bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of biological activity of gonadotropins hCG and FSH by Förster resonance energy transfer based biosensors
Authors: Mazina Olga , Allikalt Anni , Tapanainen Juha S. , Salumets Andres , Rinken Ago
Published: February 2017

Determination of biological activity of gonadotropin hormones is essential in reproductive medicine and pharmaceutical manufacturing of the hormonal preparations. The aim of the study was to adopt a G-protein coupled receptor (GPCR)-mediated signal transduction pathway based assay for quantification of biological activity of gonadotropins. We focussed on studying human chorionic gonadotropin (hCG) and follicle-stimulating hormone (FSH), as these hormones are widely used in clinical practice. Receptor-specific changes in cellular cyclic adenosine monophosphate (cAMP, second messenger in GPCR signalling) were monitored by a Förster resonance energy transfer (FRET) biosensor protein TEpacVV in living cells upon activation of the relevant gonadotropin receptor. The BacMam gene delivery system was used for biosensor protein expression in target cells. In the developed assay only biologically active hormones initiated GPCR-mediated cellular signalling. High assay sensitivities were achieved for detection of hCG (limit of detection, LOD: 5 pM) and FSH (LOD: 100 pM). Even the small-scale conformational changes caused by thermal inactivation and reducing the biological activity of the hormones were registered. In conclusion, the proposed assay is suitable for quantification of biological activity of gonadotropins and is a good alternative to antibody- and animal-testing-based assays used in pharmaceutical industry and clinical research.
The antimicrobial molecule trappin-2/elafin has anti-parasitic properties and is protective in vivo in a murine model of cerebral malaria
Authors: Roussilhon Christian , Bang Gilles , Bastaert Fabien , Solhonne Brigitte , Garcia-Verdugo Ignacio , Peronet Roger , Druilhe Pierre , Sakuntabhai Anavaj , Mecheri Salaheddine , Sallenave Jean-Michel
Published: February 2017

According to the WHO, and despite reduction in mortality rates, there were an estimated 438 000 malaria deaths in 2015. Therefore new antimalarials capable of limiting organ damage are still required. We show that systemic and lung adenovirus (Ad)-mediated over-expression of trappin-2 (T-2) an antibacterial molecule with anti-inflammatory activity, increased mice survival following infection with the cerebral malaria-inducingPlasmodium bergheiANKA (PbANKA) strain. Systemically, T-2 reducedPbANKA sequestration in spleen, lung, liver and brain, associated with a decrease in pro-inflammatory cytokines (eg TNF-α in spleen and lung) and an increase in IL-10 production in the lung. Similarly, local lung instillation of Ad-T-2 resulted in a reduced organ parasite sequestration and a shift towards an anti-inflammatory/repair response, potentially implicating monocytes in the protective phenotype. Relatedly, we demonstratedin vitrothat human monocytes incubated withPlasmodium falciparum-infected red blood cells (Pf-iRBCs) and IgGs from hyper-immune African human sera produced T-2 and that the latter colocalized with merozoites and inhibitedPfmultiplication. This array of data argues for the first time for the potential therapeutic usefulness of this host defense peptide in human malaria patients, with the aim to limit acute lung injury and respiratory distress syndrom often observed during malaria episodes.
Erratum: Biogenic synthesis of Zinc oxide nanostructures from Nigella sativa seed: Prospective role as food packaging material inhibiting broad-spectrum quorum sensing and biofilm
Authors: Al-Shabib Nasser A. , Husain Fohad Mabood , Ahmed Faheem , Khan Rais Ahmad , Ahmad Iqbal , Alsharaeh Edreese , Khan Mohd Shahnawaz , Hussain Afzal , Rehman Md Tabish , Yusuf Mohammad , Hassan Iftekhar , Khan Javed Masood , Ashraf Ghulam Md , Alsalme Ali , Al-Ajmi Mohamed F. , Tarasov Vadim V. , Aliev Gjumrakch
Published: February 2017

Scientific Reports 6: Article number: 36761; published online: 05 December 2016; updated: 09 February 2017 The original version of this Article contained a typographical error in the spelling of Ali Alsalme, which was incorrectly given as Ali Mohammed Alsalme. In addition, Mohamed F. Al-Ajmi was incorrectly affiliated to “Protein Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh-11451, Kingdom of Saudi Arabia”.
Long-term nitrogen fertilization decreased the abundance of inorganic phosphate solubilizing bacteria in an alkaline soil
Authors: Zheng Bang-Xiao , Hao Xiu-Li , Ding Kai , Zhou Guo-Wei , Chen Qing-Lin , Zhang Jia-Bao , Zhu Yong-Guan
Published: February 2017

Inorganic phosphate solubilizing bacteria (iPSB) are essential to facilitate phosphorus (P) mobilization in alkaline soil, however, the phylogenetic structure of iPSB communities remains poorly characterized. Thus, we use a reference iPSB database to analyze the distribution of iPSB communities based on 16S rRNA gene illumina sequencing. Additionally, a noval pqqC primer was developed to quantify iPSB abundance. In our study, an alkaline soil with 27-year fertilization treatment was selected. The percentage of iPSB was 1.10~2.87% per sample, and the dominant iPSB genera were closely related to Arthrobacter, Bacillus, Brevibacterium and Streptomyces. Long-term P fertilization had no significant effect on the abundance of iPSB communities. Rather than P and potassium (K) additions, long-term nitrogen (N) fertilization decreased the iPSB abundance, which was validated by reduced relative abundance of pqqC gene (pqqC/16S). The decreased iPSB abundance was strongly related to pH decline and total N increase, revealing that the long-term N additions may cause pH decline and subsequent P releases relatively decreasing the demands of the iPSB community. The methodology and understanding obtained here provides insights into the ecology of inorganic P solubilizers and how to manipulate for better P use efficiency.
Structural and Functional insights into the catalytic mechanism of the Type II NADH:quinone oxidoreductase family
Authors: Marreiros Bruno C. , Sena Filipa V. , Sousa Filipe M. , Oliveira A. Sofia F. , Soares Cláudio M. , Batista Ana P. , Pereira Manuela M.
Published: February 2017

Type II NADH:quinone oxidoreductases (NDH-2s) are membrane proteins involved in respiratory chains. These proteins contribute indirectly to the establishment of the transmembrane difference of electrochemical potential by catalyzing the reduction of quinone by oxidation of NAD(P)H. NDH-2s are widespread enzymes being present in the three domains of life. In this work, we explored the catalytic mechanism of NDH-2 by investigating the common elements of all NDH-2s, based on the rationale that conservation of such elements reflects their structural/functional importance. We observed conserved sequence motifs and structural elements among 1762 NDH-2s. We identified two proton pathways possibly involved in the protonation of the quinone. Our results led us to propose the first catalytic mechanism for NDH-2 family, in which a conserved glutamate residue, E172 (in NDH-2 from Staphylococcus aureus) plays a key role in proton transfer to the quinone pocket. This catalytic mechanism may also be extended to the other members of the two-Dinucleotide Binding Domains Flavoprotein (tDBDF) superfamily, such as sulfide:quinone oxidoreductases.
32 × 32 silicon electro-optic switch with built-in monitors and balanced-status units
Authors: Qiao Lei , Tang Weijie , Chu Tao
Published: February 2017

To construct large-scale silicon electro-optical switches for optical interconnections, we developed a method using a limited number of power monitors inserted at certain positions to detect and determine the optimum operating points of all switch units to eliminate non-uniform effects arising from fabrication errors. We also introduced an optical phase bias to one phase-shifter arm of a Mach–Zehnder interferometer (MZI)-type switch unit to balance the two operation statuses of a silicon electro-optical switch during push–pull operation. With these methods, a 32 × 32 MZI-based silicon electro-optical switch was successfully fabricated with 180-nm complementary metal–oxide–semiconductor (CMOS) process technology, which is the largest scale silicon electro-optical switch to the best of our knowledge. At a wavelength of 1520 nm, the on-chip insertion losses were 12.9 to 16.5 dB, and the crosstalk ranged from −17.9 to −24.8 dB when all units were set to the ‘Cross’ status. The losses were 14.4 to 18.5 dB, and the crosstalk ranged from −15.1 to −19.0 dB when all units were in the ‘Bar’ status. The total power consumptions of the 32 × 32 switch were 247.4 and 542.3 mW when all units were set to the ‘Cross’ and ‘Bar’ statuses, respectively.
Correction: Corrigendum: Long intergenic non-coding RNA 271 is predictive of a poorer prognosis of papillary thyroid cancer
Authors: Ma Ben , Liao Tian , Wen Duo , Dong Chuanpeng , Zhou Li , Yang Shuwen , Wang Yu , Ji Qinghai
Published: February 2017

Scientific Reports 6: Article number: 36973; published online: 11 November 2016; updated: 09 February 2017 This Article contains errors in Table 1 and Table 4. The correct Table 1 and Table 4 appear below as Table 1 and Table 2 respectively.
Responses of the marine diatom Thalassiosira pseudonana to changes in CO2 concentration: a proteomic approach
Authors: Clement Romain , Lignon Sabrina , Mansuelle Pascal , Jensen Erik , Pophillat Matthieu , Lebrun Regine , Denis Yann , Puppo Carine , Maberly Stephen C. , Gontero Brigitte
Published: February 2017

The concentration of CO2 in many aquatic systems is variable, often lower than the KM of the primary carboxylating enzyme Rubisco, and in order to photosynthesize efficiently, many algae operate a facultative CO2 concentrating mechanism (CCM). Here we measured the responses of a marine diatom, Thalassiosira pseudonana, to high and low concentrations of CO2 at the level of transcripts, proteins and enzyme activity. Low CO2 caused many metabolic pathways to be remodeled. Carbon acquisition enzymes, primarily carbonic anhydrase, stress, degradation and signaling proteins were more abundant while proteins associated with nitrogen metabolism, energy production and chaperones were less abundant. A protein with similarities to the Ca2+/ calmodulin dependent protein kinase II_association domain, having a chloroplast targeting sequence, was only present at low CO2. This protein might be a specific response to CO2 limitation since a previous study showed that other stresses caused its reduction. The protein sequence was found in other marine diatoms and may play an important role in their response to low CO2 concentration.
MicroRNA-100 is involved in shrimp immune response to white spot syndrome virus (WSSV) and Vibrio alginolyticus infection
Authors: Wang Zhi , Zhu Fei
Published: February 2017

In this study, we discovered that shrimp miR-100 was up-regulated at 24 h after WSSV or Vibrio alginolyticus infection, confirming its participation in the innate immune system of shrimp. The anti-miRNA oligonucleotide (AMO-miR-100) was applied to inhibit the expression of miR-100. After AMO-miR-100 treatment, the shrimp was challenged with WSSV or V. alginolyticus. The knockdown of miR-100 expression decreased the mortality of WSSV-infected shrimp from 24 h to 72 h post-infection and enhanced the mortality of V. alginolyticus-infected shrimp significantly. The knockdown of miR-100 affected phenoloxidase (PO) activity, superoxide dismutase (SOD) activity and total hemocyte count (THC) after the infection with WSSV or V. alginolyticus, indicating a regulative role of miR-100 in the immune potential of shrimp in the response to WSSV or V. alginolyticus infection. The knockdown of miR-100 induced the apoptosis of shrimp hemocytes, and V. alginolyticus + AMO-miR-100 treatment caused more hemocyte apoptosis than V. alginolyticus treatment. The miR-100 influenced also the morphology of shrimp hemocytes and regulated the phagocytosis of WSSV or V. alginolyticus. Thus, we concluded that miR-100 may promote the anti-Vibrio immune response of shrimp through regulating apoptosis, phagocytosis and PO activity and affects the progression of WSSV infection at a certain level.
Mediterranean versus Red sea corals facing climate change, a transcriptome analysis
Authors: Maor-Landaw Keren , Waldman Ben-Asher Hiba , Karako-Lampert Sarit , Salmon-Divon Mali , Prada Fiorella , Caroselli Erik , Goffredo Stefano , Falini Giuseppe , Dubinsky Zvy , Levy Oren
Published: February 2017

The anthropogenic increase in atmospheric CO2 that drives global warming and ocean acidification raises serious concerns regarding the future of corals, the main carbonate biomineralizers. Here we used transcriptome analysis to study the effect of long-term gradual temperature increase (annual rate), combined with lowered pH values, on a sub-tropical Red Sea coral, Stylophora pistillata, and on a temperate Mediterranean symbiotic coral Balanophyllia europaea. The gene expression profiles revealed a strong effect of both temperature increase and pH decrease implying for synergism response. The temperate coral, exposed to a twice as high range of seasonal temperature fluctuations than the Red Sea species, faced stress more effectively. The compensatory strategy for coping apparently involves deviating cellular resources into a massive up-regulation of genes in general, and specifically of genes involved in the generation of metabolic energy. Our results imply that sub-lethal, prolonged exposure to stress can stimulate evolutionary increase in stress resilience.
High chloride content calcium silicate glasses
Authors: Chen Xiaojing , Karpukhina Natalia , Brauer Delia S. , Hill Robert G.
Published: February 2017

Chloride is known to volatilize from silicate glass melts and until now, only limited studies on oxychloride silicate glasses have been reported. In this paper we have synthesized silicate glasses that retain large amount of CaCl2.
Frontiers in poly(ionic liquid)s: syntheses and applications
Authors: Qian Wenjing , Texter John , Yan Feng
Published: February 2017

Recent works on the syntheses and applications of poly(ionic liquid)s are reviewed.
Dihydrogen intermolecular contacts in group 13 compounds: H⋯H or E⋯H (E = B, Al, Ga) interactions?
Authors: Echeverría Jorge , Aullón Gabriel , Alvarez Santiago
Published: February 2017

A theoretical analysis rationalises the energetics and topology of B–H⋯H–B and B–H⋯B short contacts present in the crystal structures of many borane derivatives.
Benzoquinone-bridged Co2 complexes with different magnetic anisotropy induced by solvent molecules
Authors: Cao Wenhai , Zhu Xiaoquan , Liu Pengfei , Su Shaodong , Hu Shengmin , Wen Yuehong , Wu Xintao , Sheng Tianlu
Published: February 2017

The new benzoquinone-bridged Co2 complexes with different magnetic anisotropy induced by acetonitrile and water molecules are reported.
The anti-photoaging effect of antioxidant collagen peptides from silver carp (Hypophthalmichthys molitrix) skin is preferable to tea polyphenols and casein peptides
Authors: Zhang Ling , Zheng Yayao , Cheng Xiaofeng , Meng Mengfei , Luo Yongkang , Li Bo
Published: February 2017

The anti-photoaging effect of ACPs is preferable to TP and CP, and HCP is better than LCP and MCP.
Antithrombotic effect and mechanism of Rubus spp. Blackberry
Authors: Xie Pingyao , Zhang Yong , Wang Xuebiao , Wei Jinfeng , Kang Wenyi
Published: February 2017

The compounds ofRubusspp. Blackberry (RSB) were isolated and identified by a bioassay-guided method, and their antithrombotic effects and mechanism were investigated with the acute blood stasis rat model.
High-throughput screening of microchip-synthesized genes in programmable double-emulsion droplets
Authors: Chan H. F. , Ma S. , Tian J. , Leong K. W.
Published: February 2017

A high-throughput, miniaturized screening platform for microchip-synthesized genes using microfluidics-generated water-in-oil-in-water (W/O/W) double emulsion (DE) droplets is reported.
Regioselective Zn(OAc)2-catalyzed azide–alkyne cycloaddition in water: the green click-chemistry
Authors: Morozova Maria A. , Yusubov Mekhman S. , Kratochvil Bohumil , Eigner Václav , Bondarev Alexander A. , Yoshimura Akira , Saito Akio , Zhdankin Viktor V. , Trusova Marina E. , Postnikov Pavel S.
Published: February 2017

A new method of azide–alkyne cycloaddition (AAC) in the presence of Zn(OAc)2 as an inexpensive and environmentally friendly catalyst in neat water has been developed.
Iodine(iii)-induced regioselective carbocyclization of terminal alkynes: a facile approach to prepare 1,1-diiodomethylene substituted cyclic compounds
Authors: Wang Zeyu , Zhong Jiang , Zheng Chen , Fan Renhua
Published: February 2017

An iodine(iii)-induced regioselective carbocyclization of functionally substituted terminal alkynes to afford 1,1-diiodomethylene substituted cyclic compounds is reported.
The development and mechanistic investigation of a palladium-catalyzed 1,3-arylfluorination of chromenes
Authors: Thornbury Richard T. , Saini Vaneet , Fernandes Talita de A. , Santiago Celine B. , Talbot Eric P. A. , Sigman Matthew S. , McKenna Jeffrey M. , Toste F. Dean
Published: February 2017

A mild palladium-catalyzed ligand-controlled regioselective 1,3-arylfluorination of 2[H]-chromenes has been developed.
Challenges in calculating the bandgap of triazine-based carbon nitride structures
Authors: Steinmann Stephan N. , Melissen Sigismund T. A. G. , Le Bahers Tangui , Sautet Philippe
Published: February 2017

Graphitic carbon nitrides form a popular family of materials, particularly as photoharvesters in photocatalytic water splitting cells.
Asymmetric hydroarylation of vinyl ethers catalyzed by a hydroxoiridium complex: azoles as effective directing groups
Authors: Yamauchi Daisuke , Nishimura Takahiro , Yorimitsu Hideki
Published: February 2017

Asymmetric hydroarylation of vinyl ethers using azoles as directing groups was realized by use of a hydroxoiridium/chiral phosphine catalyst.
Quantifying and understanding the steric properties of N-heterocyclic carbenes
Authors: Gómez-Suárez Adrián , Nelson David J. , Nolan Steven P.
Published: February 2017

This Feature Article presents and discusses the use of different methods to quantify and explore the steric impact of N-heterocyclic carbene (NHC) ligands.
Precise elucidations of stacking manners of hydrogen-bonded two-dimensional organic frameworks composed of X-shaped π-conjugated systems
Authors: Hisaki Ichiro , Emilya Affendy N. Q. , Tohnai Norimitsu
Published: February 2017

Stacking manners of 2D-nCOFs with a porous rhombic network framework was precisely characterized based on single crystal X-ray diffraction analysis.
Analysis of charging-induced structural damage in electrochemical systems
Authors: Yang Fuqian
Published: February 2017

Structural damage caused by charging-induced change in the surface energy of an electrode film under the condition of weak bonding between the adsorbate and the substrate.
Lysozyme encapsulated gold nanoclusters: effects of cluster synthesis on natural protein characteristics
Authors: Russell B. A. , Jachimska B. , Komorek P. , Mulheran P. A. , Chen Y.
Published: February 2017

Protein encapsulated gold nanocluster synthesis within lysozyme proteins results in major changes to the native lysozyme's physicochemical characteristics.
Construction of leaf-like CuO–Cu2O nanocomposites on copper foam for high-performance supercapacitors
Authors: He Dong , Wang Guanda , Liu Guolong , Suo Hui , Zhao Chun
Published: February 2017

Leaf-like CuO–Cu2O nanosheets have been prepared on copper foam by a one-step simple anodization method, which can be used as an advanced binder-free supercapacitor electrode.
Design, synthesis and evaluation of new ligustrazine derivatives as potential plasma-stable neuroprotective agents
Authors: Zhang Chenze , Yan Wenqiang , Zhao Rui , Xu Bing , Fang Xiong , Yan Mengmeng , Zhang Yuzhong , Wang Penglong , Lei Haimin
Published: February 2017

To investigate plasma-stable neuroprotective agents, a series of new ligustrazine derivatives were synthesized by conjoining ligustrazine and phenols with ester, ether and amide bonds.
Biomimetic polymeric superhydrophobic surfaces and nanostructures: from fabrication to applications
Authors: Wen Gang , Guo ZhiGuang , Liu Weimin
Published: February 2017

This review provides a brief introduction of biomimetic polymeric superhydrophobic surfaces and comprehensive discussions about fabrication approaches and multifunctional applications, which are expected to advance the development of biomimetic polymeric superhydrophobic surfaces.
Correction: Detection and characterization of ponatinib reactive metabolites by liquid chromatography tandem mass spectrometry and elucidation of bioactivation pathways
Authors: Kadi Adnan A. , Darwish Hany W. , Attwa Mohamed W. , Amer Sawsan M.
Published: February 2017

Correction for ‘Detection and characterization of ponatinib reactive metabolites by liquid chromatography tandem mass spectrometry and elucidation of bioactivation pathways’ by Adnan A. Kadi et al., RSC Adv., 2016, 6, 72575–72585.
MicroRNA-143 suppresses oral squamous cell carcinoma cell growth, invasion and glucose metabolism through targeting hexokinase 2
Authors: Sun Xianghui , Zhang Lei
Published: February 2017

miRNAs are non-coding RNAs that have functions to regulate gene expression and play essential roles in a variety of biological processes of cancers. In the present study, we report miR-143 acts as a tumor suppressor in human oral squamous cell carcinoma (OSCC). The expressions of miR-143 are down-regulated in both OSCC cell lines and patient samples compared with normal adjacent tissues. We found overexpression of miR-143 in oral cancer cell lines suppresses cell migration, cellular glucose metabolism and proliferation. Moreover, overexpression of miR-143 promoted apoptosis and significantly caused cell cycle arrest at G1 stage. The colony formation of oral cancer cells was also suppressed by miR-143. We identified hexokinase 2 (HK2) as a direct target of miR-143 in oral cancer cells. Our data show that miR-143 complementary pairs to the 3′-UTR of HK2 in oral cancer cells, leading to the inhibition of glycolysis in vitro and in vivo. Moreover, knockdown of HK2 by siRNA in oral cancer cells inhibited glucose metabolism, proliferation and migration. Recovery of glucose metabolism by overexpression of HK2 in miR-143 overexpressing cells restores the cell migration and proliferation, suggesting that the miR-143-mediated cancer suppression is through the direct inhibition of HK2. In summary, the present studies highlight miR-143 as a tumor suppressor in OSCC by the suppression of cell migration, glucose metabolism and proliferation through directly targeting HK2, rendering miR-143 a therapeutic strategy for the treatment of clinical OSCC patients.
Neutral‐point voltage balancing in wind power NPC three‐level converter
Authors: Qian Peng , Li Liangbi
Published: February 2017

Neutral‐point‐clamped (NPC) three‐level converter has been widely used in wind power generation systems. However, traditional NPC three‐level converter often suffers excessive voltage fluctuation at the neutral point of DC‐link capacitors. This problem may leads to switching devices damage and increases additional harmonics in output voltage of the converter. To solve this problem, a compensating scheme based on a current compensation method is proposed. The results show that the proposed scheme can alleviate considerably voltage fluctuation. Consequently, it is effective and can also enhance the reliability of the converter.
Decentralised adaptive robust control schemes of uncertain large‐scale time‐delay systems with multiple unknown dead‐zone inputs
Authors: Wu Hansheng
Published: February 2017

A simple design method is presented such that the decentralised adaptive robust control schemes with a relatively simple structure can be synthesised for a class of uncertain large‐scale interconnected time‐delay systems with multiple dead‐zone inputs. It is supposed that any information on dead‐zone input non‐linearities is completely unknown. On the basis of adaptive technique, a self‐tuning control gain function is introduced for each subsystem to construct a simple local state feedback controller which is structurally linear in the local state variables. The simple design method presented in this study might be well understood by engineering designers, and the resulting simple control schemes can be easily implemented in a number of practical engineering control problems. By combining the presented design method with other control methods, one may expect to obtain a number of interesting results for a rather large class of uncertain interconnected dynamical systems with completely unknown dead‐zone in the actuators. Finally, the simulations of some numerical examples are provided to show the design procedure of the presented method and to demonstrate the validity of the theoretical results.
Mode‐dependent robust stability and stabilisation of uncertain networked control systems via an average dwell time switching approach
Authors: Wu Ying , Wu Yanpeng
Published: February 2017

The stability analysis and synthesis problem of networked control systems (NCSs) with communication limits and system uncertainties is investigated via an average dwell time switching control method. Active time‐varying sampling strategy and hybrid node driven mode are proposed to generate a series of one‐step time delay subsystems of closed‐loop NCS. Gridding approach is introduced to transform the continuous time axis into discrete time sequences which limits the switching rules in a finite set. By constructing multiple parameter‐dependent quadratic Lyapunov‐like functions with norm bounded uncertainties, sufficient stability conditions are derived and the robust mode‐dependent network controller is designed to guarantee the proposed uncertain switched NCS globally asymptotically stable for any switching signal with admissible ADT. A for‐loop algorithm is integrated into the formulated LMI optimisation problem to avoid predefining the switching sequence and the occurring times of network induced factors. Finally, simulation results illustrate the effectiveness of the proposed methods.
MIMO antennas using controlled orthogonal characteristic modes by metal rims
Authors: Qu Longyue , Lee Hongkoo , Shin Hyunwoong , Kim Min‐Gi , Kim Hyeongdong
Published: February 2017

A metal‐rimmed multiple‐input multiple‐output (MIMO) antenna design operating below the 1 GHz frequency band is proposed that offers a wide bandwidth, high isolation, low correlation, and compact size. The proposed technique is based on metal‐rimmed mobile phones with four gaps, and the overall design occupies a small size in the ground plane. Orthogonal ground mode resonances are controlled to be equal to the operating frequencies, providing high antenna performance and good diversity performance. The proposed main antenna is achieved by utilizing the upper‐side rim to tune the ground mode resonance along the length of the ground plane to be equal to the operating frequency; moreover, a coupling slot couples strongly with the ground mode resonance to achieve a ‐6 dB bandwidth from 0.695 to 1 GHz (305 MHz). The orthogonal ground mode along the width of the ground plane is used for diversity antenna design. Similarly, the ground mode resonance is made equal to the operating frequency by controlling the left‐side metal rim such that a simulated ‐6 dB bandwidth from 0.850 to 0.920 GHz (70 MHz) is achieved. The simulated isolation is more than 11.5 dB in the operating band, and the measured envelope correlation coefficients is below 0.1.
Ultra‐compact dual‐polarised UWB MIMO antenna with meandered feeding lines
Authors: Khan Muhammad Saeed , Capobianco Antonio‐Daniele , Iftikhar Adnan , Shubair Raed M. , Anagnostou Dimitris E. , Braaten Benjamin D.
Published: February 2017

An ultra‐compact dual‐polarised ultra‐wideband multi‐input multi‐output antenna made with a single‐shared‐radiating element and two meandered feeding lines are proposed. Miniaturisation is achieved by using a combination of techniques, including a resonant stub connected to the ground through which shorts the excessive coupled energy before it reaches the other port and minimises coupling, slots etched in the radiator that also help minimise mutual coupling, while the meandered lines allow to bring the antenna closer to the greatly reduce the overall size of the antenna. Slots etched in the radiator and the use of a stub connected to the ground through, help to minimise the mutual coupling. The formation of orthogonal surface currents provides the necessary dual polarisation. Simulated and measured results demonstrate the wideband impedance matching, low mutual coupling and low envelope correlation coefficient. This antenna has an extremely compact size (22 × 24.3 mm2, including the ground plane) that makes it an excellent candidate for portable and handheld devices.
Characterizing solar-type stars from full-length Kepler data sets using the Asteroseismic Modeling Portal
Authors: Creevey O. L. , Metcalfe T. S. , Schultheis M. , Salabert D. , Bazot M. , Thévenin F. , Mathur S. , Xu H. , García R. A.
Published: February 2017

The Kepler space telescope yielded unprecedented data for the study of solar-like oscillations in other stars. The large samples of multi-year observations posed an enormous data analysis challenge that has only recently been surmounted. Asteroseismic modeling has become more sophisticated over time, with better methods gradually developing alongside the extended observations and improved data analysis techniques. We apply the latest version of the Asteroseismic Modeling Portal (AMP) to the full-length Kepler data sets for 57 stars, comprising planetary hosts, binaries, solar-analogs, active stars, and for validation purposes, the Sun. From an analysis of the derived stellar properties for the full sample, we identify a variation of the mixing-length parameter with atmospheric properties. We also derive a linear relation between the stellar age and a characteristic frequency separation ratio. In addition, we find that the empirical correction for surface effects suggested by Kjeldsen and coworkers is adequate for solar-type stars that are not much hotter (Teff≲6200 K) or significantly more evolved (log g≳4.2, ⟨ Δν ⟩≳80 μHz) than the Sun. Precise parallaxes from the Gaia mission and future observations from TESS and PLATO promise to improve the reliability of stellar properties derived from asteroseismology.
Hauptstadtkongress 2017: Für jeden etwas dabei
Authors: Hillebrand Ralf-Thomas
Published: February 2017

Auf dem Hauptstadtkongress in Berlin wirft der Bundestagswahlkampf seinen Schatten voraus. Vom 20. bis 22. Juni erwarten die Veranstalter wieder mehr als 8.000 Fachbesucher aus Politik, Verbänden und der Gesundheitswirtschaft.
Comparing van der Waals DFT methods for water on NaCl(001) and MgO(001)
Authors: Kebede Getachew G. , Spångberg Daniel , Mitev Pavlin D. , Broqvist Peter , Hermansson Kersti
Published: February 2017

In this work, a range of van der Waals type density functionals are applied to the H2O/NaCl(001) and H2O/MgO(001) interface systems to explore the effect of an explicit dispersion treatment. The functionals we use are the self-consistent vdW functionals vdW-DF, vdW-DF2, optPBE-vdW, optB88-vdW, optB86b-vdW, and vdW-DF-cx, as well as the dispersion-corrected PBE-TS and PBE-D2 methods; they are all compared with the standard PBE functional. For both NaCl(001) and MgO(001), we find that the dispersion-flavoured functionals stabilize the water-surface interface by approximately 20%-40% compared to the PBE results. For NaCl(001), where the water molecules remain intact for all overlayers, the dominant contribution to the adsorption energy from “density functional theory dispersion” stems from the water-surface interactions rather than the water-water interactions. The optPBE-vdW and vdW-DF-cx functionals yield adsorption energies in good agreement with available experimental values for both NaCl and MgO. To probe the strengths of the perturbations of the adsorbed water molecules, we also calculated water dipole moments and found an increase up to 85% for water at the MgO(001) surface and 70% at the NaCl(001) surface, compared to the gas-phase dipole moment.
Plasma potential of a moving ionization zone in DC magnetron sputtering
Authors: Panjan Matjaž , Anders André
Published: February 2017

Using movable emissive and floating probes, we determined the plasma and floating potentials of an ionization zone (spoke) in a direct current magnetron sputtering discharge. Measurements were recorded in a space and time resolved manner, which allowed us to make a three-dimensional representation of the plasma potential. From this information we could derive the related electric field, space charge, and the related spatial distribution of electron heating. The data reveal the existence of strong electric fields parallel and perpendicular to the target surface. The largest E-fields result from a double layer structure at the leading edge of the ionization zone. We suggest that the double layer plays a crucial role in the energization of electrons since electrons can gain several 10 eV of energy when crossing the double layer. We find sustained coupling between the potential structure, electron heating, and excitation and ionization processes as electrons drift over the magnetron target. The brightest region of an ionization zone is present right after the potential jump, where drifting electrons arrive and where most local electron heating occurs. The ionization zone intensity decays as electrons continue to drift in the Ez × B direction, losing energy by inelastic collisions; electrons become energized again as they cross the potential jump. This results in the elongated, arrowhead-like shape of the ionization zone. The ionization zone moves in the –Ez × B direction from which the to-be-heated electrons arrive and into which the heating region expands; the zone motion is dictated by the force of the local electric field on the ions at the leading edge of the ionization zone. We hypothesize that electron heating caused by the potential jump and physical processes associated with the double layer also apply to magnetrons at higher discharge power, including high power impulse magnetron sputtering.
Role of defects and their complexes on the dependence of photoconductivity on dark resistivity of single ZnO microwires
Authors: Villafuerte M. , Zamora D. J. , Bridoux G. , Ferreyra J. M. , Meyer M. , Heluani S. P.
Published: February 2017

We have studied the correlation between the photoconductivity and the dark resistivity of single ZnO microwires. We found that as-grown microwires with higher dark resistivities have higher photoconductivities. However, when the microwires are thermal treated in vacuum, this correlation is inverted. We have also analyzed the behavior of photoconductivity on protonated as-grown samples. We discuss the origin of these behaviors in terms of the interplay of oxygen and zinc vacancies and their complexes acting as recombination or trapping centers.
Incommensurate quantum-size oscillations in acene-based molecular wires—Effects of quantum fluctuations
Authors: Schmitteckert Peter , Thomale Ronny , Korytár Richard , Evers Ferdinand
Published: February 2017

Molecular wires of the acene-family can be viewed as a physical realization of a two-rung ladder Hamiltonian. For acene-ladders, closed-shell ab initio calculations and elementary zone-folding arguments predict incommensurate gap oscillations as a function of the number of repetitive ring units, NR, exhibiting a period of about ten rings. Results employing open-shell calculations and a mean-field treatment of interactions suggest anti-ferromagnetic correlations that could potentially open a large gap and wash out the gap oscillations. Within the framework of a Hubbard model with repulsive on-site interaction, U, we employ a Hartree-Fock analysis and the density matrix renormalization group to investigate the interplay of gap oscillations and interactions. We confirm the persistence of incommensurate oscillations in acene-type ladder systems for a significant fraction of parameter space spanned by U and NR.
Practical approximation of the non-adiabatic coupling terms for same-symmetry interstate crossings by using adiabatic potential energies only
Authors: Baeck Kyoung Koo , An Heesun
Published: February 2017

A very simple equation, FijApp=[(∂2(Via−Vja)/∂Q2)/(Via−Vja)]1/2/2, giving a reliable magnitude of non-adiabatic coupling terms (NACTs, Fij’s) based on adiabatic potential energies only (Via and Vja) was discovered, and its reliability was tested for several prototypes of same-symmetry interstate crossings in LiF, C2, NH3Cl, and C6H5SH molecules. Our theoretical derivation starts from the analysis of the relationship between the Lorentzian dependence of NACTs along a diabatization coordinate and the well-established linear vibronic coupling scheme. This analysis results in a very simple equation, α=2κ/Δc, enabling the evaluation of the Lorentz function α parameter in terms of the coupling constant κ and the energy gap Δc (Δc=|Via−Vja|Qc) between adiabatic states at the crossing point QC. Subsequently, it was shown that QC corresponds to the point where FijApp exhibit maximum values if we set the coupling parameter as κ=[(Via−Vja)⋅(∂2(Via−Vja)/∂Q2)]Qc1/2/2. Finally, we conjectured that this relation could give reasonable values of NACTs not only at the crossing point but also at other geometries near QC. In this final approximation, the pre-defined crossing point QC is not required. The results of our test demonstrate that the approximation works much better than initially expected. The present new method does not depend on the selection of an ab initio method for adiabatic electronic states but is currently limited to local non-adiabatic regions where only two electronic states are dominantly involved within a nuclear degree of freedom.
Generalized spin-ratio scaled MP2 method for accurate prediction of intermolecular interactions for neutral and ionic species
Authors: Tan Samuel , Barrera Acevedo Santiago , Izgorodina Ekaterina I.
Published: February 2017

The accurate calculation of intermolecular interactions is important to our understanding of properties in large molecular systems. The high computational cost of the current “gold standard” method, coupled cluster with singles and doubles and perturbative triples (CCSD(T), limits its application to small- to medium-sized systems. Second-order Møller–Plesset perturbation (MP2) theory is a cheaper alternative for larger systems, although at the expense of its decreased accuracy, especially when treating van der Waals complexes. In this study, a new modification of the spin-component scaled MP2 method was proposed for a wide range of intermolecular complexes including two well-known datasets, S22 and S66, and a large dataset of ionic liquids consisting of 174 single ion pairs, IL174. It was found that the spin ratio, ϵΔs=EINTOSEINTSS, calculated as the ratio of the opposite-spin component to the same-spin component of the interaction correlation energy fell in the range of 0.1 and 1.6, in contrast to the range of 3–4 usually observed for the ratio of absolute correlation energy, ϵs=EOSESS, in individual molecules. Scaled coefficients were found to become negative when the spin ratio fell in close proximity to 1.0, and therefore, the studied intermolecular complexes were divided into two groups: (1) complexes with ϵΔs< 1 and (2) complexes with ϵΔs≥ 1. A separate set of coefficients was obtained for both groups. Exclusion of counterpoise correction during scaling was found to produce superior results due to decreased error. Among a series of Dunning’s basis sets, cc-pVTZ and cc-pVQZ were found to be the best performing ones, with a mean absolute error of 1.4 kJ mol−1 and maximum errors below 6.2 kJ mol−1. The new modification, spin-ratio scaled second-order Møller–Plesset perturbation, treats both dispersion-driven and hydrogen-bonded complexes equally well, thus validating its robustness with respect to the interaction type ranging from ionic to neutral species at minimal computational cost.
Particle size dependence of the magnetic and magneto-caloric properties of HoCrO3
Authors: Yin Shiqi , Sauyet Theodore , Seehra Mohindar S. , Jain Menka
Published: February 2017

Magnetic and magneto-caloric properties of polycrystalline powder samples of HoCrO3 with four different particle sizes are reported here. The samples were prepared by citrate method and were annealed at 700, 900, 1100, and 1300 °C to yield average particle sizes of 60 nm, 190 nm, 320 nm, and 425 nm, respectively, as determined by the analysis of X-ray diffraction patterns and images obtained by scanning electron microscopy. Additional structural characterization was done using Raman spectroscopy. Measurements of the magnetization of the samples were done from 5 K to 300 K in magnetic fields up to 70 kOe. Analysis of the temperature dependence of the paramagnetic susceptibility in terms of the modified Curie-Weiss law, including the Dzyaloshinsky-Moriya (DM) interaction, show small but systematic changes in the Néel temperature TNCr of Cr3+ ions, exchange constant J, and the DM interaction with variation in particle size. However, below TNCr  the largest size-dependent effects are observed at 5 K, and the measured magnitudes of coercivity field HC are 1930, 2500, 4660, and 7790 Oe for the 60 nm, 190 nm, 320 nm, and 425 nm size particles, respectively, which can be interpreted by a single domain model. Enhancement of the particle size gives about a fourfold increase in the magnitude of the energy product, HC * MS, where MS is the saturation magnetization. However, as the particle size rises, an opposite trend is observed in the max magnetic entropy (ΔSM = 8.73, 7.22, 7.77, and 6.70 J/kg K) and the refrigerant capacity (RC = 388, 354, 330, and 310 J/kg) for the 60 nm, 190 nm, 320 nm, and 425 nm size particles, respectively. These results suggest ways to optimize the properties of HoCrO3 for applications in magnetic storage and magnetic refrigeration.
Lead free Ba0.8Ca0.2TexTi1−xO3 ferroelectric ceramics exhibiting high electrocaloric properties
Authors: Asbani B. , Gagou Y. , Dellis J.-L. , Trček M. , Kutnjak Z. , Amjoud M. , Lahmar A. , Mezzane D. , El Marssi M.
Published: February 2017

Direct and indirect electrocaloric measurements were performed on the new Tellurium (Te) doped Ba0.8Ca0.2TiO3 (BCT) ceramics. The effects of Te addition on structural, electrical, and electrocaloric properties of BCT ceramics were investigated. The incorporation of the Te element in the BCT induced the decrease of the Curie temperature and the enhancement of the electrocaloric effect. The significant electrocaloric temperature change ΔT = 1.237 K determined by the direct method was obtained at the relatively moderate field of ∼25 kV/cm in Ba0.8Ca0.2Ti(1−x)TexO3 with x = 0.02. The corresponding electrocaloric responsivity ΔT/ΔE = 0.495 × 10−6 K m V−1 is higher than that observed in pure BCT ceramics and is one of the highest reported so far in lead-free ferroelectric materials. The material's coefficient of performance was determined at the phase transition with a maximal value of 14.7.
Au-free ohmic Ti/Al/TiN contacts to UID n-GaN fabricated by sputter deposition
Authors: Garbe V. , Weise J. , Motylenko M. , Münchgesang W. , Schmid A. , Rafaja D. , Abendroth B. , Meyer D. C.
Published: February 2017

The fabrication and characterization of an Au-free Ti/Al/TiN (20/100/100 nm) contact stack to unintentionally doped n-GaN with TiN serving as the diffusion barrier is presented. Sputter deposition and lift-off in combination with post deposition annealing at 850 °C are used for contact formation. After annealing, contact shows ohmic behavior to n-GaN and a specific contact resistivity of 1.60 × 10−3 Ω cm2. To understand the contact formation on the microscopic scale, the contact was characterized by current–voltage measurements, linear transmission line method, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results show the formation of Ti-N bonds at the GaN/Ti interface in the as-deposited stack. Annealing leads to diffusion of Ti, Al, Ga, and N, and the remaining metallic Ti is fully consumed by the formation of the intermetallic tetragonal Al3Ti phase. Native oxide from the GaN surface is trapped during annealing and accumulated in the Al interlayer. The TiN capping layer, however, was chemically stable during annealing. It prevented oxidation of the Ti/Al contact bilayer successfully and thus proved to be a well suitable diffusion barrier with ideal compatibility to the Ti/Al contact metallization.
Generation of 20 kA electron beam from a laser wakefield accelerator
Authors: Li Y. F. , Li D. Z. , Huang K. , Tao M. Z. , Li M. H. , Zhao J. R. , Ma Y. , Guo X. , Wang J. G. , Chen M. , Hafz N. , Zhang J. , Chen L. M.
Published: February 2017

We present the experimentally generated electron bunch from laser-wakefield acceleration (LWFA) with a charge of 620 pC and a maximum energy up to 0.6 GeV by irradiating 80 TW laser pulses at a 3 mm Helium gas jet. The charge of injected electrons is much larger than the normal scaling laws of LWFA in bubble regime. We also got a quasi-monoenergetic electron beam with energy peaked at 249 MeV and a charge of 68 pC with the similar laser conditions but lower plasma density. As confirmed by 2D particle-in-cell simulations, the boosted bunch charge is due to the continuous injection caused by the self-steepening and self-compression of a laser pulse. During the nonlinear evolution of the laser pulse, the bubble structure broadens and stretches, leading to a longer dephasing length and larger beam charge.
Advantage of spatial map ion imaging in the study of large molecule photodissociation
Authors: Lee Chin , Lin Yen-Cheng , Lee Shih-Huang , Lee Yin-Yu , Tseng Chien-Ming , Lee Yuan-Tseh , Ni Chi-Kung
Published: February 2017

The original ion imaging technique has low velocity resolution, and currently, photodissociation is mostly investigated using velocity map ion imaging. However, separating signals from the background (resulting from undissociated excited parent molecules) is difficult when velocity map ion imaging is used for the photodissociation of large molecules (number of atoms ≥ 10). In this study, we used the photodissociation of phenol at the S1 band origin as an example to demonstrate how our multimass ion imaging technique, based on modified spatial map ion imaging, can overcome this difficulty. The photofragment translational energy distribution obtained when multimass ion imaging was used differed considerably from that obtained when velocity map ion imaging and Rydberg atom tagging were used. We used conventional translational spectroscopy as a second method to further confirm the experimental results, and we conclude that data should be interpreted carefully when velocity map ion imaging or Rydberg atom tagging is used in the photodissociation of large molecules. Finally, we propose a modified velocity map ion imaging technique without the disadvantages of the current velocity map ion imaging technique.