bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of temperature-dependent photoluminescence in multi-quantum wells
Authors: Fang Yutao , Wang Lu , Sun Qingling , Lu Taiping , Deng Zhen , Ma Ziguang , Jiang Yang , Jia Haiqiang , Wang Wenxin , Zhou Junming , Chen Hong
Published: July 2015

Photoluminescence (PL) is a nondestructive and powerful method to investigate carrier recombination and transport characteristics in semiconductor materials. In this study, the temperature dependences of photoluminescence of GaAs-AlxGa1-xAs multi-quantum wells samples with and without p-n junction were measured under both resonant and non-resonant excitation modes. An obvious increase of photoluminescence(PL) intensity as the rising of temperature in low temperature range (T < 50 K), is observed only for GaAs-AlxGa1-xAs quantum wells sample with p-n junction under non-resonant excitation. The origin of the anomalous increase of integrated PL intensity proved to be associated with the enhancement of carrier drifting because of the increase of carrier mobility in the temperature range from 15 K to 100 K. For non-resonant excitation, carriers supplied from the barriers will influence the temperature dependence of integrated PL intensity of quantum wells, which makes the traditional methods to acquire photoluminescence characters from the temperature dependence of integrated PL intensity unavailable. For resonant excitation, carriers are generated only in the wells and the temperature dependence of integrated PL intensity is very suitable to analysis the photoluminescence characters of quantum wells.
FFA-ROS-P53-mediated mitochondrial apoptosis contributes to reduction of osteoblastogenesis and bone mass in type 2 diabetes mellitus
Authors: Li Jun , He Wang , Liao Bo , Yang Jingyue
Published: July 2015

This study evaluated the association between free fatty acid (FFA), ROS generation, mitochondrial dysfunction and bone mineral density (BMD) in type 2 diabetic patients and investigated the molecular mechanism. db/db and high fat (HF)-fed mice were treated by Etomoxir, an inhibitor of CPT1, MitoQ and PFT-α, an inhibitor of P53. Bone metabolic factors were assessed and BMSCs were isolated and induced to osteogenic differentiation. FFA, lipid peroxidation and mtDNA copy number were correlated with BMD in T2DM patients. Etomoxir, MitoQ and PFT-α significantly inhibited the decrease of BMD and bone breaking strength in db/db and HF-fed mice and suppressed the reduction of BMSCs-differentiated osteoblasts. Etomoxir and MitoQ, but not PFT-α, inhibited the increase of mitochondrial ROS generation in db/db and HF-fed mice and osteoblasts. In addition, Etomoxir, MitoQ and PFT-α significantly inhibited mitochondrial dysfunction in osteoblasts. Moreover, mitochondrial apoptosis was activated in osteoblasts derived from db/db and HF-fed mice, which was inhibited by Etomoxir, MitoQ and PFT-α. Furthermore, mitochondrial accumulation of P53 recruited Bax and initiated molecular events of apoptotic events. These results demonstrated that fatty acid oxidation resulted in ROS generation, activating P53/Bax-mediated mitochondrial apoptosis, leading to reduction of osteogenic differentiation and bone loss in T2DM.
Mechanical properties and microstructural change of W–Y2O3 alloy under helium irradiation
Authors: Tan Xiaoyue , Luo Laima , Chen Hongyu , Zhu Xiaoyong , Zan Xiang , Luo Guangnan , Chen Junling , Li Ping , Cheng Jigui , Liu Dongping , Wu Yucheng
Published: July 2015

A wet-chemical method combined with spark plasma sintering was used to prepare a W–Y2O3 alloy. High-temperature tensile tests and nano-indentation microhardness tests were used to characterize the mechanical properties of the alloy. After He-ion irradiation, fuzz and He bubbles were observed on the irradiated surface. The irradiation embrittlement was reflected by the crack indentations formed during the microhardness tests. A phase transformation from α-W to γ-W was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Polycrystallization and amorphization were also observed in the irradiation damage layer. The W materials tended to exhibit lattice distortion, amorphization, polycrystallization and phase transformation under He-ion irradiation. The transformation mechanism predicted by the atomic lattice model was consistent with the available experimental observations. These findings clarify the mechanism of the structural transition of W under ion irradiation and provide a clue for identifying materials with greater irradiation resistance.
Molecular Signatures of Reduced Nerve Toxicity by CeCl3 in Phoxim-exposed Silkworm Brains
Authors: Wang Binbin , Li Fanchi , Ni Min , Zhang Hua , Xu Kaizun , Tian Jianghai , Hu Jingsheng , Shen Weide , Li Bing
Published: July 2015

CeCl3 can reduce the damage caused by OP pesticides, in this study we used the brain of silkworms to investigate the mechanism of CeCl3 effects on pesticide resistance. The results showed that phoxim treatments led to brain damages, swelling and death of neurons, chromatin condensation and mitochondrial damage. Normal nerve conduction was severely affected by phoxim treatments, as revealed by: increases in the contents of neurotransmitters Glu, NO and ACh by 63.65%, 61.14% and 98.54%, respectively; decreases in the contents of 5-HT and DA by 53.19% and 43.71%, respectively; reductions in the activities of Na+/K+-ATPase, Ca2+/Mg2+-ATPase and AChE by 85.27%, 85.63% and 85.63%, respectively; and increase in the activity of TNOS by 22.33%. CeCl3 pretreatment can significantly reduce such damages. Results of DGE and qRT-PCR indicated that CeCl3 treatments significantly upregulated the expression levels of CYP4G23, cyt-b5, GSTs-σ1, ace1, esterase-FE4 and β-esterase 2. Overall, phoxim treatments cause nerve tissue lesions, neuron death and nerve conduction hindrance, but CeCl3 pretreatments can promote the expression of phoxim resistance-related genes in silkworm brains to reduce phoxim-induced damages. Our study provides a potential new method to improve the resistance of silkworms against OP pesticides.
RETRACTED ARTICLE: γ-Aminobutyric acid (GABA) administration improves action selection processes: a randomised controlled trial
Authors: Steenbergen Laura , Sellaro Roberta , Stock Ann-Kathrin , Beste Christian , Colzato Lorenza S.
Published: July 2015

In order to accomplish a task goal, real-life environments require us to develop different action control strategies in order to rapidly react to fast-moving visual and auditory stimuli. When engaging in complex scenarios, it is essential to prioritise and cascade different actions. Recent studies have pointed to an important role of the gamma-aminobutyric acid (GABA)-ergic system in the neuromodulation of action cascading. In this study we assessed the specific causal role of the GABA-ergic system in modulating the efficiency of action cascading by administering 800 mg of synthetic GABA or 800 mg oral of microcrystalline cellulose (placebo). In a double-blind, randomised, between-group design, 30 healthy adults performed a stop-change paradigm. Results showed that the administration of GABA, compared to placebo, increased action selection when an interruption (stop) and a change towards an alternative response were required simultaneously and when such a change had to occur after the completion of the stop process. These findings, involving the systemic administration of synthetic GABA, provide the first evidence for a possible causal role of the GABA-ergic system in modulating performance in action cascading.
TRPA1 mediates the hypothermic action of acetaminophen
Authors: Gentry Clive , Andersson David A. , Bevan Stuart
Published: July 2015

Acetaminophen (APAP) is an effective antipyretic and one of the most commonly used analgesic drugs. Unlike antipyretic non-steroidal anti-inflammatory drugs, APAP elicits hypothermia in addition to its antipyretic effect. Here we have examined the mechanisms responsible for the hypothermic activity of APAP. Subcutaneous, but not intrathecal, administration of APAP elicited a dose dependent decrease in body temperature in wildtype mice. Hypothermia was abolished in mice pre-treated with resiniferatoxin to destroy or defunctionalize peripheral TRPV1-expressing terminals, but resistant to inhibition of cyclo-oxygenases. The hypothermic activity was independent of TRPV1 since APAP evoked hypothermia was identical in wildtype and Trpv1−/− mice and not reduced by administration of a maximally effective dose of a TRPV1 antagonist. In contrast, a TRPA1 antagonist inhibited APAP induced hypothermia and APAP was without effect on body temperature in Trpa1−/− mice. In a model of yeast induced pyrexia, administration of APAP evoked a marked hypothermia in wildtype and Trpv1−/− mice, but only restored normal body temperature in Trpa1−/− and Trpa1−/−/Trpv1−/− mice. We conclude that TRPA1 mediates APAP evoked hypothermia.
Asymmetric [1,5]-Hydride Transfer Reactions
Authors: Liang Xiao-Wei , Zheng Chao , You Shu-Li
Published: July 2015

As an emerging method for the direct asymmetric functionalization of C(sp3)–H bonds, the asymmetric [1,5]-hydride transfer reactions have received considerable attention in recent years. The remarkable features of these reactions include their redox-neutral nature and facile access to versatile polycyclic scaffolds when coupled with the downstream cyclization process. Thanks to the continuous efforts in this field, an array of effective catalytic systems such as chiral organocatalysts, Lewis acids, and binary acid catalysts that are capable of promoting asymmetric [1,5]-hydride transfer reactions has been identified. This chapter will focus on providing a concise description of the state-of-the-art of this exciting area.
Asymmetric Friedel–Crafts Alkylation Reactions
Authors: Kang Qiang , You Shu-Li
Published: July 2015

The asymmetric Friedel–Crafts (AFC) alkylation reaction is one of the most important approaches to the synthesis of optically pure organic compounds. Various catalytic systems, including well-defined organometallic complexes (Zn, Cu, Sc, etc.) and small organic molecules (chiral imidazolidinones, thioureas, prolinols, BINOL-derived phosphoric acids, etc.), have been successfully developed and applied in asymmetric Friedel–Crafts alkylation reactions. Remarkable levels of enantioselectivity have been achieved for electron-rich arenes such as indoles, pyrroles, and naphthols, and electrophiles such as carbonyl compounds, imines, α,β-unsaturated carbonyl compounds, and π-allyl metal species.
N-Heterocyclic Carbene-Catalyzed Asymmetric Functionalization of Aldehyde C–H Bonds
Authors: Li Yi , You Shu-Li
Published: July 2015

Asymmetric C–H bond functionalization is an extremely attractive research area. The unique catalytic ability of N-heterocyclic carbene (NHC) provides a conventional access to various types of synthetically useful compounds by activation of aldehyde C–H bonds. Since the groundbreaking mechanistic explanation on 1958 by Breslow and the unequivocally established isolation and characterization of stable NHC by Arduengo in 1991, the conception of umpolung of NHC catalysis has been widely accepted and this chemistry of asymmetric activation of aldehyde C–H bonds has attracted much attention as an important subfield in organocatalysis thereafter. This chapter will focus on the recent developments on NHC-catalyzed asymmetric functionalization of aldehyde C–H bonds (contributions mainly after 2010). Based on the diverse catalytic modes of NHC with different functionalized aldehyde substrates, the sections of the chapter are arranged in the following order: acyl anions, homoenolate equivalents, enolate equivalents, and α,β-unsaturated acyl azolium intermediates.
Asymmetric Hydroacylation Reactions
Authors: Xu Qing-Long , You Shu-Li
Published: July 2015

The hydroacylation reaction is an attractive subfield of C–H bond functionalization reactions, realizing direct transformation of the acyl C–H bond of aldehydes. The asymmetric hydroacylation reactions, either intra- or intermolecular, have been developed in recent years with various catalytic systems, among which the Rh-based catalysts hold a central position. In this chapter, we present recent developments of the asymmetric hydroacylation of alkenes, allenes, alkynes, and ketones.
Label-free photoelectrochemical cytosensing via resonance energy transfer using gold nanoparticle-enhanced carbon dots
Authors: Liu Shanshan , Cao Huijuan , Wang Zhaoyin , Tu Wenwen , Dai Zhihui
Published: July 2015

A universal and label-free photoelectrochemical biosensing platform for the direct detection of HeLa cells was developed based on carbon-dots–AuNPs–cysteamine conjugates.
Two site genetic incorporation of varying length polyethylene glycol into the backbone of one peptide
Authors: Zang Qingmin , Tada Seiichi , Uzawa Takanori , Kiga Daisuke , Yamamura Masayuki , Ito Yoshihiro
Published: July 2015

Polyethylene glycol (PEG) of different lengths was genetically incorporated into the backbone of a polypeptide using stop-anticodon and frameshift anticodon-containing tRNAs, which were acylated with PEG-containing amino acids.
Functionalized ultrathin palladium nanosheets as patches for HepG2 cancer cells
Authors: Pan Yung-Tin , Smith Cartney E. , Kwok Kam Sang , Chen Jinrong , Kong Hyunjoon , Yang Hong
Published: July 2015

Flexible Pd nanosheets functionalized with carboxylic acid and amine ligands show different cytotoxicity.
Reversible stimulus-responsive Cu(i) iodide pyridine coordination polymer
Authors: Amo-Ochoa P. , Hassanein K. , Gómez-García C. J. , Benmansour S. , Perles J. , Castillo O. , Martínez J. I. , Ocón P. , Zamora F.
Published: July 2015

A coordination polymer based on CuI double chains with substituted pyrimidine is a dynamic and reversible material very sensible to both physical and chemical stimuli.
A luminescent ruthenium(ii) complex for light-triggered drug release and live cell imaging
Authors: Karaoun Nora , Renfrew Anna K.
Published: July 2015

We report a novel ruthenium(ii) complex for selective release of the imidazole-based drug econazole. Release of the econazole ligand induces both a turn-off luminescence response and photoselective toxicity.
Homogeneous liquid–liquid extraction of metal ions with non-fluorinated bis(2-ethylhexyl)phosphate ionic liquids having a lower critical solution temperature in combination with water
Authors: Depuydt Daphne , Liu Liwang , Glorieux Christ , Dehaen Wim , Binnemans Koen
Published: July 2015

Bis(2-ethylhexyl)phosphate ionic liquids show a temperature-dependent phase behaviour of the LCST-type and can extract transition metal ions very efficiently via homogeneous liquid–liquid extraction.
Converting 3D rigid metal–organic frameworks (MOFs) to 2D flexible networks via ligand exchange for enhanced CO2/N2 and CH4/N2 separation
Authors: He Yingdian , Shang Jin , Gu Qinfen , Li Gang , Li Jiaye , Singh Ranjeet , Xiao Penny , Webley Paul A.
Published: July 2015

Ligand exchange converts a 3D rigid MOF into a unique 2D flexible network achieving enhanced gas separation.
Highly selective two-photon imaging of cysteine in cancerous cells and tissues
Authors: Lee Yun Hak , Ren Wen Xiu , Han Jiyou , Sunwoo Kyoung , Lim Ja-Yun , Kim Jong-Hoon , Kim Jong Seung
Published: July 2015

Abnormal concentrations of Cys have been reported to be implicated in various health problems, including cancer, neuropathy, and cardiomyopathy.
Thin polymer-layer decorated, structure adjustable crystals of nanoparticles
Authors: Cao Xue-Zheng , Duan Zhi-Guang , Wang Jun-Shu , Cui Wei , Liu Yong-Song , Wu Chen-Xu
Published: July 2015

Polymer chains take a two dimensional thin layer conformation on substrates, instead of being stretched by dense nanoparticles.
Corrole–ferrocene and corrole–anthraquinone dyads: synthesis, spectroscopy and photochemistry
Authors: Kandhadi Jaipal , Yeduru Venkatesh , Bangal Prakriti R. , Giribabu Lingamallu
Published: July 2015

Two different donor–acceptor systems based on corrole–ferrocene (Cor–Fc) and corrole–anthraquinone (Cor–AQ) have been designed and synthesized. Excited state properties of these dyads indicates intramolecular photoinduced electron transfer (PET) take place in these dyads and the electron-transfer rates (kET) was found to be ∼1011s−1. The charge separation (CS) and charge recombination (CR) are found to be identical.
Molecular dynamics study of interfacial thermal transport between silicene and substrates
Authors: Zhang Jingchao , Hong Yang , Tong Zhen , Xiao Zhihuai , Bao Hua , Yue Yanan
Published: July 2015

For the first time, the interfacial thermal resistance between silicene and multiple substrates,i.e., crystalline silicon and silica, amorphous silicon and silica are calculated using a transient heating molecular dynamics technique.
Surface effect on the electromelting behavior of nanoconfined water
Authors: Bose Arnab , Metya Atanu K. , Singh Jayant K.
Published: July 2015

Lateral diffusivity of water under confinement as a function of electric field.
Synthesis, structure and reactivity of a donor-stabilised silylene with a bulky bidentate benzamidinato ligand
Authors: Tacke Reinhold , Kobelt Claudia , Baus Johannes A. , Bertermann Rüdiger , Burschka Christian
Published: July 2015

A novel donor-stabilised silicon(ii) complex with an SiN3 skeleton was synthesised and its reactivity profile was characterised (reactions with N2O, S8, Se, Te, Me3SiN3, PhSCH2N3 and [Fe(CO)5]).
Bioaccessibility of lipophilic micro-constituents from a lipid emulsion
Authors: Marze Sébastien
Published: July 2015

The physicochemical parameters controlling the transfer of lipophilic micro-constituents from emulsion droplets to mixed micelles (bioaccessibility) are reviewed.
Computational predictions of corroles as a class of Hsp90 inhibitors
Authors: Teo Ruijie D. , Dong Sijia S. , Gross Zeev , Gray Harry B. , Goddard William A.
Published: July 2015

We predict corroles as a promising class of Hsp90 inhibitors by applying docking studies and molecular dynamics simulations.
Planar and distorted indigo as the core motif in novel chromophoric liquid crystals
Authors: Porada Jan H. , Neudörfl Jörg-M. , Blunk Dirk
Published: July 2015

The phase behaviour of calamitic indigoid liquid crystals was investigated and rationalised on the basis of a crystal structure analysis.
In situ synthesis of porous array films on a filament induced micro-gap electrode pair and their use as resistance-type gas sensors with enhanced performances
Authors: Xu Zongke , Duan Guotao , Zhang Hongwen , Wang Yingying , Xu Lei , Cai Weiping
Published: July 2015

In this paper, a new gas sensor of metal-oxide porous array films on a micro-gap electrode pair is designed and implemented by taking ZnO as a model material.
Modeling nanoparticle wrapping or translocation in bilayer membranes
Authors: Curtis Emily M. , Bahrami Amir H. , Weikl Thomas R. , Hall Carol K.
Published: July 2015

The molecular level interaction between nanoparticles and lipid membranes, including wrapping, is simulated using discontinuous molecular dynamics with the LIME force field.
Study of the interactions between endolysin and bacterial peptidoglycan on S. aureus by dynamic force spectroscopy
Authors: Liu Jianli , Zhang Xuejie , Yang Hang , Yuan Jinghe , Wei Hongping , Yu Junping , Fang Xiaohong
Published: July 2015

The cell wall binding domain (CBD) of bacteriophage lysins can bind to host bacteria with comparable binding strength as antibody, demonstrating it is a promising new probe to detect the corresponding bacterial pathogen.
Structural defect induced peak splitting in gold–copper bimetallic nanorods during growth by single particle spectroscopy
Authors: Thota Sravan , Chen Shutang , Zhou Yadong , Zhang Yong , Zou Shengli , Zhao Jing
Published: July 2015

Structural defects induce splitting in the plasmon bands of a Au–Cu alloy nanorod during growth compared to a defect free alloy nanorod.
Origins of observed reactivity and specificity in the addition of B2Cl4and analogues to unsaturated compounds
Authors: Pubill-Ulldemolins Cristina , Fernánez Elena , Bo Carles , Brown John M.
Published: July 2015

Catalysed addition of B2X4reagents to alkenes is well established, but the older uncatalysed addition has been neglected recently. By DFT analysis existing observations have been rationalized and predictions made that encourage further experiments.
The impact of zinc oxide nanoparticles on nitrification and the bacterial community in activated sludge in an SBR
Authors: Wang S. T. , Li S. P. , Wang W. Q. , You H.
Published: July 2015

20 and 50 mg L−1 of ZnO NPs affect transformation of NH4+–N to NO2−–N and NO2−–N to NO3−–N.
A comparative ab initio study to investigate the rich structural variety and electronic properties of GamTen (m = 1, 2 and n = 1–4) with analogous oxides, sulfides and selenides
Authors: Seeburrun N. , Alswaidan I. A. , Fun H.-K. , Archibong E. F. , Ramasami P.
Published: July 2015

A series of gallium telluride, GamTen (m = 1, 2 and n = 1–4), clusters has been examined by using different computational methods.
Design and security analysis for the liquefaction and distillation process of oxygen-bearing coal-bed methane
Authors: Cui Gan , Li Zi-Li , Zhao Ya-Lei
Published: July 2015

A new liquefaction and distillation process for oxygen-bearing CBM has been proposed. Safety evaluation and safety measures are also studied.
Environmentally benign synthesis of high-quality, band gap-tunable, homogeneous Te/Se alloyed nanowires
Authors: Zhou Chongjian , Wang Ke , Dun Chaochao , Wang Qiong , Shi Zhongqi , Liu Guiwu , Qiao Guanjun
Published: July 2015

Ultrathin trigonal Te/Se alloyed nanowires with a tunable composition and band gap were fabricated using ascorbic acid as a nonhazardous reducing agent.
Energy transfer properties of a novel boron dipyrromethene–perylenediimide donor–acceptor dyad
Authors: Ermilov Eugeny A. , Schlak Martin , Steffen Ronald , Liu Xiao-Qiong , Liu Jian-Yong , Röder Beate
Published: July 2015

The boron dipyrromethene–perylenediimide dyad has been prepared and studied for its light-harvesting properties with various steady-state and time-resolved spectroscopic methods.
Synthesis and characterization of surface ion-imprinted polymer based on SiO2-coated graphene oxide for selective adsorption of uranium(vi)
Authors: Meng Hu , Li Zheng , Ma Fuyin , Wang Xiaoning , Zhou Wei , Zhang Lan
Published: July 2015

A novel surface ion-imprinted polymer based on graphene oxide was synthesized for the selective adsorption of U(vi).
Facile preparation of carbon-functionalized ordered magnetic mesoporous silica composites for highly selective enrichment of N-glycans
Authors: Zhang Quanqing , Zhang Qinghe , Xiong Zhichao , Wan Hao , Chen Xiaoting , Zou Hanfa
Published: July 2015

A novel carbon-functionalized ordered magnetic mesoporous silica composite was designed and synthesized.
pH-dependent size and structural transition in P123 micelle induced gold nanoparticles
Authors: Chatterjee P. , Hazra S.
Published: July 2015

The transition of the structure and size of AuNPs at a pH value around 9.5, from slowly grown, well-faceted, large (≫19 nm), less uniform and near connected to fast grown, near symmetrical, small (<19 nm), more uniform and well-separated, is observed.
Stabilization and optical switching of liquid crystal blue phase doped with azobenzene-based bent-shaped hydrogen-bonded assemblies
Authors: Wang Jiao , Shi Yang , Yang Kuan , Wei Jie , Guo Jinbao
Published: July 2015

Stabilization and phototuning of the reflection color of BP I have been demonstrated in a BP-LCs by employing a new kind of bent-shaped H-bonded assemblies with azobenzene group.
Aerosol assisted chemical vapour deposition of a ZrO2–TiO2 composite thin film with enhanced photocatalytic activity
Authors: Alotaibi Abdullah M. , Sathasivam Sanjayan , Parkin Ivan P.
Published: July 2015

ZrO2–TiO2 composite thin film deposited via aerosol assisted chemical vapour deposition showed enhanced photocatalytic activity compared to pure anatase TiO2. The photocatalytic properties were determined using resasurin redox dye.
Nano porous hydroxyapatite as a bi-functional catalyst for bio-fuel production
Authors: Viswanadham Nagabhatla , Debnath Suman , Sreenivasulu Peta , Nandan Devaki , Saxena Sandeep K. , Al-Muhtaseb Ala'a H.
Published: July 2015

Nano porous hydroxyapatite possessing acid–base functionality selectively produces 100% solketal at higher glycerol conversions (∼90%).
Synthesis and photophysical properties of β-triazole bridged porphyrin–coumarin dyads
Authors: Singh Dileep Kumar , Nath Mahendra
Published: July 2015

Novel β-triazole bridged porphyrin–coumarin dyads are synthesized via a Cu(i)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction and evaluated for their photophysical properties.
A nona-vacant Keggin-type tricarbonyl rhenium derivative {[PMo3O16][Re(CO)3]4}5− and its catalytic performance for CO2 cycloaddition reactions
Authors: Huo Zhiyuan , Guo Jipeng , Lu Jingkun , Xu Qiaofei , Ma Pengtao , Zhao Juan , Zhang Dongdi , Niu Jingyang , Wang Jingping
Published: July 2015

A nona-vacant Keggin-type tricarbonyl rhenium derivative {[PMo3O16][Re(CO)3]4}5− was synthesized and its frontier orbitals were computed. Interestingly, it showed good catalytic activity for the CO2 cycloaddition reaction.
Using cluster analysis to characterize meaningful learning in a first-year university chemistry laboratory course
Authors: Galloway Kelli R. , Bretz Stacey Lowery
Published: July 2015

The Meaningful Learning in the Laboratory Instrument (MLLI) was designed to measure students' cognitive and affective learning in the university chemistry laboratory. The MLLI was administered at the beginning and the end of the first semester to first-year university chemistry students to measure their expectations and experiences for learning in their laboratory course. To better understand what students' expectations for learning were fulfilled, and what expectations went unmet, cluster analysis was used to examine students' expectations and experiences as measured by their average scores on the MLLI at both the beginning and the end of the semester. The cluster solution yielded four clusters. Three of the four clusters consisted of parallel responses,i.e., the first cluster had both low expectations and low experiences, the third cluster had both high expectations and high experiences, and the second cluster was in the middle of the first and third. The fourth cluster had expectations similar to those of the high cluster, but surprisingly had experiences similar to those of the middle and low clusters. Descriptions of each cluster of students, including distinguishing characteristics of their learning in the laboratory, and the implications of this research are discussed.
Synthesis, characterization, and water oxidation by a molecular chromophore-catalyst assembly prepared by atomic layer deposition. The “mummy” strategy
Authors: Lapides A. M. , Sherman B. D. , Brennaman M. K. , Dares C. J. , Skinner K. R. , Templeton J. L. , Meyer T. J.
Published: July 2015

A Ru(ii)-polypyridyl chromophore-catalyst assembly for light-assisted water oxidation is constructed using atomic layer deposition with no covalent bonds between molecules required for bilayer formation.
Exploring the chemical space of the lysine-binding pocket of the first kringle domain of hepatocyte growth factor/scatter factor (HGF/SF) yields a new class of inhibitors of HGF/SF-MET binding
Authors: Sigurdardottir A. G. , Winter A. , Sobkowicz A. , Fragai M. , Chirgadze D. , Ascher D. B. , Blundell T. L. , Gherardi E.
Published: July 2015

Targeting thelysine-binding pocketof the first kringle domain of HGF/SF using a fragment-based approach identified new chemical entities that can inhibit MET signalling.
Enhanced active motion of Janus colloids at the water surface
Authors: Wang Xiaolu , In Martin , Blanc Christophe , Nobili Maurizio , Stocco Antonio
Published: July 2015

Self-propelled Janus colloids show enhanced active motion when trapped at the water surface. Trajectories are more directional and velocities are higher than those in the bulk. The confinement effect given by the air–water interface strongly reduces the rotational motion of the colloid while not hindering self-propulsion.
Spatial correlations of elementary relaxation events in glass-forming liquids
Authors: Pastore Raffaele , Coniglio Antonio , Ciamarra Massimo Pica
Published: July 2015

We identify the smallest irreversible events in glass formers and investigate their correlations.
Internal stress drives slow glassy dynamics and quake-like behaviour in ionotropic pectin gels
Authors: Mansel Bradley W. , Williams Martin A. K.
Published: July 2015

We explored slow dynamical processes in ionotropic pectin gels as the junction length between bound polymers was modified.
Strongly coupled 1D sandwich-like C@Fe3O4@C coaxial nanotubes with ultrastable and high capacity for lithium-ion batteries
Authors: Qu Qunting , Chen Junmei , Li Xingxing , Gao Tian , Shao Jie , Zheng Honghe
Published: July 2015

A scalable and bottom-up synthesis method is successfully developed for fabricating 1D sandwich-like C@Fe3O4@C coaxial nanotubes, which exhibit excellent lithium storage properties.
Heterostructures of skutterudites and germanium antimony tellurides – structure analysis and thermoelectric properties of bulk samples
Authors: Fahrnbauer Felix , Maier Stefan , Grundei Martin , Giesbrecht Nadja , Nentwig Markus , Rosenthal Tobias , Wagner Gerald , Snyder G. Jeffrey , Oeckler Oliver
Published: July 2015

The precipitation of skutterudite-type crystallites in germanium antimony tellurides yields intriguing materials with respect to their thermoelectric performance, especially due to a very low phononic part of the lattice thermal conductivity.
The effect of device geometry and crystal orientation on the stress-dependent offset voltage of 3C–SiC(100) four terminal devices
Authors: Qamar Afzaal , Phan Hoang-Phuong , Han Jisheng , Tanner Philip , Dinh Toan , Wang Li , Dimitrijev Sima , Dao Dzung Viet
Published: July 2015

This communication reports for the first time, the impact of device geometry on the stress-dependent offset voltage of single crystal p-type 3C–SiC four terminal devices.
Negative induction effect of graphite N on graphene quantum dots: tunable band gap photoluminescence
Authors: Zhu Chong , Yang Siwei , Wang Gang , Mo Runwei , He Peng , Sun Jing , Di Zengfeng , Yuan Ningyi , Ding Jianning , Ding Guqiao , Xie Xiaoming
Published: July 2015

We synthesized nitrogen-doped graphene quantum dots (N-GQDs) under a high temperature range of 800–1200 °C and high pressure of 4.0 GPa through a solid-to-solid process.
Isolated superior rectus abscess following traumatic blunt injury to the eye
Authors: Singhal Namit , Sahu Rabi Narayan , Kalra Samir Kumar , Sharma Kumudini , Mahapatra Ashok Kumar , Kumar Raj
Published: July 2015

Orbital abscess following trivial blunt trauma to the eye are uncommon. Few cases are known and reported in the literature. The clinical presentation can be myriad varying from localized presentation to children with marked systemic toxicity. Visual loss is the most dreaded complication and a rapid deterioration in vision may occur if the treatment is delayed. Radiological investigations usually offer a prompt diagnosis but considerable degree of confusion may occur, especially in those cases that lack systemic manifestations of infective pathology. Aggressive medical and surgical treatment is mandatory for a favorable outcome in these cases. We report the case of a child who presented to us with orbital abscess of the left eye following a trivial blunt trauma. No other infective focus was identified. Subsequent imaging revealed abscess of the superior rectus muscle. The child improved following intravenous antibiotics and ultrasonography guided aspiration of the abscess. The clinical and radiological presentation of such cases, management and outcome and a brief review of literature are discussed.
Orientational ordering and phase behaviour of binary mixtures of hard spheres and hard spherocylinders
Authors: Wu Liang , Malijevský Alexandr , Jackson George , Müller Erich A. , Avendaño Carlos
Published: July 2015

We study the structure and fluid-phase behaviour of binary mixtures of hard spheres (HSs) and hard spherocylinders (HSCs) in isotropic and nematic states using the NPnAT ensemble Monte Carlo (MC) approach in which the normal component of the pressure tensor is fixed in a system confined between two hard walls. The method allows one to estimate the location of the isotropic-nematic phase transition and to observe the asymmetry in the composition between the coexisting phases, with the expected enhancement of the HSC concentration in the nematic phase. This is in stark contrast with the previously reported MC simulations where a conventional isotropic NPT ensemble was used. We further compare the simulation results with the theoretical predictions of two analytic theories that extend the original Parsons-Lee theory using the one-fluid and the many-fluid approximations [Malijevský et al., J. Chem. Phys. 129, 144504 (2008)]. In the one-fluid version of the theory, the properties of the mixture are related to an effective one-component HS system, while in the many-fluid theory, the components of the mixtures are represented as separate effective HS particles. The comparison reveals that both the one- and the many-fluid approaches provide a reasonably accurate quantitative description of the mixture including the predictions of the isotropic-nematic phase boundary and degree of orientational order of the HSC-HS mixture.
Thermal conductivity of donor-doped GaN measured with 3ω and stationary methods
Authors: Churiukova O. , Jeżowski A. , Stachowiak P. , Mucha J. , Litwicki Z. , Perlin P. , Suski T.
Published: July 2015

The thermal conductivity of three single crystal samples of n-type gallium nitride with electron densities of 4.0 × 1016, 2.6 × 1018, and 1.1 × 1020 cm−3 has been determined in the temperature range 4–320 K. The measurements were carried out within the ab plane using the stationary method. The thermal conductivity depends strongly on the donor concentration. The analysis within the Callaway approach and the Debye model shows a significant influence of phonon-electron scattering on the thermal conductivity of the samples. In addition, some preliminary results obtained along the c axes of GaN layered samples are presented. The latter measurements have been carried out using the 3ω method.
The standardization and certification procedures of cryogenic equipment in Kazakhstan
Authors: Shinbayeva A. , Drobyshev A. , Drobyshev N.
Published: July 2015

The complex of procedures on stepwise carrying out actions of standardization and certification of liquid nitrogen, argon and oxygen gasificator G-200 is considered. In the process of organization of standardization and certification procedures the set of regulatory documents was developed that allow starting small-scale production of gasificators in Kazakhstan. Thus the emphasis on the potential incorporation of the requirements of such documents is placed from the Eurasian Economic Union.
Superconducting properties of ultra-pure niobium welded joints
Authors: Demyanov S. E. , Kaniukov E. Yu. , Pobol I. L. , Yurevich S. V. , Baturitsky M. A. , Shirkov G. D. , Budagov Yu. A. , Demin D. L. , Azaryan N. S.
Published: July 2015

An optimal electron-beam welding operating regime for ultra-pure sheet niobium has been developed for use in a superconducting resonator for the International Linear Collider (ILC). The formation of weld joints is studied and their microstructure and microhardness are investigated taking the required geometry of the weld seams into account. Low-temperature electrical measurements in magnetic fields up to 2 T are used to determine the critical parameters of the superconducting transition in the weld area. From the standpoint of the superconducting properties of the resonator, the slight degradation in the characteristics of sheet niobium observed in the thermally affected area (about 10% on average) is not of fundamental importance.
Thin-film coating of surfactant-laden liquids on rotating cylinders
Authors: Li Weihua , Kumar Satish
Published: July 2015

Motivated by the need to improve fundamental understanding of the coating of discrete objects, the influence of surfactants on the flow of thin liquid films around rotating cylinders is considered in this work. The lubrication approximation is applied to derive three coupled nonlinear evolution equations describing the variation of the film thickness, surfactant surface concentration, and surfactant bulk concentration as a function of time and the angular coordinate. In the absence of gravitational effects, linear stability analysis reveals that Marangoni stresses suppress the growth rate of instabilities driven by centrifugal forces and hinder the leveling of perturbations to the film thickness. When gravitational effects are present, Marangoni stresses lower the critical rotation rate needed to cause motion of a liquid lobe around the cylinder. These stresses also lead to faster damping of oscillations in the film thickness at relatively short times, but if strong enough, it can increase the oscillation amplitude at longer times. In all cases examined, surfactant solubility has the effect of weakening the influence of Marangoni stresses.
Electric polarization of He II by quantized vortices
Authors: Adamenko I. N. , Nemchenko E. K.
Published: July 2015

It is shown that when the superfluid component of 4He is in motion relative to the quantized vortices of superfluid helium (He II), an electric field appears, caused by the electric properties of the quantized vortices, which are generated by the polarization of the liquid during its motion around the vortex core. In a state of thermodynamic equilibrium and in an isotropic and homogenous liquid such as superfluid 4He, the electric field generated by the quantized vortices is equal to zero. However, anisotropy occurs during the relative motion of the superfluid and normal components, which include quantized vortices, due to the difference in the velocities between the normal and superfluid components. This anisotropy and the electric properties of the quantized vortices lead to the creation of an electric field in He II. The calculated results given in the article are compared to the experimental data.
Galvanomagnetic phenomena in organic conductors under topological phase transition
Authors: Galbova O. , Peschansky V. G. , Stepanenko D. I.
Published: July 2015

The magnetoresistance of layered organic conductors with a multisheet Fermi surface (FS) is studied theoretically under conditions of the Lifshitz topological transition, where the FS topology may change in response to external effects acting on the conductor, such as pressure or doping with impurity atoms. Using as an example the Fermi surface consisting of a cylinder and two planes, which are slightly corrugated along the projection of the momentum pz=pn along the normal to the layers n, we analyze the magnetic-field dependence of the resistance and the Hall field in a strong external magnetic field H, where the cyclotron frequency ωc of the conduction electrons is much higher than their collision frequency 1/τ. In the immediate vicinity of the topological transition, where the distance between the different sheets of the FS becomes small, an electron can move from one sheet of the FS to another with the probability w due to the magnetic breakdown. In this case, a quadratic increase of the electric resistance across the layers with magnetic field, which occurs in the absence of the magnetic breakdown, is replaced by a linear dependence on H for w≥γ=1/ωcτ, and then reaches saturation for (1−w)≤γ. The Hall field depends substantially on the probability of a magnetic breakdown, but in the case of ωcτ≫1, its asymptote is independent of τ for all values of w. At w = 1, the quasi-planar sheets of the Fermi surface touch the corrugated cylinders, and under further perturbation acting on the conductor, there occurs a break of a flat sheet along the line of contact. As a result, separate sections of the flat FS sheet together with the cut halves of the corrugated cylinder form a new corrugated cylinder with the sign of charge carriers reversed. This is not the only scenario of the Lifshitz topological transition. Studies of the Hall effect will allow us to obtain further important information on the nature of changes in the topological structure of the electron energy spectrum under the phase transition.
Regularity of weak solutions to nonlinear Maxwell systems
Authors: Pan Xing-Bin
Published: July 2015

We examine regularity of weak solutions of several nonlinear Maxwell systems by using the reduction method. This method reduces the original system into two div-curl systems and an oblique derivative problem of a quasilinear elliptic equation and makes it possible to improve the regularity of the solutions by iteration. The reduction method is also used to show existence of classical solutions for a time-independent thermoelectrical model.
Poole-Frenkel effect and variable-range hopping conduction in metal/YBCO resistive switching devices
Authors: Schulman A. , Lanosa L. F. , Acha C.
Published: July 2015

Current-voltage (IV) characteristics and the temperature dependence of the contact resistance [R(T)] of Au/YBa2Cu3O7−δ (optimally doped YBCO) interfaces have been studied at different resistance states. These states were produced by resistive switching after accumulating cyclic electrical pulses of increasing number and voltage amplitude. The IV characteristics and the R(T) dependence of the different states are consistent with a Poole-Frenkel (P-F) emission mechanism with trapping-energy levels Et in the 0.06–0.11 eV range. Et remains constant up to a number-of-pulses-dependent critical voltage and increases linearly with a further increase in the voltage amplitude of the pulses. The observation of a P-F mechanism reveals the existence of an oxygen-depleted layer of YBCO near the interface. A simple electrical transport scenario is discussed, where the degree of disorder, the trap energy level, and the temperature range determine an electrical conduction dominated by non-linear effects, either in a P-F emission or in a variable-range hopping regime.
Dynamics of water around the complex structures formed between the KH domains of far upstream element binding protein and single-stranded DNA molecules
Authors: Chakraborty Kaushik , Bandyopadhyay Sanjoy
Published: July 2015

Single-stranded DNA (ss-DNA) binding proteins specifically bind to the single-stranded regions of the DNA and protect it from premature annealing, thereby stabilizing the DNA structure. We have carried out atomistic molecular dynamics simulations of the aqueous solutions of two DNA binding K homology (KH) domains (KH3 and KH4) of the far upstream element binding protein complexed with two short ss-DNA segments. Attempts have been made to explore the influence of the formation of such complex structures on the microscopic dynamics and hydrogen bond properties of the interfacial water molecules. It is found that the water molecules involved in bridging the ss-DNA segments and the protein domains form a highly constrained thin layer with extremely retarded mobility. These water molecules play important roles in freezing the conformational oscillations of the ss-DNA oligomers and thereby forming rigid complex structures. Further, it is demonstrated that the effect of complexation on the slow long-time relaxations of hydrogen bonds at the interface is correlated with hindered motions of the surrounding water molecules. Importantly, it is observed that the highly restricted motions of the water molecules bridging the protein and the DNA components in the complexed forms originate from more frequent hydrogen bond reformations.
Enhanced H-filter based on Fåhræus-Lindqvist effect for efficient and robust dialysis without membrane
Authors: Zheng Wei-Chao , Xie Rui , He Li-Qun , Xi Yue-Heng , Liu Ying-Mei , Meng Zhi-Jun , Wang Wei , Ju Xiao-Jie , Chen Gang , Chu Liang-Yin
Published: July 2015

A novel microfluidic device for highly efficient and robust dialysis without membrane is highly desired for the development of portable or wearable microdialyzer. Here we report an enhanced H-filter with pillar array based on Fåhræus-Lindqvist effect (F-L effect) for highly efficient and robust membraneless dialysis of simplified blood for the first time. The H-filter employs two fluids laminarly flowing in the microchannel for continuously membraneless dialysis. With pillar array in the microchannel, the two laminar flows, with one containing blood cells and small molecules and another containing dialyzate solution, can form a cell-free layer at the interface as selective zones for separation. This provides enhanced mixing yet extremely low shear for extraction of small molecules from the blood-cell-containing flow into the dialyzate flow, resulting in robust separation with reduced cell loss and improved efficiency. We demonstrate this by first using Chlorella pyrenoidosa as model cells to quantitatively study the separation performances, and then using simplified human blood for dialysis. The advanced H-filter, with highly efficient and robust performance for membraneless dialysis, shows great potential as promising candidate for rapid blood analysis/separation, and as fundamental structure for portable dialyzer.
Lattice Boltzmann simulations of a viscoelastic shear-thinning fluid
Authors: Papenkort S. , Voigtmann Th.
Published: July 2015

We present a hybrid lattice Boltzmann algorithm for the simulation of flow glass-forming fluids, characterized by slow structural relaxation, at the level of the Navier-Stokes equation. The fluid is described in terms of a nonlinear integral constitutive equation, relating the stress tensor locally to the history of flow. As an application, we present results for an integral nonlinear Maxwell model that combines the effects of (linear) viscoelasticity and (nonlinear) shear thinning. We discuss the transient dynamics of velocities, shear stresses, and normal stress differences in planar pressure-driven channel flow, after switching on (startup) and off (cessation) of the driving pressure. This transient dynamics depends nontrivially on the channel width due to an interplay between hydrodynamic momentum diffusion and slow structural relaxation.
Enhancement of beam pulse controllability for a single-pulse formation system of a cyclotron
Authors: Kurashima Satoshi , Miyawaki Nobumasa , Kashiwagi Hirotsugu , Okumura Susumu , Taguchi Mitsumasa , Fukuda Mitsuhiro
Published: July 2015

The single-pulse formation technique using a beam chopping system consisting of two types of high-voltage beam kickers was improved to enhance the quality and intensity of the single-pulse beam with a pulse interval over 1 μs at the Japan Atomic Energy Agency cyclotron facility. A contamination rate of neighboring beam bunches in the single-pulse beam was reduced to less than 0.1%. Long-term purification of the single pulse beam was guaranteed by the well-controlled magnetic field stabilization system for the cyclotron magnet. Reduction of the multi-turn extraction number for suppressing the neighboring beam bunch contamination was achieved by restriction of a beam phase width and precise optimization of a particle acceleration phase. In addition, the single-pulse beam intensity was increased by a factor of two or more by a combination of two types of beam bunchers using sinusoidal and saw-tooth voltage waveforms. Provision of the high quality intense single-pulse beam contributed to improve the accuracy of experiments for investigation of scintillation light time-profile and for neutron energy measurement by a time-of-flight method.