bluuebunny/crossref_metadata_2025 huggingface dataset:
Membrane lipidomics in schizophrenia patients: a correlational study with clinical and cognitive manifestations
Authors: Tessier C , Sweers K , Frajerman A , Bergaoui H , Ferreri F , Delva C , Lapidus N , Lamaziere A , Roiser J P , De Hert M , Nuss P
Published: October 2016

Schizophrenia is a severe mental condition in which several lipid abnormalities—either structural or metabolic—have been described. We tested the hypothesis that an abnormality in membrane lipid composition may contribute to aberrant dopamine signaling, and thereby symptoms and cognitive impairment, in schizophrenia (SCZ) patients. Antipsychotic-medicated and clinically stable SCZ outpatients (n=74) were compared with matched healthy subjects (HC, n=40). A lipidomic analysis was performed in red blood cell (RBC) membranes examining the major phospholipid (PL) classes and their associated fatty acids (FAs). Clinical manifestations were examined using the positive and negative syndrome scale (PANSS). Cognitive function was assessed using the Continuous Performance Test, Salience Attribution Test and Wisconsin Card Sorting Test. Sphingomyelin (SM) percentage was the lipid abnormality most robustly associated with a schizophrenia diagnosis. Two groups of patients were defined. The first group (SCZ c/SM−) is characterized by a low SM membrane content. In this group, all other PL classes, plasmalogen and key polyunsaturated FAs known to be involved in brain function, were significantly modified, identifying a very specific membrane lipid cluster. The second patient group (SCZ c/SM+) was similar to HCs in terms of RBC membrane SM composition. Compared with SCZ c/SM+, SCZ c/SM− patients were characterized by significantly more severe PANSS total, positive, disorganized/cognitive and excited psychopathology. Cognitive performance was also significantly poorer in this subgroup. These data show that a specific RBC membrane lipid cluster is associated with clinical and cognitive manifestations of dopamine dysfunction in schizophrenia patients. We speculate that this membrane lipid abnormality influences presynaptic dopamine signaling.
RGS2 expression predicts amyloid-β sensitivity, MCI and Alzheimer’s disease: genome-wide transcriptomic profiling and bioinformatics data mining
Authors: Hadar A , Milanesi E , Squassina A , Niola P , Chillotti C , Pasmanik-Chor M , Yaron O , Martásek P , Rehavi M , Weissglas-Volkov D , Shomron N , Gozes I , Gurwitz D
Published: October 2016

Alzheimer's disease (AD) is the most frequent cause of dementia. Misfolded protein pathological hallmarks of AD are brain deposits of amyloid-β (Aβ) plaques and phosphorylated tau neurofibrillary tangles. However, doubts about the role of Aβ in AD pathology have been raised as Aβ is a common component of extracellular brain deposits found, also by in vivo imaging, in non-demented aged individuals. It has been suggested that some individuals are more prone to Aβ neurotoxicity and hence more likely to develop AD when aging brains start accumulating Aβ plaques. Here, we applied genome-wide transcriptomic profiling of lymphoblastoid cells lines (LCLs) from healthy individuals and AD patients for identifying genes that predict sensitivity to Aβ. Real-time PCR validation identified 3.78-fold lower expression of RGS2 (regulator of G-protein signaling 2; P=0.0085) in LCLs from healthy individuals exhibiting high vs low Aβ sensitivity. Furthermore, RGS2 showed 3.3-fold lower expression (P=0.0008) in AD LCLs compared with controls. Notably, RGS2 expression in AD LCLs correlated with the patients’ cognitive function. Lower RGS2 expression levels were also discovered in published expression data sets from postmortem AD brain tissues as well as in mild cognitive impairment and AD blood samples compared with controls. In conclusion, Aβ sensitivity phenotyping followed by transcriptomic profiling and published patient data mining identified reduced peripheral and brain expression levels of RGS2, a key regulator of G-protein-coupled receptor signaling and neuronal plasticity. RGS2 is suggested as a novel AD biomarker (alongside other genes) toward early AD detection and future disease modifying therapeutics.
Electrodeposition of Thermoelectric Materials
Authors: Naylor A. J. , White N. M. , Nandhakumar I.
Published: October 2016

Electrodeposition can be used as a cost-effective, room temperature technique for the fabrication of thermoelectric materials, as opposed to more traditional methods, such as chemical vapour deposition or molecular beam epitaxy, that require high temperatures and vacuum conditions. This chapter deals with understanding how electrodeposition can be applied as a technique, reviewing recent developments in its use in the deposition of thermoelectric materials, and exploring the use of additives and dopants during the deposition process in order to enhance the thermoelectric properties of the material. Results are presented to show how a surfactant, sodium lignosulfonate, can be added to an electrolyte in order to produce levelled and compact Bi2Te3 thin films with a preferred crystallographic orientation, thought to offer improved thermoelectric efficiency. Doping of ternary bismuth tellurium selenide semiconductor n-type thermoelectric deposits with small fractions of copper can be used to achieve a reduced crystallite size and dramatic enhancements in thermoelectric performance.
A review: the trend of progress about pH probes in cell application in recent years
Authors: Yue Yongkang , Huo Fangjun , Lee Songyi , Yin Caixia , Yoon Juyoung
Published: October 2016

Intracellular pH values are some of the most important factors that govern biological processes and the acid–base homeostasis in cells, body fluids and organs sustains the normal operations of the body.
Selective electrochemiluminescent sensing of saccharides using boronic acid-modified coreactant
Authors: Li Haidong , Sedgwick Adam C. , Li Meng , Blackburn Richard A. R. , Bull Steven D. , Arbault Stéphane , James Tony D. , Sojic Neso
Published: October 2016

We report a strategy for modulating the electrogenerated chemiluminescence (ECL) response by integrating a boronic acid to the chemical structure of coreactants.
Catalytic aspects of metallophthalocyanines adsorbed on gold-electrode. Theoretical exploration of the binding nature role
Authors: Miranda-Rojas Sebastián , Sierra-Rosales Paulina , Muñoz-Castro Alvaro , Arratia-Pérez Ramiro , Zagal José Heráclito , Mendizábal Fernando
Published: October 2016

We report a computational study of supramolecular complexes of metallophthalocyanines (MPcs, M = Fe, Co, Cu) on gold substrates, and the effect of the substrate on their electrocatalytic properties at the DFT and DFT-D3 levels.
Solid-state study of the structure and host–guest chemistry of cucurbituril-ferrocene inclusion complexes
Authors: Gomes Ana C. , Magalhães Clara I. R. , Oliveira Tânia S. M. , Lopes André D. , Gonçalves Isabel S. , Pillinger Martyn
Published: October 2016

Solid-state host–guest interactions have been investigated for cucurbit[n]uril-ferrocene inclusion compounds (n = 7, 8) prepared via a microwave-assisted hydrothermal approach.
Alkyl Grignard cross-coupling of aryl phosphates catalyzed by new, highly active ionic iron(ii) complexes containing a phosphine ligand and an imidazolium cation
Authors: Li Zhuang , Liu Ling , Sun Hong-mei , Shen Qi , Zhang Yong
Published: October 2016

Ionic iron(ii) complexes, [HL][Fe(PR3)X3], showed high catalytic activities in alkyl Grignard cross-coupling of aryl phosphates, and the corresponding reductive cross-coupling.
Assessment of the nematocidal activity of metallocenyl analogues of monepantel
Authors: Hess Jeannine , Patra Malay , Jabbar Abdul , Pierroz Vanessa , Konatschnig Sandro , Spingler Bernhard , Ferrari Stefano , Gasser Robin B. , Gasser Gilles
Published: October 2016

Ferrocenyl and ruthenocenyl analogues of the nematocidal drug monepantel show organometallic-dependent activity against Haemonchus contortus and Trichostrongylus colubriformis.
Enzymatic photosynthesis of formate from carbon dioxide coupled with highly efficient photoelectrochemical regeneration of nicotinamide cofactors
Authors: Nam Dong Heon , Kuk Su Keun , Choe Hyunjun , Lee Sumi , Ko Jong Wan , Son Eun Jin , Choi Eun-Gyu , Kim Yong Hwan , Park Chan Beum
Published: October 2016

We present the photoelectrochemical (PEC) regeneration of nicotinamide cofactors (NADH) coupled with the enzymatic synthesis of formate from CO2 towards mimicking natural photosynthesis.
Solvent from forestry biomass. Pinane a stable terpene derived from pine tree byproducts to substitute n-hexane for the extraction of bioactive compounds
Authors: Yara-Varón E. , Selka A. , Fabiano-Tixier A. S. , Balcells M. , Canela-Garayoa R. , Bily Antoine , Touaibia M. , Chemat F.
Published: October 2016

Pinane, obtained by catalytic hydrogenation of α/β-pinenes or turpentine oil, was used as an alternative solvent for the extraction of several bioactive compounds.
“Host–guest” binding of a luminescent dinuclear Au(i) complex based on cyclic diphosphine with organic substrates as a reason for luminescence tuneability
Authors: Shamsutdinova Nataliya A. , Strelnik Igor D. , Musina Elvira I. , Gerasimova Tatyana P. , Katsyuba Sergey A. , Babaev Vasily M. , Krivolapov Dmitry B. , Litvinov Igor A. , Mustafina Asiya R. , Karasik Andrey A. , Sinyashin Oleg G.
Published: October 2016

A dinuclear Au(i) complex with cyclic diphosphine is a versatile platform for different luminescence responses to nucleophilic and electrophilic molecules in solutions.
Dual donor–π–acceptor type organic dyes for efficient dye-sensitized solar cells
Authors: Chang Pei-Yu , Wang Po-Hsin , Lin Wen-Churng , Yang Chien-Hsin
Published: October 2016

A dual-styrene-π-linked triphenylamine dye was synthesized, showing effective improvement in the efficiency of the corresponding devices as compared to no π-linker dyes.
Design, synthesis, and biological evaluation of CXCR4 ligands
Authors: Mona Christine E. , Besserer-Offroy Élie , Cabana Jérôme , Leduc Richard , Lavigne Pierre , Heveker Nikolaus , Marsault Éric , Escher Emanuel
Published: October 2016

An amino functionalized analog of the CXCR4 ligand IT1t is of higher affinity and inverse agonistic potency on the CXCR4-CAM receptor N119S than IT1t.
2-Aryl-indenylphosphine ligands: design, synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions
Authors: Lian Ze-Yu , Yuan Jia , Yan Meng-Qi , Liu Yan , Luo Xue , Wu Qing-Guo , Liu Sheng-Hua , Chen Jian , Zhu Xiao-Lei , Yu Guang-Ao
Published: October 2016

A focused library of phosphine ligands was constructed for structural optimization. The catalyst can be used to perform the Suzuki–Miyaura cross-coupling reaction of aryl and heteroaryl chlorides.
Highly enantioselective asymmetric Henry reaction catalyzed by novel chiral phase transfer catalysts derived from cinchona alkaloids
Authors: Vijaya Ponmuthu Kottala , Murugesan Sepperumal , Siva Ayyanar
Published: October 2016

Newly synthesized CPTCs are applied in the asymmetric Henry reaction to a wide range of aldehydes under mild reaction conditions, and we obtained higher chemical yields and an excellent enantiomeric excess.
Identification of small molecule inhibitors of the Lin28-mediated blockage of pre-let-7g processing
Authors: Lightfoot Helen L. , Miska Eric A. , Balasubramanian Shankar
Published: October 2016

Small molecules enhance Dicer processing of a let-7 miRNA precursor through antagonization of the Lin28–pre-let-7 interaction.
Diastereoselective sp2–sp3 coupling of sugar enol ethers with unactivated cycloalkenes: new entries to C-branched sugars
Authors: Hussain Nazar , Tatina Madhu Babu , Rasool Faheem , Mukherjee Debaraj
Published: October 2016

Sugar enol ethers undergo efficient coupling at C-2 with unactivated cycloalkenes under a low Pd loading affording allylic substitution products. High diastereoselectivity was observed at the allylic centre with sterically hindered substrates.
An aggregation-induced emission star polymer with pH and metal ion responsive fluorescence
Authors: Zhao Yuming , Zhu Wen , Wu Ying , Qu Lin , Liu Zhengping , Zhang Ke
Published: October 2016

A one-pot strategy from ring-opening metathesis polymerization was employed to prepare AIE-active star polymers, which were designed to have multi-responsive fluorescence to varied stimuli including pH, CO2, and metal ions.
Electrospun H4SiW12O40/chitosan/polycaprolactam sandwich nanofibrous membrane with excellent dual-function: adsorption and photocatalysis
Authors: Cui Xiangxu , Li Tingting , Yao Shaowei , An Libao , Li Yuqing , Zhou Zhi , Guo Mengchao , Zhang Zhiming
Published: October 2016

Scheme of the structure of the SNM, the treatment of Cr(vi) and MO in aqueous solutions, and the regeneration process.
Solvent-induced improvement of Au photo-deposition and resulting photo-catalytic efficiency of Au/TiO2
Authors: Kenens Bart , Chamtouri Maha , Aubert Remko , Miyakawa Kana , Hayasaka Yasufumi , Naiki Hiroyuki , Watanabe Hiroki , Inose Tomoko , Fujita Yasuhiko , Lu Gang , Masuhara Akito , Uji-i Hiroshi
Published: October 2016

Metal nanoparticle photo-deposition on TiO2enhances the semiconductor catalytic activity.
PMDETA as an efficient catalyst for bulk reversible complexation mediated polymerization (RCMP) in the absence of additional metal salts and deoxygenation
Authors: Wang Wenxiang , Bai Liangjiu , Chen Hou , Xu Hui , Niu Yuzhong , Tao Qian , Cheng Zhenping
Published: October 2016

PMDETA was used as a commercial and efficient catalyst for reversible complexation mediated polymerization (RCMP) without deoxygenation in bulk, which could potentially allow the more facile preparation, post-treatment and storage.
Tuning surface accessibility and catalytic activity of Au nanoparticles through immobilization within porous-organic polymers
Authors: Haikal Rana R. , Elmansi Ahmed M. , Soliman Ahmed B. , Aly Poussy , Hassan Youssef S. , Berber Mohamed R. , Hafez Inas H. , Hassanien Abdou , Alkordi Mohamed H.
Published: October 2016

A facile approach to immobilize Au nanoparticles within porous-organic polymers is reported, resulting in controlled access and reactivity of the Au nanoparticles.
Allylation of a lignin model phenol: a highly selective reaction under benign conditions towards a new thermoset resin platform
Authors: Jawerth M. , Lawoko M. , Lundmark S. , Perez-Berumen C. , Johansson M.
Published: October 2016

Highly selective functionalization of a lignin model compound to form thermoset resins under benign conditions.
Accelerated ceria–zirconia solubilization by cationic diffusion inversion at low oxygen activity
Authors: Esposito Vincenzo , Ni De Wei , Marani Debora , Teocoli Francesca , Sune Thydén Karl Tor , De Florio Daniel Zanetti , Fonseca Fabio Coral
Published: October 2016

Fast elemental diffusion at the Gd-doped ceria/Y-stabilized zirconia interface occurs under reducing conditions at low oxygen activity and high temperatures.
Ni2P–CoP hybrid nanosheet arrays supported on carbon cloth as an efficient flexible cathode for hydrogen evolution
Authors: Wang An-Liang , Lin Jing , Xu Han , Tong Ye-Xiang , Li Gao-Ren
Published: October 2016

Here we report a new type of Ni2P–CoP hybrid nanosheet arrays (HNSAs) supported on carbon cloth (CC) (Ni2P–CoP HNSAs/CC) as an efficient flexible cathode for the hydrogen evolution reaction (HER).
Lipid droplets alleviate cadmium induced cytotoxicity in Saccharomyces cerevisiae
Authors: Rajakumar Selvaraj , Nachiappan Vasanthi
Published: October 2016

Cadmium (Cd) induces oxidative stress that generates reactive oxygen species (ROS) and increased lipid accumulation.
Gesture Use in 14-Month-Old Toddlers With Hearing Loss and Their Mothers' Responses
Authors: Ambrose Sophie E.
Published: October 2016

Purpose

This study examined the gesture use of 14-month-old toddlers with hearing loss (HL) and mothers' responses to children's early gesture use. Comparisons were made to symbolic language and to dyads in which the toddler had normal hearing (NH).

Method

Participants were 25 mother–toddler dyads in which the child had HL and a socioeconomic-status matched group of 23 mother–toddler dyads in which the child had NH. Thirty-minute mother–child interactions were video-recorded, transcribed for spoken language, sign, and gesture use, and coded for maternal responses to children's gestures. Mothers also reported on children's gestural and spoken language abilities.

Results

Toddlers with HL used gesture similarly to their peers with NH, but demonstrated delays in spoken language. Spoken language and gesture were not significantly related for either group. Hearing levels were related to spoken language, but not gesture for the HL group. Maternal and child gesture were only related for signing mothers. Mothers of children with HL were more likely than their counterparts to provide no response to children's gestures.

Conclusion

Although toddlers' gesture abilities remain intact in the presence of HL, mothers were not maximally responsive to those gestures and thus should be coached to increase their provision of contingent feedback.
The Home Literacy Environment and the English Narrative Development of Spanish–English Bilingual Children
Authors: Bitetti Dana , Hammer Carol Scheffner
Published: October 2016

Purpose

The purpose of this study was to examine the impact of the home literacy environment (HLE) on the English narrative development of Spanish–English bilingual children from low-income backgrounds.

Method

Longitudinal data were collected on 81 bilingual children from preschool through 1st grade. English narrative skills were assessed in the fall and spring of each year. Microstructure measures included mean length of utterance in morphemes and number of different words. The Narrative Scoring Scheme (Heilmann, Miller, Nockerts, & Dunaway, 2010) measured macrostructure. Each fall, the children's mothers reported the frequency of literacy activities and number of children's books in the home. Growth curve modeling was used to describe the children's narrative development and the impact of the HLE over time.

Results

Significant growth occurred for all narrative measures. The HLE did not affect microstructure growth. The frequency with which mothers read to their children had a positive impact on the growth of the children's total Narrative Scoring Scheme scores. Other aspects of the HLE, such as the frequency with which the mothers told stories, did not affect macrostructure development.

Conclusions

These results provide information about the development of English narrative abilities and demonstrate the importance of frequent book reading for the overall narrative quality of children from Spanish-speaking homes who are learning English.
Vorticity isotropy in high Karlovitz number premixed flames
Authors: Bobbitt Brock , Blanquart Guillaume
Published: October 2016

The isotropy of the smallest turbulent scales is investigated in premixed turbulent combustion by analyzing the vorticity vector in a series of high Karlovitz number premixed flame direct numerical simulations. It is found that increasing the Karlovitz number and the ratio of the integral length scale to the flame thickness both reduce the level of anisotropy. By analyzing the vorticity transport equation, it is determined that the vortex stretching term is primarily responsible for the development of any anisotropy. The local dynamics of the vortex stretching term and vorticity resemble that of homogeneous isotropic turbulence to a greater extent at higher Karlovitz numbers. This results in small scale isotropy at sufficiently high Karlovitz numbers and supports a fundamental similarity of the behavior of the smallest turbulent scales throughout the flame and in homogeneous isotropic turbulence. At lower Karlovitz numbers, the vortex stretching term and the vorticity alignment in the strain-rate tensor eigenframe are altered by the flame. The integral length scale has minimal impact on these local dynamics but promotes the effects of the flame to be equal in all directions. The resulting isotropy in vorticity does not reflect a fundamental similarity between the smallest turbulent scales in the flame and in homogeneous isotropic turbulence.
Molecular origins of higher harmonics in large-amplitude oscillatory shear flow: Shear stress response
Authors: Gilbert P. H. , Giacomin A. J.
Published: October 2016

Recent work has focused on deepening our understanding of the molecular origins of the higher harmonics that arise in the shear stress response of polymeric liquids in large-amplitude oscillatory shear flow. For instance, these higher harmonics have been explained by just considering the orientation distribution of rigid dumbbells suspended in a Newtonian solvent. These dumbbells, when in dilute suspension, form the simplest relevant molecular model of polymer viscoelasticity, and this model specifically neglects interactions between the polymer molecules [R. B. Bird et al., “Dilute rigid dumbbell suspensions in large-amplitude oscillatory shear flow: Shear stress response,” J. Chem. Phys. 140, 074904 (2014)]. In this paper, we explore these interactions by examining the Curtiss-Bird model, a kinetic molecular theory designed specifically to account for the restricted motions that arise when polymer chains are concentrated, thus interacting and specifically, entangled. We begin our comparison using a heretofore ignored explicit analytical solution [X.-J. Fan and R. B. Bird, “A kinetic theory for polymer melts. VI. Calculation of additional material functions,” J. Non-Newtonian Fluid Mech. 15, 341 (1984)]. For concentrated systems, the chain motion transverse to the chain axis is more restricted than along the axis. This anisotropy is described by the link tension coefficient, ϵ, for which several special cases arise: ϵ = 0 corresponds to reptation, ϵ > 1/8 to rod-climbing, 1/5 ≤ ϵ ≤ 3/4 to reasonable predictions for shear-thinning in steady simple shear flow, and ϵ = 1 to the dilute solution without hydrodynamic interaction. In this paper, we examine the shapes of the shear stress versus shear rate loops for the special cases ϵ=0,1/8,3/8,1, and we compare these with those of rigid dumbbell and reptation model predictions.
Orientational distribution functions and order parameters in “de Vries”-type smectics: A simulation study
Authors: Jenz Frank , Osipov Mikhail A. , Jagiella Stefan , Giesselmann Frank
Published: October 2016

Simple smectic A liquid crystal phases with different types of prescribed orientational distribution functions have been simulated and compared in order to study the possibility to distinguish between the Maier-Saupe type and cone-like orientational distributions using the popular method of Davidson et al. [J. Phys. II 5, 113 (1995)]. This method has been used to extract the orientational distribution functions from simulated diffraction patterns, and the results have been compared with actual distribution functions which have been prescribed during simulations. It has been shown that it is indeed possible to distinguish between these two qualitatively different types of orientational distribution already from the shape of the 2D diffraction pattern. Moreover, typical experimental diffraction patterns for “de Vries”-type smectic liquid crystals appear to be close to the ones which have been simulated using the prescribed Maier-Saupe orientational distribution function.
Sliding-mode control of single input multiple output DC-DC converter
Authors: Zhang Libo , Sun Yihan , Luo Tiejian , Wan Qiyang
Published: October 2016

Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.
Extending helium partial pressure measurement technology to JET DTE2 and ITER
Authors: Klepper C. C. , Biewer T. M. , Kruezi U. , Vartanian S. , Douai D. , Hillis D. L. , Marcus C. ,   JET Contributors
Published: October 2016

The detection limit for helium (He) partial pressure monitoring via the Penning discharge optical emission diagnostic, mainly used for tokamak divertor effluent gas analysis, is shown here to be possible for He concentrations down to 0.1% in predominantly deuterium effluents. This result from a dedicated laboratory study means that the technique can now be extended to intrinsically (non-injected) He produced as fusion reaction ash in deuterium-tritium experiments. The paper also examines threshold ionization mass spectroscopy as a potential backup to the optical technique, but finds that further development is needed to attain with plasma pulse-relevant response times. Both these studies are presented in the context of continuing development of plasma pulse-resolving, residual gas analysis for the upcoming JET deuterium-tritium campaign (DTE2) and for ITER.
Mesoscopic current transport in two-dimensional materials with grain boundaries: Four-point probe resistance and Hall effect
Authors: Lotz Mikkel R. , Boll Mads , Østerberg Frederik W. , Hansen Ole , Petersen Dirch H.
Published: October 2016

We have studied the behavior of micro four-point probe (M4PP) measurements on two-dimensional (2D) sheets composed of grains of varying size and grain boundary resistivity by Monte Carlo based finite element (FE) modelling. The 2D sheet of the FE model was constructed using Voronoi tessellation to emulate a polycrystalline sheet, and a square sample was cut from the tessellated surface. Four-point resistances and Hall effect signals were calculated for a probe placed in the center of the square sample as a function of grain density n and grain boundary resistivity ρGB. We find that the dual configuration sheet resistance as well as the resistance measured between opposing edges of the square sample have a simple unique dependency on the dimension-less parameter nρGBG0, where G0 is the sheet conductance of a grain. The value of the ratio RA/RB between resistances measured in A- and B-configurations depends on the dimensionality of the current transport (i.e., one- or two-dimensional). At low grain density or low grain boundary resistivity, two-dimensional transport is observed. In contrast, at moderate grain density and high grain resistivity, one-dimensional transport is seen. Ultimately, this affects how measurements on defective systems should be interpreted in order to extract relevant sample parameters. The Hall effect response in all M4PP configurations was only significant for moderate grain densities and fairly large grain boundary resistivity.
Explicitly correlated coupled-cluster theory for static polarizabilities
Authors: Bokhan Denis , Trubnikov Dmitrii N. , Perera Ajith , Bartlett Rodney J.
Published: October 2016

A method of calculation of static polarizabilities with wavefunctions, corresponding to linearly approximated explicitly correlated coupled-cluster singles and doubles [CCSD(F12)] model, has been formulated and implemented. For the proper description of the response of system on applied electric field, modified ansatz is introduced for geminal part of cluster operators. Such extension of CCSD(F12) model provides balanced description of both perturbed and unperturbed wave functions, what leads to the increase of the accuracy of target polarizabilities. As a part of algorithm, explicitly correlated version of coupled-perturbed CCSD equations has also been derived and implemented. Numerical tests conducted for the set of eight molecules show good agreement between static polarizabilities, calculated with developed explicitly correlated approach and corresponding complete basis set results in regular CCSD already at triple-ζ level.
Unphysical divergences in response theory
Authors: Parker Shane M. , Roy Saswata , Furche Filipp
Published: October 2016

Transition densities between excited states are key for nonlinear theoretical spectroscopy and multi-state non-adiabatic molecular dynamics (NAMD) simulations. In the framework of response theory, these transition densities are accessible from poles of the quadratic response function. It was shown recently that the thus obtained transition densities within time-dependent Hartree-Fock (TDHF) and adiabatic time-dependent density functional theory (TDDFT) exhibit unphysical divergences when the difference in excitation energy of the two states of interest matches another excitation energy. This unphysical behavior is a consequence of spurious poles in the quadratic response function. We show that the incorrect pole structure of the quadratic response is not limited to TDHF and adiabatic TDDFT, but is also present in many other approximate many-electron response functions, including those from coupled cluster and multiconfigurational self-consistent field response theory. The divergences appear in regions of the potential energy surface where the ground state is perfectly well behaved, and they are frequently encountered in NAMD simulations of photochemical reactions. The origin of the divergences is traced to an incorrect instantaneous time-dependence of the effective Hamiltonian. The implications for computations of frequency-dependent response properties are considerable and call into question the validity of conventional approximate many-electron response theories beyond linear response.
Magnetostrictive iron gallium thin films grown onto antiferromagnetic manganese nitride: Structure and magnetism
Authors: Mandru Andrada-Oana , Corbett Joseph P. , Richard Andrea L. , Gallagher James , Meng Keng-Yuan , Ingram David C. , Yang Fengyuan , Smith Arthur R.
Published: October 2016

We report structural and magnetic properties of magnetostrictive Fe100−xGax (x ≈ 15) alloys when deposited onto antiferromagnetic manganese nitride and non-magnetic magnesium oxide substrates. From X-ray diffraction measurements, we find that the FeGa films are single crystalline. Scanning tunneling microscopy imaging reveals that the surface morphologies are dictated by the growth temperature, composition, and substrate. The magnetic properties can be tailored by the substrate, as found by magnetic force microscopy imaging and vibrating sample magnetometry measurements. In addition to pronounced tetragonal deformations, depositing FeGa onto manganese nitride leads to the formation of stripe-like magnetic domain patterns and to the appearance of perpendicular magnetic anisotropy.
Column-by-column observation of dislocation motion in CdTe: Dynamic scanning transmission electron microscopy
Authors: Li Chen , Zhang Yu-Yang , Pennycook Timothy J. , Wu Yelong , Lupini Andrew R. , Paudel Naba , Pantelides Sokrates T. , Yan Yanfa , Pennycook Stephen J.
Published: October 2016

The dynamics of partial dislocations in CdTe have been observed at the atomic scale using aberration-corrected scanning transmission electron microscopy (STEM), allowing the mobility of different dislocations to be directly compared: Cd-core Shockley partial dislocations are more mobile than Te-core partials, and dislocation cores with unpaired columns have higher mobility than those without unpaired columns. The dynamic imaging also provides insight into the process by which the dislocations glide. Dislocations with dangling bonds on unpaired columns are found to be more mobile because the dangling bonds mediate the bond exchanges required for the dislocations to move. Furthermore, a screw dislocation has been resolved to dissociate into a Shockley partial-dislocation pair along two different directions, revealing a way for the screw dislocation to glide in the material. The results show that dynamic STEM imaging has the potential to uncover the details of dislocation motion not easily accessible by other means.
Low-cost chemiresistive sensor for volatile amines based on a 2D network of a zinc(II) Schiff-base complex
Authors: Mirabella S. , Oliveri I. P. , Ruffino F. , Maccarrone G. , Di Bella S.
Published: October 2016

A marked chemiresistive behavior is revealed in a nanostructured material obtained by spin-coating a solution of a bis(salycilaldiminato)Zn(II) Schiff-base (ZnSB) complex. The resulting submicron 2D network exhibits reversible changes in absorbance and resistance under the cycles of absorption and desorption of a volatile amine. These results are explained in terms of a Lewis donor-acceptor interaction between the ZnSB (acceptor) and the chemisorbed amine (donor). The 2D network of ZnSB was employed as a sensing element to fabricate a low-cost device for the volatile amines detection, showing promising results for food spoilage detection.
Design and modeling of magnetically driven electric-field sensor for non-contact DC voltage measurement in electric power systems
Authors: Wang Decai , Li Ping , Wen Yumei
Published: October 2016

In this paper, the design and modeling of a magnetically driven electric-field sensor for non-contact DC voltage measurement are presented. The magnetic drive structure of the sensor is composed of a small solenoid and a cantilever beam with a cylindrical magnet mounted on it. The interaction of the magnet and the solenoid provides the magnetic driving force for the sensor. Employing magnetic drive structure brings the benefits of low driving voltage and large vibrating displacement, which consequently results in less interference from the drive signal. In the theoretical analyses, the capacitance calculation model between the wire and the sensing electrode is built. The expression of the magnetic driving force is derived by the method of linear fitting. The dynamical model of the magnetic-driven cantilever beam actuator is built by using Euler-Bernoulli theory and distributed parameter method. Taking advantage of the theoretical model, the output voltage of proposed sensor can be predicted. The experimental results are in good agreement with the theoretical results. The proposed sensor shows a favorable linear response characteristic. The proposed sensor has a measuring sensitivity of 9.87 μV/(V/m) at an excitation current of 37.5 mA. The electric field intensity resolution can reach 10.13 V/m.
Recoupling the singlet- and triplet-pairing channels in single-reference coupled cluster theory
Authors: Gomez John A. , Henderson Thomas M. , Scuseria Gustavo E.
Published: October 2016

It is well known that single-reference coupled cluster theory truncated to low orders of excitations gives the right answer for the right reason when systems are dominated by dynamical or weak correlation. Static or strong correlation is more problematic, causing often catastrophic breakdown of restricted coupled cluster. This failure can be remedied, e.g., by allowing symmetry breaking in the reference or taking a multi-reference approach, but poses an interesting theoretical problem, especially since many groups have found that simplifying the T2 operator or the doubles amplitude equations gives better results. In singlet-paired coupled cluster, eliminating the triplet-pairing channel recovers reasonable qualitative behavior for strong correlation at the cost of a decreased description of dynamical correlation in weakly correlated situations. This behavior seems to hold for both closed- and open-shell systems. In this work, we explore the coupling of the singlet- and triplet-pairing channels of T2 and attempt to recouple them in order to recover dynamical correlation without reintroducing catastrophic failure due to strong correlation. In the weakly correlated regime, these pairing channels are only weakly coupled, and a simple recoupling gives good results. However, as strong correlation dominates, the coupling strength between the singlet- and triplet-pairing channels increases, making it difficult to perturbatively recouple the singlet- and triplet-pairing channels in this regime.
Resonant tunneling of carriers in silicon nanocrystals
Authors: Derbenyova N. V. , Konakov A. A. , Burdov V. A.
Published: October 2016

The rates of resonant and nearly resonant tunnel transitions have been calculated within the envelope function approximation for electrons and holes in silicon nanocrystals embedded in a silicon dioxide matrix. It is shown that, if the nanocrystals are close enough, the rates of resonant tunneling reach the values of the order of 1012–1014 s−1, which considerably exceed the rates of radiative recombination and other basic non-radiative processes, such as the Auger recombination and capture on surface defects. The transition rate is found to be very sensitive to inter-crystallite distance, crystallite size, and effective mass of the carriers in the oxide matrix. Electron tunneling turns out to be faster than the hole one, especially, at greater distances between the nanocrystals. Thus, the tunnel migration in a dense ensemble of nanocrystals is mainly electronic.
Coupling of the electrocaloric and electromechanical effects for solid-state refrigeration
Authors: Bradeško A. , Juričić Đ. , Santo Zarnik M. , Malič B. , Kutnjak Z. , Rojac T.
Published: October 2016

Electrocaloric (EC) materials have shown the potential to replace some of the technologies in current commercial refrigeration systems. The key problem when fabricating an efficient EC refrigerator is the small adiabatic temperature change that current bulk materials can achieve. Therefore, such a solid-state EC refrigerator should be engineered to enhance the EC temperature change by rectifying the induced EC heat flow. Here, we present a numerical study of a device that couples the EC and electromechanical (EM) effects in a single active material. The device consists of several elements made from a functional material with coupled EC and EM properties, allowing the elements to bend and change their temperature with the application of an electric field. The periodic excitation of these elements results in a temperature span across the device. By assuming heat exchange with the environment and a low thermal contact resistivity between the elements, we show that a device with 15 elements and an EC effect of 1.2 K achieves a temperature span between the hot and cold sides of the device equal to 12.6 K. Since the temperature span can be controlled by the number of elements in the device, the results suggest that in combination with the so-called “giant” EC effect (ΔTEC ≥ 10 K), a very large temperature span would be possible. The results of this work should motivate the development of efficient EC refrigeration systems based on a coupling of the EC and EM effects.
Dust ion-acoustic cnoidal waves in a plasma with two temperature superthermal electrons
Authors: Saini N. S. , Sethi Papihra
Published: October 2016

An investigation of dust ion-acoustic (DIA) cnoidal waves in unmagnetized collisionless plasma consisting of two temperature superthermal electrons, inertial warm ions, and negatively charged dust grains is presented. Reductive perturbation technique has been used to derive the modified Korteweg-de Vries (mKdV) equation for the study of nonlinear periodic waves. Further, applying the Sagdeev potential approach, energy balance equation is derived. Using the expression for Sagdeev potential in expanded form, the cnoidal wave solution is determined. Both positive and negative potential (compressive and rarefactive) nonlinear DIA cnoidal structures are observed. The effects of parameters like the number density of cold electrons, superthermality of hot and cold electrons, ions to hot electrons temperature ratio, and dust to ion density ratio on the characteristics of DIA cnoidal waves are analyzed.
Mathematical model for a microgrid consisting of wind turbine, PV panels, and energy storage unit
Authors: Ufluoğlu Emrah Erdem , Kayakutlu Gülgün
Published: October 2016

Micro grids are inclined to use renewable energy sources within the availability limits. Energy storage improved the management of hybrid energy resources used in parallel with the grid. This study models the hybrid usage of wind and solar energies as a support for the grid with the availability of batteries. A mixed integer mathematical model is proposed to schedule the use of different resources minimizing the cost following the power market. Capacity, energy balancing and demand constraints are taken into account for this purpose. This model can be used as a decision support system for micro grid load planning.
Variable pitch blades: An approach for improving performance of Darrieus wind turbine
Authors: Sagharichi A. , Maghrebi M. J. , ArabGolarcheh A.
Published: October 2016

Unlike horizontal axis turbines, the Darrieus-type wind turbines have less efficiency and suffer from the self-starting inability. The effects of fixed and variable blade pitch angle as an idea for improving the performance of Darrieus turbine have been investigated using the CFD analysis, and a pitching system (variable pitch Darrieus-type wind turbine) has been proposed that can reduce both the blades oscillating motion and the magnitude of angle of attack in one revolution compared to that of the Darrieus-type wind turbines. In this study, the method of computational fluid dynamics with moving mesh has been used for analyzing the unsteady two-dimensional flow simulation. The numerical results show that the SST k-ω turbulence model matches well with the experimental results and can capture the flow separation phenomenon at low tip speed ratios. Also, it was observed that a small negative fixed pitch angle of −3° can delay the separation and improve the performance of wind turbine. The numerical simulation also showed that the variable-pitch blade turbine can reduce or eliminate the flow separation on its blades at a lower tip speed ratios than that of the fixed pitch blades. This result increases the starting torque and obtaining high efficiency with decreasing in torque ripple on blades during the turbine operation compared to that of the fixed-pitch blade Darrieus turbine.
Regulated large-scale nucleosome density patterns and precise nucleosome positioning correlate with V(D)J recombination
Authors: Pulivarthy Sandhya R. , Lion Mattia , Kuzu Guray , Matthews Adam G. W. , Borowsky Mark L. , Morris John , Kingston Robert E. , Dennis Jonathan H. , Tolstorukov Michael Y. , Oettinger Marjorie A.
Published: October 2016

Significance

Immunoglobulin and T-cell receptor genes are assembled in lymphoid cells from gene fragments by the process known as V(D)J recombination, which is initiated by the recombination activating gene (RAG)1/RAG2 recombinase. To ensure that recombination occurs only in the correct cell type and at the right developmental stage, multiple layers of regulation are necessary, including specific modifications of chromatin. We show that nucleosome positioning is another important factor in this regulation. Developmentally regulated changes in nucleosome positioning help to guide RAG1/RAG2 to the correct sites in recombinationally active cells. These changes occur on the scale of hundreds of kilobases, a form of regulation not typically seen in the rest of the mammalian genome.
Enhancer priming by H3K4 methyltransferase MLL4 controls cell fate transition
Authors: Wang Chaochen , Lee Ji-Eun , Lai Binbin , Macfarlan Todd S. , Xu Shiliyang , Zhuang Lenan , Liu Chengyu , Peng Weiqun , Ge Kai
Published: October 2016

Significance

Transcriptional enhancers control cell-identity gene expression and thus determine cell identity. Enhancers are primed by histone H3K4 mono-/di-methyltransferase MLL4 before they are activated by histone H3K27 acetyltransferase p300. Here, we show that MLL4 is dispensable for cell-identity maintenance but essential for cell fate transition using several model systems including embryonic stem cell (ESC) differentiation toward somatic cells and somatic cell reprogramming into ESC-like cells. Mechanistically, MLL4 is dispensable for maintaining p300 binding on active enhancers of cell-identity genes but is required for p300 binding on enhancers activated during cell fate transition. These results indicate that, although enhancer priming by MLL4 is dispensable for cell-identity maintenance, it controls cell fate transition by orchestrating p300-mediated enhancer activation.
Activation of
SAT1
engages polyamine metabolism with p53-mediated ferroptotic responses
Authors: Ou Yang , Wang Shang-Jui , Li Dawei , Chu Bo , Gu Wei
Published: October 2016

Significance

Although it is commonly accepted that p53-mediated cell-cycle arrest, apoptosis, and senescence all serve as major mechanisms of tumor suppression, accumulating evidence indicates that other activities of p53, such as ferroptosis, are also critical for tumor suppression. However, the molecular mechanisms by which p53-mediated ferroptosis operates are not completely understood. In this study, we discovered that p53 can execute ferroptotic cell-death responses by directly activating its target gene
SAT1
, coded for the spermidine/spermine
N

1

-acetyltransferase 1. These data indicate a regulatory role of p53 in polyamine metabolism and reveal that p53-mediated activation of SAT1 contributes significantly to ferroptotic responses. Thus, p53 may engage multiple metabolic pathways with ferroptotic cell-death responses for tumor suppression.
Aging, memory, and nonhierarchical energy landscape of spin jam
Authors: Samarakoon Anjana , Sato Taku J. , Chen Tianran , Chern Gai-Wei , Yang Junjie , Klich Israel , Sinclair Ryan , Zhou Haidong , Lee Seung-Hun
Published: October 2016

Significance

Our bulk susceptibility and Monte Carlo simulation study of aging and memory effects in densely populated frustrated magnets (spin jam) and in a dilute magnetic alloy (spin glass) indicates a nonhierarchical landscape with a wide and nearly flat but rough bottom for the spin jam and a hierarchical rugged funnel-type landscape for the spin glass.
Disorder drives cooperative folding in a multidomain protein
Authors: Gruszka Dominika T. , Mendonça Carolina A. T. F. , Paci Emanuele , Whelan Fiona , Hawkhead Judith , Potts Jennifer R. , Clarke Jane
Published: October 2016

Significance

Understanding the role played by disorder in biology is becoming increasingly important. Disordered proteins are central to signaling, development, initiation of transcription, and other vital cellular processes. How and why disordered proteins are used is not entirely clear, but disorder can be important in allostery, facilitate regulatory posttranslational modification, and allow rapid and specific but promiscuous binding. Here, our investigations of biofilm-promoting protein SasG illustrate that disorder can play another role. We show that the intrinsic disorder of one-half of the domains is important for imparting long-range cooperativity in folding of a large multidomain protein—allowing formation of a small local element of structure to precipitate cooperative folding of adjacent disordered domains across a length scale of ∼10 nm.