bluuebunny/crossref_metadata_2025 huggingface dataset:
Duration of dual antiplatelet therapy after drug-eluting stent implantation: Meta-analysis of large randomised controlled trials
Authors: Tsoi Man-Fung , Cheung Ching-Lung , Cheung Tommy Tsang , Wong Ian Chi-Kei , Kumana Cyrus Rustam , Tse Hung-Fat , Cheung Bernard Man-Yung
Published: August 2015

Patients receive dual antiplatelet therapy (DAPT) for 6–12 months after drug-eluting stents (DES) implantation. The efficacy and safety of prolonged DAPT has been questioned. Therefore, we performed a meta-analysis on randomised trials comparing different DAPT durations. Literature was searched on trials comparing different DAPT durations. For inclusion, reports must report frequency of cardiovascular and bleeding events. Ten trials were included. Compared to 12 months, DAPT beyond 12 months was associated with fewer myocardial infarctions (OR 0.58 95%CI: 0.40–0.84) and stent thrombosis (OR 0.35 95%CI: 0.20–0.62), but more major bleeds (OR 1.60 95%CI: 1.22–2.11) and all-cause (OR 1.30 95%CI: 1.02–1.66) mortality. There was no significant alteration in risk of stroke (OR 0.93 95%CI: 0.66–1.31) or cardiac (OR 1.12 95%CI: 0.73–1.71) mortality. Compared to less than 12 months DAPT, 12 months DAPT did not reduce risk of myocardial infarction, stent thrombosis, strokes, cardiac or all-cause mortality, but increased the risk of major bleeds (OR 1.60 95%CI: 1.22–2.11). DAPT beyond 12 months reduce risk of myocardial infarction and stent thrombosis, but there is substantial increase in major bleeding risk and all-cause mortality which need to be addressed. DAPT beyond 12 months does not appear to alter the risk of stroke.
The stool microbiota of insulin resistant women with recent gestational diabetes, a high risk group for type 2 diabetes
Authors: Fugmann Marina , Breier Michaela , Rottenkolber Marietta , Banning Friederike , Ferrari Uta , Sacco Vanessa , Grallert Harald , Parhofer Klaus G. , Seissler Jochen , Clavel Thomas , Lechner Andreas
Published: August 2015

The gut microbiota has been linked to metabolic diseases. However, information on the microbiome of young adults at risk for type 2 diabetes (T2D) is lacking. The aim of this cross-sectional analysis was to investigate whether insulin resistant women with previous gestational diabetes (pGDM), a high risk group for T2D, differ in their stool microbiota from women after a normoglycemic pregnancy (controls). Bacterial communities were analyzed by high-throughput 16S rRNA gene sequencing using fecal samples from 42 pGDM and 35 control subjects 3–16 months after delivery. Clinical characterization included a 5-point OGTT, anthropometrics, clinical chemistry markers and a food frequency questionnaire. Women with a Prevotellaceae-dominated intestinal microbiome were overrepresented in the pGDM group (p < 0.0001). Additionally, the relative abundance of the phylum Firmicutes was significantly lower in women pGDM (median 48.5 vs. 56.8%; p = 0.013). Taxa richness (alpha diversity) was similar between the two groups and with correction for multiple testing we observed no significant differences on lower taxonomic levels. These results suggest that distinctive features of the intestinal microbiota are already present in young adults at risk for T2D and that further investigations of a potential pathophysiological role of gut bacteria in early T2D development are warranted.
Chronic fetal exposure to caffeine altered resistance vessel functions via RyRs-BKCa down-regulation in rat offspring
Authors: Li Na , Li Yongmei , Gao Qinqin , Li Dawei , Tang Jiaqi , Sun Miao , Zhang Pengjie , Liu Bailin , Mao Caiping , Xu Zhice
Published: August 2015

Caffeine modifies vascular/cardiac contractility. Embryonic exposure to caffeine altered cardiac functions in offspring. This study determined chronic influence of prenatal caffeine on vessel functions in offspring. Pregnant Sprague-Dawley rats (5-month-old) were exposed to high dose of caffeine, their offspring (5-month-old) were tested for vascular functions in mesenteric arteries (MA) and ion channel activities in smooth muscle cells. Prenatal exposure to caffeine increased pressor responses and vasoconstrictions to phenylephrine, accompanied by enhanced membrane depolarization. Large conductance Ca2+-activated K+ (BKCa) channels in buffering phenylephrine-induced vasoconstrictions was decreased, whole cell BKCa currents and spontaneous transient outward currents (STOCs) were decreased. Single channel recordings revealed reduced voltage/Ca2+ sensitivity of BKCa channels. BKCa α-subunit expression was unchanged, BKCa β1-subunit and sensitivity of BKCa to tamoxifen were reduced in the caffeine offspring as altered biophysical properties of BKCa in the MA. Simultaneous [Ca2+]i fluorescence and vasoconstriction testing showed reduced Ca2+, leading to diminished BKCa activation via ryanodine receptor Ca2+ release channels (RyRs), causing enhanced vascular tone. Reduced RyR1 was greater than that of RyR3. The results suggest that the altered STOCs activity in the caffeine offspring could attribute to down-regulation of RyRs-BKCa, providing new information for further understanding increased risks of hypertension in developmental origins.
Nano-encapsulated PCM via Pickering Emulsification
Authors: Wang Xuezhen , Zhang Lecheng , Yu Yi-Hsien , Jia Lisi , Sam Mannan M. , Chen Ying , Cheng Zhengdong
Published: August 2015

We designed a two-step Pickering emulsification procedure to create nano-encapsulated phase changing materials (NEPCMs) using a method whose simplicity and low energy consumption suggest promise for scale-up and mass production. Surface-modified amphiphilic zirconium phosphate (ZrP) platelets were fabricated as the Pickering emulsifiers, nonadecane was chosen as the core phase change material (PCM) and polystyrene, the shell material. The resultant capsules were submicron in size with remarkable uniformity in size distribution, which has rarely been reported. Differential scanning calorimetry (DSC) characterization showed that the capsulation efficiency of NEPCMs and they were found to be thermal stable, as characterized by the DSC data for the sample after 200 thermal cycles. NEPCMs exhibit superior mechanical stability and mobility when compared with the well-developed micro-encapsulated phase change materials (MEPCMs). NEPCMs find useful applications in thermal management, including micro-channel coolants; solar energy storage media; building temperature regulators; and thermal transfer fabrics.
One-step electrochemical preparation of a reduced graphene oxide/poly(sulfosalicylic acid) nanocomposite film for detection of acetaminophen and its application in human urine and serum studies
Authors: Zheng Bo , Li Cong , Li Yaru , Gu Yue , Yan Xiaoyi , Tang Liu , Chen Ruixue , Zhang Zhiquan
Published: August 2015

A modified GCE with reduced graphene oxide and poly(sulfosalicylic acid) nanocomposite films was synthesised by a one-step electrochemical method and applied to determine acetaminophen in human urine and serum samples.
On the reaction mechanism of redox transmetallation of elemental Yb with Hg(C6F5)2 and subsequent reactivity of Yb(C6F5)2 with pyrazole: a DFT investigation
Authors: Lefèvre Julia , Deacon Glen B. , Junk Peter C. , Maron Laurent
Published: August 2015

DFT investigations of the redox transmetallation reaction of the diorganomercurial (Hg(C6F5)2) with Yb metal, yielding Yb(C6F5)2, allowed us to define a very low energy reaction mechanism via a C6F5Yb–HgC6F5 intermediate.
The facile synthesis of hollow Au nanoflowers for synergistic chemo-photothermal cancer therapy
Authors: Li Shengnan , Zhang Lingyu , Wang Tingting , Li Lu , Wang Chungang , Su Zhongmin
Published: August 2015

A novel, mild and facile synthetic route was first developed to fabricate hollow Au nanoflowers (designated as H-AuNFs) with drug loading capacity, superior photothermal conversion property and pH/NIR dual-responsive drug delivery performance for chemo-photothermal synergistic cancer therapy in vitro and in vivo.
An alternative synthesis of the breast cancer drug fulvestrant (Faslodex®): catalyst control over C–C bond formation
Authors: Caprioglio Diego , Fletcher Stephen P.
Published: August 2015

We report a four-step synthesis of the important breast cancer drug fulvestrant through a copper-catalyzed 1,6-addition that avoids Grignard reagents.
Differential behaviour of cationic triphenylamine derivatives in fixed and living cells: triggering and imaging cell death
Authors: Chennoufi R. , Bougherara H. , Gagey-Eilstein N. , Dumat B. , Henry E. , Subra F. , Mahuteau-Betzer F. , Tauc P. , Teulade-Fichou M.-P. , Deprez E.
Published: August 2015

Nuclear staining by cationic triphenylamines is spontaneous in fixed cells while a cytoplasm–nucleus translocation is strictly dependent on light illumination in living cells and concomitant to a fast cell death process.
Redox cycling-amplified enzymatic Ag deposition and its application in the highly sensitive detection of creatine kinase-MB
Authors: Jiaul Haque Al-Monsur , Kim Jihye , Dutta Gorachand , Kim Sinyoung , Yang Haesik
Published: August 2015

This communication reports a novel enzymatic Ag-deposition scheme combined with chemical–chemical redox cycling by reduced β-nicotinamide adenine dinucleotide.
Activation of CO2by ionic liquid EMIM–BF4in the electrochemical system: a theoretical study
Authors: Wang Yuanqing , Hatakeyama Makoto , Ogata Koji , Wakabayashi Masamitsu , Jin Fangming , Nakamura Shinichiro
Published: August 2015

The electrochemical reduction of CO2to CO by an ionic liquid EMIM–BF4is one of the most promising CO2reduction processes proposed so far with its high Faradaic efficiency and low overpotential.
Observation of the retarded transportation of a photogenerated hole on epitaxial graphene
Authors: Wang Shujie , Yuan Xizhi , Bi Xiaofeng , Wang Xiaomei , Huang Qingsong
Published: August 2015

In alkaline solution, epitaxial graphene retards the transportation of photogenerated holes from a SiC substrate.
Identifying the major intermediate species by combining time-resolved X-ray solution scattering and X-ray absorption spectroscopy
Authors: Kim Kyung Hwan , Kim Jeongho , Oang Key Young , Lee Jae Hyuk , Grolimund Daniel , Milne Christopher J. , Penfold Thomas J. , Johnson Steven L. , Galler Andreas , Kim Tae Wu , Kim Jong Goo , Suh Deokbeom , Moon Jiwon , Kim Joonghan , Hong Kiryong , Guérin Laurent , Kim Tae Kyu , Wulff Michael , Bressler Christian , Ihee Hyotcherl
Published: August 2015

We identify a major transient species formed in the photolysis of CHI3 by combining time-resolved X-ray liquidography (TRXL) and time-resolved X-ray absorption spectroscopy (TR-XAS).
Microstructural characteristics of natural gas hydrates hosted in various sand sediments
Authors: Zhao Jiafei , Yang Lei , Liu Yu , Song Yongchen
Published: August 2015

Natural gas hydrates form as floating model in pores, without being affected by grain sizes and sand wettability.
An advanced approach for measuring acidity of hydroxyls in confined space: a FTIR study of low-temperature CO and15N2adsorption on MOF samples from the MIL-53(Al) series
Authors: Mihaylov M. , Andonova S. , Chakarova K. , Vimont A. , Ivanova E. , Drenchev N. , Hadjiivanov K.
Published: August 2015

The combined use of CO and N2as IR probe molecules allows a precise measuring of the acidity of OH groups that are preliminary involved in weak H-bonding.
Correction: The strength and directionality of a halogen bond are co-determined by the magnitude and size of the σ-hole
Authors: Kolář Michal , Hostaš Jiří , Hobza Pavel
Published: August 2015

Correction for 'The strength and directionality of a halogen bond are co-determined by the magnitude and size of the σ-hole' by Michal Kolář et al., Phys. Chem. Chem. Phys., 2014, 16, 9987–9996.
Potential of Cu–saponite catalysts for soot combustion
Authors: Gebretsadik F. B. , Cesteros Y. , Salagre P. , Giménez-Mañogil J. , García-García A. , Bueno-López A.
Published: August 2015

A variety of H– and Na–saponite supports have been prepared by several synthesis approaches; the best activity for soot combustion was achieved with copper oxide supported on a Na–saponite prepared at pH 13 and with surfactant.
In situ fabrication of Ce1−xLaxO2−δ/palygorskite nanocomposites for efficient catalytic oxidation of CO: effect of La doping
Authors: Li Xiazhang , Ni Chaoying , Lu Xiaowang , Zuo Shixiang , Liu Wenjie , Yao Chao
Published: August 2015

Novel palygorskite (PG) supported Ce1−xLaxO2−δ nanocomposites were prepared by a facile in situ deposition method for efficient catalytic oxidation of CO and the effect of La doping was evaluated.
Mild partial deoxygenation of esters catalyzed by an oxazolinylborate-coordinated rhodium silylene
Authors: Xu Songchen , Boschen Jeffery S. , Biswas Abhranil , Kobayashi Takeshi , Pruski Marek , Windus Theresa L. , Sadow Aaron D.
Published: August 2015

An oxazoline-stabilized rhodium silylene complex catalyzes the deoxygenation of carbonyls using PhSiH3as the reductant, including esters to ethers, amides to amines, and ketones to hydrocarbons rapidly at room temperature.
Influence of milk fermented with Lactobacillus rhamnosus NCDC 17 alone and in combination with herbal ingredients on diet induced adiposity and related gene expression in C57BL/6J mice
Authors: Pothuraju Ramesh , Sharma Raj Kumar , Chagalamarri Jayasimha , Kavadi Praveen Kumar , Jangra Surender
Published: August 2015

Obesity has become a major health problem in developed countries and is rapidly catching up in the developing world due to changes in their life style.
Iron-catalysed oxidative cleavage of lignin and β-O-4 lignin model compounds with peroxides in DMSO
Authors: Mottweiler Jakob , Rinesch Torsten , Besson Claire , Buendia Julien , Bolm Carsten
Published: August 2015

Simple FeCl3-derived iron catalysts are used for the cleavage of lignin and β-O-4 lignin model compounds.
Structural insights into tumor-specific chaperoning activity of gamma synuclein in protecting estrogen receptor alpha 36 and its role in tamoxifen resistance in breast cancer
Authors: Panneerselvam Manivel , Muthu Kannan , Ramadas Krishna
Published: August 2015

This study investigates structural aspects underlying the chaperoning activity of an intrinsically disordered protein, gamma synuclein, in promoting estrogen mediated breast cancer.
A study on the effective substance of the Wu-tou formula based on the metabonomic method using UPLC-Q-TOF-HDMS
Authors: Xu Tengfei , Liu Shu , Zhao Jiadi , Feng Guifang , Pi Zifeng , Song Fengrui , Liu Zhiqiang
Published: August 2015

To elucidate the mechanisms of five single herbs in the Wu-tou Formula, the treatment effects were evaluated on AIA rats based on the pathological variation, serum biochemical parameters and using a metabonomic method.
Controllable synthesis of micro/nano-structured MnCo2O4 with multiporous core–shell architectures as high-performance anode materials for lithium-ion batteries
Authors: Wu Xiaoyu , Li Songmei , Wang Bo , Liu Jianhua , Yu Mei
Published: August 2015

Various micro/nano-structured MnCo2O4 with excellent lithium storage performance were synthesized controllably.
Synthesis of BiOI/Bi4O5I2/Bi2O2CO3p–n–p heterojunctions with superior photocatalytic activities
Authors: Peng Yin , Yu Pian-Pian , Zhou Hai-Yan , Xu An-Wu
Published: August 2015

The formation of p–n heterojunctions among BiOI, Bi4O5I2and Bi2O2CO3enhances the charge transfer and separation of the photogenerated carriers and photocatalytic activity.
Template-free synthesis of Fe3O4 nanorod bundles and their highly efficient peroxidase mimetic activity for the degradation of organic dye pollutants with H2O2
Authors: Bhuyan Diganta , Arbuj Sudhir S. , Saikia Lakshi
Published: August 2015

The high surface to volume ratio of Fe3O4 nanorods facilitates the excellent activation of H2O2 for the photo-Fenton-like degradation of crystal violet dye under solar light.
Dual-mode chemodosimetric response of dibromo-BODIPY with anions
Authors: Raja Sekhar Adiki , Kaloo Masood Ayoub , Sankar Jeyaraman
Published: August 2015

Fluorometric response of dibromo-BODIPY to various anions.
Pyrimidinedione-mediated selective histone deacetylase 6 inhibitors with antitumor activity in colorectal cancer HCT116 cells
Authors: Liu Yi-Min , Lee Hsueh-Yun , Lai Mei-Jung , Pan Shiow-Lin , Huang Hsiang-Ling , Kuo Fei-Chiao , Chen Mei-Chuan , Liou Jing-Ping
Published: August 2015

We synthesized a series of pyrimidinedione derivatives and evaluated their activities.
One-pot approach to synthesize hyperbranched poly(thiol–ether amine) (hPtEA) through sequential “thiol–ene” and “epoxy–amine” click reactions
Authors: Yu Jing , Su Zhilong , Xu Hongjie , Ma Xiaodong , Yin Jie , Jiang Xuesong
Published: August 2015

We demonstrated a one-pot approach to synthesize hyperbranched poly(thiol–ether amine) (hPtEA) through sequential “thiol–ene” and “epoxy–amine” click reactions, both of which were well traced using in situ1H-NMR spectra.
Uniform distribution of low content BaTiO3 nanoparticles in poly(vinylidene fluoride) nanocomposite: toward high dielectric breakdown strength and energy storage density
Authors: Hou Yafang , Deng Yuan , Wang Yao , Gao HongLi
Published: August 2015

The uniform distribution of low content nanofillers in polymer nanocomposites was achieved to maximize energy storage with improved breakdown strength and simultaneously increased the relative dielectric constant.
Heteroepitaxial TiO2@W-doped VO2 core/shell nanocrystal films: preparation, characterization, and application as bifunctional window coatings
Authors: Lan Shi-Di , Chang Chi-Jung , Huang Chih-Feng , Chen Jem-Kun
Published: August 2015

We employed rutile TiO2 nanoparticles (TiNPs) as cores for coating with vanadium sols to grow the VO2(M) heteroepitaxially as shells. Needle-like structures gradually appeared on the TiNP surfaces after a sintering process.
Synthesis of heterocycles and fused heterocycles catalyzed by nanomaterials
Authors: Elwahy Ahmed H. M. , Shaaban Mohamed R.
Published: August 2015

The application of nanomaterials as heterogeneous catalyst for the synthesis of different heterocyclic systems is reviewed.
Mechanism of Pd-catalyzed C(sp3)–H activation of aliphatic amines: an insight from DFT calculations
Authors: Zhang Ye , Qi Zheng-Hang , Ruan Gui-Yu , Zhang Yi , Liu Wei , Wang Yong
Published: August 2015

DFT studies on Pd-catalyzed C(sp3)–H activation of aliphatic amines have been performed using the B3LYP functional. The rate- and regio-determining step of the catalytic cycle is deprotonation of the Cmethyl–H bond through a six-membered cyclopalladation transition state.
POSS-based hybrid cationic copolymers with low aggregation potential for efficient gene delivery
Authors: Jiang Shan , Poh Ying Zhou , Loh Xian Jun
Published: August 2015

This work describes the synthesis and application of POSS-based copolymers with low aggregation potential for efficient gene delivery.
A series of tunable emission phosphors of Sm3+, Eu3+ and Mn2+ doped Ba3Tb(PO4)3: luminescence and energy transfer
Authors: Li Ting , Li Panlai , Wang Zhijun , Xu Shuchao , Bai Qiongyu , Yang Zhiping
Published: August 2015

A series of activator Sm3+, Eu3+, Mn2+ ion doped Ba3Tb(PO4)3 phosphors with tunable emitting color were synthesized via the high temperature solid state method.
Fabrication of Fe3O4@SiO2@RGO nanocomposites and their excellent absorption properties with low filler content
Authors: Pan Ya-Fei , Wang Guang-Sheng , Yue Yong-Hai
Published: August 2015

The minimum reflection loss of Fe3O4@SiO2@RGO nanocomposites can reach −26.6 dB at 9.7 GHz with low filler content; the mechanism was also explained.
Two-step spin crossover behaviour in the chiral one-dimensional coordination polymer [Fe(HAT)(NCS)2]∞
Authors: Romero-Morcillo Tania , Valverde-Muñoz Francisco J. , Muñoz M. Carmen , Herrera Juan Manuel , Colacio Enrique , Real José A.
Published: August 2015

Two-step spin crossover behaviour with large stabilisation of the intermediate state in a chiral one-dimensional coordination polymer.
Deep blue organic light-emitting devices enabled by bipolar phenanthro[9,10-d]imidazole derivatives
Authors: Chen Shuo , Wu Yukun , Zhao Yi , Fang Daining
Published: August 2015

Novel phenanthroimidazole derivatives with D–π–A structures have been successfully designed and prepared. Non-doped organic light emitting diodes (OLEDs) were fabricated by employing the compounds, which display deep blue emission.
A sky-blue fluorescent small molecule for non-doped OLED using solution-processing
Authors: Tang Fu , Peng Jinghong , Liu Ronghua , Yao Chuang , Xu Xinjun , Li Lidong
Published: August 2015

A sky-blue fluorescent small molecule was employed to fabricate the non-doped emissive layer of solution-processed OLED.
Silicon(i) chemistry: the NHC-stabilised silicon(i) halides Si2X2(Idipp)2(X = Br, I) and the disilicon(i)-iodido cation [Si2(I)(Idipp)2]+
Authors: Arz Marius I. , Geiß Daniel , Straßmann Martin , Schnakenburg Gregor , Filippou Alexander C.
Published: August 2015

An efficient method for the synthesis of the NHC-stabilised Si(i) halides Si2X2(Idipp)2(2-X, X = Cl, Br, I) was developed, which involves the oxidation of Si2(Idipp)2(1) with 1,2-dihaloethanes. Iodide abstraction from2-Iafforded the unprecedented silicon(i) salt [Si2(I)(Idipp)2][B(C6F5)4] (3).
Supramolecular hydrogels constructed by red-light-responsive host–guest interactions for photo-controlled protein release in deep tissue
Authors: Wang Dongsheng , Wagner Manfred , Butt Hans-Jürgen , Wu Si
Published: August 2015

The red-light-responsive supramolecular interaction between tetra-ortho-methoxy-substituted azobenzene and β-cyclodextrin (β-CD) is demonstrated.
Synthesis and electrochemical properties of Li3V2(P1−xBxO4)3/C cathode materials
Authors: Feng Kai , Cheng Yi , Wang Meiri , Zhang Hongzhang , Li Xianfeng , Zhang Huamin
Published: August 2015

A promising cathode material Li3V2(P1−xBxO4)3/C for high-power Li rechargeable batteries shows excellent electrochemical performance.
Visible light-driven novel g-C3N4/NiFe-LDH composite photocatalyst with enhanced photocatalytic activity towards water oxidation and reduction reaction
Authors: Nayak Susanginee , Mohapatra Lagnamayee , Parida Kulamani
Published: August 2015

Dispersion of exfoliated CN over the surface of exfoliated LDH composite materials, and its photocatalytic water splitting under visible-light irradiation.
Structural, electrochemical and magnetic properties of a novel KFeSO4F polymorph
Authors: Lander Laura , Rousse Gwenaëlle , Abakumov Artem M. , Sougrati Moulay , van Tendeloo Gustaaf , Tarascon Jean-Marie
Published: August 2015

A new monoclinic KFeSO4F polymorph is stabilized with an average working potential of 3.7 V and a possible magnetoelectric behavior.
Flexible cyclic siloxane core enhances the transfection efficiency of polyethylenimine-based non-viral gene vectors
Authors: Uritu Cristina M. , Calin Manuela , Maier Stelian S. , Cojocaru Corneliu , Nicolescu Alina , Peptanariu Dragos , Constantinescu Cristina Ana , Stan Daniela , Barboiu Mihail , Pinteala Mariana
Published: August 2015

cD4H–AGE–PEI conjugates, with a favorable balance between hydrophilic and hydrophobic moieties, are promising carriers for gene delivery.
Band gap control and transformation of monolayer-MoS2-based hetero-bilayers
Authors: Li X. D. , Wu S. Q. , Zhu Z. Z.
Published: August 2015

Tunable band gaps of MoS2-based hetero-bilayers can be realized by changing the interlayer spacing or employing in-plane compressing/stretching.
Partially thermostated Kac model
Authors: Tossounian Hagop , Vaidyanathan Ranjini
Published: August 2015

We study a system of N particles interacting through the Kac collision, with m of them interacting, in addition, with a Maxwellian thermostat at temperature 1β. We use two indicators to understand the approach to the equilibrium Gaussian state. We prove that (i) the spectral gap of the evolution operator behaves as mN for large N and (ii) the relative entropy approaches its equilibrium value (at least) at an eventually exponential rate ∼mN2 for large N. The question of having non-zero entropy production at time 0 remains open. A relationship between the Maxwellian thermostat and the thermostat used in the work of Bonetto et al. [J. Stat. Phys. 156(4), 647–667 (2014)] is established through a Van Hove limit.
Nonlinear dead water resistance at subcritical speed
Authors: Grue John
Published: August 2015

The dead water resistance F1=12CdwρSU2 (ρ fluid density, U ship speed, S wetted body surface, Cdw resistance coefficient) on a ship moving at subcritical speed along the upper layer of a two-layer fluid is calculated by a strongly nonlinear method assuming potential flow in each layer. The ship dimensions correspond to those of the Polar ship Fram. The ship draught, b0, is varied in the range 0.25h0–0.9h0 (h0 the upper layer depth). The calculations show that Cdw/(b0/h0)2 depends on the Froude number only, in the range close to critical speed, Fr = U/c0 ∼ 0.875–1.125 (c0 the linear internal long wave speed), irrespective of the ship draught. The function Cdw/(b0/h0)2 attains a maximum at subcritical Froude number depending on the draught. Maximum Cdw/(b0/h0)2 becomes 0.15 for Fr = 0.76, b0/h0 = 0.9, and 0.16 for Fr = 0.74, b0/h0 = 1, where the latter extrapolated value of the dead water resistance coefficient is about 60 times higher than the frictional drag coefficient and relevant for the historical dead water observations. The nonlinear Cdw significantly exceeds linear theory (Fr < 0.85). The ship generated waves have a wave height comparable to the upper layer depth. Calculations of three-dimensional wave patterns at critical speed compare well to available laboratory experiments. Upstream solitary waves are generated in a wave tank of finite width, when the layer depths differ, causing an oscillation of the force. In a wide ocean, a very wide wave system develops at critical speed. The force approaches a constant value for increasing time.
Kinetic theory of turbulence for parallel propagation revisited: Formal results
Authors: Yoon Peter H.
Published: August 2015

In a recent paper, Gaelzer et al. [Phys. Plasmas 22, 032310 (2015)] revisited the second-order nonlinear kinetic theory for turbulence propagating in directions parallel/anti-parallel to the ambient magnetic field. The original work was according to Yoon and Fang [Phys. Plasmas 15, 122312 (2008)], but Gaelzer et al. noted that the terms pertaining to discrete-particle effects in Yoon and Fang's theory did not enjoy proper dimensionality. The purpose of Gaelzer et al. was to restore the dimensional consistency associated with such terms. However, Gaelzer et al. was concerned only with linear wave-particle interaction terms. The present paper completes the analysis by considering the dimensional correction to nonlinear wave-particle interaction terms in the wave kinetic equation.
Graphene as a hexagonal 2-lattice: Evaluation of the in-plane material constants for the linear theory. A multiscale approach
Authors: Sfyris D. , Koukaras E. N. , Pugno N. , Galiotis C.
Published: August 2015

Continuum modeling of free-standing graphene monolayer, viewed as a two dimensional 2-lattice, requires specification of the components of the shift vector that acts as an auxiliary variable. If only in-plane motions are considered, the energy depends on an in-plane strain measure and the shift vector. The assumption of geometrical and material linearity leads to quadratic energy terms with respect to the shift vector, the strain tensor, and their combinations. Graphene's hexagonal symmetry reduces the number of independent moduli then to four. We evaluate these four material parameters using molecular calculations and the adaptive intermolecular reactive empirical bond order potential and compare them with standard linear elastic constitutive modeling. The results of our calculations show that the predicted values are in reasonable agreement with those obtained solely from our molecular calculations as well as those from the literature. To the best of our knowledge, this is the first attempt to measure mechanical properties when graphene is modeled as a hexagonal 2-lattice. This work targets at the continuum scale when the insight measurements come from finer scales using atomistic simulations.
Parabolized Stability Equations analysis of nonlinear interactions with forced eigenmodes to control subsonic jet instabilities
Authors: Itasse Maxime , Brazier Jean-Philippe , Léon Olivier , Casalis Grégoire
Published: August 2015

Nonlinear evolution of disturbances in an axisymmetric, high subsonic, high Reynolds number hot jet with forced eigenmodes is studied using the Parabolized Stability Equations (PSE) approach to understand how modes interact with one another. Both frequency and azimuthal harmonic interactions are analyzed by setting up one or two modes at higher initial amplitudes and various phases. While single mode excitation leads to harmonic growth and jet noise amplification, controlling the evolution of a specific mode has been made possible by forcing two modes (m1, n1), (m2, n2), such that the difference in azimuth and in frequency matches the desired “target” mode (m1 − m2, n1 − n2). A careful setup of the initial amplitudes and phases of the forced modes, defined as the “killer” modes, has allowed the minimizing of the initially dominant instability in the near pressure field, as well as its estimated radiated noise with a 15 dB loss. Although an increase of the overall sound pressure has been found in the range of azimuth and frequency analyzed, the present paper reveals the possibility to make the initially dominant instability ineffective acoustically using nonlinear interactions with forced eigenmodes.
Dielectric functions and carrier concentrations of Hg1−xCdxSe films determined by spectroscopic ellipsometry
Authors: Lee A. J. , Peiris F. C. , Brill G. , Doyle K. , Myers T. H.
Published: August 2015

Spectroscopic ellipsometry, ranging from 35 meV to 6 eV, was used to determine the dielectric functions of a series of molecular beam epitaxy-grown Hg1−xCdxSe thin films deposited on both ZnTe/Si(112) and GaSb(112) substrates. The fundamental band gap as well as two higher-order electronic transitions blue-shift with increasing Cd composition in Hg1−xCdxSe, as expected. Representing the free carrier absorption with a Drude oscillator, we found that the effective masses of Hg1−xCdxSe (grown on ZnTe/Si) vary between 0.028 and 0.050 times the free electron mass, calculated using the values of carrier concentration and the mobility obtained through Hall measurements. Using these effective masses, we determined the carrier concentrations of Hg1−xCdxSe samples grown on GaSb, which is of significance as films grown on such doped-substrates posit ambiguous results when measured by conventional Hall experiments. These models can serve as a basis for monitoring Cd-composition during sample growth through in-situ spectroscopic ellipsometry.
Electronic and thermoelectric properties of van der Waals materials with ring-shaped valence bands
Authors: Wickramaratne Darshana , Zahid Ferdows , Lake Roger K.
Published: August 2015

The valence band of a variety of few-layer, two-dimensional materials consist of a ring of states in the Brillouin zone. The energy-momentum relation has the form of a “Mexican hat” or a Rashba dispersion. The two-dimensional density of states is singular at or near the band edge, and the band-edge density of modes turns on nearly abruptly as a step function. The large band-edge density of modes enhances the Seebeck coefficient, the power factor, and the thermoelectric figure of merit ZT. Electronic and thermoelectric properties are determined from ab initio calculations for few-layer III–VI materials GaS, GaSe, InS, InSe, for Bi2Se3, for monolayer Bi, and for bilayer graphene as a function of vertical field. The effect of interlayer coupling on these properties in few-layer III–VI materials and Bi2Se3 is described. Analytical models provide insight into the layer dependent trends that are relatively consistent for all of these few-layer materials. Vertically biased bilayer graphene could serve as an experimental test-bed for measuring these effects.
A self-assembled metamaterial for Lamb waves
Authors: Khanolkar A. , Wallen S. , Abi Ghanem M. , Jenks J. , Vogel N. , Boechler N.
Published: August 2015

We report the design and characterization of a self-assembled, locally resonant acoustic metamaterial for Lamb waves, composed of a monolayer of 1.02 μm polystyrene microspheres adhered to a 1.27 μm thick free-standing silicon membrane. A laser-induced transient grating technique is used to generate Lamb waves in the metamaterial and to measure its acoustic response. The measurements reveal a microsphere contact resonance and the lowest frequency spheroidal microsphere resonance. The measured dispersion curves show hybridization of flexural Lamb waves with the microsphere contact resonance. We compare the measured dispersion with an analytical model using the contact resonance frequency as a single fitting parameter, and find that it well describes the observed hybridization. This study may lead to an improved understanding of microscale contact mechanics and to the design of new types of acoustic metamaterials.
Modeling of electrically controlled molecular diffusion in a nanofluidic channel
Authors: Kim Sungho , Ozalp Ece Isenbike , Sundar Vignesh , Zhu Jian-Gang , Weldon Jeffrey A.
Published: August 2015

The objective of this work is to understand and quantitatively model the diffusive transport in electrically gated nanofluidic channels suitable for applications in drug delivery. Specifically, this work analyzed gated molecular diffusion through simulation in nanochannels between two chambers with asymmetric concentrations under a number of different control variables including surface charge, channel structure, drug molecule charge number, and background ionic concentration. When the dimension of the fluidic channel is comparable to the thickness of electrical double layer, the potential generated by gating inside of the channel becomes significant, which allows control of charged molecular diffusion inside of the nanochannel through electrostatic repulsion and attraction. In this work, the diffusion of molecules through a nanochannel is simulated in planar and cylindrical nanochannels when applying a gate voltage in two different surface charging scenarios. The gated nanochannel structures were modeled in the finite element software (COMSOL Multiphysics). The simulation results indicate that a small applied voltage can alter the diffusion rate by many orders of magnitude under certain conditions. The cylindrical nanochannel showed the best control of diffusion of charged molecules due to the exclusion-enrichment effect inside the nanochannel.
Heterointegration of InGaAs/GaAs quantum wells on micro-patterned Si substrates
Authors: Jung A. , Taboada A. G. , Stumpf W. , Kreiliger T. , Isa F. , Isella G. , Barthazy Meier E. , von Känel H.
Published: August 2015

InGaAs/GaAs quantum wells (QWs) grown on μ-patterned Ge/Si substrates by metal organic vapor phase epitaxy are investigated by electron microscopy and spatially resolved photoluminescence (PL) spectroscopy. The lattice parameter mismatch of GaAs and Si is overcome by a Ge buffer layer grown by low-energy plasma enhanced chemical vapor deposition. The GaAs crystals form truncated pyramids whose shape is strongly affected by the geometry of the underlying pattern consisting of 8 μm deep and 3–50 μm wide square Si pillars. Comparing the measured PL energies with calculations performed in the effective mass approximation reveals that the QW emission energies are significantly influenced by the GaAs morphology. It is shown that the geometry favors indium diffusion during growth from the inclined facets towards the top (001) facet. The Si pillar-size dependent release of thermally induced strain observed in the PL measurements is confirmed by X-ray diffraction.
Influence of internal electric fields on band gaps in short period GaN/GaAlN and InGaN/GaN polar superlattices
Authors: Gorczyca I. , Skrobas K. , Suski T. , Christensen N. E. , Svane A.
Published: August 2015

The electronic structures of short period mGaN/nGayAl1−yN and mInyGa1-yN/nGaN superlattices grown along the wurtzite c axis have been calculated for different alloy compositions y and various small numbers m of well- and n of barrier-monolayers. The general trends in gap behavior can, to a large extent, be related to the strength of the internal electric field, E, in the GaN and InGaN quantum wells. In the GaN/GaAlN superlattices, E reaches 4 MV/cm, while in the InGaN/GaN superlattices, values as high as E ≈ 6.5 MV/cm are found. The strong electric fields are caused by spontaneous and piezoelectric polarizations, the latter contribution dominating in InGaN/GaN superlattices. The influence of different arrangements of In atoms (indium clustering) on the band gap values in InGaN/GaN superlattices is examined.
Beyond spatial correlation effect in micro-Raman light scattering: An example of zinc-blende GaN/GaAs hetero-interface
Authors: Ning J. Q. , Zheng C. C. , Zheng L. X. , Xu S. J.
Published: August 2015

Spatially resolved Raman light scattering experiments were performed on a zinc-blende GaN/GaAs heterostructure with confocal micro-Raman scattering technique under the backscattering geometric configuration. By varying the illumination spot locations across the heterostructure interface, we found that the Raman light scattering spectral features change remarkably. The interface effect on the GaAs substrate manifested as a much broader lineshape of the transverse optical (TO) phonon mode. Two kinds of broadening mechanisms, namely, spatial correlation induced wave-vector relaxation effect and lattice-mismatch strain + compositional intermixing effect, have been identified. The former leads to the broadening of the TO mode at the low-energy side, whereas the latter accounts for the broadening at the high-energy side. The diffuse light scattering from the highly defective nucleation layer of GaN was found to produce a broad scattering background of the GaN TO mode. The methodology and conclusions of the present work could be applicable to Raman spectroscopic studies on other material interfaces.
Time-resolved measurements of Cooper-pair radiative recombination in InAs quantum dots
Authors: Mou S. S. , Irie H. , Asano Y. , Akahane K. , Nakajima H. , Kumano H. , Sasaki M. , Murayama A. , Suemune I.
Published: August 2015

We studied InAs quantum dots (QDs) where electron Cooper pairs penetrate from an adjacent niobium (Nb) superconductor with the proximity effect. With time-resolved luminescence measurements at the wavelength around 1550 nm, we observed luminescence enhancement and reduction of luminescence decay time constants at temperature below the superconducting critical temperature (TC) of Nb. On the basis of these measurements, we propose a method to determine the contribution of Cooper-pair recombination in InAs QDs. We show that the luminescence enhancement measured below TC is well explained with our theory including Cooper-pair recombination.
Effect of the out-of-plane stress on the properties of epitaxial SrTiO3 films with nano-pillar array on Si-substrate
Authors: Bai Gang , Xie Qiyun , Liu Zhiguo , Wu Dongmei
Published: August 2015

A nonlinear thermodynamic formalism has been proposed to calculate the physical properties of the epitaxial SrTiO3 films containing vertical nano-pillar array on Si-substrate. The out-of-plane stress induced by the mismatch between film and nano-pillars provides an effective way to tune the physical properties of ferroelectric SrTiO3 films. Tensile out-of-plane stress raises the phase transition temperature and increases the out-of-plane polarization, but decreases the out-of-plane dielectric constant below Curie temperature, pyroelectric coefficient, and piezoelectric coefficient. These results showed that by properly controlling the out-of-plane stress, the out-of-plane stress induced paraelectric-ferroelectric phase transformation will appear near room temperature. Excellent dielectric, pyroelectric, piezoelectric properties of these SrTiO3 films similar to PZT and other lead-based ferroelectrics can be expected.
Spin- and valley-coupled electronic states in monolayer WSe2 on bilayer graphene
Authors: Sugawara K. , Sato T. , Tanaka Y. , Souma S. , Takahashi T.
Published: August 2015

We have fabricated a high-quality monolayer WSe2 film on bilayer graphene by epitaxial growth and revealed the electronic states by spin- and angle-resolved photoemission spectroscopy. We observed a direct energy gap at the Brillouin-zone corner in contrast to the indirect nature of gap in bulk WSe2, which is attributed to the lack of interlayer interaction and the breaking of space-inversion symmetry in monolayer film. A giant spin splitting of ∼0.5 eV, which is the largest among known monolayer transition-metal dichalcogenides, is observed in the energy band around the zone corner. The present results suggest a high potential applicability of WSe2 to develop advanced devices based with the coupling of spin- and valley-degrees of freedom.
Joule heating effect in nonpolar and bipolar resistive random access memory
Authors: Uenuma Mutsunori , Ishikawa Yasuaki , Uraoka Yukiharu
Published: August 2015

The position of the conductive filament (CF) and the heating behaviour during a switching process in nonpolar and bipolar resistive random access memories (ReRAMs) were evaluated using thermal analysis. The position of the CF was clearly observed from Joule heating at the surface of the electrode on the CF. The position of the CF did not change during the switching cycle, except in the case of an unstable CF. In the nonpolar ReRAM, spike-shaped temperature increments were observed during both the forming and the set processes because of the overshoot current. However, the behaviour of the temperature increment in the bipolar ReRAM was virtually consistent with the profile of the electrical power.
Demonstration of a three-dimensional photonic crystal nanocavity in a ⟨110⟩-layered diamond structure
Authors: Tajiri T. , Takahashi S. , Ota Y. , Tatebayashi J. , Iwamoto S. , Arakawa Y.
Published: August 2015

We experimentally demonstrate a three-dimensional photonic crystal (3D PC) nanocavity in a ⟨110⟩-layered diamond structure with a quality factor (Q-factor) of 12 800 at a wavelength of 1.1 μm. The observed Q is 1.2 times higher than that of a 3D PC nanocavity in a woodpile structure with the same in-plane size and the same number of stacked layers. This result indicates the potential importance of the ⟨110⟩-layered diamond structure for getting high Q 3D PC nanocavities within a limited in-plane space.
Magnetophoretic potential at the movement of cluster products of electrochemical reactions in an inhomogeneous magnetic field
Authors: Gorobets O. Yu. , Gorobets Yu. I. , Rospotniuk V. P.
Published: August 2015

An electric field arises from the influence of a nonuniform static magnetic field on charged colloid particles with magnetic susceptibility different from that of the surrounding liquid. It arises, for example, under the influence of a nonuniform static magnetic field in clusters of electrochemical reaction products created during metal etching, deposition, and corrosion processes without an external electric current passing through an electrolyte near a magnetized electrode surface. The corresponding potential consists of a Nernst potential of inhomogeneous distribution of concentration of colloid particles and a magnetophoretic potential (MPP). This potential has been calculated using a thermodynamic approach based on the equations of thermodynamics of nonequilibrium systems and the Onsager relations for a mass flow of correlated magnetic clusters under a gradient magnetic force in the electrolyte. The conditions under which the MPP contribution to the total electric potential may be significant are discussed with a reference to the example of a corroding spherical ferromagnetic steel electrode.
Tuning piezoresistive transduction in nanomechanical resonators by geometrical asymmetries
Authors: Llobet J. , Sansa M. , Lorenzoni M. , Borrisé X. , San Paulo A. , Pérez-Murano F.
Published: August 2015

The effect of geometrical asymmetries on the piezoresistive transduction in suspended double clamped beam nanomechanical resonators is investigated. Tapered silicon nano-beams, fabricated using a fast and flexible prototyping method, are employed to determine how the asymmetry affects the transduced piezoresistive signal for different mechanical resonant modes. This effect is attributed to the modulation of the strain in pre-strained double clamped beams, and it is confirmed by means of finite element simulations.
Magnetic trap effect to restrict motion of self-powered tiny liquid metal motors
Authors: Tan Si-Cong , Gui Han , Yuan Bin , Liu Jing
Published: August 2015

We reported a phenomenon that the magnetic field can make up a boundary to restrict motion of the aluminum powered liquid metal motor. For the droplet motors with diameter below 1 mm, such magnetic trap effect will be strong enough to bounce them off the boundary. We attributed the effect to the electromagnetic mechanism. Owing to the Lorentz force, the high magnetic field will break up the directional running of the motor. The more aluminum added in the metal droplet, the stronger the trap effect. This phenomenon suggests an important way to control behavior of the liquid metal motors.
Tunable surface acoustic wave device based on acoustoelectric interaction in ZnO/GaN heterostructures
Authors: Li Rui , Reyes Pavel I. , Ragavendiran Sowmya , Shen H. , Lu Yicheng
Published: August 2015

A tunable surface acoustic wave (SAW) device is developed on a multilayer structure which consists of an n-type semiconductor ZnO layer and a Ni-doped piezoelectric ZnO layer deposited on a GaN/c-Al2O3 substrate. The unique acoustic dispersion relationship between ZnO and GaN generates the multi-mode SAW response in this structure, facilitating high frequency operation. A dc bias voltage is applied to a Ti/Au gate layer deposited on the path of SAW delay line to modulate the electrical conductivity for tuning the acoustic velocity. For devices operating at 1.25 GHz, a maximum SAW velocity change of 0.9% is achieved, equivalent to the frequency change of 11.2 MHz. This voltage-controlled frequency tuning device has potential applications in resettable sensors, adaptive signal processing, and secure wireless communication.
Stacking order dependent mechanical properties of graphene/MoS2 bilayer and trilayer heterostructures
Authors: Elder Robert M. , Neupane Mahesh R. , Chantawansri Tanya L.
Published: August 2015

Transition metal dichalcogenides (TMDC) such as molybdenum disulfide (MoS2) are two-dimensional materials that show promise for flexible electronics and piezoelectric applications, but their weak mechanical strength is a barrier to practical use. In this work, we perform nanoindentation simulations using atomistic molecular dynamics to study the mechanical properties of heterostructures formed by combining MoS2 with graphene. We consider both bi- and tri-layer heterostructures formed with MoS2 either supported or encapsulated by graphene. Mechanical properties, such as Young's modulus, bending modulus, ultimate tensile strength, and fracture strain, are extracted from nanoindentation simulations and compared to the monolayer and homogeneous bilayer systems. We observed that the heterostructures, regardless of the stacking order, are mechanically more robust than the mono- and bi-layer MoS2, mainly due to the mechanical reinforcement provided by the graphene layer. The magnitudes of ultimate strength and fracture strain are similar for both the bi- and tri-layer heterostructures, but substantially larger than either the mono- and bi-layer MoS2. Our results demonstrate the potential of graphene-based heterostructures to improve the mechanical properties of TMDC materials.