing technique. The frequency of non-classifiable configurations demonstrated the complexity of mandibular first molar mesial root canal anatomy.

Integrated 3D view of postmating responses by the Drosophila melanogaster female reproductive tract, obtained by micro-computed tomography scanning

PubMed Central

Mattei, Alexandra L.; Riccio, Mark L.; Avila, Frank W.; Wolfner, Mariana F.

2015-01-01

Physiological changes in females during and after mating are triggered by seminal fluid components in conjunction with female-derived molecules. In insects, these changes include increased egg production, storage of sperm, and changes in muscle contraction within the reproductive tract (RT). Such postmating changes have been studied in dissected RT tissues, but understanding their coordination in vivo requires a holistic view of the tissues and their interrelationships. Here, we used high-resolution, multiscale micro-computed tomography (CT) scans to visualize and measure postmating changes in situ in the Drosophila female RT before, during, and after mating. These studies reveal previously unidentified dynamic changes in the conformation of the female RT that occur after mating. Our results also reveal how the reproductive organs temporally shift in concert within the confines of the abdomen. For example, we observed chiral loops in the uterus and in the upper common oviduct that relax and constrict throughout sperm storage and egg movement. We found that specific seminal fluid proteins or female secretions mediate some of the postmating changes in morphology. The morphological movements, in turn, can cause further changes due to the connections among organs. In addition, we observed apparent copulatory damage to the female intima, suggesting a mechanism for entry of seminal proteins, or other exogenous components, into the female’s circulatory system. The 3D reconstructions provided by high-resolution micro-CT scans reveal how male and female molecules and anatomy interface to carry out and coordinate mating-dependent changes in the female’s reproductive physiology. PMID:26041806

Vancomycin-modified implant surface inhibits biofilm formation and supports bone-healing in an infected osteotomy model in sheep: a proof-of-concept study.

PubMed

Stewart, Suzanne; Barr, Stephanie; Engiles, Julie; Hickok, Noreen J; Shapiro, Irving M; Richardson, Dean W; Parvizi, Javad; Schaer, Thomas P

2012-08-01

Implant-associated infections contribute to patient morbidity and health care costs. We hypothesized that surface modification of titanium fracture hardware with vancomycin would support bone-healing and prevent bacterial colonization of the implant in a large-animal model. A unilateral transverse mid-diaphyseal tibial osteotomy was performed and repaired with a titanium locking compression plate in nine sheep. Four control animals were treated with an unmodified plate and five experimental animals were treated with a vancomycin-modified plate. The osteotomy was inoculated with 2.5 × 106 colony-forming units of Staphylococcus aureus. The animals were killed at three months postoperatively, and implants were retrieved aseptically. Microbiologic and histologic analyses, scanning electron and confocal microscopy, and microcomputed tomography were performed. All animals completed the study. Compared with the treatment cohort, control animals exhibited protracted lameness in the operatively treated leg. Gross findings during necropsy were consistent with an infected osteotomy accompanied by a florid and lytic callus. Microcomputed tomography and histologic analysis of the tibiae further supported the presence of septic osteomyelitis in the control cohort. Thick biofilms were also evident, and bacterial cultures were positive for Staphylococcus aureus in three of four control animals. In contrast, animals treated with vancomycin-treated plates exhibited a healed osteotomy site with homogenous remodeling, there was no evidence of biofilm formation on the retrieved plate, and bacterial cultures from only one of five animals were positive for Staphylococcus aureus. Vancomycin-derivatized plate surfaces inhibited implant colonization with Staphylococcus aureus and supported bone-healing in an infected large-animal model.

Potential and limitations of X-Ray micro-computed tomography in arthropod neuroanatomy: A methodological and comparative survey

PubMed Central

Sombke, Andy; Lipke, Elisabeth; Michalik, Peter; Uhl, Gabriele; Harzsch, Steffen

2015-01-01

Classical histology or immunohistochemistry combined with fluorescence or confocal laser scanning microscopy are common techniques in arthropod neuroanatomy, and these methods often require time-consuming and difficult dissections and sample preparations. Moreover, these methods are prone to artifacts due to compression and distortion of tissues, which often result in information loss and especially affect the spatial relationships of the examined parts of the nervous system in their natural anatomical context. Noninvasive approaches such as X-ray micro-computed tomography (micro-CT) can overcome such limitations and have been shown to be a valuable tool for understanding and visualizing internal anatomy and structural complexity. Nevertheless, knowledge about the potential of this method for analyzing the anatomy and organization of nervous systems, especially of taxa with smaller body size (e.g., many arthropods), is limited. This study set out to analyze the brains of selected arthropods with micro-CT, and to compare these results with available histological and immunohistochemical data. Specifically, we explored the influence of different sample preparation procedures. Our study shows that micro-CT is highly suitable for analyzing arthropod neuroarchitecture in situ and allows specific neuropils to be distinguished within the brain to extract quantitative data such as neuropil volumes. Moreover, data acquisition is considerably faster compared with many classical histological techniques. Thus, we conclude that micro-CT is highly suitable for targeting neuroanatomy, as it reduces the risk of artifacts and is faster than classical techniques. J. Comp. Neurol. 523:1281–1295, 2015. © 2015 Wiley Periodicals, Inc. PMID:25728683

Particle-induced osteolysis in three-dimensional micro-computed tomography.

PubMed

Wedemeyer, Christian; Xu, Jie; Neuerburg, Carl; Landgraeber, Stefan; Malyar, Nasser M; von Knoch, Fabian; Gosheger, Georg; von Knoch, Marius; Löer, Franz; Saxler, Guido

2007-11-01

Small-animal models are useful for the in vivo study of particle-induced osteolysis, the most frequent cause of aseptic loosening after total joint replacement. Microstructural changes associated with particle-induced osteolysis have been extensively explored using two-dimensional (2D) techniques. However, relatively little is known regarding the 3D dynamic microstructure of particle-induced osteolysis. Therefore, we tested micro-computed tomography (micro-CT) as a novel tool for 3D analysis of wear debris-mediated osteolysis in a small-animal model of particle-induced osteolysis. The murine calvarial model based on polyethylene particles was utilized in 14 C57BL/J6 mice randomly divided into two groups. Group 1 received sham surgery, and group 2 was treated with polyethylene particles. We performed 3D micro-CT analysis and histological assessment. Various bone morphometric parameters were assessed. Regression was used to examine the relation between the results achieved by the two methods. Micro-CT analysis provides a fully automated means to quantify bone destruction in a mouse model of particle-induced osteolysis. This method revealed that the osteolytic lesions in calvaria in the experimental group were affected irregularly compared to the rather even distribution of osteolysis in the control group. This is an observation which would have been missed if histomorphometric analysis only had been performed, leading to false assessment of the actual situation. These irregularities seen by micro-CT analysis provide new insight into individual bone changes which might otherwise be overlooked by histological analysis and can be used as baseline information on which future studies can be designed.

3D mapping of polymerization shrinkage using X-ray micro-computed tomography to predict microleakage.

PubMed

Sun, Jirun; Eidelman, Naomi; Lin-Gibson, Sheng

2009-03-01

The objectives of this study were to (1) demonstrate X-ray micro-computed tomography (microCT) as a viable method for determining the polymerization shrinkage and microleakage on the same sample accurately and non-destructively, and (2) investigate the effect of sample geometry (e.g., C-factor and volume) on polymerization shrinkage and microleakage. Composites placed in a series of model cavities of controlled C-factors and volumes were imaged using microCT to determine their precise location and volume before and after photopolymerization. Shrinkage was calculated by comparing the volume of composites before and after polymerization and leakage was predicted based on gap formation between composites and cavity walls as a function of position. Dye penetration experiments were used to validate microCT results. The degree of conversion (DC) of composites measured using FTIR microspectroscopy in reflectance mode was nearly identical for composites filled in all model cavity geometries. The shrinkage of composites calculated based on microCT results was statistically identical regardless of sample geometry. Microleakage, on the other hand, was highly dependent on the C-factor as well as the composite volume, with higher C-factors and larger volumes leading to a greater probability of microleakage. Spatial distribution of microleakage determined by microCT agreed well with results determined by dye penetration. microCT has proven to be a powerful technique in quantifying polymerization shrinkage and corresponding microleakage for clinically relevant cavity geometries.

Effects of the bilayer nano-hydroxyapatite/mineralized collagen-guided bone regeneration membrane on site preservation in dogs.

PubMed

Sun, Yi; Wang, Chengyue; Chen, Qixin; Liu, Hai; Deng, Chao; Ling, Peixue; Cui, Fu-Zhai

2017-08-01

This study was aimed at assessing the effects of the porous mineralized collagen plug with or without the bilayer mineralized collagen-guided bone regeneration membrane on alveolar ridge preservation in dogs. The third premolars in the bilateral maxilla of mongrel dogs ( N = 12) were extracted. Twenty-four alveolar sockets were thus randomly divided into three groups: membrane + collagen plug (MP, n = 8), nonmembrane + collagen plug (NP, n = 8) and blank group without any implantation (BG, n = 8). Radiographic assessment was carried out immediately and in the 2nd, 6th, and 12th week after surgery. The bone-repairing effects of the two grafts were respectively evaluated by clinical observation, X-ray micro-computed tomography examination, and histological analysis in the 8th and 12th week after surgery. Three groups presented excellent osseointegration without any inflammation or dehiscence. X-ray micro-computed tomography and histological assessment indicated that the ratios of new bone formation of MP group were significantly higher than those of NP group and BG group in the 8th and 12th week after surgery ( P < 0.05). As a result, the porous mineralized collagen plug with or without the bilayer mineralized collagen-guided bone regeneration membrane could reduce the absorption of alveolar ridge compared to BG group, and the combined use of porous mineralized collagen plug and bilayer mineralized collagen-guided bone regeneration could further improve the activity of bone regeneration.

Three-dimensional representation of the human cochlea using micro-computed tomography data: presenting an anatomical model for further numerical calculations.

PubMed

Braun, Katharina; Böhnke, Frank; Stark, Thomas

2012-06-01

We present a complete geometric model of the human cochlea, including the segmentation and reconstruction of the fluid-filled chambers scala tympani and scala vestibuli, the lamina spiralis ossea and the vibrating structure (cochlear partition). Future fluid-structure coupled simulations require a reliable geometric model of the cochlea. The aim of this study was to present an anatomical model of the human cochlea, which can be used for further numerical calculations. Using high resolution micro-computed tomography (µCT), we obtained images of a cut human temporal bone with a spatial resolution of 5.9 µm. Images were manually segmented to obtain the three-dimensional reconstruction of the cochlea. Due to the high resolution of the µCT data, a detailed examination of the geometry of the twisted cochlear partition near the oval and the round window as well as the precise illustration of the helicotrema was possible. After reconstruction of the lamina spiralis ossea, the cochlear partition and the curved geometry of the scala vestibuli and the scala tympani were presented. The obtained data sets were exported as standard lithography (stl) files. These files represented a complete framework for future numerical simulations of mechanical (acoustic) wave propagation on the cochlear partition in the form of mathematical mechanical cochlea models. Additional quantitative information concerning heights, lengths and volumes of the scalae was found and compared with previous results.

Radiographic, microcomputer tomography, and optical coherence tomography investigations of ceramic interfaces

NASA Astrophysics Data System (ADS)

Sinescu, Cosmin; Negrutiu, Meda Lavinia; Ionita, Ciprian; Topala, Florin; Petrescu, Emanuela; Rominu, Roxana; Pop, Daniela Maria; Marsavina, Liviu; Negru, Radu; Bradu, Adrian; Rominu, Mihai; Podoleanu, Adrian Gh.

2010-12-01

Imagistic investigation of the metal-ceramic crowns and fixed partial prostheses represent a very important issue in nowadays dentistry. At this time, in dental office, it is difficult or even impossible to evaluate a metal ceramic crown or bridge before setting it in the oral cavity. The possibilities of ceramic fractures are due to small fracture lines or material defects inside the esthetic layers. Material and methods: In this study 25 metal ceramic crowns and fixed partial prostheses were investigated by radiographic method (Rx), micro computer tomography (MicroCT) and optical coherence tomography (OCT) working in Time Domain, at 1300 nm. The OCT system contains two interferometers and one scanner. For each incident analysis a stuck made of 100 slices was obtain. These slices were used in order to obtain a 3D model of the ceramic interface. Results: RX and MicroCT are very powerful instruments that provide a good characterization of the dental construct. It is important to observe the reflections due to the metal infrastructure that could affect the evaluation of the metal ceramic crowns and bridges. The OCT investigations could complete the imagistic evaluation of the dental construct by offering important information when it is need it.

Comparison of micro-computerized tomography and cone-beam computerized tomography in the detection of accessory canals in primary molars.

PubMed

Acar, Buket; Kamburoğlu, Kıvanç; Tatar, İlkan; Arıkan, Volkan; Çelik, Hakan Hamdi; Yüksel, Selcen; Özen, Tuncer

2015-12-01

This study was performed to compare the accuracy of micro-computed tomography (CT) and cone-beam computed tomography (CBCT) in detecting accessory canals in primary molars. Forty-one extracted human primary first and second molars were embedded in wax blocks and scanned using micro-CT and CBCT. After the images were taken, the samples were processed using a clearing technique and examined under a stereomicroscope in order to establish the gold standard for this study. The specimens were classified into three groups: maxillary molars, mandibular molars with three canals, and mandibular molars with four canals. Differences between the gold standard and the observations made using the imaging methods were calculated using Spearman's rho correlation coefficient test. The presence of accessory canals in micro-CT images of maxillary and mandibular root canals showed a statistically significant correlation with the stereomicroscopic images used as a gold standard. No statistically significant correlation was found between the CBCT findings and the stereomicroscopic images. Although micro-CT is not suitable for clinical use, it provides more detailed information about minor anatomical structures. However, CBCT is convenient for clinical use but may not be capable of adequately analyzing the internal anatomy of primary teeth.

X-ray fast tomography and its applications in dynamical phenomena studies in geosciences at Advanced Photon Source

NASA Astrophysics Data System (ADS)

Xiao, Xianghui; Fusseis, Florian; De Carlo, Francesco

2012-10-01

State-of-art synchrotron radiation based micro-computed tomography provides high spatial and temporal resolution. This matches the needs of many research problems in geosciences. In this letter we report the current capabilities in microtomography at sector 2BM at the Advanced Photon Source (APS) of Argonne National Laboratory. The beamline is well suited to routinely acquire three-dimensional data of excellent quality with sub-micron resolution. Fast cameras in combination with a polychromatic beam allow time-lapse experiments with temporal resolutions of down to 200 ms. Data processing utilizes quantitative phase retrieval to optimize contrast in phase contrast tomographic data. The combination of these capabilities with purpose-designed experimental cells allows for a wide range of dynamic studies on geoscientific topics, two of which are summarized here. In the near future, new experimental cells capable of simulating conditions in most geological reservoirs will be available for general use. Ultimately, these advances will be matched by a new wide-field imaging beam line, which will be constructed as part of the APS upgrade. It is expected that even faster tomography with larger field of view can be conducted at this beam line, creating new opportunities for geoscientific studies.

Visualization and prediction of supercritical CO 2 distribution in sandstones during drainage: An in situ synchrotron X-ray micro-computed tomography study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voltolini, Marco; Kwon, Tae-Hyuk; Ajo-Franklin, Jonathan

Pore-scale distribution of supercritical CO 2 (scCO 2) exerts significant control on a variety of key hydrologic as well as geochemical processes, including residual trapping and dissolution. Despite such importance, only a small number of experiments have directly characterized the three-dimensional distribution of scCO 2 in geologic materials during the invasion (drainage) process. Here, we present a study which couples dynamic high-resolution synchrotron X-ray micro-computed tomography imaging of a scCO 2/brine system at in situ pressure/temperature conditions with quantitative pore-scale modeling to allow direct validation of a pore-scale description of scCO2 distribution. The experiment combines high-speed synchrotron radiography with tomographymore » to characterize the brine saturated sample, the scCO 2 breakthrough process, and the partially saturated state of a sandstone sample from the Domengine Formation, a regionally extensive unit within the Sacramento Basin (California, USA). The availability of a 3D dataset allowed us to examine correlations between grains and pores morphometric parameters and the actual distribution of scCO 2 in the sample, including the examination of the role of small-scale sedimentary structure on CO2 distribution. The segmented scCO 2/brine volume was also used to validate a simple computational model based on the local thickness concept, able to accurately simulate the distribution of scCO 2 after drainage. The same method was also used to simulate Hg capillary pressure curves with satisfactory results when compared to the measured ones. Finally, this predictive approach, requiring only a tomographic scan of the dry sample, proved to be an effective route for studying processes related to CO 2 invasion structure in geological samples at the pore scale.« less

Biocompatibility property of 100% strontium-substituted SiO2 -Al2 O3 -P2 O5 -CaO-CaF2 glass ceramics over 26 weeks implantation in rabbit model: Histology and micro-Computed Tomography analysis.

PubMed

Basu, Bikramjit; Sabareeswaran, A; Shenoy, S J

2015-08-01

One of the desired properties for any new biomaterial composition is its long-term stability in a suitable animal model and such property cannot be appropriately assessed by performing short-term implantation studies. While hydroxyapatite (HA) or bioglass coated metallic biomaterials are being investigated for in vivo biocompatibility properties, such study is not extensively being pursued for bulk glass ceramics. In view of their inherent brittle nature, the implant stability as well as impact of long-term release of metallic ions on bone regeneration have been a major concern. In this perspective, the present article reports the results of the in vivo implantation experiments carried out using 100% strontium (Sr)-substituted glass ceramics with the nominal composition of 4.5 SiO2 -3Al2 O3 -1.5P2 O5 -3SrO-2SrF2 for 26 weeks in cylindrical bone defects in rabbit model. The combination of histological and micro-computed tomography analysis provided a qualitative and quantitative understanding of the bone regeneration around the glass ceramic implants in comparison to the highly bioactive HA bioglass implants (control). The sequential polychrome labeling of bone during in vivo osseointegration using three fluorochromes followed by fluorescence microscopy observation confirmed homogeneous bone formation around the test implants. The results of the present study unequivocally confirm the long-term implant stability as well as osteoconductive property of 100% Sr-substituted glass ceramics, which is comparable to that of a known bioactive implant, that is, HA-based bioglass. © 2014 Wiley Periodicals, Inc.

Effect of Porous Titanium Granules on Bone Regeneration and Primary Stability in Maxillary Sinus: A Human Clinical, Histomorphometric, and Microcomputed Tomography Analyses.

PubMed

Dursun, Ceyda Kanli; Dursun, Erhan; Eratalay, Kenan; Orhan, Kaan; Tatar, Ilkan; Baris, Emre; Tözüm, Tolga Fikret

2016-03-01

The aim of this randomized controlled study was to comparatively analyze the new bone (NB), residual bone, and graft-bone association in bone biopsies retrieved from augmented maxillary sinus sites by histomorphometry and microcomputed tomography (MicroCT) in a split-mouth model to test the efficacy of porous titanium granules (PTG) in maxillary sinus augmentation. Fifteen patients were included in the study and each patient was treated with bilateral sinus augmentation procedure using xenograft (equine origine, granule size 1000-2000 μm) and xenograft (1 g) + PTG (granule size 700-1000 μm, pore size >50 μm) (1 g), respectively. After a mean of 8.4 months, 30 bone biopsies were retrieved from the implant sites for three-dimensional MicroCT and two-dimensional histomorphometric analyses. Bone volume and vital NB percentages were calculated. Immediate after core biopsy, implants having standard dimensions were placed and implant stability quotient values were recorded at baseline and 3 months follow-up. There were no significant differences between groups according to residual bone height, residual bone width, implant dimensions, and implant stability quotient values (baseline and 3 months). According to MicroCT and two-dimensional histomorphometric analyses, the volume of newly formed bone was 57.05% and 52.67%, and 56.5% and 55.08% for xenograft + PTG and xenograft groups, respectively. No statistically significant differences found between groups according to NB percentages and higher Hounsfield unit values were found for xenograft + PTG group. The findings of the current study supports that PTG, which is a porous, permanent nonresorbable bone substitute, may have a beneficial osteoconductive effect on mechanical strength of NB in augmented maxillary sinus.

Evaluation of Titanium-Coated Pedicle Screws: In Vivo Porcine Lumbar Spine Model.

PubMed

Kim, Do-Yeon; Kim, Jung-Ryul; Jang, Kyu Yun; Kim, Min Gu; Lee, Kwang-Bok

2016-07-01

Many studies have addressed the problem of loosening pedicle screws in spinal surgery, which is a serious concern. Titanium coating of medical implants (arthroplasty) is common, but few studies involving in vivo spine models have been reported. We evaluated the radiological, mechanical, and histological characteristics of titanium-coated pedicle screws compared with uncoated or hydroxyapatite-coated pedicle screws. Three different types of pedicle screws, i.e., uncoated, hydroxyapatite-coated, and titanium-coated, were implanted into the lumbar 3-4-5 levels of 9 mature miniature pigs. Radiological evaluation of loosening of pedicle screws was performed. Peak torsional extraction torque was tested in the 42 screws from 7 miniature pigs at 12 weeks postoperatively. The implant-bone interface of the remaining 12 pedicle screws from 2 miniature pigs in each group was assessed by micro-computed tomography and histologic studies. The incidence of loosening at 12 weeks postoperatively was not significantly different between the titanium-coated pedicle screw group and the other groups. The titanium-coated pedicle screw group exhibited the greatest mean extraction torsional peak torque at 12 weeks postoperatively (P < 0.05). Quantitative micro-computed tomography data were greatest in the titanium-coated pedicle screw group (P < 0.05). Histologic findings showed osteointegration with densely packed new bone formation at the screw coating-bone interface in the titanium-coated pedicle screw group. Fixation strength was greatest in the titanium-coated pedicle screw group. Osteointegration at the interface between the titanium-coated implant and bone produced prominent and firm bonding. The titanium-coated pedicle screw is a promising device for application in spinal surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

A comparative finite elemental analysis of glass abutment supported and unsupported cantilever fixed partial denture.

PubMed

Ramakrishaniah, Ravikumar; Al Kheraif, Abdulaziz A; Elsharawy, Mohamed A; Alsaleh, Ayman K; Ismail Mohamed, Karem M; Rehman, Ihtesham Ur

2015-05-01

The purpose of this study was to investigate and compare the load distribution and displacement of cantilever prostheses with and without glass abutment by three dimensional finite element analysis. Micro-computed tomography was used to study the relationship between the glass abutment and the ridge. The external surface of the maxilla was scanned, and a simplified finite element model was constructed. The ZX-27 glass abutment and the maxillary first and second premolars were created and modified. The solid model of the three-unit cantilever fixed partial denture was scanned, and the fitting surface was modified with reference to the created abutments using the 3D CAD system. The finite element analysis was completed in ANSYS. The fit and total gap volume between the glass abutment and dental model were determined by Skyscan 1173 high-energy spiral micro-CT scan. The results of the finite element analysis in this study showed that the cantilever prosthesis supported by the glass abutment demonstrated significantly less stress on the terminal abutment and overall deformation of the prosthesis under vertical and oblique load. Micro-computed tomography determined a gap volume of 6.74162 mm(3). By contacting the mucosa, glass abutments transfer some amount of masticatory load to the residual alveolar ridge, thereby preventing damage to the periodontal microstructures of the terminal abutment. The passive contact of the glass abutment with the mucosa not only preserves the health of the mucosa covering the ridge but also permits easy cleaning. It is possible to increase the success rate of cantilever FPDs by supporting the cantilevered pontic with glass abutments. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Visualization and prediction of supercritical CO 2 distribution in sandstones during drainage: An in situ synchrotron X-ray micro-computed tomography study

DOE PAGES

Voltolini, Marco; Kwon, Tae-Hyuk; Ajo-Franklin, Jonathan

2017-10-21

Pore-scale distribution of supercritical CO 2 (scCO 2) exerts significant control on a variety of key hydrologic as well as geochemical processes, including residual trapping and dissolution. Despite such importance, only a small number of experiments have directly characterized the three-dimensional distribution of scCO 2 in geologic materials during the invasion (drainage) process. Here, we present a study which couples dynamic high-resolution synchrotron X-ray micro-computed tomography imaging of a scCO 2/brine system at in situ pressure/temperature conditions with quantitative pore-scale modeling to allow direct validation of a pore-scale description of scCO2 distribution. The experiment combines high-speed synchrotron radiography with tomographymore » to characterize the brine saturated sample, the scCO 2 breakthrough process, and the partially saturated state of a sandstone sample from the Domengine Formation, a regionally extensive unit within the Sacramento Basin (California, USA). The availability of a 3D dataset allowed us to examine correlations between grains and pores morphometric parameters and the actual distribution of scCO 2 in the sample, including the examination of the role of small-scale sedimentary structure on CO2 distribution. The segmented scCO 2/brine volume was also used to validate a simple computational model based on the local thickness concept, able to accurately simulate the distribution of scCO 2 after drainage. The same method was also used to simulate Hg capillary pressure curves with satisfactory results when compared to the measured ones. Finally, this predictive approach, requiring only a tomographic scan of the dry sample, proved to be an effective route for studying processes related to CO 2 invasion structure in geological samples at the pore scale.« less

Three-dimensional quantification of orthodontic root resorption with time-lapsed imaging of micro-computed tomography in a rodent model.

PubMed

Yang, Chongshi; Zhang, Yuanyuan; Zhang, Yan; Fan, Yubo; Deng, Feng

2015-01-01

Despite various X-ray approaches have been widely used to monitor root resorption after orthodontic treatment, a non-invasive and accurate method is highly desirable for long-term follow up. The aim of this study was to build a non-invasive method to quantify longitudinal orthodontic root resorption with time-lapsed images of micro-computed tomography (micro-CT) in a rodent model. Twenty male Sprague Dawley (SD) rats (aged 6-8 weeks, weighing 180-220 g) were used in this study. A 25 g orthodontic force generated by nickel-titanium coil spring was applied to the right maxillary first molar for each rat, while contralateral first molar was severed as a control. Micro-CT scan was performed at day 0 (before orthodontic load) and days 3, 7, 14, and 28 after orthodontic load. Resorption of mesial root of maxillary first molars at bilateral sides was calculated from micro-CT images with registration algorithm via reconstruction, superimposition and partition operations. Obvious resorption of mesial root of maxillary first molar can be detected at day 14 and day 28 at orthodontic side. Most of the resorption occurred in the apical region at distal side and cervical region at mesiolingual side. Desirable development of molar root of rats was identified from day 0 to day 28 at control side. The development of root concentrated on apical region. This non-invasive 3D quantification method with registration algorithm can be used in longitudinal study of root resorption. Obvious root resorption in rat molar can be observed three-dimensionally at day 14 and day 28 after orthodontic load. This indicates that registration algorithm combined with time-lapsed images provides clinic potential application in detection and quantification of root contour.

A Study of Acute and Chronic Tissue Changes in Surgical and Traumatically-Induced Experimental Models of Knee Joint Injury Using Magnetic Resonance Imaging and Micro-Computed Tomography

PubMed Central

Fischenich, Kristine M.; Pauly, Hannah M.; Button, Keith D.; Fajardo, Ryan S.; DeCamp, Charles E.; Haut, Roger C.; Haut Donahue, Tammy L.

2016-01-01

Objective The objective of this study was to monitor the progression of joint damage in two animal models of knee joint trauma using two non-invasive, clinically available imaging modalities. Methods A 3-T clinical magnet and micro-computed tomography (mCT) was used to document changes immediately following injury (acute) and post-injury (chronic) at time points of 4, 8, or 12 weeks. Joint damage was recorded at dissection and compared to the chronic magnetic resonance imaging (MRI) record. Fifteen Flemish Giant rabbits were subjected to a single tibiofemoral compressive impact (ACLF), and 18 underwent a combination of anterior cruciate ligament (ACL) and meniscal transection (mACLT). Results All ACLF animals experienced ACL rupture, and 13 also experienced acute meniscal damage. All ACLF and mACLT animals showed meniscal and articular cartilage damages at dissection. Meniscal damage was documented as early as 4 weeks and worsened in 87% of the ACLF animals and 71% of the mACLT animals. Acute cartilage damage also developed further and increased in occurrence with time in both models. A progressive decrease in bone quantity and quality was documented in both models. The MRI data closely aligned with dissection notes suggesting this clinical tool may be a non-invasive method for documenting joint damage in lapine models of knee joint trauma. Conclusions The study investigates the acute to chronic progression of meniscal and cartilage damage at various time points, and chronic changes to the underlying bone in two models of posttraumatic osteoarthritis (PTOA), and highlights the dependency of the model on the location, type, and progression of damage over time. PMID:27756698

Analysis of micro computed tomography images; a look inside historic enamelled metal objects

NASA Astrophysics Data System (ADS)

van der Linden, Veerle; van de Casteele, Elke; Thomas, Mienke Simon; de Vos, Annemie; Janssen, Elsje; Janssens, Koen

2010-02-01

In this study the usefulness of micro-Computed Tomography (µ-CT) for the in-depth analysis of enamelled metal objects was tested. Usually investigations of enamelled metal artefacts are restricted to non-destructive surface analysis or analysis of cross sections after destructive sampling. Radiography, a commonly used technique in the field of cultural heritage studies, is limited to providing two-dimensional information about a three-dimensional object (Lang and Middleton, Radiography of Cultural Material, pp. 60-61, Elsevier-Butterworth-Heinemann, Amsterdam-Stoneham-London, 2005). Obtaining virtual slices and information about the internal structure of these objects was made possible by CT analysis. With this technique the underlying metal work was studied without removing the decorative enamel layer. Moreover visible defects such as cracks were measured in both width and depth and as of yet invisible defects and weaker areas are visualised. All these features are of great interest to restorers and conservators as they allow a view inside these objects without so much as touching them.

Retrospective Analysis of the Outcome of Ridge Preservation with Anorganic Bovine Bone Minerals: Microcomputed Tomographic Assessment of Wound Healing in Grafted Extraction Sockets.

PubMed

Bakhshalian, Neema; Freire, Marcelo; Min, Seiko; Wu, Ivy; Zadeh, Homayoun H

A total of 68 extraction sockets were grafted with anorganic bovine bone mineral and covered by dense polytetrafluoroethylene membrane. Quantitative analysis of three-dimensional microcomputed tomography imaging of core samples retrieved after a mean of 21.0 ± 14.2 weeks revealed 40.1% bone volume fraction (bone volume [BV]/total volume [TV]) and 12% residual graft. Evidence of de novo bone formation was observed in the form of discrete islands of newly formed bone in direct apposition to graft particles, separated from parent bone. Anterior sockets exhibited a significantly higher percentage of residual graft compared to premolar sockets (P = .05). The BV/TV and percentage of residual graft correlated well with histomorphometric analysis of the same sites, but not with implant outcomes.

Using MicroCT to Assess Periodontal Regeneration Outcomes-Comparison of Image-Based and Histologic Results: A Case Report.

PubMed

Rebaudi, Alberto; Trisi, Paolo; Pagni, Giorgio; Wang, Hom-Lay

The purpose of this study was to compare microcomputed tomography (microCT) and histologic analysis outcomes of a periodontal regeneration of a human defect treated with a polylactic- and polyglycolic-acid copolymer. At 11 months following the grafting procedure, the root with the surrounding periodontal tissues was removed and analyzed using microCT and histologic techniques. The results suggest that microCT three-dimensional analysis may be used in synergy with two-dimensional histologic sections to provide additional information for studying the regeneration outcomes normally reported by histologic biopsies in humans. Additional data is needed to validate these findings.

A generic, geometric cocalibration method for a combined system of fluorescence molecular tomography and microcomputed tomography with arbitrarily shaped objects.

PubMed

Fu, Jianwei; Yang, Xiaoquan; Wang, Kan; Luo, Qingming; Gong, Hui

2011-12-01

A combined system of fluorescence molecular tomography and microcomputed tomography (FMT&mCT) can provide molecular and anatomical information of small animals in a single study with intrinsically coregistered images. The anatomical information provided by the mCT subsystem is commonly used as a reference to locate the fluorophore distribution or as a priori structural information to improve the performance of FMT. Therefore, the transformation between the coordinate systems of the subsystem needs to be determined in advanced. A cocalibration method for the combined system of FMT&mCT is proposed. First, linear models are adopted to describe the galvano mirrors and the charge-coupled device (CCD) camera in the FMT subsystem. Second, the position and orientation of the galvano mirrors are determined with the input voltages of the galvano mirrors and the markers, whose positions are predetermined. The position, orientation and normalized pixel size of the CCD camera are obtained by analysing the projections of a point-like marker at different positions. Finally, the orientation and position of sources and the corresponding relationship between the detectors and their projections on the image plane are predicted. Because the positions of the markers are acquired with mCT, the registration of the FMT and mCT could be realized by direct image fusion. The accuracy and consistency of this method in the presence of noise is evaluated by computer simulation. Next, a practical implementation for an experimental FMT&mCT system is carried out and validated. The maximum prediction error of the source positions on the surface of a cylindrical phantom is within 0.375 mm and that of the projections of a point-like marker is within 0.629 pixel. Finally, imaging experiments of the fluorophore distribution in a cylindrical phantom and a phantom with a complex shape demonstrate the feasibility of the proposed method. This method is universal in FMT&mCT, which could be performed with no restriction on the system geometry, calibration phantoms or imaging objects.

A generic, geometric cocalibration method for a combined system of fluorescence molecular tomography and microcomputed tomography with arbitrarily shaped objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu Jianwei; Yang Xiaoquan; Wang Kan

2011-12-15

Purpose: A combined system of fluorescence molecular tomography and microcomputed tomography (FMT and mCT) can provide molecular and anatomical information of small animals in a single study with intrinsically coregistered images. The anatomical information provided by the mCT subsystem is commonly used as a reference to locate the fluorophore distribution or as a priori structural information to improve the performance of FMT. Therefore, the transformation between the coordinate systems of the subsystem needs to be determined in advanced. Methods: A cocalibration method for the combined system of FMT and mCT is proposed. First, linear models are adopted to describe themore » galvano mirrors and the charge-coupled device (CCD) camera in the FMT subsystem. Second, the position and orientation of the galvano mirrors are determined with the input voltages of the galvano mirrors and the markers, whose positions are predetermined. The position, orientation and normalized pixel size of the CCD camera are obtained by analysing the projections of a point-like marker at different positions. Finally, the orientation and position of sources and the corresponding relationship between the detectors and their projections on the image plane are predicted. Because the positions of the markers are acquired with mCT, the registration of the FMT and mCT could be realized by direct image fusion. Results: The accuracy and consistency of this method in the presence of noise is evaluated by computer simulation. Next, a practical implementation for an experimental FMT and mCT system is carried out and validated. The maximum prediction error of the source positions on the surface of a cylindrical phantom is within 0.375 mm and that of the projections of a point-like marker is within 0.629 pixel. Finally, imaging experiments of the fluorophore distribution in a cylindrical phantom and a phantom with a complex shape demonstrate the feasibility of the proposed method. Conclusions: This method is universal in FMT and mCT, which could be performed with no restriction on the system geometry, calibration phantoms or imaging objects.« less

Contrast Agents for Micro-Computed Tomography of Microdamage in Bone

DTIC Science & Technology

2009-01-01

carboxylate (reported in January 2009), phosphonate and bisphosphonate groups (Fig. 2). The presence of functional groups was verified by FT- IR (Fig. 3...carboxylic acid, (b) phosphonate or (c) bisphosphonate groups for calcium binding damaged tissue. (a) (b) (c) Fig. 3. FT- IR spectra for Au NPs...functional group. Quantitative measurements of the binding affinity were performed by adding hydroxyapatite (HA) crystals to functionalized Au NP solutions in

Detection and distribution analysis of organosilicon compounds in wood by means of SEM-EDX and micro-CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vetter, L. de; Cnudde, V.; Masschaele, B.

This article explores the potential of a scanning electron microscope with an energy dispersive X-ray spectrometer in combination with a new non-destructive 3D visualization technique, X-ray micro-computed tomography, as detection methods for siloxanes/silanes mixtures applied as wood preservatives. In order to have a higher contrast, bromine functional silane was added to the mixture. Scots pine and beech samples were dipped or impregnated with the mixture and subsequently scanned. Both silicon and bromine were easily detectable with both techniques. Dipped siloxanes/silanes covered the cell walls partly in beech and the lumen partly or completely in Scots pine. Impregnated siloxanes/silanes could bemore » found in the cell walls of both wood species. From the results, it can be concluded that, under the circumstances as described in the article, impregnation with a siloxane is necessary to have cell wall penetration. The combination of scanning electron microscopy, energy dispersive X-ray spectroscopy and micro-computed tomography can offer important information concerning the localization of certain products inside wood. While the last of these can monitor changes in 3D, the other two techniques can provide detailed 2D information. Both techniques are complementary and provide important extra information.« less

Potential Bone to Implant Contact Area of Short Versus Standard Implants: An In Vitro Micro-Computed Tomography Analysis.

PubMed

Quaranta, Alessandro; DʼIsidoro, Orlando; Bambini, Fabrizio; Putignano, Angelo

2016-02-01

To compare the available potential bone-implant contact (PBIC) area of standard and short dental implants by micro-computed tomography (μCT) assessment. Three short implants with different diameters (4.5 × 6 mm, 4.1 × 7 mm, and 4.1 × 6 mm) and 2 standard implants (3.5 × 10 mm and 3.3 × 9 mm) with diverse design and surface features were scanned with μCT. Cross-sectional images were obtained. Image data were manually processed to find the plane that corresponds to the most coronal contact point between the crestal bone and implant. The available PBIC was calculated for each sample. Later on, the cross-sectional slices were processed by a 3-dimensional (3D) software, and 3D images of each sample were used for descriptive analysis and display the microtopography and macrotopography. The wide-diameter short implant (4.5 × 6 mm) showed the higher PBIC (210.89 mm) value followed by the standard (178.07 mm and 185.37 mm) and short implants (130.70 mm and 110.70 mm). Wide-diameter short implants show a surface area comparable with standard implants. Micro-CT analysis is a promising technique to evaluate surface area in dental implants with different macrodesign, microdesign, and surface features.

Compression-recovery model of absorptive glass mat (AGM) separator guided by X-ray micro-computed tomography analysis

NASA Astrophysics Data System (ADS)

Kameswara Rao, P. V.; Rawal, Amit; Kumar, Vijay; Rajput, Krishn Gopal

2017-10-01

Absorptive glass mat (AGM) separators play a key role in enhancing the cycle life of the valve regulated lead acid (VRLA) batteries by maintaining the elastic characteristics under a defined level of compression force with the plates of the electrodes. Inevitably, there are inherent challenges to maintain the required level of compression characteristics of AGM separators during the charge and discharge of the battery. Herein, we report a three-dimensional (3D) analytical model for predicting the compression-recovery behavior of AGM separators by formulating a direct relationship with the constituent fiber and structural parameters. The analytical model of compression-recovery behavior of AGM separators has successfully included the fiber slippage criterion and internal friction losses. The presented work uses, for the first time, 3D data of fiber orientation from X-ray micro-computed tomography, for predicting the compression-recovery behavior of AGM separators. A comparison has been made between the theoretical and experimental results of compression-recovery behavior of AGM samples with defined fiber orientation characteristics. In general, the theory agreed reasonably well with the experimental results of AGM samples in both dry and wet states. Through theoretical modeling, fiber volume fraction was established as one of the key structural parameters that modulates the compression hysteresis of an AGM separator.

[Effect of X-ray micro-computed tomography on the metabolic activity and diversity of soil microbial communities in two Chinese soils].

PubMed

Zu, Qianhui; Fang, Huan; Zhou, Hu; Zhang, Jianwei; Peng, Xinhua; Lin, Xiangui; Feng, Youzhi

2016-01-04

X-ray micro-computed tomography (micro-CT) technology, as used in the in situ and nondestructive analysis of soil physical structure, provides the opportunity of associating soil physical and biological assays. Due to the high heterogeneity of the soil matrix, X-ray micro-CT scanning and soil microbial assays should be conducted on the same soil sample. This raises the question whether X-ray micro-CT influences microbial function and diversity of the sample soil to be analyzed. To address this question, we used plate counting, microcalorimetry and pyrosequencing approaches to evaluate the effect of X-ray--at doses typically used in micro-CT--on soil microorganisms in a typical soil of North China Plain, Fluvo-aquic soil and in a typical soil of subtropical China, Ultisol soil, respectively. In both soils radiation decreased the number of viable soil bacteria and disturbed their thermogenic profiles. At DNA level, pyrosequencing revealed that alpha diversities of two soils biota were influenced in opposite ways, while beta diversity was not affected although the relative abundances of some guilds were changed. These findings indicate that the metabolically active aspects of soil biota are not compatible with X-ray micro-CT; while the beta molecular diversity based on pyrosequencing could be compatible.

Synchrotron-radiation-based X-ray micro-computed tomography reveals dental bur debris under dental composite restorations.

PubMed

Hedayat, Assem; Nagy, Nicole; Packota, Garnet; Monteith, Judy; Allen, Darcy; Wysokinski, Tomasz; Zhu, Ning

2016-05-01

Dental burs are used extensively in dentistry to mechanically prepare tooth structures for restorations (fillings), yet little has been reported on the bur debris left behind in the teeth, and whether it poses potential health risks to patients. Here it is aimed to image dental bur debris under dental fillings, and allude to the potential health hazards that can be caused by this debris when left in direct contact with the biological surroundings, specifically when the debris is made of a non-biocompatible material. Non-destructive micro-computed tomography using the BioMedical Imaging & Therapy facility 05ID-2 beamline at the Canadian Light Source was pursued at 50 keV and at a pixel size of 4 µm to image dental bur fragments under a composite resin dental filling. The bur's cutting edges that produced the fragment were also chemically analyzed. The technique revealed dental bur fragments of different sizes in different locations on the floor of the prepared surface of the teeth and under the filling, which places them in direct contact with the dentinal tubules and the dentinal fluid circulating within them. Dispersive X-ray spectroscopy elemental analysis of the dental bur edges revealed that the fragments are made of tungsten carbide-cobalt, which is bio-incompatible.

X-ray micro-computed tomography in willow reveals tissue patterning of reaction wood and delay in programmed cell death.

PubMed

Brereton, Nicholas James Beresford; Ahmed, Farah; Sykes, Daniel; Ray, Michael Jason; Shield, Ian; Karp, Angela; Murphy, Richard James

2015-03-11

Variation in the reaction wood (RW) response has been shown to be a principle component driving differences in lignocellulosic sugar yield from the bioenergy crop willow. The phenotypic cause(s) behind these differences in sugar yield, beyond their common elicitor, however, remain unclear. Here we use X-ray micro-computed tomography (μCT) to investigate RW-associated alterations in secondary xylem tissue patterning in three dimensions (3D). Major architectural alterations were successfully quantified in 3D and attributed to RW induction. Whilst the frequency of vessels was reduced in tension wood tissue (TW), the total vessel volume was significantly increased. Interestingly, a delay in programmed-cell-death (PCD) associated with TW was also clearly observed and readily quantified by μCT. The surprising degree to which the volume of vessels was increased illustrates the substantial xylem tissue remodelling involved in reaction wood formation. The remodelling suggests an important physiological compromise between structural and hydraulic architecture necessary for extensive alteration of biomass and helps to demonstrate the power of improving our perspective of cell and tissue architecture. The precise observation of xylem tissue development and quantification of the extent of delay in PCD provides a valuable and exciting insight into this bioenergy crop trait.

Neutron Tomography and X-ray Tomography as Tools for the Morphological Investigation of Non-mammalian Synapsids

NASA Astrophysics Data System (ADS)

Laaß, Michael; Schillinger, Burkhard; Werneburg, Ingmar

As having evolved on the stem line of mammals, the taxonomy and phylogeny of therapsids (Synapsida) are of special interest with respect to early mammalian evolution. Due to the fact that in most cases soft tissue of fossil vertebrates is not preserved, species can only be distinguished by diagnosis of morphological features of the skeleton. Moreover, investigations of vertebrate fossils are often obstructed, because internal cranial anatomy is usually hidden and parts of the fossils may be embedded in stone matrix. As a consequence, most species of non-mammalian synapsids were only defined on the basis of external skeletal features. Our investigations on Diictodon skulls (Therapsida, Anomodontia) show that non-destructive methods are very useful to clearly distinguish fossil species. We, therefore, propose using modern non-destructive techniques such as neutron tomography, synchrotron tomography, and micro-computed tomography (μCT) as standard tools for the investigation and virtual reconstruction of fossils and to include features of the internal cranial anatomy into morphological descriptions and phylogenetic analyses of fossil vertebrates.

Shaping Ability of Single-file Systems with Different Movements: A Micro-computed Tomographic Study.

PubMed

Santa-Rosa, Joedy; de Sousa-Neto, Manoel Damião; Versiani, Marco Aurelio; Nevares, Giselle; Xavier, Felipe; Romeiro, Kaline; Cassimiro, Marcely; Leoni, Graziela Bianchi; de Menezes, Rebeca Ferraz; Albuquerque, Diana

2016-01-01

This study aimed to perform a rigorous sample standardization and also evaluate the preparation of mesiobuccal (MB) root canals of maxillary molars with severe curvatures using two single-file engine-driven systems (WaveOne with reciprocating motion and OneShape with rotary movement), using micro-computed tomography (micro-CT). Ten MB roots with single canals were included, uniformly distributed into two groups (n=5). The samples were prepared with a WaveOne or OneShape files. The shaping ability and amount of canal transportation were assessed by a comparison of the pre- and post-instrumentation micro-CT scans. The Kolmogorov-Smirnov and t-tests were used for statistical analysis. The level of significance was set at 0.05. Instrumentation of canals increased their surface area and volume. Canal transportation occurred in coronal, middle and apical thirds and no statistical difference was observed between the two systems (P>0.05). In apical third, significant differences were found between groups in canal roundness (in 3 mm level) and perimeter (in 3 and 4 mm levels) (P<0.05). The WaveOne and One Shape single-file systems were able to shape curved root canals, producing minor changes in the canal curvature.

Three-Dimensional Nonlinear Finite Element Analysis and Microcomputed Tomography Evaluation of Microgap Formation in a Dental Implant Under Oblique Loading.

PubMed

Jörn, Daniela; Kohorst, Philipp; Besdo, Silke; Borchers, Lothar; Stiesch, Meike

2016-01-01

Since bacterial leakage along the implant-abutment interface may be responsible for peri-implant infections, a realistic estimation of the interface gap width during function is important for risk assessment. The purpose of this study was to compare two methods for investigating microgap formation in a loaded dental implant, namely, microcomputed tomography (micro-CT) and three-dimensional (3D) nonlinear finite element analysis (FEA); additionally, stresses to be expected during loading were also evaluated by FEA. An implant-abutment complex was inspected for microgaps between the abutment and implant in a micro-CT scanner under an oblique load of 200 N. A numerical model of the situation was constructed; boundary conditions and external load were defined according to the experiment. The model was refined stepwise until its load-displacement behavior corresponded sufficiently to data from previous load experiments. FEA of the final, validated model was used to determine microgap widths. These were compared with the widths as measured in micro-CT inspection. Finally, stress distributions were evaluated in selected regions. No microgaps wider than 13 μm could be detected by micro-CT for the loaded implant. FEA revealed gap widths up to 10 μm between the implant and abutment at the side of load application. Furthermore, FEA predicted plastic deformation in a limited area at the implant collar. FEA proved to be an adequate method for studying microgap formation in dental implant-abutment complexes. FEA is not limited in gap width resolution as are radiologic techniques and can also provide insight into stress distributions within the loaded complex.

Optimizing a micro-computed tomography-based surrogate measurement of bone-implant contact.

PubMed

Meagher, Matthew J; Parwani, Rachna N; Virdi, Amarjit S; Sumner, Dale R

2018-03-01

Histology and backscatter scanning electron microscopy (bSEM) are the current gold standard methods for quantifying bone-implant contact (BIC), but are inherently destructive. Microcomputed tomography (μCT) is a non-destructive alternative, but attempts to validate μCT-based assessment of BIC in animal models have produced conflicting results. We previously showed in a rat model using a 1.5 mm diameter titanium implant that the extent of the metal-induced artefact precluded accurate measurement of bone sufficiently close to the interface to assess BIC. Recently introduced commercial laboratory μCT scanners have smaller voxels and improved imaging capabilities, possibly overcoming this limitation. The goals of the present study were to establish an approach for optimizing μCT imaging parameters and to validate μCT-based assessment of BIC. In an empirical parametric study using a 1.5 mm diameter titanium implant, we determined 90 kVp, 88 µA, 1.5 μm isotropic voxel size, 1600 projections/180°, and 750 ms integration time to be optimal. Using specimens from an in vivo rat experiment, we found significant correlations between bSEM and μCT for BIC with the manufacturer's automated analysis routine (r = 0.716, p = 0.003) or a line-intercept method (r = 0.797, p = 0.010). Thus, this newer generation scanner's improved imaging capability reduced the extent of the metal-induced artefact zone enough to permit assessment of BIC. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:979-986, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Use of micro-computed tomography to evaluate the effects of exercise on preventing the degeneration of articular cartilage in tail-suspended rats

NASA Astrophysics Data System (ADS)

Luan, Hui-Qin; Sun, Lian-Wen; Huang, Yun-Fei; Wu, Xin-tong; Niu, Haijun; Liu, Hong; Fan, Yu-Bo

2015-07-01

Space flight has been shown to induce bone loss and muscle atrophy, which could initiate the degeneration of articular cartilage. Countermeasures to prevent bone loss and muscle atrophy have been explored, but few spaceflight or ground-based studies have focused on the effects on cartilage degeneration. In this study, we investigated the effects of exercise on articular cartilage deterioration in tail-suspended rats. Thirty-two female Sprague-Dawley rats were randomly divided into four groups (n = 8 in each): tail suspension (TS), tail suspension plus passive motion (TSP), tail suspension plus active exercise (TSA), and control (CON) groups. In the TS, TSP, and TSA groups, the rat hindlimbs were unloaded for 21 days by tail suspension. Next, the cartilage thickness and volume, and the attenuation coefficient of the distal femur were evaluated by micro-computed tomography (μCT). Histological analysis was used to assess the surface integrity of the cartilage, cartilage thickness, and chondrocytes. The results showed that: (1) the cartilage thickness on the distal femur was significantly lower in the TS and TSP groups compared with the CON and TSA groups; (2) the cartilage volume in the TS group was significantly lower compared with the CON, TSA, and TSP groups; and (3) histomorphology showed that the chondrocytes formed clusters where the degree of matrix staining was lower in the TS and TSP groups. There were no significant differences between any of these parameters in the CON and TSA groups. The cartilage thickness measurements obtained by μCT and histomorphology correlated well. In general, tail suspension could induce articular cartilage degeneration, but active exercise was effective in preventing this degeneration in tail-suspended rats.

Interrupted orthodontic force results in less root resorption than continuous force in human premolars as measured by microcomputed tomography.

PubMed

Sawicka, Monika; Bedini, Rossella; Wierzbicki, Piotr M; Pameijer, Cornelis H

2014-01-01

Root resorption is an undesirable but very frequently occurring sequel of orthodontic treatment. The aim of this study was to compare root resorption caused by either continuous (CF) or interrupted (IF) orthodontic force. The study was performed on human subjects on 30 first upper and lower premolars scheduled for extraction for orthodontic reasons. During four weeks before extraction 12 teeth were subjected to either CF or IF. The force was generated by a segmental titanium-molybdenum alloy cantilever spring that was activated in buccal direction. Initially a force of 60 CentiNewton was used in both CF and IF groups, the force in the former, however, was reactivated every week for 4 weeks. There was no reactivation of force in the IF group after initial application. A morphometric analysis of root resorption was performed by microcomputed tomography and the extent of tooth movement was measured on stone casts. Furthermore, a Tartarate-Resistant Acidic Phosphatase activity (TRAP), the marker enzyme of osteoclasts and cementoclasts, was determined by histochemical method. The Mann-Whitney U test was used to compare the difference in measured parameters between treatment and control tooth groups. The number of resorption craters was significantly higher and their average volume almost twice as large in the CF compared to the IF group (p < 0.05). However, the distance of tooth displacement was similar for both groups. Cementoclasts were detected with the TRAP technique on the surface of two teeth only; both were subjected to continuous force. The use of IF leads to less destruction of root structure as opposed to continuous force while the same tooth movement was achieved.

Detection of marginal leakage of Class V restorations in vitro by micro-computed tomography.

PubMed

Zhao, X Y; Li, S B; Gu, L J; Li, Y

2014-01-01

This in vitro study evaluated the efficacy of micro-computed tomography (CT) in marginal leakage detection of Class V restorations. Standardized Class V preparations with cervical margins in dentin and occlusal margins in enamel were made in 20 extracted human molars and restored with dental bonding agents and resin composite. All teeth were then immersed in 50% ammoniacal silver nitrate solution for 12 hours, followed by a developing solution for eight hours. Each restoration was scanned by micro-CT, the depth of marginal silver leakage in the central scanning section was measured, and the three-dimensional images of the silver leakage around each restoration were reconstructed. Afterward, all restorations were cut through the center and examined for leakage depth using a microscope. The silver leakage depth of each restoration obtained by the micro-CT and the microscope were compared for equivalency. The silver leakage depth in cervical walls observed by micro-CT and microscope showed no significant difference; however, in certain cases the judgment of leakage depth in the occlusal wall in micro-CT image was affected by adjacent enamel structure, providing less leakage depth than was observed with the microscope (p<0.01). Micro-CT displayed the three-dimensional image of the leakage around the Class V restorations with clear borders only in the dentin region. It can be concluded that micro-CT can detect nondestructively the leakage around a resin composite restoration in two and three dimensions, with accuracy comparable to that of the conventional microscope method in the dentin region but with inferior accuracy in the enamel region.

Comparison of Bone Grafts From Various Donor Sites in Human Bone Specimens.

PubMed

Kamal, Mohammad; Gremse, Felix; Rosenhain, Stefanie; Bartella, Alexander K; Hölzle, Frank; Kessler, Peter; Lethaus, Bernd

2018-05-14

The objective of the current study was to compare the three-dimensional (3D) morphometric microstructure in human cadaveric bone specimens taken from various commonly utilized donor sites for autogenous bone grafting. Autogenous bone grafts can be harvested from various anatomic sites and express heterogeneous bone quality with a specific 3D microstructure for each site. The long-term structural integrity and susceptibility to resorption of the graft depend on the selected donor bone. Micro-computed tomography generates high-resolution datasets of bone structures and calcifications making this modality versatile for microarchitecture analysis and quantification of the bone. Six bone specimens, 10 mm in length, where anatomically possible, were obtained from various anatomical sites from 10 human dentate cadavers (4 men, 6 women, mean age 69.5 years). Specimens were scanned using a micro-computed tomography device and volumetrically reconstructed. A virtual cylindrical inclusion was reconstructed to analyze the bone mineral density and structural morphometric analysis using bone indices: relative bone volume, surface density, trabecular thicknesses, and trabecular separation. Calvarial bone specimens showed the highest mineral density, followed by the chin, then mandibular ramus then the tibia, whereas iliac crest and maxillary tuberosity had lower bone mineral densities. The pairwise comparison revealed statistically significant differences in the bone mineral density and relative bone volume index in the calvaria, mandibular ramus, mandibular symphysis groups when compared with those in the iliac crest and maxillary tuberosity, suggesting higher bone quality in the former groups than in the latter; tibial specimens expressed variable results.

Characterization of the porous structures of the green body and sintered biomedical titanium scaffolds with micro-computed tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arifvianto, B., E-mail: b.arifvianto@tudelft.nl; L

The present research was aimed at gaining an understanding of the porous structure changes from the green body through water leaching and sintering to titanium scaffolds. Micro-computed tomography (micro-CT) was performed to generate 3D models of titanium scaffold preforms containing carbamide space-holding particles and sintered scaffolds containing macro- and micro-pores. The porosity values and structural parameters were determined by means of image analysis. The result showed that the porosity values, macro-pore sizes, connectivity densities and specific surface areas of the titanium scaffolds sintered at 1200 °C for 3 h did not significantly deviate from those of the green structures withmore » various volume fractions of the space holder. Titanium scaffolds with a maximum specific surface area could be produced with an addition of 60–65 vol% carbamide particles to the matrix powder. The connectivity of pores inside the scaffold increased with rising volume fraction of the space holder. The shrinkage of the scaffolds prepared with > 50 vol% carbamide space holder, occurring during sintering, was caused by the reductions of macro-pore sizes and micro-pore sizes as well as the thickness of struts. In conclusion, the final porous structural characteristics of titanium scaffolds could be estimated from those of the green body. - Highlights: •Porous structures of green body and sintered titanium scaffolds was studied. •Porous structures of both samples were quantitatively characterized with micro-CT. •Porous structures of scaffolds could be controlled from the green body. •Shrinkage mechanisms of titanium scaffolds during sintering was established.« less

Synchrotron Radiation Microcomputed Tomography Guided Chromatographic Analysis for Displaying the Material Distribution in Tablets.

PubMed

Zhang, Liu; Wu, Li; Wang, Caifen; Zhang, Guoqing; Yu, Lin; Li, Haiyan; Maharjan, Abi; Tang, Yan; He, Dunwei; York, Peter; Sun, Huimin; Yin, Xianzhen; Zhang, Jiwen; Sun, Lixin

2018-03-06

One unusual and challenging scientific field that has received only cursory attention to date is the three-dimensional (3D) microstructure and spatial distribution of drug(s) and formulation materials in solid dosage forms. This study aims to provide deeper insight into the relationships between the microstructure of multiple-unit pellet system (MUPS) tablets and the spatial distribution of the active pharmaceutical ingredient (API) and excipients to facilitate the design of quantitative models for drug delivery systems. Synchrotron radiation X-ray microcomputed tomography (SR-μCT) was established as a 3D structure elucidation technique, which, in conjunction with liquid chromatography coupled to mass spectrometry (LC-MS) or liquid chromatography with evaporative light-scattering detector (LC-ELSD) enables chemical analysis of tablets. On the basis of the specific interior construction of theophylline MUPS tablets, the spatial distribution of materials was acquired by quantifying microregion samples that had been validated by SR-μCT for their locations in the MUPS tablets. The 3D structure of the MUPS tablets was catalogued as three structural domains: a matrix layer (ML), a protective cushion layer (PCL), and pellets (PL). Compared with the components in the ML, components in the PL had a larger proportion of theophylline, sucrose, and diethyl phthalate and a smaller proportion of lactose and sodium lauryl sulfate, whereas glyceryl monostearate was found to account for a large portion of the PCL. Microstructural characterization-guided zonal chemical determination represents a new approach for quality assessment and the development of drug delivery systems with in-depth insight into their constituent layers on a new scale.

Sine systemate chaos? A versatile tool for earthworm taxonomy: non-destructive imaging of freshly fixed and museum specimens using micro-computed tomography.

PubMed

Fernández, Rosa; Kvist, Sebastian; Lenihan, Jennifer; Giribet, Gonzalo; Ziegler, Alexander

2014-01-01

In spite of the high relevance of lumbricid earthworms ('Oligochaeta': Lumbricidae) for soil structure and functioning, the taxonomy of this group of terrestrial invertebrates remains in a quasi-chaotic state. Earthworm taxonomy traditionally relies on the interpretation of external and internal morphological characters, but the acquisition of these data is often hampered by tedious dissections or restricted access to valuable and rare museum specimens. The present state of affairs, in conjunction with the difficulty of establishing primary homologies for multiple morphological features, has led to an almost unrivaled instability in the taxonomy and systematics of certain earthworm groups, including Lumbricidae. As a potential remedy, we apply for the first time a non-destructive imaging technique to lumbricids and explore the future application of this approach to earthworm taxonomy. High-resolution micro-computed tomography (μCT) scanning of freshly fixed and museum specimens was carried out using two cosmopolitan species, Aporrectodea caliginosa and A. trapezoides. By combining two-dimensional and three-dimensional dataset visualization techniques, we demonstrate that the morphological features commonly used in earthworm taxonomy can now be analyzed without the need for dissection, whether freshly fixed or museum specimens collected more than 60 years ago are studied. Our analyses show that μCT in combination with soft tissue staining can be successfully applied to lumbricid earthworms. An extension of the approach to other families is poised to strengthen earthworm taxonomy by providing a versatile tool to resolve the taxonomic chaos currently present in this ecologically important, but taxonomically neglected group of terrestrial invertebrates.

Root canal preparation with a novel nickel-titanium instrument evaluated with micro-computed tomography: canal surface preparation over time.

PubMed

Peters, Ove A; Boessler, Claudia; Paqué, Frank

2010-06-01

The aim of this part of an ongoing study was to describe the dentin removal ability of a novel nickel-titanium instrument, the self-adjusting file (SAF), by using micro-computed tomography. Twenty maxillary incisors were scanned preoperatively at 20-microm resolution and postoperatively after up to 6 minutes of preparation with an SAF with 1.5-mm or 2-mm diameter. SAFs were operated with continuous irrigation in a handpiece that provided an oscillating, in-and-out movement. Changes in canal volume compared with preoperative values as well as unprepared canal surface area were determined. Data were normally distributed and compared by analysis of variance and regression analyses. Preoperatively canal volumes were statistically similar in both groups (9.86 +/- 3.97 mm3 and 9.80 +/- 2.67 mm3). Volumes increased during preparation to 13.58 +/- 3.85 mm3 (after 6 minutes with SAF 1.5 mm) and 16.43 +/- 3.64 mm3 (after 5 minutes with SAF 2.0 mm), and overall canal shapes were adequate. Unprepared canal surface area decreased from 63.0% +/- 15.1% (2 minutes with SAF 1.5 mm) to 8.6% +/- 4.1% (5 minutes with SAF 2.0 mm). Preparation of straight root canals in maxillary anterior teeth left little canal surface uninstrumented after shaping with the SAF. The timeframe of clinical application will depend on the amount of desired dentin removal and done with an SAF selected on the basis of apical gauging. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Sine Systemate Chaos? A Versatile Tool for Earthworm Taxonomy: Non-Destructive Imaging of Freshly Fixed and Museum Specimens Using Micro-Computed Tomography

PubMed Central

Fernández, Rosa; Kvist, Sebastian; Lenihan, Jennifer; Giribet, Gonzalo; Ziegler, Alexander

2014-01-01

In spite of the high relevance of lumbricid earthworms (‘Oligochaeta’: Lumbricidae) for soil structure and functioning, the taxonomy of this group of terrestrial invertebrates remains in a quasi-chaotic state. Earthworm taxonomy traditionally relies on the interpretation of external and internal morphological characters, but the acquisition of these data is often hampered by tedious dissections or restricted access to valuable and rare museum specimens. The present state of affairs, in conjunction with the difficulty of establishing primary homologies for multiple morphological features, has led to an almost unrivaled instability in the taxonomy and systematics of certain earthworm groups, including Lumbricidae. As a potential remedy, we apply for the first time a non-destructive imaging technique to lumbricids and explore the future application of this approach to earthworm taxonomy. High-resolution micro-computed tomography (μCT) scanning of freshly fixed and museum specimens was carried out using two cosmopolitan species, Aporrectodea caliginosa and A. trapezoides. By combining two-dimensional and three-dimensional dataset visualization techniques, we demonstrate that the morphological features commonly used in earthworm taxonomy can now be analyzed without the need for dissection, whether freshly fixed or museum specimens collected more than 60 years ago are studied. Our analyses show that μCT in combination with soft tissue staining can be successfully applied to lumbricid earthworms. An extension of the approach to other families is poised to strengthen earthworm taxonomy by providing a versatile tool to resolve the taxonomic chaos currently present in this ecologically important, but taxonomically neglected group of terrestrial invertebrates. PMID:24837238

Effects of increased apical enlargement on the amount of unprepared areas and coronal dentine removal: a micro-computed tomography study.

PubMed

Pérez, A R; Alves, F R F; Marceliano-Alves, M F; Provenzano, J C; Gonçalves, L S; Neves, A A; Siqueira, J F

2018-06-01

To evaluate the effects of progressive apical enlargement on the amount of unprepared root canal surface area and remaining dentine thickness. The root canals of 30 extracted mandibular incisors with Vertucci's type I configuration were instrumented with rotary HyFlex CM instruments (Coltene-Whaledent, Altstätten, Switzerland) up to 4 instruments larger than the first one that bound at the working length (WL). Teeth were scanned in a micro-computed tomography (micro-CT) device before canal preparation and after instrumentation with the 2nd, 3rd and 4th larger instruments. The amount of unprepared surface area in the full canal or in the apical 4 mm as well as the remaining dentine thickness at 10 mm from the WL were calculated and compared. The general linear model for repeated measures adjusted by Bonferroni's post hoc test was used for statistic analysis. There was a significant reduction in the amount of unprepared areas after each increase in preparation size (P < 0.01). This was observed for both the full canal length and the 4-mm apical segment. The amount of remaining dentine was also significantly reduced after each file size (P < 0.01). However, dentine thickness always remained greater than 1 mm, even after using the largest instrument. Apical preparations up to 4 instruments larger than the first one to bind at the WL caused a significant progressive reduction in the unprepared canal area. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Shape and Size of Microfine Aggregates: X-ray Microcomputed Tomgraphy vs. Laser Diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erdogan,S.; Garboczi, E.; Fowler, D.

Microfine rock aggregates, formed naturally or in a crushing process, pass a No. 200 ASTM sieve, so have at least two orthogonal principal dimensions less than 75 {mu}m, the sieve opening size. In this paper, for the first time, we capture true 3-D shape and size data of several different types of microfine aggregates, using X-ray microcomputed tomography ({mu}CT) with a voxel size of 2 {mu}m. This information is used to generate shape analyses of various kinds. Particle size distributions are also generated from the {mu}CT data and quantitatively compared to the results of laser diffraction, which is the leadingmore » method for measuring particle size distributions of sub-millimeter size particles. By taking into account the actual particle shape, the differences between {mu}CT and laser diffraction can be qualitatively explained.« less

Micro-Computed Tomography Assessment of Fracture Healing: Relationships among Callus Structure, Composition, and Mechanical Function

PubMed Central

Morgan, Elise F.; Mason, Zachary D.; Chien, Karen B.; Pfeiffer, Anthony J.; Barnes, George L.; Einhorn, Thomas A.; Gerstenfeld, Louis C.

2009-01-01

Non-invasive characterization of fracture callus structure and composition may facilitate development of surrogate measures of the regain of mechanical function. As such, quantitative computed tomography- (CT-) based analyses of fracture calluses could enable more reliable clinical assessments of bone healing. Although previous studies have used CT to quantify and predict fracture healing, it is unclear which of the many CT-derived metrics of callus structure and composition are the most predictive of callus mechanical properties. The goal of this study was to identify the changes in fracture callus structure and composition that occur over time and that are most closely related to the regain of mechanical function. Micro-computed tomography (μCT) imaging and torsion testing were performed on murine fracture calluses (n=188) at multiple post-fracture timepoints and under different experimental conditions that alter fracture healing. Total callus volume (TV), mineralized callus volume (BV), callus mineralized volume fraction (BV/TV), bone mineral content (BMC), tissue mineral density (TMD), standard deviation of mineral density (σTMD), effective polar moment of inertia (Jeff), torsional strength, and torsional rigidity were quantified. Multivariate statistical analyses, including multivariate analysis of variance, principal components analysis, and stepwise regression were used to identify differences in callus structure and composition among experimental groups and to determine which of the μCT outcome measures were the strongest predictors of mechanical properties. Although calluses varied greatly in the absolute and relative amounts of mineralized tissue (BV, BMC, and BV/TV), differences among timepoints were most strongly associated with changes in tissue mineral density. Torsional strength and rigidity were dependent on mineral density as well as the amount of mineralized tissue: TMD, BV, and σTMD explained 62% of the variation in torsional strength (p<0.001); and TMD, BMC, BV/TV, and σTMD explained 70% of the variation in torsional rigidity (p<0.001). These results indicate that fracture callus mechanical properties can be predicted by several μCT-derived measures of callus structure and composition. These findings form the basis for developing non-invasive assessments of fracture healing and for identifying biological and biomechanical mechanisms that lead to impaired or enhanced healing. PMID:19013264

Micro-Computed Tomography Evaluation of Human Fat Grafts in Nude Mice

PubMed Central

Chung, Michael T.; Hyun, Jeong S.; Lo, David D.; Montoro, Daniel T.; Hasegawa, Masakazu; Levi, Benjamin; Januszyk, Michael; Longaker, Michael T.

2013-01-01

Background Although autologous fat grafting has revolutionized the field of soft tissue reconstruction and augmentation, long-term maintenance of fat grafts is unpredictable. Recent studies have reported survival rates of fat grafts to vary anywhere between 10% and 80% over time. The present study evaluated the long-term viability of human fat grafts in a murine model using a novel imaging technique allowing for in vivo volumetric analysis. Methods Human fat grafts were prepared from lipoaspirate samples using the Coleman technique. Fat was injected subcutaneously into the scalp of 10 adult Crl:NU-Foxn1nu CD-1 male mice. Micro-computed tomography (CT) was performed immediately following injection and then weekly thereafter. Fat volume was rendered by reconstructing a three-dimensional (3D) surface through cubic-spline interpolation. Specimens were also harvested at various time points and sections were prepared and stained with hematoxylin and eosin (H&E), for macrophages using CD68 and for the cannabinoid receptor 1 (CB1). Finally, samples were explanted at 8- and 12-week time points to validate calculated micro-CT volumes. Results Weekly CT scanning demonstrated progressive volume loss over the time course. However, volumetric analysis at the 8- and 12-week time points stabilized, showing an average of 62.2% and 60.9% survival, respectively. Gross analysis showed the fat graft to be healthy and vascularized. H&E analysis and staining for CD68 showed minimal inflammatory reaction with viable adipocytes. Immunohistochemical staining with anti-human CB1 antibodies confirmed human origin of the adipocytes. Conclusions Studies assessing the fate of autologous fat grafts in animals have focused on nonimaging modalities, including histological and biochemical analyses, which require euthanasia of the animals. In this study, we have demonstrated the ability to employ micro-CT for 3D reconstruction and volumetric analysis of human fat grafts in a mouse model. Importantly, this model provides a platform for subsequent study of fat manipulation and soft tissue engineering. PMID:22916732

Cell Invasion in Collagen Scaffold Architectures Characterized by Percolation Theory.

PubMed

Ashworth, Jennifer C; Mehr, Marco; Buxton, Paul G; Best, Serena M; Cameron, Ruth E

2015-06-24

The relationship between biological scaffold interconnectivity and cell migration is an important but poorly understood factor in tissue regeneration. Here a scale-independent technique for characterization of collagen scaffold interconnectivity is presented, using a combination of X-ray microcomputed tomography and percolation theory. Confocal microscopy of connective tissue cells reveals this technique as highly relevant for determining the extent of cell invasion. © 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cochlear implant-related three-dimensional characteristics determined by micro-computed tomography reconstruction.

PubMed

Ni, Yusu; Dai, Peidong; Dai, Chunfu; Li, Huawei

2017-01-01

To explore the structural characteristics of the cochlea in three-dimensional (3D) detail using 3D micro-computed tomography (mCT) image reconstruction of the osseous labyrinth, with the aim of improving the structural design of electrodes, the selection of stimulation sites, and the effectiveness of cochlear implantation. Three temporal bones were selected from among adult donors' temporal bone specimens. A micro-CT apparatus (GE eXplore) was used to scan three specimens with a voxel resolution of 45 μm. We obtained about 460 slices/specimen, which produced abundant data. The osseous labyrinth images of three specimens were reconstructed from mCT. The cochlea and its spiral characteristics were measured precisely using Able Software 3D-DOCTOR. The 3D images of the osseous labyrinth, including the cochlea, vestibule, and semicircular canals, were reconstructed. The 3D models of the cochlea showed the spatial relationships and surface structural characteristics. Quantitative data concerning the cochlea and its spiral structural characteristics were analyzed with regard to cochlear implantation. The 3D reconstruction of mCT images clearly displayed the detailed spiral structural characteristics of the osseous labyrinth. Quantitative data regarding the cochlea and its spiral structural characteristics could help to improve electrode structural design, signal processing, and the effectiveness of cochlear implantation. Clin. Anat. 30:39-43, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Influence of peri-implant artifacts on bone morphometric analysis with micro-computed tomography.

PubMed

Song, Jin Wook; Cha, Jung Yul; Bechtold, Till Edward; Park, Young Chel

2013-01-01

To determine the optimal dilation pixel size distance from the mini-implant interface needed to compensate for the metal artifact on micro-computed tomography (micro-CT) for bone morphometric analysis. A total of 72 self-drilling mini-implants were placed into the buccal alveolar bone of six male beagle dogs. After 12 weeks of orthodontic loading, specimens were harvested and scanned with micro-CT (Skyscan 1076) at a resolution of 9 μm. Using the reload plug-in and dilation procedure of CTAn, the percentage of bone-implant contact (BIC) and bone volume density (BV/TV, bone volume/total volume), respectively, were measured from one to seven pixels from the metal implant surface. Each pixel size of dilation (PSD) were compared with that of a ground histologic section, and the optimal PSD for bone morphometric analysis using micro-CT was determined. BIC values from micro-CT analysis decreased when the PSD increased (P < .05). BIC from micro-CT showed the highest correlation coefficient with BIC from histologic slides when the PSD was 5 to 7 (P < .05), whereas BV/TV from micro-CT showed a very high correlation with BV/TV from histologic slides in all ranges (P < .0001). To measure BIC and BV/TV using micro-CT, at least 5 PSD from the metal implant surface is needed.

Fracture healing using degradable magnesium fixation plates and screws.

PubMed

Chaya, Amy; Yoshizawa, Sayuri; Verdelis, Kostas; Noorani, Sabrina; Costello, Bernard J; Sfeir, Charles

2015-02-01

Internal bone fixation devices made with permanent metals are associated with numerous long-term complications and may require removal. We hypothesized that fixation devices made with degradable magnesium alloys could provide an ideal combination of strength and degradation, facilitating fracture fixation and healing while eliminating the need for implant removal surgery. Fixation plates and screws were machined from 99.9% pure magnesium and compared with titanium devices in a rabbit ulnar fracture model. Magnesium device degradation and the effect on fracture healing and bone formation were assessed after 4 weeks. Fracture healing with magnesium device fixation was compared with that of titanium devices using qualitative histologic analysis and quantitative histomorphometry. Micro-computed tomography showed device degradation after 4 weeks in vivo. In addition, 2-dimensional micro-computed tomography slices and histologic staining showed that magnesium degradation did not inhibit fracture healing or bone formation. Histomorphology showed no difference in bone-bridging fractures fixed with magnesium and titanium devices. Interestingly, abundant new bone was formed around magnesium devices, suggesting a connection between magnesium degradation and bone formation. Our results show potential for magnesium fixation devices in a loaded fracture environment. Furthermore, these results suggest that magnesium fixation devices may enhance fracture healing by encouraging localized new bone formation. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Virtual forensic entomology: improving estimates of minimum post-mortem interval with 3D micro-computed tomography.

PubMed

Richards, Cameron S; Simonsen, Thomas J; Abel, Richard L; Hall, Martin J R; Schwyn, Daniel A; Wicklein, Martina

2012-07-10

We demonstrate how micro-computed tomography (micro-CT) can be a powerful tool for describing internal and external morphological changes in Calliphora vicina (Diptera: Calliphoridae) during metamorphosis. Pupae were sampled during the 1st, 2nd, 3rd and 4th quarter of development after the onset of pupariation at 23 °C, and placed directly into 80% ethanol for preservation. In order to find the optimal contrast, four batches of pupae were treated differently: batch one was stained in 0.5M aqueous iodine for 1 day; two for 7 days; three was tagged with a radiopaque dye; four was left unstained (control). Pupae stained for 7d in iodine resulted in the best contrast micro-CT scans. The scans were of sufficiently high spatial resolution (17.2 μm) to visualise the internal morphology of developing pharate adults at all four ages. A combination of external and internal morphological characters was shown to have the potential to estimate the age of blowfly pupae with a higher degree of accuracy and precision than using external morphological characters alone. Age specific developmental characters are described. The technique could be used as a measure to estimate a minimum post-mortem interval in cases of suspicious death where pupae are the oldest stages of insect evidence collected. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Microcomputed tomography and microfinite element modeling for evaluating polymer scaffolds architecture and their mechanical properties.

PubMed

Alberich-Bayarri, Angel; Moratal, David; Ivirico, Jorge L Escobar; Rodríguez Hernández, José C; Vallés-Lluch, Ana; Martí-Bonmatí, Luis; Estellés, Jorge Más; Mano, Joao F; Pradas, Manuel Monleón; Ribelles, José L Gómez; Salmerón-Sánchez, Manuel

2009-10-01

Detailed knowledge of the porous architecture of synthetic scaffolds for tissue engineering, their mechanical properties, and their interrelationship was obtained in a nondestructive manner. Image analysis of microcomputed tomography (microCT) sections of different scaffolds was done. The three-dimensional (3D) reconstruction of the scaffold allows one to quantify scaffold porosity, including pore size, pore distribution, and struts' thickness. The porous morphology and porosity as calculated from microCT by image analysis agrees with that obtained experimentally by scanning electron microscopy and physically measured porosity, respectively. Furthermore, the mechanical properties of the scaffold were evaluated by making use of finite element modeling (FEM) in which the compression stress-strain test is simulated on the 3D structure reconstructed from the microCT sections. Elastic modulus as calculated from FEM is in agreement with those obtained from the stress-strain experimental test. The method was applied on qualitatively different porous structures (interconnected channels and spheres) with different chemical compositions (that lead to different elastic modulus of the base material) suitable for tissue regeneration. The elastic properties of the constructs are explained on the basis of the FEM model that supports the main mechanical conclusion of the experimental results: the elastic modulus does not depend on the geometric characteristics of the pore (pore size, interconnection throat size) but only on the total porosity of the scaffold. (c) 2009 Wiley Periodicals, Inc.

Microcomputed tomographic and histologic analysis of anorganic bone matrix coupled with cell-binding peptide suspended in sodium hyaluronate carrier after sinus augmentation: a clinical study.

PubMed

Emam, Hany; Beheiri, Galal; Elsalanty, Mohammed; Sharawy, Mohamed

2011-01-01

Anorganic bovine hydroxyapatite matrix (ABM), when coupled with synthetic cell-binding peptide (P15), mimics the cell-binding region of type 1 collagen and is commercially available suspended in a sodium hyaluronate carrier. The aim of the present study, therefore, was to test the efficacy of ABM/P-15 Putty (DENTSPLY Friadent CeraMed) as a sole graft material for sinus augmentation in patients with severely resorbed posterior maxillae. Sinus augmentation was performed in 10 patients using ABM/P-15 Putty and two provisional dental implants (3.0 mm in diameter). The graft and implants were placed simultaneously with the aid of a surgical stent. After 8 or 16 weeks, the implants were removed using a 4.25-mm trephine bur; this was followed by immediate placement of wider-diameter (5.5-mm) implants. All 20 implants were scanned by microcomputed tomography to determine bone mineral density (BMD), percent bone volume (PBV), and percent bone contact (PBC). There was a significant increase in the BMD of bone around the implants at 8 weeks and 16 weeks compared to native residual (control) bone. There was no significant difference in PBV or PBC between 8 weeks and 16 weeks. The average increase in bone height at 16 weeks was 9.63 ± 1 mm. Microcomputed tomographic images and histologic sections showed dense graft particles surrounded by vital trabecular bone. BMD increases as early as 8 weeks and does not show an additional increase after 16 weeks. PepGen P-15 Putty was found to be a promising osteoconductive graft for sinus augmentation, supporting immediate placement of implants.

Shaping ability of the conventional nickel-titanium and reciprocating nickel-titanium file systems: a comparative study using micro-computed tomography.

PubMed

Hwang, Young-Hye; Bae, Kwang-Shik; Baek, Seung-Ho; Kum, Kee-Yeon; Lee, WooCheol; Shon, Won-Jun; Chang, Seok Woo

2014-08-01

This study used micro-computed tomographic imaging to compare the shaping ability of Mtwo (VDW, Munich, Germany), a conventional nickel-titanium file system, and Reciproc (VDW), a reciprocating file system morphologically similar to Mtwo. Root canal shaping was performed on the mesiobuccal and distobuccal canals of extracted maxillary molars. In the RR group (n = 15), Reciproc was used in a reciprocating motion (150° counterclockwise/30° clockwise, 300 rpm); in the MR group, Mtwo was used in a reciprocating motion (150° clockwise/30° counterclockwise, 300 rpm); and in the MC group, Mtwo was used in a continuous rotating motion (300 rpm). Micro-computed tomographic images taken before and after canal shaping were used to analyze canal volume change and the degree of transportation at the cervical, middle, and apical levels. The time required for canal shaping was recorded. Afterward, each file was analyzed using scanning electron microscopy. No statistically significant differences were found among the 3 groups in the time for canal shaping or canal volume change (P > .05). Transportation values of the RR and MR groups were not significantly different at any level. However, the transportation value of the MC group was significantly higher than both the RR and MR groups at the cervical and apical levels (P < .05). In the scanning electron microscopic analysis, file deformation was observed for 1 file in group RR (1/15), 3 files in group MR (3/15), and 5 files in group MC (5/15). In terms of shaping ability, Mtwo used in a reciprocating motion was not significantly different from the Reciproc system. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Chitosan nanofiber scaffold improves bone healing via stimulating trabecular bone production due to upregulation of the Runx2/osteocalcin/alkaline phosphatase signaling pathway

PubMed Central

Ho, Ming-Hua; Yao, Chih-Jung; Liao, Mei-Hsiu; Lin, Pei-I; Liu, Shing-Hwa; Chen, Ruei-Ming

2015-01-01

Osteoblasts play critical roles in bone formation. Our previous study showed that chitosan nanofibers can stimulate osteoblast proliferation and maturation. This translational study used an animal model of bone defects to evaluate the effects of chitosan nanofiber scaffolds on bone healing and the possible mechanisms. In this study, we produced uniform chitosan nanofibers with fiber diameters of approximately 200 nm. A bone defect was surgically created in the proximal femurs of male C57LB/6 mice, and then the left femur was implanted with chitosan nanofiber scaffolds for 21 days and compared with the right femur, which served as a control. Histological analyses revealed that implantation of chitosan nanofiber scaffolds did not lead to hepatotoxicity or nephrotoxicity. Instead, imaging analyses by X-ray transmission and microcomputed tomography showed that implantation of chitosan nanofiber scaffolds improved bone healing compared with the control group. In parallel, microcomputed tomography and bone histomorphometric assays further demonstrated augmentation of the production of new trabecular bone in the chitosan nanofiber-treated group. Furthermore, implantation of chitosan nanofiber scaffolds led to a significant increase in the trabecular bone thickness but a reduction in the trabecular parameter factor. As to the mechanisms, analysis by confocal microscopy showed that implantation of chitosan nanofiber scaffolds increased levels of Runt-related transcription factor 2 (Runx2), a key transcription factor that regulates osteogenesis, in the bone defect sites. Successively, amounts of alkaline phosphatase and osteocalcin, two typical biomarkers that can simulate bone maturation, were augmented following implantation of chitosan nanofiber scaffolds. Taken together, this translational study showed a beneficial effect of chitosan nanofiber scaffolds on bone healing through stimulating trabecular bone production due to upregulation of Runx2-mediated alkaline phosphatase and osteocalcin gene expressions. Our results suggest the potential of chitosan nanofiber scaffolds for therapy of bone diseases, including bone defects and bone fractures. PMID:26451104

Mineral distributions at the developing tendon enthesis.

PubMed

Schwartz, Andrea G; Pasteris, Jill D; Genin, Guy M; Daulton, Tyrone L; Thomopoulos, Stavros

2012-01-01

Tendon attaches to bone across a functionally graded interface, "the enthesis". A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM). A zone (∼20 µm) exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked to endochondral bone formation near the tendon insertion. These conserved and time-varying aspects of interface composition may have important implications for the growth and mechanical stability of the tendon-to-bone attachment throughout development.

Performance of hybrid system for fluorescence and micro-computed tomography in synchronous mode

NASA Astrophysics Data System (ADS)

Liu, Xin; Zhang, Yi; Liu, Fei; Guo, Xiaolian; Wang, Xin; Bai, Jing

2010-11-01

Fluorescence diffuse optical tomography (FDOT) plays an important role in studying physiological and pathological processes of small animals in vivo. The low spatial resolution, however, limits the ability of FDOT in resolving the biodistributions of fluorescent markers. The anatomical information provided by X-ray computed tomography (CT) can be used to improve the image quality of FDOT. However, in most hybrid FDOT/CT systems, the projection data sets of optics and X-ray are acquired sequentially, which increases the acquisition time and bring in the unwanted soft tissue displacement. In this paper, we evaluate the performance of a synchronous FDOT/CT system, which allows for faster and concurrent imaging. Compared with previous FDOT/CT systems, the two subsystems (FDOT and CT) acquire projection images in synchronous mode, so the body position can keep consistent in the same projection data acquired by both subsystems. The experimental results of phantom and in vivo experiments suggest that the reconstruction quality of FDOT can be significantly improved when structural a priori information is utilized to constrain the reconstruction process. On the other hand, the synchronous FDOT/CT system decreases the imaging time.

Noninvasive imaging of experimental lung fibrosis.

PubMed

Zhou, Yong; Chen, Huaping; Ambalavanan, Namasivayam; Liu, Gang; Antony, Veena B; Ding, Qiang; Nath, Hrudaya; Eary, Janet F; Thannickal, Victor J

2015-07-01

Small animal models of lung fibrosis are essential for unraveling the molecular mechanisms underlying human fibrotic lung diseases; additionally, they are useful for preclinical testing of candidate antifibrotic agents. The current end-point measures of experimental lung fibrosis involve labor-intensive histological and biochemical analyses. These measures fail to account for dynamic changes in the disease process in individual animals and are limited by the need for large numbers of animals for longitudinal studies. The emergence of noninvasive imaging technologies provides exciting opportunities to image lung fibrosis in live animals as often as needed and to longitudinally track the efficacy of novel antifibrotic compounds. Data obtained by noninvasive imaging provide complementary information to histological and biochemical measurements. In addition, the use of noninvasive imaging in animal studies reduces animal usage, thus satisfying animal welfare concerns. In this article, we review these new imaging modalities with the potential for evaluation of lung fibrosis in small animal models. Such techniques include micro-computed tomography (micro-CT), magnetic resonance imaging, positron emission tomography (PET), single photon emission computed tomography (SPECT), and multimodal imaging systems including PET/CT and SPECT/CT. It is anticipated that noninvasive imaging will be increasingly used in animal models of fibrosis to gain insights into disease pathogenesis and as preclinical tools to assess drug efficacy.

Development of computational small animal models and their applications in preclinical imaging and therapy research.

PubMed

Xie, Tianwu; Zaidi, Habib

2016-01-01

The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and the development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.

Image-guided tissue engineering of anatomically shaped implants via MRI and micro-CT using injection molding.

PubMed

Ballyns, Jeffery J; Gleghorn, Jason P; Niebrzydowski, Vicki; Rawlinson, Jeremy J; Potter, Hollis G; Maher, Suzanne A; Wright, Timothy M; Bonassar, Lawrence J

2008-07-01

This study demonstrates for the first time the development of engineered tissues based on anatomic geometries derived from widely used medical imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). Computer-aided design and tissue injection molding techniques have demonstrated the ability to generate living implants of complex geometry. Due to its complex geometry, the meniscus of the knee was used as an example of this technique's capabilities. MRI and microcomputed tomography (microCT) were used to design custom-printed molds that enabled the generation of anatomically shaped constructs that retained shape throughout 8 weeks of culture. Engineered constructs showed progressive tissue formation indicated by increases in extracellular matrix content and mechanical properties. The paradigm of interfacing tissue injection molding technology can be applied to other medical imaging techniques that render 3D models of anatomy, demonstrating the potential to apply the current technique to engineering of many tissues and organs.

Comparison of the accuracy of 3-dimensional cone-beam computed tomography and micro-computed tomography reconstructions by using different voxel sizes.

PubMed

Maret, Delphine; Peters, Ove A; Galibourg, Antoine; Dumoncel, Jean; Esclassan, Rémi; Kahn, Jean-Luc; Sixou, Michel; Telmon, Norbert

2014-09-01

Cone-beam computed tomography (CBCT) data are, in principle, metrically exact. However, clinicians need to consider the precision of measurements of dental morphology as well as other hard tissue structures. CBCT spatial resolution, and thus image reconstruction quality, is restricted by the acquisition voxel size. The aim of this study was to assess geometric discrepancies among 3-dimensional CBCT reconstructions relative to the micro-CT reference. A total of 37 permanent teeth from 9 mandibles were scanned with CBCT 9500 and 9000 3D and micro-CT. After semiautomatic segmentation, reconstructions were obtained from CBCT acquisitions (voxel sizes 76, 200, and 300 μm) and from micro-CT (voxel size 41 μm). All reconstructions were positioned in the same plane by image registration. The topography of the geometric discrepancies was displayed by using a color map allowing the maximum differences to be located. The maximum differences were mainly found at the cervical margins and on the cusp tips or incisal edges. Geometric reconstruction discrepancies were significant at 300-μm resolution (P = .01, Wilcoxon test). To study hard tissue morphology, CBCT acquisitions require voxel sizes smaller than 300 μm. This experimental study will have to be complemented by studies in vivo that consider the conditions of clinical practice. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Novel self-gelling injectable hydrogel/alpha-tricalcium phosphate composites for bone regeneration: Physiochemical and microcomputer tomographical characterization.

PubMed

Douglas, Timothy E L; Schietse, Josefien; Zima, Aneta; Gorodzha, Svetlana; Parakhonskiy, Bogdan V; KhaleNkow, Dmitry; Shkarin, Roman; Ivanova, Anna; Baumbach, Tilo; Weinhardt, Venera; Stevens, Christian V; Vanhoorne, Valérie; Vervaet, Chris; Balcaen, Lieve; Vanhaecke, Frank; Slośarczyk, Anna; Surmeneva, Maria A; Surmenev, Roman A; Skirtach, Andre G

2018-03-01

Mineralized hydrogels are increasingly gaining attention as biomaterials for bone regeneration. The most common mineralization strategy has been addition of preformed inorganic particles during hydrogel formation. This maintains injectability. One common form of bone cement is formed by mixing particles of the highly reactive calcium phosphate alpha-tricalcium phosphate (α-TCP) with water to form hydroxyapatite (HA). The calcium ions released during this reaction can be exploited to crosslink anionic, calcium-binding polymers such as the polysaccharide gellan gum (GG) to induce hydrogel formation. In this study, three different amounts of α-TCP particles were added to GG polymer solution to generate novel, injectable hydrogel-inorganic composites. Distribution of the inorganic phase in the hydrogel was studied by high resolution microcomputer tomography (µCT). Gelation occurred within 30 min. α-TCP converted to HA. µCT revealed inhomogeneous distribution of the inorganic phase in the composites. These results demonstrate the potential of the composites as alternatives to traditional α-TCP bone cement and pave the way for incorporation of biologically active substances and in vitro and in vivo testing. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 822-828, 2018. © 2017 Wiley Periodicals, Inc.

Restrain of bone growth by estrogen-mimetic peptide-1 (EMP-1): a micro-computed tomographic study.

PubMed

Kasher, Roni; Bajayo, Alon; Gabet, Yankel; Nevo, Nava; Fridkin, Mati; Katchalski-Katzir, Ephraim; Kohen, Fortune; Bab, Itai

2009-06-01

Estrogen has a key role in the regulation of skeletal growth and maintenance of bone mass. Recently, we developed peptides having estrogen-like activity as potential estrogen-based new drugs. The aim of the present study was to evaluate the influence of long-term administration of the most efficacious of these peptides, the hexapeptide EMP-1 (VSWFFE), on bone mass and development. EMP-1 was injected daily to ovariectomized (OVX) and intact young, sexually mature female mice for 10 weeks. Whole femora, including the cartilaginous growth plates were analyzed by micro-computed tomography (microCT). We found that peptide EMP-1 restrains bone growth in OVX mice: it inhibited dramatically bone longitudinal growth (40%), and decreased femoral diaphyseal diameter. Peptide EMP-1 had no effect on bone growth in normal mice, and did not influence the OVX-induced bone loss. We then developed a new microCT methodology to evaluate uncalcified and calcified growth plate parameters. In the OVX mice, peptide EMP-1 reduced volume and thickness of the uncalcified growth plate, a possible cause for the inhibition of bone longitudinal growth. Peptide EMP-1 may be used as a lead compound for the development of drugs to treat acromegalic patients.

Analysis of mandibular second molars with fused roots and shallow radicular grooves by using micro-computed tomography.

PubMed

Amoroso-Silva, Pablo; De Moraes, Ivaldo Gomes; Marceliano-Alves, Marilia; Bramante, Clovis Monteiro; Zapata, Ronald Ordinola; Hungaro Duarte, Marco Antonio

2018-01-01

This study aimed to describe the morphological and morphometric aspects of fused mandibular second molars with radicular shallow grooves using micro-computed tomography (CT). Eighty-eight mandibular second molars with fused roots were scanned in a micro-CT scanner at a voxel size of 19.6 μm. After reconstruction, only molars without C-shaped roots and presenting shallow radicular grooves were selected. 30 molars were chosen for further analysis. Canal cross-sections were classified according to Fan's modified classification (C1, C2, C3, and C4) and morphometric parameters at the apical region, examination of accessory foramina and tridimensional configuration were evaluated. Three-dimensional reconstructions indicated a higher prevalence of merging type ( n = 22). According to Fan's modified classification, the C4 configuration was predominant in the 3 apical mm. Roundness median values revealed a more round-shaped canals at 3 mm (0.72) than at 2 (0.63) and 1 (0.61) mm from the apex. High values of major and minor diameters were observed in the canals of these evaluated sections. In addition, few accessory apical foramina were observed at 1 and 2 mm from the apex. The average distance between last accessory foramina and the anatomic apex was 1.17 mm. A less complex internal anatomy is found when a mandibular second molar presents fused roots with shallow radicular grooves. The merging type canal was frequently observed. Moreover, the C4 configuration was predominant at a point 3 mm from the apex and presented rounded canals, large apical diameters, and few accessory foramina. The cervical and middle thirds presented C3 and C1 canal configurations most frequently. A minor morphological complexity is found when fused mandibular second molars present shallow radicular grooves.

Repeated irradiation from micro-computed tomography scanning at 2, 4 and 6 months of age does not induce damage to tibial bone microstructure in male and female CD-1 mice.

PubMed

Sacco, Sandra M; Saint, Caitlin; Longo, Amanda B; Wakefield, Charles B; Salmon, Phil L; LeBlanc, Paul J; Ward, Wendy E

2017-01-01

Long-term effects of repeated i n vivo micro-computed tomography (μCT) scanning at key stages of growth and bone development (ages 2, 4 and 6 months) on trabecular and cortical bone structure, as well as developmental patterns, have not been studied. We determined the effect of repetitive μCT scanning at age 2, 4 and 6 months on tibia bone structure of male and female CD-1 mice and characterized developmental changes. At 2, 4 and 6 months of age, right tibias were scanned using in vivo μCT (Skyscan 1176) at one of three doses of radiation per scan: 222, 261 or 460 mGy. Left tibias of the same mice were scanned only at 6 months to serve as non-irradiated controls to determine whether recurrent radiation exposure alters trabecular and cortical bone structure at the proximal tibia. In males, eccentricity was lower ( P <0.05) in irradiated compared with non-irradiated tibias (222 mGy group). Within each sex, all other structural outcomes were similar between irradiated and non-irradiated tibias regardless of dose. Trabecular bone loss occurred in all mice due to age while cortical development continued to age 6 months. In conclusion, repetitive μCT scans at various radiation doses did not damage trabecular or cortical bone structure of proximal tibia in male and female CD-1 mice. Moreover, scanning at 2, 4 and 6 months of age highlight the different developmental time course between trabecular and cortical bone. These scanning protocols can be used to investigate longitudinal responses of bone structures to an intervention.

Quantification of experimental venous thrombus resolution by longitudinal nanogold-enhanced micro-computed tomography.

PubMed

Grover, Steven P; Saha, Prakash; Jenkins, Julia; Mukkavilli, Arun; Lyons, Oliver T; Patel, Ashish S; Sunassee, Kavitha; Modarai, Bijan; Smith, Alberto

2015-12-01

The assessment of thrombus size following treatments directed at preventing thrombosis or enhancing its resolution has generally relied on physical or histological methods. This cross-sectional design imposes the need for increased numbers of animals for experiments. Micro-computed tomography (microCT) has been used to detect the presence of venous thrombus in experimental models but has yet to be used in a quantitative manner. In this study, we investigate the use of contrast-enhanced microCT for the longitudinal assessment of experimental venous thrombus resolution. Thrombi induced by stenosis of the inferior vena cava in mice were imaged by contrast-enhanced microCT at 1, 7 and 14 days post-induction (n=18). Thrombus volumes were determined longitudinally by segmentation and 3D volume reconstruction of microCT scans and by standard end-point histological analysis at day 14. An additional group of thrombi were analysed solely by histology at 1, 7 and 14 days post-induction (n=15). IVC resident thrombus was readily detectable by contrast-enhanced microCT. MicroCT-derived measurements of thrombus volume correlated well with time-matched histological analyses (ICC=0.75, P<0.01). Thrombus volumes measured by microCT were significantly greater than those derived from histological analysis (P<0.001). Intra- and inter-observer analyses were highly correlated (ICC=0.99 and 0.91 respectively, P<0.0001). Further histological analysis revealed noticeable levels of contrast agent extravasation into the thrombus that was associated with the presence of neovascular channels, macrophages and intracellular iron deposits. Contrast-enhanced microCT represents a reliable and reproducible method for the longitudinal assessment of venous thrombus resolution providing powerful paired data. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Coronary artery wall imaging in mice using osmium tetroxide and micro-computed tomography (micro-CT).

PubMed

Pai, Vinay M; Kozlowski, Megan; Donahue, Danielle; Miller, Elishiah; Xiao, Xianghui; Chen, Marcus Y; Yu, Zu-Xi; Connelly, Patricia; Jeffries, Kenneth; Wen, Han

2012-05-01

The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary artery disease models, it is highly desirable to image coronary artery walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO(4) ) solution. As a tissue-staining contrast agent, OsO(4) is retained in the vessel wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the artery wall visible in CT. Additionally, since OsO(4) preferentially binds to lipids, it highlights lipid deposition in the artery wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE(-/-) ) mice at 10 μm resolution. The results show that walls of coronary arteries as small as 45 μm in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO(4) and micro-CT permits the visualization of the coronary artery wall in intact mouse hearts. Published 2012. This article is a US Government work and is in the public domain in the USA. Journal of Anatomy © 2012 Anatomical Society.

Microcomputed tomography and shock microdeformation studies on shatter cones

NASA Astrophysics Data System (ADS)

Zaag, Patrice Tristan; Reimold, Wolf Uwe; Hipsley, Christy Anna

2016-08-01

One of the aspects of impact cratering that are still not fully understood is the formation of shatter cones and related fracturing phenomena. Yet, shatter cones have been applied as an impact-diagnostic criterion for decades without the role of shock waves and target rock defects in their formation having been elucidated ever. We have tested the application of the nondestructive microcomputed tomography (μCT) method to visualize the interior of shatter cones in order to possibly resolve links between fracture patterns and shatter cone surface features (striations and intervening "valleys"). Shatter-coned samples from different impact sites and in different lithologies were investigated for their μCT suitability, with a shatter cone in sandstone from the Serra da Cangalha impact structure (Brazil) remaining as the most promising candidate because of the fracture resolution achieved. To validate the obtained CT data, the scanned specimen was cut into three orthogonal sets of thin sections. Scans with 13 μm resolution were obtained. μCT scans and microscopic analysis unraveled an orientation of subplanar fractures and related fluid inclusion trails, and planar fracture (PF) orientations in the interior of shatter cones. Planar deformation features (PDF) were observed predominantly near the shatter cone surface. Previously undescribed varieties of feather features (FF), in the form of lamellae emanating from curviplanar and curved fractures, as well as an "arrowhead"-like FF development with microlamellae originating from both sides of a PF, were observed. The timing of shatter cone formation was investigated by establishing temporal relations to the generation of various shock microscopic effects. Shatter cones are, thus, generated post- or syn-formation of PF, FF, subplanar fractures, and PDF. The earliest possible time for shatter cone formation is during the late stage of the compressional phase, that is, shock wave passage, of an impact event.

Bone matrix, cellularity, and structural changes in a rat model with high-turnover osteoporosis induced by combined ovariectomy and a multiple-deficient diet.

PubMed

Govindarajan, Parameswari; Böcker, Wolfgang; El Khassawna, Thaqif; Kampschulte, Marian; Schlewitz, Gudrun; Huerter, Britta; Sommer, Ursula; Dürselen, Lutz; Ignatius, Anita; Bauer, Natali; Szalay, Gabor; Wenisch, Sabine; Lips, Katrin S; Schnettler, Reinhard; Langheinrich, Alexander; Heiss, Christian

2014-03-01

In estrogen-deficient, postmenopausal women, vitamin D and calcium deficiency increase osteoporotic fracture risk. Therefore, a new rat model of combined ovariectomy and multiple-deficient diet was established to mimic human postmenopausal osteoporotic conditions under nutrient deficiency. Sprague-Dawley rats were untreated (control), laparatomized (sham), or ovariectomized and received a deficient diet (OVX-Diet). Multiple analyses involving structure (micro-computed tomography and biomechanics), cellularity (osteoblasts and osteoclasts), bone matrix (mRNA expression and IHC), and mineralization were investigated for a detailed characterization of osteoporosis. The study involved long-term observation up to 14 months (M14) after laparotomy or after OVX-Diet, with intermediate time points at M3 and M12. OVX-Diet rats showed enhanced osteoblastogenesis and osteoclastogenesis. Bone matrix markers (biglycan, COL1A1, tenascin C, and fibronectin) and low-density lipoprotein-5 (bone mass marker) were down-regulated at M12 in OVX-Diet rats. However, up-regulation of matrix markers and existence of unmineralized osteoid were seen at M3 and M14. Osteoclast markers (matrix metallopeptidase 9 and cathepsin K) were up-regulated at M14. Micro-computed tomography and biomechanics confirmed bone fragility of OVX-Diet rats, and quantitative RT-PCR revealed a higher turnover rate in the humerus than in lumbar vertebrae, suggesting enhanced bone formation and resorption in OVX-Diet rats. Such bone remodeling caused disturbed bone mineralization and severe bone loss, as reported in patients with high-turnover, postmenopausal osteoporosis. Therefore, this rat model may serve as a suitable tool to evaluate osteoporotic drugs and new biomaterials or fracture implants. Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

The effect of hierarchical micro/nanosurface titanium implant on osseointegration in ovariectomized sheep.

PubMed

Xiao, J; Zhou, H; Zhao, L; Sun, Y; Guan, S; Liu, B; Kong, L

2011-06-01

Hydrofluoric etching and anodized hierarchical micro/nanotextured surface titanium implant was placed in mandibles of ovariectomized sheep for 12 weeks, and it showed improved osseointegration by resonance frequency analysis (RFA), microcomputed tomography (micro-CT) evaluation, histomorphometry, and biomechanical test. This study aimed to investigate the effects of micro/nanotextured titanium implant on osseointegration in ovariectomized (OVX) sheep. The hierarchical micro/nanotextured surface of titanium implant was fabricated by acid in 0.5% (w/v) hydrofluoric (HF) and anodized in HF acid electrolytes with a DC power of 20 V, and the machined surface implants with no treatment served as control group. The implants were placed in mandibles of OVX sheep, respectively. Twelve weeks after implantation, RFA, microcomputed tomography, histomorphometry, and biomechanical tests were applied to detect the osseointegration of the two groups. The implant stability quotient (ISQ) values, the maximum pull-out forces, and the bone-implant contact (BIC) were 65.5 ± 6.3, 490.6 ± 72.7 N, and 58.31 ± 5.79% in the micro/nanogroup and 58.3 ± 8.9, 394.5 ± 54.5 N, and 46.85 ± 5.04% in the control group, respectively. There was no significant difference between the two groups in ISQ values (p > 0.05), but in the micro/nanogroup, the maximal pull-out force and the BIC were increased significantly (p < 0.05 or p < 0.01). Micro-CT analysis showed that the bone volume ratio and the trabecular number increased significantly (p < 0.01), and the trabecular separation decreased significantly (p < 0.05) in the micro/nanogroup. Implant modification by HF acid etching and anodization to form a hierarchical micro/nanotextured surface could improve titanium implant osseointegration in OVX sheep 12 weeks after implantation.

Coronary artery wall imaging in mice using osmium tetroxide and micro-computed tomography (micro-CT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pai, Vinay M.; Kozlowski, Megan; Donahue, Danielle

2012-05-10

The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary artery disease models, it is highly desirable to image coronary artery walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO{sub 4}) solution. As a tissue-staining contrast agent, OsO{sub 4} is retained in the vessel wall andmore » surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the artery wall visible in CT. Additionally, since OsO{sub 4} preferentially binds to lipids, it highlights lipid deposition in the artery wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE{sup -/-}) mice at 10 {mu}m resolution. The results show that walls of coronary arteries as small as 45 {mu}m in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO{sub 4} and micro-CT permits the visualization of the coronary artery wall in intact mouse hearts.« less

Micro-Computed Tomography Evaluation of ProTaper Next and BioRace Shaping Outcomes in Maxillary First Molar Curved Canals.

PubMed

Pasqualini, Damiano; Alovisi, Mario; Cemenasco, Andrea; Mancini, Lucia; Paolino, Davide Salvatore; Bianchi, Caterina Chiara; Roggia, Andrea; Scotti, Nicola; Berutti, Elio

2015-10-01

The aim of this micro-computed tomography study was to describe the shaping properties of ProGlider/ProTaper Next (PG/PTN) and ScoutRace/BioRace (SR/BR) nickel-titanium rotary systems. Thirty maxillary first permanent molars were selected. Mesiobuccal canals were randomly assigned (n = 15) to PG/PTN or SR/BR groups. Irrigation was performed with 5% NaOCl and 10% EDTA. Specimens were scanned (voxel size, 9.1 μm) for matching volumes and surface areas and post-treatment analyses. Root canal centering ability, canal geometry enlargement, and thickness of dentinal wall at inner curvature were assessed at apical level and point of maximum curvature. Results were analyzed with 4 one-way analyses of variance. Canal centering ability was superior in PG/PTN (P = .006 at apical level, P = .025 at point of maximum curvature). PG/PTN demonstrated a more conservative increase of canal areas (P = .027 at apical level, P = .038 at point of maximum curvature). Centrifugal increase in canal diameters did not significantly differ between groups (P = .65 at apical level, P = .61 at point of maximum curvature). Inner dentinal wall thickness was less reduced with PG/PTN compared with SR/BR, with no statistical differences (P = .23 at point of maximum curvature, P = .89 at apical level). PG/PTN shaping taper ranged between 6% and 7%. Neither system produced significant shaping errors in curved canals. PG/PTN system showed better preservation of canal anatomy. PTN offset section did not influence final preparation taper. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Micro-computed Tomography Provides High Accuracy Congenital Heart Disease Diagnosis in Neonatal and Fetal Mice

PubMed Central

Kim, Andrew J.; Francis, Richard; Liu, Xiaoqin; Devine, William A.; Ramirez, Ricardo; Anderton, Shane J.; Wong, Li Yin; Faruque, Fahim; Gabriel, George C.; Leatherbury, Linda; Tobita, Kimimasa; Lo, Cecilia W.

2013-01-01

Background Mice are well suited for modeling human congenital heart defects (CHD), given their four-chamber cardiac anatomy. However, mice with CHD invariably die prenatally/neonatally, causing CHD phenotypes to be missed. Therefore, we investigated the efficacy of noninvasive micro-computed tomography (micro-CT) to screen for CHD in stillborn/fetal mice. These studies were carried out using chemically mutagenized mice expected to be enriched for birth defects including CHD. Methods and Results Stillborn/fetal mice obtained from the breeding of N-ethyl-N-nitrosourea (ENU) mutagenized mice were formalin-fixed and stained with iodine, then micro-CT scanned. Those diagnosed with CHD and some CHD-negative pups were necropsied. A subset of these were further analyzed by histopathology to confirm the CHD/no-CHD diagnosis. Micro-CT scanning of 2105 fetal/newborn mice revealed an abundance of ventricular septal defects (VSD) (n=307). Overall, we observed an accuracy of 89.8% for VSD diagnosis. Outflow tract anomalies identified by micro-CT included double outlet right ventricle (n=36), transposition of the great arteries (n=14), and persistent truncus arteriosus (n=3). These were diagnosed with a 97.4% accuracy. Aortic arch anomalies also were readily detected with an overall 99.6% accuracy. This included right aortic arch (n=28) and coarctation/interrupted aortic arch (n=12). Also detected by micro-CT were atrioventricular septal defects (n=22), tricuspid hypoplasia/atresia (n=13), and coronary artery fistulas (n=16). They yielded accuracies of 98.9%, 100%, and 97.8% respectively. Conclusions Contrast enhanced micro-CT imaging in neonatal/fetal mice can reliably detect a wide spectrum of CHD. We conclude micro-CT imaging can be used for routine rapid assessments of structural heart defects in fetal/newborn mice. PMID:23759365

Enhancement of rotator cuff tendon-bone healing with fibroblast growth factor 2 impregnated in gelatin hydrogel sheets in a rabbit model.

PubMed

Tokunaga, Takuya; Karasugi, Tatsuki; Arimura, Hitoshi; Yonemitsu, Ryuji; Sakamoto, Hidetoshi; Ide, Junji; Mizuta, Hiroshi

2017-10-01

Application of fibroblast growth factor 2 (FGF-2) may improve the healing response after rotator cuff (RC) surgical repair. This study aimed to determine whether FGF-2-impregnated gelatin hydrogel sheet (GHS) incorporation into the bony trough on the greater tuberosity facilitates healing after RC surgical repair in rabbits. We assigned 120 adult male Japanese white rabbits treated with unilateral surgery for supraspinatus tendon repair into the following groups: suture-only group (suture); suture and GHS with phosphate-buffered saline (carrier); suture and GHS with 3 µg of FGF-2 (F3); and suture and GHS with 30 µg of FGF-2 (F30). The effect of FGF-2 was assessed using histologic, biomechanical, and microcomputed tomography evaluations at 2, 6, and 12 weeks. At 12 weeks, loose fibrovascular tissues emerged at the repair site in the suture and carrier groups and dense tendon-like tissues in the F3 and F30 groups, which demonstrated significantly higher ultimate load-to-failure and stress-to-failure at 12 weeks than that in the suture and carrier groups. Microcomputed tomography imaging showed ectopic calcification formation in some specimens from each group. Appearances or frequencies were similar among groups. The histologic and biomechanical effects of FGF-2 on RC healing were obvious at ≥6 weeks postoperatively. FGF-2-impregnated GHS incorporation into the bony trough on the greater tuberosity before RC surgical repair is feasible and results in histologic and biomechanical improvements during RC healing in rabbits. No detrimental effect on ectopic calcification was observed. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Bone regeneration by means of a three-dimensional printed scaffold in a rat cranial defect.

PubMed

Kwon, Doo Yeon; Park, Ji Hoon; Jang, So Hee; Park, Joon Yeong; Jang, Ju Woong; Min, Byoung Hyun; Kim, Wan-Doo; Lee, Hai Bang; Lee, Junhee; Kim, Moon Suk

2018-02-01

Recently, computer-designed three-dimensional (3D) printing techniques have emerged as an active research area with almost unlimited possibilities. In this study, we used a computer-designed 3D scaffold to drive new bone formation in a bone defect. Poly-L-lactide (PLLA) and bioactive β-tricalcium phosphate (TCP) were simply mixed to prepare ink. PLLA + TCP showed good printability from the micronozzle and solidification within few seconds, indicating that it was indeed printable ink for layer-by-layer printing. In the images, TCP on the surface of (and/or inside) PLLA in the printed PLLA + TCP scaffold looked dispersed. MG-63 cells (human osteoblastoma) adhered to and proliferated well on the printed PLLA + TCP scaffold. To assess new bone formation in vivo, the printed PLLA + TCP scaffold was implanted into a full-thickness cranial bone defect in rats. The new bone formation was monitored by microcomputed tomography and histological analysis of the in vivo PLLA + TCP scaffold with or without MG-63 cells. The bone defect was gradually spontaneously replaced with new bone tissues when we used both bioactive TCP and MG-63 cells in the PLLA scaffold. Bone formation driven by the PLLA + TCP30 scaffold with MG-63 cells was significantly greater than that in other experimental groups. Furthermore, the PLLA + TCP scaffold gradually degraded and matched well the extent of the gradual new bone formation on microcomputed tomography. In conclusion, the printed PLLA + TCP scaffold effectively supports new bone formation in a cranial bone defect. Copyright © 2017 John Wiley & Sons, Ltd.

Micro-Computed Tomography Analysis of the Root Canal Morphology of Palatal Roots of Maxillary First Molars.

PubMed

Marceliano-Alves, Marília; Alves, Flávio Rodrigues Ferreira; Mendes, Daniel de Melo; Provenzano, José Claudio

2016-02-01

A thorough knowledge of root canal anatomy is critical for successful root canal treatments. This study evaluated the internal anatomy of the palatal roots of maxillary first molars with micro-computed tomography (microCT). The palatal roots of extracted maxillary first molars (n = 169) were scanned with microCT to determine several anatomic parameters, including main canal classification, lateral canal occurrence and location, degree of curvature, main foramen position, apical constriction presence, diameters 1 and 2 mm from the apex and 1 mm from the foramen, minor dentin thickness in those regions, canal volume, surface area, and convexity. All canals were classified as Vertucci type I. The cross sections were oval in 61% of the canals. Lateral canals were found in 25% of the samples. The main foramen did not coincide with the root apex in 95% of the cases. Only 8% of the canals were classified as straight. Apical constriction was identified in 38% of the roots. The minor and major canal diameters and minor dentin thickness were decreased near the apex. The minor dentin thickness 1 mm from the foramen was 0.82 mm. The palatal canals exhibited a volume of 6.91 mm(3) and surface area of 55.31 mm(2) and were rod-shaped. The root canals of the palatal roots were classified as type I. However, some factors need to be considered during the treatment of these roots, including the frequent ocurrence of moderate/severe curvatures, oval-shaped cross-sections, and lateral canals, noncoincidence of the apical foramen with the root apex, and absence of apical constriction in most cases. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Micro-computed tomography: Applications for high-resolution skeletal density determinations: An example using annually banded crustose coralline algae

NASA Astrophysics Data System (ADS)

Chan, P.; Halfar, J.; Norley, C. J. D.; Pollmann, S. I.; Adey, W.; Holdsworth, D. W.

2017-09-01

Warming and acidification of the world's oceans are expected to have widespread consequences for marine biodiversity and ecosystem functioning. However, due to the relatively short record of instrumental observations, one has to rely upon geochemical and physical proxy information stored in biomineralized shells and skeletons of calcareous marine organisms as in situ recorders of past environments. Of particular interest is the response of marine calcifiers to ocean acidification through the examination of structural growth characteristics. Here we demonstrate the application of micro-computed tomography (micro-CT) for three-dimensional visualization and analysis of growth, skeletal density, and calcification in a slow-growing, annually banded crustose coralline alga Clathromorphum nereostratum (increment width ˜380 µm). X-ray images and time series of skeletal density were generated at 20 µm resolution and rebinned to 40, 60, 80, and 100 µm for comparison in a sensitivity analysis. Calcification rates were subsequently calculated as the product of density and growth (linear extension). While both skeletal density and calcification rates do not significantly differ at varying spatial resolutions (the latter being strongly influenced by growth rates), clear visualization of micron-scale growth features and the quantification of structural changes on subannual time scales requires higher scanning resolutions. In the present study, imaging at 20 µm resolution reveals seasonal cycles in density that correspond to summer/winter variations in skeletal structure observed using scanning electron microscopy (SEM). Micro-CT is a fast, nondestructive, and high-resolution technique for structural and morphometric analyses of temporally banded paleoclimate archives, particularly those that exhibit slow or compressed growth or micron-scale structures.

Micro-computed tomography assessment of human alveolar bone: bone density and three-dimensional micro-architecture.

PubMed

Kim, Yoon Jeong; Henkin, Jeffrey

2015-04-01

Micro-computed tomography (micro-CT) is a valuable means to evaluate and secure information related to bone density and quality in human necropsy samples and small live animals. The aim of this study was to assess the bone density of the alveolar jaw bones in human cadaver, using micro-CT. The correlation between bone density and three-dimensional micro architecture of trabecular bone was evaluated. Thirty-four human cadaver jaw bone specimens were harvested. Each specimen was scanned with micro-CT at resolution of 10.5 μm. The bone volume fraction (BV/TV) and the bone mineral density (BMD) value within a volume of interest were measured. The three-dimensional micro architecture of trabecular bone was assessed. All the parameters in the maxilla and the mandible were subject to comparison. The variables for the bone density and the three-dimensional micro architecture were analyzed for nonparametric correlation using Spearman's rho at the significance level of p < .05. A wide range of bone density was observed. There was a significant difference between the maxilla and mandible. All micro architecture parameters were consistently higher in the mandible, up to 3.3 times greater than those in the maxilla. The most linear correlation was observed between BV/TV and BMD, with Spearman's rho = 0.99 (p = .01). Both BV/TV and BMD were highly correlated with all micro architecture parameters with Spearman's rho above 0.74 (p = .01). Two aspects of bone density using micro-CT, the BV/TV and BMD, are highly correlated with three-dimensional micro architecture parameters, which represent the quality of trabecular bone. This noninvasive method may adequately enhance evaluation of the alveolar bone. © 2013 Wiley Periodicals, Inc.

Contrast Agents for Micro-Computed Tomography of Microdamage in Bone

DTIC Science & Technology

2008-01-01

4 × 50–60 mm, were sectioned from the cortex at the mid-diaphysis of a single bovine tibia. Two symmetric notches were machined on the periosteal ...endosteal surface, 0.6 mm from the periosteal surface and 0.2 mm from the beam sides (Fig. 2). Gaussian smoothing was applied to suppress noise and 3D...microdamage in trabecular bone with barium sulfate (BaSO4); (2) apply the technique to detect microdamage induced in bovine tibial trabecular bone specimens

The Role of Peripheral Nerve Function in Age-Related Bone Loss and Changes in Bone Adaptation

DTIC Science & Technology

2013-10-01

mechanical loading (months 6-18): 2a. Strain gage analysis of bone strain during tibial compression (months 6-7) 2b. Capsaicin or vehicle treatment...of neonatal mice (months 6-8) 2c. Tibial compression of capsaicin- and vehicle-injected mice (months 8-10) 2d. Micro-computed tomography of mouse...the endosteal and periosteal surfaces. Capsaicin treatment altered bone formation rate parameters in the tibias of treated mice (Table 2). There

Flow velocity-driven differentiation of human mesenchymal stromal cells in silk fibroin scaffolds: A combined experimental and computational approach.

PubMed

Vetsch, Jolanda Rita; Betts, Duncan Colin; Müller, Ralph; Hofmann, Sandra

2017-01-01

Mechanical loading plays a major role in bone remodeling and fracture healing. Mimicking the concept of mechanical loading of bone has been widely studied in bone tissue engineering by perfusion cultures. Nevertheless, there is still debate regarding the in-vitro mechanical stimulation regime. This study aims at investigating the effect of two different flow rates (vlow = 0.001m/s and vhigh = 0.061m/s) on the growth of mineralized tissue produced by human mesenchymal stromal cells cultured on 3-D silk fibroin scaffolds. The flow rates applied were chosen to mimic the mechanical environment during early fracture healing or during bone remodeling, respectively. Scaffolds cultured under static conditions served as a control. Time-lapsed micro-computed tomography showed that mineralized extracellular matrix formation was completely inhibited at vlow compared to vhigh and the static group. Biochemical assays and histology confirmed these results and showed enhanced osteogenic differentiation at vhigh whereas the amount of DNA was increased at vlow. The biological response at vlow might correspond to the early stage of fracture healing, where cell proliferation and matrix production is prominent. Visual mapping of shear stresses, simulated by computational fluid dynamics, to 3-D micro-computed tomography data revealed that shear stresses up to 0.39mPa induced a higher DNA amount and shear stresses between 0.55mPa and 24mPa induced osteogenic differentiation. This study demonstrates the feasibility to drive cell behavior of human mesenchymal stromal cells by the flow velocity applied in agreement with mechanical loading mimicking early fracture healing (vlow) or bone remodeling (vhigh). These results can be used in the future to tightly control the behavior of human mesenchymal stromal cells towards proliferation or differentiation. Additionally, the combination of experiment and simulation presented is a strong tool to link biological responses to mechanical stimulation and can be applied to various in-vitro cultures to improve the understanding of the cause-effect relationship of mechanical loading.

Variability of morphometric parameters of human trabecular tissue from coxo-arthritis and osteoporotic samples.

PubMed

Marinozzi, Franco; Marinozzi, Andrea; Bini, Fabiano; Zuppante, Francesca; Pecci, Raffaella; Bedini, Rossella

2012-01-01

Morphometric and architectural bone parameters change in diseases such as osteoarthritis and osteoporosis. The mechanical strength of bone is primarily influenced by bone quantity and quality. Bone quality is defined by parameters such as trabecular thickness, trabecular separation, trabecular density and degree of anisotropy that describe the micro-architectural structure of bone. Recently, many studies have validated microtomography as a valuable investigative technique to assess bone morphometry, thanks to micro-CT non-destructive, non-invasive and reliability features, in comparison to traditional techniques such as histology. The aim of this study is the analysis by micro-computed tomography of six specimens, extracted from patients affected by osteoarthritis and osteoporosis, in order to observe the tridimensional structure and calculate several morphometric parameters.

Micro-computed tomographic analysis of progression of artificial enamel lesions in primary and permanent teeth after resin infiltration.

PubMed

Ozgul, Betul Memis; Orhan, Kaan; Oz, Firdevs Tulga

2015-09-01

We investigated inhibition of lesion progression in artificial enamel lesions. Lesions were created on primary and permanent anterior teeth (n = 10 each) and were divided randomly into two groups with two windows: Group 1 (window A: resin infiltration; window B: negative control) and Group 2 (window A: resin infiltration + fluoride varnish; window B: fluoride varnish). After pH cycling, micro-computed tomography was used to analyze progression of lesion depth and changes in mineral density. Resin infiltration and resin infiltration + fluoride varnish significantly inhibited progression of lesion depth in primary teeth (P < 0.05). Inhibition of lesion depth progression in permanent teeth was significantly greater after treatment with resin infiltration + fluoride varnish than in the negative control (P < 0.05). Change in mineral density was smaller in the resin infiltration and resin infiltration + fluoride varnish groups; however, the difference was not significant for either group (P > 0.05). Resin infiltration is a promising method of inhibiting progression of caries lesions.

Differences in the developmental origins of the periosteum may influence bone healing.

PubMed

Ichikawa, Y; Watahiki, J; Nampo, T; Nose, K; Yamamoto, G; Irie, T; Mishima, K; Maki, K

2015-08-01

The jaw bone, unlike most other bones, is derived from neural crest stem cells, so we hypothesized that it may have different characteristics to bones from other parts of the body, especially in the nature of its periosteum. The periosteum exhibits osteogenic potential and has received considerable attention as a grafting material for the repair of bone and joint defects. Gene expression profiles of jaw bone and periosteum were evaluated by DNA microarray and real-time polymerase chain reaction. Furthermore, we perforated an area 2 mm in diameter on mouse frontal and parietal bones. Bone regeneration of these calvarial defects was evaluated using microcomputed tomography and histological analysis. The DNA microarray data revealed close homology between the gene expression profiles within the ilium and femur. The gene expression of Wnt-1, SOX10, nestin, and musashi-1 were significantly higher in the jaw bone than in other locations. Microcomputed tomography and histological analysis revealed that the jaw bone had superior bone regenerative abilities than other bones. Jaw bone periosteum exhibits a unique gene expression profile that is associated with neural crest cells and has a positive influence on bone regeneration when used as a graft material to repair bone defects. A full investigation of the biological and mechanical properties of jaw bone as an alternative graft material for jaw reconstructive surgery is recommended. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The local administration of parathyroid hormone encourages the healing of bone defects in the rat calvaria: Micro-computed tomography, histological and histomorphometric evaluation.

PubMed

Auersvald, Caroline Moreira; Santos, Felipe Rychuv; Nakano, Mayara Mytie; Leoni, Graziela Bianchi; de Sousa Neto, Manoel Damião; Scariot, Rafaela; Giovanini, Allan Fernando; Deliberador, Tatiana Miranda

2017-07-01

To evaluate the effect of a single-dose local administration of PTH on bone healing in rat calvarial bone defects by means of micro-computed tomography, histological and histomorphometric analysis. Critical-size cranial osteotomy defects were created in 42 male rats. The animals were randomly divided into 3 groups. In the C Group, the bone defect was only filled with a blood clot. In the S Group, it was filled with a collagen sponge and covered with bovine cortical membrane. In the PTH Group, the defect was filled with a collagen sponge soaked with PTH and covered with bovine cortical membrane. The groups were further split in two for euthanasia 15 and 60days post-surgery. Data was statistically analyzed with t-tests for independent samples or the nonparametric Mann-Whitney test when applicable. Intragroup comparisons were analyzed with paired t-tests (p<0.05). Micro-CT analysis results did not demonstrate statistically significant intergroup differences. At 15days post-surgery, the histomorphometric analysis showed that the PTH Group exhibited a significantly higher percentage of bone formation compared with the S Group. At 60days post-surgery, a higher percentage of new bone was observed in the PTH group. The results suggest that the local administration of PTH encouraged the bone healing in critical-size calvarial defects in rats. Copyright © 2017 Elsevier Ltd. All rights reserved.

Micro-computed tomography in murine models of cerebral cavernous malformations as a paradigm for brain disease.

PubMed

Girard, Romuald; Zeineddine, Hussein A; Orsbon, Courtney; Tan, Huan; Moore, Thomas; Hobson, Nick; Shenkar, Robert; Lightle, Rhonda; Shi, Changbin; Fam, Maged D; Cao, Ying; Shen, Le; Neander, April I; Rorrer, Autumn; Gallione, Carol; Tang, Alan T; Kahn, Mark L; Marchuk, Douglas A; Luo, Zhe-Xi; Awad, Issam A

2016-09-15

Cerebral cavernous malformations (CCMs) are hemorrhagic brain lesions, where murine models allow major mechanistic discoveries, ushering genetic manipulations and preclinical assessment of therapies. Histology for lesion counting and morphometry is essential yet tedious and time consuming. We herein describe the application and validations of X-ray micro-computed tomography (micro-CT), a non-destructive technique allowing three-dimensional CCM lesion count and volumetric measurements, in transgenic murine brains. We hereby describe a new contrast soaking technique not previously applied to murine models of CCM disease. Volumetric segmentation and image processing paradigm allowed for histologic correlations and quantitative validations not previously reported with the micro-CT technique in brain vascular disease. Twenty-two hyper-dense areas on micro-CT images, identified as CCM lesions, were matched by histology. The inter-rater reliability analysis showed strong consistency in the CCM lesion identification and staging (K=0.89, p<0.0001) between the two techniques. Micro-CT revealed a 29% greater CCM lesion detection efficiency, and 80% improved time efficiency. Serial integrated lesional area by histology showed a strong positive correlation with micro-CT estimated volume (r(2)=0.84, p<0.0001). Micro-CT allows high throughput assessment of lesion count and volume in pre-clinical murine models of CCM. This approach complements histology with improved accuracy and efficiency, and can be applied for lesion burden assessment in other brain diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

In vivo microcomputed tomography evaluation of rat alveolar bone and root resorption during orthodontic tooth movement.

PubMed

Ru, Nan; Liu, Sean Shih-Yao; Zhuang, Li; Li, Song; Bai, Yuxing

2013-05-01

To observe the real-time microarchitecture changes of the alveolar bone and root resorption during orthodontic treatment. A 10 g force was delivered to move the maxillary left first molars mesially in twenty 10-week-old rats for 14 days. The first molar and adjacent alveolar bone were scanned using in vivo microcomputed tomography at the following time points: days 0, 3, 7, and 14. Microarchitecture parameters, including bone volume fraction, structure model index, trabecular thickness, trabecular number, and trabecular separation of alveolar bone, were measured on the compression and tension side. The total root volume was measured, and the resorption crater volume at each time point was calculated. Univariate repeated measures analysis of variance with Bonferroni corrections were performed to compare the differences in each parameter between time points with significance level at P < .05. From day 3 to day 7, bone volume fraction, structure model index, trabecular thickness, and trabecular separation decreased significantly on the compression side, but the same parameters increased significantly on the tension side from day 7 to day 14. Root resorption volume of the mesial root increased significantly on day 7 of orthodontic loading. Real-time root and bone resorption during orthodontic movement can be observed in 3 dimensions using in vivo micro-CT. Alveolar bone resorption and root resorption were observed mostly in the apical third on day 7 on the compression side; bone formation was observed on day 14 on the tension side during orthodontic tooth movement.

Micro-computed Tomography versus the Cross-sectioning Method to Evaluate Dentin Defects Induced by Different Mechanized Instrumentation Techniques.

PubMed

Stringheta, Carolina Pessoa; Pelegrine, Rina Andréa; Kato, Augusto Shoji; Freire, Laila Gonzales; Iglecias, Elaine Faga; Gavini, Giulio; Bueno, Carlos Eduardo da Silveira

2017-12-01

The objective of this study was to compare the methods of micro-computed tomography (micro-CT) and cross-sectioning followed by stereomicroscopy in assessing dentinal defects after instrumentation with different mechanized systems. Forty mesial roots of mandibular molars were scanned and divided into 4 groups (n = 10): Group R, Reciproc; Group PTN, ProTaper Next; Group WOG, WaveOne Gold; Group PDL, ProDesign Logic. After instrumentation, the roots were once again submitted to a micro-CT scan, and then sectioned at 3, 6, and 9 mm from the apex, and assessed for the presence of complete and incomplete dentinal defects under a stereomicroscope. The nonparametric Kruskal-Wallis, Friedman, and Wilcoxon tests were used in the statistical analysis. The study used a significance level of 5%. The total number of defects observed by cross-sectioning followed by stereomicroscopy was significantly higher than that observed by micro-CT, in all of the experimental groups (P ≤ .05). All of the defects identified in the postoperative period were already present in the corresponding preoperative period. There was no significant difference among the instrumentation systems as to the median numbers of defects, for either cross-sectioning followed by stereomicroscopy or micro-CT, at all the root levels (P > .05). In the micro-CT analysis, no significant difference was found between the median numbers of pre- and postinstrumentation defects, regardless of the instrumentation system (P > .05). None of the evaluated instrumentation systems led to the formation of new dentin defects. All of the defects identified in the stereomicroscopic analysis were already present before instrumentation, or were absent at both time points in the micro-CT analysis, indicating that the formation of new defects resulted from the sectioning procedure performed before stereomicroscopy and not from instrumentation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Efficacy of Needle, Ultrasonic, and Endoactivator Irrigation and Photon-Induced Photoacoustic Streaming in Removing Calcium Hydroxide from the Main Canal and Isthmus: An In Vitro Micro-Computed Tomography and Scanning Electron Microscopy Study.

PubMed

Li, Dongxia; Jiang, Shan; Yin, Xingzhe; Chang, Jeffrey Wen Wei; Ke, Jie; Zhang, Chengfei

2015-06-01

The aim of this in vitro study was to use high-resolution micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) to compare the efficacy of four irrigation techniques [needle, ultrasonic, EndoActivator, and photon-induced photoacoustic streaming (PIPS)] in removing calcium hydroxide (Ca[OH]2) from the root canal and isthmus of maxillary premolars. Twenty-four maxillary first premolars were selected based on the presence of isthmus regions on micro-CT scans. Root canals were instrumented with an F2 file using ProTaper rotary instruments and filled with Ca(OH)2 paste. Samples were stored at 37°C and 100% humidity for 1 week and randomly divided into four groups (n=6 each), according to irrigation technique. Samples were scanned with micro-CT before instrumentation, after Ca(OH)2 filling, and after irrigation. Ca(OH)2 reduction in the coronal, middle, and apical thirds and in the isthmus were assessed with three-dimensional image analysis. Next, specimens were split longitudinally, and canal walls were examined with SEM for Ca(OH)2 residues. Data were statistically evaluated with the Kruskal-Wallis and Mann-Whitney tests (p=0.05). The PIPS and ultrasonic groups showed greater Ca(OH)2 reduction in the apical third and higher cleanliness of the isthmus than the EndoActivator and needle irrigation groups (p<0.05). Ca(OH)2 residue scores in the PIPS and ultrasonic groups were significantly lower than those in the EndoActivator and needle groups in all regions of the root canals (p<0.05). There was no significant difference between PIPS and ultrasonic groups (p>0.05), or between EndoActivator and needle groups (p>0.05). PIPS and ultrasonic irrigation more effectively removed Ca(OH)2 from the main canal and isthmus in maxillary premolars than did EndoActivator or needle irrigation.

A new device for improving dental implants anchorage: a histological and micro-computed tomography study in the rabbit.

PubMed

Barak, Shlomo; Neuman, Moshe; Iezzi, Giovanna; Piattelli, Adriano; Perrotti, Vittoria; Gabet, Yankel

2016-08-01

In the present study, a new healing cap that could generate a pulsed electromagnetic field (PEMF) around titanium implants to stimulate peri-implant osteogenesis was tested in the rabbit model. A total of 22 implants were inserted in the proximal tibial metaphysis of 22 rabbits. A healing cap containing the active device was inserted in half of the implants (11 test implants); an "empty" healing cap was inserted in the other ones (11 control implants). The animals were euthanized after 2 and 4 weeks, and the samples were processed for micro-computed tomography and histology. The peri-implant volume was divided into coronal (where the PEMF was the strongest) and apical regions. Most of the effects of the tested device were confined to the coronal region. Two weeks post-implantation, test implants showed a significant 56% higher trabecular bone fraction (BV/TV), associated with enhanced trabecular number (Tb.N, +37%) and connectivity density (Conn.D, +73%) as compared to the control group; at 4 weeks, the PEMF induced a 69% increase in BV/TV and 34% increase of Tb.N. There was no difference in the trabecular thickness (Tb.Th) at either time point. Furthermore, we observed a 48% higher bone-to-implant contact (BIC) in the test implants vs. controls after 2 weeks; this increase tended to remain stable until the fourth week. Mature trabecular and woven bone were observed in direct contact with the implant surface with no gaps or connective tissue at the bone-implant interface. These results indicate that the PEMF device stimulated early bone formation around dental implants resulting in higher peri-implant BIC and bone mass already after 2 weeks which suggests an acceleration of the osseointegration process by more than three times. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of marginal and internal adaptation of hybrid and nanoceramic systems with microcomputed tomography: An in vitro study.

PubMed

Yildirim, Güler; Uzun, Ismail H; Keles, Ali

2017-08-01

The accuracy of recently introduced chairside computer-aided design and computer-aided manufacturing (CAD-CAM) blocks is not well established, and marginal integrity and internal adaptation are not known. The purpose of this in vitro study was to evaluate the marginal and internal adaptation of hybrid and nanoceramics using microcomputed tomography (μ-CT). The marginal and internal adaptation of 3 polymer-infiltrated ceramic-network (PICN) materials (Vita Enamic [VE]; Lava Ultimate [LU]; Vita Suprinity [VS]) were compared with lithium disilicate (IPS e.max.CAD, IPS). Ninety-six specimens (48 dies and 48 crowns) were prepared (n=12 each group) using a chairside CAD-CAM system. The restorations were scanned with μ-CT, with 160 measurements made for each crown, and used in 2-dimensional (2D) analysis. The marginal adaptation of marginal discrepancy (MD), absolute marginal discrepancy (AMD), internal adaptation of shoulder area (SA), axial space (AS), and occlusal space (OS) were compared using appropriate statistical analysis methods (α=.05). Cement volumes were compared using 3D analysis. The IPS blocks showed higher MD (130 μm), AMD (156 μm), SA (111 μm) (P<.05), AS (52 μm), and OS (192 μm) than the other blocks (P<.01). The adaptation values of VS were significantly lower than those of the IPS block (P<.05). The adaption values of the LU and VE blocks were significantly lower than those of others (P<.01) but were statistically similar to one another (P>.05). IPS had the largest cement space at 18 mm 3 (P<.01). The marginal and internal adaptation values were within a clinically acceptable range for all 3 hybrids and nanoceramics tested. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Quantifying floral shape variation in 3D using microcomputed tomography: a case study of a hybrid line between actinomorphic and zygomorphic flowers.

PubMed

Wang, Chun-Neng; Hsu, Hao-Chun; Wang, Cheng-Chun; Lee, Tzu-Kuei; Kuo, Yan-Fu

2015-01-01

The quantification of floral shape variations is difficult because flower structures are both diverse and complex. Traditionally, floral shape variations are quantified using the qualitative and linear measurements of two-dimensional (2D) images. The 2D images cannot adequately describe flower structures, and thus lead to unsatisfactory discrimination of the flower shape. This study aimed to acquire three-dimensional (3D) images by using microcomputed tomography (μCT) and to examine the floral shape variations by using geometric morphometrics (GM). To demonstrate the advantages of the 3D-μCT-GM approach, we applied the approach to a second-generation population of florist's gloxinia (Sinningia speciosa) crossed from parents of zygomorphic and actinomorphic flowers. The flowers in the population considerably vary in size and shape, thereby served as good materials to test the applicability of the proposed phenotyping approach. Procedures were developed to acquire 3D volumetric flower images using a μCT scanner, to segment the flower regions from the background, and to select homologous characteristic points (i.e., landmarks) from the flower images for the subsequent GM analysis. The procedures identified 95 landmarks for each flower and thus improved the capability of describing and illustrating the flower shapes, compared with typically lower number of landmarks in 2D analyses. The GM analysis demonstrated that flower opening and dorsoventral symmetry were the principal shape variations of the flowers. The degrees of flower opening and corolla asymmetry were then subsequently quantified directly from the 3D flower images. The 3D-μCT-GM approach revealed shape variations that could not be identified using typical 2D approaches and accurately quantified the flower traits that presented a challenge in 2D images. The approach opens new avenues to investigate floral shape variations.

Imaging the Human Aqueous Humor Outflow Pathway in Human Eyes by Three Dimensional Micro-Computed Tomography (3D micro-CT)

PubMed Central

Hann, Cheryl R.; Bentley, Michael D.; Vercnocke, Andrew; Ritman, Erik L.; Fautsch, Michael P.

2011-01-01

The site of outflow resistance leading to elevated intraocular pressure in primary open angle glaucoma is believed to be located in the region of Schlemm’s canal inner wall endothelium, its basement membrane and the adjacent juxtacanalicular tissue. Evidence also suggests collector channels and intrascleral vessels may have a role in intraocular pressure in both normal and glaucoma eyes. Traditional imaging modalities limit the ability to view both proximal and distal portions of the trabecular outflow pathway as a single unit. In this study, we examined the effectiveness of three-dimensional micro-computed tomography (3D micro-CT) as a potential method to view the trabecular outflow pathway. Two normal human eyes were used: one immersion fixed in 4% paraformaldehyde, and one with anterior chamber perfusion at 10 mmHg followed by perfusion fixation in 4% paraformaldehyde/2% glutaraldehyde. Both eyes were postfixed in 1% osmium tetroxide, and scanned with 3D micro-CT at 2 µm or 5 µm voxel resolution. In the immersion fixed eye, 24 collector channels were identified with an average orifice size of 27.5 ± 5 µm. In comparison, the perfusion fixed eye had 29 collector channels with a mean orifice size of 40.5 ± 13 µm. Collector channels were not evenly dispersed around the circumference of the eye. There was no significant difference in the length of Schlemm’s canal in the immersed versus the perfused eye (33.2 versus 35.1 mm). Structures, locations and size measurements identified by 3D micro-CT were confirmed by correlative light microscopy. These findings confirm 3D micro-CT can be used effectively for the non-invasive examination of the trabecular meshwork, Schlemm’s canal, collector channels and intrascleral vasculature that comprise the distal outflow pathway. This imaging modality will be useful for noninvasive study of the role of the trabecular outflow pathway as a whole unit. PMID:21187085

Promising efficacy of Escherichia coli recombinant human bone morphogenetic protein-2 in collagen sponge for ectopic and orthotopic bone formation and comparison with mammalian cell recombinant human bone morphogenetic protein-2.

PubMed

Kim, In Sook; Lee, Eui Nam; Cho, Tae Hyung; Song, Yun Mi; Hwang, Soon Jung; Oh, Ji Hye; Park, Eun Kyung; Koo, Tai Young; Seo, Young-Kwon

2011-02-01

Nonglycosylated recombinant human bone morphogenetic protein (rhBMP)-2 prepared in Escherichia coli (E. coli rhBMP-2) has recently been considered as an alternative to mammalian cell rhBMP-2. However, its clinical use is still limited owing to lack of evidence for osteogenic activity comparable with that of mammalian cell rhBMP-2 via microcomputed tomography-based analysis. Therefore, this study aimed to evaluate the ability of E. coli rhBMP-2 in absorbable collagen sponge to form ectopic and orthotopic bone and to compare it to that of mammalian rhBMP-2. In vitro investigation was performed to study osteoblast differentiation of human mesenchymal stromal cells. Both types of rhBMP-2 enhanced proliferation, alkaline phosphatase activity, and matrix mineralization of human mesenchymal stromal cells at similar levels. Similar tendencies were observed in microcomputed tomography analysis, which determined bone volume, fractional bone volume, trabecular thickness, trabecular separation, bone mineral density, and other characteristics. Histology from an in vivo osteoinductivity test and from a rat calvarial defect model demonstrated a dose-dependent increase in local bone formation. The E. coli rhBMP-2 group (5 μg) not only induced complete regeneration of an 8-mm critical-sized defect at 4 weeks, but also led to new bone with the same bone mineral density as normal bone at 8 weeks, with the same efficiency as that of mammalian cell rhBMP-2 (5 μg). These uniformly favorable results provide evidence that the osteogenic activity of E. coli rhBMP-2 is not inferior to that of mammalian cell rhBMP-2 despite its low solubility and lack of gylcosylation. These results suggest that the application of E. coli rhBMP-2 in absorbable collagen sponge may be a promising equivalent to mammalian cell rhBMP-2 in bone tissue engineering.

Imaging the Aqueous Humor Outflow Pathway in Human Eyes by Three-dimensional Micro-computed Tomography (3D micro-CT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

C Hann; M Bentley; A Vercnocke

2011-12-31

The site of outflow resistance leading to elevated intraocular pressure in primary open-angle glaucoma is believed to be located in the region of Schlemm's canal inner wall endothelium, its basement membrane and the adjacent juxtacanalicular tissue. Evidence also suggests collector channels and intrascleral vessels may have a role in intraocular pressure in both normal and glaucoma eyes. Traditional imaging modalities limit the ability to view both proximal and distal portions of the trabecular outflow pathway as a single unit. In this study, we examined the effectiveness of three-dimensional micro-computed tomography (3D micro-CT) as a potential method to view the trabecularmore » outflow pathway. Two normal human eyes were used: one immersion fixed in 4% paraformaldehyde and one with anterior chamber perfusion at 10 mmHg followed by perfusion fixation in 4% paraformaldehyde/2% glutaraldehyde. Both eyes were postfixed in 1% osmium tetroxide and scanned with 3D micro-CT at 2 {mu}m or 5 {mu}m voxel resolution. In the immersion fixed eye, 24 collector channels were identified with an average orifice size of 27.5 {+-} 5 {mu}m. In comparison, the perfusion fixed eye had 29 collector channels with a mean orifice size of 40.5 {+-} 13 {mu}m. Collector channels were not evenly dispersed around the circumference of the eye. There was no significant difference in the length of Schlemm's canal in the immersed versus the perfused eye (33.2 versus 35.1 mm). Structures, locations and size measurements identified by 3D micro-CT were confirmed by correlative light microscopy. These findings confirm 3D micro-CT can be used effectively for the non-invasive examination of the trabecular meshwork, Schlemm's canal, collector channels and intrascleral vasculature that comprise the distal outflow pathway. This imaging modality will be useful for non-invasive study of the role of the trabecular outflow pathway as a whole unit.« less

Development of computational small animal models and their applications in preclinical imaging and therapy research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Tianwu; Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch; Geneva Neuroscience Center, Geneva University, Geneva CH-1205

The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and themore » development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.« less

Assessment of BoneTtissue Mineralization by Conventional X-ray Microcomputed tomography: Comparison with Synchrotron Radiation Microcomputed Tomography and Ash Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kazakia,G.; Burghardt, A.; Cheung, S.

2008-01-01

Assessment of bone tissue mineral density (TMD) may provide information critical to the understanding of mineralization processes and bone biomechanics. High-resolution three-dimensional assessment of TMD has recently been demonstrated using synchrotron radiation microcomputed tomography (SR{mu}CT); however, this imaging modality is relatively inaccessible due to the scarcity of SR facilities. Conventional desktop {mu}CT systems are widely available and have been used extensively to assess bone microarchitecture. However, the polychromatic source and cone-shaped beam geometry complicate assessment of TMD by conventional {mu}CT. The goal of this study was to evaluate {mu}CT-based measurement of degree and distribution of tissue mineralization in a quantitative,more » spatially resolved manner. Specifically, {mu}CT measures of bone mineral content (BMC) and TMD were compared to those obtained by SR{mu}CT and gravimetric methods. Cylinders of trabecular bone were machined from human femoral heads (n=5), vertebrae (n=5), and proximal tibiae (n=4). Cylinders were imaged in saline on a polychromatic {mu}CT system at an isotropic voxel size of 8 {mu}m. Volumes were reconstructed using beam hardening correction algorithms based on hydroxyapatite (HA)-resin wedge phantoms of 200 and 1200 mgHA/cm3. SR{mu}CT imaging was performed at an isotropic voxel size of 7.50 {mu}m at the National Synchrotron Light Source. Attenuation values were converted to HA concentration using a linear regression derived by imaging a calibration phantom. Architecture and mineralization parameters were calculated from the image data. Specimens were processed using gravimetric methods to determine ash mass and density. {mu}CT-based BMC values were not affected by altering the beam hardening correction. Volume-averaged TMD values calculated by the two corrections were significantly different (p=0.008) in high volume fraction specimens only, with the 1200 mgHA/cm3 correction resulting in a 4.7% higher TMD value. {mu}CT and SR{mu}CT provided significantly different measurements of both BMC and TMD (p<0.05). In high volume fraction specimens, {mu}CT with 1200 mgHA/cm3 correction resulted in BMC and TMD values 16.7% and 15.0% lower, respectively, than SR{mu}CT values. In low volume fraction specimens, {mu}CT with 1200 mgHA/cm3 correction resulted in BMC and TMD values 12.8% and 12.9% lower, respectively, than SR{mu}CT values. {mu}CT and SR{mu}CT values were well-correlated when volume fraction groups were considered individually (BMC R2=0.97-1.00; TMD R2=0.78-0.99). Ash mass and density were higher than the SR{mu}CT equivalents by 8.6% in high volume fraction specimens and 10.9% in low volume fraction specimens (p<0.05). BMC values calculated by tomography were highly correlated with ash mass (ash versus {mu}CT R2=0.96-1.00; ash versus SR{mu}CT R2=0.99-1.00). TMD values calculated by tomography were moderately correlated with ash density (ash versus {mu}CT R2=0.64-0.72; ash versus SR{mu}CT R2=0.64). Spatially resolved comparisons highlighted substantial geometric nonuniformity in the {mu}CT data, which were reduced (but not eliminated) using the 1200 mg HA/cm3 beam hardening correction, and did not exist in the SR{mu}CT data. This study represents the first quantitative comparison of {mu}CT mineralization evaluation against SR{mu}CT and gravimetry. Our results indicate that {mu}CT mineralization measures are underestimated but well-correlated with SR{mu}CT and gravimetric data, particularly when volume fraction groups are considered individually.« less

Assessment of bone tissue mineralization by conventional x-ray microcomputed tomography: Comparison with synchrotron radiation microcomputed tomography and ash measurements

PubMed Central

Kazakia, G. J.; Burghardt, A. J.; Cheung, S.; Majumdar, S.

2008-01-01

Assessment of bone tissue mineral density (TMD) may provide information critical to the understanding of mineralization processes and bone biomechanics. High-resolution three-dimensional assessment of TMD has recently been demonstrated using synchrotron radiation microcomputed tomography (SRμCT); however, this imaging modality is relatively inaccessible due to the scarcity of SR facilities. Conventional desktop μCT systems are widely available and have been used extensively to assess bone microarchitecture. However, the polychromatic source and cone-shaped beam geometry complicate assessment of TMD by conventional μCT. The goal of this study was to evaluate μCT-based measurement of degree and distribution of tissue mineralization in a quantitative, spatially resolved manner. Specifically, μCT measures of bone mineral content (BMC) and TMD were compared to those obtained by SRμCT and gravimetric methods. Cylinders of trabecular bone were machined from human femoral heads (n=5), vertebrae (n=5), and proximal tibiae (n=4). Cylinders were imaged in saline on a polychromatic μCT system at an isotropic voxel size of 8 μm. Volumes were reconstructed using beam hardening correction algorithms based on hydroxyapatite (HA)-resin wedge phantoms of 200 and 1200 mg HA∕cm3. SRμCT imaging was performed at an isotropic voxel size of 7.50 μm at the National Synchrotron Light Source. Attenuation values were converted to HA concentration using a linear regression derived by imaging a calibration phantom. Architecture and mineralization parameters were calculated from the image data. Specimens were processed using gravimetric methods to determine ash mass and density. μCT-based BMC values were not affected by altering the beam hardening correction. Volume-averaged TMD values calculated by the two corrections were significantly different (p=0.008) in high volume fraction specimens only, with the 1200 mg HA∕cm3 correction resulting in a 4.7% higher TMD value. μCT and SRμCT provided significantly different measurements of both BMC and TMD (p<0.05). In high volume fraction specimens, μCT with 1200 mg HA∕cm3 correction resulted in BMC and TMD values 16.7% and 15.0% lower, respectively, than SRμCT values. In low volume fraction specimens, μCT with 1200 mg HA∕cm3 correction resulted in BMC and TMD values 12.8% and 12.9% lower, respectively, than SRμCT values. μCT and SRμCT values were well-correlated when volume fraction groups were considered individually (BMC R2=0.97−1.00; TMD R2=0.78−0.99). Ash mass and density were higher than the SRμCT equivalents by 8.6% in high volume fraction specimens and 10.9% in low volume fraction specimens (p<0.05). BMC values calculated by tomography were highly correlated with ash mass (ash versus μCT R2=0.96−1.00; ash versus SRμCT R2=0.99−1.00). TMD values calculated by tomography were moderately correlated with ash density (ash versus μCT R2=0.64−0.72; ash versus SRμCT R2=0.64). Spatially resolved comparisons highlighted substantial geometric nonuniformity in the μCT data, which were reduced (but not eliminated) using the 1200 mg HA∕cm3 beam hardening correction, and did not exist in the SRμCT data. This study represents the first quantitative comparison of μCT mineralization evaluation against SRμCT and gravimetry. Our results indicate that μCT mineralization measures are underestimated but well-correlated with SRμCT and gravimetric data, particularly when volume fraction groups are considered individually. PMID:18697542

Validation of two-dimensional and three-dimensional measurements of subpleural alveolar size parameters by optical coherence tomography

PubMed Central

Warger, William C.; Hostens, Jeroen; Namati, Eman; Birngruber, Reginald; Bouma, Brett E.; Tearney, Guillermo J.

2012-01-01

Abstract. Optical coherence tomography (OCT) has been increasingly used for imaging pulmonary alveoli. Only a few studies, however, have quantified individual alveolar areas, and the validity of alveolar volumes represented within OCT images has not been shown. To validate quantitative measurements of alveoli from OCT images, we compared the cross-sectional area, perimeter, volume, and surface area of matched subpleural alveoli from microcomputed tomography (micro-CT) and OCT images of fixed air-filled swine samples. The relative change in size between different alveoli was extremely well correlated (r>0.9, P<0.0001), but OCT images underestimated absolute sizes compared to micro-CT by 27% (area), 7% (perimeter), 46% (volume), and 25% (surface area) on average. We hypothesized that the differences resulted from refraction at the tissue–air interfaces and developed a ray-tracing model that approximates the reconstructed alveolar size within OCT images. Using this model and OCT measurements of the refractive index for lung tissue (1.41 for fresh, 1.53 for fixed), we derived equations to obtain absolute size measurements of superellipse and circular alveoli with the use of predictive correction factors. These methods and results should enable the quantification of alveolar sizes from OCT images in vivo. PMID:23235834

Validation of two-dimensional and three-dimensional measurements of subpleural alveolar size parameters by optical coherence tomography

NASA Astrophysics Data System (ADS)

Unglert, Carolin I.; Warger, William C.; Hostens, Jeroen; Namati, Eman; Birngruber, Reginald; Bouma, Brett E.; Tearney, Guillermo J.

2012-12-01

Optical coherence tomography (OCT) has been increasingly used for imaging pulmonary alveoli. Only a few studies, however, have quantified individual alveolar areas, and the validity of alveolar volumes represented within OCT images has not been shown. To validate quantitative measurements of alveoli from OCT images, we compared the cross-sectional area, perimeter, volume, and surface area of matched subpleural alveoli from microcomputed tomography (micro-CT) and OCT images of fixed air-filled swine samples. The relative change in size between different alveoli was extremely well correlated (r>0.9, P<0.0001), but OCT images underestimated absolute sizes compared to micro-CT by 27% (area), 7% (perimeter), 46% (volume), and 25% (surface area) on average. We hypothesized that the differences resulted from refraction at the tissue-air interfaces and developed a ray-tracing model that approximates the reconstructed alveolar size within OCT images. Using this model and OCT measurements of the refractive index for lung tissue (1.41 for fresh, 1.53 for fixed), we derived equations to obtain absolute size measurements of superellipse and circular alveoli with the use of predictive correction factors. These methods and results should enable the quantification of alveolar sizes from OCT images in vivo.

In-depth morphological study of mesiobuccal root canal systems in maxillary first molars: review

PubMed Central

Chang, Seok-Woo; Lee, Jong-Ki; Lee, Yoon

2013-01-01

A common failure in endodontic treatment of the permanent maxillary first molars is likely to be caused by an inability to locate, clean, and obturate the second mesiobuccal (MB) canals. Because of the importance of knowledge on these additional canals, there have been numerous studies which investigated the maxillary first molar MB root canal morphology using in vivo and laboratory methods. In this article, the protocols, advantages and disadvantages of various methodologies for in-depth study of maxillary first molar MB root canal morphology were discussed. Furthermore, newly identified configuration types for the establishment of new classification system were suggested based on two image reformatting techniques of micro-computed tomography, which can be useful as a further 'Gold Standard' method for in-depth morphological study of complex root canal systems. PMID:23493453

Assessment of Venous Thrombosis in Animal Models.

PubMed

Grover, Steven P; Evans, Colin E; Patel, Ashish S; Modarai, Bijan; Saha, Prakash; Smith, Alberto

2016-02-01

Deep vein thrombosis and common complications, including pulmonary embolism and post-thrombotic syndrome, represent a major source of morbidity and mortality worldwide. Experimental models of venous thrombosis have provided considerable insight into the cellular and molecular mechanisms that regulate thrombus formation and subsequent resolution. Here, we critically appraise the ex vivo and in vivo techniques used to assess venous thrombosis in these models. Particular attention is paid to imaging modalities, including magnetic resonance imaging, micro-computed tomography, and high-frequency ultrasound that facilitate longitudinal assessment of thrombus size and composition. © 2015 American Heart Association, Inc.

Micro-computed tomographic comparison of nickel-titanium rotary versus traditional instruments in C-shaped root canal system.

PubMed

Yin, Xingzhe; Cheung, Gary Shun-Pan; Zhang, Chengfei; Masuda, Yoshiko Murakami; Kimura, Yuichi; Matsumoto, Koukichi

2010-04-01

The purpose of this study was to assess the efficacy of instrumentation of C-shaped canals with ProTaper rotary system and traditional instruments by using micro-computed tomography (micro-CT). Twenty-four mandibular molars with C-shaped canals were selected in pairs and sorted equally into 2 groups, which were assigned for instrumentation by ProTaper rotary system (ProTaper group) or by K-files and Gates-Glidden burs (Hand Instrument group). Three-dimensional images were constructed by micro-CT. The volume of dentin removed, uninstrumented canal area, time taken for instrumentation, and iatrogenic error of instrumentation were investigated. Hand Instrument group showed greater amount of volumetric dentin removal and left less uninstrumented canal area than ProTaper group (P < .01). The time needed for instrumentation was shorter for ProTaper group than for Hand Instrument group (P < .05). No instrument breakage occurred in both groups, but more conspicuous procedural errors were detected in Hand Instrument group than for ProTaper group. It was concluded that ProTaper rotary system maintained the canal curvature with speediness and few procedural errors, whereas traditional instrumentation can clean more canal surface. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effects of Monoclonal Antibodies against Nerve Growth Factor on Healthy Bone and Joint Tissues in Mice, Rats, and Monkeys: Histopathologic, Biomarker, and Microcomputed Tomographic Assessments.

PubMed

Gropp, Kathryn E; Carlson, Cathy S; Evans, Mark G; Bagi, Cedo M; Reagan, William J; Hurst, Susan I; Shelton, David L; Zorbas, Mark A

2018-01-01

Tanezumab, an anti-nerve growth factor (NGF) antibody, is in development for management of chronic pain. During clinical trials of anti-NGF antibodies, some patients reported unexpected adverse events requiring total joint replacements, resulting in a partial clinical hold on all NGF inhibitors. Three nonclinical toxicology studies were conducted to evaluate the effects of tanezumab or the murine precursor muMab911 on selected bone and joint endpoints and biomarkers in cynomolgus monkeys, Sprague-Dawley rats, and C57BL/6 mice. Joint and bone endpoints included histology, immunohistochemistry, microcomputed tomography (mCT) imaging, and serum biomarkers of bone physiology. Responses of bone endpoints to tanezumab were evaluated in monkeys at 4 to 30 mg/kg/week for 26 weeks and in rats at 0.2 to 10 mg/kg twice weekly for 28 days. The effects of muMab911 at 10 mg/kg/week for 12 weeks on selected bone endpoints were determined in mice. Tanezumab and muMab911 had no adverse effects on any bone or joint parameter. There were no test article-related effects on bone or joint histology, immunohistochemistry, or structure. Reversible, higher osteocalcin concentrations occurred only in the rat study. No deleterious effects were observed in joints or bones in monkeys, rats, or mice administered high doses of tanezumab or muMab911.

Micromechanics of Sea Urchin spines.

PubMed

Tsafnat, Naomi; Fitz Gerald, John D; Le, Hai N; Stachurski, Zbigniew H

2012-01-01

The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spine's unique porous structure, based on micro-computed tomography (microCT) and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spine's architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material.

Preparation and quantification of radioactive particles for tracking hydrodynamic behavior in multiphase reactors.

PubMed

Yunos, Mohd Amirul Syafiq Mohd; Hussain, Siti Aslina; Yusoff, Hamdan Mohamed; Abdullah, Jaafar

2014-09-01

Radioactive particle tracking (RPT) has emerged as a promising and versatile technique that can provide rich information about a variety of multiphase flow systems. However, RPT is not an off-the-shelf technique, and thus, users must customize RPT for their applications. This paper presents a simple procedure for preparing radioactive tracer particles created via irradiation with neutrons from the TRIGA Mark II research reactor. The present study focuses on the performance evaluation of encapsulated gold and scandium particles for applications as individual radioactive tracer particles using qualitative and quantitative neutron activation analysis (NAA) and an X-ray microcomputed tomography (X-ray Micro-CT) scanner installed at the Malaysian Nuclear Agency. Copyright © 2014 Elsevier Ltd. All rights reserved.

Final report : evaluation of microcomputer applications in transportation engineering.

DOT National Transportation Integrated Search

1984-01-01

This study investigated areas where microcomputers can aid in the effectiveness of transportation engineering at state and local levels. A survey of the microcomputer needs of transportation professionals in state and local agencies in Virginia was c...

The Impact of Microcomputer-Based Science Labs on Children's Graphing Skills.

ERIC Educational Resources Information Center

Mokros, Janice R.

Microcomputer-based laboratories (MBL), the use of microcomputers for student-directed data acquisition and analysis, represents a promising new development in science laboratory instruction. This descriptive study determined the impact of MBLs on middle school students' understanding of graphs of distance and velocity. The study was based on the…

Fast laboratory-based micro-computed tomography for pore-scale research: Illustrative experiments and perspectives on the future

NASA Astrophysics Data System (ADS)

Bultreys, Tom; Boone, Marijn A.; Boone, Matthieu N.; De Schryver, Thomas; Masschaele, Bert; Van Hoorebeke, Luc; Cnudde, Veerle

2016-09-01

Over the past decade, the wide-spread implementation of laboratory-based X-ray micro-computed tomography (micro-CT) scanners has revolutionized both the experimental and numerical research on pore-scale transport in geological materials. The availability of these scanners has opened up the possibility to image a rock's pore space in 3D almost routinely to many researchers. While challenges do persist in this field, we treat the next frontier in laboratory-based micro-CT scanning: in-situ, time-resolved imaging of dynamic processes. Extremely fast (even sub-second) micro-CT imaging has become possible at synchrotron facilities over the last few years, however, the restricted accessibility of synchrotrons limits the amount of experiments which can be performed. The much smaller X-ray flux in laboratory-based systems bounds the time resolution which can be attained at these facilities. Nevertheless, progress is being made to improve the quality of measurements performed on the sub-minute time scale. We illustrate this by presenting cutting-edge pore scale experiments visualizing two-phase flow and solute transport in real-time with a lab-based environmental micro-CT set-up. To outline the current state of this young field and its relevance to pore-scale transport research, we critically examine its current bottlenecks and their possible solutions, both on the hardware and the software level. Further developments in laboratory-based, time-resolved imaging could prove greatly beneficial to our understanding of transport behavior in geological materials and to the improvement of pore-scale modeling by providing valuable validation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jakubowicz, J., E-mail: jaroslaw.jakubowicz@put.poznan.pl; Adamek, G.; Pałka, K.

The paper describes the formation, morphology and mechanical properties of Ti void composites. The Ti void composites were made using 100 and 325 mesh Ti powder for solid scaffold formation. The spherical and polyhedral voids (pores) were formed using saccharose particles (table sugar) of different shapes. The Ti void composite morphology was investigated by microcomputed tomography and scanning electron microscopy. The Ti void composites of designed porosity of 50–70% were made. Compression test was applied for mechanical properties estimation. It has been found, that Ti void composites made from 100 mesh Ti and those having spherical pores have a highermore » strength and elastic modulus, i.e. for the designed porosity of 50% for 100 and 325 mesh Ti void composites, a compressive strength was 32.32 and 20.13 MPa, respectively. It has been shown that this is related to better sintering of the 100 mesh Ti powders compared with the 325 mesh Ti powders. A correlation between microcomputed tomography data and mechanical properties has also been shown. The Ti void composites, made with the use of saccharose as a space holder, described in this work should be a promising material for biomedical applications, where interconnected pores and good mechanical properties are required. - Highlights: • Ti scaffolds of the porosity of 50–70% were made. • Saccharose particles as space holder were applied. • The voids in the scaffolds were designed with spherical and polyhedral shape. • The scaffold structure was investigated by SEM and micro-CT. • Micro-CT data and mechanical properties of the Ti scaffold have been correlated.« less

Accurate micro-computed tomography imaging of pore spaces in collagen-based scaffold.

PubMed

Zidek, Jan; Vojtova, Lucy; Abdel-Mohsen, A M; Chmelik, Jiri; Zikmund, Tomas; Brtnikova, Jana; Jakubicek, Roman; Zubal, Lukas; Jan, Jiri; Kaiser, Jozef

2016-06-01

In this work we have used X-ray micro-computed tomography (μCT) as a method to observe the morphology of 3D porous pure collagen and collagen-composite scaffolds useful in tissue engineering. Two aspects of visualizations were taken into consideration: improvement of the scan and investigation of its sensitivity to the scan parameters. Due to the low material density some parts of collagen scaffolds are invisible in a μCT scan. Therefore, here we present different contrast agents, which increase the contrast of the scanned biopolymeric sample for μCT visualization. The increase of contrast of collagenous scaffolds was performed with ceramic hydroxyapatite microparticles (HAp), silver ions (Ag(+)) and silver nanoparticles (Ag-NPs). Since a relatively small change in imaging parameters (e.g. in 3D volume rendering, threshold value and μCT acquisition conditions) leads to a completely different visualized pattern, we have optimized these parameters to obtain the most realistic picture for visual and qualitative evaluation of the biopolymeric scaffold. Moreover, scaffold images were stereoscopically visualized in order to better see the 3D biopolymer composite scaffold morphology. However, the optimized visualization has some discontinuities in zoomed view, which can be problematic for further analysis of interconnected pores by commonly used numerical methods. Therefore, we applied the locally adaptive method to solve discontinuities issue. The combination of contrast agent and imaging techniques presented in this paper help us to better understand the structure and morphology of the biopolymeric scaffold that is crucial in the design of new biomaterials useful in tissue engineering.

Evaluation of a new mid-scala cochlear implant electrode using microcomputed tomography.

PubMed

Frisch, Christopher D; Carlson, Matthew L; Lane, John I; Driscoll, Colin L W

2015-12-01

To investigate electrode position, depth of insertion, and electrode contact using an electrode array with a mid-scala design following round window (RW) and cochleostomy insertion. Eight fresh-frozen cadaveric bones were implanted; half via a RW approach and half through an anteroinferior cochleostomy using a styleted mid-scala electrode design. Microcomputed tomography was used to acquire oblique coronal and oblique axial reformations. Individual electrode positions along each array, insertional depth, and electrode contact were determined using National Institutes of Health Image J software. All electrodes were inserted without significant resistance. The average angular depth of insertion was 436.5° for the RW group and 422.7° for the cochleostomy group. All electrodes acquired a perimodiolar position in the proximal segment and a lateral wall position at the basal turn, regardless of approach. Electrodes distal to the basal turn demonstrated a variable location, with 78% mid scala. One cochleostomy array fractured through the interscalar partition (ISP), acquiring a scala vestibuli position. The odds ratio for either abutting the modiolus, ISP, lateral wall or floor, or fracturing through the ISP were 2.7 times more likely following a cochleostomy insertion (P = .032). The styleted mid-scala electrode design acquires a proximal perimodiolar position, a lateral wall location, as it traverses the basal turn, and most commonly a mid-scala position in the distal array. Interscalar excursion occurred in one of the cochleostomy insertions. Cochleostomy insertion is more likely to result in ultimate final electrode position adjacent to critical intracochlear structures. NA. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Notch3 as a novel therapeutic target in metastatic medullary thyroid cancer.

PubMed

Lou, Irene; Odorico, Scott; Yu, Xiao-Min; Harrison, April; Jaskula-Sztul, Renata; Chen, Herbert

2018-01-01

Medullary thyroid cancer portends poor survival once liver metastasis occurs. We hypothesize that Notch3 overexpression in medullary thyroid cancer liver metastasis will decrease proliferation and growth of the tumor. TT cells were modified genetically to overexpress Notch3 in the presence of doxycycline, creating the TT-Notch3 cell line. Mice were injected intrasplenically with either TT-Notch3 or control vector TT-TRE cells. Each cell line had 3 treatment groups: control with 12 weeks of standard chow, early DOX with doxycycline chow at day 0 and for 70 days thereafter, and late DOX with doxycycline chow at 8 weeks. Each animal underwent micro-computed tomography to evaluate for tumor formation and tumor quantification was performed. Animals were killed at 12 weeks, and the harvested liver was stained with Ki-67, hematoxylin and eosin, and Notch3. Induction of Notch3 did not prevent formation of medullary thyroid cancer liver metastases as all mice in the early DOX group developed tumors. However, induction of Notch after medullary thyroid cancer liver tumor formation decreased tumor size, as seen on micro-computed tomography scans (late DOX group). This translated to a 37-fold decrease in tumor volume (P = .001). Notch3 overexpression also resulted in decreased Ki-67 index (P = .038). Moreover, Notch3 induction led to increased areas of neutrophil infiltration and necrosis on hematoxylin and eosin staining of the tumors CONCLUSION: Notch3 overexpression demonstrates an antiproliferative effect on established metastatic medullary thyroid cancer liver tumors and is a potential therapeutic target in treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of alendronate on restoration of biomechanical properties of periodontium in replanted rat molars.

PubMed

Shibata, T; Komatsu, K; Shimada, A; Shimoda, S; Oida, S; Kawasaki, K; Chiba, M

2004-12-01

We examined the effect of the pretreatment of roots with alendronate on the restoration of the support function of the healing periodontal ligament in replanted rat molars. The left maxillary first molars were extracted, placed in 0.9% NaCl containing 1 mm alendronate (alendronate group) or 0.9% NaCl (control group) for 5 min, and were replanted into their sockets. Groups of animals were killed at 7, 14, and 21 days after replantation. Normal control rats were also killed on the same days. The force required to extract the replanted or normal tooth from its socket was measured, and a load-deformation curve was developed and analyzed. Micro-computed tomography and histologic analyses were also made. The mechanical properties of the healing periodontal ligament in the alendronate group were gradually restored from 7 to 21 days. However, fractures of the roots and bones during mechanical testing occurred in most of the replanted teeth in the control group at 21 days. The rates of restoration of the mechanical strength, extensibility, stiffness, and toughness for the alendronate group at 21 days were 67, 98, 74, and 68% of the normal controls, respectively. Micro-computed tomography and histologic observations revealed that bone-like structures within the pulp and ankylosis between the roots and socket bones occurred commonly in the control group, but were uncommon in the alendronate group. Our findings suggest that the pretreatment with alendronate inhibits the formation of abnormal mineralized tissues and results in better restoration of the support function of the healing periodontal ligament in replanted teeth. (c)Blackwell Munksgaard 2004

Radiological and micro-computed tomography analysis of the bone at dental implants inserted 2, 3 and 4 mm apart in a minipig model with platform switching incorporated.

PubMed

Elian, Nicolas; Bloom, Mitchell; Dard, Michel; Cho, Sang-Choon; Trushkowsky, Richard D; Tarnow, Dennis

2014-02-01

The purpose of this study was to assess the effect of inter-implant distance on interproximal bone utilizing platform switching. Analysis of interproximal bone usually depends on traditional two-dimensional radiographic assessment. Although there has been increased reliability of current techniques, there has been an inability to track bone level changes over time and in three dimensions. Micro-CT has provided three-dimensional imaging that can be used in conjunction with traditional two-dimensional radiographic techniques. This study was performed on 24 female minipigs. Twelve animals received three implants with an inter-implant distance of 3 mm on one side of the mandible and another three implants on the contra-lateral side, where the implants were placed 2 mm apart creating a split mouth design. Twelve other animals received three implants with an inter-implant distance of 3 mm on one side of the mandible and another three implants on the contra-lateral side, where the implants were placed 4 mm apart creating a split mouth design too. The quantitative evaluation was performed comparatively on radiographs taken at t 0 (immediately after implantation) and at t 8 weeks (after termination). The samples were scanned by micro-computed tomography (μCT) to quantify the first bone to implant contact (fBIC) and bone volume/total volume (BV/TV). Mixed model regressions using the nonparametric Brunner-Langer method were used to determine the effect of inter-implant distance on the measured outcomes. The change in bone level was determined using radiography and its mean was 0.05 mm for an inter-implant distance of 3 and 0.00 mm for a 2 mm distance (P = 0.7268). The mean of this outcome was 0.18 mm for the 3 mm and for 4 mm inter-implant distance (P = 0.9500). Micro-computed tomography showed that the fBIC was always located above the reference, 0.27 and 0.20 mm for the comparison of 2-3 mm (P = 0.4622) and 0.49 and 0.34 mm for the inter-implant distance of 3 and 4 mm (P = 0.1699). BV/TV inside the defined parallelepipedic masks reached 82.38% for the 2 mm inter-implant distance and 85.00% for 3 mm, P = 0.8432. For the comparison of the 3-4 mm inter-implant distance, the means were 84.69% and 84.38%, respectively, P = 0.8401. Non-inferiority tests for the smaller inter-implant distances for both comparisons showed similar differences and similar tolerance ranges. The effect of a smaller interproximal distances between implants on bone level, fBIC and BV/TV assessed by two convergent investigation methods, radiology and μCT, was similar to that of larger distances. Implants can potentially be placed 2 mm apart instead of 3 mm and 3 mm apart instead of 4 mm when platform switching is utilized. Further research with a conventional platform is warranted. © 2012 John Wiley & Sons A/S.

Hand and nickel-titanium root canal instrumentation performed by dental students: a micro-computed tomographic study.

PubMed

Peru, M; Peru, C; Mannocci, F; Sherriff, M; Buchanan, L S; Pitt Ford, T R

2006-02-01

The aim of this study was to evaluate root canals instrumented by dental students using the modified double-flared technique, nickel-titanium (NiTi) rotary System GT files and NiTi rotary ProTaper files by micro-computed tomography (MCT). A total of 36 root canals from 18 mesial roots of mandibular molar teeth were prepared; 12 canals were prepared with the modified double-flared technique, using K-flexofiles and Gates-Glidden burs; 12 canals were prepared using System GT and 12 using ProTaper rotary files. Each root was scanned using MCT preoperatively and postoperatively. At the coronal and mid-root sections, System GT and ProTaper files produced significantly less enlarged canal cross-sectional area, volume and perimeter than the modified double-flared technique (P < 0.05). In the mid-root sections there was significantly less thinning of the root structure towards the furcation with System GT and ProTaper (P < 0.05). The rotary techniques were both three times faster than the modified double-flared technique (P < 0.05). Qualitative evaluation of the preparations showed that both ProTaper and System GT were able to prepare root canals with little or no procedural error compared with the modified double-flared technique. Under the conditions of this study, inexperienced dental students were able to prepare curved root canals with rotary files with greater preservation of tooth structure, low risk of procedural errors and much quicker than with hand instruments.

The dynamic micro computed tomography at SSRF

NASA Astrophysics Data System (ADS)

Chen, R.; Xu, L.; Du, G.; Deng, B.; Xie, H.; Xiao, T.

2018-05-01

Synchrotron radiation micro-computed tomography (SR-μCT) is a critical technique for quantitative characterizing the 3D internal structure of samples, recently the dynamic SR-μCT has been attracting vast attention since it can evaluate the three-dimensional structure evolution of a sample. A dynamic μCT method, which is based on monochromatic beam, was developed at the X-ray Imaging and Biomedical Application Beamline at Shanghai Synchrotron Radiation Facility, by combining the compressed sensing based CT reconstruction algorithm and hardware upgrade. The monochromatic beam based method can achieve quantitative information, and lower dose than the white beam base method in which the lower energy beam is absorbed by the sample rather than contribute to the final imaging signal. The developed method is successfully used to investigate the compression of the air sac during respiration in a bell cricket, providing new knowledge for further research on the insect respiratory system.

Enabling three-dimensional densitometric measurements using laboratory source X-ray micro-computed tomography

NASA Astrophysics Data System (ADS)

Pankhurst, M. J.; Fowler, R.; Courtois, L.; Nonni, S.; Zuddas, F.; Atwood, R. C.; Davis, G. R.; Lee, P. D.

2018-01-01

We present new software allowing significantly improved quantitative mapping of the three-dimensional density distribution of objects using laboratory source polychromatic X-rays via a beam characterisation approach (c.f. filtering or comparison to phantoms). One key advantage is that a precise representation of the specimen material is not required. The method exploits well-established, widely available, non-destructive and increasingly accessible laboratory-source X-ray tomography. Beam characterisation is performed in two stages: (1) projection data are collected through a range of known materials utilising a novel hardware design integrated into the rotation stage; and (2) a Python code optimises a spectral response model of the system. We provide hardware designs for use with a rotation stage able to be tilted, yet the concept is easily adaptable to virtually any laboratory system and sample, and implicitly corrects the image artefact known as beam hardening.

Novel fusion for hybrid optical/microcomputed tomography imaging based on natural light surface reconstruction and iterated closest point

NASA Astrophysics Data System (ADS)

Ning, Nannan; Tian, Jie; Liu, Xia; Deng, Kexin; Wu, Ping; Wang, Bo; Wang, Kun; Ma, Xibo

2014-02-01

In mathematics, optical molecular imaging including bioluminescence tomography (BLT), fluorescence tomography (FMT) and Cerenkov luminescence tomography (CLT) are concerned with a similar inverse source problem. They all involve the reconstruction of the 3D location of a single/multiple internal luminescent/fluorescent sources based on 3D surface flux distribution. To achieve that, an accurate fusion between 2D luminescent/fluorescent images and 3D structural images that may be acquired form micro-CT, MRI or beam scanning is extremely critical. However, the absence of a universal method that can effectively convert 2D optical information into 3D makes the accurate fusion challengeable. In this study, to improve the fusion accuracy, a new fusion method for dual-modality tomography (luminescence/fluorescence and micro-CT) based on natural light surface reconstruction (NLSR) and iterated closest point (ICP) was presented. It consisted of Octree structure, exact visual hull from marching cubes and ICP. Different from conventional limited projection methods, it is 360° free-space registration, and utilizes more luminescence/fluorescence distribution information from unlimited multi-orientation 2D optical images. A mouse mimicking phantom (one XPM-2 Phantom Light Source, XENOGEN Corporation) and an in-vivo BALB/C mouse with implanted one luminescent light source were used to evaluate the performance of the new fusion method. Compared with conventional fusion methods, the average error of preset markers was improved by 0.3 and 0.2 pixels from the new method, respectively. After running the same 3D internal light source reconstruction algorithm of the BALB/C mouse, the distance error between the actual and reconstructed internal source was decreased by 0.19 mm.

A study of the selection of microcomputer architectures to automate planetary spacecraft power systems

NASA Technical Reports Server (NTRS)

Nauda, A.

1982-01-01

Performance and reliability models of alternate microcomputer architectures as a methodology for optimizing system design were examined. A methodology for selecting an optimum microcomputer architecture for autonomous operation of planetary spacecraft power systems was developed. Various microcomputer system architectures are analyzed to determine their application to spacecraft power systems. It is suggested that no standardization formula or common set of guidelines exists which provides an optimum configuration for a given set of specifications.

Combination of platelet-rich plasma with degradable bioactive borate glass for segmental bone defect repair.

PubMed

Zhang, Ya-Dong; Wang, Gang; Sun, Yan; Zhang, Chang-Qing

2011-02-01

Porous scaffold biomaterials may offer a clinical alternative to bone grafts; however, scaffolds alone are typically insufficient to heal large bone defects. Numerous studies have demonstrated that osteoinductive growth factor significantly improves bone repair. In this study, a strategy combining degradable bioactive borate glass (BG) scaffolds with platelet-rich plasma (PRP) was tested. The bone defect was filled with BG alone, BG combined with autologous PRP or left empty. Bone formation was analyzed at 4, 8 and 12 weeks using both histology and radiology. The PRP treated group yielded better bone formation than the pure BG scaffold as determined by both histology and microcomputer tomography after 12 weeks. In conclusion, PRP improved bone healing in a diaphyseal rabbit model on BG. The combination of PRP and BG may be an effective approach to repair critical defects.

Determination of the Dynamics of Healing at the Tissue-Implant Interface by Means of Microcomputed Tomography and Functional Apparent Moduli

PubMed Central

Chang, Po-Chun; Seol, Yang-Jo; Goldstein, Steven A.; Giannobile, William V.

2014-01-01

Purpose It is currently a challenge to determine the biomechanical properties of the hard tissue–dental implant interface. Recent advances in intraoral imaging and tomographic methods, such as microcomputed tomography (micro-CT), provide three-dimensional details, offering significant potential to evaluate the bone-implant interface, but yield limited information regarding osseointegration because of physical scattering effects emanating from metallic implant surfaces. In the present study, it was hypothesized that functional apparent moduli (FAM), generated from functional incorporation of the peri-implant structure, would eliminate the radiographic artifact–affected layer and serve as a feasible means to evaluate the biomechanical dynamics of tissue-implant integration in vivo. Materials and Methods Cylindric titanium mini-implants were placed in osteotomies and osteotomies with defects in rodent maxillae. The layers affected by radiographic artifacts were identified, and the pattern of tissue-implant integration was evaluated from histology and micro-CT images over a 21-day observation period. Analyses of structural information, FAM, and the relationship between FAM and interfacial stiffness (IS) were done before and after eliminating artifacts. Results Physical artifacts were present within a zone of about 100 to 150 μm around the implant in both experimental defect situations (osteotomy alone and osteotomy + defect). All correlations were evaluated before and after eliminating the artifact-affected layers, most notably during the maturation period of osseointegration. A strong correlation existed between functional bone apparent modulus and IS within 300 μm at the osteotomy defects (r > 0.9) and functional composite tissue apparent modulus in the osteotomy defects (r > 0.75). Conclusion Micro-CT imaging and FAM were of value in measuring the temporal process of tissue-implant integration in vivo. This approach will be useful to complement imaging technologies for longitudinal monitoring of osseointegration. PMID:23377049

Novel injectable gellan gum hydrogel composites incorporating Zn- and Sr-enriched bioactive glass microparticles: High-resolution X-ray microcomputed tomography, antibacterial and in vitro testing.

PubMed

Douglas, Timothy E L; Dziadek, Michal; Gorodzha, Svetlana; Lišková, Jana; Brackman, Gilles; Vanhoorne, Valérie; Vervaet, Chris; Balcaen, Lieve; Del Rosario Florez Garcia, Maria; Boccaccini, Aldo R; Weinhardt, Venera; Baumbach, Tilo; Vanhaecke, Frank; Coenye, Tom; Bačáková, Lucie; Surmeneva, Maria A; Surmenev, Roman A; Cholewa-Kowalska, Katarzyna; Skirtach, Andre G

2018-06-01

Mineralization of hydrogel biomaterials is desirable to improve their suitability as materials for bone regeneration. In this study, gellan gum (GG) hydrogels were formed by simple mixing of GG solution with bioactive glass microparticles of 45S5 composition, leading to hydrogel formation by ion release from the amorphous bioactive glass microparticles. This resulted in novel injectable, self-gelling composites of GG hydrogels containing 20% bioactive glass. Gelation occurred within 20 min. Composites containing the standard 45S5 bioactive glass preparation were markedly less stiff. X-ray microcomputed tomography proved to be a highly sensitive technique capable of detecting microparticles of diameter approximately 8 μm, that is, individual microparticles, and accurately visualizing the size distribution of bioactive glass microparticles and their aggregates, and their distribution in GG hydrogels. The widely used melt-derived 45S5 preparation served as a standard and was compared with a calcium-rich, sol-gel derived preparation (A2), as well as A2 enriched with zinc (A2Zn5) and strontium (A2Sr5). A2, A2Zn, and A2Sr bioactive glass particles were more homogeneously dispersed in GG hydrogels than 45S5. Composites containing all four bioactive glass preparations exhibited antibacterial activity against methicillin-resistant Staphylococcus aureus. Composites containing A2Zn5 and A2Sr5 bioactive glasses supported the adhesion and growth of osteoblast-like cells and were considerably more cytocompatible than 45S5. All composites underwent mineralization with calcium-deficient hydroxyapatite upon incubation in simulated body fluid. The extent of mineralization appeared to be greatest for composites containing A2Zn5 and 45S5. The results underline the importance of the choice of bioactive glass when preparing injectable, self-gelling composites. Copyright © 2018 John Wiley & Sons, Ltd.

A novel approach for studying the temporal modulation of embryonic skeletal development using organotypic bone cultures and microcomputed tomography.

PubMed

Kanczler, Janos M; Smith, Emma L; Roberts, Carol A; Oreffo, Richard O C

2012-10-01

Understanding the structural development of embryonic bone in a three dimensional framework is fundamental to developing new strategies for the recapitulation of bone tissue in latter life. We present an innovative combined approach of an organotypic embryonic femur culture model, microcomputed tomography (μCT) and immunohistochemistry to examine the development and modulation of the three dimensional structures of the developing embryonic femur. Isolated embryonic chick femurs were organotypic (air/liquid interface) cultured for 10 days in either basal, chondrogenic, or osteogenic supplemented culture conditions. The growth development and modulating effects of basal, chondrogenic, or osteogenic culture media of the embryonic chick femurs was investigated using μCT, immunohistochemistry, and histology. The growth and development of noncultured embryonic chick femur stages E10, E11, E12, E13, E15, and E17 were very closely correlated with increased morphometric indices of bone formation as determined by μCT. After 10 days in the organotpyic culture set up, the early aged femurs (E10 and E11) demonstrated a dramatic response to the chondrogenic or osteogenic culture conditions compared to the basal cultured femurs as determined by a change in μCT morphometric indices and modified expression of chondrogenic and osteogenic markers. Although the later aged femurs (E12 and E13) increased in size and structure after 10 days organotpypic culture, the effects of the osteogenic and chondrogenic organotypic cultures on these femurs were not significantly altered compared to basal conditions. We have demonstrated that the embryonic chick femur organotpyic culture model combined with the μCT and immunohistochemical analysis can provide an integral methodology for investigating the modulation of bone development in an ex vivo culture setting. Hence, these interdisciplinary techniques of μCT and whole organ bone cultures will enable us to delineate some of the temporal, structural developmental paradigms and modulation of bone tissue formation to underpin innovative skeletal regenerative technology for clinical therapeutic strategies in musculoskeletal trauma and diseases.

Microcomputed tomography analysis of mesiobuccal orifices and major apical foramen in first maxillary molars.

PubMed

Spagnuolo, Gianrico; Ametrano, Gianluca; D'Antò, Vincenzo; Formisano, Anna; Simeone, Michele; Riccitiello, Francesco; Amato, Massimo; Rengo, Sandro

2012-01-01

Aim of the study was to determined by microcomputed tomography (µCT) the horizontal distance between the main (MB1) and the second mesiobuccal canal (MB2) orifices, the vertical distance between the MB1 and MB2 orifices planes, and the distance between the anatomic apex and major apical foramen (AF). Furthermore, we characterized the entire internal and external anatomy of the MB, distalbuccal (DB) and palatal (P) maxillary first molars roots. Twenty-two intact extracted first maxillary molars were scanned by X-ray computed transaxial µCT and then 2D and 3D images were processed and analyzed. The results showed that 77.27% of the mesiobuccal (MB) roots presented a second MB canal, and 29.41% of the MB2 were independent from the MB1 canals. In 15 teeth, there were three root canal orifices on the chamber floor, and 10 of these teeth presented MB2 canals. The mean vertical distance between the MB1 and MB2 planes was 1.68 ± 0.83 mm. Seven teeth had four orifices. The mean horizontal interorificial distance between the MB1 and MB2 orifices was 1.21 ± 0.5 mm. Accessory canals were observed in 33.33% of the roots, loops in 6.06%, while isthmuses were found in 15 of the 22 MB roots. Of the total roots, 74.24% presented one foramen, while all of the roots showed a major apical foramen that was not coincident with the anatomic apex. Our µCT analysis provided interesting features on the horizontal and vertical distance between the MB1 and MB2 orifices and on the distance of AF and anatomic apex. These results have an important clinical value because might support the endodontist in the recruitment, negotiation and obturation of maxillary first molar canal system.

Microcomputed Tomography Analysis of Mesiobuccal Orifices and Major Apical Foramen in First Maxillary Molars

PubMed Central

Spagnuolo, Gianrico; Ametrano, Gianluca; D’Antò, Vincenzo; Formisano, Anna; Simeone, Michele; Riccitiello, Francesco; Amato, Massimo; Rengo, Sandro

2012-01-01

Objective: Aim of the study was to determined by microcomputed tomography (µCT) the horizontal distance between the main (MB1) and the second mesiobuccal canal (MB2) orifices, the vertical distance between the MB1 and MB2 orifices planes, and the distance between the anatomic apex and major apical foramen (AF). Furthermore, we characterized the entire internal and external anatomy of the MB, distalbuccal (DB) and palatal (P) maxillary first molars roots. Materials and Methods: Twenty-two intact extracted first maxillary molars were scanned by X-ray computed transaxial µCT and then 2D and 3D images were processed and analyzed. Results: The results showed that 77.27% of the mesiobuccal (MB) roots presented a second MB canal, and 29.41% of the MB2 were independent from the MB1 canals. In 15 teeth, there were three root canal orifices on the chamber floor, and 10 of these teeth presented MB2 canals. The mean vertical distance between the MB1 and MB2 planes was 1.68 ± 0.83 mm. Seven teeth had four orifices. The mean horizontal interorificial distance between the MB1 and MB2 orifices was 1.21 ± 0.5 mm. Accessory canals were observed in 33.33% of the roots, loops in 6.06%, while isthmuses were found in 15 of the 22 MB roots. Of the total roots, 74.24% presented one foramen, while all of the roots showed a major apical foramen that was not coincident with the anatomic apex. Conclusions: Our µCT analysis provided interesting features on the horizontal and vertical distance between the MB1 and MB2 orifices and on the distance of AF and anatomic apex. Clinical Relevance: These results have an important clinical value because might support the endodontist in the recruitment, negotiation and obturation of maxillary first molar canal system. PMID:22905069

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.

PubMed

Wu, Andy T J; Turk, Tamer; Colak, Canan; Elekdağ-Turk, Selma; Jones, Allan S; Petocz, Peter; Darendeliler, M Ali

2011-05-01

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. 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. 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). Heavy rotational forces caused more root resorption than light rotational forces and compression areas (buccal-distal and lingual-mesial surfaces in this study) showed significantly higher root resorption than other areas at all levels of the root. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Flow velocity-driven differentiation of human mesenchymal stromal cells in silk fibroin scaffolds: A combined experimental and computational approach

PubMed Central

Betts, Duncan Colin; Müller, Ralph; Hofmann, Sandra

2017-01-01

Mechanical loading plays a major role in bone remodeling and fracture healing. Mimicking the concept of mechanical loading of bone has been widely studied in bone tissue engineering by perfusion cultures. Nevertheless, there is still debate regarding the in-vitro mechanical stimulation regime. This study aims at investigating the effect of two different flow rates (vlow = 0.001m/s and vhigh = 0.061m/s) on the growth of mineralized tissue produced by human mesenchymal stromal cells cultured on 3-D silk fibroin scaffolds. The flow rates applied were chosen to mimic the mechanical environment during early fracture healing or during bone remodeling, respectively. Scaffolds cultured under static conditions served as a control. Time-lapsed micro-computed tomography showed that mineralized extracellular matrix formation was completely inhibited at vlow compared to vhigh and the static group. Biochemical assays and histology confirmed these results and showed enhanced osteogenic differentiation at vhigh whereas the amount of DNA was increased at vlow. The biological response at vlow might correspond to the early stage of fracture healing, where cell proliferation and matrix production is prominent. Visual mapping of shear stresses, simulated by computational fluid dynamics, to 3-D micro-computed tomography data revealed that shear stresses up to 0.39mPa induced a higher DNA amount and shear stresses between 0.55mPa and 24mPa induced osteogenic differentiation. This study demonstrates the feasibility to drive cell behavior of human mesenchymal stromal cells by the flow velocity applied in agreement with mechanical loading mimicking early fracture healing (vlow) or bone remodeling (vhigh). These results can be used in the future to tightly control the behavior of human mesenchymal stromal cells towards proliferation or differentiation. Additionally, the combination of experiment and simulation presented is a strong tool to link biological responses to mechanical stimulation and can be applied to various in-vitro cultures to improve the understanding of the cause-effect relationship of mechanical loading. PMID:28686698

Two Flat-Backed Polydesmidan Millipedes from the Miocene Chiapas-Amber Lagerstätte, Mexico

PubMed Central

Riquelme, Francisco; Hernández-Patricio, Miguel; Martínez-Dávalos, Arnulfo; Rodríguez-Villafuerte, Mercedes; Montejo-Cruz, Maira; Alvarado-Ortega, Jesús; Ruvalcaba-Sil, José L.; Zúñiga-Mijangos, Luis

2014-01-01

Two species of fossil polydesmidan millipedes (Diplopoda: Polydesmida) embedded in amber are described from Miocene strata near Simojovel, in the Chiapas Highlands, Mexico. Maatidesmus paachtun gen. et sp. nov., placed into Chelodesmidae Cook, 1895, and Anbarrhacus adamantis gen. et sp. nov., assigned in the family Platyrhacidae Pocock, 1895. Morphological data from fossil specimens have been recovered using 3D X-ray micro-computed tomography and regular to infrared-reflected microscopy. Both fossil species are recognizable as new primarily but not exclusively, by collum margin modification and remarkable paranotal and metatergite dorsal sculpture. PMID:25162220

Two flat-backed polydesmidan millipedes from the Miocene Chiapas-amber Lagerstätte, Mexico.

PubMed

Riquelme, Francisco; Hernández-Patricio, Miguel; Martínez-Dávalos, Arnulfo; Rodríguez-Villafuerte, Mercedes; Montejo-Cruz, Maira; Alvarado-Ortega, Jesús; Ruvalcaba-Sil, José L; Zúñiga-Mijangos, Luis

2014-01-01

Two species of fossil polydesmidan millipedes (Diplopoda: Polydesmida) embedded in amber are described from Miocene strata near Simojovel, in the Chiapas Highlands, Mexico. Maatidesmus paachtun gen. et sp. nov., placed into Chelodesmidae Cook, 1895, and Anbarrhacus adamantis gen. et sp. nov., assigned in the family Platyrhacidae Pocock, 1895. Morphological data from fossil specimens have been recovered using 3D X-ray micro-computed tomography and regular to infrared-reflected microscopy. Both fossil species are recognizable as new primarily but not exclusively, by collum margin modification and remarkable paranotal and metatergite dorsal sculpture.

Research on Multimedia Access to Microcomputers for Visually Impaired Youth.

ERIC Educational Resources Information Center

Ashcroft, S. C.

This final report discusses the outcomes of a federally funded project that studied visual, auditory, and tactual methods designed to give youth with visual impairments access to microcomputers for curricular, prevocational, and avocational purposes. The objectives of the project were: (1) to research microcomputer systems that could be made…

Microcomputer Application Priorities of College Faculty in Vocational-Technical Education.

ERIC Educational Resources Information Center

Cox, Kenneth; Cheek, Gerald

A literature review revealed that few colleges of education offering courses in microcomputer applications are addressing the training needs of college professors and graduate students aspiring to faculty positions. A study was therefore conducted to define and prioritize microcomputer applications needed by college faculty in vocational-technical…

MICROSPED Information Bulletin, Issues 1-10, 1984. Microcomputers in the Schools--Implementation in Special Education.

ERIC Educational Resources Information Center

Hanley, Tom V., Ed.; And Others

1984-01-01

Ten information bulletins on the implementation of microcomputers in special education are presented. Topics covered include the following: (1) implementation issues (including a description of a study assessing microcomputer applications in 12 local school districts' special education programs); (2) implementation strategies (which focuses on…

Sensitivity and accuracy of hybrid fluorescence-mediated tomography in deep tissue regions.

PubMed

Rosenhain, Stefanie; Al Rawashdeh, Wa'el; Kiessling, Fabian; Gremse, Felix

2017-09-01

Fluorescence-mediated tomography (FMT) enables noninvasive assessment of the three-dimensional distribution of near-infrared fluorescence in mice. The combination with micro-computed tomography (µCT) provides anatomical data, enabling improved fluorescence reconstruction and image analysis. The aim of our study was to assess sensitivity and accuracy of µCT-FMT under realistic in vivo conditions in deeply-seated regions. Accordingly, we acquired fluorescence reflectance images (FRI) and µCT-FMT scans of mice which were prepared with rectal insertions with different amounts of fluorescent dye. Default and high-sensitivity scans were acquired and background signal was analyzed for three FMT channels (670 nm, 745 nm, and 790 nm). Analysis was performed for the original and an improved FMT reconstruction using the µCT data. While FRI and the original FMT reconstruction could detect 100 pmol, the improved FMT reconstruction could detect 10 pmol and significantly improved signal localization. By using a finer sampling grid and increasing the exposure time, the sensitivity could be further improved to detect 0.5 pmol. Background signal was highest in the 670 nm channel and most prominent in the gastro-intestinal tract and in organs with high relative amounts of blood. In conclusion, we show that µCT-FMT allows sensitive and accurate assessment of fluorescence in deep tissue regions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Micromechanics of Sea Urchin Spines

PubMed Central

Tsafnat, Naomi; Fitz Gerald, John D.; Le, Hai N.; Stachurski, Zbigniew H.

2012-01-01

The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spine’s unique porous structure, based on micro-computed tomography (microCT) and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spine’s architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material. PMID:22984468

Three dimensional morphological studies of Larger Benthic Foraminifera at the population level using micro computed tomography

NASA Astrophysics Data System (ADS)

Kinoshita, Shunichi; Eder, Wolfgang; Woeger, Julia; Hohenegger, Johann; Briguglio, Antonino; Ferrandez-Canadell, Carles

2015-04-01

Symbiont-bearing larger benthic Foraminifera (LBF) are long-living marine (at least 1 year), single-celled organisms with complex calcium carbonate shells. Their morphology has been intensively studied since the middle of the nineteenth century. This led to a broad spectrum of taxonomic results, important from biostratigraphy to ecology in shallow water tropical to warm temperate marine palaeo-environments. However, it was necessary for the traditional investigation methods to cut or destruct specimens for analysing the taxonomically important inner structures. X-ray micro-computed tomography (microCT) is one of the newest techniques used in morphological studies. The greatest advantage is the non-destructive acquisition of inner structures. Furthermore, the running improve of microCT scanners' hard- and software provides high resolution and short time scans well-suited for LBF. Three-dimensional imaging techniques allow to select and extract each chamber and to measure easily its volume, surface and several form parameters used for morphometric analyses. Thus, 3-dimensional visualisation of LBF-tests is a very big step forward from traditional morphology based on 2-dimensional data. The quantification of chamber form is a great opportunity to tackle LBF structures, architectures and the bauplan geometry. The micrometric digital resolution is the only way to solve many controversies in phylogeny and evolutionary trends of LBF. For the present study we used micro-computed tomography to easily investigate the chamber number of every specimen from statistically representative part of populations to estimate population dynamics. Samples of living individuals are collected at monthly intervals from fixed locations. Specific preparation allows to scan up to 35 specimens per scan within 2 hours and to obtain the complete digital dataset for each specimen of the population. MicroCT enables thus a fast and precise count of all chambers built by the foraminifer from its birth until the time of collection and to extract selected chambers for further studies. The variation in chamber number during the sampling period (in this study limited at 15 months) will allow the estimation of the mean chamber building rate for each investigated species. However, a number of morphological aberrations within the population can be observed: often multiple proloculi are present; their orientation to the equatorial plane (or planes) respectively the spatial position of the foramina between proloculus (or proloculi) to the reniform deuteroloculi, the geometry of septa and septula and their variation trough ontogeny and several other ontogenetic variation need further attention. Many new insights into the biology of living and fossil LBF will be obtained when the three dimensional morphology of the complete foraminiferal shell is raised to the population level.

The Effects of Microcomputers on Children's Attention to Reading Tasks.

ERIC Educational Resources Information Center

Zuk, Dorie; Danner, Fred

A study investigated the effects of microcomputers on children's attention to reading tasks and the relationship between previous reading achievement and grade level on such attentional behavior. Fifty-five third and fifth graders read two stories each, one presented on a microcomputer and one presented in print. Television cartoons and rock music…

Microcomputer Applications in Secondary Health Occupations Education: State of the Art.

ERIC Educational Resources Information Center

Shelly, Richard W.

A study was undertaken to identify the different ways and the extent to which microcomputers are being used in secondary health occupations education (HOE) programs, the amount and types of applicable software and level of support for microcomputer-based HOE, and available literature reflecting or supporting the development of computer-assisted…

Microcomputers in the Classroom: Don't Exclude the Developmentally Disabled.

ERIC Educational Resources Information Center

Schall, William E.; And Others

1985-01-01

This study tested the hypothesis that 15- to 21-year-old educable mentally retarded students could successfully interact with microcomputers and show interest in using them as a learning tool. High interest levels and attention spans and positive microcomputer attitudes displayed by subjects suggest there may be unrealized potential in…

Cross-sex testosterone therapy in ovariectomized mice: addition of low-dose estrogen preserves bone architecture.

PubMed

Goetz, Laura G; Mamillapalli, Ramanaiah; Devlin, Maureen J; Robbins, Amy E; Majidi-Zolbin, Masoumeh; Taylor, Hugh S

2017-11-01

Cross-sex hormone therapy (XHT) is widely used by transgender people to alter secondary sex characteristics to match their desired gender presentation. Here, we investigate the long-term effects of XHT on bone health using a murine model. Female mice underwent ovariectomy at either 6 or 10 wk and began weekly testosterone or vehicle injections. Dual-energy X-ray absorptiometry (DXA) was performed (20 wk) to measure bone mineral density (BMD), and microcomputed tomography was performed to compare femoral cortical and trabecular bone architecture. The 6-wk testosterone group had comparable BMD with controls by DXA but reduced bone volume fraction, trabecular number, and cortical area fraction and increased trabecular separation by microcomputed tomography. Ten-week ovariectomy/XHT maintained microarchitecture, suggesting that estrogen is critical for bone acquisition during adolescence and that late, but not early, estrogen loss can be sufficiently replaced by testosterone alone. Given these findings, we then compared effects of testosterone with effects of weekly estrogen or combined testosterone/low-dose estrogen treatment after a 6-wk ovariectomy. Estrogen treatment increased spine BMD and microarchitecture, including bone volume fraction, trabecular number, trabecular thickness, and connectivity density, and decreased trabecular separation. Combined testosterone-estrogen therapy caused similar increases in femur and spine BMD and improved architecture (increased bone volume fraction, trabecular number, trabecular thickness, and connectivity density) to estrogen therapy and were superior compared with mice treated with testosterone only. These results demonstrate estradiol is critical for bone acquisition and suggest a new cross-sex hormone therapy adding estrogens to testosterone treatments with potential future clinical implications for treating transgender youth or men with estrogen deficiency. Copyright © 2017 the American Physiological Society.

Poster - Thurs Eve-12: A needle-positioning robot co-registered with volumetric x-ray micro-computed tomography images for minimally-invasive small-animal interventions.

PubMed

Waspe, A C; Holdsworth, D W; Lacefield, J C; Fenster, A

2008-07-01

Preclinical research protocols often require the delivery of biological substances to specific targets in small animal disease models. To target biologically relevant locations in mice accurately, the needle positioning error needs to be < 200 μm. If targeting is inaccurate, experimental results can be inconclusive or misleading. We have developed a robotic manipulator that is capable of positioning a needle with a mean error < 100 μm. An apparatus and method were developed for integrating the needle-positioning robot with volumetric micro-computed tomography image guidance for interventions in small animals. Accurate image-to-robot registration is critical for integration as it enables targets identified in the image to be mapped to physical coordinates inside the animal. Registration is accomplished by injecting barium sulphate into needle tracks as the robot withdraws the needle from target points in a tissue-mimicking phantom. Registration accuracy is therefore affected by the positioning error of the robot and is assessed by measuring the point-to-line fiducial and target registration errors (FRE, TRE). Centroid points along cross-sectional slices of the track are determined using region growing segmentation followed by application of a center-of-mass algorithm. The centerline points are registered to needle trajectories in robot coordinates by applying an iterative closest point algorithm between points and lines. Implementing this procedure with four fiducial needle tracks produced a point-to-line FRE and TRE of 246 ± 58 μm and 194 ± 18 μm, respectively. The proposed registration technique produced a TRE < 200 μm, in the presence of robot positioning error, meeting design specification. © 2008 American Association of Physicists in Medicine.

Integration and evaluation of a needle-positioning robot with volumetric microcomputed tomography image guidance for small animal stereotactic interventions.

PubMed

Waspe, Adam C; McErlain, David D; Pitelka, Vasek; Holdsworth, David W; Lacefield, James C; Fenster, Aaron

2010-04-01

Preclinical research protocols often require insertion of needles to specific targets within small animal brains. To target biologically relevant locations in rodent brains more effectively, a robotic device has been developed that is capable of positioning a needle along oblique trajectories through a single burr hole in the skull under volumetric microcomputed tomography (micro-CT) guidance. An x-ray compatible stereotactic frame secures the head throughout the procedure using a bite bar, nose clamp, and ear bars. CT-to-robot registration enables structures identified in the image to be mapped to physical coordinates in the brain. Registration is accomplished by injecting a barium sulfate contrast agent as the robot withdraws the needle from predefined points in a phantom. Registration accuracy is affected by the robot-positioning error and is assessed by measuring the surface registration error for the fiducial and target needle tracks (FRE and TRE). This system was demonstrated in situ by injecting 200 microm tungsten beads into rat brains along oblique trajectories through a single burr hole on the top of the skull under micro-CT image guidance. Postintervention micro-CT images of each skull were registered with preintervention high-field magnetic resonance images of the brain to infer the anatomical locations of the beads. Registration using four fiducial needle tracks and one target track produced a FRE and a TRE of 96 and 210 microm, respectively. Evaluation with tissue-mimicking gelatin phantoms showed that locations could be targeted with a mean error of 154 +/- 113 microm. The integration of a robotic needle-positioning device with volumetric micro-CT image guidance should increase the accuracy and reduce the invasiveness of stereotactic needle interventions in small animals.

The influence of alendronate on the healing of extraction sockets of ovariectomized rats assessed by in vivo micro-computed tomography.

PubMed

Jee, Jeong-Hyun; Lee, Wan; Lee, Byung Do

2010-08-01

Many dental patients take bisphosphonates to reduce the risk of hip and vertebral fractures. In vivo micro-computed tomography (micro-CT) was used to examine the longitudinal inhibitory effect of alendronate on the healing of extraction sockets in ovariectomized rats. Twenty 5-week-old Sprague-Dawley rats were assigned randomly to 1 of 3 groups: sham-operated (n = 5), and 2 ovariectomized (OVX) groups: saline treated (0.1 mL/100 g/d, n = 7) and alendronate treated (1 mg/kg/d, n = 8). Before micro-CT scanning, the left maxillary first molars of the rats were extracted. In vivo micro-CT (spatial resolution 50 x 50 mum) of the jaw was performed at baseline and at 2-week intervals for 6 weeks. Alveolar-bone radiographic densities and dimensions were analyzed with repeated measures analysis of variance. The bony healing patterns of the extraction sockets were also evaluated in each group. The radiographic socket densities of the sham-treated and OVX-alendronate groups significantly increased during the first 4 weeks after extraction (P < .05). At 2 weeks, the radiographic densities of the sockets in the OVX-saline group increased, but the increase was significantly lower than for the other groups at 4 weeks (P < .05). Newly formed bone was identified in the extraction sockets in all groups 2 to 6 weeks after extraction. There was a significant loss of alveolar ridge height at the second week postextraction compared with baseline, and at the fourth week compared with the second week (P < .05) except in the alendronate group. Alendronate appears to promote the healing of extraction sockets in estrogen-deficient rats and helps resist the loss of alveolar bone adjacent to extraction sockets. Copyright 2010 Mosby, Inc. All rights reserved.

Dual-Energy Micro-Computed Tomography Imaging of Radiation-Induced Vascular Changes in Primary Mouse Sarcomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moding, Everett J.; Clark, Darin P.; Qi, Yi

2013-04-01

Purpose: To evaluate the effects of radiation therapy on primary tumor vasculature using dual-energy (DE) micro-computed tomography (micro-CT). Methods and Materials: Primary sarcomas were generated with mutant Kras and p53. Unirradiated tumors were compared with tumors irradiated with 20 Gy. A liposomal-iodinated contrast agent was administered 1 day after treatment, and mice were imaged immediately after injection (day 1) and 3 days later (day 4) with DE micro-CT. CT-derived tumor sizes were used to assess tumor growth. After DE decomposition, iodine maps were used to assess tumor fractional blood volume (FBV) at day 1 and tumor vascular permeability at daymore » 4. For comparison, tumor vascularity and vascular permeability were also evaluated histologically by use of CD31 immunofluorescence and fluorescently-labeled dextrans. Results: Radiation treatment significantly decreased tumor growth from day 1 to day 4 (P<.05). There was a positive correlation between CT measurement of tumor FBV on day 1 and extravasated iodine on day 4 with microvascular density (MVD) on day 4 (R{sup 2}=0.53) and dextran accumulation (R{sup 2}=0.63) on day 4, respectively. Despite no change in MVD measured by histology, tumor FBV significantly increased after irradiation as measured by DE micro-CT (0.070 vs 0.091, P<.05). Both dextran and liposomal-iodine accumulation in tumors increased significantly after irradiation, with dextran fractional area increasing 5.2-fold and liposomal-iodine concentration increasing 4.0-fold. Conclusions: DE micro-CT is an effective tool for noninvasive assessment of vascular changes in primary tumors. Tumor blood volume and vascular permeability increased after a single therapeutic dose of radiation treatment.« less

Quantitative 3D analysis of the canal network in cortical bone by micro-computed tomography.

PubMed

Cooper, D M L; Turinsky, A L; Sensen, C W; Hallgrímsson, B

2003-09-01

Cortical bone is perforated by an interconnected network of porous canals that facilitate the distribution of neurovascular structures throughout the cortex. This network is an integral component of cortical microstructure and, therefore, undergoes continual change throughout life as the cortex is remodeled. To date, the investigation of cortical microstructure, including the canal network, has largely been limited to the two-dimensional (2D) realm due to methodological hurdles. Thanks to continuing improvements in scan resolution, micro-computed tomography (muCT) is the first nondestructive imaging technology capable of resolving cortical canals. Like its application to trabecular bone, muCT provides an efficient means of quantifying aspects of 3D architecture of the canal network. Our aim here is to introduce the use of muCT for this application by providing examples, discussing some of the parameters that can be acquired, and relating these to research applications. Although several parameters developed for the analysis of trabecular microstructure are suitable for the analysis of cortical porosity, the algorithm used to estimate connectivity is not. We adapt existing algorithms based on skeletonization for this task. We believe that 3D analysis of the dimensions and architecture of the canal network will provide novel information relevant to many aspects of bone biology. For example, parameters related to the size, spacing, and volume of the canals may be particularly useful for investigation of the mechanical properties of bone. Alternatively, parameters describing the 3D architecture of the canal network, such as connectivity between the canals, may provide a means of evaluating cumulative remodeling related change. Copyright 2003 Wiley-Liss, Inc.

Compression and flexural strength of bone cement mixed with blood.

PubMed

Tan, J H; Koh, B Th; Ramruttun, A K; Wang, W

2016-08-01

To assess the compression and flexural strength of bone cement mixed with 0 ml, 1 ml, or 2 ml of blood. High viscosity polymethyl methacrylate (PMMA) loaded with or without gentamicin was used. Blood was collected from total knee arthroplasty patients. In the same operating room, one pack of cement each was mixed with 0 ml (control), 1 ml, or 2 ml of blood for 1 minute during the dough phase. The dough was extruded into cylindrical and rectangular moulds for 20 minutes of setting, and then cured in phosphate buffered saline at 37±1ºC for 7 days. The samples were visually inspected for fractures and areas of weakness, and then scanned using microcomputed tomography. 48 gentamicin-loaded and 59 non-gentamicin-loaded samples mixed with 0 ml (control), 1 ml, or 2 ml of blood were randomised for flexural and compression strength testing; each group had at least 6 samples. In samples loaded with or without gentamicin, the flexural and compressive strength was highest in controls, followed by samples mixed with 1 ml or 2 ml of blood. In samples mixed with 2 ml of blood, the flexural strength fell below the standard of 50 MPa. In samples mixed with 2 ml of blood and all gentamicin-loaded samples, the compressive strength fell below the standard of 70 MPa. Microcomputed tomography revealed areas of voids and pores indicating the presence of laminations and partitions within. The biomechanical strength of PMMA contaminated with blood may decrease. Precautions such as saline lavage, pack drying the bone, change of gloves, and prompt insertion of the implant should be taken to prevent blood from contaminating bone cement.

Attenuation Drift in the Micro-Computed Tomography System at LLNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooraghi, Alex A.; Brown, William; Seetho, Isaac

2016-01-12

The maximum allowable level of drift in the linear attenuation coefficients (μ) for a Lawrence Livermore National Laboratory (LLNL) micro-computed tomography (MCT) system was determined to be 0.1%. After ~100 scans were acquired during the period of November 2014 to March 2015, the drift in μ for a set of six reference materials reached or exceeded 0.1%. Two strategies have been identified to account for or correct the drift. First, normalizing the 160 kV and 100 kV μ data by the μ of water at the corresponding energy, in contrast to conducting normalization at the 160 kV energy only, significantlymore » compensates for measurement drift. Even after the modified normalization, μ of polytetrafluoroethylene (PTFE) increases linearly with scan number at an average rate of 0.00147% per scan. This is consistent with PTFE radiation damage documented in the literature. The second strategy suggested is the replacement of the PTFE reference with fluorinated ethylene propylene (FEP), which has the same effective atomic number (Ze) and electron density (ρe) as PTFE, but is 10 times more radiation resistant. This is important as effective atomic number and electron density are key parameters in analysis. The presence of a material with properties such as PTFE, when taken together with the remaining references, allows for a broad range of the (Ze, ρe) feature space to be used in analysis. While FEP is documented as 10 times more radiation resistant, testing will be necessary to assess how often, if necessary, FEP will need to be replaced. As radiation damage to references has been observed, it will be necessary to monitor all reference materials for radiation damage to ensure consistent x-ray characteristics of the references.« less

Cement Thickness of Inlay Restorations Made of Lithium Disilicate, Polymer-Infiltrated Ceramic and Nano-Ceramic CAD/CAM Materials Evaluated Using 3D X-Ray Micro-Computed Tomography.

PubMed

Uzgur, Recep; Ercan, Ertuğrul; Uzgur, Zeynep; Çolak, Hakan; Yalçın, Muhammet; Özcan, Mutlu

2016-08-12

To evaluate the marginal and internal cement thicknesses of inlay restorations made of various CAD/CAM materials using 3D X-ray micro-computed tomography (micro-CT) technique. Caries-free extracted mandibular molars (N = 30) with similar size were randomly assigned to three groups (N = 10 per group). Mesio-occlusal-distal (MOD) cavities were prepared, and inlay restorations were obtained by milling out CAD/CAM materials namely, (a) IPS: monolithic lithium disilicate (control), (b) VE: polymer-infiltrated ceramic, and (c) CS: nano-ceramic using a CAM unit. Marginal and internal cement thicknesses were measured using 3D micro-CT. Data were analyzed using 1-way ANOVA and Tukey's tests (alpha = 0.05). The mean marginal and internal cement thickness were not significant in all inlay materials (p > 0.05). Mean marginal cement thickness (μm) was the lowest for the IPS group (67.54 ± 10.16) followed by VE (84.09 ± 3.94) and CS (95.18 ± 10.58) (p > 0.05). The internal cement thickness (μm) was the lowest in the CS group (54.85 ± 6.94) followed by IPS (60.58 ± 9.22) and VE (77.53 ± 12.13) (p > 0.05). Marginal and internal cement thicknesses of MOD inlays made of monolithic lithium disilicate, polymer-infiltrated ceramic, and nano-ceramic CAD/CAM materials were similar and all less than 100 μm, which could be considered clinically acceptable. MOD inlays made of different CAD/CAM materials presented similar cement thickness, less than 100 μm. © 2016 by the American College of Prosthodontists.

Longitudinal in vivo microcomputed tomography of mouse lungs: No evidence for radiotoxicity

PubMed Central

Vande Velde, Greetje; De Langhe, Ellen; Poelmans, Jennifer; Bruyndonckx, Peter; d'Agostino, Emiliano; Verbeken, Erik; Bogaerts, Ria; Himmelreich, Uwe

2015-01-01

Before microcomputed tomography (micro-CT) can be exploited to its full potential for longitudinal monitoring of transgenic and experimental mouse models of lung diseases, radiotoxic side effects such as inflammation or fibrosis must be considered. We evaluated dose and potential radiotoxicity to the lungs for long-term respiratory-gated high-resolution micro-CT protocols. Free-breathing C57Bl/6 mice underwent four different retrospectively respiratory gated micro-CT imaging schedules of repeated scans during 5 or 12 wk, followed by ex vivo micro-CT and detailed histological and biochemical assessment of lung damage. Radiation exposure, dose, and absorbed dose were determined by ionization chamber, thermoluminescent dosimeter measurements and Monte Carlo calculations. Despite the relatively large radiation dose delivered per micro-CT acquisition, mice did not show any signs of radiation-induced lung damage or fibrosis when scanned weekly during 5 and up to 12 wk. Doubling the scanning frequency and once tripling the radiation dose as to mimic the instant repetition of a failed scan also stayed without detectable toxicity after 5 wk of scanning. Histological analyses confirmed the absence of radiotoxic damage to the lungs, thereby demonstrating that long-term monitoring of mouse lungs using high-resolution micro-CT is safe. This opens perspectives for longitudinal monitoring of (transgenic) mouse models of lung diseases and therapeutic response on an individual basis with high spatial and temporal resolution, without concerns for radiation toxicity that could potentially influence the readout of micro-CT-derived lung biomarkers. This work further supports the introduction of micro-CT for routine use in the preclinical pulmonary research field where postmortem histological approaches are still the gold standard. PMID:26024893

[Comparison of effectiveness and safety between Twisted File technique and ProTaper Universal rotary full sequence based on micro-computed tomography].

PubMed

Chen, Xiao-bo; Chen, Chen; Liang, Yu-hong

2016-02-18

To evaluate the efficacy and security of two type of rotary nickel titanium system (Twisted File and ProTaper Universal) for root canal preparation based on micro-computed tomography(micro-CT). Twenty extracted molars (including 62 canals) were divided into two experimental groups and were respectively instrumented using Twisted File rotary nickel titanium system (TF) and ProTaper Universal rotary nickel titanium system (PU) to #25/0.08 following recommended protocol. Time for root canal instrumentation (accumulation of time for every single file) was recorded. The 0-3 mm root surface from apex was observed under an optical stereomicroscope at 25 × magnification. The presence of crack line was noted. The root canals were scanned with micro-CT before and after root canal preparation. Three-dimensional shape images of canals were reconstructed, calculated and evaluated. The amount of canal central transportation of the two groups was calculated and compared. The shorter preparation time [(0.53 ± 0.14) min] was observed in TF group, while the preparation time of PU group was (2.06 ± 0.39) min (P<0.05). In mid-root level, TF group shaping resulted in less canal center transportation than PU group [(0.070 ± 0.056) mm vs. (0.097 ± 0.084) mm, P<0.05]. No instrument separation was observed in both the groups. Cracks were not found in both the groups either based in micro-CT images or observation under an optical stereomicroscope at 25 × magnification. Compared with ProTaper Universal, Twisted File took less time in root canal preparation and exhibited better shaping ability, and less canal transportation.

Comparison of alternative image reformatting techniques in micro-computed tomography and tooth clearing for detailed canal morphology.

PubMed

Lee, Ki-Wook; Kim, Yeun; Perinpanayagam, Hiran; Lee, Jong-Ki; Yoo, Yeon-Jee; Lim, Sang-Min; Chang, Seok Woo; Ha, Byung-Hyun; Zhu, Qiang; Kum, Kee-Yeon

2014-03-01

Micro-computed tomography (MCT) shows detailed root canal morphology that is not seen with traditional tooth clearing. However, alternative image reformatting techniques in MCT involving 2-dimensional (2D) minimum intensity projection (MinIP) and 3-dimensional (3D) volume-rendering reconstruction have not been directly compared with clearing. The aim was to compare alternative image reformatting techniques in MCT with tooth clearing on the mesiobuccal (MB) root of maxillary first molars. Eighteen maxillary first molar MB roots were scanned, and 2D MinIP and 3D volume-rendered images were reconstructed. Subsequently, the same MB roots were processed by traditional tooth clearing. Images from 2D, 3D, 2D + 3D, and clearing techniques were assessed by 4 endodontists to classify canal configuration and to identify fine anatomic structures such as accessory canals, intercanal communications, and loops. All image reformatting techniques in MCT showed detailed configurations and numerous fine structures, such that none were classified as simple type I or II canals; several were classified as types III and IV according to Weine classification or types IV, V, and VI according to Vertucci; and most were nonclassifiable because of their complexity. The clearing images showed less detail, few fine structures, and numerous type I canals. Classification of canal configuration was in 100% intraobserver agreement for all 18 roots visualized by any of the image reformatting techniques in MCT but for only 4 roots (22.2%) classified according to Weine and 6 (33.3%) classified according to Vertucci, when using the clearing technique. The combination of 2D MinIP and 3D volume-rendered images showed the most detailed canal morphology and fine anatomic structures. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Integration and evaluation of a needle-positioning robot with volumetric microcomputed tomography image guidance for small animal stereotactic interventions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waspe, Adam C.; McErlain, David D.; Pitelka, Vasek

Purpose: Preclinical research protocols often require insertion of needles to specific targets within small animal brains. To target biologically relevant locations in rodent brains more effectively, a robotic device has been developed that is capable of positioning a needle along oblique trajectories through a single burr hole in the skull under volumetric microcomputed tomography (micro-CT) guidance. Methods: An x-ray compatible stereotactic frame secures the head throughout the procedure using a bite bar, nose clamp, and ear bars. CT-to-robot registration enables structures identified in the image to be mapped to physical coordinates in the brain. Registration is accomplished by injecting amore » barium sulfate contrast agent as the robot withdraws the needle from predefined points in a phantom. Registration accuracy is affected by the robot-positioning error and is assessed by measuring the surface registration error for the fiducial and target needle tracks (FRE and TRE). This system was demonstrated in situ by injecting 200 {mu}m tungsten beads into rat brains along oblique trajectories through a single burr hole on the top of the skull under micro-CT image guidance. Postintervention micro-CT images of each skull were registered with preintervention high-field magnetic resonance images of the brain to infer the anatomical locations of the beads. Results: Registration using four fiducial needle tracks and one target track produced a FRE and a TRE of 96 and 210 {mu}m, respectively. Evaluation with tissue-mimicking gelatin phantoms showed that locations could be targeted with a mean error of 154{+-}113 {mu}m. Conclusions: The integration of a robotic needle-positioning device with volumetric micro-CT image guidance should increase the accuracy and reduce the invasiveness of stereotactic needle interventions in small animals.« less

Automated segmentation of synchrotron radiation micro-computed tomography biomedical images using Graph Cuts and neural networks

NASA Astrophysics Data System (ADS)

Alvarenga de Moura Meneses, Anderson; Giusti, Alessandro; de Almeida, André Pereira; Parreira Nogueira, Liebert; Braz, Delson; Cely Barroso, Regina; deAlmeida, Carlos Eduardo

2011-12-01

Synchrotron Radiation (SR) X-ray micro-Computed Tomography (μCT) enables magnified images to be used as a non-invasive and non-destructive technique with a high space resolution for the qualitative and quantitative analyses of biomedical samples. The research on applications of segmentation algorithms to SR-μCT is an open problem, due to the interesting and well-known characteristics of SR images for visualization, such as the high resolution and the phase contrast effect. In this article, we describe and assess the application of the Energy Minimization via Graph Cuts (EMvGC) algorithm for the segmentation of SR-μCT biomedical images acquired at the Synchrotron Radiation for MEdical Physics (SYRMEP) beam line at the Elettra Laboratory (Trieste, Italy). We also propose a method using EMvGC with Artificial Neural Networks (EMANNs) for correcting misclassifications due to intensity variation of phase contrast, which are important effects and sometimes indispensable in certain biomedical applications, although they impair the segmentation provided by conventional techniques. Results demonstrate considerable success in the segmentation of SR-μCT biomedical images, with average Dice Similarity Coefficient 99.88% for bony tissue in Wistar Rats rib samples (EMvGC), as well as 98.95% and 98.02% for scans of Rhodnius prolixus insect samples (Chagas's disease vector) with EMANNs, in relation to manual segmentation. The techniques EMvGC and EMANNs cope with the task of performing segmentation in images with the intensity variation due to phase contrast effects, presenting a superior performance in comparison to conventional segmentation techniques based on thresholding and linear/nonlinear image filtering, which is also discussed in the present article.

Micro-computed tomography pore-scale study of flow in porous media: Effect of voxel resolution

NASA Astrophysics Data System (ADS)

Shah, S. M.; Gray, F.; Crawshaw, J. P.; Boek, E. S.

2016-09-01

A fundamental understanding of flow in porous media at the pore-scale is necessary to be able to upscale average displacement processes from core to reservoir scale. The study of fluid flow in porous media at the pore-scale consists of two key procedures: Imaging - reconstruction of three-dimensional (3D) pore space images; and modelling such as with single and two-phase flow simulations with Lattice-Boltzmann (LB) or Pore-Network (PN) Modelling. Here we analyse pore-scale results to predict petrophysical properties such as porosity, single-phase permeability and multi-phase properties at different length scales. The fundamental issue is to understand the image resolution dependency of transport properties, in order to up-scale the flow physics from pore to core scale. In this work, we use a high resolution micro-computed tomography (micro-CT) scanner to image and reconstruct three dimensional pore-scale images of five sandstones (Bentheimer, Berea, Clashach, Doddington and Stainton) and five complex carbonates (Ketton, Estaillades, Middle Eastern sample 3, Middle Eastern sample 5 and Indiana Limestone 1) at four different voxel resolutions (4.4 μm, 6.2 μm, 8.3 μm and 10.2 μm), scanning the same physical field of view. Implementing three phase segmentation (macro-pore phase, intermediate phase and grain phase) on pore-scale images helps to understand the importance of connected macro-porosity in the fluid flow for the samples studied. We then compute the petrophysical properties for all the samples using PN and LB simulations in order to study the influence of voxel resolution on petrophysical properties. We then introduce a numerical coarsening scheme which is used to coarsen a high voxel resolution image (4.4 μm) to lower resolutions (6.2 μm, 8.3 μm and 10.2 μm) and study the impact of coarsening data on macroscopic and multi-phase properties. Numerical coarsening of high resolution data is found to be superior to using a lower resolution scan because it avoids the problem of partial volume effects and reduces the scaling effect by preserving the pore-space properties influencing the transport properties. This is evidently compared in this study by predicting several pore network properties such as number of pores and throats, average pore and throat radius and coordination number for both scan based analysis and numerical coarsened data.

Micro-computed tomography study of the internal anatomy of mesial root canals of mandibular molars.

PubMed

Villas-Bôas, Marcelo Haas; Bernardineli, Norberti; Cavenago, Bruno Cavalini; Marciano, Marina; Del Carpio-Perochena, Aldo; de Moraes, Ivaldo Gomes; Duarte, Marco H; Bramante, Clovis M; Ordinola-Zapata, Ronald

2011-12-01

The aim of this study was to determine the mesiodistal and buccolingual diameter, apical volume, and the presence of isthmuses at the apical level of mesial root canals of mandibular molars. Sixty extracted first and second mandibular molars were scanned by using a SkyScan 1076 micro-computed tomography system with a voxel size of 18 μm. The apical thirds of the samples were reconstructed to allow a perpendicular section of the apical third by using the multiplanar reconstruction tool of the OsiriX software. The mesiodistal and the buccolingual distances of root canals were measured between the 1- to 4-mm levels. The type of root canal isthmuses present at these levels was classified by using modified criteria of Hsu and Kim. The volume of the root canal anatomy between the 1- to 3-mm apical levels was obtained by using the CTAN-CTVOL software. The medians of the mesiodistal diameter at the 1-, 2-, 3-, and 4-mm levels in the mesiobuccal and mesiolingual canals were 0.22 and 0.23 mm, 0.27 and 0.27 mm, 0.30 and 0.30 mm, and 0.36 and 0.35 mm, respectively. The buccolingual lengths at the 1-, 2-, 3-, and 4-mm levels were 0.37-0.35 mm, 0.55-0.41 mm, 0.54-0.49 mm, and 0.54 and 0.60 mm, respectively. The presence of isthmuses was more prevalent at the 3- to 4-mm level. However, 27 cases presented complete or incomplete isthmuses at the 1-mm apical level. The mean of the volume of the apical third was 0.83 mm(3), with a minimum value of 0.02 and a maximum value of 2.4 mm(3). Mesial root canals of mandibular molars do not present a consistent pattern. A high variability of apical diameters exists. The presence of isthmuses at the apical third was not uncommon even at the 1-mm apical level. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Fully-automated, high-throughput micro-computed tomography analysis of body composition enables therapeutic efficacy monitoring in preclinical models.

PubMed

Wyatt, S K; Barck, K H; Kates, L; Zavala-Solorio, J; Ross, J; Kolumam, G; Sonoda, J; Carano, R A D

2015-11-01

The ability to non-invasively measure body composition in mouse models of obesity and obesity-related disorders is essential for elucidating mechanisms of metabolic regulation and monitoring the effects of novel treatments. These studies aimed to develop a fully automated, high-throughput micro-computed tomography (micro-CT)-based image analysis technique for longitudinal quantitation of adipose, non-adipose and lean tissue as well as bone and demonstrate utility for assessing the effects of two distinct treatments. An initial validation study was performed in diet-induced obesity (DIO) and control mice on a vivaCT 75 micro-CT system. Subsequently, four groups of DIO mice were imaged pre- and post-treatment with an experimental agonistic antibody specific for anti-fibroblast growth factor receptor 1 (anti-FGFR1, R1MAb1), control immunoglobulin G antibody, a known anorectic antiobesity drug (rimonabant, SR141716), or solvent control. The body composition analysis technique was then ported to a faster micro-CT system (CT120) to markedly increase throughput as well as to evaluate the use of micro-CT image intensity for hepatic lipid content in DIO and control mice. Ex vivo chemical analysis and colorimetric analysis of the liver triglycerides were performed as the standard metrics for correlation with body composition and hepatic lipid status, respectively. Micro-CT-based body composition measures correlate with ex vivo chemical analysis metrics and enable distinction between DIO and control mice. R1MAb1 and rimonabant have differing effects on body composition as assessed by micro-CT. High-throughput body composition imaging is possible using a modified CT120 system. Micro-CT also provides a non-invasive assessment of hepatic lipid content. This work describes, validates and demonstrates utility of a fully automated image analysis technique to quantify in vivo micro-CT-derived measures of adipose, non-adipose and lean tissue, as well as bone. These body composition metrics highly correlate with standard ex vivo chemical analysis and enable longitudinal evaluation of body composition and therapeutic efficacy monitoring.

The mechanical and biological studies of calcium phosphate cement-fibrin glue for bone reconstruction of rabbit femoral defects

PubMed Central

Dong, Jingjing; Cui, Geng; Bi, Long; Li, Jie; Lei, Wei

2013-01-01

In order to improve the mechanical and biological properties of calcium phosphate cement (CPC, nanometer-biomaterial) for bone reconstruction in the rabbit femoral defect model, fibrin glue (FG, the natural product, purified from the blood) was introduced at three different ratios. The CPC powder and the FG solution were mixed, respectively, at the powder/liquid (P/L) ratios (g/mL) of 1:1, 3:1, and 5:1 (g/mL), and pure CPC was used as a control. After being implanted into the femoral defect in rabbit, the healing process was evaluated by micro-computed tomography scan, biomechanical testing, and histological examination. By micro-computed tomography analysis, the P/L ratio of 1:1 (g/mL) group indicated the largest quantity of new bone formation at 4 weeks, 8 weeks, and 12 weeks after implantation, respectively. Bone volume per trabecular volume of the 1:1 group was highest in the four groups, which was 1.45% ± 0.42%, 7.35% ± 1.45%, and 29.10% ± 1.67% at 4 weeks, 8 weeks, and 12 weeks after the operation, respectively. In the biomechanical tests, the compressive strength and the elastic modulus of the three CPC–FG groups were much higher than those of the pure CPC group at the determined time point (P < 0.05). The histological evaluation also showed the best osseointegration in the 1:1 group at 4 weeks, 8 weeks, and 12 weeks after the operation, respectively. In the 1:1 group, the bone grew into the pore of the cement in the laminar arrangement and connected with the cement tightly at the 12th week after the operation. This present study indicated that the CPC–FG composite at the P/L ratio of 1:1 (g/mL) stimulated bone regeneration better than any other designed group, which suggested that CPC–FG at the P/L ratio of 1:1 has significant potential as the bioactive material for the treatment of bone defects. PMID:23576869

The microcomputer in cell and neurobiology research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mize, R.R.

1985-01-01

This book contains 21 chapters. They are divided into the following sections: The Microcomputer as a Research Tool, Microcomputer Uses in Light and Electron Microscopy, Microcomputer Uses in Morphometry, Serial Section Reconstruction, Microcomputer Uses in Imaging and Densitometry, and Microcomputer Uses in Electrophysiology.

A Longitudinal Study of Microcomputer Usage at the Community College Level in Kansas, Spring/94.

ERIC Educational Resources Information Center

Leite, Pedro T.

As part of a longitudinal project to inventory computer equipment and identify current instructional use of microcomputers in Kansas community colleges, surveys were sent to the 19 community colleges in Kansas in spring 1994. The surveys solicited data on student enrollment, which subject areas utilized microcomputers, types of hardware available,…

A microcomputer program for analysis of nucleic acid hybridization data

PubMed Central

Green, S.; Field, J.K.; Green, C.D.; Beynon, R.J.

1982-01-01

The study of nucleic acid hybridization is facilitated by computer mediated fitting of theoretical models to experimental data. This paper describes a non-linear curve fitting program, using the `Patternsearch' algorithm, written in BASIC for the Apple II microcomputer. The advantages and disadvantages of using a microcomputer for local data processing are discussed. Images PMID:7071017

Multi-modal porous microstructure for high temperature fuel cell application

NASA Astrophysics Data System (ADS)

Wejrzanowski, T.; Haj Ibrahim, S.; Cwieka, K.; Loeffler, M.; Milewski, J.; Zschech, E.; Lee, C.-G.

2018-01-01

In this study, the effect of microstructure of porous nickel electrode on the performance of high temperature fuel cell is investigated and presented based on a molten carbonate fuel cell (MCFC) cathode. The cathode materials are fabricated from slurry consisting of nickel powder and polymeric binder/solvent mixture, using the tape casting method. The final pore structure is shaped through modifying the slurry composition - with or without the addition of porogen(s). The manufactured materials are extensively characterized by various techniques involving: micro-computed tomography (micro-XCT), scanning electron microscopy (SEM), mercury porosimetry, BET and Archimedes method. Tomographic images are also analyzed and quantified to reveal the evolution of pore space due to nickel in situ oxidation to NiO, and infiltration by the electrolyte. Single-cell performance tests are carried out under MCFC operation conditions to estimate the performance of the manufactured materials. It is found that the multi-modal microstructure of MCFC cathode results in a significant enhancement of the power density generated by the reference cell. To give greater insight into the understanding of the effect of microstructure on the properties of the cathode, a model based on 3D tomography image transformation is proposed.

Application of nondestructive testing methods to study the damage zone underneath impact craters of MEMIN laboratory experiments

NASA Astrophysics Data System (ADS)

Moser, Dorothee; Poelchau, Michael H.; Stark, Florian; Grosse, Christian

2013-01-01

Within the framework of the Multidisciplinary Experimental and Modeling Impact Research Network (MEMIN) research group, the damage zones underneath two experimentally produced impact craters in sandstone targets were investigated using several nondestructive testing (NDT) methods. The 20 × 20 × 20 cm sandstones were impacted by steel projectiles with a radius of 1.25 mm at approximately 5 km s-1, resulting in craters with approximately 6 cm diameter and approximately 1 cm depth. Ultrasound (US) tomography and vibrational analysis were applied before and after the impact experiments to characterize the damage zone, and micro-computer tomography (μ-CT) measurements were performed to visualize subsurface fractures. The newly obtained experimental data can help to quantify the extent of the damage zone, which extends to about 8 cm depth in the target. The impacted sandstone shows a local p-wave reduction of 18% below the crater floor, and a general reduction in elastic moduli by between approximately 9 and approximately 18%, depending on the type of elastic modulus. The results contribute to a better empirical and theoretical understanding of hypervelocity events and simulations of cratering processes.

Cortical bone thickening in Type A posterior atlas arch defects: experimental report.

PubMed

Sanchis-Gimeno, Juan A; Llido, Susanna; Guede, David; Martinez-Soriano, Francisco; Ramon Caeiro, Jose; Blanco-Perez, Esther

2017-03-01

To date, no information about the cortical bone microstructural properties in atlas vertebrae with posterior arch defects has been reported. To test if there is an increased cortical bone thickening in atlases with Type A posterior atlas arch defects in an experimental model. Micro-computed tomography (CT) study on cadaveric atlas vertebrae. We analyzed the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry vertebrae with a Type A atlas arch defect and normal control vertebrae. The micro-CT study revealed significant differences in cortical bone thickness (p=.005), cortical volume (p=.003), and medullary volume (p=.009) values between the normal and the Type A vertebrae. Type A congenital atlas arch defects present a cortical bone thickening that may play a protective role against atlas fractures. Copyright © 2016 Elsevier Inc. All rights reserved.

Functional trade-off between strength and thermal capacity of dermal armor: Insights from girdled lizards.

PubMed

Broeckhoven, Chris; du Plessis, Anton; Hui, Cang

2017-10-01

The presence of dermal armor is often unambiguously considered the result of an evolutionary predator-prey arms-race. Recent studies focusing predominantly on osteoderms - mineralized elements embedded in the dermis layer of various extant and extinct vertebrates - have instead proposed that dermal armor might exhibit additional functionalities besides protection. Multiple divergent functionalities could impose conflicting demands on a phenotype, yet, functional trade-offs in dermal armor have rarely been investigated. Here, we use high-resolution micro-computed tomography and voxel-based simulations to test for a trade-off between the strength and thermal capacity of osteoderms using two armored cordylid lizards as model organisms. We demonstrate that high vascularization, associated with improved thermal capacity might limit the strength of osteoderms. These results call for a holistic, cautionary future approach to studies investigating dermal armor, especially those aiming to inspire artificial protective materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

A method for evaluating the murine pulmonary vasculature using micro-computed tomography.

PubMed

Phillips, Michael R; Moore, Scott M; Shah, Mansi; Lee, Clara; Lee, Yueh Z; Faber, James E; McLean, Sean E

2017-01-01

Significant mortality and morbidity are associated with alterations in the pulmonary vasculature. While techniques have been described for quantitative morphometry of whole-lung arterial trees in larger animals, no methods have been described in mice. We report a method for the quantitative assessment of murine pulmonary arterial vasculature using high-resolution computed tomography scanning. Mice were harvested at 2 weeks, 4 weeks, and 3 months of age. The pulmonary artery vascular tree was pressure perfused to maximal dilation with a radio-opaque casting material with viscosity and pressure set to prevent capillary transit and venous filling. The lungs were fixed and scanned on a specimen computed tomography scanner at 8-μm resolution, and the vessels were segmented. Vessels were grouped into categories based on lumen diameter and branch generation. Robust high-resolution segmentation was achieved, permitting detailed quantitation of pulmonary vascular morphometrics. As expected, postnatal lung development was associated with progressive increase in small-vessel number and arterial branching complexity. These methods for quantitative analysis of the pulmonary vasculature in postnatal and adult mice provide a useful tool for the evaluation of mouse models of disease that affect the pulmonary vasculature. Copyright © 2016 Elsevier Inc. All rights reserved.

Microcomputers in Transit: A Needs Assessment and Implementation Handbook. Final Report.

ERIC Educational Resources Information Center

Wyatt, Eve; Smerk, George

This handbook describes a practical step-by-step process for introducing microcomputers to small- and medium-sized transit operating agencies. The introductory chapter deals with the objective of buying a microcomputer system, the characteristics of microcomputers, microcomputer software, microcomputer system components, and issues faced in…

[Research progress of polyethylene inserts wear measurement and evaluation in total knee arthroplasty].

PubMed

Zhao, Feng; Wang, Chuan; Fan, Yubo

2015-01-01

Wear of polyethylene (PE) tibial inserts is a significant cause of implant failure of total knee arthroplasty (TKA). PE inserts wear measurement and evaluation is the key in TKA researches. There are many methods to measure insert wear. Qualitative methods such as observation are used to determine the wear and its type. Quantitative methods such as gravimetric analysis, coordinate measuring machines (CMM) and micro-computed tomography (micro-CT) are used to measure the mass, volume and geometry of wear. In this paper, the principle, characteristics and research progress of main insert wear evaluation method were introduced and the problems and disadvantages were analyzed.

NDE of Fiber Reinforced Foam Composite Structures for Future Aerospace Vehicles

NASA Technical Reports Server (NTRS)

Walker, james; Roth, Don; Hopkins, Dale

2010-01-01

This slide presentation reviews the complexities of non-destructive evaluation (NDE) of fiber reinforced foam composite structures to be used for aerospace vehicles in the future.Various views of fiber reinforced foam materials are shown and described. Conventional methods of NDE for composites are reviewed such as Micro-computed X-Ray Tomography, Thermography, Shearography, and Phased Array Ultrasonics (PAUT). These meth0ods appear to work well on the face sheet and face sheet ot core bond, they do not provide adequate coverage for the webs. There is a need for additional methods that will examine the webs and web to foam core bond.

Materials Characterization of Additively Manufactured Components for Rocket Propulsion

NASA Technical Reports Server (NTRS)

Carter, Robert; Draper, Susan; Locci, Ivan; Lerch, Bradley; Ellis, David; Senick, Paul; Meyer, Michael; Free, James; Cooper, Ken; Jones, Zachary

2015-01-01

To advance Additive Manufacturing (AM) technologies for production of rocket propulsion components the NASA Glenn Research Center (GRC) is applying state of the art characterization techniques to interrogate microstructure and mechanical properties of AM materials and components at various steps in their processing. The materials being investigated for upper stage rocket engines include titanium, copper, and nickel alloys. Additive manufacturing processes include laser powder bed, electron beam powder bed, and electron beam wire fed processes. Various post build thermal treatments, including Hot Isostatic Pressure (HIP), have been studied to understand their influence on microstructure, mechanical properties, and build density. Micro-computed tomography, electron microscopy, and mechanical testing in relevant temperature environments has been performed to develop relationships between build quality, microstructure, and mechanical performance at temperature. A summary of GRC's Additive Manufacturing roles and experimental findings will be presented.

Material Characterization of Additively Manufactured Components for Rocket Propulsion

NASA Technical Reports Server (NTRS)

Carter, Robert; Draper, Susan; Locci, Ivan; Lerch, Bradley; Ellis, David; Senick, Paul; Meyer, Michael; Free, James; Cooper, Ken; Jones, Zachary

2015-01-01

To advance Additive Manufacturing (AM) technologies for production of rocket propulsion components the NASA Glenn Research Center (GRC) is applying state of the art characterization techniques to interrogate microstructure and mechanical properties of AM materials and components at various steps in their processing. The materials being investigated for upper stage rocket engines include titanium, copper, and nickel alloys. Additive manufacturing processes include laser powder bed, electron beam powder bed, and electron beam wire fed processes. Various post build thermal treatments, including Hot Isostatic Pressure (HIP), have been studied to understand their influence on microstructure, mechanical properties, and build density. Micro-computed tomography, electron microscopy, and mechanical testing in relevant temperature environments has been performed to develop relationships between build quality, microstructure, and mechanical performance at temperature. A summary of GRCs Additive Manufacturing roles and experimental findings will be presented.

Fast frame rate rodent cardiac x-ray imaging using scintillator lens coupled to CMOS camera

NASA Astrophysics Data System (ADS)

Swathi Lakshmi, B.; Sai Varsha, M. K. N.; Kumar, N. Ashwin; Dixit, Madhulika; Krishnamurthi, Ganapathy

2017-03-01

Micro-Computed Tomography (MCT) systems for small animal imaging plays a critical role for monitoring disease progression and therapy evaluation. In this work, an in-house built micro-CT system equipped with a X-ray scintillator lens coupled to a commercial CMOS camera was used to test the feasibility of its application to Digital Subtraction Angiography (DSA). Literature has reported such studies being done with clinical X-ray tubes that can be pulsed rapidly or with rotating gantry systems, thus increasing the cost and infrastructural requirements.The feasibility of DSA was evaluated by injected Iodinated contrast agent (ICA) through the tail vein of a mouse. Projection images of the heart were acquired pre and post contrast using the high frame rate X-ray detector and processing done to visualize transit of ICA through the heart.

Dynamic tensile fracture of mortar at ultra-high strain-rates

NASA Astrophysics Data System (ADS)

Erzar, B.; Buzaud, E.; Chanal, P.-Y.

2013-12-01

During the lifetime of a structure, concrete and mortar may be exposed to highly dynamic loadings, such as impact or explosion. The dynamic fracture at high loading rates needs to be well understood to allow an accurate modeling of this kind of event. In this work, a pulsed-power generator has been employed to conduct spalling tests on mortar samples at strain-rates ranging from 2 × 104 to 4 × 104 s-1. The ramp loading allowed identifying the strain-rate anytime during the test. A power law has been proposed to fit properly the rate-sensitivity of tensile strength of this cementitious material over a wide range of strain-rate. Moreover, a specimen has been recovered damaged but unbroken. Micro-computed tomography has been employed to study the characteristics of the damage pattern provoked by the dynamic tensile loading.

Piaget and Microcomputer Learning Environments.

ERIC Educational Resources Information Center

Hofmann, Rich

1986-01-01

Four studies are offered from a Piagetian perspective on providing children with an optimal microcomputer environment. Guidelines stress the importance of flexibility, and a hierarchical software environment. (CL)

Micro computed tomography evaluation of the Self-adjusting file and ProTaper Universal system on curved mandibular molars.

PubMed

Serefoglu, Burcu; Piskin, Beyser

2017-09-26

The aim of this investigation was to compare the cleaning and shaping efficiency of Self-adjusting file and Protaper, and to assess the correlation between root canal curvature and working time in mandibular molars using micro-computed tomography. Twenty extracted mandibular molars instrumented with Protaper and Self-adjusting file and the total working time was measured in mesial canals. The changes in canal volume, surface area and structure model index, transportation, uninstrumented area and the correlation between working-time and the curvature were analyzed. Although no statistically significant difference was observed between two systems in distal canals (p>0.05), a significantly higher amount of removed dentin volume and lower uninstrumented area were provided by Protaper in mesial canals (p<0.0001). A correlation between working-time and the canal-curvature was also observed in mesial canals for both groups (SAFr 2 =0.792, p<0.0004, PTUr 2 =0.9098, p<0.0001).

Quantification of eggshell microstructure using X-ray micro computed tomography

PubMed Central

Riley, A.; Sturrock, C. J.; Mooney, S. J.

2014-01-01

1. X-ray microcomputed tomography can be used to produce rapid, fully analysable, three-dimensional images of biological and other materials without the need for complex or tedious sample preparation and sectioning. We describe the use of this technique to visualise and analyse the microstructure of fragments of shell taken from three regions of chicken eggs (sharp pole, blunt pole and equatorial region). 2. Two- and three-dimensional images and data were obtained at a resolution of 1.5 microns. The images were analysed to provide measurements of shell thickness, the spacial density of mammillary bodies, the frequency, shape, volume and effective diameter of individual pore spaces, and the intrinsic sponginess (proportion of non-X-ray dense material formed by vesicles) of the shell matrix. Measurements of these parameters were comparable with those derived by traditional methods and reported in the literature. 3. The advantages of using this technology for the quantification of eggshell microstructural parameters and its potential application for commercial, research and other purposes are discussed. PMID:24875292

The mystery of a missing bone: revealing the orbitosphenoid in basal Epicynodontia (Cynodontia, Therapsida) through computed tomography

NASA Astrophysics Data System (ADS)

Benoit, Julien; Jasinoski, Sandra C.; Fernandez, Vincent; Abdala, Fernando

2017-08-01

The basal non-mammaliaform cynodonts from the late Permian (Lopingian) and Early Triassic are a major source of information for the understanding of the evolutionary origin of mammals. Detailed knowledge of their anatomy is critical for understanding the phylogenetic transition toward mammalness and the paleobiological reconstruction of mammalian precursors. Using micro-computed tomography (μCT), we describe the internal morphology of the interorbital region that includes the rarely fossilized orbitosphenoid elements in four basal cynodonts. These paired bones, which are positioned relatively dorsally in the skull, contribute to the wall of the anterior part of the braincase and form the floor for the olfactory lobes. Unlike procynosuchids and the more basal therapsids in which the orbitosphenoids are well developed, dense, and bear a ventral keel, the basal epicynodonts Cynosaurus, Galesaurus, and Thrinaxodon display cancellous, reduced, and loosely articulated orbitosphenoids, a condition shared with many eucynodonts. The hemi-cylindrical orbitosphenoid from which the mammalian condition is derived re-evolved convergently in traversodontid and some probainognathian cynodonts.

Gold nanoparticle imaging and radiotherapy of brain tumors in mice

PubMed Central

Hainfeld, James F; Smilowitz, Henry M; O'Connor, Michael J; Dilmanian, Farrokh Avraham; Slatkin, Daniel N

2013-01-01

Aim To test intravenously injected gold nanoparticles for x-ray imaging and radiotherapy enhancement of large, imminently lethal, intracerebral malignant gliomas. Materials & methods Gold nanoparticles approximately 11 nm in size were injected intravenously and brains imaged using microcomputed tomography. A total of 15 h after an intravenous dose of 4 g Au/kg was administered, brains were irradiated with 30 Gy 100 kVp x-rays. Results Gold uptake gave a 19:1 tumor-to-normal brain ratio with 1.5% w/w gold in tumor, calculated to increase local radiation dose by approximately 300%. Mice receiving gold and radiation (30 Gy) demonstrated 50% long term (>1 year) tumor-free survival, whereas all mice receiving radiation only died. Conclusion Intravenously injected gold nanoparticles cross the blood–tumor barrier, but are largely blocked by the normal blood–brain barrier, enabling high-resolution computed tomography tumor imaging. Gold radiation enhancement significantly improved long-term survival compared with radiotherapy alone. This approach holds promise to improve therapy of human brain tumors and other cancers. PMID:23265347

The effect of a manual instrumentation technique on five types of premolar root canal geometry assessed by microcomputed tomography and three-dimensional reconstruction

PubMed Central

2011-01-01

Background Together with diagnosis and treatment planning, a good knowledge of the root canal system and its frequent variations is a necessity for successful root canal therapy. The selection of instrumentation techniques for variants in internal anatomy of teeth has significant effects on the shaping ability and cleaning effectiveness. The aim of this study was to reveal the differences made by including variations in the internal anatomy of premolars into the study protocol for investigation of a single instrumentation technique (hand ProTaper instruments) assessed by microcomputed tomography and three-dimensional reconstruction. Methods Five single-root premolars, whose root canal systems were classified into one of five types, were scanned with micro-CT before and after preparation with a hand ProTaper instrument. Instrumentation characteristics were measured quantitatively in 3-D using a customized application framework based on MeVisLab. Numeric values were obtained for canal surface area, volume, volume changes, percentage of untouched surface, dentin wall thickness, and the thickness of dentin removed. Preparation errors were also evaluated using a color-coded reconstruction. Results Canal volumes and surface areas were increased after instrumentation. Prepared canals of all five types were straightened, with transportation toward the inner aspects of S-shaped or multiple curves. However, a ledge was formed at the apical third curve of the type II canal system and a wide range in the percentage of unchanged canal surfaces (27.4-83.0%) was recorded. The dentin walls were more than 0.3 mm thick except in a 1 mm zone from the apical surface and the hazardous area of the type II canal system after preparation with an F3 instrument. Conclusions The 3-D color-coded images showed different morphological changes in the five types of root canal systems shaped with the same hand instrumentation technique. Premolars are among the most complex teeth for root canal treatment and instrumentation techniques for the root canal systems of premolars should be selected individually depending on the 3-D canal configuration of each tooth. Further study is needed to demonstrate the differences made by including variations in the internal anatomy of teeth into the study protocol of clinical RCT for identifying the best preparation technique. PMID:21676233

Biomedical implications of dental-ceramic defects investigated by numerical simulation, radiographic, microcomputer tomography, and time-domain optical coherence tomography

NASA Astrophysics Data System (ADS)

Sinescu, Cosmin; Negrutiu, Meda Lavinia; Ionita, Ciprian; Marsavina, Liviu; Negru, Radu; Topala, Florin; Petrescu, Emanuela; Rominu, Roxana; Fabriky, Mihai; Bradu, Adrian; Rominu, Mihai; Podoleanu, Adrian Gh.

2011-10-01

Imagistic investigation of the metal-ceramic crowns and fixed partial prostheses represent a very important issue in nowadays dentistry. At this time, in dental office, it is difficult or even impossible to evaluate a metal ceramic crown or bridge before setting it in the oral cavity. The possibilities of ceramic fractures are due to small fracture lines or material defects inside the esthetic layers. Material and methods: In this study 25 metal ceramic crowns and fixed partial prostheses were investigated by radiographic method (Rx), micro computer tomography (MicroCT) and optical coherence tomography (OCT) working in Time Domain, at 1300 nm. The OCT system contains two interferometers and one scanner. For each incident analysis a stuck made of 100 slices was obtain. These slices were used in order to obtain a 3D model of the ceramic interface. After detecting the presence and the positions of the ceramic defects the numerical simulation method was used to estimate the biomechanical effect of the masticatory forces on fractures propagations in ceramic materials. Results: For all the dental ceramic defects numerical simulation analysis was performed. The simulation of crack propagation shows that the crack could initiate from the upper, lower or both parts of the defect and propagates through the ceramic material where tensile stress field is present. RX and MicroCT are very powerful instruments that provide a good characterization of the dental construct. It is important to observe the reflections due to the metal infrastructure that could affect the evaluation of the metal ceramic crowns and bridges. The OCT investigations could complete the imagistic evaluation of the dental construct by offering important information when it is need it.

A research strategy for the dynamic study of students' concepts and problem solving strategies using science software

NASA Astrophysics Data System (ADS)

Krajcik, Joseph S.; Simmons, Patricia E.; Lunetta, Vincent N.

Microcomputers and appropriate software have the potential to help students learn. They can also serve as appropriate media for investigating how students learn. In this article we describe a research strategy examining learning and behavior when students interacted with microcomputers and software. Results from two preliminary studies illustrate the strategy.A major feature of the strategy included recording students interacting with microcomputer software interfaced with a VCR. The VCR recorded the video output from a microcomputer and students' verbal commentary via microphone input. This technique allowed students' comments about their observations, perceptions, predictions, explanations, and decisions to be recorded simultaneously with their computer input and the display on the microcomputer monitor.The research strategy described can provide important information about cognitive and affective behaviors of students engaged in using instructional software. Research studies utilizing this strategy can enhance our understanding of how students develop and employ important concepts and scientific relationships, how students develop problem-solving skills and solve problems, and how they interact with instructional software. Results of such studies have important implications for teaching and for the design of instructional software.

Permeability study of cancellous bone and its idealised structures.

PubMed

Syahrom, Ardiyansyah; Abdul Kadir, Mohammed Rafiq; Harun, Muhamad Nor; Öchsner, Andreas

2015-01-01

Artificial bone is a suitable alternative to autografts and allografts, however their use is still limited. Though there were numerous reports on their structural properties, permeability studies of artificial bones were comparably scarce. This study focused on the development of idealised, structured models of artificial cancellous bone and compared their permeability values with bone surface area and porosity. Cancellous bones from fresh bovine femur were extracted and cleaned following an established protocol. The samples were scanned using micro-computed tomography (μCT) and three-dimensional models of the cancellous bones were reconstructed for morphology study. Seven idealised and structured cancellous bone models were then developed and fabricated via rapid prototyping technique. A test-rig was developed and permeability tests were performed on the artificial and real cancellous bones. The results showed a linear correlation between the permeability and the porosity as well as the bone surface area. The plate-like idealised structure showed a similar value of permeability to the real cancellous bones. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

3-Dimensional quantitative detection of nanoparticle content in biological tissue samples after local cancer treatment

NASA Astrophysics Data System (ADS)

Rahn, Helene; Alexiou, Christoph; Trahms, Lutz; Odenbach, Stefan

2014-06-01

X-ray computed tomography is nowadays used for a wide range of applications in medicine, science and technology. X-ray microcomputed tomography (XμCT) follows the same principles used for conventional medical CT scanners, but improves the spatial resolution to a few micrometers. We present an example of an application of X-ray microtomography, a study of 3-dimensional biodistribution, as along with the quantification of nanoparticle content in tumoral tissue after minimally invasive cancer therapy. One of these minimal invasive cancer treatments is magnetic drug targeting, where the magnetic nanoparticles are used as controllable drug carriers. The quantification is based on a calibration of the XμCT-equipment. The developed calibration procedure of the X-ray-μCT-equipment is based on a phantom system which allows the discrimination between the various gray values of the data set. These phantoms consist of a biological tissue substitute and magnetic nanoparticles. The phantoms have been studied with XμCT and have been examined magnetically. The obtained gray values and nanoparticle concentration lead to a calibration curve. This curve can be applied to tomographic data sets. Accordingly, this calibration enables a voxel-wise assignment of gray values in the digital tomographic data set to nanoparticle content. Thus, the calibration procedure enables a 3-dimensional study of nanoparticle distribution as well as concentration.

Diagnostic Accuracy of Periapical Radiography and Cone-beam Computed Tomography in Identifying Root Canal Configuration of Human Premolars.

PubMed

Sousa, Thiago Oliveira; Haiter-Neto, Francisco; Nascimento, Eduarda Helena Leandro; Peroni, Leonardo Vieira; Freitas, Deborah Queiroz; Hassan, Bassam

2017-07-01

The aim of this study was to assess the diagnostic accuracy of periapical radiography (PR) and cone-beam computed tomographic (CBCT) imaging in the detection of the root canal configuration (RCC) of human premolars. PR and CBCT imaging of 114 extracted human premolars were evaluated by 2 oral radiologists. RCC was recorded according to Vertucci's classification. Micro-computed tomographic imaging served as the gold standard to determine RCC. Accuracy, sensitivity, specificity, and predictive values were calculated. The Friedman test compared both PR and CBCT imaging with the gold standard. CBCT imaging showed higher values for all diagnostic tests compared with PR. Accuracy was 0.55 and 0.89 for PR and CBCT imaging, respectively. There was no difference between CBCT imaging and the gold standard, whereas PR differed from both CBCT and micro-computed tomographic imaging (P < .0001). CBCT imaging was more accurate than PR for evaluating different types of RCC individually. Canal configuration types III, VII, and "other" were poorly identified on CBCT imaging with a detection accuracy of 50%, 0%, and 43%, respectively. With PR, all canal configurations except type I were poorly visible. PR presented low performance in the detection of RCC in premolars, whereas CBCT imaging showed no difference compared with the gold standard. Canals with complex configurations were less identifiable using both imaging methods, especially PR. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A micro-computed tomographic evaluation of dentinal microcrack alterations during root canal preparation using single-file Ni-Ti systems.

PubMed

Li, Mei-Lin; Liao, Wei-Li; Cai, Hua-Xiong

2018-01-01

The aim of the present study was to evaluate the length of dentinal microcracks observed prior to and following root canal preparation with different single-file nickel-titanium (Ni-Ti) systems using micro-computed tomography (micro-CT) analysis. A total of 80 mesial roots of mandibular first molars presenting with type II Vertucci canal configurations were scanned at an isotropic resolution of 7.4 µm. The samples were randomly assigned into four groups (n=20 per group) according to the system used for root canal preparation, including the WaveOne (WO), OneShape (OS), Reciproc (RE) and control groups. A second micro-CT scan was conducted after the root canals were prepared with size 25 instruments. Pre- and postoperative cross-section images of the roots (n=237,760) were then screened to identify the lengths of the microcracks. The results indicated that the microcrack lengths were notably increased following root canal preparation (P<0.05). The alterations in microcrack length in the OS group were more significant compared with those in the WO, RE and control groups (P<0.05). In conclusion, the formation and development of dentinal microcracks may be associated with the movement caused by preparation rather than the taper of the files. Among the single-file Ni-Ti systems, WO and RE were not observed to cause notable microcracks, while the OS system resulted in evident microcracks.

Microcomputers in the Introductory Laboratory.

ERIC Educational Resources Information Center

Bare, John K.

1982-01-01

A microcomputer was used successfully to replicate Sternberg's 1966 study of retrieval from short-term memory and Sperling's 1960 study on sensory or iconic memory. Computers with a capacity for measuring reaction time are useful in the laboratory for introductory psychology courses. (SR)

Use of microcomputers in health and social service applications in developing nations.

PubMed

Bertrand, W E

1987-01-01

The microcomputer is creating something of a revolution in many developing nations where historically there has been a lack of access to computer power at all levels of the health sector. For the first time, practitioners and researchers, often trained in computer techniques for developing countries, have access through microcomputers to data and information manipulation in their local workplace. While the history of microcomputers in such settings is short, this article presents early evidence from several countries which indicates the usefulness of various applications. The majority of the applications reported in the literature from clinical and research laboratories is made up of national data base systems and special studies of morbidity and mortality. Secondary applications, including assistance in biographical searches and word and graphics processing, are also reviewed in this article. A summary of the most utilized microcomputer hardware configurations completes the review.

Application of in vivo micro-computed tomography in the temporal characterisation of subchondral bone architecture in a rat model of low-dose monosodium iodoacetate-induced osteoarthritis

PubMed Central

2011-01-01

Introduction Osteoarthritis (OA) is a complex, multifactorial joint disease affecting both the cartilage and the subchondral bone. Animal models of OA aid in the understanding of the pathogenesis of OA and testing suitable drugs for OA treatment. In this study we characterized the temporal changes in the tibial subchondral bone architecture in a rat model of low-dose monosodium iodoacetate (MIA)-induced OA using in vivo micro-computed tomography (CT). Methods Male Wistar rats received a single intra-articular injection of low-dose MIA (0.2 mg) in the right knee joint and sterile saline in the left knee joint. The animals were scanned in vivo by micro-CT at two, six, and ten weeks post-injection, analogous to early, intermediate, and advanced stages of OA, to assess architectural changes in the tibial subchondral bone. The articular cartilage changes in the tibiae were assessed macroscopically and histologically at ten weeks post-injection. Results Interestingly, tibiae of the MIA-injected knees showed significant bone loss at two weeks, followed by increased trabecular thickness and separation at six and ten weeks. The trabecular number was decreased at all time points compared to control tibiae. The tibial subchondral plate thickness of the MIA-injected knee was increased at two and six weeks and the plate porosity was increased at all time points compared to control. At ten weeks, histology revealed loss of proteoglycans, chondrocyte necrosis, chondrocyte clusters, cartilage fibrillation, and delamination in the MIA-injected tibiae, whereas the control tibiae showed no changes. Micro-CT images and histology showed the presence of subchondral bone sclerosis, cysts, and osteophytes. Conclusions These findings demonstrate that the low-dose MIA rat model closely mimics the pathological features of progressive human OA. The low-dose MIA rat model is therefore suitable to study the effect of therapeutic drugs on cartilage and bone in a non-trauma model of OA. In vivo micro-CT is a non-destructive imaging technique that can track structural changes in the tibial subchondral bone in this animal model, and could also be used to track changes in bone in preclinical drug intervention studies for OA treatments. PMID:22185204

Evaluation of Anterior Vertebral Interbody Fusion Using Osteogenic Mesenchymal Stem Cells Transplanted in Collagen Sponge.

PubMed

Yang, Wencheng; Dong, Youhai; Hong, Yang; Guang, Qian; Chen, Xujun

2016-05-01

The study used a rabbit model to achieve anterior vertebral interbody fusion using osteogenic mesenchymal stem cells (OMSCs) transplanted in collagen sponge. We investigated the effectiveness of graft material for anterior vertebral interbody fusion using a rabbit model by examining the OMSCs transplanted in collagen sponge. Anterior vertebral interbody fusion is commonly performed. Although autogenous bone graft remains the gold-standard fusion material, it requires a separate surgical procedure and is associated with significant short-term and long-term morbidity. Recently, mesenchymal stem cells from bone marrow have been studied in various fields, including posterolateral spinal fusion. Thus, we hypothesized that cultured OMSCs transplanted in porous collagen sponge could be used successfully even in anterior vertebral interbody fusion. Forty mature male White Zealand rabbits (weight, 3.5-4.5 kg) were randomly allocated to receive one of the following graft materials: porous collagen sponge plus cultured OMSCs (group I); porous collagen sponge alone (group II); autogenous bone graft (group III); and nothing (group IV). All animals underwent anterior vertebral interbody fusion at the L4/L5 level. The lumbar spine was harvested en bloc, and the new bone formation and spinal fusion was evaluated using radiographic analysis, microcomputed tomography, manual palpation test, and histologic examination at 8 and 12 weeks after surgery. New bone formation and bony fusion was evident as early as 8 weeks in groups I and III. And there was no statistically significant difference between 8 and 12 weeks. At both time points, by microcomputed tomography and histologic analysis, new bone formation was observed in both groups I and III, fibrous tissue was observed and there was no new bone in both groups II and IV; by manual palpation test, bony fusion was observed in 40% (4/10) of rabbits in group I, 70% (7/10) of rabbits in group III, and 0% (0/10) of rabbits in both groups II and IV. These findings suggest that mesenchymal stem cells that have been cultured with osteogenic differentiation medium and loaded with collagen sponge could induce bone formation and anterior vertebral interbody fusion. And the rabbit model we developed will be useful in evaluating the effects of graft materials for anterior vertebral interbody fusion. Further study is needed to determine the most appropriate carrier for OMSCs and the feasibility in the clinical setting.

A microcomputed tomography evaluation of the marginal fit of cobalt-chromium alloy copings fabricated by new manufacturing techniques and alloy systems.

PubMed

Kim, Eun-Ha; Lee, Du-Hyeong; Kwon, Sung-Min; Kwon, Tae-Yub

2017-03-01

Although new digital manufacturing techniques are attracting interest in dentistry, few studies have comprehensively investigated the marginal fit of fixed dental prostheses fabricated with such techniques. The purpose of this in vitro microcomputed tomography (μCT) study was to evaluate the marginal fit of cobalt-chromium (Co-Cr) alloy copings fabricated by casting and 3 different computer-aided design and computer-aided manufacturing (CAD-CAM)-based processing techniques and alloy systems. Single Co-Cr metal crowns were fabricated using 4 different manufacturing techniques: casting (control), milling, selective laser melting, and milling/sintering. Two different commercial alloy systems were used for each fabrication technique (a total of 8 groups; n=10 for each group). The marginal discrepancy and absolute marginal discrepancy of the crowns were determined with μCT. For each specimen, the values were determined from 4 different regions (sagittal buccal, sagittal lingual, coronal mesial, and coronal distal) by using imaging software and recorded as the average of the 4 readings. For each parameter, the results were statistically compared with 2-way analysis of variance and appropriate post hoc analysis (using Tukey or Student t test) (α=.05). The milling and selective laser melting groups showed significantly larger marginal discrepancies than the control groups (70.4 ±12.0 and 65.3 ±10.1 μm, respectively; P<.001), whereas the milling/sintering groups exhibited significantly smaller values than the controls (P=.004). The milling groups showed significantly larger absolute marginal discrepancy than the control groups (137.4 ±29.0 and 139.2 ±18.9 μm, respectively; P<.05). In the selective laser melting and milling/sintering groups, the absolute marginal discrepancy values were material-specific (P<.05). Nonetheless, the milling/sintering groups yielded statistically comparable (P=.935) or smaller (P<.001) absolute marginal discrepancies to the control groups. The findings of this in vitro μCT study showed that the marginal fit values of the Co-Cr alloy greatly depended on the fabrication methods and, occasionally, the alloy systems. Fixed dental prostheses produced by using the milling/sintering technique can be considered clinically acceptable in terms of marginal fit. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Validation of cortical bone mineral density distribution using micro-computed tomography.

PubMed

Mashiatulla, Maleeha; Ross, Ryan D; Sumner, D Rick

2017-06-01

Changes in the bone mineral density distribution (BMDD), due to disease or drugs, can alter whole bone mechanical properties such as strength, stiffness and toughness. The methods currently available for assessing BMDD are destructive and two-dimensional. Micro-computed tomography (μCT) has been used extensively to quantify the three-dimensional geometry of bone and to measure the mean degree of mineralization, commonly called the tissue mineral density (TMD). The TMD measurement has been validated to ash density; however parameters describing the frequency distribution of TMD have not yet been validated. In the current study we tested the ability of μCT to estimate six BMDD parameters: mean, heterogeneity (assessed by the full-width-at-half-maximum (FWHM) and the coefficient of variation (CoV)), the upper and lower 5% cutoffs of the frequency distribution, and peak mineralization) in rat sized femoral cortical bone samples. We used backscatter scanning electron microscopy (bSEM) as the standard. Aluminum and hydroxyapatite phantoms were used to identify optimal scanner settings (70kVp, and 57μA, with a 1500ms integration time). When using hydroxyapatite samples that spanned a broad range of mineralization levels, high correlations were found between μCT and bSEM for all BMDD parameters (R 2 ≥0.92, p<0.010). When using cortical bone samples from rats and various species machined to mimic rat cortical bone geometry, significant correlations between μCT and bSEM were found for mean mineralization (R 2 =0.65, p<0.001), peak mineralization (R 2 =0.61, p<0.001) the lower 5% cutoff (R 2 =0.62, p<0.001) and the upper 5% cutoff (R 2 =0.33, p=0.021), but not for heterogeneity, measured by FWHM (R 2 =0.05, p=0.412) and CoV (R 2 =0.04, p=0.469). Thus, while mean mineralization and most parameters used to characterize the BMDD can be assessed with μCT in rat sized cortical bone samples, caution should be used when reporting the heterogeneity. Copyright © 2017 Elsevier Inc. All rights reserved.

A Novel Approach for Studying the Temporal Modulation of Embryonic Skeletal Development Using Organotypic Bone Cultures and Microcomputed Tomography

PubMed Central

Smith, Emma L.; Roberts, Carol A.

2012-01-01

Understanding the structural development of embryonic bone in a three dimensional framework is fundamental to developing new strategies for the recapitulation of bone tissue in latter life. We present an innovative combined approach of an organotypic embryonic femur culture model, microcomputed tomography (μCT) and immunohistochemistry to examine the development and modulation of the three dimensional structures of the developing embryonic femur. Isolated embryonic chick femurs were organotypic (air/liquid interface) cultured for 10 days in either basal, chondrogenic, or osteogenic supplemented culture conditions. The growth development and modulating effects of basal, chondrogenic, or osteogenic culture media of the embryonic chick femurs was investigated using μCT, immunohistochemistry, and histology. The growth and development of noncultured embryonic chick femur stages E10, E11, E12, E13, E15, and E17 were very closely correlated with increased morphometric indices of bone formation as determined by μCT. After 10 days in the organotpyic culture set up, the early aged femurs (E10 and E11) demonstrated a dramatic response to the chondrogenic or osteogenic culture conditions compared to the basal cultured femurs as determined by a change in μCT morphometric indices and modified expression of chondrogenic and osteogenic markers. Although the later aged femurs (E12 and E13) increased in size and structure after 10 days organotpypic culture, the effects of the osteogenic and chondrogenic organotypic cultures on these femurs were not significantly altered compared to basal conditions. We have demonstrated that the embryonic chick femur organotpyic culture model combined with the μCT and immunohistochemical analysis can provide an integral methodology for investigating the modulation of bone development in an ex vivo culture setting. Hence, these interdisciplinary techniques of μCT and whole organ bone cultures will enable us to delineate some of the temporal, structural developmental paradigms and modulation of bone tissue formation to underpin innovative skeletal regenerative technology for clinical therapeutic strategies in musculoskeletal trauma and diseases. PMID:22472170

In vivo longitudinal micro-CT study of bent long limb bones in rat offspring.

PubMed

De Schaepdrijver, Luc; Delille, Peter; Geys, Helena; Boehringer-Shahidi, Christian; Vanhove, Christian

2014-07-01

Micro-computed X-ray tomography (micro-CT) has been reported as a reliable method to assess ex vivo rat and rabbit fetal skeletons in embryo-fetal developmental toxicity studies. Since micro-CT is a non-invasive imaging modality it has the potential for longitudinal, in vivo investigation of postnatal skeletal development. This is the first paper using micro-CT to assess the reversibility of drug-induced bent long bones in a longitudinal study from birth to early adulthood in rat offspring. Analysis of the scans obtained on postnatal Day 0, 7, 21 and 80 showed complete recovery or repair of the bent long limb bones (including the scapula) within the first 3 weeks. When assessing risk the ability to demonstrate recovery is highly advantageous when interpreting such transient skeletal change. In summary, in vivo micro-CT of small laboratory animals can aid in non-clinical safety assessment, particularly for specific mechanistic purposes or to address a particular concern in developmental biology. Copyright © 2014 Elsevier Inc. All rights reserved.

Microcomputer Use in a Labor Studies Environment.

ERIC Educational Resources Information Center

Sorcinelli, Gino; Spencer, David C.

1987-01-01

Describes the development and classroom application of a microcomputer-assisted collective bargaining simulation by Indiana University's Division of Labor Studies. Student involvement in the simulation is described, instructional development techniques used in designing the simulation are discussed, and benefits of the simulation are reviewed.…

Microcomputer Technology in Schools: Issues for Research.

ERIC Educational Resources Information Center

Kane, Janet H.; And Others

This exploratory, multi-disciplinary study, which was undertaken to identify a research agenda for the educational implementation and impact of microprocessing technology, used case study methodology to explore the relationship between the social contexts and the microcomputer innovation. Three geographically distinct school districts with a…

Visible-Light Initiated Free-Radical/Cationic Ring-Opening Hybrid Photopolymerization of Methacrylate/Epoxy: Polymerization Kinetics, Crosslinking Structure, and Dynamic Mechanical Properties.

PubMed

Ge, Xueping; Ye, Qiang; Song, Linyong; Misra, Anil; Spencer, Paulette

2015-04-01

The effects of polymerization kinetics and chemical miscibility on the crosslinking structure and mechanical properties of polymers cured by visible-light initiated free-radical/cationic ring-opening hybrid photopolymerization are determined. A three-component initiator system is used and the monomer system contains methacrylates and epoxides. The photopolymerization kinetics is monitored in situ by Fourier transform infrared-attenuated total reflectance. The crosslinking structure is studied by modulated differential scanning calorimetry and dynamic mechanical analysis. X-ray microcomputed tomography is used to evaluate microphase separation. The mechanical properties of polymers formed by hybrid formed by free-radical polymerization. These investigations mark the first time that the benefits of the chain transfer reaction between epoxy and hydroxyl groups of methacrylate, on the crosslinking network and microphase separation during hybrid visible-light initiated photopolymerization, have been determined.

Biocompatibility of PCL/PLGA-BCP porous scaffold for bone tissue engineering applications.

PubMed

Thi Hiep, Nguyen; Chan Khon, Huynh; Dai Hai, Nguyen; Byong-Taek, Lee; Van Toi, Vo; Thanh Hung, Le

2017-06-01

In this study, biomimic porous polycaprolactone/poly (lactide-co-glycolide) loading biphasic tricalcium phosphate (PCL/PLGA-BCP) scaffolds were fabricated successfully by solvent evaporation method. The distribution of biphasic tricalcium phosphate (BCP) in polycaprolactone/poly (lactide-co-glycolide) (PCL/PLGA) scaffold was confirmed by micro-computed tomography (micro-CT) scanning, scanning electron microscope (SEM) observation and Energy-dispersive X-ray Spectroscopy (EDS) analysis. The hydrophilicity of the scaffolds was confirmed by contact angle measurement. In in vitro experiments, proliferation of human bone marrow mesenchymal stem cell (hBMSCs) and its osteoblastic differentiation on scaffold were assessed for 1, 2 and 3 weeks using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, fluorescence observation, hematoxylin & eosin (H&E) staining and real-time polymerase chain reaction (RT-PCR). In in vivo experiments, ossification was observed using micro-CT analysis and histological staining.

Fiber Orientation Effects in Fused Filament Fabrication of Air-Cooled Heat Exchangers

NASA Astrophysics Data System (ADS)

Mulholland, T.; Goris, S.; Boxleitner, J.; Osswald, T. A.; Rudolph, N.

2018-03-01

Fused filament fabrication (FFF) is a type of additive manufacturing based on material extrusion that has long been considered a prototyping technology. However, the right application of material, process, and product can be used for manufacturing of end-use products, such as air-cooled heat exchangers made by adding fillers to the base polymer, enhancing the thermal conductivity. Fiber fillers lead to anisotropic thermal conductivity, which is governed by the process-induced fiber orientation. This article presents an experimental study on the microstructure-property relationship for carbon fiber-filled polyamide used in FFF. The fiber orientation is measured by micro-computed tomography, and the thermal conductivity of manufactured samples is measured. Although the thermal conductivity is raised by more than three times in the fiber orientation direction at a load of only 12 vol.%, the enhancement is low in the other directions, and this anisotropy, along with certain manufacturing restrictions, influences the final part performance.

Technical Report: Correlation Between the Repair of Cartilage and Subchondral Bone in an Osteochondral Defect Using Bilayered, Biodegradable Hydrogel Composites.

PubMed

Lu, Steven; Lam, Johnny; Trachtenberg, Jordan E; Lee, Esther J; Seyednejad, Hajar; van den Beucken, Jeroen J J P; Tabata, Yasuhiko; Kasper, F Kurtis; Scott, David W; Wong, Mark E; Jansen, John A; Mikos, Antonios G

2015-12-01

The present work investigated correlations between cartilage and subchondral bone repair, facilitated by a growth factor-delivering scaffold, in a rabbit osteochondral defect model. Histological scoring indices and microcomputed tomography morphological parameters were used to evaluate cartilage and bone repair, respectively, at 6 and 12 weeks. Correlation analysis revealed significant associations between specific cartilage indices and subchondral bone parameters that varied with location in the defect (cortical vs. trabecular region), time point (6 vs. 12 weeks), and experimental group (insulin-like growth factor-1 only, bone morphogenetic protein-2 only, or both growth factors). In particular, significant correlations consistently existed between cartilage surface regularity and bone quantity parameters. Overall, correlation analysis between cartilage and bone repair provided a fuller understanding of osteochondral repair and can help drive informed studies for future osteochondral regeneration strategies.

[Nasolabial muscle finite-element study and clinical application].

PubMed

Yin, Ningbei; Wu, Jiajun; Chen, Bo; Wang, Yongqian; Song, Tao; Ma, Hengyuan

2015-05-01

To investigate the nasolabial muscle anatomy and biomechanical characteristics. Micro-computed tomography scan was performed in 8 cases of spontaneous abortion fetus lip nasal specimens to construct a three-dimensional model. The nasolabial muscle structure was analyzed using Mimics software. The three-dimensional configuration model of nasolabial muscle was established based on local anatomy and tissue section, and compared with tissue section. Three dimensional finite element analysis was performed on lip nasal muscle related biomechanics and surface deformation in Application verification was carried out in 263 cases of microform cleft lip surgery. There was close relationship between nasolabial muscle. The nasolabial muscle tension system was constituted, based on which a new cleft lip repair surgery was designed and satisfied results were achieved. There is close relationship among nasolabial muscle in anatomy, histology and biomechanics. To obtain better effect, cleft lip repair should be performed on the basis of recovering muscle tension system.

Qualification of Ti6Al4V ELI Alloy Produced by Laser Powder Bed Fusion for Biomedical Applications

NASA Astrophysics Data System (ADS)

Yadroitsev, I.; Krakhmalev, P.; Yadroitsava, I.; Du Plessis, A.

2018-03-01

Rectangular Ti6Al4V extralow interstitials (ELI) samples were manufactured by laser powder bed fusion (LPBF) in vertical and horizontal orientations relative to the build platform and subjected to various heat treatments. Detailed analyses of porosity, microstructure, residual stress, tensile properties, fatigue, and fracture surfaces were performed based on x-ray micro-computed tomography, scanning electron microscopy, and x-ray diffraction methods. The types of fracture and the tensile fracture mechanisms of the LPBF Ti6Al4V ELI alloy were also studied. Detailed analysis of the microstructure and the corresponding mechanical properties were compared against standard specifications for conventional Ti6Al4V alloy for use in surgical implant applications. Conclusions regarding the mechanical properties and heat treatment of LPBF Ti6Al4V ELI for biomedical applications are made.

Entomological Collections in the Age of Big Data.

PubMed

Short, Andrew Edward Z; Dikow, Torsten; Moreau, Corrie S

2018-01-07

With a million described species and more than half a billion preserved specimens, the large scale of insect collections is unequaled by those of any other group. Advances in genomics, collection digitization, and imaging have begun to more fully harness the power that such large data stores can provide. These new approaches and technologies have transformed how entomological collections are managed and utilized. While genomic research has fundamentally changed the way many specimens are collected and curated, advances in technology have shown promise for extracting sequence data from the vast holdings already in museums. Efforts to mainstream specimen digitization have taken root and have accelerated traditional taxonomic studies as well as distribution modeling and global change research. Emerging imaging technologies such as microcomputed tomography and confocal laser scanning microscopy are changing how morphology can be investigated. This review provides an overview of how the realization of big data has transformed our field and what may lie in store.

In Vivo Wear Performance of Cobalt-Chromium Versus Oxidized Zirconium Femoral Total Knee Replacements.

PubMed

Gascoyne, Trevor C; Teeter, Matthew G; Guenther, Leah E; Burnell, Colin D; Bohm, Eric R; Naudie, Douglas R

2016-01-01

This study examines the damage and wear on the polyethylene (PE) inserts from 52 retrieved Genesis II total knee replacements to identify differences in tribological performance between matched pairs of cobalt-chromium (CoCr) and oxidized zirconium (OxZr) femoral components. Observer damage scoring and microcomputed tomography were used to quantify PE damage and wear, respectively. No significant differences were found between CoCr and OxZr groups in terms of PE insert damage, surface penetration, or wear. No severe damage such as cracking or delamination was noted on any of the 52 PE inserts. Observer damage scoring did not correlate with penetrative or volumetric PE wear. The more costly OxZr femoral component does not demonstrate clear tribological benefit over the standard CoCr component in the short term with this total knee replacement design. Copyright © 2016 Elsevier Inc. All rights reserved.

Analysis of the enamel hypoplasia using micro-CT scanner versus classical method.

PubMed

Marchewka, Justyna; Skrzat, Janusz; Wróbel, Andrzej

2014-01-01

This article demonstrates the use of micro-CT scanning of the teeth surface for recognizing and evaluating severity of the enamel hypoplasia. To test capabilities of the microtomography versus classical method of evaluation hypoplastic defects of the enamel we selected two human teeth (C, M(2)) showing different types of enamel hypoplasia: linear, pits, and groove. Examined samples derive from archeological material dated on XVII-XVIII AD and excavated in Poland. In the current study we proved that micro-CT scanning is a powerful technique not only for imaging all kinds of the enamel hypoplasia but also allows to perform accurate measurements of the enamel defects. We figure out that contrary to the classical method of scoring enamel defects, the micro-computed tomography yields adequate data which serve for estimating the length of stress episode and length of interval between them.

Dynamic tensile fracture of mortar at ultra-high strain-rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erzar, B., E-mail: benjamin.erzar@cea.fr; Buzaud, E.; Chanal, P.-Y.

2013-12-28

During the lifetime of a structure, concrete and mortar may be exposed to highly dynamic loadings, such as impact or explosion. The dynamic fracture at high loading rates needs to be well understood to allow an accurate modeling of this kind of event. In this work, a pulsed-power generator has been employed to conduct spalling tests on mortar samples at strain-rates ranging from 2 × 10{sup 4} to 4 × 10{sup 4} s{sup −1}. The ramp loading allowed identifying the strain-rate anytime during the test. A power law has been proposed to fit properly the rate-sensitivity of tensile strength of thismore » cementitious material over a wide range of strain-rate. Moreover, a specimen has been recovered damaged but unbroken. Micro-computed tomography has been employed to study the characteristics of the damage pattern provoked by the dynamic tensile loading.« less

Bone Histology and Primary Growth Rates in Hatchling Titanosaurs from Madagascar: New Insights from Micro-Computed Tomography

NASA Astrophysics Data System (ADS)

Bagley, B. C.; Whitney, M.; Rogers, K. C.

2012-12-01

Sauropods are the largest known terrestrial vertebrates and exhibit a greater ontogenetic variation in body size than any other taxon. More than 120 species of sauropods are known from the Jurassic and Cretaceous, and a wealth of specimens documents their enormous adult body sizes. Juvenile sauropods, in contrast, are rare. Though titanosaur eggs containing embryos have been recovered, to date the smallest known post-hatching juveniles are only a little less than half of known adult size, and details of the earliest stages of sauropod ontogeny remain particularly poorly understood. Here we report on two partial skeletons of hatchling Rapetosaurus krausei, a titanosaur from the Upper Cretaceous Maevarano Formation of Madagascar, and provide important new data on primary early stage growth rates in sauropods. The two partial skeletons come from different localities in the Anembalemba Member of the Maevarano Formation. There is no duplication of elements for either specimen. Comparison of greatest length ratios for appendicular elements to those of a complete sub-adult Rapetosaurus confirms that there are only two individuals present, that there is no significant allometry in Rapetosaurus postcranial ontogeny, and that each individual is less than 15% adult size. The smaller specimen includes a sacral neural arch, three caudal centra, three caudal neural arches, left pubis, right femur (maximum length [ml] = 19.3 cm), tibia (ml = 12.7 cm), and metacarpal III, left and right fibulae, humeri, and metatarsal I, and a phalanx. The larger specimen includes a caudal centrum and neural arch, right metacarpal I, right tibia (ml = 17.9 cm), and left metacarpal IV. In order to non-destructively sample these exceptional Rapetosaurus juvenile elements, we employed micro-computed tomography to garner bone histology data. The micro-computed tomography was carried out using an X5000 high-resolution microfocus X-ray CT system located in the Department of Earth Sciences, University of Minnesota. The microfocus head has a minimum focal spot size of < 6 microns and the detector has a pixel pitch of 74.8 μm. Machine parameters (e.g. voltage, current, tube to detector distance) vary based on sample size and desired magnification. For this study 70-100 kV (260-370 μA) was sufficient to penetrate the samples and obtain good contrast. We were able to achieve an effective pixel pitch of 36-48 μm for the larger samples and 14-28 μm for sub-volumes. 2-D radiographs were collected and these data were reconstructed to produce a 3-D volume for visual analysis, and slices of the 3-D volume for quantitative analysis. Our results indicate that primary bone growth in Rapetosaurus is highly vascularized woven and fibrolamellar bone. However, even in these very small juvenile individuals, endosteal remodeling is common at the mid-diaphysis and extends in some areas into the mid-cortex. The presence of a single line of arrested growth is recorded in each individual. These results are surprising given the small size of the elements, and support the hypothesis that intensive remodeling observed in the bones of older juvenile Rapetosaurus may be dictated, at least in part, by resource limitations during periods of drought/ecological stress recorded in the Maevarano Formation of Madagascar.

The Microcomputer Revolution.

ERIC Educational Resources Information Center

Fosdick, Howard

1980-01-01

Examines the development of the microcomputer and focuses on its potential for library automation. The characteristics of microcomputers and minicomputers are contrasted and a selected annotated bibliography includes a list of specialty magazines on microcomputers. (RAA)

Investigation of a pre-clinical mandibular bone notch defect model in miniature pigs: clinical computed tomography, micro-computed tomography, and histological evaluation.

PubMed

Carlisle, Patricia L; Guda, Teja; Silliman, David T; Lien, Wen; Hale, Robert G; Brown Baer, Pamela R

2016-02-01

To validate a critical-size mandibular bone defect model in miniature pigs. Bilateral notch defects were produced in the mandible of dentally mature miniature pigs. The right mandibular defect remained untreated while the left defect received an autograft. Bone healing was evaluated by computed tomography (CT) at 4 and 16 weeks, and by micro-CT and non-decalcified histology at 16 weeks. In both the untreated and autograft treated groups, mineralized tissue volume was reduced significantly at 4 weeks post-surgery, but was comparable to the pre-surgery levels after 16 weeks. After 16 weeks, CT analysis indicated that significantly greater bone was regenerated in the autograft treated defect than in the untreated defect (P=0.013). Regardless of the treatment, the cortical bone was superior to the defect remodeled over 16 weeks to compensate for the notch defect. The presence of considerable bone healing in both treated and untreated groups suggests that this model is inadequate as a critical-size defect. Despite healing and adaptation, the original bone geometry and quality of the pre-injured mandible was not obtained. On the other hand, this model is justified for evaluating accelerated healing and mitigating the bone remodeling response, which are both important considerations for dental implant restorations.

Test plan for 32-bit microcomputers for the Water Resources Division; Chapter A, Test plan for acquisition of prototype 32-bit microcomputers

USGS Publications Warehouse

Hutchison, N.E.; Harbaugh, A.W.; Holloway, R.A.; Merk, C.F.

1987-01-01

The Water Resources Division (WRD) of the U.S. Geological Survey is evaluating 32-bit microcomputers to determine how they can complement, and perhaps later replace, the existing network of minicomputers. The WRD is also designing a National Water Information System (NWIS) that will combine and integrate the existing National Water Data Storage and Retrieval System (WATSTORE), National Water Data Exchange (NAWDEX), and components of several other existing systems. The procedures and testing done in a market evaluation of 32-bit microcomputers are documented. The results of the testing are documented in the NWIS Project Office. The market evaluation was done to identify commercially available hardware and software that could be used for implementing early NWIS prototypes to determine the applicability of 32-bit microcomputers for data base and general computing applications. Three microcomputers will be used for these prototype studies. The results of the prototype studies will be used to compile requirements for a Request for Procurement (RFP) for hardware and software to meet the WRD 's needs in the early 1990's. The identification of qualified vendors to provide the prototype hardware and software included reviewing industry literature, and making telephone calls and personal visits to prospective vendors. Those vendors that appeared to meet general requirements were required to run benchmark tests. (Author 's abstract)

The dental cavities of equine cheek teeth: three-dimensional reconstructions based on high resolution micro-computed tomography

PubMed Central

2012-01-01

Background Recent studies reported on the very complex morphology of the pulp system in equine cheek teeth. The continuous production of secondary dentine leads to distinct age-related changes of the endodontic cavity. Detailed anatomical knowledge of the dental cavities in all ages is required to explain the aetiopathology of typical equine endodontic diseases. Furthermore, data on mandibular and maxillary pulp systems is in high demand to provide a basis for the development of endodontic therapies. However, until now examination of the pulp cavity has been based on either sectioned teeth or clinical computed tomography. More precise results were expected by using micro-computed tomography with a resolution of about 0.1 mm and three-dimensional reconstructions based on previous greyscale analyses and histological verification. The aim of the present study was to describe the physiological configurations of the pulp system within a wide spectrum of tooth ages. Results Maxillary teeth: All morphological constituents of the endodontic cavity were present in teeth between 4 and 16 years: Triadan 06s displayed six pulp horns and five root canals, Triadan 07-10s five pulp horns and four root canals and Triadan 11s seven pulp horns and four to six root canals. A common pulp chamber was most frequent in teeth ≤5 years, but was found even in a tooth of 9 years. A large variety of pulp configurations was observed within 2.5 and 16 years post eruption, but most commonly a separation into mesial and distal pulp compartments was seen. Maxillary cheek teeth showed up to four separate pulp compartments but the frequency of two, three and four pulp compartments was not related to tooth age (P > 0.05). In Triadan 06s, pulp horn 6 was always connected to pulp horns 1 and 3 and root canal I. In Triadan 11s, pulp horns 7 and 8 were present in variable constitutions. Mandibular teeth: A common pulp chamber was present in teeth up to 15 years, but most commonly seen in teeth ≤5 years. A segmented pulp system was found in 72% of the investigated teeth. Segmentation into separate mesial and distal pulp compartments was most commonly present. Pulp horn 4 coalesced either with the mesial pulp horns 1 and 3 or with the distal pulp horns 2 and 5. Conclusions Details of the pulpar anatomy of equine cheek teeth are provided, supporting the continuous advancement in endodontic therapy. Numerous individual configurations of the pulp system were obtained in maxillary cheek teeth, but much less variability was seen in mandibular cheek teeth. PMID:23006500

Analysis of plastic deformation in cortical bone after insertion of coated and non-coated self-tapping orthopaedic screws.

PubMed

Koistinen, A P; Korhonen, H; Kiviranta, I; Kröger, H; Lappalainen, R

2011-07-01

Insertion of internal fracture fixation devices, such as screws, mechanically weakens the bone. Diamond-like carbon has outstanding tribology properties which may decrease the amount of damage in tissue. The purpose of this study was to investigate methods for quantification of cortical bone damage after orthopaedic bone screw insertion and to evaluate the effect of surface modification on tissue damage. In total, 48 stainless steel screws were inserted into cadaver bones. Half of the screws were coated with a smooth amorphous diamond coating. Geometrical data of the bones was determined by peripheral quantitative computed tomography. Thin sections of the bone samples were prepared after screw insertion, and histomorphometric evaluation of damage was performed on images obtained using light microscopy. Micro-computed tomography and scanning electron microscopy were also used to examine tissue damage. A positive correlation was found between tissue damage and the geometric properties of the bone. The age of the cadaver significantly affected the bone mineral density, as well as the damage perimeter and diameter of the screw hole. However, the expected positive effect of surface modification was probably obscured by large variations in the results and, thus, statistically significant differences were not found in this study. This can be explained by natural variability in bone tissue, which also made automated image analysis difficult.

Accuracy of volumetric measurement of simulated root resorption lacunas based on cone beam computed tomography.

PubMed

Wang, Y; He, S; Guo, Y; Wang, S; Chen, S

2013-08-01

To evaluate the accuracy of volumetric measurement of simulated root resorption cavities based on cone beam computed tomography (CBCT), in comparison with that of Micro-computed tomography (Micro-CT) which served as the reference. The State Key Laboratory of Oral Diseases at Sichuan University. Thirty-two bovine teeth were included for standardized CBCT scanning and Micro-CT scanning before and after the simulation of different degrees of root resorption. The teeth were divided into three groups according to the depths of the root resorption cavity (group 1: 0.15, 0.2, 0.3 mm; group 2: 0.6, 1.0 mm; group 3: 1.5, 2.0, 3.0 mm). Each depth included four specimens. Differences in tooth volume before and after simulated root resorption were then calculated from CBCT and Micro-CT scans, respectively. The overall between-method agreement of the measurements was evaluated using the concordance correlation coefficient (CCC). For the first group, the average volume of resorption cavity was 1.07 mm(3) , and the between-method agreement of measurement for the volume changes was low (CCC = 0.098). For the second and third groups, the average volumes of resorption cavities were 3.47 and 6.73 mm(3) respectively, and the between-method agreements were good (CCC = 0.828 and 0.895, respectively). The accuracy of 3-D quantitative volumetric measurement of simulated root resorption based on CBCT was fairly good in detecting simulated resorption cavities larger than 3.47 mm(3), while it was not sufficient for measuring resorption cavities smaller than 1.07 mm(3) . This method could be applied in future studies of root resorption although further studies are required to improve its accuracy. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of bone response to titanium-coated polymethyl methacrylate resin (PMMA) implants by X-ray tomography.

PubMed

Shalabi, Manal M; Wolke, Johannes G C; Cuijpers, Vincent M J I; Jansen, John A

2007-10-01

High-resolution three-dimensional data about the bone response to oral implants can be obtained by using microfocus computer tomography. However, a disadvantage is that metallic implants cause streaking artifacts due to scattering of X-rays, which prevents an accurate evaluation of the interfacial bone-to-implant contact. It has been suggested that the use of thin titanium coatings deposited on polymeric implants can offer an alternative option for analyzing bone contact using micro-CT imaging. Consequently, the aim of the current study was to investigate bone behavior to titanium-coated polymethylmethacrylate (PMMA) implants by micro-CT and histological evaluation. For the experiment titanium-coated PMMA implants were used. The implants had a machined threaded appearance and were provided with a 400-500 nm thick titanium coating. The implants were inserted in the right or left tibia of 10 goats. After an implantation period of 12 weeks the implants were retrieved and prepared for micro-computer tomography (microCT), light microscopy, and X-ray microanalysis. The micro-CT showed that the screw-threads and typical implant configuration were well maintained through the installation procedure. Overall, histological responses showed that the titanium-coated implants were well tolerated and caused no atypical tissue response. In addition, the bone was seen in direct contact with the titanium-coated layer. The X-ray microanalysis results confirmed the light microscopical data. In conclusion, the obtained results proof the final use of titanium-coated PMMA implants for evaluation of the bone-implant response using microCT. However, this study also confirms that for a proper analysis of the bone-implant interface the additional use of microscopical techniques is still required.

Time-dependent behavior of porcine periodontal ligament: A combined experimental, numeric in-vitro study.

PubMed

Knaup, Thomas Johannes; Dirk, Cornelius; Reimann, Susanne; Keilig, Ludger; Eschbach, Meike; Korbmacher-Steiner, Heike; Bourauel, Christoph

2018-01-01

The aim of this study was to analyze the time-dependent in-vitro behavior of the periodontal ligament (PDL) by determining the material parameters using specimens of porcine jawbone. Time-dependent material parameters to be determined were expected to complement the results from earlier biomechanical studies. Five mandibular deciduous porcine premolars were analyzed in a combined experimental-numeric study. After selecting suitable specimens (excluding root resorption) and preparing the measurement system, the specimens were deflected by a distance of 0.2 mm at loading times of 0.2, 0.5, 1, 2, 5, 10, and 60 seconds. The deflection of the teeth was determined via a laser optical system, and the resulting forces and torques were measured. To create the finite element models, a microcomputed tomography scanner was used to create 3-dimensional x-ray images of the samples. The individual structures (tooth, PDL, bone) of the jaw segments were reconstructed using a self-developed reconstruction program. A comparison between experiment and simulation was conducted using the results from finite element simulations. Via iterative parameter adjustments, the material parameters (Young's modulus and Poisson's ratio) of the PDL were assessed at different loading velocities. The clinically observed effect of a distinct increase in force during very short periods of loading was confirmed. Thus, a force of 2.6 N (±1.5 N) was measured at the shortest stress duration of 0.2 seconds, and a force of 1.0 N (±0.5 N) was measured at the longest stress duration of 60 seconds. The numeric determination of the material parameters showed bilinear behavior with a median value of the first Young's modulus between 0.06 MPa (2 seconds) and 0.04 MPa (60 seconds), and the second Young's modulus between 0.30 MPa (10 seconds) and 0.20 MPa (60 seconds). The ultimate strain marking the transition from the first to the second Young's modulus remained almost unchanged with a median value of 6.0% for all loading times. A combined experimental-numeric analysis is suitable for determining the material properties of the PDL. Microcomputed tomography allows high-precision recordings with only minimum effort. This study confirms the assumption of time dependency and nonlinearity of previous studies. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Micro-Scale Distribution of CA4+ in Ex Vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging

NASA Astrophysics Data System (ADS)

Karhula, Sakari S.; Finnilä, Mikko A.; Freedman, Jonathan D.; Kauppinen, Sami; Valkealahti, Maarit; Lehenkari, Petri; Pritzker, Kenneth P. H.; Nieminen, Heikki J.; Snyder, Brian D.; Grinstaff, Mark W.; Saarakkala, Simo

2017-08-01

Contrast-enhanced micro-computed tomography (CEµCT) with cationic and anionic contrast agents reveals glycosaminoglycan (GAG) content and distribution in articular cartilage (AC). The advantage of using cationic stains (e.g. CA4+) compared to anionic stains (e.g. Hexabrix®), is that it distributes proportionally with GAGs, while anionic stain distribution in AC is inversely proportional to the GAG content. To date, studies using cationic stains have been conducted with sufficient resolution to study its distributions on the macro-scale, but with insufficient resolution to study its distributions on the micro-scale. Therefore, it is not known whether the cationic contrast agents accumulate in extra/pericellular matrix and if they interact with chondrocytes. The insufficient resolution has also prevented to answer the question whether CA4+ accumulation in chondrons could lead to an erroneous quantification of GAG distribution with low-resolution µCT setups. In this study, we use high-resolution µCT to investigate whether CA4+ accumulates in chondrocytes, and further, to determine whether it affects the low-resolution ex vivo µCT studies of CA4+ stained human AC with varying degree of osteoarthritis. Human osteochondral samples were immersed in three different concentrations of CA4+ (3 mgI/ml, 6mgI/ml, and 24 mgI/ml) and imaged with high-resolution µCT at several timepoints. Different uptake diffusion profiles of CA4+ were observed between the segmented chondrons and the rest of the tissue. While the X-ray -detected CA4+ concentration in chondrons was greater than in the rest of the AC, its contribution to the uptake into the whole tissue was negligible and in line with macro-scale GAG content detected from histology. The efficient uptake of CA4+ into chondrons and surrounding territorial matrix can be explained by the micro-scale distribution of GAG content. CA4+ uptake in chondrons occurred regardless of the progression stage of osteoarthritis in the samples and the relative difference between the interterritorial matrix and segmented chondron area was less than 4%. To conclude, our results suggest that GAG quantification with CEµCT is not affected by the chondron uptake of CA4+. This further confirms the use of CA4+ for macro-scale assessment of GAG throughout the AC, and highlight the capability of studying chondron properties in 3D at the micro scale.

South America Map Study.

ERIC Educational Resources Information Center

Canipe, Stephen L.

A simple "menu-driven" microcomputer program on map studies, designed to teach the geography of South America and certain economic facts about its countries, is presented. The program is written for an Apple II+ or Apple IIe computer; use on any other microcomputer will require substantial changes due to high resolution drawings and…

Microcomputer software for storm drain hydraulic gradeline computation.

DOT National Transportation Integrated Search

1987-01-01

A microcomputer software module was developed for the computation of hydraulic gradeline in storm sewer systems. The computer module has been attached to the program '"HYDRA", which is being adopted by the FHWA organized Pooled Fund Study. on Integra...

An in vivo model to assess magnesium alloys and their biological effect on human bone marrow stromal cells.

PubMed

Yoshizawa, Sayuri; Chaya, Amy; Verdelis, Kostas; Bilodeau, Elizabeth A; Sfeir, Charles

2015-12-01

Magnesium (Mg) alloys have many unique qualities which make them ideal candidates for bone fixation devices, including biocompatibility and degradation in vivo. Despite a rise in Mg alloy production and research, there remains no standardized system to assess their degradation or biological effect on human stem cells in vivo. In this study, we developed a novel in vivo model to assess Mg alloys for craniofacial and orthopedic applications. Our model consists of a collagen sponge seeded with human bone marrow stromal cells (hBMSCs) around a central Mg alloy rod. These scaffolds were implanted subcutaneously in mice and analyzed after eight weeks. Alloy degradation and biological effect were determined by microcomputed tomography (microCT), histological staining, and immunohistochemistry (IHC). MicroCT showed greater volume loss for pure Mg compared to AZ31 after eight weeks in vivo. Histological analysis showed that hBMSCs were retained around the Mg implants after 8 weeks. Furthermore, immunohistochemistry showed the expression of dentin matrix protein 1 and osteopontin around both pure Mg and AZ31 with implanted hBMSCs. In addition, histological sections showed a thin mineral layer around all degrading alloys at the alloy-tissue interface. In conclusion, our data show that degrading pure Mg and AZ31 implants are cytocompatible and do not inhibit the osteogenic property of hBMSCs in vivo. These results demonstrate that this model can be used to efficiently assess the biological effect of corroding Mg alloys in vivo. Importantly, this model may be modified to accommodate additional cell types and clinical applications. Magnesium (Mg) alloys have been investigated as ideal candidates for bone fixation devices due to high biocompatibility and degradation in vivo, and there is a growing need of establishing an efficient in vivo material screening system. In this study, we assessed degradation rate and biological effect of Mg alloys by transplanting Mg alloy rod with human bone marrow stromal cells seeded on collagen sponge subcutaneously in mice. After 8 weeks, samples were analyzed by microcomputed tomography and histological staining. Our data show that degrading Mg alloys are cytocompatible and do not inhibit the osteogenic property of hBMSCs in vivo. These results demonstrate that this model can be used to efficiently assess the biological effect of corroding Mg alloys in vivo. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Physical properties of root cementum: part 20. Effect of fluoride on orthodontically induced root resorption with light and heavy orthodontic forces for 4 weeks: a microcomputed tomography study.

PubMed

Karadeniz, Ersan Ilsay; Gonzales, Carmen; Nebioglu-Dalci, Oyku; Dwarte, Dennis; Turk, Tamer; Isci, Devrim; Sahin-Saglam, Aynur M; Alkis, Huseyin; Elekdag-Turk, Selma; Darendeliler, M Ali

2011-11-01

The major side effect of orthodontic treatment is orthodontically induced inflammatory root resorption. Fluoride was previously shown to reduce the volume of the root resorption craters in rats. However, the effect of fluoride on orthodontically induced inflammatory root resorption in humans has not yet been investigated. The aim of this study was to investigate the effect of high and low amounts of fluoride intake from birth on orthodontically induced inflammatory root resorption under light (25 g) and heavy (225 g) force applications. Forty-eight patients who required maxillary premolar extractions as part of their orthodontic treatment were selected from 2 cities in Turkey with high and low fluoride concentrations in the public water of ≥ 2 and ≤ 0.05 ppm, respectively. The patients were randomly separated into 4 groups of 12 each: group 1, high fluoride intake and heavy force; group 2, low fluoride intake and heavy force; group 3, high fluoride intake and light force; and group 4, low fluoride intake and light force. Light or heavy buccal tipping orthodontic forces were applied on the maxillary first premolars for 28 days. At day 28, the teeth were extracted, and the samples were analyzed with microcomputed tomography. Fluoride reduced the volume of root resorption craters in all groups; however, this effect was significantly different with high force application (P = 0.015). It was also found that light forces caused less root resorption than heavy forces. There was no statistical difference in the amount of root resorption observed on root surfaces (buccal, lingual, mesial, and distal) in all groups. However, the middle third of the roots showed the least root resorption. With high fluoride intake and heavy force application, less root resorption was found in all root surfaces and root thirds. Fluoride may reduce the volume of root resorption craters. This effect is significant with heavy force applications (P <0.05). The cervical and apical thirds of the root showed significantly greater root resorption after the application of buccal tipping force for 4 weeks. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

End-Use Load and Conservation Assessment Program : Co-Instrumentation Test of Two Microcomputer-Based Energy Monitoring Systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fishbaugher, M. J.

1985-05-01

The decreasing cost of microcomputers along with improvements in power metering circuitry have changed the way in which electrical energy use is monitored. Although utilities still rely on kilowatt-hour (kWh) meters for billing purposes, a microcomputer-based monitoring system is used when greater temporal and end-use resolution is desired. Because these types of monitoring systems will be used increasingly in large-scale conservation and end-use studies, it is important that their performance be analyzed to determine their accuracy. A co-instrumentation test was devised in which two such microcomputer-based monitoring systems made simultaneous measurements of electrical end-uses in two commercial buildings. The analysismore » of the co-instrumentation data aids in the evaluation of microcomputer-based monitoring systems used for end-use measurements. Separate and independent data loggers were used to measure the same loads simultaneously. In addition to these two systems, a utility billing meter measured the total energy use in each building during the co-instrumentation test. The utility's meters provided a relatively accurate standard by which the performance of both loggers could be judged. The comparison between the SCL and PNL microcomputer-based loggers has shown that power measurement techniques directly affect system performance. The co-instrumentation test has shown that there are certain standards that a monitoring system must meet if it is to perform well. First, it is essential to calibrate a microcomputer-based logger against a known standard load before the system is installed. Second, a microcomputer-based system must have some way of accounting for power factors. Recent advances in power metering circuitry have made it relatively easy to apply these power factors automatically in real time.« less

Microcomputers in Geography.

ERIC Educational Resources Information Center

Snaden, James N.; And Others

Geographers in the United States rely heavily on microcomputers. They employ microcomputers to enhance three general categories of tasks: word processing and other productivity needs, geographic instruction, and discipline-specific applications. Word processing and desktop publishing continue to be the primary uses of microcomputers by…

Characterization of synthetic foam structures used to manufacture artificial vertebral trabecular bone.

PubMed

Fürst, David; Senck, Sascha; Hollensteiner, Marianne; Esterer, Benjamin; Augat, Peter; Eckstein, Felix; Schrempf, Andreas

2017-07-01

Artificial materials reflecting the mechanical properties of human bone are essential for valid and reliable implant testing and design. They also are of great benefit for realistic simulation of surgical procedures. The objective of this study was therefore to characterize two groups of self-developed synthetic foam structures by static compressive testing and by microcomputed tomography. Two mineral fillers and varying amounts of a blowing agent were used to create different expansion behavior of the synthetic open-cell foams. The resulting compressive and morphometric properties thus differed within and also slightly between both groups. Apart from the structural anisotropy, the compressive and morphometric properties of the synthetic foam materials were shown to mirror the respective characteristics of human vertebral trabecular bone in good approximation. In conclusion, the artificial materials created can be used to manufacture valid synthetic bones for surgical training. Further, they provide novel possibilities for studying the relationship between trabecular bone microstructure and biomechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Microstructures and properties of cancellous bone of avascular necrosis of femoral heads

NASA Astrophysics Data System (ADS)

Yao, Xuefeng; Wang, Peng; Dai, Ruchun; Yeh, Hsien Yang

2010-03-01

The aim of this study is to investigate microscopic structure and characterize cancellous bone of avascular necrosis of the femoral head (ANFH). The rabbit model of the ANFH is established. The histopathologic features are studied successfully. The differences between the steroid-injection group (S.G.) and the controlled group (C.G.) are examined, including the weight of rabbits, the hematological examination and the three-dimensional structures. It is found that the plasma levels of cholesterol (CHO), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) in S.G. are lower than those in C.G. when the triglyceride (TG) increased in the S.G.; but the bone mineral content (BMC) and the structural model index (SMI) of the organ and tissue decreased significantly in S.G. Three-dimensional structures of the femoral head are obtained using micro-computed tomography (CT) scanning and the mechanical model is established to analyze the influences of these structural changes on the mechanical properties of the cancellous bone.

A comparison of classical histology to anatomy revealed by hard x-rays

NASA Astrophysics Data System (ADS)

Richter, Claus-Peter; Tan, Xiaodong; Young, Hunter; Stock, Stuart; Robinson, Alan; Byskosh, Orest; Zheng, Jing; Soriano, Carmen; Xiao, Xianghui; Whitlon, Donna

2016-10-01

Many diseases trigger morphological changes in affected tissue. Today, classical histology is still the "gold standard" used to study and describe those changes. Classical histology, however, is time consuming and requires chemical tissue manipulations that can result in significant tissue distortions. It is sometimes difficult to separate tissue-processing artifacts from changes caused by the disease process. We show that synchrotron X-ray phase-contrast micro-computed tomography (micro-CT) can be used to examine non-embedded, hydrated tissue at a resolution comparable to that obtained with classical histology. The data analysis from stacks of reconstructed micro-CT images is more flexible and faster than when using the classical, physically embedded sections that are by necessity fixed in a particular orientation. We show that in a three-dimensional (3D) structure with meticulous structural details such as the cochlea and the kidney, micro-CT is more flexible, faster and more convenient for morphological studies and disease diagnoses.

PULSED FOCUSED ULTRASOUND TREATMENT OF MUSCLE MITIGATES PARALYSIS-INDUCED BONE LOSS IN THE ADJACENT BONE: A STUDY IN A MOUSE MODEL

PubMed Central

Poliachik, Sandra L.; Khokhlova, Tatiana D.; Wang, Yak-Nam; Simon, Julianna C.; Bailey, Michael R.

2015-01-01

Bone loss can result from bed rest, space flight, spinal cord injury or age-related hormonal changes. Current bone loss mitigation techniques include pharmaceutical interventions, exercise, pulsed ultrasound targeted to bone and whole body vibration. In this study, we attempted to mitigate paralysis-induced bone loss by applying focused ultrasound to the midbelly of a paralyzed muscle. We employed a mouse model of disuse that uses onabotulinumtoxinA-induced paralysis, which causes rapid bone loss in 5 d. A focused 2 MHz transducer applied pulsed exposures with pulse repetition frequency mimicking that of motor neuron firing during walking (80 Hz), standing (20 Hz), or the standard pulsed ultrasound frequency used in fracture healing (1 kHz). Exposures were applied daily to calf muscle for 4 consecutive d. Trabecular bone changes were characterized using micro-computed tomography. Our results indicated that application of certain focused pulsed ultrasound parameters was able to mitigate some of the paralysis-induced bone loss. PMID:24857416

Investigation of span-chordwise bending anisotropy of honeybee forewings

PubMed Central

Ning, JianGuo; Ma, Yun; Zhang, PengFei

2017-01-01

ABSTRACT In this study, the spanwise and chordwise bending stiffness EI of honeybee forewings were measured by a cantilevered bending test. The test results indicate that the spanwise EI of the forewing is two orders of magnitude larger than the chordwise EI. Three structural aspects result in this span-chordwise bending anisotropy: the distribution of resilin patches, the corrugation along the span and the leading edge vein of the venation. It was found that flexion lines formed by resilin patches revealed through fluorescence microscopy promoted the chordwise bending of the forewing during flapping flight. Furthermore, the corrugation of the wing and leading edge veins of the venation, revealed by micro-computed tomography, determines the relatively greater spanwise EI of the forewing. The span-chordwise anisotropy exerts positive structural and aerodynamic influences on the wing. In summary, this study potentially assists researchers in understanding the bending characteristics of insect wings and might be an important reference for the design and manufacture of bio-inspired wings for flapping micro aerial vehicles. PMID:28396486

Custom-made composite scaffolds for segmental defect repair in long bones.

PubMed

Reichert, Johannes C; Wullschleger, Martin E; Cipitria, Amaia; Lienau, Jasmin; Cheng, Tan K; Schütz, Michael A; Duda, Georg N; Nöth, Ulrich; Eulert, Jochen; Hutmacher, Dietmar W

2011-08-01

Current approaches for segmental bone defect reconstruction are restricted to autografts and allografts which possess osteoconductive, osteoinductive and osteogenic properties, but face significant disadvantages. The objective of this study was to compare the regenerative potential of scaffolds with different material composition but similar mechanical properties to autologous bone graft from the iliac crest in an ovine segmental defect model. After 12 weeks, in vivo specimens were analysed by X-ray imaging, torsion testing, micro-computed tomography and histology to assess amount, strength and structure of the newly formed bone. The highest amounts of bone neoformation with highest torsional moment values were observed in the autograft group and the lowest in the medical grade polycaprolactone and tricalcium phosphate composite group. The study results suggest that scaffolds based on aliphatic polyesters and ceramics, which are considered biologically inactive materials, induce only limited new bone formation but could be an equivalent alternative to autologous bone when combined with a biologically active stimulus such as bone morphogenetic proteins.

Analyzing nature's protective design: The glyptodont body armor.

PubMed

du Plessis, Anton; Broeckhoven, Chris; Yadroitsev, Igor; Yadroitsava, Ina; le Roux, Stephan Gerhard

2018-06-01

Many animal species evolved some form of body armor, such as scales of fish and bony plates or osteoderms of reptiles. Although a protective function is often taken for granted, recent studies show that body armor might comprise multiple functionalities and is shaped by trade-offs among these functionalities. Hence, despite the fact that natural body armor might serve as bio-inspiration for the development of artificial protective materials, focussing on model systems in which body armor serves a solely protective function might be pivotal. In this study, we investigate the osteoderms of Glyptotherium arizonae, an extinct armadillo-like mammal in which body armor evolved as protection against predators and/or tail club blows of conspecifics. By using a combination of micro-computed tomography, reverse-engineering, stress simulations and mechanical testing of 3D printed models, we show that the combination of dense compact layers and porous lattice core might provide an optimized combination of strength and high energy absorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

Impaired bone formation in ovariectomized mice reduces implant integration as indicated by longitudinal in vivo micro-computed tomography.

PubMed

Li, Zihui; Kuhn, Gisela; Schirmer, Michael; Müller, Ralph; Ruffoni, Davide

2017-01-01

Although osteoporotic bone, with low bone mass and deteriorated bone architecture, provides a less favorable mechanical environment than healthy bone for implant fixation, there is no general agreement on the impact of osteoporosis on peri-implant bone (re)modeling, which is ultimately responsible for the long term stability of the bone-implant system. Here, we inserted an implant in a mouse model mimicking estrogen deficiency-induced bone loss and we monitored with longitudinal in vivo micro-computed tomography the spatio-temporal changes in bone (re)modeling and architecture, considering the separate contributions of trabecular, endocortical and periosteal surfaces. Specifically, 12 week-old C57BL/6J mice underwent OVX/SHM surgery; 9 weeks after we inserted special metal-ceramics implants into the 6th caudal vertebra and we measured bone response with in vivo micro-CT weekly for the following 6 weeks. Our results indicated that ovariectomized mice showed a reduced ability to increase the thickness of the cortical shell close to the implant because of impaired peri-implant bone formation, especially at the periosteal surface. Moreover, we observed that healthy mice had a significantly higher loss of trabecular bone far from the implant than estrogen depleted animals. Such behavior suggests that, in healthy mice, the substantial increase in peri-implant bone formation which rapidly thickened the cortex to secure the implant may raise bone resorption elsewhere and, specifically, in the trabecular network of the same bone but far from the implant. Considering the already deteriorated bone structure of estrogen depleted mice, further bone loss seemed to be hindered. The obtained knowledge on the dynamic response of diseased bone following implant insertion should provide useful guidelines to develop advanced treatments for osteoporotic fracture fixation based on local and selective manipulation of bone turnover in the peri-implant region.

Impaired bone formation in ovariectomized mice reduces implant integration as indicated by longitudinal in vivo micro-computed tomography

PubMed Central

Li, Zihui; Kuhn, Gisela; Schirmer, Michael; Müller, Ralph

2017-01-01

Although osteoporotic bone, with low bone mass and deteriorated bone architecture, provides a less favorable mechanical environment than healthy bone for implant fixation, there is no general agreement on the impact of osteoporosis on peri-implant bone (re)modeling, which is ultimately responsible for the long term stability of the bone-implant system. Here, we inserted an implant in a mouse model mimicking estrogen deficiency-induced bone loss and we monitored with longitudinal in vivo micro-computed tomography the spatio-temporal changes in bone (re)modeling and architecture, considering the separate contributions of trabecular, endocortical and periosteal surfaces. Specifically, 12 week-old C57BL/6J mice underwent OVX/SHM surgery; 9 weeks after we inserted special metal-ceramics implants into the 6th caudal vertebra and we measured bone response with in vivo micro-CT weekly for the following 6 weeks. Our results indicated that ovariectomized mice showed a reduced ability to increase the thickness of the cortical shell close to the implant because of impaired peri-implant bone formation, especially at the periosteal surface. Moreover, we observed that healthy mice had a significantly higher loss of trabecular bone far from the implant than estrogen depleted animals. Such behavior suggests that, in healthy mice, the substantial increase in peri-implant bone formation which rapidly thickened the cortex to secure the implant may raise bone resorption elsewhere and, specifically, in the trabecular network of the same bone but far from the implant. Considering the already deteriorated bone structure of estrogen depleted mice, further bone loss seemed to be hindered. The obtained knowledge on the dynamic response of diseased bone following implant insertion should provide useful guidelines to develop advanced treatments for osteoporotic fracture fixation based on local and selective manipulation of bone turnover in the peri-implant region. PMID:28910363

Periodontitis contributes to aberrant metabolism in type 2 diabetes mellitus rats by stimulating the expression of adipokines.

PubMed

Luo, S; Yang, X; Wang, D; Ni, J; Wu, J; Xu, Z; Xuan, D; Zhang, J

2016-08-01

Periodontitis has been associated with type 2 diabetes mellitus. We investigated the effects of local aberrant secretion of adipokines in diabetic rats on systemic metabolism. Otsuka Long-Evans Tokushima Fatty (OLETF) and non-diabetic Long-Evans Tokushima Otsuka rats were used as a diabetic model and associated control, respectively. Periodontitis was induced using a silk ligature for 36 wk. Rats were grouped into OLETF with (OP+) or without (OP-) periodontitis and Long-Evans Tokushima Otsuka with (LP+) or without (LP-) periodontitis. Alveolar bone resorption and destruction were evaluated by micro-computed tomography and hematoxylin and eosin staining. After 20 wk of periodontitis induction, lipids, insulin, interleukin-1, leptin and plasminogen activator inhibitor-1 were analyzed, and mRNA expressions of NF-κB, Mark8, TLR2 and -4, IKBKB and Nampt were evaluated by quantitative polymerase chain reaction in adipose tissue. After ligation, OLETF rats exhibited typical periodontitis lesions with the clinical features of type 2 diabetes mellitus. When compared with the OP(-) group, the area under curve of the oral glucose tolerance test and homeostatic model assessment-insulin resistance values were significantly higher in the OP(+) group. Micro-computed tomography showed that the OP(+) group had more bone resorption than the OP(-) group. When compared with the OP(-) group, the OP(+) group also exhibited higher total cholesterol (p < 0.05), leptin (p < 0.05), insulin (p > 0.05) and higher expression of Nampt (p < 0.05) and IKBKB (p < 0.05). The LP(+) group had a trend towards higher bone resorption when compared with the LP(-) group. Additionally, no difference in white adipose tissues or adipokines was found between LP(+) and LP(-) rats. Chronic periodontitis can alter lipid profiles in affected rats, elevate adipose tissue expression of Nampt and affect the metabolism of adipose tissue through the NF-κB pathway to inflame diabetes. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Applications of Microcomputers in Patient Care

PubMed Central

Eden, Henry S.

1979-01-01

This paper serves as an introduction to two sessions on microcomputer applications in patient care. It describes several advantages offered by microcomputers in the design of medical devices--flexibility, reliability, smallness, and low power consumption. It concludes by discussing eight categories of microcomputer application.

Comparison of Gap Volume after Retrofilling Using 4 Different Filling Materials: Evaluation by Micro-computed Tomography.

PubMed

Kim, Sue Youn; Kim, Hyeon-Cheol; Shin, Su-Jung; Kim, Euiseong

2018-04-01

The purpose of this study was to evaluate the gap volume between dentin and root-end filling materials. Four root-end filling materials were compared in the present study: ProRoot MTA (PRM; Dentsply Tulsa Dental, Tulsa, OK), MTA Angelus (MAG; Angelus, Londrina, Brazil), EndoCem MTA (ECM; Maruchi, Wonju, Korea), and RetroMTA (RTM; BioMTA, Seoul, Korea). Forty-eight single-rooted, extracted human teeth were instrumented with nickel-titanium instruments and oburated with gutta-percha. The apical 3 mm of the root tip was resected, and root-end preparation was performed with a diamond bur. The root-end cavity was filled with the experimental filling materials for the 4 designated groups (n = 10). Then, the samples were scanned with micro-computed tomographic (micro-CT) imaging. Three-dimensional images of the samples were reconstructed, and the volume of the gap between the tooth surface (dentinal wall) and the root-end filling materials was measured. The percentage volume of the gap between the tooth structure and the root-end filling material (V G %) was calculated. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests at a significance level of 95%. The median V G % values for the PRM, MAG, ECM, and RTM groups were 0.00472, 0.00134, 0.00014, and 0.00071, respectively. The ProRoot MTA group showed the greatest gap volume percentage among the experimental groups with a significant statistical difference (P < .05). From the micro-CT analysis, ProRoot MTA had a greater gap volume percentage than other root-end filling materials. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Computed tomography-based tissue-engineered scaffolds in craniomaxillofacial surgery.

PubMed

Smith, M H; Flanagan, C L; Kemppainen, J M; Sack, J A; Chung, H; Das, S; Hollister, S J; Feinberg, S E

2007-09-01

Tissue engineering provides an alternative modality allowing for decreased morbidity of donor site grafting and decreased rejection of less compatible alloplastic tissues. Using image-based design and computer software, a precisely sized and shaped scaffold for osseous tissue regeneration can be created via selective laser sintering. Polycaprolactone has been used to create a condylar ramus unit (CRU) scaffold for application in temporomandibular joint reconstruction in a Yucatan minipig animal model. Following sacrifice, micro-computed tomography and histology was used to demonstrate the efficacy of this particular scaffold design. A proof-of-concept surgery has demonstrated cartilaginous tissue regeneration along the articulating surface with exuberant osseous tissue formation. Bone volumes and tissue mineral density at both the 1 and 3 month time points demonstrated significant new bone growth interior and exterior to the scaffold. Computationally designed scaffolds can support masticatory function in a large animal model as well as both osseous and cartilage regeneration. Our group is continuing to evaluate multiple implant designs in both young and mature Yucatan minipig animals. 2007 John Wiley & Sons, Ltd.

Multi-scale analytical investigation of fly ash in concrete

NASA Astrophysics Data System (ADS)

Aboustait, Mohammed B.

Much research has been conducted to find an acceptable concrete ingredient that would act as cement replacement. One promising material is fly ash. Fly ash is a by-product from coal-fired power plants. Throughout this document work on the characterization of fly ash structure and composition will be explored. This effort was conducted through a mixture of cutting edge multi-scale analytical X-ray based techniques that use both bulk experimentation and nano/micro analytical techniques. Furtherly, this examination was coupled by performing Physical/Mechanical ASTM based testing on fly ash-enrolled-concrete to examine the effects of fly ash introduction. The most exotic of the cutting edge characterization techniques endorsed in this work uses the Nano-Computed Tomography and the Nano X-ray Fluorescence at Argonne National Laboratory to investigate single fly ash particles. Additional Work on individual fly ash particles was completed by laboratory-based Micro-Computed Tomography and Scanning Electron Microscopy. By combining the results of individual particles and bulk property tests, a compiled perspective is introduced, and accessed to try and make new insights into the reactivity of fly ash within concrete.

Microcomputer Applications in Agriculture.

ERIC Educational Resources Information Center

Hilgenberg, Gene; And Others

This curriculum guide is intended to assist persons teaching a course in microcomputer applications in agriculture. (These applications are designed to be used on Apple IIe or TRS-80 microcomputers.) Addressed in the individual units of instruction are the following topics: microcomputer operating procedures; procedures for evaluating and…

Microcomputer Usage in Secondary Marketing Education. A National Study.

ERIC Educational Resources Information Center

Searle, A. Gary

A study was conducted to determine microcomputer hardware, software, and inservice components of secondary marketing education programs. A questionnaire was developed and sent to 420 teacher-coordinators in 42 states. A total of 225 (54 percent) usable returns were tabulated at the University of Wisconsin-Stout Computer Center. Results of the…

A micro-computed tomographic study of band-shaped root canal isthmuses, having their floor in the apical third of mesial roots of mandibular first molars.

PubMed

Keleş, A; Keskin, C

2018-02-01

To conduct a quantitative and qualitative analysis of the band-shaped isthmus area, the floor of which was in the apical third in the mesial roots of mandibular first molars using micro-computed tomography (micro-CT). Micro-CT images of 269 mesial roots of mandibular first molars were evaluated, and 40 specimens with a band-shaped isthmus, with a floor in the apical third, were selected. The major diameter, minor diameter, roundness, area and perimeter values for the most coronal and apical slices where the isthmus was visible were measured. The distances between these slices were measured as the isthmus length, and the total volume, structure model index and surface area of the isthmus were measured. The distances between the isthmus floor and two apical foramina and the number of root canal orifices were calculated. The dimensions of the isthmus roof and the floor were compared, and the data were analysed using descriptive statistics and Student's t-tests with a significance threshold set at 5%. A total of 15% of the specimens had band-shaped isthmuses with a floor in the apical third. The isthmus roof exhibited significantly greater major and minor diameter values compared to the isthmus floor (P < 0.05). No significant difference was detected between the isthmus roof and the floor with regard to roundness (P > 0.05). Three- and two-dimensional analyses of the mesial roots of mandibular molars revealed that band-shaped isthmuses had complex shapes. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

The Application of Contrast Media for In Vivo Feature Enhancement in X-Ray Computed Tomography of Soil-Grown Plant Roots.

PubMed

Keyes, Samuel D; Gostling, Neil J; Cheung, Jessica H; Roose, Tiina; Sinclair, Ian; Marchant, Alan

2017-06-01

The use of in vivo X-ray microcomputed tomography (μCT) to study plant root systems has become routine, but is often hampered by poor contrast between roots, soil, soil water, and soil organic matter. In clinical radiology, imaging of poorly contrasting regions is frequently aided by the use of radio-opaque contrast media. In this study, we present evidence for the utility of iodinated contrast media (ICM) in the study of plant root systems using μCT. Different dilutions of an ionic and nonionic ICM (Gastrografin 370 and Niopam 300) were perfused into the aerial vasculature of juvenile pea plants via a leaf flap (Pisum sativum). The root systems were imaged via μCT, and a variety of image-processing approaches used to quantify and compare the magnitude of the contrast enhancement between different regions. Though the treatment did not appear to significantly aid extraction of full root system architectures from the surrounding soil, it did allow the xylem and phloem units of seminal roots and the vascular morphology within rhizobial nodules to be clearly visualized. The nonionic, low-osmolality contrast agent Niopam appeared to be well tolerated by the plant, whereas Gastrografin showed evidence of toxicity. In summary, the use of iodine-based contrast media allows usually poorly contrasting root structures to be visualized nondestructively using X-ray μCT. In particular, the vascular structures of roots and rhizobial nodules can be clearly visualized in situ.

On Selecting a Microcomputer for 1800 Freshmen at Drexel.

ERIC Educational Resources Information Center

Smith, Allan L.; And Others

1984-01-01

Presents report to Vice President for Academic Affairs of Drexel University which formed the basis for negotiating an agreement with Apple Corporation to provide required microcomputers for incoming freshmen. Microcomputer Selection Committee constitution and charge, student ownership goals, requirements and specifications for the microcomputers,…

Refinery spreadsheet highlights microcomputer process applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tucker, M.A.

1984-01-23

Microcomputer applications in the process areas at Chevron U.S.A. refineries and at the Chevron Research Co. illustrate how the microcomputer has changed the way we do our jobs. This article will describe major uses of the microcomputer as a personal work tool in Chevron process areas. It will also describe how and why many of Chevron's microcomputer applications were developed and their characteristics. One of our earliest microcomputer applications, developed in late 1981, was an electronic spreadsheet program using a small desktop microcomputer. It was designed to help a refinery planner prepare monthly plans for a small portion of onemore » of our major refineries. This particular microcomputer had a tiny 4-in. screen, and the reports were several strips of print-out from the microcomputer's 3-in.-wide internal printer taped together. In spite of these archaic computing conditions, it was a successful application. It automated what had been very tedious and time-consuming calculations with a pencil, a calculator, and a great deal of erasing. It eliminated filling out large ''horseblanket'' reports. The electronic spreadsheet was also flexible; the planner could easily change the worksheet to match new operating constraints, new process conditions, and new feeds and products. Fortunately, within just a few months, this application graduated to a similar electronic spreadsheet program on a new, more powerful microcomputer. It had a bigger display screen and a letter-size printer. The same application is still in use today, although it has been greatly enhanced and altered to match extensive plant modifications. And there are plans to expand it again onto yet another, more powerful microcomputer.« less

Tools for Scientific Thinking: Microcomputer-Based Laboratories for the Naive Science Learner.

ERIC Educational Resources Information Center

Thornton, Ronald K.

A promising new development in science education is the use of microcomputer-based laboratory tools that allow for student-directed data acquisition, display, and analysis. Microcomputer-based laboratories (MBL) make use of inexpensive microcomputer-connected probes to measure such physical quantities as temperature, position, and various…

The Power of the New Microcomputers: Challenge and Opportunity.

ERIC Educational Resources Information Center

Rumsey, Eric

1990-01-01

Describes current developments in microcomputer technology, including CD-ROM, the 80386 microprocessor, and the graphic user interface. It is argued that, as the information handling capacity of microcomputers increases, the microcomputer industry will increasingly market information to end users, and the library will be challenged to provide the…

Installing a Microcomputer Lab in a Medium-Sized Academic Library.

ERIC Educational Resources Information Center

Hallman, Clark N.; And Others

Designed to serve as a blueprint for other libraries developing plans for microcomputer facilities, this report describes the planning and implementation of a microcomputer laboratory at South Dakota State University's Hilton M. Briggs Library. The university's plan for installing microcomputer labs on campus and the initial planning process…

TLC for Growing Minds. Microcomputer Projects. Elementary Intermediate Microcomputer Projects.

ERIC Educational Resources Information Center

Buxton, Marilyn

Designed to improve students' thinking, learning, and creative skills while they learn to program a microcomputer in BASIC programing language, this book for intermediate learners at the elementary school level provides a variety of microcomputer activities designed to extend the concepts learned in accompanying instructional manuals (Volumes 3…

Study of Issues Related to the Implementation of Computer Technology in Schools. Final Report, July, 1981. Technical Report No. 2.

ERIC Educational Resources Information Center

Sheingold, Karen; And Others

This study examined ways in which microcomputers are used in schools and the complex issues that surround their implementation. Three fictional geographically distinct school districts with a diversity of microcomputer applications at both the elementary and secondary levels were studied: Salerno, a large southern city; Granite, a midwestern city;…

NLM microcomputer-based tutorials (for microcomputers). Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perkins, M.

1990-04-01

The package consists of TOXLEARN--a microcomputer-based training package for TOXLINE (Toxicology Information Online), CHEMLEARN-a microcomputer-based training package for CHEMLINE (Chemical Information Online), MEDTUTOR--a microcomputer-based training package for MEDLINE (Medical Information Online), and ELHILL LEARN--a microcomputer-based training package for the ELHILL search and retrieval software that supports the above-mentioned databases...Software Description: The programs were developed under PILOTplus using the NLM LEARN Programmer. They run on IBM-PC, XT, AT, PS/2, and fully compatible computers. The programs require 512K RAM memory, one disk drive, and DOS 2.0 or higher. The software supports most monochrome, color graphics, enhanced color graphics, or visual graphics displays.

Microcomputers on Campus.

ERIC Educational Resources Information Center

Schimizzi, Ned V.; Dudley, Donald

The study reports on a nationwide survey that investigated the specific planning steps and procedures used by colleges and universities in implementing microcomputer instruction into their teacher education curriculum. The findings presented are based on 101 usable responses to a 55-item questionnaire mailed to five major college and university…

A microcomputer model for simulating pressurized flow in a storm sewer system : interim report.

DOT National Transportation Integrated Search

1988-01-01

A study is being conducted on the development of a microcomputer model for simulating storm sewer flow under surcharged or pressurized conditions. Several existing models, including the EPA Storm Water Management Hodel (SYMM) and the Illinois Urban D...

Non-Destructive Characterization of UO2+x Nuclear Fuels

DOE PAGES

Pokharel, Reeju; Brown, Donald W.; Clausen, Bjørn; ...

2017-10-27

This article describes the effect of fabrication conditions on as-sintered microstructures of various stoichiometric ratios of uranium dioxide, UO 2+x, with the aim of enhancing the understanding of fabrication process and developing and validating a predictive microstructurebased model for fuel performance. We demonstrate the ability of novel, non-destructive methods such as near-field high-energy X-ray diffraction microscopy (nf-HEDM) and micro-computed tomography (μ-CT) to probe bulk samples of high-Z materials by non-destructively characterizing three samples: UO 2.00, UO 2.11, and UO 2.16, which were sintered at 1450°C for 4 hours. The measured 3D microstructures revealed that grain size and porosity were influencedmore » by deviation from stoichiometry.« less

Novel application and serial evaluation of tissue-engineered portal vein grafts in a murine model.

PubMed

Maxfield, Mark W; Stacy, Mitchel R; Kurobe, Hirotsugu; Tara, Shuhei; Yi, Tai; Cleary, Muriel A; Zhuang, Zhen W; Rodriguez-Davalos, Manuel I; Emre, Sukru H; Iwakiri, Yasuko; Shinoka, Toshiharu; Breuer, Christopher K

2017-12-01

Surgical management of pediatric extrahepatic portal vein obstruction requires meso-Rex bypass using autologous or synthetic grafts. Tissue-engineered vascular grafts (TEVGs) provide an alternative, but no validated animal models using portal TEVGs exist. Herein, we preclinically assess TEVGs as portal vein bypass grafts. TEVGs were implanted as portal vein interposition conduits in SCID-beige mice, monitored by ultrasound and micro-computed tomography, and histologically assessed postmortem at 12 months. TEVGs remained patent for 12 months. Histologic analysis demonstrated formation of neovessels that resembled native portal veins, with similar content of smooth muscle cells, collagen type III and elastin. TEVGs are feasible portal vein conduits in a murine model. Further preclinical evaluation of TEVGs may facilitate pediatric clinical translation.

Development of High-Speed Fluorescent X-Ray Micro-Computed Tomography

NASA Astrophysics Data System (ADS)

Takeda, T.; Tsuchiya, Y.; Kuroe, T.; Zeniya, T.; Wu, J.; Lwin, Thet-Thet; Yashiro, T.; Yuasa, T.; Hyodo, K.; Matsumura, K.; Dilmanian, F. A.; Itai, Y.; Akatsuka, T.

2004-05-01

A high-speed fluorescent x-ray CT (FXCT) system using monochromatic synchrotron x rays was developed to detect very low concentration of medium-Z elements for biomedical use. The system is equipped two types of high purity germanium detectors, and fast electronics and software. Preliminary images of a 10mm diameter plastic phantom containing channels field with iodine solutions of different concentrations showed a minimum detection level of 0.002 mg I/ml at an in-plane spatial resolution of 100μm. Furthermore, the acquisition time was reduced about 1/2 comparing to previous system. The results indicate that FXCT is a highly sensitive imaging modality capable of detecting very low concentration of iodine, and that the method has potential in biomedical applications.

Trench fast reactor design using the microcomputer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rohach, A.F.; Sankoorikal, J.T.; Schmidt, R.R.

1987-01-01

This project is a study of alternative liquid-metal-cooled fast power reactor system concepts. Specifically, an unconventional primary system is being conceptually designed and evaluated. The project design is based primarily on microcomputer analysis through the use of computational modules. The reactor system concept is a long, narrow pool with a long, narrow reactor called a trench-type pool reactor in it. The reactor consists of five core-blanket modules in a line. Specific power is to be modest, permitting long fuel residence time. Two fuel cycles are currently being considered. The reactor design philosophy is that of the inherently safe concept. Thismore » requires transient analysis dependent on reactivity coefficients: prompt fuel, including Doppler and expansion, fuel expansion, sodium temperature and void, and core expansion. Conceptual reactor design is done on a microcomputer. A part of the trench reactor project is to develop a microcomputer-based system that can be used by the user for scoping studies and design. Current development includes the neutronics and fuel management aspects of the design. Thermal-hydraulic analysis and economics are currently being incorporated into the microcomputer system. The system is menu-driven including preparation of program input data and of output data for displays in graphics form.« less

Feasibility Study on the Application of Microcomputers to Library and Information Work at SEAMEO-BIOTROP.

ERIC Educational Resources Information Center

Haravu, L. J.

The result of a two-week consultant mission to the South East Asian Ministers of Education Organization (SEAMEO) at Bogor, Indonesia, this study explored the feasibility of applying microcomputers to library and information work in the Clearing House for Information Division of BIOTROP, which has a regional responsibility for the collection,…

Nondestructive Evaluation (NDE) for Characterizing Oxidation Damage in Cracked Reinforced Carbon-Carbon

NASA Technical Reports Server (NTRS)

Roth, Don J.; Jacobson, Nathan S.; Rauser, Richard W.; Wincheski, Russell A.; Walker, James L.; Cosgriff, Laura A.

2010-01-01

In this study, coated reinforced carbon-carbon (RCC) samples of similar structure and composition as that from the NASA space shuttle orbiter's thermal protection system were fabricated with slots in their coating simulating craze cracks. These specimens were used to study oxidation damage detection and characterization using nondestructive evaluation (NDE) methods. These specimens were heat treated in air at 1143 C and 1200 C to create cavities in the carbon substrate underneath the coating as oxygen reacted with the carbon and resulted in its consumption. The cavities varied in diameter from approximately 1 to 3mm. Single-sided NDE methods were used because they might be practical for on-wing inspection, while X-ray micro-computed tomography (CT) was used to measure cavity sizes in order to validate oxidation models under development for carbon-carbon materials. An RCC sample having a naturally cracked coating and subsequent oxidation damage was also studied with X-ray micro-CT. This effort is a follow-on study to one that characterized NDE methods for assessing oxidation damage in an RCC sample with drilled holes in the coating.

Nondestructive Evaluation (NDE) for Characterizing Oxidation Damage in Cracked Reinforced Carbon-Carbon (RCC)

NASA Technical Reports Server (NTRS)

Roth, Don J.; Rauser, Richard W.; Jacobson, Nathan S.; Wincheski, Russell A.; Walker, James L.; Cosgriff, Laura A.

2009-01-01

In this study, coated reinforced carbon-carbon (RCC) samples of similar structure and composition as that from the NASA space shuttle orbiter's thermal protection system were fabricated with slots in their coating simulating craze cracks. These specimens were used to study oxidation damage detection and characterization using nondestructive evaluation (NDE) methods. These specimens were heat treated in air at 1143 and 1200 C to create cavities in the carbon substrate underneath the coating as oxygen reacted with the carbon and resulted in its consumption. The cavities varied in diameter from approximately 1 to 3 mm. Single-sided NDE methods were used since they might be practical for on-wing inspection, while x-ray micro-computed tomography (CT) was used to measure cavity sizes in order to validate oxidation models under development for carbon-carbon materials. An RCC sample having a naturally-cracked coating and subsequent oxidation damage was also studied with x-ray micro-CT. This effort is a follow-on study to one that characterized NDE methods for assessing oxidation damage in an RCC sample with drilled holes in the coating.

Exceptional Children and Microcomputers, A Survey of Public School Applications.

ERIC Educational Resources Information Center

Crowner, T. Timothy

Telephone interviews on the use of microcomputers in special education were administered to personnel in 25 districts (drawn from a random sample of the largest school districts in the United States) on the following topics: coordination of microcomputers; numbers of microcomputers owned and used; pragmatic uses; funding; brands used; selection,…

Fabricating a Microcomputer on a Single Silicon Wafer

NASA Technical Reports Server (NTRS)

Evanchuk, V. L.

1983-01-01

Concept for "microcomputer on a slice" reduces microcomputer costs by eliminating scribing, wiring, and packaging of individual circuit chips. Low-cost microcomputer on silicon slice contains redundant components. All components-central processing unit, input/output circuitry, read-only memory, and random-access memory (CPU, I/O, ROM, and RAM) on placed on single silicon wafer.

TLC for Growing Minds. Microcomputer Projects. Adult Intermediate Microcomputer Projects.

ERIC Educational Resources Information Center

Taitt, Henry A.

Designed to improve students' thinking, learning, and creative skills while they learn to program a microcomputer in BASIC programing language, this book for intermediate learners at the high school/adult level provides a variety of microcomputer activities designed to extend the concepts taught in the accompanying instructional manuals (Volumes 3…

Microcomputers in American Public Schools: A National Survey.

ERIC Educational Resources Information Center

Ingersoll, Gary M.; And Others

1983-01-01

In the 1981-82 school year, microcomputers were located in one-third of United States schools. The dominant share for school-based microcomputers was held by Apple Computer followed by Tandy-Radio Shack and Commodore, but this was regionally related. The majority of teachers polled possess positive attitudes toward classroom use of microcomputers.…

A Low Cost Microcomputer Laboratory for Investigating Computer Architecture.

ERIC Educational Resources Information Center

Mitchell, Eugene E., Ed.

1980-01-01

Described is a microcomputer laboratory at the United States Military Academy at West Point, New York, which provides easy access to non-volatile memory and a single input/output file system for 16 microcomputer laboratory positions. A microcomputer network that has a centralized data base is implemented using the concepts of computer network…

[The study of DSX-I type microcomputer autometic control injector system].

PubMed

Shi, M; Wu, G; Bai, G; Xue, J; Zhang, Y

1997-01-01

This paper studies the propulsive force of injector system controlled by 8031 single-chip microcomputer for Medical use By using one 8031 single-chip microcomputer as a microprocessor, the minimal autometic control system is constructed, which turns real-time control into reality. This product is a modern appliance used in diagnostic imaging medicine, in design of which the advanced instrument and electrical machinery are integrated into a unified structure. The clinic data demonstrate that the contrast medium can be injected to patients with rapidly and evenly. Dynamic CT Scanning can be intensified at any site of the body. x-ray dose exposed and lobour intensity to the operator can be decreased greatly, raise working efficiency.

Application of X-ray phase contrast micro-tomography to the identification of traditional Chinese medicines

NASA Astrophysics Data System (ADS)

Ye, L. L.; Xue, Y. L.; Ni, L. H.; Tan, H.; Wang, Y. D.; Xiao, T. Q.

2013-07-01

Nondestructive and in situ investigation to the characteristic microstructures are important to the identification of traditional Chinese medicines (TCMs), especially for precious specimens and samples with oil contains. X-ray phase contrast micro-tomography (XPCMT) could be a practical solution for this kind of investigation. Fructus Foeniculi, a fruit kind of TCMs, is selected as the test sample. Experimental results show that the characteristic microstructures of Fructus Foeniculi, including vittae, vascular bundles, embryo, endosperm and the mesocarp reticulate cells around the vittae can be clearly distinguished and the integrated dissepiments microstructure in the vittae was observed successfully. Especially, for the first time, with virtual slice technique, it can investigate the liquid contains inside the TCMs. The results show that the vittae filled with volatile oil in the oil chamber were observed with this nondestructive and in situ 3-dimensional imaging technique. Furthermore, taking the advantage of micro-computed tomography, we can obtain the characteristic microstructures' quantitative information of the volume in liquid state. The volume of the oil chambers and the volatile oil, which are contained inside the vittae, was quantitatively analyzed. Accordingly, it can calculate the volume ratio of the volatile oil easily and accurately. As a result, we could conclude that XPCMT could be a useful tool for the nondestructive identification and quantitative analysis to TCMs.

Video Kills the Lecturing Star: New Technologies and the Teaching of Meterology.

ERIC Educational Resources Information Center

Sumner, Graham

1984-01-01

The educational potential of time-lapse video sequences and weather data obtained using a conventional microcomputer are considered in the light of recent advances in both fields. Illustrates how videos and microcomputers can be used to study clouds in meteorology classes. (RM)

Microcomputers and Continuing Motivation.

ERIC Educational Resources Information Center

Seymour, Sherrie L.; And Others

1987-01-01

Describes study that investigated the effects of medium of instructional practice, task difficulty, and gender on continuing motivation. Microcomputers and paper and pencil format were compared on tasks at a hard or easy difficulty level with fifth and sixth grade students, and questionnaires were used to determine student attitudes. (Author/LRW)

Methods of Microcomputer Research in Early Childhood Special Education.

ERIC Educational Resources Information Center

Fujiura, Glenn; Johnson, Lawrence J.

1986-01-01

The review of some recent studies on use of microcomputers in early childhood special education highlights methodological issues including the qualitative quantitative distinction and the interdependence of research design and interpretation. Imbedding qualitative methods into quasi- or true-experimental designs can provide more information than…

Model Experiment of Two-Dimentional Brownian Motion by Microcomputer.

ERIC Educational Resources Information Center

Mishima, Nobuhiko; And Others

1980-01-01

Describes the use of a microcomputer in studying a model experiment (Brownian particles colliding with thermal particles). A flow chart and program for the experiment are provided. Suggests that this experiment may foster a deepened understanding through mutual dialog between the student and computer. (SK)

Sentence Building with a Macintosh Microcomputer.

ERIC Educational Resources Information Center

Bennett, Ruth

A study using microcomputers for instruction in sentence-building skills with two groups of American Indians in bilingual education programs found computer-assisted instruction to be effective in developing differential skills in the different age groups. The method used small group activity at the computer, emphasizing the cooperative learning…

Evaluation of drug interaction microcomputer software: comparative study.

PubMed

Poirier, T I; Giudici, R

1991-01-01

Twelve drug interaction microcomputer software programs were evaluated and compared using general and specific criteria. This article summarizes and compares the features, ratings, advantages, and disadvantages of each program. Features of an ideal drug interaction program are noted. Recommended programs based on three price ranges are suggested.

Application of Minicomputers and Microcomputers to Information Handling.

ERIC Educational Resources Information Center

Griffiths, Jose-Marie

This study assesses the application of both minicomputers and microcomputers to information-handling procedures and makes recommendations for automating such procedures, particularly in developing nations. The report is based on a survey of existing uses of small computing equipment in libraries, archives, and information centers which was…

Satellite Doppler data processing using a microcomputer

NASA Technical Reports Server (NTRS)

Schmid, P. E.; Lynn, J. J.

1977-01-01

A microcomputer which was developed to compute ground radio beacon position locations using satellite measurements of Doppler frequency shift is described. Both the computational algorithms and the microcomputer hardware incorporating these algorithms were discussed. Results are presented where the microcomputer in conjunction with the NIMBUS-6 random access measurement system provides real time calculation of beacon latitude and longitude.

School Uses of Microcomputers: Reports from a National Survey. Issue No. 5.

ERIC Educational Resources Information Center

Johns Hopkins Univ., Baltimore, MD. Center for Social Organization of Schools.

School location of microcomputers and its impact on use were examined using data from the National Survey of School Uses of Microcomputers. An analysis of the responses from 1,082 (68% of the sample) microcomputer-using, public and non-public, elementary and secondary schools surveyed between December 1982 and March 1983, suggests that where…

User's guide to the LLL BASIC interpreter. [For 8080-based MCS-80 microcomputer system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allison, T.; Eckard, R.; Barber, J.

1977-06-09

Scientists are finding increased applications for microcomputers as process controllers in their experiments. However, while microcomputers are small and inexpensive, they are difficult to program in machine or assembly language. A high-level language is needed to enable scientists to develop their own microcomputer programs for their experiments on location. Recognizing this need, LLL contracted to have such a language developed. This report describes the result--the LLL BASIC interpreter, which operates with LLL's 8080-based MCS-80 microcomputer system. 4 tables.

Pilot of a System for Collecting Daily Classroom Data on Learning by Using Microcomputers.

ERIC Educational Resources Information Center

Mayer, Victor J.; Raudebaugh, William

This report describes a microcomputer system which collects data from students in classrooms on a daily basis and is then used to evaluate concept achievement and attitude changes through a time series analysis. Two pilot studies in two junior high schools in Ohio are detailed, where eighth grade students' progress in an earth science study unit…

A Curriculum for Preparing Science Teachers to Use Microcomputers.

ERIC Educational Resources Information Center

Ellis, James D.; Kuerbis, Paul J.

1991-01-01

ENLIST Micros, a project designed to improve quality and quantity of microcomputer use in science teaching, is described. Rationale and procedures behind its development; description of the pilot test model; results of the initial field test and an implementation study; description of the revised ENLIST Micros curriculum; and recommendations for…

A Faculty-Computer Nexus. Microcomputing Working Paper Series.

ERIC Educational Resources Information Center

McCord, Joan

The effects of the rapid introduction of computing in education on Drexel University faculty were studied. The university decided that incoming 1983 freshmen would be required to own microcomputers, which could be bought at reduced cost. A questionnaire was administered to determine faculty members' experience with computers, their values,…

The Evolution and Development of Cephalopod Chambers and Their Shape.

PubMed

Lemanis, Robert; Korn, Dieter; Zachow, Stefan; Rybacki, Erik; Hoffmann, René

2016-01-01

The Ammonoidea is a group of extinct cephalopods ideal to study evolution through deep time. The evolution of the planispiral shell and complexly folded septa in ammonoids has been thought to have increased the functional surface area of the chambers permitting enhanced metabolic functions such as: chamber emptying, rate of mineralization and increased growth rates throughout ontogeny. Using nano-computed tomography and synchrotron radiation based micro-computed tomography, we present the first study of ontogenetic changes in surface area to volume ratios in the phragmocone chambers of several phylogenetically distant ammonoids and extant cephalopods. Contrary to the initial hypothesis, ammonoids do not possess a persistently high relative chamber surface area. Instead, the functional surface area of the chambers is higher in earliest ontogeny when compared to Spirula spirula. The higher the functional surface area the quicker the potential emptying rate of the chamber; quicker chamber emptying rates would theoretically permit faster growth. This is supported by the persistently higher siphuncular surface area to chamber volume ratio we collected for the ammonite Amauroceras sp. compared to either S. spirula or nautilids. We demonstrate that the curvature of the surface of the chamber increases with greater septal complexity increasing the potential refilling rates. We further show a unique relationship between ammonoid chamber shape and size that does not exist in S. spirula or nautilids. This view of chamber function also has implications for the evolution of the internal shell of coleoids, relating this event to the decoupling of soft-body growth and shell growth.

Microcomputers in Florida Public Schools. Fall 1991. MIS Statistical Brief, Series 92-06B.

ERIC Educational Resources Information Center

Parks, Brenda; Bennett, Karen

This statistical brief on microcomputers in Florida public schools includes data on the following: (1) the number of instructional microcomputers from 1987-88 to 1991-92; (2) the number of instructional microcomputers for each school district from 1987-88 to 1991-92, including net change from 1990-91 to 1991-92; (3) percentages of instructional…

Microcomputers in Florida Public Schools. Fall 1990. MIS Statistical Brief, Series 91-07B.

ERIC Educational Resources Information Center

Florida State Dept. of Education, Tallahassee. Bureau of Program Support Services.

This summary of the use of microcomputers in Florida public schools during the 1990-91 school year indicates that the schools have reported a total of 131,367 microcomputers being used for student instruction, and 21,806 being used for administrative purposes. Four tables present data on the number of microcomputers in individual school districts…

Comparison of Apple, Epson, IBM, and Other Microcomputers for Applications in Rehabilitation Systems for Persons with Physical Handicaps. Revision D.

ERIC Educational Resources Information Center

Vanderheiden, Gregg C.

The paper analyzes major microcomputer systems and their use in rehabilitative systems for persons with physical handicaps. Four categories of microcomputers are addressed: systems designed for home or school with emphasis on low cost, recreation, and educational software; general purpose microcomputers with applications in a large number of…

A Method for Evaluation of Microcomputers for Tactical Applications.

DTIC Science & Technology

1980-06-01

application. The computational requirements of a tactical application are specified in terms of performance parameters. The presently marketed microcomputer...computational requirements of a tactical application are specified in terms of performance parameters. The presently marketed microcomputer and multi...also to provide a method to evaluate microcomputer systems for tactical applications, i.e., Command Control Communications (C 3), weapon systems, etc

Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic.

PubMed

He, Fupo; Ren, Weiwei; Tian, Xiumei; Liu, Wei; Wu, Shanghua; Chen, Xiaoming

2016-07-01

In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. Copyright © 2016 Elsevier B.V. All rights reserved.

Supercritical phase inversion of starch-poly(epsilon-caprolactone) for tissue engineering applications.

PubMed

Duarte, Ana Rita C; Mano, João F; Reis, Rui L

2010-02-01

In this work, a starch-based polymer, namely a blend of starch-poly(epsilon-caprolactone) was processed by supercritical assisted phase inversion process. This processing technique has been proposed for the development of 3D structures with potential applications in tissue engineering applications, as scaffolds. The use of carbon dioxide as non-solvent in the phase inversion process leads to the formation of a porous and interconnected structure, dry and free of any residual solvent. Different processing conditions such as pressure (from 80 up to 150 bar) and temperature (45 and 55 degrees C) were studied and the effect on the morphological features of the scaffolds was evaluated by scanning electron microscopy and micro-computed tomography. The mechanical properties of the SPCL scaffolds prepared were also studied. Additionally, in this work, the in vitro biological performance of the scaffolds was studied. Cell adhesion and morphology, viability and proliferation was assessed and the results suggest that the materials prepared are allow cell attachment and promote cell proliferation having thus potential to be used in some for biomedical applications.

Microcomputers and the future of epidemiology.

PubMed Central

Dean, A G

1994-01-01

The Workshop on Microcomputers and the Future of Epidemiology was held March 8-9, 1993, at the Turner Conference Center, Atlanta, GA, with 130 public health professionals participating. The purpose of the workshop was to define microcomputer needs in epidemiology and to propose future initiatives. Thirteen groups representing public health disciplines defined their needs for better and more useful data, development of computer technology appropriate to epidemiology, user support and human infrastructure development, and global communication and planning. Initiatives proposed were demonstration of health surveillance systems, new software and hardware, computer-based training, projects to establish or improve data bases and community access to data bases, improved international communication, conferences on microcomputer use in particular disciplines, a suggestion to encourage competition in the production of public-domain software, and longrange global planning for epidemiologic computing and data management. Other interested groups are urged to study, modify, and implement those ideas. PMID:7910692

A microcomputer network for control of a continuous mining machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiffbauer, W.H.

1993-12-31

This report details a microcomputer-based control and monitoring network that was developed in-house by the U.S. Bureau of Mines and installed on a continuous mining machine. The network consists of microcomputers that are connected together via a single twisted-pair cable. Each microcomputer was developed to provide a particular function in the control process. Machine-mounted microcomputers, in conjunction with the appropriate sensors, provide closed-loop control of the machine, navigation, and environmental monitoring. Off-the-machine microcomputers provide remote control of the machine, sensor status, and a connection to the network so that external computers can access network data and control the continuous miningmore » machine. Because of the network`s generic structure, it can be installed on most mining machines.« less

Validation of Optical Coherence Tomography against Micro-computed Tomography for Evaluation of Remaining Coronal Dentin Thickness.

PubMed

Majkut, Patrycja; Sadr, Alireza; Shimada, Yasushi; Sumi, Yasunori; Tagami, Junji

2015-08-01

Optical coherence tomography (OCT) is a noninvasive modality to obtain in-depth images of biological structures. A dental OCT system has become available for chairside application. This in vitro study hypothesized that swept-source OCT can be used to measure the remaining dentin thickness (RDT) at the roof of the dental pulp chamber during excavation of deep caries. Human molar teeth with deep occlusal caries were investigated. After obtaining 2-dimensional and 3-dimensional OCT scans using a swept-source OCT system at a 1330-nm center wavelength, RDT was evaluated by image analysis software. Microfocus x-ray computed tomographic (micro-CT) images were obtained from the same cross sections to confirm OCT findings. The smallest RDT values at the visible pulp horn were measured on OCT and micro-CT imaging and compared using the Pearson correlation. Pulpal horns and pulp chamber roof observation under OCT and micro-CT imaging resulted in comparable images that allowed the measurement of coronal dentin thickness. RDT measured by OCT showed optical values range between 140 and 2300 μm, which corresponded to the range of 92-1524 μm on micro-CT imaging. A strong correlation was found between the 2 techniques (r = 0.96, P < .001). Further analysis indicated linear regression with a slope of 1.54 and no intercept, closely matching the bulk refractive index of dentin. OCT enables visualization of anatomic structures during deep caries excavation. Exposure of the vital dental pulp because of the removal of very thin remaining coronal dentin can be avoided with this novel noninvasive technique. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Automated Power Systems Management (APSM)

NASA Technical Reports Server (NTRS)

Bridgeforth, A. O.

1981-01-01

A breadboard power system incorporating autonomous functions of monitoring, fault detection and recovery, command and control was developed, tested and evaluated to demonstrate technology feasibility. Autonomous functions including switching of redundant power processing elements, individual load fault removal, and battery charge/discharge control were implemented by means of a distributed microcomputer system within the power subsystem. Three local microcomputers provide the monitoring, control and command function interfaces between the central power subsystem microcomputer and the power sources, power processing and power distribution elements. The central microcomputer is the interface between the local microcomputers and the spacecraft central computer or ground test equipment.

The Feasibility of Implementing Multicommand Software Functions on a Microcomputer Network.

DTIC Science & Technology

1979-10-01

studies 20 ABSTRACT fConllnuo on revete &Ide it necessary and Identify by block number) ’This report presents the results of a study of design...considerations for hybrid monitor systems for distributed microcomputer networks. The objective of the study was to determine the feasibility of such monitor...Management Informa- tion and Computer Sciences. The study was one task on a project bentitled "The Feasibility of Implementing Multicommand Software

Personal Computers.

ERIC Educational Resources Information Center

Toong, Hoo-min D.; Gupta, Amar

1982-01-01

Describes the hardware, software, applications, and current proliferation of personal computers (microcomputers). Includes discussions of microprocessors, memory, output (including printers), application programs, the microcomputer industry, and major microcomputer manufacturers (Apple, Radio Shack, Commodore, and IBM). (JN)

Picking through Microcomputer Books.

ERIC Educational Resources Information Center

Lu, Cary

1984-01-01

Indicating that most microcomputer books aren't worth reading, offers several rules of thumb for selecting a microcomputer guide. Also provides a list of 13 noteworthy books, providing title, source, and current cost. (JN)

Microcomputers in Education: Uses for the '80s. Proceedings of the Annual Microcomputer Conference (2nd, Tempe, Arizona, January 15-16, 1982). Publication No. 3.

ERIC Educational Resources Information Center

Watson, Nancy Ralph, Ed.

The 30 conference papers in this collection are presented in 6 categories. Five overviews discuss innovative uses of computers in education (Dorothy K. Deringer); microcomputers in instructional research (Alan M. Lesgold); microcomputers in the schools (Mitchell Batoff, Gary G. Bitter); and the courseware crisis (Barbara R. Sadowski). Research and…

Periodontal regeneration with stem cells-seeded collagen-hydroxyapatite scaffold.

PubMed

Liu, Zeping; Yin, Xing; Ye, Qingsong; He, Wulin; Ge, Mengke; Zhou, Xiaofu; Hu, Jing; Zou, Shujuan

2016-07-01

Re-establishing compromised periodontium to its original structure, properties and function is demanding, but also challenging, for successful orthodontic treatment. In this study, the periodontal regeneration capability of collagen-hydroxyapatite scaffolds, seeded with bone marrow stem cells, was investigated in a canine labial alveolar bone defect model. Bone marrow stem cells were isolated, expanded and characterized. Porous collagen-hydroxyapatite scaffold and cross-linked collagen-hydroxyapatite scaffold were prepared. Attachment, migration, proliferation and morphology of bone marrow stem cells, co-cultured with porous collagen-hydroxyapatite or cross-linked collagen-hydroxyapatite, were evaluated in vitro. The periodontal regeneration capability of collagen-hydroxyapatite scaffold with or without bone marrow stem cells was tested in six beagle dogs, with each dog carrying one sham-operated site as healthy control, and three labial alveolar bone defects untreated to allow natural healing, treated with bone marrow stem cells - collagen-hydroxyapatite scaffold implant or collagen-hydroxyapatite scaffold implant, respectively. Animals were euthanized at 3 and 6 months (3 animals per group) after implantation and the resected maxillary and mandibular segments were examined using micro-computed tomography scan, H&E staining, Masson's staining and histometric evaluation. Bone marrow stem cells were successfully isolated and demonstrated self-renewal and multi-potency in vitro. The porous collagen-hydroxyapatite and cross-linked collagen-hydroxyapatite had average pore sizes of 415 ± 20 µm and 203 ± 18 µm and porosity of 69 ± 0.5% and 50 ± 0.2%, respectively. The attachment, proliferation and migration of bone marrow stem cells were satisfactory on both porous collagen-hydroxyapatite and cross-linked collagen-hydroxyapatite scaffolds. Implantation of bone marrow stem cells - collagen-hydroxyapatite or collagen-hydroxyapatite scaffold in beagle dogs with experimental periodontal defects resulted in significantly enhanced periodontal regeneration characterized by formation of new bone, periodontal ligament and cementum, compared with the untreated defects, as evidenced by histological and micro-computed tomography examinations. The prepared collagen-hydroxyapatite scaffolds possess favorable bio-compatibility. The bone marrow stem cells - collagen-hydroxyapatite and collagen-hydroxyapatite scaffold - induced periodontal regeneration, with no aberrant events complicating the regenerative process. Further research is necessary to improve the bone marrow stem cells behavior in collagen-hydroxyapatite scaffolds after implantation. © The Author(s) 2016.

Expansion of the Multi-Link Frontier™ Coronary Bifurcation Stent: Micro-Computed Tomographic Assessment in Human Autopsy and Porcine Heart Samples

PubMed Central

Kralev, Stefan; Haag, Benjamin; Spannenberger, Jens; Lang, Siegfried; Brockmann, Marc A.; Bartling, Soenke; Marx, Alexander; Haase, Karl-Konstantin; Borggrefe, Martin; Süselbeck, Tim

2011-01-01

Background Treatment of coronary bifurcation lesions remains challenging, beyond the introduction of drug eluting stents. Dedicated stent systems are available to improve the technical approach to the treatment of these lesions. However dedicated stent systems have so far not reduced the incidence of stent restenosis. The aim of this study was to assess the expansion of the Multi-Link (ML) Frontier™ stent in human and porcine coronary arteries to provide the cardiologist with useful in-vitro information for stent implantation and selection. Methodology/Principal Findings Nine ML Frontier™ stents were implanted in seven human autopsy heart samples with known coronary artery disease and five ML Frontier™ stents were implanted in five porcine hearts. Proximal, distal and side branch diameters (PD, DD, SBD, respectively), corresponding opening areas (PA, DA, SBA) and the mean stent length (L) were assessed by micro-computed tomography (micro-CT). PD and PA were significantly smaller in human autopsy heart samples than in porcine heart samples (3.54±0.47 mm vs. 4.04±0.22 mm, p = 0.048; 10.00±2.42 mm2 vs. 12.84±1.38 mm2, p = 0.034, respectively) and than those given by the manufacturer (3.54±0.47 mm vs. 4.03 mm, p = 0.014). L was smaller in human autopsy heart samples than in porcine heart samples, although data did not reach significance (16.66±1.30 mm vs. 17.30±0.51 mm, p = 0.32), and significantly smaller than that given by the manufacturer (16.66±1.30 mm vs. 18 mm, p = 0.015). Conclusions/Significance Micro-CT is a feasible tool for exact surveying of dedicated stent systems and could make a contribution to the development of these devices. The proximal diameter and proximal area of the stent system were considerably smaller in human autopsy heart samples than in porcine heart samples and than those given by the manufacturer. Special consideration should be given to the stent deployment procedure (and to the follow-up) of dedicated stent systems, considering final intravascular ultrasound or optical coherence tomography to visualize (and if necessary optimize) stent expansion. PMID:21814552

Rescuing Perishable Neuroanatomical Information from a Threatened Biodiversity Hotspot: Remote Field Methods for Brain Tissue Preservation Validated by Cytoarchitectonic Analysis, Immunohistochemistry, and X-Ray Microcomputed Tomography.

PubMed

Hughes, Daniel F; Walker, Ellen M; Gignac, Paul M; Martinez, Anais; Negishi, Kenichiro; Lieb, Carl S; Greenbaum, Eli; Khan, Arshad M

2016-01-01

Biodiversity hotspots, which harbor more endemic species than elsewhere on Earth, are increasingly threatened. There is a need to accelerate collection efforts in these regions before threatened or endangered species become extinct. The diverse geographical, ecological, genetic, morphological, and behavioral data generated from the on-site collection of an individual specimen are useful for many scientific purposes. However, traditional methods for specimen preparation in the field do not permit researchers to retrieve neuroanatomical data, disregarding potentially useful data for increasing our understanding of brain diversity. These data have helped clarify brain evolution, deciphered relationships between structure and function, and revealed constraints and selective pressures that provide context about the evolution of complex behavior. Here, we report our field-testing of two commonly used laboratory-based techniques for brain preservation while on a collecting expedition in the Congo Basin and Albertine Rift, two poorly known regions associated with the Eastern Afromontane biodiversity hotspot. First, we found that transcardial perfusion fixation and long-term brain storage, conducted in remote field conditions with no access to cold storage laboratory equipment, had no observable impact on cytoarchitectural features of lizard brain tissue when compared to lizard brain tissue processed under laboratory conditions. Second, field-perfused brain tissue subjected to prolonged post-fixation remained readily compatible with subsequent immunohistochemical detection of neural antigens, with immunostaining that was comparable to that of laboratory-perfused brain tissue. Third, immersion-fixation of lizard brains, prepared under identical environmental conditions, was readily compatible with subsequent iodine-enhanced X-ray microcomputed tomography, which facilitated the non-destructive imaging of the intact brain within its skull. In summary, we have validated multiple approaches to preserving intact lizard brains in remote field conditions with limited access to supplies and a high degree of environmental exposure. This protocol should serve as a malleable framework for researchers attempting to rescue perishable and irreplaceable morphological and molecular data from regions of disappearing biodiversity. Our approach can be harnessed to extend the numbers of species being actively studied by the neuroscience community, by reducing some of the difficulty associated with acquiring brains of animal species that are not readily available in captivity.

Rescuing Perishable Neuroanatomical Information from a Threatened Biodiversity Hotspot: Remote Field Methods for Brain Tissue Preservation Validated by Cytoarchitectonic Analysis, Immunohistochemistry, and X-Ray Microcomputed Tomography

PubMed Central

Hughes, Daniel F.; Walker, Ellen M.; Gignac, Paul M.; Martinez, Anais; Negishi, Kenichiro; Lieb, Carl S.; Greenbaum, Eli

2016-01-01

Biodiversity hotspots, which harbor more endemic species than elsewhere on Earth, are increasingly threatened. There is a need to accelerate collection efforts in these regions before threatened or endangered species become extinct. The diverse geographical, ecological, genetic, morphological, and behavioral data generated from the on-site collection of an individual specimen are useful for many scientific purposes. However, traditional methods for specimen preparation in the field do not permit researchers to retrieve neuroanatomical data, disregarding potentially useful data for increasing our understanding of brain diversity. These data have helped clarify brain evolution, deciphered relationships between structure and function, and revealed constraints and selective pressures that provide context about the evolution of complex behavior. Here, we report our field-testing of two commonly used laboratory-based techniques for brain preservation while on a collecting expedition in the Congo Basin and Albertine Rift, two poorly known regions associated with the Eastern Afromontane biodiversity hotspot. First, we found that transcardial perfusion fixation and long-term brain storage, conducted in remote field conditions with no access to cold storage laboratory equipment, had no observable impact on cytoarchitectural features of lizard brain tissue when compared to lizard brain tissue processed under laboratory conditions. Second, field-perfused brain tissue subjected to prolonged post-fixation remained readily compatible with subsequent immunohistochemical detection of neural antigens, with immunostaining that was comparable to that of laboratory-perfused brain tissue. Third, immersion-fixation of lizard brains, prepared under identical environmental conditions, was readily compatible with subsequent iodine-enhanced X-ray microcomputed tomography, which facilitated the non-destructive imaging of the intact brain within its skull. In summary, we have validated multiple approaches to preserving intact lizard brains in remote field conditions with limited access to supplies and a high degree of environmental exposure. This protocol should serve as a malleable framework for researchers attempting to rescue perishable and irreplaceable morphological and molecular data from regions of disappearing biodiversity. Our approach can be harnessed to extend the numbers of species being actively studied by the neuroscience community, by reducing some of the difficulty associated with acquiring brains of animal species that are not readily available in captivity. PMID:27196138

Choosing a Microcomputer: A Success Story.

ERIC Educational Resources Information Center

Mason, Robert M.

1983-01-01

Documentation of author's personal experience in the purchasing of a microcomputer discusses background learning, the purchase decision, needs assessment, computer literacy, general information on microcomputers, the situation assessment, and the final check. (EJS)

Introduction to Computers & Introduction to Word Processing: Integrating Content Area Coursework into College Reading/Study Skills Curricula Using Microcomputers.

ERIC Educational Resources Information Center

Balajthy, Ernest; And Others

A study examined the planning, implementation, and evaluation of a curriculum designed to teach 60 college level developmental reading students to use microcomputers (Apple) as learning tools and to improve their content area reading ability. The textbook from a biology course in which all but three of the subjects were enrolled was the source for…

Integrating Physics and Math through Microcomputer-Based Laboratories (MBL): Effects on Discourse Type, Quality, and Mathematization

ERIC Educational Resources Information Center

BouJaoude, Saouma B.; Jurdak, Murad E.

2010-01-01

The purposes of this study were to understand the nature of discourse in terms of knowledge types and cognitive process, source of utterances (student or teacher), and time use in microcomputer-based labs (MBL) and verification type labs (VTL) and to gain an understanding of the role of MBL in promoting mathematization. The study was conducted in…

Integrating Computers into the Accounting Curriculum Using an IBM PC Network. Final Report.

ERIC Educational Resources Information Center

Shaoul, Jean

Noting the increased use of microcomputers in commerce and the accounting profession, the Department of Accounting and Finance at the University of Manchester recognized the importance of integrating microcomputers into the accounting curriculum and requested and received a grant to develop an integrated study environment in which students would…

Prospects and Challenges for Using Microcomputers in School. Technical Report No. 7.

ERIC Educational Resources Information Center

Pea, Roy D.

Prepared as an address for educator groups, this paper provides a theoretical perspective for thinking about problems and prospects for integrating microcomputer uses in school activities. Six major aspects of the perspective are defined: (1) the computer as general-purpose symbolic device; (2) the importance of developmental studies of children's…

Microcomputer Database Management Systems that Interface with Online Public Access Catalogs.

ERIC Educational Resources Information Center

Rice, James

1988-01-01

Describes a study that assessed the availability and use of microcomputer database management interfaces to online public access catalogs. The software capabilities needed to effect such an interface are identified, and available software packages are evaluated by these criteria. A directory of software vendors is provided. (4 notes with…

ASCAL: A Microcomputer Program for Estimating Logistic IRT Item Parameters.

ERIC Educational Resources Information Center

Vale, C. David; Gialluca, Kathleen A.

ASCAL is a microcomputer-based program for calibrating items according to the three-parameter logistic model of item response theory. It uses a modified multivariate Newton-Raphson procedure for estimating item parameters. This study evaluated this procedure using Monte Carlo Simulation Techniques. The current version of ASCAL was then compared to…

Microcomputers in the Classroom: Trojan Horse or Teacher's Pet?

ERIC Educational Resources Information Center

Olson, John K.

Arguing that curriculum developers need to seek a better understanding of existing classroom orders before advising reform through new technology, this paper presents a review of research on the effects of microcomputers on the stabilities of classroom practice and describes a pilot study currently underway at Queens University in Ontario to…

Microcomputer Based Computer-Assisted Learning System: CASTLE.

ERIC Educational Resources Information Center

Garraway, R. W. T.

The purpose of this study was to investigate the extent to which a sophisticated computer assisted instruction (CAI) system could be implemented on the type of microcomputer system currently found in the schools. A method was devised for comparing CAI languages and was used to rank five common CAI languages. The highest ranked language, NATAL,…

Effect of Korean Red Ginseng on radiation-induced bone loss in C3H/HeN mice

PubMed Central

Lee, Jin-Hee; Lee, Hae-June; Yang, Miyoung; Moon, Changjong; Kim, Jong-Choon; Bae, Chun-Sik; Jo, Sung-Kee; Jang, Jong-Sik; Kim, Sung-Ho

2013-01-01

This study investigated the effects of Korean Red Ginseng (KRG) on radiation-induced bone loss in C3H/HeN mice. C3H/HeN mice were divided into sham and irradiation (3 Gy, gamma-ray) groups. The irradiated mice were treated for 12 wk with vehicle, KRG (per os, p.o.) or KRG (intraperitoneal). Serum alkaline phosphatase (ALP), tartrate-resistant acid phosphatase, estradiol level, and biomechanical properties were measured. Tibiae were analyzed using micro-computed tomography. Treatment of KRG (p.o., 250 mg/kg of body weight/d) significantly preserved trabecular bone volume, trabecular number, structure model index, and bone mineral density of proximal tibia metaphysic, but did not alter the uterus weight of the mice. Serum ALP level was slightly reduced by KRG treatment. However, grip strength, mechanical property, and cortical bone architecture did not differ among the experimental groups. The results indicate that KRG can prevent radiation-induced bone loss in mice. PMID:24233384

Fetal Cardiac Impairment in Nitrofen-Induced Congenital Diaphragmatic Hernia: Postmortem Microcomputed Tomography Imaging Study.

PubMed

Pelizzo, Gloria; Calcaterra, Valeria; Lombardi, Claudio; Bussani, Rossana; Zambelli, Vanessa; De Silvestri, Annalisa; Custrin, Ana; Belgrano, Manuel; Zennaro, Floriana

2017-08-01

We assessed the post-mortem micro-CT utility to evaluate fetal cardiac impairment in nitrofen-induced congenital diaphragmatic hernia (CDH). At 9.5d postconception (dpc), pregnant rats were exposed to nitrofen. At +18 and +21dpc, fetuses were harvested by cesarean section. Postmortem micro-CT and autopsy were performed. Fetuses were assigned to three experimental groups: Control group (C), Nitrofen group (N, exposition to nitrofen without CDH), CDH group. Cardio-pulmonary indices were evaluated. An accurate morphological evaluation of the lung and heart was obtained. Early cardiac impairment was present in the N and CDH groups. At term pregnancy, an increased maximum diameter and decreased minimum diameter of the ventricles and increased interventricular septal thickness were noted in CDH. Histology showed a myocardial "disarray" and an high density of mitotic myocytes in CDH at midgestation. The potential utility of post-mortem fetal micro-CT examination in CDH was introduced. The results highlighted the presence of cardiac adaptation in affected fetuses.

A secreted bacterial protease tailors the Staphylococcus aureus virulence repertoire to modulate bone remodeling during osteomyelitis

PubMed Central

Cassat, James E.; Hammer, Neal D.; Campbell, J. Preston; Benson, Meredith A.; Perrien, Daniel S.; Mrak, Lara N.; Smeltzer, Mark S.; Torres, Victor J.; Skaar, Eric P.

2013-01-01

Summary Osteomyelitis is a common manifestation of invasive Staphylococcus aureus infection. Pathogen-induced bone destruction limits antimicrobial penetration to the infectious focus and compromises treatment of osteomyelitis. To investigate mechanisms of S. aureus-induced bone destruction, we developed a murine model of osteomyelitis. Micro-computed tomography of infected femurs revealed that S. aureus triggers profound alterations in bone turnover. The bacterial regulatory locus sae was found to be critical for osteomyelitis pathogenesis, as Sae-regulated factors promote pathologic bone remodeling and intraosseous bacterial survival. Exoproteome analyses revealed the Sae-regulated protease aureolysin as a major determinant of the S. aureus secretome and identified the phenol soluble modulins as aureolysin-degraded, osteolytic peptides that trigger osteoblast cell death and bone destruction. These studies establish a murine model for pathogen-induced bone remodeling, define Sae as critical for osteomyelitis pathogenesis, and identify protease-dependent exoproteome remodeling as a major determinant of the staphylococcal virulence repertoire. PMID:23768499

Micro-CT evaluation of apical delta morphologies in human teeth.

PubMed

Gao, Xianhua; Tay, Franklin R; Gutmann, James L; Fan, Wei; Xu, Ting; Fan, Bing

2016-11-07

The apical delta is an intricate system within the root canal and incompletely debridement may affect the long-term prognosis of root canal therapy. The aim of the present study is to investigate the morphologic features of apical deltas in human teeth with micro-computed tomography (micro-CT) using a centreline-fitting algorithm. One hundred and thirty-six apical deltas were detected in 1400 teeth. Molars had more apical deltas (15.8%) than anterior teeth (6.3%). In maxillary molars, the mesiobuccal root had a significantly higher prevalence of apical delta than the palatal root or the distobuccal root. The median vertical distance of the apical delta was 1.87 mm with 13% more than 3 mm. The median diameter and length of the apical delta branches were 132.3 and 934.5 μm. Apical delta branches were not straight with cross-sectional shapes being non-circular. These morphological features of apical delta may complicate debridement of the infected root canal system.

Onset of molar incisor hypomineralization (MIH).

PubMed

Fagrell, Tobias G; Salmon, Phil; Melin, Lisa; Norén, Jörgen G

2013-01-01

The etiological factors and timing of the onset of molar incisor hypomineralization (MIH) are still not clear. The aim of this study was to examine ground radial and sagittal sections from teeth diagnosed with MIH using light microscopy, polarized light microscopy and X-ray micro-computed tomography (XMCT) and to estimate the onset and timing of the MIH and to relate the hypomineralized enamel to the incremental lines. Thirteen extracted permanent first molars diagnosed MIH, were analyzed with light microscopy and XMCT. The hypomineralized areas were mainly located in the mesio-buccal cusps, starting at the enamel-dentin-junction and continuing towards the enamel surface. In a relative gray scale analysis the values decreased from the EDJ towards the enamel surface. The findings indicate that the ameloblasts in the hypomineralized enamel are capable of forming an enamel of normal thickness, but with a substantial reduction of their capacity for maturation of enamel. Chronologically, it is estimated that the timing of the disturbance is at a period during the first 6-7 months of age.

Changed morphology and mechanical properties of cancellous bone in the mandibular condyles of edentate people.

PubMed

Giesen, E B W; Ding, M; Dalstra, M; van Eijden, T M G J

2004-03-01

Since edentate subjects have a reduced masticatory function, it can be expected that the morphology of the cancellous bone of their mandibular condyles has changed according to the altered mechanical environment. In the present study, the morphology of cylindrical cancellous bone specimens of the mandibular condyles of edentate subjects (n = 25) was compared with that of dentate subjects (n = 24) by means of micro-computed tomography and by the application of Archimedes' principle. Stiffness and strength were determined by destructive mechanical testing. Compared with dentate subjects, it appeared that, in edentate subjects, the bone was less dense and the trabecular structure was less plate-like. The regression models of stiffness and strength built from bone volume fraction and the trabecular orientation relative to the axis of the specimen were similar for both dentate and edentate subjects. This indicates that, under reduced mechanical load, the fundamental relationship between bone morphology and mechanical properties does not change.

Spontaneous emergence of overgrown molar teeth in a colony of Prairie voles (Microtus ochrogaster)

PubMed Central

Jheon, Andrew H; Prochazkova, Michaela; Sherman, Michael; Manoli, Devanand S; Shah, Nirao M; Carbone, Lawrence; Klein, Ophir

2015-01-01

Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defects in a population of Prairie voles (Microtus ochrogaster). We identified bilateral protuberances on the ventral surface of the mandible in several voles in our colony. In some cases, the protuberances broke through the cortical bone. The mandibular molars became exposed and infected, and the maxillary molars entered the cranial vault. Visualisation upon soft tissue removal and microcomputed tomography (microCT) analyses confirmed that the protuberances were caused by the overgrowth of the apical ends of the molar teeth. We speculate that the unrestricted growth of the molars was due to the misregulation of the molar dental stem cell niche. Further study of this molar phenotype may yield additional insight into stem cell regulation and the evolution and development of continuously growing teeth. PMID:25634121

Effect of Low-Intensity Pulsed Ultrasound after Mesenchymal Stromal Cell Injection to Treat Osteochondral Defects: An In Vivo Study.

PubMed

Yamaguchi, Shoki; Aoyama, Tomoki; Ito, Akira; Nagai, Momoko; Iijima, Hirotaka; Tajino, Junichi; Zhang, Xiangkai; Wataru, Kiyan; Kuroki, Hiroshi

2016-12-01

We investigated the effect of low-intensity pulsed ultrasound (LIPUS) treatment combined with mesenchymal stromal cell (MSC) injection for cartilage repair and subchondral bone reconstitution for treatment of osteochondral defects. An osteochondral defect was created on both femur grooves of Wistar rats. Four weeks later, bone marrow MSCs were injected into the right knee joint. The rats were divided into two intervention groups: without or with LIPUS irradiation. Cartilage repair was evaluated histologically based on the Wakitani cartilage repair score. Subchondral bone reconstitution was evaluated as bone volume (BV)/tissue volume (TV) by micro-computed tomography analysis. MSC injection improved the cartilage repair score, and LIPUS irradiation improved BV/TV. Combination treatment promoted both cartilage repair and BV/TV improvement. Thus, MSC injection combined with LIPUS irradiation is more effective than either treatment alone in promoting concurrent cartilage repair and subchondral reconstitution. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Anti-osteopontin monoclonal antibody prevents ovariectomy-induced osteoporosis in mice by promotion of osteoclast apoptosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Bo; PLA General Hospital Cancer Center and PLA Cancer Research Institute, PLA Postgraduate School of Medicine, 28 Fuxing Road, Beijing; Dai, Jianxin

Highlight: • We first report that anti-osteopontin mAb could protect osteoporosis in mice. • Anti-osteopontin mAb could promote the osteoclast apoptosis. • Targeting osteopontin might have therapeutic potentials for osteoporosis. - Abstract: Osteopontin (OPN) is abundant in mineralized tissues and has long been implicated in bone remodeling. However, the therapeutic effect of targeting OPN in bone loss diseases and the underlying molecular mechanism remain largely unknown. Here, we reported that anti-OPN mAb (23C3) could protect against ovariectomy-induced osteoporosis in mice, demonstrated by microcomputed tomography analysis and histopathology evaluation. In vitro assay showed that 23C3 mAb reduced osteoclasts (OCs)-mediated bone resorptionmore » through promotion of mature OC apoptosis. Thus, the study has important implications for understanding the role of OPN in OC bone resorption and survival, and OPN antagonists may have therapeutic potential for osteoporosis and other osteopenic diseases.« less

Eco-evo-devo in the Study of Adaptive Divergence: Examples from Threespine Stickleback (Gasterosteus aculeatus).

PubMed

Jamniczky, Heather A; Barry, Tegan N; Rogers, Sean M

2015-07-01

The tight fit between form and function in organisms suggests the influence of adaptive evolution in biomechanics; however, the prevalence of adaptive traits, the mechanisms by which they arise and the corresponding responses to selection are subjects of extensive debate. We used three-dimensional microcomputed tomography and geometric morphometrics to characterize the structure of phenotypic covariance within the G. aculeatus trophic apparatus and its supporting structures in wild and controlled crosses of fish from two different localities. Our results reveal that while the structure of phenotypic covariance is conserved in marine and freshwater forms, it may be disrupted in the progeny of artificial crosses or during rapid adaptive divergence events. We discuss these results within the context of integrating covariance structure with quantitative genetics, toward establishing predictive links between genes, development, biomechanics, and the environment. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Microcomputer Software Development: New Strategies for a New Technology.

ERIC Educational Resources Information Center

Kehrberg, Kent T.

1979-01-01

Provides a guide for the development of educational computer programs for use on microcomputers. Making use of the features of microcomputers, including visual, audio, and tactile techniques, is encouraged. (Author/IRT)

Applications of microcomputers in bridge design.

DOT National Transportation Integrated Search

1986-01-01

The utilization of microcomputers in bridge design activities in state transportation departments was evaluated through contacts with 32 state agencies. While the present utilization of microcomputers was found to be limited, subsequent research show...

Implementation and use of a microcomputer-based management information system to monitor dairy herd performance

PubMed Central

Lissemore, Kerry D.; Leslie, Ken E.; Menzies, Paula I.; Martin, S. Wayne; Meek, Alan H.; Etherington, Wayne G.

1992-01-01

A microcomputer-based herd management information system was implemented as part of the herd health program provided to 13 dairy clients by the Ontario Veterinary College, University of Guelph. The study was conducted over a two year period. Data were collected from on-farm event diaries, veterinary visit reports, and production testing information. Selected indices of reproduction, udder health, production, and heifer performance were reported. It was concluded that the implementation of a microcomputer-based information management system, operated as a bureau service, was feasible. However, limitations to the implementation in veterinary practice were identified. PMID:17423945

Evaluation of a polyetheretherketone (PEEK) titanium composite interbody spacer in an ovine lumbar interbody fusion model: biomechanical, microcomputed tomographic, and histologic analyses.

PubMed

McGilvray, Kirk C; Waldorff, Erik I; Easley, Jeremiah; Seim, Howard B; Zhang, Nianli; Linovitz, Raymond J; Ryaby, James T; Puttlitz, Christian M

2017-12-01

The most commonly used materials used for interbody cages are titanium metal and polymer polyetheretherketone (PEEK). Both of these materials have demonstrated good biocompatibility. A major disadvantage associated with solid titanium cages is their radiopacity, limiting the postoperative monitoring of spinal fusion via standard imaging modalities. However, PEEK is radiolucent, allowing for a temporal assessment of the fusion mass by clinicians. On the other hand, PEEK is hydrophobic, which can limit bony ingrowth. Although both PEEK and titanium have demonstrated clinical success in obtaining a solid spinal fusion, innovations are being developed to improve fusion rates and to create stronger constructs using hybrid additive manufacturing approaches by incorporating both materials into a single interbody device. The purpose of this study was to examine the interbody fusion characteristic of a PEEK Titanium Composite (PTC) cage for use in lumbar fusion. Thirty-four mature female sheep underwent two-level (L 2 -L 3 and L 4 -L 5 ) interbody fusion using either a PEEK or a PTC cage (one of each per animal). Animals were sacrificed at 0, 8, 12, and 18 weeks post surgery. Post sacrifice, each surgically treated functional spinal unit underwent non-destructive kinematic testing, microcomputed tomography scanning, and histomorphometric analyses. Relative to the standard PEEK cages, the PTC constructs demonstrated significant reductions in ranges of motion and a significant increase in stiffness. These biomechanical findings were reinforced by the presence of significantly more bone at the fusion site as well as ingrowth into the porous end plates. Overall, the results indicate that PTC interbody devices could potentially lead to a more robust intervertebral fusion relative to a standard PEEK device in a clinical setting. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Library Computing

ERIC Educational Resources Information Center

Library Computing, 1985

1985-01-01

Special supplement to "Library Journal" and "School Library Journal" covers topics of interest to school, public, academic, and special libraries planning for automation: microcomputer use, readings in automation, online searching, databases of microcomputer software, public access to microcomputers, circulation, creating a…

Why Micros?

ERIC Educational Resources Information Center

Myers, Darlene

1983-01-01

Discusses development of the first computers; identifies five generations of computers; reviews projections for sales and proliferation of microcomputers into the marketplace; outlines procedures for selecting microcomputers and evaluating software; and reviews several articles on microcomputers centering on user requirements. (MBR)

Micro-structural integrity of dental enamel subjected to two tooth whitening regimes.

PubMed

Tanaka, Reina; Shibata, Yo; Manabe, Atsufumi; Miyazaki, Takashi

2010-04-01

Colour modification of tooth enamel has proven successful, but it is unclear how various bleaching applications affect micro-structural integrity of the whitened enamel. To investigate the internal structural integrity of human intact tooth enamel with the application of two commonly used whitening regimes (in-office power bleaching with 35% hydrogen peroxide and home bleaching with 10% carbamide peroxide), evaluations were performed on teeth of identical colour classification. After the bleaching applications, the enamel mineral density was quantified and visualised with micro-computed tomography. The micro-structural differences between the whitened tooth enamel samples were distinctive, though the colour parameter changes within the samples were equivalent. Home bleaching achieved colour modification by demineralisation, whereas in-office bleaching depended on redistribution of the minerals after treatment and subsequent enhanced mineralisation.

A feast of visualization

NASA Astrophysics Data System (ADS)

2008-12-01

Strength through structure The visualization and assessment of inner human bone structures can provide better predictions of fracture risk due to osteoporosis. Using micro-computed tomography (µCT), Christoph Räth from the Max Planck Institute for Extraterrestrial Physics and colleagues based in Munich, Vienna and Salzburg have shown how complex lattice-shaped bone structures can be visualized. The structures were quantified by calculating certain "texture measures" that yield new information about the stability of the bone. A 3D visualization showing the variation with orientation of one of the texture measures for four different bone specimens (from left to right) is shown above. Such analyses may help us to improve our understanding of disease and drug-induced changes in bone structure (C Räth et al. 2008 New J. Phys. 10 125010).

Microcomputers and Literacy.

ERIC Educational Resources Information Center

Grice, R. D.

1986-01-01

The nature of literacy associated with the widely used new medium of microcomputers has not been fully exploited by schools to foster development of literacy programs. Microcomputer applications need integration with classroom activities where students construct language meaning. (19 references) (CJH)

Impact of Personal Computing on Education.

ERIC Educational Resources Information Center

McIsaac, Donald N.

1979-01-01

Describes microcomputers, outlines lessons learned from the evolution of other technologies as they apply to the development of the microcomputer, discusses computer literacy as a problem-solving tool, and speculates about microcomputer use in instruction and administration. (IRT)

[General-purpose microcomputer for medical laboratory instruments].

PubMed

Vil'ner, G A; Dudareva, I E; Kurochkin, V E; Opalev, A A; Polek, A M

1984-01-01

Presented in the paper is the microcomputer based on the KP580 microprocessor set. Debugging of the hardware and the software by using the unique debugging stand developed on the basis of microcomputer "Electronica-60" is discussed.

Circulation Systems on Microcomputers.

ERIC Educational Resources Information Center

Carlson, Gary

1984-01-01

Reports on the use of microcomputers in comprehensive library circulation systems. Topics covered include system requirements (reliability, completeness); determining circulation system needs (saving money, improving service, modernization); limitations of microcomputers (capacity, kinds of data stored, number of stations or terminals); system…

Microcomputer network for control of a continuous mining machine. Information circular/1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiffbauer, W.H.

1993-01-01

The paper details a microcomputer-based control and monitoring network that was developed in-house by the U.S. Bureau of Mines, and installed on a Joy 14 continuous mining machine. The network consists of microcomputers that are connected together via a single twisted pair cable. Each microcomputer was developed to provide a particular function in the control process. Machine-mounted microcomputers in conjunction with the appropriate sensors provide closed-loop control of the machine, navigation, and environmental monitoring. Off-the-machine microcomputers provide remote control of the machine, sensor status, and a connection to the network so that external computers can access network data and controlmore » the continuous mining machine. Although the network was installed on a Joy 14 continuous mining machine, its use extends beyond it. Its generic structure lends itself to installation onto most mining machine types.« less

Techniques in helical scanning, dynamic imaging and image segmentation for improved quantitative analysis with X-ray micro-CT

NASA Astrophysics Data System (ADS)

Sheppard, Adrian; Latham, Shane; Middleton, Jill; Kingston, Andrew; Myers, Glenn; Varslot, Trond; Fogden, Andrew; Sawkins, Tim; Cruikshank, Ron; Saadatfar, Mohammad; Francois, Nicolas; Arns, Christoph; Senden, Tim

2014-04-01

This paper reports on recent advances at the micro-computed tomography facility at the Australian National University. Since 2000 this facility has been a significant centre for developments in imaging hardware and associated software for image reconstruction, image analysis and image-based modelling. In 2010 a new instrument was constructed that utilises theoretically-exact image reconstruction based on helical scanning trajectories, allowing higher cone angles and thus better utilisation of the available X-ray flux. We discuss the technical hurdles that needed to be overcome to allow imaging with cone angles in excess of 60°. We also present dynamic tomography algorithms that enable the changes between one moment and the next to be reconstructed from a sparse set of projections, allowing higher speed imaging of time-varying samples. Researchers at the facility have also created a sizeable distributed-memory image analysis toolkit with capabilities ranging from tomographic image reconstruction to 3D shape characterisation. We show results from image registration and present some of the new imaging and experimental techniques that it enables. Finally, we discuss the crucial question of image segmentation and evaluate some recently proposed techniques for automated segmentation.

MARS: a mouse atlas registration system based on a planar x-ray projector and an optical camera

NASA Astrophysics Data System (ADS)

Wang, Hongkai; Stout, David B.; Taschereau, Richard; Gu, Zheng; Vu, Nam T.; Prout, David L.; Chatziioannou, Arion F.

2012-10-01

This paper introduces a mouse atlas registration system (MARS), composed of a stationary top-view x-ray projector and a side-view optical camera, coupled to a mouse atlas registration algorithm. This system uses the x-ray and optical images to guide a fully automatic co-registration of a mouse atlas with each subject, in order to provide anatomical reference for small animal molecular imaging systems such as positron emission tomography (PET). To facilitate the registration, a statistical atlas that accounts for inter-subject anatomical variations was constructed based on 83 organ-labeled mouse micro-computed tomography (CT) images. The statistical shape model and conditional Gaussian model techniques were used to register the atlas with the x-ray image and optical photo. The accuracy of the atlas registration was evaluated by comparing the registered atlas with the organ-labeled micro-CT images of the test subjects. The results showed excellent registration accuracy of the whole-body region, and good accuracy for the brain, liver, heart, lungs and kidneys. In its implementation, the MARS was integrated with a preclinical PET scanner to deliver combined PET/MARS imaging, and to facilitate atlas-assisted analysis of the preclinical PET images.

MARS: a mouse atlas registration system based on a planar x-ray projector and an optical camera.

PubMed

Wang, Hongkai; Stout, David B; Taschereau, Richard; Gu, Zheng; Vu, Nam T; Prout, David L; Chatziioannou, Arion F

2012-10-07

This paper introduces a mouse atlas registration system (MARS), composed of a stationary top-view x-ray projector and a side-view optical camera, coupled to a mouse atlas registration algorithm. This system uses the x-ray and optical images to guide a fully automatic co-registration of a mouse atlas with each subject, in order to provide anatomical reference for small animal molecular imaging systems such as positron emission tomography (PET). To facilitate the registration, a statistical atlas that accounts for inter-subject anatomical variations was constructed based on 83 organ-labeled mouse micro-computed tomography (CT) images. The statistical shape model and conditional Gaussian model techniques were used to register the atlas with the x-ray image and optical photo. The accuracy of the atlas registration was evaluated by comparing the registered atlas with the organ-labeled micro-CT images of the test subjects. The results showed excellent registration accuracy of the whole-body region, and good accuracy for the brain, liver, heart, lungs and kidneys. In its implementation, the MARS was integrated with a preclinical PET scanner to deliver combined PET/MARS imaging, and to facilitate atlas-assisted analysis of the preclinical PET images.

Blood-pool contrast agent for pre-clinical computed tomography

NASA Astrophysics Data System (ADS)

Cruje, Charmainne; Tse, Justin J.; Holdsworth, David W.; Gillies, Elizabeth R.; Drangova, Maria

2017-03-01

Advances in nanotechnology have led to the development of blood-pool contrast agents for micro-computed tomography (micro-CT). Although long-circulating nanoparticle-based agents exist for micro-CT, they are predominantly based on iodine, which has a low atomic number. Micro-CT contrast increases when using elements with higher atomic numbers (i.e. lanthanides), particularly at higher energies. The purpose of our work was to develop and evaluate a lanthanide-based blood-pool contrast agent that is suitable for in vivo micro-CT. We synthesized a contrast agent in the form of polymer-encapsulated Gd nanoparticles and evaluated its stability in vitro. The synthesized nanoparticles were shown to have an average diameter of 127 +/- 6 nm, with good size dispersity. Particle size distribution - evaluated by dynamic light scattering over the period of two days - demonstrated no change in size of the contrast agent in water and saline. Additionally, our contrast agent was stable in a mouse serum mimic for up to 30 minutes. CT images of the synthesized contrast agent (containing 27 mg/mL of Gd) demonstrated an attenuation of over 1000 Hounsfield Units. This approach to synthesizing a Gd-based blood-pool contrast agent promises to enhance the capabilities of micro-CT imaging.

Networking the Home and University: How Families Can Be Integrated into Proximate/Distant Computer Systems.

ERIC Educational Resources Information Center

Watson, J. Allen; And Others

1989-01-01

Describes study that was conducted to determine the feasibility of networking home microcomputers with a university mainframe system in order to investigate a new family process research paradigm, as well as the design and function of the microcomputer/mainframe system. Test instrumentation is described and systems' reliability and validity are…

Vocational-Technical Microcomputer Applications in Michigan and Bordering States (Upper Midwest Region). A Status Report: Summer 1984.

ERIC Educational Resources Information Center

Harris, Richard; Obert, Deborah

In summer 1984, a study was conducted to assess the status of microcomputer applications in the public vocational-technical facilities of Michigan, Indiana, Minnesota, Illinois, Ohio, and Wisconsin. Mailing lists provided by the vocational education divisions of each state department of education were used to survey 705 individuals regarding…

A Comparison of the Effectiveness of Microcomputer and Workbook Instruction on Reading Comprehension Performance of High Incidence Handicapped Children.

ERIC Educational Resources Information Center

Harper, Janice A.; Ewing, Norma J.

1986-01-01

This study compared the effectiveness of microcomputer and workbook instruction on silent reading comprehension performance of mild mentally retarded and learning disabled 11- to 13-year-olds. Effectiveness was measured by percentage of correct responses to reading comprehension questions and by observing subjects' attention to task behavior. (MBR)

Automating Reference Desk Files with Microcomputers in a Public Library: An Exploration of Data Resources, Methods, and Software.

ERIC Educational Resources Information Center

Miley, David W.

Many reference librarians still rely on manual searches to access vertical files, ready reference files, and other information stored in card files, drawers, and notebooks scattered around the reference department. Automated access to these materials via microcomputers using database management software may speed up the process. This study focuses…

Proceedings of the Annual Penn State Microcomputer Information Exchange Conference (2nd, University Park, Pennsylvania, March 11-12, 1983).

ERIC Educational Resources Information Center

Streibel, Michael J., Comp.

This collection of 17 conference presentations includes (1) "Project LOGO: A Study in Cognitive Enhancement Using Microcomputers," Henry Dobson; (2) "Tender Loving Care for Your Terrific Little Computer (TLC for your TLC)," Carol Dwyer and Karl Kelly; (3) "Teaching Micro-Literacy to Kids," Robert Gillingham; (5)…

Cognitive Style Factors and Learning from Micro-Computer Based and Programmed Instructional Materials: A Preliminary Analysis.

ERIC Educational Resources Information Center

Canelos, James; And Others

This study examined the effects of two cognitive styles--field dependents-independents and reflectivity-impulsivity--on learning from microcomputer-based instruction. In the first of three experimental designs, a programmed instruction text on the human heart was used which contained both visual and verbal information in an instructional display,…

The Differentiation of Heat and Temperature: An Evaluation of the Effect of Microcomputer Models on Students' Misconceptions.

ERIC Educational Resources Information Center

Wiser, Marianne; Kipman, Daphna

This paper describes the characterization of a student's framework of heat and temperature, and the development of a microcomputer-based laboratories (MBL) intervention program for grade 9 and grade ll students. The report presents the results of classroom study, including interview questions and answers and pretest/posttest, from experimental and…

Utilization of a Microcomputer for the Study of an Iodine Oxidation and Equilibrium Reaction: A Physical Chemistry Experiment.

ERIC Educational Resources Information Center

Julien, L. M.

1984-01-01

Describes a physical chemistry experiment which incorporates the use of a microcomputer to enhance understanding of combined kinetic and equilibrium phenomena, to increase experimental capabilities when working with large numbers of students and limited equipment, and for the student to develop a better understanding of experimental design. (JN)

Microcomputer Usage at the Community College Level in the State of Kansas.

ERIC Educational Resources Information Center

Leite, Pedro T.

In spring 1992, a study was performed to identify the current use of microcomputers for instruction at community colleges in Kansas. A questionnaire was sent to 20 community colleges, requesting information on subject areas in which computers are used in instruction, types and quantities of computers used, types of operating systems used, use of…

Microcomputer Database Management Systems for Bibliographic Data.

ERIC Educational Resources Information Center

Pollard, Richard

1986-01-01

Discusses criteria for evaluating microcomputer database management systems (DBMS) used for storage and retrieval of bibliographic data. Two popular types of microcomputer DBMS--file management systems and relational database management systems--are evaluated with respect to these criteria. (Author/MBR)

Tibial tunnel aperture irregularity after drilling with 5 reamer designs: a qualitative micro-computed tomography analysis.

PubMed

Geeslin, Andrew G; Jansson, Kyle S; Wijdicks, Coen A; Chapman, Mark A; Fok, Alex S; LaPrade, Robert F

2011-04-01

There is limited information in the literature on comparisons of antegrade versus retrograde reaming techniques and the effect on the creation of anterior cruciate ligament (ACL) tibial tunnel entry and exit apertures. Proximal and distal apertures of ACL tibial tunnels, as created with different reamers, will be affected by type of reamer design. Controlled laboratory study. Forty skeletally mature porcine tibias with bone mineral density values comparable with a young athletic population were included in this study. Five 9-mm reamer models were used (3 antegrade: A1, smooth-bore reamer; A2, acorn-head reamer; A3, flat-head reamer; 2 retrograde: R1, retrograde acorn reamer; R2, single-blade retrograde reamer), and a new reamer was used for each tibia (8 reamer-tibia pairs per reamer model). All specimens underwent micro-computed tomography scanning, and images were reconstructed and analyzed using 3-dimensional image analysis software. Aperture rim fractures were graded on a 0-IV scale that described the proportion of the fractured aperture circumference. Specimens with incomplete apertures were also recorded. Because of the unique characteristics of various tunnels, intratunnel characteristics were observed and recorded. In sum, 1 proximal and 7 distal aperture rim fractures were found; 3, 0, and 4 distal aperture rim fractures were found with groups A1, A2, and A3, respectively. Incomplete apertures were more commonly found at the distal aperture (n = 15) than the proximal aperture (n = 8); there were no tibias with this finding at both apertures. All incomplete distal apertures occurred with the retrograde technique, and all incomplete proximal apertures occurred with the antegrade technique, most commonly with reamer design A3. An added finding of tunnel curvature at the distal aspect of the tunnel was observed in all 8 tibias with R1 reamers and 5 tibias with R2 reamers. This phenomenon was not observed in any of the tibias reamed with the antegrade technique. Anterior cruciate ligament tibial tunnel aperture characteristics were highly dependent on reamer design. Optimal proximal aperture characteristics were produced by the retrograde reamers, whereas optimal distal aperture characteristics were obtained with the antegrade reamers. In addition, a phenomenon of tunnel curvature in retrograde-type reamers was found, which may have effects on ACL graft or screw fixation. Differences in tunnel aperture shapes and fractures depend on reamer design. This information is important for the creation of ACL reconstruction tunnels with different reamer designs.

Computer Series, 67: Bits and Pieces, 27.

ERIC Educational Resources Information Center

Moore, John W., Ed.

1986-01-01

Discusses a computer interfacing course using Commodore 64 microcomputers; a computer program for radioactive equilibrium; analysis of near infrared spectrum of hydrochloric acid molecules using Apple II microcomputers; microcomputer approach to conductivity titrations; balancing equations with Commodore 64's; formulation of mathematical…

The 4th R: Reasoning.

ERIC Educational Resources Information Center

Miles, Curtis

1983-01-01

Reviews sources of information on materials for teaching reasoning with a microcomputer. Suggests microcomputer magazines, catalogs of commercial materials, CONDUIT (a nonprofit organization devoted to educational computer use), and local microcomputer users groups. Lists Apple II software for strategy games with reasoning applications. (DMM)

Elucidation of the internal physical and chemical microstructure of pharmaceutical granules using X-ray micro-computed tomography, Raman microscopy and infrared spectroscopy.

PubMed

Crean, Barry; Parker, Andrew; Roux, Delphine Le; Perkins, Mark; Luk, Shen Y; Banks, Simon R; Melia, Colin D; Roberts, Clive J

2010-11-01

X-ray micro-computed tomography (XMCT) was used in conjunction with confocal Raman mapping to measure the intra-granular pore size, binder volumes and to provide spatial and chemical maps of internal granular components in α-lactose monohydrate granules formulated with different molecular weights of polyvinyl pyrrolidone (PVP). Infrared spectroscopy was used to understand the molecular association of binder domains. Granules were prepared by high-shear aqueous granulation from α-lactose monohydrate and PVP K29/32 or K90. XMCT was used to visualise the granule microstructure, intra-granular binder distribution and measure intra-granular porosity, which was subsequently related to intrusion porosimetry measurements. Confocal Raman microscopy and infrared microscopy were employed to investigate the distribution of components within the granule and explore the nature of binder substrate interactions. XMCT data sets of internal granule microstructure provided values of residual porosity in the lactose:PVP K29/32 and lactose:PVP K90 granules of 32.41 ± 4.60% and 22.40 ± 0.03%, respectively. The binder volumes of the lactose:PVP K29/32 and lactose:PVP K90 granules were 2.98 ± 0.10% and 3.38 ± 0.07%, respectively, and were attributed to PVP-rich binder domains within the granule. Confocal Raman microscopy revealed anisotropic domains of PVP between 2 μm and 20 μm in size surrounded by larger particles of lactose, in both granule types. Raman data showed that PVP domains contained various amounts of lactose, whilst IR microscopy determined that the PVP was molecularly associated with lactose, rather than residual water. The work shows that XMCT can be applied to investigate granular microstructure and resolve the porosity and the excipient and binder volumes. Combining this technique with vibrational techniques provides further structural information and aids the interpretations of the XMCT images. When used complementarily, these techniques highlighted that porosity and binder volume were the most significant microstructural differences between the α-lactose monohydrate granules formulated with the different grades of PVP. Copyright © 2010 Elsevier B.V. All rights reserved.

Characterization of Dilatant Shear Bands in Castlegate Sandstone Using Micro-Computed Tomography

NASA Astrophysics Data System (ADS)

Rosenthal, R. E.; Issen, K. A.; Richards, M. C.; Ingraham, M. D.

2016-12-01

Deformation bands in granular rock are thin tabular zones of localized shear and/or volumetric strain, which affect permeability and can impact fluid flow, extraction and storage. The present work characterizes dilatant shear bands formed in Castlegate sandstone (a high porosity reservoir analog) during true triaxial laboratory testing (Ingraham et al., 2013a) at low mean stresses. X-ray micro-computed tomography (micro-CT) scans produced 3-dimensional voxel files containing density information of tested specimens. Micro-CT data were thresholded to extract the least dense voxels, corresponding to pore space and localized dilation. Plane fits were determined by a custom algorithm that calculated the angle between the band normal and maximum compression direction. For tests at the same mean stress, the band angle is lower when intermediate principal stress approaches minimum compression and higher when it approaches maximum compression. Micro-CT band angles were compared to angles from the specimen jackets (Ingraham et al., 2013a), and band angles from plane fits through located acoustic emissions (AE) events (Ingraham et al. 2013b). For non-axisymmetric stress states (three unique principal stresses), one primary dilatant shear band formed in each specimen. Occasionally, secondary bands traversing part of the specimen were also identified. The principal band angles from the micro-CT scans were on average within 3 degrees of the jacket angles and within 9 degrees of AE angles. For axisymmetric stress states (intermediate principal stress equal to maximum or minimum compression) micro-CT results reveal multiple conjugate and/or parallel bands. Each jacket angle correlated to a micro-CT angle within 4 degrees. Micro-CT results also reveal that, regardless of stress state, each band is comprised of a network of interconnected pore space pathways meandering between grain clusters, as opposed to an opening fracture/joint. Ingraham MD, KA Issen, DJ Holcomb, 2013a, J. Geophys. Res. Solid Earth, Vol. 118, pp. 536-552, doi:10.1002/jgrb.50084. Ingraham MD, KA Issen, DJ Holcomb, 2013b, Acta Geotech., Vol. 8, Iss. 6, pp. 645-663, DOI: 10.1007/s11440-013-0275-y.

Ambient occlusion - A powerful algorithm to segment shell and skeletal intrapores in computed tomography data

NASA Astrophysics Data System (ADS)

Titschack, J.; Baum, D.; Matsuyama, K.; Boos, K.; Färber, C.; Kahl, W.-A.; Ehrig, K.; Meinel, D.; Soriano, C.; Stock, S. R.

2018-06-01

During the last decades, X-ray (micro-)computed tomography has gained increasing attention for the description of porous skeletal and shell structures of various organism groups. However, their quantitative analysis is often hampered by the difficulty to discriminate cavities and pores within the object from the surrounding region. Herein, we test the ambient occlusion (AO) algorithm and newly implemented optimisations for the segmentation of cavities (implemented in the software Amira). The segmentation accuracy is evaluated as a function of (i) changes in the ray length input variable, and (ii) the usage of AO (scalar) field and other AO-derived (scalar) fields. The results clearly indicate that the AO field itself outperforms all other AO-derived fields in terms of segmentation accuracy and robustness against variations in the ray length input variable. The newly implemented optimisations improved the AO field-based segmentation only slightly, while the segmentations based on the AO-derived fields improved considerably. Additionally, we evaluated the potential of the AO field and AO-derived fields for the separation and classification of cavities as well as skeletal structures by comparing them with commonly used distance-map-based segmentations. For this, we tested the zooid separation within a bryozoan colony, the stereom classification of an ophiuroid tooth, the separation of bioerosion traces within a marble block and the calice (central cavity)-pore separation within a dendrophyllid coral. The obtained results clearly indicate that the ideal input field depends on the three-dimensional morphology of the object of interest. The segmentations based on the AO-derived fields often provided cavity separations and skeleton classifications that were superior to or impossible to obtain with commonly used distance-map-based segmentations. The combined usage of various AO-derived fields by supervised or unsupervised segmentation algorithms might provide a promising target for future research to further improve the results for this kind of high-end data segmentation and classification. Furthermore, the application of the developed segmentation algorithm is not restricted to X-ray (micro-)computed tomographic data but may potentially be useful for the segmentation of 3D volume data from other sources.

Micro-computed tomography analysis of post space preparation in root canals filled with carrier-based thermoplasticized gutta-percha.

PubMed

Schroeder, A A; Ford, N L; Coil, J M

2017-03-01

To determine whether post space preparation deviated from the root canal preparation in canals filled with Thermafil, GuttaCore or warm vertically compacted gutta-percha. Forty-two extracted human permanent maxillary lateral incisors were decoronated, and their root canals instrumented using a standardized protocol. Samples were divided into three groups and filled with Thermafil (Dentsply Tulsa Dental Specialties, Johnson City, TN, USA), GuttaCore (Dentsply Tulsa Dental Specialties) or warm vertically compacted gutta-percha, before post space preparation was performed with a GT Post drill (Dentsply Tulsa Dental Specialties). Teeth were scanned using micro-computed tomography after root filling and again after post space preparation. Scans were examined for number of samples with post space deviation, linear deviation of post space preparation and minimum root thickness before and after post space preparation. Parametric data were analysed with one-way analysis of variance (anova) or one-tailed paired Student's t-tests, whilst nonparametric data were analysed with Fisher's exact test. Deviation occurred in eight of forty-two teeth (19%), seven of fourteen from the Thermafil group (50%), one of fourteen from the GuttaCore group (7%), and none from the gutta-percha group. Deviation occurred significantly more often in the Thermafil group than in each of the other two groups (P < 0.05). Linear deviation of post space preparation was greater in the Thermafil group than in both of the other groups and was significantly greater than that of the gutta-percha group (P < 0.05). Minimum root thickness before post space preparation was significantly greater than it was after post space preparation for all groups (P < 0.01). The differences between the Thermafil, GuttaCore and gutta-percha groups in the number of samples with post space deviation and in linear deviation of post space preparation were associated with the presence or absence of a carrier as well as the different carrier materials. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Microcomputer Competencies for Vocational Teachers.

ERIC Educational Resources Information Center

Roth, Gene L.; Tesolowski, Dennis G.

1984-01-01

This joint research and development project of two state departments of education used the DACUM (Developing a Curriculum) process to identify microcomputer competencies for vocational instructors. Brainstorming techniques were used to identify five categories of microcomputer applications and to determine which competencies belonged in each…

Modeling with Microcomputers.

ERIC Educational Resources Information Center

Litaker, R. Gregory

The applications of a recently developed computer program for microcomputers in developing models in an institutional research environment are considered. The VISICALC program requires no user programming skills, is available for all major brands of microcomputers, and provides for easy exchange of information between users of different computing…

Measuring Thermoelectric Properties Automatically

NASA Technical Reports Server (NTRS)

Chmielewski, A.; Wood, C.

1986-01-01

Microcomputer-controlled system speeds up measurements of Hall voltage, Seebeck coefficient, and thermal diffusivity in semiconductor compounds for thermoelectric-generator applications. With microcomputer system, large data base of these parameters gathered over wide temperature range. Microcomputer increases measurement accuracy, improves operator productivity, and reduces test time.

Microcomputers, Evaluation, Literacy: Will the Teacher Survive?

ERIC Educational Resources Information Center

Hofmann, Richard J., Ed.

1982-01-01

The development of computer technology is considered, the concept of computer literacy is defined, and the role of teachers in educational microcomputer programs is discussed. The field of commercially produced software for microcomputers is reviewed. (For related articles, see EC 142 959-962.) (Author)

Implementing a Microcomputer Database Management System.

ERIC Educational Resources Information Center

Manock, John J.; Crater, K. Lynne

1985-01-01

Current issues in selecting, structuring, and implementing microcomputer database management systems in research administration offices are discussed, and their capabilities are illustrated with the system used by the University of North Carolina at Wilmington. Trends in microcomputer technology and their likely impact on research administration…

Single-chip microcomputer application in high-altitude balloon orientation system

NASA Technical Reports Server (NTRS)

Lim, T. S.; Ehrmann, C. H.; Allison, S. R.

1980-01-01

This paper describes the application of a single-chip microcomputer in a high-altitude balloon instrumentation system. The system, consisting of a magnetometer, a stepping motor, a microcomputer and a gray code shaft encoder, is used to provide an orientation reference to point a scientific instrument at an object in space. The single-chip microcomputer, Intel's 8748, consisting of a CPU, program memory, data memory and I/O ports, is used to control the orientation of the system.

Bi-directional communication interface for microprocessor-to-system/370

NASA Technical Reports Server (NTRS)

Fischer, J. P.

1981-01-01

The design and operation of a bi-directional communication interface between a microcomputer and the IBM System/370 is documented. The hardware unit interconnects a modem to interface to the S/370, the microcomputer with an EIA I/O port, and a terminal for sending and receiving data from either the microcomputer or the S/370. Also described is the software necessary for the two-way interface. This interface is designed so that no modifications need to be made to the terminal, modem, or microcomputer.

Designing a User-Friendly Microcomputer-Based Laboratory Package through the Factor Analysis of Teacher Evaluations

ERIC Educational Resources Information Center

Lavonen, Jari; Juuti, Kalle; Meisalo, Veijo

2003-01-01

In this study we analyse how the experiences of chemistry teachers on the use of a Microcomputer-Based Laboratory (MBL), gathered by a Likert-scale instrument, can be utilized to develop the new package "Empirica 2000." We used exploratory factor analysis to identify the essential features in a large set of questionnaire data to see how…

The Role of Microcomputer-Based Laboratories in Learning To Make Graphs of Distance and Velocity.

ERIC Educational Resources Information Center

Brasell, Heather

Two questions about the effects of microcomputer-based laboratory (MBL) activities on graphing skills were addressed in this study: (1) the extent to which activities help students link their concrete experiences with motion with graphic representations of these experiences; and (2) the degree of importance of the real-time aspect of the MBL in…

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION AND MAINTENANCE OF THE LAN AND RELATED MICROCOMPUTER ENVIRONMENT (UA-D-1.1)

EPA Science Inventory

The purpose of this SOP is to describe procedures for using and maintaining the local area network (LAN) and related microcomputer equipment at the HRP Site of the Arizona Prevention Center. These methods were used for all data operations and maintenance routines during the Ariz...

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION AND MAINTENANCE OF THE LAN AND RELATED MICROCOMPUTER ENVIRONMENT (UA-D-1.1)

EPA Science Inventory

The purpose of this SOP is to describe procedures for using and maintaining the local area network (LAN) and related microcomputer equipment at the Health Related Professions site at the University of Arizona. These methods were used for all data operations and maintenance routi...

Gold nanorods as a theranostic platform for in vitro and in vivo imaging and photothermal therapy of inflammatory macrophages

NASA Astrophysics Data System (ADS)

Qin, Jinbao; Peng, Zhiyou; Li, Bo; Ye, Kaichuang; Zhang, Yuxin; Yuan, Fukang; Yang, Xinrui; Huang, Lijia; Hu, Junqing; Lu, Xinwu

2015-08-01

Inflammatory macrophages play pivotal roles in the development of atherosclerosis. Theranostics, a promising approach for local imaging and photothermal therapy of inflammatory macrophages, has drawn increasing attention in biomedical research. In this study, gold nanorods (Au NRs) were synthesized, and their in vitro photothermal effects on the macrophage cell line (Ana-1 cells) under 808 nm near infrared reflection (NIR) were investigated by the CCK8 assay, calcein AM/PI staining, flow cytometry, transmission electron microscopy (TEM), silver staining and in vitro micro-computed tomography (CT) imaging. These Au NRs were then applied to an apolipoprotein E knockout (Apo E) mouse model to evaluate their effects on in vivo CT imaging and their effectiveness as for the subsequent photothermal therapy of macrophages in femoral artery restenosis under 808 nm laser irradiation. In vitro photothermal ablation treatment using Au NRs exhibited a significant cell-killing efficacy of macrophages, even at relatively low concentrations of Au NRs and low NIR powers. In addition, the in vivo results demonstrated that the Au NRs are effective for in vivo imaging and photothermal therapy of inflammatory macrophages in femoral artery restenosis. This study shows that Au nanorods are a promising theranostic platform for the diagnosis and photothermal therapy of inflammation-associated diseases.Inflammatory macrophages play pivotal roles in the development of atherosclerosis. Theranostics, a promising approach for local imaging and photothermal therapy of inflammatory macrophages, has drawn increasing attention in biomedical research. In this study, gold nanorods (Au NRs) were synthesized, and their in vitro photothermal effects on the macrophage cell line (Ana-1 cells) under 808 nm near infrared reflection (NIR) were investigated by the CCK8 assay, calcein AM/PI staining, flow cytometry, transmission electron microscopy (TEM), silver staining and in vitro micro-computed tomography (CT) imaging. These Au NRs were then applied to an apolipoprotein E knockout (Apo E) mouse model to evaluate their effects on in vivo CT imaging and their effectiveness as for the subsequent photothermal therapy of macrophages in femoral artery restenosis under 808 nm laser irradiation. In vitro photothermal ablation treatment using Au NRs exhibited a significant cell-killing efficacy of macrophages, even at relatively low concentrations of Au NRs and low NIR powers. In addition, the in vivo results demonstrated that the Au NRs are effective for in vivo imaging and photothermal therapy of inflammatory macrophages in femoral artery restenosis. This study shows that Au nanorods are a promising theranostic platform for the diagnosis and photothermal therapy of inflammation-associated diseases. Electronic supplementary information (ESI) available: Figures. See DOI: 10.1039/c5nr02521d

The Administrator's Use of Microcomputer Systems.

ERIC Educational Resources Information Center

Brown, Kenneth C.

1983-01-01

The use of microcomputers by college administrators to increase productivity is discussed. Microcomputers can help increase productivity in the following administrative office tasks: decision support, communication, personal assistance, and task management. One of the most promising developments to emerge from the decision sciences over the past…

Trend Analysis Using Microcomputers.

ERIC Educational Resources Information Center

Berger, Carl F.

A trend analysis statistical package and additional programs for the Apple microcomputer are presented. They illustrate strategies of data analysis suitable to the graphics and processing capabilities of the microcomputer. The programs analyze data sets using examples of: (1) analysis of variance with multiple linear regression; (2) exponential…

Using the Microcomputer to Develop Listening Skills.

ERIC Educational Resources Information Center

Mohler, Stephen C.

A college-level introductory Spanish instructional system uses an interactive combination of microcomputer and program-stop tape recorder to enhance students' listening skills. The basic content is listening drills, adapted to the computer medium. Microcomputer use adds considerable versatility to instructional materials, including such features…

Increasing Productivity with Microcomputers: Key to Improvement of Special Educattion in the 1980s.

ERIC Educational Resources Information Center

Brady, Richard C.; Dodge, Bernard J.

1982-01-01

Five microcomputer applications which may improve the management of teacher education programs are noted (database management, word processing, spread sheets, project scheduling and management, and test scoring), and six steps in introducing microcomputers into a department are discussed. (CL)

Triamcinolone acetonide activates an anti-inflammatory and folate receptor-positive macrophage that prevents osteophytosis in vivo.

PubMed

Siebelt, Michiel; Korthagen, Nicoline; Wei, Wu; Groen, Harald; Bastiaansen-Jenniskens, Yvonne; Müller, Christina; Waarsing, Jan Hendrik; de Jong, Marion; Weinans, Harrie

2015-12-05

Triamcinolone acetonide (TA) is used for osteoarthritis management to reduce pain, and pre-clinical studies have shown that TA limits osteophyte formation. Osteophyte formation is known to be facilitated by synovial macrophage activation. TA injections might influence macrophage activation and subsequently reduce osteophytosis. Although widely applied in clinical care, the mechanism through which TA exerts this effect remains unknown. In this animal study, we investigated the in vivo effects of TA injections on macrophage activation, osteophyte development and joint degeneration. Furthermore, in vitro macrophage differentiation experiments were conducted to further explain working mechanisms of TA effects found in vivo. Osteoarthritis was induced in rat knees using papain injections and a running protocol. Untreated and TA-treated animals were longitudinally monitored for 12 weeks with in vivo micro-computed tomography (μCT) to measure subchondral bone changes. Synovial macrophage activation was measured in vivo using folate receptor β (FRβ)-targeted single-photon emission computed tomography/computed tomography. Articular cartilage was analyzed at 6 and 12 weeks with ex vivo contrast-enhanced μCT and histology. To further explain the outcomes of our in vivo study, TA on macrophages was also studied in vitro. These cultured macrophages were either M1- or M2-activated, and they were analyzed using fluorescence-activated cell sorting for CD163 and FRβ expression as well as for messenger RNA (mRNA) expression of interleukin (IL)-10. Our in vivo study showed that intra-articular injections with TA strongly enhanced FRβ(+) macrophage activation. Despite stimulated macrophage activation, osteophyte formation was fully prevented. There was no beneficial effect of TA against cartilage degradation or subchondral bone sclerosis. In vitro macrophage cultures showed that TA strongly induced monocyte differentiation towards CD163(+) and FRβ(+) macrophages. Furthermore, TA-stimulated M2 macrophages showed enhanced IL-10 expression at the mRNA level. TA injections potently induce a CD163(+)- and FRβ(+)-activated macrophage with anti-inflammatory characteristics such as reduced IL-10 production in vitro and lack of osteophytosis in vivo.

The Evolution and Development of Cephalopod Chambers and Their Shape

PubMed Central

Lemanis, Robert; Korn, Dieter; Zachow, Stefan; Rybacki, Erik; Hoffmann, René

2016-01-01

The Ammonoidea is a group of extinct cephalopods ideal to study evolution through deep time. The evolution of the planispiral shell and complexly folded septa in ammonoids has been thought to have increased the functional surface area of the chambers permitting enhanced metabolic functions such as: chamber emptying, rate of mineralization and increased growth rates throughout ontogeny. Using nano-computed tomography and synchrotron radiation based micro-computed tomography, we present the first study of ontogenetic changes in surface area to volume ratios in the phragmocone chambers of several phylogenetically distant ammonoids and extant cephalopods. Contrary to the initial hypothesis, ammonoids do not possess a persistently high relative chamber surface area. Instead, the functional surface area of the chambers is higher in earliest ontogeny when compared to Spirula spirula. The higher the functional surface area the quicker the potential emptying rate of the chamber; quicker chamber emptying rates would theoretically permit faster growth. This is supported by the persistently higher siphuncular surface area to chamber volume ratio we collected for the ammonite Amauroceras sp. compared to either S. spirula or nautilids. We demonstrate that the curvature of the surface of the chamber increases with greater septal complexity increasing the potential refilling rates. We further show a unique relationship between ammonoid chamber shape and size that does not exist in S. spirula or nautilids. This view of chamber function also has implications for the evolution of the internal shell of coleoids, relating this event to the decoupling of soft-body growth and shell growth. PMID:26963712

Microcomputers and Informatics Education at the University Level.

ERIC Educational Resources Information Center

Boyanov, Todor

1984-01-01

Because of the widespread use of microcomputers in Bulgaria, informatics education for all college students is considered both possible and necessary. Uses of microcomputers in various disciplines are described, including those in mathematics/mechanics, the experimental sciences, and humanities. Brief comments on computer-assisted-learning and…

Microcomputers: Software Evaluation. Evaluation Guides. Guide Number 17.

ERIC Educational Resources Information Center

Gray, Peter J.

This guide discusses three critical steps in selecting microcomputer software and hardware: setting the context, software evaluation, and managing microcomputer use. Specific topics addressed include: (1) conducting an informal task analysis to determine how the potential user's time is spent; (2) identifying tasks amenable to computerization and…

Microcomputers in Higher Education.

ERIC Educational Resources Information Center

McLean, Robert S., Ed.; McLean, Ruth W., Ed.

1981-01-01

Some of the areas in which Ontario educators currently employ microcomputers in higher education are addressed in several articles, bibliographies, and book reviews. Various uses of computer-managed instruction and computer-assisted instruction (CAI) at Humber College of Applied Arts and Technology are outlined by Frank A. Ford. Microcomputer CAI…

The Integration of Microcomputers into the Classroom or Now That I've Got It, What Do I Do with It?

ERIC Educational Resources Information Center

Keyser, Earl L.

1979-01-01

Provides a few examples of the use of the microcomputer in the classroom, emphasizing the advantages of the small machine. Notes the availability of tools to create instructional materials on the microcomputer. (Author/IRT)

Administrative Uses of Microcomputers.

ERIC Educational Resources Information Center

Crawford, Chase

1987-01-01

This paper examines the administrative uses of the microcomputer, stating that high performance educational managers are likely to have microcomputers in their organizations. Four situations that would justify the use of a computer are: (1) when massive amounts of data are processed through well-defined operations; (2) when data processing is…

The Microcomputer and Instruction in Geometry.

ERIC Educational Resources Information Center

Kantowski, Mary Grace

1981-01-01

The microcomputer has great potential for making high school geometry more stimulating and more easily understood by the students. The microcomputer can facilitate instruction in both the logico-deductive and spatial-visual aspects of geometry through graphics representations, simulation of motion, and its capability of interacting with the…

Determination of strain fields in porous shape memory alloys using micro-computed tomography

NASA Astrophysics Data System (ADS)

Bormann, Therese; Friess, Sebastian; de Wild, Michael; Schumacher, Ralf; Schulz, Georg; Müller, Bert

2010-09-01

Shape memory alloys (SMAs) belong to 'intelligent' materials since the metal alloy can change its macroscopic shape as the result of the temperature-induced, reversible martensite-austenite phase transition. SMAs are often applied for medical applications such as stents, hinge-less instruments, artificial muscles, and dental braces. Rapid prototyping techniques, including selective laser melting (SLM), allow fabricating complex porous SMA microstructures. In the present study, the macroscopic shape changes of the SMA test structures fabricated by SLM have been investigated by means of micro computed tomography (μCT). For this purpose, the SMA structures are placed into the heating stage of the μCT system SkyScan 1172™ (SkyScan, Kontich, Belgium) to acquire three-dimensional datasets above and below the transition temperature, i.e. at room temperature and at about 80°C, respectively. The two datasets were registered on the basis of an affine registration algorithm with nine independent parameters - three for the translation, three for the rotation and three for the scaling in orthogonal directions. Essentially, the scaling parameters characterize the macroscopic deformation of the SMA structure of interest. Furthermore, applying the non-rigid registration algorithm, the three-dimensional strain field of the SMA structure on the micrometer scale comes to light. The strain fields obtained will serve for the optimization of the SLM-process and, more important, of the design of the complex shaped SMA structures for tissue engineering and medical implants.

Influence of Alveolar Bone Defects on the Stress Distribution in Quad Zygomatic Implant-Supported Maxillary Prosthesis.

PubMed

Duan, Yuanyuan; Chandran, Ravi; Cherry, Denise

The purpose of this study was to create three-dimensional composite models of quad zygomatic implant-supported maxillary prostheses with a variety of alveolar bone defects around implant sites, and to investigate the stress distribution in the surrounding bone using the finite element analysis (FEA) method. Three-dimensional models of titanium zygomatic implants, maxillary prostheses, and human skulls were created and assembled using Mimics based on microcomputed tomography and cone beam computed tomography images. A variety of additional bone defects were created at the locations of four zygomatic implants to simulate multiple clinical scenarios. The volume meshes were created and exported into FEA software. Material properties were assigned respectively for all the structures, and von Mises stress data were collected and plotted in the postprocessing module. The maximum stress in the surrounding bone was located in the crestal bone around zygomatic implants. The maximum stress in the prostheses was located at the angled area of the implant-abutment connection. The model with anterior defects had a higher peak stress value than the model with posterior defects. All the models with additional bone defects had higher maximum stress values than the control model without additional bone loss. Additional alveolar bone loss has a negative influence on the stress concentration in the surrounding bone of quad zygomatic implant-supported prostheses. More care should be taken if these additional bone defects are at the sites of anterior zygomatic implants.

Flow perfusion culture of MC3T3-E1 osteogenic cells on gradient calcium polyphosphate scaffolds with different pore sizes.

PubMed

Chen, Liang; Song, Wei; Markel, David C; Shi, Tong; Muzik, Otto; Matthew, Howard; Ren, Weiping

2016-02-01

Calcium polyphosphate is a biodegradable bone substitute. It remains a challenge to prepare porous calcium polyphosphate with desired gradient porous structures. In this study, a modified one-step gravity sintering method was used to prepare calcium polyphosphate scaffolds with desired-gradient-pore-size distribution. The differences of porous structure, mechanical strength, and degradation rate between gradient and homogenous calcium polyphosphate scaffolds were evaluated by micro-computed tomography, scanning electron microscopy, and mechanical testing. Preosteoblastic MC3T3-E1 cells were seeded onto gradient and homogenous calcium polyphosphate scaffolds and cultured in a flow perfusion bioreactor. The distribution, proliferation, and differentiation of the MC3T3-E1 cells were compared to that of homogenous calcium polyphosphate scaffolds. Though no significant difference of cell proliferation was found between the gradient and the homogenous calcium polyphosphate scaffolds, a much higher cell differentiation and mineralization were observed in the gradient calcium polyphosphate scaffolds than that of the homogenous calcium polyphosphate scaffolds, as manifested by increased alkaline phosphatase activity (p < 0.05). The improved distribution and differentiation of cultured cells within gradient scaffolds were further supported by both (18)F-fluorine micro-positron emission tomography scanning and in vitro tetracycline labeling. We conclude that the calcium polyphosphate scaffold with gradient pore sizes enhances osteogenic cell differentiation as well as mineralization. The in vivo performance of gradient calcium polyphosphate scaffolds warrants further investigation in animal bone defect models. © The Author(s) 2015.

Microcomputers in the Learning Center: Guidelines for Avoiding Costly Mistakes.

ERIC Educational Resources Information Center

Belair, Charles

Guidelines for the planning and purchase of microcomputer systems are presented in outline form. These guidelines are directed to educators in developmental education, special education, and learning center environments; however, they are applicable to all educators intending to use microcomputers. First, a discussion of hardware considerations is…

Using Microcomputers in Teaching Vocational Agriculture.

ERIC Educational Resources Information Center

Barrick, R. Kirby, Ed.

This collection of articles is designed to help vocational agriculture teachers use microcomputers in teaching. The guide covers both the different types of software and the ways they can be applied in teaching. The guide is organized in three sections. The first section covers types of programs and includes "Selection of Microcomputer Hardware…

Automating Relational Database Design for Microcomputer Users.

ERIC Educational Resources Information Center

Pu, Hao-Che

1991-01-01

Discusses issues involved in automating the relational database design process for microcomputer users and presents a prototype of a microcomputer-based system (RA, Relation Assistant) that is based on expert systems technology and helps avoid database maintenance problems. Relational database design is explained and the importance of easy input…

Microcomputers in Education. Report No. 4798.

ERIC Educational Resources Information Center

Feurzeig, W.; And Others

A brief review of the history of computer-assisted instruction and discussion of the current and potential roles of microcomputers in education introduce this review of the capabilities of state-of-the-art microcomputers and currently available software for them, and some speculations about future trends and developments. A survey of current…

The Use of Portable Microcomputers to Collect Student and Teacher Behavior Data.

ERIC Educational Resources Information Center

Rieth, Herbert; And Others

1989-01-01

Using portable microcomputers, three applications programs were developed and implemented to collect, store, transmit, and analyze teacher/student observational data. The three applications involved: analyzing teaching behaviors of trainees in field-site placements, using microcomputers to educate mildly handicapped high-school students, and using…

Microcomputer & Software Use in Michigan's Vocational-Technical Facilities: A Status Report.

ERIC Educational Resources Information Center

Harris, Richard

This report is intended to help Michigan's vocational and technical teachers and administrators make decisions regarding the purchase of microcomputer hardware and software for professional use. Addressed in a discussion of computer hardware are current and planned inventories of microcomputer hardware located in the public vocational and…

The Microcomputer Revolution.

ERIC Educational Resources Information Center

Kinne, Harold C.

The history of the development of the microcomputer industry since its inception in 1975 is explored in this brief paper, which pays special attention to the advent of the small business computer. The author describes the growth of sales, the development of successful companies, the early resistance to use of microcomputers in business, and the…

The Use of Microcomputers in Distance Teaching Systems. ZIFF Papiere 70.

ERIC Educational Resources Information Center

Rumble, Greville

Microcomputers have revolutionized distance education in virtually every area. Used alone, personal computers provide students with a wide range of utilities, including word processing, graphics packages, and spreadsheets. When linked to a mainframe computer or connected to other personal computers in local area networks, microcomputers can…

Microcomputer Software Programs for Vocational Education.

ERIC Educational Resources Information Center

Rodenstein, Judith, Ed.; Lambert, Roger, Ed.

Over 200 microcomputer software packages applicable to vocational education are listed. Most of the programs are available for the Apple, TRS-80, and Commodore microcomputers. The packages have been reviewed, but have not been formally evaluated. Titles of the programs with names and addresses of the distributors are provided. Telephone numbers…

Tools of the Trade: Microcomputer-Based Instrumentation: As Easy As ADC.

ERIC Educational Resources Information Center

Lam, Tom

1983-01-01

Provides a brief introduction to using the microcomputer as a piece of laboratory equipment. Focuses on the range of hardware currently available to assist microcomputer-based-instrumentation (MBI), specifically the analog-to-digital converters. In addition, discusses specification of system performance, selection and integration of components,…

Using Microcomputers Interactively in Large Classrooms.

ERIC Educational Resources Information Center

Bowman, Barbara E.; Ellsworth, Randy

In 1980, Wichita State University received a grant to introduce microcomputers as interactive teaching tools in large science classrooms. Through this grant, 18 faculty in 11 departments developed software modules illustrating concepts that are often difficult to teach by usual lecture methods. To determine whether the use of microcomputers in…

Microcomputers in Education: A Self-Paced Orientation.

ERIC Educational Resources Information Center

Carey, Doris; Carey, Regan

Designed to serve as a self-paced computer course for education students with no experience using microcomputers, this manual contains instructions for operating an Apple IIe microcomputer, its introductory software, and Bank Street Writer, using the DOS 3.3 System Master. The lessons, which contain illustrations and sample screens, include…

Word/Information Processing with Microcomputers in Business Education. Final Narrative Report for the Exemplary Project.

ERIC Educational Resources Information Center

Ascension Parish School Board, Donaldsonville, LA.

This demonstration introduced microcomputers into St. Amant High School in Louisiana by instituting a word/information processing program. Microcomputers, printers, and necessary software were purchased, and the manufacturer's educational representative instructed the word/information processing teacher on the operation of the equipment. The…

Microcomputer Usage in Schools, 1984-1985.

ERIC Educational Resources Information Center

Quality Education Data, Inc., Denver, CO.

Results are presented for the fourth annual survey of all U.S. school districts by Quality Educational Data, Inc. Findings are displayed in tabular form and include information on the following: market penetration by major brands of microcomputers in school districts and buildings; school districts that use microcomputers and the brand or…

48 CFR 1552.239-103 - Acquisition of Energy Star Compliant Microcomputers, Including Personal Computers, Monitors and...

Code of Federal Regulations, 2012 CFR

2012-10-01

... Compliant Microcomputers, Including Personal Computers, Monitors and Printers. 1552.239-103 Section 1552.239... Star Compliant Microcomputers, Including Personal Computers, Monitors and Printers. As prescribed in... Personal Computers, Monitors, and Printers (APR 1996) (a) The Contractor shall provide computer products...

Multiple-User Microcomputer Technology and Its Application to the Library Environment.

ERIC Educational Resources Information Center

McCarthy, Cathleen D.

1987-01-01

Demonstrates the ways in which multiuser and multitasking microcomputer systems can be used for the automation of small- to medium-sized library operations. The possibilities afforded by the IBM-PC AT microcomputer are discussed and a sample configuration with estimated cost projections is provided. (EM)

Microcomputers: Applications in Vocational Education.

ERIC Educational Resources Information Center

Rodenstein, Judith, Ed.; Lambert, Roger, Ed.

This handbook was assembled for vocational educators so that they can see the applications of microcomputers in both their instructional and administrative tasks. The 22 papers included in the handbook were written by educators who are and have been using microcomputers extensively in their work. The first section of the handbook discusses the…

Microcomputer Applications for Teaching Microeconomic Concepts: Some Old and New Approaches.

ERIC Educational Resources Information Center

Smith, L. Murphy; Smith, L. C., Jr.

1989-01-01

Presents microcomputer programs and programing techniques and demonstrates how these programs can be used by teachers to explain economics concepts and to help students make judgments. Each microcomputer application is supplemented by traditional graphic and mathematical analysis. Discusses applications dealing with supply, demand, elasticity,…

Information Resources on Microcomputers in Libraries: Public Services. A Selected ERIC Bibliography.

ERIC Educational Resources Information Center

ERIC Clearinghouse on Information Resources, Syracuse, NY.

Twelve articles published between 1982 and 1984 and cited in "Current Index to Journals in Education" are listed in this bibliography on public service applications of microcomputers in libraries. Topics include provision of free public access to microcomputers (justification, objectives, equipment specifications, uses and software,…

48 CFR 1552.239-103 - Acquisition of Energy Star Compliant Microcomputers, Including Personal Computers, Monitors and...

Code of Federal Regulations, 2011 CFR

2011-10-01

... Compliant Microcomputers, Including Personal Computers, Monitors and Printers. 1552.239-103 Section 1552.239... Star Compliant Microcomputers, Including Personal Computers, Monitors and Printers. As prescribed in... Personal Computers, Monitors, and Printers (APR 1996) (a) The Contractor shall provide computer products...