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Electron tomography

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https://www.readbyqxmd.com/read/29455293/variations-of-transverse-foramina-in-cervical-vertebrae-what-happens-to-the-vertebral-artery
#1
Aristeidis Zibis, Vasileios Mitrousias, Nikolaos Galanakis, Nikoletta Chalampalaki, Dimitrios Arvanitis, Apostolos Karantanas
PURPOSE: The purpose of this study is to examine variations of the foramen transversarium and the vertebral artery in computed tomography angiographies (CTa) of the cervical spine, investigate their coexistence, and present possible considerations regarding such variations in spine surgical procedures. METHODS: Fifty CTa of the neck were retrospectively reviewed. Transverse and anteroposterior diameter of the foramen and diameter of the vertebral artery were measured...
February 17, 2018: European Spine Journal
https://www.readbyqxmd.com/read/29454930/expanding-horizons-of-cryo-tomography-to-larger-volumes
#2
REVIEW
Michael Elbaum
The three dimensional ultrastructure of cells and tissues comes to light with tomography. There is an inherent tension between representing molecular detail at the highest possible resolution, on one hand, and visualizing spatial relations between large organelles or even neighboring cells in large volumes, on the other. Together with its advantages for pristine sample preservation, cryo-tomography brings particular constraints. A major challenge has been the restriction to specimens thinner than the typical cell...
February 15, 2018: Current Opinion in Microbiology
https://www.readbyqxmd.com/read/29453780/bone-conditioned-medium-modulates-the-osteoconductive-properties-of-collagen-membranes-in-a-rat-calvaria-defect-model
#3
Ulrike Kuchler, Tina Rybaczek, Toni Dobask, Patrick Heimel, Stefan Tangl, Jessica Klehm, Matthias Menzel, Reinhard Gruber
OBJECTIVES: Collagen membranes are not limited to be occlusive barriers as they actively support bone regeneration. However, the impact of bone-derived growth factors on their osteoconductive competence has not been examined. METHODS: Twenty adult Sprague Dawley rats were included in the study. Calvaria defects with a diameter of five millimeter were created. The defect was covered with one layer of a collagen membrane previously soaked in conditioned medium of porcine bone chips or in culture medium alone...
February 16, 2018: Clinical Oral Implants Research
https://www.readbyqxmd.com/read/29452869/three-dimensional-printer-aided-casting-of-soft-custom-silicone-boluses-scsbs-for-head-and-neck-radiation-therapy
#4
Tsuicheng Chiu, Jun Tan, Mathew Brenner, Xuejun Gu, Ming Yang, Kenneth Westover, Tobin Strom, David Sher, Steve Jiang, Bo Zhao
PURPOSE: Custom tissue compensators provide dosimetric advantages for treating superficial or complex anatomy, but currently available fabrication technology is expensive or impractical for most clinical operations and yields compensators that are difficult for patients to tolerate. We aimed to develop an inexpensive, clinically feasible workflow for generating patient-specific, soft, custom silicone boluses (SCSBs) for head-and-neck (HN) radiation therapy. METHODS AND MATERIALS: We developed a method using 3-dimensional printed parts for generating SCSBs for the treatment of HN cancers...
November 11, 2017: Practical Radiation Oncology
https://www.readbyqxmd.com/read/29451728/phosphinic-acid-based-linkers-new-building-block-in-mof-chemistry
#5
Jan Hynek, Petr Brázda, Jan Rohlíček, Michael G S Londesborough, Jan Demel
Metal-organic frameworks (MOFs) are a chemically and topologically diverse family of materials composed of inorganic nodes and organic linkers bound together by coordination bonds. In this contribution we present two significant innovations in this field. The first is the use of a new coordination group in phenylene-1,4-bis(methylphosphinic acid) (PBPA), a phosphinic acid analogue of commonly-used terephtalic acid. We show that the use of this new linker group leads to the formation of a hydrothermally stable permanently porous MOF structure...
February 16, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29444030/tomography-of-asymmetric-molecular-orbitals-with-a-one-color-inhomogeneous-field
#6
Hua Yuan, Lixin He, Feng Wang, Baoning Wang, Xiaosong Zhu, Pengfei Lan, Peixiang Lu
We demonstrate image asymmetric molecular orbitals via high-order harmonic generation in a one-color inhomogeneous field. Due to the broken inversion symmetry of the inhomogeneous field in space, the returning electrons with energy in a broad range can be forced to recollide from only one direction for all the orientation angles of molecules, which therefore can be used to reconstruct asymmetric molecular orbitals. Following the procedure of molecular orbital tomography, the highest occupied molecular orbital of carbon monoxide (CO) is satisfactorily reconstructed with high-order harmonic spectra driven by the inhomogeneous field...
February 15, 2018: Optics Letters
https://www.readbyqxmd.com/read/29443772/primary-leiomyosarcoma-in-the-colon-a-case-report
#7
Jing Yang
RATIONALE: Leiomyosarcoma (LMS) is a common type of soft tissue sarcoma. Primary colonic LMS in general is a very rare entity, accounting for 1% to 2% of gastrointestinal malignancies. PATIENT CONCERNS: We report a case of 55-year-old female who presented with a sudden onset of sharp right lower quadrant abdominal pain. Electronic colonoscopy showed a normal lumen. However, an abdominal computed tomography scan revealed a mass of soft tissue attenuation inseparable from the ascending colon which appeared as a gastrointestinal stromal tumor (GIST)...
February 2018: Medicine (Baltimore)
https://www.readbyqxmd.com/read/29442865/complementary-characterization-of-cu-in-ga-se%C3%A2-thin-film-photovoltaic-cells-using-secondary-ion-mass-spectrometry-auger-electron-spectroscopy-and-atom-probe-tomography
#8
Yun Jung Jang, Jihye Lee, Jeung-Hyun Jeong, Kang-Bong Lee, Donghwan Kim, Yeonhee Lee
To enhance the conversion performance of solar cells, a quantitative and depth-resolved elemental analysis of photovoltaic thin films is required. In this study, we determined the average concentration of the major elements (Cu, In, Ga, and Se) in fabricated Cu(In,Ga)Se2 (CIGS) thin films, using inductively coupled plasma atomic emission spectroscopy, X-ray fluorescence, and wavelengthdispersive electron probe microanalysis. Depth profiling results for CIGS thin films with different cell efficiencies were obtained using secondary ion mass spectrometry and Auger electron spectroscopy to compare the atomic concentrations...
May 1, 2018: Journal of Nanoscience and Nanotechnology
https://www.readbyqxmd.com/read/29441085/three-dimensional-architecture-and-biogenesis-of-membrane-structures-associated-with-plant-virus-replication
#9
REVIEW
Xuejiao Jin, Xiuling Cao, Xueting Wang, Jun Jiang, Juan Wan, Jean-François Laliberté, Yongliang Zhang
Positive-sense (+) RNA viruses represent the most abundant group of viruses and are dependent on the host cell machinery to replicate. One remarkable feature that occurs after (+) RNA virus entry into cells is the remodeling of host endomembranes, leading to the formation of viral replication factories. Recently, rapid progress in three-dimensional (3D) imaging technologies, such as electron tomography (ET) and focused ion beam-scanning electron microscopy (FIB-SEM), has enabled researchers to visualize the novel membrane structures induced by viruses at high resolution...
2018: Frontiers in Plant Science
https://www.readbyqxmd.com/read/29433862/three-dimensionally-printed-bioactive-ceramic-scaffold-osseoconduction-across-critical-sized-mandibular-defects
#10
Christopher D Lopez, J Rodrigo Diaz-Siso, Lukasz Witek, Jonathan M Bekisz, Bruce N Cronstein, Andrea Torroni, Roberto L Flores, Eduardo D Rodriguez, Paulo G Coelho
BACKGROUND: Vascularized bone tissue transfer, commonly used to reconstruct large mandibular defects, is challenged by long operative times, extended hospital stay, donor-site morbidity, and resulting health care. 3D-printed osseoconductive tissue-engineered scaffolds may provide an alternative solution for reconstruction of significant mandibular defects. This pilot study presents a novel 3D-printed bioactive ceramic scaffold with osseoconductive properties to treat segmental mandibular defects in a rabbit model...
March 2018: Journal of Surgical Research
https://www.readbyqxmd.com/read/29433078/biofilms-in-3d-porous-media-delineating-the-influence-of-the-pore-network-geometry-flow-and-mass-transfer-on-biofilm-development
#11
Maxence Carrel, Verónica L Morales, Mario A Beltran, Nicolas Derlon, Rolf Kaufmann, Eberhard Morgenroth, Markus Holzner
This study investigates the functional correspondence between porescale hydrodynamics, mass transfer, pore structure and biofilm morphology during progressive biofilm colonization of a porous medium. Hydrodynamics and the structure of both the porous medium and the biofilm are experimentally measured with 3D particle tracking velocimetry and micro X-ray Computed Tomography, respectively. The analysis focuses on data obtained in a clean porous medium after 36 h of biofilm growth. Registration of the particle tracking and X-ray data sets allows to delineate the interplay between porous medium geometry, hydrodynamic and mass transfer processes on the morphology of the developing biofilm...
February 5, 2018: Water Research
https://www.readbyqxmd.com/read/29431911/the-years-algorithm-for-suspected-pulmonary-embolism-shorter-visit-time-and-reduced-costs-at-the-emergency-department
#12
L M van der Pol, C E A Dronkers, T van der Hulle, P L den Exter, C Tromeur, C Heringhaus, A T A Mairuhu, M V Huisman, W B van den Hout, F A Klok
BACKGROUND: Recently, the safety of the YEARS algorithm, designed to simplify the diagnostic work-up of pulmonary embolism (PE), was demonstrated. We hypothesize that by design, YEARS would be associated with a shorter diagnostic emergency department (ED) visit time due to simultaneous assessment of pre-test probability and D-dimer level and reduction in CT-scans. AIM: To investigate whether implementation of the YEARS diagnostic algorithm is associated with a shorter ED visit time compared to the conventional algorithm and to evaluate the associated cost savings...
February 12, 2018: Journal of Thrombosis and Haemostasis: JTH
https://www.readbyqxmd.com/read/29430673/microtubule-inner-proteins-a-meshwork-of-luminal-proteins-stabilizing-the-doublet-microtubule
#13
REVIEW
Muneyoshi Ichikawa, Khanh Huy Bui
Motile eukaryotic cilia and flagella are hair-like organelles responsible for cell motility and mucociliary clearance. Using cryo-electron tomography, it has been shown that the doublet microtubule, the cytoskeleton core of the cilia and flagella, has microtubule inner protein structures binding periodically inside its lumen. More recently, single-particle cryo-electron microscopy analyses of isolated doublet microtubules have shown that microtubule inner proteins form a meshwork inside the doublet microtubule...
February 12, 2018: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
https://www.readbyqxmd.com/read/29429093/visualizing-chemoreceptor-arrays-in-bacterial-minicells-by-cryo-electron-tomography-and-subtomogram-analysis
#14
Zhuan Qin, Bo Hu, Jun Liu
Bacterial chemoreceptors form a highly ordered array in concert with the CheA kinase and the CheW coupling protein. The precise architecture of the array is responsible for high sensitivity, high dynamic range, and strong amplification of chemotaxis signaling. Cryo-electron tomography (cryo-ET) has emerged as a unique tool to visualize bacterial chemotaxis arrays at molecular level. Here we describe a detailed cryo-ET and subtomogram averaging procedure to determine in situ structure of the chemoreceptor arrays in Salmonella minicells...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29428569/a-continuum-of-mineralization-from-human-renal-pyramid-to-stones-on-stems
#15
Benjamin A Sherer, Ling Chen, Misun Kang, Alex R Shimotake, Scott V Wiener, Tom Chi, Marshall L Stoller, Sunita P Ho
The development of new modalities for kidney stone prevention rests upon understanding the progression of mineralization within the renal pyramid. The progression from small foci of mineralization within the renal pyramid to larger interstitial plaques that ultimately lead to the formation of clinically detectable calcium-based stones on calcium phosphate stems will be presented through correlative microscopy approach. High resolution X-ray computed tomography (micro-XCT), electron microscopy, and energy dispersive X-ray (EDX) compositional analyses of interstitial plaques, stems, and attached stones were performed...
February 8, 2018: Acta Biomaterialia
https://www.readbyqxmd.com/read/29426884/a-lumenal-interrupted-helix-in-human-sperm-tail-microtubules
#16
Davide Zabeo, John M Heumann, Cindi L Schwartz, Azusa Suzuki-Shinjo, Garry Morgan, Per O Widlund, Johanna L Höög
Eukaryotic flagella are complex cellular extensions involved in many human diseases gathered under the term ciliopathies. Currently, detailed insights on flagellar structure come mostly from studies on protists. Here, cryo-electron tomography (cryo-ET) was performed on intact human spermatozoon tails and showed a variable number of microtubules in the singlet region (inside the end-piece). Inside the microtubule plus end, a novel left-handed interrupted helix which extends several micrometers was discovered...
February 9, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29426880/three-dimensional-structural-dynamics-of-dna-origami-bennett-linkages-using-individual-particle-electron-tomography
#17
Dongsheng Lei, Alexander E Marras, Jianfang Liu, Chao-Min Huang, Lifeng Zhou, Carlos E Castro, Hai-Jun Su, Gang Ren
Scaffolded DNA origami has proven to be a powerful and efficient technique to fabricate functional nanomachines by programming the folding of a single-stranded DNA template strand into three-dimensional (3D) nanostructures, designed to be precisely motion-controlled. Although two-dimensional (2D) imaging of DNA nanomachines using transmission electron microscopy and atomic force microscopy suggested these nanomachines are dynamic in 3D, geometric analysis based on 2D imaging was insufficient to uncover the exact motion in 3D...
February 9, 2018: Nature Communications
https://www.readbyqxmd.com/read/29425718/effect-of-strontium-surface-functionalized-implants-on-early-and-late-osseointegration-a-histological-spectrometric-and-tomographic-evaluation
#18
Vincent Offermanns, Ole Z Andersen, Gregor Riede, Michael Sillassen, Christian S Jeppesen, Klaus P Almtoft, Heribert Talasz, Caroline Öhman-Magi, Bernd Lethaus, Rene Tolba, Frank Kloss, Morten Foss
Numerous in vivo, in vitro and clinical studies report on beneficial effects of strontium with respect to increased bone growth. Based on this knowledge the aim of this study was to evaluate early and late osseointegration stages of functionalized titanium implants showing sustained release of strontium (Sr) and further investigate its potential systemic effect. Strontium functionalized (Ti-Sr-O) and Grade 4 (Control) titanium implants were inserted in the femoral condyle of New Zealand White rabbits. The Ti-Sr-O coating was characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDX) for structure, coating thickness and chemical composition...
February 6, 2018: Acta Biomaterialia
https://www.readbyqxmd.com/read/29425492/chromosome-translocation-inflates-bacillus-forespores-and-impacts-cellular-morphology
#19
Javier Lopez-Garrido, Nikola Ojkic, Kanika Khanna, Felix R Wagner, Elizabeth Villa, Robert G Endres, Kit Pogliano
The means by which the physicochemical properties of different cellular components together determine bacterial cell shape remain poorly understood. Here, we investigate a programmed cell-shape change during Bacillus subtilis sporulation, when a rod-shaped vegetative cell is transformed to an ovoid spore. Asymmetric cell division generates a bigger mother cell and a smaller, hemispherical forespore. The septum traps the forespore chromosome, which is translocated to the forespore by SpoIIIE. Simultaneously, forespore size increases as it is reshaped into an ovoid...
February 8, 2018: Cell
https://www.readbyqxmd.com/read/29421060/alginate-polymethacrylate-hybrid-hydrogels-for-potential-osteochondral-tissue-regeneration
#20
P Stagnaro, I Schizzi, R Utzeri, E Marsano, M Castellano
Porous scaffolds based on alginate-polymethacrylate hybrid hydrogels intended for bone and cartilage regeneration were prepared through controlled calcium ions diffusion from an agar mould. The double interconnected network of such materials combines into a single porous structure maintained by both noncovalent crosslinks (calcium ions for alginate) and covalent crosslinks (polymethacrylate crosslinked by the addition of mixtures of mono and bifunctional monomers). The alginate component ensures the appropriate micro-environment to mimic the extra-cellular matrix, whereas the polymethacrylate improves the mechanical performances of the hybrid hydrogels, helping to overcome the mechanical limitations of the alginate component...
April 1, 2018: Carbohydrate Polymers
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