bluuebunny/crossref_metadata_2025 huggingface dataset:
A phylo-functional core of gut microbiota in healthy young Chinese cohorts across lifestyles, geography and ethnicities
Authors: Zhang Jiachao , Guo Zhuang , Xue Zhengsheng , Sun Zhihong , Zhang Menghui , Wang Lifeng , Wang Guoyang , Wang Fang , Xu Jie , Cao Hongfang , Xu Haiyan , Lv Qiang , Zhong Zhi , Chen Yongfu , Qimuge Sudu , Menghe Bilige , Zheng Yi , Zhao Liping , Chen Wei , Zhang Heping
Published: February 2015

Structural profiling of healthy human gut microbiota across heterogeneous populations is necessary for benchmarking and characterizing the potential ecosystem services provided by particular gut symbionts for maintaining the health of their hosts. Here we performed a large structural survey of fecal microbiota in 314 healthy young adults, covering 20 rural and urban cohorts from 7 ethnic groups living in 9 provinces throughout China. Canonical analysis of unweighted UniFrac principal coordinates clustered the subjects mainly by their ethnicities/geography and less so by lifestyles. Nine predominant genera, all of which are known to contain short-chain fatty acid producers, co-occurred in all individuals and collectively represented nearly half of the total sequences. Interestingly, species-level compositional profiles within these nine genera still discriminated the subjects according to their ethnicities/geography and lifestyles. Therefore, a phylogenetically diverse core of gut microbiota at the genus level may be commonly shared by distinctive healthy populations as functionally indispensable ecosystem service providers for the hosts.
Humans perceive flicker artifacts at 500 Hz
Authors: Davis James , Hsieh Yi-Hsuan , Lee Hung-Chi
Published: February 2015

Humans perceive a stable average intensity image without flicker artifacts when a television or monitor updates at a sufficiently fast rate. This rate, known as the critical flicker fusion rate, has been studied for both spatially uniform lights and spatio-temporal displays. These studies have included both stabilized and unstablized retinal images and report the maximum observable rate as 50–90 Hz. A separate line of research has reported that fast eye movements known as saccades allow simple modulated LEDs to be observed at very high rates. Here we show that humans perceive visual flicker artifacts at rates over 500 Hz when a display includes high frequency spatial edges. This rate is many times higher than previously reported. As a result, modern display designs which use complex spatio-temporal coding need to update much faster than conventional TVs, which traditionally presented a simple sequence of natural images.
Using Bayesian modelling to investigate factors governing antibiotic-induced Candida albicans colonization of the GI tract
Authors: Shankar Jyoti , Solis Norma V. , Mounaud Stephanie , Szpakowski Sebastian , Liu Hong , Losada Liliana , Nierman William C. , Filler Scott G.
Published: February 2015

Receipt of broad-spectrum antibiotics enhances Candida albicans colonization of the GI tract, a risk factor for haematogenously-disseminated candidiasis. To understand how antibiotics influence C. albicans colonization, we treated mice orally with vancomycin or a combination of penicillin, streptomycin and gentamicin (PSG) and then inoculated them with C. albicans by gavage. Only PSG treatment resulted in sustained, high-level GI colonization with C. albicans. Furthermore, PSG reduced bacterial diversity in the colon much more than vancomycin. Both antibiotic regimens significantly reduced IL-17A, IL-21, IL-22 and IFN-γ mRNA levels in the terminal ileum but had limited effect on the GI fungal microbiome. Through a series of models that employed Bayesian model averaging, we investigated the associations between antibiotic treatment, GI microbiota and host immune response and their collective impact on C. albicans colonization. Our analysis revealed that bacterial genera were typically associated with either C. albicans colonization or altered cytokine expression but not with both. The only exception was Veillonella, which was associated with both increased C. albicans colonization and reduced IL-21 expression. Overall, antibiotic-induced changes in the bacterial microbiome were much more consistent determinants of C. albicans colonization than either the GI fungal microbiota or the GI immune response.
Protein evolution analysis of S-hydroxynitrile lyase by complete sequence design utilizing the INTMSAlign software
Authors: Nakano Shogo , Asano Yasuhisa
Published: February 2015

Development of software and methods for design of complete sequences of functional proteins could contribute to studies of protein engineering and protein evolution. To this end, we developed the INTMSAlign software and used it to design functional proteins and evaluate their usefulness. The software could assign both consensus and correlation residues of target proteins. We generated three protein sequences with S-selective hydroxynitrile lyase (S-HNL) activity, which we call designed S-HNLs; these proteins folded as efficiently as the native S-HNL. Sequence and biochemical analysis of the designed S-HNLs suggested that accumulation of neutral mutations occurs during the process of S-HNLs evolution from a low-activity form to a high-activity (native) form. Taken together, our results demonstrate that our software and the associated methods could be applied not only to design of complete sequences, but also to predictions of protein evolution, especially within families such as esterases and S-HNLs.
Identification of flubendazole as potential anti-neuroblastoma compound in a large cell line screen
Authors: Michaelis Martin , Agha Bishr , Rothweiler Florian , Löschmann Nadine , Voges Yvonne , Mittelbronn Michel , Starzetz Tatjana , Harter Patrick N. , Abhari Behnaz A. , Fulda Simone , Westermann Frank , Riecken Kristoffer , Spek Silvia , Langer Klaus , Wiese Michael , Dirks Wilhelm G. , Zehner Richard , Cinatl Jaroslav , Wass Mark N. , Cinatl Jindrich
Published: February 2015

Flubendazole was shown to exert anti-leukaemia and anti-myeloma activity through inhibition of microtubule function. Here, flubendazole was tested for its effects on the viability of in total 461 cancer cell lines. Neuroblastoma was identified as highly flubendazole-sensitive cancer entity in a screen of 321 cell lines from 26 cancer entities. Flubendazole also reduced the viability of five primary neuroblastoma samples in nanomolar concentrations thought to be achievable in humans and inhibited vessel formation and neuroblastoma tumour growth in the chick chorioallantoic membrane assay. Resistance acquisition is a major problem in high-risk neuroblastoma. 119 cell lines from a panel of 140 neuroblastoma cell lines with acquired resistance to various anti-cancer drugs were sensitive to flubendazole in nanomolar concentrations. Tubulin-binding agent-resistant cell lines displayed the highest flubendazole IC50and IC90values but differences between drug classes did not reach statistical significance. Flubendazole induced p53-mediated apoptosis. The siRNA-mediated depletion of the p53 targets p21, BAX, or PUMA reduced the neuroblastoma cell sensitivity to flubendazole with PUMA depletion resulting in the most pronounced effects. The MDM2 inhibitor and p53 activator nutlin-3 increased flubendazole efficacy while RNAi-mediated p53-depletion reduced its activity. In conclusion, flubendazole represents a potential treatment option for neuroblastoma including therapy-refractory cells.
Angiotensin-converting enzyme 2/angiotensin-(1–7)/Mas axis prevents lipopolysaccharide–induced apoptosis of pulmonary microvascular endothelial cells by inhibiting JNK/NF–κB pathways
Authors: Li Yingchuan , Cao Yongmei , Zeng Zhen , Liang Mengfan , Xue Ying , Xi Caihua , Zhou Ming , Jiang Wei
Published: February 2015

ACE2 and Ang–(1–7) have important roles in preventing acute lung injury. However, it is not clear whether upregulation of the ACE2/Ang–(1–7)/Mas axis prevents LPS–induced injury in pulmonary microvascular endothelial cells (PMVECs) by inhibiting the MAPKs/NF–κB pathways. Primary cultured rat PMVECs were transduced with lentiviral–borne Ace2 or shRNA–Ace2 and then treated or not with Mas receptor blocker (A779) before exposure to LPS. LPS stimulation resulted in the higher levels of AngII, Ang–(1–7), cytokine secretion and apoptosis rates and the lower ACE2/ACE ratio. Ace2 reversed the ACE2/ACE imbalance and increased Ang–(1–7) levels, thus reducing LPS–induced apoptosis and inflammation, while inhibition of Ace2 reversed all these effects. A779 abolished these protective effects of Ace2. LPS treatment was associated with activation of the ERK, p38, JNK and NF–κB pathways, which were aggravated by A779. Pretreatment with A779 prevented the Ace2–induced blockade of p38, JNK and NF–κB phosphorylation. However, only JNK inhibitor markedly reduced apoptosis and cytokine secretion in PMVECs with Ace2 deletion and A779 pretreatment. These results suggest that the ACE2/Ang–(1–7)/Mas axis has a crucial role in preventing LPS–induced apoptosis and inflammation of PMVECs, by inhibiting the JNK/NF–κB pathways.
A multiple amplification strategy for nucleic acid detection based on host–guest interaction between the β-cyclodextrin polymer and pyrene
Authors: Guo Xiaochen , Liu Pei , Yang Xiaohai , Wang Kemin , Wang Qing , Guo Qiuping , Huang Jin , Liu Jianbo , Song Chunxia , Li Wenshan
Published: February 2015

The proposed multiple amplification strategy based on the excellent fluorescence enhancement capability of β-CDP for pyrene is facile, sensitive and rapid.
A cysteine sensor based on a gold nanoparticle–iron phthalocyanine modified graphite paste electrode
Authors: Abbas Mohammed Nooredeen , Saeed Ayman Ali , Singh Baljit , Radowan Abdellatef A. , Dempsey Eithne
Published: February 2015

An electrochemical sensor for the sensitive and selective detection of cysteine is proposed based on a gold nanoparticle (AuNP)–iron(iii) phthalocyanine (FePc) modified graphite paste electrode.
Iron oxide cluster induced barrier-free conversion of nitric oxide to ammonia
Authors: Takahashi Keisuke
Published: February 2015

Nitrogen oxide (NO) conversion to ammonia (NH3) over iron oxide clusters is investigated using density functional theory calculations.
Colour-tunable fluorescence of single molecules based on the vibration induced emission of phenazine
Authors: Huang Wei , Sun Lu , Zheng Zhiwen , Su Jianhua , Tian He
Published: February 2015

Combining the vibration of the phenazine unit (S0) and the intramolecular energy transfer (IET) effect, compound M1–M4 exhibited color-tunable fluorescence even white emission in two different ways.
Visible light promoted thiol-ene reactions using titanium dioxide
Authors: Bhat Venugopal T. , Duspara Petar A. , Seo Sangwon , Abu Bakar Nor Syazwani Binti , Greaney Michael F.
Published: February 2015

Thiol-ene chemistry under mild conditions is reported using titania as a cheap and user-friendly photoredox catalyst.
A facile strategy to generate polymeric nanoparticles for synergistic chemo-photodynamic therapy
Authors: Deng Xin , Liang Yan , Peng Xinyu , Su Ting , Luo Song , Cao Jun , Gu Zhongwei , He Bin
Published: February 2015

Polymeric nanoparticles generated by mPEG-tetrakis(4-carboxyphenyl)porphyrin amphiphiles were used to trap doxorubicin for synergistic chemo-photodynamic therapy.
Supersaturation-induced hydrothermal formation of α-CaSO4·0.5H2O whiskers
Authors: Hou S. C. , Wang J. , Xue T. Y. , Zheng W. J. , Xiang L.
Published: February 2015

Supersaturation-induced fast transformation from CaSO4·2H2O to α-CaSO4·0.5H2O was observed and the process followed the dissolution–precipitation and homogeneous nucleation mechanism according to classical nucleation theory.
Up-conversion luminescence properties of lanthanide-doped LuF3 with different morphologies synthesized via a facile ionothermal process
Authors: Yu Xue , Bian Wenjuan , Wang Ting , Zhou Dacheng , Qiu Jianbei , Xu Xuhui
Published: February 2015

Up-conversion (UC) crystals of lanthanide-doped LuF3 with different morphologies (nanoparticles, shuttle- and litchi-like microcrystals) have been synthesized via a facile ionothermal method.
The role of molecular oxygen in the iron(iii)-promoted oxidative dehydrogenation of amines
Authors: Saucedo-Vázquez Juan Pablo , Kroneck Peter M. H. , Sosa-Torres Martha Elena
Published: February 2015

A mechanistic study is presented of the oxidative dehydrogenation of the iron(iii) complex [FeIIIL3]3+,1, (L3= 1,9-bis(2′-pyridyl)-5-[(ethoxy-2′′-pyridyl)methyl]-2,5,8-triazanonane) in ethanol in the presence of molecular oxygen.
Solvatochromic and application in dye-sensitized solar cells of sandwich-like Cd(ii) complexes: supramolecular architectures based on N1,N3-bis[(6-methoxypyridin-2-yl)methylene]benzene-1,3-diamine
Authors: Wang Xin-Ming , Wang Ping , Fan Rui-Qing , Xu Meng-Ying , Qiang Liang-Sheng , Wei Li-Guo , Yang Yu-Lin , Wang Yu-Lei
Published: February 2015

Co-sensitizers 1 and 2 exhibited solvatochromism and fluorescence quenching behavior to CH3OH.
Surface-confined 2D polymerization of a brominated copper-tetraphenylporphyrin on Au(111)
Authors: Smykalla Lars , Shukrynau Pavel , Korb Marcus , Lang Heinrich , Hietschold Michael
Published: February 2015

A coupling-limited approach for the Ullmann reaction-like on-surface synthesis of a two-dimensional covalent organic network starting from a halogenated metallo-porphyrin is demonstrated.
A nano-grid structure made of perovskite SrTiO3 nanowires for efficient electron transport layers in inverted polymer solar cells
Authors: Kim Jeong Won , Suh Yo-han , Lee Chang-Lyoul , Kim Yong Seok , Kim Won Bae
Published: February 2015

A nano-grid structure of perovskite SrTiO3 NWs is developed for a novel electron transport layer in inverted polymer solar cells.
Cobalt/polypyrrole nanocomposites with controllable electromagnetic properties
Authors: Wang Haicheng , Ma Ning , Yan Zhiran , Deng Ling , He Jun , Hou Yanglong , Jiang Yong , Yu Guanghua
Published: February 2015

Cobalt/polypyrrole nanocomposites for electromagnetic wave absorbents were prepared by in situ polymerization of pyrrole in the presence of Co nanoparticles. With different ratios of Co/polypyrrole, these nanocomposite materials can show controllable electromagnetic properties.
Size-dependent tuning of horseradish peroxidase bioreactivity by gold nanoparticles
Authors: Wu Haohao , Liu Yi , Li Meng , Chong Yu , Zeng Mingyong , Lo Y. Martin , Yin Jun-Jie
Published: February 2015

Here we report gold nanoparticles can size-dependently enhance or inhibit HRP bioreactivity toward substrates with different redox potentialsviaa mechanism involving extension of the HRP substrate access channel and decline in the redox potentials of HRP catalytic intermediates.
Metallic oxide nanoparticle translocation across the human bronchial epithelial barrier
Authors: George Isabelle , Naudin Grégoire , Boland Sonja , Mornet Stéphane , Contremoulins Vincent , Beugnon Karine , Martinon Laurent , Lambert Olivier , Baeza-Squiban Armelle
Published: February 2015

The translocation of inhaled NP can be evaluated using anin vitromodel of airway epithelial barrier and characterized according to their intrinsic properties.
Harmony of CdI2with CuBr for the one-pot synthesis of optically active α-allenols
Authors: Zhang Jiasheng , Ye Juntao , Ma Shengming
Published: February 2015

A highly efficient one-pot synthesis of chiral α-allenols from propargylic alcohols, aldehydes and pyrrolidine induced by CuBr and (R,Ra)-N-PINAP or (R,Sa)-N-PINAP and CdI2has been developed.
Pd-functionalized MCM-41 nanoporous silica as an efficient and reusable catalyst for promoting organic reactions
Authors: Nejat Razieh , Mahjoub Ali Reza , Hekmatian Zahra , Azadbakht Tahereh
Published: February 2015

Pd-functionalized MCM-41 nanoporous silica has been explored as an efficient and recyclable catalyst to effect Suzuki and Mizoroki–Heck cross-coupling reactions, under solvent-free conditions.
Facile synthesis and supercapacitive properties of Zr-metal organic frameworks (UiO-66)
Authors: Tan Yueyue , Zhang Wei , Gao Yilong , Wu Jianxiang , Tang Bohejin
Published: February 2015

A facile synthetic method was developed to prepare Zr-MOFs. Pseudocapacitor behavior in KOH electrolyte. Zr-MOF1 with small particle size exhibited higher supercapacitive performance.
Electronic and magnetic properties of an AlN monolayer doped with first-row elements: a first-principles study
Authors: Bai Yujie , Deng Kaiming , Kan Erjun
Published: February 2015

Two-dimensional (2D) magnetic materials are the focus of one of the most active areas of nano-materials research.
N-substituted defective graphene sheets: promising electrode materials for Na-ion batteries
Authors: Shen Hao , Rao Dewei , Xi Xiaoming , Liu Yuzhen , Shen Xiangqian
Published: February 2015

ViaDFT calculations, we theoretically demonstrated that the N doped defective structures are beneficial for Na adsorption and that the charge transfer can significantly influence the adsorption energies.
Metal–organic framework MIL-53(Fe): facile microwave-assisted synthesis and use as a highly active peroxidase mimetic for glucose biosensing
Authors: Dong Wenfei , Liu Xidong , Shi Wenbing , Huang Yuming
Published: February 2015

A microwave-based simple, fast and facile preparation of MIL-53(Fe) with an enhanced peroxidase-like activity for the highly sensitive and selective detection of glucose in real human serum samples was demonstrated.
Organosilicon functionalized glycerol carbonates as electrolytes for lithium-ion batteries
Authors: Wang Jinglun , Yong Tianqiao , Yang Jianwen , Ouyang Chuying , Zhang Lingzhi
Published: February 2015

Organosilicon functionalized glycerol carbonates were synthesized as an electrolyte solvent/additive for lithium-ion batteries.
Positively charged, surfactant-free gold nanoparticles for nucleic acid delivery
Authors: Guo Jianfeng , Armstrong Mark J. , O'Driscoll Caitriona M. , Holmes Justin D. , Rahme Kamil
Published: February 2015

Synthesis of positively charged, surfactant-free, not cytotoxic 2–200 nm gold nanoparticles in water by seeding growth method; a powerful candidate for nucleic acid delivery application.
Preparation of porous silica films in a binary template system for double-layer broadband antireflective coatings
Authors: Li Yuanyang , Lv Haibing , Ye Longqiang , Yan Lianghong , Zhang Yulu , Xia BiBo , Yan Hongwei , Jiang Bo
Published: February 2015

The double-layer coating has high transmittances over a broad wavelength region.
Development of solvent-free synthesis of hydrogen-bonded supramolecular polyurethanes
Authors: Houton Kelly. A. , Burslem George M. , Wilson Andrew. J.
Published: February 2015

A solvent free ball-milling method for the synthesis of small molecule and oligomeric carbamates is described that is applicable to supramolecular polymer synthesis.
Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar
Authors: Nichols B. , Chadwick H. , Gordon S. D. S. , Eyles C. J. , Hornung B. , Brouard M. , Alexander M. H. , Aoiz F. J. , Gijsbertsen A. , Stolte S.
Published: February 2015

New measurements of the differential steric effect for NO + Ar inelastic scattering highlight the importance of quantum interference.
Competitive formation of homocircuit [3]rotaxanes in synthetically useful yields in the bipyridine-mediated active template CuAAC reaction
Authors: Neal Edward A. , Goldup Stephen M.
Published: February 2015

We demonstrate that, depending on reaction conditions, [2]rotaxanes are produced in essentially quantitative yield in the AT-CuAAC reaction regardless of macrocycle size, and hard to access doubly threaded [3]rotaxanes can be synthesised in up to 50% isolated yield in a four component coupling step.
Carbon dots from PEG for highly sensitive detection of levodopa
Authors: Li Hao , Liu Juan , Guo Sijie , Zhang Yalin , Huang Hui , Liu Yang , Kang Zhenhui
Published: February 2015

Fluorescent carbon dots (CDs)/tyrosinase hybrid as a fluorescent probe for efficient, fast and sensitive detection of levodopa.
Molybdenum disulfide-based amplified fluorescence DNA detection using hybridization chain reactions
Authors: Huang Jiahao , Ye Lei , Gao Xiang , Li Hao , Xu Jianbin , Li Zhigang
Published: February 2015

A simple, sensitive, and selective amplified fluorescence DNA detection strategyviaenzyme-free molybdenum disulfide-assisted hybridization chain reactions.
CdSe/ZnS core–shell quantum dots charge trapping layer for flexible photonic memory
Authors: Han Su-Ting , Zhou Ye , Zhou Li , Yan Yan , Huang Long-Biao , Wu Wei , Roy V. A. L.
Published: February 2015

A novel design of UV-manipulated photonic nonvolatile memory based on spin-coated close-packed CdSe/ZnS quantum dots is reported.
Color-tunable and highly solid emissive AIE molecules: synthesis, photophysics, data storage and biological application
Authors: Li Shuhong , Shang Yanli , Zhao Engui , Kwok Ryan T. K. , Lam Jacky W. Y. , Song Yanlin , Tang Ben Zhong
Published: February 2015

Different color and highly emissive AIE molecules were constructed by tetraphenylene and dimesitylboron groups through CC bonds, demonstrating potential in data storage and fluorescence cell imaging.
Carrier scattering and relaxation dynamics in n-type In0.83Ga0.17As as a function of temperature and doping density
Authors: Ma Yingjie , Gu Yi , Zhang Yonggang , Chen Xingyou , Xi Suping , Boldizsar Zoltan , Huang Li , Zhou Li
Published: February 2015

The carrier scattering and relaxation dynamics in n-type In0.83Ga0.17As as a function of temperature and doping density were studied.
Benzothiazole-enamide-based BF2 complexes: luminophores exhibiting aggregation-induced emission, tunable emission and highly efficient solid-state emission
Authors: Liu Qingsong , Wang Xiaoqing , Yan Hui , Wu Yanping , Li Zhenyu , Gong Shuwen , Liu Peng , Liu Zhipeng
Published: February 2015

A series of benzothiazole-enamide-based boron difluoride complexes were synthesized and their AIE behaviors, high efficient solid-state emission were investigated.
Programming the quorum sensing-based AND gate in Shewanella oneidensis for logic gated-microbial fuel cells
Authors: Hu Yidan , Yang Yun , Katz Evgeny , Song Hao
Published: February 2015

A modularly structured, flexible, and reprogrammable AND logic gate gene circuit-controlled microbial fuel cell.
Reaction between a haemoglobin model compound and hydrosulphide in aqueous solution
Authors: Watanabe Kenji , Suzuki Toshikane , Kitagishi Hiroaki , Kano Koji
Published: February 2015

The reaction between hydrosulphide and a haemoglobin model compound, composed of a Fe(iii)-porphyrin and a cyclodextrin dimer possessing a pyridine-linker, was studied.
A new chiral C1-symmetric NHC-catalyzed addition to α-aryl substituted α,β-disubstituted enals: enantioselective synthesis of fully functionalized dihydropyranones
Authors: Lu Hong , Liu Jin-Yu , Li Chen-Guang , Lin Jun-Bing , Liang Yong-Min , Xu Peng-Fei
Published: February 2015

A new C1-symmetric biarylsaturated imidazolium exhibits a superior ability to enable previously unavailable transformation, and the corresponding fully functionalized dihydropyranones are efficiently synthesized.
Photocatalytic benzylic C–H bond oxidation with a flavin scandium complex
Authors: Mühldorf Bernd , Wolf Robert
Published: February 2015

Riboflavin tetraacetate–scandium triflate (RFTH+–2Sc3+) is an efficient photocatalyst for the aerobic oxidation of alkylbenzenes and benzyl alcohols to the corresponding aldehydes or ketones.
Manipulation of ionic liquid anion–solute–antisolvent interactions for the purification of acetaminophen
Authors: Weber C. C. , Kunov-Kruse A. J. , Rogers R. D. , Myerson A. S.
Published: February 2015

Strong hydrogen bonding interactions between ionic liquid anions and organic cosolvents led to dramatically reduced acetaminophen solubility which was exploited for its crystallization.
Borylstannylation of alkynes with inverse regioselectivity: copper-catalyzed three-component coupling using a masked diboron
Authors: Yoshida H. , Takemoto Y. , Takaki K.
Published: February 2015

Masked boryl and stannyl moieties are smoothly installed into a carbon–carbon triple bond of diverse terminal alkynes under copper catalysis to provide cis-boryl(stannyl)alkenes in a straightforward manner. The regioselectivity is totally inverted to those of the previous borylstannylations, where a masked boryl moiety is attached to an internal carbon of alkynes.
Very fast catalytic reduction of 4-nitrophenol, methylene blue and eosin Y in natural waters using green chemistry: p(tannic acid)–Cu ionic liquid composites
Authors: Sahiner Nurettin , Sagbas Selin , Aktas Nahit
Published: February 2015

Using tannic acid (TA) as a biopolymer, poly(tannic Acid) (p(TA)) microgels were obtained by cross-linking TA with trimethylolpropane triglycidyl ether (TMPGDE) as cross-linker in a water-in-oil micro emulsion system.
Facile synthesis of a Ag(i)-doped coordination polymer with enhanced catalytic performance in the photodegradation of azo dyes in water
Authors: Wang Fan , Li Fu-Ling , Xu Miao-Miao , Yu Hong , Zhang Jian-Guo , Xia Hai-Tao , Lang Jian-Ping
Published: February 2015

Immersing {[Pb(Tab)2(bpe)]2(PF6)4}n into AgNO3 solution produced a Ag(i)-doped coordination polymer {[Pb(Tab)2(bpe)]2(PF6)4·1.64AgNO3}n, which enhanced the catalytic activity towards azo dye photodegradation.
Identifying potential protein targets for toluene using a molecular similarity search, in silico docking and in vitro validation
Authors: Chushak Y. G. , Chapleau R. R. , Frey J. S. , Mauzy C. A. , Gearhart J. M.
Published: February 2015

The toxicity of chemicals greatly depends on their interaction with macromolecular targets.
Cooperative diversity scheme using SPC in MIMO‐OFDMA system
Authors: Ha Dong‐Hyun , Song Hyoung‐Kyu
Published: February 2015

A method to obtain high diversity gain is proposed by spatial phase coding (SPC) in the cooperative multiple input multiple output‐orthogonal frequency division multiple access (MIMO‐OFDMA) system. SPC provides improved diversity gain dramatically in proportion to the number of received paths although the one‐bit feedback information is used. Moreover, the cooperative MIMO‐OFDMA system has received paths without additional antennas more than the conventional MIMO‐OFDMA system. Therefore, SPC can improve reliability in the cooperative MIMO‐OFDMA system effectively.
Signalling method for mobile communications network
Authors: Heik Badoui Y. , Tafazolli Rahim
Published: February 2015

In this study, a novel and generic signalling method is proposed that results in a significant reduction in signalling messages exchanged between a user equipment and the network over the air interface. Reduction of signalling messages in future mobile cellular systems is an important issue because of the current trend of deploying smaller cells while achieving higher than expected data area capacities. To demonstrate the effectiveness of this method within the standard constraints, some signalling procedures of the 3rd generation mobile standard, Universal Mobile Telecommunication System (UMTS), are investigated. In one application, the number of UMTS packet switch call setup messages was reduced down to three messages only. In such a scenario, measurements show that the gains in comparison with prior call setup is 61% in the duration of the call setup, 50% in the downlink processing delays, 93% in the downlink radio power transmission and 79% in the uplink radio power transmission.
Current problems in magnetic resonance and its applications: Anatole Abragam, Evgenii Zavoiskii, Kazan
Authors: Zhikharev V. A. , Tagirov M. S.
Published: January 2015

In 2014 the world physics community has noted two landmark dates: the seventieth anniversary of the discovery of electron paramagnetic resonance by Evgenii Konstantinovich Zavoiskii (Kazan, 1944) and the centenary of the birth of one of the most brilliant researchers in the area of magnetic microwave spectroscopy, Anatole Izrailevich Abragam. The work of these extraordinary scientists was undoubtedly of Nobel caliber and their influence on the development of the science of magnetic resonances, one of the outstanding discoveries of twentieth century physics, is difficult to overestimate.
Magnetic hyperfine interactions at the 51V nucleus in the pyrochlore Lu2V2O7
Authors: Agzamova P. A. , Petrov V. P. , Chernyshev V. A. , Nikiforov A. E.
Published: January 2015

This is an ab initio calculation of the parameters of the magnetic hyperfine interactions at the 51V nucleus, in the Lu2V2O7 pyrochlore, in addition to a comparative analysis of the calculated values versus known experimental data. It is shown that the unrestricted Hartree-Fock method is more suitable when it comes to describing the magnetic properties at ion nuclei, in comparison to the density functional theory with hybrid functionals B3LYP and PBE0.
E. K. Zavoiskii and NMR: Analysis of laboratory notebooks and rerun of experiments
Authors: Silkin I. I. , Vagapova F. R. , Dooglav A. V.
Published: January 2015

An analysis of the laboratory notebooks of E. K. Zavoiskii, the discoverer of electron paramagnetic resonance, shows that in 1941 he began trying to observe NMR of various nuclei in condensed matter. A rerun of his NMR experiments shows that the sensitivity of the "grid current" method that he developed was adequate for reliable detection of NMR of protons in water solutions of paramagnetic salts. The reason for the poor reproducibility of Zavoiskii's NMR experiments was insufficient the homogeneity of the magnetic field of the electromagnets he used.
Spin-spin relaxation in magnetically dilute crystals
Authors: Dzheparov F. S. , Lvov D. V. , Veretennikov M. A.
Published: January 2015

Magnetic resonance is examined in paramagnetic systems with a small concentration of spins. The free induction signal (FIS) and resonance line shape function (LSF) are calculated. The theory is based on the introduction of an auxiliary system where one spin does not have a flip-flop interaction with the surroundings. The FIS is calculated for this spin using the Anderson-Weiss-Kubo theory and its memory function is used to construct the memory of the main system. The needed numerical coefficients are obtained from expansions of the FIS in terms of the concentration. Here the polarization transport in magnetically dilute systems is taken into account for the first time. This is shown to lead to significant slowing down of the decay in the FIS for times longer than the phase relaxation time. Existing experimental data are compared with theoretical models. Satisfactory agreement is obtained for the description of the central part of the LSF after an additional experimentally observed broadening is introduced in the theory. Data on the amplitude and position of the sideband peaks from the different experiments are not in good agreement with one another or with the theory.
EPR Spectroscopy of catalytic systems based on nickel complexes of 1,4-diaza-1,3-butadiene (α-diimine) ligands in hydrogenation and polymerization reactions
Authors: Titova Yu. Yu. , Belykh L. B. , Schmidt F. K.
Published: January 2015

EPR spectroscopy is used to study catalytic hydration and polymerization reaction systems based on α-diimine complexes of Ni(0) and Ni(II) with the general formula NiBr2(DAD–R) (R = –C3H7 or –CH3) or Ni(DAD–CH3)2 (DAD(–C3H7) = 1,4-bis(2,6-diiso-propylphenyl)-2,3-(dimethyl-1,4-diazabuta-1,3-diene, DAD(–CH3) = 1,4-bis(2,6-dimethylphenyl)-2,3-dimethyl-1,4-diazabuta-1,3-diene)), in combination with Lewis acids (AlEt3, AlEt2Cl, AlEtCl2, B(F5C6)3, BF3·OEt2). Ni(I) complexes of the form (DAD–R)NiX2AlX′y(C2H5)3–y composition (an aluminum atom can be replaced by a boron atom) were identified, where R = –CH3 or –C3H7, X = Br, and X′ = Cl or –C2H5 and α-diimine anion radicals are included in derivatives of aluminum or boron. Oxidation reactions of the Ni(DAD–CH3)2 complex with aluminum alkyl halides and boron derivatives with formation of paramagnetic nickel complexes are observed. It is found that there is no direct relationship between the polymerization activity of ethylene or hydration of the alkenes and the concentration of paramagnetic particles.
The influence of restricted geometry of diamagnetic nanoporous media on 3He relaxation
Authors: Alakshin E. M. , Gazizulin R. R. , Zakharov M. Yu. , Klochkov A. V. , Morozov E. V. , Salikhov T. M. , Safin T. R. , Safiullin K. R. , Tagirov M. S. , Shabanova O. B.
Published: January 2015

This is an experimental study of the spin kinetics of 3He in contact with diamagnetic samples of inverse opals SiO2, and LaF3 nanopowder. It is demonstrated that the nuclear magnetic relaxation of the absorbed 3He occurs due to the modulation of dipole-dipole interaction by the quantum motion in the two-dimensional film. It is found that the relaxation of liquid 3He occurs through a spin diffusion to the absorption layer, and that the restricted geometry of diamagnetic nanoporous media has an influence on the 3He relaxation.
Magnetic resonance of 3He nuclei in porous media
Authors: Klochkov A. V. , Tagirov M. S.
Published: January 2015

A summary of spin kinetics data of 3He in porous media, at temperatures above the Fermi degeneracy of this quantum liquid. The presented results were obtained at Kazan Federal University during the past ten years, and are the foundation for developing the method of helium porosimetry. We propose methodological guidelines for investigating samples with unknown pore sizes and surface properties.
Crystal field simulation and NMR study of 19F in a EuF3 Van Vleck paramagnet
Authors: Savinkov A. V. , Dooglav A. V. , Malkin B. Z. , Tagirov M. S. , Korableva S. L.
Published: January 2015

The temperature dependence of the nuclear spin-lattice relaxation rate of 19F nuclei is measured for a powder sample of a EuF3 Van Vleck paramagnet, in a broad temperature range (55–300 K). The increase in the nuclear relaxation rate observed at T > 100 K is caused by fluctuations in the magnetic fields, induced at the fluorine nuclei by the magnetic moments of the europium ions, the lifetime of which is determined by a two-phonon relaxation process with input from the first excited state of the electron shell of Eu3+ ions (Δ1 = 370 K). The set of crystal field parameters allowing for a satisfactory description of the electron energy spectrum of the Eu3+ ions in the EuF3 crystal, is calculated within the framework of the semi-phenomenological exchange charge model.
Magnetic resonance and spin-reorientation transitions in the Nd0.75Ho0.25Fe3(BO3)4 multiferroic
Authors: Kobets M. I. , Dergachev K. G. , Gnatchenko S. L. , Khatsko E. N. , Bezmaternykh L. N. , Gudim I. A.
Published: January 2015

A presentation of experimental study results obtained by antiferromagnetic resonance (AFMR) of the high-frequency properties of the multiferroic Nd0.75Ho0.25Fe3(BO3)4 in a broad range of temperatures and frequencies. We studied the effect of substituting the Nd3+ ions with Ho3+, on the resonance properties of the Nd0.75Ho0.25Fe3(BO3)4 solid solution. In addition, we investigated the particularities of magnetic-field induced spin-reorientation phase transitions for H||c and H||a directions, in which the anisotropy of the magnetic system is measured from “easy-axis” anisotropy to “easy-plane.” The AFMR modes of a Fe3+ subsystem are revealed. New information about the most important characteristics of AFM is obtained, including: frequency-field dependence of the AFMR spectrum, gaps in the spin-wave spectrum, effective magnetic anisotropy values, and fields of spin-reorientation transitions. It is shown that “easy-plane” anisotropy prevails in this magnet, with a weak anisotropy in the basal plane. For the first time there are observed features in the AFMR spectra that could be tied to the presence of a spatially modulated spin structure (incommensurate phase) in AFM Nd0.75Ho0.25Fe3(BO3)4.
A split-beam probe-pump-probe scheme for femtosecond time resolved protein X-ray crystallography
Authors: van Thor Jasper J. , Madsen Anders
Published: January 2015

In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/σI) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or “probe-pump-probe”) which will allow experimental determination of the photo-induced structure factor amplitude differences, ΔF, in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse.
The wet solidus of silica: Predictions from the scaled particle theory and polarized continuum model
Authors: Ottonello G. , Richet P. , Vetuschi Zuccolini M.
Published: February 2015

We present an application of the Scaling Particle Theory (SPT) coupled with an ab initio assessment of the electronic, dispersive, and repulsive energy terms based on the Polarized Continuum Model (PCM) aimed at reproducing the observed solubility behavior of OH2 over the entire compositional range from pure molten silica to pure water and wide pressure and temperature regimes. It is shown that the solution energy is dominated by cavitation terms, mainly entropic in nature, which cause a large negative solution entropy and a consequent marked increase of gas phase fugacity with increasing temperatures. Besides, the solution enthalpy is negative and dominated by electrostatic terms which depict a pseudopotential well whose minimum occurs at a low water fraction (XH2O) of about 6 mol. %. The fine tuning of the solute-solvent interaction is achieved through very limited adjustments of the electrostatic scaling factor γel which, in pure water, is slightly higher than the nominal value (i.e., γel  =  1.224 against 1.2), it attains its minimum at low H2O content (γel = 0.9958) and then rises again at infinite dilution (γel   =  1.0945). The complex solution behavior is interpreted as due to the formation of energetically efficient hydrogen bonding when OH functionals are in appropriate amount and relative positioning with respect to the discrete OH2 molecules, reinforcing in this way the nominal solute-solvent inductive interaction. The interaction energy derived from the SPT-PCM calculations is then recast in terms of a sub-regular Redlich-Kister expansion of appropriate order whereas the thermodynamic properties of the H2O component at its standard state (1-molal solution referred to infinite dilution) are calculated from partial differentiation of the solution energy over the intensive variables.
On exponential stability of linear Levin-Nohel integro-differential equations
Authors: Tien Dung Nguyen
Published: February 2015

The aim of this paper is to investigate the exponential stability for linear Levin-Nohel integro-differential equations with time-varying delays. To the best of our knowledge, the exponential stability for such equations has not yet been discussed. In addition, since we do not require that the kernel and delay are continuous, our results improve those obtained in Becker and Burton [Proc. R. Soc. Edinburgh, Sect. A: Math. 136, 245-275 (2006)]; Dung [J. Math. Phys. 54, 082705 (2013)]; and Jin and Luo [Comput. Math. Appl. 57(7), 1080-1088 (2009)].
Relativistic corrections to the Moyal-Weyl spacetime
Authors: Much A.
Published: February 2015

We use the framework of quantum field theory to obtain by deformation the Moyal-Weyl spacetime. This idea is extracted from recent progress in deformation theory concerning the emergence of the quantum plane of the Landau-quantization. The quantum field theoretical emerging spacetime is not equal to the standard Moyal-Weyl plane, but terms resembling relativistic corrections occur.
Electrodynamics of massless charged particles
Authors: Lechner Kurt
Published: February 2015

We derive the classical dynamics of massless charged particles in a rigorous way from first principles. Since due to ultraviolet divergences this dynamics does not follow from an action principle, we rely on (a) Maxwell’s equations, (b) Lorentz- and reparameterization-invariance, and (c) local conservation of energy and momentum. Despite the presence of pronounced singularities of the electromagnetic field along Dirac-like strings, we give a constructive proof of the existence of a unique distribution-valued energy-momentum tensor. Its conservation requires the particles to obey standard Lorentz equations and they experience, hence, no radiation reaction. Correspondingly, the dynamics of interacting classical massless charged particles can be consistently defined, although they do not emit bremsstrahlung end experience no self-interaction.
Selective growth of single phase VO2(A, B, and M) polymorph thin films
Authors: Srivastava Amar , Rotella Helene , Saha Surajit , Pal Banabir , Kalon Gopinadhan , Mathew Sinu , Motapothula Mallikarjuna , Dykas Michal , Yang Ping , Okunishi Eiji , Sarma D. D. , Venkatesan T.
Published: February 2015

We demonstrate the growth of high quality single phase films of VO2(A, B, and M) on SrTiO3 substrate by controlling the vanadium arrival rate (laser frequency) and oxidation of the V atoms. A phase diagram has been developed (oxygen pressure versus laser frequency) for various phases of VO2 and their electronic properties are investigated. VO2(A) phase is insulating VO2(B) phase is semi-metallic, and VO2(M) phase exhibits a metal-insulator transition, corroborated by photo-electron spectroscopic studies. The ability to control the growth of various polymorphs opens up the possibility for novel (hetero)structures promising new device functionalities.
Ratcheting fluid with geometric anisotropy
Authors: Thiria Benjamin , Zhang Jun
Published: February 2015

We investigate a mechanism that effectively transports fluids using vibrational motion imposed onto fluid boundary with anisotropy. In our experiment, two asymmetric, sawtooth-like structures are placed facing each other and form a corrugated fluid channel. This channel is then forced to open and close periodically. Under reciprocal motion, fluid fills in the gap during the expansion phase of the channel and is then forced out during contraction. Since the fluid experiences different impedances when flowing in different directions, the stagnation point that separates flows of two directions changes within each driving period. As a result, fluid is transported unidirectionally. This ratcheting effect of fluid is demonstrated through our measurements and its working principle discussed in some detail.
Asymmetric edge modes by staggered potential in honeycomb lattice: Spin splitter
Authors: Chen Son-Hsien , Sun Shih-Jye , Su Yu-Hsin , Chang Ching-Ray
Published: February 2015

In honeycomb lattice with staggered potential such as silicene nanoribbon (SN) as used for illustrations here, we show that the lack of inversion symmetry due to buckled structure can lead to asymmetric edge modes where only one edge is utilized in transport, yielding no cross-walk (due to size effect) between edges. We also find asymmetric Hall accumulations formed because of the presence of staggered potential. Applying two opposite out-of-plane electric fields to two adjacent SNs appropriately, so that cross-walk occurs between two internal edge states, the bulk states serve as a spin-splitter that splits two specious of spins (spin-up and spin-down) into those two SNs. The spin-splitter proposed here does not require any magnetic field and thus manipulates spins in a full electric manner.
Research Update: Comparison of salt- and molecular-based iodine treatments of PbS nanocrystal solids for solar cells
Authors: Jähnig Fabian , Bozyigit Deniz , Yarema Olesya , Wood Vanessa
Published: February 2015

Molecular- and salt-based chemical treatments are believed to passivate electronic trap states in nanocrystal-based semiconductors, which are considered promising for solar cells but suffer from high carrier recombination. Here, we compare the chemical, optical, and electronic properties of PbS nanocrystal-based solids treated with molecular iodine and tetrabutylammonium iodide. Surprisingly, both treatments increase—rather than decrease—the number density of trap states; however, the increase does not directly influence solar cell performance. We explain the origins of the observed impact on solar cell performance and the potential in using different chemical treatments to tune charge carrier dynamics in nanocrystal-solids.
A gyrokinetic one-dimensional scrape-off layer model of an edge-localized mode heat pulse
Authors: Shi E. L. , Hakim A. H. , Hammett G. W.
Published: February 2015

An electrostatic gyrokinetic-based model is applied to simulate parallel plasma transport in the scrape-off layer to a divertor plate. The authors focus on a test problem that has been studied previously, using parameters chosen to model a heat pulse driven by an edge-localized mode in JET. Previous work has used direct particle-in-cell equations with full dynamics, or Vlasov or fluid equations with only parallel dynamics. With the use of the gyrokinetic quasineutrality equation and logical sheath boundary conditions, spatial and temporal resolution requirements are no longer set by the electron Debye length and plasma frequency, respectively. This test problem also helps illustrate some of the physics contained in the Hamiltonian form of the gyrokinetic equations and some of the numerical challenges in developing an edge gyrokinetic code.
Effects of Zn additions to highly magnetoelastic FeGa alloys
Authors: Lograsso Thomas A. , Jones Nicholas J. , Schlagel Deborah L. , Petculescu Gabriela , Wun-Fogle Marilyn , Restorff James B. , Clark Arthur E. , Hathaway Kristl B.
Published: February 2015

Fe1−xMx (M = Ga, Ge, Si, Al, Mo and x ∼ 0.18) alloys offer an extraordinary combination of magnetoelasticity and mechanical properties. They are rare-earth-free, can be processed using conventional deformation techniques, have high magnetic permeability, low hysteresis, and low magnetic saturation fields, making them attractive for device applications such as actuators and energy harvesters. Starting with Fe-Ga as a reference and using a rigid-band-filling argument, Zhang et al. predicted that lowering the Fermi level by reducing the total number of electrons could enhance magnetoelasticity. To provide a direct experimental validation for Zhang's hypothesis, elemental additions with lower-than-Ga valence are needed. Of the possible candidates, only Be and Zn have sufficient solubility. Single crystals of bcc Fe-Ga-Zn have been grown with up to 4.6 at. % Zn in a Bridgman furnace under elevated pressure (15 bars) in order to overcome the high vapor pressure of Zn and obtain homogeneous crystals. Single-crystal measurements of magnetostriction and elastic constants allow for the direct comparison of the magnetoelastic coupling constants of Fe-Ga-Zn with those of other magnetoelastic alloys in its class. The partial substitution of Ga with Zn yields values for the magnetoelastic coupling factor, −b1, comparable to those of the binary Fe-Ga alloy.