bluuebunny/crossref_metadata_2025 huggingface dataset:
Epigenetic regulation of NKG2D ligands is involved in exacerbated atherosclerosis development in Sirt6 heterozygous mice
Authors: Zhang Zhu-Qin , Ren Si-Chong , Tan Ying , Li Zuo-Zhi , Tang Xiaoqiang , Wang Ting-Ting , Hao De-Long , Zhao Xiang , Chen Hou-Zao , Liu De-Pei
Published: April 2016

Sirt6 is a member of the class III histone deacetylase family which is associated with aging and longevity. Sirt6 deficient mice show an aging-like phenotype, while male transgenic mice of Sirt6 show increased longevity. Sirt6 acts as a tumor suppressor and deficiency of Sirt6 leads to cardiac hypertrophy and heart failure. Whether Sirt6 is involved in atherosclerosis development, the major cause of cardiovascular diseases, is unknown. We found that the expression of Sirt6 is lower in human atherosclerotic plaques than that in controls. When Sirt6+/−ApoE−/− and ApoE−/− mice are fed with high fat diet for 16 weeks, Sirt6+/−ApoE−/− mice show increased plaque fromation and exhibit feature of plaque instability. Furthermore, Sirt6 downregulation increases expression of NKG2D ligands, which leads to increased cytokine expression. Blocking NKG2D ligand almost completely blocks this effect. Mechanistically, Sirt6 binds to promoters of NKG2D ligand genes and regulates the H3K9 and H3K56 acetylation levels.
Pentameric quaternary structure of the intracellular domain of serotonin type 3A receptors
Authors: Pandhare Akash , Grozdanov Petar N. , Jansen Michaela
Published: April 2016

In spite of extensive efforts over decades an experimentally-derived structure of full-length eukaryotic pentameric ligand-gated ion channels (pLGICs) is still lacking. These pharmaceutically highly-relevant channels contain structurally well-conserved and characterized extracellular and transmembrane domains. The intracellular domain (ICD), however, has been orphaned in structural studies based on the consensus assumption of being largely disordered. In the present study, we demonstrate for the first time that the serotonin type 3A (5-HT3A) ICD assembles into stable pentamers in solution in the absence of the other two domains, thought to be the drivers for oligomerization. Additionally, the soluble 5-HT3A-ICD construct interacted with the protein RIC-3 (resistance to inhibitors of cholinesterase). The interaction provides evidence that the 5-HT3A-ICD is not only required but also sufficient for interaction with RIC-3. Our results suggest the ICD constitutes an oligomerization domain. This novel role significantly adds to its known contributions in receptor trafficking, targeting and functional fine-tuning. The innate diversity of the ICDs with sizes ranging from 50 to 280 amino acids indicates new methodologies need to be developed to determine the structures of these domains. The use of soluble ICD proteins that we report in the present study constitutes a useful approach to address this gap.
Detection of Volatile Organic Compounds by Self-assembled Monolayer Coated Sensor Array with Concentration-independent Fingerprints
Authors: Chang Ye , Tang Ning , Qu Hemi , Liu Jing , Zhang Daihua , Zhang Hao , Pang Wei , Duan Xuexin
Published: April 2016

In this paper, we have modeled and analyzed affinities and kinetics of volatile organic compounds (VOCs) adsorption (and desorption) on various surface chemical groups using multiple self-assembled monolayers (SAMs) functionalized film bulk acoustic resonator (FBAR) array. The high-frequency and micro-scale resonator provides improved sensitivity in the detections of VOCs at trace levels. With the study of affinities and kinetics, three concentration-independent intrinsic parameters (monolayer adsorption capacity, adsorption energy constant and desorption rate) of gas-surface interactions are obtained to contribute to a multi-parameter fingerprint library of VOC analytes. Effects of functional group’s properties on gas-surface interactions are also discussed. The proposed sensor array with concentration-independent fingerprint library shows potential as a portable electronic nose (e-nose) system for VOCs discrimination and gas-sensitive materials selections.
Observation of the Zero Doppler Effect
Authors: Ran Jia , Zhang Yewen , Chen Xiaodong , Fang Kai , Zhao Junfei , Chen Hong
Published: April 2016

The normal Doppler effect has well-established applications in many areas of science and technology. Recently, a few experimental demonstrations of the inverse Doppler effect have begun to appear in negative-index metamaterials. Here we report an experimental observation of the zero Doppler effect, that is, no frequency shift irrespective of the relative motion between the wave signal source and the detector in a zero-index metamaterial. This unique phenomenon, accompanied by the normal and inverse Doppler effects, is generated by reflecting a wave from a moving discontinuity in a composite right/left-handed transmission line loaded with varactors when operating in the near zero-index passband, or the right/left-handed passband. This work has revealed a complete picture of the Doppler effect in metamaterials and may lead to potential applications in electromagnetic wave related metrology.
Ultrasound-promoted two-step synthesis of 3-arylselenylindoles and 3-arylthioindoles as novel combretastatin A-4 analogues
Authors: Wen Zhiyong , Li Xiaona , Zuo Daiying , Lang Binyue , Wu Yang , Jiang Mingyang , Ma Huizhuo , Bao Kai , Wu Yingliang , Zhang Weige
Published: April 2016

A series of 3-(3′-hydroxy-4′-methoxyphenyl)selenyl-5,6,7-trimethoxy-1H-indoles and 3-(3′-hydroxy-4′-methoxyphenyl)thio-5,6,7-trimethoxy-1H-indoles were obtained as a new class of combretastatin A-4 (CA-4) analogues via a convenient ultrasound (US)-assisted two-step process involving 3-selenenylation/sulfenylation followed by O-deallylation. With the assistance of US irradiation, both the reaction rates and yields of selenenylation, sulfenylation and O-deallylation could be significantly improved. A comparison of the reaction rates of O-deallylation and ester reduction demonstrated that O-deallylation was more sensitive to US irradiation. Finally, these products were evaluated for their antiproliferative activities, and most of them showed moderate to potent activities against three human cancer cell lines in vitro.
Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens
Authors: Gharajehdaghipour Tazarve , Roth James D. , Fafard Paul M. , Markham John H.
Published: April 2016

Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ15N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra.
Molecular Inversion Probes for targeted resequencing in non-model organisms
Authors: Niedzicka M. , Fijarczyk A. , Dudek K. , Stuglik M. , Babik W.
Published: April 2016

Applications that require resequencing of hundreds or thousands of predefined genomic regions in numerous samples are common in studies of non-model organisms. However few approaches at the scale intermediate between multiplex PCR and sequence capture methods are available. Here we explored the utility of Molecular Inversion Probes (MIPs) for the medium-scale targeted resequencing in a non-model system. Markers targeting 112 bp of exonic sequence were designed from transcriptome of Lissotriton newts. We assessed performance of 248 MIP markers in a sample of 85 individuals. Among the 234 (94.4%) successfully amplified markers 80% had median coverage within one order of magnitude, indicating relatively uniform performance; coverage uniformity across individuals was also high. In the analysis of polymorphism and segregation within family, 77% of 248 tested MIPs were confirmed as single copy Mendelian markers. Genotyping concordance assessed using replicate samples exceeded 99%. MIP markers for targeted resequencing have a number of advantages: high specificity, high multiplexing level, low sample requirement, straightforward laboratory protocol, no need for preparation of genomic libraries and no ascertainment bias. We conclude that MIP markers provide an effective solution for resequencing targets of tens or hundreds of kb in any organism and in a large number of samples.
Adh enhances Actinobacillus pleuropneumoniae pathogenicity by binding to OR5M11 and activating p38 which induces apoptosis of PAMs and IL-8 release
Authors: Wang Lei , Qin Wanhai , Zhang Jing , Bao Chuntong , Zhang Hu , Che Yanyi , Sun Changjiang , Gu Jingmin , Feng Xin , Du Chongtao , Han Wenyu , Richard Paul Langford , Lei Liancheng
Published: April 2016

Members of the Trimeric Autotransporter Adhesin (TAA) family play a crucial role in the adhesion of Gram-negative pathogens to host cells, but the immunopathogenesis of TAAs remains unknown. Our previous studies demonstrated that Adh from Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is required for full bacterial pathogenicity. Alveolar macrophages are the first line of defense against respiratory infections. This study compared the interactions between porcine alveolar macrophages (PAMs) and wild-type A. pleuropneumoniae (5b WT) or an Adh-deletion strain (5b ΔAdh) via gene microarray, immunoprecipitation and other technologies. We found that Adh was shown to interact with the PAMs membrane protein OR5M11, an olfactory receptor, resulting in the high-level secretion of IL-8 by activation of p38 MAPK signaling pathway. Subsequently, PAMs apoptosis via the activation of the Fax and Bax signaling pathways was observed, followed by activation of caspases 8, 9, and 3. The immunological pathogenic roles of Adh were also confirmed in both murine and piglets infectious models in vivo. These results identify a novel immunological strategy for TAAs to boost the pathogenicity of A. pleuropneumoniae. Together, these datas reveal the high versatility of the Adh protein as a virulence factor and provide novel insight into the immunological pathogenic role of TAAs.
Calcium oxalate crystals increased enolase-1 secretion from renal tubular cells that subsequently enhanced crystal and monocyte invasion through renal interstitium
Authors: Chiangjong Wararat , Thongboonkerd Visith
Published: April 2016

Calcium oxalate monohydrate (COM) crystals cause kidney stone disease by still unclear mechanisms. The present study aimed to characterize changes in secretion of proteins from basolateral compartment of renal tubular epithelial cells after exposure to COM crystals and then correlated them with the stone pathogenesis. Polarized MDCK cells were cultivated in serum-free medium with or without 100 μg/ml COM crystals for 20 h. Secreted proteins collected from the lower chamber (basolateral compartment) were then resolved in 2-D gels and visualized by Deep Purple stain (n = 5 gels/group). Spot matching and intensity analysis revealed six protein spots with significantly altered levels in COM-treated samples. These proteins were then identified by tandem mass spectrometry (Q-TOF MS/MS), including enolase-1, phosphoglycerate mutase-1, actinin, 14-3-3 protein epsilon, alpha-tubulin 2 and ubiquitin-activating enzyme E1. The increased enolase-1 level was confirmed by Western blot analysis. Functional analysis revealed that enolase-1 dramatically induced COM crystal invasion through ECM migrating chamber in a dose-dependent manner. Moreover, enolase-1 bound onto U937 monocytic cell surface markedly enhanced cell migration through the ECM migrating chamber. In summary, our data indicated that the increased secretory enolase-1 induced by COM crystals played an important role in crystal invasion and inflammatory process in renal interstitium.
Advanced brain aging: relationship with epidemiologic and genetic risk factors, and overlap with Alzheimer disease atrophy patterns
Authors: Habes M , Janowitz D , Erus G , Toledo J B , Resnick S M , Doshi J , Van der Auwera S , Wittfeld K , Hegenscheid K , Hosten N , Biffar R , Homuth G , Völzke H , Grabe H J , Hoffmann W , Davatzikos C
Published: April 2016

We systematically compared structural imaging patterns of advanced brain aging (ABA) in the general-population, herein defined as significant deviation from typical BA to those found in Alzheimer disease (AD). The hypothesis that ABA would show different patterns of structural change compared with those found in AD was tested via advanced pattern analysis methods. In particular, magnetic resonance images of 2705 participants from the Study of Health in Pomerania (aged 20–90 years) were analyzed using an index that captures aging atrophy patterns (Spatial Pattern of Atrophy for Recognition of BA (SPARE-BA)), and an index previously shown to capture atrophy patterns found in clinical AD (Spatial Patterns of Abnormality for Recognition of Early Alzheimer’s Disease (SPARE-AD)). We studied the association between these indices and risk factors, including an AD polygenic risk score. Finally, we compared the ABA-associated atrophy with typical AD-like patterns. We observed that SPARE-BA had significant association with: smoking (P<0.05), anti-hypertensive (P<0.05), anti-diabetic drug use (men P<0.05, women P=0.06) and waist circumference for the male cohort (P<0.05), after adjusting for age. Subjects with ABA had spatially extensive gray matter loss in the frontal, parietal and temporal lobes (false-discovery-rate-corrected q<0.001). ABA patterns of atrophy were partially overlapping with, but notably deviating from those typically found in AD. Subjects with ABA had higher SPARE-AD values; largely due to the partial spatial overlap of associated patterns in temporal regions. The AD polygenic risk score was significantly associated with SPARE-AD but not with SPARE-BA. Our findings suggest that ABA is likely characterized by pathophysiologic mechanisms that are distinct from, or only partially overlapping with those of AD.
MAOA gene hypomethylation in panic disorder—reversibility of an epigenetic risk pattern by psychotherapy
Authors: Ziegler C , Richter J , Mahr M , Gajewska A , Schiele M A , Gehrmann A , Schmidt B , Lesch K-P , Lang T , Helbig-Lang S , Pauli P , Kircher T , Reif A , Rief W , Vossbeck-Elsebusch A N , Arolt V , Wittchen H-U , Hamm A O , Deckert J , Domschke K
Published: April 2016

Epigenetic signatures such as methylation of the monoamine oxidase A (MAOA) gene have been found to be altered in panic disorder (PD). Hypothesizing temporal plasticity of epigenetic processes as a mechanism of successful fear extinction, the present psychotherapy-epigenetic study for we believe the first time investigated MAOA methylation changes during the course of exposure-based cognitive behavioral therapy (CBT) in PD. MAOA methylation was compared between N=28 female Caucasian PD patients (discovery sample) and N=28 age- and sex-matched healthy controls via direct sequencing of sodium bisulfite-treated DNA extracted from blood cells. MAOA methylation was furthermore analyzed at baseline (T0) and after a 6-week CBT (T1) in the discovery sample parallelized by a waiting time in healthy controls, as well as in an independent sample of female PD patients (N=20). Patients exhibited lower MAOA methylation than healthy controls (P<0.001), and baseline PD severity correlated negatively with MAOA methylation (P=0.01). In the discovery sample, MAOA methylation increased up to the level of healthy controls along with CBT response (number of panic attacks; T0–T1: +3.37±2.17%), while non-responders further decreased in methylation (−2.00±1.28%; P=0.001). In the replication sample, increases in MAOA methylation correlated with agoraphobic symptom reduction after CBT (P=0.02–0.03). The present results support previous evidence for MAOA hypomethylation as a PD risk marker and suggest reversibility of MAOA hypomethylation as a potential epigenetic correlate of response to CBT. The emerging notion of epigenetic signatures as a mechanism of action of psychotherapeutic interventions may promote epigenetic patterns as biomarkers of lasting extinction effects.
Direct analysis of total tannins encapsulated in silica matrices by ultraviolet-visible diffuse reflectance spectroscopy
Authors: Santos C. , dos Santos J. H. Z.
Published: April 2016

Tannins fromAcacia mearnsiiwere encapsulated by four different sol–gel routes (acid-catalyzed hydrolytic, basic-catalyzed hydrolytic, non-hydrolytic and silica) and were quantified by diffuse reflectance spectroscopy in the ultraviolet-visible region (DRS UV-vis).
Esterification of fatty acids from waste cooking oil to biodiesel over a sulfonated resin/PVA composite
Authors: Zhang Honglei , Gao Jiarui , Zhao Zengdian , Chen George Z. , Wu Tao , He Feng
Published: April 2016

PVA enhances the catalytic activity and reusability of s-CER/PVA for esterification by absorbing the water produced and liberating reactive –SO3H sites.
Performance and design considerations for lithium excess layered oxide positive electrode materials for lithium ion batteries
Authors: Hy Sunny , Liu Haodong , Zhang Minghao , Qian Danna , Hwang Bing-Joe , Meng Ying Shirley
Published: April 2016

The Li-excess layered oxide compound is one of the most promising positive electrode materials for next generation batteries exhibiting high capacities of >300 mA h g−1 due to the unconventional participation of the oxygen anion redox in the charge compensation mechanism.
An efficient and convenient protocol for the synthesis of tetracyclic isoindolo[1,2-a]quinazoline derivatives
Authors: Madhubabu M. V. , Shankar R. , More Satish. S. , Basaveswara Rao Mandava V. , Kumar U. K. Syam , Raghunadh A.
Published: April 2016

A convenient and one-pot synthesis of tetracyclic isoindolo [1,2-a]quinazoline derivatives via Lewis acid mediated sequential C–N bond formation reactions is reported.
A polyaniline/graphene oxide nanocomposite as a voltammetric sensor for electroanalytical detection of clonazepam
Authors: Jain Rajeev , Sinha Ankita , Kumari Navneeta , Khan Ab Lateef
Published: April 2016

A voltammetric sensor based on a polyaniline/graphene oxide modified glassy carbon electrode (PANI/GRO/GCE) has been developed for the ultrasensitive voltammetric detection of clonazepam (CZPM).
Protonation of carbene-stabilized diphosphorus: complexation of HP2+
Authors: Wang Yuzhong , Hickox Hunter P. , Xie Yaoming , Wei Pingrong , Cui Dongtao , Walter Melody R. , Schaefer III Henry F. , Robinson Gregory H.
Published: April 2016

The highly reactive HP2+cation has been stabilized by carbene coordination.
Pt and Pd catalyzed oxidation of Li2O2and DMSO during Li–O2battery charging
Authors: Gittleson Forrest S. , Ryu Won-Hee , Schwab Mark , Tong Xiao , Taylor André D.
Published: April 2016

Rechargeable Li–O2and Li–air batteries require electrode and electrolyte materials that synergistically promote long-term cell operation.
A self-healing hydrogel formation strategy via exploiting endothermic interactions between polyelectrolytes
Authors: Ren Ying , Lou Ruyun , Liu Xiaocen , Gao Meng , Zheng Huizhen , Yang Ting , Xie Hongguo , Yu Weiting , Ma Xiaojun
Published: April 2016

We report a strategy to synthesize self-healing hydrogels via exploiting endothermic interactions between polyelectrolytes.
A new record excited state 3MLCT lifetime for metalorganic iron(ii) complexes
Authors: Liu Li , Duchanois Thibaut , Etienne Thibaud , Monari Antonio , Beley Marc , Assfeld Xavier , Haacke Stefan , Gros Philippe C.
Published: April 2016

The 3MLCT lifetime of iron complexes was pushed to a record lifetime of 26 ps using a new benzimidazolylidene-based C∧N∧C ligand opening up new perspectives on the way of applying such complexes to photoelectrochemical processes.
Mechanism of alkane H/D exchange over zeolite H-ZSM-5 at low temperature: a combined computational and experimental study
Authors: Chu Yueying , Xue Nianhua , Xu Bolian , Ding Qian , Feng Zhaochi , Zheng Anmin , Deng Feng
Published: April 2016

Theoretical and experimental results have provided fundamental insights into the possible pathways for the H/D exchange of isobutane with H-ZSM-5 zeolite at room temperature.
Electrochemistry at single molecule occupancy in nanopore-confined recessed ring-disk electrode arrays
Authors: Fu Kaiyu , Han Donghoon , Ma Chaoxiong , Bohn Paul W.
Published: April 2016

Electrochemical reactions at nanoscale structures possess unique characteristics, e.g. fast mass transport, high signal-to-noise ratio at low concentration, and insignificant ohmic losses even at low electrolyte concentrations. These properties motivate the fabrication of high density, laterally ordered arrays of nanopores, embedding vertically stacked metal–insulator–metal electrode structures and exhibiting precisely controlled pore size and interpore spacing for use in redox cycling. These nanoscale recessed ring-disk electrode (RRDE) arrays exhibit current amplification factors, AFRC, as large as 55-fold with Ru(NH3)62/3+, indicative of capture efficiencies at the top and bottom electrodes, Φt,b, exceeding 99%. Finite element simulations performed to investigate the concentration distribution of redox species and to assess operating characteristics are in excellent agreement with experiment. AFRC increases as the pore diameter, at constant pore spacing, increases in the range 200–500 nm and as the pore spacing, at constant pore diameter, decreases in the range 1000–460 nm. Optimized nanoscale RRDE arrays exhibit a linear current response with concentration ranging from 0.1 μM to 10 mM and a small capacitive current with scan rate up to 100 V s−1. At the lowest concentrations, the average pore occupancy is 〈n〉 ∼ 0.13 molecule establishing productive electrochemical signals at occupancies at and below the single molecule level in these nanoscale RRDE arrays.
Antiproliferative activity of bicyclic benzimidazole nucleosides: synthesis, DNA-binding and cell cycle analysis
Authors: Sontakke Vyankat A. , Lawande Pravin P. , Kate Anup N. , Khan Ayesha , Joshi Rakesh , Kumbhar Anupa A. , Shinde Vaishali S.
Published: April 2016

Bicyclic benzimidazole nucleosides were synthesized from d-glucose as a starting material. DNA binding, antiproliferative activity and cell cycle analysis were performed.
Light-driven highly efficient glycosylation reactions
Authors: Mao Run-Ze , Xiong De-Cai , Guo Fan , Li Qin , Duan Jinyou , Ye Xin-Shan
Published: April 2016

A novel and efficient light-driven glycosylation strategy was developed with wide substrate scope/generality.
Superhydrophobic copper stearate/copper oxide thin films by a simple one-step electrochemical process and their corrosion resistance properties
Authors: Xu Na , Sarkar D. K. , Grant Chen X. , Zhang Hui , Tong Weiping
Published: April 2016

Corrosion performances of superhydrophobic copper stearate/copper oxide thin films on aluminum substrates by a simple on-step electrochemical process.
Investigation of the interaction of batatasin derivatives with human serum albumin using voltammetric and spectroscopic methods
Authors: Zhu Jinhua , Hu Weiping , Wu Dandan , Chen Lanlan , Liu Xiuhua
Published: April 2016

The binding properties of batatasin derivatives with HSA were estimated by voltammetric, spectroscopic, and molecular docking methods. There were non-electroactive complexes formed between them. And the α-helix structure in HSA was reduced.
Dependence of elastic and optical properties on surface terminated groups in two-dimensional MXene monolayers: a first-principles study
Authors: Bai Yuelei , Zhou Kun , Srikanth Narasimalu , Pang John H. L. , He Xiaodong , Wang Rongguo
Published: April 2016

The low adsorption and reflectivity from infrared to ultraviolet rays account for the high transmittance of Ti3C2T2that has been experimentally observed, and it is predicted that Ti2CT2will have higher optical transmittance in this range.
Convenient synthesis of functionalized pyrrolo[3,4-b]pyridines and pyrrolo[3,4-b]quinolines via three-component reactions
Authors: Jiang Yan-Hong , Xiao Man , Yan Chao-Guo
Published: April 2016

A simple protocol for convenient construction of pyrrolo[3,4-b]pyridine skeleton was successfully developed by base promoted three-component reaction of β-enamino imide, aromatic aldehydes and malononitrile as well as its ester and amide derivatives.
Crystal strain, chemical bonding, magnetic and magnetostrictive properties of erbium (Er3+) ion substituted cobalt-rich ferrite (Co1.1Fe1.9−xErxO4)
Authors: Kakade S. G. , Kambale R. C. , Ramanna C. V. , Kolekar Y. D.
Published: April 2016

Induced strain and magnetostrictive coefficient (λ11) with the applied magnetic field (H) for different compositions of Co1.1Fe1.9−xErxO4.
Low temperature synthesis of graphene hybridized surface defective hierarchical core–shell structured ZnO hollow microspheres with long-term stable and enhanced photoelectrochemical activity
Authors: Bera Susanta , Naskar Atanu , Pal Moumita , Jana Sunirmal
Published: April 2016

Time dependent structural change (solid → core–shell → hollow) of in situ formed ZnO–graphene (ZG) microspheres by low temperature solution process and their photoelectrochemical stability.
Copper(ii)-catalyzed remote sulfonylation of aminoquinolines with sodium sulfinates via radical coupling
Authors: Xia Chengcai , Wang Kai , Xu Jun , Wei Zhenjiang , Shen Chao , Duan Guiyun , Zhu Qing , Zhang Pengfei
Published: April 2016

Many various aminoquinolines-derived sulfones were obtained in moderate to high yields via copper(ii)-catalyzed direct C(sp2)–H sulfonylation of aminoquinolines with sodium sulfinates.
Alkali metal catalyzed dehydro-coupling of boranes and amines leading to the formation of a B–N bond
Authors: Harinath A. , Anga Srinivas , Panda Tarun K.
Published: April 2016

N–H/H–B cross-dehydrogenative coupling (CDC) of boranes and amines with high conversion (>90%) and chemo-selectivity using group-1 metal salts as pre-catalysts, and under ambient conditions is presented.
Towards understanding the photocatalytic activity enhancement of ordered mesoporous Bi2MoO6 crystals prepared via a novel vacuum-assisted nanocasting method
Authors: Hao Yuchen , Dong Xiaoli , Zhai Shangru , Wang Xiuying , Ma Hongchao , Zhang Xiufang
Published: April 2016

Bi2MoO6 is an outstanding semiconductor photocatalyst and has been extensively studied; the construction of ordered mesoporous Bi2MoO6, however, remains a great challenge.
Toward environmentally compatible molecular solar cells processed from halogen-free solvents
Authors: Farahat Mahmoud E. , Tsao Cheng-Si , Huang Yu-Ching , Chang Sheng Hsiung , Budiawan Widhya , Wu Chun-Guey , Chu Chih-Wei
Published: April 2016

A PCE of greater than 7% is the highest achieved so far when using halogen-free solvents for small-molecule OPV processing.
Alginate microgels created by selective coalescence between core drops paired with an ultrathin shell
Authors: Lee Tae Yong , Praveenkumar Ramasamy , Oh You-Kwan , Lee Kyubock , Kim Shin-Hyun
Published: April 2016

A highly biocompatible microfluidic method to prepare alginate microgels is developed by selectively coalescing two distinct water drops paired with an ultra-thin oil shell.
What are male teachers’ understandings of masculinities?—an exploration of sex, gender and bodies in Irish primary schools
Authors: O'Keeffe Suzanne
Published: April 2016

Primary teaching has traditionally been framed by assumptions about gender. These commonly held, but seldom voiced, assumptions have a strong impact on male primary schoolteachers and on men considering teaching as a career. Focusing on the lives of five Irish male primary teachers, this article unpacks a number of the assumptions relating to men who teach children at primary level. Many of the assumptions are often shrouded in silence, which increases the difficulty in addressing them. In this context, discussions surrounding the topics of care, men working with young children and teaching as a feminine occupation, are presented. The study employs three data-collection phases using the interview as the primary method of enquiry. Overall, two major challenges were identified: informal barriers and the concept of care in education. The study’s findings show that gender relations within a feminine environment are central to understanding masculinities in primary schools. This article makes a contribution towards revealing how issues of masculinities are navigated and negotiated on a daily basis. Allied to this, it also provides a context for understanding the challenges male teachers face on a continuous basis. This article is published as part of a thematic collection on gender studies.
Including sheath effects in the interpretation of planar retarding potential analyzer’s low-energy ion data
Authors: Fisher L. E. , Lynch K. A. , Fernandes P. A. , Bekkeng T. A. , Moen J. , Zettergren M. , Miceli R. J. , Powell S. , Lessard M. R. , Horak P.
Published: April 2016

The interpretation of planar retarding potential analyzers (RPA) during ionospheric sounding rocket missions requires modeling the thick 3D plasma sheath. This paper overviews the theory of RPAs with an emphasis placed on the impact of the sheath on current-voltage (I-V) curves. It then describes the Petite Ion Probe (PIP) which has been designed to function in this difficult regime. The data analysis procedure for this instrument is discussed in detail. Data analysis begins by modeling the sheath with the Spacecraft Plasma Interaction System (SPIS), a particle-in-cell code. Test particles are traced through the sheath and detector to determine the detector’s response. A training set is constructed from these simulated curves for a support vector regression analysis which relates the properties of the I-V curve to the properties of the plasma. The first in situ use of the PIPs occurred during the MICA sounding rocket mission which launched from Poker Flat, Alaska in February of 2012. These data are presented as a case study, providing valuable cross-instrument comparisons. A heritage top-hat thermal ion electrostatic analyzer, called the HT, and a multi-needle Langmuir probe have been used to validate both the PIPs and the data analysis method. Compared to the HT, the PIP ion temperature measurements agree with a root-mean-square error of 0.023 eV. These two instruments agree on the parallel-to-B plasma flow velocity with a root-mean-square error of 130 m/s. The PIP with its field of view aligned perpendicular-to-B provided a density measurement with an 11% error compared to the multi-needle Langmuir Probe. Higher error in the other PIP’s density measurement is likely due to simplifications in the SPIS model geometry.
Specular optical activity of achiral metasurfaces
Authors: Plum Eric , Fedotov Vassili A. , Zheludev Nikolay I.
Published: April 2016

Optical activity in 3D-chiral media in the form of circular dichroism and birefringence is a fundamental phenomenon that serves as evidence of life forms and is widely used in spectroscopy. Even in 3D-chiral media exhibiting strong transmission optical activity, the reflective effect is weak and sometimes undetectable. Here, we report that specular optical activity at structured interfaces can be very strong. Resonant polarization rotation reaching 25° and reflectivity contrast exceeding 50% for oppositely circularly polarized waves are observed for microwaves reflected by a metasurface with structural elements lacking two-fold rotational symmetry. The effect arises at oblique incidence from a 3D-chiral arrangement of the wave's direction and the metasurface's structure that itself does not possess chiral elements. Specular optical activity of such magnitude is unprecedented. It is fundamentally different from the polarization effects occurring upon scattering, reflection, and transmission from surfaces with 2D-chiral patterns. The scale of the effect allows applications in polarization sensitive devices and surface spectroscopies.
Are there two regimes in strongly rotating turbulence?
Authors: Baqui Yasir Bin , Davidson P. A. , Ranjan Avishek
Published: April 2016

We describe numerical experiments of freely decaying, rapidly rotating turbulence in which the Rossby number varies from Ro = O(1) down to Ro ∼ 0.02. Our central premise is that there exists two distinct dynamical regimes; one for Ro > 0.3 → 0.4, which is typical of most laboratory experiments, and another corresponding to Ro < 0.3, which covers most previous numerical studies. The case of Ro > 0.3 → 0.4 is reported in Baqui and Davidson [“A phenomenological theory of rotating turbulence,” Phys. Fluids 27, 025107 (2015)] and is characterised by: (i) a growth of the parallel integral scale according to l|| ∼ l⊥Ωt; (ii) a dissipation law which is quite different from that predicted by weak-turbulence theories, specifically ε = βu3/l|| where the pre-factor β is a constant of order unity; and (iii) an inertial-range energy spectrum for both the parallel and perpendicular wavenumbers which scales as k−5/3, a scaling that has nothing to do with Kolmogorov’s law in non-rotating turbulence. (Here, l|| is the integral length-scale parallel to the rotation vector Ω, l⊥ the integral length-scale perpendicular to Ω, u the integral scale velocity, and ε the viscous dissipation rate per unit mass.) By contrast, in the low-Ro regime, we find that l|| ∼ l⊥Ωt is replaced by l|| ∼ ut and there is no power-law scaling of the inertial range energy spectrum. While the dissipation law ε = βu3/l|| continues to hold at low Ro, at least approximately, the value of β now depends on Ro. It appears, therefore, that the dynamics of these two regimes are very different, and this may help explain why experimentalists and theoreticians sometimes present rather different interpretations of rotating turbulence.
Examining k-nearest neighbour networks: Superfamily phenomena and inversion
Authors: Khor Alexander , Small Michael
Published: April 2016

We examine the use of recurrence networks in studying non-linear deterministic dynamical systems. Specifically, we focus on the case of k-nearest neighbour networks, which have already been shown to contain meaningful (and more importantly, easily accessible) information about dynamics. Superfamily phenomena have previously been identified, although a complete explanation for its appearance was not provided. Local dimension of the attractor is presented as one possible determinant, discussing the ability of specific motifs to be embedded in various dimensions. In turn, the Lyapunov spectrum provides the link between attractor dimension and dynamics required. We also prove invertibility of k-nearest neighbour networks. A new metric is provided, under which the k-nearest neighbour and ϵ-recurrence construction methods produce identical networks. Hence, the already established ϵ-recurrence inversion algorithm applies equally to the k-nearest neighbour case, and inversion is proved. The change in metric necessarily distorts the shape of the reconstructed attractor, although topology is conserved.
Semiconductor- to metallic-like behavior in Bi thin films on KCl substrate
Authors: Bui Thanh Nhan , Raskin Jean-Pierre , Hackens Benoit
Published: April 2016

Bi thin films, with a thickness of 100 nm, are deposited by electron-beam evaporation on a freshly cleaved (100) KCl substrate. The substrate temperature during film growth (Tdep) ranges from room temperature up to 170 °C. Films deposited at room temperature exhibit a maze-like microstructure typical of the rhombohedral (110) texture, as confirmed by X-ray diffraction. For Tdep above 80 °C, a different microstructure appears, characterized by concentric triangular shapes corresponding to the trigonal (111) texture. Temperature dependence of the resistivity shows a transition from a semiconductor-like behavior for films deposited at room temperature to a metallic-like behavior for Tdep above 80 °C. From magnetoresistance measurements between room temperature and 1.6 K, we extract the electron and hole mobilities, concentrations, and mean free paths, which allow to draw a complete picture of the transport properties of both types of films.
Characterization of a n+3C/n−4H SiC heterojunction diode
Authors: Minamisawa R. A. , Mihaila A. , Farkas I. , Teodorescu V. S. , Afanas'ev V. V. , Hsu C.-W. , Janzén E. , Rahimo M.
Published: April 2016

We report on the fabrication of n + 3C/n-4H SiC heterojunction diodes (HJDs) potentially promising the ultimate thermal stability of the junction. The diodes were systematically analyzed by TEM, X-ray diffraction, AFM, and secondary ion mass spectroscopy, indicating the formation of epitaxial 3C-SiC crystal on top of 4H-SiC substrate with continuous interface, low surface roughness, and up to ∼7 × 1017 cm−3 dopant impurity concentration. The conduction band off-set is about 1 V as extracted from CV measurements, while the valence bands of both SiC polytypes are aligned. The HJDs feature opening voltage of 1.65 V, consistent with the barrier height of about 1.5 eV extracted from CV measurement. We finally compare the electrical results of the n + 3C/n-4H SiC heterojunction diodes with those featuring Si and Ge doped anodes in order to evaluate current challenges involved in the fabrication of such devices.
Optical properties of Al nanostructures from time dependent density functional theory
Authors: Mokkath Junais Habeeb , Schwingenschlögl Udo
Published: April 2016

The optical properties of Al nanostructures are investigated by means of time dependent density functional theory, considering chains of varying length and ladders/stripes of varying aspect ratio. The absorption spectra show redshifting for increasing length and aspect ratio. For the chains the absorption is dominated by HOMO → LUMO transitions, whereas ladders and stripes reveal more complex spectra of plasmonic nature above a specific aspect ratio.
Polarization and angle insensitive dual-band bandpass frequency selective surface using all-dielectric metamaterials
Authors: Yu Fei , Wang Jun , Wang Jiafu , Ma Hua , Du Hongliang , Xu Zhuo , Qu Shaobo
Published: April 2016

In this paper, we demonstrate a dual-band bandpass all-dielectric frequency selective surface (FSS), the building elements of which are high-permittivity ceramic particles rather than metallic patterns. With proper structural design and parameter adjustment, the resonant frequency can be tuned at will. Dual-band bandpass response can be realized due to the coupling between electric and magnetic resonances. As an example, a dual-band bandpass FSS is designed in Ku band, which is composed of two-dimensional periodic arrays of complementary quatrefoil structures (CQS) cut from dielectric plates. Moreover, cylindrical dielectric resonators are introduced and placed in the center of each CQS to broaden the bandwidth and to sharpen the cut-off frequency. Theoretical analysis shows that the bandpass response arises from impedance matching caused by electric and magnetic resonances. In addition, effective electromagnetic parameters and dynamic field distributions are presented to explain the mechanism of impedance matching. The proposed FSS has the merits of polarization independence, stable transmission, and sharp roll-off frequency. The method can also be used to design all-dielectric FSSs with continuum structures at other frequencies.
A study of the micro- and nanoscale deformation behavior of individual austenitic dendrites in a FeCrMoVC cast alloy using micro- and nanoindentation experiments
Authors: Zeisig J. , Hufenbach J. , Wendrock H. , Gemming T. , Eckert J. , Kühn U.
Published: April 2016

Micro- and nanoindentation experiments were conducted to investigate the deformation mechanisms in a Fe79.4Cr13Mo5V1C1.6 (wt. %) cast alloy. This alloy consists of an as cast microstructure mainly composed of austenite, martensite, and a complex carbide network. During microhardness testing, metastable austenite transforms partially into martensite confirmed by electron backscatter diffraction. For nanoindentation tests, two different indenter geometries were applied (Berkovich and cube corner type). Load-displacement curves of nanoindentation in austenitic dendrites depicted pop-ins after transition into plastic deformation for both nanoindenters. Characterizations of the region beneath a nanoindent by transmission electron microscopy revealed a martensitic transformation as an activated deformation mechanism and suggest a correlation with the pop-in phenomena of the load-displacement curves. Furthermore, due to an inhomogeneous chemical composition within the austenitic dendrites, more stabilized regions deform by mechanical twinning. This additional deformation mechanism was only observed for the cube corner indenter with the sharper geometry since higher shear stresses are induced beneath the contact area.
Silver nanowires-templated metal oxide for broadband Schottky photodetector
Authors: Patel Malkeshkumar , Kim Hong-Sik , Park Hyeong-Ho , Kim Joondong
Published: April 2016

Silver nanowires (AgNWs)-templated transparent metal oxide layer was applied for Si Schottky junction device, which remarked the record fastest photoresponse of 3.4 μs. Self-operating AgNWs-templated Schottky photodetector showed broad wavelength photodetection with high responsivity (42.4 A W−1) and detectivity (2.75 × 1015 Jones). AgNWs-templated indium-tin-oxide (ITO) showed band-to-band excitation due to the internal photoemission, resulting in significant carrier collection performances. Functional metal oxide layer was formed by AgNWs-templated from ITO structure. The grown ITO above AgNWs has a cylindrical shape and acts as a thermal protector of AgNWs for high temperature environment without any deformation. We developed thermal stable AgNWs-templated transparent oxide devices and demonstrated the working mechanism of AgNWs-templated Schottky devices. We may propose the high potential of hybrid transparent layer design for various photoelectric applications, including solar cells.
Electric field control of magnetization in Cu2O/porous anodic alumina hybrid structures at room temperature
Authors: Qi L. Q. , Liu H. Y. , Sun H. Y. , Liu L. H. , Han R. S.
Published: April 2016

Cu2O nanoporous films are deposited on porous anodic alumina (PAA) substrates by DC-reactive magnetron sputtering. This paper focuses on voltage driven magnetization switching in Cu2O/PAA (CP) composite films prepared by DC-reactive magnetron sputtering. By applying a dc electric field, the magnetization of the CP composite films can be controlled in a reversible and reproducible way and shows an analogous on-off behavior. The magnitude of the change in the magnetization was about 75 emu/cm3 as the electric field was switched on and off. Resistive switching behavior was also observed in as-prepared CP composite films. Further analysis indicated that the formation/rupture of conducting filaments composed of oxygen vacancies is likely responsible for the changes in the magnetization as well as in the resistivity. Such reversible change of magnetization controlled by an electric field at room temperature may have applications in spintronics and power efficient data storage technologies.
Particle-in-cell modeling of gas-confined barrier discharge
Authors: Levko Dmitry , Raja Laxminarayan L.
Published: April 2016

Gas-confined barrier discharge is studied using the one-dimensional Particle-in-Cell Monte Carlo Collisions model for the conditions reported by Guerra-Garcia and Martinez-Sanchez [Appl. Phys. Lett. 106, 041601 (2015)]. Depending on the applied voltage, two modes of discharge are observed. In the first mode, the discharge develops in the entire interelectrode gap. In the second mode, the discharge is ignited and develops only in the gas layer having smaller breakdown voltage. The one-dimensional model shows that for the conditions considered, there is no streamer stage of breakdown as is typical for a traditional dielectric barrier discharge.
Carrier tuning the metal-insulator transition of epitaxial La0.67Sr0.33MnO3 thin film on Nb doped SrTiO3 substrate
Authors: Zhan J. M. , Li P. G. , Liu H. , Tao S. L. , Ma H. , Shen J. Q. , Pan M. J. , Zhang Z. J. , Wang S. L. , Yuan G. L.
Published: April 2016

La0.67Sr0.33MnO3 (LSMO) thin films were deposited on (001)SrTiO3(STO) and n-type doped Nb:SrTiO3(NSTO) single crystal substrates respectively. The metal to insulator transition temperature(TMI) of LSMO film on NSTO is lower than that on STO, and the TMI of LSMO can be tuned by changing the applied current in the LSMO/NSTO p-n junction. Such behaviors were considered to be related to the carrier concentration redistribution in LSMO film caused by the change of depletion layer thickness in p-n junction which depends greatly on the applied electric field. The phenomenon could be used to configure artificial devices and exploring the underlying physics.
The development of GPU-based parallel PRNG for Monte Carlo applications in CUDA Fortran
Authors: Kargaran Hamed , Minuchehr Abdolhamid , Zolfaghari Ahmad
Published: April 2016

The implementation of Monte Carlo simulation on the CUDA Fortran requires a fast random number generation with good statistical properties on GPU. In this study, a GPU-based parallel pseudo random number generator (GPPRNG) have been proposed to use in high performance computing systems. According to the type of GPU memory usage, GPU scheme is divided into two work modes including GLOBAL_MODE and SHARED_MODE. To generate parallel random numbers based on the independent sequence method, the combination of middle-square method and chaotic map along with the Xorshift PRNG have been employed. Implementation of our developed PPRNG on a single GPU showed a speedup of 150x and 470x (with respect to the speed of PRNG on a single CPU core) for GLOBAL_MODE and SHARED_MODE, respectively. To evaluate the accuracy of our developed GPPRNG, its performance was compared to that of some other commercially available PPRNGs such as MATLAB, FORTRAN and Miller-Park algorithm through employing the specific standard tests. The results of this comparison showed that the developed GPPRNG in this study can be used as a fast and accurate tool for computational science applications.
Vibration optimization of ZnO thin film bulk acoustic resonator with ring electrodes
Authors: Zhao Zinan , Qian Zhenghua , Wang Bin
Published: April 2016

A rectangular ZnO thin film bulk acoustic resonator with ring electrodes is presented in this paper to demonstrate the existence of a nearly uniform displacement distribution at the central part of this typical resonator. The variational formulation based on two-dimensional scalar differential equations provides a theoretical foundation for the Ritz method adopted in our analysis. The resonant frequencies and vibration distributions for the thickness-extensional modes of this ring electrode resonator are obtained. The structural parameters are optimized to achieve a more uniform displacement distribution and therefore a uniform mass sensitivity, which guarantee the high accuracy and repeatable measurement for sensor detection in an air or a liquid environment. These results provide a fundamental reference for the design and optimization of the high quality sensor.