bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of neonatal stress on gamma oscillations in hippocampus
Authors: Dricks Sally
Published: July 2016

Chronic early life stress increases adult risk for depression, bipolar disorder and schizophrenia, illnesses characterized by aberrant functions of cognition and memory. We asked whether chronic early life stress disrupts maturation of gamma oscillations, on which these functions depend. Lifelong impairment of the stress response results from separation of rat pups from the dam for three hours per day during a critical period of hippocampal development (PNDs 2–14). Parvalbumin-expressing interneurons, including the basket cell network which is fundamental to gamma oscillations, are reduced in number in post mortem studies of bipolar disorder and schizophrenia and in chronically-stressed adult rats. To determine effects of chronic early life stress on gamma oscillations, we separated pups from dams once each day on PNDs 2–14 and recorded in vitro at PNDs 15–21. In control pups, separated for 15 minutes per day, gamma power had highly significant correlations with both age (p = 0.0022) and weight (p = 0.0024); gamma in pups separated for 180 minutes per day was not correlated with either factor. ANCOVA indicated significant differences between the groups in both measures. These findings indicate that chronic early life stress can disrupt maturation of the gamma oscillation network.
The metabolome of [2-14C](−)-epicatechin in humans: implications for the assessment of efficacy, safety and mechanisms of action of polyphenolic bioactives
Authors: Ottaviani Javier I. , Borges Gina , Momma Tony Y. , Spencer Jeremy P. E. , Keen Carl L. , Crozier Alan , Schroeter Hagen
Published: July 2016

Diet is a major life style factor affecting human health, thus emphasizing the need for evidence-based dietary guidelines for primary disease prevention. While current recommendations promote intake of fruit and vegetables, we have limited understanding of plant-derived bioactive food constituents other than those representing the small number of essential nutrients and minerals. This limited understanding can be attributed to some extent to a lack of fundamental data describing the absorption, distribution, metabolism and excretion (ADME) of bioactive compounds. Consequently, we selected the flavanol (−)-epicatechin (EC) as an example of a widely studied bioactive food constituent and investigated the ADME of [2-14C](−)-epicatechin (300 μCi, 60 mg) in humans (n = 8). We demonstrated that 82 ± 5% of ingested EC was absorbed. We also established pharmacokinetic profiles and identified and quantified >20 different metabolites. The gut microbiome proved to be a key driver of EC metabolism. Furthermore, we noted striking species-dependent differences in the metabolism of EC, an insight with significant consequences for investigating the mechanisms of action underlying the beneficial effects of EC. These differences need to be considered when assessing the safety of EC intake in humans. We also identified a potential biomarker for the objective assessment of EC intake that could help to strengthen epidemiological investigations.
Antennal transcriptome and differential expression of olfactory genes in the yellow peach moth, Conogethes punctiferalis (Lepidoptera: Crambidae)
Authors: Jia Xiao-Jian , Wang Hai-Xiang , Yan Zeng-Guang , Zhang Min-Zhao , Wei Chun-Hua , Qin Xiao-Chun , Ji Wei-Rong , Falabella Patrizia , Du Yan-Li
Published: July 2016

The yellow peach moth (YPM), Conogethes punctiferalis (Guenée), is a multivoltine insect pest of crops and fruits. Antennal-expressed receptors are important for insects to detect olfactory cues for host finding, mate attraction and oviposition site selection. However, few olfactory related genes were reported in YPM until now. In the present study, we sequenced and characterized the antennal transcriptomes of male and female YPM. In total, 15 putative odorant binding proteins (OBPs), 46 putative odorant receptors (ORs) and 7 putative ionotropic receptors (IRs) were annotated and identified as olfactory-related genes of C. punctiferalis. Further analysis of RT-qPCR revealed that all these olfactory genes are primarily or uniquely expressed in male and female antennae. Among which, 3 OBPs (OBP4, OBP8 and PBP2) and 4 ORs (OR22, OR26, OR44 and OR46) were specially expressed in male antennae, whereas 4 ORs (OR5, OR16, OR25 and OR42) were primarily expressed in female antennae. The predicted protein sequences were compared with homologs in other lepidopteran species and model insects, which showed high sequence homologies between C. punctiferalis and O. furnacalis. Our work allows for further functional studies of pheromone and general odorant detection genes, which might be meaningful targets for pest management.
“Cre/loxP plus BAC”: a strategy for direct cloning of large DNA fragment and its applications in Photorhabdus luminescens and Agrobacterium tumefaciens
Authors: Hu Shengbiao , Liu Zhengqiang , Zhang Xu , Zhang Guoyong , Xie Yali , Ding Xuezhi , Mo Xiangtao , Stewart A. Francis , Fu Jun , Zhang Youming , Xia Liqiu
Published: July 2016

Heterologous expression has been proven to be a valid strategy for elucidating the natural products produced by gene clusters uncovered by genome sequencing projects. Efforts have been made to efficiently clone gene clusters directly from genomic DNA and several approaches have been developed. Here, we present an alternative strategy based on the site-specific recombinase system Cre/loxP for direct cloning gene clusters. A type three secretion system (T3SS) gene cluster (~32 kb) from Photorhabdus luminescens TT01 and DNA fragment (~78 kb) containing the siderophore biosynthetic gene cluster from Agrobacterium tumefaciens C58 have been successfully cloned into pBeloBAC11 with “Cre/loxP plus BAC” strategy. Based on the fact that Cre/loxP system has successfully used for genomic engineering in a wide range of organisms, we believe that this strategy could be widely used for direct cloning of large DNA fragment.
Palladium-catalyzed dearomatizing 2,5-alkoxyarylation of furan rings: diastereospecific access to spirooxindoles
Authors: Liu Jianchao , Xu Xiaobing , Li Jiuyi , Liu Bo , Jiang Huanfeng , Yin Biaolin
Published: July 2016

A protocol for Pd-catalyzed intra- and intermolecular 2,5-alkoxyarylation reactions of furans to diastereospecifically synthesize two series of spirooxindoles is reported.
Diffusion and precipitation processes in iron-based silica gardens
Authors: Glaab F. , Rieder J. , García-Ruiz J. M. , Kunz W. , Kellermeier M.
Published: July 2016

The time-dependent dynamic evolution of macroscopic silica garden tubes is shown to strongly depend on the used metal cations.
The thermoelectrochemistry of lithium–glyme solvate ionic liquids: towards waste heat harvesting
Authors: Black Jeffrey J. , Murphy Thomas , Atkin Rob , Dolan Andrew , Aldous Leigh
Published: July 2016

We have investigated the thermoelectrochemical properties of lithium bis(trifluoromethylsulfonyl)imide and tetraglyme mixtures, as dilute electrolytes and solvate ionic liquids.
Effect of cobalt doping on the structural, magnetic and abnormal thermal expansion properties of NaZn13-type La(Fe1−xCox)11.4Al1.6 compounds
Authors: Zhao Yuqiang , Huang Rongjin , Li Shaopeng , Wang Wei , Jiang Xingxing , Lin Zheshuai , Li Jiangtao , Li Laifeng
Published: July 2016

Abnormal thermal expansion behavior mainly depends on their special structural and magnetic properties for La(Fe1−xCox)11.4Al1.6 compounds.
A chemical chaperone induces inhomogeneous conformational changes in flexible proteins
Authors: Hamdane Djemel , Velours Christophe , Cornu David , Nicaise Magali , Lombard Murielle , Fontecave Marc
Published: July 2016

Organic osmolytes are major cellular compounds that favor protein's compaction and stabilization of the native state. Here, we have examined the chaperone effect of the naturally occurring trimethylamine N-oxide (TMAO) osmolyte on a flexible protein.
Ferrocene–quinoxaline Y-shaped chromophores as fascinating second-order NLO building blocks for long lasting highly active SHG polymeric films
Authors: Senthilkumar Kabali , Thirumoorthy Krishnan , Dragonetti Claudia , Marinotto Daniele , Righetto Stefania , Colombo Alessia , Haukka Matti , Palanisami Nallasamy
Published: July 2016

The first example of a Y-shaped ferrocene quinoxaline derivative with high and stable SHG response in polymeric films is reported.
Formation of defect-fluorite structured NdNiOxHy epitaxial thin films via a soft chemical route from NdNiO3 precursors
Authors: Onozuka T. , Chikamatsu A. , Katayama T. , Fukumura T. , Hasegawa T.
Published: July 2016

A new phase of oxyhydride NdNiOxHy with a defect-fluorite structure was obtained by a soft chemical reaction of NdNiO3 epitaxial thin films on a substrate of SrTiO3 (100) with CaH2.
Enhanced thermoelectric performance of CdO : Ag nanocomposites
Authors: Gao Linjie , Wang Shufang , Liu Ran , Zha Xinyu , Sun Niefeng , Wang Shujie , Wang Jianglong , Fu Guangsheng
Published: July 2016

Enhanced thermoelectric performance of CdO : x at% Ag nanocomposites with metallic Ag nanoparticles embedded in the polycrystalline CdO matrix.
Selectivity of solid phase extraction of freshwater dissolved organic matter and its effect on ultrahigh resolution mass spectra
Authors: Raeke Julia , Lechtenfeld Oliver J. , Wagner Martin , Herzsprung Peter , Reemtsma Thorsten
Published: July 2016

Solid phase extracts of freshwater dissolved organic matter are compared to the original sample with use of complementary techniques.
Quantification of 4-hydroxy-2-nonenal-protein adducts in the in vivo gastric digesta of mini-pigs using a GC-MS/MS method with accuracy profile validation
Authors: Delosière Mylène , Santé-Lhoutellier Véronique , Chantelauze Céline , Durand Denys , Thomas Agnès , Joly Charlotte , Pujos-Guillot Estelle , Rémond Didier , Comte Blandine , Gladine Cécile , Guy Alexandre , Durand Thierry , Laurentie Michel , Dufour Claire
Published: July 2016

Quantification of 4-hydroxy-2-nonenal-protein adducts in thein vivogastric digesta of mini-pigs using a validated GC-MS/MS method.
Lab-on-a-disc for simultaneous determination of total phenolic content and antioxidant activity of beverage samples
Authors: Phonchai Apichai , Kim Yubin , Chantiwas Rattikan , Cho Yoon-Kyoung
Published: July 2016

This paper reports the simultaneous determination of TPC and AA of beverages using lab-on-a-disc.
Microfluidic fuel cells for energy generation
Authors: Safdar M. , Jänis J. , Sánchez S.
Published: July 2016

Here, we summarize recent developments which utilize the potential of microfluidic devices for energy generation.
Inoculation of bacteria for the bioremediation of heavy metals contaminated soil by Agrocybe aegerita
Authors: Li Xue , Dong Shunwen , Yao Yuan , Shi Wenjin , Wu Minghui , Xu Heng
Published: July 2016

The combination of mushrooms and bacteria was used as a novel technique to remediate soils polluted by heavy metals.
Evidence for a multivalent effect in inhibition of sulfatases involved in lysosomal storage disorders (LSDs)
Authors: D'Adamio G. , Matassini C. , Parmeggiani C. , Catarzi S. , Morrone A. , Goti A. , Paoli P. , Cardona F.
Published: July 2016

New targets sensitive to multivalency: synthesis of nonavalent pyrrolidine iminosugars.
Retraction: Synthesis of diacylglycerol analogs bearing photoaffinity tags for labelling mammalian diacylglycerol kinase
Authors: Eni Sammy Eni , Rowland Meng , Best Michael D.
Published: July 2016

Retraction of ‘Synthesis of diacylglycerol analogs bearing photoaffinity tags for labelling mammalian diacylglycerol kinase’ by Sammy Eni Eni et al., RSC Adv., 2015, 5, 25457–25461.
Benzimidazole functionalized covalent triazine frameworks for CO2capture
Authors: Tao Liming , Niu Fang , Wang Chao , Liu Jingang , Wang Tingmei , Wang Qihua
Published: July 2016

Benzimidazole functionalized covalent triazine frameworks exhibited high BET surface areas up to 1500 m2g−1, high CO2adsorption capacities up to 21.7 wt% at 273 K, and high CO2/N2selectivities up to 102.7 at a high temperature of 303 K.
1,2,4-Triazole-containing bipolar hosts for blue and green phosphorescent organic light-emitting diodes
Authors: Liu Di , Li Deli , Wang Miao , Li Wei
Published: July 2016

By adjusting the triazole/carbazole ratio, the charge injection and charge balance of novel bipolar host materials are regularly tuned, and 1 : 2 is proved to be the optimal ratio leading to highest efficiencies and slowest efficiency roll-off in blue and green phosphorescence organic light-emitting diodes.
Augmenting College Students' Study of Speech-Language Pathology Using Computer-Based Mini Quiz Games
Authors: Vinney Lisa A. , Howles Les , Leverson Glen , Connor Nadine P.
Published: July 2016

Purpose

This study examined whether undergraduate college students' immediate recall and longer-term retention of introductory voice disorder concepts improved by using mini quiz games (MQGs; interactive knowledge tests in game format) compared with (a) traditional study alone, (b) MQGs and traditional study together, or (c) a no-study control condition.

Method

Ninety-three college students participated in proctored sessions in which they were given a pretest, viewed an online lecture on introductory voice disorder concepts, and then engaged in either no intervention or interventions including traditional study, MQG play, or both MQG play and traditional study, followed by an immediate recall posttest and longer-term retention follow-up test.

Results

Analyses suggested that the effects of all interventions (traditional study, MQG play, and the combination of the 2) were equivalent and resulted in significantly greater improvements from pretest to immediate recall posttest performance than the control condition. In contrast, MQGs and MQGs with traditional study, but not traditional study alone, showed better results for long-term retention than no study.

Conclusion

Results provide preliminary support for the idea that there may be multiple effective learning modes, beyond traditional study, that enhance recall and retention of knowledge foundational to speech-language pathology clinical training and practice.
Use of a Clinical Outcomes Database: A Resource for Health Services Research
Authors: Moore Jaime E.
Published: July 2016

Comparative effectiveness research and patient-centered outcomes are two popular areas of study within health services research. This article will discuss the use of a clinical outcomes database used for the purpose of studying comparative effectiveness and patient-centered outcomes in individuals seen at the University of Wisconsin-Madison Voice and Swallow Clinics. The establishment and use of this database are discussed, including its benefits and limitations as it relates to health services research.
Dynamic analysis of wind turbine gearboxes with unknown‐but‐bounded parameters under random wind excitation
Authors: Wei Sha , Han Qinkai , Peng Zhike , Chu Fulei
Published: July 2016

Dynamic analysis of the gearbox system plays a significant role in wind turbine fault diagnosis. The dynamic behaviour of the gearbox system may be affected by the unavoidable uncertainties of system parameters and external excitations. The dynamic characteristics of the wind turbine gearbox system with uncertainties subjected to random wind excitation are studied. A lumped‐parameter model of a multistage gearbox system under transmission errors, time‐varying mesh stiffness and random wind excitation is established. By using the Chebyshev inclusion function and the Welch method, an interval method for predicting the interval bounds of power spectral density for system responses is proposed. The accuracy of the presented method is verified by comparing with the scanning method. As an example, the effects of different uncertain parameters on the stochastic responses of system are investigated. The result illustrates the effectiveness of the proposed method. It is also shown that the dynamic responses of the system are sensitive to the uncertain stiffness parameters at the intermediate and high‐speed stages. The result is of significant importance for the fault diagnosis in the wind turbine drive train.
Fabrication of poly(L‐lactic acid) porous microspheres via phase inversion emulsion method
Authors: Nie Taotao , Xue Li , Ge Min , Ma Haiyun , Zhang Jinchao
Published: July 2016

Porous microspheres capable of delivering high payloads of biomolecules with suitable biodegradability and biocompatibility would be valuable in delivery systems to aid tissue regeneration. In this work, a facile and scalable technique was induced to prepare poly(L‐lactic acid) (PLLA) porous microspheres by combining an oil‐in‐oil surfactant‐free phase inversion emulsion with thermally induced phase separation method. The morphology and property of the microspheres were investigated by scanning electron microscopy and N2 adsorption test. Comparing to the conventional biodegradable microspheres, the nanoscale topographic structured PLLA microspheres may find wide applications in biomedical fields.
Super junction LDMOS with step field oxide layer
Authors: Cao Zhen , Duan Baoxing , Yuan Xiaoning , Yuan Song , Yang Yintang
Published: July 2016

A novel step‐oxide super junction‐lateral double‐diffused metal–oxide–semiconductor field‐effect transistor (SOSJ‐LDMOS) structure is proposed and optimised which allows the high breakdown voltage (BV) and low‐specific on‐resistance (Ron, sp). The proposed structure overcomes the effect of thick field oxide formed by shallow trench isolation process in conventional buffer layer SJ‐LDMOS (N ‐buffered SJ‐LDMOS), effectively enhancing the performance of the SJ‐LDMOS. Thanks to the SO layer, a new electric field peak has been introduced in the surface electric field distribution, which makes the lateral surface electric field uniform in the off‐state. Moreover, due to the thinner oxide layer, in the on‐state the majority of electron current is accumulated near the top surface under the field plate and the thinner oxide layer also provides a wider current flowing path. In the virtue of integrated systems engineering (ISE) simulation, not only has the BV of SOSJ‐LDMOS been increased, but also the Ron, sp has been reduced simultaneously compared with the N ‐buffered SJ‐LDMOS in the same drift length. In addition, when SOSJ‐LDMOS and N ‐buffered LDMOS are at the same BV, the Ron, sp of SOSJ‐LDMOS is decreased by 26.3–38.9%, compared with the N ‐buffer SJ‐LDMOS.
Genetics Studies in Idiopathic Focal Epilepsies in Childhood
Authors: Szepetowski Pierre
Published: July 2016

Numerous “epilepsy genes” have been identified in the recent years, thanks to the recent progress in massive parallel sequencing and genome analysis. Among the formerly called “idiopathic” childhood focal epilepsies, a first and major gene responsible for focal epilepsies and epileptic encephalopathies with speech and language dysfunction (the epilepsy–aphasia spectrum, EAS), GRIN2A, has been identified. GRIN2A encodes the GluN2A subunit of N-methyl-D-aspartate receptors, which are gated by the excitatory neurotransmitter glutamate. More than 60 mutations of various types and with various functional consequences in vitro have been reported. Several rare genetic variants that may influence EAS have been reported in a few other genes. The identification of GRIN2A as a first cause of EAS represents a first key point that will help in deciphering the underlying pathophysiology and in understanding the clinical heterogeneity and variability seen in the patients and families.
Errata: Die Zukunft der medizinisch–rehabilitativen Versorgung im Kontext der Multimorbidität – Teil I: Begriffsbestimmung, Versorgungsfragen und Herausforderungen
Authors: Seger W. , Cibis W. , Deventer A. , Grotkamp S. , Lübke N. , Schönle P.-W. , Schmidt-Ohlemann M. , Schubert M.
Published: July 2016

W. Seger, W. Cibis, A. Deventer, S. Grotkamp, N. Lübke, P.-W. Schönle, M. Schubert. Die Zukunft der medizinisch-rehabilitativen
Versorgung im Kontext der Multimorbidität – Teil I: Begriffsbestimmung, Versorgungsfragen und Herausforderungen Künstlerische
Therapeuten im Gesundheitswesen. Gesundheitswesen 2016;

Bei diesem Beitrag fehlte ein Autor und die zugehörige Institutsangabe.
Nachfolgend die ergänzten Autoren und Institute:

Autoren:

W. Seger1, W. Cibis2, A. Deventer3, S. Grotkamp4, N. Lübke5,
P.-W. Schönle6, M. Schmidt-Ohlemann7, M. Schubert2

Institute:

1 MDK Niedersachsen, Hannover
2 Bundesarbeitsgemeinschaft für Rehabilitation (BAR),
Frankfurt
3 Praxis für Physikalische und Rehabilitative Medizin,
Hamburg
4 MDK Niedersachsen, SEG 1, Hannover
5 Kompetenz-Centrum Geriatrie (KCG), Hamburg
6 Maternus Kliniken, Bad Oeynhausen
7 Diakonie Bad Kreuznach, Rehabilitationsklinik, Bad Kreuznach
Explosive synchronization coexists with classical synchronization in the Kuramoto model
Authors: Danziger Michael M. , Moskalenko Olga I. , Kurkin Semen A. , Zhang Xiyun , Havlin Shlomo , Boccaletti Stefano
Published: July 2016

Explosive synchronization has recently been reported in a system of adaptively coupled Kuramoto oscillators, without any conditions on the frequency or degree of the nodes. Here, we find that, in fact, the explosive phase coexists with the standard phase of the Kuramoto oscillators. We determine this by extending the mean-field theory of adaptively coupled oscillators with full coupling to the case with partial coupling of a fraction f. This analysis shows that a metastable region exists for all finite values of f > 0, and therefore explosive synchronization is expected for any perturbation of adaptively coupling added to the standard Kuramoto model. We verify this theory with GPU-accelerated simulations on very large networks (N ∼ 106) and find that, in fact, an explosive transition with hysteresis is observed for all finite couplings. By demonstrating that explosive transitions coexist with standard transitions in the limit of f → 0, we show that this behavior is far more likely to occur naturally than was previously believed.
Magnetic field generation during intense laser channelling in underdense plasma
Authors: Smyth A. G. , Sarri G. , Vranic M. , Amano Y. , Doria D. , Guillaume E. , Habara H. , Heathcote R. , Hicks G. , Najmudin Z. , Nakamura H. , Norreys P. A. , Kar S. , Silva L. O. , Tanaka K. A. , Vieira J. , Borghesi M.
Published: July 2016

Channel formation during the propagation of a high-energy (120 J) and long duration (30 ps) laser pulse through an underdense deuterium plasma has been spatially and temporally resolved via means of a proton imaging technique, with intrinsic resolutions of a few μm and a few ps, respectively. Conclusive proof is provided that strong azimuthally symmetric magnetic fields with a strength of around 0.5 MG are created inside the channel, consistent with the generation of a collimated beam of relativistic electrons. The inferred electron beam characteristics may have implications for the cone-free fast-ignition scheme of inertial confinement fusion.
A review of optimization algorithms for the modeling of proton exchange membrane fuel cell
Authors: Manikandan Tamilarasi , Ramalingam Seyezhai
Published: July 2016

The main aim of this paper is to review different optimization techniques and to describe the importance of the Honey Bee Mating Optimization (HBMO) Algorithm for the modeling of fuel cells. HBMO algorithm is a nature inspired one that simulates the process of real Honey Bee Mating and the natural foraging behavior of honey bee has been discussed. The objective function has been framed for the static modeling of proton exchange membrane fuel cell by considering certain constraints. HBMO is implemented to optimize the appropriate parameter and it is mainly dependent upon the parameter decisions; therefore, it results in improved computation. The proposed HBMO is compared with the conventional algorithms like simulated annealing, pattern search, particle swarm, and genetic algorithm reported in the literature. By using the HBMO technique, the electrical, fuel processor, hydrogen, oxygen, and water response times are analyzed and compared with the other algorithms. The results are validated. The proposed HBMO algorithm surpasses the above mentioned optimizers in terms of accuracy.
Evidence for concerted ring opening and C–Br bond breaking in UV-excited bromocyclopropane
Authors: Pandit Shubhrangshu , Preston Thomas J. , King Simon J. , Vallance Claire , Orr-Ewing Andrew J.
Published: July 2016

Photodissociation of gaseous bromocyclopropane via its A-band continuum has been studied at excitation wavelengths ranging from 230 nm to 267 nm. Velocity-map images of ground-state bromine atoms (Br), spin-orbit excited bromine atoms (Br∗), and C3H5 hydrocarbon radicals reveal the kinetic energies of these various photofragments. Both Br and Br∗ atoms are predominantly generated via repulsive excited electronic states in a prompt photodissociation process in which the hydrocarbon co-fragment is a cyclopropyl radical. However, the images obtained at the mass of the hydrocarbon radical fragment identify a channel with total kinetic energy greater than that deduced from the Br and Br∗ images, and with a kinetic energy distribution that exceeds the energetic limit for Br + cyclopropyl radical products. The velocity-map images of these C3H5 fragments have lower angular anisotropies than measured for Br and Br∗, indicating molecular restructuring during dissociation. The high kinetic energy C3H5 signals are assigned to allyl radicals generated by a minor photochemical pathway which involves concerted C–Br bond dissociation and cyclopropyl ring-opening following single ultraviolet (UV)-photon absorption. Slow photofragments also contribute to the velocity map images obtained at the C3H5 radical mass, but the corresponding slow Br atoms are not observed. These features in the images are attributed to C3H5+ from the photodissociation of the C3H5Br+ molecular cation following two-photon ionization of the parent compound. This assignment is confirmed by 118-nm vacuum ultraviolet ionization studies that prepare the molecular cation in its ground electronic state prior to UV photodissociation.
Three-dimensional wake topology and propulsive performance of low-aspect-ratio pitching-rolling plates
Authors: Li Chengyu , Dong Haibo
Published: July 2016

The wake topology and propulsive performance of low-aspect-ratio plates undergoing a pitching-rolling motion in a uniform stream were numerically investigated by an in-house immersed-boundary-method-based incompressible Navier-Stokes equation solver. A detailed analysis of the vortical structures indicated that the pitching-rolling plate produced double-loop vortices with alternating signs from its trailing edge every half period. These vortices then shed and further evolved into interconnected “double-C”-shaped vortex rings, which eventually formed a bifurcating wake pattern in the downstream. As the wake convected downstream, there was a slight deflection in the spanwise direction to the plate tip, and the contained vortex ring size gradually increased. In addition, the analysis of the propulsive performance indicated that the shedding process of the double-loop vortices led to two peaks in the lift and thrust force production per half cycle. The observation of the double peaks in the force production is in agreement with previous flapping wing studies. Simulations were also used to examine the variations in the wake structures and propulsive performance of the plates over a range of major parameters. The aforementioned vortex structures were found to be quite robust over a range of Strouhal numbers, Reynolds numbers, and plate aspect ratios.
Role of low-energy phonons with mean-free-paths >0.8 μm in heat conduction in silicon
Authors: Jiang Puqing , Lindsay Lucas , Koh Yee Kan
Published: July 2016

Despite recent progress in the first-principles calculations and measurements of phonon mean-free-paths (ℓ), contribution of low-energy phonons to heat conduction in silicon is still inconclusive, as exemplified by the discrepancies as large as 30% between different first-principles calculations. Here, we investigate the contribution of low-energy phonons with ℓ > 0.8 μm by accurately measuring the cross-plane thermal conductivity (Λcross) of crystalline silicon films by time-domain thermoreflectance (TDTR), over a wide range of film thicknesses 1 ≤ hf ≤ 10 μm and temperatures 100 ≤ T ≤ 300 K. We employ a dual-frequency TDTR approach to improve the accuracy of our Λcross measurements. We find from our Λcross measurements that phonons with ℓ > 0.8 μm contribute 53 W m−1 K−1 (37%) to heat conduction in natural Si at 300 K, while phonons with ℓ > 3 μm contribute 523 W m−1 K−1 (61%) at 100 K, >20% lower than first-principles predictions of 68 W m−1 K−1 (47%) and 717 W m−1 K−1 (76%), respectively. Using a relaxation time approximation model, we demonstrate that macroscopic damping (e.g., Akhieser's damping) eliminates the contribution of phonons with mean-free-paths >20 μm at 300 K, which contributes 15 W m−1 K−1 (10%) to calculated heat conduction in Si. Thus, we propose that omission of the macroscopic damping for low-energy phonons in the first-principles calculations could be one of the possible explanations for the observed differences between our measurements and calculations. Our work provides an important benchmark for future measurements and calculations of the distribution of phonon mean-free-paths in crystalline silicon.
Computational study of effect of water finger on ion transport through water-oil interface
Authors: Kikkawa Nobuaki , Wang Lingjian , Morita Akihiro
Published: July 2016

When an ion transports from water to oil through water-oil interface, it accompanies hydrated water molecules and transiently forms a chain of water, called “water finger.” We thoroughly investigated the role of the water finger in chloride ion transport through water-dichloromethane interface by using molecular dynamics technique. We developed a proper coordinate w to describe the water finger structure and calculated the free energy landscape and the friction for the ion transport as a function of ion position z and the water finger coordinate w. It is clearly shown that the formation and break of water finger accompanies an activation barrier for the ion transport, which has been overlooked in the conventional free energy curve along the ion position z. The present analysis of the friction does not support the hypothesis of augmented local friction (reduced local diffusion coefficient) at the interface. These results mean that the experimentally observed rate constants of interfacial ion transfer are reduced from the diffusion-limited one because of the activation barrier associated to the water finger, not the anomalous local diffusion. We also found that the nascent ion just after the break of water finger has excessive hydration water than that in the oil phase.
On relativistic space charge limited current in planar, cylindrical, and spherical diodes
Authors: Greenwood A. D. , Hammond J. F. , Zhang P. , Lau Y. Y.
Published: July 2016

This paper revisits the relativistic limiting current in planar, cylindrical, and spherical diodes, with alternative analytic and numerical treatments which are easy to implement. Convenient, approximate expressions for the limited current are presented for gap voltages up to 10 MV. They are accurate to within 1% for planar diode, and to within 4% for both cylindrical and spherical diode in the range 10−5<rc/ra<500, where ra and rc are, respectively, the anode and cathode radius.
Novel isochronous N-body problems featuring N arbitrary rational coupling constants
Authors: Calogero F.
Published: July 2016

A novel class of N-body problems is identified, with N an arbitrary positive integer (N ≥ 2). These models are characterized by Newtonian (“accelerations equal forces”) equations of motion describing N equal point-particles moving in the complex z-plane. These highly nonlinear equations feature N arbitrary coupling constants, yet they can be solved by algebraic operations and if all the N coupling constants are real and rational the corresponding N-body problem is isochronous: its generic solutions are all completely periodic with an overall period T independent of the initial data (but many solutions feature subperiods T/p with p integer). It is moreover shown that these models are Hamiltonian.
Load-cell based characterization system for a “Violin-Mode” shadow-sensor in advanced LIGO suspensions
Authors: Lockerbie N. A. , Tokmakov K. V.
Published: July 2016

The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which 40 kg test-mass/mirrors are each suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation and a rectangular silicon photodiode detector, which, together, were to bracket the fibre under test. The aim was to detect transverse Violin-Mode resonances in the suspension fibres. Part of the testing procedure involved tensioning a silica fibre sample and translating it transversely through the illuminating NIR beam, so as to measure the DC responsivity of the detection system to fibre displacement. However, an equally important part of the procedure, reported here, was to keep the fibre under test stationary within the beam, whilst trying to detect low-level AC Violin-Mode resonances excited on the fibre, in order to confirm the primary function of the sensor. Therefore, a tensioning system, incorporating a load-cell readout, was built into the test fibre’s holder. The fibre then was excited by a signal generator, audio power amplifier, and distant loudspeaker, and clear resonances were detected. A theory for the expected fundamental resonant frequency as a function of fibre tension was developed and is reported here, and this theory was found to match closely with the detected resonant frequencies as they varied with tension. Consequently, the resonances seen were identified as being proper Violin-Mode fundamental resonances of the fibre, and the operation of the Violin-Mode detection system was validated.
Consistency of multi-time Dirac equations with general interaction potentials
Authors: Deckert Dirk-André , Nickel Lukas
Published: July 2016

In 1932, Dirac proposed a formulation in terms of multi-time wave functions as candidate for relativistic many-particle quantum mechanics. A well-known consistency condition that is necessary for existence of solutions strongly restricts the possible interaction types between the particles. It was conjectured by Petrat and Tumulka that interactions described by multiplication operators are generally excluded by this condition, and they gave a proof of this claim for potentials without spin-coupling. Under suitable assumptions on the differentiability of possible solutions, we show that there are potentials which are admissible, give an explicit example, however, show that none of them fulfills the physically desirable Poincaré invariance. We conclude that in this sense, Dirac’s multi-time formalism does not allow to model interaction by multiplication operators, and briefly point out several promising approaches to interacting models one can instead pursue.
Accurate measurements of cross-plane thermal conductivity of thin films by dual-frequency time-domain thermoreflectance (TDTR)
Authors: Jiang Puqing , Huang Bin , Koh Yee Kan
Published: July 2016

Accurate measurements of the cross-plane thermal conductivity Λcross of a high-thermal-conductivity thin film on a low-thermal-conductivity (Λs) substrate (e.g., Λcross/Λs > 20) are challenging, due to the low thermal resistance of the thin film compared with that of the substrate. In principle, Λcross could be measured by time-domain thermoreflectance (TDTR), using a high modulation frequency fh and a large laser spot size. However, with one TDTR measurement at fh, the uncertainty of the TDTR measurement is usually high due to low sensitivity of TDTR signals to Λcross and high sensitivity to the thickness hAl of Al transducer deposited on the sample for TDTR measurements. We observe that in most TDTR measurements, the sensitivity to hAl only depends weakly on the modulation frequency f. Thus, we performed an additional TDTR measurement at a low modulation frequency f0, such that the sensitivity to hAl is comparable but the sensitivity to Λcross is near zero. We then analyze the ratio of the TDTR signals at fh to that at f0, and thus significantly improve the accuracy of our Λcross measurements. As a demonstration of the dual-frequency approach, we measured the cross-plane thermal conductivity of a 400-nm-thick nickel-iron alloy film and a 3-μm-thick Cu film, both with an accuracy of ∼10%. The dual-frequency TDTR approach is useful for future studies of thin films.
Thermal conductivity versus depth profiling of inhomogeneous materials using the hot disc technique
Authors: Sizov A. , Cederkrantz D. , Salmi L. , Rosén A. , Jacobson L. , Gustafsson S. E. , Gustavsson M.
Published: July 2016

Transient measurements of thermal conductivity are performed with hot disc sensors on samples having a thermal conductivity variation adjacent to the sample surface. A modified computational approach is introduced, which provides a method of connecting the time-variable to a corresponding depth-position. This allows highly approximate—yet reproducible—estimations of the thermal conductivity vs. depth. Tests are made on samples incorporating different degrees of sharp structural defects at a certain depth position inside a sample. The proposed methodology opens up new possibilities to perform non-destructive testing; for instance, verifying thermal conductivity homogeneity in a sample, or estimating the thickness of a deviating zone near the sample surface (such as a skin tumor), or testing for presence of other defects.
Topotaxial growth of α-Fe2O3 nanowires on iron substrate in thermal annealing method
Authors: Srivastava Himanshu , Srivastava A. K. , Babu Mahendra , Rai Sanjay , Ganguli Tapas
Published: July 2016

A detail cross-sectional transmission electron microscopy of as-grown α-Fe2O3 nanowire sample, synthesized on iron substrate by thermal annealing method, was carried out to understand the mechanism of growth in this system. Iron undergoes sequential oxidation to form a layered structure of Fe/FeO/Fe3O4/α-Fe2O3. α-Fe2O3 nanowires grow on to the top of α-Fe2O3 layer. It was found that subsequent oxide layers grow topotaxially on the grains of iron, which results in a direct orientation relationship between the α-Fe2O3 nanowire and the parent grain of iron. The results also showed that the grains of α-Fe2O3 layer, which were uniquely oriented in [110] direction, undergo highly anisotropic growth to form the nanowire. This anisotropic growth occurs at a twin interface, given by (−11−1), in the α-Fe2O3 layer. It was concluded that the growth at twin interface could be the main driving factor for such anisotropic growth. These observations are not only helpful in understanding the growth mechanism of α-Fe2O3 nanowires, but it also demonstrates a way of patterning the nanowires by controlling the texture of iron substrate.
Suppression of photo-bias induced instability for amorphous indium tungsten oxide thin film transistors with bi-layer structure
Authors: Liu Po-Tsun , Chang Chih-Hsiang , Chang Chih-Jui
Published: July 2016

This study investigates the instability induced by bias temperature illumination stress (NBTIS) for an amorphous indium-tungsten-oxide thin film transistor (a-IWO TFT) with SiO2 backchannel passivation layer (BPL). It is found that this electrical degradation phenomenon can be attributed to the generation of defect states during the BPL process, which deteriorates the photo-bias stability of a-IWO TFTs. A method proposed by adding an oxygen-rich a-IWO thin film upon the a-IWO active channel layer could effectively suppress the plasma damage to channel layer during BPL deposition process. The bi-layer a-IWO TFT structure with an oxygen-rich back channel exhibits superior electrical reliability of device under NBTIS.
Striped gold nanoparticles: New insights from molecular dynamics simulations
Authors: Velachi Vasumathi , Bhandary Debdip , Singh Jayant K. , Cordeiro M. Natália D. S.
Published: July 2016

Recent simulations have improved our knowledge of the molecular-level structure and hydration properties of mixed self-assembled monolayers (SAMs) with equal and unequal alkyl thiols at three different arrangements, namely, random, patchy, and Janus. In our previous work [V. Vasumathi et al., J. Phys. Chem. C 119, 3199–3209 (2015)], we showed that the bending of longer thiols over shorter ones clearly depends on the thiols’ arrangements and chemical nature of their terminal groups. In addition, such a thiol bending revealed to have a strong impact on the structural and hydration properties of SAMs coated on gold nanoparticles (AuNPs). In this paper, we extend our previous atomistic simulation study to investigate the bending of longer thiols by increasing the stripe thickness of mixed SAMs of equal and unequal lengths coated on AuNPs. We study also the effect of stripe thickness on the structural morphology and hydration of the coated SAMs. Our results show that the structural and hydration properties of SAMs are affected by the stripe thickness for mixtures of alkyl thiols with unequal chain length but not for equal length. Hence, the stability of the stripe configuration depends on the alkyl’s chain length, the length difference between the thiol mixtures, and solvent properties.
On the electron drift velocity in plasma devices with E×B drift
Authors: Chapurin O. , Smolyakov A.
Published: July 2016

The structure and various components of the electron drift velocity are discussed in application to plasma discharges with the E×B drift. In high density plasmas, the contribution of the diamagnetic drift can be of the same order magnitude as the E×B drift. It is pointed out that curvature and gradient drifts associated with magnetic field inhomogeneities manifest themselves via the electron pressure anisotropy. Estimates show that the components of the diamagnetic drift related to the electron pressure anisotropy and magnetic field gradients can be important for the parameters of modern magnetrons and Hall thrusters. Similar additional terms appear in the momentum balance as mirror forces which may affect the distribution of the electrostatic potential in Hall devices.
A novel method for the measurement of the von Neumann spike in detonating high explosives
Authors: Sollier A. , Bouyer V. , Hébert P. , Doucet M.
Published: July 2016

We present detonation wave profiles measured in T2 (97 wt. % TATB) and TX1 (52 wt. % TATB and 45 wt. % HMX) high explosives. The experiments consisted in initiating a detonation wave in a 15 mm diameter cylinder of explosive using an explosive wire detonator and an explosive booster. Free surface velocity wave profiles were measured at the explosive/air interface using a Photon Doppler Velocimetry system. We demonstrate that a comparison of these free surface wave profiles with those measured at explosive/window interfaces in similar conditions allows to bracket the von Neumann spike in a narrow range. For T2, our measurements show that the spike pressure lies between 35.9 and 40.1 GPa, whereas for TX1, it lies between 42.3 and 47.0 GPa. The numerical simulations performed in support to these measurements show that they can be used to calibrate reactive burn models and also to check the accuracy of the detonation products equation of state at low pressure.
Dynamic rating of a service power cable subject to intermittent loading
Authors: Xiao Jixue , Ran Li , Taylor Phil
Published: July 2016

This paper presents a model based method to estimate the internal core temperature of a service power cable subject to intermittent loading. The estimation is then used to control the loading so that the cable can be safely utilized to the limit of its capability. The method considers the temperature dependence of the cable resistance and is insensitive to the variations in the environment. The model is backed by laboratory experiment and the effectiveness of the dynamic rating approach is evaluated by simulation.
Multi-walled carbon nanotubes with rectangular or square cross-section
Authors: Mizutani Kanako , Kohno Hideo
Published: July 2016

Multi-walled carbon nanotubes with rectangular or square cross-section are formed. The nanotubes are about 50–200 nm in width, and their walls are around 5–30 nm thick. It is very likely that the rectangular cross-section is shaped simultaneously when nanotubes are formed from catalyst Fe nanoparticles during chemical vapor deposition process, and the shape is stabilized by the bonding between adjoining graphene layers in the multi-walled structure.
Effect of functionality on unentangled star polymers at equilibrium and under shear flow
Authors: Xu Xiaolei , Chen Jizhong
Published: July 2016

The properties of unentangled star polymers with arm length Nf = 20 beads and functionality f (3 ≤ f ≤ 60) are investigated at equilibrium and under shear flow by coarse-grained molecular dynamics simulations. At equilibrium, the star polymer shows a crossover from a linear, freely penetrable, extremely soft object to a spherical, slightly hard object with an impenetrable center with increasing f. The results confirm that the arm relaxation is essentially independent of f and stars of large f form a liquid-like structure. In shear flow, the polymer deformation and alignment are calculated as well as the shear-induced rotational dynamics as function of shear rate. These properties are found to exhibit qualitative changes at an f-independent shear rate, γṗ, which is a consequence of competition between chain relaxation and imposed flow. Shear thinning is characterized by shear viscosity and normal stress differences. With increasing f, the critical shear rate for the onset of shear thinning decreases from γṗ for f = 3 to a smaller value. Our results also show that shear thinning of stars of large f arise from the collapse of liquid-like structures at low shear rates (γ̇≪γṗ), where chains have no deformation; at high shear rates (γ̇≫γṗ), shear thinning is mainly attributed to the chain stretching and orientation as linear polymers.
Magnetic nanoparticles for enhancing the effectiveness of ultrasonic hyperthermia
Authors: Józefczak A. , Kaczmarek K. , Hornowski T. , Kubovčíková M. , Rozynek Z. , Timko M. , Skumiel A.
Published: July 2016

Ultrasonic hyperthermia is a method of cancer treatment in which tumors are exposed to an elevated cytotoxic temperature using ultrasound (US). In conventional ultrasonic hyperthermia, the ultrasound-induced heating in the tumor is achieved through the absorption of wave energy. However, to obtain appropriate temperature in reasonable time, high US intensities, which can have a negative impact on healthy tissues, are required. The effectiveness of US for medical purposes can be significantly improved by using the so-called sonosensitizers, which can enhance the thermal effect of US on the tissue by increasing US absorption. One possible candidate for such sonosensitizers is magnetic nanoparticles with mean sizes of 10–300 nm, which can be efficiently heated because of additional attenuation and scattering of US. Additionally, magnetic nanoparticles are able to produce heat in the alternating magnetic field (magnetic hyperthermia). The synergetic application of ultrasonic and magnetic hyperthermia can lead to a promising treatment modality.