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https://www.readbyqxmd.com/read/28927166/experimental-evaluation-of-respirable-dust-and-crystalline-silica-controls-during-simulated-performance-of-stone-countertop-fabrication-tasks-with-powered-hand-tools
#1
David L Johnson, Margaret L Phillips, Chaolong Qi, Anthony T Van, Danielle A Hawley
Objectives: Workers who fabricate stone countertops using hand tools are at risk of silicosis from overexposure to respirable crystalline silica. This study explored the efficacy of simple engineering controls that can be used for dust suppression during use of hand tools by stone countertop fabricators. Methods: Controlled experiments were conducted to measure whether wet methods and on-tool local exhaust ventilation (LEV) reduced respirable dust (RD) exposures during use of various powered hand tools on quartz-rich engineered stone...
July 1, 2017: Annals of Work Exposures and Health
https://www.readbyqxmd.com/read/28926074/mechanisms-for-c-sp-2-si-activation-of-aryltrimethylsilyl-groups-in-palladium-catalysed-couplings
#2
Waqar Rauf, John M Brown
Silyl-substituted aromatic compounds can participate as the electrophilic component in palladium-catalysed cross-couplings, and reactivity is enhanced by a neighbouring silyl-group. Products analogous to those obtained from C-H activation chemistry are accessible by this means with the additional benefit of regiochemistry defined by the site of silyl substitution. DFT studies described here show that the mechanism of C-Si cleavage is distinct from previously recognised mechanisms for C-H cleavage, with a cascade of silyl intermediates en route to a stable product...
September 19, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28926044/running-out-of-lithium-a-route-to-differentiate-between-capacity-losses-and-active-lithium-losses-in-lithium-ion-batteries
#3
Florian Holtstiege, Andrea Wilken, Martin Winter, Tobias Placke
Active lithium loss (ALL) resulting in a capacity loss (QALL), which is caused by lithium consuming parasitic reactions like SEI formation, is a major reason for capacity fading and, thus, for a reduction of the usable energy density of lithium-ion batteries (LIBs). QALL is often equated with the accumulated irreversible capacity (QAIC). However, QAIC is also influenced by non-lithium consuming parasitic reactions, which do not reduce the active lithium content of the cell, but induce a parasitic current. In this work, a novel approach is proposed in order to differentiate between QAIC and QALL...
September 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28925710/highly-localized-strain-in-a-mos2-au-heterostructure-revealed-by-tip-enhanced-raman-spectroscopy
#4
Mahfujur Rahaman, Raul D Rodriguez, Gerd Plechinger, Stefan Moras, Christian Schüller, Tobias Korn, Dietrich R T Zahn
Tip-enhanced Raman spectroscopy (TERS) has been rapidly improved over the last decade and opened up opportunities to study phonon properties of materials at the nanometer scale. In this contribution we report on tip-enhanced Raman spectroscopy (TERS) of an ultra-thin MoS2 flake on a nanostructured Au on silicon surface forming a two-dimensional (2D) crystal/plasmonic heterostructure. Au nanostructures (shaped in triangles) are prepared by nanosphere lithography and then MoS2 is mechanically exfoliated on top of them...
September 19, 2017: Nano Letters
https://www.readbyqxmd.com/read/28925108/development-of-a-reliable-and-reproducible-phantom-manufacturing-method-using-silica-microspheres-in-silicone
#5
Charlotte Maughan Jones, Peter R Munro
Optically scattering phantoms composed of silica microspheres embedded in an optically clear silicone matrix were manufactured using a previously developed method. Multiple problems, such as sphere aggregation, adsorption to the cast, and silicone shrinkage, were, however, frequently encountered. Solutions to these problems were developed and an improved method, incorporating these solutions, is presented. The improved method offers excellent reliability and reproducibility for creating phantoms with uniform scattering coefficient...
September 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28924443/bilateral-giant-retinal-tear-and-sequential-vitrectomy
#6
Mushawiahti Mustapha, Edward Roufail Franzco
PURPOSE: To describe the excellent outcome of surgery for bilateral giant retinal tears (GRTs) with better options of endotamponade. METHODS: This is a case report of a 62-year-old man who presented with bilateral GRTs and associated retinal detachment. The tear in the right eye was supero-temporal and silicone oil was used as an endotamponade. The tear in the left eye was infero-temporal and perfluorocarbon liquid was used as an endotamponade. RESULTS: The outcome at 6 months after surgery was excellent with visual acuities of 6/6 in both eyes...
May 2017: Case Reports in Ophthalmology
https://www.readbyqxmd.com/read/28924422/femtosecond-laser-assisted-cataract-surgery-in-vitrectomized-eye-with-posterior-chamber-phakic-intraocular-lens
#7
Natalia Anisimova, Boris Malyugin, Lisa B Arbisser, Nikolay Sobolev
We describe a case of femtosecond laser-assisted cataract surgery (FLACS) in an eye with multiple comorbidities, including retinal detachment surgery, high myopia, posterior chamber phakic intraocular lens (PC pIOL) and residual, emulsified, silicone oil located in the anterior chamber. FLACS was affected by the optical blockage, but the incomplete capsular tear was recoverable. The case suggests that silicone oil bubbles concentrated at the dome of the posterior corneal surface, along with the PC pIOL optic edges and scars after corneal astigmatic relaxing incisions can lead to incomplete anterior capsulotomy...
2017: Digital Journal of Ophthalmology: DJO
https://www.readbyqxmd.com/read/28924327/direct-comparison-of-time-resolved-terahertz-spectroscopy-and-hall-van-der-pauw-methods-for-measurement-of-carrier-conductivity-and-mobility-in-bulk-semiconductors
#8
Brian G Alberding, W Robert Thurber, Edwin J Heilweil
Charge carrier conductivity and mobility for various semiconductor wafers and crystals were measured by ultrafast above bandgap, optically excited Time-Resolved Terahertz Spectroscopy (TRTS) and Hall Van der Pauw contact methods to directly compare these approaches and validate the use of the non-contact optical approach for future materials and in-situ device analyses. Undoped and doped silicon (Si) wafers with resistances varying over six orders of magnitude were selected as model systems since contact Hall measurements are reliably made on this material...
July 2017: Journal of the Optical Society of America. B, Optical Physics
https://www.readbyqxmd.com/read/28922882/microsurgical-anatomy-of-the-interfascial-vein-its-significance-in-the-interfascial-dissection-of-the-pterional-approach
#9
Alvaro Campero, Pablo Ajler, Martín Paíz, Ramiro López Elizalde
BACKGROUND: The pterional approach (PA), together with its variants, is still one of the most common methods used by surgeons to reach the anterior and middle cranial base. A highly important technical detail during a PA is the preservation of the frontotemporal branch of the facial nerve, which can be achieved through an interfascial dissection. OBJECTIVE: To describe the anatomy of the interfascial vein (IFV), highlighting its recognition as a significant anatomic reference to perform an interfascial dissection (IFD)...
October 1, 2017: Operative Neurosurgery (Hagerstown, Md.)
https://www.readbyqxmd.com/read/28922616/novel-testing-for-corrosion-of-glass-ceramics-for-dental-applications
#10
J F Esquivel-Upshaw, F Ren, S M Hsu, F Y Dieng, D Neal, A E Clark
The effects of pH cycling immersion on the corrosion of glass-based ceramic materials were investigated by examining the silicon release level in the immersion solution and the surface morphology of the ceramic after immersion. The hypothesis that pH cycling causes more surface degradation than constant immersion was tested. An inductively coupled plasma atomic emission spectrometer was used for Si ion concentration determination and scanning electron microscopy for surface morphology analyses. Two pH cycling sequences (pH 2, 7, 10 and pH 10, 2, 7) were employed in this study...
September 1, 2017: Journal of Dental Research
https://www.readbyqxmd.com/read/28922601/substrate-dependence-of-the-freezing-dynamics-of-supercooled-water-films-a-high-speed-optical-microscope-study
#11
Elzbieta Pach, Laura Rodríguez, Albert Verdaguer
The freezing of supercooled water films on silicon-based surfaces was investigated using a high-speed camera coupled to an optical microscope. We were able to study in detail the two phases or stages in during water freezing; the first stage, faster, when dendritic grow occurs co-planar with the cold surface of the substrate and the second stage, slower, when the ice formed on the surface grows vertically until all the film is frozen. Several differentiated processes were identified during the freezing: two dimensional dendrite growing on the substrate interface, vertical dendrite growing, formation and evolution of ice domains, trapping of air bubbles in ice and freezing of the water film surface...
September 18, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28922543/in-vitro-and-in-vivo-degradation-of-microfiber-bioresorbable-coronary-scaffold
#12
Chi-Hung Huang, Sheng-Yang Lee, Sonida Horng, Louis-Georges Guy, Ting-Bin Yu
The degradation of Mirage Bioresorbable Microfiber Scaffold was evaluated in vitro and in vivo. The degradation in polymer molecular weight (MW), strut morphology, and integrity was accessed using gel permeation chromatography (GPC), X-ray micro-computed tomography (micro-CT) evaluation. To simulate the physiological degradation in vitro, scaffolds were deployed in silicone mock vessels connected to a peristaltic pumping system, which pumps 37°C phosphate-buffered saline (PBS, pH 7.4) at a constant rate. At various time points (30D, 60D, 90D, 180D, 270D, and 360D), the MW of microfibers decreased to 57...
September 18, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/28921989/universal-calibration-of-computationally-predicted-n-1s-binding-energies-for-interpretation-of-xps-experimental-measurements
#13
Jing Zhao, Fei Gao, Sidharam Pundlik Pujari, Han Zuilhof, Andrew Teplyakov
Computationally predicted N 1s core level energies are commonly used to interpret the experimental measurements obtained with X-ray photoelectron spectroscopy. This work compares the application of Koopmans' theorem to core electrons using the B3LYP functional with two commonly used basis sets, analyses the factors relevant to the comparison of the computational with experimental data, and presents several correlations that allow an accurate prediction of the N 1s binding energy. The first correlation is obtained with a series of known nitrogen-containing functional groups on well-characterized organic monolayers...
September 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28921952/nano-air-seeds-trapped-in-mesoporous-janus-nanoparticles-facilitate-cavitation-and-enhance-ultrasound-imaging
#14
Konstantin Tamarov, Andrey Sviridov, Wujun Xu, Markus Malo, Valery Andreev, Victor Yu Timoshenko, Vesa-Pekka Lehto
The current contrast agents utilized in ultrasound (US) imaging are based on microbubbles which, however, suffer from a short lifetime in the systemic circulation. The present study introduces a new type of contrast agents for US imaging based on bioresorbable Janus nanoparticles (NPs) that are able to generate microbubbles in situ under US radiation for extended time. The Janus NPs were fabricated from porous silicon (PSi) that was modified via a nanostopper technique. The technique was exploited to prepare PSi NPs which had hydrophobic pore walls (inner face) while the external surfaces of the NPs (outer face) were hydrophilic...
September 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28921947/large-scale-fabrication-of-silicon-nanowires-for-solar-energy-applications
#15
Bing-Chang Zhang, Jiansheng Jie, Xiujuan Zhang, Xue-Mei Ou, Xiao-Hong Zhang
The development of silicon (Si) materials during the past decades has boosted up the prosperity of modern semiconductor industry. In comparison with the bulk Si materials, Si nanowires (SiNWs) possess superior structural, optical and electrical properties and have attracted increasing attention in solar energy applications. To achieve the practical applications of SiNWs, both large-scale synthesis of SiNWs at low cost and rational design of energy conversion devices with high efficiency are the prerequisite...
September 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28921944/plasmonic-silicon-quantum-dots-enabled-high-sensitivity-ultra-broadband-photodetection-of-graphene-based-hybrid-phototransistors
#16
Zhenyi Ni, Lingling Ma, Sichao Du, Yang Xu, Meng Yuan, Hehai Fang, Zhen Wang, Mingsheng Xu, Dongsheng Li, Jianyi Yang, Weida Hu, Xiaodong Pi, Deren Yang
Highly sensitive photodetection even approaching the single-photon level is critical to many important applications. Graphene-based hybrid phototransistors are particularly promising for high-sensitivity photodetection because they have high photoconductive gain due to the high mobility of graphene. Given their remarkable optoelectronic properties and solution-based processing, colloidal quantum dots (QDs) have been preferentially used to fabricate graphene-based hybrid phototransistors. However, the resulting QD/graphene hybrid phototransistors face the challenge of extending the photodetection into the technologically important mid-infrared (MIR) region...
September 18, 2017: ACS Nano
https://www.readbyqxmd.com/read/28918299/the-prosthetic-rehabilitation-of-a-patient-with-a-lateral-postsurgical-defect-using-a-2-piece-magnet-retained-facial-prosthesis-a-clinical-report
#17
Kariem M Elhelow, Yasser E Al-Thobaiti, Abdurabu A Gomawi
Nonsurgical prosthetic interventions are often proposed after repeated grafts have failed to restore irradiated facial defects. This report describes a facial prosthetic reconstruction following ablative surgery for a sizable facial tumor by using a novel custom-made magnet-bearing substructure, which connected with an exposed part of the mandibular reconstruction plate. The defect involved the entire left lower part of the face and angle of the mentum. This reconstructive technique, together with an added surface texture with hair-like silicone strands, effectively addressed the cosmetic needs of the patient...
September 14, 2017: Journal of Prosthetic Dentistry
https://www.readbyqxmd.com/read/28917803/atp-mediated-rolling-circle-amplification-and-opening-dna-gate-for-drug-delivery-to-cell
#18
Yujie Wang, Xinxin Shang, Jia Liu, Yingshu Guo
Here, we have developed a facile fluorometric system for the detection of adenosine triphosphate (ATP) by a rolling circle amplification (RCA) based on proximity ligation mediated amplification, and simultaneously achieved the release of the anticancer drug doxorubicin (DOX) through the mesoporous silicon system. Once the ATP molecule is present, the linker DNA will be released from the graphene oxide (GO) surface and hybridized to the template DNA of the GO surface joining with ligation enzyme. RCA reaction is followed by the addition of the phi29 DNA polymerase...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917144/silicon-improves-seed-germination-and-alleviates-drought-stress-in-lentil-crops-by-regulating-osmolytes-hydrolytic-enzymes-and-antioxidant-defense-system
#19
Sajitha Biju, Sigfredo Fuentes, Dorin Gupta
Silicon (Si) has been widely reported to have beneficial effect on mitigating drought stress in plants. However, the effect of Si on seed germination under drought conditions is still poorly understood. This research was carried out to ascertain the role of Si to abate polyethylene glycol-6000 mediated drought stress on seed germination and seedling growth of lentil. Results showed that drought stress significantly decreased the seed germination traits and increased the concentration of osmolytes (proline, glycine betaine and soluble sugars), reactive oxygen species (hydrogen peroxide and superoxide anion) and lipid peroxides in lentil seedlings...
September 5, 2017: Plant Physiology and Biochemistry: PPB
https://www.readbyqxmd.com/read/28916983/surface-changes-of-nanotopography-by-carbon-ion-implantation-to-enhance-the-biocompatibility-of-silicone-rubber-an-in-vitro-study-of-the-optimum-ion-fluence-and-adsorbed-protein
#20
Xianhui Li, Xin Zhou, Yao Chen, Shu Yu, Xin Chen, Xin Xia, Xiaohua Shi, Yiming Zhang, Dongli Fan
Lower cellular adhesion and dense fibrous capsule formation around silicone breast implants caused by lower biocompatibility is a serious clinical problem. Preliminary work has shown that ion implantation enhances cell adhesion. Whether the biocompatibility is further enhanced by higher doses of carbon ion implantation and the mechanism by which ion implantation enhances biocompatibility remain unclear. In this study, five doses of carbon ions, which gradually increase, were implanted on the surface of silicone rubber and then the surface characteristics were surveyed...
September 15, 2017: Journal of Materials Science. Materials in Medicine
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