bluuebunny/crossref_metadata_2025 huggingface dataset:
Polyhydroxycurcuminoids but not curcumin upregulate neprilysin and can be applied to the prevention of Alzheimer’s disease
Authors: Chen Po-Ting , Chen Zih-ten , Hou Wen-Chi , Yu Lung-Chih , Chen Rita P.-Y.
Published: July 2016

Neprilysin (NEP) is the most important Aβ-degrading enzyme. Its expression level decreases with age and inversely correlated with amyloid accumulation, suggesting its correlation with the late-onset of Alzheimer’s disease. Recently, many reports showed that upregulating NEP level is a promising strategy in the prevention and therapy of Alzheimer’s disease. Here, we used a sensitive fluorescence-based Aβ digestion assay to screen 25 curcumin analogs for their ability to upregulate NEP activity. To our surprise, four compounds, dihydroxylated curcumin, monohydroxylated demethoxycurcumin and mono- and di-hydroxylated bisdemethoxycurcumin, increased NEP activity, while curcumin did not. The ability of these polyhydroxycurcuminoids to upregulate NEP was further confirmed by mRNA and protein expression levels in the cell and mouse models. Finally, feeding monohydroxylated demethoxycurcumin (also named demethylcurcumin) or dihydroxylated bisdemethoxycurcumin (also named bisdemethylcurcumin) to APPswe/PS1dE9 double transgenic mice upregulated NEP levels in the brain and reduced Aβ accumulation in the hippocampus and cortex. These polyhydroxycurcuminoids offer hope in the prevention of Alzheimer’s disease.
Polymer physics of chromosome large-scale 3D organisation
Authors: Chiariello Andrea M. , Annunziatella Carlo , Bianco Simona , Esposito Andrea , Nicodemi Mario
Published: July 2016

Chromosomes have a complex architecture in the cell nucleus, which serves vital functional purposes, yet its structure and folding mechanisms remain still incompletely understood. Here we show that genome-wide chromatin architecture data, as mapped by Hi-C methods across mammalian cell types and chromosomes, are well described by classical scaling concepts of polymer physics, from the sub-Mb to chromosomal scales. Chromatin is a complex mixture of different regions, folded in the conformational classes predicted by polymer thermodynamics. The contact matrix of the Sox9 locus, a region linked to severe human congenital diseases, is derived with high accuracy in mESCs and its molecular determinants identified by the theory; Sox9 self-assembles hierarchically in higher-order domains, involving abundant many-body contacts. Our approach is also applied to the Bmp7 locus. Finally, the model predictions on the effects of mutations on folding are tested against available data on a deletion in the Xist locus. Our results can help progressing new diagnostic tools for diseases linked to chromatin misfolding.
Function of human pluripotent stem cell-derived photoreceptor progenitors in blind mice
Authors: Barnea-Cramer Alona O. , Wang Wei , Lu Shi-Jiang , Singh Mandeep S. , Luo Chenmei , Huo Hongguang , McClements Michelle E. , Barnard Alun R. , MacLaren Robert E. , Lanza Robert
Published: July 2016

Photoreceptor degeneration due to retinitis pigmentosa (RP) is a primary cause of inherited retinal blindness. Photoreceptor cell-replacement may hold the potential for repair in a completely degenerate retina by reinstating light sensitive cells to form connections that relay information to downstream retinal layers. This study assessed the therapeutic potential of photoreceptor progenitors derived from human embryonic and induced pluripotent stem cells (ESCs and iPSCs) using a protocol that is suitable for future clinical trials. ESCs and iPSCs were cultured in four specific stages under defined conditions, resulting in generation of a near-homogeneous population of photoreceptor-like progenitors. Following transplantation into mice with end-stage retinal degeneration, these cells differentiated into photoreceptors and formed a cell layer connected with host retinal neurons. Visual function was partially restored in treated animals, as evidenced by two visual behavioral tests. Furthermore, the magnitude of functional improvement was positively correlated with the number of engrafted cells. Similar efficacy was observed using either ESCs or iPSCs as source material. These data validate the potential of human pluripotent stem cells for photoreceptor replacement therapies aimed at photoreceptor regeneration in retinal disease.
Facile synthesis of hybrid CNTs/NiCo2S4 composite for high performance supercapacitors
Authors: Li Delong , Gong Youning , Pan Chunxu
Published: July 2016

In this work, a novel carbon nanotubes (CNTs)/NiCo2S4 composite for high performance supercapacitors was prepared via a simple chemical bath deposition combined with a post-anion exchange reaction. The morphologies and phase structures of the composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and low-temperature sorption of nitrogen (BET). The electro-chemical tests revealed that the CNT/NiCo2S4 composite exhibited high electrochemical performance, because the CNTs were used as a conductive network for the NiCo2S4 hexagonal nanoplates. Compared with pure NiCo2S4 and the mechanically mixed CNTs/NiCo2S4 composite, the CNTs/NiCo2S4 composite electrode material exhibited excellent supercapacitive performance, such as a high specific capacitance up to 1537 F/g (discharge current density of 1 A/g) and an outstanding rate capability of 78.1% retention as the discharge current density increased to 100 A/g. It is therefore expected to be a promising alternative material in the area of energy storage.
Unravelling the community structure of the climate system by using lags and symbolic time-series analysis
Authors: Tirabassi Giulio , Masoller Cristina
Published: July 2016

Many natural systems can be represented by complex networks of dynamical units with modular structure in the form of communities of densely interconnected nodes. Unraveling this community structure from observed data requires the development of appropriate tools, particularly when the nodes are embedded in a regular space grid and the datasets are short and noisy. Here we propose two methods to identify communities and validate them with the analysis of climate datasets recorded at a regular grid of geographical locations covering the Earth surface. By identifying mutual lags among time-series recorded at different grid points and by applying symbolic time-series analysis, we are able to extract meaningful regional communities, which can be interpreted in terms of large-scale climate phenomena. The methods proposed here are valuable tools for the study of other systems represented by networks of dynamical units, allowing the identification of communities, through time-series analysis of the observed output signals.
Eco-friendly nitrogen-containing carbon encapsulated LiMn2O4 cathodes to enhance the electrochemical properties in rechargeable Li-ion batteries
Authors: Ilango P. Robert , Prasanna K. , Do Su Jung , Jo Yong Nam , Lee Chang Woo
Published: July 2016

This study describes the synthesis of nitrogen-containing carbon (N-C) and an approach to apply the N-C material as a surface encapsulant of LiMn2O4 (LMO) cathode material. The N heteroatoms in the N-C material improve the electrochemical performance of LMO. A low-cost wet coating method was used to prepare N-C@LMO particles. The N-C@LMO was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), high-resolution Raman spectroscopy (HR-Raman), field emission scanning electron microscopy (FE-SEM) and field emission scanning transmission electron microscopy (FE-TEM) with elemental mapping. Furthermore, the prepared samples were electrochemically studied using the AC electrochemical impedance spectroscopy (EIS) and the electrochemical cycler. XPS suggested that the N-C coating greatly reduced the dissolution of Mn and EIS showed that the coating greatly suppressed the charge transfer resistance, even after long-term cycling. The control of Mn dissolution and inner resistance allowed faster Li-ion transport between the two electrodes resulting in improved discharge capacity and cycling stability.
The roles of amensalistic and commensalistic interactions in large ecological network stability
Authors: Mougi Akihiko
Published: July 2016

Ecological communities comprise diverse species and their interactions. Notably, ecological and evolutionary studies have revealed that reciprocal interactions such as predator–prey, competition and mutualism, are key drivers of community dynamics. However, there is an argument that many species interactions are asymmetric, where one species unilaterally affects another species (amensalism or commensalism). This raises the unanswered question of what is the role of unilateral interactions in community dynamics. Here I use a theoretical approach to demonstrate that unilateral interactions greatly enhance community stability. The results suggested that amensalism and commensalism were more stabilizing than symmetrical interactions, such as competition and mutualism, but they were less stabilizing than an asymmetric antagonistic interaction. A mix of unilateral interactions increased stability. Furthermore, in communities with all interaction types, unilateral interactions tended to increase stability. This study suggests that unilateral interactions play a major role in maintaining communities, underlining the need to further investigate their roles in ecosystem dynamics.
A cross-shear deformation for optimizing the strength and ductility of AZ31 magnesium alloys
Authors: Hamad Kotiba , Ko Young Gun
Published: July 2016

Magnesium alloys have recently attracted great interest due their lightweight and high specific strength. However, because of their hexagonal close-packed structure, they have few active slip systems, resulting in poor ductility and high mechanical anisotropy at room temperature. In the present work, we used a cross-shear deformation imposed by a differential speed rolling (DSR) technique to improve the room temperature strength and ductility of AZ31 magnesium alloy sheets. To introduce the cross-shear deformation, the sheets were rotated 180° around their longitudinal axis between the adjacent passes of DSR. The sheets of the AZ31 alloy subjected to the cross-shear deformation showed a uniform fine microstructure (1.2 ± 0.1 μm) with weak basal textures. The fabricated sheets showed a simultaneous high ultimate tensile strength and elongation-to-failure, i.e., ~333 MPa and ~21%, respectively. These were explained based on the structural features evolved due to the cross-shear deformation by DSR. The high strength was attributed to the uniform fine microstructure, whereas the high ductility was explained based on the basal texture weakening.
A magnetic core–shell Fe3O4@SiO2/MWCNT nanocomposite modified carbon paste electrode for amplified electrochemical sensing of amlodipine and hydrochlorothiazide
Authors: Beitollahi Hadi , Ebadinejad Farshid , Shojaie Fahimeh , Torkzadeh-Mahani Masoud
Published: July 2016

A novel carbon paste electrode for the simultaneous determination of amlodipine and hydrochlorothiazide is constructed.
Determination of mefenamic acid in urine and pharmaceutical samples by HPLC after pipette-tip solid phase microextraction using zinc sulfide modified carbon nanotubes
Authors: Rezaei Kahkha Mohammad Reza , Kaykhaii Massoud , Afarani Mahdi Shafiee , Sepehri Zahra
Published: July 2016

In this work, a novel solid phase microextraction based on a carbon nanotube–zinc sulfide nano-composite was developed and applied for the extraction and HPLC determination of trace amounts of mefenamic acid in urine samples.
Chiral supramolecular polymerization leading to eye differentiable circular polarization in luminescence
Authors: Kumar Jatish , Marydasan Betsy , Nakashima Takuya , Kawai Tsuyoshi , Yuasa Junpei
Published: July 2016

A simple methodology to tune the chiroptical properties of a europium(iii) complex in helical supramolecular polymerization is demonstrated wherein aggregation leads to enhanced luminescence dissymmetry.
Exploration of a calcium–organic framework as an anode material for sodium-ion batteries
Authors: Zhang Yan , Niu Yubin , Wang Min-Qiang , Yang Jingang , Lu Shiyu , Han Jin , Bao Shu-Juan , Xu Maowen
Published: July 2016

In this communication, we designed and synthesized a novel calcium–organic framework and presented it as an anode material for sodium-ion batteries.
The influence of metal-ion binding on the structure and surface composition of Sonic Hedgehog: a combined classical and hybrid QM/MM MD study
Authors: Hitzenberger Manuel , Hofer Thomas S.
Published: July 2016

The interaction of metal ions with Shh binding-sites and their structural impact are assessed via classical and quantum mechanical simulations.
Excellent performance in hydrogenation of esters over Cu/ZrO2 catalyst prepared by bio-derived salicylic acid
Authors: Ding Jian , Liu Yanting , Zhang Juan , Liu Kefeng , Xiao Haicheng , Kong Fanhua , Sun Yanping , Chen Jiangang
Published: July 2016

A variety of bio-derived organic carboxylic acids are used to prepare Cu/ZrO2. In particular, salicylic acid provides superb control over the distribution of small Cu particles on t-ZrO2, which affords enhanced catalytic activity.
Oxygen reduction reaction at LaxCa1−xMnO3 nanostructures: interplay between A-site segregation and B-site valency
Authors: Celorrio Verónica , Calvillo Laura , Dann Ellie , Granozzi Gaetano , Aguadero Ainara , Kramer Denis , Russell Andrea E. , Fermín David J.
Published: July 2016

Detailed surface vs. bulk composition studies of LaxCa1−xMnO3 oxides provide clear evidence that the ORR activity increases as the effective electron population at the Mn site increases.
Density functional calculations reveal a flexible version of the copper paddlewheel unit: implications for metal organic frameworks
Authors: Alzahrani K. A. H. , Deeth R. J.
Published: July 2016

Coordination of N-heterocyclic carbenes to the apical sites of copper paddlewheel dimers switches the direction of the Jahn–Teller axis and confers enhanced dynamic flexibility.
Anchoring of Ag6Si2O7 nanoparticles on α-Fe2O3 short nanotubes as a Z-scheme photocatalyst for improving their photocatalytic performances
Authors: Liu Jun , Wu Wei , Tian Qingyong , Dai Zhigao , Wu Zhaohui , Xiao Xiangheng , Jiang Changzhong
Published: July 2016

α-Fe2O3/Ag6Si2O7 p–n heterostructures with well-defined morphology were synthesized and their photocurrent intensity is improved 62 times compared with pure α-Fe2O3 SNTs.
Cyclodextrins as effective additives in AuNP-catalyzed reduction of nitrobenzene derivatives in a ball-mill
Authors: Menuel S. , Léger B. , Addad A. , Monflier E. , Hapiot F.
Published: July 2016

At the boundary between mechanochemistry, supramolecular chemistry and catalysis, the present study explores the role of cyclodextrins (CDs) and other saccharide additives in the mechanosynthesis of gold nanoparticles (AuNPs) and their use as catalysts in the reduction of substituted nitrobenzene derivatives.
Tin-free visible light photoredox catalysed cyclisation of enamides as a mild procedure for the synthesis of γ-lactams
Authors: Fava Eleonora , Nakajima Masaki , Tabak Martin B. , Rueping Magnus
Published: July 2016

A visible light mediated tin-free 5-endo-trigcyclisation of α-chloroenamides, leading to synthetically valuable γ-lactams in good yields and high diastereomeric ratios, was developed.
Dimension conversion and scaling of disordered protein chains
Authors: Li Maodong , Sun Tanlin , Jin Fan , Yu Daqi , Liu Zhirong
Published: July 2016

To extract protein dimension and energetics information from single-molecule fluorescence resonance energy transfer spectroscopy (smFRET) data, it is essential to establish the relationship between the distributions of the radius of gyration (Rg) and the end-to-end (donor-to-acceptor) distance (Ree).
Design and synthesis of selective, small molecule inhibitors of coactivator-associated arginine methyltransferase 1 (CARM1)
Authors: Kaniskan H. Ü. , Eram M. S. , Liu J. , Smil D. , Martini M. L. , Shen Y. , Santhakumar V. , Brown P. J. , Arrowsmith C. H. , Vedadi M. , Jin J.
Published: July 2016

Structure–activity relationship studies, starting from a fragment hit, resulted in discovery of the compound 9, an inhibitor of CARM1 with high potency and selectivity.
Copper-catalysed oxidative amination of quinoxalin-2(1H)-ones with aliphatic amines
Authors: Li Yi , Gao Ming , Wang Lianhui , Cui Xiuling
Published: July 2016

A novel, efficient and practical method for copper-catalysed oxidative C-3 amination of quinoxalin-2(1H)-ones with primary or secondary amines as the nitrogen sources has been developed.
General synthesis of P-stereogenic compounds: the menthyl phosphinate approach
Authors: Berger Olivier , Montchamp Jean-Luc
Published: July 2016

Easily prepared menthyl phosphinates of high diastereoisomeric purity provide versatile intermediates for the synthesis ofP-stereogenic compounds.
The effect of fluorination on the photovoltaic performance of the D–A copolymers containing naphtho[2,3-c]thiophene-4,9-dione and bithiophene moieties
Authors: He Dan , Geng Xinjian , Ding Liming
Published: July 2016

Fluorine improves the planarity of the polymer backbone via its lock-up function. Polymer PFNTDFBT shows a high mobility and its solar cells gave a PCE of 7.79%.
Paper-based SERS active substrates on demand
Authors: Joshi Pushkaraj , Santhanam Venugopal
Published: July 2016

Latent silver clusters within silver halide films can be developed into SERS active substrates on demand.
Simple combination of humic acid with biogenic hydroxyapatite achieved highly efficient removal of methylene blue from aqueous solution
Authors: Wang Gang , Yang Lei , Jiang Ling , Shi Mengqi , Wei Zhenggui , Zhong Wenhui , Li Shiyin , Cui Jing , Wei Wei
Published: July 2016

Simple combination of HA with bHAP significantly enhances MB removal from aqueous solution with a qmax of 393.47 mg g−1.
Effects of hydroxyapatite (0001) Ca2+/Mg2+substitution on adsorbedd-ribose ring puckering
Authors: Revilla-López Guillem , Bertran Oscar , Casanovas Jordi , Turon Pau , Puiggalí Jordi , Alemán Carlos
Published: July 2016

Advanced Molecular Dynamics (MD) simulation protocols have been used to assess the ring puckering of cyclicd-ribose when the sugar is adsorbed on the most stable (0001) facet of calcium hydroxyapatite (HAp).
Cu2O sensitized flexible 3D-TiO2 nanotube arrays for enhancing visible photo-electrochemical performance
Authors: Yang Xiuchun , Chen Chao
Published: July 2016

Cu2O flake and nanoparticle modified 3D-TiO2 nanotube arrays were firstly prepared by electrochemical deposition. The growth process of Cu2O is discussed. A mechanism is proposed to explain the difference in photocurrent response and photo-catalytic activity.
Comparison of three deep eutectic solvents and 1-ethyl-3-methylimidazolium acetate in the pretreatment of lignocellulose: effect on enzyme stability, lignocellulose digestibility and one-pot hydrolysis
Authors: Wahlström Ronny , Hiltunen Jaakko , Pitaluga de Souza Nascente Sirkka Mariáh , Vuoti Sauli , Kruus Kristiina
Published: July 2016

The use of [EMIM]AcO and three DESs was compared in lignocellulose pretreatment with focus on cellulase stability, effects on lignocellulose and enzymatic hydrolysis of pretreated lignocellulose in both buffer and in solutions of ionic liquid or DES.
A tumor-targeting drug delivery system based on cyclic NGR-modified, combretastatin A4-loaded, functionalized graphene oxide nanosheets
Authors: Ding Fang , Wu Fanhong , Tian Qingqing , Guo Lingling , Wang Jing , Xiao Fanhua , Yu Yanyan
Published: July 2016

Graphene oxide has shown great potential in drug delivery.
La and F co-doped Bi2MoO6 architectures with enhanced photocatalytic performance via synergistic effect
Authors: Wang Danjun , Shen Huidong , Guo Li , Wang Chan , Fu Feng , Liang Yucang
Published: July 2016

Solvothermally-synthesized La and F co-doped Bi2MoO6 architectures showed significantly enhanced photocatalytic activities and the photocatalytic mechanism was proposed.
Monodisperse Ag–AgBr nanocrystals anchored on one-dimensional TiO2 nanotubes with efficient plasmon-assisted photocatalytic performance
Authors: Xue Chao , Yan Xiaoqing , Ding Shujiang , Yang Guidong
Published: July 2016

A novel ternary Ag–AgBr/TiO2 plasmonic nanotube heterojunction photocatalyst was fabricated, showing a very high-performance for decomposition of organic pollutants.
Heterocyclic aminopyrazine–reduced graphene oxide coated carbon cloth electrode as an active bio-electrocatalyst for extracellular electron transfer in microbial fuel cells
Authors: Gangadharan Praveena , Nambi Indumathi M. , Senthilnathan Jaganathan , V. M. Pavithra
Published: July 2016

In the present study, a low molecular heterocyclic aminopyrazine (Apy)–reduced graphene oxide (r-GO) hybrid coated carbon cloth (r-GO–Apy–CC) was employed as an active and stable bio-electro catalyst in a microbial fuel cell (MFC).
A switchable electrochemical redox ratiometric substrate based on ferrocene for highly selective and sensitive fluoride detection
Authors: Manibalan Kesavan , Mani Veerappan , Huang Sheng-Tung
Published: July 2016

A ferrocene based electrochemical redox substrate for highly selective and sensitive fluoride detection in non-transparent solutions.
Gold nanoparticles (GNP) induced redox modulation in organoselenium compounds: distinction between cyclic vs. linear structures
Authors: Kumar Pavitra V. , Singh Beena G. , Ballal Anand , Jain Vimal K. , Iwaoka Michio , Priyadarsini K. Indira
Published: July 2016

Structure of organoselenium compounds affects their binding with gold nanoparticles and modulates their redox behaviour and radiation induced oxidative degradation.
Mechanical oscillation of dynamic microtubule rings
Authors: Ito Masaki , Rashedul Kabir Arif Md. , Islam Md. Sirajul , Inoue Daisuke , Wada Shoki , Sada Kazuki , Konagaya Akihiko , Kakugo Akira
Published: July 2016

Microtubules driven by kinesins self-assemble into ring-shaped structures which exhibit dynamic reorganization at an air-buffer interface.
Power from nature: designing green battery materials from electroactive quinone derivatives and organic polymers
Authors: Miroshnikov Mikhail , Divya Kizhmuri P. , Babu Ganguli , Meiyazhagan Ashokkumar , Reddy Arava Leela Mohana , Ajayan Pulickel M. , John George
Published: July 2016

A review highlighting the unique chemistry of quinones and associated polymers as nature-derived electrode materials for green battery applications.
Intelligent sponge with reversibly tunable super-wettability: robust for effective oil–water separation as both the absorber and filter tolerate fouling and harsh environments
Authors: Li Lingjie , Liu Lei , Lei Jinglei , He Jianxin , Li Nianbing , Pan Fusheng
Published: July 2016

The as-prepared sponge demonstrates intelligent reversibly tunable super-wettability, excellent antifouling ability, robustness and flexible applications for effective oil–water separation in harsh environments.
A Ni2P nanosheet array integrated on 3D Ni foam: an efficient, robust and reusable monolithic catalyst for the hydrolytic dehydrogenation of ammonia borane toward on-demand hydrogen generation
Authors: Tang Chun , Xie Lisi , Wang Kunyang , Du Gu , Asiri Abdullah M. , Luo Yonglan , Sun Xuping
Published: July 2016

A Ni2P nanosheet array integrated on Ni foam performs as a catalyst for on-demand hydrogen production from ammonia borane with an initial turnover frequency of 42.3 mol(H2) mol(Ni2P)−1 min−1 and an activation energy of 44.0 kJ mol−1.
Vertically aligned multi walled carbon nanotubes prevent biofilm formation of medically relevant bacteria
Authors: Malek I. , Schaber C. F. , Heinlein T. , Schneider J. J. , Gorb S. N. , Schmitz R. A.
Published: July 2016

Biofilm formation of clinically relevant bacterial strains –Klebsiella oxytoca, Pseudomonas aeruginosa and Staphylococcus epidermidis– is inhibited on MWCNT.
Selective sensing of isoprene by Ti-doped ZnO for breath diagnostics
Authors: Güntner A. T. , Pineau N. J. , Chie D. , Krumeich F. , Pratsinis S. E.
Published: July 2016

Exhaled isoprene could enable non-invasive monitoring of cholesterol-lowering therapy. This isoprene-selective Ti-doped ZnO gas sensor can detect isoprene down to 5 ppb at high response (>15 times higher than pure ZnO) and 90% relative humidity.
Tunable optical absorption in silicene molecules
Authors: Mokkath Junais Habeeb , Schwingenschlögl Udo
Published: July 2016

Two-dimensional materials with a tunable band gap that covers a wide range of the solar spectrum hold great promise for sunlight harvesting.
Charge pump‐ and VCO‐based second‐order delta‐sigma ADC
Authors: Xing Xinpeng , Zhu Peng , Liu Hui , Liu Ye , Gielen Georges
Published: July 2016

A low‐power charge pump‐ and VCO‐based delta‐sigma ADC is presented, realising second‐order noise shaping without any analogue integrator. The proposed synchronous pulse‐width modulator ‐driven charge pump replaces an analogue integrator in delta‐sigma ADC power efficiently. Together with the noise shaping provided by the VCO in the quantiser, an analogue‐less 2nd‐order delta‐sigma ADC is obtained. The simulation results in 90 nm CMOS show that the proposed charge pump‐ and VCO‐based delta‐sigma ADC achieves 78.7 dB signal‐to‐noise ratio and 74.2 dB signal‐to‐noise and distortion ratio for a bandwidth of 2 MHz, consuming 2.95 mW, corresponding to a FoM of 0.18 pJ/conv.
Simple VCO nonlinearity correction algorithm based on EMD in FMCW radar system
Authors: Hong J. , Cheon C.
Published: July 2016

A simple software correction algorithm based on the empirical mode decomposition (EMD) algorithm to correct the nonlinearity of a VCO is proposed. The proposed algorithm divides a dechirp signal into mono‐component signals using EMD so that the nonlinearity is extracted from the decomposed components in the form of phase distortion. The phase distortion due to nonlinearity is compensated by using the resampling method. As a result, the proposed algorithm corrects the phase distortion without assistance from any additional hardware, thus maintaining simplicity and cost effectiveness. The proposed algorithm is verified by a simulation and an experiment, and it yields well corrected range profiles.
Design and realisation of radio‐frequency attenuators based on microelectromechanical system switches
Authors: Nan Xueli , Zhang Binzhen , Yang Xin , Ge Shaolei
Published: July 2016

Radio‐frequency (RF) attenuators show unique advantages and a great development potential in phased array radars. A kind of programmable step attenuators with high precision based on contact‐type microelectromechanical system series switches is proposed herein. This work paid attention to the design and fabrication of switches – the key components of attenuators. By setting up vent holes on the pull‐down plates of switches, the mass of plates was reduced, together with the decreased influence of air damping. Meanwhile, switches were manufactured and packaged through ultraviolet lithography (UV‐LIGA) technology with the S parameter test being performed. Results showed that the insertion loss in a range of 0.3 and 1.8 dB under the condition that attenuation modules are short‐circuited at the same time, which is basically the same with the simulation results of 0.1–1.3 dB. While all the return losses S 11 were <15 dB expect from that at 10 dB. In addition, the designed attenuator showed gentle attenuation in a range of DC ∼20 GHz. However, on the whole, the deviation is controlled within 2 dB, which is basically consistent with the design results of 1 dB. It can be found from the obtained results that all indices of the attenuator satisfied the design requirements.
Static and dynamic properties of supercooled water in small nanotubes
Authors: Khademi Mahdi , Sahimi Muhammad
Published: July 2016

The static and dynamic properties of water in small silicon-carbide and carbon nanotubes have been studied over the temperature range 100 K–298 K, using extensive molecular dynamics simulations. The computed properties include the radial distribution function, the cage correlation function, the space-time autocorrelation function, the velocity autocorrelation function, and the self-diffusivity. They all indicate that, under the conditions that we study, water does not freeze in small nanotubes; the Stokes-Einstein relation breaks down, and the self-diffusivity exhibits a transition around 230 K, very close to 228 K, the temperature at which a fragile-to-strong dynamic crossover is supposed to happen. The cage correlation function C(t) decays according to a stretched-exponential function, C(t) ∼ exp[ − (t/τ)β], where τ is a relaxation time and β is a topological exponent.
A visualization instrument to investigate the mechanical-electro properties of high temperature superconducting tapes under multi-fields
Authors: Liu Wei , Zhang Xingyi , Liu Cong , Zhang Wentao , Zhou Jun , Zhou YouHe
Published: July 2016

We construct a visible instrument to study the mechanical-electro behaviors of high temperature superconducting tape as a function of magnetic field, strain, and temperature. This apparatus is directly cooled by a commercial Gifford-McMahon cryocooler. The minimum temperature of sample can be 8.75 K. A proportion integration differentiation temperature control is used, which is capable of producing continuous variation of specimen temperature from 8.75 K to 300 K with an optional temperature sweep rate. We use an external loading device to stretch the superconducting tape quasi-statically with the maximum tension strain of 20%. A superconducting magnet manufactured by the NbTi strand is applied to provide magnetic field up to 5 T with a homogeneous range of 110 mm. The maximum fluctuation of the magnetic field is less than 1%. We design a kind of superconducting lead composed of YBa2Cu3O7-x coated conductor and beryllium copper alloy (BeCu) to transfer DC to the superconducting sample with the maximum value of 600 A. Most notably, this apparatus allows in situ observation of the electromagnetic property of superconducting tape using the classical magnetic-optical imaging.
A novel lobster-eye imaging system based on Schmidt-type objective for X-ray-backscattering inspection
Authors: Xu Jie , Wang Xin , Zhan Qi , Huang Shengling , Chen Yifan , Mu Baozhong
Published: July 2016

This paper presents a novel lobster-eye imaging system for X-ray-backscattering inspection. The system was designed by modifying the Schmidt geometry into a treble-lens structure in order to reduce the resolution difference between the vertical and horizontal directions, as indicated by ray-tracing simulations. The lobster-eye X-ray imaging system is capable of operating over a wide range of photon energies up to 100 keV. In addition, the optics of the lobster-eye X-ray imaging system was tested to verify that they meet the requirements. X-ray-backscattering imaging experiments were performed in which T-shaped polymethyl-methacrylate objects were imaged by the lobster-eye X-ray imaging system based on both the double-lens and treble-lens Schmidt objectives. The results show similar resolution of the treble-lens Schmidt objective in both the vertical and horizontal directions. Moreover, imaging experiments were performed using a second treble-lens Schmidt objective with higher resolution. The results show that for a field of view of over 200 mm and with a 500 mm object distance, this lobster-eye X-ray imaging system based on a treble-lens Schmidt objective offers a spatial resolution of approximately 3 mm.
Influence of amorphous structure on polymorphism in vanadia
Authors: Stone Kevin H. , Schelhas Laura T. , Garten Lauren M. , Shyam Badri , Mehta Apurva , Ndione Paul F. , Ginley David S. , Toney Michael F.
Published: July 2016

Normally we think of the glassy state as a single phase and therefore crystallization from chemically identical amorphous precursors should be identical. Here we show that the local structure of an amorphous precursor is distinct depending on the initial deposition conditions, resulting in significant differences in the final state material. Using grazing incidence total x-ray scattering, we have determined the local structure in amorphous thin films of vanadium oxide grown under different conditions using pulsed laser deposition (PLD). Here we show that the subsequent crystallization of films deposited using different initial PLD conditions result in the formation of different polymorphs of VO2. This suggests the possibility of controlling the formation of metastable polymorphs by tuning the initial amorphous structure to different formation pathways.
MegaOhm extraordinary Hall effect in oxidized CoFeB
Authors: Kopnov G. , Gerber A.
Published: July 2016

We report on the development of controllably oxidized CoFeB ferromagnetic films demonstrating the extraordinary Hall effect (EHE) resistivity exceeding 1 Ω cm and magnetic field sensitivity up to 106 Ω/T. Such EHE resistivity is four orders of magnitude higher than that previously observed in ferromagnetic materials, while sensitivity is two orders larger than the best of semiconductors.
Calculation of x-ray scattering patterns from nanocrystals at high x-ray intensity
Authors: Abdullah Malik Muhammad , Jurek Zoltan , Son Sang-Kil , Santra Robin
Published: July 2016

We present a generalized method to describe the x-ray scattering intensity of the Bragg spots in a diffraction pattern from nanocrystals exposed to intense x-ray pulses. Our method involves the subdivision of a crystal into smaller units. In order to calculate the dynamics within every unit, we employ a Monte-Carlo-molecular dynamics-ab-initio hybrid framework using real space periodic boundary conditions. By combining all the units, we simulate the diffraction pattern of a crystal larger than the transverse x-ray beam profile, a situation commonly encountered in femtosecond nanocrystallography experiments with focused x-ray free-electron laser radiation. Radiation damage is not spatially uniform and depends on the fluence associated with each specific region inside the crystal. To investigate the effects of uniform and non-uniform fluence distribution, we have used two different spatial beam profiles, Gaussian and flattop.
Nanochannel flow past permeable walls via molecular dynamics
Authors: Xie Jian-Fei , Cao Bing-Yang
Published: July 2016

The nanochannel flow past permeable walls with nanopores is investigated by molecular dynamics (MD) simulations, including the density distribution, velocity field, molecular penetration mechanism and surface friction coefficient. A low density distribution has been found at the gas-wall interface demonstrating the low pressure region. In addition, there exists a jump of the gas density on the permeable surface, which indicates the discontinuity of the density distribution across the permeable surface. On the other hand, the nanoscale vortices are observed in nanopores of the permeable wall, and the reduced mass flux of the flow in nanopores results in a shifted hydrodynamic boundary above the permeable surface. Particularly the slip length of the gas flow on the permeable surface is pronounced a non-linear function of the molecular mean free path, which produces a large value of the tangential momentum accommodation coefficient (TMAC) and a big portion of the diffusive refection. Moreover, the gas-gas interaction and multi-collision among gas molecules may take place in nanopores, which contribute to large values of TMAC. Consequently the boundary friction coefficient on the permeable surface is increased because of the energy dissipation consumed by the nanoscale vortices in nanopores. The molecular boundary condition provides us with a new picture of the nanochannel flow past the permeable wall with nanopores.
Impact of young ewe fertility rate on risk and genetic gain in sheep-breeding programs using genomic selection
Authors: Newton J. E. , Brown D. J. , Dominik S. , van der Werf J. H. J.
Published: July 2016

Genomic selection could be useful in sheep-breeding programs, especially if rams and ewes are first mated at an earlier age than is the current industry practice. However, young-ewe (1 year old) fertility rates are known to be lower and more variable than those of mature ewes. The aim of the present study was to evaluate how young-ewe fertility rate affects risk and expected genetic gain in Australian sheep-breeding programs that use genomic information and select ewes and rams at different ages. The study used stochastic simulation to model different flock age structures and young-ewe fertility levels with and without genomic information for Merino and maternal sheep-breeding programs. The results from 10 years of selection were used to compare breeding programs on the basis of the mean and variation in genetic gain. Ram and ewe age, availability of genomic information on males and young-ewe fertility level all significantly (P < 0.05) affected expected genetic gain. Higher young-ewe fertility rates significantly increased expected genetic gain. Low fertility rate of young ewes (10%) resulted in net genetic gain similar to not selecting ewes until they were 19 months old and did not increase breeding-program risk, as the likelihood of genetic gain being lower than the range of possible solutions from a breeding program with late selection of both sexes was zero. Genomic information was of significantly (P < 0.05) more value for 1-year-old rams than for 2-year-old rams. Unless genomic information was available, early mating of rams offered no greater gain in Merino breeding programs and increased breeding-program risk. It is concluded that genomic information decreases the risk associated with selecting replacements at 7 months of age. Genetic progress is unlikely to be adversely affected if fertility levels above 10% can be achieved. Whether the joining of young ewes is a viable management decision for a breeder will depend on the fertility level that can be achieved in their young ewes and on other costs associated with the early mating of ewes.
Ginsenoside Re improves skin barrier function in HaCaT keratinocytes under normal growth conditions
Authors: Oh Yuri , Lim Hye-Won , Kim Kyunghoon , Lim Chang-Jin
Published: July 2016

Ginsenoside Re (Re), a major ginsenoside of ginseng, enhanced the cornified cell envelope (CE) formation in HaCaT keratinocytes under normal conditions. In HaCaT keratinocytes, Re was also able to upregulate filaggrin protein and caspase-14 activity in a concentration-dependent manner. These findings reasonably imply that Re possesses a desirable property of improving skin barrier function.
Global justice, international relations and the Sustainable Development Goals' quest for poverty eradication
Authors: Cimadamore Alberto D.
Published: July 2016

The paper examines the notion of global justice in the changing context of International Relations and the Sustainable Development Goals (SDGs) approved by world leaders in 2015. Structural differentiation of states and the international system is presented as a way to explain limitations and possibilities in the quest of poverty eradication and global justice. The paper ends by assessing how international poverty law and human rights approaches can team up in the search for accountability, defined as the key to transit towards a more just world. It concludes that the political and legal responsibilities emerging from the universal policy agenda of the SDGs (to be implemented according to rights and obligations of states under international law) could pave the way towards global (social) justice.
Intergenerational objective and subjective mobility and attitudes towards income differences: evidence from transition societies
Authors: Gugushvili Alexi
Published: July 2016

This article explores the association between intergenerational social mobility and attitudes towards income differences in post-socialist societies. I hypothesise that based on the psychological mechanism of self-serving bias in causal attribution, those who experience upward social mobility are more likely to support greater income differences, and that subjective intergenerational mobility has stronger association with attitudes towards income differences than objective mobility because individuals filter their objective environment in order to derive their subjective perceptions of the world and their own experiences. The described hypotheses are tested with two cross-national data sets – European Values Studies and Life in Transition Survey. The derived findings are robust to alternative statistical specifications and indicate that individuals who perceive themselves as subjectively mobile have significantly different attitudes towards income differences in comparison to non-mobile groups, but that this effect does not manifest among objectively mobile individuals.
Low cost 3D-printing used in an undergraduate project: an integrating sphere for measurement of photoluminescence quantum yield
Authors: Tomes John J , Finlayson Chris E
Published: July 2016

We report upon the exploitation of the latest 3D printing technologies to provide low-cost instrumentation solutions, for use in an undergraduate level final-year project. The project addresses prescient research issues in optoelectronics, which would otherwise be inaccessible to such undergraduate student projects. The experimental use of an integrating sphere in conjunction with a desktop spectrometer presents opportunities to use easily handled, low cost materials as a means to illustrate many areas of physics such as spectroscopy, lasers, optics, simple circuits, black body radiation and data gathering. Presented here is a 3rd year undergraduate physics project which developed a low cost (£25) method to manufacture an experimentally accurate integrating sphere by 3D printing. Details are given of both a homemade internal reflectance coating formulated from readily available materials, and a robust instrument calibration method using a tungsten bulb. The instrument is demonstrated to give accurate and reproducible experimental measurements of luminescence quantum yield of various semiconducting fluorophores, in excellent agreement with literature values.
Essence of survival analysis†
Authors: Pugh Stephanie L.
Published: July 2016

Many clinical trials are designed based on a time-to-event endpoint. Overall survival and progression-free survival are commonly used, especially in Phase II and III clinical trials. Overall survival measures the time to death from any cause, while progression-free survival measures the time to progression of the disease or death from any cause. The key distinguishing factor is that the event of interest, such as death, may not occur in all individuals, making their time to this event unknown. Survival analysis comprises of the methods used to estimate the rates associated with time-to-an-event data, compare the rates between groups, and assess how other factors impact these rates.
Interactions between warming and soil moisture increase overlap in reproductive phenology among species in an alpine meadow
Authors: zhu Juntao , Zhang Yangjian , Wang Wenfeng
Published: July 2016

Climate warming strongly influences reproductive phenology of plants in alpine and Arctic ecosystems. Here, we focus on phenological shifts caused by experimental warming in a typical alpine meadow on the Tibetan Plateau. Under soil water stress caused by warming, most plants in the alpine meadow advanced or delayed their reproductive events to be aligned with the timing of peak rainfall. As a result, warming significantly increased the temporal overlap among reproductive stages of early- and late-flowering species. In addition, we found that some species, for example the late-flowering species, were unable to produce flowers and fruits under warming with failed monsoon rains. The potentially warmer- and drier-growing seasons under climate change may similarly shift the phenological patterns and change species composition of these alpine systems.
Ageing and the cost of maintaining coloration in the Australian painted dragon
Authors: Giraudeau Mathieu , Friesen Christopher R. , Sudyka Joanna , Rollings Nicky , Whittington Camilla M. , Wilson Mark R. , Olsson Mats
Published: July 2016

There is now good evidence in several taxa that animal coloration positively reflects an individual's antioxidant capacity. However, even though telomeres, a marker of ageing, are known to be vulnerable to reactive oxygen species (ROS) attacks, no studies have ever assessed whether colour fading reflects the rate of biological ageing in any taxa. Here, we measured colour fading, telomere erosion (a measure of biological ageing) and ROS levels in painted dragons. We show that individuals that were better at maintaining their coloration during the three months of the study suffered a higher cost in terms of telomere erosion, but overall ROS levels measured at the start of the study were not significantly related to colour maintenance and telomere shortening. We therefore suggest that colour maintenance is a costly phenomenon in terms of telomere erosion, and that overall ROS levels do not seem to be a crucial component linking ornamental coloration and telomere erosion in our study system.
Bees use the taste of pollen to determine which flowers to visit
Authors: Muth Felicity , Francis Jacob S. , Leonard Anne S.
Published: July 2016

Pollen plays a dual role as both a gametophyte and a nutritional reward for pollinators. Although pollen chemistry varies across plant species, its functional significance in pollination has remained obscure, in part because little is known about how floral visitors assess it. Bees rely on pollen for protein, but whether foragers evaluate its chemistry is unclear, as it is primarily consumed by larvae. We asked whether the chemical composition of pollen influences bumblebees' foraging behaviour. Using putatively sweet and bitter pollen blends, we found that chemical composition influenced two aspects of bee behaviour relevant to plant fitness: the amount of pollen collected and the likelihood of subsequently visiting a visually similar flower. These findings offer a new perspective on the nutritional ecology of plant–pollinator interactions, as they show that pollen's taste may mediate its collection and transfer.
One size fits all? Direct evidence for the heterogeneity of genetic drift throughout the genome
Authors: Jiménez-Mena Belén , Tataru Paula , Brøndum Rasmus F. , Sahana Goutam , Guldbrandtsen Bernt , Bataillon Thomas
Published: July 2016

Effective population size (Ne) is a central parameter in population and conservation genetics. It measures the magnitude of genetic drift, rates of accumulation of inbreeding in a population, and it conditions the efficacy of selection. It is often assumed that a singleNecan account for the evolution of genomes. However, recent work provides indirect evidence for heterogeneity inNethroughout the genome. We study this by examining genome-wide diversity in the Danish Holstein cattle breed. Using the differences in allele frequencies over a single generation, we directly estimatedNeamong autosomes and smaller windows within autosomes. We found statistically significant variation inNeat both scales. However, no correlation was found between the detected regional variability inNe, and proxies for the intensity of linked selection (local recombination rate, gene density), or the presence of either past strong selection or current artificial selection on traits of economic value. Our findings call for further caution regarding the wide applicability of theNeconcept for understanding quantitatively processes such as genetic drift and accumulation of consanguinity in both natural and managed populations.