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https://www.readbyqxmd.com/read/28231001/crystal-phases-in-hybrid-metal-semiconductor-nanowire-devices
#1
Jeremy David, Francesco Rossella, Mirko Rocci, Daniele Ercolani, Lucia Sorba, Fabio Beltram, Mauro Gemmi, Stefano Roddaro
We investigate the metallic phases observed in hybrid metal-GaAs nanowire devices obtained by controlled thermal annealing of Ni/Au electrodes. Devices are fabricated onto a SiN membrane compatible with transmission electron microscopy studies. Energy dispersive X-ray spectroscopy allows us to show that the nanowire body includes two Ni-rich phases that, thanks to an innovative use of electron diffraction tomography, can be unambiguously identified as Ni3GaAs and Ni5As2 crystals. The mechanisms of Ni incorporation leading to the observed phenomenology are discussed...
February 23, 2017: Nano Letters
https://www.readbyqxmd.com/read/28227855/simultaneous-reconstruction-and-segmentation-with-the-mumford-shah-functional-for-electron-tomography
#2
Li Shen, Eric Todd Quinto, Shiqiang Wang, Ming Jiang, Li Shen, Eric Todd Quinto, Shiqiang Wang, Ming Jiang, Ming Jiang, Eric Todd Quinto, Shiqiang Wang, Li Shen
Electron micrography (EM) is an important method for determining the three-dimensional (3D) structure of macromolecular complexes and biological specimens. But there are several limitations such as poor signal-to-noise, limitation on range of tilt angles and sub-region subject to electron exposure, unintentional movements of the specimen, with EM systems that make the reconstruction procedure a severely ill-posed problem. A different choice of reconstruction method may lead to different results and create different additional artifacts in reconstructed images...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225738/pneumatosis-intestinalis-predictive-evaluation-study-a-multicenter-epidemiologic-study-of-the-american-association-for-the-surgery-of-trauma
#3
Paula Ferrada, Rachael Callcut, Graciela Bauza, Karen R O'Bosky, Xian Luo-Owen, Nicky J Mansfield, Kenji Inaba, Jason Pasley, Nikolay Bugaev, Bruno Pereira, Forrest O Moore, Jinfeng Han, Amelia Pasley, Joseph DuBose
BACKGROUND: Our group has previously published a retrospective review defining variables predictive of transmural bowel ischemia in the setting of pneumatosis intestinalis (PI). We hypothesize this prospective study will confirm the findings of the retrospective review, enhancing legitimacy to the predictive factors for pathologic PI previously highlighted. METHODS: Data were collected using the Research Electronic Data Capture. Forward logistic regression was utilized to identify independent predictors for pathologic PI...
March 2017: Journal of Trauma and Acute Care Surgery
https://www.readbyqxmd.com/read/28222906/microstructural-characterization-of-dental-zinc-phosphate-cements-using-combined-small-angle-neutron-scattering-and-microfocus-x-ray-computed-tomography
#4
Alberto Viani, Konstantinos Sotiriadis, Ivana Kumpová, Lucia Mancini, Marie-Sousai Appavou
OBJECTIVE: To characterize the microstructure of two zinc phosphate cement formulations in order to investigate the role of liquid/solid ratio and composition of powder component, on the developed porosity and, consequently, on compressive strength. METHODS: X-ray powder diffraction with the Rietveld method was used to study the phase composition of zinc oxide powder and cements. Powder component and cement microstructure were investigated with scanning electron microscopy...
February 17, 2017: Dental Materials: Official Publication of the Academy of Dental Materials
https://www.readbyqxmd.com/read/28222045/validation-of-scaffold-design-optimization-in-bone-tissue-engineering-finite-element-modeling-versus-designed-experiments
#5
Nicholas Uth, Jens Mueller, Byran Smucker, Azizeh-Mitra Yousefi
This study reports the development of biological/synthetic scaffolds for bone tissue engineering (TE) via 3D bioplotting. These scaffolds were composed of poly(L-lactic-co-glycolic acid) (PLGA), type I collagen, and nano-hydroxyapatite (nHA) in an attempt to mimic the extracellular matrix of bone. The solvent used for processing the scaffolds was 1,1,1,3,3,3-hexafluoro-2-propanol. The produced scaffolds were characterized by scanning electron microscopy, microcomputed tomography, thermogravimetric analysis, and unconfined compression test...
February 21, 2017: Biofabrication
https://www.readbyqxmd.com/read/28221348/self-assembly-of-nanoparticles-into-biomimetic-capsid-like-nanoshells
#6
Ming Yang, Henry Chan, Gongpu Zhao, Joong Hwan Bahng, Peijun Zhang, Petr Král, Nicholas A Kotov
Nanoscale compartments are one of the foundational elements of living systems. Capsids, carboxysomes, exosomes, vacuoles and other nanoshells easily self-assemble from biomolecules such as lipids or proteins, but not from inorganic nanomaterials because of difficulties with the replication of spherical tiling. Here we show that stabilizer-free polydispersed inorganic nanoparticles (NPs) can spontaneously organize into porous nanoshells. The association of water-soluble CdS NPs into self-limited spherical capsules is the result of scale-modified electrostatic, dispersion and other colloidal forces...
March 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28218402/characterization-of-the-%C3%AE-and-p-phase-precipitates-in-the-cmsx-4-single-crystal-superalloy
#7
B Dubiel, P Indyka, T Moskalewicz, A Kruk, M Zubko, I Kalemba-Rec, K Berent
A combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning-transmission electron microscopy (STEM) using high-angle annular-dark-field (HAADF) imaging, focussed ion beam- scanning electron microscopy (FIB-SEM) tomography, selected area electron diffraction with beam precession (PED), as well as spatially resolved energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS), was used to investigate topologically close-packed (TCP) phases, occurring in the CMSX-4 superalloy subjected to high temperature annealing and creep deformation...
February 20, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28218252/dissecting-the-molecular-organization-of-the-translocon-associated-protein-complex
#8
Stefan Pfeffer, Johanna Dudek, Miroslava Schaffer, Bobby G Ng, Sahradha Albert, Jürgen M Plitzko, Wolfgang Baumeister, Richard Zimmermann, Hudson H Freeze, Benjamin D Engel, Friedrich Förster
In eukaryotic cells, one-third of all proteins must be transported across or inserted into the endoplasmic reticulum (ER) membrane by the ER protein translocon. The translocon-associated protein (TRAP) complex is an integral component of the translocon, assisting the Sec61 protein-conducting channel by regulating signal sequence and transmembrane helix insertion in a substrate-dependent manner. Here we use cryo-electron tomography (CET) to study the structure of the native translocon in evolutionarily divergent organisms and disease-linked TRAP mutant fibroblasts from human patients...
February 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28217015/the-pearl-of-fdg-pet-ct-in-preoperative-assessment-of-patients-with-potentially-operable-non-small-cell-lung-cancer-and-its-clinical-impact
#9
Boom Ting Kung, Ting Kun Au Yong, Cheuk Man Tong
The aim of this retrospective study is to evaluate the clinical impact and efficacy of fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) on management decisions for patients suffering from clinically operable non-small-cell lung cancer (NSCLC). A retrospective review of 186 potentially operable NSCLC patients who underwent whole-body PET/CT examination in 2012 was performed. The patients were further analyzed via the electronic patient record (ePR) system for relevant findings...
January 2017: World Journal of Nuclear Medicine
https://www.readbyqxmd.com/read/28216551/microscopic-characterization-of-the-brazilian-giant-samba-virus
#10
Jason R Schrad, Eric J Young, Jônatas S Abrahão, Juliana R Cortines, Kristin N Parent
Prior to the discovery of the mimivirus in 2003, viruses were thought to be physically small and genetically simple. Mimivirus, with its ~750-nm particle size and its ~1.2-Mbp genome, shattered these notions and changed what it meant to be a virus. Since this discovery, the isolation and characterization of giant viruses has exploded. One of the more recently discovered giant viruses, Samba virus, is a Mimivirus that was isolated from the Rio Negro in the Brazilian Amazon. Initial characterization of Samba has revealed some structural information, although the preparation techniques used are prone to the generation of structural artifacts...
February 14, 2017: Viruses
https://www.readbyqxmd.com/read/28215198/correlating-atom-probe-tomography-with-atomic-resolved-scanning-transmission-electron-microscopy-example-of-segregation-at-silicon-grain-boundaries
#11
Andreas Stoffers, Juri Barthel, Christian H Liebscher, Baptiste Gault, Oana Cojocaru-Mirédin, Christina Scheu, Dierk Raabe
In the course of a thorough investigation of the performance-structure-chemistry interdependency at silicon grain boundaries, we successfully developed a method to systematically correlate aberration-corrected scanning transmission electron microscopy and atom probe tomography. The correlative approach is conducted on individual APT and TEM specimens, with the option to perform both investigations on the same specimen in the future. In the present case of a Σ9 grain boundary, joint mapping of the atomistic details of the grain boundary topology, in conjunction with chemical decoration, enables a deeper understanding of the segregation of impurities observed at such grain boundaries...
February 20, 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/28215196/understanding-of-capping-effects-on-the-tip-shape-evolution-and-on-the-atom-probe-data-of-bulk-laalo3-using-transmission-electron-microscopy
#12
Chang-Min Kwak, Young-Tae Kim, Chan-Gyung Park, Jae-Bok Seol
Two challenges exist in laser-assisted atom probe tomography (APT). First, a drastic decline in mass-resolving power is caused, not only by laser-induced thermal effects on the APT tips of bulk oxide materials, but also the associated asymmetric evaporation behavior; second, the field evaporation mechanisms of bulk oxide tips under laser illumination are still unclear due to the complex relations between laser pulse and oxide materials. In this study, both phenomena were investigated by depositing Ni- and Co-capping layers onto the bulk LaAlO3 tips, and using stepwise APT analysis with transmission electron microscopy (TEM) observation of the tip shapes...
February 20, 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/28214018/assessment-of-root-canal-filling-removal-effectiveness-using-micro-computed-tomography-a-systematic-review
#13
REVIEW
Giampiero Rossi-Fedele, Hany Mohamed Aly Ahmed
INTRODUCTION: The removal of obturation materials from the root canal system is a primary objective in root canal retreatment procedures. This systematic review aims to discuss the effectiveness of different instrumentation procedures in removing root-canal filling materials assessed by micro-computed tomography. METHODS: An electronic search in PubMed and major endodontic journals was conducted using appropriate key words to identify investigations that examined the effectiveness of obturation material removal assessed by micro-computed tomography...
February 14, 2017: Journal of Endodontics
https://www.readbyqxmd.com/read/28212098/a-2-5-mw-ch-50-mcps-10-analog-channel-adaptively-biased-read-out-front-end-ic-with-low-intrinsic-timing-resolution-for-single-photon-time-of-flight-pet-applications-with-time-dependent-noise-analysis-in-90-nm-cmos
#14
Hugo Cruz, Hong-Yi Huang, Ching-Hsing Luo, Shuenn-Yuh Lee
This paper presents a 10-channel time-of-flight application-specific integrated circuit (ASIC) for positron emission tomography in a 90 nm standard CMOS process. To overcome variations in channel-to-channel timing resolution caused by mismatch and process variations, adaptive biases and a digital-to-analog converter (DAC) are utilized. The main contributions of this work are as follows. First, multistage architectures reduce the total power consumption, and detection bandwidths of analog preamplifiers and comparators are increased to 1 and 1...
February 13, 2017: IEEE Transactions on Biomedical Circuits and Systems
https://www.readbyqxmd.com/read/28210351/cross-continuum-tool-is-associated-with-reduced-utilization-and-cost-for-frequent-high-need-users
#15
Lauran Hardin, Adam Kilian, Leslie Muller, Kevin Callison, Michael Olgren
INTRODUCTION: High-need, high-cost (HNHC) patients can over-use acute care services, a pattern of behavior associated with many poor outcomes that disproportionately contributes to increased U.S. healthcare cost. Our objective was to reduce healthcare cost and improve outcomes by optimizing the system of care. We targeted HNHC patients and identified root causes of frequent healthcare utilization. We developed a cross-continuum intervention process and a succinct tool called a Complex Care Map (CCM)© that addresses fragmentation in the system and links providers to a comprehensive individualized analysis of the patient story and causes for frequent access to health services...
February 2017: Western Journal of Emergency Medicine
https://www.readbyqxmd.com/read/28208719/micro-computed-tomography-detection-of-gold-nanoparticle-labelled-mesenchymal-stem-cells-in-the-rat-subretinal-layer
#16
Pooi Ling Mok, Sue Ngein Leow, Avin Ee-Hwan Koh, Hairul Harun Mohd Nizam, Suet Lee Shirley Ding, Chi Luu, Raduan Ruhaslizan, Hon Seng Wong, Wan Haslina Wan Abdul Halim, Min Hwei Ng, Ruszymah Binti Hj Idrus, Shiplu Roy Chowdhury, Catherine Mae-Lynn Bastion, Suresh Kumar Subbiah, Akon Higuchi, Abdullah A Alarfaj, Kong Yong Then
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...
February 8, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28207240/interfaces-in-heterogeneous-catalysts-advancing-mechanistic-understanding-through-atomic-scale-measurements
#17
Wenpei Gao, Zachary D Hood, Miaofang Chi
Developing novel catalysts with high efficiency and selectivity is critical for enabling future clean energy conversion technologies. Interfaces in catalyst systems have long been considered the most critical factor in controlling catalytic reaction mechanisms. Interfaces include not only the catalyst surface but also interfaces within catalyst particles and those formed by constructing heterogeneous catalysts. The atomic and electronic structures of catalytic surfaces govern the kinetics of binding and release of reactant molecules from surface atoms...
February 16, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28206747/ultrafast-dynamics-of-manganese-iii-manganese-ii-and-free-base-bacteriochlorin-is-there-time-for-photochemistry
#18
Fabio A Schaberle, Artur R Abreu, Nuno P F Gonçalves, Gonçalo F F Sá, Mariette M Pereira, Luís G Arnaut
Manganese(III) and manganese(II) complexes of halogenated sulfonamide tetraphenylbacteriochlorins were prepared for the first time via a transmetalation reaction and shown to be stable at room temperature. The behavior of the electronic states of the paramagnetic complexes is remarkably different from those of the metal-free bacteriochlorins or diamagnetic metallobacteriochlorins. The Mn(3+) complex exhibits eight electronic transitions between different states from 300 to 1100 nm, with a very prominent band (molar absorption coefficient of ca...
February 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28206730/sinus-presurgical-evaluation-a-literature-review-and-a-new-classification-proposal
#19
Lorenzo Tavelli, Andrea E Borgonovo, Dino Re, Carlo Maiorana
Presurgical evaluation with cone beam computed tomography (CBCT) or computed tomography (CT) has become an essential tool for diagnosis and surgical planning, including maxillary sinus floor elevation. Before performing a sinus lift, the clinician's attention should not be only directed to the patency of the ostium through CBCT or CT, because many anatomical features could influence the surgical approach of sinus floor elevation. The goal of this article was to facilitate the communication between clinicians regarding the type of maxillary sinus, encourage in-depth analysis prior to surgery and reduce the risk of complications due to possible underestimation of important parameters...
February 15, 2017: Minerva Stomatologica
https://www.readbyqxmd.com/read/28199885/evaluation-of-polyesteramide-pea-and-polyester-plga-microspheres-as-intravitreal-drug-delivery-systems-in-albino-rats
#20
Tobias Peters, Seong-Woo Kim, Vinicius Castro, Krunoslav Stingl, Torsten Strasser, Sylvia Bolz, Ulrich Schraermeyer, George Mihov, MengMeng Zong, Vanessa Andres-Guerrero, Rocio Herrero Vanrell, Aylvin A Dias, Neil R Cameron, Eberhart Zrenner
PURPOSE: To study the suitability of injectable microspheres based on poly(ester amide) (PEA) or poly lactic-co-glycolic acid (PLGA) as potential vehicles for intravitreal drug delivery in rat eyes. Dexamethasone-loaded PEA microspheres (PEA + DEX) were also evaluated. METHODS: Forty male Sprague Dawley rats were divided into four groups that received different intravitreally injected microspheres: PEA group (n = 12); PLGA group (n = 12); PEA + DEX group (n = 8); and control group (no injection, n = 8)...
February 7, 2017: Biomaterials
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