bluuebunny/crossref_metadata_2025 huggingface dataset:
Long Electron–Hole Diffusion Length in High‐Quality Lead‐Free Double Perovskite Films
Authors: Ning Weihua , Wang Feng , Wu Bo , Lu Jun , Yan Zhibo , Liu Xianjie , Tao Youtian , Liu Jun‐Ming , Huang Wei , Fahlman Mats , Hultman Lars , Sum Tze Chien , Gao Feng
Published: March 2018

Developing environmentally friendly perovskites has become important in solving the toxicity issue of lead‐based perovskite solar cells. Here, the first double perovskite (Cs2AgBiBr6) solar cells using the planar structure are demonstrated. The prepared Cs2AgBiBr6 films are composed of high‐crystal‐quality grains with diameters equal to the film thickness, thus minimizing the grain boundary length and the carrier recombination. These high‐quality double perovskite films show long electron–hole diffusion lengths greater than 100 nm, enabling the fabrication of planar structure double perovskite solar cells. The resulting solar cells based on planar TiO2 exhibit an average power conversion efficiency over 1%. This work represents an important step forward toward the realization of environmentally friendly solar cells and also has important implications for the applications of double perovskites in other optoelectronic devices.
Strongly Coupled Tin‐Halide Perovskites to Modulate Light Emission: Tunable 550–640 nm Light Emission (FWHM 36–80 nm) with a Quantum Yield of up to 6.4%
Authors: Chen Min‐Yi , Lin Jin‐Tai , Hsu Chia‐Shuo , Chang Chung‐Kai , Chiu Ching‐Wen , Chen Hao Ming , Chou Pi‐Tai
Published: March 2018

Colloidal perovskite quantum dots represent one of the most promising materials for applications in solar cells and photoluminescences. These devices require a low density of crystal defects and a high yield of photogenerated carriers, which are difficult to realize in tin‐halide perovskite because of the intrinsic instability of tin during nucleation. Here, an enhancement in the luminescent property of tin‐halide perovskite nanoplates (TPNPs) that are composed of strongly coupled layered structures with the chemical formula of PEA2SnX4 (PEA = C6H5(CH2)2NH3, X = Br, I) is reported. TPNPs (X = I) show an emission at a wavelength of 640 nm, with high quantum yield of 6.40 ± 0.14% and full width at half maximum (FWHM) as small as 36 nm. The presence of aliphatic carboxylic acid is found to play a key role in reducing the tin perovskite defect density, which significantly improves the emission intensity and stability of TPNPs. Upon mixing iodo‐ and bromo‐ precursors, the emission wavelength is successfully tuned from 640 nm (PEA2SnI4) to 550 nm (PEA2SnBr4), with a corresponding emission quantum yield and FWHM of 0.16–6.40% and 36–80 nm, respectively. The results demonstrate a major advance for the emission yield and tunability of tin‐halide perovskites.
Wood‐Inspired High‐Performance Ultrathick Bulk Battery Electrodes
Authors: Lu Lei‐Lei , Lu Yu‐Yang , Xiao Zi‐Jian , Zhang Tian‐Wen , Zhou Fei , Ma Tao , Ni Yong , Yao Hong‐Bin , Yu Shu‐Hong , Cui Yi
Published: March 2018

Ultrathick electrode design is a promising strategy to enhance the specific energy of Li‐ion batteries (LIBs) without changing the underlying materials chemistry. However, the low Li‐ion conductivity caused by ultralong Li‐ion transport pathway in traditional random microstructured electrode heavily deteriorates the rate performance of ultrathick electrodes. Herein, inspired by the vertical microchannels in natural wood as the highway for water transport, the microstructures of wood are successfully duplicated into ultrathick bulk LiCoO2 (LCO) cathode via a sol–gel process to achieve the high areal capacity and excellent rate capability. The X‐ray‐based microtomography demonstrates that the uniform microchannels are built up throughout the whole wood‐templated LCO cathode bringing in 1.5 times lower of tortuosity and ≈2 times higher of Li‐ion conductivity compared to that of random structured LCO cathode. The fabricated wood‐inspired LCO cathode delivers high areal capacity up to 22.7 mAh cm−2 (five times of the existing electrode) and achieves the dynamic stress test at such high areal capacity for the first time. The reported wood‐inspired design will open a new avenue to adopt natural hierarchical structures to improve the performance of LIBs.
Responsive Block Copolymer Photonic Microspheres
Authors: Yang Yi , Kim Hodae , Xu Jiangping , Hwang Min‐Soo , Tian Di , Wang Ke , Zhang Lianbin , Liao Yonggui , Park Hong‐Gyu , Yi Gi‐Ra , Xie Xiaolin , Zhu Jintao
Published: April 2018

Responsive photonic crystals (PCs) have attracted much attention due to their broad applications in the field of chemical and physical sensing through varying optical properties when exposed to external stimuli. In particular, assembly of block copolymers (BCPs) has proven to be a robust platform for constructing PCs in the form of films or bulk. Here, the generation of BCPs photonic microspheres is presented with 3D periodical concentric lamellar structures through confined self‐assembly. The structural color of the spherical PCs can be tuned by selective swelling of one block, yielding large change of optical property through varying both layer thickness and refraction index of the domains. The as‐formed spherical PCs demonstrate large reflection wavelength shift (≈400–700 nm) under organic solvent permeation and pH adjustment. Spherical shape and structural symmetry endow the formed spherical PCs with rotation independence and monochrome, which is potentially useful in the fields of displays, sensing, and diagnostics.
Polarization Encoded Color Image Embedded in a Dielectric Metasurface
Authors: Zang Xiaofei , Dong Fengliang , Yue Fuyong , Zhang Chunmei , Xu Lihua , Song Zhiwei , Chen Ming , Chen Pai‐Yen , Buller Gerald S. , Zhu Yiming , Zhuang Songlin , Chu Weiguo , Zhang Shuang , Chen Xianzhong
Published: March 2018

Optical metasurfaces have shown unprecedented capabilities in the local manipulation of the light's phase, intensity, and polarization profiles, and represent a new viable technology for applications such as high‐density optical storage, holography and display. Here, a novel metasurface platform is demonstrated for simultaneously encoding color and intensity information into the wavelength‐dependent polarization profile of a light beam. Unlike typical metasurface devices in which images are encoded by phase or amplitude modulation, the color image here is multiplexed into several sets of polarization profiles, each corresponding to a distinct color, which further allows polarization modulation‐induced additive color mixing. This unique approach features the combination of wavelength selectivity and arbitrary polarization control down to a single subwavelength pixel level. The encoding approach for polarization and color may open a new avenue for novel, effective color display elements with fine control over both brightness and contrast, and may have significant impact for high‐density data storage, information security, and anticounterfeiting.
Synthetic Biology Makes Polymer Materials Count
Authors: Beyer Hannes M. , Engesser Raphael , Hörner Maximilian , Koschmieder Julian , Beyer Peter , Timmer Jens , Zurbriggen Matias D. , Weber Wilfried
Published: March 2018

Synthetic biology applies engineering concepts to build cellular systems that perceive and process information. This is achieved by assembling genetic modules according to engineering design principles. Recent advance in the field has contributed optogenetic switches for controlling diverse biological functions in response to light. Here, the concept is introduced to apply synthetic biology switches and design principles for the synthesis of multi‐input‐processing materials. This is exemplified by the synthesis of a materials system that counts light pulses. Guided by a quantitative mathematical model, functional synthetic biology‐derived modules are combined into a polymer framework resulting in a biohybrid materials system that releases distinct output molecules specific to the number of input light pulses detected. Further demonstration of modular extension yields a light pulse‐counting materials system to sequentially release different enzymes catalyzing a multistep biochemical reaction. The resulting smart materials systems can provide novel solutions as integrated sensors and actuators with broad perspectives in fundamental and applied research.
Direct Synthesizing In‐Plane Heterostructures of Graphene and Hexagonal Boron Nitride in Designed Pattern
Authors: Zhang Shiyu , Li Jidong , Wu Hongrong , Li Xuemei , Guo Wanlin
Published: April 2018

In‐plane heterostructure of graphene (G) and hexagonal boron nitride (h‐BN) has attracted increasing attentions owing to its exceptional properties and potentials in atomically thin circuitry. However, direct growth of patterned in‐plane G/h‐BN heterostructures (G‐BNs) by chemical vapor deposition (CVD) method in a controllable way remains a great challenge. Here, a reliable way to directly synthesize G‐BN in designed pattern by one CVD step is demonstrated. First, ultraviolet lithography and magnetron sputtering are utilized to deposit nickel nanofilm in designed pattern onto copper foil surface. Then the copper foil with prepatterned nickel nanofilm is used as the synthesis substrate. Benefiting from different mechanisms of graphene growth on Cu and Cu–Ni alloy surfaces, graphene grows solely on the Ni‐free surface of the substrate, followed by h‐BN growth on the exposed Ni‐pattern surface, realizing the direct growth of patterned G‐BN. The method presented here paves a viable road for controllable growth of 2D in‐plane heterostructures for variable applications.
Recent Advances in Halide Perovskite Photodetectors Based on Different Dimensional Materials
Authors: Wangyang Peihua , Gong Chuanhui , Rao Gaofeng , Hu Kai , Wang Xuepeng , Yan Chaoyi , Dai Liping , Wu Chunyang , Xiong Jie
Published: March 2018

Based on the understanding and control of the energy levels and density of defect states of 0D, 1D, 2D, and 3D materials, halide perovskite photodetectors (HPPDs) based on different dimensional materials have recently gained significant achievements. In addition, the detection range of HPPDs even extended from ultraviolet–visible–near infrared (UV–vis–NIR) to X/γ photons, and the self‐powered HPPDs also became a hot issue. In this review, a comprehensive summary of the recent advances in HPPDs based on different dimensional materials is proposed, including 0D, 1D, 2D, and 3D perovskite and nonperovskite (without perovskite ABX3 crystal structure) materials, focusing on the relationship among the charge‐carrier transport, operation mechanism, device architectures, and photodetecting performances. First, an introduction of composition and crystal structures of HPPDs is given, followed by the description of their key figure‐of‐merit parameters evaluation system. Next, the recent developments of HPPDs based on different dimensional materials are highlighted. And finally, the characteristics of HPPDs depending on the dimensionality are summarized, and the potential challenges and approaches for future study are also presented.
One‐Pot Synthesis of Fused N,O‐Heterocycles through Rh(III)‐Catalyzed Cascade Reactions of Aromatic/Vinylic N‐Alkoxy‐ Amides with 4‐Hydroxy‐2‐Alkynoates
Authors: Xu Yuanshuang , Li Bin , Zhang Xinying , Fan Xuesen
Published: March 2018

A highly efficient and regioselective synthesis of furo[3,4‐c]isoquinoline‐1,5(3H,4H)‐diones and furo[3,4‐b]pyridine‐2,5(1H,7H)‐diones via Rh(III)‐catalyzed one‐pot cascade reactions of aromatic/vinylic N‐alkoxyamides with 4‐hydroxy‐2‐alkynoates is presented. Mechanistically, the formation of the title compounds is triggered by a Rh(III)‐catalyzed inert C(sp2)−H bond activation of the amide substrate followed by its [4+2] annulation and lactonization with 4‐hydroxy‐2‐alkynoate featuring with an oxidizing and partially traceless directing group. To the best of our knowledge, this is the first example in which both the furan‐2(5H)‐one and the pyridin‐2(1H)‐one scaffolds are constructed in one pot under one set of reaction conditions. Compared with literature methods, notable features of this new protocol include facile formation of bis‐heterocyclic scaffolds from readily available acyclic substrates, broad substrate scope with good tolerance of a wide range of functional groups, excellent regioselectivity and high efficiency.

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Construction of All‐Carbon Quaternary Stereocenters via Asymmetric Cyclopropanations: Synthesis of Chiral Carbocyclic Pyrimidine Nucleosides
Authors: Wang Hai‐Xia , Guan Fang‐Juan , Xie Ming‐Sheng , Qu Gui‐Rong , Guo Hai‐Ming
Published: March 2018

An efficient route to synthesize chiral carbocyclic pyrimidine nucleoside analogues containing all‐carbon quaternary stereocenters has been established via the asymmetric intermolecular cyclopropanation of N1‐vinylpyrimidines and α‐aryl diazoesters. With 2 mol% of chiral dirhodium (II) carboxylate complex as the catalyst, a variety of chiral carbocyclic cytosine or uracil nucleoside analogues were obtained in good yields (up to 96% yield), high diastereoselectivities (>20:1 dr), and excellent enantioselectivities (up to 99% ee).

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Palladium‐Catalyzed Domino Dehydrogenation/Heck‐Type Reactions of Carbonyl Compounds
Authors: Le Bras Jean , Muzart Jacques
Published: March 2018

This review covers those domino reactions that involve, at least, both palladium‐catalyzed dehydrogenation of carbonyl compounds and Heck‐type reactions. While the former occurs under Pd(II) catalysis, a Pd(0) or Pd(II) catalyst is required for the latter, depending on the nature of the (hetero)arylating agent, ArX or ArH, respectively. Regeneration of the Pd(II) species is assumed to proceed by either an oxidant or the aryl halide. Proposed mechanisms are described with, in some cases, personal comments.

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Towards scale‐up of graphene production via nonoxidizing liquid exfoliation methods
Authors: Stafford Jason , Patapas Andrius , Uzo Nwachukwu , Matar Omar K. , Petit Camille
Published: March 2018

Graphene, the two‐dimensional form of carbon, has received a great deal of attention across academia and industry due to its extraordinary electrical, mechanical, thermal, chemical, and optical properties. In view of the potential impact of graphene on numerous and diverse applications in electronics, novel materials, energy, transport, and healthcare, large‐scale graphene production is a challenge that must be addressed. In the past decade, top–down production has demonstrated high potential for scale‐up. This review features the recent progress made in top–down production methods that have been proposed for the manufacturing of graphene‐based products. Fabrication methods such as liquid‐phase mechanical, chemical and electrochemical exfoliation of graphite are outlined, with a particular focus on nonoxidizing routes for graphene production. Analysis of exfoliation mechanisms, solvent considerations, key advantages and issues, and important production characteristics including production rate and yield, where applicable, are outlined. Future challenges and opportunities in graphene production are also highlighted. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3246–3276, 2018
Plastid phylogenomic analysis of green plants: A billion years of evolutionary history
Authors: Gitzendanner Matthew A. , Soltis Pamela S. , Wong Gane K.‐S. , Ruhfel Brad R. , Soltis Douglas E.
Published: March 2018

Premise of the Study

For the past one billion years, green plants (Viridiplantae) have dominated global ecosystems, yet many key branches in their evolutionary history remain poorly resolved. Using the largest analysis of Viridiplantae based on plastid genome sequences to date, we examined the phylogeny and implications for morphological evolution at key nodes.

Methods

We analyzed amino acid sequences from protein‐coding genes from complete (or nearly complete) plastomes for 1879 taxa, including representatives across all major clades of Viridiplantae. Much of the data used was derived from transcriptomes from the One Thousand Plants Project (1KP); other data were taken from GenBank.

Key Results

Our results largely agree with previous plastid‐based analyses. Noteworthy results include (1) the position of Zygnematophyceae as sister to land plants (Embryophyta), (2) a bryophyte clade (hornworts, mosses + liverworts), (3) Equisetum + Psilotaceae as sister to Marattiales + leptosporangiate ferns, (4) cycads + Ginkgo as sister to the remaining extant gymnosperms, within which Gnetophyta are placed within conifers as sister to non‐Pinaceae (Gne‐Cup hypothesis), and (5) Amborella, followed by water lilies (Nymphaeales), as successive sisters to all other extant angiosperms. Within angiosperms, there is support for Mesangiospermae, a clade that comprises magnoliids, Chloranthales, monocots, Ceratophyllum, and eudicots. The placements of Ceratophyllum and Dilleniaceae remain problematic. Within Pentapetalae, two major clades (superasterids and superrosids) are recovered.

Conclusions

This plastid data set provides an important resource for elucidating morphological evolution, dating divergence times in Viridiplantae, comparisons with emerging nuclear phylogenies, and analyses of molecular evolutionary patterns and dynamics of the plastid genome.
The thermoregulatory function of the human hand: How do palm and digit proportions affect heat loss?
Authors: Payne Stephanie , Macintosh Alison , Stock Jay
Published: March 2018

Objectives

The current study assessed whether ecogeographical patterns seen in hand proportions correlate with heat loss directly. Using a brief severe cold immersion experiment on the hand, the influence of hand and digit dimensions on heat loss was evaluated.

Materials and methods

A sample of 113 living individuals were tested. Two‐dimensional and three‐dimensional scanning techniques were used to assess hand and digit dimensions. Thermal imaging analysis was used to quantify heat loss during a 3‐min ice‐water immersion of the hands.

Results

When body size was accounted for, hand width and digit length relative to total hand length were significant predictors of heat loss from the hand.

Discussion

The current study provides empirical evidence to support the link between thermodynamic principles relating to surface area‐to‐volume ratio, and ecogeographical patterns associated with temperature.
Expanding the Chemistry of the Class C Radical SAM Methyltransferase NosN by Using an Allyl Analogue of SAM
Authors: Ji Xinjian , Mandalapu Dhanaraju , Cheng Jinduo , Ding Wei , Zhang Qi
Published: March 2018

The radical S‐adenosylmethionine (SAM) superfamily enzymes cleave SAM reductively to generate a highly reactive 5′‐deoxyadenosyl (dAdo) radical, which initiates remarkably diverse reactions. Unlike most radical SAM enzymes, the class C radical SAM methyltransferase NosN binds two SAMs in the active site, using one SAM to produce a dAdo radical and the second as a methyl donor. Here, we report a mechanistic investigation of NosN in which an allyl analogue of SAM (allyl‐SAM) was used. We show that NosN cleaves allyl‐SAM efficiently and the resulting dAdo radical can be captured by the olefin moieties of allyl‐SAM or 5′‐allylthioadenosine (ATA), the latter being a derivative of allyl‐SAM. Remarkably, we found that NosN produced two distinct sets of products in the presence and absence of the methyl acceptor substrate, thus suggesting substrate‐triggered production of ATA from allyl‐SAM. We also show that NosN produces S‐adenosylhomocysteine from 5′‐thioadenosine and homoserine lactone. These results support the idea that 5′‐methylthioadenosine is the direct methyl donor in NosN reactions, and demonstrate great potential to modulate radical SAM enzymes for novel catalytic activities.
De novo Biosynthesis of “Non‐Natural” Thaxtomin Phytotoxins
Authors: Winn Michael , Francis Daniel , Micklefield Jason
Published: March 2018

Thaxtomins are diketopiperazine phytotoxins produced by Streptomyces scabies and other actinobacterial plant pathogens that inhibit cellulose biosynthesis in plants. Due to their potent bioactivity and novel mode of action there has been considerable interest in developing thaxtomins as herbicides for crop protection. To address the need for more stable derivatives, we have developed a new approach for structural diversification of thaxtomins. Genes encoding the thaxtomin NRPS from S. scabies, along with genes encoding a promiscuous tryptophan synthase (TrpS) from Salmonella typhimurium, were assembled in a heterologous host Streptomyces albus. Upon feeding indole derivatives to the engineered S. albus strain, tryptophan intermediates with alternative substituents are biosynthesized and incorporated by the NRPS to deliver a series of thaxtomins with different functionalities in place of the nitro group. The approach described herein, demonstrates how genes from different pathways and different bacterial origins can be combined in a heterologous host to create a de novo biosynthetic pathway to “non‐natural” product target compounds.
Kupfervermittelte radikalische Polymerisation mit reversibler Deaktivierung in wässrigen Medien
Authors: Jones Glen R. , Anastasaki Athina , Whitfield Richard , Engelis Nikolaos , Liarou Evelina , Haddleton David M.
Published: March 2018

In den letzten 10 Jahren wurden wesentliche Fortschritte bei der kupfervermittelten radikalischen Polymerisation erzielt. Diese ursprüngliche Reaktion waren kaum in protischen Medien durchführbar, doch mittlerweile wurden Prozesse entwickelt, bei denen die Polymerisation vielfältiger Monomere in rein wässrigen Medien mit Katalysatormengen im ppm‐Bereich kontrolliert werden kann. Als Produkte entstehen wasserlösliche Makromoleküle eines bestimmten Molekulargewichts, einer gewünschten Architektur und chemischen Funktionalität für Anwendungen in verschiedenen Bereichen, von der Wirkstoffabgabe bis zur Erdölförderung. Hier stellen wir Synthesemethoden vor, die zur Kontrolle radikalischer Polymerisationen in Wasser unter Verwendung von Kupferkomplexen entwickelt wurden, und zeigen zukünftige Interessengebiete und noch zu bewältigende Herausforderungen auf.
Umpolung of Imines Enables Catalytic Asymmetric Regio‐reversed [3+2] Cycloadditions of Iminoesters with Nitroolefins
Authors: Feng Bin , Lu Liang‐Qiu , Chen Jia‐Rong , Feng Guoqiang , He Bin‐Qing , Lu Bin , Xiao Wen‐Jing
Published: March 2018

A copper‐catalyzed regio‐reversed asymmetric [3+2] cycloaddition of iminoesters with nitroolefins is disclosed for the first time. This method enables the facile synthesis of polysubstituted chiral pyrrolidines bearing at least one chiral quaternary center in high yields with excellent regio‐, diastereo‐, and enantioselectivity. The application of chiral P,S ligands and the unique effect of α‐aryl groups on the iminoesters are key to the success of this method. The practicality and versatility of the reaction are also demonstrated.
Polycarbonate biocomposites reinforced with a hybrid filler system of recycled carbon fiber and biocarbon: Preparation and thermomechanical characterization
Authors: Andrzejewski Jacek , Misra Manjusri , Mohanty Amar K.
Published: March 2018

In this article, we present the investigation of the use of a partly biobased hybrid reinforcement system to improve the mechanical properties of polycarbonate (PC). To minimize the amount of recycled carbon fibers (rCFs) used in this study, their initial quantity of 20% was reduced and replaced by pyrolyzed biocarbon (BC) particles in amounts of 5%, 10%, 15%, and 20%. The materials were prepared during an extrusion‐/injection‐molding processing procedure. In addition to basic mechanical tests (tensile, flexural, and Izod tests), the samples were also subjected to detailed dynamic mechanical analysis to determine the thermomechanical relationships, such as the C factor, entanglement density, adhesion factor, and reinforcing efficiency. The results confirm the positive effect of hybridization, especially for the samples with low BC contents. In relation to the 20% pure BC composites, the hybrid samples containing the same amount of mixed filler (10%; rCF10–BC10) achieved an almost triple (270%) increase in the tensile strength and a 35% increase in the modulus. The impact resistance was also increased by 170%. Differential scanning calorimetry analysis showed significant changes in the glass‐transition temperatures for the BC‐rich samples; this was due to the sensitivity of the PC matrix to the processing degradation. The application of a small quantity of epoxy‐based chain extender proved to be effective in reducing this unfavorable phenomenon. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46449.
Synthesis, spectral analysis, and catalytic activity of poly(aniline‐co‐congored)–metal oxide nanocomposites
Authors: Ponprapakaran K. , Harihara Subramani R. , Baskaran R. , Tung Kuo‐Lun , Anbarasan R.
Published: March 2018

Electrically conducting, water‐soluble fluorescent copolymer nanocomposites were synthesized by a solution polymerization method under different experimental conditions in the presence of CuO and V2O5 nanoparticles. The prepared copolymer nanocomposites were characterized with analytical tools, including Fourier transform infrared spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, and fluorescence emission spectroscopy. The order of copolymerization was determined on the basis of the UV–vis absorption spectra and fluorescence emission spectra. The copolymer–CuO nanocomposite system exhibited the highest electrical conductivity. The scanning electron microscopy image showed the presence of more CuO nanoparticles on the surface of the copolymer. Furthermore, the catalytic activity of the copolymer nanocomposites was tested for the reduction of p‐nitrophenol. All three types of polymer systems exhibited almost the same apparent rate constant values. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46469.
Influence of annealing treatment on the structure and properties of poly(4‐methyl‐1‐pentene)‐based films and membranes
Authors: Xu Liyang , Wu Gaogao , Yin Bo , Yang Ming‐bo
Published: March 2018

The poly(4‐methyl‐1‐pentene) casting films were prepared by melt extrusion and annealed below the melting temperature. The effect of annealing conditions on the structure and properties of casting films and stretched membranes was discussed. In this work, a new peak around annealing temperature, as shown in melting curves, revealed the increase in thickness of lamellar structure. Annealing treatment led to improvements of amorphous thickness and crystal orientation. And the thickness of crystal phase correlated with the logarithm of annealing time. The increase in annealing temperature or time led to the improvements of the hard elasticity of samples. Additionally, the larger porosity of stretched membranes was observed as the annealing time and temperature increased. An optimum annealing condition to prepare microporous membranes was 30 min, 200 °C. This work also discussed the importance of annealing treatment in the preparation of microporous membranes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46491.
Extraction of phenotypic traits from taxonomic descriptions for the tree of life using natural language processing
Authors: Endara Lorena , Cui Hong , Burleigh J. Gordon
Published: March 2018

Premise of the Study

Phenotypic data sets are necessary to elucidate the genealogy of life, but assembling phenotypic data for taxa across the tree of life can be technically challenging and prohibitively time consuming. We describe a semi‐automated protocol to facilitate and expedite the assembly of phenotypic character matrices of plants from formal taxonomic descriptions. This pipeline uses new natural language processing (NLP) techniques and a glossary of over 9000 botanical terms.

Methods and Results

Our protocol includes the Explorer of Taxon Concepts (ETC), an online application that assembles taxon‐by‐character matrices from taxonomic descriptions, and MatrixConverter, a Java application that enables users to evaluate and discretize the characters extracted by ETC. We demonstrate this protocol using descriptions from Araucariaceae.

Conclusions

The NLP pipeline unlocks the phenotypic data found in taxonomic descriptions and makes them usable for evolutionary analyses.
Clinical Efficacy and Safety of Baminercept, a Lymphotoxin β Receptor Fusion Protein, in Primary Sjögren's Syndrome
Authors: St.Clair E. William , Baer Alan N. , Wei Chungwen , Noaiseh Ghaith , Parke Anne , Coca Andreea , Utset Tammy O. , Genovese Mark C. , Wallace Daniel J. , McNamara James , Boyle Karen , Keyes‐Elstein Lynette , Browning Jeffrey L. , Franchimont Nathalie , Smith Kira , Guthridge Joel M. , Sanz Ignacio , James Judith A. ,   the Autoimmunity Centers of Excellence
Published: March 2018

Objective

To evaluate the clinical efficacy and safety of baminercept, a lymphotoxin β receptor IgG fusion protein (LTβR‐Ig), for the treatment of primary Sjögren's syndrome (SS), and to explore the possible mechanisms of action of this treatment.

Methods

In this multicenter trial, 52 patients with primary SS were randomized in a 2:1 ratio to receive subcutaneous injections of 100 mg of baminercept every week for 24 weeks or matching placebo. The primary end point was the change between screening and week 24 in the stimulated whole salivary flow (SWSF) rate. Secondary end points included the European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI), as well as measurements of select chemokines and cytokines and enumeration of peripheral blood B and T cell subsets.

Results

The change from baseline to week 24 in the SWSF rate was not significantly different between the baminercept and placebo treatment groups (baseline‐adjusted mean change −0.01 versus 0.07 ml/minute; P = 0.332). The change in the ESSDAI during treatment was also not significantly different between the treatment groups (baseline‐adjusted mean change −1.23 versus −0.15; P = 0.104). Although the incidence of adverse events was similar between the treatment groups, baminercept therapy was associated with a higher incidence of liver toxicity, including 2 serious adverse events. Baminercept also produced a significant decrease in plasma levels of CXCL13 and significant changes in the number of circulating B and T cells, consistent with its known inhibitory effects on LTβR signaling.

Conclusion

In this trial, treatment with baminercept failed to significantly improve glandular and extraglandular disease in patients with primary SS, despite evidence from mechanistic studies showing that it blocks LTβR signaling.
Finite‐Time H∞ Filtering for Nonlinear Continuous‐Time Singular Semi‐Markov Jump Systems
Authors: Wang Jimin , Ma Shuping , Zhang Chenghui
Published: April 2018

The stochastic finite‐time H∞ filtering issue for a class of nonlinear continuous‐time singular semi‐Markov jump systems is discussed in this paper. Firstly, sufficient conditions on singular stochastic H∞ finite‐time boundedness for the filtering error system are established. The existence of a unique solution for the corresponding system is also ensured. Secondly, based on the bounds of the time‐varying transition rate, without imposing constraints on slack variables, a novel approach to finite‐time H∞ filter design is proposed in the forms of strict LMIs, which guarantees the filtering error system is singular stochastic H∞ finite‐time bounded and of a unique solution. Compared with the existing ones, the presented results reveal less conservativeness. Finally, one numerical example is exploited to testify the advantage of the proposed design technique.
Adaptive Chattering Free Neural Network Based Sliding Mode Control for Trajectory Tracking of Redundant Parallel Manipulators
Authors: Nguyen Van‐Truong , Lin Chyi‐Yeu , Su Shun‐Feng , Tran Quoc‐Viet
Published: March 2018

In this paper, an adaptive chattering free neural network‐based sliding mode control (ACFN‐SMC) method is proposed for tracking trajectories of redundant parallel manipulators. ACFN‐SMC combines adaptive chattering free radial basis function neural networks (RBFN), sliding mode control with online updating the robust term parameters, and a nonlinear compensation item for reducing tracking errors. The stability of the closed‐loop system with modeling uncertainties, frictional uncertainties, and external disturbances is ensured by using the Lyapunov method. The proposed controller has a simple structure and little computation time while securing dynamic performance with expected quality in tracking trajectories of redundant parallel manipulators. In addition, the ACFN‐SMC strategy does not need to know the upper bound of any uncertainties. From the simulation results, it is evident that the proposed control strategy not only has significantly higher robustness capability for uncertainties but also can achieve better chattering elimination when compared with those using existing intelligent control schemes.
Getting the Message? Native Reactive Electrophiles Pass Two Out of Three Thresholds to be Bona Fide Signaling Mediators
Authors: Poganik Jesse R. , Long Marcus J. C. , Aye Yimon
Published: March 2018

Precision cell signaling activities of reactive electrophilic species (RES) are arguably among the most poorly‐understood means to transmit biological messages. Latest research implicates native RES to be a chemically‐distinct subset of endogenous redox signals that influence cell decision making through non‐enzyme‐assisted modifications of specific proteins. Yet, fundamental questions remain regarding the role of RES as bona fide second messengers. Here, we lay out three sets of criteria we feel need to be met for RES to be considered as true cellular signals that directly mediate information transfer by modifying “first‐responding” sensor proteins. We critically assess the available evidence and define the extent to which each criterion has been fulfilled. Finally, we offer some ideas on the future trajectories of the electrophile signaling field taking inspiration from work that has been done to understand canonical signaling mediators. Also see the video abstract here: https://youtu.be/rG7o0clVP0c
BET‐ting on Nrf2: How Nrf2 Signaling can Influence the Therapeutic Activities of BET Protein Inhibitors
Authors: Chatterjee Nirmalya , Bohmann Dirk
Published: March 2018

BET proteins such as Brd3 and Brd4 are chromatin‐associated factors, which control gene expression programs that promote inflammation and cancer. The Nrf2 transcription factor is a master regulator of genes that protect the organism against xenobiotic attack and oxidative stress. Nrf2 has demonstrated anti‐inflammatory activity and can support cancer cell malignancy. This review describes the discovery, mechanism and biomedical implications of the regulatory interplay between Nrf2 and BET proteins. Both Nrf2 and BET proteins are established drug targets. Small molecules that either activate or suppress these proteins are currently tested in clinical trials. The crosstalk between Nrf2 and BET proteins may have important, and until now overlooked, implications for the therapeutic effects of these drugs. Based on the information covered in this review, it should be possible to design combinatorial treatment strategies for cancer and inflammatory diseases, which may improve the efficacy of targeting a Nrf2 or BET proteins individually.
Modulator Dynamics Shape the Design Space for Stepwise‐Elution Simulated Moving Bed Chromatographic Separations
Authors: Wayne Chris J. , Velayudhan Ajoy
Published: March 2018

For proteins and other biological macromolecules, SMB chromatography is best operated non‐isocratically. However, traditional modes of non‐isocratic SMB operation generate significant mobile‐phase modulator dynamics. The mechanisms by which these modulator dynamics affect a separation's success, and thus frame the design space, have yet to be explained quantitatively. Here, the dynamics of the modulator (e.g., salts in ion exchange and hydrophobic interaction chromatography) are explicitly accounted for. This leads to the elucidation of two new design constraints, presented as dimensionless numbers, which quantify the effects of the modulator phenomena and thus predict the success of a non‐isocratic SMB separation. Consequently, these two new design constraints re‐define the SMB design space. Computational and experimental studies at the boundaries of this design space corroborate the theoretical predictions. The design of efficient and robust operating conditions through use of the new design space is also demonstrated.
Molecular determinants of the interaction of EGCG with ordered and disordered proteins
Authors: Fusco Giuliana , Sanz‐Hernandez Maximo , Ruggeri Francesco S. , Vendruscolo Michele , Dobson Christopher M. , De Simone Alfonso
Published: March 2018

The aggregation process of peptides and proteins is of great relevance as it is associated with a wide range of highly debilitating disorders, including Alzheimer's and Parkinson's diseases. The natural product (‐)‐epigallocatechin‐3‐gallate (EGCG) can redirect this process away from amyloid fibrils and towards non‐toxic oligomers. In this study we used nuclear magnetic resonance (NMR) spectroscopy to characterize the binding of EGCG to a set of natively structured and unstructured proteins. The results show that the binding process is dramatically dependent on the conformational properties of the protein involved, as EGCG interacts with different binding modes depending on the folding state of the protein. We used replica exchange molecular dynamics simulations to reproduce the trends observed in the NMR experiments, and analyzed the resulting samplings to identify the dominant direct interactions between EGCG and ordered and disordered proteins.
The importance of hippocampal dynamic connectivity in explaining memory function in multiple sclerosis
Authors: van Geest Quinten , Hulst Hanneke E. , Meijer Kim A. , Hoyng Lieke , Geurts Jeroen J.G. , Douw Linda
Published: March 2018

Introduction

Brain dynamics (i.e., variable strength of communication between areas), even at the scale of seconds, are thought to underlie complex human behavior, such as learning and memory. In multiple sclerosis (MS), memory problems occur often and have so far only been related to “stationary” brain measures (e.g., atrophy, lesions, activation and stationary (s) functional connectivity (FC) over an entire functional scanning session). However, dynamics in FC (dFC) between the hippocampus and the (neo)cortex may be another important neurobiological substrate of memory impairment in MS that has not yet been explored. Therefore, we investigated hippocampal dFC during a functional (f) magnetic resonance imaging (MRI) episodic memory task and its relationship with verbal and visuospatial memory performance outside the MR scanner.

Methods

Thirty‐eight MS patients and 29 healthy controls underwent neuropsychological tests to assess memory function. Imaging (1.5T) was obtained during performance of a memory task. We assessed hippocampal volume, functional activation, and sFC (i.e., FC of the hippocampus with the rest of the brain averaged over the entire scan, using an atlas‐based approach). Dynamic FC of the hippocampus was calculated using a sliding window approach.

Results

No group differences were found in hippocampal activation, sFC, and dFC. However, stepwise forward regression analyses in patients revealed that lower dFC of the left hippocampus (standardized β = −0.30; p = .021) could explain an additional 7% of variance (53% in total) in verbal memory, in addition to female sex and larger left hippocampal volume. For visuospatial memory, lower dFC of the right hippocampus (standardized β = −0.38; p = .013) could explain an additional 13% of variance (24% in total) in addition to higher sFC of the right hippocampus.

Conclusion

Low hippocampal dFC is an important indicator for maintained memory performance in MS, in addition to other hippocampal imaging measures. Hence, brain dynamics may offer new insights into the neurobiological mechanisms underlying memory (dys)function.
Triterpenes and Meroterpenes with Neuroprotective Effects from Ganoderma leucocontextum
Authors: Chen Hongyu , Zhang Jinjin , Ren Jinwei , Wang Wenzhao , Xiong Weiping , Zhang Yaodong , Bao Li , Liu Hongwei
Published: March 2018

Ganoderma leucocontextum is a well‐known medicinal mushroom cultivated in the Tibet Plateau of China. Chemistry investigation on the fruiting bodies of this mushroom resulted in the isolation of sixteen secondary metabolites including three new lanostane triterpenes, ganoleucoins Q – S (1 – 3), as well as thirteen known compounds (4 – 16). The structures of compounds 1 – 3 were determined by NMR, MS, CD spectral analysis, and chemical derivation method. The neuroprotective effects of compounds 1 – 16 were tested on PC12 cells. Compounds 1 and 2 showed protective effects against the H2O2 induced damage with the survival rate of 83.19 ± 0.92%, 73.37 ± 1.25% at the concentration of 200 μm, respectively. Meanwhile, compounds 1 and 2 induced neurite outgrowth at 50 – 200 μm. The results from this study suggested that G. leucocontextum and its metabolites may be potential functional food ingredients for the prevention of neurodegenerative diseases.
Vibsane‐Type Diterpenoids from Viburnum odoratissimum and Their Cytotoxic and HSP90 Inhibitory Activities
Authors: Zhu Qin‐Feng , Qi Yan‐Yan , Zhang Zhi‐Jun , Fan Min , Bi Ran , Su Jia , Wu Xing‐De , Shao Li‐Dong , Zhao Qin‐Shi
Published: March 2018

Four new vibsane‐type diterpenoids, vibsanol I (1), 15‐hydroperoxyvibsanol A (2), 14‐hydroperoxyvibsanol B (3), 15‐O‐methylvibsanin U (4), and a new natural product, 5,6‐dihydrovibsanin B (5), as well as six known analogues, were isolated from the twigs and leaves of Viburnum odoratissimum. Their structures were elucidated by spectroscopic analyses and chemical derivatization method. All compounds showed different levels of cytotoxicity against five cell lines (HL‐60, A‐549, SMMC‐7721, MCF‐7, and SW480). Remarkably, 14,18‐O‐diacetyl‐15‐O‐methylvibsanin U (4a) showed significant cytotoxicity against HL‐60, A‐549, SMMC‐7721, MCF‐7, and SW480, with IC50 values of 0.15 ± 0.01, 0.69 ± 0.01, 0.41 ± 0.02, 0.75 ± 0.03, and 0.48 ± 0.03 μm, respectively. In addition, vibsanin K (10) was identified as a HSP90 inhibitor with an IC50 value of 19.16 μm.
Variation in Phenolic Content, Profile, and Antioxidant Activity of Seeds among Different Paeonia ostii Cultivated Populations in China
Authors: Zhang Xiao‐Xiao , Zhang Gang , Jin Min , Niu Li‐Xin , Zhang Yan‐Long
Published: March 2018

The purpose of this study was to analyze the phenolic profiles of seeds from fifteen Paeonia ostii cultivated populations in China and identify their relationship with antioxidant activities and associated environmental factors. Thirteen individual phenolic compounds were quantitatively determined by HPLC, and (+)‐catechin was the most abundant phenolic compound in the seeds. Correlation analysis showed that phenolics were the most effective antioxidant compound class by evaluating DPPH, ABTS, and hydroxyl radical scavenging activities as well as ferric reducing antioxidant power. Latitude and annual rainfall had significant effects on the contents of many phenolic compounds, and elevation was only significantly correlated with gallic acid content. Within fifteen P. ostii cultivated populations, the seeds of Tongling population exhibited the highest phenolic contents and strongest antioxidant activities. These results suggest that Tongling population has a relatively high utilization value and a potential for sources of natural antioxidants.
Changes in color and carotenoids of sweet corn juice during high‐temperature heating
Authors: Song Jiangfeng , Meng Lili , Liu Chunquan , Li Dajing , Zhang Min
Published: April 2018

Background and objectives

Changes in color and carotenoid content of sweet corn juice due to thermal treatment were studied. The visual color was assessed using the CIELAB system, and predominant carotenoids were identified by the C30‐HPLC‐APCI‐MS technique.

Findings

The color L* and b* values were overall decreased, while ΔE value increased to some extent during heating treatment. First‐order kinetic models were well applied to describe carotenoid changes with activation energies of 12.34–17.66 kJ/mol. Several carotenoids showed important changes and had different susceptibilities to high temperature. According to the principal component analysis, PC1 was associated with lutein, zeaxanthin, and α‐cryptoxanthin contents and PC2 with L*×b*/a* value. Limited degradation of carotenoids in juice system led to an imperceptible color change. However, the color L* value was a good indicator monitoring the changes in zeaxanthin and lutein of sweet corn juice.

Conclusions

There was a good relationship between visual color L* value and dominant zeaxanthin/lutein content in sweet corn juice during thermal processing, suggesting the suitability of the visual color parameter in place of carotenoid content for online quality control.

Significance and novelty

Although limited degradation of carotenoids in sweet corn juice system led to an imperceptible color change, the color L* value could be applied for monitoring the changes in zeaxanthin and lutein.
Computational Insights into the Gold‐Catalyzed Ring‐Opening of Methylenecyclopropanes and Vinylcyclopropanes with Sulfonamides
Authors: Liu Yuan , Feng Sidi , Bao Xiaoguang
Published: March 2018

Computational studies were carried out to investigate the mechanisms of gold‐catalyzed ring‐opening of methylenecyclopropanes (MCPs) and vinylcyclopropanes (VCPs), respectively, with sulfonamides to afford homoallylic amine intermediates, which would subsequently produce pyrrolidine derivatives. The detailed activation modes of MCPs mediated by the AuI catalyst were comprehensively explored. Computational results suggested that the activation of MCP by the AuI catalyst was less feasible. Instead, the AuI catalyst mediated activation of sulfonamides could result in the increased acidity of the N−H bond, which is ready to undergo intermolecular proton transfer to the C=C moiety of MCP to form a cyclopropylcarbinyl cation intermediate. Subsequently, the nucleophilic attack of the formed amido group to the three‐membered ring moiety of the yielded cyclopropylcarbinyl cation intermediate in an SN2 manner could follow to afford the ring‐opening homoallylic sulfonamide. In addition, computational studies indicated that such mechanistic pathway could also apply to the VCPs involved hydroamination with sulfonamides. The mechanism of triflic acid catalyzed hydroamination of MCPs and VCPs with sulfonamides also proceeds via the cyclopropylcarbinyl cation intermediates formed by the protonation of the alkene moiety of MCPs and VCPs, respectively. The ineffectiveness of amines as aminating reagents in the AuI‐catalyzed hydroamination of MCPs and VCPs was discussed.
Silica Metal Oxide Vesicles Catalyze Comprehensive Prebiotic Chemistry
Authors: Mattia Bizzarri Bruno , Botta Lorenzo , Pérez‐Valverde Maritza Iveth , Saladino Raffaele , Di Mauro Ernesto , García‐Ruiz Juan Manuel
Published: March 2018

It has recently been demonstrated that mineral self‐assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth‐like planets. We have synthesized self‐assembled membranes by mixing microdrops of metal solutions with alkaline silicate solutions in the presence of formamide (NH2CHO), a single‐carbon molecule, at 80 °C. We found that these bilayer membranes, made of amorphous silica and metal oxide/hydroxide nanocrystals, catalyze the condensation of formamide, yielding the four nucleobases of RNA, three amino acids and, several carboxylic acids in a single‐pot experiment. Besides manganese, iron and magnesium, two abundant elements in the earliest Earth crust that are key in serpentinization reactions, are enough to produce all these biochemical compounds. These results suggest that the transition from inorganic geochemistry to prebiotic organic chemistry is common on a universal scale and, most probably, occurred earlier than ever thought for our planet.