bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-linear effects and thermoelectric efficiency of quantum dot-based single-electron transistors
Authors: Talbo Vincent , Saint-Martin Jérôme , Retailleau Sylvie , Dollfus Philippe 
Published: October 2017

AbstractBy means of advanced numerical simulation, the thermoelectric properties of a Si-quantum dot-based single-electron transistor operating in sequential tunneling regime are investigated in terms of figure of merit, efficiency and power. By taking into account the phonon-induced collisional broadening of energy levels in the quantum dot, both heat and electrical currents are computed in a voltage range beyond the linear response. Using our homemade code consisting in a 3D Poisson-Schrödinger solver and the resolution of the Master equation, the Seebeck coefficient at low bias voltage appears to be material independent and nearly independent on the level broadening, which makes this device promising for metrology applications as a nanoscale standard of Seebeck coefficient. Besides, at higher voltage bias, the non-linear characteristics of the heat current are shown to be related to the multi-level effects. Finally, when considering only the electronic contribution to the thermal conductance, the single-electron transistor operating in generator regime is shown to exhibit very good efficiency at maximum power.
Identification and characterization of a novel β-glucosidase via metagenomic analysis of Bursaphelenchus xylophilus and its microbial flora
Authors: Zhang Lin , Fu Qiang , Li Wenpeng , Wang Bowen , Yin Xiaoyan , Liu Suyao , Xu Zhaonan , Niu Qiuhong 
Published: October 2017

Abstractβ-glucosidases catalyze the final step of cellulose hydrolysis and are essential in cellulose degradation. A β-glucosidase gene,cen502, was identified and isolated from a metagenomic library fromBursaphelenchus xylophilusvia functional screening. Analyses indicated thatcen502encodes a 465 amino acid polypeptide that contains a catalytic domain belonging to the glycoside hydrolase family 1 (GH1). Cen502 was heterologously expressed, purified, and biochemically characterized. Recombinant Cen502 displayed optimum enzymatic activity at pH 8.0 and 38 °C. The enzyme had highest specific activity to p-nitrophenyl-β-D-glucopyranoside (pNPG; 180.3 U/mg) and hadKmandVmaxvalues of 2.334 mol/ml and 9.017 μmol/min/mg, respectively. The addition of Fe2+and Mn2+significantly increased Cen502 β-glucosidase activity by 60% and 50%, respectively, while 10% and 25% loss of β-glucosidase activity was induced by addition of Pb2+and K+, respectively. Cen502 exhibited activity against a broad array of substrates, including cellobiose, lactose, salicin, lichenan, laminarin, and sophorose. However, Cen502 displayed a preference for the hydrolysis of β-1,4 glycosidic bonds rather than β-1,3, β-1,6, or β-1,2 bonds. Our results indicate that Cen502 is a novel β-glucosidase derived from bacteria associated withB. xylophilusand may represent a promising target to enhance the efficiency of cellulose bio-degradation in industrial applications.
OCT Amplitude and Speckle Statistics of Discrete Random Media
Authors: Almasian Mitra , van Leeuwen Ton G. , Faber Dirk J. 
Published: October 2017

AbstractSpeckle, amplitude fluctuations in optical coherence tomography (OCT) images, contains information on sub-resolution structural properties of the imaged sample. Speckle statistics could therefore be utilized in the characterization of biological tissues. However, a rigorous theoretical framework relating OCT speckle statistics to structural tissue properties has yet to be developed. As a first step, we present a theoretical description of OCT speckle, relating the OCT amplitude variance to size and organization for samples of discrete random media (DRM). Starting the calculations from the size and organization of the scattering particles, we analytically find expressions for the OCT amplitude mean, amplitude variance, the backscattering coefficient and the scattering coefficient. We assume fully developed speckle and verify the validity of this assumption by experiments on controlled samples of silica microspheres suspended in water. We show that the OCT amplitude variance is sensitive to sub-resolution changes in size and organization of the scattering particles. Experimentally determined and theoretically calculated optical properties are compared and in good agreement.
The influence of structural disorder and phonon on metal-to-insulator transition of VO
2
Authors: Hwang In-Hui , Jin Zhenlan , Park Chang-In , Han Sang-Wook 
Published: October 2017

AbstractWe used temperature-dependent x-ray absorption fine structure (XAFS) measurements to examine the local structural properties around vanadium atoms at the V K edge from VO2 films. A direct comparison of the simultaneously-measured resistance and XAFS regarding the VO2 films showed that the thermally-driven structural transition occurred prior to the resistance transition during a heating, while this change simultaneously occured during a cooling. Extended-XAFS (EXAFS) analysis revealed significant increases of the Debye-Waller factors of the V-O and V-V pairs in the {111} direction of the R-phase VO2 that are due to the phonons of the V-V arrays along the same direction in a metallic phase. The existance of a substantial amount of structural disorder on the V-V pairs along the c-axis in both M1 and R phases indicates the structural instability of V-V arrays in the axis. The anomalous structural disorder that was observed on all atomic sites at the structural phase transition prevents the migration of the V 3d1 electrons, resulting in a Mott insulator in the M2-phase VO2.
Mycobacterial genomic DNA from used Xpert MTB/RIF cartridges can be utilised for accurate second-line genotypic drug susceptibility testing and spoligotyping
Authors: Venter Rouxjeane , Derendinger Brigitta , de Vos Margaretha , Pillay Samantha , Dolby Tanya , Simpson John , Kitchin Natasha , Ruiters Ashley , van Helden Paul D. , Warren Robin M. , Theron Grant 
Published: October 2017

AbstractXpert MTB/RIF (Xpert) is a widely-used test for tuberculosis (TB) and rifampicin-resistance. Second-line drug susceptibility testing (DST), which is recommended by policymakers, typically requires additional specimen collection that delays effective treatment initiation. We examined whether cartridge extract (CE) from used Xpert TB-positive cartridges was, without downstream DNA extraction or purification, suitable for both genotypic DST (MTBDRplus, MTBDRsl), which may permit patients to rapidly receive a XDR-TB diagnosis from a single specimen, and spoligotyping, which could facilitate routine genotyping. To determine the limit-of-detection and diagnostic accuracy, CEs from dilution series of drug-susceptible and -resistant bacilli were tested (MTBDRplus, MTBDRsl). Xpert TB-positive patient sputa CEs (n = 85) were tested (56 Xpert-rifampicin-susceptible, MTBDRplus and MTBDRsl; 29 Xpert-rifampicin-resistant, MTBDRsl). Spoligotyping was done on CEs from dilution series and patient sputa (n = 10). MTBDRplus had high non-valid result rates. MTBDRsl on CEs from dilutions ≥103CFU/ml (CT ≤ 24, >“low” Xpert semiquantitation category) was accurate, had low indeterminate rates and, on CE from sputa, highly concordant with MTBDRsl isolate results. CE spoligotyping results from dilutions ≥103CFU/ml and sputa were correct. MTBDRsl and spoligotyping on CE are thus highly feasible. These findings reduce the need for additional specimen collection and culture, for which capacity is limited in high-burden countries, and have implications for diagnostic laboratories and TB molecular epidemiology.
Structural dissection of human metapneumovirus phosphoprotein using small angle x-ray scattering
Authors: Renner Max , Paesen Guido C. , Grison Claire M. , Granier Sébastien , Grimes Jonathan M. , Leyrat Cédric 
Published: October 2017

AbstractThe phosphoprotein (P) is the main and essential cofactor of the RNA polymerase (L) of non-segmented, negative‐strand RNA viruses. P positions the viral polymerase onto its nucleoprotein–RNA template and acts as a chaperone of the nucleoprotein (N), thereby preventing nonspecific encapsidation of cellular RNAs. The phosphoprotein of human metapneumovirus (HMPV) forms homotetramers composed of a stable oligomerization domain (Pcore) flanked by large intrinsically disordered regions (IDRs). Here we combined x-ray crystallography of Pcore with small angle x-ray scattering (SAXS)-based ensemble modeling of the full-length P protein and several of its fragments to provide a structural description of P that captures its dynamic character, and highlights the presence of varyingly stable structural elements within the IDRs. We discuss the implications of the structural properties of HMPV P for the assembly and functioning of the viral transcription/replication machinery.
Graphene-Like-Graphite as Fast-Chargeable and High-Capacity Anode Materials for Lithium Ion Batteries
Authors: Cheng Qian , Okamoto Yasuharu , Tamura Noriyuki , Tsuji Masayoshi , Maruyama Shunya , Matsuo Yoshiaki 
Published: October 2017

AbstractHere we propose the use of a carbon material called graphene-like-graphite (GLG) as anode material of lithium ion batteries that delivers a high capacity of 608 mAh/g and provides superior rate capability. The morphology and crystal structure of GLG are quite similar to those of graphite, which is currently used as the anode material of lithium ion batteries. Therefore, it is expected to be used in the same manner of conventional graphite materials to fabricate the cells. Based on the data obtained from various spectroscopic techniques, we propose a structural GLG model in which nanopores and pairs of C-O-C units are introduced within the carbon layers stacked with three-dimensional regularity. Three types of highly ionic lithium ions are found in fully charged GLG and stored between its layers. The oxygen atoms introduced within the carbon layers seem to play an important role in accommodating a large amount of lithium ions in GLG. Moreover, the large increase in the interlayer spacing observed for fully charged GLG is ascribed to the migration of oxygen atoms within the carbon layer introduced in the state of C-O-C to the interlayer space maintaining one of the C-O bonds.
TREM-1 promotes intestinal tumorigenesis
Authors: Saurer Leslie , Zysset Daniel , Rihs Silvia , Mager Lukas , Gusberti Matteo , Simillion Cedric , Lugli Alessandro , Zlobec Inti , Krebs Philippe , Mueller Christoph 
Published: October 2017

AbstractTriggering receptor expressed on myeloid cells-1 (TREM-1) is a potent amplifier of pro-inflammatory innate immune responses. Increasing evidence suggests a role for TREM-1 not only in acute pathogen-induced reactions but also in chronic and non-infectious inflammatory disorders, including various types of cancer. Here, we demonstrate that genetic deficiency in Trem1 protects from colorectal cancer. In particular, Trem1−/− mice exhibited reduced tumor numbers and load in an experimental model of inflammation-driven tumorigenesis. Gene expression analysis of Trem1−/− versus Trem1+/+ tumor tissue demonstrated distinct immune signatures. Whereas Trem1−/− tumors showed an increased abundance of transcripts linked to adaptive immunity, Trem1+/+ tumors were characterized by overexpression of innate pro-inflammatory genes associated with tumorigenesis. Compared to adjacent tumor-free colonic mucosa, expression of Trem1 was increased in murine and human colorectal tumors. Unexpectedly, TREM-1 was not detected on tumor-associated Ly6C− MHC class II+ macrophages. In contrast, TREM-1 was highly expressed by tumor-infiltrating neutrophils which represented the predominant myeloid population in Trem1+/+ but not in Trem1−/− tumors. Collectively, our findings demonstrate a clear role of TREM-1 for intestinal tumorigenesis and indicate TREM-1-expressing neutrophils as critical players in colorectal tumor development.
Shape Tailored Magnetic Nanorings for Intracellular Hyperthermia Cancer Therapy
Authors: Dias Carlos S. B. , Hanchuk Talita D. M. , Wender Heberton , Shigeyosi Willian T. , Kobarg Jörg , Rossi André L. , Tanaka Marcelo N. , Cardoso Mateus B. , Garcia Flávio 
Published: October 2017

AbstarctThis work explores a new class of vortex/magnetite/iron oxide nanoparticles designed for magnetic hyperthermia applications. These nanoparticles, named Vortex Iron oxide Particles (VIPs), are an alternative to the traditional Superparamagnetic Iron Oxide Nanoparticles (SPIONs), since VIPs present superior heating power while fulfilling the main requirements for biomedical applications (low cytotoxicity and nonremanent state). In addition, the present work demonstrates that the synthesized VIPs also promote an internalization and aggregation of the particles inside the cell, resulting in a highly localized hyperthermia in the presence of an alternating magnetic field. Thereby, we demonstrate a new and efficient magnetic hyperthermia strategy in which a small, but well localized, concentration of VIPs can promote an intracellular hyperthermia process.
Proteomic Analysis of Thiol Modifications and Assessment of Structural Changes in Hemoglobin Induced by the Aniline Metabolites N-Phenylhydroxylamine and Nitrosobenzene
Authors: Möller Carolina , Davis W. Clay , Thompson Vanessa R. , Marí Frank , DeCaprio Anthony P. 
Published: October 2017

AbstractMS-based proteomic analysis was combined with in silico quantum mechanical calculations to improve understanding of protein adduction by N-phenylhydroxylamine (PhNHOH) and nitrosobenzene (NOB), metabolic products of aniline. In vitro adduction of model peptides containing nucleophilic sidechains (Cys, His, and Lys) and selected proteins (bovine and human hemoglobin and β-lactoglobulin-A) were characterized. Peptide studies identified the Cys thiolate as the most reactive nucleophile for these metabolites, a result consistent with in silico calculations of reactivity parameters. For PhNHOH, sulfinamides were identified as the primary adduction products, which were stable following tryptic digestion. Conversely, reactions with NOB yielded an additional oxidized adduct, the sulfonamide. In vitro exposure of human whole blood to PhNHOH and NOB demonstrated that only sulfinamides were formed. In addition to previously reported adduction of β93Cys of human Hb, two novel sites of adduction were found; α104Cys and β112Cys. We also report CD and UV-Vis spectroscopy studies of adducted human Hb that revealed loss of α-helical content and deoxygenation. The results provide additional understanding of the covalent interaction of aromatic amine metabolites with protein nucleophiles.
A Study of the Brain Functional Network of Post-Stroke Depression in Three Different Lesion Locations
Authors: Shi Yu , Zeng Yanyan , Wu Lei , Liu Ziping , Zhang Shanshan , Yang Jianming , Wu Wen 
Published: October 2017

AbstractResearch on the mechanism of post stroke depression (PSD) is the key way to improve the treatment of PSD. However, the functional brain network of PSD has not been entirely supported by the results of functional magnetic resonance imaging (fMRI) studies. The aims of this study are to investigate the brain response of PSD in three different lesions. The brain responses of the three PSD subgroups were similar. However, each subgroup had its own characteristics of the brain network. In the temporal lobe subgroup, the right thalamus had increased degree centrality (DC) values which were different from the other two subgroups. In the frontal lobe subgroup, the left dorsolateral prefrontal cortex, caudate, and postcentral gyrus had increased DC values which were different from the other two subgroups. The hemodynamic response of PSD indicates that PSD has activities of similar emotional networks, of which the negative network realizes its function through the limbic system and default mode network. The brain network has unique characteristics for different lesion locations. The neurological function of the lesion location, the compensatory mechanism of the brain, and the mechanism of integrity and locality of the brain are the important factors in the individual emotional network.
On the occurrence of intracolonial genotypic variability in highly clonal populations of the hydrocoral Millepora platyphylla at Moorea (French Polynesia)
Authors: Dubé Caroline E. , Planes Serge , Zhou Yuxiang , Berteaux-Lecellier Véronique , Boissin Emilie 
Published: October 2017

AbstractIntracolonial genotypic variability is described in many colonial organisms and arises from mosaicism (somatic mutation) and/or chimerism (allogenic fusion). Both processes provide an additional source of genotypic variation in natural populations and raise questions on the biological significance of colonies having more than one genotype. Using fifteen microsatellite markers, we screened for potential genetic heterogeneity withinMillepora platyphyllacolonies, a hydrocoral species known for its extensive morphological plasticity among reef habitats. We aimed to determine whether mosaicism and chimerism were related to specific reef habitats and/or colony morphologies. Our results show that intracolonial genotypic variability was common (31.4%) inM. platyphyllaat Moorea, French Polynesia, with important variations in its frequency among habitats (0–60%), while no effect of morphology was observed. Mosaicism seemed responsible for most of the genetic heterogeneity (87.5%), while chimerism was rarer. Some mosaics were shared among fire coral clones indicating that mutations could be spread via colony fragmentation. Further, the genotypic variability among clones suggests that colonies produced asexually through fragmentation have the potential to accumulate their own mutations over time. Such mutation dynamics might have important implications for the adaptive potential of long-lived reef-builder populations that are predominantly sustained through asexual reproduction.
Non-noble, efficient catalyst of unsupported α-Cr2O3 nanoparticles for low temperature CO Oxidation
Authors: Bumajdad Ali , Al-Ghareeb Shaimaa , Madkour Metwally , Sagheer Fakhreia Al 
Published: October 2017

AbstractHerein, we report the synthesis of chromium oxide nanoparticles, α -Cr2O3NPs, followed by full characterization via XRD, SEM, XPS, and N2sorptiometry. The synthesized nanoparticles were tested as catalysts toward the oxidation of CO. The impact of calcination temperature on the catalytic activity was also investigated. CO conversion (%), light-off temperature, T50, data were determined. The results revealed that chromia obtained at low calcination temperature (400 °C) is more active than those obtained at high calcination temperatures (600° or 800 °C) and this is ascribed to the smaller particle size and higher surface area of this sample. The results revealed a superior catalytic activity of Cr2O3NPs at lower temperature as we reached a complete conversion at 200 °C which is high value in the forefront of the published results of other non-noble catalysts. The high activity of Cr2O3nanoparticles (T50as low as 98 °C) where found to be dependent on a careful selection of the calcination temperature. These results may provide effective and economic solutions to overcome one of the major environmental threats.
Chemical Stability of Graphene Coated Silver Substrates for Surface-Enhanced Raman Scattering
Authors: Suzuki Seiya , Yoshimura Masamichi 
Published: October 2017

AbstractSurface enhanced Raman spectroscopy (SERS) is a novel method to sense molecular and lattice vibrations at a high sensitivity. Although nanostructured silver surface provides intense SERS signals, the silver surface is unstable under acidic environment and heated environment. Graphene, a single atomic carbon layer, has a prominent stability for chemical agents, and its honeycomb lattice completely prevents the penetration of small molecules. Here, we fabricated a SERS substrate by combining nanostructured silver surface and single-crystal monolayer graphene (G-SERS), and focused on its chemical stability. The G-SERS substrate showed SERS even in concentrated hydrochloric acid (35–37%) and heated air up to 400 °C, which is hardly obtainable by normal silver SERS substrates. The chemically stable G-SERS substrate posesses a practical and feasible application, and its high chemical stability provides a new type of SERS technique such as molecular detections at high temperatures or in extreme acidic conditions.
Bandwidth-enhanced and Wide-angle-of-incidence Metamaterial Absorber using a Hybrid Unit Cell
Authors: Nguyen Toan Trung , Lim Sungjoon 
Published: October 2017

AbstractIn this paper, a bandwidth-enhanced and wide-angle-of-incidence metamaterial absorber is proposed using a hybrid unit cell. Owing to symmetric unit cells, high absorptivity is maintained for all polarization angles. A circular-sector unit cell enables high absorptivity under the oblique incidence of both transverse electric (TE) and transverse magnetic (TM) modes. To enhance the bandwidth, we introduced a hybrid unit cell comprising four circular sectors. Two sectors resonate at 10.38 GHz, and two resonate at 10.55 GHz. Since the two absorption frequencies are near each other, the bandwidth increases. The proposed idea is demonstrated with both full-wave simulations and measurements. The simulated absorptivity exceeds 91% around 10.45 GHz at an angle of incidence up to 70° in both TM and TE polarizations. The measured absorptivity at 10.45 GHz is close to 96.5% for all polarization angles under normal incidence. As the angle of incidence changes from 0° to 70°, the measured absorptivity at 10.45 GHz remains above 90% in the TE mode and higher than 94% in the TM mode. Under an oblique incidence, the measured 90% absorption bandwidth is 1.95% from 10.1–10.2 GHz and 10.4–10.5 GHz up to 70° at the TE mode, and 3.39% from 10.15–10.5 GHz up to 70° at the TM mode.
Asymmetric BMP4 signalling improves the realism of kidney organoids
Authors: Mills Christopher G. , Lawrence Melanie L. , Munro David A. D. , Elhendawi Mona , Mullins John J. , Davies Jamie A. 
Published: October 2017

AbstractWe present a strategy for increasing the anatomical realism of organoids by applying asymmetric cues to mimic spatial information that is present in natural embryonic development, and demonstrate it using mouse kidney organoids. Existing methods for making kidney organoids in mice yield developing nephrons arranged around a symmetrical collecting duct tree that has no ureter. We use transplant experiments to demonstrate plasticity in the fate choice between collecting duct and ureter, and show that an environment rich in BMP4 promotes differentiation of early collecting ducts into uroplakin-positive, unbranched, ureter-like epithelial tubules. Further, we show that application of BMP4-releasing beads in one place in an organoid can break the symmetry of the system, causing a nearby collecting duct to develop into a uroplakin-positive, broad, unbranched, ureter-like ‘trunk’ from one end of which true collecting duct branches radiate and induce nephron development in an arrangement similar to natural kidneys. The idea of using local symmetry-breaking cues to improve the realism of organoids may have applications to organoid systems other than the kidney.