bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrafast visualization of crystallization and grain growth in shock-compressed SiO2
Authors: Gleason A. E. , Bolme C. A. , Lee H. J. , Nagler B. , Galtier E. , Milathianaki D. , Hawreliak J. , Kraus R. G. , Eggert J. H. , Fratanduono D. E. , Collins G. W. , Sandberg R. , Yang W. , Mao W. L.
Published: September 2015

Pressure- and temperature-induced phase transitions have been studied for more than a century but very little is known about the non-equilibrium processes by which the atoms rearrange. Shock compression generates a nearly instantaneous propagating high-pressure/temperature condition while in situ X-ray diffraction (XRD) probes the time-dependent atomic arrangement. Here we present in situ pump–probe XRD measurements on shock-compressed fused silica, revealing an amorphous to crystalline high-pressure stishovite phase transition. Using the size broadening of the diffraction peaks, the growth of nanocrystalline stishovite grains is resolved on the nanosecond timescale just after shock compression. At applied pressures above 18 GPa the nuclueation of stishovite appears to be kinetically limited to 1.4±0.4 ns. The functional form of this grain growth suggests homogeneous nucleation and attachment as the growth mechanism. These are the first observations of crystalline grain growth in the shock front between low- and high-pressure states via XRD.
Nanoscale imaging of buried topological defects with quantitative X-ray magnetic microscopy
Authors: Blanco-Roldán C. , Quirós C. , Sorrentino A. , Hierro-Rodríguez A. , Álvarez-Prado L. M. , Valcárcel R. , Duch M. , Torras N. , Esteve J. , Martín J. I. , Vélez M. , Alameda J. M. , Pereiro E. , Ferrer S.
Published: September 2015

Advances in nanoscale magnetism increasingly require characterization tools providing detailed descriptions of magnetic configurations. Magnetic transmission X-ray microscopy produces element specific magnetic domain images with nanometric lateral resolution in films up to ∼100 nm thick. Here we present an imaging method using the angular dependence of magnetic contrast in a series of high resolution transmission X-ray microscopy images to obtain quantitative descriptions of the magnetization (canting angles relative to surface normal and sense). This method is applied to 55–120 nm thick ferromagnetic NdCo5 layers (canting angles between 65° and 22°), and to a NdCo5 film covered with permalloy. Interestingly, permalloy induces a 43° rotation of Co magnetization towards surface normal. Our method allows identifying complex topological defects (merons or ½ skyrmions) in a NdCo5 film that are only partially replicated by the permalloy overlayer. These results open possibilities for the characterization of deeply buried magnetic topological defects, nanostructures and devices.
An 80 kyr-long continuous speleothem record from Dim Cave, SW Turkey with paleoclimatic implications for the Eastern Mediterranean
Authors: Ünal-İmer Ezgi , Shulmeister James , Zhao Jian-Xin , Tonguç Uysal I. , Feng Yue-Xing , Duc Nguyen Ai , Yüce Galip
Published: September 2015

Speleothem-based stable isotope records are valuable in sub-humid and semi-arid settings where many other terrestrial climate proxies are fragmentary. The Eastern Mediterranean is one such region. Here we present an 80-kyr-long precisely-dated (by U-series) and high-resolution oxygen (δ18O) and carbon (δ13C) records from Dim Cave (~36°N) in SW Turkey. The glacial-interglacial δ18O variations in the Dim Cave speleothem are best explained in terms of changes in the trajectories of winter westerly air masses. These are along a northerly (European) track (isotopically less depleted) during the early last glaciation but are gradually depressed southward closer to the modern westerly track along the North African coast (more depleted) after c.50 kyr and remain in the southern track through the Last Glacial Maximum. The southward displacement of the westerly track reflects growth of the Fennoscandian ice sheet and its impact on westerly wind fields. Changes in δ13C are interpreted as reflecting soil organic matter composition and/or thickness. δ13C values are significantly more negative in interglacials reflecting active carbonic acid production in the soil and less negative in glacial times reflecting carbonate rock values. Several Heinrich events are recorded in the Dim record indicating intensification of westerly flow across this part of the EM.
Binding interface between the Salmonella σS/RpoS subunit of RNA polymerase and Crl: hints from bacterial species lacking crl
Authors: Cavaliere Paola , Sizun Christina , Levi-Acobas Fabienne , Nowakowski Mireille , Monteil Véronique , Bontems François , Bellalou Jacques , Mayer Claudine , Norel Françoise
Published: September 2015

In many Gram-negative bacteria, including Salmonella enterica serovar Typhimurium (S. Typhimurium), the sigma factor RpoS/σS accumulates during stationary phase of growth and associates with the core RNA polymerase enzyme (E) to promote transcription initiation of genes involved in general stress resistance and starvation survival. Whereas σ factors are usually inactivated upon interaction with anti-σ proteins, σS binding to the Crl protein increases σS activity by favouring its association to E. Taking advantage of evolution of the σS sequence in bacterial species that do not contain a crl gene, like Pseudomonas aeruginosa, we identified and assigned a critical arginine residue in σS to the S. Typhimurium σS-Crl binding interface. We solved the solution structure of S. Typhimurium Crl by NMR and used it for NMR binding assays with σS and to generate in silico models of the σS-Crl complex constrained by mutational analysis. The σS-Crl models suggest that the identified arginine in σS interacts with an aspartate of Crl that is required for σS binding and is located inside a cavity enclosed by flexible loops, which also contribute to the interface. This study provides the basis for further structural investigation of the σS-Crl complex.
Amlexanox Suppresses Osteoclastogenesis and Prevents Ovariectomy-Induced Bone Loss
Authors: Zhang Yong , Guan Hanfeng , Li Jing , Fang Zhong , Chen Wenjian , Li Feng
Published: September 2015

The activity of protein kinases IKK-ε and TANK-binding kinase 1 (TBK1) has been shown to be associated with inflammatory diseases. As an inhibitor of IKK-ε and TBK1, amlexanox is an anti-inflammatory, anti-allergic, immunomodulator and used for treatment of ulcer, allergic rhinitis and asthma in clinic. We hypothesized that amlexanox may be used for treatment of osteoclast-related diseases which frequently associated with a low grade of systemic inflammation. In this study, we investigated the effects of amlexanox on RANKL-induced osteoclastogenesis in vitro and ovariectomy-mediated bone loss in vivo. In primary bone marrow derived macrophages (BMMs), amlexanox inhibited osteoclast formation and bone resorption. At the molecular level, amlexanox suppressed RANKL-induced activation of nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPKs), c-Fos and NFATc1. Amlexanox decreased the expression of osteoclast-specific genes, including TRAP, MMP9, Cathepsin K and NFATc1. Moreover, amlexanox enhanced osteoblast differentiation of BMSCs. In ovariectomized (OVX) mouse model, amlexanox prevented OVX-induced bone loss by suppressing osteoclast activity. Taken together, our results demonstrate that amlexanox suppresses osteoclastogenesis and prevents OVX-induced bone loss. Therefore, amlexanox may be considered as a new therapeutic candidate for osteoclast-related diseases, such as osteoporosis and rheumatoid arthritis.
Low-Energy Electron Potentiometry: Contactless Imaging of Charge Transport on the Nanoscale
Authors: Kautz J. , Jobst J. , Sorger C. , Tromp R. M. , Weber H. B. , van der Molen S. J.
Published: September 2015

Charge transport measurements form an essential tool in condensed matter physics. The usual approach is to contact a sample by two or four probes, measure the resistance and derive the resistivity, assuming homogeneity within the sample. A more thorough understanding, however, requires knowledge of local resistivity variations. Spatially resolved information is particularly important when studying novel materials like topological insulators, where the current is localized at the edges, or quasi-two-dimensional (2D) systems, where small-scale variations can determine global properties. Here, we demonstrate a new method to determine spatially-resolved voltage maps of current-carrying samples. This technique is based on low-energy electron microscopy (LEEM) and is therefore quick and non-invasive. It makes use of resonance-induced contrast, which strongly depends on the local potential. We demonstrate our method using single to triple layer graphene. However, it is straightforwardly extendable to other quasi-2D systems, most prominently to the upcoming class of layered van der Waals materials.
Whole-genome Sequencing for Tracing the Transmission Link between Two ARD Outbreaks Caused by a Novel HAdV Serotype 7 Variant, China
Authors: Qiu Shaofu , Li Peng , Liu Hongbo , Wang Yong , Liu Nan , Li Chengyi , Li Shenlong , Li Ming , Jiang Zhengjie , Sun Huandong , Li Ying , Xie Jing , Yang Chaojie , Wang Jian , Li Hao , Yi Shengjie , Wu Zhihao , Jia Leili , Wang Ligui , Hao Rongzhang , Sun Yansong , Huang Liuyu , Ma Hui , Yuan Zhengquan , Song Hongbin
Published: September 2015

From December 2012 to February 2013, two outbreaks of acute respiratory disease caused by HAdV-7 were reported in China. We investigated possible transmission links between these two seemingly unrelated outbreaks by integration of epidemiological and whole-genome sequencing (WGS) data. WGS analyses showed that the HAdV-7 isolates from the two outbreaks were genetically indistinguishable; however, a 12 bp deletion in the virus-associated RNA gene distinguished the outbreak isolates from other HAdV-7 isolates. Outbreak HAdV-7 isolates demonstrated increased viral replication compared to non-outbreak associated HAdV-7 isolate. Epidemiological data supported that the first outbreak was caused by introduction of the novel HAdV-7 virus by an infected recruit upon arrival at the training base. Nosocomial transmission by close contacts was the most likely source leading to onset of the second HAdV-7 outbreak, establishing the apparent transmission link between the outbreaks. Our findings imply that in-hospital contact investigations should be encouraged to reduce or interrupt further spread of infectious agents when treating outbreak cases and WGS can provide useful information guiding infection-control interventions.
Photoluminescence studies of a perceived white light emission from a monolithic InGaN/GaN quantum well structure
Authors: Ben Sedrine N. , Esteves T. C. , Rodrigues J. , Rino L. , Correia M. R. , Sequeira M. C. , Neves A. J. , Alves E. , Bockowski M. , Edwards P. R. , O’Donnell K. P. , Lorenz K. , Monteiro T.
Published: September 2015

In this work we demonstrate by photoluminescence studies white light emission from a monolithic InGaN/GaN single quantum well structure grown by metal organic chemical vapour deposition. As-grown and thermally annealed samples at high temperature (1000 °C, 1100 °C and 1200 °C) and high pressure (1.1 GPa) were analysed by spectroscopic techniques and the annealing effect on the photoluminescence is deeply explored. Under laser excitation of 3.8 eV at room temperature, the as-grown structure exhibits two main emission bands: a yellow band peaked at 2.14 eV and a blue band peaked at 2.8 eV resulting in white light perception. Interestingly, the stability of the white light is preserved after annealing at the lowest temperature (1000 °C), but suppressed for higher temperatures due to a deterioration of the blue quantum well emission. Moreover, the control of the yellow/blue bands intensity ratio, responsible for the white colour coordinate temperatures, could be achieved after annealing at 1000 °C. The room temperature white emission is studied as a function of incident power density and the correlated colour temperature values are found to be in the warm white range: 3260–4000 K.
Circadian Modulation of 8-Oxoguanine DNA Damage Repair
Authors: Manzella Nicola , Bracci Massimo , Strafella Elisabetta , Staffolani Sara , Ciarapica Veronica , Copertaro Alfredo , Rapisarda Venerando , Ledda Caterina , Amati Monica , Valentino Matteo , Tomasetti Marco , Stevens Richard G. , Santarelli Lory
Published: September 2015

The DNA base excision repair pathway is the main system involved in the removal of oxidative damage to DNA such as 8-Oxoguanine (8-oxoG) primarily via the 8-Oxoguanine DNA glycosylase (OGG1). Our goal was to investigate whether the repair of 8-oxoG DNA damage follow a circadian rhythm. In a group of 15 healthy volunteers, we found a daily variation of Ogg1 expression and activity with higher levels in the morning compared to the evening hours. Consistent with this, we also found lower levels of 8-oxoG in morning hours compared to those in the evening hours. Lymphocytes exposed to oxidative damage to DNA at 8:00 AM display lower accumulation of 8-oxoG than lymphocytes exposed at 8:00 PM. Furthermore, altered levels of Ogg1 expression were also observed in a group of shift workers experiencing a deregulation of circadian clock genes compared to a control group. Moreover, BMAL1 knockdown fibroblasts with a deregulated molecular clock showed an abolishment of circadian variation of Ogg1 expression and an increase of OGG1 activity. Our results suggest that the circadian modulation of 8-oxoG DNA damage repair, according to a variation of Ogg1 expression, could render humans less susceptible to accumulate 8-oxoG DNA damage in the morning hours.
Reduced greenhouse gas mitigation potential of no-tillage soils through earthworm activity
Authors: Lubbers Ingrid M. , Jan van Groenigen Kees , Brussaard Lijbert , van Groenigen Jan Willem
Published: September 2015

Concerns about rising greenhouse gas (GHG) concentrations have spurred the promotion of no-tillage practices as a means to stimulate carbon storage and reduce CO2emissions in agro-ecosystems. Recent research has ignited debate about the effect of earthworms on the GHG balance of soil. It is unclear how earthworms interact with soil management practices, making long-term predictions on their effect in agro-ecosystems problematic. Here we show, in a unique two-year experiment, that earthworm presence increases the combined cumulative emissions of CO2and N2O from a simulated no-tillage (NT) system to the same level as a simulated conventional tillage (CT) system. We found no evidence for increased soil C storage in the presence of earthworms. Because NT agriculture stimulates earthworm presence, our results identify a possible biological pathway for the limited potential of no-tillage soils with respect to GHG mitigation.
Kinetics and mechanism of 3,6′-disin apoylsucrose, tenuifoliside A, tenuifoliside B and tenuifoliside C degradation in aqueous solutions
Authors: Ni Boran , Lin Hongmei , Yin Xingbin , Qu Changhai , Lin Longfei , Ni Jian
Published: September 2015

3,6′-Disin apoylsucrose, tenuifoliside A, tenuifoliside B and tenuifoliside C are the major pharmacologically active ingredients in Radix Polygalae.
The in situ synthesis of Ag/amino acid biopolymer hydrogels as mouldable wound dressings
Authors: Zhang Zhenzhu , He Ting , Yuan Mengying , Shen Rujuan , Deng Liu , Yi Lunzhao , Sun Zhifang , Zhang Yi
Published: September 2015

Monodispersed AgNPs were in situ fabricated in a hybrid supramolecular hydrogel via a green strategy. The as-prepared nanocomposite has been proved to be a mouldable wound healing biomaterial.
Highly robust hydrogels via a fast, simple and cytocompatible dual crosslinking-based process
Authors: Costa Ana M. S. , Mano João F.
Published: September 2015

An extremely strong, tough and cell-laden chitosan-based hydrogel fabricated from a single polymeric precursor solution is reported.
Visualizing virus particle mobility in liquid at the nanoscale
Authors: Cameron Varano A. , Rahimi Amina , Dukes Madeline J. , Poelzing Steven , M. McDonald Sarah , Kelly Deborah F.
Published: September 2015

We present the first high-resolution movies of active viral assemblies in liquid using in situ TEM.
A compact planar low-energy-gap molecule with a donor–acceptor–donor nature based on a bimetal dithiolene complex
Authors: Hayashi Mikihiro , Otsubo Kazuya , Kato Tatsuhisa , Sugimoto Kunihisa , Fujiwara Akihiko , Kitagawa Hiroshi
Published: September 2015

We prepared a compact, planar, low-energy-gap molecule with donor–acceptor–donor (D–A–D) nature for the first time based on a bimetal dithiolene complex.
One-pot synthesized hierarchical zeolite supported metal nanoparticles for highly efficient biomass conversion
Authors: Wang Darui , Ma Bing , Wang Bo , Zhao Chen , Wu Peng
Published: September 2015

One-pot synthesis of hierarchical zeolite supported metal nanoparticle catalysts is realized through a base-assisted chemoselective interaction.
Differentiation among peroxide explosives with an optoelectronic nose
Authors: Li Zheng , Bassett Will P. , Askim Jon R. , Suslick Kenneth S.
Published: September 2015

The handheld optoelectronic nose can identify peroxide explosives based on their method of production.
Fabrication of Cd(ii)-MOF-based ternary photocatalytic composite materials for H2 production via a gel-to-crystal approach
Authors: Zhao Chao-Wei , Li Yan-An , Wang Xue-Ru , Chen Gong-Jun , Liu Qi-Kui , Ma Jian-Ping , Dong Yu-Bin
Published: September 2015

A ternary composite material of CdS@Cd(ii)-MOF@TiO2, which is a highly active photocatalyst for H2 production, is readily prepared by a unique TiO2 induced gel-to-crystal approach.
Preparation of a porphyrinic bis(pyridyl aldehyde) and its supramolecular complexes
Authors: Greaves Christopher R. , Alemán García Miguel Á. , Bampos Nick
Published: September 2015

A linear porphyrinic bis(pyridyl aldehyde), in combination with a linear bisphenanthroline, exclusively forms a square, heteroleptic metallosupramolecular grid.
Hierarchical Ba2(B5O9)Cl·(H2O)0.5 microspheres: surfactant-assisted facile hydrothermal synthesis, Tb3+ doping and photoluminescence properties
Authors: Chen Xiuping , Zhang Linlin , Zhang Zhaoqiang , Zhu Lin , Zhu Wancheng
Published: September 2015

Uniform hierarchical Ba2(B5O9)Cl·(H2O)0.5 microspheres containing nanorod-like sub-units were synthesized via a mild EDTA-2Na assisted hydrothermal process, which were manifested as great potential green-emitting host materials via Tb3+ doping.
Hydrothermal synthesis and photoluminescence properties of Ca9Eu(PO4)7 nanophosphors
Authors: Sun Jiacheng , Mi Xiaoyun , Lei Lijian , Pan Xiaoying , Chen Shuyi , Wang Zan , Bai Zhaohui , Zhang Xiyan
Published: September 2015

During hydrothermal synthesis, the pH value plays a crucial role in the formation of crystal morphology.
Experimental and theoretical investigation of a stable zinc-based metal–organic framework for CO2 removal from syngas
Authors: Zhong Ruiqin , Liu Jia , Huang Xing , Yu Xiaofeng , Sun Changyu , Chen Guangjin , Zou Ruqiang
Published: September 2015

The experimental and theoretical investigation of a new water-stable Zn-based metal–organic framework for CO2 removal from syngas (a binary gas mixture of CO and H2) is presented.
Crystalline adducts of the Lawsone molecule (2-hydroxy-1,4-naphthaquinone): optical properties and computational modelling
Authors: Pallipurath Anuradha , Skelton Jonathan M. , Delori Amit , Duffy Connor , Erxleben Andrea , Jones William
Published: September 2015

Crystal-engineering techniques allow the colour of the molecule in henna dye (Lawsone) to be tuned from yellow to red.
Unusual bonding modes of perfluorobenzene in its polymeric (dimeric, trimeric and tetrameric) forms: entirely negative fluorine interacting cooperatively with entirely negative fluorine
Authors: Varadwaj Pradeep R. , Varadwaj Arpita , Jin Bih-Yaw
Published: September 2015

The Laplacian of the charge density plot for the tetramer of perfluorobenzene, displaying the attraction between entirely negative fluorine atoms, as well as the windmill type intermolecular topology between those atoms.
Viscosity scaling in concentrated dispersions and its impact on colloidal aggregation
Authors: Nicoud Lucrèce , Lattuada Marco , Lazzari Stefano , Morbidelli Massimo
Published: September 2015

Viscosity scaling in concentrated dispersions is identified using Brownian dynamics simulations, and its impact on colloidal aggregation is quantified.
Facile preparation and dual catalytic activity of copper(i)–metallosalen coordination polymers
Authors: Hou Yun-Long , Li Sheng-Xia , Sun Raymond Wai-Yin , Liu Xin-Yuan , Weng Ng Seik , Li Dan
Published: September 2015

Three copper(i)–metallosalen coordination polymers (CPs), {[NiII(SalImCy)]2(CuICN)9}n (1), {[CuII(SalImCy)]2(CuICN)9}n (2) and {[NiII(SalImCy)](CuII)2·DMF}n (3) were prepared by direct combination of NiII/CuII(salen) motifs with [CuICN]n chains and Cu2I2 clusters via the metalloligand strategy.
A new ONO3− trianionic pincer ligand with intermediate flexibility and its tungsten alkylidene and alkylidyne complexes
Authors: VenkatRamani Sudarsan , Ghiviriga Ion , Abboud Khalil A. , Veige Adam S.
Published: September 2015

This report details the synthesis and characterization of the semi-flexible [ONCH2O]H3 (1) ligand and its W(vi)-alkylidene and alkylidyne complexes.
How much bulk energy storage is needed to decarbonize electricity?
Authors: Safaei Hossein , Keith David W.
Published: September 2015

Impacts of capital cost of bulk energy storage on cost of electricity supply is parametrically studied under various emissions constraints.
A novel cyclic non-ligand dual-cloud point extraction for the preconcentration of cadmium(ii) through pH regulation in food and environmental matrices
Authors: Wang Yun , Chen Hui , Han Juan , Wang Lei , Ni Liang , Wang Tingting , Tang Xu
Published: September 2015

Cd2+ was extracted through pH regulation instead of adding a complexant and the position of Cd2+ in the micelles was verified.
Fluorescence modulation of a pyrazolone dye in the solid state based on energy transfer
Authors: Liu Hu , Guo Ji-Xi , Jia Dian-Zeng , Guo Ming-Xi , Liu Lang , Wu Dong-Ling
Published: September 2015

A photochromic pyrazolone is exploited as a modulator to toggle the fluorescence of a dye “on” and “off” based on energy transfer.
Inhibition of double-stranded DNA templated copper nanoparticles as label-free fluorescent sensors for l-histidine detection
Authors: Wang Hai-Bo , Zhang Hong-Ding , Chen Ying , Liu Yan-Ming
Published: September 2015

A label-free fluorescent sensing strategy was reported for l-histidine detection by the inhibition of double-stranded DNA templated copper nanoparticles.
Tunable blue-green emitting and energy transfer of a Eu2+/Tb3+ codoped Sr3La(PO4)3 phosphor for near-UV white LEDs
Authors: Bai Qiongyu , Wang Zhijun , Li Panlai , Xu Shuchao , Li Ting , Yang Zhiping
Published: September 2015

A series of Eu2+ and Tb3+ doped Sr3La(PO4)3 phosphors have been synthesized via the high-temperature solid-state reaction method.
PEGylated Gd(OH)3 nanorods as metabolizable contrast agents for computed tomography imaging
Authors: Du Yingda , Xing Ming , Li Zhiman , Guo Wei
Published: September 2015

PEGylated Gd(OH)3 nanorods have been efficiently prepared via a facile and green hydrothermal route and used as a metabolizable computed tomography contrast agent for in vivo imaging.
Copper-catalyzed C(sp3)–H functionalization of ketones with vinyl azides: synthesis of substituted-1H-pyrroles
Authors: Donthiri Ramachandra Reddy , Samanta Supravat , Adimurthy Subbarayappa
Published: September 2015

A novel copper-catalyzed C(sp3)–H functionalization of ketones with vinyl azides for the synthesis of substituted pyrroles has been developed.
The effect of amino substituents on the interactions of quinazolone derivatives with c-KIT G-quadruplex: insight from molecular dynamics simulation study for rational design of ligands
Authors: Moghaddam Kiana Gholamjani , Hashemianzadeh Seyed Majid
Published: September 2015

Our study provides insight into the effect of different substituents on the G-quadruplex–ligand interactions which helps us rational ligand design.
The non-innocent nature of graphene oxide as a theranostic platform for biomedical applications and its reactivity towards metal-based anticancer drugs
Authors: Mokdad Audrey , Dimos Konstantinos , Zoppellaro Giorgio , Tucek Jiri , Perman Jason A. , Malina Ondrej , Andersson K. Kristoffer , Ramanatha Datta Kasibhatta Kumara , Froning Jens Peter , Zboril Radek
Published: September 2015

The self-assembly process of a mononuclear iron(ii) complex as anticancer agent with graphene oxide (GO) unveils the ability of GO to oxidize the metal drug.
Highly flexible and transparent metal grids made of metal nanowire networks
Authors: Lee Chulhee , Kim Chuntae , Jeong Minseok , Kim Jeonghyo , Lee Jaewook , Oh Jin-Woo , Lee Jaebeom , Kim Soo Hyung , Park Simon S. , Kim Jong-Man
Published: September 2015

Well-established microfabrication techniques are employed to demonstrate a new architecture of metal grids made of metal nanowire networks for flexible and transparent conductive electrode applications.
Effects of spermine on the morphology, digestive enzyme activities, and antioxidant status of jejunum in suckling rats
Authors: Cao Wei , Liu Guangmang , Fang Tingting , Wu Xianjian , Jia Gang , Zhao Hua , Chen Xiaoling , Wu Caimei , Wang Jing , Cai Jingyi
Published: September 2015

Spermine is a ubiquitous cellular component that plays vital roles in the maintenance of nucleic acids, regulation of kinase activities, protein synthesis, control of ion channel activities and renewal of the gut epithelium.
Poly(γ-glutamic acid)-stabilized iron oxide nanoparticles: synthesis, characterization and applications for MR imaging of tumors
Authors: Yu Zhibo , Peng Chen , Luo Yu , Zhu Jianzhi , Chen Chen , Shen Mingwu , Shi Xiangyang
Published: September 2015

Poly(γ-glutamic acid)-stabilized iron oxide nanoparticles can be formed via a one-step mild reduction for MR imaging of tumors.
Small molecular thienoquinoidal dyes as electron donors for solution processable organic photovoltaic cells
Authors: Su Mei-Ju , Huang Jin-Hua , Zhang Li-Peng , Zhang Qian-Qian , Zhan Chuan-Lang , Zhou Xue-Qin , Yang Lian-Ming , Song Yanlin , Jiang Ke-Jian
Published: September 2015

Two small molecular quinoidal thiophene dyes, featuring low molecular weight, high molar extinction coefficient, and narrow band-gap, have been synthesized as donors for organic photovoltaic cells, giving a best power conversion efficiency of 5.12%.
Penchinones A–D, two pairs of cis-trans isomers with rearranged neolignane carbon skeletons from Penthorum chinense
Authors: He Ya-Cong , Peng Cheng , Xie Xiao-Fang , Chen Ming-Hua , Li Xiao-Nian , Li Meng-Ting , Zhou Qin-Mei , Guo Li , Xiong Liang
Published: September 2015

Two pairs of cis-trans isomers with new rearranged neolignane carbon skeletons from Penthorum chinense.
Ultra-small sulphur nanoparticles configured inside a flexible organic mixed conducting network as a cathode for lithium–sulphur batteries
Authors: Sen Sudeshna , Dutta Dipak , Bhattacharyya Aninda J.
Published: September 2015

Mixed conducting S-MIEC, comprising a lithium conducting surfactant tethered on sulphur nanoparticles and wrapped up by an electron conducting polymer, displays a high degree of reversibility and fast charge transfer kinetics in Li–S batteries.
Towards efficient electrocatalysts for oxygen reduction by doping cobalt into graphene-supported graphitic carbon nitride
Authors: Liu Shaohong , Dong Yanfeng , Wang Zhiyu , Huang Huawei , Zhao Zongbin , Qiu Jieshan
Published: September 2015

A highly efficient electrocatalyst is developed by chemical coordination of cobalt species with g-C3N4 layers which are homogeneously supported on reduced graphene oxide.
Construction of multi-layered white emitting organic nanoparticles by clicking polymers
Authors: Keita H. , Guzelturk B. , Pennakalathil J. , Erdem T. , Demir H. V. , Tuncel D.
Published: September 2015

A series of blue, green and red emitting polymers that are appropriately functionalized with alkyne and azide functional groups have been prepared and clicked together to construct bi-layered and tri-layered white emitting core–shell type nanoparticles.
Redox and trace metal regulation of ion channels in the pain pathway
Authors: Evans J. Grayson , Todorovic Slobodan M.
Published: September 2015

Given the clinical significance of pain disorders and the relative ineffectiveness of current therapeutics, it is important to identify alternative means of modulating nociception. The most obvious pharmacological targets are the ion channels that facilitate nervous transmission from pain sensors in the periphery to the processing regions within the brain and spinal cord. In order to design effective pharmacological tools for this purpose, however, it is first necessary to understand how these channels are regulated. A growing area of research involves the investigation of the role that trace metals and endogenous redox agents play in modulating the activity of a diverse group of ion channels within the pain pathway. In the present review, the most recent literature concerning trace metal and redox regulation of T-type calcium channels, NMDA (N-methyl-D-aspartate) receptors, GABAA (γ-aminobutyric acid A) receptors and TRP (transient receptor potential) channels are described to gain a comprehensive understanding of the current state of the field as well as to provide a basis for future thought and experimentation.
Electronic structures of [001]- and [111]-oriented InSb and GaSb free-standing nanowires
Authors: Liao Gaohua , Luo Ning , Yang Zhihu , Chen Keqiu , Xu H. Q.
Published: September 2015

We report on a theoretical study of the electronic structures of InSb and GaSb nanowires oriented along the [001] and [111] crystallographic directions. The nanowires are described by atomistic, tight-binding models, including spin-orbit interaction. The band structures and the wave functions of the nanowires are calculated by means of a Lanczos iteration algorithm. For the [001]-oriented InSb and GaSb nanowires, the systems with both square and rectangular cross sections are considered. Here, it is found that all the energy bands are doubly degenerate. Although the lowest conduction bands in these nanowires show good parabolic dispersions, the top valence bands show rich and complex structures. In particular, the topmost valence bands of the nanowires with a square cross section show a double maximum structure. In the nanowires with a rectangular cross section, this double maximum structure is suppressed, and the top valence bands gradually develop into parabolic bands as the aspect ratio of the cross section is increased. For the [111]-oriented InSb and GaSb nanowires, the systems with hexagonal cross sections are considered. It is found that all the bands at the Γ-point are again doubly degenerate. However, some of them will split into non-degenerate bands when the wave vector moves away from the Γ-point. Although the lowest conduction bands again show good parabolic dispersions, the topmost valence bands do not show the double maximum structure. Instead, they show a single maximum structure with its maximum at a wave vector slightly away from the Γ-point. The wave functions of the band states near the band gaps of the [001]- and [111]-oriented InSb and GaSb nanowires are also calculated and are presented in terms of probability distributions in the cross sections. It is found that although the probability distributions of the band states in the [001]-oriented nanowires with a rectangular cross section could be qualitatively described by one-band effective mass theory, the probability distributions of the band states in the [001]-oriented nanowires with a square cross section and the [111]-oriented nanowires with a hexagonal cross section show characteristic patterns with symmetries closely related to the irreducible representations of the relevant double point groups and, in general, go beyond the prediction of a simple one-band effective mass theory. We also investigate the effects of quantum confinement on the band structures of the [001]- and [111]-oriented InSb and GaSb nanowires and present an empirical formula for the description of quantization energies of the band edge states in the nanowires, which could be used to estimate the enhancement of the band gaps of the nanowires as a result of quantum confinement. The size dependencies of the electron and hole effective masses in these nanowires are also investigated and discussed.
Influence of cavity loss on an extrinsic Fabry-Perot cavity intensity-based pressure sensor
Authors: Lű Tao
Published: September 2015

We present an extrinsic Fabry-Perot cavity intensity-based pressure sensor that mainly comprises a single-mode fiber end and an elastic monocrystalline silicon layer bonded to a silicon diaphragm. We investigated the influence of cavity loss on the performance indexes (PIS) of the intensity-based extrinsic Fabry-Perot cavity optical fiber pressure sensor. A buffer unit made of three incompressible oil cavities attenuated outside pressure and transformed pressure information into cavity length microchange information. Experimental results indicated that, under center quadrature-points within the linear regions of adjacent fringes, for an applied 40 kPa external pressure, cavity length was modulated by pressures of 69.9 kPa-109.9 kPa, 150.1 kPa-190 kPa, 220.1 kPa-259.9 kPa, and 279.9 kPa-319.9 kPa, output intensity ranges increased as 1 μW, 1.02 μW, 1.03 μW, and 1.05 μW, sensitivity increased as 0.01909 μW/kPa, 0.01986 μW/kPa, 0.02127 μW/kPa, and 0.02387 μW/kPa, but linearity degraded, as indicated by the standard deviation of linear fits of 0.02607, 0.02664, 0.02935, and 0.04879 due to cavity loss. Furthermore, the pressure ranges within the same quarter period decreased as 40 kPa, 37.45 kPa, 32.4 kPa, and 30.15 kPa. Consequently, the same lengths of linear regions within adjacent fringes of an approximately sinusoidal curve corresponded to different measurement ranges, linearities, and sensitivities. Initial cavity length must be chosen to optimize both signal strength and the PIS studied here in manufacturing this type sensor.
Anisotropy in surface-initiated melting of the triclinic molecular crystal 1,3,5-triamino-2,4,6-trinitrobenzene: A molecular dynamics study
Authors: Mathew N. , Sewell Thomas D. , Thompson Donald L.
Published: September 2015

Surface-initiated melting of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), a triclinic molecular crystal, was investigated using molecular dynamics simulations. Simulations were performed for the three principal crystallographic planes exposed to vacuum, with the normal vectors to the planes given by b × c, c × a, and a × b (where a, b, and c define the edge vectors of the unit cell), denoted as (100), (010), and (001), respectively. The best estimate of the normal melting temperature for TATB is 851 ± 5 K. The nature and extent of disordering of the crystal-vacuum interface depend on the exposed crystallographic face, with the (001) face exhibiting incomplete melting and superheating. This is attributed to the anisotropy of the inter-molecular hydrogen bonding and the propensity of the crystal to form stacking faults in directions approximately perpendicular to the (100) and (010) faces. For all three crystal orientations, formation of molecular vacancies in the lattice at the crystal-vacuum (or crystal-quasi-liquid layer) interface precedes the complete loss of order at the interface.
Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability
Authors: Palmer A. , Silevitch D. M. , Feng Yejun , Wang Yishu , Jaramillo R. , Banerjee A. , Ren Y. , Rosenbaum T. F.
Published: September 2015

We discuss techniques for performing continuous measurements across a wide range of pressure–field–temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.
Performance of local correlation methods for halogen bonding: The case of Br2–(H2O)n,n = 4,5 clusters and Br2@51262 clathrate cage
Authors: Batista-Romero Fidel A. , Pajón-Suárez Pedro , Bernal-Uruchurtu Margarita I. , Hernández-Lamoneda Ramón
Published: September 2015

The performance of local correlation methods is examined for the interactions present in clusters of bromine with water where the combined effect of hydrogen bonding (HB), halogen bonding (XB), and hydrogen-halogen (HX) interactions lead to many interesting properties. Local methods reproduce all the subtleties involved such as many-body effects and dispersion contributions provided that specific methodological steps are followed. Additionally, they predict optimized geometries that are nearly free of basis set superposition error that lead to improved estimates of spectroscopic properties. Taking advantage of the local correlation energy partitioning scheme, we compare the different interaction environments present in small clusters and those inside the 51262 clathrate cage. This analysis allows a clear identification of the reasons supporting the use of local methods for large systems where non-covalent interactions play a key role.
The role of cytosine methylation on charge transport through a DNA strand
Authors: Qi Jianqing , Govind Niranjan , Anantram M. P.
Published: September 2015

Cytosine methylation has been found to play a crucial role in various biological processes, including a number of human diseases. The detection of this small modification remains challenging. In this work, we computationally explore the possibility of detecting methylated DNA strands through direct electrical conductance measurements. Using density functional theory and the Landauer-Büttiker method, we study the electronic properties and charge transport through an eight base-pair methylated DNA strand and its native counterpart. We first analyze the effect of cytosine methylation on the tight-binding parameters of two DNA strands and then model the transmission of the electrons and conductance through the strands both with and without decoherence. We find that the main difference of the tight-binding parameters between the native DNA and the methylated DNA lies in the on-site energies of (methylated) cytosine bases. The intra- and inter-strand hopping integrals between two nearest neighboring guanine base and (methylated) cytosine base also change with the addition of the methyl groups. Our calculations show that in the phase-coherent limit, the transmission of the methylated strand is close to the native strand when the energy is nearby the highest occupied molecular orbital level and larger than the native strand by 5 times in the bandgap. The trend in transmission also holds in the presence of the decoherence with the same rate. The lower conductance for the methylated strand in the experiment is suggested to be caused by the more stable structure due to the introduction of the methyl groups. We also study the role of the exchange-correlation functional and the effect of contact coupling by choosing coupling strengths ranging from weak to strong coupling limit.
Comment on “Two-dimensional positive column structure in a discharge tube with radius discontinuity” [Phys. Plasmas 21, 113503 (2014)]
Authors: Demidova M. V. , Kudryavtsev A. A. , Kurlyandskaya I. P. , Saifutdinov A. I. , Stepanova O. M.
Published: September 2015

Zobnin et al. have published a paper [Phys. Plasmas, 21, 113503 (2014)] on a topic of discharge physics in the presence of a sharp change in cylindrical discharge geometry. In the comment it is pointed out that for untrapped electrons a full kinetic equation, which includes dependences on spatial coordinates and energies, has to be used for the electron velocity distribution function determination. It is also unclear what probe theories Zobnin et al. have used in their paper for the calculation of electron current to the discharge tube wall.
Time-dependent density-functional tight-binding method with the third-order expansion of electron density
Authors: Nishimoto Yoshio
Published: September 2015

We develop a formalism for the calculation of excitation energies and excited state gradients for the self-consistent-charge density-functional tight-binding method with the third-order contributions of a Taylor series of the density functional theory energy with respect to the fluctuation of electron density (time-dependent density-functional tight-binding (TD-DFTB3)). The formulation of the excitation energy is based on the existing time-dependent density functional theory and the older TD-DFTB2 formulae. The analytical gradient is computed by solving Z-vector equations, and it requires one to calculate the third-order derivative of the total energy with respect to density matrix elements due to the inclusion of the third-order contributions. The comparison of adiabatic excitation energies for selected small and medium-size molecules using the TD-DFTB2 and TD-DFTB3 methods shows that the inclusion of the third-order contributions does not affect excitation energies significantly. A different set of parameters, which are optimized for DFTB3, slightly improves the prediction of adiabatic excitation energies statistically. The application of TD-DFTB for the prediction of absorption and fluorescence energies of cresyl violet demonstrates that TD-DFTB3 reproduced the experimental fluorescence energy quite well.
Refined crystal field model for the piezospectroscopy analysis of stresses in polycrystalline alumina
Authors: Margueron Samuel , Clarke David R.
Published: September 2015

Stresses produce systematic shifts in the R-line luminescence from Cr3+ ions in aluminium oxide. The two calculational models for determining the stress from observed R-line shifts are compared and combined with new measurements, made under a variety of different stress conditions, to determine refined crystal field model parameters for the piezospectroscopic shifts with stress. In addition to previous, well established results, it is found that the R2-luminescence line shifts linearly with the hydrostatic component of stress, (σ11 + σ22 + σ33), even under non-hydrostatic stresses. The separation of the R1 and R2 lines is not linear with the non-hydrostatic stress and increases from biaxial to uniaxial stress states. Excellent agreement with experimental data for polycrystalline materials under uniaxial and biaxial stresses was found when averaging the stresses using the Voigt approximation. However, the R2-R1 peak separation may be affected by the stress dependence of the spectral shape or stress relaxation under the highest stresses.
Interaction of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide with an electrospun PVdF membrane: Temperature dependence of the concentration of the anion conformers
Authors: Vitucci F. M. , Palumbo O. , Trequattrini F. , Brubach J.-B. , Roy P. , Meschini I. , Croce F. , Paolone A.
Published: September 2015

We measured the temperature dependence of the infrared absorption spectrum of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PY R14-TFSI) between 160 and 330 K, through all the phase transitions presented by this compound. The comparison of the experimental spectra with the calculated vibration modes of different conformers of the ions composing the ionic liquid allowed to detect the presence of both conformers of TFSI in the liquid, supercooled, and glass phases, while only the trans-conformer is retained in both solid phases. When the ionic liquid swells a polyvinylidenefluoride (PVdF) electrospun membrane, the cis-rotamer is detected in all phases, since the interaction between the polymer and the ionic liquid inhibits the complete transformation of TFSI into the trans-conformer in the solid phases. Computational results confirm that in the presence of a PVdF chain, cis-TFSI becomes the lowest energy conformer. Therefore, the interaction with the polymer alters the physical properties of the ionic liquid.
Exact calculations of survival probability for diffusion on growing lines, disks, and spheres: The role of dimension
Authors: Simpson Matthew J. , Baker Ruth E.
Published: September 2015

Unlike standard applications of transport theory, the transport of molecules and cells during embryonic development often takes place within growing multidimensional tissues. In this work, we consider a model of diffusion on uniformly growing lines, disks, and spheres. An exact solution of the partial differential equation governing the diffusion of a population of individuals on the growing domain is derived. Using this solution, we study the survival probability, S(t). For the standard non-growing case with an absorbing boundary, we observe that S(t) decays to zero in the long time limit. In contrast, when the domain grows linearly or exponentially with time, we show that S(t) decays to a constant, positive value, indicating that a proportion of the diffusing substance remains on the growing domain indefinitely. Comparing S(t) for diffusion on lines, disks, and spheres indicates that there are minimal differences in S(t) in the limit of zero growth and minimal differences in S(t) in the limit of fast growth. In contrast, for intermediate growth rates, we observe modest differences in S(t) between different geometries. These differences can be quantified by evaluating the exact expressions derived and presented here.
Photoelectron spectroscopic and theoretical study of the [HPd(η2-H2)]− cluster anion
Authors: Zhang Xinxing , Robinson Paul J. , Ganteför Gerd , Alexandrova Anastassia , Bowen Kit H.
Published: September 2015

Anion photoelectron spectroscopic and theoretical studies were conducted for the PdH− and PdH3− cluster anions. Experimentally observed electron affinities and vertical detachment energies agree well with theoretical predictions. The PdH3− anionic complex is made up of a PdH− sub-anion ligated by a H2 molecule, in which the H–H bond is lengthened compared to free H2. Detailed molecular orbital analysis of PdH−, H2, and PdH3− reveals that back donation from a d-type orbital of PdH− to the σ* orbital of H2 causes the H–H elongation, and hence, its activation. The H2 binding energy to PdH− is calculated to be 89.2 kJ/mol, which is even higher than that between CO and Pd. The unusually high binding energy as well as the H–H bond activation may have practical applications, e.g., hydrogen storage and catalysis.
Water adsorption induced in-plane domain switching on BaTiO3 surface
Authors: Li X. , Bai Y. , Wang B. C. , Su Y. J.
Published: September 2015

In this study, the influences of the adsorption of water molecules on the changes in the atomic and electric structures of BaTiO3 surface were investigated using ab initio calculation. Water molecules are molecularly and dissociatively adsorbed on the BaTiO3 surface, which makes electrons transfer from water molecules to the BaTiO3 surface. The redistribution of electrons in the BaTiO3 surface layers weakens the Ba-O interactions and strengthens the Ti-O interactions, so that the Ti atom shifts in TiO2 plane, i.e., an in-plane domain switching. The adsorption of water molecules on BaTiO3 surfaces also results in a reduction in the surface rumpling.