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New materials

Catherine Pirard, Corinne Charlier
Recent and reliable human biomonitoring data on brominated flame retardants (BFRs), either legacy or new BFRs, are still needed to assess human exposure. The aim of this work was therefore to develop and validate an accurate, fast and user-friendly analytical strategy for the determination of 15 legacy and novel BFRs in human serum namely 8 polybrominated diphenylethers (BDE-28, -47, -99, -100, -153, -154, -183, and -209), 1 hexabromobiphenyl (PBB-153), and 6 novel BFRs (pentabromotoluene, hexabromobenzene, pentabromoethylbenzene, 2-ethylhexy-2,3,4,5-tetrabromobenzoate, 1,2-bis(2,4,6-tribromophenoxy)ethane, and decabromodiphenylethane)...
August 9, 2018: Chemosphere
Faizan Ahmad, Ra J Prabhu, Jun Liao, Shwe Soe, Michael D Jones, Jonathan Miller, Parker Berthelson, Daniel Enge, Katherine M Copeland, Samar Shaabeth, Richard Johnston, Ian Maconochie, Peter S Theobald
Neonatal heart disorders represent a major clinical challenge, with congenital heart disease alone affecting 36,000 new-borns annually within the European Union. Surgical intervention to restore normal function includes the implantation of synthetic and biological materials; however, a lack of experimental data describing the mechanical behaviour of neonatal cardiac tissue is likely to contribute to the relatively poor short- and long-term outcome of these implants. This study focused on characterising the mechanical behaviour of neonatal cardiac tissue using a porcine model, to enhance the understanding of how this differs to the equivalent mature tissue...
July 29, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Emmanuelle Casanova, Timothy David James Knowles, Christopher Williams, Matthew P Crump, Richard Peter Evershed
Preparative capillary gas chromatography (pcGC) is widely used for the isolation of single compounds for radiocarbon determinations. While being effective at isolating compounds, there are still genuine concerns relating to contamination associated with the isolation procedure, such as incomplete removal of solvent used to recover isolated samples from the traps and cross-contamination, which can lead to erroneous 14C determinations. Herein we describe new approaches to identifying and removing these two sources of contamination...
August 17, 2018: Analytical Chemistry
Thomas S King, Ramaswamy Sharma, Jeff Jackson, Kristin R Fiebelkorn
This descriptive article describes the use of clinical case-based portfolios in histopathology teaching laboratories in conjunction with virtual microscopy not only to integrate histology and pathology disciplines for first and second year medical students but also to stimulate student engagement, promote self-directed and group-based learning and enhance student-to-student interaction in a structured manner. Portfolios consisted of PowerPoint files encompassing four to five clinical case studies relevant to the topics covered that week...
August 17, 2018: Anatomical Sciences Education
Qiaofeng Yao, Xun Yuan, Tiankai Chen, David Tai Leong, Jianping Xie
With continuous research efforts devoted into synthesis and characterization chemistry of functional nanomaterials in the past decades, the development of metal materials is stepping into a new era, where atom-by-atom customization of property-dictating structural attributes is expected. Herein, the state-of-the-art modulation of functional metal nanomaterials at the atomic level, by size- and structure-controlled synthesis of thiolate-protected metal (e.g., Au and Ag) nanoclusters (NCs), is exemplified. Metal NCs are ultrasmall (<3 nm) particles with hierarchical primary, secondary, and tertiary structures, reminiscent of natural proteins or enzymes...
August 17, 2018: Advanced Materials
Junyong Wang, Ivan Verzhbitskiy, Goki Eda
Ultrathin layers of van der Waals inorganic semiconductors represent a new class of excitonic materials with attractive light-emitting properties. Recent observation of valley polarization, optically pumped lasing, exciton-polaritons, and single-photon emission highlights the exciting prospects for two-dimensional (2D) semiconductors for applications in novel photonic devices. Development of efficient and reliable light sources based on excitonic electroluminescence in 2D semiconductors is of fundamental importance toward the practical implementation of photonic devices...
August 17, 2018: Advanced Materials
Daniele Cardaropoli, Lorenzo Tamagnone, Alessandro Roffredo, Andrea De Maria, Lorena Gaveglio
Alveolar ridge preservation is of great importance for successful implant therapy. This study investigated the effects of a xenogeneic tridimensional collagen matrix (CM) in conjunction with deproteinized bovine bone mineral blended with 10% collagen (DBBM-C) on the healing of 12 intact extraction sockets in the esthetic area. Cone beam computed tomograpy examinations revealed nearly stable alveolar ridge dimensions (> 90% of the ridge horizontal dimension was preserved). New bone formation of approximately 45% and adequate resorption of the grafted material were histologically observed...
2018: International Journal of Periodontics & Restorative Dentistry
Hongyu Jing, Lingyun Liu, Junfeng Zhou, Hanxin Yao
BACKGROUND Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease characterized by long-term breathing problems and poor airflow. COPD can progress to persistent decline of pulmonary function. This study explored the effect of CXCL10 on COPD induced by cigarette smoke (CS) and its underlying mechanism. MATERIAL AND METHODS Wild-type (WT) mice were randomly assigned into 3 groups: the control group, the CS group, and the intervention group. Mice in the CS group were exposed to CS and mice in the CXCL10 group were exposed to CS and CXCL10 neutralizing antibody...
August 17, 2018: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
Simone Ciarella, Francesco Sciortino, Wouter G Ellenbroek
We propose a coarse-grained model to investigate stress relaxation in star-polymer networks induced by dynamic bond-exchange processes. We show how the swapping mechanism, once activated, allows the network to reconfigure, exploring distinct topological configurations, all of them characterized by complete extent of reaction. Our results reveal the important role played by topological defects in mediating the exchange reaction and speeding up stress relaxation. The model provides a representation of the dynamics in vitrimers, a new class of polymers characterized by bond-swap mechanisms which preserve the total number of bonds, as well as in other bond-exchange materials...
August 3, 2018: Physical Review Letters
Saima A Siddiqui, Jiahao Han, Joseph T Finley, Caroline A Ross, Luqiao Liu
Owing to the difficulty in detecting and manipulating the magnetic states of antiferromagnetic materials, studying their switching dynamics using electrical methods remains a challenging task. By employing heavy-metal-rare-earth-transition-metal alloy bilayers, we experimentally study current-induced domain wall dynamics in an antiferromagnetically coupled system. We show that the current-induced domain wall mobility reaches a maximum at the angular momentum compensation point. With experiment and modeling, we further reveal the internal structures of domain walls and the underlying mechanisms for their fast motion...
August 3, 2018: Physical Review Letters
Yee Sin Ang, Hui Ying Yang, L K Ang
We identify a new universality in the carrier transport of two-dimensional (2D) material-based Schottky heterostructures. We show that the reversed saturation current (J) scales universally with temperature (T) as log(J/T^{β})∝-1/T, with β=3/2 for lateral Schottky heterostructures and β=1 for vertical Schottky heterostructures, over a wide range of 2D systems including nonrelativistic electron gas, Rashba spintronic systems, single- and few-layer graphene, transition metal dichalcogenides, and thin films of topological solids...
August 3, 2018: Physical Review Letters
Ran Chen, Amin Morteza Najarian, Niraja Kurapati, Ryan James Balla, Alexander Oleinick, Irina Svir, Christian Amatore, Richard L McCreery, Shigeru Amemiya
Applications of conducting carbon materials for highly efficient electrochemical energy devices require a greater fundamental understanding of heterogeneous electron-transfer (ET) mechanisms. This task, however, is highly challenging experimentally, because an adsorbing carbon surface may easily conceal its intrinsic reactivity through adventitious contamination. Herein, we employ nanoscale scanning electrochemical microscopy (SECM) and cyclic voltammetry to gain new insights into the interplay between heterogeneous ET and adsorption of a Co(III)/Co(II)-complex redox couple at the contamination-free surface of electron-beam-deposited carbon (eC)...
August 17, 2018: Analytical Chemistry
Minsu Gu, Jaewon Choi, Taemin Lee, Minju Park, Ik-Soo Shin, Jinkee Hong, Hyun-Wook Lee, Byeong-Su Kim
Controlling the architecture of hybrid nanomaterial electrodes is critical for understanding their fundamental electrochemical mechanisms and applying these materials in future energy conversion and storage systems. Herein, we report highly tunable electrocatalytic multilayer electrodes, composed of palladium nanoparticles (Pd NPs) supported by graphene sheets of varying lateral sizes, employing a versatile layer-by-layer (LbL) assembly method. We demonstrate that the electrocatalytic activity is highly tunable through the control of the diffusion and electron pathways within the 3-dimensional multilayer electrodes...
August 17, 2018: Nanoscale
Zhao Liu, Haidi Wang, Jiuyu Sun, Rujie Sun, Z F Wang, Jinlong Yang
Since the discovery of graphene, two-dimensional (2D) materials have paved new ways to design high-performance nanoelectronic devices. To facilitate applications of such devices, there are three key requirements that a material needs to fulfill: sizeable band gap, high carrier mobility, and robust environmental stability. However, among the most popular 2D materials studied in recent years, graphene is gapless, hexagonal boron nitride has a very large band gap, transition metal dichalcogenides have low carrier mobility, and black phosphorene is ambience-sensitive...
August 17, 2018: Nanoscale
J Martan, J Tesař, M Kučera, P Honnerová, M Benešová, M Honner
In this paper, a new measurement system and a new approach in calculation for infrared (IR) radiation investigation in quasi-simultaneous transmission laser welding of plastics are presented. The measurement system is based on a MW/SWIR (medium-wave/short-wave IR) camera and optical filters narrowing the spectral region to SWIR. The measured signals contain radiation from the melted zone in between the semitransparent and absorbing polymers, as well as radiation from the surface and interior of the semitransparent polymer...
June 20, 2018: Applied Optics
Yu-Shan Chang, Long Hsu, Kuang-Lung Huang
When UV-curable material is used with a spherical glass lens, it is classified as a hybrid lens and can provide a new degree of freedom in designing a lens system. This method is used to explore the optical limitation of an ultrawide-angle imaging system of a folded structure, which is utilized to achieve a compact volume. The f-number and field of view of the system are 2.0 and 190°, respectively. Diffraction-limited performance is achieved within a field of view of 80° with Strehl ratios greater than approximately 80%...
July 1, 2018: Applied Optics
Marina Medhat, Yasser M El-Batawy, Alaa K Abdelmageed, Ezzeldin A Soliman
In this paper, novel gear-shaped nanoparticles are introduced for the first time to enhance the photovoltaic (PV) efficiency. This has been achieved via increasing the overall power absorption by the PV semiconductor material in both visible and near-infrared ranges. The modes of the new gear-shaped nanoparticles are investigated. A parametric study has been performed which demonstrates how the design parameters of the proposed nanoparticles can be engineered for best overall power absorption within a Si surrounding medium...
July 1, 2018: Applied Optics
Jianming Yang, Patrice Twardowski, Philippe Gérard, Wenhui Yu, Joël Fontaine
In this paper, we present a detailed and rigorous study of cylindrical harmonic Fresnel lenses (HFLs) using the finite difference time domain method (FDTD) and angular spectrum method (ASM). The HFL is a kind of diffractive lens that can have maximum diffraction efficiency at several discrete harmonic wavelengths, which is suitable for some broadband applications. Previous studies on HFLs were investigated mainly in the domain of paraxial approximation. By using our proposed calculation method, we have determined the efficiency, focal length, maximum focus intensity, and full width at half maximum (FWHM) of the focal spot for several harmonic numbers and for F-numbers of 0...
July 1, 2018: Applied Optics
Qingyang Fan, Wenzhu Zhang, Sining Yun, Jie Xu, Yanxing Song
The structural, mechanical, elastic anisotropy and electronic properties, together with the stability, effective mass of holes and electrons for XN (X=Al, Ga, In) in the Pnma phase are investigated using density functional theory calculations. The elastic constants and the phonon spectra all manifest III-nitride polymorphs: XN (X=Al, Ga, In) in the Pnma phase in this work are mechanically and dynamically stable at ambient pressure. Al atoms, Ga atoms and In atoms lead to new electrical and band-gap properties: XN (X=Al, Ga, In) in the Pnma phase are all semiconductor materials with direct band gaps of 4...
August 17, 2018: Chemistry: a European Journal
Bo-Tao Xin, Bianca D M van Tol, Huib Ovaa, Paul P Geurink
The development of γ-thionorleucine (ThioNle) as a handle for native chemical ligation-desulfurization is reported here. ThioNle is a new addition to the expanding thiolated amino acid toolbox and serves as a methionine substitute in NCL with the advantage that it lacks the undesirable oxidation-prone thioether moiety. Its usefulness for N-terminal ubiquitination is demonstrated by efficient preparation of fully synthetic linear diubiquitin with preserved protein folding compared to the expressed material...
August 17, 2018: Organic & Biomolecular Chemistry
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