bluuebunny/crossref_metadata_2025_split huggingface dataset:
A liquid chromatography–tandem mass spectrometry method for preclinical pharmacokinetics and tissue distribution of hydrolyzable tannins chebulinic acid and chebulagic acid in rats
Authors: Lu Ying , Yan Huiyu , Teng Shiyong , Yang Xige 
Published: November 2018

AbstractA simple and sensitive liquid chromatography–tandem mass spectrometry method was developed for the simultaneous determination of chebulinic acid and chebulagic acid in rat plasma and tissues and well used in the pharmacokinetic and tissue distribution studies after intraperitoneal injection administration. Samples were processed with methanol by protein precipitation, and chromatographic separation was performed on an Agilent Zorbax SB‐C18 column (50 × 2.1 mm, 1.8 μm) with a mobile phase consisting of methanol and water containing 0.1% formic acid (60:40, v/v). Quantification was performed by selected reaction monitoring with m/z 977.1 → 806.8 for chebulagic acid, m/z 979.0 → 808.7 for chebulinic acid and m/z 851.2 → 704.9 for the internal standard. Good linearity was observed over their respective concentration range. The pharmacokinetic study showed that both compounds reached their peak concentration values (605.8 ± 35.6 ng/mL for chebulinic acid and 1327.1 ± 118.6 ng/mL for chebulagic acid) at the same time of 0.9 h following intraperitoneal injection administration. The two compounds could be detected in blood‐abundant tissues. The kidney had the highest concentrations (462.6 ± 138.5 ng/g for chebulinic acid and 1651.7 ± 167.7 ng/g for chebulagic acid) at 1 h post‐dose, followed by the heart, liver, spleen and lung.
Exfoliated NiFe Layered Double Hydroxide Cocatalyst for Enhanced Photoelectrochemical Water Oxidation with Hematite Photoanode
Authors: Park Yoon Bin , Kim Ju Hun , Jang Youn Jeong , Lee Jin Ho , Lee Min Hee , Lee Byeong Jun , Youn Duck Hyun , Lee Jae Sung 
Published: November 2018

AbstractIn photoelectrochemical (PEC) water oxidation, a low onset potential and a high photocurrent are desired and a cocatalyst on the photoanode could improve the performance. For better use of a NiFe layered double hydroxide (LDH) cocatalyst, concept of exfoliation is applied. Exfoliation gives higher electrochemical surface area and better water oxidation kinetics, which is reflected in improved charge injection efficiency at low bias potentials. Exfoliated NiFe LDH shows increased photocurrent density by 50 % at 1.0 VRHE and reduced onset potential by 140 mV relative to those of stacked bulk LDH under 1 sun illumination, making it a much more effective cocatalyst for α‐Fe2O3 photoanode. The intensity modulated photocurrent spectroscopy shows that the improved photocurrents and early onset potentials of exfLDH/α‐Fe2O3 photoanode are attributed to fast charge transfer and, more importantly, suppressed charge recombination due to passivation of α‐Fe2O3 surface by the LDH monolayer sheet.
Crystallization of Sodium Salt of Organic Acid as Example for Neutral Salt Recovery of Bio Acids
Authors: Plate Hermann , van Esch Jan 
Published: November 2018

AbstractThe optimization of an organic acid production process downstream of fermentation is presented. Sodium salt solution of the organic acid (Na salt) solution is the product in the industrial fermentation process for the organic acid production and until today, it has not been attempted to directly crystallize/isolate the Na salt under these circumstances. Evaporation crystallization of Na salt directly from the solid‐free fermentation broth without purification can be realized with high product purity. Parameters limiting the crystallization/separation process are identified and discussed. The above points are considered as a function of viscosity, crystal size, and product purity. Comparison with the existing process completes this evaluation. The impact on the process design and alternatives are illustrated. The modification of hybrid processes using crystallization also as a purification step is investigated.
Beware of r2 even for test datasets: Using the latest measured y‐values (r2LM) in time series data analysis
Authors: Kaneko Hiromasa 
Published: November 2018

AbstractThe determination coefficient of a test dataset, r2, is calculated and used to compare the performance of adaptive soft sensors and discuss the possibility of their practical use. However, soft sensors that give very high r2 values do not always have sufficient predictive accuracy for use in process control. Therefore, a new measure for soft sensors based on the latest measured y‐values (r2LM) is proposed. This metric can be used in time series data analysis to determine whether the variations in y‐values estimated by soft sensors come from variations in the input variables or those of the latest measured y‐values. Through case studies using real and simulated datasets, it is confirmed that low r2LM values correspond to meaningless soft sensors, even when their r2 value is high, and that high r2LM values imply that the estimation results are useful for process control with soft sensors. Python and MATLAB codes for computing r2LM can be downloaded from GitHub: https://github.com/hkaneko1985/r2lm.
Self‐Healing Polymer Electrolytes Formed via Dual‐Networks: A New Strategy for Flexible Lithium Metal Batteries
Authors: Zhou Binghua , Zuo Cai , Xiao Zhuliu , Zhou Xingping , He Dan , Xie Xiaolin , Xue Zhigang 
Published: November 2018

AbstractA novel polymer electrolyte with mechanically robust and self‐healing properties was fabricated through a dual‐network structure, crosslinked by quadruple hydrogen bonding and chemical bonding. The dynamic ureido‐pyrimidinone (UPy) dimers were the first network in the polymer matrix. This group endows the polymer electrolyte with good self‐healing capacity and improves the reliability and lifetime of the polymer lithium batteries. The crosslinked polyethylene glycol‐bis‐carbamate dimethacrylate (PEGBCDMA) is the second network and guarantees dimensional stability and good mechanical properties of the polymer electrolyte. The dual‐network self‐healing polymer electrolyte (DN‐SHPE) exhibits improved ionic conductivity versus the polymer electrolyte fabricated by poly(ethylene glycol) diacrylate (PEGDA). It has high thermal stability (up to 350 °C) and excellent interfacial stability with the electrodes. When the DN‐SHPE‐based cells were fabricated with LiFePO4 and Li metal, the resulting cells show good reversible specific capacity and considerable rate capability. Moreover, the pouch cell could maintain electrochemical function even under deformation or folding conditions.
Total Synthesis of Callyspongiolide, Part 2: The Ynoate Metathesis/cis‐Reduction Strategy
Authors: Wölfl Bernhard , Mata Guillaume , Fürstner Alois 
Published: November 2018

AbstractThe macrocyclic core of the cytotoxic marine natural product callyspongiolide (1) was forged by ring‐closing alkyne metathesis (RCAM) of an ynoate precursor using a molybdenum alkylidyne complex endowed with triarylsilanolate ligands as the catalyst. This result is remarkable in view of the failed attempts documented in the literature at converting electron deficient alkynes with the aid of more classical catalysts. The subsequent Z‐selective semi‐reduction of the resulting cycloalkyne by hydrogenation over nickel boride required careful optimization in order to minimize overreduction and competing dehalogenation of the compound's alkenyl iodide terminus as needed for final attachment of the side chain of 1 by Sonogashira coupling. The required cyclization precursor itself was prepared via Kocienski olefination.
Dehalogenation of Halogenated Nucleobases and Nucleosides by Organoselenium Compounds
Authors: Mondal Santanu , Mugesh Govindasamy 
Published: November 2018

AbstractHalogenated nucleosides, such as 5‐iodo‐2′‐deoxyuridine and 5‐iodo‐2′‐deoxycytidine, are incorporated into the DNA of replicating cells to facilitate DNA single‐strand breaks and intra‐ or interstrand crosslinks upon UV irradiation. In this work, it is shown that the naphthyl‐based organoselenium compounds can mediate the dehalogenation of halogenated pyrimidine‐based nucleosides, such as 5‐X‐2′‐deoxyuridine and 5‐X‐2′‐deoxycytidine (X=Br or I). The rate of deiodination was found to be significantly higher than that of the debromination for both nucleosides. Furthermore, the deiodination of iodo‐cytidines was found to be faster than that of iodo‐uridines. The initial rates of the deiodinations of 5‐iodocytosine and 5‐iodouracil indicated that the nature of the sugar moiety influences the kinetics of the deiodination. For both the nucleobases and nucleosides, the deiodination and debromination reactions follow a halogen‐bond‐mediated and addition/elimination pathway, respectively.
Synthesis of Bis(phosphanyl)alkane Monosulfides by the Addition of Diphosphane Monosulfides to Alkenes under Light
Authors: Sato Yuki , Kawaguchi Shin‐ichi , Nomoto Akihiro , Ogawa Akiya 
Published: November 2018

AbstractBis‐phosphanated compounds are regarded as the most ubiquitous privileged ligand structures in transition‐metal catalysis. The development of highly atom economical reactions is of great importance for their syntheses because less atom economical methods often require complicated purification procedures under inert atmospheres to remove excess starting materials and byproducts. Herein, the photoinduced addition reactions of diphosphane monosulfides bearing PV(S)−PIII single bonds to alkenes is disclosed. These reactions require only equimolar amounts of the diphosphane monosulfide relative to the alkene and facilitate highly selective introduction of two different types of phosphorus‐containing groups, such as thiophosphoryl and phosphanyl groups, into a variety of alkenes without any catalyst, base, or additive.
Robust Icephobic Performance of Flexible Needles
Authors: Liu Xuejuan , Zhao Hongbin , Li Peiliu , Pang Yan , Fan Yuzun , Zhang Bo , Wang Lei , Zheng Yongmei , Wang Zuankai 
Published: November 2018

AbstractSuperhydrophobic micro‐/nanopatterned structures exhibit robust water/ice repellence in harsh environments, which is significant for theoretical study and industrial applications such as cooling in nuclear power, heat transfer, and self‐cleaning for aircraft. However, the reported studies regarding icephobic functional surfaces based on rigid materials have indicated potential dangers in applications, e. g., the roughness topographies are easily ruined in the icing process, which limits further application and study. In this study, polydimethylsiloxane‐based flexible microneedles (FNs) with ZnO nanorods are designed and fabricated and further characterized with robust icephobicity at a temperature of 0 °C. In this system, the flexible microneedles could bend to match the deformation caused by icing from condensed droplets, resulting in protecting the nanorods on its surface, which is significantly promising for durable icephobicity in harsh environments.
t‐Si64: A Novel Silicon Allotrope
Authors: Fan Qingyang , Niu Rui , Zhang Wenzhu , Zhang Wei , Ding Yingchun , Yun Sining 
Published: November 2018

AbstractUtilizing first principle calculations, a novel Si64 silicon allotrope in the I41/amd space group with tetragonal symmetry (denoted as t‐Si64 below) is proposed in this work. In addition, also its structural, anisotropic mechanical, and electronic properties along with its minimum thermal conductivity κmin were predicted. The mechanical and thermodynamic stability of t‐Si64 were evaluated by means of elastic constants and phonon spectra. The electronic band structure indicates that t‐Si64 is an indirect band gap semiconductor with a band gap: 0.67 eV (primitive cell) compared to a direct band gap of 0.70 eV with respect to a conventional cell. The minimum thermal conductivity of t‐Si64 (0.74 W cm−1 K−1) is much smaller than that of diamond silicon (1.13 W cm−1 K−1). Therefore, Si−Ge alloys in the I41/amd space group are potential thermoelectric materials.
Anabaena sp. strain PCC 7120: Laboratory Maintenance, Cultivation, and Heterocyst Induction
Authors: Videau Patrick , Cozy Loralyn M. 
Published: November 2018

AbstractAnabaena sp. strain PCC 7120 is a multicellular, filamentous, freshwater cyanobacterium that is capable of differentiating specialized heterocyst cells for nitrogen fixation. This unit includes protocols for the growth and maintenance of Anabaena appropriate for a research or teaching laboratory. Controlled induction and assessment of heterocyst development is also covered. © 2018 by John Wiley & Sons, Inc.
Integrated potentiostat for detection of Chagas disease
Authors: Agis Leonardo , Torres Fabián , Gak Joel , Miguez Matías 
Published: November 2018

SummaryThe design of a low‐power‐integrated potentiostat that measures electric current intended for a Chagas disease detection application is presented. This circuit can generate and measure currents from 1 to 10 μA with a relative error under 5%. The remaining part of the circuit consumes only 1.5 μA. The circuit was designed using the 0.6 μm XC06 technology from the X‐FAB, with a total silicon area of 0.24 mm2 (without pads).
Analysis and design of joint CFO/channel estimate techniques for a cooperative STBC‐OFDM system
Authors: Lin Tsui‐Tsai , Hwang Fuh‐Hsin 
Published: November 2018

SummaryThis paper studies the joint estimation technique of carrier frequency offset (CFO) and channel information for a distributed decode‐and‐forward (DF) cooperative space‐time block‐coded (STBC) orthogonal frequency division multiplexing (OFDM) system. For the considered relay system, we provide theoretical analysis of the effects upon the output signal‐to‐noise ratio (SNR), which is caused by the CFO/channel estimation error. Based on the provided analytical results, a joint CFO/channel estimation scheme is then developed, where the CFO estimate is achieved by a multiple‐dimensional linear search algorithm. Furthermore, we propose an alternative estimation solution with iteration approach being designed for the CFO estimation prior to the channel estimation. In contrast to the former estimator, the iterative method enjoys the advantage of the substantially reduced implementation complexity without sacrificing the estimate performance. The conducted computer simulation results verify the effectiveness of the proposed schemes.
Genetic and chemical divergence among host races of a socially parasitic ant
Authors: Torres Candice W. , Tonione Maria A. , Ramírez Santiago R. , Sapp Joseph R. , Tsutsui Neil D. 
Published: November 2018

AbstractHost–parasite associations facilitate the action of reciprocal selection and can drive rapid evolutionary change. When multiple host species are available to a single parasite, parallel specialization on different hosts may promote the action of diversifying natural selection and divergence via host race formation. Here, we examine a population of the kidnapper ant (Polyergus mexicanus) that is an obligate social parasite of three sympatric ant species: Formica accreta, F. argentea, and F. subaenescens (formerly F. fusca). Behavioral and ecological observations of P. mexicanus have shown that individual colonies parasitize only one species of host and that new Polyergus queens maintain host fidelity when establishing new colonies. To successfully adapt to a particular host, Polyergus ants may mimic or camouflage themselves with the species‐specific chemical cues (cuticular hydrocarbons) that their hosts use to ascertain colony membership. To investigate the extent of host specialization, we collected both genetic and chemical data from P. mexicanus that parasitize each of the three different Formica species in sympatry. We show that host‐associated genetic structure exists for both maternally inherited mitochondrial DNA data and biparentally inherited microsatellite markers. We also show that P. mexicanus can be distinguished by chemical profile according to host due to partial matching with their host. Our results support the hypothesis that host race formation is occurring among lineages of P. mexicanus that use different Formica hosts. Thus, this system may represent a promising model for illuminating the early steps of divergence, accumulation of reproductive isolation, and speciation.
Response of soil organic carbon to vegetation degradation along a moisture gradient in a wet meadow on the Qinghai–Tibet Plateau
Authors: Alhassan Abdul‐Rauf Malimanga , Ma Weiwei , Li Guang , Jiang Zhirong , Wu Jiangqi , Chen Guopeng 
Published: November 2018

AbstractThe study was conducted during the growing seasons of 2013, 2014, and 2015 in the wet meadows on the eastern Qinghai–Tibet plateau (QTP) in the Gansu Gahai Wetland Nature Reserve to determine the dynamics of soil organic carbon (SOC) as affected by vegetation degradation along a moisture gradient and to assess its relationship with other soil properties and biomass yield. Hence, we measured SOC at depths of 0–10, 10–20, and 20–40 cm under the influence of four categories of vegetation degradation (healthy vegetation [HV], slightly degraded [SD], moderately degraded [MD], and heavily degraded [HD]). Our results showed that SOC decreased with increased degree of vegetation degradation. Average SOC content ranged between 36.18 ± 4.06 g/kg in HD and 69.86 ± 21.78 g/kg in HV. Compared with HV, SOC content reduced by 30.49%, 42.22%, and 48.22% in SD, MD, and HD, respectively. SOC significantly correlated positively with soil water content, aboveground biomass, and belowground biomass, but significantly correlated negatively with soil temperature and bulk density (p < 0.05). Highly Significant positive correlations were also found between SOC and total nitrogen (p = 0.0036), total phosphorus (p = 0.0006) and total potassium (p < 0.0001). Our study suggests that severe vegetation and moisture loss led to approximately 50% loss in SOC content in the wet meadows, implying that under climate warming, vegetation and soil moisture loss will dramatically destabilize carbon sink capacities of wetlands. We therefore suggest wetland hydrological management, restoration of vegetation, plant species protection, regulation of grazing activities, and other anthropogenic activities to stabilize carbon sink capacities of wetlands.
Seismic response of bridge piers on pile groups for different soil damping models and lumped parameter representations of the foundation
Authors: González Francisco , Padrón Luis A. , Carbonari Sandro , Morici Michele , Aznárez Juan J. , Dezi Francesca , Leoni Graziano 
Published: November 2018

SummaryThis paper presents a wide parametric study aimed at elucidating the influence, on the computed seismic response of bridge piers, of two related aspects of the model: (1) the adoption of the classical hysteretic or the causal Biot's damping models for the soil and (2) the use of two different lumped parameter models of different complexity and accuracy to approximate the impedances of the pile foundation. A total of 2072 cases, including different superstructures, pile foundations, soil deposits, and seismic input signals, are studied. The results are presented so that the influence of the different parameters involved in the analysis can be assessed. From an engineering point of view, both lumped parameter models provide, in general, sufficiently low errors. The choice of the most adequate model for each case will depend not only on the configuration of the structure and the soil‐foundation system but also on the assumed soil damping model, whose influence on the computed seismic responses is relevant in many cases. The nonphysical behaviour provided by the classical hysteretic damping model for the soil at zero frequency generates issues in the process of fitting the impedance functions. It is also found that larger deck displacements are predicted by Biot's model due to the higher damping at low frequencies provided by the classical hysteretic damping model.
Do hedge funds time market tail risk? Evidence from option‐implied tail risk
Authors: Shin Jung‐Soon , Kim Minki , Oh Dongjun , Kim Tong Suk 
Published: November 2018

AbstractThis paper focuses on an unexplored dimension of fund managers’ timing ability: Market‐wide tail risk implied by information in options markets. Constructing the option‐implied tail risk, we investigate whether hedge fund managers can strategically time the tail risk through adjusting their exposure to changes of it. Using an extensive sample of equity‐oriented hedge funds, we find strong evidence of tail risk timing ability of hedge fund managers. Furthermore, tail risk timing ability brings significant economic value to investors. Top‐ranked funds outperform bottom‐ranked funds by 5–7% annually after adjusting for risk factors. Our results are robust to various robustness checks.
Long‐term dynamics of the VIX index and its tradable counterpart VXX
Authors: Bašta Milan , Molnár Peter 
Published: November 2018

AbstractWe study the relationship of the VIX index and the exchange‐traded note VXX on various timescales. We find that changes of VIX and VXX are correlated only contemporaneously on timescales of days, but VIX leads VXX on timescales of months. Next, we construct a simple joint model for VXX and VIX which replicates all the key characteristics of these two time series, but in which VIX and VXX are related only via a correlated error term. Therefore, VIX cannot be used as a predictor of VXX and there is no apparent trading profit opportunity.
Detrital zircon U–Pb ages from the Middle to Late Permian strata of the Yiyang area, southern North China Craton: Implications for the Mianlue oceanic crust subduction
Authors: Wang Yanpeng , Yang Wentao , Zheng Deshun , Zuo Pengfei , Qi Shuaishuai 
Published: November 2018

Basin formation and sedimentary development in the southern North China Craton (NCC) are closely related to the tectonic evolution of the Qinling Orogenic Belt (QOB). With the aim of revealing the coupling evolution between the QOB and southern NCC during the Late Palaeozoic, an investigation based on provenance analysis was performed in this study. We present new detrital zircon U–Pb data from the Middle–Late Permian sediments in the Yiyang area, southern NCC. The results show that detrital zircons, from the Middle Permian Shihezi Formation, have three major peaks at 2,447, 1,905, and 296 Ma. In contrast, the lower and upper parts of the Late Permian Sunjiagou Formation yield major peaks at ~1.85 Ga and ~260 Ma, with weak peaks at ~2.5 Ga, ~450 Ma, and ~315 Ma, and the middle part of the Sunjiagou Formation displays a major peak at 429 Ma. Combined with published palaeocurrent data and lithofacies palaeogeography, the sediments of the Middle Permian Shihezi Formation were sourced from the Inner Mongolia Palaeo‐Uplift along the northern margin of the NCC, whereas the Upper Permian Sunjiagou Formation originated mainly from the southern margin of the NCC including the North Qinling Belt. This provenance shift indicates that the North Qinling Belt and southern margin of the NCC initiated the uplift and exhumation during the Late Permian. On the basis of the evolutionary history of the QOB, we attribute the uplift geodynamics to the Mianlue oceanic crust subduction. This study provides important sedimentological constraints for the tectonic conversion during the Late Palaeozoic along the southern margin of the NCC, which also restricts the start‐up time of the Mianlue oceanic crust subduction from the perspective of the basin–mountain system.