bluuebunny/crossref_metadata_2025 huggingface dataset:
Putting logic-based distributed systems on stable grounds
Authors: AMELOOT TOM J. , VAN DEN BUSSCHE JAN , MARCZAK WILLIAM R. , ALVARO PETER , HELLERSTEIN JOSEPH M.
Published: August 2015

In the Declarative Networking paradigm, Datalog-like languages are used to express distributed computations. Whereas recently formal operational semantics for these languages have been developed, a corresponding declarative semantics has been lacking so far. The challenge is to capture precisely the amount of nondeterminism that is inherent to distributed computations due to concurrency, networking delays, and asynchronous communication. This paper shows how a declarative, model-based semantics can be obtained by simply using the well-known stable model semantics for Datalog with negation. We show that the model-based semantics matches previously proposed formal operational semantics.
The Importance of Dunes on a Variety of Planetary Surfaces
Authors: Titus Timothy , Zimbelman James , Radebaugh Jani
Published: August 2015

The Fourth International Planetary Dunes Workshop: Integrating Models, Remote Sensing, and Field Data; Boise, Idaho, 19–22 May 2015
Priorities for Antarctic Research: Glaciers, Genomes, and Cosmic Waves
Authors: Wendel JoAnna
Published: August 2015

The next decade of research should focus on the need to understand the changing Antarctic environment and how organisms adapt to it, a high-level report says.
A novel lncRNA, LUADT1, promotes lung adenocarcinoma proliferation via the epigenetic suppression of p27
Authors: Qiu M , Xu Y , Wang J , Zhang E , Sun M , Zheng Y , Li M , Xia W , Feng D , Yin R , Xu L
Published: August 2015

Long noncoding RNAs (lncRNAs) are known to regulate the development and progression of various cancers. However, few lncRNAs have been well characterized in lung adenocarcinoma (LUAD). Here, we identified the expression profile of lncRNAs and protein-coding genes via microarrays analysis of paired LUAD tissues and adjacent non-tumor tissues from five female non-smokes with LUAD. A total of 498 lncRNAs and 1691 protein-coding genes were differentially expressed between LUAD tissues and paired adjacent normal tissues. A novel lncRNA, LUAD transcript 1 (LUADT1), which is highly expressed in LUAD and correlates with T stage, was characterized. Both in vitro and in vivo data showed that LUADT1 knockdown significantly inhibited proliferation of LUAD cells and induced cell cycle arrest at the G0–G1 phase. Further analysis indicated that LUADT1 may regulate cell cycle progression by epigenetically inhibiting the expression of p27. RNA immunoprecipitation and chromatin immunoprecipitation assays confirmed that LUADT1 binds to SUZ12, a core component of polycomb repressive complex 2, and mediates the trimethylation of H3K27 at the promoter region of p27. The negative correlation between LUADT1 and p27 expression was confirmed in LUAD tissue samples. These data suggested that a set of lncRNAs and protein-coding genes were differentially expressed in LUAD. LUADT1 is an oncogenic lncRNA that regulates LUAD progression, suggesting that dysregulated lncRNAs may serve as key regulatory factors in LUAD progression.
Single-shot spectro-temporal characterization of XUV pulses from a seeded free-electron laser
Authors: De Ninno Giovanni , Gauthier David , Mahieu Benoît , Ribič Primož Rebernik , Allaria Enrico , Cinquegrana Paolo , Danailov Miltcho Bojanov , Demidovich Alexander , Ferrari Eugenio , Giannessi Luca , Penco Giuseppe , Sigalotti Paolo , Stupar Matija
Published: August 2015

Intense ultrashort X-ray pulses produced by modern free-electron lasers (FELs) allow one to probe biological systems, inorganic materials and molecular reaction dynamics with nanoscale spatial and femtoscale temporal resolution. These experiments require the knowledge, and possibly the control, of the spectro-temporal content of individual pulses. FELs relying on seeding have the potential to produce spatially and temporally fully coherent pulses. Here we propose and implement an interferometric method, which allows us to carry out the first complete single-shot spectro-temporal characterization of the pulses, generated by an FEL in the extreme ultraviolet spectral range. Moreover, we provide the first direct evidence of the temporal coherence of a seeded FEL working in the extreme ultraviolet spectral range and show the way to control the light generation process to produce Fourier-limited pulses. Experiments are carried out at the FERMI FEL in Trieste.
ZnuA and zinc homeostasis in Pseudomonas aeruginosa
Authors: Pederick Victoria G. , Eijkelkamp Bart A. , Begg Stephanie L. , Ween Miranda P. , McAllister Lauren J. , Paton James C. , McDevitt Christopher A.
Published: August 2015

Pseudomonas aeruginosa is a ubiquitous environmental bacterium and a clinically significant opportunistic human pathogen. Central to the ability of P. aeruginosa to colonise both environmental and host niches is the acquisition of zinc. Here we show that P. aeruginosa PAO1 acquires zinc via an ATP-binding cassette (ABC) permease in which ZnuA is the high affinity, zinc-specific binding protein. Zinc uptake in Gram-negative organisms predominantly occurs via an ABC permease and consistent with this expectation a P. aeruginosa ΔznuA mutant strain showed an ~60% reduction in cellular zinc accumulation, while other metal ions were essentially unaffected. Despite the major reduction in zinc accumulation, minimal phenotypic differences were observed between the wild-type and ΔznuA mutant strains. However, the effect of zinc limitation on the transcriptome of P. aeruginosa PAO1 revealed significant changes in gene expression that enable adaptation to low-zinc conditions. Genes significantly up-regulated included non-zinc-requiring paralogs of zinc-dependent proteins and a number of novel import pathways associated with zinc acquisition. Collectively, this study provides new insight into the acquisition of zinc by P. aeruginosa PAO1, revealing a hitherto unrecognized complexity in zinc homeostasis that enables the bacterium to survive under zinc limitation.
The Role of Scleraxis in Fate Determination of Mesenchymal Stem Cells for Tenocyte Differentiation
Authors: Li Yonghui , Ramcharan Melissa , Zhou Zuping , Leong Daniel J. , Akinbiyi Takintope , Majeska Robert J. , Sun Hui B.
Published: August 2015

Mesenchymal stem cells (MSCs) are pluripotent cells that primarily differentiate into osteocytes, chondrocytes and adipocytes. Recent studies indicate that MSCs can also be induced to generate tenocyte-like cells; moreover, MSCs have been suggested to have great therapeutic potential for tendon pathologies. Yet the precise molecular cascades governing tenogenic differentiation of MSCs remain unclear. We demonstrate scleraxis, a transcription factor critically involved in embryonic tendon development and formation, plays a pivotal role in the fate determination of MSC towards tenocyte differentiation. Using murine C3H10T1/2 pluripotent stem cells as a model system, we show scleraxis is extensively expressed in the early phase of bone morphogenetic protein (BMP)-12-triggered tenocytic differentiation. Once induced, scleraxis directly transactivates tendon lineage-related genes such as tenomodulin and suppresses osteogenic, chondrogenic and adipogenic capabilities, thus committing C3H10T1/2 cells to differentiate into the specific tenocyte-like lineage, while eliminating plasticity for other lineages. We also reveal that mechanical loading-mediated tenocytic differentiation follows a similar pathway and that BMP-12 and cyclic uniaxial strain act in an additive fashion to augment the maximal response by activating signal transducer Smad8. These results provide critical insights into the determination of multipotent stem cells to the tenocyte lineage induced by both chemical and physical signals.
Less is More: Design of a Highly Stable Disulfide-Deleted Mutant of Analgesic Cyclic α-Conotoxin Vc1.1
Authors: Yu Rilei , Seymour Victoria A. L. , Berecki Géza , Jia Xinying , Akcan Muharrem , Adams David J. , Kaas Quentin , Craik David J.
Published: August 2015

Cyclic α-conotoxin Vc1.1 (cVc1.1) is an orally active peptide with analgesic activity in rat models of neuropathic pain. It has two disulfide bonds, which can have three different connectivities, one of which is the native and active form. In this study we used computational modeling and nuclear magnetic resonance to design a disulfide-deleted mutant of cVc1.1, [C2H,C8F]cVc1.1, which has a larger hydrophobic core than cVc1.1 and, potentially, additional surface salt bridge interactions. The new variant, hcVc1.1, has similar structure and serum stability to cVc1.1 and is highly stable at a wide range of pH and temperatures. Remarkably, hcVc1.1 also has similar selectivity to cVc1.1, as it inhibited recombinant human α9α10 nicotinic acetylcholine receptor-mediated currents with an IC50 of 13 μM and rat N-type (Cav2.2) and recombinant human Cav2.3 calcium channels via GABAB receptor activation, with an IC50 of ~900 pM. Compared to cVc1.1, the potency of hcVc1.1 is reduced three-fold at both analgesic targets, whereas previous attempts to replace Vc1.1 disulfide bonds by non-reducible dicarba linkages resulted in at least 30-fold decreased activity. Because it has only one disulfide bond, hcVc1.1 is not subject to disulfide bond shuffling and does not form multiple isomers during peptide synthesis.
Self-assembling process of Oxalamide compounds and their nucleation efficiency in bio-degradable Poly(hydroxyalkanoate)s
Authors: Ma Piming , Deshmukh Yogesh S. , Wilsens Carolus H.R.M. , Ryan Hansen Michael , Graf Robert , Rastogi Sanjay
Published: August 2015

One of the key requirements in semi-crystalline polyesters, synthetic or bio-based, is the control on crystallization rate and crystallinity. One of the limiting factors in the commercialization of the bio-based polyesters, for example polyhydroxyalkanoates synthesized by bacteria for energy storage purposes, is the slow crystallization rate. In this study, we show that by tailoring the molecular structure of oxalamide compounds, it is possible to dissolve these compounds in molten poly(hydroxybutyrate) (PHB), having a hydroxyvalerate co-monomer content of less than 2 mol%. Upon cooling the polymer melt, the homogeneously dispersed oxalamide compound crystallizes just below the melting temperature of the polymer. The phase-separated compound reduces the nucleation barrier of the polymer, thus enhancing the crystallization rate, nucleation density and crystallinity. The findings reported in this study provide a generic route for the molecular design of oxalamide-based compounds that can be used for enhancing nucleation efficiency of semi-crystalline bio-based polyesters.
Association of p53 rs1042522, MDM2 rs2279744 and p21 rs1801270 polymorphisms with retinoblastoma risk and invasion in a Chinese population
Authors: Chen Rongxin , Liu Shu , Ye Huijing , Li Jiali , Du Yi , Chen Lingyan , Liu Xiaoman , Ding Yungang , Li Qian , Mao Yuxiang , Ai Siming , Zhang Ping , Ma Wenfang , Yang Huasheng
Published: August 2015

Single nucleotide polymorphisms (SNPs) of p53 rs1042522, MDM2 rs2279744 and p21 rs1801270, all in the p53 pathway, which plays a crucial role in DNA damage and genomic instability, were reported to be associated with cancer risk and pathologic characteristics. This case-control study was designed to analyse the association between these SNPs and retinoblastoma (RB) in a Chinese Han population. These SNPs in 168 RB patients and 185 adult controls were genotyped using genomic DNA from venous blood. No significant difference was observed in allele or genotypic frequencies of these SNPs between Chinese RB patients and controls (all P > 0.05). However, the rs1042522 GC genotype showed a protective effect against RB invasion, as demonstrated by event-free survival (HR = 0.53, P = 0.007 for GC versus GG/CC). This effect was significant for patients with a lag time >1 month and no pre-enucleation treatment (P = 0.007 and P = 0.010, respectively), indicating an interaction between p53 rs1042522 and clinical characteristics, including lag time and pre-enucleation treatment status. Thus, the rs1042522 SNP may be associated with RB invasion in the Han Chinese population; however, further large and functional studies are needed to assess the validity of this association.
All oxide semiconductor-based bidirectional vertical p-n-p selectors for 3D stackable crossbar-array electronics
Authors: Bae Yoon Cheol , Lee Ah Rahm , Baek Gwang Ho , Chung Je Bock , Kim Tae Yoon , Park Jea Gun , Hong Jin Pyo
Published: August 2015

Three-dimensional (3D) stackable memory devices including nano-scaled crossbar array are central for the realization of high-density non-volatile memory electronics. However, an essential sneak path issue affecting device performance in crossbar array remains a bottleneck and a grand challenge. Therefore, a suitable bidirectional selector as a two-way switch is required to facilitate a major breakthrough in the 3D crossbar array memory devices. Here, we show the excellent selectivity of all oxide p-/n-type semiconductor-based p-n-p open-based bipolar junction transistors as selectors in crossbar memory array. We report that bidirectional nonlinear characteristics of oxide p-n-p junctions can be highly enhanced by manipulating p-/n-type oxide semiconductor characteristics. We also propose an associated Zener tunneling mechanism that explains the unique features of our p-n-p selector. Our experimental findings are further extended to confirm the profound functionality of oxide p-n-p selectors integrated with several bipolar resistive switching memory elements working as storage nodes.
Preparation of fluorine functionalized magnetic nanoparticles for fast extraction and analysis of perfluorinated compounds from traditional Chinese medicine samples
Authors: Yan Zhihong , Zhu Genhua , Cai Ying , Yuan Jinbin , Yao Shouzhuo
Published: August 2015

Magnetic solid-phase extraction for the enrichment of PFCs from sample solution.
Selective recognition and sensing for adenosine triphosphate by label-free electrochemistry based on its inclusion with per-6-ammonium-β-cyclodextrin
Authors: Yang Ni , Wei Yongfeng , Kang Xiaofeng , Su Zhuoqun
Published: August 2015

A method for sensing adenosine triphosphate by its competitive inclusion to displace ferrocenecarboxylic acid from its inclusion complex with per-6-ammonium-β-cyclodextrin and the DPV curves.
Quantitative analysis of the water of crystallization of gypsum by near-infrared spectroscopy in Yungang Grottoes
Authors: Zhao Yang , Li Meiying , Wei Xia , Shen Xinyu , Gao Feng , Tong Hua
Published: August 2015

Near infrared spectroscopy is considered to be an effective analytical tool which is used in various fields, however, it is rarely used in the analysis of the water of crystallization of rocks from stone relics.
Simultaneous determination of ivabradine, metoprolol and their metabolites in rat plasma by ultra-performance liquid chromatography tandem mass spectrometry and its application in a pharmacokinetic study
Authors: Sun Wei , Chen Ruimin , Li Wanshu , Zhang Hui , Ye Jifeng , Cui Xiao , Huang Chengke
Published: August 2015

A sensitive and rapid UPLC-MS/MS method was developed to determine ivabradine, metoprolol and their corresponding metabolites in rat plasma simultaneously.
A preliminary investigation to group disparate batches of licit and illicit diazepam tablets using differential scanning calorimetry
Authors: Bibi S. , Bremner D. H. , Macdougall-Heasman M. , Reid R. , Simpson K. , Tough A. , Waddell S. , Stewart I. J. , Matthews K. H.
Published: August 2015

Application of Differential Scanning Calorimetry (DSC) coupled with principal component analysis for the qualitative analysis of licit and illicit diazepam tablets.
A label-free electrochemical aptasensor based on leaf-like vanadium disulfide-Au nanoparticles for the sensitive and selective detection of platelet-derived growth factor BB
Authors: Liu Xue , Shuai Hong-Lei , Huang Ke-Jing
Published: August 2015

In this work, an electrochemical aptasensor for the sensitive detection of platelet-derived growth factor BB (PDGF-BB) is fabricated based on leaf-like VS2 nanosheets which are prepared by a facile hydrothermal method.
Mycobacterium tuberculosis β-gentiobiosyl diacylglycerides signal through the pattern recognition receptor Mincle: total synthesis and structure activity relationships
Authors: Richardson Mark B. , Torigoe Shota , Yamasaki Sho , Williams Spencer J.
Published: August 2015

Gentiobiosyl diglycerides fromMycobacterium tuberculosisare shown to signal through Mincle; structure–activity relationships reveal analogues with enhanced potency.
Si–H activation by means of metal ligand cooperation in a methandiide derived carbene complex
Authors: Weismann Julia , Gessner Viktoria H.
Published: August 2015

Si–H bond activation of a series of silanes by means of metal ligand cooperation is reported.
Visible light promoted photocatalytic water oxidation: effect of metal oxide catalyst composition and light intensity
Authors: Walsh Dominic , Sanchez-Ballester Noelia M. , Ting Valeska P. , Hall Simon R. , Terry Lui R. , Weller Mark T.
Published: August 2015

Simply prepared low-cost nanoparticulate transition metal oxides were used as catalysts in visible light promoted water oxidations. The activity using daylight equivalent light intensities was assessed.
Synthesis and X-ray structure analysis of cytotoxic heptacoordinate sulfonamide salan titanium(iv)-bis-chelates
Authors: Zhao Tiankun , Grützke Martin , Götz Kathrin H. , Druzhenko Tetiana , Huhn Thomas
Published: August 2015

Two sulfonamide substituted heteroleptic salan titanium(iv)-bis-chelates showed potent anticancer activity better than cisplatin against the human carcinoma cell lines HeLa S3 and Hep G2a.
Copper nanoparticles/compounds impact agronomic and physiological parameters in cilantro (Coriandrum sativum)
Authors: Zuverza-Mena Nubia , Medina-Velo Illya A. , Barrios Ana C. , Tan Wenjuan , Peralta-Videa Jose R. , Gardea-Torresdey Jorge L.
Published: August 2015

Concentration of essential nutrients in shoots of cilantro exposed to nanosize and microsize copper compounds at 20 mg Cu per kg soil.
Agavins reverse the metabolic disorders in overweight mice through the increment of short chain fatty acids and hormones
Authors: Huazano-García Alicia , López Mercedes G.
Published: August 2015

In this study, the effects of agavins (branched fructans) along with a diet shift on metabolic parameters, short chain fatty acid (SCFA) production and gastrointestinal hormones in overweight mice were established.
Evaluation and analysis of environmentally sustainable methodologies for extraction of betulin from birch bark with a focus on industrial feasibility
Authors: Fridén Mikael E. , Jumaah Firas , Gustavsson Christer , Enmark Martin , Fornstedt Torgny , Turner Charlotta , Sjöberg Per J. R. , Samuelsson Jörgen
Published: August 2015

Evaluation and analysis of environmentally sustainable extraction of betulin from birch bark with a focus on large-scale industrial feasibility.
Naturally nano: synthesis of versatile bio-inpired monodisperse microspheres from Bacillus spores and their applications
Authors: Zeng Zhiming , Zhong Yin , Yang Huicui , Fei Ruihua , Zhou Rui , Luque Rafael , Hu Yonggang
Published: August 2015

A novel class of bionanocomposites based on monodisperse microparticles containing metal nanoparticles including Au, Pd, Ag and Pt were synthesized and characterized using a simple and efficient approach.
A high-throughput acoustic cell sorter
Authors: Ren Liqiang , Chen Yuchao , Li Peng , Mao Zhangming , Huang Po-Hsun , Rufo Joseph , Guo Feng , Wang Lin , McCoy J. Philip , Levine Stewart J. , Huang Tony Jun
Published: August 2015

We developed a standing surface acoustic wave (SSAW)-based cell sorting device. The throughput of our device has been significantly improved by using focused interdigital transducers (FIDTs) as SSAW generator.
Control of vesicle membrane permeability with catalytic particles
Authors: Jaggers Ross W. , Chen Rong , Bon Stefan A. F.
Published: August 2015

The permeability of polymer vesicles that contain membrane-embedded catalytic particles can be regulated upon exposure to a catalyst reactant.
A shape healable tough hydrogel
Authors: Wei Junhua , Wang Jilong , Su Siheng , Hasan Molla , Qiu Jingjing , Wang Shiren
Published: August 2015

The artificial meniscus made by a double network hydrogel was recovered by a two-step healing process.
Hydrogen sorption properties of Pd–Co nanoalloys embedded into mesoporous carbons
Authors: Zlotea Claudia , Ghimbeu Camelia Matei , Oumellal Yassine , Crivello Jean-Claude , Vix-Guterl Cathie , Latroche Michel
Published: August 2015

Pd–Co nanoalloys with different sizes have been embedded into mesoporous carbons. The hydrogen sorption properties show both composition and size dependence.
Two-photon uncageable enzyme inhibitors bearing targeting vectors
Authors: Anstaett Philipp , Pierroz Vanessa , Ferrari Stefano , Gasser Gilles
Published: August 2015

The activity of two cyclooxygenase-2 enzyme inhibitors, Celecoxib and Lumiracoxib, could be suppressed by coupling to photo-labile protecting groups, so-called photocages. These groups could be further functionalized with a peptide targeting vector for specific cellular delivery. The enzyme inhibition potential of the cyclooxygenase-2 inhibitors could be regained upon two-photon excitation with tissue-transparent near-IR light at 800 nm.
Preferential chiral solvation induced supramolecular chirality in optically inactive star Azo polymers: photocontrollability, chiral amplification and topological effects
Authors: Yin Lu , Zhao Yin , Jiang Shunqin , Wang Laibing , Zhang Zhengbiao , Zhu Jian , Zhang Wei , Zhu Xiulin
Published: August 2015

The chiral amplification phenomena were observed for the first time in 4- and 6-armed Azo star side-chain polymer systems, but absent in linear and 3-armed counterparts.
Behavioral study of flexible platinum counter electrodes under alternative bending conditions
Authors: He Xue-Long , Shen Ruo-Xi , Yang Guan-Jun , Li Chang-Jiu , Fang Baizeng
Published: August 2015

Pt counter electrodes with continuous and non-continuous films reveal different catalytic activities due to various bending mechanisms.
A new and efficient red phosphor for solid-state lighting: Cs2TiF6:Mn4+
Authors: Zhou Qiang , Zhou Yayun , Liu Yong , Wang Zhengliang , Chen Guo , Peng Jinhui , Yan Jing , Wu Mingmei
Published: August 2015

A new red phosphor Cs2TiF6:Mn4+has been prepared by a facile cation exchange route, which can absorb the broad blue band and emit intense red light efficiently, and can be a potential candidate for application in indoor lighting WLEDs.
Human mitochondrial MIA40 (CHCHD4) is a component of the Fe–S cluster export machinery
Authors: Murari Anjaneyulu , Thiriveedi Venkata Ramana , Mohammad Fareed , Vengaldas Viswamithra , Gorla Madhavi , Tammineni Prasad , Krishnamoorthy Thanuja , Sepuri Naresh Babu V.
Published: August 2015

Mitochondria play an essential role in synthesis and export of iron–sulfur (Fe–S) clusters to other sections of a cell. Although the mechanism of Fe–S cluster synthesis is well elucidated, information on the identity of the proteins involved in the export pathway is limited. The present study identifies hMIA40 (human mitochondrial intermembrane space import and assembly protein 40), also known as CHCHD4 (coiled-coil–helix–coiled-coil–helix domain-containing 4), as a component of the mitochondrial Fe–S cluster export machinery. hMIA40 is an iron-binding protein with the ability to bind iron in vivo and in vitro. hMIA40 harbours CPC (Cys-Pro-Cys) motif-dependent Fe–S clusters that are sensitive to oxidation. Depletion of hMIA40 results in accumulation of iron in mitochondria concomitant with decreases in the activity and stability of Fe–S-containing cytosolic enzymes. Intriguingly, overexpression of either the mitochondrial export component or cytosolic the Fe–S cluster assembly component does not have any effect on the phenotype of hMIA40-depleted cells. Taken together, our results demonstrate an indispensable role for hMIA40 for the export of Fe–S clusters from mitochondria.
Enhanced cough reflex in a model of bleomycin-induced lung fibrosis in guinea pigs
Authors: Fernández-Blanco Joan Antoni , Aguilera Mònica , Domènech Anna , Tarrasón Gema , Prats Neus , Miralpeix Montse , De Alba Jorge
Published: August 2015

Fibrotic lung diseases, such as idiopathic pulmonary fibrosis, are associated with spontaneous dry cough and hypersensitivity to tussive agents. Understanding the pathophysiology driving enhanced cough may help us to define better therapies for patients. We hypothesized that lung fibrosis induced by intratracheal bleomycin would exacerbate the cough reflex induced by tussive agents in guinea pigs. Disease progression in the lungs was characterized at days 1, 7, 14, 21 and 28 after bleomycin administration. Inflammatory and fibrotic markers, as well as neurotrophin levels, were assessed in bronchoalveolar lavage fluid and/or lung tissue. Cough sensitivity to citric acid, capsaicin and allylisothiocyanate was evaluated in conscious animals at days 14 and 21 after bleomycin administration. Pulmonary lesions evolved from an early inflammatory phase (from day 1 to day 7) to a fibrotic stage (between days 14 and 28). Fibrosis was related to increased levels of matrix metalloproteinase-2 in bronchoalveolar lavage fluid (day 21: saline, 0.26 ng/ml; bleomycin, 0.49 ng/ml). At day 14, we also observed increased cough reflexes to citric acid (163%), capsaicin (125%) and allylisothiocyanate (178%). Cough exacerbation persisted, but at a lower extent, by day 21 for capsaicin (100%) and allylisothiocyanate (54%). Moreover, bronchoalveolar lavage fluid concentrations of brain-derived neurotrophic factor, suggested to induce nerve remodelling in chronic cough, were also enhanced (day 1: saline, 14.21 pg/ml; bleomycin, 30.09 pg/ml). In summary, our model of bleomycin-induced cough exacerbation may be a valuable tool to investigate cough hypersensitivity and develop antitussive therapies for fibrotic lung diseases.
60 GHz CMOS gain‐boosted LNA with transformer feedbacked neutraliser
Authors: Kim Ki‐Jin , Lee Suk‐hui , Park Sanghoon , Ahn Kwang‐Ho
Published: August 2015

A 60 GHz low‐noise amplifier (LNA) using standard 65 nm CMOS technology is presented. A gain of the 60 GHz amplifier was boosted by using a transformer feedbacked capacitor neutraliser. To stabilise the process variations caused by the positive feedback system, the body node of the triple well was adjusted to tune the capacitor value. The theory, simulation and measurements are presented. An implementation prototype is evaluated using on‐wafer proving. The LNA showed a measured peak gain of 30 dB and a measured noise of 4.6 dB under 8.9 mW power consumption with a 1 V supply voltage. The measured IIP3 was −26 dBm. This is believed to be the first CMOS 60 GHz LNA to compensate the overlap capacitor with a single‐ended structure.
Low consumption and high frequency GaN‐based gate driver circuit with integrated PWM
Authors: Delias A. , Martin A. , Bouysse P. , Nebus J.M. , Quéré R.
Published: August 2015

A gallium nitride (GaN)‐based gate driver circuit for high power and high speed GaN power switches is presented. The principle of the proposed circuit is based upon two normally‐on GaN HEMTs and a self‐biasing resistance. An integrated pulse width modulation functionality has been implemented using the threshold effect of the presented topology. The gate driver has been built with two CGHV1F006S GaN HEMT devices from Cree, Inc. It has been connected to the gate port of a 45 W CGH40045F GaN power switch operating as a DC/DC boost converter for the purpose of demonstration. Low consumption (≈1 W) and high frequency switching operation up to 60 MHz over the 20–80% duty cycle range is demonstrated. The square waveforms having switching times in the order of nanoseconds have been measured.
Low conversion loss 94 GHz CMOS resistive mixer
Authors: Kim Jihoon , Kwon Youngwoo
Published: August 2015

A 94 GHz CMOS resistive mixer is presented using the 65 nm CMOS process. Parasitic losses which are serious at high frequencies are minimised by adopting the optimised transistor size and symmetric transistor layouts as well as a scaled‐down 65 nm CMOS technology, which contribute to reducing the conversion loss at 94 GHz by 2–3 dB, the conversion loss being 8.8–9.2 dB from 87 to 94 GHz of RF frequencies with an LO power of <7.6 dBm. To the best of the authors' knowledge, this is the best performance of CMOS resistive mixers operating in the frequency band of more than 90 GHz. The results also are competitive when compared with GaAs‐based resistive mixers having moderate LO power requirements and a reasonable noise figure.
Analysis of kink phenomenon in S11‐parameter of standard RF MOSFETs
Authors: Ahn Jahyun , Lee Seonghearn
Published: August 2015

For the first time, the low‐frequency kink phenomenon in the S11‐parameter of standard MOSFETs fabricated without any degradation of RF performances that exists in previous works is reported and its dependence on the gate finger number is analysed. The kink phenomenon is notable only for wide total gate width devices that show abrupt increase of a negative phase angle of the S11‐parameter in the low‐frequency region, because of a widening space between adjacent resistance circles in the Smith chart. This phase increase originated from a quadratic increase of the low‐frequency input capacitance against the gate finger number due to a constant load impedance for the S11‐parameter measurement.
Sub‐1100 nm lasing from post‐growth intermixed InAs/GaAs quantum‐dot lasers
Authors: Alhashim H.H. , Khan M.Z.M. , Majid M.A. , Ng T.K. , Ooi B.S.
Published: August 2015

Impurity free vacancy disordering induced highly intermixed InAs/GaAs quantum‐dot lasers are reported with high internal quantum efficiency (>89%). The lasers are shown to retain the device characteristics after intermixing and emitting in the important wavelength of ∼1070–1190 nm. The non‐coated facet Fabry‐Pērot post‐growth wavelength tuned lasers exhibits high‐power (>1.4W) and high‐gain (∼50 cm−1), suitable for applications in frequency doubled green–yellow–orange laser realisation, gas sensing, metrology etc.
High mobility transparent flexible nickel‐doped zinc oxide thin‐film transistors with small subthreshold swing
Authors: Huang Lingling , Han Dedong , Zhang Yi , Shi Pan , Yu Wen , Cui Guodong , Cong Yingying , Dong Junchen , Zhang Shengdong , Zhang Xing , Wang Yi
Published: August 2015

High‐mobility nickel (Ni)‐doped zinc oxide thin‐film transistors (NZO TFTs) have been successfully fabricated on flexible transparent plastic substrates at a low temperature. The devices all exhibited good electrical properties with small subthreshold swing (SS) and high saturation mobility fabricated under different sputtering pressure (0.4, 0.8, 1.2, 1.6 Pa) during channel deposition by RF magnetron sputtering were found. The electrical properties of NZO TFTs reached the best when the sputtering pressure was 1.6 Pa, with an SS of 89 mV/decade, a saturation mobility of 172 cm2·V−1·s−1, a drain current on/off ratio of 108, and a positive threshold voltage of 2.36 V. The results show that Ni‐doped ZnO is a promising candidate for flexible fully transparent displays.
Wideband subwavelength‐profile circularly polarised array antenna using anisotropic metasurface
Authors: Chung Kwok L. , Chaimool Sarawuth , Zhang Chunwei
Published: August 2015

A cost‐effective solution for the performance enhancement of circularly polarised array antennas by using a thin metasurface is proposed. The array is considered as reconfigurable, where an antenna engineer can arbitrarily add the metasurface onto the original array according to application requirements. Once added, the new array forms a subwavelength cavity having a compact form factor of 1.63λo × 1.63λo × 0.07λo at 2.45 GHz. The array antenna is demonstrated to have remarkable enhancement on its performance metrics including boresight gain (12.8 dBic), axial‐ratio bandwidth (46.5%) and 10 dBic gain bandwidth (24.4%). More interestingly, a sidelobe suppression level of 4.4 dB is achieved.
Stochastic subspace identification‐based approach for tracking inter‐area oscillatory modes in bulk power system utilising synchrophasor measurements
Authors: Jiang Tao , Yuan Haoyu , Jia Hongjie , Zhou Ning , Li Fangxing
Published: August 2015

Stochastic subspace identification (SSI) methods have been widely employed for oscillatory mode identification on probing and ambient data and are reported to have good performances. This work proposes a novel SSI‐based approach for identifying dominant oscillatory mode from measurement data and extends the application of SSI to ringdown condition. The proposed approach first constructs an initial cluster of eigenvalues from SSI with repetitive calculations and then utilises a novel hierarchical clustering method to extract the dominant modes from the initial cluster. The repetitive calculations within the SSI are performed through varying the model order over a range defined by a novel initial order determination process. By doing so the challenge of model order determination for SSI‐based methods is resolved. Moreover, benefiting from the repetitive calculations and the clustering process, the proposed approach is highly immune to prevalent noises in the measurements. Finally, the proposed approach is applied and validated on the field‐measurement data from the phasor measurement units of China Southern Power Grid (CSG) through comparisons with Prony, ARMAX, and Monte Carlo methods. Test results demonstrate that the proposed approach performs with high accuracy, robustness, and efficiency in CSG.
N − 1 security assessment approach based on the steady‐state security distance
Authors: Chen Sijie , Chen Qixin , Xia Qing , Zhong Haiwang , Kang Chongqing
Published: August 2015

The traditional N − 1 security assessment approaches give a limited perspective on the degree of power system security. This study proposes a novel security assessment approach using the index of post‐contingency steady‐state security distance (PCSSD). Two PCSSD models are established for contingencies causing or not causing system overloads, respectively. If the system is secure following a contingency, the PCSSD provides the shortest distance of the operating point (OP) to the post‐contingency steady‐state security region (PCSSR) boundaries, to indicate the OP's remaining security margin. If an overload condition arises after a contingency, the PCSSD provides the shortest distance of the OP to the PCSSR, to show the difficulty in eliminating power grid violations. With the index of the PCSSD, one can continuously quantify post‐contingency OPs whether they are secure or insecure and rank all possible contingencies according to their severity. The PCSSD model is a large‐scale non‐linear optimisation model which has to be calculated numerous times. A novel algorithm is proposed to improve the computational efficiency. It identifies the active boundaries of the PCSSR, and then approximates most of the PCSSDs by the corresponding ante‐contingency ones, reducing the number of optimisation problems to be solved. Case studies are performed to demonstrate the effectiveness of the proposed approach.
Loss‐of‐excitation analysis and protection for pumped‐storage machines during starting
Authors: Li Bin , Duan Zhitian , Wang Xin , Wu Jianzhong
Published: August 2015

The reversible synchronous machines in a pumped station are put into operation frequently for effective operation of the hydro pumped‐storage system. The detection of loss‐of‐excitation (LOE), which is a common failure for synchronous machines, must be guaranteed not only in normal operation, but also under starting and other possible operation conditions. A model of pumped‐storage units under the starting condition was developed using the SimPowerSystems in Matlab/Simulink. The simulation results and real tests of a pumped‐storage power plant in northeast China were presented. The LOE characteristics during starting were analysed for the first time. Since the frequency of voltage and current runs up gradually from zero to the rated frequency during starting, conventional LOE protections based on impedance under the rated frequency have to be disabled during starting. For this reason, a novel LOE protection was developed based on the R–L time‐domain model and the least‐square algorithm. Theoretical analysis and simulation tests demonstrate that the proposed LOE protection method is correct and valid.
Hydrothermal synthesis, characterisation and growth mechanism of Ni(SO4)0.3 (OH)1.4 nanowires
Authors: Wang Haoran , Wan Lei , Chen Yaqiong , Hu Wenbin , Deng Yida
Published: August 2015

A report is presented on the facile fabrication of Ni(SO4)0.3 (OH)1.4 nanowires via the hydrothermal synthesis method. The outcome demonstrates that the existence of SO42− and a comparatively lower pH are of great essence to form nanowires morphology rather than flake‐like or amorphous ones. When the molar ratio of SO42− to OH− was 1:1, almost pure nanowires of diameter 20−30 nm and several micrometres long could be obtained. Ni(SO4)0.3 (OH)1.4 is actually a type of α‐Ni(OH)2. The growth mechanism of this hydroxyl‐lacking hydroxide is discussed. The embedded SO42− between Ni(OH)2 layers can realise electrostatic equilibrium which may ensure an hcp crystal structure of Ni(OH)2 having the trend to grow along the (001) direction. On the contrary, when SO42− was superseded by other anions, the nanowires would progressively convert to nanosheets, accompanied by an α‐phase to β‐phase transformation.
Domain structures and local switching in lead-free piezoceramics Ba0.85Ca0.15Ti0.90Zr0.10O3
Authors: Turygin A. P. , Neradovskiy M. M. , Naumova N. A. , Zayats D. V. , Coondoo I. , Kholkin A. L. , Shur V. Ya.
Published: August 2015

Lead-free piezoelectrics are becoming increasingly important in view of environmental problems of currently used lead-based perovskites such as lead zirconate titanate (PZT). One of the recent candidates for PZT replacement, solid solutions of BaZr0.2Ti0.8O3 and Ba0.7Ca0.3TiO3, are investigated in this work by piezoresponse force microscopy. Coexistence of the tetragonal and rhombohedral phases in this material is observed, which probably gives rise to easy polarization switching due to multiple domain states. The period of observed domain lamella scales with the grain size obeying well-known square root dependence characteristic of BaTiO3 ceramics. Domain switching and relaxation are investigated at the nanoscale as a function of the applied voltage and duration of the applied voltage pulses. The observed distortion of piezoresponse hysteresis loops near grain boundaries is attested to the increased concentration of defects. Nanoscale piezoelectric properties of these materials are discussed.
Multidimensional dynamic piezoresponse measurements: Unraveling local relaxation behavior in relaxor-ferroelectrics via big data
Authors: Vasudevan Rama K. , Zhang Shujun , Baris Okatan M. , Jesse Stephen , Kalinin Sergei V. , Bassiri-Gharb Nazanin
Published: August 2015

Compositional and charge disorder in ferroelectric relaxors lies at the heart of the unusual properties of these systems, such as aging and non-ergodicity, polarization rotations, and a host of temperature and field-driven phase transitions. However, much information about the field-dynamics of the polarization in the prototypical ferroelectric relaxor (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) remains unprobed at the mesoscopic level. Here, we use a piezoresponse force microscopy-based dynamic multimodal relaxation spectroscopy technique, enabling the study of ferroelectric switching and polarization relaxation at mesoscopic length scales, and carry out measurements on a PMN-0.28PT sample with minimal polishing. Results indicate that beyond a threshold DC bias the average relaxation increases as the system attempts to relax to the previous state. Phenomenological fitting reveals the presence of mesoscale heterogeneity in relaxation amplitudes and clearly suggests the presence of two distinct amplitudes. Independent component analysis reveals the presence of a disorder component of the relaxation, which is found to be strongly anti-correlated with the maximum piezoresponse at that location, suggesting smaller disorder effects where the polarization reversal is large and vice versa. The disorder in the relaxation amplitudes is postulated to arise from rhombohedral and field-induced tetragonal phase in the crystal, with each phase associated with its own relaxation amplitude. These studies highlight the crucial importance of the mixture of ferroelectric phases in the compositions in proximity of the morphotropic phase boundary in governing the local response and further highlight the ability of PFM voltage and time spectroscopies, in conjunction with big-data multivariate analyses, to locally map disorder and correlate it with parameters governing the dynamic behavior.
Tip-induced domain structures and polarization switching in ferroelectric amino acid glycine
Authors: Seyedhosseini E. , Bdikin I. , Ivanov M. , Vasileva D. , Kudryavtsev A. , Rodriguez B. J. , Kholkin A. L.
Published: August 2015

Bioorganic ferroelectrics and piezoelectrics are becoming increasingly important in view of their intrinsic compatibility with biological environment and biofunctionality combined with strong piezoelectric effect and a switchable polarization at room temperature. Here, we study tip-induced domain structures and polarization switching in the smallest amino acid β-glycine, representing a broad class of non-centrosymmetric amino acids. We show that β-glycine is indeed a room-temperature ferroelectric and polarization can be switched by applying a bias to non-polar cuts via a conducting tip of atomic force microscope (AFM). Dynamics of these in-plane domains is studied as a function of an applied voltage and pulse duration. The domain shape is dictated by polarization screening at the domain boundaries and mediated by growth defects. Thermodynamic theory is applied to explain the domain propagation induced by the AFM tip. Our findings suggest that the properties of β-glycine are controlled by the charged domain walls which in turn can be manipulated by an external bias.
Quantitative phase separation in multiferroic Bi0.88Sm0.12FeO3 ceramics via piezoresponse force microscopy
Authors: Alikin D. O. , Turygin A. P. , Walker J. , Rojac T. , Shvartsman V. V. , Shur V. Ya. , Kholkin A. L.
Published: August 2015

BiFeO3 (BFO) is a classical multiferroic material with both ferroelectric and magnetic ordering at room temperature. Doping of this material with rare-earth oxides was found to be an efficient way to enhance the otherwise low piezoelectric response of unmodified BFO ceramics. In this work, we studied two types of bulk Sm-modified BFO ceramics with compositions close to the morphotropic phase boundary (MPB) prepared by different solid-state processing methods. In both samples, coexistence of polar R3c and antipolar Pbam phases was detected by conventional X-ray diffraction (XRD); the non-polar Pnma or Pbnm phase also has potential to be present due to the compositional proximity to the polar-to-non-polar phase boundary. Two approaches to separate the phases based on the piezoresponse force microscopy measurements have been proposed. The obtained fractions of the polar and non-polar/anti-polar phases were close to those determined by quantitative XRD analysis. The results thus reveal a useful method for quantitative determination of the phase composition in multi-phase ceramic systems, including the technologically most important MPB systems.
The stability of stratified spatially periodic shear flows at low Péclet number
Authors: Garaud Pascale , Gallet Basile , Bischoff Tobias
Published: August 2015

This work addresses the question of the stability of stratified, spatially periodic shear flows at low Péclet number but high Reynolds number. This little-studied limit is motivated by astrophysical systems, where the Prandtl number is often very small. Furthermore, it can be studied using a reduced set of “low-Péclet-number equations” proposed by Lignières [“The small-Péclet-number approximation in stellar radiative zones,” Astron. Astrophys. 348, 933–939 (1999)]. Through a linear stability analysis, we first determine the conditions for instability to infinitesimal perturbations. We formally extend Squire’s theorem to the low-Péclet-number equations, which shows that the first unstable mode is always two-dimensional. We then perform an energy stability analysis of the low-Péclet-number equations and prove that for a given value of the Reynolds number, above a critical strength of the stratification, any smooth periodic shear flow is stable to perturbations of arbitrary amplitude. In that parameter regime, the flow can only be laminar and turbulent mixing does not take place. Finding that the conditions for linear and energy stability are different, we thus identify a region in parameter space where finite-amplitude instabilities could exist. Using direct numerical simulations, we indeed find that the system is subject to such finite-amplitude instabilities. We determine numerically how far into the linearly stable region of parameter space turbulence can be sustained.
Direct simulation Monte Carlo investigation of the Richtmyer-Meshkov instability
Authors: Gallis M. A. , Koehler T. P. , Torczynski J. R. , Plimpton S. J.
Published: August 2015

The Richtmyer-Meshkov instability (RMI) is investigated using the Direct Simulation Monte Carlo (DSMC) method of molecular gas dynamics. Due to the inherent statistical noise and the significant computational requirements, DSMC is hardly ever applied to hydrodynamic flows. Here, DSMC RMI simulations are performed to quantify the shock-driven growth of a single-mode perturbation on the interface between two atmospheric-pressure monatomic gases prior to re-shocking as a function of the Atwood and Mach numbers. The DSMC results qualitatively reproduce all features of the RMI and are in reasonable quantitative agreement with existing theoretical and empirical models. Consistent with previous work in this field, the DSMC simulations indicate that RMI growth follows a universal behavior.
Dislocation injection in strontium titanate by femtosecond laser pulses
Authors: Titus Michael S. , Echlin McLean P. , Gumbsch Peter , Pollock Tresa M.
Published: August 2015

Femtosecond laser ablation is used in applications which require low damage surface treatments, such as serial sectioning, spectroscopy, and micromachining. However, dislocations are generated by femtosecond laser-induced shockwaves and consequently have been studied in strontium titanate (STO) using transmission electron microscopy (TEM) and electron backscatter diffraction analysis. The laser ablated surfaces in STO exhibit dislocation structures that are indicative of those produced by uniaxial compressive loading. TEM analyses of dislocations present just below the ablated surface confirm the presence of ⟨110⟩ dislocations that are of approximately 35° mixed character. The penetration depth of the dislocations varied with grain orientation relative to the surface normal, with a maximum depth of 1.5 μm. Based on the critical resolved shear stress of STO crystals, the approximate shockwave pressures experienced beneath the laser irradiated surface are reported.