bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyperoxaluria leads to dysbiosis and drives selective enrichment of oxalate metabolizing bacterial species in recurrent kidney stone endures
Authors: Suryavanshi Mangesh V. , Bhute Shrikant S. , Jadhav Swapnil D. , Bhatia Manish S. , Gune Rahul P. , Shouche Yogesh S.
Published: October 2016

Hyperoxaluria due to endogenously synthesized and exogenously ingested oxalates is a leading cause of recurrent oxalate stone formations. Even though, humans largely rely on gut microbiota for oxalate homeostasis, hyperoxaluria associated gut microbiota features remain largely unknown. Based on 16S rRNA gene amplicons, targeted metagenomic sequencing of formyl-CoA transferase (frc) gene and qPCR assay, we demonstrate a selective enrichment of Oxalate Metabolizing Bacterial Species (OMBS) in hyperoxaluria condition. Interestingly, higher than usual concentration of oxalate was found inhibitory to many gut microbes, including Oxalobacter formigenes, a well-characterized OMBS. In addition a concomitant enrichment of acid tolerant pathobionts in recurrent stone sufferers is observed. Further, specific enzymes participating in oxalate metabolism are found augmented in stone endures. Additionally, hyperoxaluria driven dysbiosis was found to be associated with oxalate content, stone episodes and colonization pattern of Oxalobacter formigenes. Thus, we rationalize the first in-depth surveillance of OMBS in the human gut and their association with hyperoxaluria. Our findings can be utilized in the treatment of hyperoxaluria associated recurrent stone episodes.
Low viscosity and high attenuation in MgSiO3 post-perovskite inferred from atomic-scale calculations
Authors: Goryaeva Alexandra M. , Carrez Philippe , Cordier Patrick
Published: October 2016

This work represents a numerical study of the thermal activation for dislocation glide of the [100](010) slip system in MgSiO3 post-perovskite (Mg-ppv) at 120 GPa. We propose an approach based on a one-dimensional line tension model in conjunction with atomic-scale calculations. In this model, the key parameters, namely, the line tension and the Peierls barrier, are obtained from density functional theory calculations. We find a Peierls stress σp = 2.1 GPa and a line tension Γ = 9.2 eV/Å, which lead to a kink-pair enthalpy (under zero stress) of 2.69 eV. These values confirm that this slip system bears a very low lattice friction because it vanishes for temperatures above approximately 500 K under mantle conditions. In the Earth’s mantle, high-pressure Mg-ppv silicate is thus expected to become as ductile as ferropericlase. These results confirm the hypothesis of a weak layer in the D″ layer where Mg-ppv is present. Easy glide along [100](010) suggests strong preferred orientations with (010) planes aligned. Highly mobile [100] dislocations are also likely to respond to stresses related to seismic waves, leading to energy dissipation and strong attenuation.
Identification of doublesex alleles associated with the female-limited Batesian mimicry polymorphism in Papilio memnon
Authors: Komata Shinya , Lin Chung-Ping , Iijima Takuro , Fujiwara Haruhiko , Sota Teiji
Published: October 2016

The female-limited Batesian mimicry polymorphism in Papilio butterflies is an intriguing system for investigating the mechanism of maintenance of genetic polymorphisms. In Papilio polytes, an autosomal region encompassing the sex-determinant gene doublesex controls female-limited mimicry polymorphism. In the closely related species P. memnon, which also exhibits female-limited Batesian mimicry polymorphism, we identified two allelic sequences of the doublesex gene that corresponded exactly with the mimetic and non-mimetic female phenotypes. Thus, the genetic basis of the mimicry polymorphism in P. memnon is similar to that in P. polytes. However, the mimetic and non-mimetic alleles of the two species were not identical, and the divergence of alleles occurred independently in P. memnon and P. polytes. Different mutation-selection processes may have resulted in the convergent patterns of mimicry polymorphism in these Papilio butterflies.
Functional value of elytra under various stresses in the red flour beetle, Tribolium castaneum
Authors: Linz David M. , Hu Alan W. , Sitvarin Michael I. , Tomoyasu Yoshinori
Published: October 2016

Coleoptera (beetles) is a massively successful order of insects, distinguished by their evolutionarily modified forewings called elytra. These structures are often presumed to have been a major driving force for the successful radiation of this taxon, by providing beetles with protection against a variety of harsh environmental factors. However, few studies have directly demonstrated the functional significance of the elytra against diverse environmental challenges. Here, we sought to empirically test the function of the elytra using Tribolium castaneum (the red flour beetle) as a model. We tested four categories of stress on the beetles: physical damage to hindwings, predation, desiccation, and cold shock. We found that, in all categories, the presence of elytra conferred a significant advantage compared to those beetles with their elytra experimentally removed. This work provides compelling quantitative evidence supporting the importance of beetle forewings in tolerating a variety of environmental stresses, and gives insight into how the evolution of elytra have facilitated the remarkable success of beetle radiation.
Electrochemical noise and impedance of Au electrode/electrolyte interfaces enabling extracellular detection of glioma cell populations
Authors: Rocha Paulo R. F. , Schlett Paul , Kintzel Ulrike , Mailänder Volker , Vandamme Lode K. J. , Zeck Gunther , Gomes Henrique L. , Biscarini Fabio , de Leeuw Dago M.
Published: October 2016

Microelectrode arrays (MEA) record extracellular local field potentials of cells adhered to the electrodes. A disadvantage is the limited signal-to-noise ratio. The state-of-the-art background noise level is about 10 μVpp. Furthermore, in MEAs low frequency events are filtered out. Here, we quantitatively analyze Au electrode/electrolyte interfaces with impedance spectroscopy and noise measurements. The equivalent circuit is the charge transfer resistance in parallel with a constant phase element that describes the double layer capacitance, in series with a spreading resistance. This equivalent circuit leads to a Maxwell-Wagner relaxation frequency, the value of which is determined as a function of electrode area and molarity of an aqueous KCl electrolyte solution. The electrochemical voltage and current noise is measured as a function of electrode area and frequency and follow unambiguously from the measured impedance. By using large area electrodes the noise floor can be as low as 0.3 μVpp. The resulting high sensitivity is demonstrated by the extracellular detection of C6 glioma cell populations. Their minute electrical activity can be clearly detected at a frequency below about 10 Hz, which shows that the methodology can be used to monitor slow cooperative biological signals in cell populations.
The genetic map of goldfish (Carassius auratus) provided insights to the divergent genome evolutions in the Cyprinidae family
Authors: Kuang You-Yi , Zheng Xian-Hu , Li Chun-Yan , Li Xiao-Min , Cao Ding-Chen , Tong Guang-Xiang , Lv Wei-Hua , Xu Wei , Zhou Yi , Zhang Xiao-Feng , Sun Zhi-Peng , Mahboob Shahid , Al-Ghanim Khalid A. , Li Jiong-Tang , Sun Xiao-Wen
Published: October 2016

A high-density linkage map of goldfish (Carassius auratus) was constructed using RNA-sequencing. This map consists of 50 linkage groups with 8,521 SNP markers and an average resolution of 0.62 cM. Approximately 84% of markers are in protein-coding genes orthologous to zebrafish proteins. We performed comparative genome analysis between zebrafish and medaka, common carp, grass carp, and goldfish to study the genome evolution events in the Cyprinidae family. The comparison revealed large synteny blocks among Cyprinidae fish and we hypothesized that the Cyprinidae ancestor undergone many inter-chromosome rearrangements after speciation from teleost ancestor. The study also showed that goldfish genome had one more round of whole genome duplication (WGD) than zebrafish. Our results illustrated that most goldfish markers were orthologous to genes in common carp, which had four rounds of WGD. Growth-related regions and genes were identified by QTL analysis and association study. Function annotations of the associated genes suggested that they might regulate development and growth in goldfish. This first genetic map enables us to study the goldfish genome evolution and provides an important resource for selective breeding of goldfish.
Bst1 is required for Candida albicans infecting host via facilitating cell wall anchorage of Glycosylphosphatidyl inositol anchored proteins
Authors: Liu Wei , Zou Zui , Huang Xin , Shen Hui , He Li Juan , Chen Si Min , Li Li Ping , Yan Lan , Zhang Shi Qun , Zhang Jun Dong , Xu Zheng , Xu Guo Tong , An Mao Mao , Jiang Yuan Ying
Published: October 2016

Glycosylphosphatidyl inositol anchored proteins (GPI-APs) on fungal cell wall are essential for invasive infections. While the function of inositol deacylation of GPI-APs in mammalian cells has been previously characterized the impact of inositol deacylation in fungi and implications to host infection remains largely unexplored. Herein we describe our identification of BST1, an inositol deacylase of GPI-Aps in Candida albicans, was critical for GPI-APs cell wall attachment and host infection. BST1-deficient C. albicans (bst1Δ/Δ) was associated with severely impaired cell wall anchorage of GPI-APs and subsequen unmasked β-(1,3)-glucan. Consistent with the aberrant cell wall structures, bst1Δ/Δ strain did not display an invasive ability and could be recognized more efficiently by host immune systems. Moreover, BST1 null mutants or those expressing Bst1 variants did not display inositol deacylation activity and exhibited severely attenuated virulence and reduced organic colonization in a murine systemic candidiasis model. Thus, Bst1 can facilitate cell wall anchorage of GPI-APs in C. albicans by inositol deacylation, and is critical for host invasion and immune escape.
Rapid and safe ASAP acquisition with EXACT NMR
Authors: Ndukwe I. E. , Shchukina A. , Kazimierczuk K. , Butts C. P.
Published: October 2016

EXACT acquisition allows the fast and safer acquisition of ASAP 2D NMR experiments in just a few seconds.
A light-up imaging protocol for neutral pH-enhanced fluorescence detection of lysosomal neuraminidase activity in living cells
Authors: Bao Lei , Ding Lin , Hui Jingjing , Ju Huangxian
Published: October 2016

A lysosome-accessing nanoprobe was designed to deliver a Lyso-Neu-specific substrate into lysosomes for neutral pH-enhanced fluorescence detection of Lyso-Neu activity.
Strong shear-driven large scale formation of hybrid shish-kebab in carbon nanofiber reinforced polyethylene composites during the melt second flow
Authors: Xia Xiao-Chao , Yang Wei , Liu Zheng-Ying , Zhang Rui-Yan , Xie Dan-Dan , Yang Ming-Bo
Published: October 2016

A strong shear drives the large scale formation of hybrid shish-kebab in carbon nanofiber reinforced polyethylene composites during the melt second flow.
A comparative study of Ni–Mn layered double hydroxide/carbon composites with different morphologies for supercapacitors
Authors: Li M. , Liu F. , Zhang X. B. , Cheng J. P.
Published: October 2016

A variety of carbon materials varying from 0D to 2D, i.e. 0D nanoparticles, 1D carbon nanotubes (CNTs) and 2D reduced graphene oxide (rGO) are selected to in situ combine with Ni–Mn layered double hydroxide (LDH) to prepare electrode materials for supercapacitors.
Tunneling chemical exchange reaction D + HD → D2 + H in solid HD and D2 at temperatures below 1 K
Authors: Sheludiakov S. , Ahokas J. , Järvinen J. , Zvezdov D. , Lehtonen L. , Vainio O. , Vasiliev S. , Lee D. M. , Khmelenko V. V.
Published: October 2016

The rates of the isotopic exchange reaction D + HD → D2 + H were measured in solid HD and D2:0.23%HD in a temperature range of 0.13–1.5 K.
An ab initio anharmonic approach to study vibrational spectra of small ammonia clusters
Authors: Ho Kun-Lin , Lee Lo-Yun , Katada Marusu , Fujii Asuka , Kuo Jer-Lai
Published: October 2016

Fermi resonance between the N–H stretching (ν1 and ν3) and the overtone of N–H bending (2ν4) in ammonia has hindered the interpretation and assignments of experimental spectra of small ammonia clusters.
Formation of the prebiotic molecule NH2CHO on astronomical amorphous solid water surfaces: accurate tunneling rate calculations
Authors: Song Lei , Kästner Johannes
Published: October 2016

Investigating how formamide forms in the interstellar medium is a hot topic in astrochemistry, which can contribute to our understanding of the origin of life on Earth.
Experimental, theoretical and computational investigation of the inelastic neutron scattering spectrum of a homonuclear diatomic molecule in a nearly spherical trap: H2@C60
Authors: Mamone Salvatore , Jiménez-Ruiz Mónica , Johnson Mark R. , Rols Stéphane , Horsewill Anthony J.
Published: October 2016

In this paper we report a methodology for calculating the inelastic neutron scattering spectrum of homonuclear diatomic molecules confined within nano-cavities of spherical symmetry.
Ion induced dewetting of Au–Si on a SiO2 surface: composite nanodot evolution and wettability transition
Authors: Datta D. P. , Siva V. , Varma S. , Kanjilal D. , Sahoo P. K.
Published: October 2016

Ion beam dewetting leads to self-organized evolution of an Au–Si composite nanodot array on SiO2 with controllable wettability.
An accurate multi-channel multi-reference full-dimensional global potential energy surface for the lowest triplet state of H2O2
Authors: Li Jun , Dawes Richard , Guo Hua
Published: October 2016

A full dimensional potential energy surface for the lowest triplet state of H2O2was developed at the MRCI-F12 level.
The separation mechanism of Am(iii) from Eu(iii) by diglycolamide and nitrilotriacetamide extraction reagents using DFT calculations
Authors: Kaneko Masashi , Watanabe Masayuki , Matsumura Tatsuro
Published: October 2016

DFT calculated stabilization energies reproduced the experimental separation behavior of Am3+ from Eu3+ using diglycolamide and nitrilotriacetamide ligands.
A cooperative pathway for water activation using a bimetallic Pt0–CuI system
Authors: Jamali S. , Abedanzadeh S. , Khaledi N. K. , Samouei H. , Hendi Z. , Zacchini S. , Kia R. , Shahsavari H. R.
Published: October 2016

Cooperative activation of a water molecule with a bimetallic platinum(0)–copper(i) system results in formation of copper(i) hydroxide and a platinum hydride species. The latter is stable under acidic and neutral conditions but undergoes cyclometalation in the presence of pyridine.
The flux growth of single-crystalline CoTiO3 polyhedral particles and improved visible-light photocatalytic activity of heterostructured CoTiO3/g-C3N4 composites
Authors: Wang Qiang , Guo Qingjun , Wang Leping , Li Bing
Published: October 2016

Novel CoTiO3/g-C3N4 heterostructures with improved photocatalytic activity were successfully synthesized by a facile in situ growth route with the flux-grown CoTiO3 polyhedral crystals serving as an efficient visible-light sensitizer.
QSAR models of human data can enrich or replace LLNA testing for human skin sensitization
Authors: Alves Vinicius M. , Capuzzi Stephen J. , Muratov Eugene N. , Braga Rodolpho C. , Thornton Thomas E. , Fourches Denis , Strickland Judy , Kleinstreuer Nicole , Andrade Carolina H. , Tropsha Alexander
Published: October 2016

An example of structural transformation of human skin sensitizers into various non-sensitizers based on interpretation of QSAR models.
Compositional depth profiling of diamond-like carbon layers by glow discharge optical emission spectroscopy
Authors: Schubert C. , Hoffmann V. , Kümmel A. , Sinn J. , Härtel M. , Reuther A. , Thomalla M. , Gemming T. , Eckert J. , Leyens C.
Published: October 2016

This article describes the compositional depth profiling (CDP) of diamond-like carbon (DLC) layers by Glow Discharge-Optical Emission Spectrometry (GD-OES).
A fluidic circuit based, high-efficiency and large-scale single cell trap
Authors: Mi Lu , Huang Liang , Li Junxiang , Xu Guoqiang , Wu Qiong , Wang Wenhui
Published: October 2016

Equivalent resistive electric circuit inspired, deterministic single cell trap with high efficiency and flexibility for large scale cell patterning.
Luminescent CuI thiocyanate complexes based on tris(2-pyridyl)phosphine and its oxide: from mono-, di- and trinuclear species to coordination polymers
Authors: Artem’ev Alexander V. , Doronina Evgeniya P. , Rakhmanova Marianna I. , Sutyrina Anastasiya O. , Bagryanskaya Irina Yu. , Tolstoy Peter M. , Gushchin Artem L. , Mazur Anton S. , Gusarova Nina K. , Trofimov Boris A.
Published: October 2016

The synthesis, structural and photophysical properties of the novel family of Cu(i) thiocyanate complexes supported by tripodal ligands are presented.
Synthesis and photophysics of extended π-conjugated systems of substituted 10-aryl-pyrenoimidazoles
Authors: Karthik Shanmugam , Ajantha Joseph , Nagaraja C. M. , Easwaramoorthi Shanmugam , Gandhi Thirumanavelan
Published: October 2016

Oxidative annulation of 10-aryl-pyrenoimidazoles with diphenylacetylene has been accomplished by using Ru catalyst. Resultant π-extended systems show intense fluorescence both in solution and solid states.
Poly(ionic liquid)s with controlled architectures and their use in the making of ionogels with high conductivity and tunable rheological properties
Authors: Srour H. , Leocmach M. , Maffeis V. , Ghogia A. C. , Denis-Quanquin S. , Taberlet N. , Manneville S. , Andraud C. , Bucher C. , Monnereau C.
Published: October 2016

We describe the preparation as well as the electrochemical and mechanical properties of a series of novel well-defined poly(ionic liquids) (PILs) featuring a finely tuned cross-linking ratio.
BODIPY-based conjugated microporous polymers as reusable heterogeneous photosensitisers in a photochemical flow reactor
Authors: Tobin J. M. , Liu J. , Hayes H. , Demleitner M. , Ellis D. , Arrighi V. , Xu Z. , Vilela F.
Published: October 2016

Production of singlet oxygen at 530 nm in a flow reactor using novel BODIPY-based polymers as heterogeneous photosensitisers.
Molecular dynamics study on structure evolution of monocarboxylic acid intercalated layered double hydroxides
Authors: Tong Xuhang , Choi Phillip , Li Shuang , Shi Yixiang , Zhang Hao
Published: October 2016

Classical molecular dynamics simulations were conducted to investigate the atomistic structures of monocarboxylic acid intercalated LDHs – a promising candidate for solid sorbents for carbon dioxide capture at intermediate temperatures.
A DFT study on the interaction between 5-fluorouracil and B12N12 nanocluster
Authors: Javan Masoud Bezi , Soltani Alireza , Azmoodeh Zivar , Abdolahi Nafiseh , Gholami Niloofar
Published: October 2016

The most stable interaction of 5-FU drug molecule from its nitrogen head (di-enol form) over B12N12 nano-cage is determined using density functional theory calculations.
Improved corrosion resistance by forming multilayers over a copper surface by electrodeposition followed by a novel sol–gel coating method
Authors: Balaji J. , Sethuraman M. G.
Published: October 2016

A nickel coating was easily electrodeposited from nickel ammonium sulfate, after which surface modification was performed by subsequent immersion into the sol–gel mixture of 3-aminopropyltriethoxysilane, tetraethoxysilane and lauric acid.
Fabrication of superhydrophobic fiber fabric/epoxy composites coating on aluminum substrate with long-lived wear resistance
Authors: Wang Huaiyuan , Wang Rui , Tao Ruifeng , Zhu Yixing , Lv Chongjiang , Zhu Yanji
Published: October 2016

A superhydrophobic coating with long-lived wear resistance was successfully prepared by integrating the hydrophobization of cotton fiber fabric and the curing of epoxy composites.
Efficient light trapping of quasi-inverted nanopyramids in ultrathin c-Si through a cost-effective wet chemical method
Authors: Tang Quntao , Shen Honglie , Gao Kai , Yao Hanyu , Jiang Ye , Zheng Chaofan , Pu Tian , Li Yufang , Liu Youwen , Zhang Lei
Published: October 2016

Double-sided quasi-inverted nanopyramids (QIP) is proposed to realize an over 4.2-fold reduction in silicon material usage with the average absorptance value almost the same.
Nanostructured layered Sn3O4 for hydrogen production and dye degradation under sunlight
Authors: Balgude S. D. , Sethi Y. A. , Kale B. B. , Munirathnam N. R. , Amalnerkar D. P. , Adhyapak P. V.
Published: October 2016

Nanostructured layered Sn3O4 nanoplatelets were synthesized via a facile hydrothermal method.
Cytotoxicity and imaging studies of β-NaGdF4:Yb3+Er3+@PEG-Mo nanorods
Authors: Woźniak Anna , Noculak Agnieszka , Gapiński Jacek , Kociolek Daria , Boś-Liedke Agnieszka , Zalewski Tomasz , Grześkowiak Bartosz F. , Kołodziejczak Anna , Jurga Stefan , Banski Mateusz , Misiewicz Jan , Podhorodecki Artur
Published: October 2016

Multimodal imaging based on nanostructures has become a subject of interest for numerous biomedical laboratories.
Mild synthesis of mercaptonitriles from vinyl nitriles and their cyclization reactions
Authors: Caspari Philip , Nüesch Frank A. , Neels Antonia , Opris Dorina M.
Published: October 2016

Thiol–ene addition of thioacetic acid A is widely used in the synthesis of thiols from vinyl precursors, but so far has not been conducted on non-conjugated vinyl nitriles.
Enhancement of the physicochemical properties of [Pt(dien)(nucleobase)]2+ for HIVNCp7 targeting
Authors: Tsotsoros S. D. , Lutz P. B. , Daniel A. G. , Peterson E. J. , de Paiva R. E. F. , Rivera E. , Qu Y. , Bayse C. A. , Farrell N. P.
Published: October 2016

Building from tryptophan to the tryptophan-containing HIV Nucleocapsid 7 (HIVNCp7) protein we combine biophysical and computational studies to enhance stacking interactions of purines through platination. The incorporation into a weak Lewis acid electrophile, [Pt(dien)(Nucleobase)]2+ may lead to disruption of the HIVNCp7-RNA interaction.
Propeller-shaped small molecule acceptors containing a 9,9′-spirobifluorene core with imide-linked perylene diimides for non-fullerene organic solar cells
Authors: Song Kyu Chan , Singh Ranbir , Lee Jaewon , Sin Dong Hun , Lee Hansol , Cho Kilwon
Published: October 2016

Novel propeller-shaped non-fullerene small molecule acceptors with imide-linked perylene diimides on a 9,9′-spirobi[9H-fluorene] core, namely SF-iPDI2 and SF-iPDI4, were designed and synthesized for organic solar cells.
Enhancing perceptrons with contrastive biclusters
Authors: Coelho A.L.V. , de França F.O.
Published: October 2016

An enhanced perceptron model, referred to as BicNeuron (BN), which is based on the novel concept of contrastive biclusters is investigated. According to this viewpoint, a coherent bicluster (i.e. a subset of data patterns showing high similarity across a particular subset of features) belonging to one class is required to show high discrimination from the nearest patterns of the other class when projected on the same feature set. On each local subspace associated with a different pair of contrastive biclusters a perceptron is induced and the model with highest area under the receiver operating characteristic curve value is selected as the final classifier. Experiments involving the discrimination of epileptic and non‐epileptic electroencephalogram (EEG) signals show that the BN approach can be very useful, prevailing significantly on standard and kernel perceptrons in terms of classification accuracy.
Implementation and broadband calibration of a multichannel vector modulator module
Authors: Wang Chao , Miao Jungang
Published: October 2016

The design, implementation, measurements, and broadband calibration of a 16‐channel vector modulator (VM) module covering 1.5–2.4GHz band are presented in this study. Since the practical realisation of the VM suffers from the effects of non‐ideal characteristics, a broadband calibration technique is adopted which greatly improves the transmission of phase and amplitude accuracy of the VM over a wide frequency range. The measurement results of the calibrated VM are given to show the high calibration accuracy and efficiency of the proposed technique.
Designing disturbance observer for non‐linear systems – a Hirschorn inverse approach
Authors: Dasgupta Sudeshna , Sadhu Smita , Ghoshal Tapan Kumar
Published: October 2016

Disturbance observers (DOBs) are increasingly being suggested as a necessary component in active anti‐disturbance control. Although the structure and design pragmatics of DOBs for linear systems are well known, very few publications deal with DOB for non‐linear systems. A new method for designing DOBs for non‐linear systems has been proposed. Instead of the usual observer gain based approach, the proposed approach employs Lie derivative and Hirschorn inverse. The algorithm for the proposed DOB, its applicability, structure, along with its block diagram have been presented and discussed. Performance of the proposed DOB has been evaluated using highly non‐linear chemical processes. Additionally, the performance is compared with that for a well‐known DOB to demonstrate the superiority of the proposed DOB.
Silver nanoparticles for melamine detection in milk based on transmitted light intensity
Authors: Ramalingam Kaarthika , Devasena Thiyagarajan , Senthil Bakthavatchalam , Kalpana Ramakrishnan , Jayavel Ramasamy
Published: October 2016

Melamine (C3H6N6) is a commercially synthesised organic compound which is illegally added to milk during processing to boost the apparent protein content. Melamine cannot be metabolised by the body and forms insoluble crystals which causes tissue damage and renal dysfunction. Hence, there is a need to develop a rapid and reliable method for melamine detection. Attempted here is to develop a simple procedure to detect melamine in milk using silver nanoparticles (AgNPs). Borohydride‐reduced AgNPs, citrate‐capped AgNPs and polyvinyl pyrrolidone‐capped AgNPs are synthesised and characterised for their size, composition, structure etc. and studied for the suitability in this application. The first two NPs are determined to be suitable for this detection and exhibit a colour change from pale yellow to red at different concentration of melamine. To measure the melamine concentration, quantification of colour change and the transmitted light intensity is done using a colour sensor when the mixture is exposed to standard light source. Compared with visual observation in colour change, the transmitted light intensity provides more information to quantify melamine, more specifically citrate‐capped AgNPs are found to provide better results than borohydride‐reduced AgNPs. The results of this study are much agreeable to that obtained through standard laboratory experiment. Hence, this proposed method would be useful in developing an electronic‐based melamine testing instrument that can be used rapidly at home.
Impact of permittivity and concentration of filler nanoparticles on dielectricpropertiesof polymer nanocomposites
Authors: Kavitha D. , Sindhu T.K. , Nambiar T.N.P.
Published: October 2016

Electrical properties of polymeric insulators can be improved by adding high‐permittivity nanofillers. In this work, the aim is to analyse the effect of filler permittivity, its size, shape, concentration and the interparticle distance on the electrical properties of the nanocomposites. Nanocomposites are fabricated with four types of fillers and with various concentrations and the effect of various filler parameters on permittivity, breakdown strength and loss tangent of the nanocomposites are analysed. Simulation of electric field is used to demonstrate the increase in the volume of enhanced electric field region which affects the short‐time breakdown strength. The effect of filler parameters on the electrical properties of the composite is demonstrated through experimental and theoretical analysis.
Modelling of breather for transformer health assessment
Authors: Kumar Shailesh , Islam Tarikul , Raina Kuldeep Kumar
Published: October 2016

A mathematical model for estimating the moisture content in silica‐gel inside a breather of a power transformer has been developed. The model equations are derived considering the possible real‐time operating conditions of the transformer. These operating conditions are the fast rise or decrease of oil temperature due to a step change in the electrical loads and the cyclic heating and cooling of the oil due to the natural loading of the transformer. An experimental setup has been developed for monitoring the variations in moisture concentration in silica‐gel inside an artificially constructed breather. Finally, the validation of the model has been done with the experimentally obtained data and the standard input signals. The model has been analysed using the equilibrium relations of the moisture concentration between the silica‐gel and the environment of the breather. The response of the model indicates the dynamic behaviour of a moisture sensor placed in the breather. The model has been used in predicting the moisture level in the silica‐gel, the moisture concentration inside the breather and the degradation in the performance of the silica‐gel.
The nearby interstellar medium toward α Leo
Authors: Gry Cecile , Jenkins Edward B.
Published: October 2016

Aims. Our aim is to characterize the conditions in the nearest interstellar cloud.

Methods. We analyze interstellar absorption features in the full UV spectrum of the nearby (d = 24 pc) B8 IVn star α Leo (Regulus). Observations were obtained with STIS at high resolution and high signal-to-noise ratio by the HST ASTRAL Treasury program. We derive column densities for many key atomic species and interpret their partial ionizations.

Results. The gas in front of α Leo exhibits two absorption components. The main one is kinematically identified as the local interstellar cloud (LIC) that surrounds the Sun. The second component is shifted by +5.6 km s-1 relative to the main component, in agreement with results for other lines of sight in this region of the sky, and shares its ionization and physical conditions. The excitation of the C II fine-structure levels and the ratio of Mg I to Mg II reveal a temperature T = 6500 (+750, −600) K and electron density n(e) = 0.11 (+0.025, −0.03) cm-3. Our investigation of the ionization balance yields the ion fractions for 10 different atoms and indicates that about 1/3 of the hydrogen atoms are ionized. Metals are significantly depleted onto grains, with sulfur showing [S/H] ~ −0.27. N(H I) = 1.9 (+0.9, −0.6) × 1018 cm-3, which indicates that this partly neutral gas occupies only 2 to 8 parsecs (about 13%) of the space toward the star, with the remaining volume being filled with a hot gas that emits soft X-rays. We do not detect any absorption features from the highly ionized species that could be produced in an interface between the warm medium and the surrounding hot gas, possibly because of non-equilibrium conditions or a particular magnetic field orientation that reduces thermal conduction. Finally, the radial velocity of the LIC agrees with that of the Local Leo Cold Cloud, indicating that they may be physically related.
Diffusion of helical particles in the screw-like nematic phase
Authors: Cinacchi Giorgio , Pintus Alberto Maria , Tani Alessandro
Published: October 2016

The mechanism of diffusion of helical particles in the new screw-like nematic phase is studied by molecular dynamics numerical simulation. Several dynamical indicators are reported that evidence and microscopically characterise the special translo-rotational motion by which helical particles move in this chiral liquid-crystalline phase. Besides mean square displacements and diffusion coefficients resolved parallel and perpendicular to the nematic director, a suitable translo-rotational van Hove self-correlation function and a sequence of translational and rotational velocity, self- and distinct-, time correlation functions are calculated. The analysis of all these correlation functions elicits the operativeness of the aforementioned coupled mechanism and allows its short- and long-time quantitative characterisation.
Ionic profiles close to dielectric discontinuities: Specific ion-surface interactions
Authors: Markovich Tomer , Andelman David , Orland Henri
Published: October 2016

We study, by incorporating short-range ion-surface interactions, ionic profiles of electrolyte solutions close to a non-charged interface between two dielectric media. In order to account for important correlation effects close to the interface, the ionic profiles are calculated beyond mean-field theory, using the loop expansion of the free energy. We show that how it is possible to overcome the well-known deficiency of the regular loop expansion close to the dielectric jump and treat the non-linear boundary conditions within the framework of field theory. The ionic profiles are obtained analytically to one-loop order in the free energy, and their dependence on different ion-surface interactions is investigated. The Gibbs adsorption isotherm as well as the ionic profiles is used to calculate the surface tension, in agreement with the reverse Hofmeister series. Consequently, from the experimentally measured surface tension, one can extract a single adhesivity parameter, which can be used within our model to quantitatively predict hard to measure ionic profiles.
Response of electron crystals to external excitation with incomplete holding field compensation
Authors: Syvokon V. E. , Nasyedkin K. A. , Sharapova I. V.
Published: October 2016

This is a continuation of an experimental study of the previously observed abrupt change in the conductivity of electron crystals with incomplete compensation of the holding field. Molecular dynamics modelling of the process is used to explain the observed behavior. It is shown that the most likely reason for the response of electron crystals under conditions of incomplete compensation of the holding voltage is features of the capacitance measurements of the transport characteristics of the two-dimensional electron system, rather than changes in the conductivity of the electron layer, as assumed previously.
Role of twins in variations in the conductivity characteristics of single-crystal HoBa2Cu3O7-δ during reversible changes in hydrostatic pressure
Authors: Khadzhai G. Ya. , Nazyrov Z. F. , Vovk R. V.
Published: October 2016

The in-plane electrical resistivity of single-crystal HoBa2Cu3O7-δ (Tc = 62–66 K) is studied at temperatures Tc–300 K under conditions such that the measurement current flows parallel to twins or at an angle of 45° to them during reversible changes in hydrostatic pressure. The variations in Tc, in the parameters of the Bloch-Grueneisen equations, and in the parameters of the Aslamasov-Larkin model for fluctuation conductivity are analyzed. Application of a pressure facilitates the formation of a second phase with lower Tc that shows up more clearly when the measurement current flows across the twinning plane. In this case, the transverse coherence length and the interval within which the fluctuation conductivity exists are smaller than in the first configuration. The relaxation of the parameters characterizing the scatting of charge carriers on phonons and defects is related to the redistribution of oxygen between the two phases.
Superfluidity of a dilute gas of electron-hole pairs in a bilayer system
Authors: Fil D. V. , Shevchenko S. I.
Published: October 2016

The stability conditions for a superfluid phase in double layer systems with pairing of spatially separated electrons and holes were studied in the low density limit, and the general expression for the collective excitation spectrum was obtained. It was shown that as the distance d between the layers increases, a minimum appears in the excitation spectrum. When d reaches a critical value, the superfluid state becomes unstable with respect to the formation of a phase of the Wigner-crystal type. The same instability occurs at a fixed d upon an increase in the density of charge carriers. It was established that the critical distance and the critical density are related through inverse-power dependence. The impact of impurities on the temperature of the superfluid transition was investigated and the conditions under which it is small were established. It was shown that the critical temperature Tc ≈ 100 K can be reached in the diluted systems.
Effect of nuclear structure on the electronic spectrum of the helium atom
Authors: Antsygina T. N. , Chishko K. A.
Published: October 2016

An exact diagonalization method is used to calculate corrections to the ground state of the 4He atom related to the finite size and finite mass of its nucleus, which is interpreted as a bound state of two deuterons in the shell model. The experimentally determined quadrupole moment of the deuteron (Q0 = 2.74 × 10−27 cm2) makes it possible to estimate the size of an individual deuteron and, thereby, the size of the 4He nucleus (d ∼ 1.5 × 10−13 cm). As a result, the 4He nucleus is made up of four nucleons in the ground state (1s)4 in a spherically symmetric shell of diameter d, along which the complete charge (+2e) of the nucleus is uniformly distributed. This distribution, in turn, can be interpreted as the ground state of a rigid rotator with charges of magnitude +e attached to its ends. In this model the nucleus is a charged spherical shell of radius d/2, within which the potential is constant and finite, equal to 4e/d, and outside of which the potential falls off in accordance with the conventional Coulomb law as 2e/r. The existence of a “core” of this kind signifies a correction to the standard Coulomb potential for r < d/2 that reduces the energy of the ground state of the 4He atom by a small amount ε1 but does not lead to any new low-energy levels. This reduction, in turn, is comparable to the correction to the ground state of 4He owing to the finite mass of the nucleus.
Low-temperature magnetic viscosity in thin GaMnSb films containing MnSb clusters
Authors: Dmitriev A. I. , Kostyuchenko S. A.
Published: October 2016

The time dependences of the magnetic moment m(t) of thin GaMnSb films containing MnSb clusters are measured. It is found that the m(t) curves are straight in semilogarithmic coordinates m(lnt). The slope of the m(lnt) lines correspond to the magnetic viscosity S. It is found that the field dependences of the magnetic viscosity S(H) and magnetic moment m(H) at low temperatures are determined by a log-normal distribution of the magnetic anisotropy energy of the MnSb clusters.
Spontaneous polarization of non-stoichiometric LiIO3 crystals in the low-temperature region
Authors: Matyjasik S. , Shaldin Yu. V.
Published: October 2016

Measurements of the total charge Q(T) = SΔPs(T) in non-stoichiometric z-cut LiIO3 samples in the temperature range of 4.2–300 K were reported. The measurements were supplemented with the data on thermally stimulated depolarization induced by an external electric field of different magnitude and polarity. For T > 130 K, anomalies in the ΔPs(T,U) dependence were observed, which are commonly caused by the deviation of the crystal composition from stoichiometry. The possible nature of the non-stoichiometry was clarified with magnetic measurements, which allowed us to detect interstitial Li below 100 K, as well as two paramagnetic associates of unknown nature at 25 K and 50 K. Increasing temperature led to ionization of lithium with formation of Li+ ions and associates, (VO+2e)− and (VO++VLi−)+, responsible for ionic conductivity. It cannot be excluded that during the charge measurements at T > 140 K the associates of a different type (VLi-,Li+) are formed, which possess a dipole moment and can be oriented opposite to ΔPs. It was shown that in a limited temperature range from 18 K to 35 K, the temperature dependence of ΔPs ∼ T4 agrees with the Born theory. Considerable fluctuations of the pyroelectric coefficient were observed, which were presumably related with the disorder of the crystal structure of the non-stoichiometric sample leading to the distribution of relaxation times of the elements of the defect subsystem.
The laws of deformation of an amorphous polyimide (PI) film when it is stretched in the temperature range 1.6–300 K
Authors: Soldatov V. P. , Kirichenko G. I. , Abraimov V. V. , Braude I. S. , Geidarov V. G.
Published: October 2016

A first-time presentation of a wide range of charts imaging the stretch of amorphous polyimide (PI) film samples in the 300–1.6 K temperature range and an analysis of how temperature affects the conditional limit of fluidity, strength, and deformation of this film at the indicated temperatures. The athermal character of the breaking stress below the temperature of liquid nitrogen and its thermally activated behavior above 80 K are demonstrated. We also analyze the features of the behavior of glassy PI film samples that are stretched at low temperatures and then unloaded and warmed up to room temperatures.
Phonon thermal properties of graphene from molecular dynamics using different potentials
Authors: Zou Ji-Hang , Ye Zhen-Qiang , Cao Bing-Yang
Published: October 2016

Phonon thermal transport in graphene has attracted significant interest in recent years. Phonon thermal properties of graphene are investigated by molecular dynamics simulations using the Tersoff, Tersoff-2010, REBO, and AIREBO potentials. By calculating the phonon properties and thermal conductivity of graphene, the performance of the potentials is evaluated based on comparisons with experimental data. It shows that the Tersoff-2010 and REBO display better dispersion curves for graphene than the original Tersoff and AIREBO. The Tersoff-2010 correctly provides the Γ point phonon velocities of the LA and TA branches as well as the G peak frequency with a value of 46 THz. In addition, the acoustic phonon relaxation time derived from the Tersoff-2010 satisfies the ideal relation “τ−1 ∝ ν2.” It is also found that the Tersoff-2010 provides the highest graphene thermal conductivity among the used potentials, and estimates about 30.0% contribution for flexural phonons to the total thermal conductivity. By comparison, the Tersoff-2010 potential is demonstrated to be the most suitable one to describe the phonon thermal properties of graphene.
Study of a high power sine waveguide traveling wave tube amplifier centered at 8 GHz
Authors: Hoff Brad W. , Simon David S. , French David M. , Lau Y. Y. , Wong Patrick
Published: October 2016

Performance of a 20-stage X-band sine waveguide amplifier, driven by a 40 A, 100 kV, cylindrical electron beam, is studied using numerical simulation and interpreted using Pierce's classical traveling wave tube theory. For an input signal power level of 1.8 kW, particle-in-cell simulations predict gain and bandwidth values exceeding 14 dB and 13%, respectively. For an input signal power level of 7.2 kW, particle-in-cell simulations predict gain and bandwidth values exceeding 12 dB and 15%, respectively, with output power levels exceeding 110 kW at peak gain. Also given are: an assessment of the space charge factor (Pierce's QC parameter) for the complex circuit using simulation data, and an evaluation of the harmonic contents in the beam current.
Controlling the optical properties of sputtered-deposited LixV2O5 films
Authors: Muñoz-Castro M. , Berkemeier F. , Schmitz G. , Buchheit A. , Wiemhöfer H.-D.
Published: October 2016

This study examines the influence of lithium intercalation on the optical properties of vanadium pentoxide films. The films with a thickness between 400 and 1000 nm were prepared by DC magnetron sputter deposition. Cyclic voltammetry and chronopotentiometry were used to set a well defined lithiation state of the LixV2O5 films between x = 0 and x = 1. The optical properties of these films were measured by optical reflectometry in the wavelength range between 500 and 1700 nm. From the reflectance data, the refractive index and the extinction coefficient of the films were finally calculated as a function of the wavelength using Cauchy's dispersion model. The results confirm that the optical behavior of LixV2O5 films varies significantly upon lithium insertion. It is demonstrated that the changes produced in the optical properties are completely reversible within the limits of permanent structure changes.
Removing the barrier to the calculation of activation energies
Authors: Mesele Oluwaseun O. , Thompson Ward H.
Published: October 2016

Approaches for directly calculating the activation energy for a chemical reaction from a simulation at a single temperature are explored with applications to both classical and quantum systems. The activation energy is obtained from a time correlation function that can be evaluated from the same molecular dynamics trajectories or quantum dynamics used to evaluate the rate constant itself and thus requires essentially no extra computational work.
Initial stage densification during spark plasma sintering of Fe-based amorphous alloy powder: Analysis of viscous flow
Authors: Paul Tanaji , Harimkar Sandip P.
Published: October 2016

Understanding the mechanism of densification of amorphous alloy powders is important for determining the parameters during sintering of these materials. In this paper, we report on the analysis of densification of Fe48Cr15Mo14Y2C15B6 amorphous alloy powder during spark plasma sintering. Sintering up to 1000 °C resulted in two clearly distinguishable stages of densification: stage I from 320 °C to 740 °C and stage II from 830 °C to 1000 °C. The maximum densification rate during stage I was attained at 585 °C up to which the sample remained fully amorphous. During the entire stage II, the sample was fully crystalline, and the maximum densification rate attained at 935 °C was much lower than that observed during stage I. Viscous flow during stage I was analyzed, yielding an estimate of the activation energy to be 94.0 ± 0.2 kJ mol−1 in the temperature range from 525 °C to 580 °C.
Crystallization of sputter-deposited amorphous Ge films by electron irradiation: Effect of low-flux pre-irradiation
Authors: Okugawa M. , Nakamura R. , Ishimaru M. , Yasuda H. , Numakura H.
Published: October 2016

We investigated the effect of low-flux electron irradiation with 125 keV to sputter-deposited amorphous germanium on the amorphous structure and electron-induced crystallization microstructure by TEM following our previous study on the effect of aging at room temperature. In samples aged for 3 days, coarse, spherical particles about 100 nm in diameter appear dominantly. By low-flux pre-irradiation to the samples, a reduction in the size and number of coarse particles, embedded in the matrix with fine nanograins of the diamond cubic structure, was noted with the increase in fluence. The crystal structure of these coarse particles was found to be not cubic but hexagonal. In samples aged for 4 months, a similar tendency was observed. In samples aged for 7 months, on the other hand, the homogeneous diamond cubic structured nanograins were unchanged by pre-irradiation. These results indicate that pre-irradiation as well as aging modifies the amorphous structure, preventing the appearance of a hexagonal phase. The elimination of a certain amount of medium-range ordered clusters by pre-irradiation, included in as-deposited samples and the samples aged for 4 months, apparently gives rise to a reduction in the size and number of coarse particles with a metastable hexagonal structure.
Temperature stable and fatigue resistant lead-free ceramics for actuators
Authors: Khesro Amir , Wang Dawei , Hussain Fayaz , Sinclair Derek C. , Feteira Antonio , Reaney Ian M.
Published: October 2016

Lead-free ceramics with the composition 0.91K1/2Bi1/2TiO3–0.09(0.82BiFeO3-0.15NdFeO3-0.03Nd2/3TiO3) were prepared using a conventional solid state, mixed oxide route. The ceramics exhibited a high strain of 0.16% at 6 kV mm−1, stable from room temperature to 175 °C, with a variation of <10%. The materials were fabricated into multilayer structures by co-firing with Pt internal electrodes. The prototype multilayer actuator exhibited constant strains up to 300 °C with a variation of ∼15%. The composition showed fatigue resistant behaviour in both monolithic and multilayer form after bipolar loading of 106 cycles.