bluuebunny/crossref_metadata_2025_split huggingface dataset:
Piezoresistive Sensors Based on rGO 3D Microarchitecture: Coupled Properties Tuning in Local/Integral Deformation
Authors: Xu Minxuan , Li Feng , Zhang Zhenyun , Shen Tao , Qi Junjie 
Published: November 2018

AbstractAn ideal flexible piezoresistive sensor should possess high sensitivity as well as wide sensing range, and provide a stable and excellent response under different deformation, such as local and integral strain. However, these properties are difficult to achieve simultaneously with conventional all‐polymer‐filled composite, as tuning of one material component always causes the unpredictable change of multiple properties. Here, a strategy is developed to realize a reduced graphene oxide (rGO) based three‐dimensional (3D) microarchitecture, where the electrical conductivity and mechanical elasticity of the composite can be tuned simultaneously by only varying the rGO weight fraction. The analysis of coupled properties tuning effect shows that the device applied in local deformation reveals a greater dependence on electrical property, which prefers to low rGO weight fraction and displays a high sensitivity of 0.72 kPa−1 in the 10 kPa linear region. The sensor used for integral deformation is dominated by the mechanical property, which prefers to high rGO weight fraction and shows a gauge factor of 2517 at tensile strain of 100%, far superior to that previously reported. The rationally designed 3D microarchitecture is scalable, low cost, and promising in human–computer interactions, including but not limited to human health monitoring and intelligent wearable keyboards.
Improved Cycling Performance of Li‐Excess Cation‐Disordered Cathode Materials upon Fluorine Substitution
Authors: Lun Zhengyan , Ouyang Bin , Kitchaev Daniil A. , Clément Raphaële J. , Papp Joseph K. , Balasubramanian Mahalingam , Tian Yaosen , Lei Teng , Shi Tan , McCloskey Bryan D. , Lee Jinhyuk , Ceder Gerbrand 
Published: November 2018

AbstractThe recent discovery of Li‐excess cation‐disordered rock salt cathodes has greatly enlarged the design space of Li‐ion cathode materials. Evidence of facile lattice fluorine substitution for oxygen has further provided an important strategy to enhance the cycling performance of this class of materials. Here, a group of Mn3+–Nb5+‐based cation‐disordered oxyfluorides, Li1.2Mn3+0.6+0.5xNb5+0.2−0.5xO2−xFx (x = 0, 0.05, 0.1, 0.15, 0.2) is investigated and it is found that fluorination improves capacity retention in a very significant way. Combining spectroscopic methods and ab initio calculations, it is demonstrated that the increased transition‐metal redox (Mn3+/Mn4+) capacity that can be accommodated upon fluorination reduces reliance on oxygen redox and leads to less oxygen loss, as evidenced by differential electrochemical mass spectroscopy measurements. Furthermore, it is found that fluorine substitution also decreases the Mn3+‐induced Jahn–Teller distortion, leading to an orbital rearrangement that further increases the contribution of Mn‐redox capacity to the overall capacity.
Pyrene‐Fused Pyrazaacenes with Eight Rectilinearly Arranged Aromatic Rings
Authors: Wang Chuan‐Zeng , Feng Xing , Elsegood Mark R. J. , Warwick Thomas G. , Teat Simon J. , Redshaw Carl , Bi Yu‐Sui , Yamato Takehiko 
Published: November 2018

AbstractA series of pyrene‐fused azaacene‐type conjugated molecules containing two pyrazine units and up to eight rectilinearly arranged aromatic rings were prepared by condensation coupling reactions in moderate yields. The geometries and electronic structures associated with 2 and 5 were evaluated by DFT calculations. Photophysical properties indicated that these systems possess delocalized structures, and their optoelectronic properties can be tuned by extending the π‐conjugated length and introducing electronic‐withdrawing groups. The compounds were thoroughly investigated by XRD studies, electrochemistry and DFT calculations. High thermal stability and tunable energy levels make them excellent candidates as a class of organic molecular materials.
A Quantitative Chemical Proteomics Approach for Site‐specific Stoichiometry Analysis of Ubiquitination
Authors: Li Yunan , Evers Jonathan , Luo Ang , Erber Luke , Postler Zachary , Chen Yue 
Published: November 2018

AbstractStoichiometric analysis of post‐translational modifications is an emerging strategy for absolute quantification of the fractional abundance of the modification. Herein, a quantitative chemical proteomic workflow for stoichiometric analysis of ubiquitination is reported, named isotopically balanced quantification of ubiquitination (IBAQ‐Ub). The strategy utilizes a new amine‐reactive chemical tag (AcGG‐NHS) that is structurally homologous to the GG remnant of ubiquitin on modified lysine after trypsin cleavage and therefore enables the generation of structurally identical peptides from ubiquitinated and unmodified lysine residues following trypsin digestion and secondary stable isotopic labeling. The strategy is highly robust, sensitive, and accurate with a wide dynamic range using either protein standards or complex cell lysates. Thus, this work provides an efficient chemical proteomics tool for quantitative stoichiometric analysis of ubiquitination signaling pathways.
C‐H‐Funktionalisierung von Standardpolymeren
Authors: Williamson Jill B. , Lewis Sally E. , Johnson Robert R. , Manning Irene M. , Leibfarth Frank A. 
Published: November 2018

AbstractDie präparative Modifizierung von Polymersubstraten ist eine der ältesten und zuverlässigsten Methoden zur Erhöhung der funktionellen Vielfalt von weichen Materialien. Bei der Modifizierung der chemischen Struktur von Polymeren, die bereits in großem Maßstab hergestellt werden, wird die jetzige kostengünstige Massenproduktion von Standardkunststoffen für die Erschließung moderner Materialien genutzt. Es wurden unzählige Methoden zur C‐H‐Funktionalisierung von Polymeren entwickelt, die die Modifizierung von Materialeigenschaften sowohl im Labormaßstab als auch im industriellen Maßstab ermöglichen. Vorangetrieben durch Fortschritte bei der C‐H‐Aktivierung, in der Photoredoxkatalyse und in der Radikalchemie, haben sich in letzter Zeit chemoselektive Methoden zu einem Weg entwickelt, um Standardpolymersubstraten eine bestimmte Funktionalität zu verleihen. Dieser Aufsatz erörtert die historische Bedeutung und die aktuellen Fortschritte der C‐H‐Funktionalisierung von Standardpolymeren. Der konzeptionelle Ansatz, über den hier ein Überblick gegeben wird, verspricht interessante neue Entwicklungsrichtungen für das Gebiet, einschließlich der Erhöhung des Wertes von überall vorhandenen Materialien, der Entdeckung vollkommen neuer Materialeigenschaften und der Einführung eines gangbaren Weges für das Upcycling von nach Gebrauch anfallenden Kunststoffabfällen.
Lateral Adsorbate Interactions Inhibit HCOO− while Promoting CO Selectivity for CO2 Electrocatalysis on Silver
Authors: Bohra Divya , Ledezma‐Yanez Isis , Li Guanna , de Jong Wiebren , Pidko Evgeny A. , Smith Wilson A. 
Published: November 2018

AbstractAg is a promising catalyst for the production of carbon monoxide (CO) via the electrochemical reduction of carbon dioxide (CO2ER). Herein, we study the role of the formate (HCOO−) intermediate *OCHO, aiming to resolve the discrepancy between the theoretical understanding and experimental performance of Ag. We show that the first coupled proton‐electron transfer (CPET) step in the CO pathway competes with the Volmer step for formation of *H, whereas this Volmer step is a prerequisite for the formation of *OCHO. We show that *OCHO should form readily on the Ag surface owing to solvation and favorable binding strength. In situ surface‐enhanced Raman spectroscopy (SERS) experiments give preliminary evidence of the presence of O‐bound bidentate species on polycrystalline Ag during CO2ER which we attribute to *OCHO. Lateral adsorbate interactions in the presence of *OCHO have a significant influence on the surface coverage of *H, resulting in the inhibition of HCOO− and H2 production and a higher selectivity towards CO.
Control of Metal–Organic Framework Crystallization by Metastable Intermediate Pre‐equilibrium Species
Authors: Yeung Hamish H.‐M. , Sapnik Adam F. , Massingberd‐Mundy Felicity , Gaultois Michael W. , Wu Yue , Fraser Duncan A. X. , Henke Sebastian , Pallach Roman , Heidenreich Niclas , Magdysyuk Oxana V. , Vo Nghia T. , Goodwin Andrew L. 
Published: November 2018

AbstractThere is an increasing amount of interest in metal–organic frameworks (MOFs) for a variety of applications, from gas sensing and separations to electronics and catalysis. However, the mechanisms by which they crystallize remain poorly understood. Herein, an important new insight into MOF formation is reported. It is shown that, prior to network assembly, crystallization intermediates in the canonical ZIF‐8 system exist in a dynamic pre‐equilibrium, which depends on the reactant concentrations and the progress of reaction. Concentration can, therefore, be used as a synthetic handle to directly control particle size, with potential implications for industrial scale‐up and gas sorption applications. These findings enable the rationalization of apparent contradictions between previous studies of ZIF‐8 and opens up new opportunities for the control of crystallization in network solids more generally.
Black Phosphorus: Bioactive Nanomaterials with Inherent and Selective Chemotherapeutic Effects
Authors: Zhou Wenhua , Pan Ting , Cui Haodong , Zhao Zhen , Chu Paul K. , Yu Xue‐Feng 
Published: November 2018

AbstractBlack phosphorus nanosheets (BPs) are demonstrated to be highly bioactive anti‐cancer agents because of their inherent and selective chemotherapeutic effects. Fast intracellular biodegradation of BPs and acute elevation of phosphate anions were observed from different types of cancer cells due to the stronger intracellular oxidative stress and accelerated energy metabolism, but normal cells are not affected. Selective biodegradation of BPs induced G2/M phase arrest and subsequent apoptosis‐ and autophagy‐mediated cell death in cancer cells but not normal cells. The selectivity was superior to that of the traditional chemotherapeutic agent, doxorubicin (DOX). In vivo assessment confirmed the efficiency of BPs in suppressing tumor growth. This study provides insights into nanostructured bioactive anti‐cancer agents and reveals a new direction for nanomedicine research.
Catalytic Enantioselective α‐Ketol Rearrangement
Authors: Wu Hua , Andres Rémi , Wang Qian , Zhu Jieping 
Published: November 2018

AbstractA highly enantioselective α‐ketol rearrangement has been developed. In the presence of a chiral Cu‐bisoxazoline complex, achiral β‐hydroxy‐α‐dicarbonyls were isomerized to chiral α‐hydroxy‐β‐dicarbonyls and their bicyclic derivatives in excellent yields and enantioselectivities. Enantioenriched 2‐acyl‐2‐hydroxy cyclohexan‐1‐ones, dihydroxyhexahydrobenzofuranones, and dihydroxyhexahydro‐cycloheptafuranones, with up to three stereocenters, were readily prepared from achiral starting materials in one operation. The reaction is applicable to the desymmetrization of meso substrates and kinetic resolution of racemic alcohols.
In silico detection of polymorphic microsatellites in the endangered Isis tamarind, Alectryon ramiflorus (Sapindaceae)
Authors: Nichols Joel , Conroy Gabriel C. , Kasinadhuni Naga , Lamont Robert W. , Ogbourne Steven M. 
Published: November 2018

Premise of the StudyAlectryon ramiflorus (Sapindaceae) is an endangered rainforest tree known from only two populations. In this study, we identified polymorphic microsatellites, in silico, improving the effectiveness and efficiency of microsatellite development of nonmodel species. The development of genetic markers will support future conservation management of the species.Methods and ResultsWe used next‐generation sequencing and bioinformatics to detect polymorphic microsatellites, in silico, reducing both the time and cost of marker development. A panel of 15 microsatellites, 12 of which were polymorphic, were subsequently characterized in 64 adult trees representing the entire species range. Mean observed heterozygosity and expected heterozygosity were 0.471 and 0.425, respectively. The polymorphism information content across loci ranged from 0.152 to 0.875.ConclusionsThe microsatellite markers developed in this study will be useful in gaining an understanding of A. ramiflorus’ genetic diversity, level of inbreeding, and population structure and for guiding future restoration and management efforts.
Alkyl Sulfides as Promising Sulfur Sources: Metal‐Free Synthesis of Aryl Alkyl Sulfides and Dialkyl Sulfides by Transalkylation of Simple Sulfides with Alkyl Halides
Authors: Liu Ting , Qiu Renhua , Zhu Longzhi , Yin Shuang‐Feng , Au Chak‐Tong , Kambe Nobuaki 
Published: November 2018

AbstractA site‐selective metal‐free dealkylative approach to synthesize aryl alkyl and symmetrical dialkyl sulfides has been developed. This procedure is convenient and has wide functional group tolerance giving rise to sulfides carrying various alkyl chains from simple alkyl sulfides and alkyl halides in good to excellent yields. This transalkylation proceeds by an ionic mechanism via sulfonium intermediates and it was proposed that dimethylacetamide (DMAC) may participate in part to promote the reaction.
Adaptive Fault‐Tolerant Control of Uncertain MIMO Systems with Reduced Requirement on Desired Trajectory Under Unknown Control Direction
Authors: Jiang Qiqi , Xian Xiaodong , Zhang Zhirong 
Published: November 2018

AbstractThis paper aims at investigating the tracking control problem for a class of multi‐input multi‐output (MIMO) nonlinear systems with non‐square control gain matrix subject to unknown control direction and uncertain desired trajectory. By using the artificial neural network (NN) reconstructs the target trajectory with actual disguised trajectory, we are able to design a practical and stable tracking control scheme without the need for the unavailable desired trajectory. Nussbaum‐type function is incorporated in the control law to handle the unknown control direction. The remarkable feature of the proposed scheme is that it is robust against modeling uncertainties and tolerant to actuation faults, yet guarantees that the closed‐loop system is stable in the sense of ultimately uniformly bounded (UUB). The effectiveness of the proposed control schemes are illustrated through simulation results.
Development of a micelle‐enhanced high‐throughput fluorometric method for determination of niclosamide using a microplate reader
Authors: Abd El‐Hay Soad S. , Belal Fathalla F. 
Published: November 2018

AbstractThe present paper describes the development and validation of a simple and sensitive micelle‐enhanced high‐throughput fluorometric method for the determination of niclosamide (NIC) in 96‐microwell plates. The proposed method is based on the reduction of the nitro group of niclosamide to an amino group using Zn/HCl to give a highly fluorescent derivative that was developed simultaneously and measured at λem 444 nm after excitation at λex 275 nm. Tween‐80 and carboxymethylcellulose (CMC) have been used as fluorescence enhancers and greatly enhanced the fluorescence by factors of 100–150%. The different experimental conditions affecting the fluorescence reaction were carefully investigated and optimized. The proposed method showed good linearity (r2≥ 0.9997) over the concentration ranges of 1–5 and 0.5–5 μg/ml with lower detection limits of 0.01 and 0.008 μg/ml and lower quantification limits of 0.04 and 0.03 μg/ml on using Tween‐80 and or CMC, respectively. The developed high‐throughput method was successfully applied for the determination of niclosamide in both tablets and spiked plasma. The capability of the method for measuring microvolume samples made it convenient for handling a very large number of samples simultaneously. In addition, it is considered an environmentally friendly method with lower consumption of chemicals and solvents.
A multi‐site metastasis‐on‐a‐chip microphysiological system for assessing metastatic preference of cancer cells
Authors: Aleman Julio , Skardal Aleksander 
Published: November 2018

AbstractMetastatic disease remains one of the primary reasons for cancer‐related deaths, yet the majority of in vitro cancer models focus on the primary tumor sites. Here, we describe a metastasis‐on‐a‐chip device that houses multiple bioengineered three‐dimensional (3D) organoids, established by a 3D photopatterning technique employing extracellular matrix‐derived hydrogel biomaterials. Specifically, cancer cells begin in colorectal cancer (CRC) organoid, which resides in a single microfluidic chamber connected to multiple downstream chambers in which liver, lung, and endothelial constructs are housed. Under recirculating fluid flow, tumor cells grow in the primary site, eventually enter circulation, and can be tracked via fluorescent imaging. Importantly, we describe that in the current version of this platform, HCT116 CRC cells preferentially home to the liver and lung constructs; the corresponding organs of which CRC metastases arise the most in human patients. We believe that in subsequent studies this platform can be implemented to better understand the mechanisms underlying metastasis, perhaps resulting in the identification of targets for intervention.
Metabolite identification of tanshinol borneol ester in rats by high‐performance liquid chromatography combined with electrospray ionization quadrupole time‐of‐flight mass spectrometry
Authors: Wang Jie , Ma Cuicui , Li Qiannan , Wang Xing , Yang Yang , Yang Lingjian , Jiang Wei , Liao Sha , Wang Shixiang , Jia Pu , Zhao Ye , Zheng Xiaohui 
Published: November 2018

AbstractTanshinol borneol ester (DBZ) is a potential drug candidate composed of danshensu and borneol. It shows anti‐ischemic and anti‐atherosclerosis activity. However, little is known about its metabolism in vivo. This research aimed to elucidate the metabolic profile of DBZ through analyzing its metabolites using high‐performance liquid chromatography combined with electrospray ionization quadrupole time‐of‐flight mass spectrometry. Chromatographic separation was performed on an Agilent TC‐C18 column (150 × 4.6 mm, 5.0 μm) with gradient elution using methanol and water containing 0.2% (v/v) formic acid as the mobile phase. Metabolite identification involved analyzing the retention behaviors, changes in molecular weights and MS/MS fragment patterns of DBZ and its metabolites. As a result, 20 potential metabolites were detected and tentatively identified in rat plasma, urine and feces after administration of DBZ. DBZ could be metabolized to O‐methylated DBZ, DBZ‐O‐glucuronide, O‐methylated DBZ‐O‐glucuronide, hydroxylated DBZ and danshensu. Danshensu, a hydrolysis product of DBZ, could further be transformed into 12 metabolites. The proposed method was confirmed to be a reliable and sensitive alternative for characterizing metabolic pathways of DBZ and providing valuable information on its druggability.
Drivers and barriers of eco‐innovation types for sustainable transitions: A quantitative perspective
Authors: Kiefer Christoph P. , Del Río González Pablo , Carrillo‐Hermosilla Javier 
Published: November 2018

AbstractFirms are influenced by internal factors (resources and capabilities) and external factors (e.g., regulation) when taking the decision to eco‐innovate. However, the analysis of the internal factors has received much less attention than the external ones. This paper aims to fill this gap in the literature by analyzing the role of resources, competences, and dynamic capabilities (RCCs) as determinants (drivers and barriers) of different eco‐innovation (EI) types. Those EI types contribute differently to the sustainable transition of the economy and society, that is, towards the circular economy. The statistical analyses reveal that RCCs are quite relevant as determinants of EIs, and that different RCCs are more or less relevant for different EI types. In particular, the determinants of systemic and radical EIs substantially differ from those for continuous improvements. Our results suggest that physical RCCs, involvement in green supply chains, an EI‐friendly corporate culture, technology‐push and market‐pull, and internal financing resources represent drivers to these EIs, whereas cooperation, organizational learning, an ISO (International Organization for Standardization) ecological certification, and technological path dependency are barriers. The results may guide firms to pursue competitive and sustainable advantage by innovating through certain EI types corresponding to available and dedicated RCCs. They may also be useful to policy makers who are willing to promote specific EI types.
Extraction and Antioxidant Activities of Magnolia kwangsiensisFiglar & Noot. Leaf Polyphenols
Authors: Zheng Yan‐Fei , Liu Xiong‐Min , Lai Fang 
Published: November 2018

AbstractMicrowave‐assisted extraction was employed to extract polyphenols from the leaf of Magnolia kwangsiensis Figlar & Noot. The yield of polyphenols was 2.44±0.02 % under the optimal conditions of RSM: acetone concentration of 70 %, ratio of solvent to material of 21 mL⋅g−1 and extraction time of 16 min. The antioxidant activities were evaluated in terms of total antioxidant ability, reducing power, DPPH⋅ and ⋅OH scavenging activity. Results showed the polyphenols presented potential antioxidant activities, especially the stronger scavenging activity on ⋅OH. In term of ⋅OH scavenging activity, the IC50 value of NKA‐9 purification was 0.335 mg mL−1, equivalent to 35.23 % of VC. The IC50 values of crude extract and ethyl acetate extract were 0.580 and 0.828 mg mL−1, equivalent to 60.99 % and 87.07 % of VC. Results indicated that M. kwangsiensis leaf polyphenols present potential antioxidant activities that make it beneficial for human health by preventing or reducing oxidative damage.
Reactivity of the Major Product of C5′‐Oxidative DNA Damage in Nucleosome Core Particles
Authors: Rana Anup , Yang Kun , Greenberg Marc M. 
Published: November 2018

AbstractThe major pathway for DNA damage following hydrogen atom abstraction from the C5′‐position results in direct strand scission and concomitant formation of a 5′‐aldehyde‐containing nucleotide (e.g., T‐al). We determined that the half‐life of alkali‐labile T‐al in free DNA under physiological conditions varies from 5–12 days. T‐al reactivity was examined at three positions within nucleosome core particles (NCPs). β‐Elimination increased >2.5‐fold when T‐al was proximal to the lysine‐rich histone H4 tail. No difference in reactivity between free DNA and NCPs was observed when T‐al was distal from the histone tails. The position‐dependent involvement of histone tails in T‐al elimination was gleaned from experiments with sodium cyanoborohydride and histone protein variants. The enhancement of T‐al elimination in NCPs is significantly smaller than previously observed for abasic sites. Computational studies comparing elimination from T‐al and abasic sites indicate that the barrier for the rate‐determining step in the latter is 2.6 kcal mol−1 lower and is stabilized by a hydrogen bond between the C4‐hydroxy group and phosphate leaving group. The long lifetime for T‐al in NCPs, combined with what is known about its repair suggests that this DNA lesion might pose significant challenges within cells.