bluuebunny/crossref_metadata_2025 huggingface dataset:
A universal mechanism of extreme events and critical phenomena
Authors: Wu J. H. , Jia Q.
Published: February 2016

The occurrence of extreme events and critical phenomena is of importance because they can have inquisitive scientific impact and profound socio-economic consequences. Here we show a universal mechanism describing extreme events along with critical phenomena and derive a general expression of the probability distribution without concerning the physical details of individual events or critical properties. The general probability distribution unifies most important distributions in the field and demonstrates improved performance. The shape and symmetry of the general distribution is determined by the parameters of the fluctuations. Our work sheds judicious insights into the dynamical processes of complex systems with practical significance and provides a general approach of studying extreme and critical episodes in a combined and multidisciplinary scheme.
An integrative approach to phylogeny reveals patterns of environmental distribution and novel evolutionary relationships in a major group of ciliates
Authors: Sun Ping , Clamp John , Xu Dapeng , Huang Bangqin , Shin Mann Kyoon
Published: February 2016

Peritrichs are a major group of ciliates with worldwide distribution. Yet, its internal phylogeny remains unresolved owing to limited sampling. Additionally, ecological distributions of peritrichs are poorly known. We performed substantially expanded phylogenetic analyses of peritrichs that incorporated SSU rDNA sequences of samples collected from three continents, revealing a number of new relationships between and within major lineages that greatly challenged the classic view of the group. Interrogation of a dataset comprising new environmental sequences from an estuary and the open ocean generated with high throughput sequencing and clone libraries plus putative environmental peritrich sequences at Genbank, produced a comprehensive tree of peritrichs from a variety of habitats and revealed unique ecological distribution patterns of several lineages for the first time. Also, evidence of adaptation to extreme environments in the Astylozoidae clade greatly broadened the phylogenetic range of peritrichs capable of living in extreme environments. Reconstruction of ancestral states revealed that peritrichs may have transitioned repeatedly from freshwater to brackish/marine/hypersaline environments. This work establishes a phylogenetic framework for more mature investigations of peritrichs in the future, and the approach used here provides a model of how to elucidate evolution in the context of ecological niches in any lineage of microbial eukaryotes.
A jumping shape memory alloy under heat
Authors: Yang Shuiyuan , Omori Toshihiro , Wang Cuiping , Liu Yong , Nagasako Makoto , Ruan Jingjing , Kainuma Ryosuke , Ishida Kiyohito , Liu Xingjun
Published: February 2016

Shape memory alloys are typical temperature-sensitive metallic functional materials due to superelasticity and shape recovery characteristics. The conventional shape memory effect involves the formation and deformation of thermally induced martensite and its reverse transformation. The shape recovery process usually takes place over a temperature range, showing relatively low temperature-sensitivity. Here we report novel Cu-Al-Fe-Mn shape memory alloys. Their stress-strain and shape recovery behaviors are clearly different from the conventional shape memory alloys. In this study, although the Cu-12.2Al-4.3Fe-6.6Mn and Cu-12.9Al-3.8Fe-5.6Mn alloys possess predominantly L21 parent before deformation, the 2H martensite stress-induced from L21 parent could be retained after unloading. Furthermore, their shape recovery response is extremely temperature-sensitive, in which a giant residual strain of about 9% recovers instantly and completely during heating. At the same time, the phenomenon of the jumping of the sample occurs. It is originated from the instantaneous completion of the reverse transformation of the stabilized 2H martensite. This novel Cu-Al-Fe-Mn shape memory alloys have great potentials as new temperature-sensitive functional materials.
LGI1 acts presynaptically to regulate excitatory synaptic transmission during early postnatal development
Authors: Boillot Morgane , Lee Chun-Yao , Allene Camille , Leguern Eric , Baulac Stéphanie , Rouach Nathalie
Published: February 2016

The secreted leucine-rich glioma inactivated 1 (LGI1) protein is an important actor for human seizures of both genetic and autoimmune etiology: mutations in LGI1 cause inherited temporal lobe epilepsy, while LGI1 is involved in antibody-mediated encephalitis. Remarkably, Lgi1-deficient (Lgi1−/−) mice recapitulate the epileptic disorder and display early-onset spontaneous seizures. To understand how Lgi1-deficiency leads to seizures during postnatal development, we here investigated the early functional and structural defects occurring before seizure onset in Lgi1−/− mice. We found an increased excitatory synaptic transmission in hippocampal slices from Lgi1−/− mice. No structural alteration in the morphology of pyramidal cell dendrites and synapses was observed at this stage, indicating that Lgi1-deficiency is unlikely to trigger early developmental abnormalities. Consistent with the presynaptic subcellular localization of the protein, Lgi1-deficiency caused presynaptic defects, with no alteration in postsynaptic AMPA receptor activity in Lgi1−/− pyramidal cells before seizure onset. Presynaptic dysfunction led to increased synaptic glutamate levels, which were associated with hyperexcitable neuronal networks. Altogether, these data show that Lgi1 acts presynaptically as a negative modulator of excitatory synaptic transmission during early postnatal development. We therefore here reveal that increased presynaptic glutamate release is a key early event resulting from Lgi1-deficiency, which likely contributes to epileptogenesis.
AKT1 genotype moderates the acute psychotomimetic effects of naturalistically smoked cannabis in young cannabis smokers
Authors: Morgan C J A , Freeman T P , Powell J , Curran H V
Published: February 2016

Smoking cannabis daily doubles an individual’s risk of developing a psychotic disorder, yet indicators of specific vulnerability have proved largely elusive. Genetic variation is one potential risk modifier. Single-nucleotide polymorphisms in the AKT1 and catechol-O-methyltransferase (COMT) genes have been implicated in the interaction between cannabis, psychosis and cognition, but no studies have examined their impact on an individual’s acute response to smoked cannabis. A total 442 healthy young cannabis users were tested while intoxicated with their own cannabis—which was analysed for delta-9-tetrahydrocannbinol (THC) and cannabidiol content—and also ±7 days apart when drug-free. Psychotomimetic symptoms and working memory were assessed on both the sessions. Variation at the rs2494732 locus of the AKT1 gene predicted acute psychotic response to cannabis along with dependence on the drug and baseline schizotypal symptoms. Working memory following cannabis acutely was worse in females, with some suggestion of an impact of COMT polymorphism on working memory when drug-free. These findings are the first to demonstrate that AKT1 mediates the acute response to cannabis in otherwise healthy individuals and implicate the AKT1 pathway as a possible target for prevention and treatment of cannabis psychosis.
Uncharged nucleoside inhibitors of β-1,4-galactosyltransferase with activity in cells
Authors: Jiang Jingqian , Kanabar Varsha , Padilla Beatriz , Man Francis , Pitchford Simon C. , Page Clive P. , Wagner Gerd K.
Published: February 2016

5-Substituted uridine derivatives are uncharged galactosyltransferase inhibitors that reduce PSGL-1 expression in human monocytes.
Electronic and magnetic properties of SnSe monolayers doped by Ga, In, As, and Sb: a first-principles study
Authors: Wang Qingxia , Yu Weiyang , Fu Xiaonan , Qiao Chong , Xia Congxin , Jia Yu
Published: February 2016

A SnSe monolayer with an orthorhombic Pnma GeS structure is an important two-dimensional (2D) indirect band gap material at room temperature.
Cage effects on conformational preference and photophysics in the host–guest complex of benzenediols with 18-Crown-6
Authors: Morishima Fumiya , Kusaka Ryoji , Inokuchi Yoshiya , Haino Takeharu , Ebata Takayuki
Published: February 2016

The conformational preference and modification of photophysics of benzenediols, namely hydroquinone (HQ), resorcinol (RE) and catechol (CA), upon host–guest complex formation with 18-Crown-6 (18C6) have been investigated, under supersonically jet-cooled conditions.
Proton transfer aiding phase transitions in oxalic acid dihydrate under pressure
Authors: Bhatt Himal , Mishra A. K. , Murli Chitra , Verma Ashok K. , Garg Nandini , Deo M. N. , Sharma Surinder M.
Published: February 2016

The strengthening of hydrogen bonds is favored by the cooperative effect in oxalic acid dihydrate. Pressure induced proton transfer restricts the water oxygen to be an acceptor of hydrogen bonds and ionizes the local structural moieties.
Complex interfaces in “phase-change” contrast agents
Authors: Capece Sabrina , Domenici Fabio , Brasili Francesco , Oddo Letizia , Cerroni Barbara , Bedini Angelico , Bordi Federico , Chiessi Ester , Paradossi Gaio
Published: February 2016

In this paper we report on the study of the interface of hybrid shell droplets encapsulating decafluoropentane (DFP), which exhibit interesting potentialities for ultrasound (US) imaging.
Optical and grain boundary potential characteristics of sulfurized BiFeO3 thin films for photovoltaic applications
Authors: Lee Seung Min , Cho Yong Soo
Published: February 2016

Sulfurized BiFeO3 (BFO) thin films have been investigated with the purpose of reducing their band gap for photovoltaic applications.
Site-specific metal and ligand substitutions in a microporous Mn2+-based metal–organic framework
Authors: Huxley Michael , Coghlan Campbell J. , Burgun Alexandre , Tarzia Andrew , Sumida Kenji , Sumby Christopher J. , Doonan Christian J.
Published: February 2016

Mixed-ligand syntheses and post-synthetic metal exchange performed on the Mn3L3 structure type results in site-specific manipulations to the framework structure.
A redox flow lithium battery based on the redox targeting reactions between LiFePO4and iodide
Authors: Huang Qizhao , Yang Jing , Ng Chee Boon , Jia Chuankun , Wang Qing
Published: February 2016

Charge/discharge LiFeO4with a single redox species: a Li-I redox flow lithium battery with strikingly high energy density for large-scale energy storage applications.
Antibacterial activity of isolated phenolic compounds from cranberry (Vaccinium macrocarpon) against Escherichia coli
Authors: Rodríguez-Pérez Celia , Quirantes-Piné Rosa , Uberos José , Jiménez-Sánchez Cecilia , Peña Alejandro , Segura-Carretero Antonio
Published: February 2016

Apart from proanthocyanidins, isolated polyphenols from cranberry can act againstE. coliadherence and/or modify its surface hydrophobicityin vitro.
Transketolase catalysed upgrading ofl-arabinose: the one-step stereoselective synthesis ofl-gluco-heptulose
Authors: Subrizi Fabiana , Cárdenas-Fernández Max , Lye Gary J. , Ward John M. , Dalby Paul A. , Sheppard Tom D. , Hailes Helen C.
Published: February 2016

Biocatalytic conversions usingE. colitransketolase variants have been developed for the efficient, scalable synthesis ofl-gluco-heptulose from the sustainable starting materiall-arabinose.
A photostable fluorescent probe for rapid monitoring and tracking of a trans-membrane process and mitochondrial fission and fusion dynamics
Authors: Liu Yong , Meng Fangfang , Tang Yonghe , Yu Xiaoqiang , Lin Weiying
Published: February 2016

The MT-PVIM probe was capable of monitoring and tracking a trans membrane process and mitochondrial fission and fusion dynamics.
Conductive silver patterns on polyimide substrates by using an alkali paint modification–ion exchange–reduction (AIR) process via low requirements mask technology
Authors: Wang Yanqing , Li Ning , Li Deyu
Published: February 2016

We fabricate conductive single-side and double-sided silver patterns in one step by using an AIR process via low requirements mask technology.
Phospholipid–silica mesophases formed in hydroalcoholic solution as precursors of mesoporous silica
Authors: Toumi Nadia , Bégu Sylvie , Cacciaguerra Thomas , Galarneau Anne , Azaïs Thierry , Bengueddach Abdelkader , Renzo Francesco Di
Published: February 2016

The fusion of lipid bilayers in sponge silica–lecithin composites is favoured by natural cosurfactants-induced local opposite curvatures.
Fabrication of cubic Zn2SnO4/SnO2 complex hollow structures and their sunlight-driven photocatalytic activity
Authors: Sun Linqiang , Han Xiao , Jiang Zhe , Ye Tingting , Li Rong , Zhao Xinsheng , Han Xiguang
Published: February 2016

Uniform hollow, yolk–shell and double-shell Zn2SnO4/SnO2 nanoparticles with cubic morphologies have been synthesized using “etching–second growth–annealed” methods. Double-shell structures show an obvious improvement in photocatalytic activity.
Palladium(ii) and copper(ii) chloride complexes bearing bulky α-diimine ligands as catalysts for norbornene vinyl-addition (co)polymerization
Authors: Tian Jianwen , He Xiaohui , Liu Jingyin , Deng Xiaodan , Chen Defu
Published: February 2016

Palladium(ii) and copper(ii) chloride complexes bearing bulky 9,10-dihydro-9,10-ethanoanthracene-11,12-diimine ligands were synthesized and sufficiently characterized by elemental and spectroscopic analysis along with X-ray diffraction analysis.
Indigenous north eastern India fern mediated fabrication of spherical silver and anisotropic gold nano structured materials and their efficacy for the abatement of perilous organic compounds from waste water-A green approach
Authors: Sinha Tanur , Ahmaruzzaman M.
Published: February 2016

Herein, we presented a hitherto unexplored native fern of north eastern India; Diplazium esculentum mediated biogenic fabrication of spherical silver and anisotropic gold nano structured materials.
Lanthanide-based coordination polymers as promising heterogeneous catalysts for ring-opening reactions
Authors: Kumar Gulshan , Kumar Girijesh , Gupta Rajeev
Published: February 2016

Eu and Tb based coordination polymers function as reusable heterogeneous catalysts for ring-opening reactions with amines, alcohols, thiols, and azides as nucleophiles.
Simple and signal-off electrochemiluminescence immunosensor for alpha fetoprotein based on gold nanoparticle-modified graphite-like carbon nitride nanosheet nanohybrids
Authors: Zheng Xiangli , Hua Xiaoxia , Qiao Xueying , Xia Fangquan , Tian Dong , Zhou Changli
Published: February 2016

A simple, signal-off electrochemiluminescence immunosensor for sensitive and selective detection of alpha fetoprotein was developed based on gold nanoparticle modified graphite-like carbon nitride nanosheet nanohybrids.
2-Amino-4-aryl thiazole: a promising scaffold identified as a potent 5-LOX inhibitor
Authors: Sinha Shweta , Sravanthi T. V. , Yuvaraj S. , Manju S. L. , Doble Mukesh
Published: February 2016

Human 5-lipoxygenase (5-LOX) is a target for asthma and allergy treatment. Zileuton is the only marketed drug targeting this enzyme (IC50∼ 1 μM). The current study identifies a promising lead molecule which could be improved to match the activity of zileuton.
Hairpin ribozyme mediated RNA recombination
Authors: Hieronymus Robert , Godehard Simon Peter , Balke Darko , Müller Sabine
Published: February 2016

An engineered hairpin ribozyme supports the recombination of two non-functional substrates into a functional hammerhead ribozyme.
PdII/CuBr2 catalysed keto α-Csp3–H benzoxylation of N,N-dialkylamides directed by o-hydroxy groups
Authors: Santra Sourav Kumar , Banerjee Arghya , Rajamanickam Suresh , Khatun Nilufa , Patel Bhisma K.
Published: February 2016

A hydroxy group directed keto α-Csp3–H benzoxylation of N,N-dialkylamides has been accomplished with a Pd(ii)/CuBr2 catalytic combination.
Enantioselective synthesis of adamantylalanine and carboranylalanine and their incorporation into the proteasome inhibitor bortezomib
Authors: de Bruin Gerjan , Mock Elliot D. , Hoogendoorn Sascha , van den Nieuwendijk Adrianus M. C. H. , Mazurek Jaroslaw , van der Marel Gijsbert A. , Florea Bogdan I. , Overkleeft Herman S.
Published: February 2016

We have developed new syntheses for adamantyl- and carboranylalanine. Their incorporation in bortezomib provided potent proteasome inhibitors with high off-rates.
DNA base-stacking assay utilizing catalytic hairpin assembly-induced gold nanoparticle aggregation for colorimetric protein sensing
Authors: Chang Chia-Chen , Chen Chie-Pein , Chen Chen-Yu , Lin Chii-Wann
Published: February 2016

A label-free and enzyme-free colorimetric sensing platform for the amplified detection of fibronectin was developed based on an ingenious combination of catalytic hairpin assembly and a base stacking hybridization-based gold nanoparticle aggregation strategy.
Pleurotus nebrodensis polysaccharide(PN50G) evokes A549 cell apoptosis by the ROS/AMPK/PI3K/AKT/mTOR pathway to suppress tumor growth
Authors: Cui Haiyan , Wu Shufen , Shang Yunfei , Li Zhenjing , Chen Mianhua , Li Fengjuan , Wang Changlu
Published: February 2016

The model for PN50G mediated signal transduction pathways in the regulation of tumor apoptosis in A549-bearing mice is proposed.
Pyrosequencing on a glass surface
Authors: Almeida Ana V. , Manz Andreas , Neužil Pavel
Published: February 2016

We demonstrated DNA pyrosequencing at the plain hydrophobically coated surface of a microscope glass cover slip using open-surface microfluidics.
Intrinsic reactivity profile of electrophilic moieties to guide covalent drug design: N-α-acetyl-l-lysine as an amine nucleophile
Authors: Dahal Upendra P. , Gilbert Adam M. , Obach R. Scott , Flanagan Mark E. , Chen Jinshan M. , Garcia-Irizarry Carmen , Starr Jeremy T. , Schuff Brandon , Uccello Daniel P. , Young Jennifer A.
Published: February 2016

Covalent drugs contain a reactive electrophilic moiety or covalent reactive group (CRG), which forms an irreversible bond between the drug and a biological target.
Expanding the library of divalent fucosidase inhibitors with polyamino and triazole-benzyl bridged bispyrrolidines
Authors: Hottin Audrey , Carrión-Jiménez Sebastián , Moreno-Clavijo Elena , Moreno-Vargas Antonio J. , Carmona Ana T. , Robina Inmaculada , Behr Jean-Bernard
Published: February 2016

A small library of divalent fucosidase inhibitors containing pyrrolidine motifs were prepared and evaluated as α-fucosidase inhibitors.
Enhanced electroactive β-phase nucleation and dielectric properties of PVdF-HFP thin films influenced by montmorillonite and Ni(OH)2 nanoparticle modified montmorillonite
Authors: Roy Swagata , Thakur Pradip , Hoque Nur Amin , Bagchi Biswajoy , Das Sukhen
Published: February 2016

Enhancement of β-phase nucleation and dielectric properties of PVdF-HFP films due to incorporation of montmorillonite and Ni(OH)2 nanoparticle modified montmorillonite.
Nanoscale porous triazine-based frameworks with cyanate ester linkages for efficient drug delivery
Authors: Liu Junling , Fu Yu , Fu Xianbo , Li Yuxin , Liang Dongke , Song Yuan , Pan Chunyue , Yu Guipeng , Xiao Xuxian
Published: February 2016

An easy modulation of the pore size of cyanate ester resins allows amount of inserted drug and its release behavior that depend on pore size and host–drug interactions rather than the surface controllable.
Unique walnut-shaped porous MnO2/C nanospheres with enhanced reaction kinetics for lithium storage with high capacity and superior rate capability
Authors: Huang Shao-Zhuan , Cai Yi , Jin Jun , Liu Jing , Li Yu , Wang Hong-En , Chen Li-Hua , Hasan Tawfique , Su Bao-Lian
Published: February 2016

Unique walnut-shaped porous MnO2/carbon nanospheres via in situ carbonization of amorphous MnO2 nanospheres demonstrate enhanced reaction kinetics for lithium storage.
Ethyl viologen dibromide as a novel dual redox shuttle for supercapacitors
Authors: Sathyamoorthi Sethuraman , Kanagaraj M. , Kathiresan Murugavel , Suryanarayanan V. , Velayutham D.
Published: February 2016

Viologen (1,1ʹ-diethyl-4,4ʹ-bipyridinium bromide) based redox active electrolyte in 1.0 M H2SO4 has been proposed as a novel electrolyte for supercapacitor (SC) applications due to its dual cathodic and anodic redox behaviour.
Preparation of zirconia‐doped titania superacid and its application in viscosity reduction of heavy oil
Authors: Li Yiguang , Liu Xueliang , Li Xiaohong , Zhang Zhijun , Zhao Mengyun , Su Changming
Published: February 2016

Sulphated titania superacid (denoted as SO42−/TiO2) and sulphated zirconia‐doped titania superacid (denoted as SO42−/ZrO2/TiO2) were prepared via a liquid‐phase in‐situ method. As‐prepared SO42−/TiO2 and SO42−/ZrO2/TiO2 superacids were characterised by transmission electron microscopy, field emission scanning electron microscopy, X‐ray diffraction and Fourier transform infrared spectrometry. Moreover, the catalytic performance of SO42−/TiO2 and SO42−/ZrO2/TiO2 for the aquathermolysis reaction and viscosity reduction of the extra‐heavy oil recovered at Shengli Oilfield (Dongying, China) was investigated. It was found that SO42−/TiO2 and SO42−/ZrO2/TiO2 as the catalysts for the aquathermolysis process of the tested extra‐heavy oil have good catalytic performance. Saturated hydrocarbon, aromatic hydrocarbon, resin and asphalt composition of the tested heavy oil sample before and after aquathermolysis reaction indicates that the amount of the saturated hydrocarbon and aromatic hydrocarbon are increased, while the amount of resin and asphalt are decreased, showing promising potential in the industrial production of heavy crude oil.
Ultrahigh efficiencies in vertical epitaxial heterostructure architectures
Authors: Fafard S. , York M. C. A. , Proulx F. , Valdivia C. E. , Wilkins M. M. , Arès R. , Aimez V. , Hinzer K. , Masson D. P.
Published: February 2016

Optical to electrical power converting semiconductor devices were achieved with breakthrough performance by designing a Vertical Epitaxial Heterostructure Architecture. The devices are featuring modeled and measured conversion efficiencies greater than 65%. The ultrahigh conversion efficiencies were obtained by monolithically integrating several thin GaAs photovoltaic junctions tailored with submicron absorption thicknesses and grown in a single crystal by epitaxy. The heterostructures that were engineered with a number N of such ultrathin junctions yielded an optimal external quantum efficiencies approaching 100%/N. The heterostructures are capable of output voltages that are multiple times larger than the corresponding photovoltage of the input light. The individual nanoscale junctions are each generating up to ∼1.2 V of output voltage when illuminated in the infrared. We compare the optoelectronic properties of phototransducers prepared with designs having 5 to 12 junctions and that are exhibiting voltage outputs between >5 V and >14 V.
Stretching and folding in finite time
Authors: Ma Tian , Ouellette Nicholas T. , Bollt Erik M.
Published: February 2016

Complex flows mix efficiently, and this process can be understood by considering the stretching and folding of material volumes. Although many metrics have been devised to characterize stretching, fewer are able to capture folding in a quantitative way in spatiotemporally variable flows. Here, we extend our previous methods based on the finite-time curving of fluid-element trajectories to nonzero scales and show that this finite-scale finite-time curvature contains information about both stretching and folding. We compare this metric to the more commonly used finite-time Lyapunov exponent and illustrate our methods using experimental flow-field data from a quasi-two-dimensional laboratory flow. Our new analysis tools add to the growing set of Lagrangian methods for characterizing mixing in complex, aperiodic fluid flows.
Experimental study of vorticity-strain rate interaction in turbulent partially premixed jet flames using tomographic particle image velocimetry
Authors: Coriton Bruno , Frank Jonathan H.
Published: February 2016

In turbulent flows, the interaction between vorticity, ω, and strain rate, s, is considered a primary mechanism for the transfer of energy from large to small scales through vortex stretching. The ω-s coupling in turbulent jet flames is investigated using tomographic particle image velocimetry (TPIV). TPIV provides a direct measurement of the three-dimensional velocity field from which ω and s are determined. The effects of combustion and mean shear on the ω-s interaction are investigated in turbulent partially premixed methane/air jet flames with high and low probabilities of localized extinction as well as in a non-reacting isothermal air jet with Reynolds number of approximately 13 000. Results show that combustion causes structures of high vorticity and strain rate to agglomerate in highly correlated, elongated layers that span the height of the probe volume. In the non-reacting jet, these structures have a more varied morphology, greater fragmentation, and are not as well correlated. The enhanced spatiotemporal correlation of vorticity and strain rate in the stable flame results in stronger ω-s interaction characterized by increased enstrophy and strain-rate production rates via vortex stretching and straining, respectively. The probability of preferential local alignment between ω and the eigenvector of the intermediate principal strain rate, s2, which is intrinsic to the ω-s coupling in turbulent flows, is larger in the flames and increases with the flame stability. The larger mean shear in the flame imposes a preferential orientation of ω and s2 tangential to the shear layer. The extensive and compressive principal strain rates, s1 and s3, respectively, are preferentially oriented at approximately 45° with respect to the jet axis. The production rates of strain and vorticity tend to be dominated by instances in which ω is parallel to the s1¯-s2¯ plane and orthogonal to s3¯.
Internally contracted multireference coupled-cluster theory in a multistate framework
Authors: Aoto Yuri Alexandre , Köhn Andreas
Published: February 2016

The internally contracted multireference coupled cluster (icMRCC) theory is reexamined in a multistate framework. The new derivation starts from the Bloch equations employing a wave operator similar to the one originally employed by Jeziorski and Monkhorst [Phys. Rev. A 24, 1668 (1981)], but allows for a multideterminantal model-space basis. The resulting working equations are a generalization of state-universal multireference coupled-cluster (SU-MRCC) theory. In the case of truncated cluster operators, energies and wave functions depend on the choice of the model-space basis. It is shown that the state-specific solutions of the original icMRCC theory exactly diagonalize the effective Hamiltonian of the multistate theory and thus decouple the multistate equations. While this in principle means that icMRCC is a multistate theory, we find that truncated icMRCC theory still shows minor artifacts close to avoided crossings, which can be removed by considering a true multistate ansatz. The results also shed new light on the orbital variance of the original SU-MRCC theory.
Compact high-power microwave divider and combiner
Authors: Guo L. T. , Chang C. , Huang W. H. , Liu Y. S. , Cao Y. B. , Liu C. L. , Sun J.
Published: February 2016

A novel, compact, TM01-TE10 mode power divider and a novel, compact, four-way TE10-TM01 mode power combiner were theoretically designed and experimentally tested as a proof of principle. The theoretical and experimental S parameters are consistent with each other. High-power experiments show that their power capacities are no less than 1.5 GW and 3 GW, respectively. The devices have the merits of high power capacities and low insertion losses.
Production and characterization of a dual species magneto-optical trap of cesium and ytterbium
Authors: Kemp S. L. , Butler K. L. , Freytag R. , Hopkins S. A. , Hinds E. A. , Tarbutt M. R. , Cornish S. L.
Published: February 2016

We describe an apparatus designed to trap and cool a Yb and Cs mixture. The apparatus consists of a dual species effusive oven source, dual species Zeeman slower, magneto-optical traps in a single ultra-high vacuum science chamber, and the associated laser systems. The dual species Zeeman slower is used to load sequentially the two species into their respective traps. Its design is flexible and may be adapted for other experiments with different mixtures of atomic species. The apparatus provides excellent optical access and can apply large magnetic bias fields to the trapped atoms. The apparatus regularly produces 108 Cs atoms at 13.3 μK in an optical molasses, and 109 174Y b atoms cooled to 22 μK in a narrowband magneto-optical trap.
Temperature measurements during high flux ion beam irradiations
Authors: Crespillo M. L. , Graham J. T. , Zhang Y. , Weber W. J.
Published: February 2016

A systematic study of the ion beam heating effect was performed in a temperature range of −170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 1012 cm−2 s−1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. A simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beam analysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.
Free-standing gallium nitride membrane-based sensor for the impedimetric detection of alcohols
Authors: Alifragis Y. , Roussos G. , Pantazis A. K. , Konstantinidis G. , Chaniotakis N.
Published: February 2016

We report on the fabrication and characterization of single-crystal Gallium Nitride (GaN) membrane organic gas sensor. The sensing device is based on the highly stable free-standing III-nitride membrane, and it is probed using non-destructive impedance spectroscopy. Monitoring the effect of a series of polar organic molecules on the electrochemical impedance spectrum of the sensing membrane in the frequency range of 1 mHz to 0.1 MHz at room temperature, we concluded that the sensor is highly sensitive to alcohols, in the gas phase, with selectivity that depends on the molecular weight and vapor pressure of the molecules. The highly robust and stable GaN crystalline membrane and the ability to test these sensors using impedance spectroscopy and electrochemical probing techniques suggest that single crystal GaN-based sensors can find a wide range of applications in harsh and extreme environments.
The influence of fluoroalkyl chains in redox electrolytes for energy conversion
Authors: Jiang Qinglong , Yeh Yun-Peng , Lu Norman , Kuo Hung-Wei , Lesslie Michael , Xu Tao
Published: February 2016

We discovered an unprecedented fundamental interaction originated from the fluoroalkyl chains at the interface between light harvesting chromophore and charge transport redox electrolyte in dye-sensitized solar cells (DSSCs). A fluoroalkylated Ru complexes dye (FN719) was synthesized and upon anchoring on nanoparticulate TiO2 electrodes, FN719 exhibits 5 times better photostability in humid air than that of the conventional N719 due to the hydrophobicity of the fluoroalkyl chains. Moreover, the lipophobicity of fluoroalkylated chains in organic electrolyte causes a size-selective steric hindrance with respect to the redox couple I−/I3−, leading to a more stalled diffusion of the bulky I3− towards dyes and TiO2 photoanode than that of the lean I−. As such, without sacrificing the forward electron transport and quantum efficiency, the recombination in FN719-based DSSCs is suppressed to be 1.3 times slower than N719-based DSSCs studied by the photovoltage transients and electrochemical impedance spectroscopy; and the adverse I3− exchange with SCN− on dye is also inhibited as manifested by mass spectrometry. The J-V measurements suggest improved efficiency in FN719-based cells (9.2%) than similarly fabricated N719-based cells (8.5%).
High-gravity spreading of liquid puddles on wetting flexible substrates
Authors: Yang Chen , Burrous Adam , Xie Jingjin , Shaikh Hassan , Elike-Avion Akofa , Rojas Rodriguez Luis , Ramachandran Adithya , Choi Wonjae , Mazzeo Aaron D.
Published: February 2016

This letter describes a mechanical approach of using high gravity to decrease the capillary length and increase the spreading rate of liquid puddles on wetting flexible substrates. By using centrifugation and a flexible substrate floating on a high-density liquid, uniform acceleration enhances the spreading of liquid puddles. Under high gravity of 600 g, the capillary length reduces by a factor of 24.5 to ∼60 μm. The reduction in capillary length results in gravity dominating the spreading of small puddles that would otherwise have slower spreading driven by both surface tension and gravity of 1 g. The resulting measurements suggest that derived expressions in the literature for gravity-driven spreading of puddles under earth's standard gravity extend to predicting the behavior of sufficiently large puddles spreading on flexible substrates exposed to more than 100 g of acceleration. This work explores the spreading of puddles/coatings under high gravity, and the techniques described in this work will allow further interrogation of the transition between surface tension- and gravity-driven spreading.
The effect of interface roughness on exchange bias in La0.7Sr0.3MnO3–BiFeO3 heterostructures
Authors: Vafaee Mehran , Finizio Simone , Deniz Hakan , Hesse Dietrich , Zabel Hartmut , Jakob Gerhard , Kläui Mathias
Published: February 2016

We characterized the interfaces of heterostructures with different stack sequences of La0.7Sr0.3MnO3/BiFeO3 (LSMO/BFO) and BFO/LSMO using TEM revealing sharp and rough interfaces, respectively. Magnetometry and magnetoresistance measurements do not show a detectable exchange bias coupling for the multistack with sharp interface. Instead, the heterostructures with rough and chemically intermixed interfaces exhibit a sizable exchange bias coupling. Furthermore, we find a temperature-dependent irreversible magnetization behavior and an exponential decay of coercive and exchange bias fields with temperature suggesting a possible spin-glass-like state at the interface of both stacks.
Magnetic properties of bimetallic clusters composed of Gd and transition metals
Authors: Mukherjee Prajna , Gupta Bikash C. , Jena Puru
Published: February 2016

Gadolinium, a rare earth metal, is ferromagnetic, while Mn, a transition metal atom, is antiferromagnetic in the bulk phase. Clusters of these elements, however, share some common properties; both exhibit ferrimagnetic behavior and maintain magnetic moments close to their free atomic value. Using density functional theory and generalized gradient approximation for exchange and correlation, we have studied the magnetic properties of bimetallic clusters composed of Gd and Mn to see if they show unusual behavior. The coupling between Gd and Mn spins is found to be antiferromagnetic, while that between Mn atoms is ferromagnetic. Moreover, the bonding between Gd and Mn atoms is stronger than that between the Gd atoms or Mn atoms, thus enabling the possibility of creating more stable magnetic particles. A systematic study of the magnetic and binding properties of clusters composed of Gd atom and other transition metal atoms such as V, Sc, Ti, Cr, Fe, and Co is also carried out to probe the effect of 3d-orbital occupation on magnetic coupling.
Mixing of discontinuously deforming media
Authors: Smith L. D. , Rudman M. , Lester D. R. , Metcalfe G.
Published: February 2016

Mixing of materials is fundamental to many natural phenomena and engineering applications. The presence of discontinuous deformations—such as shear banding or wall slip—creates new mechanisms for mixing and transport beyond those predicted by classical dynamical systems theory. Here, we show how a novel mixing mechanism combining stretching with cutting and shuffling yields exponential mixing rates, quantified by a positive Lyapunov exponent, an impossibility for systems with cutting and shuffling alone or bounded systems with stretching alone, and demonstrate it in a fluid flow. While dynamical systems theory provides a framework for understanding mixing in smoothly deforming media, a theory of discontinuous mixing is yet to be fully developed. New methods are needed to systematize, explain, and extrapolate measurements on systems with discontinuous deformations. Here, we investigate “webs” of Lagrangian discontinuities and show that they provide a template for the overall transport dynamics. Considering slip deformations as the asymptotic limit of increasingly localised smooth shear, we also demonstrate exactly how some of the new structures introduced by discontinuous deformations are analogous to structures in smoothly deforming systems.
Resonance-enhanced waveguide-coupled silicon-germanium detector
Authors: Alloatti L. , Ram R. J.
Published: February 2016

A photodiode with 0.55 ± 0.1 A/W responsivity at a wavelength of 1176.9 nm has been fabricated in a 45 nm microelectronics silicon-on-insulator foundry process. The resonant waveguide photodetector exploits carrier generation in silicon-germanium within a microring which is compatible with high-performance electronics. A 3 dB bandwidth of 5 GHz at −4 V bias is obtained with a dark current of less than 20 pA.
Elastocaloric and barocaloric effects in polyvinylidene di-fluoride-based polymers
Authors: Patel Satyanarayan , Chauhan Aditya , Vaish Rahul , Thomas P.
Published: February 2016

Polyvinylidene di-fluoride-based polymers were investigated for elastocaloric and barocaloric effects. Bulk samples were subjected to uniaxial tensile and hydrostatic loading. Resulting strain profile (function of temperature) was used to predict the temperature change. A peak elastocaloric effect of 1.8 K was observed at 298 K (15 MPa). Alternately, a large barocaloric effect of ∼6 K was observed at 300 K (200 MPa). This was further improved to an astounding ∼19 K near 368 K (200 MPa). The results of this study are expected to greatly benefit the field of ferroelectric solid-state refrigeration and open another horizon for future exploration of multicaloric effects in ferroelectric polymers.
Anisotropic magnetoresistance dominant in a three terminal Hanle measurement
Authors: Malec Christopher , Miller Michael M. , Johnson Mark
Published: February 2016

Experiments are performed on mesoscopic nonlocal lateral spin valves with aluminum channels and Permalloy electrodes. Four-terminal magnetoresistance and Hanle measurements characterize the spin accumulation with results that compare well with published work. Three-terminal Hanle measurements of the Permalloy/aluminum (Py/Al) interfaces show bell-shaped curves that can be fit to Lorentzians. These curves are three orders of magnitude larger than the spin accumulation. Using anisotropic magnetoresistance measurements of individual Permalloy electrodes, we demonstrate that the three-terminal measurements are dominated by anisotropic magnetoresistance effects unrelated to spin accumulation.
Unaffectedness of improved wettability on critical heat flux enhancement with TiO2 sputtered surface
Authors: Maeng Yun Hwan , Song Sub Lee , Lee Jae Young
Published: February 2016

The improvement of surface wettability has been considered as a key factor of nanofluid critical heat flux (CHF) enhancement. However, the authors found that improved wettability did not influence on CHF at all. In this paper, the independent effect of surface wettability on CHF was experimentally investigated. The wettability of surface was controlled by DC plasma sputtering of TiO2 without any formation of porous structure. By controlling sputtering time of TiO2 from 12 s to 600 s, various contact angles were obtained from 62° to 11°. Compared to 82° of the bare surface, wettability was improved for all sputtered surface, but CHF was not changed meaningfully. The CHF data had no meaningful relationship at all with the variation of contact angle, so we concluded that wettability cannot be a main parameter of CHF and its enhancement.
Near-field control and imaging of free charge carrier variations in GaN nanowires
Authors: Berweger Samuel , Blanchard Paul T. , Brubaker Matt D. , Coakley Kevin J. , Sanford Norman A. , Wallis Thomas M. , Bertness Kris A. , Kabos Pavel
Published: February 2016

Despite their uniform crystallinity, the shape and faceting of semiconducting nanowires (NWs) can give rise to variations in structure and associated electronic properties. Here, we develop a hybrid scanning probe-based methodology to investigate local variations in electronic structure across individual n-doped GaN NWs integrated into a transistor device. We perform scanning microwave microscopy (SMM), which we combine with scanning gate microscopy to determine the free-carrier SMM signal contribution and image local charge carrier density variations. In particular, we find significant variations in free carriers across NWs, with a higher carrier density at the wire facets. By increasing the local carrier density through tip-gating, we find that the tip injects current into the NW with strongly localized current when positioned over the wire vertices. These results suggest that the strong variations in electronic properties observed within NWs have significant implications for device design and may lead to new paths to optimization.
Strain-induced red-green-blue wavelength tuning in InGaN quantum wells
Authors: Teng Chu-Hsiang , Zhang Lei , Deng Hui , Ku Pei-Cheng
Published: February 2016

Monolithically integrating multi-color pixels from a standard InGaN quantum well active region was demonstrated with a wavelength tuning range of 178 nm. Nanopillar structures were fabricated to enable the wavelength tuning. Strain induced wavelength shift was investigated both experimentally and theoretically. A simple one-dimensional strain relaxation model was shown to accurately predict the wavelength shift as a function of the nanopillar diameter. The strain relaxation was found to depend on the indium composition in the quantum well. No noticeable increase of the defect density was observed after the strain relaxation process.
Isomer-specific vibronic structure of the 9-, 1-, and 2-anthracenyl radicals via slow photoelectron velocity-map imaging
Authors: Weichman Marissa L. , DeVine Jessalyn A. , Levine Daniel S. , Kim Jongjin B. , Neumark Daniel M.
Published: February 2016

Significance

Polycyclic aromatic hydrocarbons (PAHs) are involved in soot nucleation following inefficient fuel combustion and are considered mutagens and environmental pollutants. They are also suspected to exist in the interstellar medium, although mechanisms for their formation in space are speculative. It is of great interest in these diverse fields to better characterize PAHs, including their dehydrogenated and charged derivatives, which are harder to isolate and probe. We use high-resolution anion photoelectron spectroscopy and quantum chemistry calculations to study the energetics, electronic states, and vibrational frequencies of the three dehydrogenated radical isomers of anthracene. These results provide signatures of these species for potential identification in space and illuminate subtle isomer-specific properties relevant to modeling their behavior in combustion and interstellar environments.
Crystal structure and stability of gyrase–fluoroquinolone cleaved complexes from
Mycobacterium tuberculosis
Authors: Blower Tim R. , Williamson Benjamin H. , Kerns Robert J. , Berger James M.
Published: February 2016

Significance

Although tuberculosis is a curable disease, its etiological agent,
Mycobacterium tuberculosis
(
Mtb
), remains a major human pathogen. Control of
Mtb
is hindered by multidrug-resistant strains, which can be currently treated with second-line agents that include fluoroquinolones such as moxifloxacin. Unfortunately, fluoroquinolone resistance is increasing, making improvements to quinolone efficacy clinically important. Fluoroquinolones act by forming complexes that poison
Mtb
. To our knowledge, this study describes the first X-ray crystal structures of the
Mtb
gyrase cleavage core complexed with DNA and five fluoroquinolones. These comparative structures inform efforts to design new quinolone-class agents and establish that the low intrinsic susceptibility of
Mtb
to clinically used fluoroquinolones is due to a paucity of specific gyrase–drug interactions.
RNase H2 catalytic core Aicardi-Goutières syndrome–related mutant invokes cGAS–STING innate immune-sensing pathway in mice
Authors: Pokatayev Vladislav , Hasin Naushaba , Chon Hyongi , Cerritelli Susana M. , Sakhuja Kiran , Ward Jerrold M. , Morris H. Douglas , Yan Nan , Crouch Robert J.
Published: February 2016

The neuroinflammatory autoimmune disease Aicardi-Goutières syndrome (AGS) develops from mutations in genes encoding several nucleotide-processing proteins, including RNase H2. Defective RNase H2 may induce accumulation of self-nucleic acid species that trigger chronic type I interferon and inflammatory responses, leading to AGS pathology. We created a knock-in mouse model with an RNase H2 AGS mutation in a highly conserved residue of the catalytic subunit, Rnaseh2aG37S/G37S (G37S), to understand disease pathology. G37S homozygotes are perinatal lethal, in contrast to the early embryonic lethality previously reported for Rnaseh2b- or Rnaseh2c-null mice. Importantly, we found that the G37S mutation led to increased expression of interferon-stimulated genes dependent on the cGAS–STING signaling pathway. Ablation of STING in the G37S mice results in partial rescue of the perinatal lethality, with viable mice exhibiting white spotting on their ventral surface. We believe that the G37S knock-in mouse provides an excellent animal model for studying RNASEH2-associated autoimmune diseases.
Reverberation of excitation in neuronal networks interconnected through voltage-gated gap junction channels
Authors: Maciunas Kestutis , Snipas Mindaugas , Paulauskas Nerijus , Bukauskas Feliksas F.
Published: February 2016

We combined Hodgkin–Huxley equations and gating models of gap junction (GJ) channels to simulate the spread of excitation in two-dimensional networks composed of neurons interconnected by voltage-gated GJs. Each GJ channel contains two fast and slow gates, each exhibiting current–voltage (I-V) rectification and gating properties that depend on transjunctional voltage (Vj). The data obtained show how junctional conductance (gj), which is necessary for synchronization of the neuronal network, depends on its size and the intrinsic firing rate of neurons. A phase shift between action potentials (APs) of neighboring neurons creates bipolar, short-lasting Vj spikes of approximately ±100 mV that induce Vj gating, leading to a small decay of gj, which can accumulate into larger decays during bursting activity of neurons. We show that I-V rectification of GJs in local regions of the two-dimensional network of neurons can lead to unidirectional AP transfer and consequently to reverberation of excitation. This reverberation can be initiated by a single electrical pulse and terminated by a low-amplitude pulse applied in a specific window of reverberation cycle. Thus, the model accounts for the influence of dynamically modulatable electrical synapses in shaping the function of a neuronal network and the formation of reverberation, which, as proposed earlier, may be important for the development of short-term memory and its consolidation into long-term memory.