X-ray micro-Tomography at the Advanced Light Source

Science.gov (United States)

The X-ray micro-Tomography Facility at the Advanced Light Source has been in operation since 2004. The source is a superconducting bend magnet of critical energy 10.5KeV; photon energy coverage is 8-45 KeV in monochromatic mode, and a filtered white light option yields useful photons up to 50 KeV. A...

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

Science.gov (United States)

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.

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

NARCIS (Netherlands)

Schouten, C.; Meijer, G.J.; Beucken, J.J.J.P van den; Spauwen, P.H.M.; Jansen, J.A.

2009-01-01

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

In vivo quantitative assessment of myocardial structure, function, perfusion and viability using cardiac micro-computed tomography

NARCIS (Netherlands)

E.D. van Deel (Elza); Y. Ridwan (Yanto); van Vliet, J.N. (J. Nicole); Belenkov, S. (Sasha); J. Essers (Jeroen)

2016-01-01

textabstractThe use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most

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

Energy Technology Data Exchange (ETDEWEB)

Acar, Buket; Kamburoglu, Kivanc [Dept. of Dentomaxillofacial Radiology, Faculty of Dentistry, Ankara University, Ankara (Turkmenistan); Tatar, Ilkan [Dept. of Anatomy, Faculty of Medicine, Hacettepe University, Ankara (Turkmenistan); Arikan, Volkan [Dept. of Anatomy, Faculty of Medicine, Hacettepe University, Ankara (Turkmenistan); Celik, Hakan Hamid [Dept. of Pediatric Dentistry, Faculty of Dentistry, Kirikkale Unversity, Ankara (Turkmenistan); Yuksel, Selcen [Dept. of Biostatistics, Faculty of Medicine, Yildirim Beyazit University, Ankara (Turkmenistan); Ozen, Tuncer [Dept. of Dentomaxillofacial Radiology, Gulhane Military Hospital, Dental Clinics, Ankara (Turkmenistan)

2015-12-15

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.

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

International Nuclear Information System (INIS)

Acar, Buket; Kamburoglu, Kivanc; Tatar, Ilkan; Arikan, Volkan; Celik, Hakan Hamid; Yuksel, Selcen; Ozen, Tuncer

2015-01-01

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

Micro computed tomography (CT) scanned anatomical gateway to insect pest bioinformatics

Science.gov (United States)

An international collaboration to establish an interactive Digital Video Library for a Systems Biology Approach to study the Asian citrus Psyllid and psyllid genomics/proteomics interactions is demonstrated. Advances in micro-CT, digital computed tomography (CT) scan uses X-rays to make detailed pic...

First-in-human uPAR PET

DEFF Research Database (Denmark)

Persson, Morten; Skovgaard, Dorthe; Brandt-Larsen, Malene

2015-01-01

A first-in-human clinical trial with Positron Emission Tomography (PET) imaging of the urokinase-type plasminogen activator receptor (uPAR) in patients with breast, prostate and bladder cancer, is described. uPAR is expressed in many types of human cancers and the expression is predictive...... for targeted molecular imaging with PET. The safety, pharmacokinetic, biodistribution profile and radiation dosimetry after a single intravenous dose of (64)Cu-DOTA-AE105 were assessed by serial PET and computed tomography (CT) in 4 prostate, 3 breast and 3 bladder cancer patients. Safety assessment...... of invasion, metastasis and indicates poor prognosis. uPAR PET imaging therefore holds promise to be a new and innovative method for improved cancer diagnosis, staging and individual risk stratification. The uPAR specific peptide AE105 was conjugated to the macrocyclic chelator DOTA and labeled with (64)Cu...

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

Science.gov (United States)

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 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.

X-ray phase-contrast micro-tomography and image analysis of wood microstructure

International Nuclear Information System (INIS)

Mayo, Sheridan; Evans, Robert; Chen, Fiona; Lagerstrom, Ryan

2009-01-01

A number of commercially important properties of wood depend on details of the wood micro- and nano- structure. CSIRO Forest Biosciences have developed SilviScan, an analytical instrument which uses a number of high-speed techniques for analyzing these properties. X-ray micro-tomographic analysis of wood samples provides detailed 3D reconstructions of the wood microstructure which can be used to validate results from SilviScan measurements. A series of wood samples was analysed using laboratory-based phase-contrast x-ray micro-tomography. Image analysis techniques were applied to the 3D data sets to extract significant features and statistical properties of the specimens. These data provide a means of verification of results from the more rapid SilviScan techniques, and will clarify the results of micro-diffraction studies of wood microfibrils.

Nondestructive analysis of urinary calculi using micro computed tomography

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Lingeman James E

2004-12-01

Full Text Available Abstract Background Micro computed tomography (micro CT has been shown to provide exceptionally high quality imaging of the fine structural detail within urinary calculi. We tested the idea that micro CT might also be used to identify the mineral composition of urinary stones non-destructively. Methods Micro CT x-ray attenuation values were measured for mineral that was positively identified by infrared microspectroscopy (FT-IR. To do this, human urinary stones were sectioned with a diamond wire saw. The cut surface was explored by FT-IR and regions of pure mineral were evaluated by micro CT to correlate x-ray attenuation values with mineral content. Additionally, intact stones were imaged with micro CT to visualize internal morphology and map the distribution of specific mineral components in 3-D. Results Micro CT images taken just beneath the cut surface of urinary stones showed excellent resolution of structural detail that could be correlated with structure visible in the optical image mode of FT-IR. Regions of pure mineral were not difficult to find by FT-IR for most stones and such regions could be localized on micro CT images of the cut surface. This was not true, however, for two brushite stones tested; in these, brushite was closely intermixed with calcium oxalate. Micro CT x-ray attenuation values were collected for six minerals that could be found in regions that appeared to be pure, including uric acid (3515 – 4995 micro CT attenuation units, AU, struvite (7242 – 7969 AU, cystine (8619 – 9921 AU, calcium oxalate dihydrate (13815 – 15797 AU, calcium oxalate monohydrate (16297 – 18449 AU, and hydroxyapatite (21144 – 23121 AU. These AU values did not overlap. Analysis of intact stones showed excellent resolution of structural detail and could discriminate multiple mineral types within heterogeneous stones. Conclusions Micro CT gives excellent structural detail of urinary stones, and these results demonstrate the feasibility

Micro-computed tomography newly developed for in vivo small animal imaging

International Nuclear Information System (INIS)

Arai, Yoshinori; Ninomiya, Tadashi; Kato, Takafumi; Masuda, Yuji

2005-01-01

The aim of this paper is to report a newly developed micro-computed tomography system for in vivo use. The system was composed of a micro-focus X-ray tube and an image intensifier (I.I.), both of which rotated around the object stage. A guinea pig and a rat were examined. The anesthetized animal was set on the secure object stage. Images of the head of the guinea pig and the tibia knee joint of the rat were taken. In addition, an image of the rat's tail was taken. The reconstruction and the image viewing were carried out using I-View software. The voxel matrix was 512 x 512 x 384. The voxel sizes ranged from 10 x 10 x 10 μm to 100 x 100 x 100 μm. The exposure time was 17 s, and the reconstruction time was 150 s. The head of the guinea pig and the tibia/knee joint of the rat were observed clearly under 100-μm and 30μm voxels, respectively. The trabecular bone of the tail was also observed clearly under a 10 μm voxel. The newly developed micro-computed tomography system makes it possible to obtain images of anesthetized animals set on a secure object stage. Clear bone images of the small animals could be obtained within a short time. (author)

First results of micro-neutron tomography by use of a focussing neutron lens

CERN Document Server

Masschaele, B; Cauwels, P; Dierick, M; Jolie, J; Mondelaers, W

2001-01-01

Since the appearance of high flux neutron beams, scientists experimented with neutron radiography. This high beam flux combined with modern neutron to visible light converters leads to the possibility of performing fast neutron micro-tomography. The first results of cold neutron tomography with a neutron lens are presented in this article. Samples are rotated in the beam and the projections are recorded with a neutron camera. The 3D reconstruction is performed with cone beam reconstruction software.

Development of sealed sample containers and high resolution micro-tomography

Energy Technology Data Exchange (ETDEWEB)

Uesugi, Kentaro, E-mail: ueken@spring8.or.jp; Takeuchi, Akihisa; Suzuki, Yoshio [Japan synchrotron radiation research institute, JASRI/SPring-8 Kouto 1-1-1, Sayo, Hyogo 679-5198 Japan (Japan); Uesugi, Masayuki [Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Hamada, Hiroshi [NTT Advanced technology Corporation, Atsugi, Kanagawa 243-0124 (Japan)

2016-01-28

A sample container and a high resolution micro-tomography system have been developed at BL47XU at SPring-8. The container is made of a SiN membrane in a shape of truncated pyramid, which makes it possible to exclude oxygen and moisture in the air. The sample rotation stage for tomography is set downward to keep the sample in the container without any glue. The spatial resolution and field of view are 300 nm and 110 μm using a Fresnel zone plate objective with an outermost zone width of 100 nm at 8 keV, respectively. The scan time is about 20 minutes for 1800 projections. A 3-D image of an asteroid particle was successfully obtained without adhesive and contamination.

Micro-computed tomography of pupal metamorphosis in the solitary bee Megachile rotundata

Science.gov (United States)

Insect metamorphosis involves a complex change in form and function, but most of these changes are internal and treated as a black box. In this study, we examined development of the solitary bee, Megachile rotundata, using micro-computed tomography (µCT) and digital volume analysis. We describe deve...

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

International Nuclear Information System (INIS)

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

2012-01-01

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.

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

Science.gov (United States)

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.

Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography

Science.gov (United States)

Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

2015-01-01

Background Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Material/Methods Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. Results ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (protary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal. PMID:26092929

Conventional and 360 degree electron tomography of a micro-crystalline silicon solar cell

DEFF Research Database (Denmark)

Duchamp, Martial; Ramar, Amuthan; Kovács, András

2011-01-01

Bright-field (BF) and annular dark-field (ADF) electron tomography in the transmission electron microscope (TEM) are used to characterize elongated porous regions or cracks (simply referred to as cracks thereafter) in micro-crystalline silicon (μc-Si:H) solar cell. The limitations of inferring...

Three dimensional subsurface elemental identification of minerals using confocal micro-X-ray fluorescence and micro-X-ray computed tomography

International Nuclear Information System (INIS)

Cordes, Nikolaus L.; Seshadri, Srivatsan; Havrilla, George J.; Yuan, Xiaoli; Feser, Michael; Patterson, Brian M.

2015-01-01

Current non-destructive elemental characterization methods, such as scanning electron microscopy-based energy dispersive spectroscopy (SEM–EDS) and micro-X-ray fluorescence spectroscopy (MXRF), are limited to either elemental identification at the surface (SEM–EDS) or suffer from an inability to discriminate between surface or depth information (MXRF). Thus, a non-destructive elemental characterization of individual embedded particles beneath the surface is impossible with either of these techniques. This limitation can be overcome by using laboratory-based 3D confocal micro-X-ray fluorescence spectroscopy (confocal MXRF). This technique utilizes focusing optics on the X-ray source and detector which allows for spatial discrimination in all three dimensions. However, the voxel-by-voxel serial acquisition of a 3D elemental scan can be very time-intensive (~ 1 to 4 weeks) if it is necessary to locate individual embedded particles of interest. As an example, if each point takes a 5 s measurement time, a small volume of 50 × 50 × 50 pixels leads to an acquisition time of approximately 174 h, not including sample stage movement time. Initially screening the samples for particles of interest using micro-X-ray computed tomography (micro-CT) can significantly reduce the time required to spatially locate these particles. Once located, these individual particles can be elementally characterized with confocal MXRF. Herein, we report the elemental identification of high atomic number surface and subsurface particles embedded in a mineralogical matrix by coupling micro-CT and confocal MXRF. Synergistically, these two X-ray based techniques first rapidly locate and then elementally identify individual subsurface particles. - Highlights: • Coupling of confocal X-ray fluorescence spectroscopy and X-ray computed tomography • Qualitative elemental identification of surface and subsurface mineral particles • Non-destructive particle size measurements • Utilization of

Three dimensional subsurface elemental identification of minerals using confocal micro-X-ray fluorescence and micro-X-ray computed tomography

Energy Technology Data Exchange (ETDEWEB)

Cordes, Nikolaus L., E-mail: ncordes@lanl.gov [Polymers and Coatings Group, Material Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Seshadri, Srivatsan, E-mail: srivatsan.seshadri@zeiss.com [Carl Zeiss X-ray Microscopy, Inc., Pleasanton, CA 94588 (United States); Havrilla, George J. [Chemical Diagnostics and Engineering, Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Yuan, Xiaoli [Julius Kruttschnitt Mineral Research Centre, University of Queensland, Indooroopilly, Brisbane, QLD 4068 (Australia); Feser, Michael [Carl Zeiss X-ray Microscopy, Inc., Pleasanton, CA 94588 (United States); Patterson, Brian M. [Polymers and Coatings Group, Material Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2015-01-01

Current non-destructive elemental characterization methods, such as scanning electron microscopy-based energy dispersive spectroscopy (SEM–EDS) and micro-X-ray fluorescence spectroscopy (MXRF), are limited to either elemental identification at the surface (SEM–EDS) or suffer from an inability to discriminate between surface or depth information (MXRF). Thus, a non-destructive elemental characterization of individual embedded particles beneath the surface is impossible with either of these techniques. This limitation can be overcome by using laboratory-based 3D confocal micro-X-ray fluorescence spectroscopy (confocal MXRF). This technique utilizes focusing optics on the X-ray source and detector which allows for spatial discrimination in all three dimensions. However, the voxel-by-voxel serial acquisition of a 3D elemental scan can be very time-intensive (~ 1 to 4 weeks) if it is necessary to locate individual embedded particles of interest. As an example, if each point takes a 5 s measurement time, a small volume of 50 × 50 × 50 pixels leads to an acquisition time of approximately 174 h, not including sample stage movement time. Initially screening the samples for particles of interest using micro-X-ray computed tomography (micro-CT) can significantly reduce the time required to spatially locate these particles. Once located, these individual particles can be elementally characterized with confocal MXRF. Herein, we report the elemental identification of high atomic number surface and subsurface particles embedded in a mineralogical matrix by coupling micro-CT and confocal MXRF. Synergistically, these two X-ray based techniques first rapidly locate and then elementally identify individual subsurface particles. - Highlights: • Coupling of confocal X-ray fluorescence spectroscopy and X-ray computed tomography • Qualitative elemental identification of surface and subsurface mineral particles • Non-destructive particle size measurements • Utilization of

Novel Application of Micro-Computerized Tomography for Morphologic Characterization of the Murine Penis.

Science.gov (United States)

O'Neill, Marisol; Huang, Gene O; Lamb, Dolores J

2017-12-01

The murine penis model has enriched our understanding of anomalous penile development. The morphologic characterization of the murine penis using conventional serial sectioning methods is labor intensive and prone to errors. To develop a novel application of micro-computerized tomography (micro-CT) with iodine staining for rapid, non-destructive morphologic study of murine penis structure. Penises were dissected from 10 adult wild-type mice and imaged using micro-CT with iodine staining. Images were acquired at 5-μm spatial resolution on a Bruker SkyScan 1272 micro-CT system. After images were acquired, the specimens were washed of any remaining iodine and embedded in paraffin for conventional histologic examination. Histologic and micro-CT measurements for all specimens were made by 2 independent observers. Measurements of penile structures were made on virtual micro-CT sections and histologic slides. The Lin concordance correlation coefficient demonstrated almost perfect strength of agreement for interobserver variability for histologic section (0.9995, 95% CI = 0.9990-0.9997) and micro-CT section (0.9982, 95% CI = 0.9963-0.9991) measurements. Bland-Altman analysis for agreement between the 2 modalities of measurement demonstrated mean differences of -0.029, 0.022, and -0.068 mm for male urogenital mating protuberance, baculum, and penile glans length, respectively. There did not appear to be a bias for overestimation or underestimation of measured lengths and limits of agreement were narrow. The enhanced ability offered by micro-CT to phenotype the murine penis has the potential to improve translational studies examining the molecular pathways contributing to anomalous penile development. The present study describes the first reported use of micro-CT with iodine staining for imaging the murine penis. Producing repeated histologic sections of identical orientation was limited by inherent imperfections in mounting and tissue sectioning, but this was

Micro/nano-computed tomography technology for quantitative dynamic, multi-scale imaging of morphogenesis.

Science.gov (United States)

Gregg, Chelsea L; Recknagel, Andrew K; Butcher, Jonathan T

2015-01-01

Tissue morphogenesis and embryonic development are dynamic events challenging to quantify, especially considering the intricate events that happen simultaneously in different locations and time. Micro- and more recently nano-computed tomography (micro/nanoCT) has been used for the past 15 years to characterize large 3D fields of tortuous geometries at high spatial resolution. We and others have advanced micro/nanoCT imaging strategies for quantifying tissue- and organ-level fate changes throughout morphogenesis. Exogenous soft tissue contrast media enables visualization of vascular lumens and tissues via extravasation. Furthermore, the emergence of antigen-specific tissue contrast enables direct quantitative visualization of protein and mRNA expression. Micro-CT X-ray doses appear to be non-embryotoxic, enabling longitudinal imaging studies in live embryos. In this chapter we present established soft tissue contrast protocols for obtaining high-quality micro/nanoCT images and the image processing techniques useful for quantifying anatomical and physiological information from the data sets.

Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography.

Science.gov (United States)

Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

2015-06-20

Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (p<0.001). Similarly, there was a statistically significant difference in root canal straightening after preparation between the techniques (p<0.001). Neither manual nor rotary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal.

Dental imaging using laminar optical tomography and micro CT

Science.gov (United States)

Long, Feixiao; Ozturk, Mehmet S.; Intes, Xavier; Kotha, Shiva

2014-02-01

Dental lesions located in the pulp are quite difficult to identify based on anatomical contrast, and, hence, to diagnose using traditional imaging methods such as dental CT. However, such lesions could lead to functional and/or molecular optical contrast. Herein, we report on the preliminary investigation of using Laminar Optical Tomography (LOT) to image the pulp and root canals in teeth. LOT is a non-contact, high resolution, molecular and functional mesoscopic optical imaging modality. To investigate the potential of LOT for dental imaging, we injected an optical dye into ex vivo teeth samples and imaged them using LOT and micro-CT simultaneously. A rigid image registration between the LOT and micro-CT reconstruction was obtained, validating the potential of LOT to image molecular optical contrast deep in the teeth with accuracy, non-invasively. We demonstrate that LOT can retrieve the 3D bio-distribution of molecular probes at depths up to 2mm with a resolution of several hundred microns in teeth.

68Ga-labeling and in vivo evaluation of a uPAR binding DOTA- and NODAGA-conjugated peptide for PET imaging of invasive cancers

DEFF Research Database (Denmark)

Persson, Morten; Madsen, Jacob; Østergaard, Søren

2012-01-01

, uPAR binding affinity and cell uptake were determined. To characterize the in vivo properties, dynamic microPET imaging was carried out in nude mice bearing human glioma U87MG tumor xenograft. RESULTS: In vitro experiments revealed uPAR binding affinities in the lower nM range for both conjugated......-AE105-NH(2) was observed. Good stability in phosphate-buffered saline and mouse plasma was observed. High cell uptake was found for both tracers in U87MG tumor cells. Dynamic microPET imaging demonstrated good tumor-to-background ratio for both tracers. Tumor uptake was 2.1% ID/g and 1.3% ID/g 30 min...... positron emission tomography (PET) in human cancer xenograft mice models. Here we introduce (68)Ga-DOTA-AE105-NH(2) and (68)Ga-NODAGA-AE105-NH(2) and evaluate their imaging properties using small-animal PET. METHODS: Synthesis of DOTA-AE105-NH(2) and NODAGA-AE105-NH(2) was based on solid-phase peptide...

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

Science.gov (United States)

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 micro-CT showed the highest correlation coefficient with BIC from histologic slides when the PSD was 5 to 7 (P micro-CT showed a very high correlation with BV/TV from histologic slides in all ranges (P micro-CT, at least 5 PSD from the metal implant surface is needed.

Preliminary results for X-ray phase contrast micro-tomography on the biomedical imaging beamline at SSRF

International Nuclear Information System (INIS)

Chen Rongchang; Du Guohao; Xie Honglan; Deng Biao; Tong Yajun; Hu Wen; Xue Yanling; Chen Can; Ren Yuqi; Zhou Guangzhao; Wang Yudan; Xiao Tiqiao; Xu Hongjie; Zhu Peiping

2009-01-01

With X-ray phase contrast micro-tomography(CT), one is able to obtain edge-enhanced image of internal structure of the samples. This allows visualization of the fine internal features for biology tissues, which is not able to resolve by conventional absorption CT. After preliminary modulation, monochromatic X-rays (8-72.5 keV) are available for experiments on the experimental station of the biomedical imaging beamline at Shanghai Synchrotron Radiation Facility(SSRF). In this paper, we report the in line phase contrast micro-tomography(IL-XPCT) of biology sample (locust) on the beamline. The reconstruct slice images and three dimensional rendering images of the locust were obtained, with clearly visible images of locus's wing, surface texture and internal tissue distribution. (authors)

Spectroscopic micro-tomography of metallic-organic composites by means of photon-counting detectors

Czech Academy of Sciences Publication Activity Database

Pichotka, Martin; Jakůbek, Jan; Vavřík, Daniel

2015-01-01

Roč. 10, č. 12 (2015), C12033 ISSN 1748-0221 R&D Projects: GA MŠk(CZ) LO1219 Keywords : micro-tomography * photon-counting detectors * metallic-organic composites Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.310, year: 2015 http://iopscience.iop.org/article/10.1088/1748-0221/10/12/C12033/pdf

CHARACTERISTICS OF EPIRETINAL MEMBRANE REMNANT EDGE BY OPTICAL COHERENCE TOMOGRAPHY AFTER PARS PLANA VITRECTOMY.

Science.gov (United States)

Gaber, Raouf; You, Qi Sheng; Muftuoglu, Ilkay Kilic; Alam, Mostafa; Tsai, Frank F; Mendoza, Nadia; Freeman, William R

2017-11-01

To evaluate the incidence, characteristics, and the progression of epiretinal membrane (ERM) remnant edge seen by optical coherence tomography after ERM peeling. A retrospective chart review was conducted for 86 eyes of 85 consecutive patients who were diagnosed with ERM and underwent pars plana vitrectomy for epiretinal membrane peeling between 2013 and 2014. Data collected and analyzed included age, gender, preoperative and postoperative visual acuity, use of indocyanine green dye to stain internal limiting membrane, tamponade used after vitrectomy, ERM edge boundaries, presence of cystoid macular edema, and central foveal thickness. An ERM remnant edge was detected in 33/86 study eyes (38.4%) at the first postoperative optical coherence tomography scan. Compared with those without an ERM remnant, patients with an ERM remnant after surgery were significantly older at baseline and had a higher incidence of ERM recurrence at their last visit. They were not significantly different in terms of gender, preoperative and postoperative visual acuity, reduction of central foveal thickness from baseline, proportion of eyes with preoperative ERM elevation on optical coherence tomography, presence of macular edema before surgery, intraoperative use of indocyanine green staining for ILM peeling, or tamponade used. Based on the edge morphology, we classified the ERM remnant into three types: Type 1 was flat and blended with the retina (14/33 eyes, 42.4%), Type 2 was flat but stepped (17/33 eyes, 51.5%), and Type 3 was elevated (2/33 eyes, 6.0%). A significantly higher risk of ERM recurrence was seen in Type 2 and Type 3 ERM remnants (75% and 100%, respectively) than Type 1 ERM remnants (10%). An ERM remnant edge was detected by optical coherence tomography after ERM peeling in 38.4% of eyes. The presence of a postoperative ERM edge was associated with a higher risk of ERM recurrence, particularly in Type 2 and Type 3 ERM remnants.

Complex Odontoma: A Case Report with Micro-Computed Tomography Findings

Directory of Open Access Journals (Sweden)

L. A. N. Santos

2016-01-01

Full Text Available Odontomas are the most common benign tumors of odontogenic origin. They are normally diagnosed on routine radiographs, due to the absence of symptoms. Histopathologic evaluation confirms the diagnosis especially in cases of complex odontoma, which may be confused during radiographic examination with an osteoma or other highly calcified bone lesions. The micro-CT is a new technology that enables three-dimensional analysis with better spatial resolution compared with cone beam computed tomography. Another great advantage of this technology is that the sample does not need special preparation or destruction in the sectioned area as in histopathologic evaluation. An odontoma with CBCT and microtomography images is presented in a 26-year-old man. It was first observed on panoramic radiographs and then by CBCT. The lesion and the impacted third molar were surgically excised using a modified Neumann approach. After removal, it was evaluated by histopathology and microtomography to confirm the diagnostic hypothesis. According to the results, micro-CT enabled the assessment of the sample similar to histopathology, without destruction of the sample. With further development, micro-CT could be a powerful diagnostic tool in future research.

Micro computed tomography features of laryngeal fractures in a case of fatal manual strangulation.

Science.gov (United States)

Fais, Paolo; Giraudo, Chiara; Viero, Alessia; Miotto, Diego; Bortolotti, Federica; Tagliaro, Franco; Montisci, Massimo; Cecchetto, Giovanni

2016-01-01

Cases of subtle fatal neck compression are often complicated by the lack of specificity of the post-mortem signs of asphyxia and by the lack of clear signs of neck compression. Herein we present a forensic case of a 45-year-old schizophrenic patient found on the floor of the bedroom of a psychiatric ward in cardiopulmonary arrest and who died after two days in a vegetative state. The deposition of the roommate of the deceased, who claimed responsibility for the killing of the victim by neck compression, was considered unreliable by the prosecutor. Autopsy, toxicological analyses, and multi-slice computed tomography (MSCT), micro computed tomography (micro-CT) and histology of the larynx complex were performed. Particularly, micro-CT analysis of the thyroid cartilage revealed the bilateral presence of ossified triticeous cartilages and the complete fragmentation of the right superior horn of the thyroid, but it additionally demonstrated a fracture on the contralateral superior horns, which was not clearly diagnosable at MSCT. On the basis of the evidence of intracartilaginous laryngeal hemorrhages and bilateral microfracture at the base of the superior horns of the larynx, the death was classified as a case of asphyxia due to manual strangulation. Micro-CT was confirmed as a useful tool in cases of subtle fatal neck compression, for the detection of minute laryngeal cartilage fractures, especially in complex cases with equivocal findings on MSCT. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Validation of Optical Coherence Tomography against Micro-computed Tomography for Evaluation of Remaining Coronal Dentin Thickness.

Science.gov (United States)

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 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.

Application of micro-computed tomography to microstructure studies of the medicinal fungus Hericium coralloides.

Science.gov (United States)

Pallua, Johannes D; Kuhn, Volker; Pallua, Anton F; Pfaller, Kristian; Pallua, Anton K; Recheis, Wolfgang; Pöder, Reinhold

2015-01-01

The potential of 3-D nondestructive imaging techniques such as micro-computed tomography (micro-CT) was evaluated to study morphological patterns of the potential medicinal fungus Hericium coralloides (Basidiomycota). Micro-CT results were correlated with histological information gained from scanning electron microscopy (SEM) and light microscopy (LM). It is demonstrated that the combination of these imaging methods results in a more distinct picture of the morphology of the edible and potentially medicinal Hericium coralloides basidiomata. In addition we have created 3-D reconstructions and visualizations based on micro-CT imagery from a randomly selected part of the upper region of a fresh H. coralloides basidioma: Analyses for the first time allowed an approximation of the evolutionary effectiveness of this bizarrely formed basidioma type in terms of the investment of tissue biomass and its reproductive output (production of basidiospores). © 2015 by The Mycological Society of America.

Inside marginal adaptation of crowns by X-ray micro-computed tomography

International Nuclear Information System (INIS)

Dos Santos, T. M.; Lima, I.; Lopes, R. T.; Author, S. B. Jr.

2015-01-01

The objective of this work was to access dental arcade by using X-ray micro-computed tomography. For this purpose high resolution system was used and three groups were studied: Zirkonzahn CAD-CAM system, IPS e.max Press, and metal ceramic. The three systems assessed in this study showed results of marginal and discrepancy gaps clinically accepted. The great result of 2D and 3D evaluations showed that the used technique is a powerful method to investigate quantitative characteristics of dental arcade. (authors)

Inside marginal adaptation of crowns by X-ray micro-computed tomography

Energy Technology Data Exchange (ETDEWEB)

Dos Santos, T. M.; Lima, I.; Lopes, R. T. [Nuclear Instrumentation Laboratory, Nuclear Engineering Program, Federal University of Rio de Janeiro, RJ, (Brazil); Author, S. B. Jr. [Department of Physics, Colorado State University, Ft. Collins, CO 80523, (United States)

2015-07-01

The objective of this work was to access dental arcade by using X-ray micro-computed tomography. For this purpose high resolution system was used and three groups were studied: Zirkonzahn CAD-CAM system, IPS e.max Press, and metal ceramic. The three systems assessed in this study showed results of marginal and discrepancy gaps clinically accepted. The great result of 2D and 3D evaluations showed that the used technique is a powerful method to investigate quantitative characteristics of dental arcade. (authors)

Non-destructive analysis of micro texture and grain boundary character from X-ray diffraction contrast tomography

DEFF Research Database (Denmark)

King, A.; Herbig, M.; Ludwig, W.

2010-01-01

Recent advances in synchrotron based X-ray imaging and diffraction techniques offer interesting new possibilities for mapping 3D grain shapes and crystallographic orientations in different classes of polycrystalline materials. X-ray diffraction contrast tomography (DCT) is a monochromatic beam...... imaging technique combining the principles of X-ray micro-tomography and three-dimensional X-ray diffraction microscopy (3DXRD). DCT provides simultaneous access to 3D grain shape, crystallographic orientation and attenuation coefficient distribution at the micrometer length scale. The microtexture...

Development of a 3-D x-ray micro-tomography system and its application to trabecular bone/cement interface

International Nuclear Information System (INIS)

Chi, Yong Ki; Cho, Gyuseong

2004-01-01

In recent years, the interface analysis of micro-structure based objects is an important research in osteoporosis, vascular imaging since a 3-D X-ray micro-tomography system was developed. However, the micro-tomographic image shows the white-out appearance in case of imaging of similar density objects with low energy X-ray. Therefore these images must be analyzed about the interface between microstructure based objects for its application to biomechanical study. Many published studies suggested approximately assumed model of interface and predicted mechanical failure by means of Finite Element Method (FEM) but these FEM analysis has not used for modeling the real structure and interface between objects such as roughness, voids and pores of objects. We developed micro-tomography system and suggest the application of micro-tomographic image for predicting mechanical failure at the interface. The micro-tomography system consists of a 5 μm micro-focus X-ray tube, a CMOS-based image sensor and a rotating sample holder controlled by a precision motor. CMOS image sensor has 62x62 mm 2 sensing area and uses optical lenses system for increasing resolution. The sample which was manufactured by implanting cement in a pig hip bone was used and its fracture is considered to be an important cause of loosening of hip joint replacement in orthopedic implants. A Feldkamp's cone-beam reconstruction algorithm on the equispatial detector case was used for bone/cement 3D volume data and the analysis of a trabecular bone/cement interface containing white-out appearance was performed by using multiple criterion segmentation of region and volume. Finally, the segmented data can be used for fracture prediction of FEM by determining node of hexahedron meshing. In this paper, we present development of a 3-D cone beam micro-tomographic system with CMOS image sensor and its application to a complex structure of a trabecular bone and implanted cement for predicting the failure mechanism of

Quantification of lung fibrosis and emphysema in mice using automated micro-computed tomography.

Directory of Open Access Journals (Sweden)

Ellen De Langhe

Full Text Available BACKGROUND: In vivo high-resolution micro-computed tomography allows for longitudinal image-based measurements in animal models of lung disease. The combination of repetitive high resolution imaging with fully automated quantitative image analysis in mouse models of lung fibrosis lung benefits preclinical research. This study aimed to develop and validate such an automated micro-computed tomography analysis algorithm for quantification of aerated lung volume in mice; an indicator of pulmonary fibrosis and emphysema severity. METHODOLOGY: Mice received an intratracheal instillation of bleomycin (n = 8, elastase (0.25 U elastase n = 9, 0.5 U elastase n = 8 or saline control (n = 6 for fibrosis, n = 5 for emphysema. A subset of mice was scanned without intervention, to evaluate potential radiation-induced toxicity (n = 4. Some bleomycin-instilled mice were treated with imatinib for proof of concept (n = 8. Mice were scanned weekly, until four weeks after induction, when they underwent pulmonary function testing, lung histology and collagen quantification. Aerated lung volumes were calculated with our automated algorithm. PRINCIPAL FINDINGS: Our automated image-based aerated lung volume quantification method is reproducible with low intra-subject variability. Bleomycin-treated mice had significantly lower scan-derived aerated lung volumes, compared to controls. Aerated lung volume correlated with the histopathological fibrosis score and total lung collagen content. Inversely, a dose-dependent increase in lung volume was observed in elastase-treated mice. Serial scanning of individual mice is feasible and visualized dynamic disease progression. No radiation-induced toxicity was observed. Three-dimensional images provided critical topographical information. CONCLUSIONS: We report on a high resolution in vivo micro-computed tomography image analysis algorithm that runs fully automated and allows quantification of aerated lung volume in mice. This

The dynamic micro computed tomography at SSRF

Science.gov (United States)

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.

X-ray micro-modulated luminescence tomography (XMLT)

Science.gov (United States)

Cong, Wenxiang; Liu, Fenglin; Wang, Chao; Wang, Ge

2014-01-01

Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to strong scattering of light in a biological sample. X-ray microscopy can resolve spatial details of few microns deep inside a sample but contrast resolution is inadequate to depict heterogeneous features at cellular or sub-cellular levels. To enhance and enrich biological contrast at large imaging depth, various nanoparticles are introduced and become essential to basic research and molecular medicine. Nanoparticles can be functionalized as imaging probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+ nanoparticles were recently synthesized to facilitate luminescence energy storage with x-ray pre-excitation and subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we propose an x-ray micro-modulated luminescence tomography (XMLT, or MLT to be more general) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonstrate the feasibility of the proposed approach. PMID:24663898

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

Science.gov (United States)

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 (pimplants using micro-CT analysis using a region-based segmentation method.

X-ray micro-tomography for investigations of brain tissues on cellular level

Science.gov (United States)

Khimchenko, Anna; Schulz, Georg; Deyhle, Hans; Thalmann, Peter; Zanette, Irene; Zdora, Marie-Christine; Bikis, Christos; Hipp, Alexander; Hieber, Simone E.; Schweighauser, Gabriel; Hench, Jürgen; Müller, Bert

2016-10-01

X-ray imaging in absorption contrast mode is well established for hard tissue visualization. However, performance for lower density materials is limited due to a reduced contrast. Our aim is three-dimensional (3D) characterization of micro-morphology of human brain tissues down to (sub-)cellular resolution within a laboratory environment. Using the laboratory-based microtomography (μCT) system nanotom m (GE Sensing and Inspection Technologies GmbH, Wunstorf, Germany) and synchrotron radiation at the Diamond-Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK), we have acquired 3D data with a resolution down to 0.45 μm for visualization of a human cerebellum specimen down to cellular level. We have shown that all selected modalities, namely laboratory-based absorption contrast micro-tomography (LBμCT), synchrotron radiation based in-line single distance phase contrast tomography (SDPR) and synchrotron radiation based single-grating interferometry (GI), can reach cellular resolution for tissue samples with a size in the mm-range. The results are discussed qualitatively in comparison to optical microscopy of haematoxylin and eosin (HE) stained sections. As phase contrast yields to a better data quality for soft tissues and in order to overcome restrictions of limited beamline access for phase contrast measurements, we have equipped the μCT system nanotom m with a double-grating phase contrast set-up. Preliminary experimental results of a knee sample consisting of a bony part and a cartilage demonstrate that phase contrast data exhibits better quality compared to absorption contrast. Currently, the set-up is under adjustment. It is expected that cellular resolution would also be achieved. The questions arise (1) what would be the quality gain of laboratory-based phase contrast in comparison to laboratory-based absorption contrast tomography and (2) could laboratory-based phase contrast data provide comparable results to synchrotron radiation based

First (18)F-labeled ligand for PET imaging of uPAR

DEFF Research Database (Denmark)

Persson, Morten; Liu, Hongguang; Madsen, Jacob

2013-01-01

Urokinase-type plasminogen activator receptor (uPAR) is overexpressed in human prostate cancer and uPAR has been found to be associated with metastatic disease and poor prognosis. AE105 is a small linear peptide with high binding affinity to uPAR. We synthesized an N-terminal NOTA......-conjugated version (NOTA-AE105) for development of the first (18)F-labeled uPAR positron-emission-tomography PET ligand using the Al(18)F radiolabeling method. In this study, the potential of (18)F-AlF-NOTA-AE105 to specifically target uPAR-positive prostate tumors was investigated....

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

Energy Technology Data Exchange (ETDEWEB)

Mitroglou, N.; Lorenzi, M.; Gavaises, M. [City University London, School of Mathematics Computer Science and Engineering, London (United Kingdom); Santini, M. [University of Bergamo, Department of Engineering, Bergamo (Italy)

2016-11-15

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. (orig.)

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

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

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

2016-01-01

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. (orig.)

Diagnostic accuracy of 3-T magnetic resonance imaging with 3D T1 VIBE versus computer tomography in pars stress fracture of the lumbar spine

Energy Technology Data Exchange (ETDEWEB)

Ang, E.C.; Robertson, A.F.; Malara, F.A.; O' Shea, T.; Roebert, J.K.; Rotstein, A.H. [Victoria House Medical Imaging, Prahran, Victoria (Australia); Schneider, M.E. [Monash University, Monash Biomedicine Discovery Institute, Department of Medical Imaging and Radiation Sciences, Faculty of Medicine, Nursing and Health Sciences, Clayton, Victoria (Australia)

2016-11-15

To compare the diagnostic accuracy of 3-T magnetic resonance imaging (MRI) with thin-slice 3D T1 VIBE sequence to 128-slice computer tomography (CT) in pars stress fractures of the lumbar spine. 3-T MRI and CT of 24 patients involving 70 pars interarticularis were retrospectively reviewed by four blinded radiologists. The fracture morphology (complete, incomplete, or normal) was assessed on MRI and CT at different time points. Pars interarticularis bone marrow edema (present or absent) was also evaluated on MRI. In total, 14 complete fractures, 31 incomplete fractures and 25 normal pars were detected by CT. Bone marrow edema was seen in seven of the complete and 25 of the incomplete fractures. The overall sensitivity, specificity and accuracy of MRI in detecting fractures (complete and incomplete) were 97.7, 92.3, and 95.7 %, respectively. MRI was 100 % accurate in detecting complete fractures. For incomplete fractures, the sensitivity, specificity, and accuracy of MRI were 96.7, 92.0, and 94.6 %, respectively. 3-T MRI with thin-slice 3D T1 VIBE is 100 % accurate in diagnosing complete pars fractures and has excellent diagnostic ability in the detection and characterization of incomplete pars stress fractures compared to CT. MRI has the added advantages of detecting bone marrow edema and does not employ ionizing radiation. (orig.)

Diagnostic accuracy of 3-T magnetic resonance imaging with 3D T1 VIBE versus computer tomography in pars stress fracture of the lumbar spine

International Nuclear Information System (INIS)

Ang, E.C.; Robertson, A.F.; Malara, F.A.; O'Shea, T.; Roebert, J.K.; Rotstein, A.H.; Schneider, M.E.

2016-01-01

To compare the diagnostic accuracy of 3-T magnetic resonance imaging (MRI) with thin-slice 3D T1 VIBE sequence to 128-slice computer tomography (CT) in pars stress fractures of the lumbar spine. 3-T MRI and CT of 24 patients involving 70 pars interarticularis were retrospectively reviewed by four blinded radiologists. The fracture morphology (complete, incomplete, or normal) was assessed on MRI and CT at different time points. Pars interarticularis bone marrow edema (present or absent) was also evaluated on MRI. In total, 14 complete fractures, 31 incomplete fractures and 25 normal pars were detected by CT. Bone marrow edema was seen in seven of the complete and 25 of the incomplete fractures. The overall sensitivity, specificity and accuracy of MRI in detecting fractures (complete and incomplete) were 97.7, 92.3, and 95.7 %, respectively. MRI was 100 % accurate in detecting complete fractures. For incomplete fractures, the sensitivity, specificity, and accuracy of MRI were 96.7, 92.0, and 94.6 %, respectively. 3-T MRI with thin-slice 3D T1 VIBE is 100 % accurate in diagnosing complete pars fractures and has excellent diagnostic ability in the detection and characterization of incomplete pars stress fractures compared to CT. MRI has the added advantages of detecting bone marrow edema and does not employ ionizing radiation. (orig.)

Production des micro-algues des claires ostréicoles en relation avec l'azote organique dissous excrété par les huîtres

OpenAIRE

Robert, Jean-michel; Maestrini, Serge; Heral, Maurice; Zanette, Yvan

1981-01-01

L'utilisation de tests biologiques dans l'étude de la fertilité des eaux de claires ainsi que l'analyse chimique des réserves en sels nutritifs des mêmes eaux montrent qu'une part importante de la biomasse micro-algale peut être produite dans ces bassins, par assimilation par les cellules de substances organiques dissoutes. Ainsi, pour l'azote, des estimations indirectes aboutissent à des quantités de cet élément assimilé sous forme organique variant entre 0,6 et 30,7 µg-at.I-1 selon les mode...

Physical properties of root cementum: Part 26. Effects of micro-osteoperforations on orthodontic root resorption: A microcomputed tomography study.

Science.gov (United States)

Chan, Emmanuel; Dalci, Oyku; Petocz, Peter; Papadopoulou, Alexandra K; Darendeliler, M Ali

2018-02-01

Studies have demonstrated the potential efficacy of micro-osteoperforations in accelerating tooth movement by amplifying the expression of inflammatory markers. The aim of this investigation was to examine the effects of micro-osteoperforations on orthodontic root resorption with microcomputed tomography. This prospective controlled clinical trial involved 20 subjects requiring extraction of the maxillary first premolars as part of their orthodontic treatment. A buccal tipping force of 150 g was applied to both premolars. Using the Propel appliance (Propel Orthodontics, San Jose, Calif), micro-osteoperforations were applied at a depth of 5 mm on the mesial and distal aspects in the midroot region of the experimental side of the first premolar root; the contralateral side served as the control. After 28 days, both premolars were extracted. The teeth were scanned under microcomputed tomography, and the volumes of root resorption craters were calculated and compared. Premolars treated with micro-osteoperforation exhibited significantly greater average total amounts of root resorption than did the control teeth (0.576 vs 0.406 mm 3 ). The total average volumetric root loss of premolars treated with micro-osteoperforation was 42% greater than that of the control teeth. This 28-day trial showed that micro-osteoperforations resulted in greater orthodontic root resorption. However, these results should be verified in patients who are undergoing full-length orthodontic treatment. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Mechanical behaviour and rupture in clayey rocks studied by x-ray micro tomography

International Nuclear Information System (INIS)

Lenoir, N.

2006-03-01

Within the framework of feasibility studies of underground repositories for radioactive waste, the study of permeability evolution with damage of the host layer is crucial. The goals of this work were: (i) to characterize experimentally the damage of two clayey rocks (BEAUCAIRE MARL and EAST SHALE) with x-ray micro tomography, (ii) to develop a high pressure triaxial set-up adapted to permeability measurement on very low permeability rocks.A number of original triaxial devices have been realised to characterize damage of clayey rocks, under deviatoric loading, with x-ray micro tomography on a synchrotron beamline at the ESRF (Grenoble). Localized damage and its evolution have been characterized at a fine scale (of order of ten microns). Digital image correlation techniques, extended to 3d images, have been used to measure incremental strain fields from tomographic images. we demonstrated that these techniques are very useful in the study of the localized damage of geo-materials and especially for the initiation. A high pressure triaxial device has been realised to measure permeability evolution of the east shale as a function of applied stress (isotropic and deviatoric). The particularity of this set-up is the small size of the test specimen (cylinder of 10 mm in diameter and 20 mm in height) which allows significant reduction of test duration. (author)

Early Lung Adenocarcinoma in Mice: Micro-Computed Tomography Manifestations and Correlation with Pathology

Directory of Open Access Journals (Sweden)

Lin Deng

2017-06-01

Full Text Available Lung cancer is the most common fatal malignancy for both men and women and adenocarcinoma is the most common histologic type. Early diagnosis of lung cancer can significantly improve the survival rate of patients. This study aimed to investigate the micro-computed tomography (micro-CT manifestations of early lung adenocarcinoma (LAC in mice and to provide a new perspective for early clinical diagnosis. Early LAC models in 10 mice were established by subcutaneously injecting 1-methyl-3-nitro-1-nitrosoguanidine (MNNG solution. Micro-CT scan and multiple planar reconstruction (MPR were used for mouse lungs. Micro-CT features of early LAC, especially the relationships between tumor and bronchus, were analyzed and correlated with pathology. Micro-CT findings of early LAC were divided into three types: non-solid (n = 8, 6%, partly solid (n = 85, 64% and totally solid (n = 39, 30%. Tumor-bronchus relationships, which could be observed in 110 of 132(83% LAC, were classified into four patterns: type I (n = 16, 15%, bronchus was truncated at the margin of the tumor; type II (n = 33, 30%, bronchus penetrated into the tumor with tapered narrowing and interruption; type III (n = 38, 35%, bronchus penetrated into the tumor with a patent and intact lumen; type IV (n = 99, 90%, bronchus ran at the border of the tumor with an intact or compressed lumen. Micro-CT manifestations of early LAC correlated well with pathological findings. Micro-CT can clearly demonstrate the features of mouse early LAC and bronchus-tumor relationships, and can also provide a new tool and perspective for the study of early LAC.

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

Energy Technology Data Exchange (ETDEWEB)

Kang, Sung Won; Lee, Woo Jin; Choi, Soon Chul; Lee, Sam Sun; Heo, Min Suk; Huh, Kyung Hoe; Kim, Tae Il; Yi, Won Ji [Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

2015-03-15

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.

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

International Nuclear Information System (INIS)

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

2015-01-01

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.

Technical aspects of X-ray micro-computed tomography. Initial experience of 27-μm resolution using feldkamp cone-beam reconstruction

International Nuclear Information System (INIS)

Yamamoto, Shuji; Suzuki, Masahiro; Kohara, Kazushi; Iinuma, Gen; Moriyama, Noriyuki

2007-01-01

The objective of this study was to introduce the technical utility of micro-computed tomography (CT) with 27-μm resolution by cone-beam CT algorithm. Whole-body micro-CT scans were performed to honeybee. Two- and three-dimensional image analyses were performed by originally developed and available open-source software for acquired images. The original contribution of this work is to describe the technical characteristics of the X-ray micro-CT system, keeping a small experimental insect in a unique condition. Micro-CT may be used as a rapid prototyping tool to research and understand the high-resolution system with Feldkamp cone-beam reconstruction. (author)

Imaging cellular and subcellular structure of human brain tissue using micro computed tomography

Science.gov (United States)

Khimchenko, Anna; Bikis, Christos; Schweighauser, Gabriel; Hench, Jürgen; Joita-Pacureanu, Alexandra-Teodora; Thalmann, Peter; Deyhle, Hans; Osmani, Bekim; Chicherova, Natalia; Hieber, Simone E.; Cloetens, Peter; Müller-Gerbl, Magdalena; Schulz, Georg; Müller, Bert

2017-09-01

Brain tissues have been an attractive subject for investigations in neuropathology, neuroscience, and neurobiol- ogy. Nevertheless, existing imaging methodologies have intrinsic limitations in three-dimensional (3D) label-free visualisation of extended tissue samples down to (sub)cellular level. For a long time, these morphological features were visualised by electron or light microscopies. In addition to being time-consuming, microscopic investigation includes specimen fixation, embedding, sectioning, staining, and imaging with the associated artefacts. More- over, optical microscopy remains hampered by a fundamental limit in the spatial resolution that is imposed by the diffraction of visible light wavefront. In contrast, various tomography approaches do not require a complex specimen preparation and can now reach a true (sub)cellular resolution. Even laboratory-based micro computed tomography in the absorption-contrast mode of formalin-fixed paraffin-embedded (FFPE) human cerebellum yields an image contrast comparable to conventional histological sections. Data of a superior image quality was obtained by means of synchrotron radiation-based single-distance X-ray phase-contrast tomography enabling the visualisation of non-stained Purkinje cells down to the subcellular level and automated cell counting. The question arises, whether the data quality of the hard X-ray tomography can be superior to optical microscopy. Herein, we discuss the label-free investigation of the human brain ultramorphology be means of synchrotron radiation-based hard X-ray magnified phase-contrast in-line tomography at the nano-imaging beamline ID16A (ESRF, Grenoble, France). As an example, we present images of FFPE human cerebellum block. Hard X-ray tomography can provide detailed information on human tissues in health and disease with a spatial resolution below the optical limit, improving understanding of the neuro-degenerative diseases.

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

Energy Technology Data Exchange (ETDEWEB)

Van Stappen, Jeroen, E-mail: Jeroen.Vanstappen@ugent.be [UGCT/PProGRess, Dept. of Geology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent (Belgium); SIM vzw, Technologiepark 935, B-9052 Zwijnaarde (Belgium); Bultreys, Tom [UGCT/PProGRess, Dept. of Geology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent (Belgium); Gilabert, Francisco A. [Mechanics of Materials and Structures, Dept. of Materials Science and Engineering, Ghent University, Technologiepark Zwijnaarde 903, B-9052 Zwijnaarde (Belgium); SIM vzw, Technologiepark 935, B-9052 Zwijnaarde (Belgium); Hillewaere, Xander K.D. [Polymer Chemistry Research Group, Dept. of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 S4-bis, B-9000 Ghent (Belgium); SIM vzw, Technologiepark 935, B-9052 Zwijnaarde (Belgium); Gómez, David Garoz [Mechanics of Materials and Structures, Dept. of Materials Science and Engineering, Ghent University, Technologiepark Zwijnaarde 903, B-9052 Zwijnaarde (Belgium); SIM vzw, Technologiepark 935, B-9052 Zwijnaarde (Belgium); Van Tittelboom, Kim [Magnel Laboratory for Concrete Research, Dept. of Structural Engineering, Ghent University, Technologiepark Zwijnaarde 904, B-9052 Ghent (Belgium); Dhaene, Jelle [UGCT/Radiation Physics, Dept. of Physics and Astronomy, Ghent University, Proeftuinstraat 86, B-9000 Ghent (Belgium); De Belie, Nele [Magnel Laboratory for Concrete Research, Dept. of Structural Engineering, Ghent University, Technologiepark Zwijnaarde 904, B-9052 Ghent (Belgium); Van Paepegem, Wim [Mechanics of Materials and Structures, Dept. of Materials Science and Engineering, Ghent University, Technologiepark Zwijnaarde 903, B-9052 Zwijnaarde (Belgium); Du Prez, Filip E. [Polymer Chemistry Research Group, Dept. of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 S4-bis, B-9000 Ghent (Belgium); Cnudde, Veerle [UGCT/PProGRess, Dept. of Geology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent (Belgium)

2016-09-15

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 behavior 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.

First-in-human uPAR PET: Imaging of Cancer Aggressiveness

Science.gov (United States)

Persson, Morten; Skovgaard, Dorthe; Brandt-Larsen, Malene; Christensen, Camilla; Madsen, Jacob; Nielsen, Carsten H.; Thurison, Tine; Klausen, Thomas Levin; Holm, Søren; Loft, Annika; Berthelsen, Anne Kiil; Ploug, Michael; Pappot, Helle; Brasso, Klaus; Kroman, Niels; Højgaard, Liselotte; Kjaer, Andreas

2015-01-01

A first-in-human clinical trial with Positron Emission Tomography (PET) imaging of the urokinase-type plasminogen activator receptor (uPAR) in patients with breast, prostate and bladder cancer, is described. uPAR is expressed in many types of human cancers and the expression is predictive of invasion, metastasis and indicates poor prognosis. uPAR PET imaging therefore holds promise to be a new and innovative method for improved cancer diagnosis, staging and individual risk stratification. The uPAR specific peptide AE105 was conjugated to the macrocyclic chelator DOTA and labeled with 64Cu for targeted molecular imaging with PET. The safety, pharmacokinetic, biodistribution profile and radiation dosimetry after a single intravenous dose of 64Cu-DOTA-AE105 were assessed by serial PET and computed tomography (CT) in 4 prostate, 3 breast and 3 bladder cancer patients. Safety assessment with laboratory blood screening tests was performed before and after PET ligand injection. In a subgroup of the patients, the in vivo stability of our targeted PET ligand was determined in collected blood and urine. No adverse or clinically detectable side effects in any of the 10 patients were found. The ligand exhibited good in vivo stability and fast clearance from plasma and tissue compartments by renal excretion. In addition, high uptake in both primary tumor lesions and lymph node metastases was seen and paralleled high uPAR expression in excised tumor tissue. Overall, this first-in-human study therefore provides promising evidence for safe use of 64Cu-DOTA-AE105 for uPAR PET imaging in cancer patients. PMID:26516369

New illuminations approaches with single-use micro LEDs endoilluminators for the pars plana vitrectomy

Science.gov (United States)

Koelbl, Philipp Simon; Koch, Frank H. J.; Lingenfelder, Christian; Hessling, Martin

2018-02-01

The illumination of the intraocular space during pars plana vitrectomy always bears the risk of retina damage by irradiation. Conventional illumination systems consist of an external light source and an optical fiber to transfer the visible light (radiation) into the eye. Often xenon arc and halogen lamps are employed for this application with some disadvantageous properties like high phototoxicity and low efficiency. Therefore, we propose to generate the light directly within the eye by inserting a white micro LED with a diameter of 0.6 mm. The LED offers a luminous flux of 0.6 lm of white light with a blue peak @ 450 nm and a yellow peak @ 555 nm. The presented prototypes fit through a standard 23 G trocar and are the first intraocular light sources worldwide. Two different single-use approaches have already been developed: a handguided and a chandelier device. The hand-guided applicator enables a directly navigation and illumination up to a working distance of 6 mm. The chandelier device is much smaller and does not need an active navigation of the light cone. The brightness and homogeneity of the illumination of these LED devices have been successfully tested on porcine eyes. Presented measurements and calculations prove that even for high LED currents and small distances to the retina these intraocular micro LED devices expose the retina to less hazard than conventional illumination sources like fiber based xenon systems. Even under the worst circumstances application durations of 180 hours would be justifiable.

Effects of solar PAR and UV radiation on tropical biofouling communities

KAUST Repository

Dobretsov, SV

2010-03-08

We investigated the effect of solar ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) on the development of tropical micro- and macrofouling communities for 30 d. The experimental design involved 3 treatments: full spectrum (PAR+UVR), PAR only, and minimal light (reduced PAR and UVR). Terminal restriction fragment length polymorphism analysis demonstrated that different light conditions resulted in the formation of highly different microbial communities. The lowest densities of bacteria were found under the full spectrum treatment, while the lowest densities of diatoms were found in the minimal light treatment. Macrofouling communities consisted of 13 species and differed among light treatments. In the presence of UVR, communities had low species diversity, evenness, and richness, while in minimal light and PAR treatments, communities had high species diversity, evenness, and richness. Similarity percentage (SIMPER) analysis revealed that the tubeworm Hydroides elegans, the alga Ulva (Enteromorpha) sp., and the bivalve Perna viridis were the species responsible for most of the dissimilarities in macrofouling communities among treatments. While densities of H. elegans were similar in the PAR and minimal light treatments, this polychaete had higher growth rates under minimal light conditions. We conclude that UVR and PAR directly control the development of shallow micro- and macrofouling communities by inhibiting the recruitment and growth of sensitive species and promoting the growth of resistant species, but also that these forms of solar radiation influence the surface cues available to competent larvae by altering the development of the microbial community.

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

Science.gov (United States)

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 (pleakage 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.

Variability in coiling technique in LBK pottery inferred by experiments and pore structure micro-tomography analysis

Czech Academy of Sciences Publication Activity Database

Neumannová, Klára; Petřík, J.; Vostrovská, I.; Dvořák, J.; Zikmund, T.; Kaiser, J.

2017-01-01

Roč. 69, č. 2 (2017), s. 172-186 ISSN 0323-1267 R&D Projects: GA ČR(CZ) GA14-07062S Grant - others:GA MŠk(CZ) LQ1601; GA ČR(CZ) GA17-11711S Program:LQ; GA Institutional support: RVO:67985912 Keywords : forming techniques * micro-tomography * Neolithic * Linear Pottery culture (LBK) Subject RIV: AC - Archeology, Anthropology, Ethnology OBOR OECD: Archaeology

Identification of strain fields in pure Al and hybrid Ni/Al metal foams using X-ray micro-tomography under loading

International Nuclear Information System (INIS)

Fíla, T.; Jiroušek, O.; Jung, A.; Kumpová, I.

2016-01-01

Hybrid foams are materials formed by a core from a standard open cell metal foam that is during the process of electrodeposition coated by a thin layer of different nanocrystalline metals. The material properties of the base metal foam are in this way modified resulting in higher plateau stress and, more importantly, by introduction of strain-rate dependence to its deformation response. In this paper, we used time-lapse X-ray micro-tomography for the mechanical characterization of Ni/Al hybrid foams (aluminium open cell foams with nickel coating layer). To fully understand the effects of the coating layer on the material's effective properties, we compared the compressive response of the base uncoated foam to the response of the material with coating thickness of 50 and 75 μm. Digital volume correlation (DVC) was applied to obtain volumetric strain fields of the deforming micro-structure up to the densification region of the deforming cellular structure. The analysis was performed as a compressive mechanical test with simultaneous observation using X-ray radiography and tomography. A custom design experimental device was used for compression of the foam specimens in several deformation states directly in the X-ray setup. Planar X-ray images were taken during the loading phases and a X-ray tomography was performed at the end of each loading phase (up to engineering strain 22%). The samples were irradiated using micro-focus reflection type X-ray tube and images were taken using a large area flat panel detector. Tomography reconstructions were used for an identification of a strain distribution in the foam using digital volumetric correlation. A comparison of the deformation response of the coated and the uncoated foam in uniaxial quasi-static compression is summarized in the paper.

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

Science.gov (United States)

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.

Processing of Bi-2212 and Nb$_3$Sn studied in situ by high energy synchrotron diffraction and micro-tomography

CERN Document Server

Kadar, Julian

Next generation superconducting wires have been studied to obtain more information on the evolution of phase growth, crystallite size and strain state during wire processing. The high energy scattering beam line ID15 at the European Synchrotron Radiation Facility provides a very high flux of high energy photons for very fast in situ X-ray diffraction and micro-tomography studies of Bi-2212/Ag and Nb$_3$S/Cu wire samples. The typical wire processing conditions could be imitated in the X-ray transparent furnace at ID15 for diffraction and tomography studies. Efficient data analysis is mandatory in order to handle the very fast data acquisition rate. For this purpose an Excel-VBA based program was developed that allows a semi-automated fitting and tracking of peaks with pre-set constraints. With this method, more than one thousand diffraction patterns have been analysed to extract d-spacing, peak intensity and peak width values. X ray absorption micro tomograms were recorded simultaneously with the X-ray diffrac...

Micro-computed tomography and bond strength analysis of different root canal filling techniques

Directory of Open Access Journals (Sweden)

Juliane Nhata

2014-01-01

Full Text Available Introduction: The aim of this study was to evaluate the quality and bond strength of three root filling techniques (lateral compaction, continuous wave of condensation and Tagger′s Hybrid technique [THT] using micro-computed tomography (CT images and push-out tests, respectively. Materials and Methods: Thirty mandibular incisors were prepared using the same protocol and randomly divided into three groups (n = 10: Lateral condensation technique (LCT, continuous wave of condensation technique (CWCT, and THT. All specimens were filled with Gutta-percha (GP cones and AH Plus sealer. Five specimens of each group were randomly chosen for micro-CT analysis and all of them were sectioned into 1 mm slices and subjected to push-out tests. Results: Micro-CT analysis revealed less empty spaces when GP was heated within the root canals in CWCT and THT when compared to LCT. Push-out tests showed that LCT and THT had a significantly higher displacement resistance (P < 0.05 when compared to the CWCT. Bond strength was lower in apical and middle thirds than in the coronal thirds. Conclusions: It can be concluded that LCT and THT were associated with higher bond strengths to intraradicular dentine than CWCT. However, LCT was associated with more empty voids than the other techniques.

Urokinase-type plasminogen activator receptor (uPAR) as a promising new imaging target

DEFF Research Database (Denmark)

Persson, Morten; Kjaer, Andreas

2013-01-01

modalities such as optical imaging, magnetic resonance imaging, single photon emission computer tomography (SPECT) and positron emission topography (PET). In this review, we will discuss recent advances in the development of uPAR-targeted imaging ligands according to imaging modality. In addition, we...... will discuss the potential future clinical application for uPAR imaging as a new imaging biomarker....

Quantitative Analysis of Micro-Structure in Meat Emulsions from Grating-Based Multimodal X-Ray Tomography

DEFF Research Database (Denmark)

Einarsdottir, Hildur; Nielsen, Mikkel Schou; Miklos, Rikke

2013-01-01

Using novel X-ray techniques, based on grating-interferometry, new imaging modalities can be obtained simultaneously with absorption computed tomography (CT). These modalities, called phase contrast and dark field imaging, measure the electron density and the diffusion length of the sample....... Enhanced contrast capabilities of this X-ray technique makes studies on materials with similar attenuation properties possible. In this paper the focus is set on processing grating-based X-ray tomograms of meat emulsions to quantitatively measure micro-structural changes due to heat treatment. The emulsion...... samples were imaged both in a raw and cooked state. Additionally, different fat types were used in the emulsions in order to compare micro-structural differences when either pork fat or sunflower oil was used. From the reconstructed tomograms the different ingredients in the emulsions were segmented using...

Effectiveness of rosiglitazone on bleomycin-induced lung fibrosis: Assessed by micro-computed tomography and pathologic scores

International Nuclear Information System (INIS)

Jin, Gong Yong; Bok, Se Mi; Han, Young Min; Chung, Myung Ja; Yoon, Kwon-Ha; Kim, So Ri; Lee, Yong Chul

2012-01-01

Peroxisome proliferator-activated receptor-γ (PPARγ) agonists exhibit potent anti-fibrotic effects in the lung and other tissues. Recently, micro-computed tomography (CT) has been a useful tool for the investigation of lung diseases in small animals and is now increasingly applied to visualize and quantify the pulmonary structures. However, there is little information on the assessment for therapeutic effects of PPARγ agonists on the pulmonary fibrosis in mice using micro-CT. This study was aimed to determine the capability of micro-CT in examining the effects of rosiglitazone on pulmonary fibrosis. We used a murine model of bleomycin-induced lung fibrosis to evaluate the feasibility of micro-CT in evaluating the therapeutic potential of rosiglitazone on pulmonary fibrosis, comparing with pathologic scores. On micro-CT findings, ground glass opacity (80%) and consolidation (20%) were observed predominantly at 3 weeks after the instillation of bleomycin, and the radiologic features became more complex at 6 weeks. In bleomycin-instilled mice treated with rosiglitazone, the majority (80%) showed normal lung features on micro-CT. Radiological-pathologic correlation analyses revealed that ground glass opacity and consolidation were correlated closely with acute inflammation, while reticular opacity was well correlated with histological honeycomb appearance. These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis in mice and that the visualization of bleomycin-induced pulmonary fibrosis using micro-CT is satisfactory to assess the effects of rosiglitazone. It implies that micro-CT can be applied to evaluate therapeutic efficacies of a variety of candidate drugs for lung diseases.

Effectiveness of rosiglitazone on bleomycin-induced lung fibrosis: Assessed by micro-computed tomography and pathologic scores

Energy Technology Data Exchange (ETDEWEB)

Jin, Gong Yong; Bok, Se Mi; Han, Young Min [Department of Radiology, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Chung, Myung Ja [Department of Pathology, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Yoon, Kwon-Ha [Department of Radiology, Iksan Hospital, Iksan (Korea, Republic of); Kim, So Ri [Department of Internal Medicine and Research Center for Pulmonary Disorders, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Lee, Yong Chul, E-mail: leeyc@jbnu.ac.kr [Department of Internal Medicine and Research Center for Pulmonary Disorders, Chonbuk National University Medical School, Jeonju (Korea, Republic of)

2012-08-15

Peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) agonists exhibit potent anti-fibrotic effects in the lung and other tissues. Recently, micro-computed tomography (CT) has been a useful tool for the investigation of lung diseases in small animals and is now increasingly applied to visualize and quantify the pulmonary structures. However, there is little information on the assessment for therapeutic effects of PPAR{gamma} agonists on the pulmonary fibrosis in mice using micro-CT. This study was aimed to determine the capability of micro-CT in examining the effects of rosiglitazone on pulmonary fibrosis. We used a murine model of bleomycin-induced lung fibrosis to evaluate the feasibility of micro-CT in evaluating the therapeutic potential of rosiglitazone on pulmonary fibrosis, comparing with pathologic scores. On micro-CT findings, ground glass opacity (80%) and consolidation (20%) were observed predominantly at 3 weeks after the instillation of bleomycin, and the radiologic features became more complex at 6 weeks. In bleomycin-instilled mice treated with rosiglitazone, the majority (80%) showed normal lung features on micro-CT. Radiological-pathologic correlation analyses revealed that ground glass opacity and consolidation were correlated closely with acute inflammation, while reticular opacity was well correlated with histological honeycomb appearance. These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis in mice and that the visualization of bleomycin-induced pulmonary fibrosis using micro-CT is satisfactory to assess the effects of rosiglitazone. It implies that micro-CT can be applied to evaluate therapeutic efficacies of a variety of candidate drugs for lung diseases.

A method for three-dimensional analysis of the root canal system, before and after mechanical instrumentation, using X-ray Micro-computed tomography

DEFF Research Database (Denmark)

Markvart, Merete; Bjørndal, Lars; Larsen, Per

. Extracted molar teeth were embedded in resin and kept moisturized. Each root canal was instrumented with NiTi instruments to #40. The teeth were scanned before and after instrumentation, using a microCT40 micro-tomography (SCANCO Medical AG, Bassersdorf, Switzerland). The reconstructed slices were imported......Clinical studies have shown a connection between the reduction of micro-organisms in the root canal and the degree of apical enlargement. The aim of this study was to create a non-invasive 3D model for monitoring the apical enlargement in molar teeth before and after mechanical instrumentation...

X-ray micro computed tomography characterization of cellular SiC foams for their applications in chemical engineering

Energy Technology Data Exchange (ETDEWEB)

Ou, Xiaoxia [School of Chemical Engineering and Analytical Science, The University of Manchester, M13 9PL (United Kingdom); Zhang, Xun; Lowe, Tristan [Henry Moseley X-ray Imaging Facility, Materials Science Centre, School of Materials, The University of Manchester, M13 9PL (United Kingdom); Blanc, Remi [FEI, 3 Impasse Rudolf Diesel, BP 50227, 33708 Mérignac (France); Rad, Mansoureh Norouzi [School of Chemical Engineering and Analytical Science, The University of Manchester, M13 9PL (United Kingdom); Wang, Ying [Henry Moseley X-ray Imaging Facility, Materials Science Centre, School of Materials, The University of Manchester, M13 9PL (United Kingdom); Batail, Nelly; Pham, Charlotte [SICAT SARL, 20 Place des Halles, 67000 Strasbourg (France); Shokri, Nima; Garforth, Arthur A. [School of Chemical Engineering and Analytical Science, The University of Manchester, M13 9PL (United Kingdom); Withers, Philip J. [Henry Moseley X-ray Imaging Facility, Materials Science Centre, School of Materials, The University of Manchester, M13 9PL (United Kingdom); Fan, Xiaolei, E-mail: xiaolei.fan@manchester.ac.uk [School of Chemical Engineering and Analytical Science, The University of Manchester, M13 9PL (United Kingdom)

2017-01-15

Open-cell SiC foams clearly are promising materials for continuous-flow chemical applications such as heterogeneous catalysis and distillation. X-ray micro computed tomography characterization of cellular β-SiC foams at a spatial voxel size of 13.6{sup 3} μm{sup 3} and the interpretation of morphological properties of SiC open-cell foams with implications to their transport properties are presented. Static liquid hold-up in SiC foams was investigated through in-situ draining experiments for the first time using the μ-CT technique providing thorough 3D information about the amount and distribution of liquid hold-up inside the foam. This will enable better modeling and design of structured reactors based on SiC foams in the future. In order to see more practical uses, μ-CT data of cellular foams must be exploited to optimize the design of the morphology of foams for a specific application. - Highlights: •Characterization of SiC foams using novel X-ray micro computed tomography. •Interpretation of structural properties of SiC foams regarding to their transport properties. •Static liquid hold-up analysis of SiC foams through in-situ draining experiments.

Improved positron emission tomography imaging of glioblastoma cancer using novel ⁶⁸Ga-labeled peptides targeting the urokinase-type plasminogen activator receptor (uPAR)

DEFF Research Database (Denmark)

Loft, Mathias Dyrberg; Sun, Yao; Liu, Changhao

2017-01-01

for non-invasive positron emission tomography (PET) imaging of uPAR. Despite the optimal physical properties of68Ga for peptide-based PET imaging, low tumor uptakes have previously been reported using68Ga-labeled AE105-NH2-based tracers. In an attempt to optimize the tumor uptake, we developed three novel...... to the non-spacer version, NODAGA-AE105-NH2. Following radiolabeling with68Ga, we evaluated the in vitro and in vivo performance in mice bearing subcutaneous tumors derived from the uPAR-expressing human GBM cell line U87MG. In vivo PET/CT imaging showed that introduction of PEG spacers more than doubled...... confirmed the improved tumor uptakes of the PEG-modified tracers.68Ga-NODAGA-PEG8-AE105-NH2is thus a promising candidate for human translation for PET imaging of GBM....

A Micro-Computed Tomography Technique to Study the Quality of Fibre Optics Embedded in Composite Materials

Directory of Open Access Journals (Sweden)

Gabriele Chiesura

2015-05-01

Full Text Available Quality of embedment of optical fibre sensors in carbon fibre-reinforced polymers plays an important role in the resultant properties of the composite, as well as for the correct monitoring of the structure. Therefore, availability of a tool able to check the optical fibre sensor-composite interaction becomes essential. High-resolution 3D X-ray Micro-Computed Tomography, or Micro-CT, is a relatively new non-destructive inspection technique which enables investigations of the internal structure of a sample without actually compromising its integrity. In this work the feasibility of inspecting the position, the orientation and, more generally, the quality of the embedment of an optical fibre sensor in a carbon fibre reinforced laminate at unit cell level have been proven.

Chaire de microbiologie et maladies infectieuses

OpenAIRE

Sansonetti, Philippe

2010-01-01

Extrait de la leçon inaugurale :« Dès que les êtres vivants sont devenus multicellulaires, ils ont dû socialiser avec les microbes, premiers occupants de la planète, et établir avec eux un état de commensalisme, voire de symbiose. Les êtres multicellulaires modèles, le vers Caenorhabditis, la mouche Drosophila, ont un microbiote commensal – [...] la flore microbienne résidente – et sont sensibles à des pathogènes. Les systèmes gouvernant la gestion de cette interface, nés de l’adaptation de m...

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

International Nuclear Information System (INIS)

Moding, Everett J.; Clark, Darin P.; Qi, Yi; Li, Yifan; Ma, Yan; Ghaghada, Ketan; Johnson, G. Allan; Kirsch, David G.; Badea, Cristian T.

2013-01-01

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 day 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 2 =0.53) and dextran accumulation (R 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

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

Energy Technology Data Exchange (ETDEWEB)

C Hann; M Bentley; A Vercnocke; E Ritman; M Fautsch

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 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 {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.

Cone-beam micro computed tomography dedicated to the breast.

Science.gov (United States)

Sarno, Antonio; Mettivier, Giovanni; Di Lillo, Francesca; Cesarelli, Mario; Bifulco, Paolo; Russo, Paolo

2016-12-01

We developed a scanner for micro computed tomography dedicated to the breast (BµCT) with a high resolution flat-panel detector and a microfocus X-ray tube. We evaluated the system spatial resolution via the 3D modulation transfer function (MTF). In addition to conventional absorption-based X-ray imaging, such a prototype showed capabilities for propagation-based phase-contrast and related edge enhancement effects in 3D imaging. The system limiting spatial resolution is 6.2mm -1 (MTF at 10%) in the vertical direction and 3.8mm -1 in the radial direction, values which compare favorably with the spatial resolution reached by mini focus breast CT scanners of other groups. The BµCT scanner was able to detect both microcalcification clusters and masses in an anthropomorphic breast phantom at a dose comparable to that of two-view mammography. The use of a breast holder is proposed in order to have 1-2min long scan times without breast motion artifacts. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Prediction of primary breast cancer size and T-stage using micro-computed tomography in lumpectomy specimens

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Wafa M Sarraj

2015-01-01

Full Text Available Background: Histopathology is the only accepted method to measure and stage the breast tumor size. However, there is a need to find another method to measure and stage the tumor size when the pathological assessment is not available. Micro-computed tomography. (micro-CT has the ability to measure tumor in three dimensions in an intact lumpectomy specimen. In this study, we aimed to determine the accuracy of micro-CT to measure and stage the primary tumor size in breast lumpectomy specimens, as compared to the histopathology. Materials and Methods: Seventy-two women who underwent lumpectomy surgery at the Massachusetts General Hospital Department of Surgery from June 2011 to September 2011, and from August 2013 to December 2013 participated in this study. The lumpectomy specimens were scanned using micro-CT followed by routine pathological processing. The maximum dimension of the invasive breast tumor was obtained from the micro-CT image and was compared to the corresponding pathology report for each subject. Results: The invasive tumor size measurement by micro-CT was underestimated in 24. cases. (33%, overestimated in 37. cases. (51%, and matched it exactly in 11. cases. (15% compared to the histopathology measurement for all the cases. However, micro-CT T.stage classification differed from histopathology in only 11. (15.2% with 6. cases. (8.3% classified as a higher stage by micro-CT, and 5. cases. (6.9% classified as lower compared to histopathology. In addition, micro-CT demonstrated a statically significant strong agreement (κ =0.6, P < 0.05 with pathological tumor size and staging for invasive ductal carcinoma. (IDC group. In contrast, there was no agreement. (κ = .2, P = 0.67 between micro-CT and pathology in estimating and staging tumor size for invasive lobular carcinoma. (ILC group. This could be explained by a small sample size. (7 for ILC group. Conclusions: Micro-CT is a promising modality for measuring and staging the IDC.

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

Science.gov (United States)

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.

Transverse Micro-structuring of Photonic Crystal Fibers for Industrial Sensors and Side Viewing Probes for Optical Coherence Tomography Applications

Directory of Open Access Journals (Sweden)

Sanjay KHER

2010-05-01

Full Text Available In this work, we report a simple and easily adaptable technique of lateral micro-machining of Photonic Crystal fibers (PCFs using modulated CO2-laser in conjunction with electrical arc system. The technique is controlled, convenient and precise over wide dimensions (50-250 mm. Lateral access to the holes of PCF provides additional flexibility for sensitive real time detection of gases such as green-house gases. Long period gratings are made in PCF through inscription of micro-grooves for sensitive detection of longitudinal strain. A unique and versatile PCF based probe for possible endoscopic Optical Coherence Tomography (OCT applications is reported.

Automatic quantitative micro-computed tomography evaluation of angiogenesis in an axially vascularized tissue-engineered bone construct.

Science.gov (United States)

Arkudas, Andreas; Beier, Justus Patrick; Pryymachuk, Galyna; Hoereth, Tobias; Bleiziffer, Oliver; Polykandriotis, Elias; Hess, Andreas; Gulle, Heinz; Horch, Raymund E; Kneser, Ulrich

2010-12-01

We invented an automatic observer-independent quantitative method to analyze vascularization using micro-computed tomography (CT) along with three-dimensional (3D) reconstruction in a tissue engineering model. An arteriovenous loop was created in the medial thigh of 30 rats and was placed in a particulated porous hydroxyapatite and beta-tricalcium phosphate matrix, filled with fibrin (10 mg/mL fibrinogen and 2 IU/mL thrombin) without (group A) or with (group B) application of fibrin-gel-immobilized angiogenetic growth factors vascular endothelial growth factor (VEGF¹⁶⁵) and basic fibroblast growth factor (bFGF). The explantation intervals were 2, 4, and 8 weeks. Specimens were investigated by means of micro-CT followed by an automatic 3D analysis, which was correlated to histomorphometrical findings. In both groups, the arteriovenous loop led to generation of dense vascularized connective tissue with differentiated and functional vessels inside the matrix. Quantitative analysis of vascularization using micro-CT showed to be superior to histological analysis. The micro-CT analysis also allows the assessment of different other, more complex vascularization parameters within 3D constructs, demonstrating an early improvement of vascularization by application of fibrin-gel-immobilized VEGF¹⁶⁵ and bFGF. In this study quantitative analysis of vascularization using micro-CT along with 3D reconstruction and automatic analysis exhibit to be a powerful method superior to histological evaluation of cross sections.

Effects of solar PAR and UV radiation on tropical biofouling communities

KAUST Repository

Dobretsov, SV; Gosselin, L; Qian, P

2010-01-01

We investigated the effect of solar ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) on the development of tropical micro- and macrofouling communities for 30 d. The experimental design involved 3 treatments: full spectrum

Quantitative analysis of cholesteatoma using high resolution computed tomography

International Nuclear Information System (INIS)

Kikuchi, Shigeru; Yamasoba, Tatsuya; Iinuma, Toshitaka.

1992-01-01

Seventy-three cases of adult cholesteatoma, including 52 cases of pars flaccida type cholesteatoma and 21 of pars tensa type cholesteatoma, were examined using high resolution computed tomography, in both axial (lateral semicircular canal plane) and coronal sections (cochlear, vestibular and antral plane). These cases were classified into two subtypes according to the presence of extension of cholesteatoma into the antrum. Sixty cases of chronic otitis media with central perforation (COM) were also examined as controls. Various locations of the middle ear cavity were measured in terms of size in comparison with pars flaccida type cholesteatoma, pars tensa type cholesteatoma and COM. The width of the attic was significantly larger in both pars flaccida type and pars tensa type cholesteatoma than in COM. With pars flaccida type cholesteatoma there was a significantly larger distance between the malleus and lateral wall of the attic than with COM. In contrast, the distance between the malleus and medial wall of the attic was significantly larger with pars tensa type cholesteatoma than with COM. With cholesteatoma extending into the antrum, regardless of the type of cholesteatoma, there were significantly larger distances than with COM at the following sites: the width and height of the aditus ad antrum, and the width, height and anterior-posterior diameter of the antrum. However, these distances were not significantly different between cholesteatoma without extension into the antrum and COM. The hitherto demonstrated qualitative impressions of bone destruction in cholesteatoma were quantitatively verified in detail using high resolution computed tomography. (author)

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

Science.gov (United States)

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.

Use of micro-tomography for validation of method to identify interfacial shear strength from tensile tests of short regenerated cellulose fibre composites

DEFF Research Database (Denmark)

Hajlane, A.; Miettinen, A.; Madsen, Bo

2016-01-01

The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro......-mechanical model. The parameters characterizing the microstructure of the composites, e.g. fibre length and orientation distributions, used as input in the model were obtained by micro-tomography. The investigation was carried out on composites with untreated and surface treated fibres with various fibre weight...

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

Energy Technology Data Exchange (ETDEWEB)

Moding, Everett J. [Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina (United States); Clark, Darin P.; Qi, Yi [Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States); Li, Yifan; Ma, Yan [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Ghaghada, Ketan [The Edward B. Singleton Department of Pediatric Radiology, Texas Children' s Hospital, Houston, Texas (United States); Johnson, G. Allan [Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States); Kirsch, David G. [Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Badea, Cristian T., E-mail: cristian.badea@duke.edu [Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States)

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 day 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.

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

Science.gov (United States)

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.

Three dimensional imaging of damage in structural materials using high resolution micro-tomography

Energy Technology Data Exchange (ETDEWEB)

Buffiere, J.-Y. [GEMPPM UMR CNRS 5510, INSA Lyon, 20 Av. A. Einstein, 69621 Villeurbanne Cedex (France)]. E-mail: jean-yves.buffiere@insa-lyon.fr; Proudhon, H. [GEMPPM UMR CNRS 5510, INSA Lyon, 20 Av. A. Einstein, 69621 Villeurbanne Cedex (France); Ferrie, E. [GEMPPM UMR CNRS 5510, INSA Lyon, 20 Av. A. Einstein, 69621 Villeurbanne Cedex (France); Ludwig, W. [GEMPPM UMR CNRS 5510, INSA Lyon, 20 Av. A. Einstein, 69621 Villeurbanne Cedex (France); Maire, E. [GEMPPM UMR CNRS 5510, INSA Lyon, 20 Av. A. Einstein, 69621 Villeurbanne Cedex (France); Cloetens, P. [ESRF Grenoble (France)

2005-08-15

This paper presents recent results showing the ability of high resolution synchrotron X-ray micro-tomography to image damage initiation and development during mechanical loading of structural metallic materials. First, the initiation, growth and coalescence of porosities in the bulk of two metal matrix composites have been imaged at different stages of a tensile test. Quantitative data on damage development has been obtained and related to the nature of the composite matrix. Second, three dimensional images of fatigue crack have been obtained in situ for two different Al alloys submitted to fretting and/or uniaxial in situ fatigue. The analysis of those images shows the strong interaction of the cracks with the local microstructure and provides unique experimental data for modelling the behaviour of such short cracks.

Three dimensional imaging of damage in structural materials using high resolution micro-tomography

International Nuclear Information System (INIS)

Buffiere, J.-Y.; Proudhon, H.; Ferrie, E.; Ludwig, W.; Maire, E.; Cloetens, P.

2005-01-01

This paper presents recent results showing the ability of high resolution synchrotron X-ray micro-tomography to image damage initiation and development during mechanical loading of structural metallic materials. First, the initiation, growth and coalescence of porosities in the bulk of two metal matrix composites have been imaged at different stages of a tensile test. Quantitative data on damage development has been obtained and related to the nature of the composite matrix. Second, three dimensional images of fatigue crack have been obtained in situ for two different Al alloys submitted to fretting and/or uniaxial in situ fatigue. The analysis of those images shows the strong interaction of the cracks with the local microstructure and provides unique experimental data for modelling the behaviour of such short cracks

Fixture-abutment connection surface and micro-gap measurements by 3D micro-tomographic technique analysis

Directory of Open Access Journals (Sweden)

Deborah Meleo

2012-01-01

Full Text Available X-ray micro-tomography (micro-CT is a miniaturized form of conventional computed axial tomography (CAT able to investigate small radio-opaque objects at a-few-microns high resolution, in a nondestructive, non-invasive, and tri-dimensional way. Compared to traditional optical and electron microscopy techniques, which provide two-dimensional images, this innovative investigation technology enables a sample tri-dimensional analysis without cutting, coating or exposing the object to any particular chemical treatment. X-ray micro-tomography matches ideal 3D microscopy features: the possibility of investigating an object in natural conditions and without any preparation or alteration; non-invasive, non-destructive, and sufficiently magnified 3D reconstruction; reliable measurement of numeric data of the internal structure (morphology, structure and ultra-structure. Hence, this technique has multi-fold applications in a wide range of fields, not only in medical and odontostomatologic areas, but also in biomedical engineering, materials science, biology, electronics, geology, archaeology, oil industry, and semi-conductors industry. This study shows possible applications of micro-CT in dental implantology to analyze 3D micro-features of dental implant to abutment interface. Indeed, implant-abutment misfit is known to increase mechanical stress on connection structures and surrounding bone tissue. This condition may cause not only screw preload loss or screw fracture, but also biological issues in peri-implant tissues.

Stereological measures of trabecular bone structure: comparison of 3D micro computed tomography with 2D histological sections in human proximal tibial bone biopsies

DEFF Research Database (Denmark)

Thomsen, Jesper Skovhus; Laib, A.; Koller, B.

2005-01-01

Stereology applied on histological sections is the 'gold standard' for obtaining quantitative information on cancellous bone structure. Recent advances in micro computed tomography (microCT) have made it possible to acquire three-dimensional (3D) data non-destructively. However, before the 3D...... methods can be used as a substitute for the current 'gold standard' they have to be verified against the existing standard. The aim of this study was to compare bone structural measures obtained from 3D microCT data sets with those obtained by stereology performed on conventional histological sections...... tibial metaphysis. The biopsies were embedded in methylmetacrylate before microCT scanning in a Scanco microCT 40 scanner at a resolution of 20 x 20 x 20 microm3, and the 3D data sets were analysed with a computer program. After microCT scanning, 16 sections were cut from the central 2 mm of each biopsy...

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

Science.gov (United States)

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.

X-ray micro-tomography investigation of the foaming process in the system of waste glass–silica mud–MnO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Ducman, V., E-mail: vilma.ducman@zag.si [ZAG Ljubljana, Dimičeva 12, 1000 Ljubljana (Slovenia); Korat, L.; Legat, A. [ZAG Ljubljana, Dimičeva 12, 1000 Ljubljana (Slovenia); Mirtič, B. [NTF, Aškerčeva 12, 1000 Ljubljana (Slovenia)

2013-12-15

In case of foamed lightweight aggregates (LWAs), porosity is introduced by the addition of a foaming agent to the glassy matrix, which degasses at an elevated temperature, so that the resulting gases remain trapped inside the glassy structure. The efficiency of action of MnO{sub 2} as a foaming agent in waste glass and waste glass/silica mud systems was studied. Samples were fired at different temperatures and with different dwelling times at a certain temperature, and the development of porosity was investigated by means of X-ray micro-tomography. It was found that, with the prolongation in dwelling times, the number of pores decreased, while, on the other hand, the volume of these pores increased, and that the addition of silica mud increases the foaming temperature and slows down the foaming process. - Highlights: • Preparation of lightweight aggregate from waste glass, silica sludge, and MnO{sub 2} • DTA/TG investigation of MnO{sub 2} • Characterization of pore-forming process by means of X-ray micro-tomography (μcT)

Influencia de los parámetros de proyección por plasma atmosférico en recubrimientos de YSZ obtenidos a partir de polvos micro y nanoestructurados

Directory of Open Access Journals (Sweden)

Carpio, P.

2014-08-01

Full Text Available In the present work, the influence of atmospheric plasma spray (APS parameters on the deposition of two commercial YSZ feedstocks, one conventional and one nanostrcutured, has been studied. First the study focused on how the variability of the different parameters affects the particle behaviour during spraying. For this purpose, a sensor which enables to measure the particle temperature and velocity inside the plasma was used. Once the spraying parameters influence was known, both powders were deposited by APS onto stainless steel substrates modifying the higher influencing parameters. These coatings have been characterised and the influence of the particle behaviour on the coating microstructure and properties has been analysed. This work concludes the spraying parameters variation affects on the particle velocity and temperature inside the plasma plume and this behaviour influences, in turn but in a different way, on the final coating characteristics when using different powders (micro- and nanostructured.En el presente trabajo se ha estudiado la influencia de cada uno de los parámetros de la proyección térmica por plasma atmosférico (atmospheric plasma spraying, APS en la deposición de dos polvos comerciales de YSZ, uno convencional y otro nanoestructurado. En primer lugar se ha estudiado cómo afecta la variabilidad de los diferentes parámetros en el comportamiento de las partículas durante la proyección. Para tal fin, se ha utilizado un sensor que permite determinar la temperatura y la velocidad de las partículas en el interior del plasma. Una vez conocido cómo influyen los parámetros de proyección se han depositado ambos polvos sobre sustratos de acero inoxidable mediante APS modificando aquellos parámetros con un mayor impacto en el comportamiento de las partículas. Estos recubrimientos han sido caracterizados y se ha analizado la influencia del comportamiento de las partículas durante la proyección en la microestructura y

Micro-CT at the imaging beamline P05 at PETRA III

International Nuclear Information System (INIS)

Wilde, Fabian; Ogurreck, Malte; Greving, Imke; Hammel, Jörg U.; Beckmann, Felix; Hipp, Alexander; Lottermoser, Lars; Khokhriakov, Igor; Lytaev, Pavel; Dose, Thomas; Burmester, Hilmar; Müller, Martin; Schreyer, Andreas

2016-01-01

The Imaging Beamline (IBL) P05 is operated by the Helmholtz-Zentrum Geesthacht and located at the DESY storage ring PETRA III. IBL is dedicated to X-ray full field imaging and consists of two experimental end stations. A micro tomography end station equipped for spatial resolutions down to 1 µm and a nano tomography end station for spatial resolutions down to 100 nm. The micro tomography end station is in user operation since 2013 and offers imaging with absorption contrast, phase enhanced absorption contrast and phase contrast methods. We report here on the current status and developments of the micro tomography end station including technical descriptions and show examples of research performed at P05.

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

Science.gov (United States)

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

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

3D observation of the solidified structures by x-ray micro computerized tomography

International Nuclear Information System (INIS)

Yasuda, Hideyuki; Ohnaka, Itsuo; Tsuchiyama, Akira; Nakano, Tsukasa; Uesugi, Kentaro

2003-01-01

The high flux density of the monochromatized and well-collimated X-ray and the high-resolution detector provide a new 3D observation tool for microstructures of metallic alloys and ceramics. The X-ray micro computerized tomography in BL47XU of SPring-8 (SP-μCT) was applied to observe microstructures produced through the eutectic reaction for Sn-based alloys and an Al 2 O 3 -Y 2 O 3 oxide system. The constituent phases in the eutectic structures were three-dimensionally identified, in which the lamellar spacing ranged from several to 10 μm. Since the 3D structure of the unidirectionally solidified specimens contains history of the eutectic structure formation, the 3D structure obtained by SP-μCT gives useful information to consider the microstructure evolution. (author)

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

Science.gov (United States)

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.

From a meso- to micro-scale connectome: Array Tomography and mGRASP

Directory of Open Access Journals (Sweden)

Jinhyun eKim

2015-06-01

Full Text Available Mapping mammalian synaptic connectivity has long been an important goal of neuroscience because knowing how neurons and brain areas are connected underpins an understanding of brain function. Meeting this goal requires advanced techniques with single synapse resolution and large-scale capacity, especially at multiple scales tethering the meso- and micro-scale connectome. Among several advanced LM-based connectome technologies, Array Tomography (AT and mammalian GFP-Reconstitution Across Synaptic Partners (mGRASP can provide relatively high-throughput mapping synaptic connectivity at multiple scales. AT- and mGRASP-assisted circuit mapping (ATing and mGRASPing, combined with techniques such as retrograde virus, brain clearing techniques, and activity indicators will help unlock the secrets of complex neural circuits. Here, we discuss these useful new tools to enable mapping of brain circuits at multiple scales, some functional implications of spatial synaptic distribution, and future challenges and directions of these endeavors.

Application of X-ray computed micro-tomography to the study of damage and oxidation kinetics of thermostructural composites

Energy Technology Data Exchange (ETDEWEB)

Caty, Olivier, E-mail: caty@lcts.u-bordeaux1.fr [Laboratory of Thermostructural Composites (LCTS), Université de Bordeaux, CNRS, SAFRAN, CEA, 3 Allée La Boétie, 33600 Pessac (France); Ibarroule, Philippe; Herbreteau, Mathieu; Rebillat, Francis [Laboratory of Thermostructural Composites (LCTS), Université de Bordeaux, CNRS, SAFRAN, CEA, 3 Allée La Boétie, 33600 Pessac (France); Maire, Eric [MATEIS Laboratory, INSA Lyon, 7 Avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Vignoles, Gérard L. [Laboratory of Thermostructural Composites (LCTS), Université de Bordeaux, CNRS, SAFRAN, CEA, 3 Allée La Boétie, 33600 Pessac (France)

2014-04-01

Thermostructural composites are three-dimensionally (3D) structured materials. Weakening phenomena (mechanical and chemical) take place inside the material following its 3D structure and are thus hard to describe accurately. X-ray computed micro-tomography (μCT) is a recent solution that allows their experimental investigation. The technique is applied here to the study of failure under tensile loading and to the self healing processes during oxidation. Results are useful data to verify or invalidate hypotheses or estimations made in current models.

Technique du Micro-Enseignement: Une Approche Pour Enseigner La Pratique de La Lecture aux Apprenants de Niveau A2 et La Perception de Cette Technique Par Les Futurs Enseignants

Directory of Open Access Journals (Sweden)

Nurten ÖZÇELİK

2017-09-01

Full Text Available Cette étude a été préparée en vue de déterminer les difficultés rencontrées par les futurs enseignants lors de l’enseignement de la lecture aux apprenants de niveau A2 par la technique du micro-enseignement, et de mettre à jour leurs opinions concernant les avantages ainsi que les inconvénients de cette technique. Le groupe de travail est composé de 20 futurs enseignants (14 femmes, 6 hommes du Département de la Didactique du FLE de la Faculté Pédagogique de l’Université Gazi, pour le deuxième semestre de la période 2014-2015. Les données recueillies par les questions à réponses ouvertes ont été évaluées par la méthode de l’analyse descriptive, à la suite des calculs de fréquence. Selon les résultats obtenus, les futurs enseignants ont surtout du mal à prononcer le français, à gérer leurs émotions, à préparer une présentation, des activités de pré-lecture et du dossier de présentation. Augmenter la confiance en soi, apprendre à préparer un plan de cours, donner la possibilité de voir les aspects insuffisants sont les points positifs de la technique. L’insuffisance des participations au cours, l’artificialité du milieu de la classe, la subjectivité des critiques des pairs sont indiqués par les participants comme les inconvénients de cette technique.

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

Science.gov (United States)

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

Micro- and nano-X-ray computed-tomography: A step forward in the characterization of the pore network of a leached cement paste

International Nuclear Information System (INIS)

Bossa, Nathan; Chaurand, Perrine; Vicente, Jérôme; Borschneck, Daniel; Levard, Clément; Aguerre-Chariol, Olivier; Rose, Jérôme

2015-01-01

Pore structure of leached cement pastes (w/c = 0.5) was studied for the first time from micro-scale down to the nano-scale by combining micro- and nano-X-ray computed tomography (micro- and nano-CT). This allowed assessing the 3D heterogeneity of the pore network along the cement profile (from the core to the altered layer) of almost the entire range of cement pore size, i.e. from capillary to gel pores. We successfully quantified an increase of porosity in the altered layer at both resolutions. Porosity is increasing from 1.8 to 6.1% and from 18 to 58% at the micro-(voxel = 1.81 μm) and nano-scale (voxel = 63.5 nm) respectively. The combination of both CT allowed to circumvent weaknesses inherent of both investigation scales. In addition the connectivity and the channel size of the pore network were also evaluated to obtain a complete 3D pore network characterization at both scales

Micro-computerised tomography optimisation for the measurement of bone mineral density around titanium dental implants

International Nuclear Information System (INIS)

Park, C.; Swain, M.; Duncan, W.

2010-01-01

Titanium dental implants (screws) are commonly used to replace missing teeth by forming a biological union with bone ('osseointegration'). Micro-computerised tomography (μCT) may be useful for measuring bone mineral density around dental implants. Major issues arise because of various artefacts that occur with polychromatic X-rays associated bench type instruments that may compromise interpretation of the observations. In this study various approaches to minimise artefacts such as; beam hardening, filtering and edge effects are explored with a homogeneous polymeric material, Teflon, with and without an implant present. The implications of the limitations of using such polychromatic μCT systems to quantify bone mineral density adjacent to the implant are discussed. (author)

Non-destructive morphological observations of the fleshy brittle star, Asteronyx loveni using micro-computed tomography (Echinodermata, Ophiuroidea, Euryalida).

Science.gov (United States)

Okanishi, Masanori; Fujita, Toshihiko; Maekawa, Yu; Sasaki, Takenori

2017-01-01

The first morphological observation of a euryalid brittle star, Asteronyx loveni , using non-destructive X-ray micro-computed tomography (µCT) was performed. The body of euryalids is covered by thick skin, and it is very difficult to observe the ossicles without dissolving the skin. Computed tomography with micrometer resolution (approximately 4.5-15.4 µm) was used to construct 3D images of skeletal ossicles and soft tissues in the ophiuroid's body. Shape and positional arrangement of taxonomically important ossicles were clearly observed without any damage to the body. Detailed pathways inside the vertebral ossicles, lateral arm plates, and arm spines for passage of nerves and water vascular structures were observed. Inter-vertebral muscles were also observed. Forms and 3D arrangements of many important taxonomical characters of the euryalids were scrutinized by µCT in high enough resolution for taxonomic description of ophiuroids.

Non-destructive morphological observations of the fleshy brittle star, Asteronyx loveni using micro-computed tomography (Echinodermata, Ophiuroidea, Euryalida

Directory of Open Access Journals (Sweden)

Massanori Okanishi

2017-03-01

Full Text Available The first morphological observation of a euryalid brittle star, Asteronyx loveni, using non-destructive X-ray micro-computed tomography (µCT was performed. The body of euryalids is covered by thick skin, and it is very difficult to observe the ossicles without dissolving the skin. Computed tomography with micrometer resolution (approximately 4.5–15.4 µm was used to construct 3D images of skeletal ossicles and soft tissues in the ophiuroid’s body. Shape and positional arrangement of taxonomically important ossicles were clearly observed without any damage to the body. Detailed pathways inside the vertebral ossicles, lateral arm plates, and arm spines for passage of nerves and water vascular structures were observed. Inter-vertebral muscles were also observed. Forms and 3D arrangements of many important taxonomical characters of the euryalids were scrutinized by µCT in high enough resolution for taxonomic description of ophiuroids.

Micro-organismes dans les écosystèmes océaniques

National Research Council Canada - National Science Library

Bianchi, Micheline

1989-01-01

... (lagunes et marais, milieu abyssal), dont la specificite a induit des adaptations physiologiques chez les micro-organismes concernes. La quatrieme partie presente certaines des contraintes imposees par la presence de micro-organismes lors de l'utilisation ou de l'exploitation du milieu oceanique.

Diagnostic Value of Ex-Vivo Three-Dimensional Micro-Computed Tomography Imaging of Primary Nonhematopoietic Human Bone Tumors: Osteosarcoma versus Chondrosarcoma

Energy Technology Data Exchange (ETDEWEB)

Langheinrich, A. C.; Stolle, C.; Kampschulte, M.; Lommel, D.; Rau, W. S.; Bassaly, B. (Depts. of Radiology and Pathology, Univ. of Giessen, Giessen (Germany))

2008-10-15

Background: Osteosarcoma and chondrosarcoma are the most common nonhematopoietic primary malignancies of bone. However, unusual radiographic appearances can lead to delay in diagnosis and confusion with benign diseases. Purpose: To evaluate the feasibility of micro-computed tomography (CT) for the analysis of primary, nonhematopoietic human bone tumors ex vivo. Material and Methods: Samples from 12 human bone specimens (osteosarcoma, n=6; chondrosarcoma, n=6) obtained for diagnostic purposes were scanned using industrial X-ray film without amplifier foil and scanned with micro-CT (7- and 12-mum-cubic voxels). Trabecular bone CT 'density' and tumor matrix CT 'density' were determined, and results were compared with those obtained from a detailed conventional histopathologic analysis of corresponding cross-sections. The significance of differences in grayscale measurements was tested with analysis of variance. Results: Micro-CT provided quantitative information on bone morphology equivalent to histopathological analysis. We established grayscale measurements by which tumor matrices of chondrosarcoma and osteosarcoma could be radiographically categorized following histological classifications (P<0.001). Conclusion: Micro-CT is feasible for the analysis and differentiation of human osteosarcoma and chondrosarcoma

Attenuating trabecular morphology associated with low magnesium diet evaluated using micro computed tomography.

Directory of Open Access Journals (Sweden)

Shu-Ju Tu

Full Text Available The literature shows that bone mineral density (BMD and the geometric architecture of trabecular bone in the femur may be affected by inadequate dietary intake of Mg. In this study, we used microcomputed tomography (micro-CT to characterize and quantify the impact of a low-Mg diet on femoral trabecular bones in mice.Four-week-old C57BL/6J male mice were randomly assigned to 2 groups and supplied either a normal or low-Mg diet for 8weeks. Samples of plasma and urine were collected for biochemical analysis, and femur tissues were removed for micro-CT imaging. In addition to considering standard parameters, we regarded trabecular bone as a cylindrical rod and used computational algorithms for a technical assessment of the morphological characteristics of the bones. BMD (mg-HA/cm3 was obtained using a standard phantom.We observed a decline in the total tissue volume, bone volume, percent bone volume, fractal dimension, number of trabecular segments, number of connecting nodes, bone mineral content (mg-HA, and BMD, as well as an increase in the structural model index and surface-area-to-volume ratio in low-Mg mice. Subsequently, we examined the distributions of the trabecular segment length and radius, and a series of specific local maximums were identified. The biochemical analysis revealed a 43% (96% decrease in Mg and a 40% (71% decrease in Ca in plasma (urine excretion.This technical assessment performed using micro-CT revealed a lower population of femoral trabecular bones and a decrease in BMD at the distal metaphysis in the low-Mg mice. Examining the distributions of the length and radius of trabecular segments showed that the average length and radius of the trabecular segments in low-Mg mice are similar to those in normal mice.

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

Science.gov (United States)

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.

La bio-indication de la pollution aquatique par les microalgues (Cas ...

African Journals Online (AJOL)

ecosystCmes et introduisent des micro- organismes pathogmes qui ... organismes vivants dont on connait la sensibilite et les exigences ..... En effet, certains genres proliferent dans des milieux acides, alors que d'autres preferent des milieux alcalins. Par ailleurs, dans les milieux a fortes teneurs en elements acides tel que ...

Assessment of cancellous bone mechanical properties from micro-FE models based on micro-CT, pQCT and MR images.

NARCIS (Netherlands)

Rietbergen, van B.; Majumdar, S.; Pistoia, W.; Newitt, D.C.; Kothari, M.; Laib, A.; Rüegsegger, P.

1998-01-01

Recently, new micro-finite element (micro-FE) techniques have been introduced to calculate cancellous bone mechanical properties directly from high-resolution images of its internal architecture. Also recently, new peripheral quantitative computed tomography (pQCT) and magnetic resonance (MR)

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

Energy Technology Data Exchange (ETDEWEB)

Arifvianto, B., E-mail: b.arifvianto@tudelft.nl; Leeflang, M.A.; Zhou, J.

2016-11-15

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 with 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.

Imaging study of pancreatic ductal adenocarcinomas in Syrian hamsters using X-ray micro-computed tomography (CT)

International Nuclear Information System (INIS)

Kitahashi, Tsukasa; Mutoh, Michihiro; Tsurusaki, Masakatsu

2010-01-01

X-ray computed tomography (CT) has been used for diagnoses of human pancreatic cancer. Although micro-CT is a useful approach to evaluate macromorphology of organs/tissue also in animal models, reports on pancreatic tumors are limited. In this study, the utility of micro-CT was assessed in characterizing chemically induced pancreatic tumors in Syrian hamsters. Hamsters treated with or without N-nitrosobis(2-oxopropyl)amine (BOP) were injected with the antispasmodic agent, scopolamine butylbromide, and contrast agents, 5 or 10 mL/kg body weight of iopamidol or Fenestra VC at 18-38 weeks, then examined by micro-CT scanning with a respiratory gating system. Both peristaltic and respiratory movements were substantially suppressed by the combination of scopolamine butylbromide treatment and the respiratory gating system, resulting in improvements of image qualities. Iopamidol clearly visualized the pancreatic parenchyma and contrasted the margins among the pancreas and other abdominal organs/tissue. Meanwhile Fenestra VC predominantly contrasted abdominal vascular systems, but the margins among pancreas and other organs/tissue remained obscure. Six pancreatic tumors of 4-13 mm in diameter were detected in four of 15 animals, but not the five tumors of 1-4 mm in diameter. The inner tumor images were heterogeneously or uniformly visualized by iopamidol and Fenestra VC. Overall, iopamidol could clearly contrast between pancreatic parenchyma and the tumors as compared with Fenestra VC. All tumors confirmed were histopathologically diagnosed as pancreatic ductal adenocarcinomas. Thus, micro-CT could be useful to evaluate the carcinogenic processes and preventive methods of pancreatic cancer in hamsters and to assess the novel contrast agents for detection of small pancreatic cancer in humans. (author)

Investigation of water and CO2 (carbon dioxide) flooding using micro-CT (micro-computed tomography) images of Berea sandstone core using finite element simulations

International Nuclear Information System (INIS)

Gunde, Akshay C.; Bera, Bijoyendra; Mitra, Sushanta K.

2010-01-01

The present study reports a numerical investigation of water and CO 2 (carbon dioxide) flooding at the pore scale of a porous medium. We use high resolution micro-computed tomography (micro-CT) images of Berea sandstone core to obtain the pore geometry. The numerical solution used for the simulation was carried out by a finite element based software package. Level Set method is used to determine the position of the interface between two immiscible fluids when oil is displaced by water and CO 2 , respectively. The present formulation is validated against single-phase flow through the porous structure. It is found that, fluid flow inside the pore space takes place through preferential inlet and outlet pores. For two-phase flow, it is observed that continuous displacement of oil occurs during water flooding but CO 2 is able to displace oil at certain locations in the pores. Also, the separation of flow front is observed in the case of CO 2 flooding. A quantitative comparison of the results obtained in two types of flooding simulations suggests that water displaces a higher volume of oil than CO 2 in the time period for which the simulations are performed.

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

Directory of Open Access Journals (Sweden)

Saverio Affatato

2017-03-01

Full Text Available 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.

Morphology of Major Stone Types, As Shown by Micro Computed Tomography (micro CT)

International Nuclear Information System (INIS)

Jackson, Molly E.; Beuschel, Christian A.; McAteer, James A.; Williams, James C.

2008-01-01

Micro CT offers the possibility of providing a non-destructive method of stone analysis that allows visualization of 100% of the stone's volume. For the present study, micro CT analysis was completed on stones of known composition with isotropic voxel sizes of either 7 or 9.1 μm. Each mineral type was distinctive, either by x-ray attenuation values or by morphology. Minor components, such as the presence of apatite in oxalate stones, were easily seen. The analysis of stones by micro CT opens up the possibility of exploring the stone as an encapsulated history of the patient's disease, showing changes in mineral deposition with time.

Micro-computed tomography of fatigue microdamage in cortical bone using a barium sulfate contrast agent.

Science.gov (United States)

Leng, Huijie; Wang, Xiang; Ross, Ryan D; Niebur, Glen L; Roeder, Ryan K

2008-01-01

Accumulation of microdamage during fatigue can lead to increased fracture susceptibility in bone. Current techniques for imaging microdamage in bone are inherently destructive and two-dimensional. Therefore, the objective of this study was to image the accumulation of fatigue microdamage in cortical bone using micro-computed tomography (micro-CT) with a barium sulfate (BaSO(4)) contrast agent. Two symmetric notches were machined on the tensile surface of bovine cortical bone beams in order to generate damage ahead of the stress concentrations during four-point bending fatigue. Specimens were loaded to a specified number of cycles or until one notch fractured, such that the other notch exhibited the accumulation of microdamage prior to fracture. Microdamage ahead of the notch was stained in vitro by precipitation of BaSO(4) and imaged using micro-CT. Reconstructed images showed a distinct region of bright voxels around the notch tip or along propagating cracks due to the presence of BaSO(4), which was verified by backscattered electron imaging and energy dispersive spectroscopy. The shape of the stained region ahead of the notch tip was consistent with principal strain contours calculated by finite element analysis. The relative volume of the stained region was correlated with the number of loading cycles by non-linear regression using a power-law. This study demonstrates new methods for the non-destructive and three-dimensional detection of fatigue microdamage accumulation in cortical bone in vitro, which may be useful to gain further understanding into the role of microdamage in bone fragility.

Quantitative in vivo micro-computed tomography for assessment of age-dependent changes in murine whole-body composition

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Kim L. Beaucage

2016-12-01

Full Text Available Micro-computed tomography (micro-CT is used routinely to quantify skeletal tissue mass in small animal models. Our goal was to evaluate repeated in vivo micro-CT imaging for monitoring whole-body composition in studies of growth and aging in mice. Male mice from 2 to 52 weeks of age were anesthetized and imaged using an eXplore Locus Ultra and/or eXplore speCZT scanner. Images were reconstructed into 3D volumes, signal-intensity thresholds were used to classify each voxel as adipose, lean or skeletal tissue, and tissue masses were calculated from known density values. Images revealed specific changes in tissue distribution with growth and aging. Quantification showed biphasic increases in total CT-derived body mass, lean and skeletal tissue masses, consisting of rapid increases to 8 weeks of age, followed by slow linear increases to 52 weeks. In contrast, bone mineral density increased rapidly to a stable plateau at ~14 weeks of age. On the other hand, adipose tissue mass increased continuously with age. A micro-CT-derived total mass was calculated for each mouse and compared with gravimetrically measured mass, which differed on average by <3%. Parameters were highly reproducible for mice of the same age, but variability increased slightly with age. There was also good agreement in parameters for the same group of mice scanned on the eXplore Locus Ultra and eXplore speCZT systems. This study provides reference values for normative comparisons; as well, it demonstrates the usefulness of in vivo single-energy micro-CT scans to quantify whole-body composition in high-throughput studies of growth and aging in mice. Keywords: Adipose tissue, Bone mineral content, Bone mineral density, Growth, Lean tissue, Skeletal tissue

High-frame-rate imaging of biological samples with optoacoustic micro-tomography

Science.gov (United States)

Deán-Ben, X. Luís.; López-Schier, Hernán.; Razansky, Daniel

2018-02-01

Optical microscopy remains a major workhorse in biological discovery despite the fact that light scattering limits its applicability to depths of ˜ 1 mm in scattering tissues. Optoacoustic imaging has been shown to overcome this barrier by resolving optical absorption with microscopic resolution in significantly deeper regions. Yet, the time domain is paramount for the observation of biological dynamics in living systems that exhibit fast motion. Commonly, acquisition of microscopy data involves raster scanning across the imaged volume, which significantly limits temporal resolution in 3D. To overcome these limitations, we have devised a fast optoacoustic micro-tomography (OMT) approach based on simultaneous acquisition of 3D image data with a high-density hemispherical ultrasound array having effective detection bandwidth around 25 MHz. We performed experiments by imaging tissue-mimicking phantoms and zebrafish larvae, demonstrating that OMT can provide nearly cellular resolution and imaging speed of 100 volumetric frames per second. As opposed to other optical microscopy techniques, OMT is a hybrid method that resolves optical absorption contrast acoustically using unfocused light excitation. Thus, no penetration barriers are imposed by light scattering in deep tissues, suggesting it as a powerful approach for multi-scale functional and molecular imaging applications.

Effect of micro-computed tomography voxel size and segmentation method on trabecular bone microstructure measures in mice

Directory of Open Access Journals (Sweden)

Blaine A. Christiansen

2016-12-01

Full Text Available Micro-computed tomography (μCT is currently the gold standard for determining trabecular bone microstructure in small animal models. Numerous parameters associated with scanning and evaluation of μCT scans can strongly affect morphologic results obtained from bone samples. However, the effect of these parameters on specific trabecular bone outcomes is not well understood. This study investigated the effect of μCT scanning with nominal voxel sizes between 6–30 μm on trabecular bone outcomes quantified in mouse vertebral body trabecular bone. Additionally, two methods for determining a global segmentation threshold were compared: based on qualitative assessment of 2D images, or based on quantitative assessment of image histograms. It was found that nominal voxel size had a strong effect on several commonly reported trabecular bone parameters, in particular connectivity density, trabecular thickness, and bone tissue mineral density. Additionally, the two segmentation methods provided similar trabecular bone outcomes for scans with small nominal voxel sizes, but considerably different outcomes for scans with larger voxel sizes. The Qualitatively Selected segmentation method more consistently estimated trabecular bone volume fraction (BV/TV and trabecular thickness across different voxel sizes, but the Histogram segmentation method more consistently estimated trabecular number, trabecular separation, and structure model index. Altogether, these results suggest that high-resolution scans be used whenever possible to provide the most accurate estimation of trabecular bone microstructure, and that the limitations of accurately determining trabecular bone outcomes should be considered when selecting scan parameters and making conclusions about inter-group variance or between-group differences in studies of trabecular bone microstructure in small animals. Keywords: Trabecular bone, Microstructure, Micro-computed tomography, Voxel size, Resolution

Segmentation of Synchrotron Radiation micro-Computed Tomography Images using Energy Minimization via Graph Cuts

International Nuclear Information System (INIS)

Meneses, Anderson A.M.; Giusti, Alessandro; Almeida, André P. de; Nogueira, Liebert; Braz, Delson; Almeida, Carlos E. de; Barroso, Regina C.

2012-01-01

The research on applications of segmentation algorithms to Synchrotron Radiation X-Ray micro-Computed Tomography (SR-μCT) is an open problem, due to the interesting and well-known characteristics of SR images, such as the phase contrast effect. The Energy Minimization via Graph Cuts (EMvGC) algorithm represents state-of-art segmentation algorithm, presenting an enormous potential of application in SR-μCT imaging. We describe the application of the algorithm EMvGC with swap move for the segmentation of bone images acquired at the ELETTRA Laboratory (Trieste, Italy). - Highlights: ► Microstructures of Wistar rats' ribs are investigated with Synchrotron Radiation μCT imaging. ► The present work is part of a research on the effects of radiotherapy on the thoracic region. ► Application of the Energy Minimization via Graph Cuts algorithm for segmentation is described.

Early simultaneous fundus autofluorescence and optical coherence tomography features after pars plana vitrectomy for primary rhegmatogenous retinal detachment.

Science.gov (United States)

Dell'Omo, Roberto; Mura, Marco; Lesnik Oberstein, Sarit Y; Bijl, Heico; Tan, H Stevie

2012-04-01

To describe fundus autofluorescence and optical coherence tomography (OCT) features of the macula after pars plana vitrectomy for rhegmatogenous retinal detachment. Thirty-three eyes of 33 consecutive patients with repaired rhegmatogenous retinal detachment with or without the involvement of the macula were prospectively investigated with simultaneous fundus autofluorescence and OCT imaging using the Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany) within a few weeks after the operation. Fundus autofluorescence imaging of the macula showed lines of increased and decreased autofluorescence in 19 cases (57.6%). On OCT, these lines corresponded to the following abnormalities: outer retinal folds, inner retinal folds, and skip reflectivity abnormalities of the photoreceptor inner segment/outer segment band. Other OCT findings, not related to abnormal lines on fundus autofluorescence, consisted of disruption of photoreceptor inner segment/outer segment band and collection of intraretinal or subretinal fluid. The presence of outer retinal folds significantly related to metamorphopsia but did not relate to poor postoperative visual acuity. Partial-thickness retinal folds occur commonly after vitrectomy for rhegmatogenous retinal detachment repair and may represent an important anatomical substrate for postoperative metamorphopsia. Fundus autofluorescence and OCT are both sensitive techniques for the detection of these abnormalities.

In vitro evaluation of the sinus sagittalis superior thrombosis model in the rat using 3D micro- and nanocomputed tomography

International Nuclear Information System (INIS)

Langheinrich, Alexander Claus; Ostendorf, Anne; Kampschulte, Marian; Yeniguen, Mesut; Marhoffer, Simone; Nedelmann, Max; Stolz, Erwin; Gerriets, Tibo; Dierkes, Christian; Gerlach, Susanne von; Bachmann, Georg

2010-01-01

Thrombosis of the cerebral veins and sinus are common causes of stroke. Animal models help us to understand the underlying pathophysiology of this condition. Therefore, the purpose of our study was to evaluate a well-established model for sinus sagittalis (SSS) thrombosis using micro- and nanocomputed tomography (CT) imaging. SSS thrombosis was performed in four rats. After contrast perfusion, brains were isolated and scanned using micro-CT at (8 μm) 3 voxel size to generate 3D images of the cerebral vasculature. For more detailed information on vascular perfusion territories, nano-CT imaging was performed to investigate the boundary layer of contrast-enhanced vessels and the occluded veins. The venous and arterial vascular volume fraction and gray scale measurements were obtained in the SSS thrombosis group and compared to controls. The significance of differences in vascular volume fraction and gray scale measurements was tested with analysis of variance. Results were complemented with histology. Micro-CT proved to accurately visualize and differentiate vascular occlusion territories performed in the SSS thrombosis model. Moreover, 3D micro-CT provided quantitative information on arterial and venous vascular volume fraction. Micro-CT imaging enables a total 3D visualization of complications (ventricle rupture) in the SSS thrombosis model. We established gray scale measurements by which focal cerebral ischemia could be radiographically categorized (p < 0.001). Using nano-CT, the interface of contrast-perfused and occluded veins can be visualized. Micro-CT is feasible for analysis and differentiation of perfusion territories in an animal model of focal cerebral ischemia. (orig.)

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

Science.gov (United States)

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.

Intraoperative optical coherence tomography in macula involving rhegmatogenous retinal detachment repair with pars plana vitrectomy and perfluoron.

Science.gov (United States)

Toygar, O; Riemann, C D

2016-01-01

PurposeTo investigate microanatomical relationships during surgical repair of macula involving retinal detachment with pars plana vitrectomy (PPV) and perfluoron (PFO) with a microscope-integrated intraoperative optical coherence tomography (iOCT) device.Patients and methodsThis consecutive case series included nine eyes of nine patients with macula involving retinal detachment operated by a single surgeon at the Cincinnati Eye Institute. All patients underwent PPV, PFO injection, endolaser, and air-fluid exchange. The macula was imaged with iOCT before PFO injection, after PFO injection, and after air-fluid exchange in all eyes.ResultsiOCT imaging was ergonomically easy to obtain in all eyes. iOCT clearly demonstrated submacular fluid (SMF) at the beginning of the surgery, macular flattening under PFO in all eyes, small residual SMF under PFO in six of nine eyes, and increased occult SMF following air-fluid exchange in all eyes.ConclusionMicroscope-integrated iOCT is a versatile and powerful imaging modality that holds a great deal of promise in the future. Its confirmation of persistent occult SMF in this small series of macular involving retinal detachment repair with PFO, may inform surgical decision making, and demonstrates a pathophysiological rationale for initial face-down positioning after retinal detachment repair.

Pore-scale study on flow and heat transfer in 3D reconstructed porous media using micro-tomography images

International Nuclear Information System (INIS)

Liu, Zhenyu; Wu, Huiying

2016-01-01

Highlights: • The complex porous domain has been reconstructed with the micro CT scan images. • Pore-scale numerical model based on LB method has been established. • The correlations for flow and heat transfer were derived from the predictions. • The numerical approach developed in this work is suitable for complex porous media. - Abstract: This paper presents the numerical study on fluid flow and heat transfer in reconstructed porous media at the pore-scale with the double-population thermal lattice Boltzmann (LB) method. The porous geometry was reconstructed using micro-tomography images from micro-CT scanner. The thermal LB model was numerically tested before simulation and a good agreement was achieved by compared with the existing results. The detailed distributions of velocity and temperature in complex pore spaces were obtained from the pore-scale simulation. The correlations for flow and heat transfer in the specific porous media sample were derived based on the numerical results. The numerical method established in this work provides a promising approach to predict pore-scale flow and heat transfer characteristics in reconstructed porous domain with real geometrical effect, which can be extended for the continuum modeling of the transport process in porous media at macro-scale.

uPAR Targeted Radionuclide Therapy with 177Lu-DOTA-AE105 Inhibits Dissemination of Metastatic Prostate Cancer

DEFF Research Database (Denmark)

Persson, Morten; Juhl, Karina; Rasmussen, Palle

2014-01-01

The urokinase-type plasminogen activator receptor (uPAR) is implicated in cancer invasion and metastatic development in prostate cancer and provides therefore an attractive molecular target for both imaging and therapy. In this study, we provide the first in vivo data on an antimetastatic effect...... of uPAR radionuclide targeted therapy in such lesions and show the potential of uPAR positron emission tomography (PET) imaging for identifying small foci of metastatic cells in a mouse model of disseminating human prostate cancer. Two radiolabeled ligands were generated in high purity and specific...... value of 100 nM in a competitive binding experiment. In vivo, uPAR targeted radionuclide therapy significantly reduced the number of metastatic lesions in the disseminated metastatic prostate cancer model, when compared to vehicle and nontargeted 177Lu groups (p

Micro-Scale Distribution of CA4+ in Ex Vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging

Science.gov (United States)

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

Micro-Scale Distribution of CA4+ in Ex vivo Human Articular Cartilage Detected with Contrast-Enhanced Micro-Computed Tomography Imaging

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Sakari S. Karhula

2017-08-01

Full Text Available 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, 6 mgI/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

Microcomputed tomography-based assessment of retrieved dental implants

NARCIS (Netherlands)

Narra, N.; Antalainen, A.K.; Zipprich, H.; Sándor, G.K.; Wolff, J.

2015-01-01

Purpose: The aim of this study was to demonstrate the potential of microcomputed tomography (micro-CT) technology in the assessment of retrieved dental implants. Cases are presented to illustrate the value of micro-CT imaging techniques in determining possible mechanical causes for dental implant

Use of Micro-Computed Tomography for Dental Studies in Modern and Fossil Odontocetes: Potential Applications and Limitations

Directory of Open Access Journals (Sweden)

Carolina Loch

2013-10-01

Full Text Available Teeth are important elements in studies of modern and fossil Cetacea (whales, dolphins, providing information on feeding habits, estimations of age and phylogenetic relationships. The growth layer groups (GLGs recorded in dentine have demonstrated application for aging studies, but also have the potential to elucidate life history phenomena such as metabolic or physiologic events. Micro-Computed Tomography (Micro-CT is a non-invasive and non-destructive technique that allows 3-dimensional study of mineralized tissues, such as human teeth, and their physical properties. Teeth from extant dolphins (Cetacea: Odontoceti and some fossil odontocetes were scanned in a Skyscan 1172 Micro-CT desktop system. X-rays were generated at 100 kV and 100 µA for extant samples, and at 80kV and 124 µA for fossils. 0.5 mm thick aluminum and copper filters were used in the beam. Reconstructed images were informative for most extant species, showing a good resolution of the enamel layer, dentine and pulp cavity. Greyscale changes in the dentinal layers were not resolved enough to show GLGs. Visualization of the internal structure in fossil cetacean teeth depended on the degree of diagenetic alteration in the specimen; undifferentiated enamel and dentine regions probably reflect secondary mineralization. However, internal details were finely resolved for one fossil specimen, showing the enamel, internal layers of dentine and the pulp cavity. Micro-CT has been proven to be a useful tool for resolving the internal morphology of fossil and extant teeth of cetaceans before they are sectioned for other morphological analyses; however some methodological refinements are still necessary to allow better resolution of dentine for potential application in non-destructive age determination studies.

Segmentation of Synchrotron Radiation micro-Computed Tomography Images using Energy Minimization via Graph Cuts

Energy Technology Data Exchange (ETDEWEB)

Meneses, Anderson A.M. [Federal University of Western Para (Brazil); Physics Institute, Rio de Janeiro State University (Brazil); Giusti, Alessandro [IDSIA (Dalle Molle Institute for Artificial Intelligence), University of Lugano (Switzerland); Almeida, Andre P. de, E-mail: apalmeid@gmail.com [Physics Institute, Rio de Janeiro State University (Brazil); Nuclear Engineering Program, Federal University of Rio de Janeiro (Brazil); Nogueira, Liebert; Braz, Delson [Nuclear Engineering Program, Federal University of Rio de Janeiro (Brazil); Almeida, Carlos E. de [Radiological Sciences Laboratory, Rio de Janeiro State University (Brazil); Barroso, Regina C. [Physics Institute, Rio de Janeiro State University (Brazil)

2012-07-15

The research on applications of segmentation algorithms to Synchrotron Radiation X-Ray micro-Computed Tomography (SR-{mu}CT) is an open problem, due to the interesting and well-known characteristics of SR images, such as the phase contrast effect. The Energy Minimization via Graph Cuts (EMvGC) algorithm represents state-of-art segmentation algorithm, presenting an enormous potential of application in SR-{mu}CT imaging. We describe the application of the algorithm EMvGC with swap move for the segmentation of bone images acquired at the ELETTRA Laboratory (Trieste, Italy). - Highlights: Black-Right-Pointing-Pointer Microstructures of Wistar rats' ribs are investigated with Synchrotron Radiation {mu}CT imaging. Black-Right-Pointing-Pointer The present work is part of a research on the effects of radiotherapy on the thoracic region. Black-Right-Pointing-Pointer Application of the Energy Minimization via Graph Cuts algorithm for segmentation is described.

Micro-computed tomography of pulmonary fibrosis in mice induced by adenoviral gene transfer of biologically active transforming growth factor-β1

Directory of Open Access Journals (Sweden)

Gauldie Jack

2010-12-01

Full Text Available Abstract Background Micro-computed tomography (micro-CT is a novel tool for monitoring acute and chronic disease states in small laboratory animals. Its value for assessing progressive lung fibrosis in mice has not been reported so far. Here we examined the importance of in vivo micro-CT as non-invasive tool to assess progression of pulmonary fibrosis in mice over time. Methods Pulmonary fibrosis was induced in mice by intratracheal delivery of an adenoviral gene vector encoding biologically active TGF-ß1 (AdTGF-ß1. Respiratory gated and ungated micro-CT scans were performed at 1, 2, 3, and 4 weeks post pulmonary adenoviral gene or control vector delivery, and were then correlated with respective histopathology-based Ashcroft scoring of pulmonary fibrosis in mice. Visual assessment of image quality and consolidation was performed by 3 observers and a semi-automated quantification algorithm was applied to quantify aerated pulmonary volume as an inverse surrogate marker for pulmonary fibrosis. Results We found a significant correlation between classical Ashcroft scoring and micro-CT assessment using both visual assessment and the semi-automated quantification algorithm. Pulmonary fibrosis could be clearly detected in micro-CT, image quality values were higher for respiratory gated exams, although differences were not significant. For assessment of fibrosis no significant difference between respiratory gated and ungated exams was observed. Conclusions Together, we show that micro-CT is a powerful tool to assess pulmonary fibrosis in mice, using both visual assessment and semi-automated quantification algorithms. These data may be important in view of pre-clinical pharmacologic interventions for the treatment of lung fibrosis in small laboratory animals.

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

Science.gov (United States)

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.

Ambient radiation levels in a microPET/CT research laboratory

Energy Technology Data Exchange (ETDEWEB)

Sarmento, D.M.; Rodrigues, D.L.; Sanches, M.P.; Carneiro, J.C.G.G., E-mail: janetegc@ipen.br [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

This study focuses on initial radiological evaluation and the exposure situation related to the worker task in a micro-positron emission tomography/computed tomography laboratory (microPET/CT). Selected and calibrated thermoluminescent dosimeters, TLD, of CaSO{sub 4}:Dy were used to measure room radiation levels. The detectors were placed in several selected points inside the microPET/CT laboratory and adjacent rooms. In addition, the occupationally exposed workers were monthly evaluated for external and internal exposures. In none of the selected points the dose values exceeded the radiation dose limit established for supervised area, as well as the values obtained in individual monitoring. (author)

Ambient radiation levels in a microPET/CT research laboratory

International Nuclear Information System (INIS)

Sarmento, D.M.; Rodrigues, D.L.; Sanches, M.P.; Carneiro, J.C.G.G.

2015-01-01

This study focuses on initial radiological evaluation and the exposure situation related to the worker task in a micro-positron emission tomography/computed tomography laboratory (microPET/CT). Selected and calibrated thermoluminescent dosimeters, TLD, of CaSO 4 :Dy were used to measure room radiation levels. The detectors were placed in several selected points inside the microPET/CT laboratory and adjacent rooms. In addition, the occupationally exposed workers were monthly evaluated for external and internal exposures. In none of the selected points the dose values exceeded the radiation dose limit established for supervised area, as well as the values obtained in individual monitoring. (author)

Positron emission tomography and migraine. Tomographie par emission de positons et migraine

Energy Technology Data Exchange (ETDEWEB)

Chabriat, H. (CEA, 91 - Orsay (France). Service Hospitalier Frederic Joliot)

1992-04-01

Positron emission tomography (PET) is a brain imaging technique that allows in vivo studies of numerous physiological parameters. There have been few PET studies in migraine patients. Cerebral blood flow changes with no variations in brain oxygen consumption have been reported in patients with prolonged neurologic manifestations during migraine attacks. Parenteral administration of reserpine during migraine headache has been followed by a fall in the overall cerebral uptake of glucose. The small sample sizes and a number of methodologic problems complicate the interpretation of these results. Recent technical advances and the development of new PET tracers can be expected to provide further insight into the pathophysiology of migraine. Today cerebral cortex 5 HT{sub 2} serotonin receptors can be studied in migraine patients with PET.

X-ray Micro Tomography as a Tool for Studying Localized Damage / Deformation in Clay Rock

International Nuclear Information System (INIS)

Viggiani, Gioacchino; Besuelle, Pierre; Desrues, Jacques

2013-01-01

Deformation in geo-materials (soils, rocks, concrete, etc.) is often localized, e.g., in the form of shear bands or fractures. In experimental analysis of the mechanical behavior of such materials, standard laboratory methods are insufficient as the majority of measurements are made at the sample scale and rarely at a local scale. X-ray tomography monitoring during loading allows high-resolution full-field observation of the development of deformation. However, such images only indicate clearly the de-formation when there are significant changes in material density (i.e., volume changes) that produce a change in x-ray absorption. As such 3D Digital Image Correlation (DIC) approaches have been developed that allow quantification of the full strain tensor field throughout the imaged volume. This paper presents results from triaxial compression tests on a clay rock (Callovo-Oxfordian argillite) with in situ synchrotron x-ray micro tomography imaging providing complete 3D images of the specimen at several stages throughout the test. These images have been analyzed using 3D DIC to provide full-field displacement and strain measurements, which allowed the detection of the onset of strain localization and its timing relative to the load peak plus insight into the 3D structure of the localized zone. The paper concludes with a few general remarks concerning the lessons learned from this study and perspectives for current and future work. (authors)

Spatial organisation of the ß-globin locus

NARCIS (Netherlands)

R.-J.T.S. Palstra (Robert-Jan)

2005-01-01

textabstractAlle multi-cellulaire organismen beginnen als een enkele bevruchte eicel. Gedurende de differentiatie wordt het aantal cellen vermeerderd door middel van celdeling. De cellen specialiseren zich tevens in verschillende celtypes zoals hersen-, bloed- en spiercellen. Toch bevatten al deze

X-Ray Micro-Computed Tomography of Apollo Samples as a Curation Technique Enabling Better Research

Science.gov (United States)

Ziegler, R. A.; Almeida, N. V.; Sykes, D.; Smith, C. L.

2014-01-01

X-ray micro-computed tomography (micro-CT) is a technique that has been used to research meteorites for some time and many others], and recently it is becoming a more common tool for the curation of meteorites and Apollo samples. Micro-CT is ideally suited to the characterization of astromaterials in the curation process as it can provide textural and compositional information at a small spatial resolution rapidly, nondestructively, and without compromising the cleanliness of the samples (e.g., samples can be scanned sealed in Teflon bags). This data can then inform scientists and curators when making and processing future sample requests for meteorites and Apollo samples. Here we present some preliminary results on micro-CT scans of four Apollo regolith breccias. Methods: Portions of four Apollo samples were used in this study: 14321, 15205, 15405, and 60639. All samples were 8-10 cm in their longest dimension and approximately equant. These samples were micro-CT scanned on the Nikon HMXST 225 System at the Natural History Museum in London. Scans were made at 205-220 kV, 135-160 microamps beam current, with an effective voxel size of 21-44 microns. Results: Initial examination of the data identify a variety of mineral clasts (including sub-voxel FeNi metal grains) and lithic clasts within the regolith breccias. Textural information within some of the lithic clasts was also discernable. Of particular interest was a large basalt clast (approx.1.3 cc) found within sample 60639, which appears to have a sub-ophitic texture. Additionally, internal void space, e.g., fractures and voids, is readily identifiable. Discussion: It is clear from the preliminary data that micro-CT analyses are able to identify important "new" clasts within the Apollo breccias, and better characterize previously described clasts or igneous samples. For example, the 60639 basalt clast was previously believed to be quite small based on its approx.0.5 sq cm exposure on the surface of the main mass

Facture of the Pars Interarticularis with or without Spondylolisthesis in an Adult Population in a Developing Country: Evaluation by Multidetector Computed Tomography

Science.gov (United States)

Khan, Sohail Ahmed; Sattar, Amjad; Khanzada, Usman; Adil, Syed Omair; Hussain, Munawar

2017-01-01

Study Design Descriptive cross-sectional study. Purpose To determine the prevalence of lumbar spondylolysis and spondylolisthesis in a general adult population unrelated to lower back pain as evaluated by multidetector computed tomography. Overview of Literature There is a significant paucity of information related to the prevalence of spondylolysis and spondylolisthesis and its degenerative changes in a general adult population unrelated to lower back pain in developing countries. Methods A retrospective study was conducted on abdominopelvic computed tomography (CT) scans performed between January 1st 2015 and December 31st 2015 for various clinical indications. Patients with lower back pain, with a history of trauma or road traffic accident, or referred from orthopedic or neurosurgery departments were excluded to avoid any bias. CT scans were reviewed in axial, sagittal, and coronal planes using bone window settings for evaluating spondylolysis and spondylolisthesis. Results Of 4,348 patients recruited, spondylolysis and spondylolisthesis were identified in 266 (6.1%) and 142 (3.3%) patients, respectively. Age was significantly higher in both spondylolysis and spondylolisthesis patients than in those without spondylolysis and spondylolisthesis (47.19±15.45 vs. 42.5±15.96, pspondylolysis. Of patients who were >60 years old, both spondylolysis (p=0.018) and spondylolisthesis (p=0.025) were significantly more prevalent in females. Conclusions The prevalence of pars interarticularis fracture observed higher with gradual increase in the prevalence with advancing age. In particular, preponderance was significantly higher among older females. PMID:28670412

Detection of freeze-thaw weathering effect using X-ray micro computed tomography

Science.gov (United States)

Park, J.; Hyun, C.; Park, H.

2011-12-01

Physical weathering caused by repeated freeze-thaw action of water inside rock pores or cracks was artificially simulated in laboratory. The tests were conducted on three rock types, i.e. diorite, basalt, and tuff, which are the major rock types around King Sejong Station of Korea located in Barton Peninsula, King George Island, Antarctica. The temperature of freeze-thaw cycle was also set with simulated the air temperature of the station, i.e. the maximum temperature was + 10 °C and the minimum temperature was - 20 °C. Three cylindrical specimens composed of one for each rock type with 24.6 mm diameter and 14.5 ~ 17.7 mm length were prepared, and 2 mm diameter and 7 mm shallow depth hole was drilled on the center of the specimens. To exaggerate the effect of the freeze-thaw weathering, all tests were conducted under completely saturated condition. 50 cycles of the freeze-thaw test was carried, and X-ray micro computed tomography (CT) images of each rock specimen were obtained after every 10 cycles. Using X-ray micro CT images, 3D structure was rendered and pore and crack structures were extracted. The changes of porosity, absorption rate and pore and crack structure were detected. Porosity of all specimens was decreased linearly and absorption rate of all specimens was increased linearly as weathering processes; the pore connection and crack propagation was detected in 3D rendering pore and crack structure. The change of tuff specimen is the most remarkable among three rock types used in the research, because of its relatively high initial absorption rate and low strength. This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST) (No. 2011-0027520).

Micro-computed tomography-based phenotypic approaches in embryology: procedural artifacts on assessments of embryonic craniofacial growth and development.

Science.gov (United States)

Schmidt, Eric J; Parsons, Trish E; Jamniczky, Heather A; Gitelman, Julian; Trpkov, Cvett; Boughner, Julia C; Logan, C Cairine; Sensen, Christoph W; Hallgrímsson, Benedikt

2010-02-17

Growing demand for three dimensional (3D) digital images of embryos for purposes of phenotypic assessment drives implementation of new histological and imaging techniques. Among these micro-computed tomography (microCT) has recently been utilized as an effective and practical method for generating images at resolutions permitting 3D quantitative analysis of gross morphological attributes of developing tissues and organs in embryonic mice. However, histological processing in preparation for microCT scanning induces changes in organ size and shape. Establishing normative expectations for experimentally induced changes in size and shape will be an important feature of 3D microCT-based phenotypic assessments, especially if quantifying differences in the values of those parameters between comparison sets of developing embryos is a primary aim. Toward that end, we assessed the nature and degree of morphological artifacts attending microCT scanning following use of common fixatives, using a two dimensional (2D) landmark geometric morphometric approach to track the accumulation of distortions affecting the embryonic head from the native, uterine state through to fixation and subsequent scanning. Bouin's fixation reduced average centroid sizes of embryonic mouse crania by approximately 30% and substantially altered the morphometric shape, as measured by the shift in Procrustes distance, from the unfixed state, after the data were normalized for naturally occurring shape variation. Subsequent microCT scanning produced negligible changes in size but did appear to reduce or even reverse fixation-induced random shape changes. Mixtures of paraformaldehyde + glutaraldehyde reduced average centroid sizes by 2-3%. Changes in craniofacial shape progressively increased post-fixation. The degree to which artifacts are introduced in the generation of random craniofacial shape variation relates to the degree of specimen dehydration during the initial fixation. Fixation methods that

Visualization of haemophilic arthropathy in F8(-/-) rats by ultrasonography and micro-computed tomography

DEFF Research Database (Denmark)

Christensen, K R; Roepstorff, K; Petersen, M

2017-01-01

opportunities. Recently, a F8(-/-) rat model of HA was developed. The size of the rat allows for convenient and high resolution imaging of the joints, which could enable in vivo studies of HA development. AIM: To determine whether HA in the F8(-/-) rat can be visualized using ultrasonography (US) and micro......-computed tomography (μCT). METHODS: Sixty F8(-/-) and 20 wild-type rats were subjected to a single or two induced knee bleeds. F8(-/-) rats were treated with either recombinant human FVIII (rhFVIII) or vehicle before the induction of knee bleeds. Haemophilic arthropathy was visualized using in vivo US and ex vivo μCT......, and the observations correlated with histological evaluation. RESULTS: US and μCT detected pathologies in the knee related to HA. There was a strong correlation between disease severity determined by μCT and histopathology. rhFVIII treatment reduced the pathology identified with both imaging techniques. CONCLUSION: US...

Graphite-MicroMégas, a tool for DNA modeling

OpenAIRE

Hornus , Samuel; Larivière , Damien

2011-01-01

National audience; MicroMégas is the current state of an ongoing effort to develop tools for modeling biological assembly of molecules. We here present its DNA modeling part. MicroMégas is implemented as a plug-in to Graphite, which is a research plat- form for computer graphics, 3D modeling and numerical geometry that is developed by members of the ALICE team of INRIA.; Nous décrivons l'outils MicroMégas et les techniques qu'il met en jeu pour la modélisation d'assemblage de molécule, en par...

In vitro ceramic scaffold mineralization: comparison between histological and micro-computed topographical analysis

NARCIS (Netherlands)

Thimm, B.W.; Wechsler, O.; Bohner, M.; Müller, R.; Hofmann, S.

2013-01-01

The porous structure of beta-tricalcium phosphate (b-TCP) scaffolds was assessed by conventional histomor- phometry and micro-computed tomography (micro-CT) to evaluate the substitutability of time-consuming histomor- phometry by rapid micro-CT. Extracellular matrix mineral- ization on human

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

Science.gov (United States)

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.

Contrast enhanced micro-computed tomography resolves the 3-dimensional morphology of the cardiac conduction system in mammalian hearts.

Directory of Open Access Journals (Sweden)

Robert S Stephenson

Full Text Available The general anatomy of the cardiac conduction system (CCS has been known for 100 years, but its complex and irregular three-dimensional (3D geometry is not so well understood. This is largely because the conducting tissue is not distinct from the surrounding tissue by dissection. The best descriptions of its anatomy come from studies based on serial sectioning of samples taken from the appropriate areas of the heart. Low X-ray attenuation has formerly ruled out micro-computed tomography (micro-CT as a modality to resolve internal structures of soft tissue, but incorporation of iodine, which has a high molecular weight, into those tissues enhances the differential attenuation of X-rays and allows visualisation of fine detail in embryos and skeletal muscle. Here, with the use of a iodine based contrast agent (I(2KI, we present contrast enhanced micro-CT images of cardiac tissue from rat and rabbit in which the three major subdivisions of the CCS can be differentiated from the surrounding contractile myocardium and visualised in 3D. Structures identified include the sinoatrial node (SAN and the atrioventricular conduction axis: the penetrating bundle, His bundle, the bundle branches and the Purkinje network. Although the current findings are consistent with existing anatomical representations, the representations shown here offer superior resolution and are the first 3D representations of the CCS within a single intact mammalian heart.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Laboratory micro- and nanoscale X-ray tomographic investigation of Al–7 at.%Cu solidification structures

International Nuclear Information System (INIS)

Patterson, B.M.; Henderson, K.C.; Gibbs, P.J.; Imhoff, S.D.; Clarke, A.J.

2014-01-01

X-ray computed tomography across multiple length scales provides an opportunity to non-destructively visualize and quantify the micro- to nano-scale microstructural features of solidification structures in three dimensions. Aluminum–7 at.%copper samples were directionally solidified at three cooling rates (0.44, 0.67, and 1.33 °C/s), resulting in systematic changes in the as-solidified microstructure, which are difficult to quantify using traditional microscopic techniques. The cooling rate of a material affects its ultimate microstructure, and characterizing that microstructure is key to predicting and understanding its bulk properties. Here, two different laboratory X-ray computed tomography instruments were used to characterize as-solidified microstructures, including micro-scale computed tomography with approximately 1 mm field-of-view, ∼ 1.7 μm resolution, and nano-scale X-ray computed tomography ∼ 65 μm FOV, 150 nm resolution. Micro-scale X-ray radiography and computed tomography enabled a quantitative investigation of changes in the primary dendritic solidification structure with increasing cooling rate. Nano-scale absorption contrast X-ray computed tomography resolved the distinct phases of the lamellar eutectic structure and three dimensional measurements of the ∼ 1 μm interlamellar spacing. It is found that the lamella eutectic structure thickness is inversely proportional to the cooling rate. Nano-scale Zernike phase contrast was also used to image voids at eutectic colony boundaries. The application and resolution of these two instruments are discussed with respect to the resolvable features of the solidification structures. - Highlights: • Al–Cu eutectic is a model system for studying solidification microstructure. • X-ray computed tomography provides a 3D picture of these complex structures. • Micro-scale tomography images the primary and secondary dendritic structures. • Nano-scale tomography images the eutectic lamella and

Laboratory micro- and nanoscale X-ray tomographic investigation of Al–7 at.%Cu solidification structures

Energy Technology Data Exchange (ETDEWEB)

Patterson, B.M., E-mail: bpatterson@lanl.gov; Henderson, K.C.; Gibbs, P.J.; Imhoff, S.D.; Clarke, A.J.

2014-09-15

X-ray computed tomography across multiple length scales provides an opportunity to non-destructively visualize and quantify the micro- to nano-scale microstructural features of solidification structures in three dimensions. Aluminum–7 at.%copper samples were directionally solidified at three cooling rates (0.44, 0.67, and 1.33 °C/s), resulting in systematic changes in the as-solidified microstructure, which are difficult to quantify using traditional microscopic techniques. The cooling rate of a material affects its ultimate microstructure, and characterizing that microstructure is key to predicting and understanding its bulk properties. Here, two different laboratory X-ray computed tomography instruments were used to characterize as-solidified microstructures, including micro-scale computed tomography with approximately 1 mm field-of-view, ∼ 1.7 μm resolution, and nano-scale X-ray computed tomography ∼ 65 μm FOV, 150 nm resolution. Micro-scale X-ray radiography and computed tomography enabled a quantitative investigation of changes in the primary dendritic solidification structure with increasing cooling rate. Nano-scale absorption contrast X-ray computed tomography resolved the distinct phases of the lamellar eutectic structure and three dimensional measurements of the ∼ 1 μm interlamellar spacing. It is found that the lamella eutectic structure thickness is inversely proportional to the cooling rate. Nano-scale Zernike phase contrast was also used to image voids at eutectic colony boundaries. The application and resolution of these two instruments are discussed with respect to the resolvable features of the solidification structures. - Highlights: • Al–Cu eutectic is a model system for studying solidification microstructure. • X-ray computed tomography provides a 3D picture of these complex structures. • Micro-scale tomography images the primary and secondary dendritic structures. • Nano-scale tomography images the eutectic lamella and

Report of radiological safety for a micro PET; Informe de seguridad radiologica para un microPET

Energy Technology Data Exchange (ETDEWEB)

Gallegos M, R.; Ruiz T, C. G.; Martinez D, A.; Rodriguez V, M., E-mail: romeo@fisica.unam.m [UNAM, Instituto de Fisica, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

2010-09-15

Considering one of the guides emitted by the National Commission of Nuclear Security and Safeguards, was realized the report of radiological safety for a micro tomography by positrons emission that is part of Bimodal System of Images developed in their entirety for personnel of the Physics Institute of UNAM. With this system is sought to obtain tomography images of small animals using non destructive methods, such as computerized micro tomography and micro tomography by positrons emission. In this work each one of the report points is enumerated and only it is described, to big features on that consist, due to the great extension of each one of them. The report has two parts; the first is denominated -Of the installation and the Organization- and is given to know the interior and external characteristics of the installation, besides how and under which authority the activities will be executed inside the laboratory. The second part is called -of the Radiological Protection- and has for objective to describe the radiation sources that will be used, as well as the measures of radiological protection foreseen inside the laboratory. The most important part in the report consists on the description of the three radionuclides to use: {sup 18}F, {sup 11}C and {sup 13}N, as well as the methods for the shielding calculation and for the estimate of the dose equivalent during the normal operation of the equipment. These methods were applied three times, because the calculation was made for each radionuclide. The results of these calculations show that: 1) it not is necessary to have a structural shielding, due to the activity sources very reduced, and 2) the dose limit per year (according to the ICRP-60) it will not be surpassed neither in the case of the occupationally exposed personnel, neither on the public in general. (Author

Comparative micro computed tomography study of a vertebral body

Science.gov (United States)

Drews, Susanne; Beckmann, Felix; Herzen, Julia; Brunke, Oliver; Salmon, Phil; Friess, Sebastian; Laib, Andres; Koller, Bruno; Hemberger, Thomas; Müller-Gerbl, Magdalena; Müller, Bert

2008-08-01

Investigations of bony tissues are often performed using micro computed tomography based on X-rays, since the calcium distribution leads to superior contrast. Osteoporotic bone, for example, can be well compared with healthy one with respect to density and morphology. Degenerative and rheumatoid diseases usually start, however, at the bone-cartilage-interface, which is hardly accessible. The direct influence on the bone itself becomes only visible at later stage. For the development of suitable therapies against degenerative cartilage damages the exact three-dimensional description of the bone-cartilage interface is vital, as demonstrated for transplanted cartilage-cells or bone-cartilage-constructs in animal models. So far, the morphological characterization was restricted to magnetic resonance imaging (MRI) with poor spatial resolution or to time-consuming histological sectioning with appropriate spatial resolution only in two rather arbitrarily chosen directions. Therefore, one should develop μCT to extract the features of low absorbing cartilage. The morphology and the volume of the inter-vertebral cartilage disc of lumbar motion segments have been determined for one PMMA embedded specimen. Tomograms were recorded using nanotom® (Phoenix|x-ray, Wunstorf, Germany), μCT 35TM (Scanco Medical, Brütisellen, Switzerland), 1172TM and 1174TM (both Skyscan, Kontich, Belgium), as well as using the SRμCT at HASYLAB/DESY. Conventional and SRμCT can provide the morphology and the volume of cartilage between bones. Increasing the acquisition time, the signal-to-noise ratio becomes better and better but the prominent artifacts in conventional μCT as the result of inhomogeneously distributed bony tissue prevents the exact segmentation of cartilage. SRμCT allows segmenting the cartilage but requires long periods of expensive beam-time to obtain reasonable contrast.

Directed and persistent movement arises from mechanochemistry of the ParA/ParB system.

Science.gov (United States)

Hu, Longhua; Vecchiarelli, Anthony G; Mizuuchi, Kiyoshi; Neuman, Keir C; Liu, Jian

2015-12-22

The segregation of DNA before cell division is essential for faithful genetic inheritance. In many bacteria, segregation of low-copy number plasmids involves an active partition system composed of a nonspecific DNA-binding ATPase, ParA, and its stimulator protein ParB. The ParA/ParB system drives directed and persistent movement of DNA cargo both in vivo and in vitro. Filament-based models akin to actin/microtubule-driven motility were proposed for plasmid segregation mediated by ParA. Recent experiments challenge this view and suggest that ParA/ParB system motility is driven by a diffusion ratchet mechanism in which ParB-coated plasmid both creates and follows a ParA gradient on the nucleoid surface. However, the detailed mechanism of ParA/ParB-mediated directed and persistent movement remains unknown. Here, we develop a theoretical model describing ParA/ParB-mediated motility. We show that the ParA/ParB system can work as a Brownian ratchet, which effectively couples the ATPase-dependent cycling of ParA-nucleoid affinity to the motion of the ParB-bound cargo. Paradoxically, this resulting processive motion relies on quenching diffusive plasmid motion through a large number of transient ParA/ParB-mediated tethers to the nucleoid surface. Our work thus sheds light on an emergent phenomenon in which nonmotor proteins work collectively via mechanochemical coupling to propel cargos-an ingenious solution shaped by evolution to cope with the lack of processive motor proteins in bacteria.

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

Science.gov (United States)

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.

Multiscale Shannon's Entropy Modeling of Orientation and Distance in Steel Fiber Micro-Tomography Data.

Science.gov (United States)

Chiverton, John P; Ige, Olubisi; Barnett, Stephanie J; Parry, Tony

2017-11-01

This paper is concerned with the modeling and analysis of the orientation and distance between steel fibers in X-ray micro-tomography data. The advantage of combining both orientation and separation in a model is that it helps provide a detailed understanding of how the steel fibers are arranged, which is easy to compare. The developed models are designed to summarize the randomness of the orientation distribution of the steel fibers both locally and across an entire volume based on multiscale entropy. Theoretical modeling, simulation, and application to real imaging data are shown here. The theoretical modeling of multiscale entropy for orientation includes a proof showing the final form of the multiscale taken over a linear range of scales. A series of image processing operations are also included to overcome interslice connectivity issues to help derive the statistical descriptions of the orientation distributions of the steel fibers. The results demonstrate that multiscale entropy provides unique insights into both simulated and real imaging data of steel fiber reinforced concrete.

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

Science.gov (United States)

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 sockets in the OVX-saline group increased, but the increase was significantly lower than for the other groups at 4 weeks (P 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 sockets in estrogen-deficient rats and helps resist the loss of alveolar bone adjacent to extraction sockets. Copyright 2010 Mosby, Inc. All rights reserved.

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

Science.gov (United States)

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 (Pvs. (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.

A micro-CL system and its applications

Science.gov (United States)

Wei, Zenghui; Yuan, Lulu; Liu, Baodong; Wei, Cunfeng; Sun, Cuili; Yin, Pengfei; Wei, Long

2017-11-01

The computed laminography (CL) method is preferable to computed tomography for the non-destructive testing of plate-like objects. A micro-CL system is developed for three-dimensional imaging of plate-like objects. The details of the micro-CL system are described, including the system architecture, scanning modes, and reconstruction algorithm. The experiment results of plate-like fossils, insulated gate bipolar translator module, ball grid array packaging, and printed circuit board are also presented to demonstrate micro-CL's ability for 3D imaging of flat specimens and universal applicability in various fields.

Comparison of Direct Pars Repair Techniques of Spondylolysis in Pediatric and Adolescent Patients: Pars Compression Screw Versus Pedicle Screw-Rod-Hook.

Science.gov (United States)

Karatas, Ali F; Dede, Ozgur; Atanda, Alfred A; Holmes, Larry; Rogers, Kenneth; Gabos, Peter; Shah, Suken A

2016-08-01

Retrospective clinical cohort study. To compare the clinical and radiographic outcomes of patients who were treated with intrasegmental pars fixation by either laminar compression screw (LS) or a pedicle screw, rod, and laminar hook (PSRH) construct. Spondylolysis is a nonunion defect of the pars interarticularis. In symptomatic spondylolysis, direct repair of the pars interarticularis defect can preserve motion and prevent abnormal stresses at the adjacent levels. Sixteen patients who failed nonoperative treatment and underwent direct pars repair by using LS (n=9) or PSRH (n=7) constructs were included in the study. Clinical outcome was assessed by using the MacNab criteria. Radiologic fusion and complications were evaluated using plain radiographs or computed tomography images and patient charts. The healing rate was 100% after 6 months. The healing time was similar in both the groups: LS, 6.5 months; PSRH, 6.2 months. Patients with PSRH (5.9 mo) were more likely to return to sports earlier relative to patients with LS (7.7 mo). There were no complications in the LS group; in the PSRH group, 1 patient had mild sensory deficit and 2 had superficial wound infections. The MacNab criteria for pain assessment showed an excellent or good outcome in 8 of 9 patients in LS group and 6 of 7 patients in PSRH group. Relative to LS patients, there was a significant increase in surgical time and estimated blood loss among PSRH patients. Either of the mentioned 2 techniques appears to produce acceptable results. Biplanar fluoroscopy and navigation systems could minimize the risk of screw misplacement with LS construct. Familiarity with the various fixation techniques will allow the surgeon to select the most appropriate surgical technique.

Dosimetry of 64Cu-DOTA-AE105, a PET tracer for uPAR imaging

DEFF Research Database (Denmark)

Persson, Morten; El Ali, Henrik H.; Binderup, Tina

2014-01-01

64Cu-DOTA-AE105 is a novel positron emission tomography (PET) tracer specific to the human urokinase-type plasminogen activator receptor (uPAR). In preparation of using this tracer in humans, as a new promising method to distinguish between indolent and aggressive cancers, we have performed PET...... studies in mice to evaluate the in vivo biodistribution and estimate human dosimetry of 64Cu-DOTA-AE105. MethodsFive mice received iv tail injection of 64Cu-DOTA-AE105 and were PET/CT scanned 1, 4.5 and 22h post injection. Volume-of-interest (VOI) were manually drawn on the following organs: heart, lung......Favorable dosimetry estimates together with previously reported uPAR PET data fully support human testing of 64Cu-DOTA-AE105....

Antibody-based PET of uPA/uPAR signaling with broad applicability for cancer imaging

DEFF Research Database (Denmark)

Yang, Dongzhi; Severin, Gregory; Dougherty, Casey A.

2016-01-01

Mounting evidence suggests that the urokinase plasminogen activator (uPA) and its receptor (uPAR) play a central role in tumor progression. The goal of this study was to develop an 89Zr-labeled, antibody-based positron emission tomography (PET) tracer for quantitative imaging of the uPA/uPAR system....... An anti-uPA monoclonal antibody (ATN-291) was conjugated with a deferoxamine (Df) derivative and subsequently labeled with 89Zr. Flow cytometry, microscopy studies, and competitive binding assays were conducted to validate the binding specificity of Df-ATN-291 against uPA. PET imaging with 89Zr-Df-ATN-291...... was carried out in different tumors with distinct expression levels of uPA. Biodistribution, histology examination, and Western blotting were performed to correlate tumor uptake with uPA or uPAR expression. ATN-291 retained uPA binding affinity and specificity after Df conjugation. 89Zr-labeling of ATN-291...

CERN MicroClub

CERN Multimedia

CERN MicroClub

2016-01-01

Le CERN Micro Club (en partenariat avec Google Education et EU Code Week) organise un évènement éducatif exceptionnel autour de trois kits scientifiques basés sur le mini-ordinateur Raspberry Pi : Le Bras Robotique "Poppy Ergo Jr", conçu par l'équipe-projet Flowers (Centre de recherche Inria Bordeaux Sud-Ouest, ENSTA Paris Tech). Le kit de détection de rayons cosmiques "Muon Hunter", conçu en partenariat entre Mr Mihaly Vadai et les membres du CERN Micro Club. La voiture radio-commandée programmable Wifi "GianoPi", conçue en partenariat avec le campus "La Chataigneraie", pour l'Ecole Internationale de Genève.   Le vendredi 7 octobre (de 18h à 20h) : Une conférence gratuite et ouverte à tous (limitée à 100 personnes), pendant laquelle v...

A nanotube-based field emission x-ray source for microcomputed tomography

International Nuclear Information System (INIS)

Zhang, J.; Cheng, Y.; Lee, Y.Z.; Gao, B.; Qiu, Q.; Lin, W.L.; Lalush, D.; Lu, J.P.; Zhou, O.

2005-01-01

Microcomputed tomography (micro-CT) is a noninvasive imaging tool commonly used to probe the internal structures of small animals for biomedical research and for the inspection of microelectronics. Here we report the development of a micro-CT scanner with a carbon nanotube- (CNT-) based microfocus x-ray source. The performance of the CNT x-ray source and the imaging capability of the micro-CT scanner were characterized

Physical characterization and performance evaluation of an x-ray micro-computed tomography system for dimensional metrology applications

DEFF Research Database (Denmark)

Hiller, Jochen; Maisl, Michael; Reindl, Leonard M

2012-01-01

This paper presents physical and metrological characterization measurements conducted for an industrial x-ray micro-computed tomography (CT) system. As is well known in CT metrology, many factors, e.g., in the scanning and reconstruction process, the image processing, and the 3D data evaluation...... components of a CT scanner, i.e. the x-ray tube and the flat-panel detector, are characterized. The contrast and noise transfer property of the scanner is obtained using image-processing methods based on linear systems theory. A long-term temperature measurement in the scanner cabinet has been carried out....... The dimensional measurement property has been quantified by using a calibrated ball-bar and uncertainty budgeting. Information about the performance of a CT scanner system in terms of contrast and noise transmission and sources of geometrical errors will help plan CT scans more efficiently. In particular...

Accuracy and reliability of different cone beam computed tomography (CBCT) devices for structural analysis of alveolar bone in comparison with multislice CT and micro-CT.

Science.gov (United States)

Van Dessel, Jeroen; Nicolielo, Laura Ferreira Pinheiro; Huang, Yan; Coudyzer, Walter; Salmon, Benjamin; Lambrichts, Ivo; Jacobs, Reinhilde

The aim of this study was to assess whether cone beam computed tomography (CBCT) may be used for clinically reliable alveolar bone quality assessment in comparison to its clinical alternatives, multislice computed tomography and the gold standard (micro-CT). Six dentate mandibular bone samples were scanned with seven CBCT devices (ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170, Carestream 9300, Scanora 3D, I-CAT Next generation), one micro-CT scanner (SkyScan 1174) and one MSCT machine (Somatom Definition Flash) using two protocols (standard and high-resolution). MSCT and CBCT images were automatically spatially aligned on the micro-CT scan of the corresponding sample. A volume of interest was manually delineated on the micro-CT image and overlaid on the other scanning devices. Alveolar bone structures were automatically extracted using the adaptive thresholding algorithm. Based on the resulting binary images, an automatic 3D morphometric quantification was performed in a CT-Analyser (Bruker, Kontich, Belgium). The reliability and measurement errors were calculated for each modality compared to the gold standard micro-CT. Both MSCT and CBCT were associated with a clinically and statistically (P max, bone surface density -0.47 mm-1 min to 0.16 mm-1 max and trabecular thickness 0.15 mm min to 0.31 mm max) were significantly (P max and fractal dimension 0.08 min to 0.17 max) in all scanners compared to micro-CT. However, the structural pattern of the alveolar bone remained similar compared to that of the micro-CT for the ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170 and Carestream 9300. On the other hand, the Scanora 3D, i-CAT Next Generation, standard and high-resolution MSCT displayed an overrated bone quantity and aberrant structural pattern compared to other scanning devices. The calculation of morphometric indices had an overall high reliability (intraclass correlation coefficient [ICC] 0.62 min to 0.99 max), except

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

Science.gov (United States)

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.

Comparison of denture models by means of micro computed tomography

Science.gov (United States)

Vögtlin, Christoph; Schulz, Georg; Deyhle, Hans; Jäger, Kurt; Liebrich, Thomas; Weikert, Sascha; Müller, Bert

2012-10-01

The production of dental inlays and crowns requires precise information on patients' teeth morphology. The conventional method is the preparation of impressions using mold materials, e.g. a silicone impression material. The disadvantage of this technique is the human choke impulse and the flavor of the material. These discomforts can be avoided by methods where a three-dimensional scanner is used for recording the teeth morphology. The present study reveals the accuracy of three model types, namely conventional impression, rapid prototyping using an oral scanner C.O.S., 3M (Schweiz) AG and milling from a proprietary resin using the oral scanner iTero, Straumann Holding AG. For each method five models were fabricated from a steel reference (standard). Using a nanotom m (phoenixǀx-ray, GE Sensing and Inspection Technologies GmbH), three-dimensional micro computed tomography data sets of the standard and the 15 models were recorded and landmark distances within the data sets were measured with sub-pixel accuracy. To verify these results a coordinate measuring machine (Leitz PMM 864, Hexagon Metrology GmbH) based on tactile detection was used for the measurement of the landmark distances, and a correction of the distances measured by the nanotom m was arranged. The nanotom data sets of the 15 models were also compared to the standard by means of a non-rigid registration algorithm. The calculated deformation field exhibited mean pixel displacement values of (0.19 +/- 0.09) mm for the C.O.S. models, (0.12 +/- 0.07) mm for the gypsum models and (0.19 +/- 0.12) mm for the i-Tero models.

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

Science.gov (United States)

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.

FooPar

DEFF Research Database (Denmark)

Hargreaves, F. P.; Merkle, D.

2013-01-01

We present FooPar, an extension for highly efficient Parallel Computing in the multi-paradigm programming language Scala. Scala offers concise and clean syntax and integrates functional programming features. Our framework FooPar combines these features with parallel computing techniques. Foo......, results based on a empirical analysis on two supercomputers are given. We achieve close-to-optimal performance wrt. theoretical peak performance. Based on this result we conclude that FooPar allows programmers to fully access Scalas design features without suffering from performance drops when compared...

The micro-mechanics of strength, durability and damage tolerance in composites: new insights from high resolution computed tomography

Science.gov (United States)

Spearing, S. Mark; Sinclair, Ian

2016-07-01

Recent work, led by the authors, on impact damage resistance, particle toughening and tensile fibre failure is reviewed in order to illustrate the use of high-resolution X-ray tomography to observe and quantify damage mechanisms in carbon fibre composite laminates. Using synchrotron and micro-focus X-ray sources resolutions of less than 1 μm have been routinely achieved. This enables individual broken fibres and the micromechanisms of particle toughening to be observed and quantified. The data for fibre failure, cluster formation and overall tensile strength are compared with model predictions. This allows strategies for future model development to be identified. The overall implications for using such high-resolution 3-D measurements to inform a “data-rich mechanics” approach to materials evaluation and modeling is discussed.

Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

Science.gov (United States)

Baronian, Grégory; Ginda, Katarzyna; Berry, Laurence; Cohen-Gonsaud, Martin; Zakrzewska-Czerwińska, Jolanta; Jakimowicz, Dagmara; Molle, Virginie

2015-01-01

Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system.

Directory of Open Access Journals (Sweden)

Grégory Baronian

Full Text Available Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.

Finite element analysis of the mechanical properties of cellular aluminium based on micro-computed tomography

International Nuclear Information System (INIS)

Veyhl, C.; Belova, I.V.; Murch, G.E.; Fiedler, T.

2011-01-01

Research highlights: → Elastic and plastic anisotropy is observed for both materials → Both show qualitatively similar characteristics with quantitative differences → Distinctly higher mechanical properties for closed-cell foam → The 'big' and 'small' models show good agreement for the closed-cell foam. - Abstract: In the present paper, the macroscopic mechanical properties of open-cell M-Pore sponge (porosity of 91-93%) and closed-cell Alporas foam (porosity of 80-86%) are investigated. The complex geometry of these cellular materials is scanned by micro-computed tomography and used in finite element (FE) analysis. The mechanical properties are determined by uni-axial compression simulations in three perpendicular directions (x-, y- and z-direction). M-Pore and Alporas exhibit the same qualitative mechanical characteristics but with quantitative differences. In both cases, strong anisotropy is observed for Young's modulus and the 0.002 offset yield stress. Furthermore, for the investigated relative density range a linear dependence between relative density and mechanical properties is found. Finally, a distinctly higher Young's modulus and 0.002 offset yield stress is observed for Alporas.

X-ray micro computed tomography for the visualization of an atherosclerotic human coronary artery

Science.gov (United States)

Matviykiv, Sofiya; Buscema, Marzia; Deyhle, Hans; Pfohl, Thomas; Zumbuehl, Andreas; Saxer, Till; Müller, Bert

2017-06-01

Atherosclerosis refers to narrowing or blocking of blood vessels that can lead to a heart attack, chest pain or stroke. Constricted segments of diseased arteries exhibit considerably increased wall shear stress, compared to the healthy ones. One of the possibilities to improve patient’s treatment is the application of nano-therapeutic approaches, based on shear stress sensitive nano-containers. In order to tailor the chemical composition and subsequent physical properties of such liposomes, one has to know precisely the morphology of critically stenosed arteries at micrometre resolution. It is often obtained by means of histology, which has the drawback of offering only two-dimensional information. Additionally, it requires the artery to be decalcified before sectioning, which might lead to deformations within the tissue. Micro computed tomography (μCT) enables the three-dimensional (3D) visualization of soft and hard tissues at micrometre level. μCT allows lumen segmentation that is crucial for subsequent flow simulation analysis. In this communication, tomographic images of a human coronary artery before and after decalcification are qualitatively and quantitatively compared. We analyse the cross section of the diseased human coronary artery before and after decalcification, and calculate the lumen area of both samples.

Hybrid setup for micro- and nano-computed tomography in the hard X-ray range

Science.gov (United States)

Fella, Christian; Balles, Andreas; Hanke, Randolf; Last, Arndt; Zabler, Simon

2017-12-01

With increasing miniaturization in industry and medical technology, non-destructive testing techniques are an area of ever-increasing importance. In this framework, X-ray microscopy offers an efficient tool for the analysis, understanding, and quality assurance of microscopic samples, in particular as it allows reconstructing three-dimensional data sets of the whole sample's volume via computed tomography (CT). The following article describes a compact X-ray microscope in the hard X-ray regime around 9 keV, based on a highly brilliant liquid-metal-jet source. In comparison to commercially available instruments, it is a hybrid that works in two different modes. The first one is a micro-CT mode without optics, which uses a high-resolution detector to allow scans of samples in the millimeter range with a resolution of 1 μm. The second mode is a microscope, which contains an X-ray optical element to magnify the sample and allows resolving 150 nm features. Changing between the modes is possible without moving the sample. Thus, the instrument represents an important step towards establishing high-resolution laboratory-based multi-mode X-ray microscopy as a standard investigation method.

In-situ, real time micro-CT imaging of pore scale processes, the next frontier for laboratory based micro-CT scanning

OpenAIRE

Boone, Marijn; Bultreys, Tom; Masschaele, Bert; Van Loo, Denis; Van Hoorebeke, Luc; Cnudde, Veerle

2016-01-01

Over the past decade, laboratory based X-ray computed micro-tomography (micro-CT) has given unique insights in the internal structure of complex reservoir rocks, improving the understanding of pore scale processes and providing crucial information for pore scale modelling. Especially in-situ imaging using X-ray optimized Hassler type cells has enabled the direct visualization of fluid distributions at the pore scale under reservoir conditions. While sub-micrometre spatial resolutions are achi...

Comparison of surface extraction techniques performance in computed tomography for 3D complex micro-geometry dimensional measurements

DEFF Research Database (Denmark)

Torralba, Marta; Jiménez, Roberto; Yagüe-Fabra, José A.

2018-01-01

micro-geometries as well (i.e., in the sub-mm dimensional range). However, there are different factors that may influence the CT process performance, being one of them the surface extraction technique used. In this paper, two different extraction techniques are applied to measure a complex miniaturized......The number of industrial applications of computed tomography (CT) for dimensional metrology in 100–103 mm range has been continuously increasing, especially in the last years. Due to its specific characteristics, CT has the potential to be employed as a viable solution for measuring 3D complex...... dental file by CT in order to analyze its contribution to the final measurement uncertainty in complex geometries at the mm to sub-mm scales. The first method is based on a similarity analysis: the threshold determination; while the second one is based on a gradient or discontinuity analysis: the 3D...

Attenuation Drift in the Micro-Computed Tomography System at LLNL

Energy Technology Data Exchange (ETDEWEB)

Dooraghi, Alex A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brown, William [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Seetho, Isaac [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kallman, Jeff [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lennox, Kristin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glascoe, Lee [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

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, significantly 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.

ParA and ParB coordinate chromosome segregation with cell elongation and division during Streptomyces sporulation

Science.gov (United States)

Donczew, Magdalena; Mackiewicz, Paweł; Wróbel, Agnieszka; Flärdh, Klas; Zakrzewska-Czerwińska, Jolanta

2016-01-01

In unicellular bacteria, the ParA and ParB proteins segregate chromosomes and coordinate this process with cell division and chromosome replication. During sporulation of mycelial Streptomyces, ParA and ParB uniformly distribute multiple chromosomes along the filamentous sporogenic hyphal compartment, which then differentiates into a chain of unigenomic spores. However, chromosome segregation must be coordinated with cell elongation and multiple divisions. Here, we addressed the question of whether ParA and ParB are involved in the synchronization of cell-cycle processes during sporulation in Streptomyces. To answer this question, we used time-lapse microscopy, which allows the monitoring of growth and division of single sporogenic hyphae. We showed that sporogenic hyphae stop extending at the time of ParA accumulation and Z-ring formation. We demonstrated that both ParA and ParB affect the rate of hyphal extension. Additionally, we showed that ParA promotes the formation of massive nucleoprotein complexes by ParB. We also showed that FtsZ ring assembly is affected by the ParB protein and/or unsegregated DNA. Our results indicate the existence of a checkpoint between the extension and septation of sporogenic hyphae that involves the ParA and ParB proteins. PMID:27248800

Micro-dosing for early biokinetic studies in humans

International Nuclear Information System (INIS)

Stenstroem, K.; Sydoff, M.; Mattsson, S.

2010-01-01

Micro-dosing is a new concept in drug development that-if implemented in the pharmaceutical industry-would mean that new drugs can be tested earlier in humans than done today. The human micro-dosing concept-or 'Phase 0'-may offer improved candidate selection, reduced failure rates in the drug development line and a reduction in the use of laboratory animals in early drug development, factors which will help to speed up drug development and also reduce the costs. Micro-dosing utilises sub-pharmacological amounts of the substance to open opportunities for early studies in man. Three technologies are used for micro-dosing: accelerator mass spectrometry (AMS), positron emission tomography and liquid chromatography-tandem mass spectrometry. This paper focuses on the principle of AMS and discusses the current status of micro-dosing with AMS. (authors)

Targeted microbubbles for imaging tumor angiogenesis: assessment of whole-body biodistribution with dynamic micro-PET in mice

DEFF Research Database (Denmark)

Willmann, Jürgen K; Cheng, Zhen; Davis, Corrine

2008-01-01

To evaluate in vivo whole-body biodistribution of microbubbles (MBs) targeted to tumor angiogenesis-related vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) by using dynamic micro-positron emission tomography (PET) in living mice.......To evaluate in vivo whole-body biodistribution of microbubbles (MBs) targeted to tumor angiogenesis-related vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) by using dynamic micro-positron emission tomography (PET) in living mice....

Par Pond water balance

International Nuclear Information System (INIS)

Hiergesell, R.A.; Dixon, K.L.

1996-06-01

A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs

Report of radiological safety for a micro PET

International Nuclear Information System (INIS)

Gallegos M, R.; Ruiz T, C. G.; Martinez D, A.; Rodriguez V, M.

2010-09-01

Considering one of the guides emitted by the National Commission of Nuclear Security and Safeguards, was realized the report of radiological safety for a micro tomography by positrons emission that is part of Bimodal System of Images developed in their entirety for personnel of the Physics Institute of UNAM. With this system is sought to obtain tomography images of small animals using non destructive methods, such as computerized micro tomography and micro tomography by positrons emission. In this work each one of the report points is enumerated and only it is described, to big features on that consist, due to the great extension of each one of them. The report has two parts; the first is denominated -Of the installation and the Organization- and is given to know the interior and external characteristics of the installation, besides how and under which authority the activities will be executed inside the laboratory. The second part is called -of the Radiological Protection- and has for objective to describe the radiation sources that will be used, as well as the measures of radiological protection foreseen inside the laboratory. The most important part in the report consists on the description of the three radionuclides to use: 18 F, 11 C and 13 N, as well as the methods for the shielding calculation and for the estimate of the dose equivalent during the normal operation of the equipment. These methods were applied three times, because the calculation was made for each radionuclide. The results of these calculations show that: 1) it not is necessary to have a structural shielding, due to the activity sources very reduced, and 2) the dose limit per year (according to the ICRP-60) it will not be surpassed neither in the case of the occupationally exposed personnel, neither on the public in general. (Author

suPAR

DEFF Research Database (Denmark)

Hodges, Gethin W; Bang, Casper N; Wachtell, Kristian

2015-01-01

The fundamental role of inflammation in cardiovascular disease (CVD) has prompted interest in numerous biomarkers that detect subclinical levels of inflammation. Soluble urokinase plasminogen activator receptor (suPAR) is a novel biomarker that correlates significantly with cardiovascular events ...... comprehensive review of suPAR in CVD and explore its function and usefulness in predicting cardiovascular events....

Contrast Agents for Micro-Computed Tomography of Microdamage in Bone

Science.gov (United States)

2011-01-01

However, cracks in the enamel were readily detected by micro-CT both with and without the use of a con- trast agent (Fig. 2(b)) due to the relatively low x...ray attenua- tion of the fluid space in the crack compared to the enamel . Therefore, the main limitation of the difficulty distinguishing BaSO4 from...Roeder, 2011). Moreover, cracks in whole human molars were also imaged by contrast-enhanced micro-CT (Appendix 5, Landrigan et al., 2010). KEY

C9.A/14 steelwork joints de poutres par plaque frontale : assemblages par gousset

CERN Document Server

2015-01-01

Les Tables de résistances ultimes des assemblages boulonnés par plaque frontale et par gousset, complétées par une description des modèles de calcul et des exemples d’application, ont pour but de faciliter la tâche de l'ingénieur et du constructeur. Cette première partie C9.A/14 contient les chapitres suivants: - Joints de poutres par plaque frontale en acier S235 et S355 - Assemblages par gousset en acier S235 et S355 Les Tables contiennent des données relatives à la géométrie ainsi que les valeurs de calcul correspondantes des résistances ultimes des assemblages ; elles remplacent le chapitre « Assemblages par plaques frontales et boulons HR » des anciennes Tables C9.1 de 1983 / 2002. Le calcul de ces assemblages par plaque frontale est basé sur les hypothèses du modèle de la méthode des composants décrite dans la norme SN EN 1993-1-8. Les vérifications sont effectuées selon la norme SIA 263:2013. Les assemblages par gousset remplacent les assemblages par double cornière, (telle...

Evaluation of the macular architecture of patients operated on from macula-off rhegmatogenous retinal detachment using optical coherence tomography

International Nuclear Information System (INIS)

Ramos Lopez, Meisy; Obret Mendive, Isabel; Hernandez Silva, Juan Raul

2010-01-01

With the support of optical coherence tomography, to evaluate the macular condition of the patients operated on from rhegmatogenous retinal detachment, with detached macula, who underwent buckling surgery and pars plana vitrectomy

Investigation of a pre-clinical mandibular bone notch defect model in miniature pigs: clinical computed tomography, micro-computed tomography, and histological evaluation.

Science.gov (United States)

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.

The reliability of cone-beam computed tomography to assess bone density at dental implant recipient sites: a histomorphometric analysis by micro-CT.

Science.gov (United States)

González-García, Raúl; Monje, Florencio

2013-08-01

The aim of this study was to objectively assess the reliability of the cone-beam computed tomography (CBCT) as a tool to pre-operatively determine radiographic bone density (RBD) by the density values provided by the system, analyzing its relationship with histomorphometric bone density expressed as bone volumetric fraction (BV/TV) assessed by micro-CT of bone biopsies at the site of insertion of dental implants in the maxillary bones. Thirty-nine bone biopsies of the maxillary bones at the sites of 39 dental implants from 31 edentulous healthy patients were analyzed. The NobelGuide™ software was used for implant planning, which also allowed fabrication of individual stereolithographic surgical guides. The analysis of CBCT images allowed pre-operative determination of mean density values of implant recipient sites along the major axis of the planned implants (axial RBD). Stereolithographic surgical guides were used to guide implant insertion and also to extract cylindrical bone biopsies from the core of the exact implant site. Further analysis of several osseous micro-structural variables including BV/TV was performed by micro-CT of the extracted bone biopsies. Mean axial RBD was 478 ± 212 (range: 144-953). A statistically significant difference (P = 0.02) was observed among density values of the cortical bone of the upper maxilla and mandible. A high positive Pearson's correlation coefficient (r = 0.858, P micro-CT at the site of dental implants in the maxillary bones. Pre-operative estimation of density values by CBCT is a reliable tool to objectively determine bone density. © 2012 John Wiley & Sons A/S.

Micro-tomography based Geometry Modeling of Three-Dimensional Braided Composites

Science.gov (United States)

Fang, Guodong; Chen, Chenghua; Yuan, Shenggang; Meng, Songhe; Liang, Jun

2018-06-01

A tracking and recognizing algorithm is proposed to automatically generate irregular cross-sections and central path of braid yarn within the 3D braided composites by using sets of high resolution tomography images. Only the initial cross-sections of braid yarns in a tomography image after treatment are required to be calibrated manually as searching cross-section template. The virtual geometry of 3D braided composites including some detailed geometry information, such as the braid yarn squeezing deformation, braid yarn distortion and braid yarn path deviation etc., can be reconstructed. The reconstructed geometry model can reflect the change of braid configurations during solidification process. The geometry configurations and mechanical properties of the braided composites are analyzed by using the reconstructed geometry model.

Apical Root Canal Morphology of Mesial Roots of Mandibular First Molar Teeth with Vertucci Type II Configuration by Means of Micro-Computed Tomography.

Science.gov (United States)

Keleş, Ali; Keskin, Cangül

2017-03-01

The aim of this study was to assess the features of the apical root canal anatomy and its relation to the level at which 2 separate root canals merge in the mesial roots of the mandibular first molars with Vertucci type II canal configuration by using micro-computed tomography analysis. The anatomic features of the apical 3 mm of root canals in 83 mesial roots of mandibular first molar teeth were investigated by micro-computed tomography and software imaging according to the level at which 2 separate root canals merge. The most apical slice where a visible root canal was detectable was recorded as 0 level. The specimens from where 2 root canals rejoin at within 3 mm from the 0 level were then assigned to group 1 (n = 37), whereas the specimens from where root canals rejoin 3-9 mm from the 0 level were assigned to group 2 (n = 46). Data were presented by using descriptive statistics and Mann-Whitney U tests, with the significance level set at 5%. In all specimens the long oval type of cross-sectional shape increased from 50.9% at 1 mm to 80.5% at 3 mm. Group 1 presented significantly higher major diameter values compared with group 2 (P  .05) between groups. Group 2 displayed significantly higher roundness values than group 1 (P < .05). A long oval root cross section of apical root canal anatomy is more prevalent in roots for which 2 root canals merge within apical 3 mm of root canals. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography

International Nuclear Information System (INIS)

Haboub, Abdel; Nasiatka, James R.; MacDowell, Alastair A.; Bale, Hrishikesh A.; Cox, Brian N.; Marshall, David B.; Ritchie, Robert O.

2014-01-01

A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C

Comparative investigation of two-dimensional imaging methods and X-ray tomography in the characterization of microstructure

Energy Technology Data Exchange (ETDEWEB)

Bacaicoa, Inigo; Luetje, Martin [Kassel Univ. (Germany). Inst. of Materials Engineering, Quality and Reliability; Saelzer, Philipp [Kassel Univ. (Germany). Abt. Materialentwicklung und Verbundwerkstoffe; Umbach, Cristin [Kassel Univ. (Germany). Inst. for Structural Engineering; Brueckner-Foit, Angelika [Kassel Univ. (Germany). Inst. of Materials Engineering; Heim, Hans-Peter [Kassel Univ. (Germany). Plastics Engineering; Middendorf, Bernhard [Kassel Univ. (Germany). Dept. of Building Materials and Construction Chemistry

2017-11-01

The microstructural features of three different materials have been quantified by means of 2D image analysis and X-ray micro-computer tomography (CT) and the results were compared to determine the reliability of the 2D analysis in the material characterization. The 3D quantification of shrinkage pores and Fe-rich inclusions of an Al-Si-Cu alloy by X-ray tomography was compared with the statistical analysis of the 2D metallographic pictures and a significant difference in the results was found due to the complex morphology of shrinkage pores and Fe-rich particles. Furthermore, wood particles of a wood-plastic composite were measured by dynamic image analysis and X-ray tomography. Similar results were obtained for the maximum length of the particles, although the results of width differ considerably, which leads to a miscalculation of the particles aspect ratio. Finally, air voids of a foam concrete were investigated by the analysis of the 2D pictures in ImageJ and the results of the 2D circularity were compared with the values of the 3D elongation obtained by micro-computed tomography. The 3D analysis of the air voids in the foam concrete showed a more precise description of the morphology, although the 2D result are in good agreement with the results obtained by X-ray micro-tomography.

Comparative investigation of two-dimensional imaging methods and X-ray tomography in the characterization of microstructure

International Nuclear Information System (INIS)

Bacaicoa, Inigo; Luetje, Martin; Saelzer, Philipp; Umbach, Cristin; Brueckner-Foit, Angelika; Heim, Hans-Peter; Middendorf, Bernhard

2017-01-01

The microstructural features of three different materials have been quantified by means of 2D image analysis and X-ray micro-computer tomography (CT) and the results were compared to determine the reliability of the 2D analysis in the material characterization. The 3D quantification of shrinkage pores and Fe-rich inclusions of an Al-Si-Cu alloy by X-ray tomography was compared with the statistical analysis of the 2D metallographic pictures and a significant difference in the results was found due to the complex morphology of shrinkage pores and Fe-rich particles. Furthermore, wood particles of a wood-plastic composite were measured by dynamic image analysis and X-ray tomography. Similar results were obtained for the maximum length of the particles, although the results of width differ considerably, which leads to a miscalculation of the particles aspect ratio. Finally, air voids of a foam concrete were investigated by the analysis of the 2D pictures in ImageJ and the results of the 2D circularity were compared with the values of the 3D elongation obtained by micro-computed tomography. The 3D analysis of the air voids in the foam concrete showed a more precise description of the morphology, although the 2D result are in good agreement with the results obtained by X-ray micro-tomography.

Micro tomography prototype by positron emission. Spatial resolution and metabolic studies;Prototipo de microtomografo por emision de positrones. Resolucion espacial y estudios metabolicos

Energy Technology Data Exchange (ETDEWEB)

Alva S, H.; Murrieta, T.; Ruiz T, C.; Brandan, M. E.; Martinez D, A.; Rodriguez V, M., E-mail: halva@fisica.unam.m [UNAM, Instituto de Fisica, Circuito de la Investigacion Cientifica s/n, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

2010-07-01

During the past 4 years, the Medical Physics and Dosimetry Group at the Physics Institute, UNAM, has developed a positron emission tomography prototype for small-animal imaging (micro PET). The system is composed of pix elated, cerium-doped lutetium yttrium oxy orthosilicate scintillation crystal arrays coupled to position-sensitive photomultiplier tubes. Detector electronic signals are processed by nuclear instrumentation modules and are digitized by a multichannel data acquisition board. The tomographic reconstruction is performed by filtered backprojection from a set of distortion- and nonuniformity- corrected projections taken at different angles. In this work, the reconstructed spatial resolution was evaluated from the line spread function with a mean value of 2.36 +- 0.44 mm. In addition, the first metabolic studies of 30 g, healthy mice, injected with {sup 1}8{sup F} labeled fluorodeoxyglucose and sodium fluoride are reported. They display normal glucose uptake and skeletal structure, respectively. The micro PET can be a useful tool for radiation detector physics research and its applications in nuclear medicine. (Author)

Parálisis cerebral :

OpenAIRE

Cabrero Izquierdo, María del Carmen

2012-01-01

Se aborda el tema de la parálisis cerebral definiendo qué es, clasificando los tipos de parálisis dependiendo de la afectación y las características principales. Se explican algunos de sus tratamientos, se dan sistemas alternativos y/o aumentativos de comunicación para un alumno con PC (parálisis cerebral).

Terahertz Computed Tomography of NASA Thermal Protection System Materials

Science.gov (United States)

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.

Quantitative tomography of hydrogen precharged and uncharged Al-Zn-Mg-Cu alloy after tensile fracture

Energy Technology Data Exchange (ETDEWEB)

Gupta, C., E-mail: joy_gupta71@yahoo.co.in [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Toda, H.; Fujioka, T.; Kobayashi, M. [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Hoshino, H. [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Japan Synchrotron Radiation Institute, Sayo-Gun, Hyogo (Japan); Uesugi, K.; Takeuchi, A.; Suzuki, Y. [Japan Synchrotron Radiation Institute, Sayo-Gun, Hyogo (Japan)

2016-07-18

Quantitative tomography is carried out on datasets derived from tensile fracture sample of electrochemically precharged Al-Zn-Mg-Cu alloy in the underaged condition and its uncharged counterpart. It is shown that precharging which induces a transition of tensile fracture mode from ductile to brittle, results in a significant increase in micro-damage content in the regions near the fracture surfaces. Using quantitative tomography analysis based on spatial mapping of morphologically segmented micro-damage content of the datasets it is found that the precharged sample contains an inhomogenous distribution of micro-pores near grain boundaries. It is also shown that the spatial architecture of micro-pores in the dataset is not influenced by the plastic zone of the intergranular cracks lying along the grain boundaries. Contrastingly the micro-pores in the tomographic dataset of the uncharged sample are shown to be present near intermetallic particles. It is therefore rationalized that the spatial architecture of micro-pores in the datasets from uncharged sample originate from particle cracking during ductile fracture, and from the tendency for damage enhancement by the synergism of hydrogen exposure near grain boundaries and localization of deformation in the precharged sample dataset.

Painful spondylolysis or spondylolisthesis studied by radiography and single-photon emission computed tomography

International Nuclear Information System (INIS)

Collier, B.D.; Johnson, R.P.; Carrera, G.F.

1985-01-01

Planar bone scintigraphy (PBS) and single-photon emission computed tomography (SPECT) were compared in 19 adults with radiographic evidence of spondylolysis and/or spondylolisthesis. SPECT was more sensitive than PBS when used to identify symptomatic patients and sites of painful defects in the pars interarticularis. In addition, SPECT allowed more accurate localization than PBS. In 6 patients, spondylolysis or spondylolisthesis was unrealted to low back pain, and SPECT images of the posterior neural arch were normal. The authors conclude that when spondylolysis or spondylolisthesis is the cause of low back pain, pars defects are frequently heralded by increased scintigraphic activity which is best detected and localized by SPECT

Painful spondylolysis or spondylolisthesis studied by radiography and single-photon emission computed tomography

Energy Technology Data Exchange (ETDEWEB)

Collier, B.D.; Johnson, R.P.; Carrera, G.F.; Meyer, G.A.; Schwab, J.P.; Flatley, T.J.; Isitman, A.T.; Hellman, R.S.; Zielonka, J.S.; Knobel, J.

1985-01-01

Planar bone scintigraphy (PBS) and single-photon emission computed tomography (SPECT) were compared in 19 adults with radiographic evidence of spondylolysis and/or spondylolisthesis. SPECT was more sensitive than PBS when used to identify symptomatic patients and sites of painful defects in the pars interarticularis. In addition, SPECT allowed more accurate localization than PBS. In 6 patients, spondylolysis or spondylolisthesis was unrealted to low back pain, and SPECT images of the posterior neural arch were normal. The authors conclude that when spondylolysis or spondylolisthesis is the cause of low back pain, pars defects are frequently heralded by increased scintigraphic activity which is best detected and localized by SPECT.

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

Science.gov (United States)

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).

Determination of strain fields in porous shape memory alloys using micro-computed tomography

Science.gov (United States)

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.

;Study of secondary hydriding at high temperature in zirconium based nuclear fuel cladding tubes by coupling information from neutron radiography/tomography, electron probe micro analysis, micro elastic recoil detection analysis and laser induced breakdown spectroscopy microprobe

Science.gov (United States)

Brachet, Jean-Christophe; Hamon, Didier; Le Saux, Matthieu; Vandenberghe, Valérie; Toffolon-Masclet, Caroline; Rouesne, Elodie; Urvoy, Stéphane; Béchade, Jean-Luc; Raepsaet, Caroline; Lacour, Jean-Luc; Bayon, Guy; Ott, Frédéric

2017-05-01

This paper gives an overview of a multi-scale experimental study of the secondary hydriding phenomena that can occur in nuclear fuel cladding materials exposed to steam at high temperature (HT) after having burst (loss-of-coolant accident conditions). By coupling information from several facilities, including neutron radiography/tomography, electron probe micro analysis, micro elastic recoil detection analysis and micro laser induced breakdown spectroscopy, it was possible to map quantitatively, at different scales, the distribution of oxygen and hydrogen within M5™ clad segments having experienced ballooning and burst at HT followed by steam oxidation at 1100 and 1200 °C and final direct water quenching down to room temperature. The results were very reproducible and it was confirmed that internal oxidation and secondary hydriding at HT of a cladding after burst can lead to strong axial and azimuthal gradients of hydrogen and oxygen concentrations, reaching 3000-4000 wt ppm and 1.0-1.2 wt% respectively within the β phase layer for the investigated conditions. Consistent with thermodynamic and kinetics considerations, oxygen diffusion into the prior-β layer was enhanced in the regions highly enriched in hydrogen, where the α(O) phase layer is thinner and the prior-β layer thicker. Finally the induced post-quenching hardening of the prior-β layer was mainly related to the local oxygen enrichment. Hardening directly induced by hydrogen was much less significant.

Novel role for proteinase-activated receptor 2 (PAR2) in membrane trafficking of proteinase-activated receptor 4 (PAR4).

Science.gov (United States)

Cunningham, Margaret R; McIntosh, Kathryn A; Pediani, John D; Robben, Joris; Cooke, Alexandra E; Nilsson, Mary; Gould, Gwyn W; Mundell, Stuart; Milligan, Graeme; Plevin, Robin

2012-05-11

Proteinase-activated receptors 4 (PAR(4)) is a class A G protein-coupled receptor (GPCR) recognized through the ability of serine proteases such as thrombin and trypsin to mediate receptor activation. Due to the irreversible nature of activation, a fresh supply of receptor is required to be mobilized to the cell surface for responsiveness to agonist to be sustained. Unlike other PAR subtypes, the mechanisms regulating receptor trafficking of PAR(4) remain unknown. Here, we report novel features of the intracellular trafficking of PAR(4) to the plasma membrane. PAR(4) was poorly expressed at the plasma membrane and largely retained in the endoplasmic reticulum (ER) in a complex with the COPI protein subunit β-COP1. Analysis of the PAR(4) protein sequence identified an arginine-based (RXR) ER retention sequence located within intracellular loop-2 (R(183)AR → A(183)AA), mutation of which allowed efficient membrane delivery of PAR(4). Interestingly, co-expression with PAR(2) facilitated plasma membrane delivery of PAR(4), an effect produced through disruption of β-COP1 binding and facilitation of interaction with the chaperone protein 14-3-3ζ. Intermolecular FRET studies confirmed heterodimerization between PAR(2) and PAR(4). PAR(2) also enhanced glycosylation of PAR(4) and activation of PAR(4) signaling. Our results identify a novel regulatory role for PAR(2) in the anterograde traffic of PAR(4). PAR(2) was shown to both facilitate and abrogate protein interactions with PAR(4), impacting upon receptor localization and cell signal transduction. This work is likely to impact markedly upon the understanding of the receptor pharmacology of PAR(4) in normal physiology and disease.

Three-dimensional optical coherence micro-elastography of skeletal muscle tissue

OpenAIRE

Chin, Lixin; Kennedy, Brendan F.; Kennedy, Kelsey M.; Wijesinghe, Philip; Pinniger, Gavin J.; Terrill, Jessica R.; McLaughlin, Robert A.; Sampson, David D.

2014-01-01

In many muscle pathologies, impairment of skeletal muscle function is closely linked to changes in the mechanical properties of the muscle constituents. Optical coherence micro-elastography (OCME) uses optical coherence tomography (OCT) imaging of tissue under a quasi-static, compressive mechanical load to map variations in tissue mechanical properties on the micro-scale. We present the first study of OCME on skeletal muscle tissue. We show that this technique can resolve features of muscle t...

INTRASURGICAL MICROSCOPE-INTEGRATED SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY-ASSISTED MEMBRANE PEELING.

Science.gov (United States)

Falkner-Radler, Christiane I; Glittenberg, Carl; Gabriel, Max; Binder, Susanne

2015-10-01

To evaluate microscope-integrated intrasurgical spectral domain optical coherence tomography during macular surgery in a prospective monocenter study. Before pars plana vitrectomy and before, during, and after membrane peeling, 512 × 128 macular cube scans were performed using a Carl Zeiss Meditec Cirrus high-definition OCT system adapted to the optical pathway of a Zeiss OPMI VISU 200 surgical microscope and compared with retinal staining. The study included 51 patients with epiretinal membranes, with 8 of those having additional lamellar macular holes, 11 patients with vitreomacular traction, and 8 patients with full-thickness macular holes. Intraoperative spectral domain optical coherence tomography allowed performing membrane peeling without using retinal dyes in 40% of cases (28 of 70 patients). No residual membranes were found in 94.3% of patients (66 of 70 patients) in intrasurgical spectral domain optical coherence tomography and subsequent (re)staining. In patients with vitreomacular traction, intrasurgical spectral domain optical coherence tomography scans facilitated decisions on the need for an intraocular tamponade after membrane peeling. Intraoperative spectral domain optical coherence tomography was comparable with retinal dyes in confirming success after membrane peeling. However, the visualization of flat membranes was better after staining.

Optical coherence tomography imaging of chorioretinal folds associated with hypotony maculopathy following pars plana vitrectomy

Directory of Open Access Journals (Sweden)

Williams Jr BK

2015-09-01

Full Text Available Basil K Williams Jr, Jonathan S Chang, Harry W Flynn Jr Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA Abstract: Chorioretinal folds may occur as a consequence of hypotony and can be a cause of vision loss when associated with macular involvement. In this report, the spectral domain ocular coherence tomography imaging of three patients with chorioretinal folds before and after management are presented. The cases had unique presentations and each underwent different management approaches, but the results included improved visual acuities and lessened chorioretinal folds. Keywords: hypotony, chorioretinal folds, ocular coherence tomography

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

Science.gov (United States)

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

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

Science.gov (United States)

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-positron emission tomography for measuring sub-core scale single and multiphase transport parameters in porous media

Science.gov (United States)

Zahasky, Christopher; Benson, Sally M.

2018-05-01

Accurate descriptions of heterogeneity in porous media are important for understanding and modeling single phase (e.g. contaminant transport, saltwater intrusion) and multiphase (e.g. geologic carbon storage, enhanced oil recovery) transport problems. Application of medical imaging to experimentally quantify these processes has led to significant progress in material characterization and understanding fluid transport behavior at laboratory scales. While widely utilized in cancer diagnosis and management, cardiology, and neurology, positron emission tomography (PET) has had relatively limited applications in earth science. This study utilizes a small-bore micro-PET scanner to image and quantify the transport behavior of pulses of a conservative aqueous radiotracer injected during single and multiphase flow experiments in two heterogeneous Berea sandstone cores. The cores are discretized into axial-parallel streamtubes, and using the reconstructed micro-PET data, expressions are derived from spatial moment analysis for calculating sub-core tracer flux and pore water velocity. Using the flux and velocity measurements, it is possible to calculate porosity and saturation from volumetric flux balance, and calculate permeability and water relative permeability from Darcy's law. Second spatial moment analysis enables measurement of sub-core solute dispersion during both single phase and multiphase experiments. A numerical simulation model is developed to verify the assumptions of the streamtube dimension reduction technique. A variation of the reactor ratio is presented as a diagnostic metric to efficiently determine the validity of the streamtube approximation in core and column-scale experiments. This study introduces a new method to quantify sub-core permeability, relative permeability, and dispersion. These experimental and analytical methods provide a foundation for future work on experimental measurements of differences in transport behavior across scales.

Scout-view assisted interior micro-CT

International Nuclear Information System (INIS)

Sharma, Kriti Sen; Narayanan, Shree; Agah, Masoud; Holzner, Christian; Vasilescu, Dragoş M; Jin, Xin; Hoffman, Eric A; Yu, Hengyong; Wang, Ge

2013-01-01

Micro computed tomography (micro-CT) is a widely-used imaging technique. A challenge of micro-CT is to quantitatively reconstruct a sample larger than the field-of-view (FOV) of the detector. This scenario is characterized by truncated projections and associated image artifacts. However, for such truncated scans, a low resolution scout scan with an increased FOV is frequently acquired so as to position the sample properly. This study shows that the otherwise discarded scout scans can provide sufficient additional information to uniquely and stably reconstruct the interior region of interest. Two interior reconstruction methods are designed to utilize the multi-resolution data without significant computational overhead. While most previous studies used numerically truncated global projections as interior data, this study uses truly hybrid scans where global and interior scans were carried out at different resolutions. Additionally, owing to the lack of standard interior micro-CT phantoms, we designed and fabricated novel interior micro-CT phantoms for this study to provide means of validation for our algorithms. Finally, two characteristic samples from separate studies were scanned to show the effect of our reconstructions. The presented methods show significant improvements over existing reconstruction algorithms. (paper)

Validation of Micro-Meso Electrical Relations for Laminates with Varying Anisotropy

KAUST Repository

Selvakumaran, Lakshmi; Lubineau, Gilles

2015-01-01

For electrical impedance tomography (EIT) to be useful in monitoring transverse cracks in composites, it is imperative to establish the relation between conductivity and cracking density. Micro to meso scale homogenization has been developed

In-line phase contrast micro-CT reconstruction for biomedical specimens.

Science.gov (United States)

Fu, Jian; Tan, Renbo

2014-01-01

X-ray phase contrast micro computed tomography (micro-CT) can non-destructively provide the internal structure information of soft tissues and low atomic number materials. It has become an invaluable analysis tool for biomedical specimens. Here an in-line phase contrast micro-CT reconstruction technique is reported, which consists of a projection extraction method and the conventional filter back-projection (FBP) reconstruction algorithm. The projection extraction is implemented by applying the Fourier transform to the forward projections of in-line phase contrast micro-CT. This work comprises a numerical study of the method and its experimental verification using a biomedical specimen dataset measured at an X-ray tube source micro-CT setup. The numerical and experimental results demonstrate that the presented technique can improve the imaging contrast of biomedical specimens. It will be of interest for a wide range of in-line phase contrast micro-CT applications in medicine and biology.

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

Science.gov (United States)

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 Micro-CT analysis showed that the bone volume ratio and the trabecular number increased significantly (p 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.

3D tomography of cells in micro-channels

Science.gov (United States)

Quint, S.; Christ, A. F.; Guckenberger, A.; Himbert, S.; Kaestner, L.; Gekle, S.; Wagner, C.

2017-09-01

We combine confocal imaging, microfluidics, and image analysis to record 3D-images of cells in flow. This enables us to recover the full 3D representation of several hundred living cells per minute. Whereas 3D confocal imaging has thus far been limited to steady specimens, we overcome this restriction and present a method to access the 3D shape of moving objects. The key of our principle is a tilted arrangement of the micro-channel with respect to the focal plane of the microscope. This forces cells to traverse the focal plane in an inclined manner. As a consequence, individual layers of passing cells are recorded, which can then be assembled to obtain the volumetric representation. The full 3D information allows for a detailed comparison with theoretical and numerical predictions unfeasible with, e.g., 2D imaging. Our technique is exemplified by studying flowing red blood cells in a micro-channel reflecting the conditions prevailing in the microvasculature. We observe two very different types of shapes: "croissants" and "slippers." Additionally, we perform 3D numerical simulations of our experiment to confirm the observations. Since 3D confocal imaging of cells in flow has not yet been realized, we see high potential in the field of flow cytometry where cell classification thus far mostly relies on 1D scattering and fluorescence signals.

Par Pond vegetation status 1996

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1996-12-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995, and into the early spring and late summer of 1996. Communities similar to the pre-drawdown, Par Pond aquatic plant communities continue to become re-established. Emergent beds of maidencane, lotus, waterlily, watershield, and Pontederia are extensive and well developed. Measures of percent cover, width of beds, and estimates of area of coverage with satellite data indicate regrowth within two years of from 40 to 60% of levels prior to the draw down. Cattail occurrence continued to increase during the summer of 1996, especially in the former warm arm of Par Pond, but large beds common to Par Pond prior to the draw down still have not formed. Lotus has invaded and occupies many of the areas formerly dominated by cattail beds. To track the continued development of macrophytes in Par Pond, future surveys through the summer and early fall of 1997, along with the evaluation of satellite data to map the extent of the macrophyte beds of Par Pond, are planned

Preliminary optical coherence tomography investigation of the temporo-mandibular joint disc

Science.gov (United States)

Mărcăuteanu, Corina; Demjan, Enikö; Sinescu, Cosmin; Negrutiu, Meda; Motoc, Adrian; Lighezan, Rodica; Vasile, Liliana; Hughes, Mike; Bradu, Adrian; Dobre, George; Podoleanu, Adrian G.

2010-02-01

Aim and objectives. The morphology and position of the temporo-mandibular disc are key issues in the diagnosis and treatment of arthrogenous temporo-mandibular disorders. Magnetic resonance imaging and arthroscopy are used today to identify: flattening of the pars posterior of the disc, perforation and/or adhesions in the pars intermedia of the disc and disc displacements. The present study proposes the investigation of the temporo-mandibular joint disc by optical coherence tomography (OCT). Material and methods. 8 human temporo-mandibular joint discs were harvested from dead subjects, under 40 year of age, and conserved in formalin. They had a normal morphology, with a thicker pars posterior (2,6 mm on the average) and a thinner pars intermedia (1mm on the average). We investigated the disc samples using two different OCT systems: an en-face OCT (time domain (TD)-OCT) system, working at 1300 nm (C-scan and B-scan mode) and a spectral OCT system (a Fourier domain (FD)-OCT) system , working at 840 nm (B-scan mode). Results. The OCT investigation of the temporo-mandibular joint discs revealed a homogeneous microstructure. The longer wavelength of the TD-OCT offers a higher penetration depth (2,5 mm in air), which is important for the analysis of the pars posterior, while the FD-OCT is much faster. Conclusions: OCT is a promising imaging method for the microstructural characterization of the temporo-mandibular disc.

Neutron Tomography Application for Aircraft-parts and Root of Ginseng

Energy Technology Data Exchange (ETDEWEB)

Kim, Yi Kyung; Lee, Seung Wook; Sim, Chul Mu; Jeon, Jin Su; Kim, Tae Ju [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

2005-07-01

The neutron computerized tomography is considered to be a complementary tool to X-ray tomography in the sense that neutron interacts with atomic nucleus, otherwise X-ray interacts with an orbital electron of atom. The neutron tomography compared with X-ray tomography has a relatively short history. It is employed in stationary, as neutron sources are produced by the nuclear reactor. The full potential of the neutron tomography has yet to be investigated. Since, HANARO NRF was installed in 1995, the neutron radiography research group of KAERI has been developed the non-destructive testing methods by the computer tomography served for aerospace industry and agricultural industry. Concerning to NDT for aerospace, research was cooperated with Korean Air force. At the first stage, research was focused to find the micro-cracks based on internal passages inside aircraft parts and residual core of turbine blade. Concerning to NDT for agriculture, research was cooperated with the Agricultural Development and Technology Center. Research was focused to find the alive roots of Korean ginseng.

Budget impact from the incorporation of positron emission tomography ? computed tomography for staging lung cancers

OpenAIRE

Biz, Aline Navega; Caetano, Ros?ngela

2015-01-01

OBJECTIVE To estimate the budget impact from the incorporation of positron emission tomography (PET) in mediastinal and distant staging of non-small cell lung cancer.METHODS The estimates were calculated by the epidemiological method for years 2014 to 2018. Nation-wide data were used about the incidence; data on distribution of the disease´s prevalence and on the technologies’ accuracy were from the literature; data regarding involved costs were taken from a micro-costing study and from Brazi...

A comparison of micro-CT, microradiography and histomorphometry in bone research

NARCIS (Netherlands)

Gielkens, Pepijn F. M.; Schortinghuis, Jurjen; de Jong, Johan R.; Huysmans, Marie Charlotte D. N. J. M.; van Leeuwen, M. Barbara M.; Raghoebar, Gerry M.; Bos, Ruud R. M.; Stegenga, Boudewijn

Objective: Intraobserver reliability and agreement were determined for microradiography (MR), micro-computed tomography (mu CT) and histomorphometry (HM). These three modalities were compared for quantitative measurements of bone formation and graft modelling in rat mandibular defects and grafts.

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

Science.gov (United States)

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...

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

Science.gov (United States)

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.

Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography

Directory of Open Access Journals (Sweden)

Laila Gonzales Freire

2012-06-01

Full Text Available The aim of this study was to compare two methods of assessing apical transportation in curved canals after rotary instrumentation, namely, cross-sections and micro-computed tomography (µCT. Thirty mandibular molars were divided into two groups and prepared according to the requirements of each method. In G1 (cross-sections, teeth were embedded in resin blocks and sectioned at 2.0, 3.5, and 5.0 mm from the anatomic apex. Pre- and postoperative sections were photographed and analyzed. In G2 (µCT, teeth were embedded in a rubber-base impression material and scanned before and after instrumentation. Mesiobuccal canals were instrumented with the Twisted File (TF system (SybronEndo, Orange, USA, and mesiolingual canals, with the EndoSequence (ES system (Brasseler, Savannah, USA. Images were reconstructed, and sections corresponding to distances 2.0, 3.5, and 5.0 mm from the anatomic apex were selected for comparison. Data were analyzed using Mann-Whitney's test at a 5% significance level. The TF and ES instruments produced little deviation from the root canal center, with no statistical difference between them (P > 0.05. The canal transportation results were significantly lower (0.056 mm in G2 than in G1 (0.089 mm (p = 0.0012. The µCT method was superior to the cross-section method, especially in view of its ability to preserve specimens and provide results that are more closely related to clinical situations.

Extraction of the 3D local orientation of myocytes in human cardiac tissue using X-ray phase-contrast micro-tomography and multi-scale analysis.

Science.gov (United States)

Varray, François; Mirea, Iulia; Langer, Max; Peyrin, Françoise; Fanton, Laurent; Magnin, Isabelle E

2017-05-01

This paper presents a methodology to access the 3D local myocyte arrangements in fresh human post-mortem heart samples. We investigated the cardiac micro-structure at a high and isotropic resolution of 3.5 µm in three dimensions using X-ray phase micro-tomography at the European Synchrotron Radiation Facility. We then processed the reconstructed volumes to extract the 3D local orientation of the myocytes using a multi-scale approach with no segmentation. We created a simplified 3D model of tissue sample made of simulated myocytes with known size and orientations, to evaluate our orientation extraction method. Afterwards, we applied it to 2D histological cuts and to eight 3D left ventricular (LV) cardiac tissue samples. Then, the variation of the helix angles, from the endocardium to the epicardium, was computed at several spatial resolutions ranging from 3.6 3  mm 3 to 112 3  µm 3 . We measure an increased range of 20° to 30° from the coarsest resolution level to the finest level in the experimental samples. This result is in line with the higher values measured from histology. The displayed tractography demonstrates a rather smooth evolution of the transmural helix angle in six LV samples and a sudden discontinuity of the helix angle in two septum samples. These measurements bring a new vision of the human heart architecture from macro- to micro-scale. Copyright © 2017 Elsevier B.V. All rights reserved.

Stimulation de la capacité d'innovation des micro, petites et ...

International Development Research Centre (IDRC) Digital Library (Canada)

Stimulation de la capacité d'innovation des micro, petites et moyennes entreprises d'Asie par le truchement d'intermédiaires ... En plus d'études de cas comparatives menées en Chine et en Thaïlande, des bourses de recherche menant à la maîtrise ou au doctorat seront octroyées à de jeunes professeurs ainsi qu'à des ...

Use of micro computed-tomography and 3D printing for reverse engineering of mouse embryo nasal capsule

International Nuclear Information System (INIS)

Tesařová, M.; Zikmund, T.; Kaiser, J.; Kaucká, M.; Adameyko, I.; Jaroš, J.; Paloušek, D.; Škaroupka, D.

2016-01-01

Imaging of increasingly complex cartilage in vertebrate embryos is one of the key tasks of developmental biology. This is especially important to study shape-organizing processes during initial skeletal formation and growth. Advanced imaging techniques that are reflecting biological needs give a powerful impulse to push the boundaries of biological visualization. Recently, techniques for contrasting tissues and organs have improved considerably, extending traditional 2D imaging approaches to 3D . X-ray micro computed tomography (μCT), which allows 3D imaging of biological objects including their internal structures with a resolution in the micrometer range, in combination with contrasting techniques seems to be the most suitable approach for non-destructive imaging of embryonic developing cartilage. Despite there are many software-based ways for visualization of 3D data sets, having a real solid model of the studied object might give novel opportunities to fully understand the shape-organizing processes in the developing body. In this feasibility study we demonstrated the full procedure of creating a real 3D object of mouse embryo nasal capsule, i.e. the staining, the μCT scanning combined by the advanced data processing and the 3D printing

Ductile damage in aluminium alloy thin sheets: Correlation between micro-tomography observations and mechanical modeling

International Nuclear Information System (INIS)

Thuillier, S.; Maire, E.; Brunet, M.

2012-01-01

This work deals with the characterization of ductile damage in an aluminium alloy AA6016-T4 by X-ray micro-tomography, as a function of anisotropy and triaxiality. Interrupted tensile tests on notched samples with three different geometries were performed and the void volume fraction was measured for different strain values, up to rupture. It was shown that void volume fraction evolution with the strain is rather similar at 0° and 90° to RD but at 45° to RD it shows a more rapid evolution. Moreover, for the same strain level, a higher void volume fraction was recorded for a higher triaxiality ratio. Whatever the orientation and the stress triaxiality ratio, void volume fraction values range from 5×10 −4 up to 0.04. A numerical model based on Gurson–Tvergaard–Needleman constitutive equations was used to simulate the different tests. Hardening of the material was identified from macroscopic tensile test nucleation material parameters were identified by a direct method from void volume fraction evolution. It can be seen that the influence of triaxiality on void volume fraction is underestimated, though void growth is nicely predicted for the highest triaxiality ratio, for strains below 0.5. The load level was correctly predicted, except for high strain, where coalescence seems necessary to be taken into account.

Comparison of the release of microRNAs and extracellular vesicles from platelets in response to different agonists.

Science.gov (United States)

Ambrose, Ashley R; Alsahli, Mohammed A; Kurmani, Sameer A; Goodall, Alison H

2018-07-01

On activation platelets release microRNAs and extracellular vesicles (EV) into circulation. The release of EV from platelets has been shown to be dependent on the agonist; in this study, we investigated whether the microRNA profile or EV released from platelets was also agonist specific. Washed platelets from healthy subjects were maximally stimulated with agonists specific for the receptors for collagen (Glycoprotein VI (GPVI)), thrombin (PAR1/PAR4), or ADP (P2Y1/P2Y12) with/without inhibiting secondary mediators, using aspirin to block cyclooxygenase-1 and apyrase to remove ADP. The released microRNAs were profiled using TaqMan microRNA microarray cards. Platelet-derived EV (pdEV) were characterized by size (Nanoparticle Tracking Analysis, NTA), for procoagulant activity (Annexin-V binding and support of thrombin generation), and for the EV markers CD63 and HSP70. Platelet activation triggered the release of 57-79 different microRNAs, dependent upon agonist, with a core of 46 microRNAs observed with all agonists. There was a high level of correlation between agonists (r 2  > 0.98; p  0.98; p < 0.0001). The 46 microRNAs seen in all samples are predicted to have significant effects on the translation of proteins involved in endocytosis, cell cycle control, and differentiation. MiR-223-3p was the most abundant in all samples and has previously been implicated in myeloid lineage development and demonstrated to have anti-inflammatory effects. Stimulation through GPVI produced a pdEV population with significantly more procoagulant activity than the other agonists. Apyrase significantly reduced microRNA and pdEV release, while aspirin had little effect. These data suggest that all tested agonists trigger the release of a similar microRNA profile while the procoagulant activity of the pdEV was agonist dependent. ADP was shown to play an important role in the release of both microRNAs and pdEV.

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

Science.gov (United States)

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.

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

Directory of Open Access Journals (Sweden)

Pooi Ling Mok

2017-02-01

Full Text Available 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.

Impact load-induced micro-structural damage and micro-structure associated mechanical response of concrete made with different surface roughness and porosity aggregates

International Nuclear Information System (INIS)

Erdem, Savaş; Dawson, Andrew Robert; Thom, Nicholas Howard

2012-01-01

The relationship between the nature of micro damage under impact loading and changes in mechanical behavior associated with different microstructures is studied for concretes made with two different coarse aggregates having significant differences mainly in roughness and porosity — sintered fly ash and uncrushed gravel. A range of techniques including X-ray diffraction, digital image analysis, mercury porosimetry, X-ray computed tomography, laser surface profilometry and scanning electron microscopy were used to characterize the aggregates and micro-structures. The concrete prepared with lightweight aggregates was stronger in compression than the gravel aggregate concrete due to enhanced hydration as a result of internal curing. In the lightweight concrete, it was deduced that an inhomogeneous micro-structure led to strain incompatibilities and consequent localized stress concentrations in the mix, leading to accelerated failure. The pore structure, compressibility, and surface texture of the aggregates are of paramount importance for the micro-cracking growth.

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

Science.gov (United States)

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 (pperiodontal 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.

Morphological Characterisation of Unstained and Intact Tissue Micro-architecture by X-ray Computed Micro- and Nano-Tomography

Science.gov (United States)

Walton, Lucy A.; Bradley, Robert S.; Withers, Philip J.; Newton, Victoria L.; Watson, Rachel E. B.; Austin, Clare; Sherratt, Michael J.

2015-05-01

Characterisation and quantification of tissue structures is limited by sectioning-induced artefacts and by the difficulties of visualising and segmenting 3D volumes. Here we demonstrate that, even in the absence of X-ray contrast agents, X-ray computed microtomography (microCT) and nanotomography (nanoCT) can circumvent these problems by rapidly resolving compositionally discrete 3D tissue regions (such as the collagen-rich adventitia and elastin-rich lamellae in intact rat arteries) which in turn can be segmented due to their different X-ray opacities and morphologies. We then establish, using X-ray tomograms of both unpressurised and pressurised arteries that intra-luminal pressure not only increases lumen cross-sectional area and straightens medial elastic lamellae but also induces profound remodelling of the adventitial layer. Finally we apply microCT to another human organ (skin) to visualise the cell-rich epidermis and extracellular matrix-rich dermis and to show that conventional histological and immunohistochemical staining protocols are compatible with prior X-ray exposure. As a consequence we suggest that microCT could be combined with optical microscopy to characterise the 3D structure and composition of archival paraffin embedded biological materials and of mechanically stressed dynamic tissues such as the heart, lungs and tendons.

Auscultation of concrete hydraulic dams by sonic tomography; Auscultation des structures hydrauliques en beton par tomographie sonique

Energy Technology Data Exchange (ETDEWEB)

Kharrat, Y.; Rhazi, J.; Ballivy, G. [Sherbrooke Univ., PQ (Canada). Dept. de Genie Civil; Cote, P. [Centre de Nantes, Bouguenais (France)

1995-12-31

Sonic tomography, a new nondestructive testing method, was described to document the aging and internal degradation of concrete structures. The method is based on the transmission of sonic waves through concrete structures. New tomographic methodology similar to that used in medical or geophysical imaging was applied to existing sonic auscultation techniques used in civil engineering. In the process the speed of propagation of sonic waves in structures is measured with arrays of detectors. Fissures or zones of degradation can be spatially localized and an internal image of the structure can be constructed. Case studies of two hydraulic dams, one from France, the other in Quebec were presented as illustrations. . The theory and experimental procedures involved were described. 16 refs., 1 tab., 12 figs.

Contrast Agents for Micro-Computed Tomography of Microdamage in Bone

National Research Council Canada - National Science Library

Roeder, Ryan K

2008-01-01

...) and contrast agents with higher x-ray attenuation than bone. The ability to detect the presence and to a limited extent the morphology of microdamage in cortical and trabecular bone using micro-CT was demonstrated using a barium sulfate (BaSO4) stain...

Possible Radiation-Induced Damage to the Molecular Structure of Wooden Artifacts Due to Micro-Computed Tomography, Handheld X-Ray Fluorescence, and X-Ray Photoelectron Spectroscopic Techniques

Directory of Open Access Journals (Sweden)

Madalena Kozachuk

2016-05-01

Full Text Available This study was undertaken to ascertain whether radiation produced by X-ray photoelectron spectroscopy (XPS, micro-computed tomography (μCT and/or portable handheld X-ray fluorescence (XRF equipment might damage wood artifacts during analysis. Changes at the molecular level were monitored by Fourier transform infrared (FTIR analysis. No significant changes in FTIR spectra were observed as a result of μCT or handheld XRF analysis. No substantial changes in the collected FTIR spectra were observed when XPS analytical times on the order of minutes were used. However, XPS analysis collected over tens of hours did produce significant changes in the FTIR spectra.

Evaluating tooth restorations: micro-computed tomography in practical training for students in dentistry

Science.gov (United States)

Deyhle, Hans; Schmidli, Fredy; Krastl, Gabriel; Müller, Bert

2010-09-01

Direct composite fillings belong to widespread tooth restoration techniques in dental medicine. The procedure consists of successive steps, which include etching of the prepared tooth surface, bonding and placement of composite in incrementally built up layers. Durability and lifespan of the composite inlays strongly depend on the accurate completion of the individual steps to be also realized by students in dental medicine. Improper handling or nonconformity in the bonding procedure often lead to air enclosures (bubbles) as well as to significant gaps between the composite layers or at the margins of the restoration. Traditionally one analyzes the quality of the restoration cutting the tooth in an arbitrarily selected plane and inspecting this plane by conventional optical microscopy. Although the precision of this established method is satisfactory, it is restricted to the selected two-dimensional plane. Rather simple micro computed tomography (μCT) systems, such as SkyScan 1174™, allows for the non-destructive three-dimensional imaging of restored teeth ex vivo and virtually cutting the tomographic data in any desired direction, offering a powerful tool for inspection of the restored tooth with micrometer resolution before cutting and thus also to select a two-dimensional plane with potential defects. In order to study the influence of the individual steps on the resulted tooth restoration, direct composite fillings were placed in mod cavities of extracted teeth. After etching, an adhesive was applied in half of the specimens. From the tomographic datasets, it becomes clear that gaps occur more frequently when bonding is omitted. The visualization of air enclosures offers to determine the probability to find a micrometer-sized defect using an arbitrarily selected cutting plane for inspection.

Automatic method for estimation of in situ effective contact angle from X-ray micro tomography images of two-phase flow in porous media.

Science.gov (United States)

Scanziani, Alessio; Singh, Kamaljit; Blunt, Martin J; Guadagnini, Alberto

2017-06-15

Multiphase flow in porous media is strongly influenced by the wettability of the system, which affects the arrangement of the interfaces of different phases residing in the pores. We present a method for estimating the effective contact angle, which quantifies the wettability and controls the local capillary pressure within the complex pore space of natural rock samples, based on the physical constraint of constant curvature of the interface between two fluids. This algorithm is able to extract a large number of measurements from a single rock core, resulting in a characteristic distribution of effective in situ contact angle for the system, that is modelled as a truncated Gaussian probability density distribution. The method is first validated on synthetic images, where the exact angle is known analytically; then the results obtained from measurements within the pore space of rock samples imaged at a resolution of a few microns are compared to direct manual assessment. Finally the method is applied to X-ray micro computed tomography (micro-CT) scans of two Ketton cores after waterflooding, that display water-wet and mixed-wet behaviour. The resulting distribution of in situ contact angles is characterized in terms of a mixture of truncated Gaussian densities. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Imaging of metastatic lymph nodes by X-ray phase-contrast micro-tomography.

Directory of Open Access Journals (Sweden)

Torben Haugaard Jensen

Full Text Available Invasive cancer causes a change in density in the affected tissue, which can be visualized by x-ray phase-contrast tomography. However, the diagnostic value of this method has so far not been investigated in detail. Therefore, the purpose of this study was, in a blinded manner, to investigate whether malignancy could be revealed by non-invasive x-ray phase-contrast tomography in lymph nodes from breast cancer patients. Seventeen formalin-fixed paraffin-embedded lymph nodes from 10 female patients (age range 37-83 years diagnosed with invasive ductal carcinomas were analyzed by X-ray phase-contrast tomography. Ten lymph nodes had metastatic deposits and 7 were benign. The phase-contrast images were analyzed according to standards for conventional CT images looking for characteristics usually only visible by pathological examinations. Histopathology was used as reference. The result of this study was that the diagnostic sensitivity of the image analysis for detecting malignancy was 100% and the specificity was 87%. The positive predictive value was 91% for detecting malignancy and the negative predictive value was 100%. We conclude that x-ray phase-contrast imaging can accurately detect density variations to obtain information regarding lymph node involvement previously inaccessible with standard absorption x-ray imaging.

Resolution, sensitivity, and in vivo application of high-resolution computed tomography for titanium-coated polymethyl methacrylate (PMMA) dental implants

NARCIS (Netherlands)

Cuijpers, V.M.J.I.; Jaroszewicz, J.; Anil, S.; Al Farraj Aldosari, A.; Walboomers, X.F.; Jansen, J.A.

2014-01-01

OBJECTIVES: The aims of this study were (i) to determine the spatial resolution and sensitivity of micro- versus nano-computed tomography (CT) techniques and (ii) to validate micro- versus nano-CT in a dog dental implant model, comparative to histological analysis. MATERIAL AND METHODS: To determine

Protease-activated receptor (PAR)-2 is required for PAR-1 signalling in pulmonary fibrosis

NARCIS (Netherlands)

Lin, Cong; von der Thüsen, Jan; Daalhuisen, Joost; ten Brink, Marieke; Crestani, Bruno; van der Poll, Tom; Borensztajn, Keren; Spek, C. Arnold

2015-01-01

Idiopathic pulmonary fibrosis is the most devastating diffuse fibrosing lung disease of unknown aetiology. Compelling evidence suggests that both protease-activated receptor (PAR)-1 and PAR-2 participate in the development of pulmonary fibrosis. Previous studies have shown that bleomycin-induced

Agreement and precision of periprosthetic bone density measurements in micro-CT, single and dual energy CT.

Science.gov (United States)

Mussmann, Bo; Overgaard, Søren; Torfing, Trine; Traise, Peter; Gerke, Oke; Andersen, Poul Erik

2017-07-01

The objective of this study was to test the precision and agreement between bone mineral density measurements performed in micro CT, single and dual energy computed tomography, to determine how the keV level influences density measurements and to assess the usefulness of quantitative dual energy computed tomography as a research tool for longitudinal studies aiming to measure bone loss adjacent to total hip replacements. Samples from 10 fresh-frozen porcine femoral heads were placed in a Perspex phantom and computed tomography was performed with two acquisition modes. Bone mineral density was calculated and compared with measurements derived from micro CT. Repeated scans and dual measurements were performed in order to measure between- and within-scan precision. Mean density difference between micro CT and single energy computed tomography was 72 mg HA/cm 3 . For dual energy CT, the mean difference at 100 keV was 128 mg HA/cm 3 while the mean difference at 110-140 keV ranged from -84 to -67 mg HA/cm 3 compared with micro CT. Rescanning the samples resulted in a non-significant overall between-scan difference of 13 mg HA/cm 3 . Bland-Altman limits of agreement were wide and intraclass correlation coefficients ranged from 0.29 to 0.72, while 95% confidence intervals covered almost the full possible range. Repeating the density measurements for within-scan precision resulted in ICCs >0.99 and narrow limits of agreement. Single and dual energy quantitative CT showed excellent within-scan precision, but poor between-scan precision. No significant density differences were found in dual energy quantitative CT at keV-levels above 110 keV. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1470-1477, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Impaired bone formation in ovariectomized mice reduces implant integration as indicated by longitudinal in vivo micro-computed tomography.

Science.gov (United States)

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.

Directory of Open Access Journals (Sweden)

Zihui Li

Full Text Available 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 (remodeling, 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 (remodeling 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.

Positron emission tomography in the management of cervix cancer patients; Tomographie par emission de positons dans la prise en charge des cancers du col de l'uterus

Energy Technology Data Exchange (ETDEWEB)

Bonardel, G.; Gontier, E.; Soret, M.; Dechaud, C.; Fayolle, M.; Foehrenbach, H. [Hopital d' Instruction des Armees du Val-de-Grace, Service de Medecine Nucleaire, 75 - Paris (France); Chargari, C.; Bauduceau, O. [Hopital d' Instruction des Armees du Val-de-Grace, Service de Radiotherapie, 75 - Paris (France)

2009-10-15

Since its introduction in clinical practice in the 1990 s, positron emission tomography (PET), usually with {sup 18}F-fluoro-2-deoxy-D-glucose ({sup 18}F-F.D.G.), has become an important imaging modality in patients with cancer. For cervix carcinoma, F.D.G.-PET is significantly more accurate than computed tomography (CT) and is recommended for loco-regional lymph node and extra pelvic staging. The metabolic dimension of the technique provides additional prognostic information. Ongoing studies now concentrate on more advanced clinical applications, such as the planning of radiotherapy, the response evaluation after the induction of therapy, the early detection of recurrence. Technical innovations, such as PET cameras with better spatial resolution and hybrid positron emission tomography/computed tomography (PET-CT), available now on the whole territory, provide both anatomic and metabolic information in the same procedure. From the point of view of biological metabolism, new radiopharmaceutical probes are being developed. Those hold promise for future refinements in this field. This article reviews the current applications of F.D.G.-PET in patients with cervix cancer. (authors)

Vapor flux and recrystallization during dry snow metamorphism under a steady temperature gradient as observed by time-lapse micro-tomography

Directory of Open Access Journals (Sweden)

B. R. Pinzer

2012-10-01

Full Text Available Dry snow metamorphism under an external temperature gradient is the most common type of recrystallization of snow on the ground. The changes in snow microstructure modify the physical properties of snow, and therefore an understanding of this process is essential for many disciplines, from modeling the effects of snow on climate to assessing avalanche risk. We directly imaged the microstructural changes in snow during temperature gradient metamorphism (TGM under a constant gradient of 50 K m⁻¹, using in situ time-lapse X-ray micro-tomography. This novel and non-destructive technique directly reveals the amount of ice that sublimates and is deposited during metamorphism, in addition to the exact locations of these phase changes. We calculated the average time that an ice volume stayed in place before it sublimated and found a characteristic residence time of 2–3 days. This means that most of the ice changes its phase from solid to vapor and back many times in a seasonal snowpack where similar temperature conditions can be found. Consistent with such a short timescale, we observed a mass turnover of up to 60% of the total ice mass per day. The concept of hand-to-hand transport for the water vapor flux describes the observed changes very well. However, we did not find evidence for a macroscopic vapor diffusion enhancement. The picture of {temperature gradient metamorphism} produced by directly observing the changing microstructure sheds light on the micro-physical processes and could help to improve models that predict the physical properties of snow.

Dose fractionation in synchrotron radiation x-ray phase micro-tomography

International Nuclear Information System (INIS)

Frachon, Thibaut; Weber, Loriane; Hesse, Bernhard; Rit, Simon; Dong, Pei; Olivier, Cecile; Peyrin, Françoise; Langer, Max

2015-01-01

Phase sensitive x-ray imaging expands the applicability of standard attenuation based techniques by offering several orders of magnitude of increase in sensitivity. Due to the short wavelength, x-ray phase is not directly measurable, but has to be put in evidence by the use of phase contrast techniques. The phase can then be reconstructed from one or several phase contrast images. In this study, we consider synchrotron x-ray phase micro-computed tomography (μCT) based on free space propagation for heterogeneous and strongly absorbing objects. This technique generally relies on acquiring several scans of the sample at different detector distances. It is also generally believed that multi-distance phase μCT needs a higher dose input than single distance phase μCT. The purpose of this work is to study the impact of different means of dose fractionation on the reconstructed image quality. We define different acquistion schemes in multi-distance in-line phase μCT. Previously, the exposure time at each sample-to-detector distance was usually kept the same. Here, we let not only the number of distances vary but also the fraction of exposure time at each distance, the total exposure time being kept constant. Phase retrieval is performed with the mixed approach algorithm. The reconstructed μCT images are compared in terms of accuracy, precision and resolution. In addition, we also compare the result of dose fractionated multi distance phase μCT to single distance phase μCT using the same total radiation dose. In the multi-distance approach, we find that using different exposure times on each distance improves the image quality in the reconstructed image. Further, we show that, despite having the same total dose delivery, the multi distance imaging method gives better image quality than the single distance method, at the cost of an additional overhead from camera displacements and reference images. We show that by optimizing the acquistion parameters in terms of

Micro-CT of Carotid Arteries: A Tool for Experimental Studies

International Nuclear Information System (INIS)

Mohr, Andreas; Wenke, Ruediger; Roemer, Frank W.; Lynch, John A.; Gatzka, Christian; Priebe, Markus; Guermazi, Ali; Grigorian, Mikayel; Heller, Martin; Mueller-Huelsbeck, Stefan

2004-01-01

Micro-computed tomography (micro-CT) is a high-resolution, nondestructive tool for two- and three-dimensional imaging and quantification. The ability of this technique to assess atherosclerosis of the carotid artery was evaluated in three human cadaver samples based on the original axial acquisitions, multiplanar reconstructions and volume rendering techniques. Quantitative analysis included the calculation of: (1) the original lumen perimeter, original lumen area, plaque area, residual lumen area, calcified area and gross sectional area reduction of the vascular lumen from two-dimensional slices; (2) the total tissue volume, soft tissue volume and calcified tissue volume from the three-dimensional data set. This preliminary study demonstrates the potential of micro-CT as a supplementary method for the two- and three-dimensional ex vivo evaluation of carotid atherosclerosis

Evaluation of Collateral Source Characteristics With 3-Dimensional Analysis Using Micro-X-Ray Computed Tomography.

Science.gov (United States)

Arima, Yuichiro; Hokimoto, Seiji; Tabata, Noriaki; Nakagawa, Osamu; Oshima, Asahi; Matsumoto, Yosuke; Sato, Takahiro; Mukunoki, Toshifumi; Otani, Jun; Ishii, Masanobu; Uchikawa, Michie; Yamamoto, Eiichiro; Izumiya, Yasuhiro; Kaikita, Koichi; Ogawa, Hisao; Nishiyama, Koichi; Tsujita, Kenichi

2018-03-23

Collateral arteries provide an alternative blood supply and protect tissues from ischemic damage in patients with peripheral artery disease. However, the mechanism of collateral artery development is difficult to validate. Collateral arteries were visualized using micro-x-ray computed tomography. Developmental characteristics were assessed using confocal microscopy. We conducted a single-center, retrospective, observational study and assessed the dilatation of collateral arteries on ischemic sides. We quantified the vascular volume in both ischemic and nonischemic legs. A prominent increase in vascular volume was observed in the ischemic leg using a murine hind-limb ischemia model. We also performed qualitative assessment and confirmed that the inferior gluteal artery functioned as a major collateral source. Serial analysis of murine hind-limb vessel development revealed that the inferior gluteal artery was a remnant of the ischial artery, which emerged as a representative vessel on the dorsal side during hind-limb organogenesis. We retrospectively analyzed consecutive patients who were admitted for the diagnosis or treatment of peripheral artery disease. The diameter of the inferior gluteal artery on the ischemic side showed significant dilatation compared with that on the nonischemic side. Our findings indicate that an embryonic remnant artery can become a collateral source under ischemic conditions. Flow enhancement in the inferior gluteal artery might become a novel therapeutic approach for patients with peripheral artery disease. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Evaluation of ambient radiation levels in positron emission tomography/computed tomography in microPET/CT laboratory

International Nuclear Information System (INIS)

Sarmento, Daniele Martins

2016-01-01

Micro PET/CT scanner is an essential tool generally used for small animal molecular imaging. Fluorine-18-labeled fluorodeoxyglucose is the most widely used radioisotope in this technique. The present study aimed to evaluate the radiation levels in a micro PET/CT research laboratory of the Radiopharmacy Center at IPEN-CNEN / SP, in order to accomplish both national standards and international recommendations. The radioprotection team has classified the laboratory as supervised area; even this laboratory does not require the adoption of specific measures for protection and safety, should be done regular re-evaluation of the conditions of occupational exposures. Workplace monitoring and individual control assessment were carried out to ensure the radiological protection of all workers directly involved in handling the scanner. Initially, there was conducted a radiometric survey, as well as measurements of the external radiation level in the workplace and its surroundings. To achieve this goal, there were placed nine thermoluminescent dosimeters of CaSO 4 :Dy in preselected locations. Monthly evaluations of the occupationally exposed individuals were carried out through the use of TL dosimeters, ported in the workers' chest. Moreover, whole body measurements were performed every six months. The study period was about two-years which started in April 2014. All tests to evaluate micro PET/CT performance were based on the standard protocol of the equipment in accordance with the standard developed by the Animal PET Standard Task Force. Present study's results demonstrated that the ambient radiation levels (ambient and effective estimated radiation dose), as well as the effective shielding equipment are both adequate. This study emphasizes that it is essential to strictly follow the principles of radioprotection in workplace, whenever researches involve radioactive unsealed sources. (author)

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Assessment of residual coronal tooth structure postendodontic cavity preparation using digital dental impressions and micro-computed tomography.

Science.gov (United States)

Al-Nuaimi, Nassr; Patel, Shanon; Foschi, Federico; Mannocci, Francesco; Austin, Rupert S

To evaluate the in vitro accuracy of digital impressions for three-dimensional (3D) volumetric measurement of residual coronal tooth structure postendodontic cavity preparation, with reference to micro-computed tomography (μCT). Quantification of the accuracy and precision of the intraoral digital scanner (3M True Definition Scanner - IOS) was performed using a metrology gauge block and a profilometric calibration model. Thirty-four human extracted molars with endodontic access cavities were scanned using both intraoral scanning (test scanner) in high-resolution mode, and µCT (reference scanner: GE Locus SP μCT scanner) in high- (HiResCT) and low- (LoResCT) resolution modes. Comparisons of volumetric accuracy and 3D profilometric deviations were performed using surface metrology software. One-way repeated measures analysis of variance (ANOVA), in combination with the Bonferroni post hoc test, was implemented to compare the differences in volume measurements between scanning methods. Digital scanning revealed smaller volume measurements by 1.36% and 0.68% compared to HiResCT and LoResCT, respectively. There was a statistically significant difference in the volumetric measurements obtained from the IOS scanner and both HiResCT and LoResCT scans (P digital scanner was able to reliably measure the extra- and intracoronal aspect of the endodontically accessed tooth.

Trabecular bone structural parameters evaluated using dental cone-beam computed tomography: cellular synthetic bones.

Science.gov (United States)

Ho, Jung-Ting; Wu, Jay; Huang, Heng-Li; Chen, Michael Y c; Fuh, Lih-Jyh; Hsu, Jui-Ting

2013-11-09

This study compared the adequacy of dental cone beam computed tomography (CBCT) and micro computed tomography (micro-CT) in evaluating the structural parameters of trabecular bones. The cellular synthetic bones in 4 density groups (Groups 1-4: 0.12, 0.16, 0.20, and 0.32 g/cm3) were used in this study. Each group comprised 8 experimental specimens that were approximately 1 cm3. Dental CBCT and micro-CT scans were conducted on each specimen to obtain independent measurements of the following 4 trabecular bone structural parameters: bone volume fraction (BV/TV), specific bone surface (BS/BV), trabecular thickness (Tb.Th.), and trabecular separation (Tb.Sp.). Wilcoxon signed ranks tests were used to compare the measurement variations between the dental CBCT and micro-CT scans. A Spearman analysis was conducted to calculate the correlation coefficients (r) of the dental CBCT and micro-CT measurements. Of the 4 groups, the BV/TV and Tb.Th. measured using dental CBCT were larger compared with those measured using micro-CT. By contrast, the BS/BV measured using dental CBCT was significantly less compared with those measured using micro-CT. Furthermore, in the low-density groups (Groups 1 and 2), the Tb.Sp. measured using dental CBCT was smaller compared with those measured using micro-CT. However, the Tb.Sp. measured using dental CBCT was slightly larger in the high-density groups (Groups 3 and 4) than it was in the low density groups. The correlation coefficients between the BV/TV, BS/BV, Tb.Th., and Tb.Sp. values measured using dental CBCT and micro-CT were 0.9296 (p < .001), 0.8061 (p < .001), 0.9390 (p < .001), and 0.9583 (p < .001), respectively. Although the dental CBCT and micro-CT approaches exhibited high correlations, the absolute values of BV/TV, BS/BV, Tb.Th., Tb.Sp. differed significantly between these measurements. Additional studies must be conducted to evaluate using dental CBCT in clinical practice.

Direct estimation of human trabecular bone stiffness using cone beam computed tomography.

Science.gov (United States)

Klintström, Eva; Klintström, Benjamin; Pahr, Dieter; Brismar, Torkel B; Smedby, Örjan; Moreno, Rodrigo

2018-04-10

The aim of this study was to evaluate the possibility of estimating the biomechanical properties of trabecular bone through finite element simulations by using dental cone beam computed tomography data. Fourteen human radius specimens were scanned in 3 cone beam computed tomography devices: 3-D Accuitomo 80 (J. Morita MFG., Kyoto, Japan), NewTom 5 G (QR Verona, Verona, Italy), and Verity (Planmed, Helsinki, Finland). The imaging data were segmented by using 2 different methods. Stiffness (Young modulus), shear moduli, and the size and shape of the stiffness tensor were studied. Corresponding evaluations by using micro-CT were regarded as the reference standard. The 3-D Accuitomo 80 (J. Morita MFG., Kyoto, Japan) showed good performance in estimating stiffness and shear moduli but was sensitive to the choice of segmentation method. NewTom 5 G (QR Verona, Verona, Italy) and Verity (Planmed, Helsinki, Finland) yielded good correlations, but they were not as strong as Accuitomo 80 (J. Morita MFG., Kyoto, Japan). The cone beam computed tomography devices overestimated both stiffness and shear compared with the micro-CT estimations. Finite element-based calculations of biomechanics from cone beam computed tomography data are feasible, with strong correlations for the Accuitomo 80 scanner (J. Morita MFG., Kyoto, Japan) combined with an appropriate segmentation method. Such measurements might be useful for predicting implant survival by in vivo estimations of bone properties. Copyright © 2018 Elsevier Inc. All rights reserved.

18F-FET microPET and microMRI for anti-VEGF and anti-PlGF response assessment in an orthotopic murine model of human glioblastoma

DEFF Research Database (Denmark)

Nedergaard, Mette Kjoelhede; Michaelsen, Signe Regner; Urup, Thomas

2015-01-01

BACKGROUND: Conflicting data exist for anti-cancer effects of anti-placental growth factor (anti-PlGF) in combination with anti-VEGF. Still, this treatment combination has not been evaluated in intracranial glioblastoma (GBM) xenografts. In clinical studies, position emission tomography (PET) using......-FET MicroPET and MicroMRI for evaluation of anti-VEGF and anti-PlGF treatment response in GBM xenografts. METHODS: Mice with intracranial GBM were treated with anti-VEGF, anti-PlGF + anti-VEGF or saline. Bioluminescence imaging (BLI), 18F-FET MicroPET and T2-weighted (T2w)-MRI were used to follow tumour...... development. Primary end-point was survival, and tumours were subsequently analysed for Ki67 proliferation index and micro-vessel density (MVD). Further, PlGF and VEGFR-1 expression were examined in a subset of the xenograft tumours and in 13 GBM patient tumours. RESULTS: Anti-VEGF monotherapy increased...

High pressure-elevated temperature x-ray micro-computed tomography for subsurface applications.

Science.gov (United States)

Iglauer, Stefan; Lebedev, Maxim

2018-06-01

Physical, chemical and mechanical pore-scale (i.e. micrometer-scale) mechanisms in rock are of key importance in many, if not all, subsurface processes. These processes are highly relevant in various applications, e.g. hydrocarbon recovery, CO 2 geo-sequestration, geophysical exploration, water production, geothermal energy production, or the prediction of the location of valuable hydrothermal deposits. Typical examples are multi-phase flow (e.g. oil and water) displacements driven by buoyancy, viscous or capillary forces, mineral-fluid interactions (e.g. mineral dissolution and/or precipitation over geological times), geo-mechanical rock behaviour (e.g. rock compaction during diagenesis) or fines migration during water production, which can dramatically reduce reservoir permeability (and thus reservoir performance). All above examples are 3D processes, and 2D experiments (as traditionally done for micro-scale investigations) will thus only provide qualitative information; for instance the percolation threshold is much lower in 3D than in 2D. However, with the advent of x-ray micro-computed tomography (μCT) - which is now routinely used - this limitation has been overcome, and such pore-scale processes can be observed in 3D at micrometer-scale. A serious complication is, however, the fact that in the subsurface high pressures and elevated temperatures (HPET) prevail, due to the hydrostatic and geothermal gradients imposed upon it. Such HPET-reservoir conditions significantly change the above mentioned physical and chemical processes, e.g. gas density is much higher at high pressure, which strongly affects buoyancy and wettability and thus gas distributions in the subsurface; or chemical reactions are significantly accelerated at increased temperature, strongly affecting fluid-rock interactions and thus diagenesis and deposition of valuable minerals. It is thus necessary to apply HPET conditions to the aforementioned μCT experiments, to be able to mimic subsurface

Study of abscopal radiation effects on multicellular organisms; Etudes sur les effets a distance dans les organismes multicellulaires irradies

Energy Technology Data Exchange (ETDEWEB)

Ludwig, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

Amongst the lesions brought about by total body irradiation, two basically different types can be distinguished: those appearing in the area which has absorbed radiant energy and those emerging in areas remote from the irradiated tissues (abscopal effects). The abscopal effects are produced by toxic tissue breakdown products, which are removed by the bloodstream and interfere with particularly sensitive structures (radiotoxins). The radiotoxins mobilize other biologically active substances, interfering with the same tissues which may display abscopal effects. This is well established for the hormones of the adrenal cortex. Furthermore, important fractions of the radiotoxins are neutralized by the reticuloendothelial system. Temporary blockade of this system enhances the efficiency of radiotoxins and greatly increases mortality of the irradiated animals. One can therefore conclude that the reticuloendothelial system affords a natural defense against an essential reaction of total body irradiation: the effect of the radiotoxins. (author) [French] Les lesions consecutives a une irradiation peuvent etre classees en deux categories: celles qui se produisent au niveau du tissu irradie et celles qui apparaissent en dehors de celui-ci. Ces dernieres - appelees -'effets a distance'- sont dues a l'action de produits d'histolyse apparaissant au niveau du volume tissulaire ayant absorbe l'energie radiante, emportes par le courant sanguin et agissant sur des structures specialement receptives (Radiotoxines). Ces corps provoquait, dans des structures eloignees du siege de l'action locale du rayonnement, la secretion d'autres corps biologiquement actifs, capables d'agir sur les memes tissus pouvant presenter des effets a distance, compliquant ainsi leur mecanisme. Ceci est etabli pour les corticosteroides. De plus, des fractions importantes des radiotoxines sont neutralisees par le systeme reticuloendothelial. Puisque le blocage de ce systeme prolonge non seulement l'action des

Study of abscopal radiation effects on multicellular organisms; Etudes sur les effets a distance dans les organismes multicellulaires irradies

Energy Technology Data Exchange (ETDEWEB)

Ludwig, F. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

Amongst the lesions brought about by total body irradiation, two basically different types can be distinguished: those appearing in the area which has absorbed radiant energy and those emerging in areas remote from the irradiated tissues (abscopal effects). The abscopal effects are produced by toxic tissue breakdown products, which are removed by the bloodstream and interfere with particularly sensitive structures (radiotoxins). The radiotoxins mobilize other biologically active substances, interfering with the same tissues which may display abscopal effects. This is well established for the hormones of the adrenal cortex. Furthermore, important fractions of the radiotoxins are neutralized by the reticuloendothelial system. Temporary blockade of this system enhances the efficiency of radiotoxins and greatly increases mortality of the irradiated animals. One can therefore conclude that the reticuloendothelial system affords a natural defense against an essential reaction of total body irradiation: the effect of the radiotoxins. (author) [French] Les lesions consecutives a une irradiation peuvent etre classees en deux categories: celles qui se produisent au niveau du tissu irradie et celles qui apparaissent en dehors de celui-ci. Ces dernieres - appelees -'effets a distance'- sont dues a l'action de produits d'histolyse apparaissant au niveau du volume tissulaire ayant absorbe l'energie radiante, emportes par le courant sanguin et agissant sur des structures specialement receptives (Radiotoxines). Ces corps provoquait, dans des structures eloignees du siege de l'action locale du rayonnement, la secretion d'autres corps biologiquement actifs, capables d'agir sur les memes tissus pouvant presenter des effets a distance, compliquant ainsi leur mecanisme. Ceci est etabli pour les corticosteroides. De plus, des fractions importantes des radiotoxines sont neutralisees par le systeme reticuloendothelial. Puisque le blocage de ce

Dosimetry of ⁶⁴Cu-DOTA-AE105, a PET tracer for uPAR imaging

DEFF Research Database (Denmark)

Persson, Morten; El Ali, Henrik H.; Binderup, Tina

2014-01-01

64Cu-DOTA-AE105 is a novel positron emission tomography (PET) tracer specific to the human urokinase-type plasminogen activator receptor (uPAR). In preparation of using this tracer in humans, as a new promising method to distinguish between indolent and aggressive cancers, we have performed PET......, liver, kidney, spleen, intestine, muscle, bone and bladder. The activity concentrations in the mentioned organs [%ID/g] were used for the dosimetry calculation. The %ID/g of each organ at 1, 4.5 and 22h was scaled to human value based on a difference between organ and body weights. The scaled values...

Características do sistema produtivo da pecuária no município de Santarém, Pará Characterization of cattle production systems in Santarém, Pará, Brazil

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Antonio Humberto Hamad Minervino

2008-01-01

Full Text Available Com o objetivo de identificar as principais falhas no sistema de produção que limitam a pecuária em Santarém, Pará, foram entrevistados, ao acaso, 21 pecuaristas (90,5% de corte - cria, recria e engorda; 9,5% de leite, proprietários de 10% da população de bovinos do município. 71,4% das propriedades tinham currais para manejo do gado, entretanto apenas 38,1% possuíam balança e 23,8% tronco de contenção. A Brachiaria brizantha estava presente em todas as fazendas, sendo usada exclusivamente em 42,9% das propriedades. A disseminação de plantas invasoras (61,9% foi considerada a principal dificuldade no manejo das pastagens. Constatou-se que 76,2% dos pecuaristas utilizam misturas minerais com macro e micro-elementos, geralmente de formulações comerciais, enquanto que 19% utilizam apenas sal comum, enriquecido com micro-elementos. A concentração de fósforo (P na mistura mineral estava abaixo do recomendado para bovinos de corte em 76,9% das propriedades e apenas 19% das propriedades possuía cochos para suplementação mineral adequada.With the objective of identifying the main problems of cattle nutrition in the production systems of Santarém, Pará, Brazil, ranchers in different regions of the municipality and who owned 10% of the municipality's animals were interviewed at random. The ranchers raised mostly beef cattle; only 9.5% had dairy cattle. The infrastructure conditions are inappropriate; only 23.8% of the ranches have adequate facilities for beef cattle management and 61.9% of the ranchers do not consider weight control. Weed invasion was considered the main problem of the pastures (61.9%. The most common forage was Brachiaria brizantha, used exclusively in 42.9% of the ranches. 76.2% of the ranchers used a complete mineral supplement, with macro and micro elements, while 19% used only salt (NaCl with micro elements; the other 5% did not use mineral supplements at all. The phosphorus concentration in the mineral

Par Pond vegetation status Summer 1995 -- Summary

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1996-01-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the newly emergent, shoreline aquatic plant communities of Par Pond began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level. These surveys continued in July, September, and late October, 1995. Communities similar to the pre-drawdown, Par Pond aquatic plant communities are becoming re-established. Emergent beds of maidencane, lotus, waterlily, and watershield are extensive and well developed. Cattail occurrence continued to increase during the summer, but large beds common to Par Pond prior to the drawdown have not formed. Estimates from SPOT HRV, remote sensing satellite data indicated that as much as 120 hectares of emergent wetlands vegetation may have been present along the Par Pond shoreline by early October, 1995. To track the continued development of macrophytes in Par Pond, future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

Development of a micro-tomography technique by ion beams

International Nuclear Information System (INIS)

Moretto, Ph.; Michelet, C.

1997-01-01

The capability for an ion beam to penetrate easily the matter is an original feature for the nuclear microprobe analysis when compared to other techniques. Information in death of the sample can thus be obtained. Scanning Transmission Ion Microscopy (STIM) takes advantage of this capability to provide two dimensional maps of the sample thickness. Cross-sectional images of an object may be calculated from a set of STIM projections allowing the determination of the three-dimensional structure. This is the principle of STIM-Tomography. When PIXE analysis is carried out rotating the object under investigation, the elemental 3-D chemical distribution may also be elucidated at a microscopic scale. (authors)

Effects of lithium on extraction socket healing in rats assessed with micro-computed tomography.

Science.gov (United States)

Zeng, Yun Ting; Fu, Bin; Tang, Guo Hua; Zhang, Lei; Qian, Yu Fen

2013-09-01

Lithium is an activator of β-catenin signaling and β-catenin plays an important role in regulating bone formation and remodeling. The purpose of this study was to investigate the effects of lithium on bone repair in tooth extraction sockets in rats. Twenty male Wistar rats were subjected to maxillary left second molar extraction. The animals received a daily injection of lithium chloride (LiCl) or the same dose of sodium chloride (NaCl) starting 7 days before tooth extraction until sacrifice 14 days after extraction. Rats were randomly divided into: (1) a pre-treated group that received LiCl injection from 7 days before to 3 days after tooth extraction; (2) a post-treated group that received LiCl injection starting 4 days after tooth extraction; (3) a continuously treated group that received LiCl injection for the entire 21 days; and (4) a control group that received NaCl injection only. The volume of new bone and the bone density in the extraction socket were quantified by micro-computed tomography. The percentage of new bone formation in the extraction socket was as follows: 63.2 ± 13.4% (pre-treated group), 53.9 ± 9.8% (post-treated), 23.8 ± 8.0% (continuously treated) and 37.5 ± 4.2% (control). The difference in percentage was statistically significant between each pair of groups. Pre- and post-treated groups also showed a significant increase in the density of new bone. Lithium enhances bone repair in extraction sockets when delivered before or after tooth extraction. Tooth extraction during lithium treatment may impair bone healing.

La erosión y sus implicaciones en la morfología de la micro cuenca del Igarapé Apeú, Estado do Pará, Brasil

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de Oliveira Santos Odete Cardoso

2007-11-01

Full Text Available Las aguas de los canales que componen la micro cuenca del canal Apeú, ubicada en el nordeste del estado del Pará, en tierras de los municipios de Castanhal (70%, Inhangapí (10% y Santa Isabel do Pará (20%, son muy aprovechadas por los ribereños y pequeños campesinos. Por eso, en esta investigación se muestra que la erosión acelerada por las actividades antrópicas contribuye a los cambios de la morfología de los canales fluviales que componen la microcuenca. Para medir la erosión en pendiente se empleó la metodología de las estacas; para la erosión marginal en los canales se utilizó la metodología de los Pinos y de las Estacas. Los análisis fisicoquímicas de los sedimentos de los barrancos y del fondo de los canales fueron determinados por las técnicas descriptas por Guimarães et al. (1970, EMBRAPA (1997 y Silva (1999. Laprofundidad de los canales se midió usando el molinete en vado, en el momento de las mediciones de los caudales en las secciones transversales de los canales. De acuerdo con los resultados, la pérdida de suelo por la erosión de la pendiente llegó a 74,02 m en el periodo de octubre de 2002 a julio de 2003. El canal Apeú, el principal de la microcuenca, en la hacienda Morro Verde abandonó su lecho normal por espacio de 50 metros, a causa de los sedimentos provenientes de surcos, zanjas y barrancos formados en el interior de la hacienda mencionada. En ese mismo canal, en el periodo menos lluvioso, en la villa agrícola de Macapazinho, en la mitad del lecho, el nivel de las aguas alcanzó 0,5 m; en el periodo lluvioso llegó a 3,0 m. En los canales predomina la carga del lecho.

ParABS system in chromosome partitioning in the bacterium Myxococcus xanthus.

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Antonio A Iniesta

Full Text Available Chromosome segregation is an essential cellular function in eukaryotic and prokaryotic cells. The ParABS system is a fundamental player for a mitosis-like process in chromosome partitioning in many bacterial species. This work shows that the social bacterium Myxococcus xanthus also uses the ParABS system for chromosome segregation. Its large prokaryotic genome of 9.1 Mb contains 22 parS sequences near the origin of replication, and it is shown here that M. xanthus ParB binds preferentially to a consensus parS sequence in vitro. ParB and ParA are essential for cell viability in M. xanthus as in Caulobacter crescentus, but unlike in many other bacteria. Absence of ParB results in anucleate cells, chromosome segregation defects and loss of viability. Analysis of ParA subcellular localization shows that it clusters at the poles in all cells, and in some, in the DNA-free cell division plane between two chromosomal DNA masses. This ParA localization pattern depends on ParB but not on FtsZ. ParB inhibits the nonspecific interaction of ParA with DNA, and ParA colocalizes with chromosomal DNA only when ParB is depleted. The subcellular localization of ParB suggests a single ParB-parS complex localized at the edge of the nucleoid, next to a polar ParA cluster, with a second ParB-parS complex migrating after the replication of parS takes place to the opposite nucleoid edge, next to the other polar ParA cluster.

Compressive Phase Contrast Tomography

International Nuclear Information System (INIS)

Maia, Filipe; MacDowell, Alastair; Marchesini, Stefano; Padmore, Howard A.; Parkinson, Dula Y.; Pien, Jack; Schirotzek, Andre; Yang, Chao

2010-01-01

When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. Interference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher contrast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).

Micro-mechanical properties of different sites on woodpecker's skull.

Science.gov (United States)

Ni, Yikun; Wang, Lizhen; Liu, Xiaoyu; Zhang, Hongquan; Lin, Chia-Ying; Fan, Yubo

2017-11-01

The uneven distributed microstructure featured with plate-like spongy bone in woodpecker's skull has been found to further help reduce the impact during woodpecker's pecking behavior. Therefore, this work was to investigate the micro-mechanical properties and composition on different sites of Great Spotted woodpecker's (GSW) skull. Different sites were selected on forehead, tempus and occiput, which were also compared with those of Eurasian Hoopoe (EH) and Lark birds (LB). Micro structural parameters assessed from micro computed tomography (μCT) occurred significantly difference between GSW, EH and LB. The micro finite element (micro-FE) models were developed and the simulation was performed as a compression process. The maximal stresses of GSW's micro-FE models were all lower than those of EH and LB respectively and few concentrated stresses were noticed on GSW's trabecular bone. Fourier transform infrared mapping suggesting a greater organic content in the occiput of GSW's cranial bone compared with others. The nano-hardness of the GSW's occiput was decreasing from forehead to occiput. The mechanical properties, site-dependent hardness distribution and special material composition of GSW's skull bone are newly found in this study. These factors may lead to a new design of bulk material mimicking these characteristics.

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

Science.gov (United States)

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  .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.

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

Science.gov (United States)

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

Advanced Exploration Technologies: Micro and Nano Technologies Enabling Space Missions in the 21st Century

Science.gov (United States)

Krabach, Timothy

1998-01-01

Some of the many new and advanced exploration technologies which will enable space missions in the 21st century and specifically the Manned Mars Mission are explored in this presentation. Some of these are the system on a chip, the Computed-Tomography imaging Spectrometer, the digital camera on a chip, and other Micro Electro Mechanical Systems (MEMS) technology for space. Some of these MEMS are the silicon micromachined microgyroscope, a subliming solid micro-thruster, a micro-ion thruster, a silicon seismometer, a dewpoint microhygrometer, a micro laser doppler anemometer, and tunable diode laser (TDL) sensors. The advanced technology insertion is critical for NASA to decrease mass, volume, power and mission costs, and increase functionality, science potential and robustness.

Study of a micro-sublimation apparatus with removal of the vapours by pumping; application to the analysis of fluorinated products (1963); Etude d'un appareillage de microsublimation avec entrainement des vapeurs par pompage et application a l'analyse des produits fluores (1963)

Energy Technology Data Exchange (ETDEWEB)

Delvalle, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-07-01

Micro-sublimation analysis presents definite advantages both from the qualitative and quantitative points of view. An automatic micro-sublimation analysis apparatus has been developed for the analysis of fluorinated products (ClF{sub 3}, HF, UF{sub 6}, etc.) but this is only one particular application of a method which has a far wider field of possible applications. We give first the most favorable conditions for the operation of such an apparatus. These conditions are the use of a detector which is linear and independent of the nature of the gas, the flow of the sublimed vapours in the conditions of molecular flow, and finally a reproducible and linear re-heating of the separating trap. The apparatus thus built has the advantage of yielding any analysis without prior calibration. It also makes possible the easy identification of an unknown product by the determination of its vapour pressure curve and its molecular weight. The analysis of fluorinated products with this apparatus has shown that the experimental results agree well with what is expected. (author) [French] L'analyse par microsublimation presente un interet certain tant au point de vue qualitatif que quantitatif. Nous avons mis au point un appareillage automatique d'analyse par microsublimation pour l'analyse des produits fluores (CIF{sub 3}, HF, UF{sub 6}, etc.) mais il ne s'agit que de l'application a un cas particulier d'une methode ayant un champ d'applications bien plus vaste. Nous exposons tout d'abord les conditions les plus favorables au bon fonctionnement d'un tel appareil. Ces conditions sont l'emploi d'un detecteur lineaire et independant de la nature du gaz, l'ecoulement des vapeurs sublimees en regime moleculaire et enfin un rechauffage reproductible et lineaire du piege separateur. L'appareil ainsi realise presente l'avantage d'effectuer une analyse quelconque sans etalonnage prealable. Il permet en outre d'identifier aisement un corps inconnu par la determination de sa courbe de tension

In Vivo Respiratory-Gated Micro-CT Imaging in Small-Animal Oncology Models

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Dawn Cavanaugh

2004-01-01

Full Text Available Micro-computed tomography (micro-CT is becoming an accepted research tool for the noninvasive examination of laboratory animals such as mice and rats, but to date, in vivo scanning has largely been limited to the evaluation of skeletal tissues. We use a commercially available micro-CT device to perform respiratory gated in vivo acquisitions suitable for thoracic imaging. The instrument is described, along with the scan protocol and animal preparation techniques. Preliminary results confirm that lung tumors as small as 1 mm in diameter are visible in vivo with these methods. Radiation dose was evaluated using several approaches, and was found to be approximately 0.15 Gy for this respiratory-gated micro-CT imaging protocol. The combination of high-resolution CT imaging and respiratory-gated acquisitions appears well-suited to serial in vivo scanning.

Imaging of metastatic lymph nodes by X-ray phase-contrast micro-tomography

DEFF Research Database (Denmark)

Jensen, Torben Haugaard; Bech, Martin; Binderup, Tina

2013-01-01

-contrast tomography. Ten lymph nodes had metastatic deposits and 7 were benign. The phase-contrast images were analyzed according to standards for conventional CT images looking for characteristics usually only visible by pathological examinations. Histopathology was used as reference. The result of this study...

Analysis of ParB-centromere interactions by multiplex SPR imaging reveals specific patterns for binding ParB in six centromeres of Burkholderiales chromosomes and plasmids.

Science.gov (United States)

Pillet, Flavien; Passot, Fanny Marie; Pasta, Franck; Anton Leberre, Véronique; Bouet, Jean-Yves

2017-01-01

Bacterial centromeres-also called parS, are cis-acting DNA sequences which, together with the proteins ParA and ParB, are involved in the segregation of chromosomes and plasmids. The specific binding of ParB to parS nucleates the assembly of a large ParB/DNA complex from which ParA-the motor protein, segregates the sister replicons. Closely related families of partition systems, called Bsr, were identified on the chromosomes and large plasmids of the multi-chromosomal bacterium Burkholderia cenocepacia and other species from the order Burkholeriales. The centromeres of the Bsr partition families are 16 bp palindromes, displaying similar base compositions, notably a central CG dinucleotide. Despite centromeres bind the cognate ParB with a narrow specificity, weak ParB-parS non cognate interactions were nevertheless detected between few Bsr partition systems of replicons not belonging to the same genome. These observations suggested that Bsr partition systems could have a common ancestry but that evolution mostly erased the possibilities of cross-reactions between them, in particular to prevent replicon incompatibility. To detect novel similarities between Bsr partition systems, we have analyzed the binding of six Bsr parS sequences and a wide collection of modified derivatives, to their cognate ParB. The study was carried out by Surface Plasmon Resonance imaging (SPRi) mulitplex analysis enabling a systematic survey of each nucleotide position within the centromere. We found that in each parS some positions could be changed while maintaining binding to ParB. Each centromere displays its own pattern of changes, but some positions are shared more or less widely. In addition from these changes we could speculate evolutionary links between these centromeres.

La pelade par plaques

Science.gov (United States)

Spano, Frank; Donovan, Jeff C.

2015-01-01

Résumé Objectif Présenter aux médecins de famille des renseignements de base pour faire comprendre l’épidémiologie, la pathogenèse, l’histologie et l’approche clinique au diagnostic de la pelade par plaques. Sources des données Une recension a été effectuée dans PubMed pour trouver des articles pertinents concernant la pathogenèse, le diagnostic et le pronostic de la pelade par plaques. Message principal La pelade par plaques est une forme de perte pileuse auto-immune dont la prévalence durant une vie est d’environ 2 %. Des antécédents personnels ou familiaux de troubles auto-immuns concomitants, comme le vitiligo ou une maladie de la thyroïde, peuvent être observés dans un petit sous-groupe de patients. Le diagnostic peut souvent être posé de manière clinique en se fondant sur la perte de cheveux non cicatricielle et circulaire caractéristique, accompagnée de cheveux en « point d’exclamation » en périphérie chez ceux dont le problème en est aux premiers stades. Le diagnostic des cas plus complexes ou des présentations inhabituelles peut être facilité par une biopsie et un examen histologique. Le pronostic varie largement et de mauvais résultats sont associés à une apparition à un âge précoce, une perte importante, la variante ophiasis, des changements aux ongles, des antécédents familiaux ou des troubles auto-immuns concomitants. Conclusion La pelade par plaques est une forme auto-immune de perte de cheveux périodiquement observée en soins primaires. Les médecins de famille sont bien placés pour identifier la pelade par plaques, déterminer la gravité de la maladie et poser le diagnostic différentiel approprié. De plus, ils sont en mesure de renseigner leurs patients à propos de l’évolution clinique de la maladie ainsi que du pronostic général selon le sous-type de patients.

Longitudinal in vivo evaluation of bone regeneration by combined measurement of multi-pinhole SPECT and micro-CT for tissue engineering

Science.gov (United States)

Lienemann, Philipp S.; Metzger, Stéphanie; Kiveliö, Anna-Sofia; Blanc, Alain; Papageorgiou, Panagiota; Astolfo, Alberto; Pinzer, Bernd R.; Cinelli, Paolo; Weber, Franz E.; Schibli, Roger; Béhé, Martin; Ehrbar, Martin

2015-05-01

Over the last decades, great strides were made in the development of novel implants for the treatment of bone defects. The increasing versatility and complexity of these implant designs request for concurrent advances in means to assess in vivo the course of induced bone formation in preclinical models. Since its discovery, micro-computed tomography (micro-CT) has excelled as powerful high-resolution technique for non-invasive assessment of newly formed bone tissue. However, micro-CT fails to provide spatiotemporal information on biological processes ongoing during bone regeneration. Conversely, due to the versatile applicability and cost-effectiveness, single photon emission computed tomography (SPECT) would be an ideal technique for assessing such biological processes with high sensitivity and for nuclear imaging comparably high resolution (designed poly(ethylene glycol)-based hydrogels that release bone morphogenetic protein to guide the healing of critical sized calvarial bone defects. By combined in vivo longitudinal multi-pinhole SPECT and micro-CT evaluations we determine the spatiotemporal course of bone formation and remodeling within this synthetic hydrogel implant. End point evaluations by high resolution micro-CT and histological evaluation confirm the value of this approach to follow and optimize bone-inducing biomaterials.

Keratometric alterations following the 25-gauge transconjunctival sutureless pars plana vitrectomy versus the conventional pars plana vitrectomy.

Science.gov (United States)

Citirik, Mehmet; Batman, Cosar; Bicer, Tolga; Zilelioglu, Orhan

2009-09-01

To assess the alterations in keratometric astigmatism following the 25-gauge transconjunctival sutureless pars plana vitrectomy versus the conventional pars plana vitrectomy. Sixteen consecutive patients were enrolled into the study. Conventional vitrectomy was applied to eight of the cases and 25-gauge transconjunctival sutureless vitrectomy was performed in eight patients. Keratometry was performed before and after the surgery. In the 25-gauge transconjunctival sutureless pars plana vitrectomy group, statistically significant changes were not observed in the corneal curvature in any post-operative follow-up measurement (p > 0.05); whereas in the conventional pars plana vitrectomy group, statistically significant changes were observed in the first postoperative day (p = 0.01) and first postoperative month (p = 0.03). We noted that these changes returned to baseline in three months (p = 0.26). Both 25-gauge transconjunctival sutureless and conventional pars plana vitrectomy are effective surgical modalities for selected diseases of the posterior segment. Surgical procedures are critical for the visual rehabilitation of the patients. The post-operative corneal astigmatism of the vitrectomised eyes can be accurately determined at least two months post-operatively.

Centromere pairing by a plasmid-encoded type I ParB protein

DEFF Research Database (Denmark)

Ringgaard, Simon; Löwe, Jan; Gerdes, Kenn

2007-01-01

The par2 locus of Escherichia coli plasmid pB171 encodes two trans-acting proteins, ParA and ParB, and two cis-acting sites, parC1 and parC2, to which ParB binds cooperatively. ParA is related to MinD and oscillates in helical structures and thereby positions ParB/parC-carrying plasmids regularly......, hence identifying the N terminus of ParB as a requirement for ParB-mediated centromere pairing. These observations suggest that centromere pairing is an important intermediate step in plasmid partitioning mediated by the common type I loci....

Analysis of ParB-centromere interactions by multiplex SPR imaging reveals specific patterns for binding ParB in six centromeres of Burkholderiales chromosomes and plasmids.

Directory of Open Access Journals (Sweden)

Flavien Pillet

Full Text Available Bacterial centromeres-also called parS, are cis-acting DNA sequences which, together with the proteins ParA and ParB, are involved in the segregation of chromosomes and plasmids. The specific binding of ParB to parS nucleates the assembly of a large ParB/DNA complex from which ParA-the motor protein, segregates the sister replicons. Closely related families of partition systems, called Bsr, were identified on the chromosomes and large plasmids of the multi-chromosomal bacterium Burkholderia cenocepacia and other species from the order Burkholeriales. The centromeres of the Bsr partition families are 16 bp palindromes, displaying similar base compositions, notably a central CG dinucleotide. Despite centromeres bind the cognate ParB with a narrow specificity, weak ParB-parS non cognate interactions were nevertheless detected between few Bsr partition systems of replicons not belonging to the same genome. These observations suggested that Bsr partition systems could have a common ancestry but that evolution mostly erased the possibilities of cross-reactions between them, in particular to prevent replicon incompatibility. To detect novel similarities between Bsr partition systems, we have analyzed the binding of six Bsr parS sequences and a wide collection of modified derivatives, to their cognate ParB. The study was carried out by Surface Plasmon Resonance imaging (SPRi mulitplex analysis enabling a systematic survey of each nucleotide position within the centromere. We found that in each parS some positions could be changed while maintaining binding to ParB. Each centromere displays its own pattern of changes, but some positions are shared more or less widely. In addition from these changes we could speculate evolutionary links between these centromeres.

In vitro Quinolones Susceptibility Analysis of Chinese Mycoplasma bovis Isolates and their Phylogenetic Scenarios based upon QRDRs of DNA Topoisomerases Revealing a Unique Transition in ParC

Directory of Open Access Journals (Sweden)

Riaz Mustafa1,2,3, Jingjing Qi1,2, Xiaoliang Ba1,2, Yingyu Chen1,4, Changmin Hu1,2, Xiaole Liu1,2, Lingling Tu5, Qingjie Peng5, Huanchun Chen1,2 and Aizhen Guo1,2*

2013-07-01

Full Text Available Mycoplasma bovis can cause different systemic problems in cattle, and recently has been resulted in huge economic losses in China. In vitro susceptibilities of 26 twice sub-cultured Chinese M. bovis field isolates were determined at physiological pH including PG45 through broth micro-dilution method. Except Huanggang isolate, all isolates and PG45 were in the sensitive range for levofloxacin, lomefloxacin and ciprofloxacin, whereas, for norfloxacin and nalidixic acid, they had shown intermediate resistant and complete resistant patterns, respectively. The multiple sequence analysis revealed point mutations in QRDRs of gyrA and parC genes of Huanggang isolate resulting in amino acid substitutions at positions 83 (S-F in GyrA (E. coli numbering and 80 (S-I in ParC proteins, the latter is reported for first time in M. bovis. Conclusively, fluoroquinolones are the potential veterinary therapeutic agents for mycoplasmosis in China and resistance to these agents comes through point mutations in QRDRs of gyrA and parC genes with ParC and GyrA mutation orientation.

Dual filtered backprojection for micro-rotation confocal microscopy

International Nuclear Information System (INIS)

Laksameethanasan, Danai; Brandt, Sami S; Renaud, Olivier; Shorte, Spencer L

2009-01-01

Micro-rotation confocal microscopy is a novel optical imaging technique which employs dielectric fields to trap and rotate individual cells to facilitate 3D fluorescence imaging using a confocal microscope. In contrast to computed tomography (CT) where an image can be modelled as parallel projection of an object, the ideal confocal image is recorded as a central slice of the object corresponding to the focal plane. In CT, the projection images and the 3D object are related by the Fourier slice theorem which states that the Fourier transform of a CT image is equal to the central slice of the Fourier transform of the 3D object. In the micro-rotation application, we have a dual form of this setting, i.e. the Fourier transform of the confocal image equals the parallel projection of the Fourier transform of the 3D object. Based on the observed duality, we present here the dual of the classical filtered back projection (FBP) algorithm and apply it in micro-rotation confocal imaging. Our experiments on real data demonstrate that the proposed method is a fast and reliable algorithm for the micro-rotation application, as FBP is for CT application

CFD analysis of PAR performance as function of inlet design

International Nuclear Information System (INIS)

Park, Kweonha; Khor, Chong Lee

2016-01-01

Highlights: • The new concept of PAR (passive autocatalytic recombiner) was proposed and analyzed. • Guidance wall was added at the bottom of PAR to enhance the flow rate through the catalyst. • The new concept of PAR was proved to have a better hydrogen removal performance. - Abstract: Passive autocatalytic recombiner (PAR) is very useful hydrogen mitigation measurement. It is widely implemented in the current and advanced light water reactors (ALWRs). The design of the PARs should be optimized for the specific use under severe accident scenarios. Several techniques and innovations have been fused into the PAR, as an effort to increase its efficiency of hydrogen mitigation. This study proposes different concepts of PAR, which applied some changes to the honeycomb catalyst PAR made by the Korea Nuclear Technology (KNT) Inc. Two slices of plate are added to the bottom of PAR model, which intended to act as a reflection wall and promote the gas flow into PAR. Hydrogen volume fraction was given 4 vol. % which tested by KNT to investigate the performance of PAR in different direction gas flow conditions to see maximum hydrogen recombination rate. The new concept of PAR was proved to have a better hydrogen removal performance compared to the original honeycomb catalyst PAR.

CFD analysis of PAR performance as function of inlet design

Energy Technology Data Exchange (ETDEWEB)

Park, Kweonha, E-mail: khpark@kmou.ac.kr [Division of Mechanical and Energy systems Engineering, Korea Maritime University, Dongsam-dong, Yeongdo-gu, Busan 606-791 (Korea, Republic of); Khor, Chong Lee, E-mail: itachi_829@hotmail.com [Department of Mechanical Engineering, Korea Maritime University (Korea, Republic of)

2016-01-15

Highlights: • The new concept of PAR (passive autocatalytic recombiner) was proposed and analyzed. • Guidance wall was added at the bottom of PAR to enhance the flow rate through the catalyst. • The new concept of PAR was proved to have a better hydrogen removal performance. - Abstract: Passive autocatalytic recombiner (PAR) is very useful hydrogen mitigation measurement. It is widely implemented in the current and advanced light water reactors (ALWRs). The design of the PARs should be optimized for the specific use under severe accident scenarios. Several techniques and innovations have been fused into the PAR, as an effort to increase its efficiency of hydrogen mitigation. This study proposes different concepts of PAR, which applied some changes to the honeycomb catalyst PAR made by the Korea Nuclear Technology (KNT) Inc. Two slices of plate are added to the bottom of PAR model, which intended to act as a reflection wall and promote the gas flow into PAR. Hydrogen volume fraction was given 4 vol. % which tested by KNT to investigate the performance of PAR in different direction gas flow conditions to see maximum hydrogen recombination rate. The new concept of PAR was proved to have a better hydrogen removal performance compared to the original honeycomb catalyst PAR.

Positron emission tomography: Which indications, which benefits?; Tomographie par emission de positons (TEP): quelles indications, quels benefices?

Energy Technology Data Exchange (ETDEWEB)

Chassoux, F. [Ctr Hosp St Anne, Serv Neurochirurg, F-75014 Paris (France); Chassoux, F.; Chiron, C. [CEA, I2BM, Serv Hosp Frederic Joliot, F-91 Orsay (France); Chiron, C. [Hop Necker Enfants Malad, INSERM, U663, F-75015 Paris (France); Chassoux, F.; Chiron, C. [Univ Paris 06, F-75005 Paris (France)

2008-07-01

Positron emission tomography (PET) is currently used in the pre-surgical workup for drug-resistant partial epilepsies in addition to MRI. Inter-ictal metabolism is studied in clinical practice using {sup 18}fluoro-desoxy-glucose ({sup 18}FDG). In medial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis, hypo-metabolism ipsilateral to the epileptogenic focus is found in 70-90% of cases. However, hypo-metabolism is larger than the structural lesion observed on MRI and includes the epileptogenic zone and ictal discharge spread areas. Hypo-metabolism is related to surgical outcome and cognitive disturbances in MTLE. Although the usefulness of PET appears less well-established in extra-temporal lobe epilepsy and in children, its sensitivity may be improved by co-registration and superimposition of PET on MRI at any age. Focal hypo-metabolism can be easily detected by visual analysis, allowing detection of minor gyral abnormalities that may correspond to focal cortical dysplasias. Moreover, in cases of negative MRI, focal hypo-metabolism findings may help invasive monitoring planning and deep electrode placement for SEEG, and finally improve surgical outcome. (authors)

Par Pond Fish, Water, and Sediment Chemistry

International Nuclear Information System (INIS)

Paller, M.H.; Wike, L.D.

1996-06-01

The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond

Par Pond Fish, Water, and Sediment Chemistry

Energy Technology Data Exchange (ETDEWEB)

Paller, M.H. [Westinghouse Savannah River Company, AIKEN, SC (United States); Wike, L.D.

1996-06-01

The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond.

In-vivo imaging of blood flow dynamics using color Doppler optical coherence tomography

Science.gov (United States)

Yazdanfar, Siavash; Rollins, Andrew M.; Izatt, Joseph A.

2000-04-01

Noninvasive quantitation of blood flow in the retinal micro circulation may elucidate the progression and treatment of ocular disorders including diabetic retinopathy, age-related degeneration, and glaucoma. Color Doppler optical coherence tomography was recently introduced as a technique allowing simultaneous micron-scale resolution cross-sectional imaging of tissue micro structure and blood flow in the human retina. Here, time-resolved imaging of dynamics of blood flow profiles was performed to measure cardiac pulsatility within retinal vessels. Retinal pulsatility has been shown to decrease throughout the progression of diabetic retinopathy.

Concerning the dynamic instability of actin homolog ParM

International Nuclear Information System (INIS)

Popp, David; Yamamoto, Akihiro; Iwasa, Mitsusada; Narita, Akihiro; Maeda, Kayo; Maeda, Yuichiro

2007-01-01

Using in vitro TIRF- and electron-microscopy, we reinvestigated the dynamics of native ParM, a prokaryotic DNA segregation protein and actin homolog. In contrast to a previous study, which used a cysteine ParM mutant, we find that the polymerization process of wild type ATP-ParM filaments consists of a polymerization phase and a subsequent steady state phase, which is dynamically unstable, like that of microtubules. We find that the apparent bidirectional polymerization of ParM, is not due to the intrinsic nature of this filament, but results from ParM forming randomly oriented bundles in the presence of crowding agents. Our results imply, that in the bacterium, ParM filaments spontaneously form bipolar bundles. Due to their intrinsic dynamic instability, ParM bundles can efficiently 'search' the cytoplasmic lumen for DNA, bind it equally well at the bipolar ends and segregate it approximately symmetrically, by the insertion of ParM subunits at either end

Development of radiotracers for imaging NR2B subtype NMDA receptors with positron emission tomography; Developpement de radiotraceurs pour la visualisation des recepteurs NMDA de sous-type NR2B par tomographie par emission de positons

Energy Technology Data Exchange (ETDEWEB)

Labas, R

2007-07-01

The aim of this thesis was to develop new radioactive tracers for imaging NR2B subtype NMDA receptors with positron emission tomography. Several compounds including 4-(4-fluoro-benzyl)piperidine and presenting interesting in vivo biological properties were the object of a labelling with a positrons emitter atom ({sup 11}C or {sup 18}F)

Imaging neutrophil migration dynamics using micro-optical coherence tomography (Conference Presentation)

Science.gov (United States)

Chu, Kengyeh K.; Yonker, Lael; Som, Avira; Pazos, Michael; Kusek, Mark E.; Hurley, Bryan P.; Tearney, Guillermo J.

2016-03-01

Neutrophils are immune cells that undergo chemotaxis, detecting and migrating towards a chemical signal gradient. Neutrophils actively migrate across epithelial boundaries, interacting with the epithelium to selectively permit passage without compromising the epithelial barrier. In many inflammatory disorders, excessive neutrophil migration can cause damage to the epithelium itself. The signaling pathways and mechanisms that facilitate trans-epithelial migration are not fully characterized. Our laboratory has developed micro-optical coherence tomography (μOCT), which has 2 μm lateral resolution and 1 μm axial resolution. As a high-resolution native contrast modality, μOCT can directly visualize individual neutrophils as they interact with a cell layer cultured on a transwell filter. A chemoattractant can be applied to the apical side of inverted monolayer, and human neutrophils placed in the basolateral compartment, while μOCT captures 3D images of the chemotaxis. μOCT images can also generate quantitative metrics of migration volume to study the dependence of chemotaxis on monolayer cell type, chemoattractant type, and disease state of the neutrophils. For example, a disease known as leukocyte adhesion deficiency (LAD) can be simulated by treating neutrophils with antibodies that interfere with the CD18 receptor, a facilitator of trans-epithelial migration. We conducted a migration study of anti-CD18 treated and control neutrophils using T84 intestinal epithelium as a barrier. After one hour, μOCT time-lapse imaging indicated a strong difference in the fraction of neutrophils that remain attached to the epithelium after migration (0.67 +/- 0.12 attached anti-CD18 neutrophils, 0.23 +/- 0.08 attached control neutrophils, n = 6, p < 0.05), as well as a modest but non-significant decrease in total migration volume for treated neutrophils. We can now integrate μOCT-derived migration metrics with simultaneously acquired measurements of transepithelial electrical

uPAR as anti-cancer target

DEFF Research Database (Denmark)

Lund, Ida K; Illemann, Martin; Thurison, Tine

2011-01-01

, and a potential diagnostic and predictive impact of the different uPAR forms has been reported. Hence, pericellular proteolysis seems to be a suitable target for anti-cancer therapy and numerous approaches have been pursued. Targeting of this process may be achieved by preventing the binding of uPA to u...... using mouse monoclonal antibodies (mAbs) against mouse uPA or uPAR. These reagents will target uPA and uPAR in both stromal cells and cancer cells, and their therapeutic potential can now be assessed in syngenic mouse cancer models....

Protease-activated receptor (PAR2, but not PAR1, is involved in collateral formation and anti-inflammatory monocyte polarization in a mouse hind limb ischemia model.

Directory of Open Access Journals (Sweden)

Lisa G van den Hengel

Full Text Available AIMS: In collateral development (i.e. arteriogenesis, mononuclear cells are important and exist as a heterogeneous population consisting of pro-inflammatory and anti-inflammatory/repair-associated cells. Protease-activated receptor (PAR1 and PAR2 are G-protein-coupled receptors that are both expressed by mononuclear cells and are involved in pro-inflammatory reactions, while PAR2 also plays a role in repair-associated responses. Here, we investigated the physiological role of PAR1 and PAR2 in arteriogenesis in a murine hind limb ischemia model. METHODS AND RESULTS: PAR1-deficient (PAR1-/-, PAR2-deficient (PAR2-/- and wild-type (WT mice underwent femoral artery ligation. Laser Doppler measurements revealed reduced post-ischemic blood flow recovery in PAR2-/- hind limbs when compared to WT, while PAR1-/- mice were not affected. Upon ischemia, reduced numbers of smooth muscle actin (SMA-positive collaterals and CD31-positive capillaries were found in PAR2-/- mice when compared to WT mice, whereas these parameters in PAR1-/- mice did not differ from WT mice. The pool of circulating repair-associated (Ly6C-low monocytes and the number of repair-associated (CD206-positive macrophages surrounding collaterals in the hind limbs were increased in WT and PAR1-/- mice, but unaffected in PAR2-/- mice. The number of repair-associated macrophages in PAR2-/- hind limbs correlated with CD11b- and CD115-expression on the circulating monocytes in these animals, suggesting that monocyte extravasation and M-CSF-dependent differentiation into repair-associated cells are hampered. CONCLUSION: PAR2, but not PAR1, is involved in arteriogenesis and promotes the repair-associated response in ischemic tissues. Therefore, PAR2 potentially forms a new pro-arteriogenic target in coronary artery disease (CAD patients.

Micro-processus et macro-structures

Directory of Open Access Journals (Sweden)

Aaron Victor Cicourel

2008-10-01

Full Text Available Des approches sociologiques traditionnelles ont défini des macro-structures sociales comme un niveau particulier de la réalité sociale, à distinguer des micro-épisodes de l’action sociale. Cela les a conduits à concevoir ces macro-structures et à mener des recherches sur elles de manière plus ou moins indépendante des pratiques observables de la vie quotidienne. Cicourel soutient que les faits (macro-sociaux ne sont pas simplement donnés, mais émergent de pratiques routinières de la vie de tous les jours. Le macro, au sens de descriptions résumées, hors contexte, normalisées et typifiées, est un produit typique des procédures interactives et organisationnelles qui transforment les micro-événements en structures macro-sociales. Ainsi une précondition pour l’intégration des phénomènes micro- et macro-sociaux dans notre théorie et dans notre méthodologie renvoie à l’identification des processus contribuant à la création de macro-structures par des inférences routinières, des interprétations et des procédure de résumé. Le texte montre aussi que les différences entre approches micro-sociologiques apparaissent parallèles à celles existant entre approches micro et macro. On se centrant sur de petits fragments d’interactions conversationnelles, certains travaux micro-sociologiques tendent à ignorer ce qui informe ces interactions conversationnelles pour les participants eux-mêmes. Les comptes rendus décontextualisés produits par de telles méthodes ressemblent à la décontextualisation résultant des procédures macro-sociologiques d’agrégation. Contre cela, Cicourel défend la constitution de bases de données comparatives n’incluant pas seulement le contexte des interactions de face à face, mais étudiant aussi les phénomènes sociaux de manière systématique à travers différents contextes.Micro-processes and macro-structures. Notes on articulation between different levels of analysis

Apoplejía pituitaria con parálisis del III par craneal: Reporte de caso

Directory of Open Access Journals (Sweden)

Miguel Pinto Valdivia

2011-10-01

Full Text Available Se describe el caso de un varón de 65 años de edad, sin antecedentes patológicos de importancia, que acudió a emergencia del Hospital Nacional Cayetano Heredia por presentar cefalea intensa y ptosis palpebral izquierda. El examen físico mostró parálisis aislada del III par craneal izquierdo. Los análisis de laboratorio mostraron hiponatremia e hipopituitarismo y la resonancia magnética nuclear un adenoma pituitario con áreas de hemorragia e invasión de los senos cavernosos. El tratamiento incluyó glucocorticoides y descompresión quirúrgica transesfenoidal. La anatomía patológica confirmó el diagnóstico de infarto hemorrágico de un adenoma pituitario. El paciente fue dado de alta con terapia sustitutiva de levotiroxina y prednisona. La ptosis palpebral izquierda se recuperó en forma parcial. La apoplejía pituitaria es un síndrome clínico producido por un proceso expansivo dentro de la silla turca, secundario a hemorragia o infarto de un adenoma pituitario, que se caracteriza por cefalea, déficit visual, oftalmoplejía y alteración del nivel de conciencia. Este proceso expansivo puede comprimir los pares craneales en los senos cavernosos, produciendo diferentes grados de parálisis de los músculos oculomotores. La parálisis aislada del III par craneal es rara.(Rev Med Hered 2011;22:186-189.

Copenhagen uPAR prostate cancer (CuPCa) database

DEFF Research Database (Denmark)

Lippert, Solvej; Berg, Kasper D; Høyer-Hansen, Gunilla

2016-01-01

AIM: Urokinase plasminogen activator receptor (uPAR) plays a central role during cancer invasion by facilitating pericellular proteolysis. We initiated the prospective 'Copenhagen uPAR Prostate Cancer' study to investigate the significance of uPAR levels in prostate cancer (PCa) patients. METHODS...

Three-Dimensional Imaging Using Microcomputed Tomography For Studying Gaharu Morphology

International Nuclear Information System (INIS)

Yazid, Khair'iah; Bin Awang, Mat Rasol; Mohamed, Abdul Aziz; Bin Hj Khalid, Mohd Ashhar; Masschaele, Bert; Abdullah, Mohd. Zaid; Saleh, Junita Mohamad

2010-01-01

To demonstrates the potential application of the high resolution X-ray micro-CT technique in the analysis of internal structure in Gaharu wood. Gaharu or internationally, Agar wood, is known for its fragrant resinous wood. The hardware device used in this study was an X-ray micro-CT scanner at Center of Tomography (UGCT), CT facility in Ghent University, Belgium. This technique allows the 3D investigation of the internal structure of the wood in a non-destructive way. Most of the data analysis was done with the software VG Studio Max and MATLAB. Here we present some preliminary results from three-dimensional images from a piece of high grade Gaharu. Micro-CT images of the specimens were obtained at 7 μm resolution. Besides a clear distinction between pores and material, some bright white areas occur in the reconstruction images. Not only the volume visualization is helpful, morphological parameters of open-pores and dark resins are calculated from these 3D data set. The micro-CT technique is a valid support for evaluating the pores structure and resin distribution in Gaharu.

Recombination in the human Pseudoautosomal region PAR1.

Directory of Open Access Journals (Sweden)

Anjali G Hinch

2014-07-01

Full Text Available The pseudoautosomal region (PAR is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this obligatory crossover occurs remains unknown, as does the fine-scale positioning of crossovers across this region. Recent research in mice has suggested that crossovers in PAR may be mediated independently of the protein PRDM9, which localises virtually all crossovers in the autosomes. To investigate recombination in this region, we construct the most fine-scale genetic map containing directly observed crossovers to date using African-American pedigrees. We leverage recombination rates inferred from the breakdown of linkage disequilibrium in human populations and investigate the signatures of DNA evolution due to recombination. Further, we identify direct PRDM9 binding sites using ChIP-seq in human cells. Using these independent lines of evidence, we show that, in contrast with mouse, PRDM9 does localise peaks of recombination in the human PAR1. We find that recombination is a far more rapid and intense driver of sequence evolution in PAR1 than it is on the autosomes. We also show that PAR1 hotspot activities differ significantly among human populations. Finally, we find evidence that PAR1 hotspot positions have changed between human and chimpanzee, with no evidence of sharing among the hottest hotspots. We anticipate that the genetic maps built and validated in this work will aid research on this vital and fascinating region of the genome.

Plasma suPAR is lowered by smoking cessation

DEFF Research Database (Denmark)

Eugen-Olsen, Jesper; Ladelund, Steen; Sørensen, Lars Tue

2016-01-01

BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR) is a stable inflammatory biomarker. In patients, suPAR is a marker of disease presence, severity and prognosis. In the general population, suPAR is predictive of disease development, such as diabetes and cardiovascular disease a...

Imaging tissues for biomedical research using the high-resolution micro-tomography system nanotom® m

Science.gov (United States)

Deyhle, Hans; Schulz, Georg; Khimchenko, Anna; Bikis, Christos; Hieber, Simone E.; Jaquiery, Claude; Kunz, Christoph; Müller-Gerbl, Magdalena; Höchel, Sebastian; Saxer, Till; Stalder, Anja K.; Ilgenstein, Bernd; Beckmann, Felix; Thalmann, Peter; Buscema, Marzia; Rohr, Nadja; Holme, Margaret N.; Müller, Bert

2016-10-01

Micro computed tomography (mCT) is well established in virtually all fields of biomedical research, allowing for the non-destructive volumetric visualization of tissue morphology. A variety of specimens can be investigated, ranging from soft to hard tissue to engineered structures like scaffolds. Similarly, the size of the objects of interest ranges from a fraction of a millimeter to several tens of centimeters. While synchrotron radiation-based μCT still offers unrivaled data quality, the ever-improving technology of cathodic tube-based machines offers a valuable and more accessible alternative. The Biomaterials Science Center of the University of Basel operates a nanotomOR m (phoenix|x-ray, GE Sensing and Inspection Technologies GmbH, Wunstorf, Germany), with a 180 kV source and a minimal spot size of about 0.9 μm. Through the adjustable focus-specimen and focus-detector distances, the effective pixel size can be adjusted from below 500 nm to about 80 μm. On the high-resolution side, it is for example possible to visualize the tubular network in sub-millimeter thin dentin specimens. It is then possible to locally extract parameters such as tubule diameter, density, or alignment, giving information on cell movements during tooth formation. On the other side, with a horizontal shift of the 3,072 pixels x 2,400 pixels detector, specimens up to 35 cm in diameter can be scanned. It is possible, for example, to scan an entire human knee, albeit with inferior resolution. Lab source μCT machines are thus a powerful and flexible tool for the advancement of biomedical research, and a valuable and more accessible alternative to synchrotron radiation facilities.

Morphometric analysis - Cone beam computed tomography to predict bone quality and quantity.

Science.gov (United States)

Hohlweg-Majert, B; Metzger, M C; Kummer, T; Schulze, D

2011-07-01

Modified quantitative computed tomography is a method used to predict bone quality and quantify the bone mass of the jaw. The aim of this study was to determine whether bone quantity or quality was detected by cone beam computed tomography (CBCT) combined with image analysis. MATERIALS AND PROCEDURES: Different measurements recorded on two phantoms (Siemens phantom, Comac phantom) were evaluated on images taken with the Somatom VolumeZoom (Siemens Medical Solutions, Erlangen, Germany) and the NewTom 9000 (NIM s.r.l., Verona, Italy) in order to calculate a calibration curve. The spatial relationships of six sample cylinders and the repositioning from four pig skull halves relative to adjacent defined anatomical structures were assessed by means of three-dimensional visualization software. The calibration curves for computer tomography (CT) and cone beam computer tomography (CBCT) using the Siemens phantom showed linear correlation in both modalities between the Hounsfield Units (HU) and bone morphology. A correction factor for CBCT was calculated. Exact information about the micromorphology of the bone cylinders was only available using of micro computer tomography. Cone-beam computer tomography is a suitable choice for analysing bone mass, but, it does not give any information about bone quality. 2010 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

UGCT: New X-ray radiography and tomography facility

International Nuclear Information System (INIS)

Masschaele, B.C.; Cnudde, V.; Dierick, M.; Jacobs, P.; Hoorebeke, L. van; Vlassenbroeck, J.

2007-01-01

The UGCT (University Gent Computer Tomography) facility, a cooperation between the Radiation Physics research group and the Sedimentary Geology and Engineering Geology research group is a new CT facility providing a large range of scanning possibilities. Formerly a Skyscan 1072 was used to perform X-ray micro-CT scans at the UGCT facility and although this is a very powerful instrument, there were needs for a higher resolution and more flexibility. Therefore, the UCGT facility started the construction of a multidisciplinary micro-CT scanner inside a shielded room with a maximum flexibility of the set-up. The X-ray tube of this high-resolution CT scanner is a state-of-the-art open-type device with dual head: one head for high power micro-CT and one for sub-micro- or also called nano-CT. An important advantage of this scanner is that different detectors can be used to optimize the scanning conditions of the objects under investigation. The entire set-up is built on a large optical table to obtain the highest possible stability. Due to the flexible set-up and the powerful CT reconstruction software 'Octopus', it is possible to obtain the highest quality and the best signal-to-noise of the reconstructed images for each type of sample

UGCT: New X-ray radiography and tomography facility

Energy Technology Data Exchange (ETDEWEB)

Masschaele, B.C. [Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium)], E-mail: bert.masschaele@ugent.be; Cnudde, V. [Department of Geology and Soil Science, Ghent University, Krijgslaan 281, B-9000 Gent (Belgium); Dierick, M. [Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium); Jacobs, P. [Department of Geology and Soil Science, Ghent University, Krijgslaan 281, B-9000 Gent (Belgium); Hoorebeke, L. van; Vlassenbroeck, J. [Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium)

2007-09-21

The UGCT (University Gent Computer Tomography) facility, a cooperation between the Radiation Physics research group and the Sedimentary Geology and Engineering Geology research group is a new CT facility providing a large range of scanning possibilities. Formerly a Skyscan 1072 was used to perform X-ray micro-CT scans at the UGCT facility and although this is a very powerful instrument, there were needs for a higher resolution and more flexibility. Therefore, the UCGT facility started the construction of a multidisciplinary micro-CT scanner inside a shielded room with a maximum flexibility of the set-up. The X-ray tube of this high-resolution CT scanner is a state-of-the-art open-type device with dual head: one head for high power micro-CT and one for sub-micro- or also called nano-CT. An important advantage of this scanner is that different detectors can be used to optimize the scanning conditions of the objects under investigation. The entire set-up is built on a large optical table to obtain the highest possible stability. Due to the flexible set-up and the powerful CT reconstruction software 'Octopus', it is possible to obtain the highest quality and the best signal-to-noise of the reconstructed images for each type of sample.

Nondestructive Analysis of Astromaterials by Micro-CT and Micro-XRF Analysis for PET Examination

Science.gov (United States)

Zeigler, R. A.; Righter, K.; Allen, C. C.

2013-01-01

An integral part of any sample return mission is the initial description and classification of returned samples by the preliminary examination team (PET). The goal of the PET is to characterize and classify returned samples and make this information available to the larger research community who then conduct more in-depth studies on the samples. The PET tries to minimize the impact their work has on the sample suite, which has in the past limited the PET work to largely visual, nonquantitative measurements (e.g., optical microscopy). More modern techniques can also be utilized by a PET to nondestructively characterize astromaterials in much more rigorous way. Here we discuss our recent investigations into the applications of micro-CT and micro-XRF analyses with Apollo samples and ANSMET meteorites and assess the usefulness of these techniques in future PET. Results: The application of micro computerized tomography (micro-CT) to astromaterials is not a new concept. The technique involves scanning samples with high-energy x-rays and constructing 3-dimensional images of the density of materials within the sample. The technique can routinely measure large samples (up to approx. 2700 cu cm) with a small individual voxel size (approx. 30 cu m), and has the sensitivity to distinguish the major rock forming minerals and identify clast populations within brecciated samples. We have recently run a test sample of a terrestrial breccia with a carbonate matrix and multiple igneous clast lithologies. The test results are promising and we will soon analyze a approx. 600 g piece of Apollo sample 14321 to map out the clast population within the sample. Benchtop micro x-ray fluorescence (micro-XRF) instruments can rapidly scan large areas (approx. 100 sq cm) with a small pixel size (approx. 25 microns) and measure the (semi) quantitative composition of largely unprepared surfaces for all elements between Be and U, often with sensitivity on the order of a approx. 100 ppm. Our recent

The inflammatory marker suPAR after cardiac arrest

DEFF Research Database (Denmark)

Rundgren, Malin; Lyngbaek, Stig; Fisker, Helle

2015-01-01

. This pilot study aimed at investigating suPAR levels in relation to outcome after CA and mild induced hypothermia. METHODS: suPAR levels were measured at 6, 36, and 72 hours in patients treated with hypothermia after CA. suPAR levels were analyzed in relation to survival after 6 months. Receiver operating...

Bone quality evaluation at dental implant site using multislice CT, micro-CT, and cone beam CT.

Science.gov (United States)

Parsa, Azin; Ibrahim, Norliza; Hassan, Bassam; van der Stelt, Paul; Wismeijer, Daniel

2015-01-01

The first purpose of this study was to analyze the correlation between bone volume fraction (BV/TV) and calibrated radiographic bone density Hounsfield units (HU) in human jaws, derived from micro-CT and multislice computed tomography (MSCT), respectively. The second aim was to assess the accuracy of cone beam computed tomography (CBCT) in evaluating trabecular bone density and microstructure using MSCT and micro-CT, respectively, as reference gold standards. Twenty partially edentulous human mandibular cadavers were scanned by three types of CT modalities: MSCT (Philips, Best, the Netherlands), CBCT (3D Accuitomo 170, J Morita, Kyoto, Japan), and micro-CT (SkyScan 1173, Kontich, Belgium). Image analysis was performed using Amira (v4.1, Visage Imaging Inc., Carlsbad, CA, USA), 3Diagnosis (v5.3.1, 3diemme, Cantu, Italy), Geomagic (studio(®) 2012, Morrisville, NC, USA), and CTAn (v1.11, SkyScan). MSCT, CBCT, and micro-CT scans of each mandible were matched to select the exact region of interest (ROI). MSCT HU, micro-CT BV/TV, and CBCT gray value and bone volume fraction of each ROI were derived. Statistical analysis was performed to assess the correlations between corresponding measurement parameters. Strong correlations were observed between CBCT and MSCT density (r = 0.89) and between CBCT and micro-CT BV/TV measurements (r = 0.82). Excellent correlation was observed between MSCT HU and micro-CT BV/TV (r = 0.91). However, significant differences were found between all comparisons pairs (P micro-CT BV/TV (P = 0.147). An excellent correlation exists between bone volume fraction and bone density as assessed on micro-CT and MSCT, respectively. This suggests that bone density measurements could be used to estimate bone microstructural parameters. A strong correlation also was found between CBCT gray values and BV/TV and their gold standards, suggesting the potential of this modality in bone quality assessment at implant site. © 2013 John Wiley & Sons A/S. Published by

Micro-structural integrity of dental enamel subjected to two tooth whitening regimes.

Science.gov (United States)

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.

Development of a novel micro pattern gaseous detector for cosmic ray muon tomography

Energy Technology Data Exchange (ETDEWEB)

Biglietti, M. [INFN Sezione di Roma Tre, Rome (Italy); Canale, V. [Università di Napoli Federico II, Naples (Italy); INFN Sezione di Napoli, Naples (Italy); Franchino, S. [CERN, Geneva (Switzerland); Iengo, P. [INFN Sezione di Napoli, Naples (Italy); CERN, Geneva (Switzerland); Iodice, M. [INFN Sezione di Roma Tre, Rome (Italy); Petrucci, F., E-mail: petrucci@roma3.infn.it [INFN Sezione di Roma Tre, Rome (Italy); Università Roma Tre, Rome (Italy)

2016-07-11

We propose a novel detector (Thick Groove Detector, TGD) designed for cosmic ray tomography with a spatial resolution of ~500 μm, trying to keep the construction procedure as simple as possible and to reduce the operating costs. The TGD belongs to the category of MPGDs with an amplification region less than 1 mm wide formed by alternate anode/cathode microstrips layers at different heights. A first 10×10 cm{sup 2} prototype has been built, divided in four sections with different test geometries. We present the construction procedure and the first results in terms of gain and stability. Preliminary studies with cosmic rays are also reported. - Highlights: • A new MPGD detector designed for cosmic ray tomography is presented. • With respect to existing detectors, the construction procedure is simpler and operating costs are lower. • Construction procedures and preliminary performance are shown.

La erosión y sus implicaciones en la morfología de la micro cuenca del Igarapé Apeú, Estado do Pará, Brasil

Directory of Open Access Journals (Sweden)

Odete Cardoso de Oliveira Santos

2007-01-01

Full Text Available Las aguas de los canales que componen la micro cuenca del canal Apeú, ubicada en el nordeste del estado del Pará, en tierras de los municipios de Castanhal (70%, Inhangapí (10% y Santa Isabel do Pará (20%, son muy aprovechadas por los ribereños y pequeños campesinos. Por eso, en esta investigación se muestra que la erosión acelerada por las actividades antrópicas contribuye a los cambios de la morfología de  los  canales  fluviales  que  componen  la  microcuenca.  Para  medir  la  erosión  en  pendiente  se  empleó  la metodología de las estacas; para la erosión marginal en los canales se utilizó la metodología de los Pinos y de las Estacas. Los análisis fisicoquímicas de los sedimentos de los barrancos y del fondo de los canales fueron determinados por las técnicas descriptas por Guimarães et al. (1970, EMBRAPA (1997 y  Silva (1999. La profundidad de los canales se midió usando el molinete en vado, en el momento de las mediciones de los caudales en las secciones transversales de los canales. De acuerdo con los resultados, la pérdida de suelo por la erosión de la pendiente llegó a 74,02 m en el periodo de octubre de 2002 a julio de 2003. El canal Apeú, el principal de la microcuenca, en la hacienda Morro Verde abandonó su lecho normal por espacio de 50 metros, a causa de los sedimentos provenientes de surcos, zanjas y barrancos formados en el interior de la hacienda mencionada. En ese mismo canal, en el periodo menos lluvioso, en la villa agrícola de Macapazinho, en la mitad del lecho, el nivel de las aguas alcanzó  0,5 m; en el periodo lluvioso llegó a 3,0 m. En los canales predomina la carga del lecho.

Recent micro-CT scanner developments at UGCT

Energy Technology Data Exchange (ETDEWEB)

Dierick, Manuel, E-mail: Manuel.Dierick@UGent.be [UGCT-Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent (Belgium); XRE, X-Ray Engineering bvba, De Pintelaan 111, 9000 Ghent (Belgium); Van Loo, Denis, E-mail: info@XRE.be [XRE, X-Ray Engineering bvba, De Pintelaan 111, 9000 Ghent (Belgium); Masschaele, Bert [UGCT-Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent (Belgium); XRE, X-Ray Engineering bvba, De Pintelaan 111, 9000 Ghent (Belgium); Van den Bulcke, Jan [UGCT-Woodlab-UGent, Department of Forest and Water Management, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent (Belgium); Van Acker, Joris, E-mail: Joris.VanAcker@UGent.be [UGCT-Woodlab-UGent, Department of Forest and Water Management, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent (Belgium); Cnudde, Veerle, E-mail: Veerle.Cnudde@UGent.be [UGCT-SGIG, Department of Geology and Soil Science, Faculty of Sciences, Ghent University, Krijgslaan 281, S8, 9000 Ghent (Belgium); Van Hoorebeke, Luc, E-mail: Luc.VanHoorebeke@UGent.be [UGCT-Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent (Belgium)

2014-04-01

This paper describes two X-ray micro-CT scanners which were recently developed to extend the experimental possibilities of microtomography research at the Centre for X-ray Tomography ( (www.ugct.ugent.be)) of the Ghent University (Belgium). The first scanner, called Nanowood, is a wide-range CT scanner with two X-ray sources (160 kV{sub max}) and two detectors, resolving features down to 0.4 μm in small samples, but allowing samples up to 35 cm to be scanned. This is a sample size range of 3 orders of magnitude, making this scanner well suited for imaging multi-scale materials such as wood, stone, etc. Besides the traditional cone-beam acquisition, Nanowood supports helical acquisition, and it can generate images with significant phase-contrast contributions. The second scanner, known as the Environmental micro-CT scanner (EMCT), is a gantry based micro-CT scanner with variable magnification for scanning objects which are not easy to rotate in a standard micro-CT scanner, for example because they are physically connected to external experimental hardware such as sensor wiring, tubing or others. This scanner resolves 5 μm features, covers a field-of-view of about 12 cm wide with an 80 cm vertical travel range. Both scanners will be extensively described and characterized, and their potential will be demonstrated with some key application results.

Recent micro-CT scanner developments at UGCT

International Nuclear Information System (INIS)

Dierick, Manuel; Van Loo, Denis; Masschaele, Bert; Van den Bulcke, Jan; Van Acker, Joris; Cnudde, Veerle; Van Hoorebeke, Luc

2014-01-01

This paper describes two X-ray micro-CT scanners which were recently developed to extend the experimental possibilities of microtomography research at the Centre for X-ray Tomography ( (www.ugct.ugent.be)) of the Ghent University (Belgium). The first scanner, called Nanowood, is a wide-range CT scanner with two X-ray sources (160 kV max ) and two detectors, resolving features down to 0.4 μm in small samples, but allowing samples up to 35 cm to be scanned. This is a sample size range of 3 orders of magnitude, making this scanner well suited for imaging multi-scale materials such as wood, stone, etc. Besides the traditional cone-beam acquisition, Nanowood supports helical acquisition, and it can generate images with significant phase-contrast contributions. The second scanner, known as the Environmental micro-CT scanner (EMCT), is a gantry based micro-CT scanner with variable magnification for scanning objects which are not easy to rotate in a standard micro-CT scanner, for example because they are physically connected to external experimental hardware such as sensor wiring, tubing or others. This scanner resolves 5 μm features, covers a field-of-view of about 12 cm wide with an 80 cm vertical travel range. Both scanners will be extensively described and characterized, and their potential will be demonstrated with some key application results

It's quicker "Par Avignon"!

CERN Multimedia

2005-01-01

For a few years, the CERN Library has been receiving books from the University of Hanover sent via Avignon, at least that's what it says on the envelope. Such a detour would mean that parcels were travelling 720 km more than the distance separating Geneva and Hanover, which would be a very strange state of affairs. The explanation lies in a spelling mistake. The sender has been stamping parcels with a stamp that says "Par Avignon prioritaire" (first-class via Avignon) instead of "Par Avion prioritaire" (First Class Air Mail), a source of much amusement to the librarians!

Serum suPAR in patients with FSGS: trash or treasure?

Science.gov (United States)

Maas, Rutger J H; Deegens, Jeroen K J; Wetzels, Jack F M

2013-07-01

The urokinase-type plasminogen activator receptor (uPAR) has important functions in cell migration. uPAR can be shed from the cell membrane resulting in soluble uPAR (suPAR). Further cleavage gives rise to shorter fragments with largely unknown functions. Recent studies have demonstrated that both overexpression of uPAR on podocytes and the administration of suPAR cause proteinuria in mice. The common pathogenic mechanism involves the activation of podocyte β3-integrin. Increased activation of β3-integrin is also observed in patients with focal and segmental glomerulosclerosis (FSGS). These observations form the basis for the hypothesis that suPAR may be the circulating factor causing FSGS. A recent study fosters this idea by demonstrating increased suPAR levels in the serum of patients with FSGS and reporting an association with recurrence after transplantation and response to plasmapheresis. However, this study was heavily biased, and subsequent studies have given conflicting results. Although the experimental work is very suggestive, at present there is no proof that any known human suPAR fragment causes FSGS in humans. We therefore suggest that the measurement of suPAR using currently available assays has absolutely no value at the present time in decision-making in routine clinical practice.

Proteinase-Activated Receptor 1 (PAR1 regulates leukemic stem cell functions.

Directory of Open Access Journals (Sweden)

Nicole Bäumer

Full Text Available External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

Proteinase-Activated Receptor 1 (PAR1) regulates leukemic stem cell functions.

Science.gov (United States)

Bäumer, Nicole; Krause, Annika; Köhler, Gabriele; Lettermann, Stephanie; Evers, Georg; Hascher, Antje; Bäumer, Sebastian; Berdel, Wolfgang E; Müller-Tidow, Carsten; Tickenbrock, Lara

2014-01-01

External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.

Serum suPAR in patients with FSGS: trash or treasure?

NARCIS (Netherlands)

Maas, R.J.H.; Deegens, J.K.J.; Wetzels, J.F.M.

2013-01-01

The urokinase-type plasminogen activator receptor (uPAR) has important functions in cell migration. uPAR can be shed from the cell membrane resulting in soluble uPAR (suPAR). Further cleavage gives rise to shorter fragments with largely unknown functions. Recent studies have demonstrated that both

Accouchement par forceps: indications et pronostic materno-foetal ...

African Journals Online (AJOL)

L'accouchement par voie basse, peut être parfois compromis par des facteurs maternels, foetaux ou materno-foetaux nécessitant des moyens thérapeutiques comme le forceps pour achever l'accouchement par voie naturelle. Le forceps, une méthode qui n'est pas sans risque pour la mère et le nouveau-né. Nous avons ...

Analysing Structure Dynamics in Arable Soils using X-ray Micro-Tomography

Science.gov (United States)

Schlüter, S.; Weller, U.; Vogel, H.-J.

2009-04-01

Structure is a dynamic property of soil. It interacts with many biotic and abiotic features and controls various soil functions. We analyzed soil structure within different plots of the ''Static Fertilisation Experiment'' at the agricultural research station in Bad Lauchstaedt (Germany) using X-ray micro tomography. The aim was to investigate in how far different levels of organic carbon, increased microbial activity and enhanced plant growth affects structural properties of an arable soil. Since 106 years one plot has experienced a constant application of farmyard manure and fertilisers, whereas the other has never been fertilised in this period. Intact soil cores from the chernozem soil at the two plots were taken from a depth of 5 to 15 cm (Ap-horizon) and 35 to 45 cm (Ah-horizon) to analyse structural changes with depth and in two different seasons (spring and summer) to investigate structure dynamics. The pore structure was analysed by quantifying the mean geometrical and topological characteristics of the pore network as a function of pore size. This was done by a combination of Minkowski functionals and morphological size distibution. For small structural features close to the image resolution the results clearly depend on the applied filtering technique and segmentation thresholds. Therefore the application of different image enhancement techniques is discussed. Furthermore, a new method for an automated determination of grey value thesholds for the segmentation of CT-images into pore space and solid is developed and evaluated. We highlight the relevance of image resolution for structure analysis. Results of the structure analysis reveal that the spring samples of the ploughed layer (Ap-horizon) from the fertilised plot have significantly higher macroporosities (P connectivity of the pore network is better in the fertilised plot and the pore size distribution was found to be different, too. The differences in porosity and pore connectivity increase from

Detection of bladder tumors using optical coherence tomography

Science.gov (United States)

Pan, Yingtian; Xie, Tuqiang; Wang, Zhenguo

2004-07-01

This paper summarizes the engineering development of our lab for endoscopic optical coherence tomography toward the ultimate goal to image bladder micro architecture and to diagnose bladder cancers. To test the utility and potential limitations of OCT setups for bladder tumor diagnosis, we used a rat bladder cancer model to track the morphological changes following tumor growth. Image results are presented, suggesting that OCT is able to differentiate cancerous lesions from inflammatory lesions based on OCT characterizations of epithelial thickness and backscattering changes of bladder tissue.

Quantitative pre-clinical screening of therapeutics for joint diseases using contrast enhanced micro-computed tomography.

Science.gov (United States)

Willett, N J; Thote, T; Hart, M; Moran, S; Guldberg, R E; Kamath, R V

2016-09-01

The development of effective therapies for cartilage protection has been limited by a lack of efficient quantitative cartilage imaging modalities in pre-clinical in vivo models. Our objectives were two-fold: first, to validate a new contrast-enhanced 3D imaging analysis technique, equilibrium partitioning of an ionic contrast agent-micro computed tomography (EPIC-μCT), in a rat medial meniscal transection (MMT) osteoarthritis (OA) model; and second, to quantitatively assess the sensitivity of EPIC-μCT to detect the effects of matrix metalloproteinase inhibitor (MMPi) therapy on cartilage degeneration. Rats underwent MMT surgery and tissues were harvested at 1, 2, and 3 weeks post-surgery or rats received an MMPi or vehicle treatment and tissues harvested 3 weeks post-surgery. Parameters of disease progression were evaluated using histopathology and EPIC-μCT. Correlations and power analyses were performed to compare the techniques. EPIC-μCT was shown to provide simultaneous 3D quantification of multiple parameters, including cartilage degeneration and osteophyte formation. In MMT animals treated with MMPi, OA progression was attenuated, as measured by 3D parameters such as lesion volume and osteophyte size. A post-hoc power analysis showed that 3D parameters for EPIC-μCT were more sensitive than 2D parameters requiring fewer animals to detect a therapeutic effect of MMPi. 2D parameters were comparable between EPIC-μCT and histopathology. This study demonstrated that EPIC-μCT has high sensitivity to provide 3D structural and compositional measurements of cartilage and bone in the joint. EPIC-μCT can be used in combination with histology to provide a comprehensive analysis to screen new potential therapies. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Non-destructive, high-content analysis of wheat grain traits using X-ray micro computed tomography

Directory of Open Access Journals (Sweden)

Nathan Hughes

2017-11-01

Full Text Available Abstract Background Wheat is one of the most widely grown crop in temperate climates for food and animal feed. In order to meet the demands of the predicted population increase in an ever-changing climate, wheat production needs to dramatically increase. Spike and grain traits are critical determinants of final yield and grain uniformity a commercially desired trait, but their analysis is laborious and often requires destructive harvest. One of the current challenges is to develop an accurate, non-destructive method for spike and grain trait analysis capable of handling large populations. Results In this study we describe the development of a robust method for the accurate extraction and measurement of spike and grain morphometric parameters from images acquired by X-ray micro-computed tomography (μCT. The image analysis pipeline developed automatically identifies plant material of interest in μCT images, performs image analysis, and extracts morphometric data. As a proof of principle, this integrated methodology was used to analyse the spikes from a population of wheat plants subjected to high temperatures under two different water regimes. Temperature has a negative effect on spike height and grain number with the middle of the spike being the most affected region. The data also confirmed that increased grain volume was correlated with the decrease in grain number under mild stress. Conclusions Being able to quickly measure plant phenotypes in a non-destructive manner is crucial to advance our understanding of gene function and the effects of the environment. We report on the development of an image analysis pipeline capable of accurately and reliably extracting spike and grain traits from crops without the loss of positional information. This methodology was applied to the analysis of wheat spikes can be readily applied to other economically important crop species.

Dimensional quality control of Ti-Ni dental file by optical coordinate metrology and computed tomography

DEFF Research Database (Denmark)

Yagüe-Fabra, J.A.; Tosello, Guido; Ontiveros, S.

2014-01-01

Endodontic dental files usually present complex 3D geometries, which make the complete measurement of the component very challenging with conventional micro metrology tools. Computed Tomography (CT) can represent a suitable alternative solution to micro metrology tools based on optical and tactile...... techniques. However, the establishment of CT systems traceability when measuring 3D complex geometries is still an open issue. In this work, to verify the quality of the CT dimensional measurements, the dental file has been measured both with a μCT system and an optical CMM (OCMM). The uncertainty...

Nano-computed tomography. Technique and applications; Nanocomputertomografie. Technik und Applikationen

Energy Technology Data Exchange (ETDEWEB)

Kampschulte, M.; Sender, J.; Litzlbauer, H.D.; Althoehn, U.; Schwab, J.D.; Alejandre-Lafont, E.; Martels, G.; Krombach, G.A. [University Hospital Giessen (Germany). Dept. of Diagnostic and Interventional Radiology; Langheinirch, A.C. [BG Trauma Hospital Frankfurt/Main (Germany). Dept. of Diagnostic and Interventional Radiology

2016-02-15

Nano-computed tomography (nano-CT) is an emerging, high-resolution cross-sectional imaging technique and represents a technical advancement of the established micro-CT technology. Based on the application of a transmission target X-ray tube, the focal spot size can be decreased down to diameters less than 400 nanometers (nm). Together with specific detectors and examination protocols, a superior spatial resolution up to 400 nm (10 % MTF) can be achieved, thereby exceeding the resolution capacity of typical micro-CT systems. The technical concept of nano-CT imaging as well as the basics of specimen preparation are demonstrated exemplarily. Characteristics of atherosclerotic plaques (intraplaque hemorrhage and calcifications) in a murine model of atherosclerosis (ApoE{sub (-/-)}/LDLR{sub (-/-)} double knockout mouse) are demonstrated in the context of superior spatial resolution in comparison to micro-CT. Furthermore, this article presents the application of nano-CT for imaging cerebral microcirculation (murine), lung structures (porcine), and trabecular microstructure (ovine) in contrast to micro-CT imaging. This review shows the potential of nano-CT as a radiological method in biomedical basic research and discusses the application of experimental, high resolution CT techniques in consideration of other high resolution cross-sectional imaging techniques.

Clinical outcomes of pars plicata anterior vitrectomy: 2-year results

Directory of Open Access Journals (Sweden)

Priya Narang

2015-01-01

Full Text Available Purpose: To demonstrate the safety and outcome of a surgical approach that uses pars plicata site for anterior vitrectomy during phacoemulsification procedure complicated by posterior capsule rupture and residual cortical matter. Design: Single center, retrospective, interventional, noncomparative study. Materials and Methods: Medical records of a consecutive series of 35 eyes of 35 patients who underwent pars plicata anterior vitrectomy (PPAV were reviewed. The main outcome measures were corrected and uncorrected distance visual acuity (CDVA, UDVA, early and late postoperative complications and intraocular pressure (IOP. Ultrasound biomicroscopic (UBM evaluation of sclerotomy site and spectral domain optical coherence tomography analysis for central macular thickness (CMT was performed. The final visual outcome at 2 years was evaluated. Results: At 2 years follow-up, the mean postoperative UDVA (logarithm of the minimum angle of resolution [logMAR] and CDVA (logMAR was 0.49 ± 0.26 and 0.19 ± 0.14, respectively. There was no significant change in the IOP (P = 0.061 and the mean CMT at 2 years was 192.5 ± 5.54 mm. The postoperative UBM image of the sclerotomy site at 8 weeks demonstrated a clear wound without any vitreous adhesion or incarceration. Intraoperative hyphema was seen in 1 (2.8% case and postoperative uveitis was seen in 2 (5.7% cases, which resolved with medications. No case of an iatrogenic retinal break or retinal detachment was reported. Conclusions: PPAV enables a closed chamber approach, allows thorough cleanup of vitreous in the pupillary plane and anterior chamber and affords better access to the subincisional and retropupillary cortical remnant with a significant visual outcome and an acceptable complication rate.

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

Science.gov (United States)

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.

MicroPET imaging and transgenic models: a blueprint for Alzheimer's disease clinical research.

Science.gov (United States)

Zimmer, Eduardo R; Parent, Maxime J; Cuello, A Claudio; Gauthier, Serge; Rosa-Neto, Pedro

2014-11-01

Over the past decades, developments in neuroimaging have significantly contributed to the understanding of Alzheimer's disease (AD) pathophysiology. Specifically, positron emission tomography (PET) imaging agents targeting amyloid deposition have provided unprecedented opportunities for refining in vivo diagnosis, monitoring disease propagation, and advancing AD clinical trials. Furthermore, the use of a miniaturized version of PET (microPET) in transgenic (Tg) animals has been a successful strategy for accelerating the development of novel radiopharmaceuticals. However, advanced applications of microPET focusing on the longitudinal propagation of AD pathophysiology or therapeutic strategies remain in their infancy. This review highlights what we have learned from microPET imaging in Tg models displaying amyloid and tau pathology, and anticipates cutting-edge applications with high translational value to clinical research. Copyright © 2014 Elsevier Ltd. All rights reserved.

ParSel: Parallel Selection of Micro-RNAs for Survival Classification in Cancers.

Science.gov (United States)

Sinha, Debajyoti; Sengupta, Debarka; Bandyopadhyay, Sanghamitra

2017-07-01

It is known that tumor micro-RNAs (miRNA) can define patient survival and treatment response. We present a framework to identify miRNAs which are predictive of cancer survival. The framework attempts to rank the miRNAs by exploring their collaborative role in gene regulation. Our approach tests a significantly large number of combinatorial cases leveraging parallel computation. We carefully avoided parametric assumptions involved in evaluations of miRNA expressions but used rigorous statistical computation to assign an importance score to a miRNA. Experimental results on three cancer types namely, KIRC, OV and GBM verify that the top ranked miRNAs obtained using the proposed framework produce better classification accuracy as compared to some best practice variable selection methods. Some of these top ranked miRNA are also known to be associated with related diseases. © 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Energy Technology Data Exchange (ETDEWEB)

Alvarenga de Moura Meneses, Anderson, E-mail: ameneses@ieee.org [Radiological Sciences Laboratory, Rio de Janeiro State University, Rua Sao Francisco Xavier 524, CEP 20550-900, RJ (Brazil); Giusti, Alessandro [IDSIA (Dalle Molle Institute for Artificial Intelligence), University of Lugano (Switzerland); Pereira de Almeida, Andre; Parreira Nogueira, Liebert; Braz, Delson [Nuclear Engineering Program, Federal University of Rio de Janeiro, RJ (Brazil); Cely Barroso, Regina [Laboratory of Applied Physics on Biomedical Sciences, Physics Department, Rio de Janeiro State University, RJ (Brazil); Almeida, Carlos Eduardo de [Radiological Sciences Laboratory, Rio de Janeiro State University, Rua Sao Francisco Xavier 524, CEP 20550-900, RJ (Brazil)

2011-12-21

Synchrotron Radiation (SR) X-ray micro-Computed Tomography ({mu}CT) 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-{mu}CT 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-{mu}CT 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-{mu}CT 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.

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

International Nuclear Information System (INIS)

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

2011-01-01

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.

Biomechanical aspects of initial intraosseous stability and implant design: a quantitative micro-morphometric analysis.

Science.gov (United States)

Akça, Kivanç; Chang, Ting-Ling; Tekdemir, Ibrahim; Fanuscu, Mete I

2006-08-01

The objective of this biomechanical study was to explore the effect of bone micro-morphology on initial intraosseous stability of implants with different designs. Straumann and Astra Tech dental implants were placed into anterior and posterior regions of completely edentulous maxilla and mandible of a human cadaver. Experiments were undertaken to quantify initial implant stability and bone micro-morphology. Installation torque values (ITVs) and implant stability quotients (ISQs) were measured to determine initial intraosseous implant stability. For quantification of relative bone volume and micro-architecture, sectioned implant-bone and bone core specimens of each implant placement site were consecutively scanned and trabecular bone was analyzed in a micro-computed tomography (micro-CT) unit. Experimental outcomes were evaluated for correlations among implant designs, initial intraosseous implant stability and bone micro-structural parameters. ITVs correlated higher with bone volume fraction (BV/TV) than ISQs, at 88.1% and 68.9% levels, respectively. Correlations between ITVs and micro-morphometric parameters were significant at the 95% confidence level (Pimplant designs used were not significant at the 95% confidence level (P>0.05). Bone micro-morphology has a prevailing effect over implant design on intraosseus initial implant stability, and ITV is more sensitive in terms of revealing biomechanical properties at the bone-implant interface in comparison with ISQ.

Protease-Activated Receptor 4 (PAR4): A Promising Target for Antiplatelet Therapy.

Science.gov (United States)

Rwibasira Rudinga, Gamariel; Khan, Ghulam Jilany; Kong, Yi

2018-02-14

Cardiovascular diseases (CVDs) are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs), including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR). Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

Imaging micro-glial/macrophage activation in spinal cords of experimental autoimmune encephalomyelitis rats by Positron Emission Tomography using the mitochondrial 18 kDa translocator protein radioligand [18F]DPA-714

International Nuclear Information System (INIS)

Abourbeh, Galith; Theze, Benoit; Dubois, Albertine; Tavitian, Bertrand; Boisgard, Raphael; Maroy, Renaud; Brulon, Vincent; Fontyn, Yoann; Dolle, Frederic

2012-01-01

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS. Activated micro-glia/macrophages play a key role in the immuno-pathogenesis of MS and its corresponding animal models, experimental autoimmune encephalomyelitis (EAE). Micro-glia activation begins at early stages of the disease and is associated with elevated expression of the 18 kDa mitochondrial translocator protein (TSPO). Thus, positron emission tomography (PET) imaging of micro-glial activation using TSPO-specific radioligands could be valuable for monitoring disease-associated neuro-inflammatory processes. EAE was induced in rats using a fragment of myelin basic protein, yielding acute clinical disease that reflects extensive spinal cord inflammation. Enhanced TSPO expression in spinal cords of EAE rats versus those of controls was confirmed by Western blot and immunohistochemistry. Biodistribution studies in control and EAE rats were performed using the TSPO radioligand [ 18 F]DPA-714 [N,N-diethyl-2-(2-(4-(2-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5- a]pyrimidin-3-yl)acetamide]. At 1 h after injection, almost fivefold higher levels of [ 18 F]DPA-714 were measured in spinal cords of EAE rats versus controls. The specific binding of [ 18 F]DPA-714 to TSPO in spinal cords was confirmed in competition studies, using unlabeled (R,S)-PK11195 [(R,S)-N-methyl-N-(1-methylpropyl)-1-(2-chlorophenyl) - isoquinoline-3-carboxamide)] or DPA-714 in excess. MicroPET studies affirm that this differential radioactivity uptake in spinal cords of EAE versus control rats could be detected and quantified. Using [ 18 F]DPA-714, neuro-inflammation in spinal cords of EAE-induced rats could be visualized by PET, offering a sensitive technique for monitoring neuro-inflammatory lesions in the CNS and particularly in the spinal cord. In addition to current MRI protocols, this approach could provide molecular images of neuro-inflammation for detection, monitoring, and research in MS. (authors)

Internal structures of scaffold-free 3D cell cultures visualized by synchrotron radiation-based micro-computed tomography

Science.gov (United States)

Saldamli, Belma; Herzen, Julia; Beckmann, Felix; Tübel, Jutta; Schauwecker, Johannes; Burgkart, Rainer; Jürgens, Philipp; Zeilhofer, Hans-Florian; Sader, Robert; Müller, Bert

2008-08-01

Recently the importance of the third dimension in cell biology has been better understood, resulting in a re-orientation towards three-dimensional (3D) cultivation. Yet adequate tools for their morphological characterization have to be established. Synchrotron radiation-based micro computed tomography (SRμCT) allows visualizing such biological systems with almost isotropic micrometer resolution, non-destructively. We have applied SRμCT for studying the internal morphology of human osteoblast-derived, scaffold-free 3D cultures, termed histoids. Primary human osteoblasts, isolated from femoral neck spongy bone, were grown as 2D culture in non-mineralizing osteogenic medium until a rather thick, multi-cellular membrane was formed. This delicate system was intentionally released to randomly fold itself. The folded cell cultures were grown to histoids of cubic milli- or centimeter size in various combinations of mineralizing and non-mineralizing osteogenic medium for a total period of minimum 56 weeks. The SRμCT-measurements were performed in the absorption contrast mode at the beamlines BW 2 and W 2 (HASYLAB at DESY, Hamburg, Germany), operated by the GKSS-Research Center. To investigate the entire volume of interest several scans were performed under identical conditions and registered to obtain one single dataset of each sample. The histoids grown under different conditions exhibit similar external morphology of globular or ovoid shape. The SRμCT-examination revealed the distinctly different morphological structures inside the histoids. One obtains details of the histoids that permit to identify and select the most promising slices for subsequent histological characterization.

Bone quality evaluation at dental implant site using multislice CT, micro-CT, and cone beam CT

NARCIS (Netherlands)

Parsa, A.; Ibrahim, N.; Hassan, B.; van der Stelt, P.; Wismeijer, D.

2015-01-01

Objectives The first purpose of this study was to analyze the correlation between bone volume fraction (BV/TV) and calibrated radiographic bone density Hounsfield units (HU) in human jaws, derived from micro-CT and multislice computed tomography (MSCT), respectively. The second aim was to assess the

PAR1 activation affects the neurotrophic properties of Schwann cells.

Science.gov (United States)

Pompili, Elena; Fabrizi, Cinzia; Somma, Francesca; Correani, Virginia; Maras, Bruno; Schininà, Maria Eugenia; Ciraci, Viviana; Artico, Marco; Fornai, Francesco; Fumagalli, Lorenzo

2017-03-01

Protease-activated receptor-1 (PAR1) is the prototypic member of a family of four G-protein-coupled receptors that signal in response to extracellular proteases. In the peripheral nervous system, the expression and/or the role of PARs are still poorly investigated. High PAR1 mRNA expression was found in the rat dorsal root ganglia and the signal intensity of PAR1 mRNA increased in response to sciatic nerve transection. In the sciatic nerve, functional PAR1 receptor was reported at the level of non-compacted Schwann cell myelin microvilli of the nodes of Ranvier. Schwann cells are the principal population of glial cells of the peripheral nervous system which myelinate axons playing an important role during axonal regeneration and remyelination. The present study was undertaken in order to determine if the activation of PAR1 affects the neurotrophic properties of Schwann cells. Our results suggest that the stimulation of PAR1 could potentiate the Schwann cell ability to favour nerve regeneration. In fact, the conditioned medium obtained from Schwann cell cultures challenged with a specific PAR1 activating peptide (PAR1 AP) displays increased neuroprotective and neurotrophic properties with respect to the culture medium from untreated Schwann cells. The proteomic analysis of secreted proteins in untreated and PAR1 AP-treated Schwann cells allowed the identification of factors differentially expressed in the two samples. Some of them (such as macrophage migration inhibitory factor, matrix metalloproteinase-2, decorin, syndecan 4, complement C1r subcomponent, angiogenic factor with G patch and FHA domains 1) appear to be transcriptionally regulated after PAR1 AP treatment as shown by RT-PCR. Copyright © 2017 Elsevier Inc. All rights reserved.

Protease-Activated Receptor 4 (PAR4: A Promising Target for Antiplatelet Therapy

Directory of Open Access Journals (Sweden)

Gamariel Rwibasira Rudinga

2018-02-01

Full Text Available Cardiovascular diseases (CVDs are currently among the leading causes of death worldwide. Platelet aggregation is a key cellular component of arterial thrombi and major cause of CVDs. Protease-activated receptors (PARs, including PAR1, PAR2, PAR3 and PAR4, fall within a subfamily of seven-transmembrane G-protein-coupled receptors (GPCR. Human platelets express PAR1 and PAR4, which contribute to the signaling transduction processes. In association with CVDs, PAR4 not only contributes to platelet activation but also is a modulator of cellular responses that serve as hallmarks of inflammation. Although several antiplatelet drugs are available on the market, they have many side effects that limit their use. Emerging evidence shows that PAR4 targeting is a safer strategy for preventing thrombosis and consequently may improve the overall cardiac safety profile. Our present review summarizes the PAR4 structural characteristics, activation mechanism, role in the pathophysiology of diseases and understanding the association of PAR4 targeting for improved cardiac protection. Conclusively, this review highlights the importance of PAR4 antagonists and its potential utility in different CVDs.

“Study of secondary hydriding at high temperature in zirconium based nuclear fuel cladding tubes by coupling information from neutron radiography/tomography, electron probe micro analysis, micro elastic recoil detection analysis and laser induced breakdown spectroscopy microprobe

Energy Technology Data Exchange (ETDEWEB)

Brachet, Jean-Christophe, E-mail: jean-christophe.brachet@cea.fr [DEN-Service de Recherches Métallurgiques Appliquées (SRMA), CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); Hamon, Didier; Le Saux, Matthieu [DEN-Service de Recherches Métallurgiques Appliquées (SRMA), CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); Vandenberghe, Valérie [DEN-Service de Recherches Métallurgiques Appliquées (SRMA), CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); DEN-Service d’Etudes Mécaniques et Thermiques (SEMT), CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); Toffolon-Masclet, Caroline; Rouesne, Elodie; Urvoy, Stéphane [DEN-Service de Recherches Métallurgiques Appliquées (SRMA), CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); Béchade, Jean-Luc [DEN-Service de Recherches Métallurgiques Appliquées (SRMA), CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); DEN-Service de Recherches de Métallurgie Physique (SRMP), CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); Raepsaet, Caroline [LEEL, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette (France); NIMBE, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette Cedex (France); and others

2017-05-15

This paper gives an overview of a multi-scale experimental study of the secondary hydriding phenomena that can occur in nuclear fuel cladding materials exposed to steam at high temperature (HT) after having burst (loss-of-coolant accident conditions). By coupling information from several facilities, including neutron radiography/tomography, electron probe micro analysis, micro elastic recoil detection analysis and micro laser induced breakdown spectroscopy, it was possible to map quantitatively, at different scales, the distribution of oxygen and hydrogen within M5™ clad segments having experienced ballooning and burst at HT followed by steam oxidation at 1100 and 1200 °C and final direct water quenching down to room temperature. The results were very reproducible and it was confirmed that internal oxidation and secondary hydriding at HT of a cladding after burst can lead to strong axial and azimuthal gradients of hydrogen and oxygen concentrations, reaching 3000–4000 wt ppm and 1.0–1.2 wt% respectively within the β phase layer for the investigated conditions. Consistent with thermodynamic and kinetics considerations, oxygen diffusion into the prior-β layer was enhanced in the regions highly enriched in hydrogen, where the α(O) phase layer is thinner and the prior-β layer thicker. Finally the induced post-quenching hardening of the prior-β layer was mainly related to the local oxygen enrichment. Hardening directly induced by hydrogen was much less significant. - Highlights: •More than 50% of the gaseous hydrogen produced by the inner clad oxidation absorbed and trapped into prior-β layer. •High hydrogen and oxygen local concentrations, up to 3000–4000 wt. ppm and 1.0–1.2 wt.% respectively, within the β phase. •Enhanced oxygen diffusion into hydrogen enriched prior-β layer, with locally thinner α(O) and thicker prior-β layers. •Post-quenching hardening of the prior-β structure mainly related to the (local) oxygen concentration. �

An electronic probe micro-analyser. A linear scan device; Microanalyseur a sonde electronique. Dispositif de balayage lineaire

Energy Technology Data Exchange (ETDEWEB)

Kirianenko, A; Maurice, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-07-01

The Castaing electronic probe micro-analyser makes possible static analysis at successive points. For two years this apparatus has been equipped by its constructor with an automatic device for surface scanning. In order to increase the micro-analyser's efficiency a 'linear' scan device has been incorporated making it possible to obtain semi-quantitative analyses very rapidly. (authors) [French] Le microanalyseur a sonde electronique de Castaing permet l'analyse statique en des points successifs. Depuis deux ans, cet appareil a ete equipe par son constructeur d'un dispositif de balayage automatique 'surface'. Afin d'augmenter l'efficacite du microanalyaeur, on a adapte un dispositif de balayage 'lineaire' qui permet d'obtenir tres rapidement des analyses semi-quantitative. (auteurs)

Pulmonary blood flow distribution measured by radionuclide computed tomography

International Nuclear Information System (INIS)

Maeda, H.; Itoh, H.; Ishii, Y.

1982-01-01

Distributions of pulmonary blood flow per unit lung volume were measured in sitting patients with a radionuclide computed tomography (RCT) by intravenously administered Tc-99m macroaggregates of human serum albumin (MAA). Four different types of distribution were distinguished, among which a group referred as type 2 had a three zonal blood flow distribution as previously reported (West and co-workers, 1964). The pulmonary arterial pressure (Pa) and the venous pressure (Pv) were determined in this group of distribution. These values showed satifactory agreements with the pulmonary artery pressure (Par) and the capillary wedged pressure (Pcw) measured by Swan-Ganz catheter in eighteen supine patients. Those good correlations enable to establish a noninvasive methodology for measurement of pulmonary vascular pressures

Vote par sondage uniforme incorruptible

OpenAIRE

Blanchard , Nicolas

2016-01-01

International audience; Introduit en 2012 par David Chaum, le vote par sondage uniforme (random-sample voting) est un protocole de vote basé sur un choix d'une sous-population représentative , permettant de limiter les coûts tout en ayant de nombreux avantages, principalement lorsqu'il est couplé a d'autres techniques comme ThreeBallot. Nous analysons un problème de corruptibilité potentielle où les votants peuvent vendre leur vote au plus offrant et proposons une variation du protocole reméd...

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

Science.gov (United States)

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.

The double par locus of virulence factor pB171: DNA segregation is correlated with oscillation of ParA

DEFF Research Database (Denmark)

Ebersbach, G; Gerdes, K; Charbon, Gitte Ebersbach

2001-01-01

Prokaryotic plasmids and chromosomes encode partitioning (par) loci that segregate DNA to daughter cells before cell division. Recent database analyses showed that almost all known par loci encode an ATPase and a DNA-binding protein, and one or more cis-acting regions where the proteins act. All...

Quality of root fillings performed with two root filling techniques. An in vitro study using micro-CT

DEFF Research Database (Denmark)

Møller, L; Wenzel, A; Wegge-Larsen, AM

2013-01-01

-section images from Micro-computed Tomography scans. Results. All root canal fillings had voids. Permutation test showed no statistically significant difference between the two root filling techniques in relation to presence of voids (p = 0.092). A statistically significant difference in obturation time between...

The role of pars flaccida in human middle ear sound transmission.

Science.gov (United States)

Aritomo, H; Goode, R L; Gonzalez, J

1988-04-01

The role of the pars flaccida in middle ear sound transmission was studied with the use of twelve otoscopically normal, fresh, human temporal bones. Peak-to-peak umbo displacement in response to a constant sound pressure level at the tympanic membrane was measured with a noncontacting video measuring system capable of repeatable measurements down to 0.2 micron. Measurements were made before and after pars flaccida modifications at 18 frequencies between 100 and 4000 Hz. Four pars flaccida modifications were studied: (1) acoustic insulation of the pars flaccida to the ear canal with a silicone rubber baffle, (2) stiffening the pars flaccida with cyanoacrylate cement, (3) decreasing the tension of the pars flaccida with a nonperforating incision, and (4) perforation of the pars flaccida. All of the modifications (except the perforation) had a minimal effect on umbo displacement; this seems to imply that the pars flaccida has a minor acoustic role in human beings.

Current radiography and tomography applications at Necsa and an envisaged upgrade towards a proposed South African national centre for radiography and tomography (SANCRAT)

Energy Technology Data Exchange (ETDEWEB)

Radebe, M.J.; De Beer, F.C. [Necsa - South African Nuclear Energy Corporation Limited, P. O.Box 582, Pretoria, 0001 (South Africa)

2008-07-01

An upgrade of the current Radiography and Tomography Research facilities is envisaged to enhance the group's support for Necsa's mission to undertake and support nuclear research and utilize penetrating radiation for the benefit of mankind. It is envisage that the SANCRAT will host neutron-, X-ray- and gamma ray penetrating radiation imaging infrastructures that can be utilized by researchers from industry as well as post graduate students from higher educational institutions. Modelling for the upgrade to a multifunctional neutron radiography and tomography facility has been underway. Upgrade plans and implementation has also begun for a 250 kV X-ray radiography set-up, that will exist independent from the neutron facility. Future expansion entails catering for a micro-focus X-ray -, and gamma ray radiography and tomography facilities. The current facilities available consist of one infrastructure facility based on two sources of penetrating radiation, i.e. SAFARI-1 research nuclear reactor as thermal neutron source and a 100 kV X-ray generator. This facility, which hosts the only operational neutron tomography R and D facility in the Southern Hemisphere and in Africa, are being extensively utilized by post graduate students and industry. The facility sees application in a wide range of scientific and engineering disciplines, amongst which is nuclear, geosciences, palaeontology, civil, mechanical, chemical, etc. This paper focus on case studies engaged at the current radiography and tomography facilities over the past 2 years as well as describing the envisaged upgrade initiatives to a fully equipped national centre. (authors)

Current radiography and tomography applications at Necsa and an envisaged upgrade towards a proposed South African national centre for radiography and tomography (SANCRAT)

International Nuclear Information System (INIS)

Radebe, M.J.; De Beer, F.C.

2008-01-01

An upgrade of the current Radiography and Tomography Research facilities is envisaged to enhance the group's support for Necsa's mission to undertake and support nuclear research and utilize penetrating radiation for the benefit of mankind. It is envisage that the SANCRAT will host neutron-, X-ray- and gamma ray penetrating radiation imaging infrastructures that can be utilized by researchers from industry as well as post graduate students from higher educational institutions. Modelling for the upgrade to a multifunctional neutron radiography and tomography facility has been underway. Upgrade plans and implementation has also begun for a 250 kV X-ray radiography set-up, that will exist independent from the neutron facility. Future expansion entails catering for a micro-focus X-ray -, and gamma ray radiography and tomography facilities. The current facilities available consist of one infrastructure facility based on two sources of penetrating radiation, i.e. SAFARI-1 research nuclear reactor as thermal neutron source and a 100 kV X-ray generator. This facility, which hosts the only operational neutron tomography R and D facility in the Southern Hemisphere and in Africa, are being extensively utilized by post graduate students and industry. The facility sees application in a wide range of scientific and engineering disciplines, amongst which is nuclear, geosciences, palaeontology, civil, mechanical, chemical, etc. This paper focus on case studies engaged at the current radiography and tomography facilities over the past 2 years as well as describing the envisaged upgrade initiatives to a fully equipped national centre. (authors)

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

Science.gov (United States)

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

Vascular imaging with contrast agent in hard and soft tissues using microcomputed-tomography.

Science.gov (United States)

Blery, P; Pilet, P; Bossche, A Vanden-; Thery, A; Guicheux, J; Amouriq, Y; Espitalier, F; Mathieu, N; Weiss, P

2016-04-01

Vascularization is essential for many tissues and is a main requisite for various tissue-engineering strategies. Different techniques are used for highlighting vasculature, in vivo and ex vivo, in 2-D or 3-D including histological staining, immunohistochemistry, radiography, angiography, microscopy, computed tomography (CT) or micro-CT, both stand-alone and synchrotron system. Vascularization can be studied with or without a contrast agent. This paper presents the results obtained with the latest Skyscan micro-CT (Skyscan 1272, Bruker, Belgium) following barium sulphate injection replacing the bloodstream in comparison with results obtained with a Skyscan In Vivo 1076. Different hard and soft tissues were perfused with contrast agent and were harvested. Samples were analysed using both forms of micro-CT, and improved results were shown using this new micro-CT. This study highlights the vasculature using micro-CT methods. The results obtained with the Skyscan 1272 are clearly defined compared to results obtained with Skyscan 1076. In particular, this instrument highlights the high number of small vessels, which were not seen before at lower resolution. This new micro-CT opens broader possibilities in detection and characterization of the 3-D vascular tree to assess vascular tissue engineering strategies. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Processing of microCT implant-bone systems images using Fuzzy Mathematical Morphology

International Nuclear Information System (INIS)

Bouchet, A; Pastore, J; Colabella, L; Omar, S; Ballarre, J

2016-01-01

The relationship between a metallic implant and the existing bone in a surgical permanent prosthesis is of great importance since the fixation and osseointegration of the system leads to the failure or success of the surgery. Micro Computed Tomography is a technique that helps to visualize the structure of the bone. In this study, the microCT is used to analyze implant-bone systems images. However, one of the problems presented in the reconstruction of these images is the effect of the iron based implants, with a halo or fluorescence scattering distorting the micro CT image and leading to bad 3D reconstructions. In this work we introduce an automatic method for eliminate the effect of AISI 316L iron materials in the implant-bone system based on the application of Compensatory Fuzzy Mathematical Morphology for future investigate about the structural and mechanical properties of bone and cancellous materials. (paper)

Aaron V. Cicourel : de l’ethnométhodologie au problème micro/macro en sciences sociales

Directory of Open Access Journals (Sweden)

Philippe Corcuff

2008-10-01

Full Text Available Présentation et introduction du texte d’Aaron V. Cicourel « Notes on the integration of micro- and macro-levels of analysis », extrait de l’ouvrage Advances in Social Theory and Methodology – Toward an Integration of Micro- and Macro-Sociologies, édité par Karin D. Knorr-Cetina et Aaron V. Cicourel, Boston, London and Henley, Routledge and Kegan Paul, 1981, pp.51-80. Traduction française par Alain Accardo et Francis Chateauraynaud, révisée par Philippe Corcuff. Publié avec l’aimable autorisation de l’auteur.Cet article s’efforce de resituer le texte, traduit pour la première fois ici en langue française, dans le parcours scientifique du sociologue américain, né en 1928, relativement méconnu dans le monde francophone. Il retrace son évolution de l’ethnométhodologie à la sociologie cognitive. Puis il s’intéresse à ses originalités quant au problème micro/macro. Dans ces deux principales parties, l’auteur est amené à mettre en évidence des convergences et des différences avec des sociologues importants : Pierre Bourdieu, Harold Garfinkel et Erving Goffman.Aaron V. Cicourel : from ethnomethodology to the micro/macro problem in social sciencesIntroduction to the Aaron V. Cicourel’s text, « Micro-processes and macro-structures » (1981Presentation and introduction of Aaron V. Cicourel’s text « Notes on the integration of micro- and macro-levels of analysis », taken from Advances in Social Theory and Methodology – Toward an Integration of Micro- and Macro-Sociologies, edited by Karin D. Knorr-Cetina and Aaron V. Cicourel, Boston, London and Henley, Routledge and Kegan Paul, 1981, pp.51-80. French translation by Alain Accardo and Francis Chateauraynaud, revised by Philippe Corcuff. Published with the pleasant authorization of the author. This text is translated here in French for the first time. This article intends to put in perspective the text in the scientific course of the American

Micro-CT image reconstruction based on alternating direction augmented Lagrangian method and total variation.

Science.gov (United States)

Gopi, Varun P; Palanisamy, P; Wahid, Khan A; Babyn, Paul; Cooper, David

2013-01-01

Micro-computed tomography (micro-CT) plays an important role in pre-clinical imaging. The radiation from micro-CT can result in excess radiation exposure to the specimen under test, hence the reduction of radiation from micro-CT is essential. The proposed research focused on analyzing and testing an alternating direction augmented Lagrangian (ADAL) algorithm to recover images from random projections using total variation (TV) regularization. The use of TV regularization in compressed sensing problems makes the recovered image quality sharper by preserving the edges or boundaries more accurately. In this work TV regularization problem is addressed by ADAL which is a variant of the classic augmented Lagrangian method for structured optimization. The per-iteration computational complexity of the algorithm is two fast Fourier transforms, two matrix vector multiplications and a linear time shrinkage operation. Comparison of experimental results indicate that the proposed algorithm is stable, efficient and competitive with the existing algorithms for solving TV regularization problems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bilateral optic neuropathy and intraretinal deposits after pars plana vitrectomy in amyloidosis

Directory of Open Access Journals (Sweden)

Rossetti Alberto

2015-01-01

Full Text Available Pathological examination of material from a nonextensive pars plana vitrectomy (PPV in the right eye provided a diagnosis of nonfamilial amyloidosis in a 68-year-old woman, who presented with bilateral glass wool-like vitreous opacities. Genetic testing revealed a Tyr114Cys mutation in the transthyretin gene. Six months after PPV, perimetry showed intense constriction with a temporal island and central scotoma in the right eye. An extensive PPV was performed in the left eye. Spectral domain optical coherence tomography evidenced bilateral epimacular amyloid deposits and unreported reflective spots within the inner retina. One year later, visual acuity had decreased to 20/400 in the left eye, with mild vitreous opacity, pale cupped optic disc and inferior altitudinal field defect. Bilateral diurnal intraocular pressure, transiently increased after PPV, never exceeded 16 mmHg with medication. Our patient presented optic nerve blood supply impairment, due to amyloidosis, which caused optic atrophy. Epiretinal and intraretinal deposit detection could aid in diagnosing patients with suspected amyloidosis.

Movement and equipositioning of plasmids by ParA filament disassembly

DEFF Research Database (Denmark)

Ringgaard, Simon; van Zon, Jeroen; Howard, Martin

2009-01-01

, plasmids consistently migrate behind disassembling ParA cytoskeletal structures, suggesting that ParA filaments pull plasmids by depolymerization. The perpetual cycles of ParA assembly and disassembly result in continuous relocation of plasmids, which, on time averaging, results in equidistribution...

PAR-1 contributes to the innate immune response during viral infection

Science.gov (United States)

Antoniak, Silvio; Owens, A. Phillip; Baunacke, Martin; Williams, Julie C.; Lee, Rebecca D.; Weithäuser, Alice; Sheridan, Patricia A.; Malz, Ronny; Luyendyk, James P.; Esserman, Denise A.; Trejo, JoAnn; Kirchhofer, Daniel; Blaxall, Burns C.; Pawlinski, Rafal; Beck, Melinda A.; Rauch, Ursula; Mackman, Nigel

2013-01-01

Coagulation is a host defense system that limits the spread of pathogens. Coagulation proteases, such as thrombin, also activate cells by cleaving PARs. In this study, we analyzed the role of PAR-1 in coxsackievirus B3–induced (CVB3-induced) myocarditis and influenza A infection. CVB3-infected Par1–/– mice expressed reduced levels of IFN-β and CXCL10 during the early phase of infection compared with Par1+/+ mice that resulted in higher viral loads and cardiac injury at day 8 after infection. Inhibition of either tissue factor or thrombin in WT mice also significantly increased CVB3 levels in the heart and cardiac injury compared with controls. BM transplantation experiments demonstrated that PAR-1 in nonhematopoietic cells protected mice from CVB3 infection. Transgenic mice overexpressing PAR-1 in cardiomyocytes had reduced CVB3-induced myocarditis. We found that cooperative signaling between PAR-1 and TLR3 in mouse cardiac fibroblasts enhanced activation of p38 and induction of IFN-β and CXCL10 expression. Par1–/– mice also had decreased CXCL10 expression and increased viral levels in the lung after influenza A infection compared with Par1+/+ mice. Our results indicate that the tissue factor/thrombin/PAR-1 pathway enhances IFN-β expression and contributes to the innate immune response during single-stranded RNA viral infection. PMID:23391721

Effects of low-intensity pulsed ultrasound on new trabecular bone during bone-tendon junction healing in a rabbit model: a synchrotron radiation micro-CT study.

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Hongbin Lu

Full Text Available This study was designed to evaluate the effects of low-intensity pulsed ultrasound on bone regeneration during the bone-tendon junction healing process and to explore the application of synchrotron radiation micro computed tomography in three dimensional visualization of the bone-tendon junction to evaluate the microarchitecture of new trabecular bone. Twenty four mature New Zealand rabbits underwent partial patellectomy to establish a bone-tendon junction injury model at the patella-patellar tendon complex. Animals were then divided into low-intensity pulsed ultrasound treatment (20 min/day, 7 times/week and placebo control groups, and were euthanized at week 8 and 16 postoperatively (n = 6 for each group and time point. The patella-patellar tendon specimens were harvested for radiographic, histological and synchrotron radiation micro computed tomography detection. The area of the newly formed bone in the ultrasound group was significantly greater than that of control group at postoperative week 8 and 16. The high resolution three dimensional visualization images of the bone-tendon junction were acquired by synchrotron radiation micro computed tomography. Low-intensity pulsed ultrasound treatment promoted dense and irregular woven bone formation at week 8 with greater bone volume fraction, number and thickness of new trabecular bone but with lower separation. At week 16, ultrasound group specimens contained mature lamellar bone with higher bone volume fraction and thicker trabeculae than that of control group; however, there was no significant difference in separation and number of the new trabecular bone. This study confirms that low-intensity pulsed ultrasound treatment is able to promote bone formation and remodeling of new trabecular bone during the bone-tendon junction healing process in a rabbit model, and the synchrotron radiation micro computed tomography could be applied for three dimensional visualization to quantitatively evaluate

Evaluating the hydraulic and transport properties of peat soil using pore network modeling and X-ray micro computed tomography

Science.gov (United States)

Gharedaghloo, Behrad; Price, Jonathan S.; Rezanezhad, Fereidoun; Quinton, William L.

2018-06-01

Micro-scale properties of peat pore space and their influence on hydraulic and transport properties of peat soils have been given little attention so far. Characterizing the variation of these properties in a peat profile can increase our knowledge on the processes controlling contaminant transport through peatlands. As opposed to the common macro-scale (or bulk) representation of groundwater flow and transport processes, a pore network model (PNM) simulates flow and transport processes within individual pores. Here, a pore network modeling code capable of simulating advective and diffusive transport processes through a 3D unstructured pore network was developed; its predictive performance was evaluated by comparing its results to empirical values and to the results of computational fluid dynamics (CFD) simulations. This is the first time that peat pore networks have been extracted from X-ray micro-computed tomography (μCT) images of peat deposits and peat pore characteristics evaluated in a 3D approach. Water flow and solute transport were modeled in the unstructured pore networks mapped directly from μCT images. The modeling results were processed to determine the bulk properties of peat deposits. Results portray the commonly observed decrease in hydraulic conductivity with depth, which was attributed to the reduction of pore radius and increase in pore tortuosity. The increase in pore tortuosity with depth was associated with more decomposed peat soil and decreasing pore coordination number with depth, which extended the flow path of fluid particles. Results also revealed that hydraulic conductivity is isotropic locally, but becomes anisotropic after upscaling to core-scale; this suggests the anisotropy of peat hydraulic conductivity observed in core-scale and field-scale is due to the strong heterogeneity in the vertical dimension that is imposed by the layered structure of peat soils. Transport simulations revealed that for a given solute, the effective

Retention assessment of magnetic nanoparticles in rat arteries with micro-computed tomography.

Science.gov (United States)

Tu, Shu-Ju; Wu, Siao-Yun; Wang, Fu-Sheng; Ma, Yunn-Hwa

2014-03-07

Magnetic nanoparticles (MNPs) may serve as carriers for pharmacological agents to the target in a magnetic-force guiding system. It is essential to achieve effective retention of MNPs through the external magnet placement. However, it is difficult to estimate the retention efficiency of MNPs and validate the experimental strategies. Micro-CT was used to identify the spatial distribution of MNP retention and image analysis is then extended to evaluate the MNP delivery efficiency. Male Sprague Dawley rats were anesthetized to expose abdominal arteries with an NdFeB magnet of 4.9 kG placed by the left iliac artery. After a 20 min equilibrium period, arteries were ligated, removed and fixed in a paraformaldehyde solution. Experiments were performed with intravenous injection in our platform with two independent groups. MNPs were used in the first group, while chemical compounds of recombinant tissue plaminogen activator were attached to MNPs as rtPA (recombinant tissue plaminogen activator)-MNPs in the second group. Image analysis of micro-CT shows the average retention volume of MNPs and rtPA-MNPs in the left iliac arteries is 9.3 and 6.3 fold of that in the right. Large local aggregation of MNPs and rtPA-MNPs in the left iliac arteries is the consequence of external magnet placement, suggesting feasibility of magnetic targeting through the intravenous administration. We also determined that on average 0.57% and 0.064% of MNPs and rtPA-MNPs respectively were retained in the left iliac artery. It was estimated that the average rtPA concentration of 60.16 µg mL(-1) may be achieved with rtPA-MNPs. With the micro-CT imaging approach, we accomplished visualization of the aggregation of retained particles; reconstructed 3D distribution of relative retention; estimated the average particle number of local retention; determined efficiency of targeted delivery. In particular, our quantitative image assessment suggests that intravenous administration of rtPA-MNPs may retain

Peptide-Based Optical uPAR Imaging for Surgery

DEFF Research Database (Denmark)

Juhl, Karina; Christensen, Anders; Persson, Morten

2016-01-01

Near infrared intra-operative optical imaging is an emerging technique with clear implications for improved cancer surgery by enabling a more distinct delineation of the tumor margins during resection. This modality has the potential to increase the number of patients having a curative radical...... tumor resection. In the present study, a new uPAR-targeted fluorescent probe was developed and the in vivo applicability was evaluated in a human xenograft mouse model. Most human carcinomas express high level of uPAR in the tumor-stromal interface of invasive lesions and uPAR is therefore considered...... an ideal target for intra-operative imaging. Conjugation of the flourophor indocyanine green (ICG) to the uPAR agonist (AE105) provides an optical imaging ligand with sufficiently high receptor affinity to allow for a specific receptor targeting in vivo. For in vivo testing, human glioblastoma xenograft...

Phase contrast enhanced high resolution X-ray imaging and tomography of soft tissue

International Nuclear Information System (INIS)

Jakubek, Jan; Granja, Carlos; Dammer, Jiri; Hanus, Robert; Holy, Tomas; Pospisil, Stanislav; Tykva, Richard; Uher, Josef; Vykydal, Zdenek

2007-01-01

A tabletop system for digital high resolution and high sensitivity X-ray micro-radiography has been developed for small-animal and soft-tissue imaging. The system is based on a micro-focus X-ray tube and the semiconductor hybrid position sensitive Medipix2 pixel detector. Transmission radiography imaging, conventionally based only on absorption, is enhanced by exploiting phase-shift effects induced in the X-ray beam traversing the sample. Phase contrast imaging is realized by object edge enhancement. DAQ is done by a novel fully integrated USB-based readout with online image generation. Improved signal reconstruction techniques make use of advanced statistical data analysis, enhanced beam hardening correction and direct thickness calibration of individual pixels. 2D and 3D micro-tomography images of several biological samples demonstrate the applicability of the system for biological and medical purposes including in-vivo and time dependent physiological studies in the life sciences

The value of SPECT in the detection of stress injury to the pars interarticularis in patients with low back pain

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Grant Frederick D

2010-03-01

Full Text Available Abstract The medical cost associated with back pain in the United States is considerable and growing. Although the differential diagnosis of back pain is broad, epidemiological studies suggest a correlation between adult and adolescent complaints. Injury of the pars interarticularis is one of the most common identifiable causes of ongoing low back pain in adolescent athletes. It constitutes a spectrum of disease ranging from bone stress to spondylolysis and spondylolisthesis. Bone stress may be the earliest sign of disease. Repetitive bone stress causes bone remodeling and may result in spondylolysis, a non-displaced fracture of the pars interarticularis. A fracture of the pars interarticularis may ultimately become unstable leading to spondylolisthesis. Results in the literature support the use of bone scintigraphy to diagnose bone stress in patients with suspected spondylolysis. Single photon emission computed tomography (SPECT provides more contrast than planar bone scintigraphy, increases the sensitivity and improves anatomic localization of skeletal lesions without exposing the patient to additional radiation. It also provides an opportunity for better correlation with other imaging modalities, when necessary. As such, the addition of SPECT to standard planar bone scintigraphy can result in a more accurate diagnosis and a better chance for efficient patient care. It is our expectation that by improving our ability to correctly diagnose bone stress in patients with suspected injury of the posterior elements, the long-term cost of managing this condition will be lowered.

Differential phase microscope and micro-tomography with a Foucault knife-edge scanning filter

Science.gov (United States)

Watanabe, N.; Hashizume, J.; Goto, M.; Yamaguchi, M.; Tsujimura, T.; Aoki, S.

2013-10-01

An x-ray differential phase microscope with a Foucault knife-edge scanning filter was set up at the bending magnet source BL3C, Photon Factory. A reconstructed phase profile from the differential phase image of an aluminium wire at 5.36 keV was fairly good agreement with the numerical simulation. Phase tomography of a biological specimen, such as an Artemia cyst, could be successfully demonstrated.

Value of micro-CT as an Investigative Tool for Osteochondritis Dissecans. A preliminary study with comparison to histology

International Nuclear Information System (INIS)

Mohr, A.; Bergmann, I.; Muhle, C.; Heller, M.; Heiss, C.; Schrader, C.; Roemer, F.W.; Lynch, J.A.; Genant, H.K.

2003-01-01

Purpose: To evaluate micro computed tomography (micro-CT) for the assessment of osteochondritis dissecans in comparison with histology. Material and Methods: Osteochondritis dissecans lesions of 3 patients were evaluated using micro-CT (0.125 mA, 40 keV, 60 m slice thickness, 60 m isotropic resolution, entire sample) and light microscopy (toluidine blue, 3-5 m slice thickness). The methods were compared regarding preparation time, detectability of tissue types and morphologic features of bone and cartilage. Results: Non-destructive micro-CT imaging of the entire sample was faster than histologic preparation of a single slice for light microscopy. Morphologic features of bone and cartilage could be imaged in a comparable way to histology. It was not possible to image cells or different tissue types of bone and cartilage with micro-CT. Conclusion: Micro-CT is a fast, non-destructive tool that may be a supplement or, if detailed histologic information is not necessary, an alternative to light microscopy for the investigation of osteochondritis dissecans. Osteochondritis dissecans micro-CT histology comparative investigation

Study of bony trabecular characteristics using bone morphometry and micro-CT

International Nuclear Information System (INIS)

Song, Young Han; Lee, Wan; Lee, Chang Jin; Ji, Jung Hyun; Lee, Byung Do

2007-01-01

The research was done to investigate the effectiveness of 2D bony morphometry and microstructure of micro-computed tomography (micro-CT) on the osteoporotic bony change. We performed the bone morphometric analysis of proximal femur in ovariectomized rabbits with BMD and micro-CT examination. Twenty-one female (Newzeland, about 16 weeks old, 2.9-3.4 kg) rabbits were used. Three rabbits were sacrificed on the day when experiment began (Basline). The remaining 18 rabbits were divided into two groups. One group was ovariectomized bilaterally (OVX) and the other animals were subjected to sham operation (Sham). Bone specimens were obtained from the right and left femur of sacrificed rabbits. At intervals of 1,2,3,5,6 months respectively, BMD tests were performed on the proximal on the proximal femur by using PIXImus 2 (GE Lunar Co. USA), 2-dimensional bone morphometric analysis by custom computer program and 2D / 3D bone structure analysis by micro-CT (Skyscan1072, Antwerpen, Belgium). Statistical analysis was carried out for the correlation between bone morphometry, micro-CT and BMD. BV/TV, Tb.Th, Tb.N of micro-CT parameters showed higher values in sham group than OVX group. N.Nd/Ar.RI, N.NdNd, N.NdTm, N. TmTm, PmB/Ar.RI, 3-D BoxSlope of 2D morphometric parameters showed higher values in Sham group than OVX group. The micro-CT parameters of Tb.Sp. Tb.N were statistically significant correlated with BMD respectively. Several 2D morphometric parameters were statistically significant correlated with BMD respectively. Several parameters of 2D bony morphometry and micro-CT showed effective aspects on the osteoporotic bony change

The dental cavities of equine cheek teeth: three-dimensional reconstructions based on high resolution micro-computed tomography

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Kopke Susan

2012-09-01

Full Text Available Abstract 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

Seismic micro-zoning in the alpine valleys and local application in urban planning regulations

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Stéphane Cartier

2009-03-01

Full Text Available Confrontées au risque sismique, les vallées sédimentaires alpines testent différentes solutions politiques pour transcrire en règles d’urbanisme les connaissances apportées par les micro-zonages. France, Italie, Slovénie et Suisse composent avec leur tradition politique et l’adoption de codes européens pour améliorer la sécurité selon la vulnérabilité et la géologie locales.Management of earthquake risks in the sedimentary valleys of the Alps depends on the ability to transcribe scientific knowledge obtained from micro-zoning into urban planning regulations. France, Italy, Slovenia and Switzerland are working with new European codes, and within their respective political contexts, to improve earthquake safety on the basis of enhanced input on local geological conditions and vulnerability levels.

Measurement of micro moulded parts by Computed Tomography and comparison to optical and tactile techniques

DEFF Research Database (Denmark)

Yagüe, J.A.; Tosello, Guido; Carmignato, S

2011-01-01

This paper focuses on dimensional verification of two micro-injection moulded components, selected from actual industrial productions, using CT metrological tools. In addition to CT scanning, also a tactile Coordinate Measuring Machine (CMM) with sub-micrometer uncertainty and an Optical Coordinate...... Measuring Machine (OCMM) allowing fast measurements suitable for in-line quality control were employed as validation instruments. The experimental work carried out and the analysis of the results provide valuable conclusions about the advantages and drawbacks of using CT metrology in comparison with CMM...... and OCMM when these techniques are employed for quality control of micro moulded parts....

Application of three-dimensional computed tomography in craniofacial clinical practice and research.

Science.gov (United States)

Anderson, P J; Yong, R; Surman, T L; Rajion, Z A; Ranjitkar, S

2014-06-01

Following the invention of the first computed tomography (CT) scanner in the early 1970s, many innovations in three-dimensional (3D) diagnostic imaging technology have occurred, leading to a wide range of applications in craniofacial clinical practice and research. Three-dimensional image analysis provides superior and more detailed information compared with conventional plain two-dimensional (2D) radiography, with the added benefit of 3D printing for preoperative treatment planning and regenerative therapy. Current state-of-the-art multidetector CT (MDCT), also known as medical CT, has an important role in the diagnosis and management of craniofacial injuries and pathology. Three-dimensional cone beam CT (CBCT), pioneered in the 1990s, is gaining increasing popularity in dental and craniofacial clinical practice because of its faster image acquisition at a lower radiation dose, but sound guidelines are needed to ensure its optimal clinical use. Recent innovations in micro-computed tomography (micro-CT) have revolutionized craniofacial biology research by enabling higher resolution scanning of teeth beyond the capabilities of MDCT and CBCT, presenting new prospects for translational clinical research. Even after four decades of refinement, CT technology continues to advance and broaden the horizons of craniofacial clinical practice and phenomics research. © 2014 Australian Dental Association.

Non-Conventional Applications of Computerized Tomography: Analysis of Solid Dosage Forms Produced by Pharmaceutical Industry

International Nuclear Information System (INIS)

Martins de Oliveira, Jose Jr.; Germano Martins, Antonio Cesar

2010-01-01

X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe a non-conventional application of computerized tomography: visualization and improvements in the understanding of some internal structural features of solid dosage forms. A micro-CT X-ray scanner, with a minimum resolution of 30 μm was used to characterize some pharmaceutical tablets, granules, controlled-release osmotic tablet and liquid-filled soft-gelatin capsules. The analysis presented in this work are essentially qualitative, but quantitative parameters, such as porosity, density distribution, tablets dimensions, etc. could also be obtained using the related CT techniques.

Dynamic Filament Formation by a Divergent Bacterial Actin-Like ParM Protein.

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Anthony J Brzoska

Full Text Available Actin-like proteins (Alps are a diverse family of proteins whose genes are abundant in the chromosomes and mobile genetic elements of many bacteria. The low-copy-number staphylococcal multiresistance plasmid pSK41 encodes ParM, an Alp involved in efficient plasmid partitioning. pSK41 ParM has previously been shown to form filaments in vitro that are structurally dissimilar to those formed by other bacterial Alps. The mechanistic implications of these differences are not known. In order to gain insights into the properties and behavior of the pSK41 ParM Alp in vivo, we reconstituted the parMRC system in the ectopic rod-shaped host, E. coli, which is larger and more genetically amenable than the native host, Staphylococcus aureus. Fluorescence microscopy showed a functional fusion protein, ParM-YFP, formed straight filaments in vivo when expressed in isolation. Strikingly, however, in the presence of ParR and parC, ParM-YFP adopted a dramatically different structure, instead forming axial curved filaments. Time-lapse imaging and selective photobleaching experiments revealed that, in the presence of all components of the parMRC system, ParM-YFP filaments were dynamic in nature. Finally, molecular dissection of the parMRC operon revealed that all components of the system are essential for the generation of dynamic filaments.

Exploring miniature insect brains using micro-CT scanning techniques

Science.gov (United States)

Smith, Dylan B.; Bernhardt, Galina; Raine, Nigel E.; Abel, Richard L.; Sykes, Dan; Ahmed, Farah; Pedroso, Inti; Gill, Richard J.

2016-01-01

The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures. PMID:26908205

Late-Onset Inadvertent Bleb Formation following Pars Plana M3 Molteno Implant Tube Obstruction

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Anmar M. Abdul-Rahman

2017-01-01

Full Text Available Purpose: To report a case of inadvertent bleb formation presenting 18 months after pars plana M3 Molteno implant tube obstruction in a patient with mixed mechanism glaucoma. Materials and Methods: An 84-year-old Caucasian male with mixed mechanism glaucoma underwent slit-lamp examination, gonioscopy, colour anterior segment photography and anterior segment optical coherence tomography (AS-OCT. Results: An inadvertent bleb developed 18 months after pars plana implant tube re-positioning with a 6/0 Vicryl tie ligature. The bleb was located in the area anterior to the implant plate; it was characterised by a thin, transparent, avascular and multi-cystic wall, with a visible stoma at the posterior edge of the bleb. The bleb was functioning as demonstrated by an intraocular pressure of 6 mm Hg at presentation and a punctate fluorescein uptake pattern of the bleb wall. The bleb over the plate of the Molteno implant was non-functioning, likely secondary to tube obstruction by vitreous in the early postoperative period. AS-OCT showed a tract from the anterior chamber commencing at an entry wound through a corneal tunnel to the posterior stoma at the base of the inadvertent bleb. Conclusions: We hypothesise that the pathophysiologic factors resulting in an inadvertent bleb are a result of a combination of apoptosis, late-onset wound dehiscence and internal gaping of a centrally placed corneal wound. In addition, aqueous hydrodynamic factors may play a role.

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

Science.gov (United States)

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.

Using Micro-Computed Tomography to Evaluate the Dynamics of Orthodontically Induced Root Resorption Repair in a Rat Model.

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Xiaolin Xu

Full Text Available To observe dynamic changes in root resorption repair, tooth movement relapse and alveolar bone microstructure following the application of orthodontic force.Forces of 20 g, 50 g or 100 g were delivered to the left maxillary first molars of fifteen 10-week-old rats for 14 days. Each rat was subjected to micro-computed tomography scanning at 0, 3, 7, 10, 14, 28 and 42 days after force removal. The root resorption crater volume, tooth movement relapse and alveolar bone microarchitecture were measured at each time point.From day 3 to day 14, the root resorption volume decreased significantly in each group. In the 20-g force group, the root resorption volume gradually stabilized after 14 days, whereas in the 50-g and 100-g force groups, it stabilized after 28 days. In all groups, tooth movement relapsed significantly from day 0 to day 14 and then remained stable. From day 3 to day 10, the 20-g group exhibited faster relapse than the 50-g and 100-g groups. In all groups, the structure model index and trabecular separation decreased slowly from day 0 to day 10 and eventually stabilized. Trabecular number increased slowly from day 0 to day 7 and then stabilized.The initial stage of root resorption repair did not change significantly and was followed by a dramatic repair period before stabilizing. The most serious tooth movement relapse occurred immediately after the appliance was removed, and then the tooth completely returned to the original position.

Narrative Identities and the Plebiscite in Pará: An Analysis of the Front Pages for O Liberal and Diário do Pará

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Alda Cristina Silva da Costa

2017-05-01

Full Text Available On December 11, 2011, a plebiscite was held in Pará proposing to create two separatist states, Carajás and Tapajós, out of the state of Pará. The public voted against both projects. This article analyzes the narrative identities found on the front pages of O Liberal and Diário do Pará newspapers about the plebiscite in Pará. Depth Hermeneutics (DH, as proposed by Thompson (2011, was used as the methodological reference. DH emphasizes the object of analysis as a meaningful symbolic construction requiring interpretation. Narrative analysis, as proposed by Motta (2007, was the main research technique used to highlight the movement of construction of journalistic (discursive characters. The narrative identities built by the two newspapers showed that both were against the creation of the new states, but for very different reasons. The flag of Pará was the main object used to induce the idea of unity. Em 11 de dezembro de 2011, o plebiscito no Pará propôs a criação dos estados de Carajás e de Tapajós a partir da divisão do estado do Pará. O resultado da consulta pública foi negativo aos dois projetos. O artigo analisa as identidades narrativas constituídas pelas primeiras páginas dos jornais O Liberal e Diário do Pará sobre o plebiscito no Pará. Utilizou-se como referencial metodológico a Hermenêutica em Profundidade (HP, proposta por Thompson (2011. A HP evidencia o fato de que o objeto de análise é uma construção simbólica significativa, que exige uma interpretação. Como principal técnica de pesquisa, a análise narrativa, proposta por Motta (2007, com ênfase no movimento de construção de personagens jornalísticas (discursivas. As identidades narrativas construídas pelos dois jornais indicaram que ambos eram contrários à criação dos novos estados, porém por motivos divergentes. A bandeira do Pará foi o principal elemento utilizado para evocar a ideia de unidade. En 11 de diciembre de 2011, el plebiscito en

Limnological database for Par Pond: 1959 to 1980

International Nuclear Information System (INIS)

Tilly, L.J.

1981-03-01

A limnological database for Par Pond, a cooling reservoir for hot reactor effluent water at the Savannah River Plant, is described. The data are derived from a combination of research and monitoring efforts on Par Pond since 1959. The approximately 24,000-byte database provides water quality, primary productivity, and flow data from a number of different stations, depths, and times during the 22-year history of the Par Pond impoundment. The data have been organized to permit an interpretation of the effects of twenty years of cooling system operations on the structure and function of an aquatic ecosystem

Improved method of in vivo respiratory-gated micro-CT imaging

Energy Technology Data Exchange (ETDEWEB)

Walters, Erin B; Panda, Kunal; Bankson, James A; Brown, Ellana; Cody, Dianna D [Department of Imaging Physics, Unit 56, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030 (United States)

2004-09-07

The presence of motion artifacts is a typical problem in thoracic imaging. However, synchronizing the respiratory cycle with computed tomography (CT) image acquisition can reduce these artifacts. We currently employ a method of in vivo respiratory-gated micro-CT imaging for small laboratory animals (mice). This procedure involves the use of a ventilator that controls the respiratory cycle of the animal and provides a digital output signal that is used to trigger data acquisition. After inspection of the default respiratory trigger timing, we hypothesized that image quality could be improved by moving the data-acquisition window to a portion of the cycle with less respiratory motion. For this reason, we developed a simple delay circuit to adjust the timing of the ventilator signal that initiates micro-CT data acquisition. This delay circuit decreases motion artifacts and substantially improves image quality.

Improved method of in vivo respiratory-gated micro-CT imaging

International Nuclear Information System (INIS)

Walters, Erin B; Panda, Kunal; Bankson, James A; Brown, Ellana; Cody, Dianna D

2004-01-01

The presence of motion artifacts is a typical problem in thoracic imaging. However, synchronizing the respiratory cycle with computed tomography (CT) image acquisition can reduce these artifacts. We currently employ a method of in vivo respiratory-gated micro-CT imaging for small laboratory animals (mice). This procedure involves the use of a ventilator that controls the respiratory cycle of the animal and provides a digital output signal that is used to trigger data acquisition. After inspection of the default respiratory trigger timing, we hypothesized that image quality could be improved by moving the data-acquisition window to a portion of the cycle with less respiratory motion. For this reason, we developed a simple delay circuit to adjust the timing of the ventilator signal that initiates micro-CT data acquisition. This delay circuit decreases motion artifacts and substantially improves image quality

Hybrid Spectral Micro-CT: System Design, Implementation, and Preliminary Results

CERN Document Server

Bennett, James R; Xu, Qiong; Yu, Hengyong; Walsh, Michael; Butler, Anthony; Butler, Phillip; Cao, Guohua; Mohs, Aaron; Wang, Ge

2014-01-01

Spectral CT has proven an important development in biomedical imaging, and there have been several publications in the past years demonstrating its merits in pre-clinical and clinical applications. In 2012, Xu et al. reported that near-term implementation of spectral micro-CT could be enhanced by a hybrid architecture: a narrow-beam spectral "interior" imaging chain integrated with a traditional wide-beam "global" imaging chain. This hybrid integration coupled with compressive sensing (CS)-based interior tomography demonstrated promising results for improved contrast resolution, and decreased system cost and radiation dose. The motivation for the current study is implementation and evaluation of the hybrid architecture with a first-of-its-kind hybrid spectral micro-CT system. Preliminary results confirm improvements in both contrast and spatial resolution. This technology is shown to merit further investigation and potential application in future spectral CT scanner design.

Soluble urokinase plasminogen activator receptor (suPAR) in acute care

DEFF Research Database (Denmark)

Rasmussen, Line Jee Hartmann; Ladelund, Steen; Haupt, Thomas Huneck

2016-01-01

for age, sex, Charlson score and C reactive protein. Area under the curve for receiver operating characteristics curve analysis of suPAR for 30-day mortality was 0.84 (95% CI 0.81 to 0.86). Furthermore, in the entire cohort, women had slightly higher suPAR compared with men, and suPAR was associated...

Non-oncological positron emission tomography (PET): brain imaging; La tomographie par emission de positons (TEP) hors oncologie: l'exploration du cerveau

Energy Technology Data Exchange (ETDEWEB)

Lomena, F. [Centro de Diagnostico por la imagen (CDIC), Hospital Clinic, Servicio de medicina nuclear, Barcelona (Spain)

2008-10-15

Positron emission tomography (PET) allows evaluation of the central nervous system function. Imaging of regional cerebral blood flow and metabolism, and of several neurotransmission systems may be obtained using PET. PET quantification is accurate and has good test-retest reliability. For research purposes, PET has been used to study brain physiology, to explore neurological and psychiatric diseases pathophysiology and for the new drugs research and development. F.D.G. is the only PET radioligand with clinical application. Following criteria of evidence-based medicine, the clinical indications of F.D.G.-PET are: evaluation of treated gliomas, pre surgical study of partial refractory epilepsy and diagnosis of Alzheimer's disease when it is impossible to differentiate clinically from fronto-temporal dementia.

Pars Plana Vitrectomy with Internal Limiting Membrane Peeling for Nontractional Diabetic Macular Edema.

Science.gov (United States)

Ulrich, Jan Niklas

2017-01-01

Diabetes mellitus remains the leading cause of blindness among working age Americans with diabetic macular edema being the most common cause for moderate and severe vision loss. To investigate the anatomical and visual benefits of pars plana vitrectomy with inner limiting membrane peeling in patients with nontractional diabetic macular edema as well as correlation of integrity of outer retinal layers on spectral domain optical coherence tomography to visual outcomes. We retrospectively reviewed the charts of 42 diabetic patients that underwent vitrectomy with internal limiting membrane peeling for nontractional diabetic macula edema. The integrity of outer retinal layers was evaluated and preoperative central macular thickness and visual acuity were compared with data at 1 month, 3 months and 6 months postoperatively. The student t-test was used to compare the groups. 31 eyes were included. While no differences were seen at 1 and 3 months, there was significant improvement of both central macular thickness and visual acuity at the 6 months follow up visit compared to preoperatively (357, 427 microns; p=0.03. 20/49, 20/82; p=0.03) . Patients with intact external limiting membrane and ellipsoid zone had better preoperative vision than patients with outer retinal layer irregularities (20/54, 20/100; p=0.03) and greater visual gains postoperatively (20/33, ppeeling can improve retinal anatomy and visual acuity in patients with nontractional diabetic macular edema. Spectral domain optical coherence tomography may help identify patients with potential for visual improvement.

Barbed micro-spikes for micro-scale biopsy

Science.gov (United States)

Byun, Sangwon; Lim, Jung-Min; Paik, Seung-Joon; Lee, Ahra; Koo, Kyo-in; Park, Sunkil; Park, Jaehong; Choi, Byoung-Doo; Seo, Jong Mo; Kim, Kyung-ah; Chung, Hum; Song, Si Young; Jeon, Doyoung; Cho, Dongil

2005-06-01

Single-crystal silicon planar micro-spikes with protruding barbs are developed for micro-scale biopsy and the feasibility of using the micro-spike as a micro-scale biopsy tool is evaluated for the first time. The fabrication process utilizes a deep silicon etch to define the micro-spike outline, resulting in protruding barbs of various shapes. Shanks of the fabricated micro-spikes are 3 mm long, 100 µm thick and 250 µm wide. Barbs protruding from micro-spike shanks facilitate the biopsy procedure by tearing off and retaining samples from target tissues. Micro-spikes with barbs successfully extracted tissue samples from the small intestines of the anesthetized pig, whereas micro-spikes without barbs failed to obtain a biopsy sample. Parylene coating can be applied to improve the biocompatibility of the micro-spike without deteriorating the biopsy function of the micro-spike. In addition, to show that the biopsy with the micro-spike can be applied to tissue analysis, samples obtained by micro-spikes were examined using immunofluorescent staining. Nuclei and F-actin of cells which are extracted by the micro-spike from a transwell were clearly visualized by immunofluorescent staining.

Intact and cleaved uPAR forms: diagnostic and prognostic value in cancer

DEFF Research Database (Denmark)

Rasch, M.G.; Lund, I.K.; Hoyer-Hansen, G.

2008-01-01

identified in tissue and body fluids. It is well-established, that the total amount of all uPAR forms is a strong prognostic marker in different types of cancer. Using immunoassays, measuring the individual uPAR forms, has revealed that the cleaved uPAR forms are even stronger prognostic markers and have...... diagnostic utility. This review will focus on the mechanism of uPAR cleavage and the functional consequences, as well as the clinical applicability of cleaved uPAR forms Udgivelsesdato: 2008...

Trabecular bone structure parameters from 3D image processing of clinical multi-slice and cone-beam computed tomography data

Energy Technology Data Exchange (ETDEWEB)

Klintstroem, Eva; Smedby, Oerjan [Linkoeping University, Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden); UHL County Council of Oestergoetland, Department of Radiology, Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences (IMH)/Radiology, Linkoeping (Sweden); Moreno, Rodrigo [Linkoeping University, Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences (IMH)/Radiology, Linkoeping (Sweden); Brismar, Torkel B. [KUS Huddinge, Department of Clinical Science, Intervention and Technology at Karolinska Institutet and Department of Radiology, Stockholm (Sweden)

2014-02-15

Bone strength depends on both mineral content and bone structure. The aim of this in vitro study was to develop a method of quantitatively assessing trabecular bone structure by applying three-dimensional image processing to data acquired with multi-slice and cone-beam computed tomography using micro-computed tomography as a reference. Fifteen bone samples from the radius were examined. After segmentation, quantitative measures of bone volume, trabecular thickness, trabecular separation, trabecular number, trabecular nodes, and trabecular termini were obtained. The clinical machines overestimated bone volume and trabecular thickness and underestimated trabecular nodes and number, but cone-beam CT to a lesser extent. Parameters obtained from cone beam CT were strongly correlated with μCT, with correlation coefficients between 0.93 and 0.98 for all parameters except trabecular termini. The high correlation between cone-beam CT and micro-CT suggest the possibility of quantifying and monitoring changes of trabecular bone microarchitecture in vivo using cone beam CT. (orig.)

Multi-scale X-ray computed tomography to detect and localize metal-based nanomaterials in lung tissues of in vivo exposed mice.

Science.gov (United States)

Chaurand, Perrine; Liu, Wei; Borschneck, Daniel; Levard, Clément; Auffan, Mélanie; Paul, Emmanuel; Collin, Blanche; Kieffer, Isabelle; Lanone, Sophie; Rose, Jérôme; Perrin, Jeanne

2018-03-13

In this methodological study, we demonstrated the relevance of 3D imaging performed at various scales for the ex vivo detection and location of cerium oxide nanomaterials (CeO 2 -NMs) in mouse lung. X-ray micro-computed tomography (micro-CT) with a voxel size from 14 µm to 1 µm (micro-CT) was combined with X-ray nano-computed tomography with a voxel size of 63 nm (nano-CT). An optimized protocol was proposed to facilitate the sample preparation, to minimize the experimental artifacts and to optimize the contrast of soft tissues exposed to metal-based nanomaterials (NMs). 3D imaging of the NMs biodistribution in lung tissues was consolidated by combining a vast variety of techniques in a correlative approach: histological observations, 2D chemical mapping and speciation analysis were performed for an unambiguous detection of NMs. This original methodological approach was developed following a worst-case scenario of exposure, i.e. high dose of exposure with administration via intra-tracheal instillation. Results highlighted both (i) the non-uniform distribution of CeO 2 -NMs within the entire lung lobe (using large field-of-view micro-CT) and (ii) the detection of CeO 2 -NMs down to the individual cell scale, e.g. macrophage scale (using nano-CT with a voxel size of 63 nm).

Pore formation during dehydration of a polycrystalline gypsum sample observed and quantified in a time-series synchrotron X-ray micro-tomography experiment

Directory of Open Access Journals (Sweden)

F. Fusseis

2012-03-01

Full Text Available We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comprising nine time steps. The voxel size of 2.2 μm³ proved sufficient to pinpoint reaction initiation and the organization of drainage architecture in space and time.

We observed that dehydration commences across a narrow front, which propagates from the margins to the centre of the sample in more than four hours. The advance of this front can be fitted with a square-root function, implying that the initiation of the reaction in the sample can be described as a diffusion process.

Novel parallelized computer codes allow quantifying the geometry of the porosity and the drainage architecture from the very large tomographic datasets (2048³ voxels in unprecedented detail. We determined position, volume, shape and orientation of each resolvable pore and tracked these properties over the duration of the experiment. We found that the pore-size distribution follows a power law. Pores tend to be anisotropic but rarely crack-shaped and have a preferred orientation, likely controlled by a pre-existing fabric in the sample. With on-going dehydration, pores coalesce into a single interconnected pore cluster that is connected to the surface of the sample cylinder and provides an effective drainage pathway.

Our observations can be summarized in a model in which gypsum is stabilized by thermal expansion stresses and locally increased pore fluid pressures until the dehydration front approaches to within about 100 μm. Then, the internal stresses are released and dehydration happens efficiently, resulting in new pore space. Pressure release, the production of pores and the

Pore formation during dehydration of polycrystalline gypsum observed and quantified in a time-series synchrotron radiation based X-ray micro-tomography experiment

Science.gov (United States)

Fusseis, F.; Schrank, C.; Liu, J.; Karrech, A.; Llana-Fúnez, S.; Xiao, X.; Regenauer-Lieb, K.

2011-10-01

We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA) to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comprising nine time steps. The voxel size of 2.2 μm3 proved sufficient to pinpoint reaction initiation and the organization of drainage architecture in space and time. We observed that dehydration commences across a narrow front, which propagates from the margins to the centre of the sample in more than four hours. The advance of this front can be fitted with a square-root function, implying that the initiation of the reaction in the sample can be described as a diffusion process. Novel parallelized computer codes allow quantifying the geometry of the porosity and the drainage architecture from the very large tomographic datasets (6.4 × 109 voxel each) in unprecedented detail. We determined position, volume, shape and orientation of each resolvable pore and tracked these properties over the duration of the experiment. We found that the pore-size distribution follows a power law. Pores tend to be anisotropic but rarely crack-shaped and have a preferred orientation, likely controlled by a pre-existing fabric in the sample. With on-going dehydration, pores coalesce into a single interconnected pore cluster that is connected to the surface of the sample cylinder and provides an effective drainage pathway. Our observations can be summarized in a model in which gypsum is stabilized by thermal expansion stresses and locally increased pore fluid pressures until the dehydration front approaches to within about 100 μm. Then, the internal stresses are released and dehydration happens efficiently, resulting in new pore space. Pressure release, the production of pores and the advance of the front are coupled in a feedback loop. We

Pore formation during dehydration of a polycrystalline gypsum sample observed and quantified in a time-series synchrotron X-ray micro-tomography experiment

Science.gov (United States)

Fusseis, F.; Schrank, C.; Liu, J.; Karrech, A.; Llana-Fúnez, S.; Xiao, X.; Regenauer-Lieb, K.

2012-03-01

We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA) to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comprising nine time steps. The voxel size of 2.2 μm3 proved sufficient to pinpoint reaction initiation and the organization of drainage architecture in space and time. We observed that dehydration commences across a narrow front, which propagates from the margins to the centre of the sample in more than four hours. The advance of this front can be fitted with a square-root function, implying that the initiation of the reaction in the sample can be described as a diffusion process. Novel parallelized computer codes allow quantifying the geometry of the porosity and the drainage architecture from the very large tomographic datasets (20483 voxels) in unprecedented detail. We determined position, volume, shape and orientation of each resolvable pore and tracked these properties over the duration of the experiment. We found that the pore-size distribution follows a power law. Pores tend to be anisotropic but rarely crack-shaped and have a preferred orientation, likely controlled by a pre-existing fabric in the sample. With on-going dehydration, pores coalesce into a single interconnected pore cluster that is connected to the surface of the sample cylinder and provides an effective drainage pathway. Our observations can be summarized in a model in which gypsum is stabilized by thermal expansion stresses and locally increased pore fluid pressures until the dehydration front approaches to within about 100 μm. Then, the internal stresses are released and dehydration happens efficiently, resulting in new pore space. Pressure release, the production of pores and the advance of the front are coupled in a feedback loop.

A quality assurance phantom for the performance evaluation of volumetric micro-CT systems

Energy Technology Data Exchange (ETDEWEB)

Du, Louise Y [Department of Medical Biophysics, University of Western Ontario, London, ON (Canada); Umoh, Joseph [Imaging Research Laboratories, Robarts Research Institute, London, ON (Canada); Nikolov, Hristo N [Imaging Research Laboratories, Robarts Research Institute, London, ON (Canada); Pollmann, Steven I [Imaging Research Laboratories, Robarts Research Institute, London, ON (Canada); Lee, Ting-Yim [Department of Medical Biophysics, University of Western Ontario, London, ON (Canada); Holdsworth, David W [Department of Medical Biophysics, University of Western Ontario, London, ON (Canada)

2007-12-07

Small-animal imaging has recently become an area of increased interest because more human diseases can be modeled in transgenic and knockout rodents. As a result, micro-computed tomography (micro-CT) systems are becoming more common in research laboratories, due to their ability to achieve spatial resolution as high as 10 {mu}m, giving highly detailed anatomical information. Most recently, a volumetric cone-beam micro-CT system using a flat-panel detector (eXplore Ultra, GE Healthcare, London, ON) has been developed that combines the high resolution of micro-CT and the fast scanning speed of clinical CT, so that dynamic perfusion imaging can be performed in mice and rats, providing functional physiological information in addition to anatomical information. This and other commercially available micro-CT systems all promise to deliver precise and accurate high-resolution measurements in small animals. However, no comprehensive quality assurance phantom has been developed to evaluate the performance of these micro-CT systems on a routine basis. We have designed and fabricated a single comprehensive device for the purpose of performance evaluation of micro-CT systems. This quality assurance phantom was applied to assess multiple image-quality parameters of a current flat-panel cone-beam micro-CT system accurately and quantitatively, in terms of spatial resolution, geometric accuracy, CT number accuracy, linearity, noise and image uniformity. Our investigations show that 3D images can be obtained with a limiting spatial resolution of 2.5 mm{sup -1} and noise of {+-}35 HU, using an acquisition interval of 8 s at an entrance dose of 6.4 cGy.

A quality assurance phantom for the performance evaluation of volumetric micro-CT systems

International Nuclear Information System (INIS)

Du, Louise Y; Umoh, Joseph; Nikolov, Hristo N; Pollmann, Steven I; Lee, Ting-Yim; Holdsworth, David W

2007-01-01

Small-animal imaging has recently become an area of increased interest because more human diseases can be modeled in transgenic and knockout rodents. As a result, micro-computed tomography (micro-CT) systems are becoming more common in research laboratories, due to their ability to achieve spatial resolution as high as 10 μm, giving highly detailed anatomical information. Most recently, a volumetric cone-beam micro-CT system using a flat-panel detector (eXplore Ultra, GE Healthcare, London, ON) has been developed that combines the high resolution of micro-CT and the fast scanning speed of clinical CT, so that dynamic perfusion imaging can be performed in mice and rats, providing functional physiological information in addition to anatomical information. This and other commercially available micro-CT systems all promise to deliver precise and accurate high-resolution measurements in small animals. However, no comprehensive quality assurance phantom has been developed to evaluate the performance of these micro-CT systems on a routine basis. We have designed and fabricated a single comprehensive device for the purpose of performance evaluation of micro-CT systems. This quality assurance phantom was applied to assess multiple image-quality parameters of a current flat-panel cone-beam micro-CT system accurately and quantitatively, in terms of spatial resolution, geometric accuracy, CT number accuracy, linearity, noise and image uniformity. Our investigations show that 3D images can be obtained with a limiting spatial resolution of 2.5 mm -1 and noise of ±35 HU, using an acquisition interval of 8 s at an entrance dose of 6.4 cGy

Micro-computed tomography (CT) based assessment of dental regenerative therapy in the canine mandible model

Science.gov (United States)

Khobragade, P.; Jain, A.; Setlur Nagesh, S. V.; Andreana, S.; Dziak, R.; Sunkara, S. K.; Sunkara, S.; Bednarek, D. R.; Rudin, S.; Ionita, C. N.

2015-03-01

High-resolution 3D bone-tissue structure measurements may provide information critical to the understanding of the bone regeneration processes and to the bone strength assessment. Tissue engineering studies rely on such nondestructive measurements to monitor bone graft regeneration area. In this study, we measured bone yield, fractal dimension and trabecular thickness through micro-CT slices for different grafts and controls. Eight canines underwent surgery to remove a bone volume (defect) in the canine's jaw at a total of 44 different locations. We kept 11 defects empty for control and filled the remaining ones with three regenerative materials; NanoGen (NG), a FDA-approved material (n=11), a novel NanoCalcium Sulfate (NCS) material (n=11) and NCS alginate (NCS+alg) material (n=11). After a minimum of four and eight weeks, the canines were sacrificed and the jaw samples were extracted. We used a custombuilt micro-CT system to acquire the data volume and developed software to measure the bone yield, fractal dimension and trabecular thickness. The software used a segmentation algorithm based on histograms derived from volumes of interest indicated by the operator. Using bone yield and fractal dimension as indices we are able to differentiate between the control and regenerative material (p<0.005). Regenerative material NCS showed an average 63.15% bone yield improvement over the control sample, NCS+alg showed 55.55% and NanoGen showed 37.5%. The bone regeneration process and quality of bone were dependent upon the position of defect and time period of healing. This study presents one of the first quantitative comparisons using non-destructive Micro-CT analysis for bone regenerative material in a large animal with a critical defect model. Our results indicate that Micro-CT measurement could be used to monitor invivo bone regeneration studies for greater regenerative process understanding.

A Bipolar Spindle of Antiparallel ParM Filaments Drives Bacterial Plasmid Segregation

DEFF Research Database (Denmark)

Gayathri, P; Fujii, T; Møller-Jensen, Jakob

2012-01-01

the spindle between ParRC complexes on sister plasmids. Using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins. The architecture...... of ParM filaments enabled two ParRC-bound filaments to associate in an antiparallel orientation, forming a bipolar spindle. The spindle elongated as a bundle of at least two antiparallel filaments, thereby pushing two plasmid clusters toward the poles....

Long-term Risedronate Treatment Normalizes Mineralization and Continues to Preserve Trabecular Architecture: Sequential Triple Biopsy Studies with Micro-Computed Tomography

International Nuclear Information System (INIS)

Borah, B.; Dufresne, T.; Ritman, E.; Jorgensen, S.; Liu, S.; Chmielewski, P.; Phipps, R.; Zhou, X.; Sibonga, J.; Turner, R.

2006-01-01

The objective of the study was to assess the time course of changes in bone mineralization and architecture using sequential triple biopsies from women with postmenopausal osteoporosis (PMO) who received long-term treatment with risedronate. Transiliac biopsies were obtained from the same subjects (n = 7) at baseline and after 3 and 5 years of treatment with 5 mg daily risedronate. Mineralization was measured using 3-dimensional (3D) micro-computed tomography (CT) with synchrotron radiation and was compared to levels in healthy premenopausal women (n = 12). Compared to the untreated PMO women at baseline, the premenopausal women had higher average mineralization (Avg-MIN) and peak mineralization (Peak-MIN) by 5.8% (P = 0.003) and 8.0% (P = 0.003), respectively, and lower ratio of low to high-mineralized bone volume (BMR-V) and surface area (BMR-S) by 73.3% (P = 0.005) and 61.7% (P 0.003), respectively. Relative to baseline, 3 years of risedronate treatment significantly increased Avg-MIN (4.9 ± 1.1%, P = 0.016) and Peak-MIN (6.2 ± 1.5%, P = 0.016), and significantly decreased BMR-V (-68.4 ± 7.3%, P = 0.016) and BMR-S (-50.2 ± 5.7%, P = 0.016) in the PMO women. The changes were maintained at the same level when treatment was continued up to 5 years. These results are consistent with the significant reduction of turnover observed after 3 years of treatment and which was similarly maintained through 5 years of treatment. Risedronate restored the degree of mineralization and the ratios of low- to high-mineralized bone to premenopausal levels after 3 years of treatment, suggesting that treatment reduced bone turnover in PMO women to healthy premenopausal levels. Conventional micro-CT analysis further demonstrated that bone volume (BV/TV) and trabecular architecture did not change from baseline up to 5 years of treatment, suggesting that risedronate provided long-term preservation of trabecular architecture in the PMO women. Overall, risedronate provided sustained

Search for Bs0 --> micro+ micro- and B0 --> micro+ micro- decays with 2 fb-1 of pp collisions.

Science.gov (United States)

Aaltonen, T; Adelman, J; Akimoto, T; Albrow, M G; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Bednar, P; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'orso, M; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Genser, K; Gerberich, H; Gerdes, D; Giagu, S; Giakoumopolou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Koay, S A; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lu, R-S; Lucchesi, D; Lueck, J; Luci, C; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyria, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner-Kuhr, J; Wagner, W; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zheng, Y; Zucchelli, S

2008-03-14

We have performed a search for B(s)(0) --> micro(+) micro(-) and B(0) --> micro(+) micro(-) decays in pp collisions at square root s = 1.96 TeV using 2 fb(-1) of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron Collider. The observed number of B(s)(0) and B0 candidates is consistent with background expectations. The resulting upper limits on the branching fractions are B(B(s)0) --> micro(+) micro(-)) micro(+) micro(-))<1.8 x 10(-8) at 95% C.L.

PAR-2 expression in the gingival crevicular fluid reflects chronic periodontitis severity

Directory of Open Access Journals (Sweden)

Henrique FUKUSHIMA

Full Text Available Abstract Recent studies investigating protease-activated receptor type 2 (PAR-2 suggest an association between the receptor and periodontal inflammation. It is known that gingipain, a bacterial protease secreted by the important periodontopathogen Porphyromonas gingivalis can activate PAR-2. Previous studies by our group found that PAR-2 is overexpressed in the gingival crevicular fluid (GCF of patients with moderate chronic periodontitis (MP. The present study aimed at evaluating whether PAR-2 expression is associated with chronic periodontitis severity. GCF samples and clinical parameters, including plaque and bleeding on probing indices, probing pocket depth and clinical attachment level, were collected from the control group (n = 19 at baseline, and from MP patients (n = 19 and severe chronic periodontitis (SP (n = 19 patients before and 6 weeks after periodontal non-surgical treatment. PAR-2 and gingipain messenger RNA (mRNA in the GCF of 4 periodontal sites per patient were evaluated by Reverse Transcription Polymerase Chain Reaction (RT-qPCR. PAR-2 and gingipain expressions were greater in periodontitis patients than in control group patients. In addition, the SP group presented increased PAR-2 and gingipain mRNA levels, compared with the MP group. Furthermore, periodontal treatment significantly reduced (p <0.05 PAR-2 expression in patients with periodontitis. In conclusion, PAR-2 is associated with chronic periodontitis severity and with gingipain levels in the periodontal pocket, thus suggesting that PAR-2 expression in the GCF reflects the severity of destruction during periodontal infection.

Cone-Beam Computed Tomography for Image-Guided Radiation Therapy of Prostate Cancer

Science.gov (United States)

2008-01-01

imaging in small- animal on-Medical Physics, Vol. 34, No. 12, December 2007cology models,” Mol. Imag. 3, 55–62 2004. 8E. B. Walters, K. Panda , J. A...publication 8 October 2007; published 28 November 2007 Cone-beam microcomputed tomography microCT is one of the most popular choices for small animal ...imaging which is becoming an important tool for studying animal models with transplanted diseases. Region-of-interest ROI imaging techniques in CT, which

Structures of actin-like ParM filaments show architecture of plasmid-segregating spindles.

Science.gov (United States)

Bharat, Tanmay A M; Murshudov, Garib N; Sachse, Carsten; Löwe, Jan

2015-07-02

Active segregation of Escherichia coli low-copy-number plasmid R1 involves formation of a bipolar spindle made of left-handed double-helical actin-like ParM filaments. ParR links the filaments with centromeric parC plasmid DNA, while facilitating the addition of subunits to ParM filaments. Growing ParMRC spindles push sister plasmids to the cell poles. Here, using modern electron cryomicroscopy methods, we investigate the structures and arrangements of ParM filaments in vitro and in cells, revealing at near-atomic resolution how subunits and filaments come together to produce the simplest known mitotic machinery. To understand the mechanism of dynamic instability, we determine structures of ParM filaments in different nucleotide states. The structure of filaments bound to the ATP analogue AMPPNP is determined at 4.3 Å resolution and refined. The ParM filament structure shows strong longitudinal interfaces and weaker lateral interactions. Also using electron cryomicroscopy, we reconstruct ParM doublets forming antiparallel spindles. Finally, with whole-cell electron cryotomography, we show that doublets are abundant in bacterial cells containing low-copy-number plasmids with the ParMRC locus, leading to an asynchronous model of R1 plasmid segregation.

Par and IR reflectance, transmittance, and absorptance of four crop canopies

International Nuclear Information System (INIS)

Wanjura, D.F.; Hatfield, J.L.

1986-01-01

Reflectance, transmittance and absorptance of electromagnetic radiation by cotton, soybeans, grain sorghum, and sunflower was measured at three growth stages in two wavebands (PAR: 0.4 to 0.7 pun and IR: 0.7 to 1.1 yim). As leaf area increased in each crop there were increases in IR reflectance and PAR absorptance and decreases in PAR reflectance and both PAR and IR transmittance. IR radiation was concentrated at the soil surface between rows by reflectance from the sides of canopies when crop cover was less than 80%. Across all crops one parameter, leaf overlap index, explained 81 and 71% of the PAR reflectance and another, crop cover, explained 86 and 94% of IR reflectance from rows and interrows, respectively. Attenuation of PAR radiation through the canopies of cotton and sunflower was similar (K = 0.62 and 0.67) but different from that of soybeans and grain sorghum (K = 0.46 and 0.43) which were the same

MicroED data collection and processing

Energy Technology Data Exchange (ETDEWEB)

Hattne, Johan; Reyes, Francis E.; Nannenga, Brent L.; Shi, Dan; Cruz, M. Jason de la [Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147 (United States); Leslie, Andrew G. W. [Medical Research Council Laboratory of Molecular Biology, Cambridge (United Kingdom); Gonen, Tamir, E-mail: gonent@janelia.hhmi.org [Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147 (United States)

2015-07-01

The collection and processing of MicroED data are presented. MicroED, a method at the intersection of X-ray crystallography and electron cryo-microscopy, has rapidly progressed by exploiting advances in both fields and has already been successfully employed to determine the atomic structures of several proteins from sub-micron-sized, three-dimensional crystals. A major limiting factor in X-ray crystallography is the requirement for large and well ordered crystals. By permitting electron diffraction patterns to be collected from much smaller crystals, or even single well ordered domains of large crystals composed of several small mosaic blocks, MicroED has the potential to overcome the limiting size requirement and enable structural studies on difficult-to-crystallize samples. This communication details the steps for sample preparation, data collection and reduction necessary to obtain refined, high-resolution, three-dimensional models by MicroED, and presents some of its unique challenges.

Épidémiologie de l'intoxication par envenimation chez les enfants ...

African Journals Online (AJOL)

Introduction: L'intoxication par envenimation est l'ensemble des manifestations locales et générales induites par la pénétration dans l'organisme d'une substance toxique produite par un animal venimeux. Le but de notre travail était d'étudier les signes cliniques des intoxications par envenimation chez les enfants de 0 à 15 ...

PARs for combustible gas control in advanced light water reactors

International Nuclear Information System (INIS)

Hosler, J.; Sliter, G.

1997-01-01

This paper discusses the progress being made in the United States to introduce passive autocatalytic recombiner (PAR) technology as a cost-effective alternative to electric recombiners for controlling combustible gas produced in postulated accidents in both future Advanced Light Water Reactors (ALWRs) and certain U. S. operating nuclear plants. PARs catalytically recombine hydrogen and oxygen, gradually producing heat and water vapor. They have no moving parts and are self-starting and self-feeding, even under relatively cold and wet containment conditions. Buoyancy of the hot gases they create sets up natural convective flow that promotes mixing of combustible gases in a containment. In a non-inerted ALWR containment, two approaches each employing a combination of PARs and igniters are being considered to control hydrogen in design basis and severe accidents. In pre-inerted ALWRs, PARs alone control radiolytic oxygen produced in either accident type. The paper also discusses regulatory feedback regarding these combustible gas control approaches and describes a test program being conducted by the Electric Power Research Institute (EPRI) and Electricite de France (EdF) to supplement the existing PAR test database with performance data under conditions of interest to U.S. plants. Preliminary findings from the EPRI/EdF PAR model test program are included. Successful completion of this test program and confirmatory tests being sponsored by the U. S. NRC are expected to pave the way for use of PARs in ALWRs and operating plants. (author)

Micro-propulsion and micro-combustion; Micropropulsion microcombustion

Energy Technology Data Exchange (ETDEWEB)

Ribaud, Y.; Dessornes, O.

2002-10-01

The AAAF (french space and aeronautic association) organized at Paris a presentation on the micro-propulsion. The first part was devoted to the thermal micro-machines for micro drones, the second part to the micro-combustion applied to micro-turbines. (A.L.B.)

Present and future in the use of micro-CT scanner 3D analysis for the study of dental and root canal morphology

OpenAIRE

Nicola M. Grande; Gianluca Plotino; Gianluca Gambarini; Luca Testarelli; Ferdinando D’Ambrosio; Raffaella Pecci; Rossella Bedini

2012-01-01

The goal of the present article is to illustrate and analyze the applications and the potential of microcomputed tomography (micro-CT) in the analysis of tooth anatomy and root canal morphology. The authors performed a micro-CT analysis of the following different teeth: maxillary first molars with a second canal in the mesiobuccal (MB) root, mandibular first molars with complex anatomy in the mesial root, premolars with single and double roots and with complicated apical anatomy. The hardware...

A Micro-computed Tomography Evaluation of the Shaping Ability of Two Nickel-titanium Instruments, HyFlex EDM and ProTaper Next.

Science.gov (United States)

Venino, Pier Matteo; Citterio, Claudio Luigi; Pellegatta, Alberto; Ciccarelli, Marta; Maddalone, Marcello

2017-04-01

The aim of this study was to evaluate and compare, by means of micro-computed tomography imaging, the shaping ability of ProTaper Next (PTN) and the novel HyFlex EDM (HFEDM) instruments. Forty teeth were randomly divided into 2 groups and prepared with PTN or HFEDM. Root canal transportation and centering ratio were evaluated in mesiodistal and buccolingual directions at 5 levels (at the midpoint of the apical, middle, and coronal thirds and at the boundaries between them). Variations in volume, surface, and cross-sectional shape were measured for the apical, middle, and coronal thirds. The null hypotheses were that no differences existed between the 2 groups. The D'Agostino-Pearson test (α = .05) was conducted to assess the normality of the data sets. The distributions were compared by using the Mann-Whitney test (α = .05). Statistically significant differences (P < .005) were recorded only for buccolingual canal transportation and centering ratio at the section between the middle and coronal thirds, where HFEDM files were superior. HFEDM and PTN files were similarly effective, and both safely prepared the root canals, respecting their original anatomies. HFEDM files performed better in terms of buccolingual canal transportation and centering ratio at the section between the middle and coronal thirds. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Experimental Study on Bioluminescence Tomography with Multimodality Fusion

Directory of Open Access Journals (Sweden)

Yujie Lv

2007-01-01

Full Text Available To verify the influence of a priori information on the nonuniqueness problem of bioluminescence tomography (BLT, the multimodality imaging fusion based BLT experiment is performed by multiview noncontact detection mode, which incorporates the anatomical information obtained by the microCT scanner and the background optical properties based on diffuse reflectance measurements. In the reconstruction procedure, the utilization of adaptive finite element methods (FEMs and a priori permissible source region refines the reconstructed results and improves numerical robustness and efficiency. The comparison between the absence and employment of a priori information shows that multimodality imaging fusion is essential to quantitative BLT reconstruction.

Brulure par Plaque de Bistouri Electrique: a Propos de Quatre Cas

Science.gov (United States)

Khales, A.; Achbouk, A.; Belmir, R.; Cherkab, L.; Ennouhi, M.A.; Ababou, K.; Ihrai, H.

2010-01-01

Summary La brûlure par plaque de bistouri électrique est un accident rare mais grave par la profondeur de la lésion et par sa localisation, surtout quand qu’elle survient dans un contexte chirurgical dont le vécu reste difficile de la part du malade et du chirurgien. Cette brûlure bien que imprévisible reste grave par la profondeur et la localisation de la brûlure et par sa survenue dans un contexte opératoire, chez des patients malades. La prise en charge de la brûlure doit se faire en milieu spécialisé. La prévention reste le seul moyen d’éviter ce type d’accident. PMID:21991216

Accuracy of volumetric measurement of simulated root resorption lacunas based on cone beam computed tomography.

Science.gov (United States)

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.

Elusloom lennukiga puhkusele / Inge Parring

Index Scriptorium Estoniae

Parring, Inge

2003-01-01

Ilmunud ka: Delovõje Vedomosti 1. okt. lk. 13. Air Cargo Estonia/ACE Logisticsi müügijuht Inge Parring tutvustab elusloomade transpordivõimalusi. Vt. samas: Loomade transportimiseks vajalikud dokumendid

suPAR

DEFF Research Database (Denmark)

Eugen-Olsen, Jesper; Giamarellos-Bourboulis, Evangelos J

2015-01-01

Investigation of biomarkers that can promptly predict unfavourable outcome of critically illness is an emerging necessity taking into consideration the need for early intervention, the shortage of available beds in intensive care units and the considerable cost of hospitalisation. The most...... promising biomarker is soluble urokinase-type plasminogen activator receptor (suPAR). Three studies in large populations of critically ill patients and patients admitted to the emergency department have shown that concentrations >12ng/mL can safely predict unfavourable outcome. This review presents...

Urine suPAR levels compared with plasma suPAR levels as predictors of post-consultation mortality risk among individuals assumed to be TB-negative: a prospective cohort study

DEFF Research Database (Denmark)

Rabna, Paulo; Andersen, Andreas; Wejse, Christian

2010-01-01

-suPAR was measured using a commercial ELISA (suPARnostic®). We found that U-suPAR carried significant prognostic information on mortality for HIV-infected subjects with an area under the ROC curve of 0.75. For HIV-negative individuals, little or no prognostic effect was observed. However, in both HIV positives...... and negatives, the predictive effect of U-suPAR was found to be inferior to that of P-suPAR....

Brésil : La contamination par le mercure en Amazonie | CRDI ...

International Development Research Centre (IDRC) Digital Library (Canada)

11 janv. 2011 ... En tentant de déceler la source de la contamination de l'Amazone par le ... par Jean-Rémy Davy Guimaraes de l'Université fédérale de Rio de Janeiro ... ces mattes est circonscrite par la conservation et la restauration en rive.

Development of in-vivo micro CT system for small animals

Energy Technology Data Exchange (ETDEWEB)

Nam, Ki Yong; Lim, Jong Hyeok; Jeong, Young Jo; Park, Jeong Gwon [Institute for Radiological Imaging Science, Iksan (Korea, Republic of); Park, Jung Bung [DRGEM Corp., Seoul (Korea, Republic of); Yoon, Kwon Ha [Institute for Radiological Imaging Science and Medical School of Radiology, Iksan (Korea, Republic of)

2005-07-01

Computed tomography system with the spatial resolution of {approx}25 {mu}m has been developed for the application to small animals. This system is designed by gantry-rotation type for minimizing animal movement. To get image with micro-spatial resolution, system characteristic such as geometry between main components of source, specimen and detector, field of view, etc., is described in this paper. The requirements of x-ray spot size and CCD pixel size to approach the resolution are discussed. In-vivo imaging test for mouse is also presented as a result.

Development of in-vivo micro CT system for small animals

International Nuclear Information System (INIS)

Nam, Ki Yong; Lim, Jong Hyeok; Jeong, Young Jo; Park, Jeong Gwon; Park, Jung Bung; Yoon, Kwon Ha

2005-01-01

Computed tomography system with the spatial resolution of ∼25 μm has been developed for the application to small animals. This system is designed by gantry-rotation type for minimizing animal movement. To get image with micro-spatial resolution, system characteristic such as geometry between main components of source, specimen and detector, field of view, etc., is described in this paper. The requirements of x-ray spot size and CCD pixel size to approach the resolution are discussed. In-vivo imaging test for mouse is also presented as a result

Quantitative analysis of titanium-induced artifacts and correlated factors during micro-CT scanning.

Science.gov (United States)

Li, Jun Yuan; Pow, Edmond Ho Nang; Zheng, Li Wu; Ma, Li; Kwong, Dora Lai Wan; Cheung, Lim Kwong

2014-04-01

To investigate the impact of cover screw, resin embedment, and implant angulation on artifact of microcomputed tomography (micro-CT) scanning for implant. A total of twelve implants were randomly divided into 4 groups: (i) implant only; (ii) implant with cover screw; (iii) implant with resin embedment; and (iv) implants with cover screw and resin embedment. Implants angulation at 0°, 45°, and 90° were scanned by micro-CT. Images were assessed, and the ratio of artifact volume to total volume (AV/TV) was calculated. A multiple regression analysis in stepwise model was used to determine the significance of different factors. One-way ANOVA was performed to identify which combination of factors could minimize the artifact. In the regression analysis, implant angulation was identified as the best predictor for artifact among the factors (P  0.05). Non-embedded implants with the axis parallel to X-ray source of micro-CT produced minimal artifact. Implant angulation and resin embedment affected the artifact volume of micro-CT scanning for implant, while cover screw did not. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

On-chip micro-power: three-dimensional structures for micro-batteries and micro-supercapacitors

Science.gov (United States)

Beidaghi, Majid; Wang, Chunlei

2010-04-01

With the miniaturization of portable electronic devices, there is a demand for micro-power source which can be integrated on the semiconductor chips. Various micro-batteries have been developed in recent years to generate or store the energy that is needed by microsystems. Micro-supercapacitors are also developed recently to couple with microbatteries and energy harvesting microsystems and provide the peak power. Increasing the capacity per footprint area of micro-batteries and micro-supercapacitors is a great challenge. One promising route is the manufacturing of three dimensional (3D) structures for these micro-devices. In this paper, the recent advances in fabrication of 3D structure for micro-batteries and micro-supercapacitors are briefly reviewed.

Three-dimensional densitometry imaging of diatom cells using STIM tomography

International Nuclear Information System (INIS)

Habchi, C.; Nguyen, D.T.; Deves, G.; Incerti, S.; Lemelle, L.; Van Vang, P. Le; Moretto, Ph.; Ortega, R.; Seznec, H.; Sakellariou, A.; Sergeant, C.; Simionovici, A.; Ynsa, M.D.; Gontier, E.; Heiss, M.; Pouthier, T.; Boudou, A.; Rebillat, F.

2006-01-01

Scanning transmission ion microscopy tomography (STIM-T) was carried out on diatom cells with the aim of displaying their 3D structure and performing density measurements on their silica skeleton. Two software packages were compared for data reduction: TomoRebuild, based on a simple filtered backprojection algorithm, and DISRA, an iterative program. Silicon carbide microfibres of known density were also analysed as reference specimens. Similar results were obtained with both algorithms, demonstrating the ability of STIM-T to provide density measurements at the cell level without requiring any standard calibration samples. This unique feature stresses the interest of STIM-T to accurately normalise X ray emission micro-tomography data from synchrotron radiation (SXRF: synchrotron radiation X-ray fluorescence) or ion beam sources (PIXE: particle induced X-ray emission). Possible enhancements of the DISRA code are discussed in order to facilitate its use for the reconstruction of future PIXE/STIM tomography data. A 'nanoprobe' coupled to a Singletron[reg] accelerator, allowing a spatial resolution of a few tens of nanometers, is going to be built in the coming months at the Centre d'Etudes Nucleaires de Bordeaux Gradignan (CENBG). This new facility will bring promising applications in imaging and analysis at the sub-cellular level

Experimental contamination of margaritana margaritifera (L) (a Fresh water bivalve) by caesium 137; Contamination experimentale de margaritana margaritifera (L) (bivalve d'eau douce) par le cesium 137

Energy Technology Data Exchange (ETDEWEB)

Foulquier, L; Bovard, P; Grauby, A [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

1966-07-01

The hydro biological research carried out in the Radio-Ecology Section has led the authors to study some Margaritana sampling stations situated down-stream from the Monts d'Arree nuclear power station. They describe the preservation and contamination methods used for fixing the {sup 137}Cs concentration factors in the case of Margaritana Margaritifera (L). The results of experiments carried out over a period of one hundred days show that the specific activity of the various organs is stabilized after thirty to thirty-five days. The authors have noticed a relatively low adsorption on the shell through the intermediary of micro-organisms, and a strong and rapid absorption in the soft parts. The concentration factors have values, at equilibrium, of around: 9 for the shell, 300 for all the organs, and 38 for the whole animal. A comparison of these results with work published by other authors makes it possible to draw general conclusions concerning the mechanism of {sup 137}Cs fixation by lamellibranch, as well as their capacity of fixation. (author) [French] Les etudes hydrobiologiques effectuees au sein de la Section de Radio-Ecologie ont amene les auteurs a etudier des stations de prelevement de Margaritana en aval de la Centrale Nucleaire des Monts d'Arree. Ils decrivent les methodes de conservation et de contamination utilisees pour l'etablissement des facteurs de concentration du {sup 137}Cs par Margaritana margaritifera (L). Les resultats des experimentations menees pendant cent jours montrent que les activites specifiques de la coquille et des differents organes se stabilisent au bout de trente a trente-cinq jours. Les auteurs constatent une adsorption relativement faible sur la coquille par l'intermediaire des micro-organismes et une absorption forte et rapide dans les parties molles. Les facteurs de concentration se situent, a l'equilibre, autour de: 9 pour la coquille, 300 pour l'ensemble des organes et 38 si l'on considere l'animal total. Cette etude

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.

Science.gov (United States)

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

Electron microscope study of vacancy clusters produced by quenching in magnesium; Etude par microscopie electronique des amas de lacunes crees par trempe dans le magnesium

Energy Technology Data Exchange (ETDEWEB)

Levy, V; Espinasse, J; Mairy, C; Hillairet, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

Vacancy clustering in quenched magnesium has been studied by transmission electron microscopy. The nature of the vacancy loops observed, seems to depend essentially on the impurity content of the metal; this effect can be attributed to a variation of the stacking fault energy of magnesium due to impurities. (authors) [French] On a etudie par microscopie electronique en transmission les defauts crees par trempe dans le magnesium. Un effet considerable des impuretes du metal sur la nature des boucles obtenues par condensation de lacunes a ete mis en evidence; cet effet semble s'expliquer de facon satisfaisante par un abaissement de l'energie de faute d'empilement du magnesium du aux impuretes. (auteur)

ParABS Systems of the Four Replicons of Burkholderia cenocepacia: New Chromosome Centromeres Confer Partition Specificity†

Science.gov (United States)

Dubarry, Nelly; Pasta, Franck; Lane, David

2006-01-01

Most bacterial chromosomes carry an analogue of the parABS systems that govern plasmid partition, but their role in chromosome partition is ambiguous. parABS systems might be particularly important for orderly segregation of multipartite genomes, where their role may thus be easier to evaluate. We have characterized parABS systems in Burkholderia cenocepacia, whose genome comprises three chromosomes and one low-copy-number plasmid. A single parAB locus and a set of ParB-binding (parS) centromere sites are located near the origin of each replicon. ParA and ParB of the longest chromosome are phylogenetically similar to analogues in other multichromosome and monochromosome bacteria but are distinct from those of smaller chromosomes. The latter form subgroups that correspond to the taxa of their hosts, indicating evolution from plasmids. The parS sites on the smaller chromosomes and the plasmid are similar to the “universal” parS of the main chromosome but with a sequence specific to their replicon. In an Escherichia coli plasmid stabilization test, each parAB exhibits partition activity only with the parS of its own replicon. Hence, parABS function is based on the independent partition of individual chromosomes rather than on a single communal system or network of interacting systems. Stabilization by the smaller chromosome and plasmid systems was enhanced by mutation of parS sites and a promoter internal to their parAB operons, suggesting autoregulatory mechanisms. The small chromosome ParBs were found to silence transcription, a property relevant to autoregulation. PMID:16452432

MicroCT Scan in paleobiology: application to the study of dental tissues

Energy Technology Data Exchange (ETDEWEB)

Rossi, M.; Casali, F. E-mail: casali@bo.infn.it; Romani, D.; Bondioli, L.; Macchiarelli, R.; Rook, L

2004-01-01

State of the art in paleoanthropological and paleoprimatological research foresees the use of advanced non-destructive investigative approaches. Microcomputed tomography (microCT) is a fundamental tool, since it offers the opportunity to get high quality morphological information with high spatial resolution. We carried out the set-up of an experimental microCT system able to examine paleobiological samples. The equipment can operate on small objects (size up to 3 cm) with a nominal spatial resolution of 30 {mu}m, allowing their 3D volume reconstruction and morphometric analysis. This approach represents a forefront technique in paleobiological studies, successfully employed only in a limited number of advanced research centers. A specific program of microCT analysis has been planned on a sample of human and non-human fossil primate dentitions, in order to assess the specific nature of a number of tooth lesions (e.g. caries versus abrasion). This currently in progress experimental activity represents the first step for the set-up of a research center specifically devoted to the realization of advanced studies in the field of archaeo-paleobiology.

MODIS-derived daily PAR simulation from cloud-free images and its validation

Energy Technology Data Exchange (ETDEWEB)

Chen, Liangfu; Gu, Xingfa; Tian, Guoliang [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); The Center for National Spaceborne Demonstration, Beijing 100101 (China); Gao, Yanhua [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Yang, Lei [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China); Jilin University, Changchun 130026 (China); Liu, Qinhuo [State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101 (China)

2008-06-15

In this paper, a MODIS-derived daily PAR (photosynthetically active radiation) simulation model from cloud-free image over land surface has been developed based on Bird and Riordan's model. In this model, the total downwelling spectral surface irradiance is divided into two parts: one is beam irradiance, and another is diffuse irradiance. The attenuation of solar beam irradiance comprises scattering by the gas mixture, absorption by ozone, the gas mixture and water vapor, and scattering and absorption by aerosols. The diffuse irradiance is scattered out of the direct beam and towards the surface. The multiple ground-air interactions have been taken into account in the diffuse irradiance model. The parameters needed in this model are atmospheric water vapor content, aerosol optical thickness and spectral albedo ranging from 400 nm to 700 nm. They are all retrieved from MODIS data. Then, the instantaneous photosynthetically available radiation (IPAR) is integrated by using a weighted sum at each of the visible MODIS wavebands. Finally, a daily PAR is derived by integration of IPAR. In order to validate the MODIS-derived PAR model, we compared the field PAR measurements in 2003 and 2004 against the simulated PAR. The measurements were made at the Qianyanzhou ecological experimental station, Chinese Ecosystem Research Network. A total of 54 days of cloud-free MODIS L1B level images were used for the PAR simulation. Our results show that the simulated PAR is consistent with field measurements, where the correlation coefficient of linear regression between calculated PAR and measured PAR is 0.93396. However, there were some uncertainties in the comparison of 1 km pixel PAR with the tower flux stand measurement. (author)

PAR-2 expression in the gingival crevicular fluid reflects chronic periodontitis severity.

Science.gov (United States)

Fukushima, Henrique; Alves, Vanessa Tubero Euzebio; Carvalho, Verônica Franco de; Ambrósio, Lucas Macedo Batitucci; Eichler, Rosangela Aparecida Dos Santos; Carvalho, Maria Helena Catelli de; Saraiva, Luciana; Holzhausen, Marinella

2017-01-26

Recent studies investigating protease-activated receptor type 2 (PAR-2) suggest an association between the receptor and periodontal inflammation. It is known that gingipain, a bacterial protease secreted by the important periodontopathogen Porphyromonas gingivalis can activate PAR-2. Previous studies by our group found that PAR-2 is overexpressed in the gingival crevicular fluid (GCF) of patients with moderate chronic periodontitis (MP). The present study aimed at evaluating whether PAR-2 expression is associated with chronic periodontitis severity. GCF samples and clinical parameters, including plaque and bleeding on probing indices, probing pocket depth and clinical attachment level, were collected from the control group (n = 19) at baseline, and from MP patients (n = 19) and severe chronic periodontitis (SP) (n = 19) patients before and 6 weeks after periodontal non-surgical treatment. PAR-2 and gingipain messenger RNA (mRNA) in the GCF of 4 periodontal sites per patient were evaluated by Reverse Transcription Polymerase Chain Reaction (RT-qPCR). PAR-2 and gingipain expressions were greater in periodontitis patients than in control group patients. In addition, the SP group presented increased PAR-2 and gingipain mRNA levels, compared with the MP group. Furthermore, periodontal treatment significantly reduced (p periodontitis. In conclusion, PAR-2 is associated with chronic periodontitis severity and with gingipain levels in the periodontal pocket, thus suggesting that PAR-2 expression in the GCF reflects the severity of destruction during periodontal infection.

In vivo microCT imaging of rodent cerebral vasculature

International Nuclear Information System (INIS)

Seo, Youngho; Hasegawa, Bruce H; Hashimoto, Tomoki; Nuki, Yoshitsugu

2008-01-01

Computed tomography (CT) remains a critical diagnostic tool for evaluating patients with cerebrovascular disease, and the advent of specialized systems for imaging rodents has extended these techniques to small animal models of these diseases. We therefore have evaluated in vivo methods of imaging rat models of hemorrhagic stroke using a high resolution compact computed tomography ('microCT') system (FLEX(tm) X-O(tm), Gamma Medica-Ideas, Northridge, CA). For all in vivo studies, the head of the anesthetized rat was secured in a custom immobilization device for microCT imaging with 512 projections over 2 min at 60 kVp and 0.530 mA (I tube x t/rotation = 63.6 mAs). First, imaging without iodinated contrast was performed (a) to differentiate the effect of contrast agent in contrast-enhanced CT and (b) to examine the effectiveness of the immobilization device between two time points of CT acquisitions. Then, contrast-enhanced CT was performed with continuous administration of iopromide (300 mgI ml -1 at 1.2 ml min -1 ) to visualize aneurysms and other vascular formations in the carotid and cerebral arteries that may precede subarachnoid hemorrhage. The accuracy of registration between the noncontrast and contrast-enhanced CT images with the immobilization device was compared against the images aligned with normalized mutual information using FMRIB's linear image registration tool (FLIRT). Translations and rotations were examined between the FLIRT-aligned noncontrast CT image and the nonaligned noncontrast CT image. These two data sets demonstrated translational and rotational differences of less than 0.5 voxel (∼85 μm) and 0.5 deg., respectively. Noncontrast CT demonstrated a very small volume (0.1 ml) of femoral arterial blood introduced surgically into the rodent brain. Continuous administration of iopromide during the CT acquisition produced consistent vascular contrast in the reconstructed CT images. As a result, carotid arteries and major cerebral blood vessels

In vivo microCT imaging of rodent cerebral vasculature

Energy Technology Data Exchange (ETDEWEB)

Seo, Youngho; Hasegawa, Bruce H [Center for Molecular and Functional Imaging, Department of Radiology, University of California, San Francisco, CA 94143 (United States); Hashimoto, Tomoki; Nuki, Yoshitsugu [Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143 (United States)], E-mail: youngho.seo@radiology.ucsf.edu

2008-04-07

Computed tomography (CT) remains a critical diagnostic tool for evaluating patients with cerebrovascular disease, and the advent of specialized systems for imaging rodents has extended these techniques to small animal models of these diseases. We therefore have evaluated in vivo methods of imaging rat models of hemorrhagic stroke using a high resolution compact computed tomography ('microCT') system (FLEX(tm) X-O(tm), Gamma Medica-Ideas, Northridge, CA). For all in vivo studies, the head of the anesthetized rat was secured in a custom immobilization device for microCT imaging with 512 projections over 2 min at 60 kVp and 0.530 mA (I{sub tube} x t/rotation = 63.6 mAs). First, imaging without iodinated contrast was performed (a) to differentiate the effect of contrast agent in contrast-enhanced CT and (b) to examine the effectiveness of the immobilization device between two time points of CT acquisitions. Then, contrast-enhanced CT was performed with continuous administration of iopromide (300 mgI ml{sup -1} at 1.2 ml min{sup -1}) to visualize aneurysms and other vascular formations in the carotid and cerebral arteries that may precede subarachnoid hemorrhage. The accuracy of registration between the noncontrast and contrast-enhanced CT images with the immobilization device was compared against the images aligned with normalized mutual information using FMRIB's linear image registration tool (FLIRT). Translations and rotations were examined between the FLIRT-aligned noncontrast CT image and the nonaligned noncontrast CT image. These two data sets demonstrated translational and rotational differences of less than 0.5 voxel ({approx}85 {mu}m) and 0.5 deg., respectively. Noncontrast CT demonstrated a very small volume (0.1 ml) of femoral arterial blood introduced surgically into the rodent brain. Continuous administration of iopromide during the CT acquisition produced consistent vascular contrast in the reconstructed CT images. As a result, carotid

Molecular mechanism of bundle formation by the bacterial actin ParM

Energy Technology Data Exchange (ETDEWEB)

Popp, David, E-mail: dpopp@imcb.a-star.edu.sg [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673 Singapore (Singapore); Narita, Akihiro [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Iwasa, Mitsusada [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Maeda, Yuichiro [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Robinson, Robert C. [Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673 Singapore (Singapore)

2010-01-22

The actin homolog ParM plays a microtubule-like role in segregating DNA prior to bacterial cell division. Fluorescence and cryo-electron microscopy have shown that ParM forms filament bundles between separating DNA plasmids in vivo. Given the lack of ParM bundling proteins it remains unknown how ParM bundles form at the molecular level. Here we show using time-lapse TIRF microscopy, under in vitro molecular crowding conditions, that ParM-bundle formation consists of two distinct phases. At the onset of polymerization bundle thickness and shape are determined in the form of nuclei of short helically disordered filaments arranged in a liquid-like lattice. These nuclei then undergo an elongation phase whereby they rapidly increase in length. At steady state, ParM bundles fuse into one single large aggregate. This behavior had been predicted by theory but has not been observed for any other cytomotive biopolymer, including F-actin. We employed electron micrographs of ParM rafts, which are 2-D analogs of 3-D bundles, to identify the main molecular interfilament contacts within these suprastructures. The interface between filaments is similar for both parallel and anti-parallel orientations and the distribution of filament polarity is random within a bundle. We suggest that the interfilament interactions are not due to the interactions of specific residues but rather to long-range, counter ion mediated, electrostatic attractive forces. A randomly oriented bundle ensures that the assembly is rigid and that DNA may be captured with equal efficiency at both ends of the bundle via the ParR binding protein.

Sustainable Micro-Manufacturing of Micro-Components via Micro Electrical Discharge Machining

Directory of Open Access Journals (Sweden)

Valeria Marrocco

2011-12-01

Full Text Available Micro-manufacturing emerged in the last years as a new engineering area with the potential of increasing peoples’ quality of life through the production of innovative micro-devices to be used, for example, in the biomedical, micro-electronics or telecommunication sectors. The possibility to decrease the energy consumption makes the micro-manufacturing extremely appealing in terms of environmental protection. However, despite this common belief that the micro-scale implies a higher sustainability compared to traditional manufacturing processes, recent research shows that some factors can make micro-manufacturing processes not as sustainable as expected. In particular, the use of rare raw materials and the need of higher purity of processes, to preserve product quality and manufacturing equipment, can be a source for additional environmental burden and process costs. Consequently, research is needed to optimize micro-manufacturing processes in order to guarantee the minimum consumption of raw materials, consumables and energy. In this paper, the experimental results obtained by the micro-electrical discharge machining (micro-EDM of micro-channels made on Ni–Cr–Mo steel is reported. The aim of such investigation is to shed a light on the relation and dependence between the material removal process, identified in the evaluation of material removal rate (MRR and tool wear ratio (TWR, and some of the most important technological parameters (i.e., open voltage, discharge current, pulse width and frequency, in order to experimentally quantify the material waste produced and optimize the technological process in order to decrease it.

From the sample preparation to the volume rendering images of small animals: A step by step example of a procedure to carry out the micro-CT study of the leafhopper insect Homalodisca vitripennis (Hemiptera: Cicadellidae)

Science.gov (United States)

Advances in micro-CT, digital computed tomography (CT) scan uses X-rays to make detailed pictures of structures inside of the body. Combining micro-CT with Digital Video Library systems, and linking this to Big Data, will change the way researchers, entomologist, and the public search and use anato...

Algorithmic fundamentals of computerized tomography and of transverse analogue tomography

International Nuclear Information System (INIS)

Heckmann, K.

1981-01-01

Computerized tomography and transverse analogue tomography are two different approaches to the same goal, namely, transverse tomography. The algorithm is discussed and compared. Transverse tomography appears capable of further development, judging by this comparison. (orig.) [de

Par Pond vegetation status Summer 1995 -- October survey descriptive summary

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1995-11-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the emergent shoreline aquatic plant communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level and continued with this late October survey. Communities similar to the pre-drawdown Par Pond aquatic plant communities are becoming re-established; especially, beds of maiden cane, lotus, waterlily, and watershield are now extensive and well established. Cattail occurrence continues to increase, but large beds common to Par Pond prior to the drawdown have not formed. Future surveys throughout 1996 and 1997, along with the continued evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

Par Pond vegetation status Summer 1995 -- September survey descriptive summary

International Nuclear Information System (INIS)

Mackey, H.E. Jr.; Riley, R.S.

1995-09-01

The water level of Par Pond was lowered approximately 20 feet in mid-1991 in order to protect downstream residents from possible dam failure suggested by subsidence on the downstream slope of the dam and to repair the dam. This lowering exposed both emergent and nonemergent macrophyte beds to drying conditions resulting in extensive losses. A survey of the emergent shoreline aquatic plant communities began in June 1995, three months after the refilling of Par Pond to approximately 200 feet above mean sea level and continued with this mid-September survey. Communities similar to the pre-drawdown Par Pond aquatic plant communities are becoming re-established; especially, beds of maidencane, lotus, waterlily, and watershield are now extensive and well established. Cattail occurrence continues to increase, but large beds common to Par Pond prior to the drawdown have not formed. Future surveys during the late growing seasons of 1995, and throughout 1996 and 1997, along with the evaluation of satellite data to map the areal extent of the macrophyte beds of Par Pond, are planned

Improved Satellite-based Photosysnthetically Active Radiation (PAR) for Air Quality Studies

Science.gov (United States)

Pour Biazar, A.; McNider, R. T.; Cohan, D. S.; White, A.; Zhang, R.; Dornblaser, B.; Doty, K.; Wu, Y.; Estes, M. J.

2015-12-01

One of the challenges in understanding the air quality over forested regions has been the uncertainties in estimating the biogenic hydrocarbon emissions. Biogenic volatile organic compounds, BVOCs, play a critical role in atmospheric chemistry, particularly in ozone and particulate matter (PM) formation. In southeastern United States, BVOCs (mostly as isoprene) are the dominant summertime source of reactive hydrocarbon. Despite significant efforts in improving BVOC estimates, the errors in emission inventories remain a concern. Since BVOC emissions are particularly sensitive to the available photosynthetically active radiation (PAR), model errors in PAR result in large errors in emission estimates. Thus, utilization of satellite observations to estimate PAR can help in reducing emission uncertainties. Satellite-based PAR estimates rely on the technique used to derive insolation from satellite visible brightness measurements. In this study we evaluate several insolation products against surface pyranometer observations and offer a bias correction to generate a more accurate PAR product. The improved PAR product is then used in biogenic emission estimates. The improved biogenic emission estimates are compared to the emission inventories over Texas and used in air quality simulation over the period of August-September 2013 (NASA's Discover-AQ field campaign). A series of sensitivity simulations will be performed and evaluated against Discover-AQ observations to test the impact of satellite-derived PAR on air quality simulations.

Gas bubble network formation in irradiated beryllium pebbles monitored by X-Ray micro-tomography

Energy Technology Data Exchange (ETDEWEB)

Bolier, E; Ferrero, C. [Forschungszentrum Karlsruhe, Zimer 203, Gebaeude 451, Abteilung HVT-TL (Germany); Moslang, A. [Forschungszentrum Karlsruhe GmbH, FZK, Karlsruhe (Germany); Pieritz, R.A. [CNRS, Lab. de Glaciologie et Geophysique de l' Environnement, 38 - Saint Martin d' Heres (France)

2007-07-01

Full text of publication follows: The efficient and safe operation of helium cooled ceramic breeder blankets requires among others an efficient tritium release during operation at blanket relevant temperatures. In the past out-of-pile thermal desorption studies on low temperature neutron irradiated beryllium have shown that tritium and helium release peaks occur together. This phenomenon can be interpreted in terms of growth and coalescence of helium bubbles and tritium that either is trapped inside the helium bubbles in form of T{sub 2} molecules or in their strain field. With increasing temperature the bubble density and size at grain interfaces increase together with the probability of interconnected porosities and channel formation to the outer surface, leading to simultaneous helium and tritium release peaks in TDS. For a reliable prediction of gas release up to end-of-life conditions at blanket relevant temperatures, knowledge of the dynamics of bubble growth and coalescence as well as the 3D distribution of bubble network formation is indispensable. Such data could also be used to experimentally validate any future model predictions of tritium and helium release rates. A high resolution computer aided micro-tomography (CMT) setup has been developed at the European Synchrotron Radiation Facility which allowed reconstructing 3-D images of beryllium pebbles without damaging them. By postprocessing the data a 3D rendering of inner surfaces and of interconnected channel networks can be obtained, thus allowing the identification of open porosities in neutron irradiated and tempered beryllium pebbles. In our case Beryllium pebbles of 2 mm diameter had been neutron irradiated in the 'Beryllium' experiment at 770 K with 1.24 x 10{sup 25} nxm{sup -2} resulting in 480 appm He and 12 appm Tritium. After annealing at 1500 K CMT was performed on the pebbles with 4.9 and 1.4 {mu}m voxel resolution, respectively, followed by morphological and topological post

Structure from Motion Photogrammetry and Micro X-Ray Computed Tomography 3-D Reconstruction Data Fusion for Non-Destructive Conservation Documentation of Lunar Samples

Science.gov (United States)

Beaulieu, K. R.; Blumenfeld, E. H.; Liddle, D. A.; Oshel, E. R.; Evans, C. A.; Zeigler, R. A.; Righter, K.; Hanna, R. D.; Ketcham, R. A.

2017-01-01

Our team is developing a modern, cross-disciplinary approach to documentation and preservation of astromaterials, specifically lunar and meteorite samples stored at the Johnson Space Center (JSC) Lunar Sample Laboratory Facility. Apollo Lunar Sample 60639, collected as part of rake sample 60610 during the 3rd Extra-Vehicular Activity of the Apollo 16 mission in 1972, served as the first NASA-preserved lunar sample to be examined by our team in the development of a novel approach to internal and external sample visualization. Apollo Sample 60639 is classified as a breccia with a glass-coated side and pristine mare basalt and anorthosite clasts. The aim was to accurately register a 3-dimensional Micro X-Ray Computed Tomography (XCT)-derived internal composition data set and a Structure-From-Motion (SFM) Photogrammetry-derived high-fidelity, textured external polygonal model of Apollo Sample 60639. The developed process provided the means for accurate, comprehensive, non-destructive visualization of NASA's heritage lunar samples. The data products, to be ultimately served via an end-user web interface, will allow researchers and the public to interact with the unique heritage samples, providing a platform to "slice through" a photo-realistic rendering of a sample to analyze both its external visual and internal composition simultaneously.

Applying a foil queue micro-electrode in micro-EDM to fabricate a 3D micro-structure

Science.gov (United States)

Xu, Bin; Guo, Kang; Wu, Xiao-yu; Lei, Jian-guo; Liang, Xiong; Guo, Deng-ji; Ma, Jiang; Cheng, Rong

2018-05-01

Applying a 3D micro-electrode in a micro electrical discharge machining (micro-EDM) can fabricate a 3D micro-structure with an up and down reciprocating method. However, this processing method has some shortcomings, such as a low success rate and a complex process for fabrication of 3D micro-electrodes. By focusing on these shortcomings, this paper proposed a novel 3D micro-EDM process based on the foil queue micro-electrode. Firstly, a 3D micro-electrode was discretized into several foil micro-electrodes and these foil micro-electrodes constituted a foil queue micro-electrode. Then, based on the planned process path, foil micro-electrodes were applied in micro-EDM sequentially and the micro-EDM results of each foil micro-electrode were able to superimpose the 3D micro-structure. However, the step effect will occur on the 3D micro-structure surface, which has an adverse effect on the 3D micro-structure. To tackle this problem, this paper proposes to reduce this adverse effect by rounded corner wear at the end of the foil micro-electrode and studies the impact of machining parameters on rounded corner wear and the step effect on the micro-structure surface. Finally, using a wire cutting voltage of 80 V, a current of 0.5 A and a pulse width modulation ratio of 1:4, the foil queue micro-electrode was fabricated by wire electrical discharge machining. Also, using a pulse width of 100 ns, a pulse interval of 200 ns, a voltage of 100 V and workpiece material of 304# stainless steel, the foil queue micro-electrode was applied in micro-EDM for processing of a 3D micro-structure with hemispherical features, which verified the feasibility of this process.