bluuebunny/crossref_metadata_2025 huggingface dataset:
Fed-EXosome: extracellular vesicles and cell–cell communication in metabolic regulation
Authors: Samuelson Isabella , Vidal-Puig Antonio J.
Published: May 2018

Extracellular vesicles (EVs) have emerged as a novel messaging system of the organism, mediating cell–cell and interorgan communication. Through their content of proteins and nucleic acids, as well as membrane proteins and lipid species, EVs can interact with and modulate the function of their target cells. The regulation of whole-body metabolism requires cross-talk between key metabolic tissues including adipose tissue (AT), the liver and skeletal muscle. Furthermore, the regulation of nutrient/energy allocation during pregnancy requires co-ordinated communication between the foetus and metabolic organs of the mother. A growing body of evidence is suggesting that EVs play a role in communication between and within key metabolic organs, both physiologically during metabolic homoeostasis but also contributing to pathophysiology during metabolic dysregulation observed in metabolic diseases such as obesity and diabetes. As obesity and its associated metabolic complications are reaching epidemic proportions, characterization of EV-mediated communication between key metabolic tissues may offer important insights into the regulation of metabolic functions during disease and offer global therapeutic opportunities. Here, we focus on the role of EVs in metabolic regulation and, in particular, EV-mediated cross-talk between cells of the AT.
Hyperspectral image super‐resolution under misaligned hybrid camera system
Authors: Lin Yonggang , Zheng Yongrong , Fu Ying , Huang Hua
Published: May 2018

Hyperspectral imaging has been widely used for agriculture, astronomy, surveillance, and so on. However, hyperspectral imaging usually suffers from low‐spatial resolution, due to the limited photons in individual bands. Recently, more hyperspectral image super‐resolution methods have been developed by fusing the low‐resolution hyperspectral image and high‐resolution RGB image, but most of them did not consider the misalignment between two input images. In this study, the authors present an effective method to restore a high‐resolution hyperspectral image from the misaligned low‐resolution hyperspectral image and high‐resolution RGB image, which exploits spectral and spatial correlation in hyperspectral and RGB images. Specifically, they employ the spectral sparsity to restore the high‐resolution hyperspectral image on the misaligned part, and then simultaneously employ spectral and spatial structure correlation to restore the high‐resolution hyperspectral image on the aligned area, which can be fused to obtain the high‐quality hyperspectral image restoration under a misaligned hybrid camera system. Experimental results show that the proposed method outperforms the state‐of‐the‐art hyperspectral image super‐resolution methods under a misaligned hybrid camera system in terms of both objective metric and subjective visual quality.
Topological alternate centrality measure capturing drug targets in the network of MAPK pathways
Authors: Md Aksam V.K. , Chandrasekaran V.M. , Pandurangan Sundaramurthy
Published: May 2018

A new centrality of the nodes in the network is proposed called alternate centrality, which can isolate effective drug targets in the complex signalling network. Alternate centrality metric defined over the network substructure (four nodes – motifs). The nodes involving in alternative activation in the motifs gain in metric values. Targeting high alternative centrality nodes hypothesised to be destructive free to the network due to their alternative activation mechanism. Overlapping and crosstalk among the gene products in the conserved network of MAPK pathways selected for the study. In silico knock‐out of high alternate centrality nodes causing rewiring in the network is investigated using MCF‐7 breast cancer cell line‐based data. Degree of top alternate centrality nodes lies between the degree of bridging and pagerank nodes. Node deletion of high alternate centrality on the centralities such as eccentricity, closeness, betweenness, stress, centroid and radiality causes low perturbation. The authors identified the following alternate centrality nodes ERK1, ERK2, MEKK2, MKK5, MKK4, MLK3, MLK2, MLK1, MEKK4, MEKK1, TAK1, P38alpha, ZAK, DLK, LZK, MLTKa/b and P38beta as efficient drug targets for breast cancer. Alternate centrality identifies effective drug targets and is free from intertwined biological processes and lethality.
Energy‐efficient and traffic‐adaptive Z‐medium access control protocol in wireless sensor networks
Authors: Li Jianpo , Su Dan , Wang Yanjiao
Published: May 2018

Both the backoff time and idle listening are the key issues affecting the performance of wireless sensor networks. Therefore, the energy‐efficient and traffic‐adaptive Z‐medium access control protocol is proposed in this study. Firstly, it avoids idle listening by setting a fixed contention window in single round to effectively improve the fairness in the backoff strategy. At the same time, it ensures the nodes with less residual energy have priority to access channel and realise the load balance. Secondly, the protocol uses the improved explicit contention notification (ECN) mechanism to reduce the energy consumption caused by sending the ECN messages repeatedly in a period of time and prolong the network lifetime. Lastly, the channel flags are introduced at the top of data frames to make an appointment on the channel so as to avoid the idle listening. Simulation results show that, when, compared with other similar algorithms, the collision rate is reduced by at least 14.2%, the time when the first node dies is prolonged by at least 135 rounds, and the average network energy consumption is reduced by at least 23%.
Facile one‐step hydrothermal syntheses of graphene oxide–MnO2 composite and their application in removing heavy metal ions
Authors: Liang Chunyan , Feng Xuezhen , Yu Jingang , Jiang Xinyu
Published: May 2018

In this work, a composite of graphene oxide (GO) supported by granulated manganese dioxide (MnO2) has been synthesised via a facile one‐step hydrothermal process and then used as adsorbent to remove heavy metal ions from aqueous solution. The morphology and surface functional groups of GO–MnO2 composite were characterised by Fourier transform infrared spectroscopy, Raman spectra, X‐ray photoelectron spectroscopy, scanning electron microscopy and thermogravimetric analysis. The results indicated that MnO2 particles were successfully inserted into graphene sheets, and the agglomeration of GO was prevented. The effects of contact time and initial concentrations of heavy metal ions on the adsorption capacity of GO–MnO2 composite were studied. The adsorption data fitted well with the pseudo‐second‐order kinetic model and the Langmuir isotherm model. The maximum adsorption capacity for Pb2+ obtained from Langmuir isotherm model was about 490 mg/g. Based on the results from the removal of four heavy metal ions from smelting wastewater and the reusability experiments, it could be deduced that GO–MnO2 composite is a potential adsorbent for environmental clean‐up.
QE of cadmium sulphide QD photodetectors
Authors: Dakhil Tahseen , Abdulalmuhsin Samir M. , Al‐Khursan Amin Habbeb
Published: May 2018

The absorption spectrum and quantum efficiency (QE) of cadmium sulphide/zinc oxide quantum dot (QD) photodetectors are studied at different QD sizes and junction depths. It is shown that doping the QD layer gives high QE. The structures studied cover the range 200–270 nm, which is important in photodetector applications. High QE was obtained at QDs with a small height, while wide QE bath was obtained at QD with enough (but not so much) radius.
Dual‐detection‐window fluorescence probe for ultra‐sensitive determination of Pb2+ based on emission‐tunable B and N co‐doped carbon dots
Authors: Cheng Qiao , He Yu , Ge Yili , Song Gongwu
Published: May 2018

In this work, 3‐aminophenylboronic acid was used as the starting materials to construct boron and nitrogen co‐doped carbon dots with tunable dual‐emission intensity at 420 and 540 nm with different excitation at 360 and 500 nm, respectively. The dual‐emission carbon dots sensor is employed for rapid and sensitive fluorescence‐enhancing detection of Pb2+. Compared with previous reported methods, their method showed better linear ranges or detection limits. Under the optimal conditions, the limit of detection of 0.9 nM for Pb2+ was reached with a wide range of 9 nM to 438 μM. The authors believe that the established method has more opportunities for application for other environmental targets.
ϵ-Efficient solutions in semi-infinite multiobjective optimization
Authors: Shitkovskaya Tatiana , Kim Do Sang
Published: May 2018

In this paper we apply some tools of nonsmooth analysis and scalarization method due to Chankong–Haimes to find ϵ-efficient solutions of semi-infinite multiobjective optimization problems (MP). We establish ϵ-optimality conditions of Karush–Kuhn–Tucker (KKT) type under Farkas–Minkowski (FM) constraint qualification by using ϵ-subdifferential concept. In addition we propose mixed type dual problem (including dual problems of Wolfe and Mond–Weir types as special cases) for ϵ-efficient solutions and investigate relationship between mentioned (MP) and its dual problem as well as establish several ϵ-duality theorems.
Translational Research in Familial Colorectal Cancer Syndromes
Authors: Ford Molly
Published: May 2018

Growing knowledge of inherited colorectal cancer syndromes has led to better surveillance and better care of this subset of patients. The most well-known entities, including Lynch syndrome and familial adenomatous polyposis, are continually being studied and with the advent of more sophisticated genetic testing, additional genetic discoveries have been made in the field of inherited cancer. This article will summarize many of the updates to both the familiar and perhaps less familiar syndromes that can lead to inherited or early-onset colorectal cancer.
Effect of Gestational and Lactational Exposure to DEHP, DINP, and DEP on Intestinal Morphology, Disaccharidases, and Alkaline Phosphatase in Rats during Postnatal Development
Authors: Kharoubi O. , Aoues A. , Bouchekara M. , Khaladi B. , Taleb M. , Setti Ahmed K.
Published: May 2018

Introduction The diesters of 1,2-benzenedicarboxylic acid (phthalic acid), commonly known as phthalates, are used primarily as plasticizers of polyvinyl chloride and as additives in consumer and personal care products.

Objective This study was designed to evaluate the impact of in utero and postnatal exposure to diisononyl phthalate (DINP), diethylhexyl phthalate (DEHP), and diethyl phthalate (DEP) on gut maturation in a Wistar rat model.

Materials and Methods Pregnant females were gavaged from day 8 of gestation through postnatal day (pd) 30 with 0 (vehicle control), DEHP (380 mg/kg/d), DINP (380 mg/kg/d), or DEP (800 mg/kg/d) dissolved in corn oil. Intestinal samples have been collected at 0, 7, 14, 21, and 30 pd for histological and biochemical analysis. The mitotic index has been evaluated based on the expression of Ki-67 antigen.

Results All tested phthalate treatments have significantly decreased the body as well as the organ's weight (p < 0.001). DINP exposure resulted in severe villous atrophy, while DEHP treated group was characterized by lymphoepithelial lesions. In addition, a significant decrease of the Ki-67 proliferation index was observed in the youngest rats (0 and 7 days) upon the various treatments (p < 0.0001), whereas at day 30, an increased numbers of Ki-67 positive cells were observed in DEHP and DEP but bot DINP group. Lactase and sucrase activities were inhibited by DEP in contrast to DINP and DEHP which increased enzymes activity (p < 0.05).

Conclusion Our results suggest that exposure to phthalates during gestational and lactational phases negatively impacts the development of the small intestine.
Integrating sphere based reflectance measurements for small-area semiconductor samples
Authors: Saylan S. , Howells C. T. , Dahlem M. S.
Published: May 2018

This article describes a method that enables reflectance spectroscopy of small semiconductor samples using an integrating sphere, without the use of additional optical elements. We employed an inexpensive sample holder to measure the reflectance of different samples through 2-, 3-, and 4.5-mm-diameter apertures and applied a mathematical formulation to remove the bias from the measured spectra caused by illumination of the holder. Using the proposed method, the reflectance of samples fabricated using expensive or rare materials and/or low-throughput processes can be measured. It can also be incorporated to infer the internal quantum efficiency of small-area, research-level solar cells. Moreover, small samples that reflect light at large angles and develop scattering may also be measured reliably, by virtue of an integrating sphere insensitive to directionalities.
Examining the influence of grain size on radiation tolerance in the nanocrystalline regime
Authors: Barr Christopher M. , Li Nan , Boyce Brad L. , Hattar Khalid
Published: May 2018

Nanocrystalline materials have been proposed as superior radiation tolerant materials in comparison to coarse grain counterparts. However, there is still a limited understanding whether a particular nanocrystalline grain size is required to obtain significant improvements in key deleterious effects resulting from energetic irradiation. This work employs the use of in-situ heavy ion irradiation transmission electron microscopy experiments coupled with quantitative defect characterization and precession electron diffraction to explore the sensitivity of defect size and density within the nanocrystalline regime in platinum. Under the explored experimental conditions, no significant change in either the defect size or density between grain sizes of 20 and 100 nm was observed. Furthermore, the in-situ transmission electron microscopy irradiations illustrate stable sessile defect clusters of 1–3 nm adjacent to most grain boundaries, which are traditionally treated as strong defect sinks. The stability of these sessile defects observed in-situ in small, 20–40 nm, grains is the proposed primary mechanism for a lack of defect density trends. This scaling breakdown in radiation improvement with decreasing grain size has practical importance on nanoscale grain boundary engineering approaches for proposed radiation tolerant alloys.
Superconducting ECR ion source: From 24-28 GHz SECRAL to 45 GHz fourth generation ECR
Authors: Zhao H. W. , Sun L. T. , Guo J. W. , Zhang W. H. , Lu W. , Wu W. , Wu B. M. , Sabbi G. , Juchno M. , Hafalia A. , Ravaioli E. , Xie D. Z.
Published: May 2018

The development of superconducting ECR source with higher magnetic fields and higher microwave frequency is the most straight forward path to achieve higher beam intensity and higher charge state performance. SECRAL, a superconducting third generation ECR ion source, is designed for 24-28 GHz microwave frequency operation with an innovative magnet configuration of sextupole coils located outside the three solenoids. SECRAL at 24 GHz has already produced a number of record beam intensities, such as 40Ar12+ 1.4 emA, 129Xe26+ 1.1 emA, 129Xe30+ 0.36 emA, and 209Bi31+ 0.68 emA. SECRAL-II, an upgraded version of SECRAL, was built successfully in less than 3 years and has recently been commissioned at full power of a 28 GHz gyrotron and three-frequency heating (28 + 45 + 18 GHz). New record beam intensities for highly charged ion production have been achieved, such as 620 eμA 40Ar16+, 15 eμA 40Ar18+, 146 eμA 86Kr28+, 0.5 eμA 86Kr33+, 53 eμA 129Xe38+, and 17 eμA 129Xe42+. Recent beam test results at SECRAL and SECRAL II have demonstrated that the production of more intense highly charged heavy ion beams needs higher microwave power and higher frequency, as the scaling law predicted. A 45 GHz superconducting ECR ion source FECR (a first fourth generation ECR ion source) is being built at IMP. FECR will be the world’s first Nb3Sn superconducting-magnet-based ECR ion source with 6.5 T axial mirror field, 3.5 T sextupole field on the plasma chamber inner wall, and 20 kW at a 45 GHz microwave coupling system. This paper will focus on SECRAL performance studies at 24-28 GHz and technical design of 45 GHz FECR, which demonstrates a technical path for highly charged ion beam production from 24 to 28 GHz SECRAL to 45 GHz FECR.
Graphene as current spreading layer on AlGaInP light emitting diodes
Authors: Guo Xia , Feng Yajie , Liu Qiaoli , Hu Anqi , He Xiaoying , Hu Zonghai
Published: May 2018

Due to high transmittance and high mobility, graphene is one of the promising candidates for a current spreading layer, which is crucial to light emitting diode (LED) performance. In this paper, improved AlGaInP LED performance was reported after graphene was applied on the GaP surface. Due to its lowered work function difference than with the GaN material, the electrical properties remain the same without additional voltage bias. The light output power is enhanced by about 40% under the current injection of 5 mA at room temperature, which was confirmed by the light emission profile analysis in this study. Such results indicate that raphene is a promising candidate as a current spreading layer under low current injection.
Integrated gas hydrate-membrane system for natural gas purification
Authors: Warrier Pramod , Naveed Khan M. , Carreon Moises A. , Peters Cornelis J. , Koh Carolyn A.
Published: May 2018

Significant efforts are being made to make natural gas processing energy-efficient and environmentally friendly by utilizing membrane based separation processes. While membranes (polymer/zeolite/metal-organic framework) are effective in separating CO2 and N2 from CH4, their separation performance is negatively affected when natural gas contains high concentrations of higher hydrocarbons (propane, butane, etc.) and H2S. Interestingly, higher hydrocarbons and H2S form gas (clathrate) hydrates at much milder conditions compared to CH4, CO2, and N2 and could thus act as a separation step before membranes. In this perspective, gas separation using membranes and gas hydrates is briefly reviewed, and the challenges of developing an integrated gas hydrate-membrane process are discussed. Such a process could be an energy efficient approach to reduce the costs associated with natural gas purification. The proposed system can also serve as a model for other challenging molecular gas separations relevant to the energy and environmental arenas, including flue gas treatment and hydrogen purification.
β3-tripeptides act as sticky ends to self-assemble into a bioscaffold
Authors: Del Borgo Mark P. , Kulkarni Ketav , Tonta Mary A. , Ratcliffe Jessie L. , Seoudi Rania , Mechler Adam I. , Perlmutter Patrick , Parkington Helena C. , Aguilar Marie-Isabel
Published: May 2018

Peptides comprised entirely of β3-amino acids, commonly referred to as β-foldamers, have been shown to self-assemble into a range of materials. Previously, β-foldamers have been functionalised via various side chain chemistries to introduce function to these materials without perturbation of the self-assembly motif. Here, we show that insertion of both rigid and flexible molecules into the backbone structure of the β-foldamer did not disturb the self-assembly, provided that the molecule is positioned between two β3-tripeptides. These hybrid β3-peptide flanked molecules self-assembled into a range of structures. α-Arginlyglycylaspartic acid (RGD), a commonly used cell attachment motif derived from fibronectin in the extracellular matrix, was incorporated into the peptide sequence in order to form a biomimetic scaffold that would support neuronal cell growth. The RGD-containing sequence formed the desired mesh-like scaffold but did not encourage neuronal growth, possibly due to over-stimulation with RGD. Mixing the RGD peptide with a β-foldamer without the RGD sequence produced a well-defined scaffold that successfully encouraged the growth of neurons and enabled neuronal electrical functionality. These results indicate that β3-tripeptides can form distinct self-assembly units separated by a linker and can form fibrous assemblies. The linkers within the peptide sequence can be composed of a bioactive α-peptide and tuned to provide a biocompatible scaffold.
Cathodoluminescence studies of chevron features in semi-polar (112¯2) InGaN/GaN multiple quantum well structures
Authors: Brasser C. , Bruckbauer J. , Gong Y. , Jiu L. , Bai J. , Warzecha M. , Edwards P. R. , Wang T. , Martin R. W.
Published: May 2018

Epitaxial overgrowth of semi-polar III-nitride layers and devices often leads to arrowhead-shaped surface features, referred to as chevrons. We report on a study into the optical, structural, and electrical properties of these features occurring in two very different semi-polar structures, a blue-emitting multiple quantum well structure, and an amber-emitting light-emitting diode. Cathodoluminescence (CL) hyperspectral imaging has highlighted shifts in their emission energy, occurring in the region of the chevron. These variations are due to different semi-polar planes introduced in the chevron arms resulting in a lack of uniformity in the InN incorporation across samples, and the disruption of the structure which could cause a narrowing of the quantum wells (QWs) in this region. Atomic force microscopy has revealed that chevrons can penetrate over 150 nm into the sample and quench light emission from the active layers. The dominance of non-radiative recombination in the chevron region was exposed by simultaneous measurement of CL and the electron beam-induced current. Overall, these results provide an overview of the nature and impact of chevrons on the luminescence of semi-polar devices.
Hot LO-phonon limited electron transport in ZnO/MgZnO channels
Authors: Šermukšnis E. , Liberis J. , Matulionis A. , Avrutin V. , Toporkov M. , Özgür Ü. , Morkoç H.
Published: May 2018

High-field electron transport in two-dimensional channels at ZnO/MgZnO heterointerfaces has been investigated experimentally. Pulsed current–voltage (I–V) and microwave noise measurements used voltage pulse widths down to 30 ns and electric fields up to 100 kV/cm. The samples investigated featured electron densities in the range of 4.2–6.5 × 1012 cm−2, and room temperature mobilities of 142–185 cm2/V s. The pulsed nature of the applied field ensured negligible, if any, change in the electron density, thereby allowing velocity extraction from current with confidence. The highest extracted electron drift velocity of ∼0.5 × 107 cm/s is somewhat smaller than that estimated for bulk ZnO; this difference is explained in the framework of longitudinal optical phonon accumulation (hot-phonon effect). The microwave noise data allowed us to rule out the effect of excess acoustic phonon temperature caused by Joule heating. Real-space transfer of hot electrons into the wider bandgap MgZnO layer was observed to be a limiting factor in samples with a high Mg content (48%), due to phase segregation and the associated local lowering of the potential barrier.
Improvement of gas-adsorption performances of Ag-functionalized monolayer MoS2 surfaces: A first-principles study
Authors: Song Jian , Lou Huan
Published: May 2018

Investigations of the adsorptions of representative gases (NO2, NH3, H2S, SO2, CO, and HCHO) on different Ag-functionalized monolayer MoS2 surfaces were performed by first principles methods. The adsorption configurations, adsorption energies, electronic structure properties, and charge transfer were calculated, and the results show that the adsorption activities to gases of monolayer MoS2 are dramatically enhanced by the Ag-modification. The Ag-modified perfect MoS2 (Ag-P) and MoS2 with S-vacancy (Ag-Vs) substrates exhibit a more superior adsorption activity to NO2 than other gases, which is consistent with the experimental reports. The charge transfer processes of different molecules adsorbed on different surfaces exhibit various characteristics, with potential benefits to gas selectivity. For instance, the NO2 and SO2 obtain more electrons from both Ag-P and Ag-Vs substrates but the NH3 and H2S donate more electrons to materials than others. In addition, the CO and HCHO possess totally opposite charge transfer directs on both substrates, respectively. The BS and PDOS calculations show that semiconductor types of gas/Ag-MoS2 systems are more determined by the metal-functionalization of material, and the directs and numbers of charge transfer process between gases and adsorbents can cause the increase or decline of material resistance theoretically, which is helpful to gas detection and distinction. The further analysis indicates suitable co-operation between the gain-lost electron ability of gas and metallicity of featuring metal might adjust the resistivity of complex and contribute to new thought for metal-functionalization. Our works provide new valuable ideas and theoretical foundation for the potential improvement of MoS2-based gas sensor performances, such as sensitivity and selectivity.
Charge transfer excitations from exact and approximate ensemble Kohn-Sham theory
Authors: Gould Tim , Kronik Leeor , Pittalis Stefano
Published: May 2018

By studying the lowest excitations of an exactly solvable one-dimensional soft-Coulomb molecular model, we show that components of Kohn-Sham ensembles can be used to describe charge transfer processes. Furthermore, we compute the approximate excitation energies obtained by using the exact ensemble densities in the recently formulated ensemble Hartree-exchange theory [T. Gould and S. Pittalis, Phys. Rev. Lett. 119, 243001 (2017)]. Remarkably, our results show that triplet excitations are accurately reproduced across a dissociation curve in all cases tested, even in systems where ground state energies are poor due to strong static correlations. Singlet excitations exhibit larger deviations from exact results but are still reproduced semi-quantitatively.
Electrical transport properties and giant baroresistance effect at martensitic transformation of Ni43.7Fe5.3Mn35.4In15.6 Heusler alloy
Authors: Zhang Yuanlei , He Xijia , Li Zhe , Xu Kun , Liu Changqin , Huang Yinsheng , Jing Chao
Published: May 2018

The electrical transport properties at martensitic transformation (MT) in polycrystalline Ni43.7Fe5.3Mn35.4In15.6 have been intensively investigated under different hydrostatic pressures. For this alloy, the experimental results show that applying a higher hydrostatic pressure can convert its MT from the metamagnetic type into the paramagnetic type. It provides a unique opportunity to separate the relative contributions of electron-spin and electron-lattice scatterings across the metamagnetic MT based on the dynamical Clausius-Clapeyron equation, which delivers a deeper insight into the resistivity change of metamagnetic MT for the Mn-rich Ni-Mn based Heusler alloys. In addition, the studied alloy also reveals a giant positive baroresistance (BR) effect with a saturated value of 115% at 242 K. This performance originates from the combined effect of electron-spin and electron-lattice scatterings associated with a prominent hydrostatic pressure-induced MT, which contribute 46% and 69% to the overall BR ratio, respectively.
Evidence for existence of functional monoclinic phase in sodium niobate based solid solution by powder neutron diffraction
Authors: Mishra S. K. , Jauhari Mrinal , Mittal R. , Krishna P. S. R. , Reddy V. R. , Chaplot S. L.
Published: May 2018

We have carried out systematic temperature-dependent neutron diffraction measurements in conjunction with dielectric spectroscopy from 6 to 300 K for sodium niobate based compounds (1-x) NaNbO3-xBaTiO3 (NNBTx). The dielectric constant is measured as a function of both temperature and frequency. It shows an anomaly at different temperatures in cooling and heating cycles and exhibits a large thermal hysteresis of ∼150 K for the composition x = 0.03. The dielectric constant is found to be dispersive in nature and suggests a relaxor ferroelectric behavior. In order to explore structural changes as a function of temperature, we analyzed the powder neutron diffraction data for the compositions x = 0.03 and 0.05. Drastic changes are observed in the powder profiles near 2θ ∼ 30.6°, 32.1°, and 34.6° in the diffraction pattern below 200 K during cooling and above 190 K in heating cycles, respectively. The disappearance of superlattice reflection and splitting in main perovskite peaks provide a signature for structural phase transition. We observed stabilization of a monoclinic phase (Cc) at low temperature. This monoclinic phase is believed to provide a flexible polarization rotation and considered to be directly linked to the high performance piezoelectricity in materials. The thermal hysteresis for composition x = 0.03 is larger than that for x = 0.05. This suggests that the addition of BaTiO3 to NaNbO3 suppresses the thermal hysteresis. It is also observed that the structural phase transition temperature decreases upon increasing the dopant concentration.
Impurity seeding for suppression of the near scrape-off layer heat flux feature in tokamak limited plasmas
Authors: Nespoli F. , Labit B. , Furno I. , Theiler C. , Sheikh U. A. , Tsui C. K. , Boedo J. A. ,   TCV Team
Published: May 2018

In inboard-limited plasmas, foreseen to be used in future fusion reactor start-up and ramp down phases, the Scrape-Off Layer (SOL) exhibits two regions: the “near” and “far” SOL. The steep radial gradient of the parallel heat flux associated with the near SOL can result in excessive thermal loads onto the solid surfaces, damaging them and/or limiting the operational space of a fusion reactor. In this article, leveraging the results presented in the study by F. Nespoli et al. [Nucl. Fusion 57, 126029 (2017)], we propose a technique for the mitigation and suppression of the near SOL heat flux feature by impurity seeding. The first successful experimental results from the TCV tokamak are presented and discussed.
A polarization independent electromagnetically induced transparency-like metamaterial with large group delay and delay-bandwidth product
Authors: Bagci Fulya , Akaoglu Baris
Published: May 2018

In this study, a classical analogue of electromagnetically induced transparency (EIT) that is completely independent of the polarization direction of the incident waves is numerically and experimentally demonstrated. The unit cell of the employed planar symmetric metamaterial structure consists of one square ring resonator and four split ring resonators (SRRs). Two different designs are implemented in order to achieve a narrow-band and wide-band EIT-like response. In the unit cell design, a square ring resonator is shown to serve as a bright resonator, whereas the SRRs behave as a quasi-dark resonator, for the narrow-band (0.55 GHz full-width at half-maximum bandwidth around 5 GHz) and wide-band (1.35 GHz full-width at half-maximum bandwidth around 5.7 GHz) EIT-like metamaterials. The observed EIT-like transmission phenomenon is theoretically explained by a coupled-oscillator model. Within the transmission window, steep changes of the phase result in high group delays and the delay-bandwidth products reach 0.45 for the wide-band EIT-like metamaterial. Furthermore, it has been demonstrated that the bandwidth and group delay of the EIT-like band can be controlled by changing the incidence angle of electromagnetic waves. These features enable the proposed metamaterials to achieve potential applications in filtering, switching, data storing, and sensing.
Enhanced inductance in laminated multilayer magnetic planar inductor for sensitive magnetic field detection
Authors: Wang Yao , Wen Yumei , Song Fapeng , Li Ping , Yu Shumin
Published: May 2018

The authors reported laminated multilayer magnetic planar inductors for sensitive magnetic field detection, which consist of two serially connected sandwich planar inductors (i.e., FeCuNbSiB/micro planar coil/FeCuNbSiB/micro planar coil/FeCuNbSiB). When ac current is applied to coils, the greatly increased inductance by the incorporated high permeability magnetic material and enlarged mutual-inductance among coils significantly improve the sensor sensitivity to the dc magnetic field. The demagnetizing field is also found to affect the performance severely when the shape and the number of magnetic layers vary. The investigation indicates that the proposed laminate can provide an inductance ratio of 665% at the frequency of 1 kHz. By connecting the sensor with a capacitor, the sensor output with varying dc magnetic fields is obtained by tuning the resonant frequency shift. The study indicates that the proposed sensor can provide a sensitivity of about 3.57 kHz/Oe with a resolution of 28 nT between 2 Oe and 60 Oe, which outperforms most of the magnetic sensors with frequency shifting output.
Quasi-self-trapped Frenkel-exciton near-UV luminescence with large Stokes shift in wide-bandgap Cs4PbCl6 nanocrystals
Authors: Zhang Yumeng , Fan Baolu , Liu Yuzhen , Li Hongxia , Deng Kaiming , Fan Jiyang
Published: May 2018

Inorganic lead halide perovskite nanocrystals (NCs) have attracted great interest owing to their superior luminescence and optoelectronic properties. In comparison to cubic CsPbX3 (X = Cl, Br, or I) that has visible luminescence, trigonal Cs4PbX6 has a much larger bandgap and distinct optical properties. Little has been known about the luminescence properties of the Cs4PbX6 NCs. In this study, we synthesize the well-crystallized Cs4PbCl6 NCs with sizes of 2.2–11.8 nm, which exhibit stable and near-UV luminescence (with a lifetime of 19.7–24.2 ns) with a remarkable quantum confinement effect at room temperature. In comparison to the negligible Stokes shift in the CsPbCl3 NCs, the Stokes shift of the Cs4PbCl6 NCs is very large (0.91 eV). The experimental results in combination with the first-principles calculations reveal that the near-UV luminescence of the Cs4PbCl6 NCs stems from the Frenkel excitons self-trapped in the isolated PbCl64– octahedrons. This is different from the CsPbCl3 NCs whose luminescence originates from the free Wannier excitons. The theoretical model based on the lattice relaxation is proposed to account for the large Stokes shift and its abnormal decrease with the decreasing particle size.
Transition regime from step-flow to step-bunching in the growth of epitaxial SrRuO3 on (001) SrTiO3
Authors: Gura Anna , Bertino Giulia , Bein Benjamin , Dawber Matthew
Published: May 2018

We present a study of the surface morphology of SrRuO3 thin films grown on TiO2 terminated (001) SrTiO3 substrates using an off-axis RF magnetron sputtering deposition technique. We investigated the step bunching formation and the evolution of the films by varying deposition parameters. The thin films were characterized using atomic force microscopy methods, allowing us to study the various growth regimes of SrRuO3 as a function of the growth parameters. We observe a strong influence of both the miscut angle and growth temperature on the evolution of the SrRuO3 surface morphology. In addition, a thickness dependence is present. Remarkably, the formation of a smooth, regular, and uniform “fish-skin” structure at the step-bunch transition is observed. The fish-skin morphology results from the merging of 2D flat islands predicted by previous models. The direct observation of surface evolution allows us to better understand the different growth regimes of SrRuO3 thin films.
A numerical study of the segregation phenomenon of lognormal particle size distributions in the rotating drum
Authors: Yang Shiliang , Sun Yuhao , Zhao Ya , Chew Jia Wei
Published: May 2018

Granular materials are mostly polydisperse, which gives rise to phenomena such as segregation that has no monodisperse counterpart. The discrete element method is applied to simulate lognormal particle size distributions (PSDs) with the same arithmetic mean particle diameter but different PSD widths in a three-dimensional rotating drum operating in the rolling regime. Despite having the same mean particle diameter, as the PSD width of the lognormal PSDs increases, (i) the steady-state mixing index, the total kinetic energy, the ratio of the active region depth to the total bed depth, the mass fraction in the active region, the steady-state active-passive mass-based exchanging rate, and the mean solid residence time (SRT) of the particles in the active region increase, while (ii) the steady-state gyration radius, the streamwise velocity, and the SRT in the passive region decrease. Collectively, these highlight the need for more understanding of the effect of PSD width on the granular flow behavior in the rotating drum operating in the rolling flow regime.
Influence of surface crystal-orientation on transfer doping of V2O5/H-terminated diamond
Authors: Verona C. , Arciprete F. , Foffi M. , Limiti E. , Marinelli M. , Placidi E. , Prestopino G. , Verona Rinati G.
Published: May 2018

Surface transfer doping of hydrogen-terminated diamond induced by high work function V2O5 oxide was investigated on samples with (100) and (111) surface crystal-orientations. An enhancement of sheet hole density and a decrease in sheet resistance were obtained in the case of (111) diamond as compared to (100). In particular, a sheet resistance as low as 1.8 kΩ/◻ and a sheet hole concentration of 1.1 × 1014 cm−2 were obtained by Hall effect measurements for V2O5/H-(111) oriented diamonds, the latter being about twice as high as the one obtained for V2O5/H-(100) oriented diamonds. This was confirmed by capacitance-voltage measurements on metal/V2O5/H-diamond diodes fabricated on the investigated samples, also resulting in the determination of the depth profiles of hole accumulation layers at the diamond surface. X-ray photoelectron spectroscopy measurements of the C1s core level shift were used to determine the differences in surface band bending, leading to a different hole accumulation layer formation efficiency at the V2O5/H-diamond interface. An upward band bending of 0.7 eV and 0.3 eV in response to the surface transfer doping induced by a 10 Å thick V2O5 layer was measured for (111) and (100) diamond surfaces, respectively. This is a further confirmation that V2O5 is more effective in surface transfer doping for H-(111) oriented diamond. The obtained results are very promising in view of the development of high-power metal oxide field effect transistors based on the H-diamond surface.
Evolution from successive phase transitions to “morphotropic phase boundary” in BaTiO3-based ferroelectrics
Authors: Zhou Chao , Ke Xiaoqin , Yao Yonggang , Yang Sen , Ji Yuanchao , Liu Wenfeng , Yang Yaodong , Zhang Lixue , Hao Yanshuang , Ren Shuai , Zhang Le , Ren Xiaobing
Published: May 2018

Obtaining superior physical properties for ferroic materials by manipulating the phase transitions is a key concern in solid state physics. Here, we investigated the dielectric permittivity, piezoelectric coefficient d33, storage modulus, and crystal symmetry of (1-x)Ba(Ti0.8Zr0.2)O3-x(Ba1−yCay)TiO3 (BZT-xBCyT) systems to demonstrate the gradual evolution process from successive phase transitions in BaTiO3 to the morphotropic phase boundary (MPB) regime in BZT-xBC0.3T. Furthermore, we analysed with a Landau-type theoretical model to show that the high field-sensitive response (dielectric permittivity) originates from a small polarization anisotropy and low energy barrier at the quadruple point. Together, the intermediate orthorhombic phase regime and the tetragonal-orthorhombic and orthorhombic-rhombohedral phase boundaries constitute the MPB. Our work not only reconciles the arguments regarding whether the structural state around the MPB corresponds to a single-phase regime or a multiple-phase-coexistence regime but also suggests an effective method to design high-performance functional ferroic materials by tailoring the successive phase transitions.
Field-induced structural control of COx molecules adsorbed on graphene
Authors: Matsubara Manaho , Okada Susumu
Published: May 2018

Using the density functional theory combined with both the van der Waals correction and the effective screening medium method, we investigate the energetics and electronic structures of CO and CO2 molecules adsorbed on graphene surfaces in the field-effect-transistor structure with respect to the external electric field by the excess electrons/holes. The binding energies of CO and CO2 molecules to graphene monotonically increase with increasing hole and electron concentrations. The increase occurs regardless of the molecular conformations to graphene and the counter electrode, indicating that the carrier injection substantially enhances the molecular adsorption on graphene. Injected carriers also modulate the stable molecular conformation, which is metastable in the absence of an electric field.
Jupiter’s wind bands have deep roots
Authors: Grant Andrew
Published: May 2018

Gravity measurements by NASA’s Juno spacecraft resolve a long-standing debate about the structure of gas giants.
DOE prepares major upgrade of its lithium-6 operations
Authors: Kramer David
Published: May 2018

The isotope is used to make and sustain nuclear warheads. Recycling it from old warheads may not meet demand.
Making archaeology cool with dry-ice cleaning
Authors: Hoffman William
Published: May 2018

Conservators can use the conceptually simple technology to remove corrosion on wrought-iron objects such as the gun turret recovered from the wreck of the USS Monitor.
Stimulation of cyclic electron flow around PSI as a response to the combined stress of high light and high temperature in grape leaves
Authors: Sun Yongjiang , Gao Yulu , Wang Hui , Yang Xinghong , Zhai Heng , Du Yuanpeng
Published: May 2018

Changes in cyclic electron ﬂow (CEF) around PSI activity after exposing grape (Vitis vinifera L.) seedling leaves to the combined stress of high temperature (HT) and high light (HL) were investigated. The PSII potential quantum efﬁciency (Fv/Fm) decreased significantly under exposure to HT, and this decrease was greater when HT was combined with HL, whereas the PSI activity maintained stable. HT enhanced CEF mediated by NAD(P)H dehydrogenase remarkably. Compared with the control leaves, the half-time of P700+ re-reduction decreased during the HT treatment; this decrease was even more pronounced under the combined stress, implying signiﬁcantly enhanced CEF as a result of the treatment. However, the heat-induced increase in nonphotochemical quenching (NPQ) was greater under HL, accompanied by a greater enhancement in high-energy state quenching. These results suggest that the combined stress of HT and HL resulted in severe PSII photoinhibition, whereas CEF showed plasticity in its response to environmental stress and played an important role in PSII and PSI photoprotection through accelerating generation of the thylakoid proton gradient and the induction of NPQ.
Relationship power and HIV risk among young Black men who have sex with men in the Southern United States
Authors: Ricks JaNelle M. , Crosby Richard A. , Mena Leandro
Published: May 2018

Background The purpose of this study was to examine the impact of relationship power on HIV risk behaviour among young Black men who have sex with men (MSM) in the Southern US. Methods: Data from 425 Black/African American males aged 18–29 years who reported recent anal intercourse with a male partner were analysed. Five selected measures of relationship power were tested for correlation and association with protected receptive anal intercourse using contingency tables and logistic regression analysis. Results: Acts of 100% protected receptive anal intercourse were common (n = 277, 65.2%). Men who reported low barriers to condom negotiation were significantly more likely to report protected acts (P < 0.001). Men who reported 100% protected acts were less likely to report financial dependence on male sexual partners and serosorting behaviour (12.0% vs 20.7%, P = 0.02; 31.5% vs 49.8%, P < 0.001 respectively). Conclusion: Future efforts should further examine the role of relationship power in HIV risk among young Black MSM, including the intersection of individual, dyadic and social-structure risks.
A review of potential sources of revenue for sustaining fisheries co-management activities in the southern Lake Malawi, Mangochi district
Authors: Njaya Friday , Donda Steve , Hara Mafaniso
Published: May 2018

This article seeks to review and identify potential sources of funds for implementation of planned activities within a fisheries co-management arrangement in the southern Lake Malawi, Mangochi District. In this review, we use secondary sources on fisheries co-management at both national and international levels. With adoption of the co-management or participatory fisheries management as it is alternatively called in Malawi, consideration of sustainable financing mechanisms is essential for implementation of planned activities by the local fisheries management authorities and beach village committees within a decentralization framework. Potential revenue sources include development of a fisheries fund and establishment of a benefit sharing mechanism with reference to a district user fee. Other sources include fees charged for conducting fisheries research on the lake, membership fee for joining beach village committees, levies on fish marketing and fees charged for use of facilities especially jetties, store rooms and fish processing facilities on a beach. The revenue collection is recommended as one of the incentives for co-management partners to ensure implementation of activities like law enforcement, licensing, training, community outreach services and research. We recommend that the legal provisions on the establishment of a fisheries fund and revenue sharing be implemented to ensure availability of funds for the fisheries sector. In addition, the existing by-laws with outlined financing mechanisms should be approved by the appropriate authorities.
Survey of miRNA-miRNA cooperative regulation principles across cancer types
Authors: Shao Tingting , Wang Guangjuan , Chen Hong , Xie Yunjin , Jin Xiyun , Bai Jing , Xu Juan , Li Xia , Huang Jian , Jin Yan , Li Yongsheng
Published: May 2018

Cooperative regulation among multiple microRNAs (miRNAs) is a complex type of posttranscriptional regulation in human; however, the global view of the system-level regulatory principles across cancers is still unclear. Here, we investigated miRNA-miRNA cooperative regulatory landscape across 18 cancer types and summarized the regulatory principles of miRNAs. The miRNA-miRNA cooperative pan-cancer network exhibited a scale-free and modular architecture. Cancer types with similar tissue origins had high similarity in cooperative network structure and expression of cooperative miRNA pairs. In addition, cooperative miRNAs showed divergent properties, including higher expression, greater expression variation and a stronger regulatory strength towards targets and were likely to regulate cancer hallmark-related functions. We found a marked rewiring of miRNA-miRNA cooperation between various cancers and revealed conserved and rewired network miRNA hubs. We further identified the common hubs, cancer-specific hubs and other hubs, which tend to target known anticancer drug targets. Finally, miRNA cooperative modules were found to be associated with patient survival in several cancer types. Our study highlights the potential of pan-cancer miRNA-miRNA cooperative regulation as a novel paradigm that may aid in the discovery of tumorigenesis mechanisms and development of anticancer drugs.