bluuebunny/crossref_metadata_2025 huggingface dataset:
Aggregates of a hetero-oligophenylene derivative as reactors for the generation of palladium nanoparticles: a potential catalyst in the Sonogashira coupling reaction under aerial conditions
Authors: Walia Preet Kamal , Pramanik Subhamay , Bhalla Vandana , Kumar Manoj
Published: September 2015

Hetero-oligophenylene derivative3stabilized Pd nanoparticles serve as an excellent catalyst in a copper/amine free Sonogashira coupling reaction under aerial conditions at room temperature.
Aggregation-induced emission fluorogens as biomarkers to assess the viability of microalgae in aquatic ecosystems
Authors: Guo Feng , Gai Wei-Ping , Hong Yuning , Tang Ben Zhong , Qin Jianguang , Tang Youhong
Published: September 2015

An aggregation-induced emission fluorogen is reported as a novel tool to differentiate dead and live microalgae and quantify the link between live algal concentration and fluorogen intensity for monitoring water pollution in the environment.
Magnetic ionic liquids as PCR-compatible solvents for DNA extraction from biological samples
Authors: Clark Kevin D. , Yamsek Melissa M. , Nacham Omprakash , Anderson Jared L.
Published: September 2015

A novel strategy for the rapid detection of bacterial plasmid DNA preconcentrated by hydrophobic magnetic ionic liquids (MILs) is described.
Alternating chiral selectivity of aldol reactions under the confined space of mesoporous silica
Authors: Yeh Chewei , Sun Yan-Ru , Huang Shing-Jong , Tsai Yeun-Min , Cheng Soofin
Published: September 2015

The chiral selectivities were altered and high diastereo- and enantio-selectivities of the products were obtained in water medium without adding acid co-catalysts when a primary–tertiary diamine catalyst was immobilized on mesoporous SBA-15 to form a recyclable catalyst for the direct asymmetric aldol reaction of cyclohexanone with p-nitrobenzaldehyde.
Reactivity differences of Sc3N@C2n (2n = 68 and 80). Synthesis of the first methanofullerene derivatives of Sc3N@D5h-C80
Authors: Cerón Maira R. , Izquierdo Marta , Alegret Núria , Valdez Juan A. , Rodríguez-Fortea Antonio , Olmstead Marilyn M. , Balch Alan L. , Poblet Josep M. , Echegoyen Luis
Published: September 2015

Based on the chemical reactivity differences between Sc3N@D5h-C80 and Sc3N@D3-C68, Sc3N@D5h-C80 was isolated and functionalized, giving rise to five new methano-derivatives.
Solvent diffusion through a non-porous crystal ‘caught in the act’ and related single-crystal-to-single-crystal transformations in a cationic dinuclear Ag(i) complex
Authors: Alen Jo , Van Meervelt Luc , Dehaen Wim , Dobrzańska Liliana
Published: September 2015

A few snapshots of a dynamic solvent diffusion process through a seemingly non-porous crystal of a dinuclear, cyclic Ag(i) complex were revealed. These indicate the complexity of the process, which involves not only relocation of the molecules in the crystal lattice, but also conformational adjustments of the metallocycles in response to solvent uptake/release.
Nanometer-scale hydrogen ‘portals’ for the control of magnesium hydride formation
Authors: Chung Chia-Jung , Nivargi Chinmay , Clemens Bruce
Published: September 2015

Our unique ‘nanoportal’ structure of Pd nanoparticles deposited on epitaxial Mg thin films allows the study of MgH2 formation kinetics in a controlled way.
Unusual liquid–liquid phase transition in aqueous mixtures of a well-known dendrimer
Authors: da Costa Viviana C. P. , Annunziata Onofrio
Published: September 2015

Salt induces liquid–liquid phase separation (LLPS) of the aqueous solutions of a dendrimer. LLPS occurs by cooling at low salt concentration and by heating at high salt concentration.
Characterization of SiC-grown epitaxial graphene microislands using tip-enhanced Raman spectroscopy
Authors: Vantasin Sanpon , Tanaka Yoshito , Uemura Shohei , Suzuki Toshiaki , Kutsuma Yasunori , Doujima Daichi , Kaneko Tadaaki , Ozaki Yukihiro
Published: September 2015

Tip-enhanced Raman spectroscopy of the nanoridge of a graphene island.
Synthesis and crystal structure of a new hexagonal perovskite 7H-Ba7Li1.75Mn3.5O15.75with Mn4+/Mn5+charge distribution
Authors: Tarakina N. V. , Tyutyunnik A. P. , Bazuev G. V. , Vasilev A. D. , Gould C. , Nikolaenko I. V. , Berger I. F.
Published: September 2015

Our work describes the synthesis and crystal structure of a new hexagonal perovskite 7H-Ba7Li1.75Mn3.5O15.75with Mn4+/Mn5+charge distribution.
Design and synthesis of a chiral uranium-based microporous metal organic framework with high SHG efficiency and sequestration potential for low-valent actinides
Authors: Wang Yanlong , Li Yuxiang , Bai Zhuanling , Xiao Chengliang , Liu Zhiyong , Liu Wei , Chen Lanhua , He Weiwei , Diwu Juan , Chai Zhifang , Albrecht-Schmitt Thomas E. , Wang Shuao
Published: September 2015

Microporous SCU-3 is synthesized with high SHG efficiency and Th4+ sequestration potential.
Luminescent pentafluorophenyl-cycloplatinated complexes: synthesis, characterization, photophysics, cytotoxicity and cellular imaging
Authors: Berenguer J. R. , Pichel J. G. , Giménez N. , Lalinde E. , Moreno M. T. , Piñeiro-Hermida S.
Published: September 2015

Pentafluorophenyl cycloplatinated complexes have been synthesized and their photophysical properties studied and investigated by DFT, TD-DFT calculations. The cellular localization and the cytotoxicity of [Pt(C^N)(C6F5)(DMSO)] complexes towards two different cell lines has been assessed.
Influence of Y3+, Gd3+, and Lu3+ co-doping on the phase and luminescence properties of monoclinic Eu:LaVO4 particles
Authors: Van Deun Rik , D'hooge Micheline , Savic Aleksandar , Van Driessche Isabel , Van Hecke Kristof , Kaczmarek Anna M.
Published: September 2015

Enhancement of the luminescence properties of Eu3+ doped monoclinic LaVO4 nanoparticles was investigated through co-doping with Y3+, Gd3+ and Lu3+ ions.
Spatial distribution of phases during gradual magnetostructural transitions in copper(ii)–nitroxide based molecular magnets
Authors: Fedin Matvey V. , Veber Sergey L. , Bagryanskaya Elena G. , Romanenko Galina V. , Ovcharenko Victor I.
Published: September 2015

A thorough analysis of EPR and XRD data led to conclusions on the spatial distribution of phases in copper–nitroxide molecular magnets.
A selectively exposed crystal facet-engineered TiO2 thin film photoanode for the higher performance of the photoelectrochemical water splitting reaction
Authors: Kim Chang Woo , Yeob So Jin , Cheng Hui-Ming , Kang Young Soo
Published: September 2015

A selectively exposed (101)-crystal facet engineered TiO2 photoanode is investigated for the higher efficiency of the hydrogen evolution reaction.
Simulation of the dissolved nitrogen and phosphorus loads in different land uses in the Three Gorges Reservoir Region—based on the improved export coefficient model
Authors: Wang Jinliang , Shao Jing'an , Wang Dan , Ni Jiupai , Xie Deti
Published: September 2015

Nonpoint source pollution is one of the primary causes of eutrophication of water bodies.
The effect of recombinant human lactoferrin from the milk of transgenic cows on Salmonella enterica serovar typhimurium infection in mice
Authors: Wu Jinghuan , Hu Yujie , Du Chunming , Piao Jianhua , Yang Lichen , Yang Xiaoguang
Published: September 2015

Recombinant human lactoferrin from the milk of transgenic cows has an antibacterial effect of alleviating infection againstSalmonella entericaserovartyphimuriumin BALB/c mice.
Nuclease stability of boron-modified nucleic acids: application to label-free mismatch detection
Authors: Reverte Maëva , Vasseur Jean-Jacques , Smietana Michael
Published: September 2015

Boronic acid modified DNA emerged as a new class of resistant oligonucleotides against enzymatic degradation. This property has been used to develop an enzyme-assisted label free method for mismatch detection.
A highly efficient Mukaiyama–Mannich reaction of N-Boc isatin ketimines and other active cyclic ketimines using difluoroenol silyl ethers catalyzed by Ph3PAuOTf
Authors: Yu Jin-Sheng , Zhou Jian
Published: September 2015

A Ph3PAuOTf catalyzed highly efficient reaction of difluoroenoxysilanes and active ketimines is reported, which represents the first Au(i)-catalyzed Mukaiyama–Mannich reaction.
Synthesis of polymers with densely-grafted oligo(ethylene glycol)s by Pd-initiated polymerization of oxyethylene-containing diazoacetates
Authors: Shimomoto Hiroaki , Shimizu Kohta , Takeda Chiharu , Kikuchi Misaki , Kudo Tomohiko , Mukai Hiroto , Itoh Tomomichi , Ihara Eiji , Hoshikawa Naohiro , Koiwai Akihiko , Hasegawa Naoki
Published: September 2015

The polymers with densely-grafted OEGs showed higher LCSTs and Li-ion conductivities than the corresponding vinyl polymers.
New oxovanadium(iv) complexes with pincer ligand obtained in situ: experimental and theoretical studies on the structure, spectroscopic properties and antitumour activity
Authors: Adach Anna , Daszkiewicz Marek , Tyszka-Czochara Małgorzata , Barszcz Bolesław
Published: September 2015

Experimental and theoretical studies on the structure and spectroscopic properties of two complexes: [VOL1(NCS)2] (1) and [VOL1(NCS)2]·C6H5CH3 (2) where L1-N,N-bis(3,5-dimethylpyrazol-1-ylmethyl)amine have been reported.
CdS nanorod–MFe2O4 (M = Zn, Co and Ni) nanocomposites: a heterojunction synthesis strategy to mitigate environmental deterioration
Authors: Singh Charanjit , Devika Devika , Malik Rupal , Kumar Vinod , Singhal Sonal
Published: September 2015

Fabrication of CdS nanorods encrusted with MFe2O4 nanoparticles (M = Zn, Co and Ni) gives magneto-luminescence nanocomposites with magnetically separable and visible light driven photocatalytic properties.
Heparin-modified graphene oxide loading anti-cancer drug and growth factor with heat stability, long-term release property and lower cytotoxicity
Authors: Wu Ting , Zhang Bin , Liang Yuanyuan , Liu Tao , Bu Jinyan , Lin Lixing , Wu Zhimin , Liu Hongxi , Wen Shuiping , Tan Shaozao , Cai Xiang
Published: September 2015

Heparin-modified graphene oxide was prepared as the carrier of anti-cancer drugs and growth factor with long-term release property, reduced cytotoxicity and improved heat stability.
Poly-assisted template-free synthesis of novel double-shelled Co3O4 yolk–shell submicrospheres with excellent electrochemical properties
Authors: Dong Yujuan , Wei Huiying , Bi Huifang , Liu Wei , Zhang Wenjing , Yang Yanzhao
Published: September 2015

Novel double-shelled Co3O4 yolk–shell submicrospheres were successfully synthesized via a poly-assisted template-free solvothermal method and a subsequent high heat-treatment process.
Synthesis and characterization of pH-responsive nanohydrogels as biocompatible drug carriers based on chemically modified tragacanth gum polysaccharide
Authors: Hemmati Khadijeh , Masoumi Arameh , Ghaemy Mousa
Published: September 2015

In this work, the preparation and application of pH-responsive nanohydrogels based on tragacanth gum polysaccharide and glycidyl methacrylate were investigated.
A nitrogen and sulfur co-doped graphene-supported nickel tetrapyridyloxyphthalocyanine hybrid fabricated by a solvothermal method and its application for the detection of bisphenol A
Authors: Zhang Bowen , Wang Yishu , Dai Xvhong , Liu Dajun , He Xingquan
Published: September 2015

A novel hybrid consisting of nickel tetrapyridyloxyphthalocyanine (NiTPPc) and nitrogen and sulfur co-doped graphene (N-S-G) was obtainedviaa solvothermal method and applied for the determination of BPA.
Structures and third-order nonlinear optical properties of two three-dimensional Cd(ii) coordination polymers with trinodal (3, 4, 5) and dinodal (4, 5) connected network topologies
Authors: Lian Zhaoxun , Jiang Kai , Lou Tianjun
Published: September 2015

We reported two Cd(ii) coordination polymers with trinodal (3, 4, 5) and dinodal (4, 5) connected network topologies. Two compounds exhibit very strong NLO absorption in thin films and solution.
Synthesis of porous gold nanoparticle/MoS2 nanocomposites based on redox reactions
Authors: Yu Xiaojing , Shiraki Tomohiro , Yang Shengchun , Ding Bingjun , Nakashima Naotoshi
Published: September 2015

We develop a facile method for preparing the porous gold nanoparticles (Au-NPs)/2H-form MoS2 nanocomposite that forms a unique 3-dimensional structure and shows a high surface enhanced Raman spectroscopy effect.
Preparation and performance of antibacterial layer-by-layer polyelectrolyte nanofiltration membranes based on metal–ligand coordination interactions
Authors: Zhen Hongyan , Wang Tingting , Jia Rui , Su Baowei , Gao Congjie
Published: September 2015

Coordinative nanofiltration membranes with commendable antibacterial property and hydrophilicity are prepared and investigated extensively by alternating LBL assembly of polyethyleneimine and polystyrene sulfonate using Cu2+ as coordination agent.
Controlling the electro-mechanical performance of polypyrrole through 3- and 3,4-methyl substituted copolymers
Authors: Melling D. , Wilson S. A. , Jager E. W. H.
Published: September 2015

A unique study of the impact of crosslinking on the electro-mechanical performance of electropolymerised polypyrrole films using laser-scanning micrometry.
Hydroxyapatite nanoparticles on dendritic α-Fe2O3 hierarchical architectures for a heterogeneous photocatalyst and adsorption of Pb(ii) ions from industrial wastewater
Authors: Bharath G. , Ponpandian N.
Published: September 2015

A facile surfactant free hydrothermal process was used to prepare dendritic α-Fe2O3 and hydroxyapatite (HAp) nanoparticles dispersed on dendritic α-Fe2O3 nanostructures used for dye degradation and Pb(ii) ions removal from industrial wastewater.
Preparation and characterization of PEG-g-MWCNTs/PSf nano-hybrid membranes with hydrophilicity and antifouling properties
Authors: Wang Wen-Yi , Shi Jing-Yuan , Wang Jin-Long , Li Yan-Ling , Gao Ning-Ning , Liu Zheng-Xin , Lian Wei-Tao
Published: September 2015

MWCNTs were successfully functionalized with PEG. PEG-g-MWCNTs/PSf membranes showed higher hydrophilicity and good antifouling capability. The nano-hybrid membranes exhibited excellent mechanical properties.
Prenylated flavonoids from the fruits of Sinopodophyllum emodi and their cytotoxic activities
Authors: Sun Yan-Jun , Hao Zhi-You , Si Jin-Guang , Wang Yu , Zhang Yan-Li , Wang Jun-Min , Gao Mei-Ling , Chen Hui
Published: September 2015

Thirteen new prenylated flavonoids were isolated from Sinopodophyllum emodi together with eleven known analogues. Compound 22 exhibited the most potent cytotoxicity against MCF-7 and HepG2 cell lines.
Binding thermodynamics and kinetics guided optimization of potent Keap1–Nrf2 peptide inhibitors
Authors: Lu Meng-Chen , Chen Zhi-Yun , Wang Ya-Lou , Jiang Yong-Lin , Yuan Zhen-Wei , You Qi-Dong , Jiang Zheng-Yu
Published: September 2015

Activation of Nrf2 by directly inhibiting the Keap1–Nrf2 Protein–Protein Interaction (PPI) has gained research interest with regard to developing novel agents for treating inflammatory related diseases.
Large-area MoS2 thin layers directly synthesized on Pyramid-Si substrate for surface-enhanced Raman scattering
Authors: Qiu Hengwei , Li Zhen , Gao Saisai , Chen Peixi , Zhang Chao , Jiang Shouzhen , Xu Shicai , Yang Cheng , Li Hongsheng
Published: September 2015

In our work, we directly synthesized few layer MoS2 on a pyramid-Si substrate to fabricate a surface-enhanced Raman scattering (SERS) substrate via thermally decomposing the precursor of ammonium thiomolybdate ((NH4)2MoS4).
Effects of ferric nitrate additions under different pH conditions on autothermal thermophilic aerobic digestion for sewage sludge
Authors: Jin Ningben , Shou Zongqi , Yuan Haiping , Lou Ziyang , Zhu Nanwen
Published: September 2015

Effects of ferric nitrate additions under different pH conditions on disinhibition of excessive VFAs for enhancement of ATAD performance.
Mechanistic insight into the aerobic oxidation of benzyl alcohol catalyzed by the CuII–TEMPO catalyst in alkaline water solution
Authors: Duan R. F. , Cheng L. , Zhang Q. C. , Ma L. S. , Ma H. Y. , Yang J. C.
Published: September 2015

The benzyl alcohol oxidation to benzaldehyde in the alkaline water solution catalyzed by CuII/L–TEMPO catalyst is investigated by density functional method. The favorable mechanisms and the role for the water ​have also been predicted.
The design and investigation of the self-assembly of dimers with two nematic phases
Authors: Ahmed Z. , Welch C. , Mehl G. H.
Published: September 2015

Non-symmetric nematic dimers are designed and investigated by OPM, DSC and XRD; assembly models for the Nxphase are developed.
A semi-empirical analysis of dye adsorption and electron transport in dye sensitized solar cells (DSSCs)
Authors: Ameri Mohsen , Samavat Feridoun , Mohajerani Ezeddin
Published: September 2015

Experiments and modeling of dye adsorption and electron transport characteristics with respect to photoanode thickness were performed to elucidate the dye adsorption parameters and their relation with the structural and transport properties of DSSCs.
Mixed systems to assist enzymatic ring opening polymerization of lactide stereoisomers
Authors: Duchiron S. W. , Pollet E. , Givry S. , Avérous L.
Published: September 2015

Enzymatic ring opening polymerization of both enantiomers of lactide was performed in toluene. The eROP was kinetically improved by solvent assisted method (by TEA) and gave 6 time faster reaction.
Highly efficient, selective, and durable photocatalytic system for CO2 reduction to formic acid
Authors: Tamaki Yusuke , Koike Kazuhide , Ishitani Osamu
Published: September 2015

Photocatalytic reduction of CO2 to formic acid with high efficiency, durability, and rate.
Photocatalytic C–F alkylation; facile access to multifluorinated arenes
Authors: Singh A. , Kubik J. J. , Weaver J. D.
Published: September 2015

From the top down; access to complex multifluorinated arenes via multiple photocatalytic C–F substitutions.
A local mode picture for H atom reaction with vibrationally excited H2O: a full dimensional state-to-state quantum dynamics investigation
Authors: Liu Shu , Zhang Dong H.
Published: September 2015

Here we report the first full-dimensional state-to-state study for the title reaction with H2O in the ground and the first symmetric and asymmetric stretching excited states..
Mechanism of the CuII-catalyzed benzylic oxygenation of (aryl)(heteroaryl)methanes with oxygen
Authors: Sterckx Hans , De Houwer Johan , Mensch Carl , Caretti Ignacio , Tehrani Kourosch Abbaspour , Herrebout Wouter A. , Van Doorslaer Sabine , Maes Bert U. W.
Published: September 2015

A mechanistic study of the copper-catalyzed oxidation of the methylene group of aryl(di)azinylmethanes was performed.
Tuning thermoelectric performance by nanostructure evolution of a conducting polymer
Authors: Hu Xincheng , Chen Guangming , Wang Xin , Wang Hanfu
Published: September 2015

The thermoelectric performance of PEDOT can be conveniently and effectively tuned by nanostructure evolution.
Proliferation and functionality of human umbilical vein endothelial cells on angiopoietin-1 immobilized 316L stainless steel
Authors: Li Xin , Yuan Shuheng , Chen Si , Luo Rifang , Xiong Kaiqin , Yang Zhilu , Wang Jin , Huang Nan
Published: September 2015

An angiopoietin-1 functionalized surface was establishedviapolydopamine coating and regulated HUVECs survival, proliferation and function.
Novel protein-loaded chondroitin sulfate-N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan nanoparticles with reverse zeta potential: preparation, characterization, and ex vivo assessment
Authors: Tsai Tsung-Neng , Yen Hui-Ju , Chen Cheng-cheung , Chen Ying-chuan , Young Yen-an , Cheng Kuang-ming , Young Jenn-jong , Hong Po-da
Published: September 2015

Positively and negatively surface charged nanoparticles were prepared by a facile PEC method composed of chondroitin sulfate andN-[(2-hydroxy-3-trimethylammonium)propyl]chitosan.
PARK7/DJ-1 dysregulation by oxidative stress leads to magnesium deficiency: implications in degenerative and chronic diseases
Authors: Kolisek Martin , Montezano Augusto C. , Sponder Gerhard , Anagnostopoulou Aikaterini , Vormann Juergen , Touyz Rhian M. , Aschenbach Joerg R.
Published: September 2015

Disturbed magnesium (Mg2+) homoeostasis and increased levels of OS (oxidative stress) are associated with poor clinical outcomes in patients suffering from neurodegenerative, cardiovascular and metabolic diseases. Data from clinical and animal studies suggest that MD (Mg2+ deficiency) is correlated with increased production of ROS (reactive oxygen species) in cells, but a straightforward causal relationship (including molecular mechanisms) between the two conditions is lacking. The multifactorial protein PARK7/DJ-1 is a major antioxidant protein, playing a key role in cellular redox homoeostasis, and is a positive regulator of AR (androgen receptor)-dependent transcription. SLC41A1 (solute carrier family 41 member 1), the gene encoding a ubiquitous cellular Mg2+E (Mg2+efflux) system, has been shown to be regulated by activated AR. We hypothesize that overexpression/up-regulation of PARK7/DJ-1, attributable to OS and related activation of AR, is an important event regulating the expression of SLC41A1 and consequently, modulating the Mg2+E capacity. This would involve changes in the transcriptional activity of PARK7/DJ-1, AR and SLC41A1, which may serve as biomarkers of intracellular MD and may have clinical relevance. Imipramine, in use as an antidepressant, has been shown to reduce the Mg2+E activity of SLC41A1 and OS. We therefore hypothesize further that administration of imipramine or related drugs will be beneficial in MD- and OS-associated diseases, especially when combined with Mg2+ supplementation. If proved true, the OS-responsive functional axis, PARK7/DJ-1–AR–SLC41A1, may be a putative mechanism underlying intracellular MD secondary to OS caused by pro-oxidative stimuli, including extracellular MD. Furthermore, it will advance our understanding of the link between OS and MD.
miR-21 promotes renal fibrosis in diabetic nephropathy by targeting PTEN and SMAD7
Authors: McClelland Aaron D. , Herman-Edelstein Michal , Komers Radko , Jha Jay C. , Winbanks Catherine E. , Hagiwara Shinji , Gregorevic Paul , Kantharidis Phillip , Cooper Mark E.
Published: September 2015

The cytokine transforming growth factor (TGF)-β1 plays a central role in diabetic nephropathy (DN) with data implicating the miRNA (miR) miR-21 as a key modulator of its prosclerotic actions. In the present study, we demonstrate data indicating that miR-21 up-regulation positively correlates with the severity of fibrosis and rate of decline in renal function in human DN. Furthermore, concomitant analyses of various models of fibrotic renal disease and experimental DN, confirm tubular miR-21 up-regulation. The fibrotic changes associated with increased miR-21 levels are proposed to include the regulation of TGF-β1-mediated mothers against decapentaplegic homolog 3 (SMAD3)- and phosphoinositide 3-kinase (PI3K)-dependent signalling pathways via co-ordinated repression of mothers against decapentaplegic homolog 7 (SMAD7) and phosphatase and tensin homologue (PTEN) respectively. This represents a previously uncharacterized interaction axis between miR-21 and PTEN–SMAD7. Targeting of these proteins by miR-21 resulted in de-repression of the respective pathways as reflected by increases in SMAD3 and V-Akt murine thymoma viral oncogene homolog 1 (AKT) phosphorylation. Many of the changes typically induced by TGF-β1, including phosphorylation of signalling mediators, were further enhanced by miR-21. Collectively, these data present a unified model for a key role for miR-21 in the regulation of renal tubular extracellular matrix (ECM) synthesis and accumulation and provide important insights into the molecular pathways implicated in the progression of DN.
Implementation of phase disposition modulation method for the three‐level diode‐clamped matrix converter
Authors: Dan Hanbing , Peng Tao , Su Mei , Sun Yao , Zhang Guanguan , Xiong Wenjing
Published: September 2015

To improve the input and output waveform quality in terms of total harmonic distortion (THD) for the three‐level diode‐clamped matrix converter topology, the phase disposition carrier‐based modulation method is a good option. However, it is difficult to implement because of the loss of zero‐current commutations. Aiming at addressing the problem above, a hybrid switching sequence for the phase disposition method is presented to realise the safe commutation, and a prediction‐based method is used to alternate the switching sequences. The current direction information of the switches in cascaded rectifier for commutations is obtained by a current reconstruction method. As demonstrated by experimental results, the phase disposition method contributes to lower input and output waveforms THD values compared with the phase opposition disposition method.
Modular symmetric and asymmetric reduced count switch multilevel current source inverter
Authors: Najmi Ebrahim Seifi , Ajami Ali
Published: September 2015

Current source inverters (CSIs) have prominent features compared to voltage source inverters. The CSIs are less affected by grid voltage fluctuations, their control is simple and they have inherent short‐circuit protection. This study proposes a novel multilevel CSI based on modular cells. The proposed topology is performed based on the parallel connection of two‐switch modules. According to the value of current sources in each module, the proposed configuration can be operated in two modes of operation: symmetric and asymmetric. A comparison study is carried out between the proposed topology, the cascaded H‐bridge and a recently developed topology in terms of the number of switches, the number of sources, total switch device power, and power losses. The comparison study shows a great improvement in performance of the proposed symmetric and asymmetric topologies compared to conventional structures. In addition, the proposed circuit shows an interesting feature which is the common emitter connection of the main switches. This arrangement leads to simple gate drive circuits. Finally, seven‐level symmetric topology and fifteen‐level asymmetric topology are simulated and the laboratory prototypes of them are implemented. The presented simulation and experimental results validate the feasibility of proposed topologies.
Nonlinear observer to estimate polarization phenomenon in membrane distillation
Authors: Khoukhi Billal , Tadjine Mohamed , Boucherit Mohamed Seghir
Published: September 2015

This paper presents a bi-dimensional dynamic model of Direct Contact Membrane Desalination (DCMD) process. Most of the MD configuration processes have been modeled as steady-state one-dimensional systems. Stationary two-dimensional MD models have been considered only in very few studies. In this work, a dynamic model of a DCMD process is developed. The model is implemented using Matlab/Simulink environment. Numerical simulations are conducted for different operational parameters at the module inlets such as the feed and permeate temperature or feed and permeate flow rate. The results are compared with experimental data published in the literature. The work presents also a feed forward control that compensates the possible decrease of the temperature gradient by increasing the flow rate. This work also deals with a development of nonlinear observer to estimate temperature polarization inside the membrane. The observer gives a good profile and longitudinal temperature estimations and shows a good prediction of pure water flux production.
Effect of initial perturbation amplitude on Richtmyer-Meshkov flows induced by strong shocks
Authors: Dell Z. , Stellingwerf R. F. , Abarzhi S. I.
Published: September 2015

We systematically study the effect of the initial perturbation on Richtmyer-Meshkov (RM) flows induced by strong shocks in fluids with contrasting densities. Smooth Particle Hydrodynamics simulations are employed. A broad range of shock strengths and density ratios is considered. The amplitude of the initial single mode sinusoidal perturbation of the interface varies from 0% to 100% of its wavelength. The simulations results are compared, wherever possible, with four rigorous theories, and with other experiments and simulations, achieving good quantitative and qualitative agreement. Our study is focused on early time dynamics of the Richtmyer-Meshkov instability (RMI). We analyze the initial growth-rate of RMI immediately after the shock passage, when the perturbation amplitude increases linearly with time. For the first time, to the authors' knowledge, we find that the initial growth-rate of RMI is a non-monotone function of the initial perturbation amplitude, thus restraining the amount of energy that can be deposited by the shock at the interface. The maximum value of the initial growth-rate depends on the shock strength and the density ratio, whereas the corresponding value of the initial perturbation amplitude depends only slightly on the shock strength and density ratio.
Dynamic tunneling force microscopy for characterizing electronic trap states in non-conductive surfaces
Authors: Wang R. , Williams C. C.
Published: September 2015

Dynamic tunneling force microscopy (DTFM) is a scanning probe technique for real space mapping and characterization of individual electronic trap states in non-conductive films with atomic scale spatial resolution. The method is based upon the quantum mechanical tunneling of a single electron back and forth between a metallic atomic force microscopy tip and individual trap states in completely non-conducting surface. This single electron shuttling is measured by detecting the electrostatic force induced on the probe tip at the shuttling frequency. In this paper, the physical basis for the DTFM method is unfolded through a physical model and a derivation of the dynamic tunneling signal as a function of several experimental parameters is shown. Experimental data are compared with the theoretical simulations, showing quantitative consistency and verifying the physical model used. The experimental system is described and representative imaging results are shown.
Hole transport assisted by the piezoelectric field in In0.4Ga0.6N/GaN quantum wells under electrical injection
Authors: Zhang Shuailong , Xie Enyuan , Yan Tongxing , Yang Wei , Herrnsdof Johannes , Gong Zheng , Watson Ian M. , Gu Erdan , Dawson Martin D. , Hu Xiaodong
Published: September 2015

The authors observe the significant penetration of electrically injected holes through InGaN/GaN quantum wells (QWs) with an indium mole fraction of 40%. This effect and its current density dependence were analysed by studies on micro-pixel light-emitting diodes, which allowed current densities to be varied over a wide range up to 5 kA/cm2. The systematic changes in electroluminescence spectra are discussed in the light of the piezoelectric field in the high-indium-content QWs and its screening by the carriers. Simulations were also carried out to clarify the unusual hole transport mechanism and the underlying physics in these high-indium QWs.
Spectral reconstruction analysis for enhancing signal-to-noise in time-resolved spectroscopies
Authors: Wilhelm Michael J. , Smith Jonathan M. , Dai Hai-Lung
Published: September 2015

We demonstrate a new spectral analysis for the enhancement of the signal-to-noise ratio (SNR) in time-resolved spectroscopies. Unlike the simple linear average which produces a single representative spectrum with enhanced SNR, this Spectral Reconstruction analysis (SRa) improves the SNR (by a factor of ca. 0.6n) for all n experimentally recorded time-resolved spectra. SRa operates by eliminating noise in the temporal domain, thereby attenuating noise in the spectral domain, as follows: Temporal profiles at each measured frequency are fit to a generic mathematical function that best represents the temporal evolution; spectra at each time are then reconstructed with data points from the fitted profiles. The SRa method is validated with simulated control spectral data sets. Finally, we apply SRa to two distinct experimentally measured sets of time-resolved IR emission spectra: (1) UV photolysis of carbonyl cyanide and (2) UV photolysis of vinyl cyanide.
Flip channel: A microfluidic device for uniform-sized embryoid body formation and differentiation
Authors: Chen Ying-Hua , Peng Chien-Chung , Tung Yi-Chung
Published: September 2015

This paper reports a two-layered polydimethylsiloxane microfluidic device—Flip channel, capable of forming uniform-sized embryoid bodies (EBs) and performing stem cell differentiation within the same device after flipping the microfluidic channel. The size of EBs can be well controlled by designing the device geometries, and EBs with multiple sizes can be formed within a single device to study EB size-dependent stem cell differentiation. During operation of the device, cells are positioned in the designed positions. As a result, observation and monitoring specific population of cells can be achieved for further analysis. In addition, after flipping the microfluidic channel, stem cell differentiation from the EBs can be performed on an unconfined flat surface that is desired for various differentiation processes. In the experiments, murine embryonic stem cells (ES-D3) are cultured and formed EBs inside the developed device. The size of EBs is well controlled inside the device, and the neural differentiation is performed on the formed EBs after flipping the channel. The EB size-dependent stem cell differentiation is studied using the device to demonstrate its functions. The device provides a useful tool to study stem cell differentiation without complicated device fabrication and tedious cell handling under better-controlled microenvironments.
Compact surface plasma H− ion source with geometrical focusing
Authors: Dudnikov V. , Dudnikova G.
Published: September 2015

Factors limiting operating lifetime of a Compact Surface Plasma Sources (CSPS) are analyzed and possible treatments for lifetime enhancement are considered. Increased cooling permeate increased discharge power and increased beam intensity and duty factor. A design of an advanced CSPS with geometrical focusing of H− flux is presented.
Recent development of plasma optical systems (invited)
Authors: Goncharov A. A.
Published: September 2015

The article devotes a brief description of the recent development and current status of an ongoing research of plasma optical systems based on the fundamental plasma optical idea magnetic electron isolation, equipotentialization magnetic field lines, and the axi-symmetric cylindrical electrostatic plasma lens (PL) configuration. The experimental, theoretical, and simulation investigations have been carried out over recent years collaboratively between IP NASU (Kiev), LBNL (Berkeley, USA), and HCEI RAS (Tomsk). The crossed electric and magnetic fields inherent the PL configuration that provides the attractive method for establishing a stable plasma discharge at low pressure. Using PL configuration, several high reliability plasma devices were developed. These devices are attractive for many high-tech applications.
Interference with a quantum dot single-photon source and a laser at telecom wavelength
Authors: Felle M. , Huwer J. , Stevenson R. M. , Skiba-Szymanska J. , Ward M. B. , Farrer I. , Penty R. V. , Ritchie D. A. , Shields A. J.
Published: September 2015

The interference of photons emitted by dissimilar sources is an essential requirement for a wide range of photonic quantum information applications. Many of these applications are in quantum communications and need to operate at standard telecommunication wavelengths to minimize the impact of photon losses and be compatible with existing infrastructure. Here, we demonstrate for the first time the quantum interference of telecom-wavelength photons from an InAs/GaAs quantum dot single-photon source and a laser; an important step towards such applications. The results are in good agreement with a theoretical model, indicating a high degree of indistinguishability for the interfering photons.
Enhanced traveling wave amplification of co-planar slow wave structure by extended phase-matching
Authors: Palm Andrew , Sirigiri Jagadishwar , Shin Young-Min
Published: September 2015

The electron beam co-propagating with slow waves in a staggered double grating array (SDGA) efficiently amplifies millimeter and sub-millimeter waves over a wide spectrum. Our theoretical and numerical analyses show that the power amplification in the fundamental passband is enhanced by the extended beam-wave phase-matching. Particle-in-cell simulations on the SDGA slow wave structure, designed with 10.4 keV and 50–100 mA sheet beam, indicate that maintaining beam-wave synchronization along the entire length of the circuit improves the gain by 7.3% leading to a total gain of 28 dB, corresponding to 62 W saturated power at the middle of operating band, and a 3-dB bandwidth of 7 GHz with 10.5% at V-band (73.5 GHz center frequency) with saturated peak power reaching 80 W and 28 dB at 71 GHz. These results also show a reasonably good agreement with analytic calculations based on Pierce small signal gain theory.
Interplay between motility and cell-substratum adhesion in amoeboid cells
Authors: Zhu Xiaoying , Bouffanais Roland , Yue Dick K. P.
Published: September 2015

The effective migration of amoeboid cells requires a fine regulation of cell-substratum adhesion. These entwined processes have been shown to be regulated by a host of biophysical and biochemical cues. Here, we reveal the pivotal role played by calcium-based mechanosensation in the active regulation of adhesion resulting in a high migratory adaptability. Using mechanotactically driven Dictyostelium discoideum amoebae, we uncover the existence of optimal mechanosensitive conditions—corresponding to specific levels of extracellular calcium—for persistent directional migration over physicochemically different substrates. When these optimal mechanosensitive conditions are met, noticeable enhancement in cell migration directionality and speed is achieved, yet with significant differences among the different substrates. In the same narrow range of calcium concentrations that yields optimal cellular mechanosensory activity, we uncovered an absolute minimum in cell-substratum adhesion activity, for all considered substrates, with differences in adhesion strength among them amplified. The blocking of the mechanosensitive ion channels with gadolinium—i.e., the inhibition of the primary mechanosensory apparatus—hampers the active reduction in substrate adhesion, thereby leading to the same undifferentiated and drastically reduced directed migratory response. The adaptive behavioral responses of Dictyostelium cells sensitive to substrates with varying physicochemical properties suggest the possibility of novel surface analyses based on the mechanobiological ability of mechanosensitive and guidable cells to probe substrates at the nanometer-to-micrometer level.
Overview spectra and axial distribution of spectral line intensities in a high-current vacuum arc with CuCr electrodes
Authors: Lisnyak M. , Pipa A. V. , Gorchakov S. , Iseni S. , Franke St. , Khapour A. , Methling R. , Weltmann K.-D.
Published: September 2015

Spectroscopic investigations of free-burning vacuum arcs in diffuse mode with CuCr electrodes are presented. The experimental conditions of the investigated arc correspond to the typical system for vacuum circuit breakers. Spectra of six species Cu I, Cu II, Cu III, Cr I, Cr II, and Cr III have been analyzed in the wavelength range 350–810 nm. The axial intensity distributions were found to be strongly dependent on the ionization stage of radiating species. Emission distributions of Cr II and Cu II can be distinguished as well as the distributions of Cr III and Cu III. Information on the axial distribution was used to identify the spectra and for identification of overlapping spectral lines. The overview spectra and some spectral windows recorded with high resolution are presented. Analysis of axial distributions of emitted light, which originates from different ionization states, is presented and discussed.
The influence of electron energy quantization in a space-charge region on the accumulation capacitance of InAs metal-oxide-semiconductor capacitors
Authors: Kovchavtsev A. P. , Tsarenko A. V. , Guzev A. A. , Aksenov M. S. , Polovinkin V. G. , Nastovjak A. E. , Valisheva N. A.
Published: September 2015

The influence of electron energy quantization in a space-charge region on the accumulation capacitance of the InAs-based metal-oxide-semiconductor capacitors (MOSCAPs) has been investigated by modeling and comparison with the experimental data from Au/anodic layer(4-20 nm)/n-InAs(111)A MOSCAPs. The accumulation capacitance for MOSCAPs has been calculated by the solution of Poisson equation with different assumptions and the self-consistent solution of Schrödinger and Poisson equations with quantization taken into account. It was shown that the quantization during the MOSCAPs accumulation capacitance calculations should be taken into consideration for the correct interface states density determination by Terman method and the evaluation of gate dielectric thickness from capacitance-voltage measurements.
The effects of viscosity on the undulatory swimming dynamics of C. elegans
Authors: Backholm M. , Kasper A. K. S. , Schulman R. D. , Ryu W. S. , Dalnoki-Veress K.
Published: September 2015

The undulatory swimming dynamics of the millimetric nematode Caenorhabditis elegans was investigated in fluids with different viscosities. The technique of micropipette deflection was used to directly measure the drag forces experienced by the swimming worm in both the lateral and propulsive directions. Gait modulation due to increasing viscosity in our tethered system was found to be qualitatively similar to that of freely swimming worms. Resistive force theory was used to determine the drag coefficients of the slender swimmer, and the experimental values were compared to the classical theories of Lighthill as well as Gray and Hancock. The gait modulation was shown to be independent of how the environmental resistance is changed, indicating the relevance of only the fluid resistance on the swimming kinematics and dynamics of the nematode.
Perturbation theory for multicomponent fluids based on structural properties of hard-sphere chain mixtures
Authors: Hlushak Stepan
Published: September 2015

An analytical expression for the Laplace transform of the radial distribution function of a mixture of hard-sphere chains of arbitrary segment size and chain length is used to rigorously formulate the first-order Barker-Henderson perturbation theory for the contribution of the segment-segment dispersive interactions into thermodynamics of the Lennard-Jones chain mixtures. Based on this approximation, a simple variant of the statistical associating fluid theory is proposed and used to predict properties of several mixtures of chains of different lengths and segment sizes. The theory treats the dispersive interactions more rigorously than the conventional theories and provides means for more accurate description of dispersive interactions in the mixtures of highly asymmetric components.
Photodissociation spectroscopy of the dysprosium monochloride molecular ion
Authors: Dunning Alexander , Petrov Alexander , Schowalter Steven J. , Puri Prateek , Kotochigova Svetlana , Hudson Eric R.
Published: September 2015

We have performed a combined experimental and theoretical study of the photodissociation cross section of the molecular ion DyCl+. The photodissociation cross section for the photon energy range 35 500 cm−1 to 47 500 cm−1 is measured using an integrated ion trap and time-of-flight mass spectrometer; we observe a broad, asymmetric profile that is peaked near 43 000 cm−1. The theoretical cross section is determined from electronic potentials and transition dipole moments calculated using the relativistic configuration-interaction valence-bond and coupled-cluster methods. The electronic structure of DyCl+ is extremely complex due to the presence of multiple open electronic shells, including the 4f10 configuration. The molecule has nine attractive potentials with ionically bonded electrons and 99 repulsive potentials dissociating to a ground state Dy+ ion and Cl atom. We explain the lack of symmetry in the cross section as due to multiple contributions from one-electron-dominated transitions between the vibrational ground state and several resolved repulsive excited states.
The ageing and de-ageing behaviour of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 lead-free piezoelectric ceramics
Authors: Zhang Yichi , Glaum Julia , Ehmke Matthias C. , Bowman Keith J. , Blendell John E. , Hoffman Mark J.
Published: September 2015

Ageing behaviour usually occurs in acceptor-doped piezoelectric materials (e.g., hard lead zirconate titanate) and exhibits the development of a pinched or shifted hysteresis loop over time. Although no pinched hysteresis loop was observed for lead-free (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 material, this study showed that the piezoelectric properties change over time in the poled state. The shift of the hysteresis loop along the electric field axis and the development of asymmetry in strain and permittivity hysteresis loop were observed during the ageing process. The origin of this ageing behaviour is proposed to be local defect dipoles and the migration of the charged defects to the grain boundaries. The reorientation of the defect dipole contributes to a fast but unstable ageing mechanism in this material while the migration of the charged defects contributes to a slow but more stable mechanism.
Formation of polyhedral vesicles and polygonal membrane tubes induced by banana-shaped proteins
Authors: Noguchi Hiroshi
Published: September 2015

The shape transformations of fluid membranes induced by curved protein rods are studied using meshless membrane simulations. The rod assembly at low rod density induces a flat membrane tube and oblate vesicle. It is found that the polyhedral shapes are stabilized at high rod densities. The discrete shape transition between triangular and buckled discoidal tubes is obtained and their curvature energies are analyzed by a simple geometric model. For vesicles, triangular hosohedron and elliptic-disk shapes are formed in equilibrium, whereas tetrahedral and triangular prism shapes are obtained as metastable states.
An inspection of force reduction in high force electromagnetic tweezers made of FeCo-V foil by laser cutting
Authors: Chen La , Offenhäusser Andreas , Krause Hans-Joachim
Published: September 2015

One of the main goals in the design of magnetic tweezers is to obtain a high force output. In general, the force can be enhanced by adopting materials with high saturation magnetization and by using small sharp structures as magnetic pole tips. However, the practically achieved saturation forces are usually lower than predicted values. In this article, we inspect this issue in detail both by experiments and simulations. Our results show that the observed force reduction can be ascribed to two factors: magnetic performance deterioration near the cutting edges of the tips and a 3D geometrical effect. The high power laser used in cutting causes segregation and morphological roughness near the cutting edge. Moreover, the geometry of the magnetic tips plays an important role regarding the force behavior. As a matter of fact, there is a trade-off among high force, maneuverability, throughput, and manufacturing issues in practical design of magnetic tweezers.