bluuebunny/crossref_metadata_2025 huggingface dataset:
The calcineurin/NFAT pathway is activated in diagnostic breast cancer cases and is essential to survival and metastasis of mammary cancer cells
Authors: Tran Quang C , Leboucher S , Passaro D , Fuhrmann L , Nourieh M , Vincent-Salomon A , Ghysdael J
Published: February 2015

Nuclear factor of activated T cells 1 (NFAT1) expression has been associated with increased migratory/invasive properties of mammary tumor-derived cell lines in vitro. It is unknown, however, if NFAT activation actually occurs in breast cancer cases and whether the calcineurin/NFAT pathway is important to mammary tumorigenesis. Using a cohort of 321 diagnostic cases of the major subgroup of breast cancer, we found Cn/NFAT pathway activated in ER−PR−HER2− triple-negative breast cancer subtype, whereas its prevalence is less in other subgroups. Using a small hairpin RNA-based gene expression silencing approach in murine mammary tumor cell line (4T1), we show that not only NFAT1 but also NFAT2 and their upstream activator Cn are essential to the migratory and invasive properties of mammary tumor cells. We also demonstrate that Cn, NFAT1 and NFAT2 are essential to the tumorigenic and metastatic properties of these cells in mice, a phenotype which coincides with increased apoptosis in vivo. Finally, global gene expression analyses identified several NFAT-deregulated genes, many of them being previously associated with mammary tumorigenesis. In particular, we identified the gene encoding a disintegrin and metalloproteinase with thrombonspondin motifs 1, as being a potential direct target of NFAT1. Thus, our results show that the Cn/NFAT pathway is activated in diagnostic cases of breast cancers and is essential to the tumorigenic and metastatic potential of mammary tumor cell line. These results suggest that pharmacological inhibition of the Cn/NFAT pathway at different levels could be of therapeutical interest for breast cancer patients.
p53 is active in murine stem cells and alters the transcriptome in a manner that is reminiscent of mutant p53
Authors: Yan H , Solozobova V , Zhang P , Armant O , Kuehl B , Brenner-Weiss G , Blattner C
Published: February 2015

Since it was found that p53 is highly expressed in murine embryonic stem cells, it remained a mystery whether p53 is active in this cell type. We show that a significant part of p53 is localised in the nucleus of murine embryonic stem cells and that the majority of this nuclear p53 is bound to DNA. According to its nuclear localisation, we show that p53 alters the transcriptional program of stem cells. Nevertheless, the anti-proliferative activity of p53 is compromised in stem cells, and this control is due, at least in part, to the high amount of MdmX that is present in embryonic stem cells and bound to p53. Instead of the anti-proliferative activity that p53 has in differentiated cells, p53 controls transcription of pro-proliferative genes in embryonic stem cells including c-myc and c-jun. The impeded anti-proliferative activity of p53 and the induction of certain proto-oncogenes by p53 in murine embryonic stem cells can explain why stem cells proliferate efficiently despite having high levels of p53.
Structural basis for self-assembly of a cytolytic pore lined by protein and lipid
Authors: Tanaka Koji , Caaveiro Jose M.M. , Morante Koldo , González-Mañas Juan Manuel , Tsumoto Kouhei
Published: February 2015

Pore-forming toxins (PFT) are water-soluble proteins that possess the remarkable ability to self-assemble on the membrane of target cells, where they form pores causing cell damage. Here, we elucidate the mechanism of action of the haemolytic protein fragaceatoxin C (FraC), a α-barrel PFT, by determining the crystal structures of FraC at four different stages of the lytic mechanism, namely the water-soluble state, the monomeric lipid-bound form, an assembly intermediate and the fully assembled transmembrane pore. The structure of the transmembrane pore exhibits a unique architecture composed of both protein and lipids, with some of the lipids lining the pore wall, acting as assembly cofactors. The pore also exhibits lateral fenestrations that expose the hydrophobic core of the membrane to the aqueous environment. The incorporation of lipids from the target membrane within the structure of the pore provides a membrane-specific trigger for the activation of a haemolytic toxin.
Spin-current nano-oscillator based on nonlocal spin injection
Authors: Demidov V. E. , Urazhdin S. , Zholud A. , Sadovnikov A. V. , Slavin A. N. , Demokritov S. O.
Published: February 2015

Nonlocal spin injection has been recognized as an efficient mechanism for creation of pure spin currents not tied to the electrical charge transfer. Here we demonstrate experimentally that it can induce coherent magnetization dynamics, which can be utilized for the implementation of novel microwave nano-sources for spintronic and magnonic applications. We show that such sources exhibit a small oscillation linewidth and are tunable over a wide frequency range by the static magnetic field. Spatially resolved measurements of the dynamical magnetization indicate a relatively large oscillation area, resulting in a high stability of the oscillation with respect to thermal fluctuations. We propose a simple quasilinear dynamical model that reproduces well the oscillation characteristics.
Responses of Solid Tumor Cells in DMEM to Reactive Oxygen Species Generated by Non-Thermal Plasma and Chemically Induced ROS Systems
Authors: Kaushik Neha , Uddin Nizam , Sim Geon Bo , Hong Young June , Baik Ku Youn , Kim Chung Hyeok , Lee Su Jae , Kaushik Nagendra Kumar , Choi Eun Ha
Published: February 2015

In this study, we assessed the role of different reactive oxygen species (ROS) generated by soft jet plasma and chemical-induced ROS systems with regard to cell death in T98G, A549, HEK293 and MRC5 cell lines. For a comparison with plasma, we generated superoxide anion (O2−), hydroxyl radical (HO·) and hydrogen peroxide (H2O2) with chemicals inside an in vitro cell culture. Our data revealed that plasma decreased the viability and intracellular ATP values of cells and increased the apoptotic population via a caspase activation mechanism. Plasma altered the mitochondrial membrane potential and eventually up-regulated the mRNA expression levels of BAX, BAK1 and H2AX gene but simultaneously down-regulated the levels of Bcl-2 in solid tumor cells. Moreover, a western blot analysis confirmed that plasma also altered phosphorylated ERK1/2/MAPK protein levels. At the same time, using ROS scavengers with plasma, we observed that scavengers of HO· (mannitol) and H2O2 (catalase and sodium pyruvate) attenuated the activity of plasma on cells to a large extent. In contrast, radicals generated by specific chemical systems enhanced cell death drastically in cancer as well as normal cell lines in a dose-dependent fashion but not specific with regard to the cell type as compared to plasma.
SNORD76, a box C/D snoRNA, acts as a tumor suppressor in glioblastoma
Authors: Chen Luyue , Han Lei , Wei Jianwei , Zhang Kailiang , Shi Zhendong , Duan Ran , Li Shouwei , Zhou Xuan , Pu Peiyu , Zhang Jianning , Kang Chunsheng
Published: February 2015

Glioblastoma (GBM) is associated with disproportionately high morbidity and mortality, reflecting the need to develop new diagnostic and therapeutic targets for this disease. Recently, accumulating evidence has suggested that small nucleolar RNAs (snoRNAs) are gaining prominence and are more actively involved in tumorigenesis than previously thought. However, no report concerning the implication of snoRNAs in glioma has been published to date. In our study, SNORD76 was first found to be inversely associated with Hox Transcript Antisense Intergenic RNA (HOTAIR) knockdown and surprisingly, forcibly expressed SNORD76 inhibited proliferation and growth of glioma cells. Moreover, downregulation of SNORD76 led to a more malignant phenotype. The pleiotropy of SNORD76 overexpression could be achieved at least partially through inducing cell cycle arrest at S phase by affecting the Rb-associated cell cycle regulation. Enforced SNORD76 expression in orthotopic tumors resulted in decreased tumor growth and the reduction of tumor volume. Additionally, in surgically resected glioma tissues, SNORD76, not its host gene, was associated with the WHO classification and was selectively downregulated in GBM (WHO grade IV). Collectively, our study adds to a growing body of evidence for the participation of snoRNAs in gliomagenesis and is the first to implicate a snoRNA in glioblastoma.
Spouses and Depressive Symptoms in Older Adulthood
Authors: Pradeep Neeti , Sutin Angelina R.
Published: February 2015

Depressive symptoms may co-occur within couples and follow similar trajectories, but relatively little is known about this process in old age. This study thus examined the association between some spousal characteristics (spouse's depressive symptoms, age difference between spouses) and the trajectory of depressive symptoms in older adults. Participants ≥65 years old were drawn from the Health and Retirement Study (N = 12,010; Mean age = 70.60 and 69.16 for target husbands and wives, respectively). Depressive symptoms were measured with a short form of the Center for Epidemiological Studies Depression (CES-D) scale. Hierarchical Linear Modeling was used to model up to 9 assessments of depressive symptoms of target spouses (Mean number of CESD assessments per target spouse = 3, range 1–9). Depressive symptoms between spouses were correlated; convergence over time was modest. For both husbands and wives, having a younger spouse was associated with more depressive symptoms at age 65. These results suggest that there is concordance between spouses' depressive symptoms and that the age difference between spouses contribute to depressive symptoms as couples enter old age. The association between spouses' depressive symptoms is nearly as strong as the effect of each decade increase in age.
Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 piezoelectric materials
Authors: Maurya Deepam , Zhou Yuan , Wang Yaojin , Yan Yongke , Li Jiefang , Viehland Dwight , Priya Shashank
Published: February 2015

We synthesized grain-oriented lead-free piezoelectric materials in (K0.5Bi0.5TiO3-BaTiO3-xNa0.5Bi0.5TiO3 (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d33 ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials.
Combined node and link partitions method for finding overlapping communities in complex networks
Authors: Jin Di , Gabrys Bogdan , Dang Jianwu
Published: February 2015

Community detection in complex networks is a fundamental data analysis task in various domains and how to effectively find overlapping communities in real applications is still a challenge. In this work, we propose a new unified model and method for finding the best overlapping communities on the basis of the associated node and link partitions derived from the same framework. Specifically, we first describe a unified model that accommodates node and link communities (partitions) together and then present a nonnegative matrix factorization method to learn the parameters of the model. Thereafter, we infer the overlapping communities based on the derived node and link communities, i.e., determine each overlapped community between the corresponding node and link community with a greedy optimization of a local community function conductance. Finally, we introduce a model selection method based on consensus clustering to determine the number of communities. We have evaluated our method on both synthetic and real-world networks with ground-truths and compared it with seven state-of-the-art methods. The experimental results demonstrate the superior performance of our method over the competing ones in detecting overlapping communities for all analysed data sets. Improved performance is particularly pronounced in cases of more complicated networked community structures.
Flow-injection with enhanced evaporative light scattering detector detection and quantification of human serum albumin using gold nanoparticles
Authors: Wang Tao , Chen Mengbin , Niu Caixia , Liu Ning , Wang Le , Sun Binjie , Hua Wenhao , Ouyang Jin
Published: February 2015

The ELSD response for HSA was enhanced by using GNPs, making it possible to determine HSA by ELSD.
Highly efficient regioselective hydrosilylation of allenes using a [(3IP)Pd(allyl)]OTf catalyst; first example of allene hydrosilylation with phenyl- and diphenylsilane
Authors: Tafazolian Hosein , Schmidt Joseph A. R.
Published: February 2015

A [(3IP)Pd(allyl)]OTf complex was shown to have high activity and regioselectively for allene hydrosilylation employing a wide range of silanes.
Taking baby steps in molecular logic-based computation
Authors: Ling Jue , Daly Brian , Silverson Victoria A. D. , de Silva A. Prasanna
Published: February 2015

Constructs of fluorophores, receptors, spacers, 1O2 sensitizers, enzymes and oligonucleotides play their part in advancing the field of molecular logic-based computation.
pH-Assisted control over the binding and relocation of an acridine guest between a macrocyclic nanocarrier and natural DNA
Authors: Sayed Mhejabeen , Pal Haridas
Published: February 2015

Controlled binding and relocation of a dye–drug between a macrocyclic nanocarrier and natural DNA is demonstrated using pH as a stimulus.
Urban contamination sources reflected in inorganic pollution in urban lake deposits, Bergen, Norway
Authors: Andersson Malin , Eggen Ola Anfin
Published: February 2015

The 7000 years transition from a pristine environment towards a modern city has brought a number of chemical changes and effects to urban lake sediments in Bergen.
The temporal distribution, source and potential toxicity of polycyclic aromatic hydrocarbons in a sediment core from an urban lake in Wuhan, China
Authors: Lu Qian , Yang Zeyu , Wu Laiyan , Ruan Xinchao , Yang Wenwen
Published: February 2015

The temporal distribution, source and toxicity of PAHs and APAHs in a sediment core from an urban lake in Wuhan, were studied.
Ultra-strong coupling of molecular materials: spectroscopy and dynamics
Authors: George Jino , Wang Shaojun , Chervy Thibault , Canaguier-Durand Antoine , Schaeffer Gael , Lehn Jean-Marie , Hutchison James A. , Genet Cyriaque , Ebbesen Thomas W.
Published: February 2015

We report here a study of light–matter strong coupling involving three molecules with very different photo-physical properties. In particular we analyze their emission properties and show that the excitation spectra are very different from the static absorption of the coupled systems. Furthermore we report the emission quantum yields and excited state lifetimes, which are self-consistent. The above results raise a number of fundamental questions that are discussed and these demonstrate the need for further experiments and theoretical studies.
N-doped graphitic layer encased cobalt nanoparticles as efficient oxygen reduction catalysts in alkaline media
Authors: Han Ce , Bo Xiangjie , Zhang Yufan , Li Mian , Nsabimana Anaclet , Guo Liping
Published: February 2015

Nitrogen doped graphitic layer encased cobalt (N–C@Co) nanoparticle (N–C@Co) catalysts exhibited comparable catalytic performance, better stability and improved methanol tolerance towards ORR than those of the commercial Pt/C catalyst in alkaline media.
Environmentally benign antifouling potentials of triterpene-glycosides from Streptomyces fradiae: a mangrove isolate
Authors: Prakash Santhiyagu , Ramasubburayan Ramasamy , Iyapparaj Palanisamy , Ramaswamy Arthi Arikrishna Perumal , Ahila Natarajan Kumari , Ramkumar Vijayan Sri , Immanuel Grasian , Palavesam Arunachalam
Published: February 2015

In the present study, an attempt has been made to screen and evaluate the antifouling potentials of the actinobacterial strainStreptomyces fradiaeRMS-MSU isolated from the manakkudy mangroves of Tamilnadu.
Ti3+ self-doped Li4Ti5O12 nanosheets as anode materials for high performance lithium ion batteries
Authors: Nie Sen , Li Chunsong , Peng Hongrui , Li Guicun , Chen Kezheng
Published: February 2015

Ti3+ self-doped Li4Ti5O12 (S-LTO) nanosheets exhibit high specific capacity, excellent rate performance and outstanding cycling stability.
Gene regulation in Aspergillus oryzae promotes hyphal growth and flavor formation in soy sauce koji
Authors: Zhao Guozhong , Yao Yunping , Hao Guangfei , Fang Dongsheng , Yin Boxing , Cao Xiaohong , Chen Wei
Published: February 2015

Aspergillus oryzae100-8 and the parental strainA. oryzae3.042 are used in soy sauce fermentation in China.
Adsorption of fluoride on Mg/Fe layered double hydroxides material prepared via hydrothermal process
Authors: Wu Tao , Mao Lili , Wang Haizeng
Published: February 2015

A nitrate containing Mg/Fe-LDHs with ignorable leakage of metal ions and high fluoride adsorption capacity.
Repair efficiency of clustered abasic sites by APE1 in nucleosome core particles is sequence and position dependent
Authors: Singh Vandana , Kumari Bhavini , Das Prolay
Published: February 2015

DNA sequence context and nucleosomal positioning guide the repair efficiency of clustered abasic sites by APE1 enzyme.
Effect of the oxidation approach on carbon nanotube surface functional groups and electrooxidative filtration performance
Authors: Gao Guandao , Pan Meilan , Vecitis Chad D.
Published: February 2015

Does CNT electrooxidation affect its anode properties positively or negatively?
The fluorescence properties and aggregation behavior of tetraphenylethene–perylenebisimide dyads
Authors: Wang Yi Jia , Li Zeyu , Tong Jiaqi , Shen Xiao Yuan , Qin Anjun , Sun Jing Zhi , Tang Ben Zhong
Published: February 2015

Perylene-bisimides (PBIs) modified with tetraphenylethene (TPE) at N-terms show unique X-aggregation and are non-fluorescent in solution, aggregate and solid film due to the photoinduced charge transfer between TPE and PBI subunits.
Tailoring the surface charge of dextran-based polymer coated SPIONs for modulated stem cell uptake and MRI contrast
Authors: Barrow Michael , Taylor Arthur , Nieves Daniel J. , Bogart Lara K. , Mandal Pranab , Collins Christopher M. , Moore Lee R. , Chalmers Jeffrey J. , Lévy Raphaël , Williams Steve R. , Murray Patricia , Rosseinsky Matthew J. , Adams Dave J.
Published: February 2015

Tracking stem cells in vivo using non-invasive techniques is critical to evaluate their efficacy and safety.
A FRET based pH probe with a broad working range applicable to referenced ratiometric dual wavelength and luminescence lifetime read out
Authors: Meier Robert J. , Simbürger Johann M. B. , Soukka Tero , Schäferling Michael
Published: February 2015

A FRET system composed of a europium chelate and carboxynaphthofluorescein enables ratiometric pH sensing with an exceptionally broad dynamic range.
A red-shifted photochromic sulfonylurea for the remote control of pancreatic beta cell function
Authors: Broichhagen J. , Frank J. A. , Johnston N. R. , Mitchell R. K. , Šmid K. , Marchetti P. , Bugliani M. , Rutter G. A. , Trauner D. , Hodson D. J.
Published: February 2015

Heterocyclic azobenzene photoresponsive elements can be installed on sulfonylureas, yielding optical control over insulin release with yellow light.
Novel pnicogen bonding interactions with silylene as an electron donor: covalency, unusual substituent effects and new mechanisms
Authors: Zhuo Hongying , Li Qingzhong
Published: February 2015

A new pnicogen bonding involving silylene was proposed and characterized, exhibiting unexpected substituent effects and dependence on the pnicogen atom.
Rotationally resolved state-to-state photoionization and the photoelectron study of vanadium monocarbide and its cations (VC/VC+)
Authors: Chang Yih Chung , Luo Zhihong , Pan Yi , Zhang Zheng , Song Ying-Nan , Kuang Sophie Yajin , Yin Qing Zhu , Lau Kai-Chung , Ng C. Y.
Published: February 2015

Two-color VIS-UV laser pulsed filed ionization-photoelectron (PFI-PE) study and theoretical predictions for vanadium monocarbide (VC) neutral and its cation (VC+).
The microwave heating mechanism of N-(4-methoxybenzyliden)-4-butylaniline in liquid crystalline and isotropic phases as determined using in situ microwave irradiation NMR spectroscopy
Authors: Tasei Yugo , Tanigawa Fumikazu , Kawamura Izuru , Fujito Teruaki , Sato Motoyasu , Naito Akira
Published: February 2015

Non-equilibrium local heating states in the liquid crystal MBBA were observed using in situ microwave irradiation NMR spectroscopy.
A molecular dynamics study of model SI clathrate hydrates: the effect of guest size and guest–water interaction on decomposition kinetics
Authors: Das Subhadip , Baghel Vikesh Singh , Roy Sudip , Kumar Rajnish
Published: February 2015

One of the options suggested for methane recovery from natural gas hydrates is molecular replacement of methane by suitable guests like CO2 and N2.
Synthesis of cyclic polyesters: effects of alkoxy side chains in salicylaldiminato tin(ii) complexes
Authors: Wongmahasirikun Phonpimon , Prom-on Paweenuch , Sangtrirutnugul Preeyanuch , Kongsaeree Palangpon , Phomphrai Khamphee
Published: February 2015

A new salicylaldiminato tin(ii) catalyst system having alkoxy side chains has been developed and shown to effectively polymerize l-lactide and ε-caprolactone giving cyclic PLA and cyclic PCL, respectively.
Synthesis and thermal behavior of tin-based alloy (Sn–Ag–Cu) nanoparticles
Authors: Roshanghias Ali , Yakymovych Andriy , Bernardi Johannes , Ipser Herbert
Published: February 2015

Schematic model of the structural and morphological evolution of tin based SAC nanoparticles upon heating.
Visible light mediated sp3 C–H bond functionalization of N-aryl-1,2,3,4-tetrahydroisoquinolines via Ugi-type three-component reaction
Authors: Chen Yunyun , Feng Gaofeng
Published: February 2015

An efficient and high yield process for sp3 C–H bond functionalization of N-aryl-1,2,3,4-tetrahydroisoquinolines is disclosed.
Sodium periodate mediated oxidative transformations in organic synthesis
Authors: Sudalai Arumugam , Khenkin Alexander , Neumann Ronny
Published: February 2015

The investigation of new oxidative transformations for the synthesis of carbon–heteroatom and heteroatom–heteroatom bonds is of fundamental importance in the synthesis of numerous bioactive molecules and fine chemicals.
Editorial: Recognition and reactivity at interfaces
Authors: Scrimin Paolo
Published: February 2015

Showcasing a collection of cutting edge contributions on the topic of Recognition and Reactivity at Interfaces.
Thiacloprid suspension formula optimization by a response surface methodology
Authors: Li Bei-xing , Wang Wei-chang , Wang Kai , Zhang Da-xia , Guan Lei , Liu Feng
Published: February 2015

A response surface methodology with four factors at five levels was adopted to optimize a model thiacloprid suspension concentrate.
Zn interstitials and O vacancies responsible for n-type ZnO: what do the emission spectra reveal?
Authors: Bandopadhyay K. , Mitra J.
Published: February 2015

Evidencing interstitial Zn related defect states inside the conduction band of Zn-rich ZnO nanorods.
Green-emitting Lu3Al5O12:Ce3+ phosphor as a visible light amplifier for dye-sensitized solar cells
Authors: Han Gill Sang , Song Young Hyun , Kim Dong Hoe , Lee Min-Ji , Lee Dong Geon , Han Se-Hoon , Kim Yongjoo , Jung Mong-Kwon , Yoon Dae-Ho , Jung Hyun Suk
Published: February 2015

A down convertor Lu3Al5O12:Ce3+ (LuAG) phosphor was used as a visible light amplifier for dye-sensitized solar cells (DSSCs).
Facile synthesis of porous coin-like iron and its excellent electromagnetic absorption performance
Authors: Lv Hualiang , Liang Xiaohui , Cheng Yan , Ji Guangbin , Tang Dongming , Zhang Baoshan , Zhang Haiqian , Du Youwei
Published: February 2015

The porous coin-like iron exhibits excellent microwave absorption properties with the optimal reflection loss value of −53.2 dB at a thickness of 1.4 mm. This special structure is attributed to electromagnetic scattering behavior which is benefit for microwave absorption.
A dansyl-based fluorescent probe for selectively detecting Cu2+and imaging in living cells
Authors: Cao Meijiao , Jiang Lina , Hu Fang , Zhang Yufeng , Yang Wen Chao , Liu Sheng Hua , Yin Jun
Published: February 2015

Copper is a crucial transition metal ion that plays an essential role in environmental, biological, and chemical systems.
Sequential one-pot approach for the synthesis of functionalized phthalans via Heck-reduction–cyclization (HRC) reactions
Authors: Krishna Jonnada , Niharika Pedireddi , Satyanarayana Gedu
Published: February 2015

An efficient and practical method is described for the direct synthesis of 1,3-dihydroisobenzofurans, an important structural motif present in biologically active natural or synthetic compounds.
Promotion mechanism of CeO2addition on the low temperature SCR reaction over MnOx/TiO2: a new insight from the kinetic study
Authors: Xiong Shangchao , Liao Yong , Dang Hao , Qi Feihong , Yang Shijian
Published: February 2015

A new insight into CeO2addition on the SCR reaction over MnOx/TiO2was drawn according to steady-state kinetic analysis.
Tandem catalytic conversion of 1-butene and ethene to propene over combined mesoporous W-FDU-12 and MgO catalysts
Authors: Xu Wei , Lin Chao , Liu Huan , Yu Hongbo , Tao Kai , Zhou Shenghu
Published: February 2015

W substituted mesoporous FDU-12 combined with MgO showed enhanced catalytic performance for tandem conversion of 1-butene and ethene to propene.
Electrodeposited Bi-Au nanocomposite modified carbon paste electrode for the simultaneous determination of copper and mercury
Authors: Sahoo S. , Satpati A. K. , Reddy A. V. R.
Published: February 2015

An analytical anodic stripping voltammetry method has been developed for the simultaneous determination of copper and mercury at ultratrace levels using the Bi–AuNP modified CPE.
Bis(dipyrrinato)metal(ii) coordination polymers: crystallization, exfoliation into single wires, and electric conversion ability
Authors: Matsuoka Ryota , Toyoda Ryojun , Sakamoto Ryota , Tsuchiya Mizuho , Hoshiko Ken , Nagayama Tatsuhiro , Nonoguchi Yoshiyuki , Sugimoto Kunihisa , Nishibori Eiji , Kawai Tsuyoshi , Nishihara Hiroshi
Published: February 2015

The titled coordination polymers feature crystallization, single wire exfoliation, processability, and applicability to photoelectric and thermoelectric conversion systems.
Glassy dynamics of poly(2-vinyl-pyridine) brushes with varying grafting density
Authors: Neubauer Nils , Winkler René , Tress Martin , Uhlmann Petra , Reiche Martin , Kipnusu Wycliffe Kiprop , Kremer Friedrich
Published: February 2015

By using Broadband Dielectric Spectroscopy with nanostructured silicon electrodes we found that the segmental dynamics (dynamic glass transition) of a series of P2VP brushes is bulk-like.
Correction: Flexible and highly stable electrospun nanofibrous membrane incorporating gold nanoclusters as an efficient probe for visual colorimetric detection of Hg(ii)
Authors: Senthamizhan Anitha , Celebioglu Asli , Uyar Tamer
Published: February 2015

Correction for ‘Flexible and highly stable electrospun nanofibrous membrane incorporating gold nanoclusters as an efficient probe for visual colorimetric detection of Hg(ii)’ by Anitha Senthamizhan et al., J. Mater. Chem. A, 2014, 2, 12717–12723.
Achievable rate regions for many‐to‐one Gaussian interference channel with a fusion centre
Authors: Baianifar Mahdi , Behroozi Hamid
Published: February 2015

This paper considers a many‐to‐one Gaussian interference channel with a fusion centre (FC) where there is a K ‐user interference channel in which only one relay (receiver) faces interference while the remaining K‐1 receivers are interference free. All the relays communicate information about their observed sequence to the FC through noiseless links at communication rate R0. First, by analysing traditional relaying schemes, i.e., Decode and Forward, Compress and Forward and Compute and Forward, three rate‐regions for this setting are derived. Then, based on nested lattice codes, a new achievable rate‐region is provided. Based on the proposed scheme, one can design a transmission scheme that can recover both integer and non‐integer linear combination of messages. Numerical examples show that if channel gains are integer, the proposed scheme performs similarly to the compute‐and‐forward scheme. In the case of non‐integer channel gains, the proposed scheme outperforms other relaying schemes at high signal‐to‐noise ratios. Finally, it is shown that if the channel gains are larger than one and if the rate of each relay‐to‐FC link equals to the capacity of an AWGN channel, then the proposed scheme can achieve the capacity region in high SNR regime.
Annulus Fibrosus Can Strip Hyaline Cartilage End Plate from Subchondral Bone: A Study of the Intervertebral Disk in Tension
Authors: Balkovec Christian , Adams Michael A. , Dolan Patricia , McGill Stuart M.
Published: February 2015

Study Design

Biomechanical study on cadaveric spines.

Objective

Spinal bending causes the annulus to pull vertically (axially) on the end plate, but failure mechanisms in response to this type of loading are poorly understood. Therefore, the objective of this study was to identify the weak point of the intervertebral disk in tension.

Methods

Cadaveric motion segments (aged 79 to 88 years) were dissected to create midsagittal blocks of tissue, with ∼10 mm of bone superior and inferior to the disk. From these blocks, 14 bone–disk–bone slices (average 4.8 mm thick) were cut in the frontal plane. Each slice was gripped by its bony ends and stretched to failure at 1 mm/s. Mode of failure was recorded using a digital camera.

Results

Of the 14 slices, 10 failed by the hyaline cartilage being peeled off the subchondral bone, with the failure starting opposite the lateral annulus and proceeding medially. Two slices failed by rupturing of the trabecular bone, and a further two failed in the annulus.

Conclusions

The hyaline cartilage–bone junction is the disk's weak link in tension. These findings provide a plausible mechanism for the appearance of bone and cartilage fragments in herniated material. Stripping cartilage from the bony end plate would result in the herniated mass containing relatively stiff cartilage that does not easily resorb.
Surface hopping with a manifold of electronic states. I. Incorporating surface-leaking to capture lifetimes
Authors: Ouyang Wenjun , Dou Wenjie , Subotnik Joseph E.
Published: February 2015

We investigate the incorporation of the surface-leaking (SL) algorithm into Tully’s fewest-switches surface hopping (FSSH) algorithm to simulate some electronic relaxation induced by an electronic bath in conjunction with some electronic transitions between discrete states. The resulting SL-FSSH algorithm is benchmarked against exact quantum scattering calculations for three one-dimensional model problems. The results show excellent agreement between SL-FSSH and exact quantum dynamics in the wide band limit, suggesting the potential for a SL-FSSH algorithm. Discrepancies and failures are investigated in detail to understand the factors that will limit the reliability of SL-FSSH, especially the wide band approximation. Considering the easiness of implementation and the low computational cost, we expect this method to be useful in studying processes involving both a continuum of electronic states (where electronic dynamics are probabilistic) and processes involving only a few electronic states (where non-adiabatic processes cannot ignore short-time coherence).
Surface hopping with a manifold of electronic states. II. Application to the many-body Anderson-Holstein model
Authors: Dou Wenjie , Nitzan Abraham , Subotnik Joseph E.
Published: February 2015

We investigate a simple surface hopping (SH) approach for modeling a single impurity level coupled to a single phonon and an electronic (metal) bath (i.e., the Anderson-Holstein model). The phonon degree of freedom is treated classically with motion along–and hops between–diabatic potential energy surfaces. The hopping rate is determined by the dynamics of the electronic bath (which are treated implicitly). For the case of one electronic bath, in the limit of small coupling to the bath, SH recovers phonon relaxation to thermal equilibrium and yields the correct impurity electron population (as compared with numerical renormalization group). For the case of out of equilibrium dynamics, SH current-voltage (I-V) curve is compared with the quantum master equation (QME) over a range of parameters, spanning the quantum region to the classical region. In the limit of large temperature, SH and QME agree. Furthermore, we can show that, in the limit of low temperature, the QME agrees with real-time path integral calculations. As such, the simple procedure described here should be useful in many other contexts.
Gas diffusion electrode setup for catalyst testing in concentrated phosphoric acid at elevated temperatures
Authors: Wiberg Gustav K. H. , Fleige Michael , Arenz Matthias
Published: February 2015

We present a detailed description of the construction and testing of an electrochemical cell setup allowing the investigation of a gas diffusion electrode containing carbon supported high surface area catalysts. The setup is designed for measurements in concentrated phosphoric acid at elevated temperature, i.e., very close to the actual conditions in high temperature proton exchange membrane fuel cells (HT-PEMFCs). The cell consists of a stainless steel flow field and a PEEK plastic cell body comprising the electrochemical cell, which exhibits a three electrode configuration. The cell body and flow field are braced using a KF-25 vacuum flange clamp, which allows an easy assembly of the setup. As demonstrated, the setup can be used to investigate temperature dependent electrochemical processes on high surface area type electrocatalysts, but it also enables quick screening tests of HT-PEMFC catalysts under realistic conditions.
A high-resolution XAS study of aqueous Cu(II) in liquid and frozen solutions: Pyramidal, polymorphic, and non-centrosymmetric
Authors: Frank Patrick , Benfatto Maurizio , Qayyam Munzarin , Hedman Britt , Hodgson Keith O.
Published: February 2015

High-resolution EXAFS (k = 18 Å−1) and MXAN XAS analyses show that axially elongated square pyramidal [Cu(H2O)5]2+ dominates the structure of Cu(II) in aqueous solution, rather than 6-coordinate JT-octahedral [Cu(H2O)6]2+. Freezing produced a shoulder at 8989.6 eV on the rising XAS edge and an altered EXAFS spectrum, while 1s → 3d transitions remained invariant in energy position and intensity. Core square pyramidal [Cu(H2O)5]2+ also dominates frozen solution. Solvation shells were found at ∼3.6 Å (EXAFS) or ∼3.8 Å (MXAN) in both liquid and frozen phases. However, MXAN analysis revealed that about half the time in liquid solution, [Cu(H2O)5]2+ associates with an axially non-bonding 2.9 Å water molecule. This distant water apparently organizes the solvation shell. When the 2.9 Å water molecule is absent, the second shell is undetectable to MXAN. The two structural arrangements may represent energetic minima of fluxional dissolved aqueous [Cu(H2O)5]2+. The 2.9 Å trans-axial water resolves an apparent conflict of the [Cu(H2O)5]2+ core model with a dissociational exchange mechanism. In frozen solution, [Cu(H2O)5]2+ is associated with either a 3.0 Å axial non-bonded water molecule or an axial ClO4− at 3.2 Å. Both structures are again of approximately equal presence. When the axial ClO4− is present, Cu(II) is ∼0.5 Å above the mean O4 plane. This study establishes [Cu(H2O)5]2+ as the dominant core structure for Cu(II) in water solution, and is the first to both empirically resolve multiple extended solution structures for fluxional [Cu(H2O)5]2+ and to provide direct evidence for second shell dynamics.
Hydrodynamic interactions of two nearly touching Brownian spheres in a stiff potential: Effect of fluid inertia
Authors: Radiom Milad , Robbins Brian , Paul Mark , Ducker William
Published: February 2015

The hydrodynamic interaction of two closely spaced micron-scale spheres undergoing Brownian motion was measured as a function of their separation. Each sphere was attached to the distal end of a different atomic force microscopy cantilever, placing each sphere in a stiff one-dimensional potential (0.08 Nm−1) with a high frequency of thermal oscillations (resonance at 4 kHz). As a result, the sphere’s inertial and restoring forces were significant when compared to the force due to viscous drag. We explored interparticle gap regions where there was overlap between the two Stokes layers surrounding each sphere. Our experimental measurements are the first of their kind in this parameter regime. The high frequency of oscillation of the spheres means that an analysis of the fluid dynamics would include the effects of fluid inertia, as described by the unsteady Stokes equation. However, we find that, for interparticle separations less than twice the thickness of the wake of the unsteady viscous boundary layer (the Stokes layer), the hydrodynamic interaction between the Brownian particles is well-approximated by analytical expressions that neglect the inertia of the fluid. This is because elevated frictional forces at narrow gaps dominate fluid inertial effects. The significance is that interparticle collisions and concentrated suspensions at this condition can be modeled without the need to incorporate fluid inertia. We suggest a way to predict when fluid inertial effects can be ignored by including the gap-width dependence into the frequency number. We also show that low frequency number analysis can be used to determine the microrheology of mixtures at interfaces.
Electro-phoretic rotation and orientation of polarizable spheroidal particles in AC fields
Authors: Miloh Touvia , Goldstein Ben Weis
Published: February 2015

A theoretical study is provided for determining the angular rotation rate of an ideally polarized (metallic) spheroidal particle freely suspended in a symmetric electrolyte under general alternating current ambient electric excitations. In particular, we discuss cases of electro-rotation (ROT) and electro-orientation (EOR) of such nano/micro particles incited by two orthogonal electric field components which may be out of phase. The analysis is carried under the Poisson-Nernst-Planck approximation and the “weak” field model. The analytic expressions thus obtained are valid for a conducting prolate spheroid with arbitrary eccentricity including the limiting cases of isotropic spheres and infinitely long cylindrical rods. The total dipolophoretic (DIP) angular velocity is decomposed from contributions due to dielectrophoresis (DEP) induced by the dipole-moment within the particle and by the induced-charge electrophoresis (ICEP) mechanism near the conducting surface. It is demonstrated that the explicit expressions for the DIP angular velocities reduce to the well-known ROT solution for the sphere as well as to the recently found expressions (based on slender-body approximation) for both ROT and EOR of metal nanowires [Arcenegui et al., “Electro-orientation and electrorotation of metal nanowires,” Phys. Rev. E 88(6), 063018 (2013)]. Some comparisons with available experimental data are also provided for slender spheroidal geometries including a detailed discussion of DEP and ICEP effects and their relative contributions to the overall DIP rotational velocity.
Charge-displacement analysis via natural orbitals for chemical valence: Charge transfer effects in coordination chemistry
Authors: Bistoni Giovanni , Rampino Sergio , Tarantelli Francesco , Belpassi Leonardo
Published: February 2015

We recently devised a simple scheme for analyzing on quantitative grounds the Dewar-Chatt-Duncanson donation and back-donation in symmetric coordination complexes. Our approach is based on a symmetry decomposition of the so called Charge-Displacement (CD) function quantifying the charge flow, upon formation of a metal (M)-substrate (S) bond, along the M–S interaction axis and provides clear-cut measures of donation and back-donation charges in correlation with experimental observables [G. Bistoni et al., Angew. Chem., Int. Ed. 52, 11599 (2013)]. The symmetry constraints exclude of course from the analysis most systems of interest in coordination chemistry. In this paper, we show how to entirely overcome this limitation by taking advantage of the properties of the natural orbitals for chemical valence [M. Mitoraj and A. Michalak, J. Mol. Model. 13, 347 (2007)]. A general scheme for disentangling donation and back-donation in the CD function of both symmetric and non-symmetric systems is presented and illustrated through applications to M–ethyne (M = Au, Ni and W) coordination bonds, including an explicative study on substrate activation in a model reaction mechanism.
Use of density functional theory method to calculate structures of neutral carbon clusters Cn (3 ≤ n ≤ 24) and study their variability of structural forms
Authors: Yen T. W. , Lai S. K.
Published: February 2015

In this work, we present modifications to the well-known basin hopping (BH) optimization algorithm [D. J. Wales and J. P. Doye, J. Phys. Chem. A 101, 5111 (1997)] by incorporating in it the unique and specific nature of interactions among valence electrons and ions in carbon atoms through calculating the cluster’s total energy by the density functional tight-binding (DFTB) theory, using it to find the lowest energy structures of carbon clusters and, from these optimized atomic and electronic structures, studying their varied forms of topological transitions, which include a linear chain, a monocyclic to a polycyclic ring, and a fullerene/cage-like geometry. In this modified BH (MBH) algorithm, we define a spatial volume within which the cluster’s lowest energy structure is to be searched, and introduce in addition a cut-and-splice genetic operator to increase the searching performance of the energy minimum than the original BH technique. The present MBH/DFTB algorithm is, therefore, characteristically distinguishable from the original BH technique commonly applied to nonmetallic and metallic clusters, technically more thorough and natural in describing the intricate couplings between valence electrons and ions in a carbon cluster, and thus theoretically sound in putting these two charged components on an equal footing. The proposed modified minimization algorithm should be more appropriate, accurate, and precise in the description of a carbon cluster. We evaluate the present algorithm, its energy-minimum searching in particular, by its optimization robustness. Specifically, we first check the MBH/DFTB technique for two representative carbon clusters of larger size, i.e., C60 and C72 against the popular cut-and-splice approach [D. M. Deaven and K. M. Ho, Phys. Rev. Lett. 75, 288 (1995)] that normally is combined with the genetic algorithm method for finding the cluster’s energy minimum, before employing it to investigate carbon clusters in the size range C3-C24 studying their topological transitions. An effort was also made to compare our MBH/DFTB and its re-optimized results carried out by full density functional theory (DFT) calculations with some early DFT-based studies.
Tunneling splittings in formic acid dimer: An adiabatic approximation to the Herring formula
Authors: Jain Amber , Sibert Edwin L.
Published: February 2015

Small symmetric molecules and low-dimensional model Hamiltonians are excellent systems for benchmarking theories to compute tunneling splittings. In this work, we investigate a three dimensional model Hamiltonian coupled to a harmonic bath that describes concerted proton transfer in the formic acid dimer. The three modes include the symmetric proton stretch, the symmetric dimer rock, and the dimer stretch. These modes provide a paradigm for the symmetric and anti-symmetric coupled tunneling pathways, these being recognized in the literature as two of the more important classes of coupling. The effects of selective vibrational excitation and coupling to a bath on the tunneling splittings are presented. The splittings for highly excited states are computed using a novel method that makes an adiabatic approximation to the Herring estimate. Results, which are in excellent agreement with the exact splittings, are compared with those obtained using the Makri-Miller approach. This latter method has been shown to provide quality results for tunneling splittings including highly excited vibrational states.
Unusual behavior in magnesium-copper cluster matter produced by helium droplet mediated deposition
Authors: Emery S. B. , Xin Y. , Ridge C. J. , Buszek R. J. , Boatz J. A. , Boyle J. M. , Little B. K. , Lindsay C. M.
Published: February 2015

We demonstrate the ability to produce core-shell nanoclusters of materials that typically undergo intermetallic reactions using helium droplet mediated deposition. Composite structures of magnesium and copper were produced by sequential condensation of metal vapors inside the 0.4 K helium droplet baths and then gently deposited onto a substrate for analysis. Upon deposition, the individual clusters, with diameters ∼5 nm, form a cluster material which was subsequently characterized using scanning and transmission electron microscopies. Results of this analysis reveal the following about the deposited cluster material: it is in the un-alloyed chemical state, it maintains a stable core-shell 5 nm structure at sub-monolayer quantities, and it aggregates into unreacted structures of ∼75 nm during further deposition. Surprisingly, high angle annular dark field scanning transmission electron microscopy images revealed that the copper appears to displace the magnesium at the core of the composite cluster despite magnesium being the initially condensed species within the droplet. This phenomenon was studied further using preliminary density functional theory which revealed that copper atoms, when added sequentially to magnesium clusters, penetrate into the magnesium cores.
Lithographically defined few-electron silicon quantum dots based on a silicon-on-insulator substrate
Authors: Horibe Kosuke , Kodera Tetsuo , Oda Shunri
Published: February 2015

Silicon quantum dot (QD) devices with a proximal single-electron transistor (SET) charge sensor have been fabricated in a metal-oxide-semiconductor structure based on a silicon-on-insulator substrate. The charge state of the QDs was clearly read out using the charge sensor via the SET current. The lithographically defined small QDs enabled clear observation of the few-electron regime of a single QD and a double QD by charge sensing. Tunnel coupling on tunnel barriers of the QDs can be controlled by tuning the top-gate voltages, which can be used for manipulation of the spin quantum bit via exchange interaction between tunnel-coupled QDs. The lithographically defined silicon QD device reported here is technologically simple and does not require electrical gates to create QD confinement potentials, which is advantageous for the integration of complicated constructs such as multiple QD structures with SET charge sensors for the purpose of spin-based quantum computing.