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Calum McDonald, Chengsheng Ni, Vladimir Švrček, Mickaël Lozac'h, Paul A Connor, Paul Maguire, John T S Irvine, Davide Mariotti
Organometal trihalide perovskite solar cells have attracted monumental attention in recent years. Today's best devices, based on a three-dimensional perovskite structure of corner-sharing PbI6 octahedra, are unstable, toxic, and display hysteresis in current-voltage measurements. We present zero-dimensional organic-inorganic hybrid solar cells based on methylammonium iodo bismuthate (CH3NH3)3(Bi2I9) (MABI) comprising a Bi2I9 bioctahedra and observe very low hysteresis for scan rates in the broad range of 150 mV s(-1) to 1500 mV s(-1) without any interfacial layer engineering...
November 23, 2017: Nanoscale
Luciane Calabria, Jesum A Fernandes, Pedro Migowski, Fabiano Bernardi, Daniel L Baptista, Rafael Leal, Thomas Grehl, Jairton Dupont
Surface-clean Au nanoparticles (NPs) confined in films of ionic liquids (ILs) can be easily fabricated by sputtering deposition. A silicon wafer coated with films of both hydrophobic (bis((trifluoromethyl)sulfonyl)amide, NTf2(-)) and hydrophilic (tetrafluoroborate, BF4(-)) imidazolium-based ILs forms an 'ionic carpet-like' structure that can be easily decorated with Au NPs of 5.1 and 6.5 nm mean diameter, respectively. The depth profile distribution of the Au NPs depends on the arrangement of the IL, which is controlled mainly by the anion volume...
November 23, 2017: Nanoscale
Siham M Hussein, Iain F Crowe, Nick Clark, Milan Milosevic, Aravind Vijayaraghavan, Frederic Y Gardes, Goran Z Mashanovich, Matthew P Halsall
We present a Raman mapping study of monolayer graphene G and 2D bands, after integration on silicon strip-waveguide-based micro-ring resonators (MRRs) to characterize the effects of the graphene transfer processes on its structural and optoelectronic properties. Analysis of the Raman G and 2D peak positions and relative intensities reveal that the graphene is electrically intrinsic where it is suspended over the MRR but is moderately hole-doped where it sits on top of the waveguide structure. This is suggestive of Fermi level 'pinning' at the graphene-silicon heterogeneous interface, and we estimate that the Fermi level shifts down by approximately 0...
November 22, 2017: Nanoscale Research Letters
Doron Klein, Eran Hadad, Itay Wiser, Omer Wolf, Ortal Itzhaki Shapira, Shir Fucks, Lior Heller
BACKGROUND: Silicone breast implants from the French manufacturer Poly Implants Prosthèse (PIP) were recalled from the European market after the French regulator has revealed the implants contain non-medical-grade silicone filler. In December 2011, following a large increase in reported rupture rate and a possible cancer risk, the French Ministry of Health recommended consideration of the PIP explantation, regardless of their condition. In 2012, the Israel Ministry of Health recommended to replace the implants only upon suspected implant rupture...
November 21, 2017: Annals of Plastic Surgery
Reed Nieman, Adélia J A Aquino, Trevor P Hardcastle, Jani Kotakoski, Toma Susi, Hans Lischka
Silicon represents a common intrinsic impurity in graphene, bonding to either three or four carbon neighbors, respectively, in a single or double carbon vacancy. We investigate the effect of the latter defect (Si-C4) on the structural and electronic properties of graphene using density functional theory. Calculations based both on molecular models and with periodic boundary conditions have been performed. The two-carbon vacancy was constructed from pyrene (pyrene-2C) which was then expanded to circumpyrene-2C...
November 21, 2017: Journal of Chemical Physics
Yosslen Aray, Ricardo Paredes, Luis Javier Álvarez, Alejandro Martiz
The electron density localization in insulator and semiconductor elemental cubic materials with diamond structure, carbon, silicon, germanium, and tin, and good metallic conductors with face centered cubic structure such as α-Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au, was studied using a localized electrons detector defined in the local moment representation. Our results clearly show an opposite pattern of the electron density localization for the cubic ceramic and transition metal materials. It was found that, for the elemental ceramic materials, the zone of low electron localization is very small and is mainly localized on the atomic basin edges...
June 14, 2017: Journal of Chemical Physics
Eitam Arnon, Eran Rabani, Daniel Neuhauser, Roi Baer
An ab initio Langevin dynamics approach is developed based on stochastic density functional theory (sDFT) within a new embedded saturated fragment formalism, applicable to covalently bonded systems. The forces on the nuclei generated by sDFT contain a random component natural to Langevin dynamics, and its standard deviation is used to estimate the friction term on each atom by satisfying the fluctuation-dissipation relation. The overall approach scales linearly with the system size even if the density matrix is not local and is thus applicable to ordered as well as disordered extended systems...
June 14, 2017: Journal of Chemical Physics
Yi Yao, Yosuke Kanai
We present the implementation and performance of the strongly constrained and appropriately normed, SCAN, meta-GGA exchange-correlation (XC) approximation in the planewave-pseudopotential (PW-PP) formalism using the Troullier-Martins pseudopotential scheme. We studied its performance by applying the PW-PP implementation to several practical applications of interest in condensed matter sciences: (a) crystalline silicon and germanium, (b) martensitic phase transition energetics of phosphorene, and (c) a single water molecule physisorption on a graphene sheet...
June 14, 2017: Journal of Chemical Physics
Ihor Zadorozhnyi, Jing Li, Sergii Pud, Hanna Hlukhova, Volodymyr Handziuk, Yurii Kutovyi, Mykhailo Petrychuk, Svetlana Vitusevich
In the present study, transport properties and single trap phenomena in silicon nanowire (NW) field-effect transistors (FETs) are reported. The dynamic behavior of drain current in NW FETs studied before and after gamma radiation treatment deviates from the predictions of the Shockley-Read-Hall model and is explained by the concept taking into account an additional energy barrier in the accumulation regime. It is revealed that dynamics of charge exchange processes between single trap and nanowire channel strongly depend on gamma radiation treatment...
November 22, 2017: Small
E N Verigo, I A Filatova, O N Tkachenko
AIM: rectification of indications and contraindications for ectoprosthetics and exploration of its potential as a modern rehabilitation modality. MATERIAL AND METHODS: Here are summarized the results of 89 cases of facial reconstruction with prosthetic means in trauma patients and those who had had congenital or oncological pathology and in whom other methods of rehabilitation were unable to remedy the defect within the orbital region. RESULTS: The indications and contraindications for facial prosthetics as well as the conditions, under which this type of medical and social rehabilitation can be carried out, were clarified...
2017: Vestnik Oftalmologii
E G Kazimirova, V V Shiryaev, P V Lyskin, E Yu Kramarenko
Scleral buckling (SB) has been regaining its popularity in the treatment of retinal detachments. On large clinical material, it has been proved to be the technique of choice in phakic patients with retinal detachment of moderate severity. A combined procedure that incorporates features of episcleral as well as intravitreal surgeries has also become widely used. Aim - to investigate the prospects for increasing technical potential of SB, particularly, to investigate the possibility of additional atraumatic mechanical fixation of the retina from within the vitreous cavity...
2017: Vestnik Oftalmologii
Taisuke Kojima
Quantitative analysis of biomolecular adsorption on a substrate is crucial for understanding biomolecular interactions. A quartz crystal microbalance (QCM) is a highly sensitive device to detect such interactions based on mass. However, the physicochemical analysis by the QCM alone often leads to overestimation of the actual adsorbed mass. Here a combined reflectometric interference spectroscopy (RIfS) and QCM is developed to simultaneously analyze adsorption of biomolecules. The RIfS detects the adsorbed mass based on the reflectance and predicts the adsorbed condition by modeling the reflection spectra using the transfer matrix method...
November 22, 2017: Analytical Chemistry
Sofia Arshavsky Graham, Naama Massad-Ivanir, Federico Paratore, Thomas Scheper, Moran Bercovici, Ester Segal
Porous silicon (PSi) nanomaterials have been widely studied as label-free optical biosensors for proteins detection. However, these biosensors' performance, specifically in terms of their sensitivity (which is typically in the micromolar range), is insufficient for many applications. Herein, we present a proof-of-concept application of the electrokinetic isotachophoresis (ITP) technique for real-time pre-concentration of a target protein on a PSi biosensor. With ITP, a highly concentrated target zone is delivered to the sensing area, where the protein target is captured by immobilized aptamers...
November 22, 2017: ACS Sensors
Yumiko Sakuragi, Yu Sawada, Motonobu Nakamura
No abstract text is available yet for this article.
December 2017: Contact Dermatitis
Thatyane Pereira de Sousa, Alan Carlos Alves de Souza, Marta Cristina Corsi de Filippi, Anna Cristina Lanna, Marcio Vinicius Cortês, Hugo Alves Pinheiro, Gisele Barata da Silva
Upland rice can overcome major challenges through the insertion of silicate fertilization and the presence of plant growth-promoting microorganisms (PGPMs) during its cultivation, as these factors promote an increase in vigor and plant disease resistance. Two consecutive experiments were conducted to evaluate the beneficial effects of silicon fertilization combined with the PGPM, Pseudomonas fluorensces, Burkholderia pyrrocinia, and a pool of Trichoderma asperellum, in upland rice seedlings, cultivar BRS Primavera CL: (a) E1, selecting PGPM type and Si doses for rice growth promotion and leaf blast supression, and (b) E2, evaluating physiological characteristics correlated with mechanisms involved in the higher vegetative growth in highlighted treatments from E1...
November 21, 2017: Environmental Science and Pollution Research International
Stefan Kuhn, Benjamin A Stickler, Alon Kosloff, Fernando Patolsky, Klaus Hornberger, Markus Arndt, James Millen
Nanomechanical devices have attracted the interest of a growing interdisciplinary research community, since they can be used as highly sensitive transducers for various physical quantities. Exquisite control over these systems facilitates experiments on the foundations of physics. Here, we demonstrate that an optically trapped silicon nanorod, set into rotation at MHz frequencies, can be locked to an external clock, transducing the properties of the time standard to the rod's motion with a remarkable frequency stability f r/Δf r of 7...
November 21, 2017: Nature Communications
Mark J McLean, William A Osborn
Compared to more commonly used strain measurement techniques, electron backscatter diffraction (EBSD) offers improved spatial resolution and measurement sensitivity. Additionally, EBSD can provide the full deformation tensor, whereas other techniques, such as digital image correlation (DIC), are limited to only in-plane strains and rotations. In this work, EBSD was used to measure strains and rotations in-situ during testing of a single-crystal silicon micromechanical test specimen. The theta-like specimen geometry was chosen due to the complex and spatially-varying strain states that exist in the circular frame of the sample during testing, as well as the nominally uniform strains in the central web...
November 14, 2017: Ultramicroscopy
Jiazhen Sheng, Ju-Hwan Han, Wan-Ho Choi, Jozeph Park, Jin-Seong Park
Silicon dioxide (SiO2) films were synthesized by plasma enhanced atomic layer deposition (PEALD) using BTBAS (bis(tertiarybutylamino) silane) as the precursor and O2 plasma as the reactant, at a temperature range of 50 to 200 °C. While dielectric constant values larger than 3.7 are obtained at all deposition temperatures, the leakage current levels are drastically reduced to below 10-12 A at temperatures above 150 °C, which are similar to those obtained in thermally oxidized and PECVD grown SiO2. Thin film transistors (TFTs) based on In-Sn-Zn-O (ITZO) semiconductors were fabricated using thermal SiO2, PECVD SiO2 and PEALD SiO2 grown at 150 °C as the gate dielectrics, and superior device performance and stability are observed in the last case...
November 21, 2017: ACS Applied Materials & Interfaces
Felix S Geitner, Thomas F Fässler
The reaction of NHC(Dipp)CuCl with the silicide phases A12Si17 (A: K, K/Rb, Rb) in NH3(l) yields [NHC(Dipp)Cu(η(4)-Si9)](3-) (1) as only the third example of a substituted [Si9] cluster. The corresponding salts A3[A(2.2.2-crypt)]3[NHC(Dipp)Cu(η(4)-Si9)]2·26NH3 (A: K (1a), K/Rb (1b), Rb (1c)) crystallize isostructurally in the space group P1[combining macron] and have been characterized by single crystal structure determination. ESI-MS and NMR experiments reveal that the anion [NHC(Dipp)Cu(η(4)-Si9)](3-) can also be transferred to pyridine or acetonitrile solutions at low temperature...
November 21, 2017: Chemical Communications: Chem Comm
Rafael Schlögel Cunali, Rafaella Caramori Saab, Gisele Maria Correr, Leonardo Fernandes da Cunha, Bárbara Pick Ornaghi, André V Ritter, Carla Castiglia Gonzaga
Marginal and internal adaptation is critical for the success of indirect restorations. New imaging systems make it possible to evaluate these parameters with precision and non-destructively. This study evaluated the marginal and internal adaptation of zirconia copings fabricated with two different systems using both silicone replica and microcomputed tomography (micro-CT) assessment methods. A metal master model, representing a preparation for an all-ceramic full crown, was digitally scanned and polycrystalline zirconia copings were fabricated with either Ceramill Zi (Amann-Girrbach) or inCoris Zi (Dentslpy-Sirona), n=10...
July 2017: Brazilian Dental Journal
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