bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative assessment of maternal biomarkers related to one-carbon metabolism and neural tube defects
Authors: Tang Ke-Fu , Li Yao-Long , Wang Hong-Yan
Published: March 2015

Periconceptional supplementation with folic acid reduces the occurrence of neural tube defects (NTDs). The association between maternal abnormalities in homocysteine metabolism (e.g., hyperhomocysteinaemia, folate deficiency and low vitamin B12) and the risk of NTDs-affected pregnancies has been widely evaluated in recent years, although the results are conflicting. To investigate this inconsistency, we performed a meta-analysis of 32 studies, involving 1,890 NTD-affected mothers and 3,995 control mothers, to develop an understanding of the relationship between maternal biomarkers related to one-carbon metabolism and NTD. A random-effects model was used to calculate the ratio of means (RoM) between the cases and controls, along with the 95% confidence intervals (CIs). A significant increase in homocysteine levels was observed in NTD-affected mothers compared with controls (RoM: 1.16, 95% CI: 1.09–1.23, P = 1.8 × 10−6). The pooled analysis also revealed that NTD-affected mothers had significantly lower levels of folate (RoM: 0.93, 95% CI: 0.88–0.97, P = 0.002), vitamin B12 (RoM: 0.91, 95% CI: 0.87–0.95, P = 3.6 × 10−5) and red blood cell folate (RoM: 0.92, 95% CI: 0.86–0.98, P = 0.01). Therefore, altered plasma levels of biomarkers related to one-carbon metabolism are associated with NTD-affected pregnancies.
Important biological information uncovered in previously unaligned reads from chromatin immunoprecipitation experiments (ChIP-Seq)
Authors: Ouma Wilberforce Zachary , Mejia-Guerra Maria Katherine , Yilmaz Alper , Pareja-Tobes Pablo , Li Wei , Doseff Andrea I. , Grotewold Erich
Published: March 2015

Establishing the architecture of gene regulatory networks (GRNs) relies on chromatin immunoprecipitation followed by massively parallel sequencing (ChIP-Seq) methods that provide genome-wide transcription factor binding sites (TFBSs). ChIP-Seq furnishes millions of short reads that, after alignment, describe the genome-wide binding sites of a particular TF. However, in all organisms investigated an average of 40% of reads fail to align to the corresponding genome, with some datasets having as much as 80% of reads failing to align. We describe here the provenance of previously unaligned reads in ChIP-Seq experiments from animals and plants. We show that a substantial portion corresponds to sequences of bacterial and metazoan origin, irrespective of the ChIP-Seq chromatin source. Unforeseen was the finding that 30%–40% of unaligned reads were actually alignable. To validate these observations, we investigated the characteristics of the previously unaligned reads corresponding to TAL1, a human TF involved in lineage specification of hemopoietic cells. We show that, while unmapped ChIP-Seq read datasets contain foreign DNA sequences, additional TFBSs can be identified from the previously unaligned ChIP-Seq reads. Our results indicate that the re-evaluation of previously unaligned reads from ChIP-Seq experiments will significantly contribute to TF target identification and determination of emerging properties of GRNs.
Identification of hybrid node and link communities in complex networks
Authors: He Dongxiao , Jin Di , Chen Zheng , Zhang Weixiong
Published: March 2015

Identifying communities in complex networks is an effective means for analyzing complex systems, with applications in diverse areas such as social science, engineering, biology and medicine. Finding communities of nodes and finding communities of links are two popular schemes for network analysis. These schemes, however, have inherent drawbacks and are inadequate to capture complex organizational structures in real networks. We introduce a new scheme and an effective approach for identifying complex mixture structures of node and link communities, called hybrid node-link communities. A central piece of our approach is a probabilistic model that accommodates node, link and hybrid node-link communities. Our extensive experiments on various real-world networks, including a large protein-protein interaction network and a large network of semantically associated words, illustrated that the scheme for hybrid communities is superior in revealing network characteristics. Moreover, the new approach outperformed the existing methods for finding node or link communities separately.
The lncRNA NRON modulates HIV-1 replication in a NFAT-dependent manner and is differentially regulated by early and late viral proteins
Authors: Imam Hasan , Shahr Bano Aalia , Patel Paresh , Holla Prasida , Jameel Shahid
Published: March 2015

A majority of the human genome is transcribed into noncoding RNAs, of which the functions of long noncoding RNAs (lncRNAs) are poorly understood. Many host proteins and RNAs have been characterized for their roles in HIV/AIDS pathogenesis, but there is only one lncRNA, NEAT1, which is shown to affect the HIV-1 life cycle. We profiled 90 disease-related lncRNAs and found NRON (noncoding repressor of Nuclear Factor of Activated T cells [NFAT]) to be one of several lncRNAs whose expression was significantly altered following HIV-1 infection. The regulation of NRON expression during the HIV-1 life cycle was complex; its levels were reduced by the early viral accessory protein Nef and increased by the late protein Vpu. Consequently, Nef and Vpu also modulated activity of the transcription factor NFAT. The knockdown of NRON enhanced HIV-1 replication through increased activity of NFAT and the viral LTR. Using siRNA-mediated NFAT knockdown, we show the effects of NRON on HIV-1 replication to be mediated by NFAT and the viral Nef and Vpu proteins to modulate NFAT activity through their effects on NRON. These findings add the lncRNA, NRON to the vast repertoire of host factors utilized by HIV for infection and persistence.
The role of seedling recruitment from juvenile populations of Carex brevicuspis (Cyperaceae) at the Dongting Lake wetlands, China
Authors: Deng Zheng-miao , Chen Xin-sheng , Xie Yong-hong , Xie Ya-jun , Hou Zhi-yong , Li Feng
Published: March 2015

Seedlings and vegetative ramets may contribute differentially to the recruitment of clonal populations in different growth phases, but this has rarely been investigated. In this study, we quantified the number and survivorship of seedlings and vegetative ramets monthly in juvenile and mature populations of Carex brevicuspis. During the first growing season after flooding (from October to January), 9 seedlings m−2 (13% of all established shoots) were found in juvenile populations, while no seedlings were found in mature populations. During the second growing season before flooding (from February to May), no new seedling recruits were found either in juvenile or in mature populations. All shoots of seedlings were withered during the dormant season (January and February), but 62.5% seedlings could produce vegetative ramets in the following growing season. During the dormant season, all the early emerging ramets (sprouted in October) withered, but the later emerging ones (sprouted in November and December) survived in both mature and juvenile populations. These results indicated that seedling recruitment was only apparent in juvenile populations of C. brevicuspis. The genetic diversity in mature C.brevicuspis populations may be established in juvenile populations by seedling recruitment and sustained in mature populations by vegetative reproduction.
Optical Nonreciprocity in Asymmetric Optomechanical Couplers
Authors: Wang Zheqi , Shi Lei , Liu Yi , Xu Xinbiao , Zhang Xinliang
Published: March 2015

We propose an all-optical integrated nonreciprocal device on the optomechanical platform with a large nonreciprocal bandwidth and low operating power. The device is based on an asymmetric silicon coupler consisting of two branches. One of them is a conventional strip waveguide fixed on the substrate and the other is a freestanding nanostring suspended above a groove in the substrate. When light is launched into the coupler, the optical gradient force between the freestanding nanostring and the underlying substrate leads to the deflection of the nanostring and finally results in destruction of the initial phase-matching condition between the two branches. The suspended branch would achieve distinct deflections when light is incident from different ports. The simulation results show a nonreciprocal bandwidth of 13.1 nm with operating power of 390 μW. With the advantages of simple structure, low power consumption and large operating bandwidth, our work provides a promising solution for on-chip passive nonreciprocal device.
Association of a nicotinic receptor gene polymorphism with spontaneous eyeblink rates
Authors: Nakano Tamami , Kuriyama Chiho , Himichi Toshiyuki , Nomura Michio
Published: March 2015

Spontaneous eyeblink rates greatly vary among individuals from several blinks to a few dozen blinks per minute. Because dopamine agonists immediately increase the blink rate, individual differences in blink rate are used as a behavioral index of central dopamine functioning. However, an association of the blink rate with polymorphisms in dopamine-related genes has yet not been found. In this study, we demonstrated that a genetic variation of the nicotinic acetylcholine receptor CHRNA4 (rs1044396) increased the blink rate while watching a video. A receiver operating characteristic analysis revealed that the blink rate predicts a genetic variation in the nicotinic receptor gene with a significant discrimination level (0.66, p < 0.004). The present study suggests that differences in sensitivity to acetylcholine because of the genetic variation of the nicotinic receptor are associated with individual differences in spontaneous eye blink rate.
The scent of mixtures: rules of odour processing in ants
Authors: Perez Margot , Giurfa Martin , d'Ettorre Patrizia
Published: March 2015

Natural odours are complex blends of numerous components. Understanding how animals perceive odour mixtures is central to multiple disciplines. Here we focused on carpenter ants, which rely on odours in various behavioural contexts. We studied overshadowing, a phenomenon that occurs when animals having learnt a binary mixture respond less to one component than to the other and less than when this component was learnt alone. Ants were trained individually with alcohols and aldehydes varying in carbon-chain length, either as single odours or binary mixtures. They were then tested with the mixture and the components. Overshadowing resulted from the interaction between chain length and functional group: alcohols overshadowed aldehydes and longer chain lengths overshadowed shorter ones; yet, combinations of these factors could cancel each other and suppress overshadowing. Our results show how ants treat binary olfactory mixtures and set the basis for predictive analyses of odour perception in insects.
Selective spatial attention modulates bottom-up informational masking of speech
Authors: Carlile Simon , Corkhill Caitlin
Published: March 2015

To hear out a conversation against other talkers listeners overcome energetic and informational masking. Largely attributed to top-down processes, information masking has also been demonstrated using unintelligible speech and amplitude-modulated maskers suggesting bottom-up processes. We examined the role of speech-like amplitude modulations in information masking using a spatial masking release paradigm. Separating a target talker from two masker talkers produced a 20 dB improvement in speech reception threshold; 40% of which was attributed to a release from informational masking. When across frequency temporal modulations in the masker talkers are decorrelated the speech is unintelligible, although the within frequency modulation characteristics remains identical. Used as a masker as above, the information masking accounted for 37% of the spatial unmasking seen with this masker. This unintelligible and highly differentiable masker is unlikely to involve top-down processes. These data provides strong evidence of bottom-up masking involving speech-like, within-frequency modulations and that this, presumably low level process, can be modulated by selective spatial attention.
High-throughput preparation methods of crude extract for robust cell-free protein synthesis
Authors: Kwon Yong-Chan , Jewett Michael C.
Published: March 2015

Crude extract based cell-free protein synthesis (CFPS) has emerged as a powerful technology platform for high-throughput protein production and genetic part characterization. Unfortunately, robust preparation of highly active extracts generally requires specialized and costly equipment and can be labor and time intensive. Moreover, cell lysis procedures can be hard to standardize, leading to different extract performance across laboratories. These challenges limit new entrants to the field and new applications, such as comprehensive genome engineering programs to improve extract performance. To address these challenges, we developed a generalizable and easily accessible high-throughput crude extract preparation method for CFPS based on sonication. To validate our approach, we investigated two Escherichia coli strains: BL21 Star™ (DE3) and a K12 MG1655 variant, achieving similar productivity (defined as CFPS yield in g/L) by varying only a few parameters. In addition, we observed identical productivity of cell extracts generated from culture volumes spanning three orders of magnitude (10 mL culture tubes to 10 L fermentation). We anticipate that our rapid and robust extract preparation method will speed-up screening of genomically engineered strains for CFPS applications, make possible highly active extracts from non-model organisms and promote a more general use of CFPS in synthetic biology and biotechnology.
Using visual lateralization to model learning and memory in zebrafish larvae
Authors: Andersson Madelene Åberg , Ek Fredrik , Olsson Roger
Published: March 2015

Impaired learning and memory are common symptoms of neurodegenerative and neuropsychiatric diseases. Present, there are several behavioural test employed to assess cognitive functions in animal models, including the frequently used novel object recognition (NOR) test. However, although atypical functional brain lateralization has been associated with neuropsychiatric conditions, spanning from schizophrenia to autism, few animal models are available to study this phenomenon in learning and memory deficits. Here we present a visual lateralization NOR model (VLNOR) in zebrafish larvae as an assay that combines brain lateralization and NOR. In zebrafish larvae, learning and memory are generally assessed by habituation, sensitization, or conditioning paradigms, which are all representatives of nondeclarative memory. The VLNOR is the first model for zebrafish larvae that studies a memory similar to the declarative memory described for mammals. We demonstrate that VLNOR can be used to study memory formation, storage and recall of novel objects, both short and long term, in 10-day-old zebrafish. Furthermore we show that the VLNOR model can be used to study chemical modulation of memory formation and maintenance using dizocilpine (MK-801), a frequently used non-competitive antagonist of the NMDA receptor, used to test putative antipsychotics in animal models.
Extraordinary sensitivity enhancement by metasurfaces in terahertz detection of antibiotics
Authors: Xie Lijuan , Gao Weilu , Shu Jie , Ying Yibin , Kono Junichiro
Published: March 2015

We have detected trace amounts of molecules of antibiotics (kanamycin sulfate) dispersed on metasurfaces with terahertz (THz) spectroscopy. Utilizing the extraordinary optical transmission resonance of an array of square-shaped slits on a silicon substrate at ~0.3 THz, we were able to monitor varying concentrations of kanamycin sulfate as low as ~100 picogram/L. In contrast, the lowest detectable concentration of kanamycin sulfate on silicon without any metallic structure was ~1 gram/L. This dramatic ~1010 times enhancement of sensitivity is due to the near-field enhancement of THz electric fields by the metamaterial structure. This result thus demonstrates the power and usefulness of metamaterial-assisted THz spectroscopy in trace molecular detection for biological and chemical sensing as well as for food product quality and safety inspection and control.
High precision and selectivity for quantitation of enrofloxacin and ciprofloxacin in five chicken tissues using solid phase extraction and ESI LC-MS/MS for application in monitoring residues
Authors: Gobbo Ferrari Sarita P. , Bonassa Karina P. D. , Coelho Mirela B. , Ferreira Christina R. , Falcão da Costa Heni , Jara José Luis P. , Miguel Maria Carolina V. , Reyes Felix Guillermo R. , Eberlin Marcos N. , Nogueira Guilherme P. , Simas Rosineide C.
Published: March 2015

High-throughput screening (HTS) of Fluoroquinolones (FQs).
Folate-containing reduction-sensitive lipid–polymer hybrid nanoparticles for targeted delivery of doxorubicin
Authors: Wu Bo , Yu Ping , Cui Can , Wu Ming , Zhang Yang , Liu Lei , Wang Cai-Xia , Zhuo Ren-Xi , Huang Shi-Wen
Published: March 2015

Lipid–polymer hybrid nanoparticles (FLPNPs) containing a folate targeted ligand and a reduction-sensitive outer layer were developed to enhance drug delivery efficacy in vitro and in vivo.
Theoretical investigation of quadrupole contributions to surface sum-frequency vibrational spectroscopy
Authors: Zheng Ren-hui , Wei Wen-mei , Shi Qiang
Published: March 2015

We present a new method of calculating quadrupole contributions to surface sum-frequency vibrational spectroscopy.
A facile in situ approach to fabricate N,S-TiO2/g-C3N4 nanocomposite with excellent activity for visible light induced water splitting for hydrogen evolution
Authors: Pany Soumyashree , Parida K. M.
Published: March 2015

The efficient charge separation, small crystallite size and enhanced specific surface area in N,S-TiO2/g-C3N4 nanocomposites make the system pivotal and unique for hydrogen evolution.
The influence of carbon sources on the expression of the recA gene and genotoxicity detection by an Acinetobacter bioreporter
Authors: Jiang Bo , Song Yizhi , Zhang Dayi , Huang Wei E. , Zhang Xu , Li Guanghe
Published: March 2015

Bacterial whole-cell bioreporters are practical and reliable analytical tools to assess the toxicity and bioavailability of environmental contaminants, yet evidence has shown that their performance could be affected by different carbon sources.
Reversible redox modifications in the microglial proteome challenged by beta amyloid
Authors: Correani Virginia , Francesco Laura Di , Cera Isabella , Mignogna Giuseppina , Giorgi Alessandra , Mazzanti Michele , Fumagalli Lorenzo , Fabrizi Cinzia , Maras Bruno , Schininà M. Eugenia
Published: March 2015

Reversible redox modifications of the microglial proteome contribute to switching of these neuronal sentinel cells toward a neuroinflammatory phenotype.
Lessons from the Synthetic Chemist Nature
Authors: Jürjens Gerrit , Kirschning Andreas , Candito David A.
Published: March 2015

Nature's strategy of performing ideal multistep (bio)synthesis are based on multicatalysis, domino reactions, iteration and compartmentation. These are discussed and compared with chemical synthesis in this conceptual review.
The marine actinomycete genus Salinispora: a model organism for secondary metabolite discovery
Authors: Jensen Paul R. , Moore Bradley S. , Fenical William
Published: March 2015

This review covers the discovery of the marine actinomycete genusSalinisporaand its development as a model for natural products research.
New surface radiolabeling schemes of super paramagnetic iron oxide nanoparticles (SPIONs) for biodistribution studies
Authors: Nallathamby Prakash D. , Mortensen Ninell P. , Palko Heather A. , Malfatti Mike , Smith Catherine , Sonnett James , Doktycz Mitchel J. , Gu Baohua , Roeder Ryan K. , Wang Wei , Retterer Scott T.
Published: March 2015

We present different surface radiolabeling schemes broadly applicable to a large class of nanoparticles, with wide implications forin vivobiodistribution studies.
Preparation of AgInS2 quantum dot/In2S3 co-sensitized photoelectrodes by a facile aqueous-phase synthesis route and their photovoltaic performance
Authors: Wang Yuanqiang , Zhang Qinghong , Li Yaogang , Wang Hongzhi
Published: March 2015

A facile aqueous-phase synthesis route for AgInS2-based quantum dot sensitized photoelectrodes with good photovoltaic performance has been reported.
An aptamer-targeting photoresponsive drug delivery system using “off–on” graphene oxide wrapped mesoporous silica nanoparticles
Authors: Tang Yuxia , Hu Hao , Zhang Molly Gu , Song Jibin , Nie Liming , Wang Shouju , Niu Gang , Huang Peng , Lu Guangming , Chen Xiaoyuan
Published: March 2015

A photoresponsive drug delivery system was developed for light-mediated drug release and aptamer-targeted cancer therapy.
A study of the solvent effect on the crystal morphology of hexogen by means of molecular dynamics simulations
Authors: Chen Gang , Chen Chunyu , Xia Mingzhu , Lei Wu , Wang Fengyun , Gong Xuedong
Published: March 2015

In this work, molecular dynamics simulations have been performed to study the solvent effect on the crystal morphology of hexogen.
Determination of multi-class antimicrobial residues in soil by liquid chromatography-tandem mass spectrometry
Authors: Bian Kui , Liu YaHong , Wang ZongNan , Zhou Tong , Song XuQin , Zhang FangYu , He LiMin
Published: March 2015

Antimicrobial residues in environmental matrices may result in the occurrence of antimicrobial-resistant bacteria in soil.
Molecular insight into the mode-of-action of phosphonate monolayers as active functions of hybrid metal oxide adsorbents. Case study in sequestration of rare earth elements
Authors: Seisenbaeva Gulaim A. , Melnyk Inna V. , Hedin Niklas , Chen Yang , Eriksson Philip , Trzop Elżbieta , Zub Yuriy L. , Kessler Vadim G.
Published: March 2015

Organic–inorganic hybrid adsorbents for separation of rare earth elements were prepared by grafting of amino phosphonic acid ligands onto mesoporous TiO2. Their structure and capacity were elucidated using X-ray studies of molecular model compounds.
Physicochemical studies on local anaesthetic loaded second generation nanolipid carriers
Authors: Nahak Prasant , Karmakar Gourab , Roy Biplab , Guha Pritam , Sapkota Manish , Koirala Suraj , Chang Chien-Hsiang , Panda Amiya Kumar
Published: March 2015

Effect of drug concentration on different properties of NLC.
Control of plugging in bifunctional periodic mesoporous organosilica with imidazolium framework (BFPMO) via stepwise addition of silica precursors
Authors: Karimi Babak , Khorasani Mojtaba , Vali Hojatollah , Luque Rafael
Published: March 2015

The synthesis of novel highly ordered plugged or normal bifunctional periodic mesoporous organosilicas (BFPMOs) with variable content of bridged IL-phenyl or -ethyl units has been described.
Fabrication of layered Ti3C2 with an accordion-like structure as a potential cathode material for high performance lithium–sulfur batteries
Authors: Zhao Xiaoqin , Liu Min , Chen Yong , Hou Bo , Zhang Na , Chen Binbin , Yang Ning , Chen Ke , Li Jianlin , An Linan
Published: March 2015

L-Ti3C2 was prepared by exfoliating Ti3AlC2 in 40% HF. With sulfur-loaded L-Ti3C2 as cathodes, Li–S batteries deliver a high initial discharge capacity of 1291 mA h g−1, an excellent capacity retention of 970 mA h g−1 and coulombic efficiency of 99% after 100 cycles.
Green synthesis of a bromocresol purple/graphene composite and its application in electrochemical determination of 2,4,6-trichlorophenol
Authors: Zhu Xiaolin , Liu Jiguang , Zhang Zeshi , Lu Nan , Yuan Xing , Wu Dongmei
Published: March 2015

A poly(bromocresol purple)/electrochemically reduced graphene oxide composite film modified glassy carbon electrode was developed for the sensitive determination of 2,4,6-trichlorophenol without any pretreatment.
One-pot synthesis of doxorubicin-loaded multiresponsive nanogels based on hyperbranched polyglycerol
Authors: Sousa-Herves Ana , Wedepohl Stefanie , Calderón Marcelo
Published: March 2015

Doxorubicin-loaded nanogels with multiresponsive properties are prepared in a single step using hyperbranched polyglycerol as a biocompatible scaffold.
Two series of pH-dependent lanthanide complexes showing solvent-induced single crystal to single crystal transformation, sorption and luminescence properties
Authors: Zhang Lina , Zhang Chao , Zhang Bin , Du Chenxia , Hou Hongwei
Published: March 2015

Two series of new lanthanide PCPs were produced under different pH values. Series B demonstrates fascinating solvent-induced dynamic behaviors in an SCSC manner.
Modeling the local potential at Pt nanoparticles in polymer electrolyte membranes
Authors: Eslamibidgoli Mohammad Javad , Melchy Pierre-Éric Alix , Eikerling Michael H.
Published: March 2015

We present a physical–analytical model for the potential distribution at Pt nanodeposits in a polymer electrolyte membrane (PEM).
A metric for evaluation of the image quality of chemical maps derived from LA-ICP-MS experiments
Authors: Bonta Maximilian , Limbeck Andreas , Quarles Jr C. Derrick , Oropeza Dayana , Russo Richard E. , Gonzalez Jhanis J.
Published: March 2015

The quality of LA-ICP-MS images can be determined using a metric describing the accordance of measured and actual elemental distribution.
Preparation of adenovirus-templated gold nanoshells and a study of their photothermal therapy efficacy
Authors: Xue Weili , Zhou Jing , Gao Dawei , Gao Faming , Wang Zi , Luo Liyao , Li Yanji , Liu Zhiwei
Published: March 2015

Adenovirus-templated gold nanoshells not only show good biocompatibility but also have excellent photothermal therapy efficacy against tumors.
High strain epoxy shape memory polymer
Authors: Zheng Ning , Fang Guangqiang , Cao Zhengli , Zhao Qian , Xie Tao
Published: March 2015

Epoxy polymers represent a recently emerged class of thermoset shape memory polymers with superior thermo-mechanical endurance and excellent processability.
Enantioselective synthesis of 4,5,6,7-tetrahydroindoles via olefin cross-metathesis/intramolecular Friedel–Crafts alkylation reaction of pyrroles
Authors: Zhang Jun-Wei , Liu Xiao-Wei , Gu Qing , Shi Xiao-Xin , You Shu-Li
Published: March 2015

A sequential catalysis involving olefin cross-metathesis/asymmetric intramolecular Friedel–Crafts alkylation of pyrrole derivatives has been developed.
Concentration-dependent effective attractions between PEGylated nanoparticles
Authors: Oskolkova Malin Zackrisson , Stradner Anna , Ulama Jeanette , Bergenholtz Johan
Published: March 2015

Effective attractions between colloidal particles bearing a grafted PEG layer in water have been studied and, from a quantitative SANS analysis, are found to be concentration dependent.
Copper(i)/Lewis acid triggered ring-opening coupling reaction of cyclopropenes with nitriles
Authors: Huang Huawen , Ji Xiaochen , Xiao Fuhong , Deng Guo-Jun
Published: March 2015

A ring-opening coupling reaction of D–A cyclopropenes and nitriles is described for the facile synthesis of γ-amino ketones.
Surface characteristics, corrosion resistance and MG63 osteoblast-like cells attachment behaviour of nano SiO2–ZrO2 coated 316L stainless steel
Authors: Srinivasan Arthanari , Rajendran Nallaiyan
Published: March 2015

Nano ceramic coatings were produced on to 316L SS. MG-63 osteoblast like cells attachments were good for silica containing coatings.
Adsorption of chlorinated phenols on multiwalled carbon nanotubes
Authors: Kragulj Marijana , Tričković Jelena , Kukovecz Ákos , Jović Branislav , Molnar Jelena , Rončević Srđan , Kónya Zoltán , Dalmacija Božo
Published: March 2015

This work studies the adsorption of four chlorinated phenols (2,4-dichlorophenol, 2,4,6-trichlorophenol, 2,3,4,5-tetrachlorophenol and pentachlorophenol) in aqueous solutions on multiwalled carbon nanotubes (MWCNT).
Mechanism and selectivity of the dinuclear iron benzoyl-coenzyme A epoxidase BoxB
Authors: Liao Rong-Zhen , Siegbahn Per E. M.
Published: March 2015

DFT calculations are used to elucidate the reaction mechanism and selectivity of BoxB catalyzed benzoyl-CoA epoxidation.
Light-induced deformation of polymer networks containing azobenzene chromophores and liquid crystalline mesogens
Authors: Petrova Tatiana , Toshchevikov Vladimir , Saphiannikova Marina
Published: March 2015

We develop the theory of photo-deformations in two-component polymer networks containing liquid crystalline mesogens and azobenzene chromophores. Reorientation of azobenzenes under light irradiation is shown to be the driving force of material deformation.
Inhomogeneous relaxation dynamics and phase behaviour of a liquid crystal confined in a nanoporous solid
Authors: Całus Sylwia , Kityk Andriy V. , Eich Manfred , Huber Patrick
Published: March 2015

Dielectric spectroscopy reveals a radial partitioning in the structure and dynamics of a thermotropic liquid crystal confined in silica nanochannels.
Zinc-doped SnO2 nanocrystals as photoanode materials for highly efficient dye-sensitized solar cells
Authors: Li Xiaochao , Yu Qingjiang , Yu Cuiling , Huang Yuewu , Li Renzhi , Wang Jinzhong , Guo Fengyun , Zhang Yong , Gao Shiyong , Zhao Liancheng
Published: March 2015

Dye-sensitized solar cells based on Zn-doped SnO2 nanocrystal photoanodes have achieved a remarkable power conversion efficiency of 8.23%.
Selective etching of metastable phase induced an efficient CuIn0.7Ga0.3S2nano-photocathode for solar water splitting
Authors: Guan Zhongjie , Luo Wenjun , Feng Jianyong , Tao Qiuchen , Xu Yao , Wen Xin , Fu Gao , Zou Zhigang
Published: March 2015

The photocurrent of a CuIn0.7Ga0.3S2nano-photocathode increases about 2–3 times after selective etching of a metastable CuAu ordering phase.
Stereo matching based on segmented B‐spline surface fitting and accelerated region belief propagation
Authors: Huang Jingzhou
Published: March 2015

The authors propose a new stereo matching algorithm based on an iterative optimisation framework including bi‐cubic B‐spline surface fitting and accelerated region belief propagation (BP). They first compute the initial cost and disparity map by the adaptive support‐weight approach and then launch the iterative process in which the disparity space image is refined via the bi‐cubic B‐spline fitting and optimised via the accelerated region BP. Two innovations are contained in the algorithm: (i) disparity space image refinement based on segmented bi‐cubic B‐spline surface fitting; and (ii) an accelerated region message passing approach for BP. The algorithm is verified on the Middlebury benchmark and experimental results show the algorithm is effective and achieves the state‐of‐the‐art accuracy.
Magnetization in AIIIBV semiconductor heterostructures with the depletion layer of manganese
Authors: Charikova T. , Okulov V. , Gubkin A. , Lugovikh A. , Moiseev K. , Nevedomsky V. , Kudriavtsev Yu. , Gallardo S. , Lopez M.
Published: March 2015

The magnetic moment and magnetization in GaAs/Ga0.84In0.16As/GaAs heterostructures with Mn diluted in GaAs cover layers and with atomically controlled Mn δ-layer thicknesses near GaInAs-quantum well (∼3 nm) in temperature range T = 1.8–300 K in magnetic field up to 50 kOe have been investigated. The mass magnetization all of the samples of GaAs/Ga0.84In0.16As/GaAs with Mn increases with the increasing of the magnetic field that pointed out on the presence of low-dimensional ferromagnetism in the manganese depletion layer of GaAs based structures. It has been estimated the manganese content threshold at which the ferromagnetic ordering was found.
Quantum Hall plateau-plateau transitions in n-InGaAs/GaAs heterostructures before and after IR illumination
Authors: Arapov Yu. G. , Gudina S. V. , Klepikova A. S. , Neverov V. N. , Harus G. I. , Shelushinina N. G. , Yakunin M. V.
Published: March 2015

The longitudinal ρxx(B,T) and Hall ρxy(B,T) magnetoresistances in n-InGaAs/GaAs heterostructures with a single quantum well are studied experimentally before and after IR illumination in the quantum Hall regime in magnetic fields B = 0–12 T and at temperatures T = 0.4–4.2 K. The temperature dependence of the width of quantum Hall plateau-plateau transitions is analyzed in terms of a two-parameter scaling theory.
Electron transport and low-temperature electrical and galvanomagnetic properties of zinc oxide and indium oxide films
Authors: Kulbachinskii V. A. , Kytin V. G. , Reukova O. V. , Burova L. I. , Kaul A. R. , Ulyashin A. G.
Published: March 2015

The electrical and galvanomagnetic properties of zinc oxide films with and without gallium, aluminum, and cobalt doping and of tin-doped indium oxide films are studied over a wide range of temperatures and magnetic fields. It is shown that the mechanism for electron transport in these films changes from band to hopping transport as the degree of crystallinity of the films is reduced because of the methods and conditions for their synthesis. The change in the dimensionality of the films with band electron transport at low temperatures is studied in terms of the weak localization induced by a magnetic field. The localization radius and density of electron states in the Fermi level are estimated for the films with a hopping electron transport.
Spin ordering contribution of iron, cobalt, and nickel impurity electron states, to the low-temperature magnetic susceptibility of mercury selenide crystals
Authors: Govorkova T. E. , Lonchakov A. T. , Okulov V. I. , Andriichuk M. D. , Gubkin A. F. , Paranchich L. D.
Published: March 2015

A study of the magnetic susceptibility of electron systems of hybridized states of iron, cobalt, and nickel impurities in mercury selenide crystals at low temperatures, in connection with newly discovered evidence of spontaneous spin polarization in the anomalous Hall effect, at room temperature. It is shown that in the measured paramagnetic susceptibility of electrons in hybridized states, there exists a temperature-independent portion, and that there is enough justification to identify it using spontaneous polarization. The other portion demonstrates the Curie law with decreasing temperature, and corresponds to contributions from nonpolarized electrons. Based on findings relating to the magnetization of the examined impurity systems, we identify a part of the spontaneously polarized electron density in the localized component of hybridized states. We give quantitative estimates of the aforementioned portions of each impurity.
A magnetic stirring setup for applications in ultrafast spectroscopy of photo-sensitive solutions
Authors: Dominguez Pablo Nahuel , Lehner Florian T. , Michelmann Jeff , Himmelstoss Matthias , Zinth Wolfgang
Published: March 2015

An exchange system is presented, which allows ultrafast experiments with high excitation rates (1 kHz) on samples with reaction cycles in the range of a few seconds and small sample volumes of about 0.3 ml. The exchange is accomplished using a commercially available cuvette by the combination of a special type of magnetic stirring with transverse translational motion of the sample cuvette.
Quantum transport through a multilevel magnetic structure with multiple inelastic scattering in a magnetic field taken into account
Authors: Val'kov V. V. , Aksenov S. V. , Ulanov E. A.
Published: March 2015

We present a solution for the problem of quantum electron transport through a magnetic atom adsorbed inside a break junction with paramagnetic metal electrodes. In agreement with experimental data, it was assumed that the conduction electrons experience inelastic scattering by the adsorbate due to s–d(f)-exchange interaction. The Keldysh technique was employed to obtain a general expression describing a current through the multilevel structure at finite temperatures in terms of the nonequilibrium Green's function. The use of the atomic representation allowed to exactly account for the non-equidistant structure of the energy spectrum of a magnetic atom and to simplify substantially the application of the Wick theorem for construction of the nonequilibrium diagrammatic technique for the Hubbard operators. The calculation of the current-voltage characteristics of the magnetic adatom in the tunnel regime at low temperatures revealed the presence of regions with a negative differential conductance in a magnetic field.
Lattice simulation method to model diffusion and NMR spectra in porous materials
Authors: Merlet Céline , Forse Alexander C. , Griffin John M. , Frenkel Daan , Grey Clare P.
Published: March 2015

A coarse-grained simulation method to predict nuclear magnetic resonance (NMR) spectra of ions diffusing in porous carbons is proposed. The coarse-grained model uses input from molecular dynamics simulations such as the free-energy profile for ionic adsorption, and density-functional theory calculations are used to predict the NMR chemical shift of the diffusing ions. The approach is used to compute NMR spectra of ions in slit pores with pore widths ranging from 2 to 10 nm. As diffusion inside pores is fast, the NMR spectrum of an ion trapped in a single mesopore will be a sharp peak with a pore size dependent chemical shift. To account for the experimentally observed NMR line shapes, our simulations must model the relatively slow exchange between different pores. We show that the computed NMR line shapes depend on both the pore size distribution and the spatial arrangement of the pores. The technique presented in this work provides a tool to extract information about the spatial distribution of pore sizes from NMR spectra. Such information is difficult to obtain from other characterisation techniques.
Spin and charge effects due to positively charged acceptors in GaAs/AlGaAs quantum wells
Authors: Petrov P. V. , Ivanov Yu. L. , Averkiev N. S.
Published: March 2015

We present the results of optical measurements on the structures containing GaAs/AlGaAs quantum wells with positively charged acceptors (A+ centers). The data on the spin structure and localization of the A+ centers in the 2D system were obtained using magneto-optical measurements. The energy structure of the A+ impurity band was studied using the temperature dependence of photoluminescence. Based on the analysis of the complete set of experimental data obtained by different optical methods and their comparison with the results of transport measurements reported in literature, we developed a unified physical picture of charge and spin phenomena in such systems. A new experimental method, based on the measurements of photoexcitation and photoluminescence spectra, is proposed for studies of the Coulomb gap appearing at low temperatures in the density of localized states.
Superelastic collisions under low temperature plasma and afterglow conditions: A golden rule to estimate their quantitative effects
Authors: D'Ammando Giuliano , Colonna Gianpiero , Capitelli Mario , Laricchiuta Annarita
Published: March 2015

A simple equation describing the formation of plateaux induced by superelastic collisions in the electron energy distribution function (EEDF) of low temperature and afterglow plasmas is derived. The EEDFs predicted from this equation are in good agreement with those obtained from the numerical solution of the full Boltzmann equation in the presence of excited states.
What parameters can be reliably deduced from the current-voltage characteristics of an organic bulk-heterojunction solar cell?
Authors: Set Ying Ting , Zhang Teng , Birgersson Erik , Luther Joachim
Published: March 2015

Through the analysis of scales and simplification of the drift-diffusion device model, we have obtained a quantitative description of the mechanisms underlying the current-voltage (j–V) characteristics of organic bulk-heterojunction solar cells. The mechanisms have been resolved into the competition between the photogeneration, recombination, and extraction/injection rates, which determines the bulk charge carrier concentration; and the combined effect of the built-in field and the boundary layers in shaping the electric potential distribution, which determines the bulk field. The relationships between the j–V characteristics and standard model parameters have been captured with analytical expressions and verified through 1-D numerical simulations. We have determined that while the charge carrier generation rate can be reliably extracted with the device model from j–V measurements alone, the effective density of states and built-in potential, and the mobility and recombination prefactor are clustered pairs that can only be decoupled through other characterization techniques.
Effect of the crystallinity of silver nanoparticles on surface plasmon resonance induced enhancement of effective absorption cross-section of dyes
Authors: Tanvi  , Mahajan Aman , Bedi R. K. , Kumar Subodh , Saxena Vibha , Aswal D. K.
Published: March 2015

The effective absorption cross-section of dye, and therefore, the efficiency of dye-sensitized solar cell can be increased by surface plasmon resonance (SPR) of metal nanoparticles with enhanced dephasing time. Further, the dephasing time is proportional to the enhancement factor of electric field in the vicinity of nanoparticle surface, and is governed by size, shape, and dielectric constant of surrounding medium. In this paper, we demonstrate that crystallinity of silver nanoparticles plays an important role in enhancing the dephasing time of SPR. Our theoretical formulation indicates that the dephasing time is higher for single crystalline silver nanoparticles as compared to that of polycrystalline nanoparticles, which is attributed to the presence of scattering centers in the latter. This suggests that single crystalline silver nanoparticles are interesting candidates for the enhancement of effective absorption cross-section of dyes. In order to validate our theoretical formulation, we have synthesized single crystalline and polycrystalline silver nanoparticles and studied their effect on absorption cross-section of N719 dye. We observed that dye incorporated with single crystalline silver nanoparticles showed a significant enhancement as compared to polycrystalline silver nanoparticles (24.42% in solution, 21.01% in thin film form in single crystalline silver nanoparticles while 8.52% in solution, 7.97% in thin film form in polycrystalline silver nanoparticles, respectively).
Asymmetric asynchrony of financial time series based on asymmetric multiscale cross-sample entropy
Authors: Yin Yi , Shang Pengjian
Published: March 2015

The paper proposes the asymmetric multiscale cross-sample entropy (AMCSE) method and applies it to analyze the financial time series of US, Chinese, and European stock markets. The asynchronies of these time series in USA, China, and Europe all decrease (the correlations increase) with the increase in scale which declares that taking into account bigger time scale to study these financial time series is capable of revealing the intrinsic relations between these stock markets. Meanwhile, we find that there is a crossover between the upwards and the downwards in these AMCSE results, which indicates that when the scale reach a certain value, the asynchronies of the upwards and the downwards for these stock markets are equal and symmetric. But for the other scales, the asynchronies of the upwards and the downwards are different from each other indicating the necessity and importance of multiscale analysis for revealing the most comprehensive information of stock markets. The series with a positive trend have a higher decreasing pace on asynchrony than those with a negative trend, while the asynchrony between the series with a positive or negative trend is lower than that between the original series. Moreover, it is noticeable that there are some small abnormal rises at some abnormal scales. We find that the asynchronies are the highest at scales smaller than 2 when investigating the time series of stock markets with a negative trend. The existences of asymmetries declare the inaccuracy and weakness of multiscale cross-sample entropy, while by comparing the asymmetries of US, Chinese, and European markets, similar conclusions can be drawn and we acquire that the asymmetries of Chinese markets are the smallest and the asymmetries of European markets are the biggest. Thus, it is of great value and benefit to investigate the series with different trends using AMCSE method.
Realization of a reversible switching in TaO2 polymorphs via Peierls distortion for resistance random access memory
Authors: Zhu Linggang , Zhou Jian , Guo Zhonglu , Sun Zhimei
Published: March 2015

Transition-metal-oxide based resistance random access memory (RRAM) is a promising candidate for next-generation universal non-volatile memories. Searching and designing appropriate materials used in the memories becomes an urgent task. Here, a structure with the TaO2 formula was predicted using evolutionary algorithms in combination with first-principles calculations. This triclinic structure (T-TaO2) is both energetically and dynamically more favorable than the commonly believed rutile structure (R-TaO2). The metal-insulator transition (MIT) between metallic R-TaO2 and T-TaO2 (band gap: 1.0 eV) is via a Peierls distortion, which makes TaO2 a potential candidate for RRAM. The energy barrier for the reversible phase transition is 0.19 eV/atom and 0.23 eV/atom, respectively, suggesting low power consumption for the resistance switch. The present findings about the MIT as the resistance-switch mechanism in Ta-O system will stimulate experimental work to fabricate tantalum oxides based RRAM.
Optically switchable natural silk
Authors: Krasnov Igor , Krekiehn Nicolai R. , Krywka Christina , Jung Ulrich , Zillohu Ahnaf U. , Strunskus Thomas , Elbahri Mady , Magnussen Olaf M. , Müller Martin
Published: March 2015

An optically active bio-material is created by blending natural silk fibers with photoisomerizable chromophore molecules—azobenzenebromide (AzBr). The material converts the energy of unpolarized light directly into mechanical work with a well-defined direction of action. The feasibility of the idea to produce optically driven microsized actuators on the basis of bio-material (silk) is proven. The switching behavior of the embedded AzBr molecules was studied in terms of UV/Vis spectroscopy. To test the opto-mechanical properties of the modified fibers and the structural changes they undergo upon optically induced switching, single fiber X-ray diffraction with a micron-sized synchrotron radiation beam was combined in situ with optical switching as well as with mechanical testing and monitoring. The crystalline regions of silk are not modified by the presence of the guest molecules, hence occupy only the amorphous part of the fibers. It is shown that chromophore molecules embedded into fibers can be reversibly switched between the trans and cis conformation by illumination with light of defined wavelengths. The host fibers respond to this switching with a variation of the internal stress. The amplitude of the mechanical response is independent of the applied external stress and its characteristic time is shorter than the relaxation time of the usual mechanical response of silk.
Bonded cylindrical Terfenol-D-epoxy/PZT magnetoelectric composites prepared by the one-step compression molding
Authors: Song Yang , Pan De’an , Wang Jiao , Zuo Zhijun , Zhang Shengen , Liu Bo , Volinsky Alex A.
Published: March 2015

Magnetoelectric composites with bonded Terfenol-D-epoxy (TDE) and PZT cylindrical ceramics were prepared by the one-step compression molding at room temperature. The PZT cylindrical ceramics not only provided the piezoelectric phase, but also acted as a mold for TDE. The axial ME voltage coefficient of the cylindrical composites, αE,A, was studied. By contrast, the new structure has a larger ME voltage coefficient compared with the effective planar laminated composites due to the self-bound state. This study decreases the ME composite dimensions, making it a promising candidate for the magnetic field sensor applications.
Molecular vibrations offer control over electron transfer
Authors: Miller Johanna L.
Published: March 2015

A targeted low-energy excitation can dramatically alter the course of charge separation in a molecule.
Remote makeovers maximize return on spacecraft science
Authors: Feder Toni
Published: March 2015

Altered trajectories, spare or repurposed instruments, new software, and other clever tactics can give spacecraft a new lease on life.