bluuebunny/crossref_metadata_2025_split huggingface dataset:
Samarium(II) Monoalkyl Complex Supported by a β‐Diketiminato‐Based Tetradentate Ligand: Synthesis, Structure, and Catalytic Hydrosilylation of Internal Alkynes
Authors: Liu Xiaojuan , Wen Qingqing , Xiang Li , Leng Xuebing , Chen Yaofeng 
Published: March 2020

AbstractThe synthesis and catalytic applications of trivalent rare‐earth metal alkyl complexes have been well developed, but the chemistry of divalent rare‐earth metal alkyl complexes lagged much behind. Herein, we report the synthesis, structure, and catalytic applications of a samarium(II) monoalkyl complex supported by a β‐diketiminato‐based tetradentate ligand, [LSmCH(SiMe3)2] (L=[MeC(NDipp)CHC(Me)NCH2CH2N(Me)CH2CH2NMe2]−, Dipp=2,6‐(iPr)2C6H3). This complex is synthesized by the salt metathesis reaction of samarium iodide [LSm(μ‐I)]2 and KCH(SiMe3)2 in 63 % yield. Its structure is characterized by single‐crystal X‐ray diffraction, showing a distorted square‐pyramid coordination geometry. This samarium(II) monoalkyl complex exhibits high catalytic activity in the hydrosilylation of aryl and methyl‐substituted unsymmetrical internal alkynes with secondary hydrosilanes, selectively providing the α‐(E) products in high yields.
Enzymatic Syntheses and Applications of Fluorescent Cyclic Dinucleotides
Authors: Li Yao , Ludford Paul T. , Fin Andrea , Rovira Alexander R. , Tor Yitzhak 
Published: March 2020

AbstractBacterial cyclic dinucleotides (CDNs) play important roles in regulating biofilm formation, motility and virulence. In eukaryotic cells, theses bacterial CDNs are recognized as pathogen‐associated molecular patterns (PAMPs) and trigger an innate immune response. We report the photophysical analyses of a novel group of enzymatically synthesized emissive CDN analogues comprised of two families of isomorphic ribonucleotides. The highly favorable photophysical features of the CDN analogues, when compared to their non‐emissive natural counterparts, are used to monitor in real time the dinucleotide cyclase‐mediated synthesis and phosphodiesterase (PDE)‐mediated hydrolysis of homodimeric and mixed CDNs, providing effective means to probe the activities of two classes of bacterial enzymes and insight into their biomolecular recognition and catalytic features.
Organocatalytic Multicomponent Synthesis of α/β‐Dipeptide Derivatives
Authors: Martzel Thomas , Annibaletto Julien , Millet Pierre , Pair Etienne , Sanselme Morgane , Oudeyer Sylvain , Levacher Vincent , Brière Jean‐François 
Published: March 2020

AbstractA straightforward multicomponent Knoevenagel‐aza‐Michael‐cyclocondensation reaction involving readily available hydroxamic acid‐derived from naturally occurring α‐amino acids allows a diversity‐oriented synthesis of novel isoxazolidin‐5‐ones possessing an N‐protected α‐amino acid pendant with good to high diastereoselectivities thanks to a match effect with a chiral organocatalyst. These diversely substituted heterocycles, easily isolated as a single diastereoisomer, proved to be versatile platforms for the formation of an array of α/β‐dipeptide fragments.
Fabrication of Silica/Sulfur@Polyaniline Spheres with Radial Mesochannels as Enhanced Cathode Materials for High‐Performance Lithium−Sulfur Batteries
Authors: Gong Qinghua , Gu Shaonan , Li Jifan , Wang Qian , Sun Xuefeng , Zhou Guowei 
Published: March 2020

AbstractThe unique structure SiO2/S@polyaniline (PANI) composite with radial meso‐channels was designed and synthesized by in situ chemical oxidative polymerization of aniline on SiO2/S surface. The composite was used as the cathode for lithium−sulfur batteries. The SiO2 nanospheres with radial meso‐channels provided sufficient internal space to accommodate the volume expansion for sulfur and possessed strong adsorption capability for lithium polysulfides (LiPSs). Additionally, the thin PANI coating serving as conductive frameworks generated sufficient electrical conduction paths and effectively prevented the outward diffusion of LiPSs, leading to long‐term stability. Benefitting from the composites’ unique structural and compositional advantages, we obtained an initial specific capacity of 1008.6 mA h g−1 at 0.2 C and an outstanding cycling stability at 1 C rate over 1000 cycles with a capacity decay of 0.04% per cycle. An excellent rate performance of 630.2 mA h g−1 at 2 C was also achieved. Our work reveals the potential application of the porous SiO2@PANI‐based sulfur cathodes in future high‐performance lithium−sulfur batteries. Furthermore, first‐principle calculations and X‐ray photoelectron spectroscopy analysis prove the strong adsorption of LiPSs by the SiO2 surface. The formation of S−O bond on the SiO2 is also found to dominate the adsorption mechanism between LiPSs and SiO2.
Simple Protocol for Generating and Genotyping Genome‐Edited Mice With CRISPR‐Cas9 Reagents
Authors: Fernández Almudena , Morín Matías , Muñoz‐Santos Diego , Josa Santiago , Montero Andrea , Rubio‐Fernández Marcos , Cantero Marta , Fernández Julia , del Hierro María Jesús , Castrillo Marta , Moreno‐Pelayo Miguel Ángel , Montoliu Lluís 
Published: March 2020

AbstractThe simple protocol described in this article aims to provide all required information, as a comprehensive, easy‐to‐follow step‐by‐step method, to ensure the generation of the expected genome‐edited mice. Here, we provide protocols for the preparation of CRISPR‐Cas9 reagents for microinjection and electroporation into one‐cell mouse embryos to create knockout or knock‐in mouse models, and for genotyping the resulting offspring with the latest innovative next‐generation sequencing methods. © 2020 by John Wiley & Sons, Inc.Basic Protocol 1: Designing the best RNA guide for your gene disruption/editing strategyBasic Protocol 2: Preparing and validating CRISPR‐Cas9 reagentsBasic Protocol 3: Preparing and injecting CRISPR‐Cas9 compounds into fertilized mouse oocytesBasic Protocol 4: Genotyping genome‐edited miceSupport Protocol: Genotyping for CRISPR‐generated “indel” mutations
Laser‐generated ns plasma pulses characterized using SiC Schottky diode
Authors: Torrisi Lorenzo , Torrisi Alfio , Cutroneo Mariapompea 
Published: March 2020

AbstractThe nonequilibrium plasma generated by nanosecond laser pulse is characterized using a SiC detector connected in time‐of‐flight configuration to measure the radiations emitted from the plasma. Different metallic targets were irradiated by the pulsed laser at an intensity of 1010 W/cm2 and 200 mJ pulse energy. The SiC allows detecting ultraviolet radiations and soft X‐rays, electrons, and ions. The obtained plasma has a temperature of the order of tens to hundreds eV depending on the atomic number of the irradiated target and ion accelerations of the order of 100 eV per charge state.
Geomorphology and climate interact to control organic carbon stock and age in mountain river valley bottoms
Authors: Scott Daniel N. , Wohl Ellen 
Published: March 2020

AbstractOrganic carbon (OC) in valley bottom downed wood and soil that cycles over short to moderate timescales (101 to 105 years) represents a large, dynamic, and poorly quantified pool of carbon whose distribution and residence time affects global climate. We sought to quantify this potentially important OC pool at the watershed scale to estimate its magnitude and age, as well as determine the controls on its variability within watersheds. To do this, we compared four disparate mountain river basins to show that mountain river valley bottoms store substantial estimated OC stocks in floodplain soil and downed wood (median OC of
MgC/ha, n = 178). Although soil OC is generally young (exhibiting a median radiocarbon fraction modern value of
, n = 121), geomorphic processes regulate soil burial and processes that limit microbial respiration, preserving aged OC in especially deep, unconfined, wet, and/or high‐elevation floodplain soils. We statistically modeled OC stocks to show that valley bottom morphology and hydrology regulate variability in floodplain soil retention and resulting variability in OC stock and age in floodplain soil throughout river networks. Comparing the distribution of OC stocks between wood and soil, we find that where floodplain soils are present, their OC stocks are generally greater than OC stocks stored in wood. Our results suggest that although mountain rivers may accumulate large OC stocks relatively rapidly, those stocks are highly sensitive to alterations in soil and wood retention, implying that human alterations to either disturb or restore floodplain wood and soil storage may have substantial impacts on OC storage in river corridors. © 2020 John Wiley & Sons, Ltd.
Estimation of Nusselt number and effectiveness of double‐pipe heat exchanger with Al2O3–, CuO–, TiO2–, and ZnO–water based nanofluids
Authors: Pattanayak Bikash , Mund Abhishek , Jayakumar J. S. , Parashar Kajal , Parashar Sujay K. S. 
Published: March 2020

AbstractThis paper deals with experimental studies carried out to analyze heat transfer characteristics of Al2O3–, CuO–, TiO2–, and ZnO–water based nanofluids in a double‐pipe, counter flow heat exchanger for different volume concentrations (0.025%, 0.05%, 0.075%, and 0.1%) of the nanofluids. The fabricated double‐pipe heat exchanger is made up of two different materials, viz., copper as the inner tube and unplasticized polyvinyl chloride as the outer tube. The density, viscosity, and thermal conductivity were calculated, and were used to estimate dimensionless numbers, such as Reynolds number, Prandtl number, and Nusselt number, and also to estimate heat exchanger effectiveness. High‐energy ball milling technique was used to prepare nanoparticles and were characterized using X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. Polyvinyl alcohol (3%) was used as a surfactant for making the nanofluids stable. It was observed from the experiment that with the increase in the volume concentration, thermal conductivity, viscosity, and friction factor increase, whereas the Reynolds number decreases. The experimentally observed data for Nusselt number were formulated into a correlation that matches the data for all these nanofluids within an error of 11.4%. It was found that the highest effectiveness was obtained while using TiO2–water nanofluids than other nanofluids.
Soret and Dufour effects on MHD flow of viscoelastic fluid past an infinite vertical stretching sheet
Authors: Siva Kumar Reddy B. , Surya Narayana Rao K. V. , Vijaya R. Bhuvana 
Published: March 2020

AbstractHeat and mass transmission taking place in a magnetohydrodynamics fluid of substantial viscosity via a permeable object has been currently a subject of study inviting research. This transmission takes place along an infinite expanding vertical surface showing Soret and Dufour effects. Differential forms of nonlinear nature such as energy, momentum, and equations defining concentration are ascertained by means of similarity transformation with the existing buoyancy force, and by making use of the homotopy analysis method, the equations have been analytically resolved. The impacts arising out of applied factors on temperature, velocity, and concentration forms have been appropriately designed and established.
Contrast‐Enhanced MRI Combined With the Glycerol Test Reveals the Heterogeneous Dynamics of Endolymphatic Hydrops in Patients With Menière's Disease
Authors: Wang Pengjun , Yu Dongzhen , Wang Hui , Ye Haibo , Qiao Ruihua , Chen Zhengnong , Wu Yaqin , Li Yuehua , Shi Haibo , Zou Jing , Yin Shankai 
Published: March 2020

BackgroundThe sensitivity of endolymphatic hydrops (EH) to the glycerol test varies in patients with Menière's disease (MD).PurposeTo explore the features of EH and its glycerol‐induced dynamics in MD.Study TypeCase–control study.PopulationTwenty patients with MD (24 affected ears) were included.Field Strength/Sequence3.0T 3D‐FLAIR (fluid‐attenuated inversion recovery) MRI and late gadolinium enhancement.AssessmentIntratympanic gadolinium‐enhanced MRI was performed in the MD‐affected ears before and after the glycerol test. The borders of the endolymphatic and total lymphatic space were contoured on the axial MRI slices to evaluate the volume of hydrops in both the cochlear and vestibular regions.Statistical TestsPaired and unpaired t‐tests, the Mann–Whitney U‐test, linear discriminant analysis, Pearson's correlation, and linear regression.ResultsAfter glycerol ingestion, vestibular EH decreased in all patients, whereas cochlear EH significantly decreased only in patients with positive glycerol test results (all P < 0.01). At baseline, cochlear EH in the positive result group was greater than in the negative result group (P = 0.007). Unexpectedly, in the positive result group a drastic glycerol‐induced dehydrating effect was observed in patients whose pretest cochlear EH ratio was >16% (P = 0.011). Moreover, the dehydrating role of glycerol was positively correlated with the baseline cochlear hydrops level (r = 0.7691, P < 0.001).Data ConclusionMRI provides evidence that glycerol administration improves the hearing threshold via dehydrating the EH. In the cochlear region, the baseline level of cochlear EH is a closely related factor for the validity of the glycerol test, whereas EH is consistently dehydrated in the vestibular component.Level of Evidence2Technical Efficacy Stage3 J. Magn. Reson. Imaging 2020;52:1066–1073.
Antigenic drift of hemagglutinin and neuraminidase in seasonal H1N1 influenza viruses from Saudi Arabia in 2014 to 2015
Authors: Naeem Asif , Elbakkouri Karim , Alfaiz Ali , Hamed Maaweya E. , Alsaran Hadel , AlOtaiby Shahad , Enani Mushira , Alosaimi Bandar 
Published: March 2020

AbstractAntigenic drift of the hemagglutinin (HA) and neuraminidase (NA) proteins of the influenza virus cause a decrease in vaccine efficacy. Since the information about the evolution of these viruses in Saudi is deficient so we investigated the genetic diversity of circulating H1N1 viruses. Nasopharyngeal aspirates/swabs collected from 149 patients hospitalized with flu‐like symptoms during 2014 and 2015 were analyzed. Viral RNA extraction was followed by a reverse transcription‐polymerase chain reaction and genetic sequencing. We analyzed complete gene sequences of HA and NA from 80 positive isolates. Phylogenetic analysis of HA and NA genes of 80 isolates showed similar topologies and co‐circulation of clades 6b. Genetic diversity was observed among circulating viruses belonging to clade 6B.1A. The amino acid residues in the HA epitope domain were under purifying selection. Amino acid changes at key antigenic sites, such as position S101N, S179N (antigenic site‐Sa), I233T (antigenic site‐Sb) in the head domain might have resulted in antigenic drift and emergence of variant viruses. For NA protein, 36% isolates showed the presence of amino acid changes such as V13I (n = 29), I314M (n = 29) and 12% had I34V (n = 10). However, H257Y mutation responsible for resistance to neuraminidase inhibitors was missing. The presence of amino acid changes at key antigenic sites and their topologies with structural mapping of residues under purifying selection highlights the importance of antigenic drift and warrants further characterization of recently circulating viruses in view of vaccine effectiveness. The co‐circulation of several clades and the predominance of clade 6B.1 suggest multiple introductions in Saudi.
Computation of quantum‐corrected noise in graphene‐SiC‐based impact avalanche transit time diode
Authors: Ghivela Girish C. , Sengupta Joydeep 
Published: March 2020

AbstractHere, we have performed the noise analysis in graphene‐SiC‐based double drift region impact avalanche transit time diode (IMPATT). For computation, the noise model taken is based on drift diffusion with quantum corrections. Though noise computation in IMPATT with classical drift diffusion model are widely followed in earlier years, noise analysis through classical drift diffusion model is independent of confinement and tunneling due to quantum effects. Noise computed through quantum‐corrected noise model is more accurate to measured noise. Therefore, by considering quantum effects in addition to classical noise model, we have computed the noise in graphene‐SiC IMPATT. The noise performance of graphene‐SiC IMPATT is evaluated at Ka band which ranges from 26.5 to 40 GHz. The obtained noise from graphene‐SiC IMPATT is in good agreement with earlier reported noise behavior in IMPATT. We observed that the graphene‐SiC IMPATT is giving the better noise performance in terms of lower computed noise and noise spectral density as compared to other materials reported so far.
Optical Imaging of Coherent Molecular Rotors
Authors: Bert Jérémy , Prost Emilien , Tutunnikov Ilia , Béjot Pierre , Hertz Edouard , Billard Franck , Lavorel Bruno , Steinitz Uri , Averbukh Ilya Sh. , Faucher Olivier 
Published: March 2020

AbstractShort laser pulses are widely used for controlling molecular rotational degrees of freedom and inducing molecular alignment, orientation, unidirectional rotation, and other types of coherent rotational motion. To follow the ultrafast rotational dynamics in real time, several techniques for producing molecular movies have been proposed based on the Coulomb explosion of rotating molecules, or recovering molecular orientation from the angular distribution of high harmonics. The present work offers and demonstrates a novel nondestructive optical method for direct visualization and recording of movies of coherent rotational dynamics in a molecular gas. The technique is based on imaging the time‐dependent polarization dynamics of a probe light propagating through a gas of coherently rotating molecules. The probe pulse continues through a radial polarizer, and is then recorded by a camera. The technique is illustrated by implementing it with two examples of time‐resolved rotational dynamics: alignment–antialignment cycles in a molecular gas excited by a single linearly polarized laser pulse, and unidirectional molecular rotation induced by a pulse with twisted polarization. This method may open new avenues in studies on fast chemical transformation phenomena and ultrafast molecular dynamics caused by strong laser fields of various complexities.
Gut microbial diversity and stabilizing functions enhance the plateau adaptability of Tibetan wild ass (Equus kiang)
Authors: Gao Hongmei , Chi Xiangwen , Li Guangying , Qin Wen , Song Pengfei , Jiang Feng , Liu Daoxin , Zhang Jingjie , Zhou Xiaowen , Li Shengqing , Zhang Tongzuo 
Published: March 2020

AbstractInteractions between gut microbiota not only regulate physical health, but also form a vital bridge between the environment and the host, thus helping the host to better adapt to the environment. The improvement of modern molecular sequencing techniques enables in‐depth investigations of the gut microbiota of vertebrate herbivores without harming them. By sequencing the 16S rRNA V4‐V5 region of the gut microbiota of both the captive and wild kiang in winter and summer, the diversity and function of the microbiota could be compared. The reasons for observed differences were discussed. The results showed that the dominant phyla of the kiang were Bacteroidetes and Firmicutes, and the structure and abundance of the gut microbiota differed significantly between seasons and environments. However, the relatively stable function of the gut microbiota supplies the host with increased adaptability to the environment. The diversity of the intestinal flora of the kiang is relatively low in captivity, which increases their risk to catch diseases to some extent. Therefore, importance should be attached to the impact of captivity on wildlife.
XB130, regulated by miR‐203, miR‐219, and miR‐4782‐3p, mediates the proliferation and metastasis of non‐small‐cell lung cancer cells
Authors: Wang Qinrong , Yang Guohui , Jiang Yinhui , Luo Mei , Li Chao , Zhao Yan , Xie Yuan , Song Kewei , Zhou Jianjiang 
Published: March 2020

AbstractXB130 is a novel adapter protein that behaves as a tumor promoter or suppressor mediating cell proliferation and metastasis in the development of different human tumors. Altered expression of XB130 has been verified in human non‐small cell‐lung cancer (NSCLC). However, the exact effect of XB130 on NSCLC is not well‐understood. In this study, we investigated the biological function and posttranscriptional regulation of XB130 in NSCLC. First, the effects of XB130 silence on NSCLC cell proliferation, migration, invasion, and epithelial‐mesenchymal transition (EMT) were examined. Then the targeting relationship between XB130 and miR‐203, miR‐219, or miR‐4782‐3p was demonstrated by dual‐luciferase reporter assay. Finally, the effects of miR‐203, miR‐219, and miR‐4782‐3p on NSCLC cell function were studied, respectively. We found that XB130 silence significantly inhibited cell growth, migration and invasion, and reversed EMT. Furthermore, XB130 was posttranscriptionally regulated by miR‐203, miR‐219, and miR‐4782‐3p. Overexpression of miR‐203, miR‐219, or miR‐4782‐3p inhibited cell growth, migration and invasion, and reversed EMT, just like the role of XB130 in NSCLC cells, whereas the suppressive effects of microRNA (miRNA) overexpression were weakened by miRNA inhibitors or ectopic expression of XB130 in NSCLC cells. These data demonstrate that XB130 is posttranscriptionally regulated by miR‐203, miR‐219, and miR‐4782‐3p and mediates the proliferation and metastasis of NSCLC cells.
Reliable and accurate needle localization in curvilinear ultrasound images using signature‐based analysis of ultrasound beamformed radio frequency signals
Authors: Daoud Mohammad I. , Abu‐Hani Ayah F. , Alazrai Rami 
Published: March 2020

PurposeUltrasound imaging is used in many minimally invasive needle insertion procedures to track the advancing needle, but localizing the needle in ultrasound images can be challenging, particularly at steep insertion angles. Previous methods have been introduced to localize the needle in ultrasound images, but the majority of these methods are based on ultrasound B‐mode image analysis that is affected by the needle visibility. To address this limitation, we propose a two‐phase, signature‐based method to achieve reliable and accurate needle localization in curvilinear ultrasound images based on the beamformed radio frequency (RF) signals that are acquired using conventional ultrasound imaging systems.MethodsIn the first phase of our proposed method, the beamformed RF signals are divided into overlapping segments and these segments are processed to extract needle‐specific features to identify the needle echoes. The features are analyzed using a support vector machine classifier to synthesize a quantitative image that highlights the needle. The quantitative image is processed using the Radon transform to achieve a reliable and accurate signature‐based estimation of the needle axis. In the second phase, the accuracy of the needle axis estimation is improved by processing the RF samples located around the signature‐based estimation of the needle axis using local phase analysis combined with the Radon transform. Moreover, a probabilistic approach is employed to identify the needle tip. The proposed method is used to localize needles with two different sizes inserted in ex vivo animal tissue specimens at various insertion angles.ResultsOur proposed method achieved reliable and accurate needle localization for an extended range of needle insertion angles with failure rates of 0% and mean angle, axis, and tip errors smaller than or equal to

, 0.6 mm, and 0.7 mm, respectively. Moreover, our proposed method outperformed a recently introduced needle localization method that is based on B‐mode image analysis.ConclusionsThese results suggest the potential of employing our signature‐based method to achieve reliable and accurate needle localization during ultrasound‐guided needle insertion procedures.