bluuebunny/crossref_metadata_2025 huggingface dataset:
Coping with cross-reactive carbohydrate determinants in allergy diagnosis
Authors: Altmann Friedrich
Published: June 2016

A relevant proportion of allergy diagnosis is accomplished by in vitro determination of specific immunglobulin E (sIgE) to extracts from suspected allergens. Such extracts inevitably contain glycoproteins, which may react with patients’ IgE. In the case of plant and insect allergens, the relevant epitope structure is an α-1,3-fucose on the Asn-linked sugar residue of so-called N-glycans. Due to their wide distribution, N-glycans carrying this epitope are known as “cross-reactive carbohydrate determinant(s)” (CCD[s]). About 15 years of awareness allow the conclusion that anti-CCD IgE does not cause noticeable clinical symptoms. In consequence, diagnostic results arising from CCD reactivity must be rated as false positives. With up to 30 % of CCD reactive patients, this can be regarded as a serious problem.

Another cross-reactive carbohydrate determinant became notorious as a potential cause of anaphylactic reactions to a recombinant glycoprotein drug carrying α-1,3-galactose. This galactose-containing determinant (GalCD, galactose containing cross-reactive carbohydrate determinant) was supposed as a trigger for delayed allergic reactions to red meat in several cases. Thus, α-1,3-galactose may have clinical relevance in certain cases – possibly as a result of tick bites. Often, however, GalCDs probably cause false-positive results with milk and meat extracts. No clear evidence for the role of other non-human carbohydrate structures such as N-glycolylneuraminic acid as CCD has been presented so far.

Remedies for sIgE based in vitro diagnosis come in the form of non-glycosylated recombinant allergen components or of specific CCD inhibitors. The high potential of recombinant allergens is optimally realized in the context of component resolved diagnosis using allergen arrays with more than 100 components, whereas CCD inhibitors increase the specificity of conventional extract-based diagnosis. Reagents for the detection and inhibition of CCDs from plants and insects have been developed, whereas tools for GalCDs of milk and meat lag behind.
Update on ultrasensitive technologies to facilitate research on blood biomarkers for central nervous system disorders
Authors: Andreasson Ulf , Blennow Kaj , Zetterberg Henrik
Published: June 2016

Most research on fluid biomarkers for central nervous system (CNS) disorders has so far been performed using cerebrospinal fluid (CSF) as the biomarker source. CSF has the advantage of being closer to the brain than serum or plasma with a relative enrichment of CNS‐specific proteins that are present at very low concentrations in the blood and thus difficult to reliably quantify using standard immunochemical technologies. Recent technical breakthroughs in the field of ultrasensitive assays have started to change this. Here, we review the most established ultrasensitive quantitative technologies that are currently available to general biomarker laboratories and discuss their use in research on biomarkers for CNS disorders.
Gender Dysphoria and Social Anxiety: An Exploratory Study in Spain
Authors: Bergero-Miguel Trinidad , García-Encinas María A. , Villena-Jimena Amelia , Pérez-Costillas Lucía , Sánchez-Álvarez Nicolás , de Diego-Otero Yolanda , Guzman-Parra Jose
Published: June 2016

Introduction

Social anxiety in gender dysphoria is still under investigation.

Aim

To determine the prevalence and associated factors of social anxiety in a sample of individuals with gender dysphoria.

Methods

A cross-sectional design was used in a clinical sample attending a public gender identity unit in Spain. The sample consisted of 210 individuals (48% trans female and 52% trans male).

Main outcome measures

Mini-International Neuropsychiatric Interview (MINI) for diagnosis of social anxiety disorder, Structured Clinical Interview, Exposure to Violence Questionnaire (EVQ), Beck Depression Inventory (BDI-II), and Functional Social Support Questionnaire (Duke-UNC-11).

Results

Of the total sample, 31.4% had social anxiety disorder. Social anxiety disorder was highly correlated with age (r = −0.181; CI = 0.061–0.264; P = .009) and depression (r = 0.345; CI = 0.213–0.468; P < .001); it is strongly associated to current cannabis use (relative risk [RR] = 1.251; CI = 1.070–1.463; P = .001) and lifetime suicidal ideation (RR = 1.902; CI 1.286–2.814; P < .001). Moreover, it is significantly associated to lifetime nonsuicidal self-injury (RR = 1.188; CI 1.018–1.386; P = .011), nationality (RR = 7.792; CI 1.059–57.392; P = .013), perceived violence at school during childhood and adolescence (r = 0.169; CI = 0.036–0.303; P = .014), unemployment (RR = 1.333; CI 1.02–1.742; P = .021), and hospitalization of parents in childhood (RR = 1.146; CI = 1.003–4.419; P = .046). Using multivariable analysis, the highly significant variables within the model were depression score (odds ratio [OR] = 1.083; CI = 1.045–1.123; P < .001) and current cannabis use (OR = 3.873; CI = 1.534–9.779, P = .004), also age (OR = 0.948; CI = 0.909–0.989; P = .012), hospitalization of parents during childhood (OR = 2.618; CI = 1.107–6.189; P = .028), and nationality (OR = 9.427; CI = 1.065–83.457; P = .044) were associated with social anxiety disorder.

Conclusion

This study highlights the necessity of implementing actions to prevent and treat social anxiety in this high-risk population.
Haloperidol inactivates AMPK and reduces tau phosphorylation in a tau mouse model of Alzheimer's disease
Authors: Koppel Jeremy , Jimenez Heidy , Adrien Leslie , Greenwald Blaine S. , Marambaud Philippe , Cinamon Ezra , Davies Peter
Published: June 2016

Introduction

The use of antipsychotic medications in Alzheimer's disease has been associated with an increased risk of mortality in clinical trials. However, an older postmortem literature suggests that those with schizophrenia treated in an era of exclusively conventional antipsychotic medications had a surprisingly low incidence of tau pathology. No previously published studies have investigated the impact of conventional antipsychotic exposure on tau outcomes in a tau mouse model of AD.

Methods

In two experiments, transgenic rTg (tauP301L) 4510 tau mice were treated with either haloperidol or vehicle and phosphotau epitopes were quantified using high‐sensitivity tau ELISA.

Results

After treatments of 2 and 6 week's duration, mice treated with haloperidol evidenced a significant reduction in tau phosphorylation associated with an inactivation of the tau kinase AMPK.

Discussion

The data suggest that D2 receptor blockade reduces tau phosphorylation in vivo. Future studies are necessary to investigate the impact of this reduction on tau neuropathology.
Multi-scale Holocene Asian monsoon variability deduced from a twin-stalagmite record in southwestern China
Authors: Huang Wei , Wang Yongjin , Cheng Hai , Edwards Richard Lawrence , Shen Chuan-Chou , Liu Dianbing , Shao Qingfeng , Deng Chao , Zhang Zhenqiu , Wang Quan
Published: June 2016

We present two isotopic (δ18O and δ13C) sequences of a twin-stalagmite from Zhuliuping Cave, southwestern China, with 230Th dates from 14.6 to 4.6 ka. The stalagmite δ18O record characterizes orbital- to decadal-scale variability of Asian summer monsoon (ASM) intensity, with the Holocene optimum period (HOP) between 9.8 and 6.8 ka BP which is reinforced by its co-varying δ13C data. The large multi-decadal scale amplitude of the cave δ18O indicates its high sensitivity to climate change. Four centennial-scale weak ASM events during the early Holocene are centered at 11.2, 10.8, 9.1 and 8.2 ka. They can be correlated to cold periods in the northern high latitudes, possibly resulting from rapid dynamics of atmospheric circulation associated with North Atlantic cooling. The 8.2 ka event has an amplitude more than two-thirds that of the Younger Dryas (YD), and is significantly stronger than other cave records in the Asia monsoon region, likely indicating a more severe dry climate condition at the cave site. At the end of the YD event, the δ13C record lags the δ18O record by 300–500 yr, suggesting a multi-centennial slow response of vegetation and soil processes to monsoon enhancement.
Climatic interpretation of loess-paleosol sequences at Mobarakabad and Aghband, Northern Iran
Authors: Ghafarpour Amin , Khormali Farhad , Balsam William , Karimi Alireza , Ayoubi Shamsollah
Published: June 2016

Loess accumulation and paleosol formation are important Quaternary geoarchives in northern Iran. Two loess-paleosol sequences at Mobarakabad and Aghband were examined using soil morphology and micromorphology, mineralogy, magnetic susceptibility (MS), free Fe oxides and calcium carbonate equivalent. The loess-paleosol sequences provide a record of changes in paleo-rainfall in the northern Iran. Micromorphological and MS differences between the loess and paleosols in the sections reflect changes in climate. The different behaviors of magnetic susceptibility between Aghband and Mobar-akabad loess are mainly produced by their different pedogenic environments, topography and climatic conditions. As a result, the MS at the Mobarakabad section is much higher than at Aghband. Paleoeco-logical reconstructions coupled with magnetic depletion in paleosols at Mobarakabad suggest a wetter climate dominating during the formation of the paleosols.
Coping with Multiple Institutional Logics: Temporal Process of Institutional Work during the Emergence of the One Foundation in China
Authors: Liu Yuhuan , Zhang Chenjian , Jing Runtian
Published: June 2016

An increasing body of research has applied an institutional perspective to understand actors’ responses to conflicting institutional logics and the creation process of new organizational forms. Although China provides a natural, real-time laboratory to study this topic, scant empirical research has been done. Moreover, we find it is insufficient to apply current frameworks, which have been mainly driven by studies conducted in Western contexts, to study actors’ responses to institutional multiplicity in China, especially in its emerging non-profit sector. This article fills research gaps by providing an in-depth case analysis of the creation and legitimation process of the One Foundation – the first independent charity foundation established by civic individuals in China. Our study shows that the coexisting and competing relationship among state, civil society, social mission, and market logics provides impetus for organizational change and innovation. This article theorizes a temporal model by showing that actors seek provisional solutions in different organizational stages and gradually develop capabilities to progress institutional work from individual to organizational and to societal level to achieve their goals. By showing how a charity foundation plays a role as a change agent, this article also sheds light on the condition and process that drive innovation in China's non-profit sector.
Rethinking the Literature on the Performance of Chinese Multinational Enterprises
Authors: Rugman Alan M. , Nguyen Quyen T. K. , Wei Ziyi
Published: June 2016

We synthesize the literature on Chinese multinational enterprises (MNEs) and find that much of the prior research is based on as few as a dozen case studies of Chinese firms. They are so case-specific that it has led to a misplaced call for new theories to explain Chinese firms’ internationalization. In an attempt to better relate theory with empirical evidence, we examine the largest 500 Chinese manufacturing firms. We aim to find out the number of Chinese manufacturing firms to be true MNEs by definition, and to examine their financial performance relative to global peers using the financial benchmarking method. We develop our theoretical perspectives from new internalization theory. We find that there are only 49 Chinese manufacturing firms to be true MNEs, whereas the rest are purely domestic firms. Their performance is poor relative to global peers. Chinese MNEs have home country bound firm-specific advantages (FSAs), which are built upon home country-specific advantages (home CSAs). They have not yet developed advanced management capabilities through recombination with host CSAs. Essentially, they acquire foreign firms to increase their sales in domestic market, but they fail to be competitive internationally and to achieve superior performance in overseas operations. Our findings have important strategic implications for managers, public policy makers, and academic research.
Nutritional status of lactating women in Bogor district, Indonesia: cross-sectional dietary intake in three economic quintiles and comparison with pre-pregnant women
Authors: Madanijah Siti , Rimbawan Rimbawan , Briawan Dodik , Zulaikhah Zulaikhah , Andarwulan Nuri , Nuraida Lilis , Sundjaya Tonny , Murti Laksmi , Bindels Jacques
Published: June 2016

The way in which women accommodate for their increased nutritional needs during the lactation period is poorly investigated. In a cross-sectional study involving 220 lactating women (LW), equally distributed in economic quintiles (Q2, Q3, Q4), we investigated whether habitual dietary intake of LW differed from that of 200 pre-pregnant women (PPW) studied using the same methodology. Differences in dietary intake and nutrition sufficiency according to economic status were also investigated. Dietary intake data were collected using 2×24-h dietary recalls and FFQ. Energy, protein, Fe, Ca, Zn and vitamins A and C intakes were calculated utilising local food composition tables and were compared against Indonesian recommendations for adequacy. Energy and protein intakes <70 % of the recommendation and Fe, Ca, Zn and vitamins A and C intakes <77 % of the recommendation were considered insufficient. Except for Zn, dietary intakes of all studied nutrients were higher in LW compared with PPW. However, for all studied nutrients, dietary intake was insufficient in >25 % of LW. For Q2-LW, this proportion was >50 %, except for protein. LW across all studied economic quintiles approximately doubled their vegetable intake, and 71 % of LW indicated a belief that this enhances lactation performance. Biochemical status parameters were analysed in a subset of forty-five women. Anaemia as well as Fe, Zn and Se deficiencies were prevalent among LW, supporting the nutrient intake deficiency data. Despite increasing intakes in LW compared with PPW, habitual diets in the study area do not provide for daily nutrient requirements in substantial proportions for both LW and PPW across all investigated economic groups.
The United States confronts Ebola: suasion, executive action and fragmentation
Authors: Greer Scott L. , Singer Phillip M.
Published: June 2016

The United States’ experience with the Ebola virus in 2014 provides a window into US public health politics. First, the United States provided a case study in the role of suasion and executive action in the management of public health in a fragmented multi-level system. The variable capacity of different parts of the United States to respond to Ebola on the level of hospitals or state governments, and their different approaches, show the limitations of federal influence, the importance of knowledge and executive energy, and the diversity of both powerful actors and sources of power. Second, the politics of Ebola in the United States is a case study in the politics of partisan blame attribution. The outbreak struck in the run-up to an election that was likely to be good for the Republican party, and the election dominated interest in and opinions of Ebola in both the media and public opinion. Democratic voters and media downplayed Ebola while Republican voters and media focused on the outbreak. The media was a key conduit for this strategic politicization, as shown in the quantity, timing and framing of news about Ebola. Neither fragmentation nor partisanship appears to be going away, so understanding the politics of public health crises will remain important.
Design and engineering of artificial oxygen-activating metalloenzymes
Authors: Nastri Flavia , Chino Marco , Maglio Ornella , Bhagi-Damodaran Ambika , Lu Yi , Lombardi Angela
Published: June 2016

Several tools are nowadays available for the design and engineering of artificial oxygen-activating metalloenzymes, with efficiency comparable to that of natural enzymes.
Magnetic field analysis of novel spherical actuators with three-dimensional pole arrays
Authors: Yan Liang , Liang Fengqi , Jiao Zongxia , Wang Tianyi
Published: June 2016

Spherical actuator is an electric device that can achieve multiple degree-of-freedom rotary motions in a single joint. Permanent magnet array is a key factor that influences the output performance of electromagnetic spherical actuators. In this paper, a novel three-dimensional (3D) pole array is proposed to improve the system flux density and thus the output performance. Analysis of magnetic field distribution is extremely important for spherical actuators with 3D magnet arrays. Thus, the investigation of magnetic field is conducted in analytical, numerical, and experimental ways. The general solution of magnetic scalar potential in 3D space is formulated analytically based on Laplace’s equations and spherical harmonics, and then specific solutions of the magnetic scalar potential and magnetic flux density are obtained by using boundary conditions. Numerical computation is utilized to validate the analytical model and to facilitate the observation of the magnetic field variation. A research prototype and a testing platform of magnetic field have been developed for experimental study. The testing platform can move the probe to any position around the spherical actuator and measure the flux density automatically. Experiments are conducted to obtain the flux distribution. Both numerical and experimental results validate the analytical model well.
Magnetocaloric properties of Eu1−xLaxTiO3 (0.01 ≤ x ≤ 0.2) for cryogenic magnetic cooling
Authors: Rubi Km , Midya A. , Mahendiran R. , Maheswar Repaka D. V. , Ramanujan R. V.
Published: June 2016

We report magnetic and magnetocaloric (MCE) properties of polycrystalline Eu1−xLaxTiO3 samples over a wide composition range (0.01 ≤ x ≤ 0.20). It is found that the ground state changes from antiferromagnetic for x = 0.01 (TN = 5.2 K) to ferromagnetic for x ≥ 0.03 and the ferromagnetic Curie temperature increases from TC = 5.7 K for x = 0.03 to TC = 7.9 K for x = 0.20. The x = 0.01 sample shows a large reversible isothermal magnetic entropy change of −ΔSm = 23 (41.5) J/kg K and adiabatic temperature change of ΔTad = 9 (17.2) K around 6.7 K for a field change of μ0ΔH = 2 (5) Tesla. Although the peak value of −ΔSm decreases as La content increases, it is impressive in x = 0.2(−ΔSm = 31.41 J/kg K at T = 7.5 K for μ0ΔH = 5 T). The large value of MCE arises from suppression of the spin entropy associated with the localized moment (J = 7/2) of Eu2+:4f7 ions. This large MCE over a wide compositional range suggests that the Eu1−xLaxTiO3 series could be useful for magnetic cooling below 40 K.
Topic segmentation via community detection in complex networks
Authors: de Arruda Henrique F. , Costa Luciano da F. , Amancio Diego R.
Published: June 2016

Many real systems have been modeled in terms of network concepts, and written texts are a particular example of information networks. In recent years, the use of network methods to analyze language has allowed the discovery of several interesting effects, including the proposition of novel models to explain the emergence of fundamental universal patterns. While syntactical networks, one of the most prevalent networked models of written texts, display both scale-free and small-world properties, such a representation fails in capturing other textual features, such as the organization in topics or subjects. We propose a novel network representation whose main purpose is to capture the semantical relationships of words in a simple way. To do so, we link all words co-occurring in the same semantic context, which is defined in a threefold way. We show that the proposed representations favor the emergence of communities of semantically related words, and this feature may be used to identify relevant topics. The proposed methodology to detect topics was applied to segment selected Wikipedia articles. We found that, in general, our methods outperform traditional bag-of-words representations, which suggests that a high-level textual representation may be useful to study the semantical features of texts.
Reconstruction of neuronal input through modeling single-neuron dynamics and computations
Authors: Qin Qing , Wang Jiang , Yu Haitao , Deng Bin , Chan Wai-lok
Published: June 2016

Mathematical models provide a mathematical description of neuron activity, which can better understand and quantify neural computations and corresponding biophysical mechanisms evoked by stimulus. In this paper, based on the output spike train evoked by the acupuncture mechanical stimulus, we present two different levels of models to describe the input-output system to achieve the reconstruction of neuronal input. The reconstruction process is divided into two steps: First, considering the neuronal spiking event as a Gamma stochastic process. The scale parameter and the shape parameter of Gamma process are, respectively, defined as two spiking characteristics, which are estimated by a state-space method. Then, leaky integrate-and-fire (LIF) model is used to mimic the response system and the estimated spiking characteristics are transformed into two temporal input parameters of LIF model, through two conversion formulas. We test this reconstruction method by three different groups of simulation data. All three groups of estimates reconstruct input parameters with fairly high accuracy. We then use this reconstruction method to estimate the non-measurable acupuncture input parameters. Results show that under three different frequencies of acupuncture stimulus conditions, estimated input parameters have an obvious difference. The higher the frequency of the acupuncture stimulus is, the higher the accuracy of reconstruction is.
Two symmetric n-type interfaces SrTiO3/LaAlO3 in perovskite: Electronic properties from density functional theory
Authors: Reshak A. H. , Abu-Jafar M. S. , Al-Douri Y.
Published: June 2016

The first principles study of the (001) two symmetric n-type interfaces between two insulating perovskites, the nonpolar SrTiO3 (STO), and the polar LaAlO3 (LAO) was performed. We have analyzed the formation of metallic interface states between the STO and LAO heterointerfaces by using the all-electron full-potential linearized augmented plane-wave approach based on the density functional theory, within the local density approximation, the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA), and the Engel-Vosko GGA (EVGGA) formalism. It has been found that some bands cross the Fermi energy level (EF), forming a metallic nature of two symmetric n-type 6.5STO/1.5LAO interfaces with density of states at EF, N(EF) of about 3.56 (state/eV/unit cell), and bare electronic specific heat coefficient (γ) of about 0.62 mJ/(mol cell K2). The electronic band stature and the partial density of states in the vicinity of EF are mainly originated from Ti1,2,3,4-3dxy orbitals. These bands are responsible for the metallic behavior and the forming of the Fermi surface of the two symmetric n-type 6.5STO/1.5LAO interfaces. To obtain a clear map of the valence band electronic charge density distribution of the two symmetric n-type 6.5STO/1.5LAO interfaces, we have investigated the bond's nature and the interactions between the atoms. It reveals that the charge is attracted towards O atoms as it is clear that the O atoms are surrounded by uniform blue spheres which indicate the maximum charge accumulation.
The impact of collisionality, FLR, and parallel closure effects on instabilities in the tokamak pedestal: Numerical studies with the NIMROD code
Authors: King J. R. , Pankin A. Y. , Kruger S. E. , Snyder P. B.
Published: June 2016

The extended-MHD NIMROD code [C. R. Sovinec and J. R. King, J. Comput. Phys. 229, 5803 (2010)] is verified against the ideal-MHD ELITE code [H. R. Wilson et al., Phys. Plasmas 9, 1277 (2002)] on a diverted tokamak discharge. When the NIMROD model complexity is increased incrementally, resistive and first-order finite-Larmour radius effects are destabilizing and stabilizing, respectively. The full result is compared to local analytic calculations which are found to overpredict both the resistive destabilization and drift stabilization in comparison to the NIMROD computations.
Chaotic behavior of collective ion dynamics in the presence of an external static magnetic field
Authors: Poria Swarup , Ghosh Samiran
Published: June 2016

The two-dimensional nonlinear collective ion dynamics in the presence of external magnetic field in an electron-ion plasma is investigated. The analysis is performed for traveling plane waves to elucidate the various aspects of the phase-space dynamics. The presence of magnetic field makes the dynamics of the nonlinear wave complex with a complicated phase-space behavior. Thus, the nonlinear wave supports a wide class of nonlinear structures viz., single soliton, multi-soliton, periodic, and quasi-periodic oscillations depending on the values of M (Mach number) and Ω (the ratio of ion gyro-frequency to the ion plasma frequency). The computational results predict the chaotic behavior of the nonlinear wave and the transition to chaos takes place when Ω≳0.35 depending on the direction of propagation and the value of M. The amplitude of the wave depends on the obliqueness of the propagation and Mach number, whereas the magnetic field changes the dispersion properties of the wave.
Simulation of optical response functions in molecular junctions
Authors: Gao Yi , Galperin Michael
Published: June 2016

We discuss theoretical approaches to nonlinear optical spectroscopy of molecular junctions. Optical response functions are derived in a form convenient for the implementation of Green function techniques, and their expressions in terms of pseudoparticle nonequilibrium Green functions are proposed. The formulation allows to account for both intramolecular interactions and hybridization of molecular states with those of contacts. Within a generic model and utilizing two-dimensional optical spectroscopy as an example, the methodology is compared with exact simulations and is shown to work where the traditional Liouville space approach fails.
Adsorbed states of chlorophenol on Cu(110) and controlled switching of single-molecule junctions
Authors: Okuyama H. , Kitaguchi Y. , Hattori T. , Ueda Y. , Ferrer N. G. , Hatta S. , Aruga T.
Published: June 2016

A molecular junction of substituted benzene (chlorophenol) is fabricated and controlled by using a scanning tunneling microscope (STM). Prior to the junction formation, the bonding geometry of the molecule on the surface is characterized by STM and electron energy loss spectroscopy (EELS). EELS shows that the OH group of chlorophenol is dissociated on Cu(110) and that the molecule is bonded nearly flat to the surface via an O atom, with the Cl group intact. We demonstrate controlled contact of an STM tip to the “available” Cl group and lift-up of the molecule while it is anchored to the surface via an O atom. The asymmetric bonding motifs of the molecule to the electrodes allow for reversible control of the junction.
Microhydration of LiOH: Insight from electronic decays of core-ionized states
Authors: Kryzhevoi Nikolai V.
Published: June 2016

We compute and compare the autoionization spectra of a core-ionized LiOH molecule both in its isolated and microhydrated states. Stepwise microhydration of LiOH leads to gradual elongation of the Li–OH bond length and finally to molecular dissociation. The accompanying changes in the local environment of the OH− and Li+ counterions are reflected in the computed O 1s and Li 1s spectra. The role of solvent water molecules and the counterion in the spectral shape formation is assessed. Electronic decays of the microhydrated LiOH are found to be mostly intermolecular since the majority of the populated final states have at least one outer-valence vacancy outside the initially core-ionized ion, mainly on a neighboring water molecule. The charge delocalization occurs through the intermolecular Coulombic and electron transfer mediated decays. Both mechanisms are highly efficient that is partly attributed to hybridization of molecular orbitals. The computed spectral shapes are sensitive to the counterion separation as well as to the number and arrangement of solvent molecules. These sensitivities can be used for studying the local hydration structure of solvated ions in aqueous solutions.
Simultaneous measurement of electrical and thermal conductivities of suspended monolayer graphene
Authors: Wang Haidong , Kurata Kosaku , Fukunaga Takanobu , Ago Hiroki , Takamatsu Hiroshi , Zhang Xing , Ikuta Tatsuya , Takahashi Koji , Nishiyama Takashi , Takata Yasuyuki
Published: June 2016

We measured both in-plane electrical and thermal properties of the same suspended monolayer graphene using a novel T-type sensor method. At room temperature, the values are about 240 000 Ω−1 m−1 and 2100 W m−1 K−1 for the electrical and thermal conductivities, respectively. Based on the Wiedemann-Franz law, the electrons have negligible contribution to the thermal conductivity of graphene, while the in-plane LA and TA modes phonons are the dominant heat carriers. In monolayer graphene, the absence of layer-layer and layer-substrate interactions enhances the contribution of long wave-length phonons to the heat transport and increases the thermal conductivity accordingly. The reported method and experimental data of suspended monolayer graphene are useful for understanding the basic physics and designing the future graphene electronic devices.
Microstructure and composition analysis of low-Z/low-Z multilayers by combining hard and resonant soft X-ray reflectivity
Authors: Rao P. N. , Rai S. K. , Srivastava A. K. , Ganguli T. , Dhawan R. , Naik P. A.
Published: June 2016

Microstructure and composition analysis of periodic multilayer structure consisting of a low electron density contrast (EDC) material combination by grazing incidence hard X-ray reflectivity (GIXR), resonant soft X-ray reflectivity (RSXR), and transmission electron microscopy (TEM) are presented. Measurements of reflectivity at different energies allow combining the sensitivity of GIXR data to microstructural parameters like layer thicknesses and interfacing roughness, with the layer composition sensitivity of RSXR. These aspects are shown with an example of 10-period C/B4C multilayer. TEM observation reveals that interfaces C on B4C and B4C on C are symmetric. Although GIXR provides limited structural information when EDC between layers is low, measurements using a scattering technique like GIXR with a microscopic technique like TEM improve the microstructural information of low EDC combination. The optical constants of buried layers have been derived by RSXR. The derived optical constants from the measured RSXR data suggested the presence of excess carbon into the boron carbide layer.
Tunable plasmonic-lattice mode sensors with ultrahigh sensitivities and figure-of-merits
Authors: Sadeghi S. M. , Wing W. J. , Campbell Q.
Published: June 2016

We study the application of plasmonic lattice modes of arrays of closely packed large metallic nanodisks for chemical and biological sensors with ultrahigh sensitivity and refractive index dynamic range. Our results show that by changing the refractive index of the environment the narrow spectral features associated with these collective modes can be shifted by about 250 nm, going from visible (∼650 nm) to infrared (∼900 nm) range without any mode degradation. We attribute this shift to the refractive-index enhancement of the superstrate collective modes of these arrays. This index enhancement allows the arrays to preserve their mode integrity within this range. We show that, because of this feature and the ultra-long range fields of these modes, such structures can offer a unique platform for biosensors based on dielectric-coated metallic nanoparticle arrays. In such structures, the dielectric layers are used to tune the collective modes of the arrays, protect them against environmental degradation, and to prepare bio-functionalized surfaces for certain biological targets. We demonstrate that such a platform allows us to set the operation wavelength of these sensors within the visible-infrared spectral range with sensitivity more than 520 nm/refractive index unit and a figure of merit of about 17.
Interrelationship of in situ growth stress evolution and phase transformations in Ti/W multilayered thin films
Authors: Wan Li , Yu Xiao-xiang , Zhou Xuyang , Thompson Gregory
Published: June 2016

This paper addresses the in situ growth stress evolution and phase transformation of bcc to hcp Ti in Ti/W multilayered thin films. A series of equal layer thicknesses from 20 nm to 1 nm were deposited. As the bilayer thickness reduced, the overall film stress became less compressive until the Ti transformed from hcp (at the larger layer thicknesses) to bcc in the 1 nm/1 nm multilayer. The pseudomorphic bcc stabilization resulted in a recovery of the compressive stress to values near that for the bulk phase stabilized for the 5 nm/5 nm multilayer. A discernable change in stress slope was noted for the bcc to hcp Ti transition as a function of Ti layer thickness. The stress states for each film, during film growth, are rationalized by the lattice matching of the phase with the growth surface. These results are coupled to a molecular dynamics deposition simulation which revealed good agreement with the experimentally observed transformation thickness.
Shift of optical absorption edge in SnO2 films with high concentrations of nitrogen grown by chemical vapor deposition
Authors: Jiang Jie , Lu Yinmei , Meyer Bruno K. , Hofmann Detlev M. , Eickhoff Martin
Published: June 2016

The optical and electrical properties of n-type SnO2 films with high concentrations of nitrogen (SnO2:N) grown by chemical vapor deposition are studied. The carrier concentration increases from 4.1 × 1018 to 3.9 × 1019 cm−3 and the absorption edge shifts from 4.26 to 4.08 eV with increasing NH3 flow rate. Typical Urbach tails were observed from the absorption spectra and the Urbach energy increases from 0.321 to 0.526 eV with increasing NH3 flow rate. An “effective” absorption edge of about 4.61 eV was obtained for all investigated samples from fitting the extrapolations of the Urbach tails. Burstein-Moss effect, electron-impurity, and electron-electron interactions are shown to play a minor role for the shift of the absorption edges in SnO2:N thin films.
Three-dimensional atomic mapping of hydrogenated polymorphous silicon solar cells
Authors: Chen Wanghua , Pareige Philippe , Roca i Cabarrocas Pere
Published: June 2016

Hydrogenated polymorphous silicon (pm-Si:H) is a nanostructured material consisting of silicon nanocrystals embedded in an amorphous silicon matrix. Its use as the intrinsic layer in thin film p-i-n solar cells has led to good cell properties in terms of stability and efficiency. Here, we have been able to assess directly the concentration and distribution of nanocrystals and impurities (dopants) in p-i-n solar cells, by using femtosecond laser-assisted atom probe tomography (APT). An effective sample preparation method for APT characterization is developed. Based on the difference in atomic density between hydrogenated amorphous and crystalline silicon, we are able to distinguish the nanocrystals from the amorphous matrix by using APT. Moreover, thanks to the three-dimensional reconstruction, we demonstrate that Si nanocrystals are homogeneously distributed in the entire intrinsic layer of the solar cell. The influence of the process pressure on the incorporation of nanocrystals and their distribution is also investigated. Thanks to APT we could determine crystalline fractions as low as 4.2% in the pm-Si:H films, which is very difficult to determine by standard techniques, such as X-ray diffraction, Raman spectroscopy, and spectroscopic ellipsometry. Moreover, we also demonstrate a sharp p/i interface in our solar cells.
Development of speckle-free channel-cut crystal optics using plasma chemical vaporization machining for coherent x-ray applications
Authors: Hirano Takashi , Osaka Taito , Sano Yasuhisa , Inubushi Yuichi , Matsuyama Satoshi , Tono Kensuke , Ishikawa Tetsuya , Yabashi Makina , Yamauchi Kazuto
Published: June 2016

We have developed a method of fabricating speckle-free channel-cut crystal optics with plasma chemical vaporization machining, an etching method using atmospheric-pressure plasma, for coherent X-ray applications. We investigated the etching characteristics to silicon crystals and achieved a small surface roughness of less than 1 nm rms at a removal depth of >10 μm, which satisfies the requirements for eliminating subsurface damage while suppressing diffuse scattering from rough surfaces. We applied this method for fabricating channel-cut Si(220) crystals for a hard X-ray split-and-delay optical system and confirmed that the crystals provided speckle-free reflection profiles under coherent X-ray illumination.
Growth and characterization of metamorphic InAs/GaSb tunnel heterojunction on GaAs by molecular beam epitaxy
Authors: Liu Jheng-Sin , Clavel Michael B. , Pandey Rahul , Datta Suman , Meeker Michael , Khodaparast Giti A. , Hudait Mantu K.
Published: June 2016

The structural, morphological, optical, and electrical transport characteristics of a metamorphic, broken-gap InAs/GaSb p-i-n tunnel diode structure, grown by molecular beam epitaxy on GaAs, were demonstrated. Precise shutter sequences were implemented for the strain-balanced InAs/GaSb active layer growth on GaAs, as corroborated by high-resolution X-ray analysis. Cross-sectional transmission electron microscopy and detailed micrograph analysis demonstrated strain relaxation primarily via the formation of 90° Lomer misfit dislocations (MDs) exhibiting a 5.6 nm spacing and intermittent 60° MDs at the GaSb/GaAs heterointerface, which was further supported by a minimal lattice tilt of 180 arc sec observed during X-ray analysis. Selective area diffraction and Fast Fourier Transform patterns confirmed the full relaxation of the GaSb buffer layer and quasi-ideal, strain-balanced InAs/GaSb heteroepitaxy. Temperature-dependent photoluminescence measurements demonstrated the optical band gap of the GaSb layer. Strong optical signal at room temperature from this structure supports a high-quality material synthesis. Current–voltage characteristics of fabricated InAs/GaSb p-i-n tunnel diodes measured at 77 K and 290 K demonstrated two bias-dependent transport mechanisms. The Shockley–Read–Hall generation–recombination mechanism at low bias and band-to-band tunneling transport at high bias confirmed the p-i-n tunnel diode operation. This elucidated the importance of defect control in metamorphic InAs/GaSb tunnel diodes for the implementation of low-voltage and high-performance tunnel field effect transistor applications.
Homoepitaxial nonpolar (10-10) ZnO/ZnMgO monolithic microcavities: Towards reduced photonic disorder
Authors: Zuniga-Perez J. , Kappei L. , Deparis C. , Reveret F. , Grundmann M. , de Prado E. , Jamadi O. , Leymarie J. , Chenot S. , Leroux M.
Published: June 2016

Nonpolar ZnO/ZnMgO-based optical microcavities have been grown on (10-10) m-plane ZnO substrates by plasma-assisted molecular beam epitaxy. Reflectivity measurements indicate an exponential increase of the cavity quality factor with the number of layers in the distributed Bragg reflectors. Most importantly, microreflectivity spectra recorded with a spot size in the order of 2 μm show a negligible photonic disorder (well below 1 meV), leading to local quality factors equivalent to those obtained by macroreflectivity. The anisotropic character of the nonpolar heterostructures manifests itself both in the surface features, elongated parallel to the in-plane c direction, and in the optical spectra, with two cavity modes being observed at different energies for orthogonal polarizations.
A linear-field plasma jet for generating a brush-shaped laminar plume at atmospheric pressure
Authors: Li Xuechen , Li Jiyuan , Chu Jingdi , Zhang Panpan , Jia Pengying
Published: June 2016

A linear-field plasma jet composed of line-to-plate electrodes is used to generate a large-scale brush-shaped plasma plume with flowing argon used as working gas. Through electrical measurement and fast photography, it is found that the plasma plume bridges the two electrodes for the discharge in the positive voltage half-cycle, which behaves like fast moving plasma bullets directed from the anode to the cathode. Compared with the positive discharge, the negative discharge only develops inside the nozzle and propagates much slower. Results also indicate that the gas temperature of the plume is close to room temperature, which is promising for biomedical application.
Determination of subcell open circuit voltages and Iph–Voc curves in multijunction solar cells by sequentially pulsed, monochromatic illumination
Authors: Rutzinger M. , Nesswetter H. , Lugli P. , Bett A. W. , Zimmermann C. G.
Published: June 2016

The open circuit voltages Voc of individual subcells in a multijunction solar cell are measured by illuminating a given subcell with a pulse of spatially homogeneous, nearly monochromatic light with a rising edge in the μs regime. The influence of luminescent coupling and semi-transparency on Voc is eliminated by over-illuminating all subcells below this subcell with a preceding light pulse. By using a suns-Voc approach, the two-diode model dark saturation currents of each subcell are extracted. The proposed method is verified experimentally as well as through simulations on three and four-junction solar cells.
Well separated trion and neutral excitons on superacid treated MoS2 monolayers
Authors: Cadiz Fabian , Tricard Simon , Gay Maxime , Lagarde Delphine , Wang Gang , Robert Cedric , Renucci Pierre , Urbaszek Bernhard , Marie Xavier
Published: June 2016

Developments in optoelectronics and spin-optronics based on transition metal dichalcogenide monolayers (MLs) need materials with efficient optical emission and well-defined transition energies. In as-exfoliated MoS2 MLs, the photoluminescence (PL) spectra even at low temperature consist typically of broad, overlapping contributions from neutral, charged excitons (trions) and localized states. Here, we show that in superacid treated MoS2 MLs, the PL intensity increases by up to 60 times at room temperature. The neutral and charged exciton transitions are spectrally well separated in PL and reflectivity at T = 4 K, with linewidth for the neutral exciton of 15 meV, but both transitions have similar intensities compared to the ones in as-exfoliated MLs at the same temperature. Time resolved experiments uncover picoseconds recombination dynamics analyzed separately for charged and neutral exciton emissions. Using the chiral interband selection rules, we demonstrate optically induced valley polarization for both complexes and valley coherence for only the neutral exciton.
PEDOT:PSS with embedded TiO2 nanoparticles as light trapping electrode for organic photovoltaics
Authors: Park Yoonseok , Müller-Meskamp Lars , Vandewal Koen , Leo Karl
Published: June 2016

The performance of organic optoelectronic devices can be improved by employing a suitable optical cavity design beyond the standard plane layer approach, e.g., by the inclusion of periodically or randomly textured structures which increase light incoupling or extraction. One of the simplest approaches is to add an additional layer containing light scattering particles into the device stack. Solution processed poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films are promising for replacing the brittle and expensive indium tin oxide transparent electrode. We use a blend of 100 nm TiO2 scattering particles in PEDOT:PSS solution to fabricate transparent electrode films which also functions as a scattering layer. When utilized in an organic photovoltaic device, a power conversion efficiency of 7.92% is achieved, which is an 8.6% relative improvement compared to a device with a neat PEDOT:PSS electrode without the nanoparticles. This improvement is caused by an increase in short-circuit current due to an improved photon harvesting in the 320 nm–700 nm spectral wavelength range.
Simple microfluidic stagnation point flow geometries
Authors: Dockx Greet , Verwijlen Tom , Sempels Wouter , Nagel Mathias , Moldenaers Paula , Hofkens Johan , Vermant Jan
Published: June 2016

A geometrically simple flow cell is proposed to generate different types of stagnation flows, using a separation flow and small variations of the geometric parameters. Flows with high local deformation rates can be changed from purely rotational, over simple shear flow, to extensional flow in a region surrounding a stagnation point. Computational fluid dynamic calculations are used to analyse how variations of the geometrical parameters affect the flow field. These numerical calculations are compared to the experimentally obtained streamlines of different designs, which have been determined by high speed confocal microscopy. As the flow type is dictated predominantly by the geometrical parameters, such simple separating flow devices may alleviate the requirements for flow control, while offering good stability for a wide variety of flow types.
Direct observation of B-site ordering in LSAT: (La0.3Sr0.7)(Al0.65Ta0.35)O3 single crystal
Authors: Okada S. , Kobayashi S. , Ohashi K. , Nishikawa N. , Tokunaga T. , Sasaki K. , Yamamoto T.
Published: June 2016

B-site atomic column regularity was directly observed in (La0.3Sr0.7)(Al0.65Ta0.35)O3 single crystals by Z-contrast imaging during high-angle annular dark-field scanning transmission electron microscopy. Two types of areas with different B-site regularity were found. One of the ordered structures, which was similar to a previously reported structure, was several tens of nanometers in size and had a rock salt-like regularity owing to variation in the B-site Al/Ta ratio. The other structure existed as disordered-like domains in the (La0.3Sr0.7)(Al0.65Ta0.35)O3 crystal. Fourier transform processing revealed that the disordered-like domains consisted of very fine ordered domains of several nanometers in size. These very fine ordered structures had a different B-site Al/Ta ratio variation with a rock salt-like regularity.
Derivation and application of mathematical model for well test analysis with variable skin factor in hydrocarbon reservoirs
Authors: Liu Pengcheng , Li Wenhui , Xia Jing , Jiao Yuwei , Bie Aifang
Published: June 2016

Skin factor is often regarded as a constant in most of the mathematical model for well test analysis in oilfields, but this is only a kind of simplified treatment with the actual skin factor changeable. This paper defined the average permeability of a damaged area as a function of time by using the definition of skin factor. Therefore a relationship between a variable skin factor and time was established. The variable skin factor derived was introduced into existing traditional models rather than using a constant skin factor, then, this newly derived mathematical model for well test analysis considering variable skin factor was solved by Laplace transform. The dimensionless wellbore pressure and its derivative changed with dimensionless time were plotted with double logarithm and these plots can be used for type curve fitting. The effects of all the parameters in the expression of variable skin factor were analyzed based on the dimensionless wellbore pressure and its derivative. Finally, actual well testing data were used to fit the type curves developed which validates the applicability of the mathematical model from Sheng-2 Block, Shengli Oilfield, China.