bluuebunny/crossref_metadata_2025_split huggingface dataset:
More Reliable Lithium‐Sulfur Batteries: Status, Solutions and Prospects
Authors: Fang Ruopian , Zhao Shiyong , Sun Zhenhua , Wang Da‐Wei , Cheng Hui‐Ming , Li Feng 
Published: April 2017

AbstractLithium‐sulfur (Li‐S) batteries have attracted tremendous interest because of their high theoretical energy density and cost effectiveness. The target of Li‐S battery research is to produce batteries with a high useful energy density that at least outperforms state‐of‐the‐art lithium‐ion batteries. However, due to an intrinsic gap between fundamental research and practical applications, the outstanding electrochemical results obtained in most Li‐S battery studies indeed correspond to low useful energy densities and are not really suitable for practical requirements. The Li‐S battery is a complex device and its useful energy density is determined by a number of design parameters, most of which are often ignored, leading to the failure to meet commercial requirements. The purpose of this review is to discuss how to pave the way for reliable Li‐S batteries. First, the current research status of Li‐S batteries is briefly reviewed based on statistical information obtained from literature. This includes an analysis of how the various parameters influence the useful energy density and a summary of existing problems in the current Li‐S battery research. Possible solutions and some concerns regarding the construction of reliable Li‐S batteries are comprehensively discussed. Finally, insights are offered on the future directions and prospects in Li‐S battery field.
Enantioselective Sulfa‐Michael Addition of Aromatic Thiols to β‐Substituted Nitroalkenes Promoted by a Chiral Multifunctional Catalyst
Authors: Wei Qi , Hou Wenduan , Liao Na , Peng Yungui 
Published: April 2017

AbstractAn efficient enantioselective Michael addition of a series of aromatic thiols acting as nucleophiles for β‐monosubstituted, α,β‐ and β,β‐disubstituted nitroalkenes promoted by a multi‐functional chiral catalyst has been developed. The methodology accommodates a wide variety of aryl thiols and nitroalkene substrates, and affords the 2‐nitro‐1‐arylethyl sulfides in excellent yields (up to 99%) and enantioselectivities (up to 99%ee). This reaction could be scaled up to gram even with a dramatically reduced catalyst loading of 0.05 mol%.magnified image
Exploring the Catalytic Promiscuity of Phenolic Acid Decarboxylases: Asymmetric, 1,6‐Conjugate Addition of Nucleophiles Across 4‐Hydroxystyrene
Authors: Payer Stefan E. , Sheng Xiang , Pollak Hannah , Wuensch Christiane , Steinkellner Georg , Himo Fahmi , Glueck Silvia M. , Faber Kurt 
Published: April 2017

AbstractThe catalytic promiscuity of a ferulic acid decarboxylase from Enterobacter sp. (FDC_Es) and phenolic acid decarboxylases (PADs) for the asymmetric conjugate addition of water across the C=C bond of hydroxystyrenes was extended to the N‐, C‐ and S‐nucleophiles methoxyamine, cyanide and propanethiol to furnish the corresponding addition products in up to 91% ee. The products obtained from the biotransformation employing the most suitable enzyme/nucleophile pairs were isolated and characterized after optimizing the reaction conditions. Finally, a mechanistic rationale supported by quantum mechanical calculations for the highly (S)‐selective addition of cyanide is proposed.magnified image
Synthesis of Aryldihalomethanes by Denitrogenative Dihalogenation of Benzaldehyde Hydrazones
Authors: Zhao Zhensheng , Kulkarni Kaivalya G. , Murphy Graham K. 
Published: April 2017

AbstractWe report a denitrogenative dihalogenation reaction of phenyldiazomethanes in which the hypervalent iodine reagents PhICl2 and TolIF2 act as surrogates for elemental chlorine and fluorine. Halogen transfer from iodane to aryldiazomethane is described, as is a tandem oxidative dihalogenation reaction between iodane and hydrazone. This is the first use of non‐α‐stabilized diazo compounds in this reaction, which provided an efficient synthesis of aryldifluoromethane (ArCHF2) and aryldichloromethane (ArCHCl2) derivatives.magnified image
The Diversity–Segregation Conundrum
Authors: Florida Richard 
Published: April 2017

AbstractThere is a long literature extolling the virtues of diversity for both the civility and economic performance of nations and cities. On the most basic level, diversity helps nations and cities attract the wide range of creative talent that drives innovation and economic growth. Yet similarly, there is a large amount of literature on the sorting and segregation of different types of people into distinct communities. This in turn undermines the very mixing of people and groups required for economic prosperity to flourish. This essay looks at the conundrum between diversity and segregation. It argues that both are increasingly salient, interdependent, and interconnected features of large, advanced cities or metropolitan areas. This diversity–segregation conundrum is increasingly a core feature of our social and economic landscape. It reviews several recent studies that highlight this problem, as well as some of my own very recent empirical findings on the issue.
Ethynylene‐Bridged Conjugate Carbazole Trimers: Synthesis and their Structural, Photophysical, and Electrochemical Properties
Authors: Shimasaki Toshiaki , Iwasawa Ryosuke , Watanabe Motonori , Teramoto Naozumi , Shibata Mitsuhiro 
Published: April 2017

AbstractA series of six new ethynylene‐bridged conjugate carbazole trimers (1–6) were synthesized through sequential Pd‐catalyzed Sonogashira cross‐coupling reactions. The structural properties of these trimers were examined by using DFT calculations. Compound 6, in which the two terminal carbazole moieties were substituted at the 1‐position, exhibited the longest‐wavelength UV/Vis absorption maximum in CH2Cl2, whereas compound 1, in which the two terminal carbazole moieties were substituted at the 3‐position, exhibited the shortest‐wavelength absorption maximum. These trends were rationalized by using TDDFT calculations. Electrochemical measurements and DFT calculations revealed that trimers 1–6 had smaller HOMO–LUMO gaps compared with that for the corresponding monomer (14), which was caused by a lowering of the LUMO levels, rather than by a raising of the HOMO levels. Trimers 2–6 exhibited excellent emission properties with high fluorescence quantum yields, which were derived from their rigid structures.
Applying wet sieving fecal particle size measurement to frugivores: A case study of the eastern chimpanzee (Pan troglodytes schweinfurthii)
Authors: Weary Taylor E. , Wrangham Richard W. , Clauss Marcus 
Published: April 2017

AbstractObjectivesFecal particle size (FPS) as quantified by wet sieving analysis is a measure of chewing efficiency relevant for the understanding of physiological adaptations and constraints in herbivores. FPS has not been investigated systematically in frugivores, and important methodological problems remain. In particular, food items that are not chewed may skew estimates of FPS. We address such methodological issues and also assess the influence of diet type and age on FPS in wild chimpanzees.Materials and MethodsAbout 130 fecal samples of 38 individual chimpanzees (aged from 1.3 to ∼55 years) from the Kanyawara community of Kibale National Park (Uganda) were collected during three fruit seasons and analyzed using standardized wet sieves (pores from 16 to 0.025 mm). The effects of using different sieve series and excluding large seeds were investigated. We also assessed the relationship between FPS and sex, age, and fruit season.ResultsThe treatment of seeds during the sieving process had a large influence on the results. FPS was not influenced by chimpanzee sex or age, but was smaller during a fig season (0.88 ± 0.31 mm) than during two drupe‐fruit seasons (1.68 ± 0.37 mm) (0.025–4 mm sieves, excluding seeds).DiscussionThe absence of an age effect on FPS suggests that dental senescence might be less critical in chimpanzees, or in frugivores in general, than in folivorous herbivores. To increase the value of FPS studies for understanding frugivore and hominoid dietary evolution we propose modifications to prior herbivore protocols.
Tailoring epilepsy surgery with fast ripples in the intraoperative electrocorticogram
Authors: van 't Klooster Maryse A. , van Klink Nicole E.C. , Zweiphenning Willemiek J.E.M. , Leijten Frans S.S. , Zelmann Rina , Ferrier Cyrille H. , van Rijen Peter C. , Otte Willem M. , Braun Kees P.J. , Huiskamp Geertjan J.M. , Zijlmans Maeike 
Published: April 2017

ObjectiveIntraoperative electrocorticography (ECoG) can be used to delineate the resection area in epilepsy surgery. High‐frequency oscillations (HFOs; 80–500 Hz) seem better biomarkers for epileptogenic tissue than spikes. We studied how HFOs and spikes in combined pre‐ and postresection ECoG predict surgical outcome in different tailoring approaches.MethodsWe, retrospectively, marked HFOs, divided into fast ripples (FRs; 250–500 Hz) and ripples (80–250 Hz), and spikes in pre‐ and postresection ECoG sampled at 2,048 Hz in people with refractory focal epilepsy. We defined four groups of electroencephalography (EEG) event occurrence: pre+post− (+/−), pre+post+ (+/+), pre−post+ (−/+) and pre−post− (−/−). We subcategorized three tailoring approaches: hippocampectomy with tailoring for neocortical involvement; lesionectomy of temporal lesions with tailoring for mesiotemporal involvement; and lesionectomy with tailoring for surrounding neocortical involvement. We compared the percentage of resected pre‐EEG events, time to recurrence, and the different tailoring approaches to outcome (seizure‐free vs recurrence).ResultsWe included 54 patients (median age, 15.5 years; 25 months of follow‐up; 30 seizure free). The percentage of resected FRs, ripples, or spikes in pre‐ECoG did not predict outcome. The occurrence of FRs in post‐ECoG, given FRs in pre‐ECoG (+/−, +/+), predicted outcome (hazard ratio, 3.13; confidence interval = 1.22–6.25; p = 0.01). Seven of 8 patients without spikes in pre‐ECoG were seizure free. The highest predictive value for seizure recurrence was presence of FRs in post‐ECoG for all tailoring approaches.InterpretationFRs that persist before and after resection predict poor postsurgical outcome. These findings hold for different tailoring approaches. FRs can thus be used for tailoring epilepsy surgery with repeated intraoperative ECoG measurements. Ann Neurol 2017;81:664–676
Myoclonus epilepsy and ataxia due to KCNC1 mutation: Analysis of 20 cases and K+ channel properties
Authors: Oliver Karen L. , Franceschetti Silvana , Milligan Carol J. , Muona Mikko , Mandelstam Simone A. , Canafoglia Laura , Boguszewska‐Chachulska Anna M. , Korczyn Amos D. , Bisulli Francesca , Di Bonaventura Carlo , Ragona Francesca , Michelucci Roberto , Ben‐Zeev Bruria , Straussberg Rachel , Panzica Ferruccio , Massano João , Friedman Daniel , Crespel Arielle , Engelsen Bernt A. , Andermann Frederick , Andermann Eva , Spodar Krystyna , Lasek‐Bal Anetta , Riguzzi Patrizia , Pasini Elena , Tinuper Paolo , Licchetta Laura , Gardella Elena , Lindenau Matthias , Wulf Annette , Møller Rikke S. , Benninger Felix , Afawi Zaid , Rubboli Guido , Reid Christopher A. , Maljevic Snezana , Lerche Holger , Lehesjoki Anna‐Elina , Petrou Steven , Berkovic Samuel F. 
Published: April 2017

ObjectiveTo comprehensively describe the new syndrome of myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK), including cellular electrophysiological characterization of observed clinical improvement with fever.MethodsWe analyzed clinical, electroclinical, and neuroimaging data for 20 patients with MEAK due to recurrent KCNC1 p.R320H mutation. In vitro electrophysiological studies were conducted using whole cell patch‐clamp to explore biophysical properties of wild‐type and mutant KV3.1 channels.ResultsSymptoms began at between 3 and 15 years of age (median = 9.5), with progressively severe myoclonus and rare tonic–clonic seizures. Ataxia was present early, but quickly became overshadowed by myoclonus; 10 patients were wheelchair‐bound by their late teenage years. Mild cognitive decline occurred in half. Early death was not observed. Electroencephalogram (EEG) showed generalized spike and polyspike wave discharges, with documented photosensitivity in most. Polygraphic EEG–electromyographic studies demonstrated a cortical origin for myoclonus and striking coactivation of agonist and antagonist muscles. Magnetic resonance imaging revealed symmetrical cerebellar atrophy, which appeared progressive, and a prominent corpus callosum. Unexpectedly, transient clinical improvement with fever was noted in 6 patients. To explore this, we performed high‐temperature in vitro recordings. At elevated temperatures, there was a robust leftward shift in activation of wild‐type KV3.1, increasing channel availability.InterpretationMEAK has a relatively homogeneous presentation, resembling Unverricht–Lundborg disease, despite the genetic and biological basis being quite different. A remarkable improvement with fever may be explained by the temperature‐dependent leftward shift in activation of wild‐type KV3.1 subunit–containing channels, which would counter the loss of function observed for mutant channels, highlighting KCNC1 as a potential target for precision therapeutics. Ann Neurol 2017;81:677–689
Protein Crosslinking by Genetically Encoded Noncanonical Amino Acids with Reactive Aryl Carbamate Side Chains
Authors: Xuan Weimin , Shao Sida , Schultz Peter G. 
Published: April 2017

AbstractThe use of genetically encoded noncanonical amino acids (ncAAs) to construct crosslinks within or between proteins has emerged as a useful method to enhance protein stability, investigate protein–protein interactions, and improve the pharmacological properties of proteins. We report ncAAs with aryl carbamate side chains (PheK and FPheK) that can react with proximal nucleophilic residues to form intra‐ or intermolecular protein crosslinks. We evolved a pyrrolysyl‐tRNA synthetase that incorporates site‐specifically PheK and FPheK into proteins in both E. coli and mammalian cells. PheK and FPheK when incorporated into proteins showed good stability during protein expression and purification. FPheK reacted with adjacent Lys, Cys, and Tyr residues in thioredoxin in high yields. In addition, crosslinks could be formed between FPheK and Lys residue of two interacting proteins, including the heavy chain and light chain of an antibody Fab.
Piezochromic Carbon Dots with Two‐photon Fluorescence
Authors: Lu Siyu , Xiao Guanjun , Sui Laizhi , Feng Tanglue , Yong Xue , Zhu Shoujun , Li Baojun , Liu Zhongyi , Zou Bo , Jin Mingxing , Tse John S. , Yan Hu , Yang Bai 
Published: April 2017

AbstractPiezochromic materials, which show color changes resulting from mechanical grinding or external pressure, can be used as mechanosensors, indicators of mechano‐history, security papers, optoelectronic devices, and data storage systems. A class of piezochromic materials with unprecedented two‐photon absorptive and yellow emissive carbon dots (CDs) was developed for the first time. Applied pressure from 0–22.84 GPa caused a noticeable color change in the luminescence of yellow emissive CDs, shifting from yellow (557 nm) to blue‐green (491 nm). Moreover, first‐principles calculations support transformation of the sp2 domains into sp3‐hybridized domains under high pressure. The structured CDs generated were captured by quenching the high‐pressure phase to ambient conditions, thus greatly increasing the choice of materials available for a variety of applications.
Ultrafast Independent N−H and N−C Bond Deformation Investigated with Resonant Inelastic X‐Ray Scattering
Authors: Eckert Sebastian , Norell Jesper , Miedema Piter S. , Beye Martin , Fondell Mattis , Quevedo Wilson , Kennedy Brian , Hantschmann Markus , Pietzsch Annette , Van Kuiken Benjamin E. , Ross Matthew , Minitti Michael P. , Moeller Stefan P. , Schlotter William F. , Khalil Munira , Odelius Michael , Föhlisch Alexander 
Published: April 2017

AbstractThe femtosecond excited‐state dynamics following resonant photoexcitation enable the selective deformation of N−H and N−C chemical bonds in 2‐thiopyridone in aqueous solution with optical or X‐ray pulses. In combination with multiconfigurational quantum‐chemical calculations, the orbital‐specific electronic structure and its ultrafast dynamics accessed with resonant inelastic X‐ray scattering at the N 1s level using synchrotron radiation and the soft X‐ray free‐electron laser LCLS provide direct evidence for this controlled photoinduced molecular deformation and its ultrashort timescale.
Platinum(II)‐Crosslinked Single‐Chain Nanoparticles: An Approach towards Recyclable Homogeneous Catalysts
Authors: Knöfel Nicolai D. , Rothfuss Hannah , Willenbacher Johannes , Barner‐Kowollik Christopher , Roesky Peter W. 
Published: April 2017

AbstractWe introduce the synthesis and in‐depth characterization of platinum(II)‐crosslinked single‐chain nanoparticles (PtII‐SCNPs) to demonstrate their application as a recyclable homogeneous catalyst. Specifically, a linear precursor copolymer of styrene and 4‐(diphenylphosphino)styrene was synthesized via nitroxide‐mediated polymerization. The triarylphosphine ligand moieties along the backbone allowed for the intramolecular crosslinking of single chains via the addition of [Pt(1,5‐cyclooctadiene)Cl2] in dilute solution. The successful formation of well‐defined PtII‐SCNPs was evidenced by size exclusion chromatography, dynamic light scattering, nuclear magnetic resonance (1H, 31P{1H}, 195Pt), and diffusion‐ordered spectroscopy. Finally, the activity of the PtII‐SCNPs as homogeneous, yet recyclable catalyst was successfully demonstrated using the example of the amination of allyl alcohol.
Donor Promiscuity of a Thermostable Transketolase by Directed Evolution: Efficient Complementation of 1‐Deoxy‐d‐xylulose‐5‐phosphate Synthase Activity
Authors: Saravanan Thangavelu , Junker Sebastian , Kickstein Michael , Hein Sascha , Link Marie‐Kristin , Ranglack Jan , Witt Samantha , Lorillière Marion , Hecquet Laurence , Fessner Wolf‐Dieter 
Published: April 2017

AbstractEnzymes catalyzing asymmetric carboligation reactions typically show very high substrate specificity for their nucleophilic donor substrate components. Structure‐guided engineering of the thermostable transketolase from Geobacillus stearothermophilus by directed in vitro evolution yielded new enzyme variants that are able to utilize pyruvate and higher aliphatic homologues as nucleophilic components for acyl transfer instead of the natural polyhydroxylated ketose phosphates or hydroxypyruvate. The single mutant H102T proved the best hit toward 3‐methyl‐2‐oxobutyrate as donor, while the double variant H102L/H474S showed highest catalytic efficiency toward pyruvate as donor. The latter variant was able to complement the auxotrophic deficiency of Escherichia coli cells arising from a deletion of the dxs gene, which encodes for activity of the first committed step into the terpenoid biosynthesis, offering the chance to employ a growth selection test for further enzyme optimization.
Influence of shear thinning and material flow on robotic dispensing of poly(ethylene glycol) diacrylate/poloxamer 407 hydrogels
Authors: Kraut Gabriele , Yenchesky Laura , Prieto Fermin , Tovar Günter E. M. , Southan Alexander 
Published: April 2017

ABSTRACTRobotic dispensing of hydrogels offers a direct way for generating complex hydrogel shapes. For this, there is a general need for hydrogel formulations with suitable rheological properties. In this contribution, hydrogel formulations containing poly(ethylene glycol) diacrylate (PEG‐DA) and Poloxamer 407 are characterized regarding their flow behavior during robotic dispensing. Formulations contain between 15% and 20% PEG‐DA and 22.5% and 25% Poloxamer 407. All formulations show shear thinning which can be described using a power law with a power law index between 0.10 and 0.11 and calculated shear rates at the wall of the dispensing needle of 379 s−1with a dispensing speed of 8 mm s−1and a dispensing needle inner diameter of 0.51 mm. Thus, facilitating the generation of smooth hydrogel strands, three‐dimensional hydrogel objects can be prepared without flow after robotic dispensing and can be cured afterward to elastic hydrogels, retaining the shape of the dispensed object. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2017,134, 45083.
An environmentally friendly clay‐based polymer composite “paper”
Authors: Liang Wei‐Dong , Qian Chen , Zhu Zhao‐Qi , Sun Han‐Xue , Ma Chong‐Hua , Wang Li‐Na , Wang Ran , Li An 
Published: April 2017

ABSTRACTThe paper industry is closely related to our daily life. Vast quantities of paper requirement worldwide lead to astonishing lumber consumption and environmental pollution. So the exploration of alternative paper‐like material should be of great importance. Here, we reported the preparation of a kind of environmentally friendly clay‐based polymer composite paper‐like film by incorporation of a kind of nanometer sized natural clay crystals, in this case attapulgite (ATP), into degradable poly(vinyl alcohol) (PVA) only though a simple blending and subsequently casting method. X‐ray analysis shows that no changes in the crystalline structure of ATP were observed in the PVA matrix. Even with a high content of clay crystals in composites (50 wt %), the resulting ATP‐PVA composite films (named as APCF) show excellent flexibility and tensile strength up to 22.19 MPa. The doping of ATP also results in flame retardant of composites, making it ideal candidate for packing and also building decoration applications. Interestingly, the APCF are printable and also much tough and tensile. Due to the simple fabrication, nearly no pollution emission process and easily to be scaled up, the APCF have great potentials as a kind of alternative for paper materials for diverse applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45128.
Sonochemical synthesis and stabilization of concentrated antimicrobial silver‐chitosan nanoparticle dispersions
Authors: Francesko Antonio , Cano Fossas Marta , Petkova Petya , Fernandes Margarida M. , Mendoza Ernest , Tzanov Tzanko 
Published: April 2017

ABSTRACTThis work reports on a green synthetic route to produce concentrated aqueous dispersions of silver nanoparticles (AgNP) employing high‐intensity ultrasound (US) and chitosan (CS) as a nontoxic reducing agent for Ag+ salts and AgNP stabilizer. The sonication simultaneously boosted the synthesis and improved the stability of the AgNP, capping them with CS. Hybrid AgNP‐CS antimicrobial dispersions, stable for at least 6 months, were synthesized in a simple single step process. The use of US allowed for applying relatively mild processing temperatures (60 °C) and reaction time between 30 min and 3 h to obtain concentrated dispersions of AgNP that otherwise could not be obtained even after 72 h under mechanical stirring at the same reaction conditions. Upon sonication spherical AgNP‐CS with a size between 60 and 100 nm were generated, in contrast to the average diameter of ∼200 nm of the particles obtained by stirring. The antibacterial efficiency of the AgNP‐CS hybrids was evaluated against the medically relevant pathogens Staphylococcus aureus and Escherichia coli. The US‐synthesized AgNP‐CS showed more than three fold higher antibacterial activity compared to the particles obtained under stirring, due to their higher concentration and smaller size. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45136.