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https://www.readbyqxmd.com/read/28081365/visualizing-arsenate-reactions-and-encapsulation-in-a-single-zero-valent-iron-nanoparticle
#1
Lan Ling, Wei-Xian Zhang
A nanostructure-based mechanism is presented on the enrichment, separation and immobilization of arsenic with nanoscale Zero-Valent Iron (nZVI). The As-Fe reactions are studied with Spherical Aberration Corrected Scanning Transmission Electron Microscopy (Cs-STEM). Near atomic-resolution (<1 nm3) electron tomography discovers a thin continuous layer (23±3 Å) of elemental arsenic sandwiched between the iron oxide shell and the zero-valent iron core. This points to a unique mechanism of nano-encapsulation and proves that the outer layer, especially the Fe(0)/oxide interface is the edge of the As-Fe reactions...
January 12, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28081000/on-the-development-of-a-vipar-nd-radiotherapy-3d-polymer-gel-dosimeter
#2
Marek Kozicki, Malwina Jaszczak, Piotr Maras, Mariusz Dudek, Marian Cłapa
This work presents an improvement of the VIPAR(nd) ('nd' stands for 'normoxic, double', or VIP) polymer gel dosimeter. The gel composition was altered by increasing the concentration of the monomeric components, N-vinylpyrrolidone (NVP) and N,N'-methylenebisacrylamide (MBA), in co-solvent solutions. The optimal composition (VIPAR(CT), where 'CT' stands for computed tomography, or VIC) comprised: 17% NVP, 8% MBA, 12% t-BuOH, 7.5% gelatine, 0.007% ascorbic acid, 0.0008% CuSO4  ×  5H2O and 0.02% hydroquinone...
January 12, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28076372/bad-to-the-bone-on-in-vitro-and-ex-vivo-microbial-biofilm-ability-to-directly-destroy-colonized-bone-surfaces-without-participation-of-host-immunity-or-osteoclastogenesis
#3
Adam Junka, Patrycja Szymczyk, Grzegorz Ziółkowski, Ewa Karuga-Kuzniewska, Danuta Smutnicka, Iwona Bil-Lula, Marzenna Bartoszewicz, Susan Mahabady, Parish Paymon Sedghizadeh
Bone infections are a significant public health burden associated with morbidity and mortality in patients. Microbial biofilm pathogens are the causative agents in chronic osteomyelitis. Research on the pathogenesis of osteomyelitis has focused on indirect bone destruction by host immune cells and cytokines secondary to microbial insult. Direct bone resorption by biofilm pathogens has not yet been seriously considered. In this study, common osteomyelitis pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Streptococcus mutans) were grown as biofilms in multiple in vitro and ex vivo experiments to analyze quantitative and qualitative aspects of bone destruction during infection...
2017: PloS One
https://www.readbyqxmd.com/read/28076338/quantification-of-confounding-factors-in-mri-based-dose-calculations-as-applied-to-prostate-imrt
#4
Matteo Maspero, Peter R Seevinck, Gerald Schubert, Michaela A U Hoesl, Bram van Asselen, Max A Viergever, Jan J W Lagendijk, Gert J Meijer, Cornelis A T van den Berg
Magnetic resonance (MR)-only radiotherapy treatment planning requires pseudo-CT (pCT) images to enable MR-based dose calculations. To verify the accuracy of MR-based dose calculations, institutions interested in introducing MR-only planning will have to compare pCT-based and computer tomography (CT)-based dose calculations. However, interpreting such comparison studies may be challenging, since potential differences arise from a range of confounding factors which are not necessarily specific to MR-only planning...
January 11, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28074015/electron-absorbed-fractions-in-an-image-based-microscopic-skeletal-dosimetry-model-of-chinese-adult-male
#5
Shenshen Gao, Li Ren, Rui Qiu, Zhen Wu, Chunyan Li, Junli Li
Based on the Chinese reference adult male voxel model, a set of microscopic skeletal models of Chinese adult male is constructed through the processes of computed tomography (CT) imaging, bone coring, micro-CT imaging, image segmentation, merging into macroscopic bone model and implementation in Geant4. At the step of image segmentation, a new bone endosteum (BE) segmentation method is realized by sampling. The set of model contains 32 spongiosa samples with voxel size of 19 μm cubes. The microscopic spongiosa bone data for Chinese adult male are provided...
January 10, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28070917/dual-energy-ct-quantitative-imaging-a-comparison-study-between-twin-beam-and-dual-source-ct-scanners
#6
Isabel P Almeida, Lotte E J R Schyns, Michel C Öllers, Wouter van Elmpt, Katia Parodi, Guillaume Landry, Frank Verhaegen
PURPOSE: To assess image quality and to quantify the accuracy of relative electron densities (ρe ) and effective atomic numbers (Zeff ) for three dual-energy computed tomography (DECT) scanners: a novel single-source split-filter (i.e., twin-beam) and two dual-source scanners. METHODS: Measurements were made with a second generation dual-source scanner at 80/140Sn kVp, a third-generation twin-beam single-source scanner at 120 kVp with gold (Au) and tin (Sn) filters, and a third-generation dual-source scanner at 90/150Sn kVp...
November 19, 2016: Medical Physics
https://www.readbyqxmd.com/read/28068232/analysis-of-the-factors-contributing-to-vertebral-compression-fractures-after-spine-stereotactic-radiosurgery
#7
David Boyce-Fappiano, Erinma Elibe, Lonni Schultz, Samuel Ryu, M Salim Siddiqui, Indrin Chetty, Ian Lee, Jack Rock, Benjamin Movsas, Farzan Siddiqui
PURPOSE: To determine our institutional vertebral compression fracture (VCF) rate after spine stereotactic radiosurgery (SRS) and determine contributory factors. METHODS AND MATERIALS: Retrospective analysis from 2001 to 2013 at a single institution was performed. With institutional review board approval, electronic medical records of 1905 vertebral bodies from 791 patients who were treated with SRS for the management of primary or metastatic spinal lesions were reviewed...
February 1, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28065307/analysis-of-cytokinesis-by-electron-microscopy
#8
J König, J Borrego-Pinto, D Streichert, M Munzig, P Lenart, T Müller-Reichert
Following up on a chapter on the Correlative Light and Electron Microscopy of Early Caenorhabditis elegans Embryos in Mitosis (MCB 79, 101-119), we present an adaptation of our established protocol for the ultrastructural analysis of either permeabilized or injected embryonic systems. We prepared both drug-treated early C. elegans embryos and fluorescently labeled sea urchin embryos of Lytechinus pictus for ultrastructural studies on animal cytokinesis. Here we focus on the initial preparation steps of postmitotic embryos for high-pressure freezing and subsequent electron microscopy with an emphasis on electron tomography...
2017: Methods in Cell Biology
https://www.readbyqxmd.com/read/28064041/recovering-fine-details-from-under-resolved-electron-tomography-data-using-higher-order-total-variation-%C3%A2-1-regularization
#9
Toby Sanders, Anne Gelb, Rodrigo B Platte, Ilke Arslan, Kai Landskron
Over the last decade or so, reconstruction methods using ℓ1 regularization, often categorized as compressed sensing (CS) algorithms, have significantly improved the capabilities of high fidelity imaging in electron tomography. The most popular ℓ1 regularization approach within electron tomography has been total variation (TV) regularization. In addition to reducing unwanted noise, TV regularization encourages a piecewise constant solution with sparse boundary regions. In this paper we propose an alternative ℓ1 regularization approach for electron tomography based on higher order total variation (HOTV)...
January 3, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28063337/laser-assisted-atom-probe-tomography-of-ti-tin-films-deposited-on-si
#10
N A Sanford, P T Blanchard, R White, M R Vissers, D R Diercks, A V Davydov, D P Pappas
Laser-assisted atom probe tomography (L-APT) was used to examine superconducting TiN/Ti/TiN trilayer films with nominal respective thicknesses of 5/5/5 (nm). Such materials are of interest for applications that require large arrays of microwave kinetic inductance detectors. The trilayers were deposited on Si substrates by reactive sputtering. Electron energy loss microscopy performed in a scanning transmission electron microscope (STEM/EELS) was used to corroborate the L-APT results and establish the overall thicknesses of the trilayers...
December 21, 2016: Micron: the International Research and Review Journal for Microscopy
https://www.readbyqxmd.com/read/28060414/standardizing-ct-lung-density-measure-across-scanner-manufacturers
#11
Huaiyu Heather Chen-Mayer, Matthew K Fuld, Bernice Hoppel, Philip F Judy, Jered P Sieren, Junfeng Guo, David A Lynch, Antonio Possolo, Sean B Fain
PURPOSE: Computed Tomography (CT) imaging of the lung, reported in Hounsfield Units (HU), can be parameterized as a quantitative image biomarker for the diagnosis and monitoring of lung density changes due to emphysema, a type of chronic obstructive pulmonary disease (COPD). CT lung density metrics are global measurements based on lung CT number histograms, and are typically a quantity specifying either the percentage of voxels with CT numbers below a threshold, or a single CT number below which a fixed relative lung volume, nth percentile, falls...
January 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/28060071/corneal-lenticule-allotransplantation-after-femtosecond-laser-small-incision-lenticule-extraction-in-rabbits
#12
Jing Zhao, Yang Shen, Mi Tian, Ling Sun, Yu Zhao, Xiaoyu Zhang, Xingtao Zhou
PURPOSE: To investigate the feasibility of allotransplanting extracted lenticules after femtosecond laser-assisted small incision lenticule extraction (SMILE) in rabbits and the subsequent healing process. METHODS: Fourteen New Zealand white rabbits were divided evenly into 2 groups. The rabbits in group A received SMILE procedures with a -6.00 D correction. The lenticules from group A were immediately inserted into a femtosecond laser-created corneal stromal pocket in group B...
February 2017: Cornea
https://www.readbyqxmd.com/read/28058411/spontaneous-formation-of-nanometer-scale-tubular-vesicles-in-aqueous-mixtures-of-lipid-and-block-copolymer-amphiphiles
#13
Seng Koon Lim, Andrew S W Wong, Hans-Peter M de Hoog, Padmini Rangamani, Atul N Parikh, Madhavan Nallani, Sara Sandin, Bo Liedberg
Many common amphiphiles self-assemble in water to produce heterogeneous populations of discrete and symmetric but polydisperse and multilamellar vesicles isolating the encapsulated aqueous core from the surrounding bulk. But when mixtures of amphiphiles of vastly different elastic properties co-assemble, their non-uniform molecular organization can stabilize lower symmetries and produce novel shapes. Here, using high resolution electron cryomicroscopy and tomography, we identify the spontaneous formation of a membrane morphology consisting of unilamellar tubular vesicles in dilute aqueous solutions of binary mixtures of two different amphiphiles of vastly different origins...
January 6, 2017: Soft Matter
https://www.readbyqxmd.com/read/28058284/why-do-membranes-of-some-unhealthy-cells-adopt-a-cubic-architecture
#14
Qi Xiao, Zhichun Wang, Dewight Williams, Pawaret Leowanawat, Mihai Peterca, Samuel E Sherman, Shaodong Zhang, Daniel A Hammer, Paul A Heiney, Steven R King, David M Markovitz, Sabine André, Hans-Joachim Gabius, Michael L Klein, Virgil Percec
Nonlamellar lipid arrangements, including cubosomes, appear in unhealthy cells, e.g., when they are subject to stress, starvation, or viral infection. The bioactivity of cubosomes-nanoscale particles exhibiting bicontinuous cubic structures-versus more common vesicles is an unexplored area due to lack of suitable model systems. Here, glycodendrimercubosomes (GDCs)-sugar-presenting cubosomes assembled from Janus glycodendrimers by simple injection into buffer-are proposed as mimics of biological cubic membranes...
December 28, 2016: ACS Central Science
https://www.readbyqxmd.com/read/28054636/atomic-scale-chemical-tomography-of-human-bone
#15
Brian Langelier, Xiaoyue Wang, Kathryn Grandfield
Human bone is a complex hierarchical material. Understanding bone structure and its corresponding composition at the nanometer scale is critical for elucidating mechanisms of biomineralization under healthy and pathological states. However, the three-dimensional structure and chemical nature of bone remains largely unexplored at the nanometer scale due to the challenges associated with characterizing both the structural and chemical integrity of bone simultaneously. Here, we use correlative transmission electron microscopy and atom probe tomography for the first time, to our knowledge, to reveal structures in human bone at the atomic level...
January 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28054154/interstitial-cell-modulation-of-pyeloureteric-peristalsis-in-the-mouse-renal-pelvis-examined-using-fibsem-tomography-and-calcium-indicators
#16
Hikaru Hashitani, Michael J Nguyen, Haruka Noda, Retsu Mitsui, Ryuhei Higashi, Keisuke Ohta, Kei-Ichiro Nakamura, Richard J Lang
Typical and atypical smooth muscle cells (TSMCs and ASMCs, respectively) and interstitial cells (ICs) within the pacemaker region of the mouse renal pelvis were examined using focused ion beam scanning electron (FIB SEM) tomography, immunohistochemistry and Ca(2+) imaging. Individual cells within 500-900 electron micrograph stacks were volume rendered and associations with their neighbours established. 'Ribbon-shaped', Ano1 Cl(-) channel immuno-reactive ICs were present in the adventitia and the sub-urothelial space adjacent to the TSMC layer...
January 4, 2017: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/28053229/atg9-regulates-autophagosome-progression-from-the-endoplasmic-reticulum-in-arabidopsis
#17
Xiaohong Zhuang, Kin Pan Chung, Yong Cui, Weili Lin, Caiji Gao, Byung-Ho Kang, Liwen Jiang
Autophagy is a conserved pathway for bulk degradation of cytoplasmic material by a double-membrane structure named the autophagosome. The initiation of autophagosome formation requires the recruitment of autophagy-related protein 9 (ATG9) vesicles to the preautophagosomal structure. However, the functional relationship between ATG9 vesicles and the phagophore is controversial in different systems, and the molecular function of ATG9 remains unknown in plants. Here, we demonstrate that ATG9 is essential for endoplasmic reticulum (ER)-derived autophagosome formation in plants...
January 4, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28052246/synucleins-have-multiple-effects-on-presynaptic-architecture
#18
Karina J Vargas, Nikolas Schrod, Taylor Davis, Ruben Fernandez-Busnadiego, Yumiko V Taguchi, Ulrike Laugks, Vladan Lucic, Sreeganga S Chandra
Synucleins (α, β, γ-synuclein) are a family of abundant presynaptic proteins. α-Synuclein is causally linked to the pathogenesis of Parkinson's disease (PD). In an effort to define their physiological and pathological function or functions, we investigated the effects of deleting synucleins and overexpressing α-synuclein PD mutations, in mice, on synapse architecture using electron microscopy (EM) and cryoelectron tomography (cryo-ET). We show that synucleins are regulators of presynapse size and synaptic vesicle (SV) pool organization...
January 3, 2017: Cell Reports
https://www.readbyqxmd.com/read/28048800/su-f-t-112-long-term-follow-up-of-nsclc-patients-treated-with-lung-sbrt-using-the-modified-conformal-arc-mdca-planning-technique
#19
E Ku, A Desai, D Fang, C Lawrence, C Iannuzzi, C Shi
PURPOSE: To assess long-term toxicity and primary tumor changes for Stage I/II non-small cell lung carcinoma (NSCLC) patients after treatment with lung SBRT using the modified dynamic conformal arc (MDCA) planning technique. METHODS: Clinical and radiograph data from electronic health records of 15 NSCLC patients treated with lung SBRT utilizing the MDCA technique between October 2011 and July 2014 were retrospectively reviewed. MDCA uses a coplanar beam arrangement, patient body center for the beam isocenter, and six partial rotation conformal arcs to target the tumor...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048343/th-cd-207b-01-best-in-physics-imaging-development-of-high-brightness-multiple-pixel-x-ray-source-using-oxide-coated-cathodes
#20
P Kandlakunta, R Pham, T Zhang
PURPOSE: To develop and characterize a high brightness multiple-pixel thermionic emission x-ray (MPTEX) source. METHODS: Multiple-pixel x-ray sources allow for designs of novel x-ray imaging techniques, such as fixed gantry CT, digital tomosynthesis, tetrahedron beam computed tomography, etc. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide coated cathodes. Oxide cathode is chosen as the electron source due to its high emission current density and low operating temperature...
June 2016: Medical Physics
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