bluuebunny/crossref_metadata_2025 huggingface dataset:
Smoking Normalizes Cerebral Blood Flow and Oxygen Consumption after 12-Hour Abstention
Authors: Vafaee Manouchehr S , Gjedde Albert , Imamirad Nasrin , Vang Kim , Chakravarty Mallar M , Lerch Jason P , Cumming Paul
Published: January 2015

Acute nicotine administration stimulates [14C]deoxyglucose trapping in thalamus and other regions of rat brain, but acute effects of nicotine and smoking on energy metabolism have rarely been investigated in human brain by positron emission tomography (PET). We obtained quantitative PET measurements of cerebral blood flow (CBF) and metabolic rate of oxygen (CMRO2) in 12 smokers who had refrained from smoking overnight, and in a historical group of nonsmokers, testing the prediction that overnight abstinence results in widespread, coupled reductions of CBF and CMRO2. At the end of the abstention period, global grey-matter CBF and CMRO2 were both reduced by 17% relative to nonsmokers. At 15 minutes after renewed smoking, global CBF had increased insignificantly, while global CMRO2 had increased by 11%. Regional analysis showed that CMRO2 had increased in the left putamen and thalamus, and in right posterior cortical regions at this time. At 60 and 105 minutes after smoking resumption, CBF had increased by 8% and CMRO2 had increased by 11–12%. Thus, we find substantial and global impairment of CBF/CMRO2 in abstaining smokers, and acute restoration by resumption of smoking. The reduced CBF and CMRO2 during acute abstention may mediate the cognitive changes described in chronic smokers.
Assessment of Metabolic Fluxes in the Mouse Brain in Vivo Using 1H-[13C] NMR Spectroscopy at 14.1 Tesla
Authors: Xin Lijing , Lanz Bernard , Lei gxia , Gruetter Rolf
Published: January 2015

13C magnetic resonance spectroscopy (MRS) combined with the administration of 13C labeled substrates uniquely allows to measure metabolic fluxes in vivo in the brain of humans and rats. The extension to mouse models may provide exclusive prospect for the investigation of models of human diseases. In the present study, the short-echo-time (TE) full-sensitivity 1H-[13C] MRS sequence combined with high magnetic field (14.1 T) and infusion of [U-13C6] glucose was used to enhance the experimental sensitivity in vivo in the mouse brain and the 13C turnover curves of glutamate C4, glutamine C4, glutamate+glutamine C3, aspartate C2, lactate C3, alanine C3, γ-aminobutyric acid C2, C3 and C4 were obtained. A one-compartment model was used to fit 13C turnover curves and resulted in values of metabolic fluxes including the tricarboxylic acid (TCA) cycle flux VTCA (1.05 ± 0.04 μmol/g per minute), the exchange flux between 2-oxoglutarate and glutamate Vx (0.48 ± 0.02 μmol/g per minute), the glutamate-glutamine exchange rate Vgln (0.20 ± 0.02 μmol/g per minute), the pyruvate dilution factor Kdil (0.82 ± 0.01), and the ratio for the lactate conversion rate and the alanine conversion rate VLac/ VAla (10 ± 2). This study opens the prospect of studying transgenic mouse models of brain pathologies.
In Vivo and Ex Vivo Magnetic Resonance Spectroscopy of the Infarct and the Subventricular Zone in Experimental Stroke
Authors: Jiménez-Xarrié Elena , Davila Myriam , Gil-Perotín Sara , Jurado-Rodríguez Andrés , Candiota Ana Paula , Delgado-Mederos Raquel , Lope-Piedrafita Silvia , García-Verdugo José Manuel , Arús Carles , Martí-Fàbregas Joan
Published: January 2015

Ex vivo high-resolution magic-angle spinning (HRMAS) provides metabolic information with higher sensitivity and spectral resolution than in vivo magnetic resonance spectroscopy (MRS). Therefore, we used both techniques to better characterize the metabolic pattern of the infarct and the neural progenitor cells (NPCs) in the ipsilateral subventricular zone (SVZi). Ischemic stroke rats were divided into three groups: G0 (non-stroke controls, n = 6), G1 (day 1 after stroke, n = 6), and G7 (days 6 to 8 after stroke, n =12). All the rats underwent MRS. Three rats per group were analyzed by HRMAS. The remaining rats were used for immunohistochemical studies. In the infarct, both techniques detected significant metabolic changes. The most relevant change was in mobile lipids (2.80 ppm) in the G7 group (a 5.53- and a 3.95-fold increase by MRS and HRMAS, respectively). In the SVZi, MRS did not detect any significant metabolic change. However, HRMAS detected a 2.70-fold increase in lactate and a 0.68-fold decrease in N-acetylaspartate in the G1 group. None of the metabolites correlated with the 1.37-fold increase in NPCs detected by immunohistochemistry in the G7 group. In conclusion, HRMAS improves the metabolic characterization of the brain in experimental ischemic stroke. However, none of the metabolites qualifies as a surrogate biomarker of NPCs.
The Spectrum of MR Detectable Cortical Microinfarcts: A Classification Study with 7-Tesla Postmortem MRI and Histopathology
Authors: van Veluw Susanne J , Zwanenburg Jaco JM , Rozemuller Annemieke JM , Luijten Peter R , Spliet Wim GM , Biessels Geert Jan
Published: January 2015

Cerebral microinfarcts (CMIs) are common neuropathologic findings in aging and dementia. We explored the spectrum of cortical CMIs that can be visualized with 7T magnetic resonance imaging (MRI). Thirty-three coronal brain slices of 11 individuals with neuropathologically confirmed dementia were subjected to a high-resolution postmortem 7T MRI protocol. First, we identified all visible small (5 mm) intracortical and juxtacortical lesions on postmortem MRI. Lesions were classified as CMI or nonCMI based on histology, and their MR features were recorded. Thirty lesions were identified on the initial MRI evaluation, of which twenty-three could be matched with histology. Histopathology classified 12 lesions as CMIs, all of which were located intracortically. On the basis of their MR features, they could be classified as chronic gliotic CMIs—with or without cavitation or hemorrhagic components—and acute CMIs. Eleven MRI identified lesions were not of ischemic nature and most commonly enlarged or atypically shaped perivascular spaces. Their MRI features were similar to gliotic CMIs with or without cavitation, but these ‘CMI mimics’ were always located juxtacortically. 7T postmortem MRI distinguishes different histopathologic types of cortical CMIs, with distinctive MR characteristics. On the basis of our findings, we propose in vivo rating criteria for the detection of intracortical CMIs.
Regulation of T-cell activation and migration by the kinase TBK1 during neuroinflammation
Authors: Yu Jiayi , Zhou Xiaofei , Chang Mikyoung , Nakaya Mako , Chang Jae-Hoon , Xiao Yichuan , William Lindsey J. , Dorta-Estremera Stephanie , Cao Wei , Zal Anna , Zal Tomasz , Sun Shao-Cong
Published: January 2015

Development of an immune or autoimmune response involves T-cell activation in lymphoid organs and subsequent migration to peripheral tissues. Here we show that T-cell-specific ablation of the kinase TBK1 promotes T-cell activation but causes retention of effector T cells in the draining lymph node in a neuroinflammatory autoimmunity model, experimental autoimmune encephalomyelitis (EAE). At older ages, the T-cell-conditional TBK1-knockout mice also spontaneously accumulate T cells with activated phenotype. TBK1 controls the activation of AKT and its downstream kinase mTORC1 by a mechanism involving TBK1-stimulated AKT ubiquitination and degradation. The deregulated AKT-mTORC1 signalling in turn contributes to enhanced T-cell activation and impaired effector T-cell egress from draining lymph nodes. Treatment of mice with a small-molecule inhibitor of TBK1 inhibits EAE induction. These results suggest a role for TBK1 in regulating T-cell migration and establish TBK1 as a regulator of the AKT-mTORC1 signalling axis.
The adhesion G protein-coupled receptor GPR56 is a cell-autonomous regulator of oligodendrocyte development
Authors: Giera Stefanie , Deng Yiyu , Luo Rong , Ackerman Sarah D. , Mogha Amit , Monk Kelly R. , Ying Yanqin , Jeong Sung-Jin , Makinodan Manabu , Bialas Allison R. , Chang Bernard S. , Stevens Beth , Corfas Gabriel , Piao Xianhua
Published: January 2015

Mutations inGPR56, a member of the adhesion G protein-coupled receptor family, cause a human brain malformation called bilateral frontoparietal polymicrogyria (BFPP). Magnetic resonance imaging (MRI) of BFPP brains reveals myelination defects in addition to brain malformation. However, the cellular role of GPR56 in oligodendrocyte development remains unknown. Here, we demonstrate that loss ofGpr56leads to hypomyelination of the central nervous system in mice. GPR56 levels are abundant throughout early stages of oligodendrocyte development, but are downregulated in myelinating oligodendrocytes.Gpr56-knockout mice manifest with decreased oligodendrocyte precursor cell (OPC) proliferation and diminished levels of active RhoA, leading to fewer mature oligodendrocytes and a reduced number of myelinated axons in the corpus callosum and optic nerves. Conditional ablation ofGpr56in OPCs leads to a reduced number of mature oligodendrocytes as seen in constitutive knockout ofGpr56. Together, our data define GPR56 as a cell-autonomous regulator of oligodendrocyte development.
Group size effect on cooperation in one-shot social dilemmas
Authors: Barcelo Hélène , Capraro Valerio
Published: January 2015

Social dilemmas are central to human society. Depletion of natural resources, climate protection, security of energy supply and workplace collaborations are all examples of social dilemmas. Since cooperative behaviour in a social dilemma is individually costly, Nash equilibrium predicts that humans should not cooperate. Yet experimental studies show that people do cooperate even in anonymous one-shot interactions. In spite of the large number of participants in many modern social dilemmas, little is known about the effect of group size on cooperation. Does larger group size favour or prevent cooperation? We address this problem both experimentally and theoretically. Experimentally, we find that there is no general answer: it depends on the strategic situation. Specifically, we find that larger groups are more cooperative in the Public Goods game, but less cooperative in the N-person Prisoner's dilemma. Theoretically, we show that this behaviour is not consistent with either the Fehr & Schmidt model or (a one-parameter version of) the Charness & Rabin model, but it is consistent with the cooperative equilibrium model introduced by the second author.
Electrical conductivity, isothermal stability and amine sensing studies of a synthetic poly-o-toluidine/multiwalled carbon nanotube/Sn(iv) tungstate composite ion exchanger doped with p-toluene sulfonic acid
Authors: Khan Asif Ali , Shaheen Shakeeba
Published: January 2015

An electrically conductive poly-o-toluidine (POT) composite doped with p-toluene sulfonic acid (pTSA) was prepared using multiwalled carbon nanotubes (MWCNTs) and Sn(iv) tungstate (ST) by in situ oxidative polymerization.
A novel hanging spherical drop system for the generation of cellular spheroids and high throughput combinatorial drug screening
Authors: Neto A. I. , Correia C. R. , Oliveira M. B. , Rial-Hermida M. I. , Alvarez-Lorenzo C. , Reis R. L. , Mano J. F.
Published: January 2015

A novel hanging spherical drop system based on the use of biomimetic superhydrophobic flat substrates allows one to generate arrays of independent spheroid bodies in a high throughput manner, in order to mimicin vivotumour models on the lab-on-chip scale.
Selective fluorogenic imaging of hepatocellular H2S by a galactosyl azidonaphthalimide probe
Authors: Shi De-Tai , Zhou Dan , Zang Yi , Li Jia , Chen Guo-Rong , James Tony D. , He Xiao-Peng , Tian He
Published: January 2015

A galatosyl azidonaphthalimide probe is developed for the selective, fluorogenic imaging of hepatocellular H2S.
A dual colorimetric-ratiometric fluorescent probe NAP-3 for selective detection and imaging of endogenous labile iron(iii) pools in C. elegans
Authors: Goel Atul , Umar Shahida , Nag Pankaj , Sharma Ashutosh , Kumar Lalit , Shamsuzzama Shamsuzzama , Hossain Zakir , Gayen Jiaur R. , Nazir Aamir
Published: January 2015

The first dual colorimetric and ratiometric fluorescent probe NAP-3 for selective visualization of labile iron(iii) pools in Caenorhabditis elegans is reported.
Kinetic and thermodynamic processes of organic species at the solution–solid interface: the view through an STM
Authors: Mazur Ursula , Hipps K. W.
Published: January 2015

STM based kinetic and thermodynamic studies of ordered organic adlayer formation at the solution–solid interface.
Ultra-small nanoparticles of MgTi2O5 embedded in carbon rods with superior rate performance for sodium ion batteries
Authors: Xie Fangxi , Deng Yuanfu , Xie Ye , Xu Hongjie , Chen Guohua
Published: January 2015

Confinement of ultra-small MgTi2O5 nanoparticles in carbon is demonstrated as to be an efficient method for fabricating long cycle-life anode material for sodium ion batteries.
Influence of oleic acid on the nucleation and growth of 4-N,N-dimethylamino-4-N-methyl-stilbazoliumtosylate (DAST) crystals
Authors: Thomas Tina , Ramaclus Jerald V. , Mena Fausto P. , Mosquera Edgar , Sagayaraj P. , Michael Ernest A.
Published: January 2015

A simple solvent evaporation method, to control the nucleation and morphology of DAST single crystals is explored using a fatty acid as an additive.
Investigating the role of human serum albumin protein pocket on the excited state dynamics of indocyanine green using shaped femtosecond laser pulses
Authors: Nairat Muath , Konar Arkaprabha , Kaniecki Marie , Lozovoy Vadim V. , Dantus Marcos
Published: January 2015

When indocyanine green (ICG) is confined inside the pocket of human serum albumin its triplet state formation is mitigated and coherent vibrational motion becomes more observable.
Hydrogen bonding in a mixture of protic ionic liquids: a molecular dynamics simulation study
Authors: Paschek Dietmar , Golub Benjamin , Ludwig Ralf
Published: January 2015

We report results of molecular dynamics (MD) simulations characterising the hydrogen bonding in mixtures of two different protic ionic liquids sharing the same cation: triethylammonium-methylsulfonate (TEAMS) and triethylammonium-triflate (TEATF).
Lanthanide single molecule magnets: progress and perspective
Authors: Zhang Peng , Zhang Li , Tang Jinkui
Published: January 2015

The recent developments in lanthanide SMMs highlighted in this frontier article indicate the directions to which further synthetic efforts should be focused.
Tetraguanidino-functionalized phenazine and fluorene dyes: synthesis, optical properties and metal coordination
Authors: Bindewald Elvira , Lorenz Roxana , Hübner Olaf , Brox Dominik , Herten Dirk-Peter , Kaifer Elisabeth , Himmel Hans-Jörg
Published: January 2015

Functionalization of phenazine with guanidino groups leads to new highly fluorescent dyes and ligands, and metal coordination is shown to alter significantly the optical properties.
Pluronic copolymer encapsulated SCR7 as a potential anticancer agent
Authors: John Franklin , George Jinu , Srivastava Mrinal , Hassan P. A. , Aswal V. K. , Karki Subhas. S. , Raghavan Sathees. C.
Published: January 2015

Nonhomologous end joining (NHEJ) of DNA double strand breaks (DSBs) inside cells can be selectively inhibited by 5,6-bis-(benzylideneamino)-2-mercaptopyrimidin-4-ol (SCR7) which possesses anticancer properties. The hydrophobicity of SCR7 decreases its bioavailability which is a major setback in the utilization of this compound as a therapeutic agent. In order to circumvent the drawback of SCR7, we prepared a polymer encapsulated form of SCR7. The physical interaction of SCR7 and Pluronic® copolymer is evident from different analytical techniques. The in vitro cytotoxicity of the drug formulations is established using the MTT assay.
The study on the material basis and the mechanism for anti-renal interstitial fibrosis efficacy of rhubarb through integration of metabonomics and network pharmacology
Authors: Xiang Zheng , Sun Hao , Cai Xiaojun , Chen Dahui , Zheng Xiaoyong
Published: January 2015

The cooperative material basis of the multi-component and multi-target mechanism of action of Traditional Chinese Medicine (TCM) is difficult to elucidate because of the current lack of appropriate techniques and strategies.
An integrated analysis of differential miRNA and mRNA expressions in human gallstones
Authors: Yang Bin , Liu Bin , Bi Pinduan , Wu Tao , Wang Qiang , Zhang Jie
Published: January 2015

An integrated analysis of differential miRNA and mRNA expressions firstly revealed that miR-210 and its target ATP11A may involve in the ABC-transporters pathway, which contribute to gallstone formation.
Green catalyst: magnetic La0.7Sr0.3MnO3 hollow microspheres
Authors: Zhou Cuiping , Huang Keke , Yuan Long , Feng Wenchun , Chu Xuefeng , Geng Zhibin , Wu Xiaofeng , Wang Liying , Feng Shouhua
Published: January 2015

Compared with nanoparticles, the rugged microspherical structure makes the magnetic La0.7Sr0.3MnO3 more favorable for photocatalytic water oxidation.
Improved light absorption and photocatalytic activity of Zn,N-TiO2−x rich in oxygen vacancies synthesized by nitridation and hydrogenation
Authors: Hu Yidong , Chen Gang , Li Chunmei , Yu Yaoguang , Sun Jingxue , Dong Hongjun
Published: January 2015

Compared with N-TiO2 and Zn,N-TiO2 samples, Zn,N-TiO2−x rich in oxygen vacancies demonstrates high photocatalytic activity.
Synthetic and immunological studies of N-acyl modified S-linked STn derivatives as anticancer vaccine candidates
Authors: Huo Chang-Xin , Zheng Xiu-Jing , Xiao An , Liu Chang-Cheng , Sun Shuang , Lv Zhuo , Ye Xin-Shan
Published: January 2015

N-ModifiedS-linked STn glycoconjugates significantly stimulated the production of IgG antibodies capable of recognizing the naturally occurring STn antigen.
A mechanistic proposal for the protodeboronation of neat boronic acids: boronic acid mediated reaction in the solid state
Authors: Noonan Gary , Leach Andrew G.
Published: January 2015

Boronic acids that undergo protodeboronation as solids are stable in solution: the solid state organizes them for reaction.
EGFR/HER-2 inhibitors: synthesis, biological evaluation and 3D-QSAR analysis of dihydropyridine-containing thiazolinone derivatives
Authors: Ren Yu-Jia , Wang Zhong-Chang , Zhang Xin , Qiu Han-Yue , Wang Peng-Fei , Gong Hai-Bin , Jiang Ai-Qin , Zhu Hai-Liang
Published: January 2015

A series of dihydropyridin containing thiazolinone derivatives (4a–4r) have been designed, synthesized and their biological activities were also evaluated as potential EGFR and HER-2 kinase inhibitors and tumor cell antiproliferation.
An Au–Cu bimetal catalyst for acetylene hydrochlorination with renewable γ-Al2O3 as the support
Authors: Zhao Jigang , Zeng Junjian , Cheng Xiaoguang , Wang Lei , Yang Henghua , Shen Benxian
Published: January 2015

The bimetal catalyst gold(iii) chloride–copper(ii) chloride (AuCl3–CuCl2) was prepared with different gamma-aluminium oxide (γ-Al2O3) supports and its catalytic properties towards acetylene hydrochlorination were assessed in a fixed-bed reactor.
Anisotropic vacancy-defect-induced fracture strength loss of graphene
Authors: Sun Xiao-Yu , Hu Heng , Cao Changyong , Xu Yuan-Jie
Published: January 2015

The fracture strength of defective graphene at the orientation angle of 15° has the smallest sensitivity to vacancy defects.
Metabolic transformation evidence of caffeic acid derivatives in male rats after the oral administration of functional food by UPLC coupled with a hybrid quadrupole-orbitrap mass spectrometer
Authors: Cao Shuyuan , Zhang Zhan , Ye Yuting , Chen Lijun , Li Yuan , Yu Xinyu , Yang Ye , Wang Li , Li Zhong , Li Lei
Published: January 2015

This study revealed the possible metabolic pathway of DSC by an analysis of the CADs and their metabolites in rat plasma using Q Exactive UPLC-MS/MS.
Extraction process of sulfur compounds from fuels with protic ionic liquids
Authors: Li Zhuo , Xu Jinggang , Li Dan , Li Changping
Published: January 2015

Sulfur compounds in fuels are hazardous to the environment and present a great challenge. In this study, a series of protic ionic liquids (PILs) was designed and their extraction desulfurization capability was evaluated.
Suppressing singlet oxygen formation from 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin using polyion complex micelles
Authors: Zheng Ruyi , Wu Zheng , Yan Yun , Wang Jide , Huang Jianbin
Published: January 2015

The production of 1O2 from TPPS can be reduced by the formation of polyion micelles with PMVP41-b-PEO205.
The enhanced field emission properties of K and Rb doped (5,5) capped single-walled carbon nanotubes
Authors: Wang Yue , Yao Xin-Hua , Huang Gang , Shao Qing-Yi
Published: January 2015

The field emission properties of alkali metal K and Rb (AM) doped (5,5) capped single-walled carbon nanotubes (CNTs) have been investigated using first-principles theory.
Prediction of structural and thermomechanical properties of polymers from multiscale simulations
Authors: Maurel Gaëtan , Goujon Florent , Schnell Benoit , Malfreyt Patrice
Published: January 2015

We report mesoscale simulations of polymer melts and crosslinked polymer networks by using realistic coarse-grained (CG) models that are developed from atomistic simulations of polymer melts.
Photostick: a method for selective isolation of target cells from culture
Authors: Chien Miao-Ping , Werley Christopher A. , Farhi Samouil L. , Cohen Adam E.
Published: January 2015

A new method enables optical selection of one or more cells in culture via photochemical crosslinking to the culture dish.
Interfacial chemical oxidative synthesis of multifunctional polyfluoranthene
Authors: Li Xin-Gui , Liao Yaozu , Huang Mei-Rong , Kaner Richard B.
Published: January 2015

Polyfluoranthene, synthesized by an interfacial cationic oxidative polymerization of fluoranthene, emits visible fluorescence that shows highly selective sensitivity to Fe3+.
Extreme red shifted SERS nanotags
Authors: Bedics Matthew A. , Kearns Hayleigh , Cox Jordan M. , Mabbott Sam , Ali Fatima , Shand Neil C. , Faulds Karen , Benedict Jason B. , Graham Duncan , Detty Michael R.
Published: January 2015

Extreme red-shifted nanotags have been developed and they provide effective SERS with picomolar detection limits when excited at 1280 nm.
Flaws in foldamers: conformational uniformity and signal decay in achiral helical peptide oligomers
Authors: Le Bailly Bryden A. F. , Byrne Liam , Diemer Vincent , Foroozandeh Mohammadali , Morris Gareth A. , Clayden Jonathan
Published: January 2015

The conformational influence of a single stereogenic centre in an otherwise achiral oligomer behaves as a signal that decays with distance.
Interconvertible multiple photoluminescence color of a gold(i) isocyanide complex in the solid state: solvent-induced blue-shifted and mechano-responsive red-shifted photoluminescence
Authors: Seki Tomohiro , Ozaki Taichi , Okura Takuma , Asakura Kiyotaka , Sakon Aya , Uekusa Hidehiro , Ito Hajime
Published: January 2015

We report the first example of a mechanochromic compound that can switch between four individual types of photoluminescence in the solid state.
New evidence disclosed for networking in natural rubber by dielectric relaxation spectroscopy
Authors: Liu Jie , Wu Siwu , Tang Zhenghai , Lin Tengfei , Guo Baochun , Huang Guangsu
Published: January 2015

A branch relaxation mode was identified for the first time, which provides new implications for natural networking structures in natural rubber.
An electrospun strong PCL/PU composite vascular graft with mechanical anisotropy and cyclic stability
Authors: Guo Fengyun , Wang Nü , Wang Li , Hou Lanlan , Ma Lan , Liu Jing , Chen Yuee , Fan Bingbing , Zhao Yong
Published: January 2015

A high-strength PCL/PU composite vascular graft with excellent cycle stability and cell compatibility was fabricated by electrospinning.
Catalytic oxidation of formaldehyde in water by calcium phosphate-based Pt composites
Authors: Fam Yakub , Imae Toyoko
Published: January 2015

Catalytic degradation of HCHO begins with the dissolution of O2gas from atmosphere into an HCHO solution. O2and HCHO in a solution are then adsorbed onto active sites of PtNPs catalyst, and the complete oxidation happens to generate CO2and H2O.
Going for broke: targeting the human cancer pseudokinome
Authors: Bailey Fiona P. , Byrne Dominic P. , McSkimming Daniel , Kannan Natarajan , Eyers Patrick A.
Published: January 2015

Protein phosphorylation lies at the heart of cell signalling, and somatic mutation(s) in kinases drives and sustains a multitude of human diseases, including cancer. The human protein kinase superfamily (the kinome) encodes approximately 50 ‘pseudokinases’, which were initially predicted to be incapable of dynamic cell signalling when compared with canonical enzymatically active kinases. This assumption was supported by bioinformatics, which showed that amino acid changes at one or more key loci, making up the nucleotide-binding site or phosphotransferase machinery, were conserved in multiple vertebrate and non-vertebrate pseudokinase homologues. Protein kinases are highly attractive targets for drug discovery, as evidenced by the approval of almost 30 kinase inhibitors in oncology, and the successful development of the dual JAK1/2 (Janus kinase 1/2) inhibitor ruxolitinib for inflammatory indications. However, for such a large (>550) protein family, a remarkable number have still not been analysed at the molecular level, and only a surprisingly small percentage of kinases have been successfully targeted clinically. This is despite evidence that many are potential candidates for the development of new therapeutics. Indeed, several recent reports confirm that disease-associated pseudokinases can bind to nucleotide co-factors at concentrations achievable in the cell. Together, these findings suggest that drug targeting using either ATP-site or unbiased ligand-discovery approaches should now be attempted using the validation technology currently employed to evaluate their classic protein kinase counterparts. In the present review, we discuss members of the human pseudokinome repertoire, and catalogue somatic amino acid pseudokinase mutations that are emerging as the depth and clinical coverage of the human cancer pseudokinome expand.
The proteins of exocytosis: lessons from the sperm model
Authors: Tomes Claudia Nora
Published: January 2015

Exocytosis is a highly regulated process that consists of multiple functionally, kinetically and/or morphologically definable stages such as recruitment, targeting, tethering and docking of secretory vesicles with the plasma membrane, priming of the fusion machinery and calcium-triggered membrane fusion. After fusion, the membrane around the secretory vesicle is incorporated into the plasma membrane and the granule releases its contents. The proteins involved in these processes belong to several highly conserved families: Rab GTPases, SNAREs (soluble NSF-attachment protein receptors), α-SNAP (α-NSF attachment protein), NSF (N-ethylmaleimide-sensitive factor), Munc13 and -18, complexins and synaptotagmins. In the present article, the molecules of exocytosis are reviewed, using human sperm as a model system. Sperm exocytosis is driven by isoforms of the same proteinaceous fusion machinery mentioned above, with their functions orchestrated in a hierarchically organized and unidirectional signalling cascade. In addition to the universal exocytosis regulator calcium, this cascade includes other second messengers such as diacylglycerol, inositol 1,4,5-trisphosphate and cAMP, as well as the enzymes that synthesize them and their target proteins. Of special interest is the cAMP-binding protein Epac (exchange protein directly activated by cAMP) due in part to its enzymatic activity towards Rap. The activation of Epac and Rap leads to a highly localized calcium signal which, together with assembly of the SNARE complex, governs the final stages of exocytosis. The source of this releasable calcium is the secretory granule itself.
Ischaemia-induced autophagy leads to degradation of gap junction protein connexin43 in cardiomyocytes
Authors: Martins-Marques Tania , Catarino Steve , Zuzarte Monica , Marques Carla , Matafome Paulo , Pereira Paulo , Girão Henrique
Published: January 2015

In this study we demonstrate that ischemia-induced impairment of intercellular communication between cardiomyocytes is due to the degradation of the gap junction protein Connexin43 by autophagy, which according to the severity of the insult involves different molecular partners.
Optimal user‐centric relay assisted device‐to‐device communications: an auction approach
Authors: Chen Yichao , He Shibo , Hou Fen , Shi Zhiguo , Chen Xu
Published: January 2015

Device‐to‐device (D2D) communication has recently attracted much research attention because of its potential to increase the capacity of cellular networks. Most existing works aim to maximise the overall system throughput (system‐centric), which ignores the actual traffic demands of D2D users. In this study, the authors consider user‐centric relay assisted D2D communications where D2D users have different evaluations for the significance of every unit of increased data rate. By considering the traffic demands of D2D users, the authors propose a Vickrey–Clarke–Groves auction based relay allocation mechanism (ARM) in which every D2D user submits a bid to the basestation (BS). The submitted bids indicate D2D users’ valuation on every unit of the increased data rate. The BS then allocates relays to D2D users by maximising the social welfare of D2D users while maintaining a predefined data rate requirement for cellular users. A payment scheme to charge D2D users for using relays is designed, and the authors show that the auction is truthful. The authors also extend the results to a general case and provide a general ARM accordingly. Extensive simulation results are provided to demonstrate the performance of the proposed mechanisms.
Control and dynamic analysis of a parallel‐connected single active bridge DC–DC converter for DC‐grid wind farm application
Authors: Park Kiwoo , Chen Zhe
Published: January 2015

This study presents a control strategy and its dynamic analysis of a high‐power dc–dc converter, which is constructed with the parallel‐connected single active bridge (SAB) dc–dc converters for dc‐grid wind farm applications. The structural and operational characteristics of the SAB dc–dc converter have several advantages for high‐power applications, and the modular concept of the parallel‐connected converter is highly beneficial especially for offshore wind farm applications in terms of maintenance cost and fault tolerance. To justify the feasibility of the parallel‐connected SAB dc–dc converter for dc‐grid wind farm applications, an input voltage control method based on the PI control will be introduced and the dynamics of the overall system will be analysed. The analysis results are to be verified by means of simulations and experiments.
A compact electron gun for time-resolved electron diffraction
Authors: Robinson Matthew S. , Lane Paul D. , Wann Derek A.
Published: January 2015

A novel compact time-resolved electron diffractometer has been built with the primary goal of studying the ultrafast molecular dynamics of photoexcited gas-phase molecules. Here, we discuss the design of the electron gun, which is triggered by a Ti:Sapphire laser, before detailing a series of calibration experiments relating to the electron-beam properties. As a further test of the apparatus, initial diffraction patterns have been collected for thin, polycrystalline platinum samples, which have been shown to match theoretical patterns. The data collected demonstrate the focusing effects of the magnetic lens on the electron beam, and how this relates to the spatial resolution of the diffraction pattern.
The problem of two fixed centers: bifurcation diagram for positive energies
Authors: Seri Marcello
Published: January 2015

We give a comprehensive analysis of the Euler-Jacobi problem of motion in the field of two fixed centers with arbitrary relative strength and for positive values of the energy. These systems represent nontrivial examples of integrable dynamics and are analysed from the point of view of the energy-momentum mapping from the phase space to the space of the integration constants. In this setting, we describe the structure of the scattering trajectories in phase space and derive an explicit description of the bifurcation diagram, i.e., the set of critical value of the energy-momentum map.
Differential and integral cross sections in OH(X) + Xe collisions
Authors: Sarma Gautam , Saha Ashim Kumar , ter Meulen J. J. , Parker David H. , Marinakis Sarantos
Published: January 2015

Differential cross sections (DCSs) for inelastic collisions of OH(X) with Xe have been measured at a collision energy of 483 cm−1. The hydroxyl (OH) radicals were initially prepared in the X2Π3/2 (v = 0, j = 1.5, f) level using the hexapole electric field selection method. Products were detected state-selectively by [2 + 1] resonance-enhanced multiphoton ionization of OH, combined with velocity-map imaging. Integral cross sections in OH(X) + Xe at a collision energy of 490 cm−1 were also measured by laser-induced fluorescence. The results are compared with exact close-coupling quantum mechanical scattering calculations on the only available ab initio potential energy surface (PES). The agreement between experimental and theoretical results is generally very satisfactory. This highlights the ability of such measurements to test the available PES for such a benchmark open-shell system. The agreement between experiment and theory for DCSs is less satisfactory at low scattering angles, and possible reasons for this disagreement are discussed. Finally, theoretical calculations of OH(X) + He DCSs have been obtained at various collision energies and are compared with those of OH(X) + Xe. The role of the reduced mass in the DCSs and partial cross sections is also examined.
Global dynamics and inflationary center manifold and slow-roll approximants
Authors: Alho Artur , Uggla Claes
Published: January 2015

We consider the familiar problem of a minimally coupled scalar field with quadratic potential in flat Friedmann-Lemaître-Robertson-Walker cosmology to illustrate a number of techniques and tools, which can be applied to a wide range of scalar field potentials and problems in, e.g., modified gravity. We present a global and regular dynamical systems description that yields a global understanding of the solution space, including asymptotic features. We introduce dynamical systems techniques such as center manifold expansions and use Padé approximants to obtain improved approximations for the “attractor solution” at early times. We also show that future asymptotic behavior is associated with a limit cycle, which shows that manifest self-similarity is asymptotically broken toward the future and gives approximate expressions for this behavior. We then combine these results to obtain global approximations for the attractor solution, which, e.g., might be used in the context of global measures. In addition, we elucidate the connection between slow-roll based approximations and the attractor solution, and compare these approximations with the center manifold based approximants.
Range effect on percolation threshold and structural properties for short-range attractive spheres
Authors: Wei Jiachen , Xu Limei , Song Fan
Published: January 2015

Percolation or aggregation in colloidal system is important in many fields of science and technology. Using molecular dynamics simulations, we study the percolation behavior for systems consisting of spheres interacting with short-range square-well (SRSW) which mimic colloidal particles, with different interaction ranges. We specifically focus on how the interaction range affects the percolation thresholds in the supercritical region. We find that the contact percolation boundaries are strongly dependent on the interaction ranges of SRSW, especially away from the liquid-liquid critical point. However, varying the interaction ranges of SRSW does not affect much the structure along percolation boundaries especially for low packing fractions. For instance, along the percolation boundary, distributions of coordination number show convergence, and distributions of cluster size are universal for different interaction ranges considered. In addition, either the bond percolation boundaries or isolines of average bond coordination number collapse to those for Baxter sticky model on phase diagram, which confirms the extended law of corresponding states.
A point vortex model for the formation of ocean eddies by flow separation
Authors: Southwick O. R. , Johnson E. R. , McDonald N. R.
Published: January 2015

A simple model for the formation of ocean eddies by flow separation from sharply curved horizontal boundary topography is developed. This is based on the Brown–Michael model for two-dimensional vortex shedding, which is adapted to more realistically model mesoscale oceanic flow by including a deforming free surface. With a free surface, the streamfunction for the flow is not harmonic so the conformal mapping methods used in the standard Brown–Michael approach cannot be used and the problem must be solved numerically. A numerical scheme is developed based on a Chebyshev spectral method for the streamfunction partial differential equation and a second order implicit timestepping scheme for the vortex position ordinary differntial equations. This method is used to compute shed vortex trajectories for three background flows: (A) a steady flow around a semi-infinite plate, (B) a free vortex moving around a semi-infinite plate, and (C) a free vortex moving around a right-angled wedge. In (A), the inclusion of surface deformation dramatically slows the vortex and changes its trajectory from a straight path to a curved one. In (B) and (C), without the inclusion of flow separation, free vortices traverse fully around the tip along symmetrical trajectories. With the effects of flow separation included, very different trajectories are found: for all values of the model parameter—the Rossby radius—the free and shed vortices pair up and move off to infinity without passing around the tip. Their final propagation angle depends strongly and monotonically on the Rossby radius.
Electrophilic surface sites as precondition for the chemisorption of pyrrole on GaAs(001) surfaces
Authors: Bruhn Thomas , Fimland Bjørn-Ove , Vogt Patrick
Published: January 2015

We report how the presence of electrophilic surface sites influences the adsorption mechanism of pyrrole on GaAs(001) surfaces. For this purpose, we have investigated the adsorption behavior of pyrrole on different GaAs(001) reconstructions with different stoichiometries and thus different surface chemistries. The interfaces were characterized by x-ray photoelectron spectroscopy, scanning tunneling microscopy, and by reflectance anisotropy spectroscopy in a spectral range between 1.5 and 5 eV. On the As-rich c(4 × 4) reconstruction that exhibits only nucleophilic surface sites, pyrrole was found to physisorb on the surface without any significant modification of the structural and electronic properties of the surface. On the Ga-rich GaAs(001)-(4 × 2)/(6 × 6) reconstructions which exhibit nucleophilic as well as electrophilic surface sites, pyrrole was found to form stable covalent bonds mainly to the electrophilic (charge deficient) Ga atoms of the surface. These results clearly demonstrate that the existence of electrophilic surface sites is a crucial precondition for the chemisorption of pyrrole on GaAs(001) surfaces.
Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): Time-resolved fluorescence measurements and all-atom molecular dynamics simulations
Authors: Das Anuradha , Das Suman , Biswas Ranjit
Published: January 2015

Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH3CONH2) and urea (NH2CONH2) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH3CONH2 + (1 − f)NH2CONH2] have been studied in a temperature range of 328-353 K which is ∼120-145 K above the measured glass transition temperatures (∼207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (∼70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (α2) and new non-Gaussian (γ) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems.
On the effective mobility extraction by point-contact techniques on silicon-on-insulator substrates
Authors: Fernandez Cristina , Rodriguez Noel , Marquez Carlos , Ohata Akiko , Allibert Frederic
Published: January 2015

In this work, we introduce the mobility vs. effective electric field representation for bare silicon-on-insulator substrates. The key factors determining the effective field in the silicon film are identified and modeled. This representation sheds light on the origins of the carrier mobility differences observed in passivated and non-passivated wafers. At low effective electric field, the roles of the Coulomb scattering, determined by the top-interface, and the impact of the silicon film thickness are clearly disclosed. Two and four point-contact characterization techniques are compared; caution is called when the two point Pseudo-MOSFET configuration is used without calibration of the current form factor, since it may lead to an underestimation of the mobility values. Nevertheless, when the effective field and current form factors are evaluated accurately, we report that the carrier mobility of the silicon film at high effective electric field, with passivated surface or not, obeys the Universal Mobility Curves.
Terahertz magneto-optical spectroscopy of a two-dimensional hole gas
Authors: Kamaraju N. , Pan W. , Ekenberg U. , Gvozdić D. M. , Boubanga-Tombet S. , Upadhya P. C. , Reno J. , Taylor A. J. , Prasankumar R. P.
Published: January 2015

Two-dimensional hole gases (2DHGs) have attracted recent attention for their unique quantum physics and potential applications in areas including spintronics and quantum computing. However, their properties remain relatively unexplored, motivating the use of different techniques to study them. We used terahertz magneto-optical spectroscopy to investigate the cyclotron resonance frequency in a high mobility 2DHG, revealing a nonlinear dependence on the applied magnetic field. This is shown to be due to the complex non-parabolic valence band structure of the 2DHG, as verified by multiband Landau level calculations. We also find that impurity scattering dominates cyclotron resonance decay in the 2DHG, in contrast with the dominance of superradiant damping in two-dimensional electron gases. Our results shed light on the properties of 2DHGs, motivating further studies of these unique 2D nanosystems.
Nano suboxide layer generated in Ta2O5 by Ar+ ion irradiation
Authors: Song W. D. , Ying J. F. , He W. , Zhuo V. Y.-Q. , Ji R. , Xie H. Q. , Ng S. K. , Ng Serene L. G. , Jiang Y.
Published: January 2015

Ta2O5/TaOx heterostructure has become a leading oxide layer in memory cells and/or a bidirectional selector for resistive random access memory (RRAM). Although atomic layer deposition (ALD) was found to be uniquely suitable for depositing uniform and conformal films on complex topographies, it is hard to use ALD to grow suboxide TaOx layer. In this study, tantalum oxide films with a composition of Ta2O5 were grown by ALD. Using Ar+ ion irradiation, the suboxide was formed in the top layer of Ta2O5 films by observing the Ta core level shift toward lower binding energy with angle-resolved X-ray photoelectron spectroscopy. By controlling the energy and irradiation time of an Ar+ ion beam, Ta2O5/TaOx heterostructure can be reliably produced on ALD films, which provides a way to fabricate the critical switching layers of RRAM.
Enhanced photocurrent of Ge-doped InGaO thin film transistors with quantum dots
Authors: Lee Sang Moo , Park Si Jin , Lee Kwang Ho , Park Jin-Seong , Park Soohyung , Yi Yeonjin , Kang Seong Jun
Published: January 2015

The photocurrent of germanium-doped indium-gallium oxide (GIGO) thin film transistors (TFTs) can be observed when the device is exposed to a ultra-violet light because GIGO is a wide band gap semiconducting material. Therefore, we decorated cadmium selenide (CdSe) quantum-dots (QDs) on the surface of GIGO to increase the photocurrent for low-energy light, i.e., visible light. A 10 nm GIGO film was deposited on the SiO2/Si substrate by a radio frequency sputter system. Also, we prepared CdSe QDs with sizes of ∼6.3 nm, which can absorb red visible light. QDs were spin-coated onto the GIGO film, and post-annealing was done to provide cross-linking between QDs. The prepared devices showed a 231% increase in photocurrent when exposed to 650 nm light due to the QDs on the GIGO surface. Measurements to construct an energy level diagram were made using ultraviolet photoelectron spectroscopy to determine the origin of the photocurrent, and we found that the small band gap of CdSe QDs enables the increase in photocurrent in the GIGO TFTs. This result is relevant for developing highly transparent photosensors based on oxide semiconductors and QDs.
Phaseguide-assisted blood separation microfluidic device for point-of-care applications
Authors: Xu Linfeng , Lee Hun , Brasil Pinheiro Mariana Vanderlei , Schneider Phil , Jetta Deekshitha , Oh Kwang W.
Published: January 2015

We propose a blood separation microfluidic device suitable for point-of-care (POC) applications. By utilizing the high gas permeability of polydimethylsiloxane (PDMS) and phaseguide structures, a simple blood separation device is presented. The device consists of two main parts. A separation chamber with the phaseguide structures, where a sample inlet, a tape-sealed outlet, and a dead-end ring channel are connected, and pneumatic chambers, in which manually operating syringes are plugged. The separation chamber and pneumatic chambers are isolated by a thin PDMS wall. By manually pulling out the plunger of the syringe, a negative pressure is instantaneously generated inside the pneumatic chamber. Due to the gas diffusion from the separation chamber to the neighboring pneumatic chamber through the thin permeable PDMS wall, low pressure can be generated, and then the whole blood at the sample inlets starts to be drawn into the separation chamber and separated through the phaseguide structures. Reversely, after removing the tape at the outlet and manually pushing in the plunger of the syringe, a positive pressure will be created which will cause the air to diffuse back into the ring channel, and therefore allow the separated plasma to be recovered at the outlet on demand. In this paper, we focused on the study of the plasma separation and associated design parameters, such as the PDMS wall thickness, the air permeable overlap area between the separation and pneumatic chambers, and the geometry of the phaseguides. The device required only 2 μl of whole blood but yielding approximately 0.38 μl of separated plasma within 12 min. Without any of the requirements of sophisticated equipment or dilution techniques, we can not only separate the plasma from the whole blood for on-chip analysis but also can push out only the separated plasma to the outlet for off-chip analysis.