bluuebunny/crossref_metadata_2025_split huggingface dataset:
Joint Elastic‐Electrical Properties of Artificial Porous Sandstone With Aligned Fractures
Authors: Han Tongcheng 
Published: March 2018

AbstractSeismic and electromagnetic surveys are among the most important geophysical applications to understand the subsurface Earth. Joint interpretation of the independent but complementary exploration data can provide geophysical parameters needed to better assess the rocks. However, cross‐property relationship between the elastic and electrical properties of fractured porous rocks, the key to the successful joint interpretation of seismic and electromagnetic data in anisotropic formations, is poorly understood. Here we use dedicated laboratory experiments and theoretical modeling to show how elastic velocity and electrical conductivity are linked in porous sandstone with aligned fractures and how the joint properties are affected by the fractures. The P and SH wave velocities are found to be approximately linearly correlated with electrical conductivity when measured in varying directions, and the linear trends are determined by the geometry and amount of the fractures in the rocks. The results provide a pathway to successful joint interpretation in fractured rocks.
Global Distribution and Spectral Properties of Low‐Reflectance Material on Mercury
Authors: Klima Rachel L. , Denevi Brett W. , Ernst Carolyn M. , Murchie Scott L. , Peplowski Patrick N. 
Published: March 2018

AbstractWe examine the global distribution and spectral properties of low‐reflectance material (LRM) across Mercury to estimate the relative carbon abundance of prominent exposures and to test hypotheses for the origin of carbon in LRM. Our mapping demonstrates that LRM is consistently excavated from depth and that the spectral curvature attributed to carbon becomes more subdued as these surface deposits age. We find that the 600‐nm band depth in LRM deposits is related to carbon content and can be used to estimate carbon enrichment. LRM deposits excavated by basins and large craters may be enriched with as much as 4 wt% carbon over the local mean. Regional deposits, associated with the most heavily cratered terrains, are enriched by an average of ~2.5 wt% carbon. The association of LRM with excavation from depth shows that the carbon in LRM is native to the planet, rather than deposited over time by impacts.
Crustal Deformation across the Jericho Valley Section of the Dead Sea Fault as Resolved by Detailed Field and Geodetic Observations
Authors: Hamiel Yariv , Piatibratova Oksana , Mizrahi Yaakov , Nahmias Yoav , Sagy Amir 
Published: March 2018

AbstractDetailed field and geodetic observations of crustal deformation across the Jericho Fault section of the Dead Sea Fault are presented. New field observations reveal several slip episodes that rupture the surface, consist with strike slip and extensional deformation along a fault zone width of about 200 m. Using dense Global Positioning System measurements, we obtain the velocities of new stations across the fault. We find that this section is locked for strike‐slip motion with a locking depth of 16.6 ± 7.8 km and a slip rate of 4.8 ± 0.7 mm/year. The Global Positioning System measurements also indicate asymmetrical extension at shallow depths of the Jericho Fault section, between 0.3 and 3 km. Finally, our results suggest the vast majority of the sinistral slip along the Dead Sea Fault in southern Jorden Valley is accommodated by the Jericho Fault section.
Lightning Mapping With an Array of Fast Antennas
Authors: Wu Ting , Wang Daohong , Takagi Nobuyuki 
Published: March 2018

AbstractFast Antenna Lightning Mapping Array (FALMA), a low‐frequency lightning mapping system comprising an array of fast antennas, was developed and established in Gifu, Japan, during the summer of 2017. Location results of two hybrid flashes and a cloud‐to‐ground flash comprising 11 return strokes (RSs) are described in detail in this paper. Results show that concurrent branches of stepped leaders can be readily resolved, and K changes and dart leaders with speeds up to 2.4 × 107 m/s are also well imaged. These results demonstrate that FALMA can reconstruct three‐dimensional structures of lightning flashes with great details. Location accuracy of FALMA is estimated by comparing the located striking points of successive RSs in cloud‐to‐ground flashes. Results show that distances between successive RSs are mainly below 25 m, indicating exceptionally high location accuracy of FALMA.
High‐Performance n‐ and p‐Type Field‐Effect Transistors Based on Hybridly Surface‐Passivated Colloidal PbS Nanosheets
Authors: Ramin Moayed Mohammad Mehdi , Bielewicz Thomas , Noei Heshmat , Stierle Andreas , Klinke Christian 
Published: March 2018

AbstractColloidally synthesized nanomaterials are among the promising candidates for future electronic devices due to their simplicity and the inexpensiveness of their production. Specifically, colloidal nanosheets are of great interest since they are conveniently producible through the colloidal approach while having the advantages of two‐dimensionality. In order to employ these materials, according transistor behavior should be adjustable and of high performance. It is shown that the transistor performance of colloidal lead sulfide nanosheets is tunable by altering the surface passivation, the contact metal, or by exposing them to air. It is found that adding halide ions to the synthesis leads to an improvement of the conductivity, the field‐effect mobility, and the on/off ratio of these transistors by passivating their surface defects. Superior n‐type behavior with a field‐effect mobility of 248 cm2 V−1 s−1 and an on/off ratio of 4 × 106 is achieved. The conductivity of these stripes can be changed from n‐type to p‐type by altering the contact metal and by adding oxygen to the working environment. As a possible solution for the post‐Moore era, realizing new high‐quality semiconductors such as colloidal materials is crucial. In this respect, the results can provide new insights which helps to accelerate their optimization for potential applications.
Cavitation Mediated 3D Microstructured Architectures from Nanocarbon
Authors: Zhang Zishuai , Ye Siyu , Gbureck Uwe , Barralet Jake E. , Merle Géraldine 
Published: March 2018

AbstractHere, the formation of high surface area microscale assemblies of nanocarbon through phosphate and ultrasound cavitation treatment is reported. Despite high conductivity and large surface area, potential health and safety concerns limit the use of nanocarbon and add challenges to handling. Previously, it is shown that phosphate ultrasonic bonding is ineffective for organic materials but in this study, it is found that by a preliminary oxidizing treatment, several carbons can be readily assembled from xerogels. Assembling nanocarbon into microparticles can usually require a binder or surfactants, which can reduce surface area or conductivity and generate a low microsphere yield. Carbon nanotube microspheres are nitrogen‐doped and flower‐like nanostructured Pt deposited on their surface, and finally showcased as efficient cathode electrocatalysts for the oxygen reduction reaction (half‐wave potential 0.78 V vs reversible hydrogen electrode) and methanol oxidation (417 mA mg−1). In particular, no significant degradation of the catalysts is detected after 12 000 cycles (26.6 h). These results indicate the potential of this multimaterial assembly method and open a new way to improve handling of nanoscale materials.
Role of Localized States in Photoluminescence Dynamics of High Optical Gain CsPbBr3 Nanocrystals
Authors: Dey Amrita , Rathod Pravin , Kabra Dinesh 
Published: March 2018

AbstractTemperature‐dependent time‐resolved photoluminescence (TRPL) spectroscopy of high optical gain CsPbBr3 nanocrystals (NCs) films along with temperature‐dependent steady‐state absorption and photoluminescence (PL) spectra is studied. A red shift in the optical band edge and the corresponding PL peak is observed by lowering the temperature from room temperature, analogous to hybrid perovskite semiconductors. However, the faster PL decay of CsPbBr3 NCs film at a low temperature as compared to room temperature is in contrast with many other traditional colloidal quantum dots. The TRPL spectroscopy as a function of temperature suggests the presence of a red‐shifted (≈75 ± 15 meV) defect‐induced emission peak at longer times. Temperature‐dependent PL intensity study shows an Arrhenius type of character with two activation energies: ≈77 ± 18 and ≈12 ± 3 meV. A qualitative model is developed where interaction between the excitonic level and these observed localized states as a function of temperature can qualitatively explain the contrasting PL decay mechanism of CsPbBr3 NCs film. To ensure the quality of in‐house synthesized CsPbBr3 NCs with a mixture of oleylamine and octylamine ligands, the amplified spontaneous emission from CsPbBr3 NCs film as a planar waveguide medium is studied, which shows state‐of‐art optical gain coefficient of ≈51cm−1 and a loss coefficient of ≈15cm−1 at room temperature.
Catalytic Asymmetric Synthesis of All Possible Stereoisomers of 2,3,4,6‐Tetradeoxy‐4‐Aminohexopyranosides
Authors: Zhu Zhongpeng , Glazier Daniel A. , Yang Daoshan , Tang Weiping 
Published: March 2018

AbstractWe recently developed a divergent strategy for the synthesis of all eight possible 2,3,6‐trideoxyhexopyranosides with three stereogenic centers. However, the diastereoselectivity for one of the three stereogenic centers was low and it was not controlled by catalysts. In this update, we described a systematic method for the first catalytic asymmetric synthesis of all eight possible 2,3,6‐trideoxyhexopyranosides and all eight possible 2,3,4,6‐tetradeoxy‐4‐aminohexopyranosides. The products derived from this strategy include the glycone of natural products grecocycline A, spinosyn A, and ossamycin. All three stereogenic centers in each product was controlled by a pair of chiral catalysts. The key to the success is the application of our recently developed dynamic kinetic stereodivergent acylation of Achmatowicz rearrangement products and chiral catalyst‐directed reduction. Simple dimethylation of the 2,3,4,6‐tetradeoxy‐4‐amino sugars afforded derivatives of naturally occurring β‐D‐forosaminide and β‐L‐ossaminide.magnified image
Painful Terminal Neuroma Prevention by Capping PRGD/PDLLA Conduit in Rat Sciatic Nerves
Authors: Yi Jiling , Jiang Nan , Li Binbin , Yan Qiongjiao , Qiu Tong , Swaminatha Iyer Killugudi , Yin Yixia , Dai Honglian , Yetisen Ali K. , Li Shipu 
Published: March 2018

AbstractNeuroma formation after amputation as a long‐term deficiency leads to spontaneous neuropathic pain that reduces quality of life of patients. To prevent neuroma formation, capping techniques are implemented as effective treatments. However, an ideal, biocompatible material covering the nerves is an unmet clinical need. In this study, biocompatible characteristics presented by the poly(D,L‐lactic acid)/arginylglycylaspartic acid (RGD peptide) modification of poly{(lactic acid)‐co‐ [(glycolic acid)‐alt‐(L‐lysine)]} (PRGD/PDLLA) are evaluated as a nerve conduit. After being capped on the rat sciatic nerve stump in vivo, rodent behaviors and tissue structures are compared via autotomy scoring and histological analyses. The PRGD/PDLLA capped group gains lower autotomy score and improves the recovery, where inflammatory infiltrations and excessive collagen deposition are defeated. Transmission electron microscopy images of the regeneration of myelin sheath in both groups show that abnormal myelination is only present in the uncapped rats. Changes in related genes (MPZ, MBP, MAG, and Krox20) are monitored quantitative real‐time polymerase chain reaction (qRT‐PCR) for mechanism investigation. The PRGD/PDLLA capping conduits not only act as physical barriers to inhibit the invasion of inflammatory infiltration in the scar tissue but also provide a suitable microenvironment for promoting nerve repairing and avoiding neuroma formation during nerve recovery.
From Checkerboard‐Like Sand Barriers to 3D Cu@CNF Composite Current Collectors for High‐Performance Batteries
Authors: Luo Jian , Yuan Wei , Huang Shimin , Zhao Bote , Chen Yu , Liu Meilin , Tang Yong 
Published: March 2018

AbstractWhile the architecture, surface morphology, and electrical conductivity of current collectors may significantly affect the performance of electrochemical cells, many challenges still remain in design and cost‐effective fabrication of highly efficient current collectors for a new generation of energy storage and conversion devices. Here the findings in design and fabrication of a 3D checkerboard‐like Cu@CNF composite current collector for lithium‐ion batteries are reported. The surface of the current collector is modified with patterned grooves and amorphous carbon nanofibers, imitating the checkerboard‐like sand barriers in desert regions. Due to a combined effect of the grooves and the carbon nanofibers, a battery based on this current collector retains a reversible capacity of 410.1 mAh g−1 (beyond the theoretical capacity of carbonaceous materials of 372 mAh g−1) with good capacity retention (greater than 84.9% of the initial capacity after 50 cycles), resulting in 66.2% and 42.6% improvement in reversible capacity and capacity retention, respectively, compared to the batteries using traditional Cu current collectors. Based on the excellent electrochemical performance, this composite current collector is believed to be an attractive alternative to the traditional commercially used current collectors for the anode of high‐power energy storage systems.
Perceptions of Housing and Shelter among People with Histories of Unstable Housing in three Cities in Canada: A Qualitative Study
Authors: Sylvestre John , Klodawsky Fran , Gogosis Evie , Ecker John , Polillo Alexia , Czechowski Konrad , Agha Ayda , Shankar Sneha , To Matthew , Gadermann Anne , Palepu Anita , Hwang Stephen 
Published: March 2018

AbstractHousing is a key social determinant of health that contributes to the well‐documented relationship between socioeconomic status and health. This study explored how individuals with histories of unstable and precarious housing perceive their housing or shelter situations, and the impact of these settings on their health and well‐being. Participants were recruited from the Health and Housing in Transition study (HHiT), a longitudinal, multi‐city study that tracked the health and housing status of people with unstable housing histories over a 5‐year period. For the current study, one‐time semi‐structured interviews were conducted with a subset of HHiT study participants (n = 64), living in three cities across Canada: Ottawa, Toronto, and Vancouver. The findings from an analysis of the interview transcripts suggested that for many individuals changes in housing status are not associated with significant changes in health due to the poor quality and precarious nature of the housing that was obtained. Whether housed or living in shelters, participants continued to face barriers of poverty, social marginalization, inadequate and unaffordable housing, violence, and lack of access to services to meet their personal needs.
Cobalt(II)/N,N′,N′′‐Trihydroxyisocyanuric Acid Catalyzed Aerobic Oxidative Esterification and Amidation of Aldehydes
Authors: Jiang Biao‐Lin , Xu Bao‐Hua , Wang Meng‐Liang , Li Zeng‐Xi , Liu Dian‐Sheng , Zhang Suo‐Jiang 
Published: March 2018

AbstractA protocol for a CoII/N,N′,N′′‐trihydroxyisocyanuric acid (THICA)‐catalyzed aerobic oxidative esterification and amidation of aldehydes has been developed. Preliminary insight into the mechanism indicates that such an oxidative C−O/N cross‐coupling reaction proceeds by masking the aldehyde in a nucleophilic addition reaction with an alkoxy/amino source, thereby keeping the highly reactive formyl group from undesired oxidation. This protocol for the oxidative esterification and amidation of aldehydes proceeds through two different pathways that are characterized by the intrinsic nucleophilicity of the alkanol and amine substrates The former occurs in the presence of p‐CH3C6H4SO3H as a cocatalyst and orthoformates as the alkoxy sources, instead of alkanols, to efficiently afford the transient acetals. In contrast, the coupling of the more nucleophilic amines with aldehydes renders a readily accessible cross‐coupling reaction that occurs without any cocatalyst but is limited by the potential inhibition of THICA upon nucleophilic substitution by an amine. Consequently, only sterically hindered amines were tolerated in this catalytic system, whereas further condensation occurred in the presence of primary amines to lead to imines.
Site‐Selective δ‐C(sp3)−H Alkylation of Amino Acids and Peptides with Maleimides via a Six‐Membered Palladacycle
Authors: Zhan Bei‐Bei , Li Ya , Xu Jing‐Wen , Nie Xing‐Liang , Fan Jun , Jin Liang , Shi Bing‐Feng 
Published: March 2018

AbstractThe site‐selective functionalization of unactivated C(sp3)−H bonds remains one of the greatest challenges in organic synthesis. Herein, we report on the site‐selective δ‐C(sp3)−H alkylation of amino acids and peptides with maleimides via a kinetically less favored six‐membered palladacycle in the presence of more accessible γ‐C(sp3)−H bonds. Experimental studies revealed that C−H bond cleavage occurs reversibly and preferentially at γ‐methyl over δ‐methyl C−H bonds while the subsequent alkylation proceeds exclusively at the six‐membered palladacycle that is generated by δ‐C−H activation. The selectivity can be explained by the Curtin–Hammett principle. The exceptional compatibility of this alkylation with various oligopeptides renders this procedure valuable for late‐stage peptide modifications. Notably, this process is also the first palladium(II)‐catalyzed Michael‐type alkylation reaction that proceeds through C(sp3)−H activation.
A [RuRu] Analogue of an [FeFe]‐Hydrogenase Traps the Key Hydride Intermediate of the Catalytic Cycle
Authors: Sommer Constanze , Richers Casseday P. , Lubitz Wolfgang , Rauchfuss Thomas B. , Reijerse Edward J. 
Published: March 2018

AbstractThe active site of the [FeFe]‐hydrogenases features a binuclear [2Fe]H sub‐cluster that contains a unique bridging amine moiety close to an exposed iron center. Heterolytic splitting of H2 results in the formation of a transient terminal hydride at this iron site, which, however is difficult to stabilize. We show that the hydride intermediate forms immediately when [2Fe]H is replaced with [2Ru]H analogues through artificial maturation. Outside the protein, the [2Ru]H analogues form bridging hydrides, which rearrange to terminal hydrides after insertion into the apo‐protein. H/D exchange of the hydride only occurs for [2Ru]H analogues containing the bridging amine moiety.
Spectroscopic Identification of H2NSO and syn‐ and anti‐HNSOH Radicals
Authors: Dong Xuelin , Deng Guohai , Wu Zhuang , Xu Jian , Lu Bo , Trabelsi Tarek , Francisco Joseph S. , Zeng Xiaoqing 
Published: March 2018

AbstractThe simplest aminosulfinyl radical H2NSO has been generated in the gas phase through flash vacuum pyrolysis of CF3S(O)NH2 at approximately 1000 K. Upon UV light irradiation (365 nm), 1,3‐H migration occurs in H2NSO and furnishes an elusive N‐amidyl radical HNSOH in syn and anti conformations in cryogenic matrices (N2 or Ar, 15 K). Further 266 nm laser irradiation results in dissociation of HNSOH to H2O and SN and concomitant reformation of H2NSO in trace amount. The identification of H2NSO, syn‐HNSOH, and anti‐HNSOH by matrix‐isolation IR spectroscopy is supported by high‐level quantum chemical computations.
Electrospinning of poly(γ‐benzyl–α,L‐glutamate) microfibers for piezoelectric polymer applications
Authors: Nguyen Duc‐Nam , Yu S. Michael , Moon Wonkyu 
Published: March 2018

ABSTRACTOne of the latest developments in the field of piezoelectric polymers is the use of poly(γ‐benzyl‐α,L‐glutamate) (PBLG), a poly(amino acid) that can be poled along its α‐helical axis and fabricated into thermally stable piezoelectric microfibers via electrospinning. This study demonstrates a method for improving the piezoelectricity of electrospun PBLG microfibers by controlling the orientation of fibers using a method based on a concentrated electric field. The piezoelectricity is verified via customized quasi‐static and dynamic measurement methods, while the correlation between fiber alignment and the piezoelectric constant, d33, in the longitudinal mode of the electrospun PBLG fibers is investigated. When the level of alignment was varied from 50% to 90%, the piezoelectric constant increased linearly, showing a maximum d33 of 27 pC N−1 and a maximum force sensitivity of 65 mV N−1 at peak alignment. A fabricated flexible prototype based on electrospun PBLG fibers provides a new solution for the use of PBLG fibers in wearable energy harvesters or composites based on piezoelectric polymer fibers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46440.
One‐step facile process to obtain insoluble polysaccharides fibrous mats from electrospinning of water‐soluble PMDA/cyclodextrin polymer
Authors: Cecone Claudio , Caldera Fabrizio , Anceschi Anastasia , Scalarone Dominique , Trotta Francesco , Bracco Pierangiola , Zanetti Marco 
Published: March 2018

ABSTRACTHerein, we used an electrospinning process to develop nanofibers based on poly‐cyclodextrin. This article describes a simple and effective method to produce fibers of a water‐soluble hyperbranched polymer based on β‐CD and pyromellitic dianhydride via electrospinning. The obtained fibers were made insoluble in water with a simple thermal crosslinking without the use of further reactive or solvent. After 24 h of dipping in distilled water or phosphate buffer solution morphology and size of fibers remain unaltered as observed in scanning electron microscopy. The crosslinking mechanism was studied with thermogravimetric analysis, attenuated total reflectance–Fourier infrared spectroscopy, and elemental analysis and a reaction mechanism is proposed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46490.
Optimal model‐based control of non‐viral siRNA delivery
Authors: Jamili Elnaz , Dua Vivek 
Published: March 2018

AbstractFurther quantitative understanding of the biological effects and mechanisms involved in cellular and intracellular delivery of nucleic acid materials is required to produce clinical applications of gene therapy. Several modeling approaches have been used in this field; however, a comprehensive approach that integrates all the key pharmacological issues into a holistic framework that is applicable for in vivo conditions is still lacking. This contribution presents a pharmacokinetic/pharmacodynamic model‐based control study of non‐viral siRNA delivery describing the dynamics of the delivery process and takes into account the main multi‐objective optimization issues such as efficacy and toxicity, as well as the effect of uncertainty in cell doubling time. The methodology developed in this work is used to predict the optimal dosage injection rate and optimal intracellular exposure of siRNAs in order to improve the pharmacological effects before cell division occurs. The present analysis successfully provides quantitative predictions of non‐viral siRNA activity paving the path for further experimental work to probe more efficient delivery systems.