bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect Of microbial Mats In The Decay Of Anurans With Implications For Understanding Taphonomic Processes In The Fossil Record
Authors: Iniesto M. , Villalba I. , Buscalioni A. D. , Guerrero M. C. , López-Archilla A. I.
Published: March 2017

The pattern and sequence of the decomposition of the Pipidae African dwarf frog (Hymenochirusboettgeri) is tracked in an experiment with microbial mats in order to explore soft tissue preservation over three years. Frog decay in microbial mats is preceded by rapid entombment (25–30 days) and mediated by the formation of a sarcophagus, which is built by a complex microbial community. The frog carcasses maintained a variety of soft tissues for years. Labile organic structures show greater durability within the mat, cells maintain their general shape (bone marrow cells and adipocytes), and muscles and connective tissues (adipose and fibrous tendons) exhibit their original organic structures. In addition, other soft tissues are promptly mineralized (day 540) in a Ca-rich carbonate phase (encephalic tectum) or enriched in sulphur residues (integumentary system). The result is coherent with a bias in soft-tissue preservation, as some tissues are more likely to be conserved than others. The outcomes support observations of exceptionally preserved fossil anurans (adults and tadpoles). Decomposition in mats shows singular conditions of pH and dissolved oxygen. Mineralization processes could be more diverse than in simple heterotrophic biofilms, opening new taphonomic processes that have yet to be explored.
Schisandrin A inhibits dengue viral replication via upregulating antiviral interferon responses through STAT signaling pathway
Authors: Yu Jung-Sheng , Wu Yu-Hsuan , Tseng Chin-Kai , Lin Chun-Kuang , Hsu Yao-Chin , Chen Yen-Hsu , Lee Jin-Ching
Published: March 2017

Dengue virus (DENV) infects 400 million people worldwide annually. Infection of more than one serotype of DENV highly corresponds to dengue hemorrhagic fever and dengue shock syndrome, which are the leading causes of high mortality. Due to lack of effective vaccines and unavailable therapies against DENV, discovery of anti-DENV agents is urgently needed. We first characterize that Schisandrin A can inhibit the replication of four serotypes of DENV in a concentration- and time-dependent manner, with an effective half-maximal effective concentration 50% (EC50) value of 28.1 ± 0.42 μM against DENV serotype type 2 without significant cytotoxicity. Furthermore, schisandrin A can effectively protect mice from DENV infection by reducing disease symptoms and mortality of DENV-infected mice. We demonstrate that STAT1/2-mediated antiviral interferon responses contribute to the action of schisandrin A against DENV replication. Schisandrin A represents a potential antiviral agent to block DENV replication in vitro and in vivo. In conclusion, stimulation of STAT1/2-mediated antiviral interferon responses is a promising strategy to develop antiviral drug.
Entropic stabilization of a deubiquitinase provides conformational plasticity and slow unfolding kinetics beneficial for functioning on the proteasome
Authors: Lee Yun-Tzai Cloud , Chang Chia-Yun , Chen Szu-Yu , Pan Yun-Ru , Ho Meng-Ru , Hsu Shang-Te Danny
Published: March 2017

Human ubiquitin C-terminal hydrolyase UCH-L5 is a topologically knotted deubiquitinase that is activated upon binding to the proteasome subunit Rpn13. The length of its intrinsically disordered cross-over loop is essential for substrate recognition. Here, we showed that the catalytic domain of UCH-L5 exhibits higher equilibrium folding stability with an unfolding rate on the scale of 10−8 s−1, over four orders of magnitudes slower than its paralogs, namely UCH-L1 and -L3, which have shorter cross-over loops. NMR relaxation dynamics analysis confirmed the intrinsic disorder of the cross-over loop. Hydrogen deuterium exchange analysis further revealed a positive correlation between the length of the cross-over loop and the degree of local fluctuations, despite UCH-L5 being thermodynamically and kinetically more stable than the shorter UCHs. Considering the role of UCH-L5 in removing K48-linked ubiquitin to prevent proteasomal degradation of ubiquitinated substrates, our findings offered mechanistic insights into the evolution of UCH-L5. Compared to its paralogs, it is entropically stabilized to withstand mechanical unfolding by the proteasome while maintaining structural plasticity. It can therefore accommodate a broad range of substrate geometries at the cost of unfavourable entropic loss.
Non-thermal air plasma promotes the healing of acute skin wounds in rats
Authors: Kubinova S. , Zaviskova K. , Uherkova L. , Zablotskii V. , Churpita O. , Lunov O. , Dejneka A.
Published: March 2017

Non-thermal plasma (NTP) has nonspecific antibacterial effects, and can be applied as an effective tool for the treatment of chronic wounds and other skin pathologies. In this study we analysed the effect of NTP on the healing of the full-thickness acute skin wound model in rats. We utilised a single jet NTP system generating atmospheric pressure air plasma, with ion volume density 5 · 1017 m−3 and gas temperature 30–35 °C. The skin wounds were exposed to three daily plasma treatments for 1 or 2 minutes and were evaluated 3, 7 and 14 days after the wounding by histological and gene expression analysis. NTP treatment significantly enhanced epithelization and wound contraction on day 7 when compared to the untreated wounds. Macrophage infiltration into the wound area was not affected by the NTP treatment. Gene expression analysis did not indicate an increased inflammatory reaction or a disruption of the wound healing process; transient enhancement of inflammatory marker upregulation was found after NTP treatment on day 7. In summary, NTP treatment had improved the healing efficacy of acute skin wounds without noticeable side effects and concomitant activation of pro-inflammatory signalling. The obtained results highlight the favourability of plasma applications for wound therapy in clinics.
Genome-wide random regression analysis for parent-of-origin effects of body composition allometries in mouse
Authors: Zhao Jingli , Li Shuling , Wang Lijuan , Jiang Li , Yang Runqing , Cui Yuehua
Published: March 2017

Genomic imprinting underlying growth and development traits has been recognized, with a focus on the form of absolute or pure growth. However, little is known about the effect of genomic imprinting on relative growth. In this study, we proposed a random regression model to estimate genome-wide imprinting effects on the relative growth of multiple tissues and organs to body weight in mice. Joint static allometry scaling equation as sub-model is nested within the genetic effects of markers and polygenic effects caused by a pedigree. Both chromosome-wide and genome-wide statistical tests were conducted to identify imprinted quantitative trait nucleotides (QTNs) associated with relative growth of individual tissues and organs to body weight. Real data analysis showed that three of six analysed tissues and organs are significantly associated with body weight in terms of phenotypic relative growth. At the chromosome-wide level, a total 122 QTNs were associated with allometries of kidney, spleen and liver weights to body weight, 36 of which were imprinted with different imprinting fashions. Further, only two imprinted QTNs responsible for relative growth of spleen and liver were verified by genome-wide test. Our approach provides a general framework for statistical inference of genomic imprinting underlying allometry scaling in animals.
Dissecting miRNA gene repression on single cell level with an advanced fluorescent reporter system
Authors: Lemus-Diaz Nicolas , Böker Kai O. , Rodriguez-Polo Ignacio , Mitter Michael , Preis Jasmin , Arlt Maximilian , Gruber Jens
Published: March 2017

Despite major advances on miRNA profiling and target predictions, functional readouts for endogenous miRNAs are limited and frequently lead to contradicting conclusions. Numerous approaches including functional high-throughput and miRISC complex evaluations suggest that the functional miRNAome differs from the predictions based on quantitative sRNA profiling. To resolve the apparent contradiction of expression versus function, we generated and applied a fluorescence reporter gene assay enabling single cell analysis. This approach integrates and adapts a mathematical model for miRNA-driven gene repression. This model predicts three distinct miRNA-groups with unique repression activities (low, mid and high) governed not just by expression levels but also by miRNA/target-binding capability. Here, we demonstrate the feasibility of the system by applying controlled concentrations of synthetic siRNAs and in parallel, altering target-binding capability on corresponding reporter-constructs. Furthermore, we compared miRNA-profiles with the modeled predictions of 29 individual candidates. We demonstrate that expression levels only partially reflect the miRNA function, fitting to the model-projected groups of different activities. Furthermore, we demonstrate that subcellular localization of miRNAs impacts functionality. Our results imply that miRNA profiling alone cannot define their repression activity. The gene regulatory function is a dynamic and complex process beyond a minimalistic conception of “highly expressed equals high repression”.
Ultrathin nickel hydroxide nanosheet arrays grafted biomass-derived honeycomb-like porous carbon with improved electrochemical performance as a supercapacitive material
Authors: Nagaraju Goli , Cha Sung Min , Yu Jae Su
Published: March 2017

Three-dimensional hierarchical honeycomb-like activated porous carbon pillared ultrathin Ni(OH)2 nanosheets (Ni(OH)2 NSs@HAPC) for use as supercapacitor materials were facilely synthesized. With an aid of pine cone flowers as a biomass source, HAPC conducting scaffolds were prepared by the alkali treatment and pyrolysis methods under an inert gas atmosphere. Subsequently, the Ni(OH)2 NSs were synthesized evenly on the surface of HAPC via a solvothermal method. The resulting HAPC and Ni(OH)2 NSs@HAPC composite materials offered free pathways for effective diffusion of electrolyte ions and fast transportation of electrons when employed as an electrode material. The Ni(OH)2 NSs@HAPC composite electrode exhibited excellent electrochemical properties including a relatively high specific capacitance (Csp) value of ~ 916.4 F/g at 1 A/g with good cycling stability compared to the pristine HAPC and Ni(OH)2 NSs electrodes. Such bio-friendly derived carbon-based materials with transition metal hydroxide/oxide composite materials could be a promising approach for high-performance energy storage devices because of their advantageous properties of cost effectiveness and easy availability.
A distinct bacterial dysbiosis associated skin inflammation in ovine footrot
Authors: Maboni Grazieli , Blanchard Adam , Frosth Sara , Stewart Ceri , Emes Richard , Tötemeyer Sabine
Published: March 2017

Ovine footrot is a highly prevalent bacterial disease caused byDichelobacter nodosusand characterised by the separation of the hoof horn from the underlying skin. The role of innate immune molecules and other bacterial communities in the development of footrot lesions remains unclear. This study shows a significant association between the high expression of IL1β and highD. nodosusload in footrot samples. Investigation of the microbial population identified distinct bacterial populations in the different disease stages and also depending on the level of inflammation.Treponema(34%),Mycoplasma(29%) andPorphyromonas(15%) were the most abundant genera associated with high levels of inflammation in footrot. In contrast,Acinetobacter(25%),Corynebacteria(17%) andFlavobacterium(17%) were the most abundant genera associated with high levels of inflammation in healthy feet. This demonstrates for the first time there is a distinct microbial community associated with footrot and high cytokine expression.
RRAM-based parallel computing architecture using k-nearest neighbor classification for pattern recognition
Authors: Jiang Yuning , Kang Jinfeng , Wang Xinan
Published: March 2017

Resistive switching memory (RRAM) is considered as one of the most promising devices for parallel computing solutions that may overcome the von Neumann bottleneck of today’s electronic systems. However, the existing RRAM-based parallel computing architectures suffer from practical problems such as device variations and extra computing circuits. In this work, we propose a novel parallel computing architecture for pattern recognition by implementing k-nearest neighbor classification on metal-oxide RRAM crossbar arrays. Metal-oxide RRAM with gradual RESET behaviors is chosen as both the storage and computing components. The proposed architecture is tested by the MNIST database. High speed (~100 ns per example) and high recognition accuracy (97.05%) are obtained. The influence of several non-ideal device properties is also discussed, and it turns out that the proposed architecture shows great tolerance to device variations. This work paves a new way to achieve RRAM-based parallel computing hardware systems with high performance.
Neurotoxicity Comparison of Two Types of Local Anaesthetics: Amide-Bupivacaine versus Ester-Procaine
Authors: Yu Xu-jiao , Zhao Wei , Li Yu-jie , Li Feng-xian , Liu Zhong-jie , Xu Hua-li , Lai Lu-ying , Xu Rui , Xu Shi-yuan
Published: March 2017

Local anaesthetics (LAs) may lead to neurological complications, but the underlying mechanism is still unclear. Many neurotoxicity research studies have examined different LAs, but none have comprehensively explored the distinct mechanisms of neurotoxicity caused by amide- (bupivacaine) and ester- (procaine) type LAs. Here, based on a CCK8 assay, LDH assay, Rhod-2-AM and JC-1 staining, 2′,7′-dichlorohy-drofluorescein diacetate and dihydroethidium probes, an alkaline comet assay, and apoptosis assay, we show that both bupivacaine and procaine significantly induce mitochondrial calcium overload and a decline in the mitochondrial membrane potential as well as overproduction of ROS, DNA damage and apoptosis (P < 0.05). There were no significant differences in mitochondrial injury and apoptosis between the bupivacaine and procaine subgroups (P > 0.05). However, to our surprise, the superoxide anionic level after treatment with bupivacaine, which leads to more severe DNA damage, was higher than the level after treatment with procaine, while procaine produced more peroxidation than bupivacaine. Some of these results were also affirmed in dorsal root ganglia neurons of C57 mice. The differences in the superoxidation and peroxidation induced by these agents suggest that different types of LAs may cause neurotoxicity via different pathways. We can target more accurate treatment based on their different mechanisms of neurotoxicity.
Morphometric analysis of sinus depth in the posterior maxilla and proposal of a novel classification
Authors: Wagner Florian , Dvorak Gabriella , Nemec Stefan , Pietschmann Peter , Traxler Hannes , Schicho Kurt , Seemann Rudolf
Published: March 2017

The aim of this study was to analyse the posterior maxillary sinus based on its extension into the alveolar process and to provide a simple clinical classification. A retrospective cohort study was conducted in CT scans of 200 dentate and 200 edentulous patients (100 women and 100 men, respectively). After manual placement of 12 reference points morphometric analysis was performed and sinus depth, residual alveolar ridge height (RH) and the sinus opening angle were calculated. Sinuses were classified according to the quartiles of sinus depth: class I (above the hard palate), class II (0–6 mm below the hard palate) and class III (>6 mm below the hard palate). Sinus depth was found to be a reliable anatomical landmark and did not vary significantly between gender (p = 0.8940) or dentition groups (p = 0.9723). Alveolar height varied significantly between sinus classes (p < 2 × 10−16) and dentition groups (p < 2 × 10−16) but not between genders (p = 0.5178). The sinus opening angle was significantly different between sinus classes (p < 2.2 × 10−16) but not between gender or dentition groups. We propose a novel classification built upon the quartiles of sinus depth, dividing the sinuses into three classes. Our classification is the first one that represents the anatomy of the patient independent of gender and dentition.
Introduction to the Biological Chemistry of Nickel
Authors: Zamble Deborah
Published: March 2017

Nickel ions are used as enzyme cofactors in organisms from all kingdoms of life, and these essential enzymes catalyze a variety of remarkable chemical reactions. A significant part of this book is devoted to updating our understanding of the biological chemistry of many of these nickel enzymes, including urease, [NiFe]-hydrogenase, carbon monoxide dehydrogenase and acetyl-CoA synthase, coenzyme M reduction, nickel superoxide dismutase, nickel utilizing glyoxylase I, and the most recent addition to this list, lactate racemase. However, as the content of this book underscores, the biology of nickel encompasses many components beyond the enzymes themselves, including multiple types of membrane transporters, metallochaperones, and regulators, which are critical for maintaining and distributing healthy levels of nickel. Moving even further out from the enzymes, a discussion of nickel in biology also includes the overlap of nickel pathways with the systems of other nutritional metals, aspects of human disease including carcinogenesis and pathogenic microorganisms, biogeochemistry, and, finally, potential applications of this information.
Nickel Toxicity and Carcinogenesis
Authors: Brocato Jason , Costa Max
Published: March 2017

Nickel is the 24th most abundant element in the earth's crust and makes up about 3% of the composition of the earth. It is the fifth most abundant element by weight after iron, oxygen, magnesium, and silicon. The metal is a well-established class I human carcinogen. In vitro mutation assays in Salmonella and mammalian cells have shown that nickel compounds have low mutagenic capabilities; therefore, its role in carcinogenesis is thought to be largely through epigenetic mechanisms. Various investigations have demonstrated nickel's ability to perturb the DNA methylome, induce changes in global histone modifications, and alter the expression of microRNAs. The changes to the epigenome observed after nickel exposure mirrors the epigenetic landscape of cancer cells. Global DNA hypomethylation and global histone hypoacetylation, two hallmark traits of cancer cells, occur after nickel exposure. Nickel also has been shown to alter the expression of several microRNAs associated with cancer. Tumor-suppressing microRNAs, those whose target mRNAs are oncogene transcripts, may be turned off after nickel treatment, while oncogenic microRNAs, those whose target mRNAs are tumor-suppressing transcripts, may be enhanced. This chapter will give a brief introduction to toxicology and epigenetics and take a deeper look into the carcinogenicity of nickel by describing several epigenetic mechanisms that mediate its carcinogenic potential.
Crystallographic Analyses of the Active Site Chemistry and Oxygen Sensitivity of [NiFe(Se)]-Hydrogenases
Authors: Volbeda A. , Fontecilla-Camps J. C.
Published: March 2017

[NiFe(Se)]-hydrogenases, well-studied enzymes capable of catalyzing the H2 ⇔ 2H+ + 2e− reaction, constitute one of a few examples of the use of catalytic nickel in biology. These enzymes have attracted considerable attention for the last couple of decades because of their potential biotechnological use in both hydrogen generation and biofuel cells. One major stumbling block for the application of many highly active [NiFe(Se)]-hydrogenases in biotechnology is their catalytic inactivation by molecular oxygen, which operates through the modification of active site cysteine thiols. In this chapter we review these reactions by describing the observed oxygen-induced modifications in several hydrogenase crystal structures solved by others and us. Taking advantage of the availability of diffraction data from the Protein Data Bank, we have revisited some of these structures and found several often overlooked minor – but possibly relevant – features common to the various enzymes. We discuss the nature of these modifications and their relationships with existing spectroscopic data. We also discuss strategies both natural, like in the case of regulatory and O2-tolerant [NiFe]-hydrogenases, and artificial, like in some of their engineered variants, that these enzymes can use to avoid oxygen-induced damage.
Nickel Regulation
Authors: Chivers Peter T.
Published: March 2017

Nickel ions are required to cofactor several microbial enzymes. Transcriptionally regulated import and export systems have evolved to control cytoplasmic nickel levels and match physiological need with metal availability. In cases where there is no physiological need, only export systems will be required. Several different regulatory mechanisms have been identified that control gene expression in response to nickel ions. These include metal-responsive transcriptional regulators, periplasmic sensors that transmit Ni status across the inner membrane, and the recently identified NiCo riboswitch, the first RNA-based Ni sensor. The abundance of structural and functional studies available for these regulators provide an understanding of how nickel ions are selectivity recognized in the complex cellular milieu. Coordination chemistries that favour stable nickel ion binding over other metal ions enable proteins to couple conformational change to the presence of the correct metal. Interestingly, Ni-import systems are regulated by proteins that use four-coordinate planar geometry while export system regulators, both protein and RNA, favour six-coordinate sites, and as a result are also responsive to cobalt ions. The protein based sensors all have tight affinities for Ni, suggesting that intracellular buffered levels are well below a single atom/compartment volume. However, this leads to the unresolved question of how nickel ions are trafficked to metalloenzyme active sites in the face of a pool of high-affinity regulatory sites.
Nickel and Virulence in Bacterial Pathogens
Authors: de Reuse Hilde
Published: March 2017

While the importance of iron during bacterial virulence is largely documented, much less is known on nickel, which is nevertheless an essential element for several bacteria. This chapter will present the few cases in which the link between nickel and bacterial virulence has been formally demonstrated. [NiFe] hydrogenase, principally, provides some pathogens an energy source in gastrointestinal niches. Urease is directly involved in pathogenicity mainly in microorganisms infecting urine and in Helicobacter pylori colonizing the stomach. Over a few years, H. pylori has become a paradigm of the relation between nickel and virulence. The mechanisms of nickel transport, trafficking, and regulation in H. pylori are presented as well as its unusual nickel binding proteins. The three nickel transporters important for the uropathogenesis of Staphylococcus aureus are described together with the recent discovery of a metallophore/nickelophore synthesis pathway involved in nickel uptake by an ABC transporter. Several reports suggest that additional virulence-related functions of nickel enzymes and novel transport mechanisms are expected to be discovered in the coming years.
Cancerous perturbations within the ERK, PI3K/Akt, and Wnt/β-catenin signaling network constitutively activate inter-pathway positive feedback loops
Authors: Padala Rahul Rao , Karnawat Rishabh , Viswanathan Satish Bharathwaj , Thakkar Abhishek Vijay , Das Asim Bikas
Published: March 2017

Perturbations in molecular signaling pathways result in a constitutively activated state, leading to malignant transformation of cells.
Synergism between non-ionic and cationic surfactants in a concentration range of mixed monolayers at an air–water interface
Authors: Bagheri Ahmad , Khalili Paresa
Published: March 2017

The mole fractions of TX100 (Xs1) and C16PC (Xs2) at the interface vs. the total surfactant concentrations in the pre-micellar region, C12, at various bulk mole fractions (y1): (●) 0.1093, (□) 0.1995, (▲) 0.2901, (+) 0.3777 (*) 0.5001 and (○) 0.5972.
Divergent unprotected peptide macrocyclisation by palladium-mediated cysteine arylation
Authors: Rojas Anthony J. , Zhang Chi , Vinogradova Ekaterina V. , Buchwald Nathan H. , Reilly John , Pentelute Bradley L. , Buchwald Stephen L.
Published: March 2017

Macrocyclic peptides are important therapeutic candidates due to their improved physicochemical properties in comparison to their linear counterparts.
Ultra-sensitive detection of protein biomarkers for diagnosis of Alzheimer’s disease
Authors: Chan Hei-Nga , Xu Di , Ho See-Lok , Wong Man Shing , Li Hung-Wing
Published: March 2017

Beta amyloid peptide, tau, and phosphorylated tau are well recognized as promising biomarkers for the diagnosis of Alzheimer’s disease (AD).
Direct Cα-heteroarylation of structurally diverse ethers via a mild N-hydroxysuccinimide mediated cross-dehydrogenative coupling reaction
Authors: Liu Shihui , Liu Aoxia , Zhang Yongqiang , Wang Wei
Published: March 2017

A new, efficient, N-hydroxysuccinimide (NHS) mediated, mild and metal-free CDC strategy for the direct Cα-heteroarylation of diverse ethers has been developed.
Amino-functionalized graphene oxide/neutral alumina nanocomposite based solid-phase extraction coupled with ion chromatography-mass spectrometry for the determination of trace haloacetic acids in drinking water
Authors: Zhong Zhixiong , Li Gongke , Shao Yijuan , Zhu Binghui , Liu Zhe , Deng Jianchao , Mo Jingtian
Published: March 2017

An efficient solid-phase extraction strategy was developed for the extraction and enrichment of ten haloacetic acids from drinking water.
Symmetry breaking during nanocrystal growth
Authors: Gilroy Kyle D. , Peng Hsin-Chieh , Yang Xuan , Ruditskiy Aleksey , Xia Younan
Published: March 2017

This article highlights the mechanisms that guide the growth of nanocrystals to asymmetric shapes based on rationally designed wet-chemical syntheses.
Hf(OTf)4-Catalyzed highly diastereoselective synthesis of 1,3-disubstituted tetralin derivatives via benzylic C(sp3)–H bond functionalization
Authors: Yoshida Taira , Mori Keiji
Published: March 2017

A highly diastereoselective synthesis of 1,3-disubstituted tetralin derivatives was achieved via Hf(OTf)4-catalyzed benzylic C(sp3)–H bond functionalization.
Anisotropic transport in 1T′ monolayer MoS2 and its metal interfaces
Authors: Saha Dipankar , Mahapatra Santanu
Published: March 2017

The investigation of crystallographic orientation dependent carrier transport in a material could lead to novel electronic devices and circuit applications. We demonstrate that, due to the clusterization of “Mo” atoms in 1T′ MoS2, the transmission along the zigzag direction is significantly higher than that in the armchair direction.
Fe atoms trapped on graphene as a potential efficient catalyst for room-temperature complete oxidation of formaldehyde: a first-principles investigation
Authors: Guo Huimin , Li Min , Liu Xin , Meng Changgong , Linguerri Roberto , Han Yu , Chambaud Gilberte
Published: March 2017

Fe atoms trapped on graphene stabilize high-spin intermediates and facilitate spin switching to keep complete oxidation of formaldehyde efficient.
Borane-catalysed postpolymerisation modification of the Si–H bonds in poly(phenylsilane)
Authors: Lee P. T. K. , Rosenberg L.
Published: March 2017

An unusually wide variety of new sidechains are introduced at a polysilane through chemoselective catalytic hydrosilation, heterodehydrocoupling, and demethanative coupling.
An integrated anti-arrhythmic target network of a Chinese medicine compound, Wenxin Keli, revealed by combined machine learning and molecular pathway analysis
Authors: Wang Taiyi , Lu Ming , Du Qunqun , Yao Xi , Zhang Peng , Chen Xiaonan , Xie Weiwei , Li Zheng , Ma Yuling , Zhu Yan
Published: March 2017

Deciphering the compound Wenxin Keli's anti-arrhythmic pharmacological mechanism by integrating network pharmacology and experimental verification methods.
Acceptorless dehydrogenation and dehydrogenative coupling of alcohols catalysed by protic NHC ruthenium complexes
Authors: Chang Weihong , Gong Xue , Wang Shuizhong , Xiao Ling-Ping , Song Guoyong
Published: March 2017

A new family of protic NHC Ru complexes can serve as efficient catalysts for acceptorless dehydrogenative transformations of alcohols.
Recent advances in positional-selective alkenylations: removable guidance for twofold C–H activation
Authors: Ma Wenbo , Gandeepan Parthasarathy , Li Jie , Ackermann Lutz
Published: March 2017

Recent advances in transition-metal catalyzed positional-selective alkenylations via twofold C–H activation directed by removable or traceless directing groups are reviewed.
Mechanically strong interpenetrating network hydrogels for differential cellular adhesion
Authors: Shen Chong , Li Yuyan , Wang Huadi , Meng Qin
Published: March 2017

Hydrogels as “soft-and-wet” materials have been widely used as tissue engineering scaffolds due to their similarity to natural extracellular matrix.
Regioselective synthesis of dipyrrolopyrazine (DPP) derivatives via metal free and metal catalyzed amination and investigation of their optical and thermal properties
Authors: Meti Puttavva , Lee Eun-Sil , Yang Jung-Won , Gong Young-Dae
Published: March 2017

Pyrazine is an important molecular scaffold employed in organic optoelectronic materials.
Pyridinium 5-aminothiazoles: specific photophysical properties and vapochromism in halogenated solvents
Authors: Yamaguchi Kirara , Murai Toshiaki , Tsuchiya Yuki , Miwa Yohei , Kutsumizu Shoichi , Sasamori Takahiro , Tokitoh Norihiro
Published: March 2017

Pyridinium-5-aminothiazoles exhibited bathochromically shifted absorption and fluorescence spectra, solvatochromism, and a reversible vapochromism specific to halogenated solvents.
Insights into the excitonic processes in polymeric photocatalysts
Authors: Wang Hui , Jiang Shenlong , Chen Shichuan , Zhang Xiaodong , Shao Wei , Sun Xianshun , Zhao Zhi , Zhang Qun , Luo Yi , Xie Yi
Published: March 2017

Photoexcitation processes of polymeric carbon nitride were systematically investigated by combining photoluminescence spectroscopy and ultrafast transient absorption spectroscopy, where the identified triplet–triplet annihilation is closely related to the quantum efficiency of photoexcitation applications.
Bioinspired stimuli-responsive multilayer film made of silk–titanate nanocomposites
Authors: Colusso Elena , Perotto Giovanni , Wang Yu , Sturaro Marco , Omenetto Fiorenzo , Martucci Alessandro
Published: March 2017

A bioinspired multilayer film made of a new silk–titanate nanocomposite material, showing a humidity-responsive behavior, has been fabricated. The multilayer structure mimics the structure of the cuticle of the Hoplia coerulea beetle and shows long-term stability over a very large relative humidity range.
The sweet side of AMPK signaling: regulation of GFAT1
Authors: Scott John W. , Oakhill Jonathan S.
Published: March 2017

Maintaining a steady balance between nutrient supply and energy demand is essential for all living organisms and is achieved through the dynamic control of metabolic processes that produce and consume adenosine-5′-triphosphate (ATP), the universal currency of energy in all cells. A key sensor of cellular energy is the adenosine-5′-monophosphate (AMP)-activated protein kinase (AMPK), which is the core component of a signaling network that regulates energy and nutrient metabolism. AMPK is activated by metabolic stresses that decrease cellular ATP, and functions to restore energy balance by orchestrating a switch in metabolism away from anabolic pathways toward energy-generating catabolic processes. A new study published in a recent issue of Biochemical Journal by Zibrova et al. shows that glutamine:fructose-6-phosphate amidotransferase-1 (GFAT1), the rate-limiting enzyme of the hexosamine biosynthesis pathway (HBP), is a physiological substrate of AMPK. The HBP is an offshoot of the glycolytic pathway that drives the synthesis of uridine-5′-diphospho-N-acetylglucosamine, the requisite donor metabolite needed for dynamic β-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) of cellular proteins. O-GlcNAcylation is a nutrient-sensitive post-translational modification that, like phosphorylation, regulates numerous intracellular processes. Zibrova et al. show that inhibitory phosphorylation of the GFAT1 residue Ser243 by AMPK in response to physiological or small-molecule activators leads to a reduction in cellular protein O-GlcNAcylation. Further work revealed that AMPK-dependent phosphorylation of GFAT1 promotes angiogenesis in endothelial cells. This elegant study demonstrates that the AMPK–GFAT1 signaling axis serves as an important communication point between two nutrient-sensitive signaling pathways and is likely to play a significant role in controlling physiological processes in many other tissues.
Maintenance of Social Anxiety in Stuttering: A Cognitive-Behavioral Model
Authors: Iverach Lisa , Rapee Ronald M. , Wong Quincy J. J. , Lowe Robyn
Published: March 2017

Purpose

Stuttering is a speech disorder frequently accompanied by anxiety in social-evaluative situations. A growing body of research has confirmed a significant rate of social anxiety disorder among adults who stutter. Social anxiety disorder is a chronic and disabling anxiety disorder associated with substantial life impairment. Several influential models have described cognitive-behavioral factors that contribute to the maintenance of social anxiety in nonstuttering populations. The purpose of the present article is to apply these leading models to the experience of social anxiety for people who stutter.

Method

Components from existing models were applied to stuttering in order to determine cognitive-behavioral processes that occur before, during, and after social-evaluative situations, which may increase the likelihood of stuttering-related social fears persisting.

Results

Maintenance of social anxiety in stuttering may be influenced by a host of interrelated factors, including fear of negative evaluation, negative social-evaluative cognitions, attentional biases, self-focused attention, safety behaviors, and anticipatory and postevent processing.

Conclusion

Given the chronic nature of social anxiety disorder, identifying factors that contribute to the persistence of stuttering-related social fears has the potential to inform clinical practice and the development of psychological treatment programs to address the speech and psychological needs of people who stutter with social anxiety.
Influence of Schottky contact on the C-V and J-V characteristics of HTM-free perovskite solar cells
Authors: Huang Y. , Aharon S. , Rolland A. , Pedesseau L. , Durand O. , Etgar L. , Even J.
Published: March 2017

The influence of the Schottky contact is studied for hole transport material (HTM) free CH3NH3PbI3 perovskite solar cells (PSCs), by using drift-diffusion and small signal models. The basic current-voltage and capacitance-voltage characteristics are simulated in reasonable agreement with experimental data. The build in potential of the finite CH3NH3PbI3 layer is extracted from a Mott-Schottky capacitance analysis. Furthermore, hole collector conductors with work-functions of more than 5.5 eV are proposed as solutions for high efficiency HTM-free CH3NH3PbI3 PSCs.
‘On Water’ Direct Aldol Reaction of Oxindoles with β,γ-Unsaturated α-Keto Esters for the Synthesis of 3-(α-Hydroxy-β-carbonyl)oxindoles
Authors: Han Man-Yi , Pan Ping , Sheng Fei-Fei
Published: March 2017

An efficient ‘on water’ direct aldol reaction of oxindoles and β,γ-unsaturated α-keto esters was developed, giving 3-(α-hydroxy-β-carbonyl)oxindoles in high yields (up to 92%) and diastereoselectivities (up to >20:1). Compared with organic solvent, water as the solvent was crucial to the reaction and rate acceleration was observed in water.
Multiple temperature sensors embedded in an ultrasonic “spiral-like” waveguide
Authors: Periyannan Suresh , Rajagopal Prabhu , Balasubramaniam Krishnan
Published: March 2017

This paper studies the propagation of ultrasound in spiral waveguides, towards distributed temperature measurements on a plane. Finite Element (FE) approach was used for understanding the velocity behaviour and consequently designing the spiral waveguide. Temperature measurements were experimentally carried out on planar surface inside a hot chamber. Transduction was performed using a piezo-electric crystal that is attached to one end of the waveguide. Lower order axisymmetric guided ultrasonic modes L(0,1) and T(0,1) were employed. Notches were introduced along the waveguide to obtain ultrasonic wave reflections. Time of fight (TOF) differences between the pre-defined reflectors (notches) located on the waveguides were used to infer local temperatures. The ultrasonic temperature measurements were compared with commercially available thermocouples.
Universal rules for visible-light absorption in hybrid perovskite materials
Authors: Kato Masato , Fujiseki Takemasa , Miyadera Tetsuhiko , Sugita Takeshi , Fujimoto Shohei , Tamakoshi Masato , Chikamatsu Masayuki , Fujiwara Hiroyuki
Published: March 2017

A variety of organic-inorganic hybrid perovskites (APbX3) consisting of mixed center cations [A = CH3NH3+, HC(NH2)2+, and Cs+] with different PbX3− cages (X = I, Br, and Cl) have been developed to realize high-efficiency solar cells. Nevertheless, clear understanding of the effects of A and X on the optical transition has been lacking. Here, we present universal rules that allow the unified interpretation of the optical absorption in various hybrid perovskites. In particular, we find that the influence of the A-site cation on the light absorption is rather significant and the absorption coefficient (α) reduces to half when CH3NH3+ is replaced with HC(NH2)2+ in the APbI3 system. Our density functional theory calculations reproduce all of the fine absorption features observed in HC(NH2)2PbI3 and CH3NH3PbBr3, allowing the unique assignment of the interband transitions in the Brillouin zone. In contrast to general understanding that the A-site cation involves weakly in the optical process, our theoretical calculations reveal that the center cation plays a critical role in the interband transition and the absorption strength in the visible region is modified by the strong A-X interaction. Furthermore, our systematic analyses show that the variation of the absorption spectrum with X can be described simply by the well-known sum rule. The universal rules established in this study explain the large reduction of α in HC(NH2)2PbI3 and predict CsPbI3 as the highest α material.
Analysis of an anti-reflecting nanowire transparent electrode for solar cells
Authors: Zhao Zhexin , Wang Ken Xingze , Fan Shanhui
Published: March 2017

Transparent electrodes are an important component in many optoelectronic devices, especially solar cells. In this paper, we investigate a nanowire transparent electrode that also functions as an anti-reflection coating for silicon solar cells, taking into account the practical constraints that the electrode is typically encapsulated and needs to be in electric contact with the semiconductor. Numerical simulations show that the electrode can provide near-perfect broadband anti-reflection over much of the frequency range above the silicon band gap for both polarizations while keeping the sheet resistance sufficiently low. To provide insights into the physics mechanism of this broadband anti-reflection, we introduce a generalized Fabry–Perot model, which captures the effects of the higher order diffraction channels as well as the modification of the reflection coefficient of the interface introduced by the nanowires. This model is validated using frequency-domain electromagnetic simulations. Our work here provides design guidelines for nanowire transparent electrode in a device configuration that is relevant for solar cell applications.
Effect of interface roughness on Auger recombination in semiconductor quantum wells
Authors: Tan Chee-Keong , Sun Wei , Wierer Jonathan J. , Tansu Nelson
Published: March 2017

Auger recombination in a semiconductor is a three-carrier process, wherein the energy from the recombination of an electron and hole pair promotes a third carrier to a higher energy state. In semiconductor quantum wells with increased carrier densities, the Auger recombination becomes an appreciable fraction of the total recombination rate and degrades luminescence efficiency. Gaining insight into the variables that influence Auger recombination in semiconductor quantum wells could lead to further advances in optoelectronic and electronic devices. Here we demonstrate the important role that interface roughness has on Auger recombination within quantum wells. Our computational studies find that as the ratio of interface roughness to quantum well thickness is increased, Auger recombination is significantly enhanced. Specifically, when considering a realistic interface roughness for an InGaN quantum well, the enhancement in Auger recombination rate over a quantum well with perfect heterointerfaces can be approximately four orders of magnitude.
Optimum orientation and tilt angle for estimating performance of photovoltaic modules in western region of Saudi Arabia
Authors: Sedraoui Khaled , Ramli Makbul A. M. , Mehedi Ibrahim M. , Hasbi Muhammad , Hiendro Ayong
Published: March 2017

This paper analyzes the optimum orientation and tilt angle effects on photovoltaic (PV) module performance in Jeddah, Saudi Arabia. This analysis will begin with the description of solar radiation and tilt angle concepts. These concepts are then used to investigate the performance of PV modules by determining the power output while varying the tilt and azimuth angles. Several azimuth and tilt angles have been analyzed for monthly, bimonthly, trimonthly, quarterly, six-monthly, and yearly periods to determine how much power output can be generated and to select the best orientation angles for the PV system. The results indicate that the highest monthly average output power of the PV is 0.225 kW, obtained in June at the 0° tilt surface of the 1-kW PV panel. However, bimonthly, trimonthly, quarterly, six-monthly, and yearly adjustments result in lower power output, with yearly adjustment giving the lowest power. Therefore, the tilt angle should always be adjusted in the shortest time possible in the interest of achieving the maximum possible power output and improving the efficiency of the PV system.
A relativistic backward-wave oscillator with frequency-selectable across X- and Ku-bands
Authors: Ge Xingjun , Li Mingzhu , He Juntao , Zhang Jun , Zhu Danni
Published: March 2017

The mechanism and realization of a relativistic backward-wave oscillator (RBWO) with frequency-selectable across X- and Ku-bands are presented. Both the transverse and the longitudinal mode selections contribute to the frequency-selectable across different bands. The transverse mode selection is achieved using the property of “surface wave” of the slow-wave structures to excite the coaxial TM01 mode (Ku-band) or the hollow TM01 mode (X-band) without exciting the higher TM modes. The longitudinal mode selection is achieved by the introduction of a coaxial extractor, which contributes to the compact structure and the restraints of the longitudinal mode competitions. In simulation, a Ku-band microwave with a frequency of 12.6 GHz and an X-band microwave with a frequency of 10.6 GHz are radiated when the inner-conductor length is 10.2 cm and 0 cm, respectively. The output power of both bands is above 2 GW. This technical route of RBWO with frequency-selectable across different bands is feasible and provide a guide to design other types of frequency tunable high power microwave sources operating at high frequency bands.
Effects of surface roughness on scratch resistance and stress-strain fields during scratch tests
Authors: Feng Biao
Published: March 2017

A three-dimensional scratch model is proposed to numerically investigate the effects of surface roughness on the scratch resistance, stress concentration, residual stress and plastic deformation during scratch tests, with the help of the finite element method. Without loss of generality, the surface roughness of a coating is modelled by a sinusoidal function. The stress and plastic strain fields with various geometry parameters of roughness are obtained and discussed. In comparison with a smooth coating, the stress concentration, the residual stress, and the scratch resistance are significantly intensified and the plastic strain is increased by a factor of five in a corrugated coating, which may tremendously reduce the material performance. Consequently, the effects of surface roughness should not be ignored in both experiments and simulations. The geometry of roughness is determined by both the wave amplitude and wavelength, and their influences on the tribological behaviors can be significant. While existing experiments are only focused on the roughness in vertical direction (corresponding to the wave amplitude), the effects of wave amplitude and wavelength can be qualitatively different in many aspects and should be considered separately. The scratch depth and the area of contact region between the indenter and coating are not very sensitive to a moderate change in the wave amplitude, while they are reduced obviously with a rising wavelength. While the stress concentration increases monotonously with a rising amplitude, it becomes more complex and the decrease of wavelength can reduce the stress concentration in some cases. A growth in roughness by a large wave amplitude or a small wavelength leads to an enhancement on scratch friction coefficient and friction resistance, which is qualitatively consistent with experiments. The findings here contribute to a new way for quantitative evaluations of the effect of surface roughness and should be beneficial to modelling and simulation in scratch tests and also to the optimum designs on the surface coating for experiments.
Influence of internal electric and elastic fields on characteristics of heterogeneous ferroelectric materials
Authors: Darinskii B. M. , Sidorkin A. S.
Published: March 2017

Dielectric properties of polycrystalline ferroelectric ceramics and ferroelectrics with compensated impurities were investigated. Electric fields at the boundaries between crystallites and the fields created by a random distribution of impurities were calculated. It was shown, that the influence of these fields leads to an increase in the effective dielectric constant and to a displacement of the phase transition temperature in these ferroelectrics to lower temperatures. These effects are associated with an asymmetric nonlinear dependence of the thermodynamic potential near to the equilibrium value of spontaneous polarization vector. The asymmetry of this dependence in the random electric and elastic fields with a zero mean value reduces the length of the spontaneous polarization vector. The polarization reduced by the indicated fields lies in a region with less curvature of the thermodynamic potential that effectively means growth the value of dielectric constant of the studied system.