bluuebunny/crossref_metadata_2025 huggingface dataset:
Photo-induced isomerization of ethylene-bridged azobenzene explored by ab initio based non-adiabatic dynamics simulation: A comparative investigation of the isomerization in the gas and solution phases
Authors: Cao Jun , Liu Li-Hong , Fang Wei-Hai , Xie Zhi-Zhong , Zhang Yong
Published: April 2013

Azobenzene is one of the most widely used photoactive units and recently an ethylene-bridged azobenzene (BAB) was reported to have greatly enhanced conversion efficiency, quantum yield, and other favorable properties. As the first step towards exploring its photo-switchable character in real systems, we report here a systematic study on the photoisomerization dynamics between trans (E) and cis (Z) isomers in the gas phase and the CH3OH solution, using ab initio based surface hopping and molecular dynamics, which is the first report of dynamics simulation to reveal the environmental effects on BAB photoreactions. Results show that while the relatively faster S1 relaxation of the photo-induced E → Z process is only mildly affected by the solvent effect, the relatively slower S1 relaxation of the reverse reaction becomes even slower in the solution compared to the gas phase. The subsequent S0 dynamics from the conical intersection between S1 and S0 (CI_E) to Z is accelerated in solution compared to the gas phase because of avoided re-crossing to the S1 state, while the S0 dynamics from the conical intersection between S1 and S0 (CI_Z) to E are basically the same in both phases. Overall, the solvent effect was found to enhance the back-and-forth photo-switch efficiency between the Z and E isomers compared to the gas phase, while the quantum yields are reduced. But the solution yields of both the forward and backward photoreactions are still around 0.4. Therefore, BAB may have good photo-responsive properties if used as a photoactive unit in real systems. These results will facilitate future experimental and theoretical studies in this area to help design new azobenzene derivatives as photoactive units in biological processes, nanoscale devices, and photo-responsive materials.
A new approach to kinetics study of the anhydrite crystallization at 373 K using a diamond anvil cell with Raman spectroscopy
Authors: Liu C. J. , Zheng H. F.
Published: April 2013

A new approach to the kinetics study of anhydrite (CaSO4) crystallization has been performed in situ using a hydrothermal diamond anvil cell with Raman spectroscopy in the pressure range 896–1322 MPa and a constant temperature of 373 K. Transformed volume fraction X(t) was determined from Raman peak intensity of the sulfate ion in aqueous solution. The transformation-time plots display a sigmoidal shape with time, which indicates that the reaction rate is different at each stage of anhydrite crystallization. At 373 K, the rate constant k increases from 1.14 × 10−4 s−1 to 1.86 × 10−3 s−1, demonstrating a positive effect of pressure on the overall rate at isothermal condition. We first achieved the molar volume change (ΔVm) equal to −1.82 × 10−5 m3/mol in the course of anhydrite crystallization through Avrami kinetic theory, showing a process of reduction in volume at high pressure and high temperature. According to the exponent n derived from our experiments, a grain-boundary nucleation and diffusion-controlled growth kinetically dominates the crystallization of anhydrite.
Validation of velocity map imaging conditions over larger areas
Authors: Reid Mike , Koehler Sven P. K.
Published: April 2013

We have established through simulations and experiments the area over which Velocity Map Imaging (VMI) conditions prevail. We designed a VMI setup in which we can vary the ionization position perpendicular to the center axis of the time-of-flight spectrometer. We show that weak extraction conditions are far superior over standard three-plate setups if the aim is to increase the ionization volume without distorting VMI conditions. This is important for a number of crossed molecular beam experiments that already utilize weak extraction conditions, but to a greater extent for surface studies where fragments are desorbed or scattered off a surface in all directions. Our results on the dissociation of NO2 at 226 nm show that ionization of the fragments can occur up to ±5.5 mm away from the center axis of the time-of-flight spectrometer without affecting resolution or arrival position.
New families of superintegrable systems from Hermite and Laguerre exceptional orthogonal polynomials
Authors: Marquette Ian , Quesne Christiane
Published: April 2013

In recent years, many exceptional orthogonal polynomials (EOP) were introduced and used to construct new families of 1D exactly solvable quantum potentials, some of which are shape invariant. In this paper, we construct from Hermite and Laguerre EOP and their related quantum systems new 2D superintegrable Hamiltonians with higher-order integrals of motion and the polynomial algebras generated by their integrals of motion. We obtain the finite-dimensional unitary representations of the polynomial algebras and the corresponding energy spectrum. We also point out a new type of degeneracies of the energy levels of these systems that is associated with holes in sequences of EOP.
An (e, 2e + ion) investigation of dissociative ionization of methane
Authors: Xu Shenyue , Ma Xinwen , Ren Xueguang , Senftleben Arne , Pflüger Thomas , Yan Shuncheng , Zhang Pengju , Yang Jie , Ullrich Joachim , Dorn Alexander
Published: April 2013

We present in this paper an (e, 2e + ion) investigation of the dissociative ionization of methane by 54 eV electron impact employing the advanced reaction microscope. By measuring two electrons and the ion in the final state in triple coincidence, the species of the ions are identified and the energies deposited into the target are determined. The species and the kinetic energies of the fragmented ion show strong dependence on the intermediate states of the parent ion. Possible decay pathways for the production of different species of ions are analyzed.
Effect of heavy hydrogen isotopes on the vibrational line shape for supercritical water through rotational couplings
Authors: Yoshida Ken , Matubayasi Nobuyuki , Uosaki Yasuhiro , Nakahara Masaru
Published: April 2013

The rotational couplings, which determine the infrared spectral line shape in the low-density supercritical water, were analyzed as functions of the density and the temperature by applying molecular dynamics simulation to a flexible water model, SPC/Fw and by varying the moment of inertia of the water through substitution for the H atom in H2O by heavy hydrogen isotopes. The differences in the frequency and the relative intensity between the sharp center peak and the rotational broad side-bands were analyzed for the O−H, O−D, and O−T stretch spectra. The frequency differences between the sharp center peak and the rotational broad side-bands are linearly correlated with the inverse of the moment of inertia of the isotope-substituted water species. The intensity of the sharp peak is associated with the long-time component of the reorientational time correlation function for the stretching bond vector. At 400 °C, where a substantial amount of hydrogen bonds are dynamically persisting, an intensity decrease in the rotational broad side-bands was observed with increasing density from 0.01 to 0.40 g cm−3, respectively, corresponding to 0.56 and 22.2 M (=mol dm−3), orders of magnitude higher than the ideal gas densities. This arises from the decrease in the correlation time of the angular velocity and the rotational couplings due to an increase in the hydrogen-bonding perturbation. The intensity decrease of the rotational side-bands with increasing density is more significant for the water isotopes with heavier hydrogens. At a high temperature of 1200 °C, the rotational side-bands at 0.01 to 0.05 g cm−3 were more distinct than those at 400 °C, and even at a medium density of 0.40 g cm−3 a significant signal broadening due to the rotational couplings was clearly observed because of the accelerated rotational momentum. The vibrational spectrum cannot be decomposed into definite chemical clusters for the thermodynamic and kinetic analysis because of the dynamic origin.
Growth and strain relaxation of GaAs and GaP nanowires with GaSb shells
Authors: Salehzadeh O. , Kavanagh K. L. , Watkins S. P.
Published: April 2013

We report on the growth of GaSb shells on Au-catalyzed GaAs or GaP nanowires (NWs) using metalorganic vapor phase epitaxy. The large lattice mismatch between GaSb and GaAs (GaP), 7.8% (11.8%), results in surface roughening and GaSb island formation via the Stranski-Krastanov (S-K) growth mode. Based on transmission electron microscopy (TEM) analysis, coherent GaSb islands on GaAs NWs could be grown up to a thickness of 1.8 nm for a core diameter of 34 ± 5 nm. For greater shell thickness of 9 ± 3 nm, equal axial and radial strain relaxation occurred increasing from 74% ± 3% for GaAs/GaSb NWs and 91% ± 2% for GaP/GaSb NWs to 100% with increasing core diameter from 15 ± 2 nm to 55 ± 3 nm. Axial strain is relieved by periodic misfit dislocations with edge components parallel to the growth direction. Tangential relaxation is presumed to occur partially by roughening via the S-K growth mode but dislocations with edge components perpendicular to the growth direction were not detected. Raman scattering measurements were performed on ensembles of NWs and the absolute residual strain in the core and shell were determined from the shift of the zone-center phonon modes. Raman results were consistent with the TEM analysis. It was found that the residual strain is higher in GaAs/GaSb NWs (7.3%) compared to GaP/GaSb NWs (1.7%).
Effects of intrinsic defects on methanthiol monolayers on Cu(111): A density functional theory study
Authors: Fan Xiao-Li , Yang Yong-Liang , Liu Yan , Lau Woon-Ming
Published: April 2013

Density functional theory calculations were used to examine the effects of intrinsic surface defects of Cu(111) on the adsorption of methylthiol (CH3SH). The examination covers both the initial non-dissociative adsorption and the subsequent dissociation reaction pathways to form intermediate and final reaction products. By comparing the most probable adsorption structures likely formed after the adsorption of CH3SH on Cu(111) with and without the presence of adatoms (Cuad) and vacancies, this computational work offers new insights about the geometry and thermodynamic stability of these structures. Particularly, it reveals a new type of surface complexes having two CH3S bonding to one Cuad (referred therein as CH3S–Cuad–CH3S). In addition, this work also yields new reaction dynamics results on transition states and activation barriers. The results reveal that the presence of Cuad indeed significantly changes the kinetics of adsorption and dissociation of CH3SH on Cu(111). The most kinetically favorable reaction pathway turns out to be that involving the formation of a special surface complex formed by one Cuad plus two CH3S fragments from the dissociation of CH3SH, with the two S atoms located at the bridge sites of Cu(111). Finally, this work also gives simulated scanning tunneling microscopic images for the most important adsorption species in the course of the transition from CH3SH/Cu(111) to CH3S/Cu(111), which may stimulate future experimental studies of self-assembled monolayers on practical metal substrates such as thiols on copper.
Photonic crystal slot-microcavity circuit implemented in silicon-on-insulator: High Q operation in solvent without undercutting
Authors: Hamed Mirsadeghi S. , Schelew Ellen , Young Jeff F.
Published: April 2013

We report the fabrication and characterization of a silicon-based photonic integrated circuit consisting of a photonic crystal slot-cavity, waveguides, and grating couplers, designed as a robust, easy-to-use device for enhancing light-matter interactions at a precise location inside a fluidic medium, while minimizing fabrication complexity. Measured Q values in excess of 7500 for circuits immersed in hexane and operating near 1.5 μm are obtained, in good agreement with simulations. The detection limit for changes in solvent refractive index unit (RIU) for these structures, which have not been optimized, is 2.3×10−5 RIU.
Improved performance of vanadium redox battery using methylsulfonic acid solution as supporting electrolyte
Authors: He Zhangxing , Li Zhen , Zhou Zhi , Tu Feiyue , Jiang Yifan , Pan Chunyue , Liu Suqin
Published: April 2013

Methylsulfonic acid (MSA) as supporting electrolyte for vanadium redox battery was studied and evaluated by thermal stability test, cyclic voltammetry, linear sweep voltammetry, and charge-discharge technique. The results show that the V(V)-MSA solution has better thermal stability than the sulfuric acid solutions, which may be due to the formation of VO(CH3SO3)2 to prevent further condensation. The diffusion coefficient of V(IV) in MSA can reach up to (0.94–1.52) × 10−6 cm2 s−1, much higher than that in H2SO4 solution (1.40–2.20 × 10−7 cm2 s−1). Polarization curves show the improved reaction kinetics of V(IV)/V(V) in MSA solution, lower charge transfer resistance (5.61 Ω), larger exchange current density (4.57 × 10−3 A cm−2), and rate constant (4.74 × 10−5 cm s−1) compared with the H2SO4 solution. The vanadium redox batteries with the MSA electrolytes demonstrated excellent reversibility and high energy efficiency (83.1%), 2.7% higher than that in H2SO4 solution. The preliminary exploration shows that MSA has a promising application prospect in vanadium redox battery and is worthy for further study.
Anisotropic film growth of iron-phthalocyanine on graphene on a Ni(111) substrate: Roles of molecule-substrate and intermolecular interaction
Authors: Dou Weidong , Yang Qingdan , Lee Chun-Sing
Published: April 2013

Growths of iron-phthalocyanine (FePc) and copper-phthalocyanine (CuPc) on graphene were experimentally investigated. Both FePc and CuPc molecules were found to preferentially nucleate aside of graphene wrinkles at initial deposition stage. CuPc prefers to nucleate into extended two-dimensional islands, while FePc always tends to grow into one-dimensional (1D) fiber-like islands at higher coverage stage. Orientations of the 1D FePc fibers are 30° off from each other. Nucleation behaviors of FePc on graphene/Ni(111) substrate are different to those on bare Ni(111) or graphene/Cu(111) substrate, evidencing the importance of coupling between graphene and the underlying Ni(111) substrate in the ordered growth of 1D FePc film.
Variable-focus lens with 30 mm optical aperture based on liquid–membrane–liquid structure
Authors: Wang Lihui , Oku Hiromasa , Ishikawa Masatoshi
Published: April 2013

We report a liquid lens with a liquid–membrane–liquid structure in order to realize a variable-focus lens with a large optical aperture. We studied a typical liquid lens with a liquid–liquid structure and examined its physical limitation, namely, the capillary length, restricting the design of a larger-aperture liquid lens. We propose using elastic force instead of surface tension to acquire a much longer capillary length. We demonstrated that this approach can achieve sufficiently long capillary length when external pressure is loaded. A prototype lens with 30 mm aperture was constructed, and a resolution of 8.00 lp/mm was realized.
Modeling the evaporation rate of cesium off tungsten based controlled porosity dispenser photocathodes
Authors: Pan Z. , Jensen K. L.
Published: April 2013

The evaporation of cesium from a tungstensurface is modeled using an effective one-dimensional potential well representation of the binding energy. The model accounts for both local and global interactions of cesium with the surface metal as well as with other cesium atoms. The theory is compared with the data of Taylor and Langmuir [Phys. Rev.44, 423 (1933)10.1103/PhysRev.44.423] comparing evaporation rates to sub-monolayer surface coverage of cesium, gives good agreement, and reproduces the nonlinear behavior of evaporation with varying coverage and temperature.
Electronic structure and quasiparticle bandgap of silicene structures
Authors: Huang Shouting , Kang Wei , Yang Li
Published: April 2013

We report first-principles results on the electronic structure of silicene. For planar and simply buckled silicenes, we confirm their zero-gap nature and show a significant renormalization of their Fermi velocity by including many-electron effects. However, the other two recently proposed silicene structures exhibit a finite bandgap, indicating that they are gapped semiconductors instead of expected Dirac-fermion semimetals. This finite bandgap is preserved with the Ag substrate included. Moreover, our GW calculation reveals enhanced many-electron effects in these two-dimensional structures. Finally, the bandgap of the latter two structures can be tuned in a wide range by applying strain.
A survey of the natural variation in biomechanical and cell wall properties in inflorescence stems reveals new insights into the utility of Arabidopsis as a wood model
Authors: MacMillan Colleen P. , O'Donnell Philip J. , Smit Anne-Marie , Evans Rob , Stachurski Zbigniew H. , Torr Kirk , West Mark , Baltunis Jacqueline , Strabala Timothy J.
Published: April 2013

The natural trait variation in Arabidopsis thaliana (L.) Heynh. accessions is an important resource for understanding many biological processes but it is underexploited for wood-related properties. Twelve A. thaliana accessions from diverse geographical locations were examined for variation in secondary growth, biomechanical properties, cell wall glycan content, cellulose microfibril angle (MFA) and flowering time. The effect of daylength was also examined. Secondary growth in rosette and inflorescence stems was observed in all accessions. Organised cellulose microfibrils in inflorescence stems were found in plants grown under long and short days. A substantial range of phenotypic variation was found in biochemical and wood-related biophysical characteristics, particularly for tensile strength, tensile stiffness, MFA and some cell wall components. The four monosaccharides galactose, arabinose, rhamnose and fucose strongly correlated with each other as well as with tensile strength and MFA, consistent with mutations in arabinogalactan protein and fucosyl- and xyloglucan galactosyl-transferase genes that result in decreases in strength. Conversely, these variables showed negative correlations with lignin content. Our data support the notion that large-scale natural variation studies of wood-related biomechanical and biochemical properties of inflorescence stems will be useful for the identification of novel genes important for wood formation and quality, and therefore biomaterial and renewable biofuel production.
Anatomic distribution of Neisseria gonorrhoeae, Chlamydia trachomatis and Mycoplasma genitalium infections in men who have sex with men
Authors: Reinton N. , Moi H. , Olsen A. O. , Zarabyan N. , Bjerner J. , Tønseth T. M. , Moghaddam A.
Published: April 2013

Background
New cases of gonorrhoea (Neisseria gonorrhoeae) and chlamydia (Chlamydia trachomatis) infections have been steadily increasing in Scandinavian countries over the last decade. There is a particular urgency in reducing new infections as isolation of multiple drug resistant strains of gonorrhoea is becoming more frequent. The aim of this study was to determine the prevalence and sites of infection of common sexually transmissible infections (STIs) in men who have sex with men (MSM). Methods: We have performed a retrospective analysis of the three major STIs, gonorrhoea, chlamydia and Mycoplasma genitalium in urogenital, anorectal and oropharyngeal samples from MSM that attended two STI clinics in Oslo. Results: One hundred and thirty-six men (6.0%) out of 2289 MSM tested were found to be positive for gonorrhoea using a porA gene targeted nucleic acid amplification test (NAAT). Of these, 106 (77.9%) would not have been identified through testing first-void urine alone. Two hundred and twenty eight (10.0%) patients from 2289 tested were found to be positive for chlamydia, 164 (71.9%) of which were identified through anorectal specimens. Ninety-one (5.1%) patients from 1778 tested were found to be positive for M. genitalium, with 65 (71.4%) identified through testing of anorectal specimens. Conclusions: Our results supports the European findings that the MSM population carries a high burden of STIs and that testing the anorectum and oropharynx will identify a significantly higher percentage of infected patients and reservoirs of STIs.
Harnessing the value of beneficial micro-organisms: role of regulatory landscapes - Mini Review.
Authors: Sundh I. , Wilcks A. , Goettel M. S.
Published: April 2013

Beneficial micro-organisms, isolated from various environments, can be 'domesticated' and used in agriculture, food and biotechnology. An analysis is required for new microbial strains and applications to ensure safety. Various regulatory frameworks apply and in some instances registration is required before marketing. Regulatory demands must be tuned to actual risk. 'Overregulation' could hamper the implementation of useful products, whereas the lack of appropriate oversight could negatively affect public health or the environment. There is a need for further development and consolidation of safety assessment of beneficial micro-organisms as a unique research discipline and of risk-benefit analysis where risks are weighed against benefits.
The Feasibility of Telephone Follow-Up Interviews for Monitoring Treatment Outcomes of Australian Residential Drug and Alcohol Treatment Programs
Authors: Deane Frank P. , Kelly Peter J. , Crowe Trevor P. , Lyons Geoffrey C. B. , Cridland Elizabeth K.
Published: April 2013

Background

Telephone follow-up interviewing is one method of monitoring treatment outcomes of individuals involved in drug and alcohol treatment programs. The present study is the first to examine the feasibility and generalizability of data obtained from telephone follow-up interviews after drug and alcohol treatment in Australia.

Methods

Participants attended 1 of 8 Salvation Army Recovery Service Centres where staff administered outcome measures at intake. Three-month postdischarge telephone follow-up interviews were conducted by researchers from the Illawarra Institute for Mental Health, University of Wollongong.

Results

A sample of 700 clients was obtained for follow-up (582 males; 118 females). A 51% follow-up rate was achieved at a cost of US$82 per completed interview. No significant differences in baseline characteristics between responding and nonresponding participants were found.

Conclusions

Overall, the telephone methodology was shown to be feasible and relatively inexpensive. However, the introduction of outcome measures at the service level in parallel with follow-up data collection procedures complicated the collection of response data. The burden of introducing outcome measures in residential services may be reduced by utilizing a phased implementation strategy.
Individual Differences in the Delayed Execution of Prospective Memories
Authors: Ball B. Hunter , Knight Justin B. , Dewitt Michael R. , Brewer Gene A.
Published: April 2013

Working memory processes play a critical role in actively maintaining, rehearsing, and retrieving goal-relevant information during cognitively engaging tasks. In the current study, we examined individual differences in prospective memory between young adults with high versus low working memory capacity (WMC) when they had to momentarily delay their intentions for either 6 or 42 s. In Experiments 1 and 2, high-WMC individuals performed significantly better at both delay intervals than did low-WMC individuals under standard ongoing task conditions. In Experiment 2, we included an interrupting task during the longer delay that decreased performance in the low-WMC relative to the high-WMC individuals. These results suggest that prospective memory performance is generally impaired across all retention intervals in low-WMC individuals, and that high-WMC individuals may be better able to retrieve the intention from long-term memory even when attention is interrupted by intervening activities.
Robustly non-hyperbolic transitive endomorphisms on 𝕋²
Authors: He Baolin , Gan Shaobo
Published: April 2013

We prove that for any regular endomorphism

f
f

on a 2-torus

T

2

\mathbb {T}^2

which is not one to one, there is a regular map

g
g

homotopic to

f
f

such that

g
g

is

C
1

C^1

robustly non-hyperbolic transitive. We also introduce interesting blender phenomena (a fat horseshoe) of 2-dimensional endomorphisms, which play an important role in our construction of some examples.
A tool for RNA sequencing sample identity check
Authors: Huang Jinyan , Chen Jun , Lathrop Mark , Liang Liming
Published: April 2013

Summary: RNA sequencing data are becoming a major method of choice to study transcriptomes, including the mapping of gene expression quantitative trait loci (eQTLs). RNA sample contamination or swapping is a serious problem for downstream analysis and may result in false discovery and lose power to detect the true biological relationships. When genetic data are available, for example, in eQTL studies or samples have been previously genotyped or DNA sequenced, it is possible to combine genetic data and RNA-seq data to detect sample contamination and resolve sample swapping problems. In this article, we introduce a tool (IDCheck) that allows easy assessment of concordance between genotype (from SNP arrays or DNA sequencing) and gene expression (RNA-seq) samples. IDCheck compares the identity of RNA-seq reads and SNP genotypes using a likelihood-based method. Based on maximum likelihood estimates of relevant parameters, we can detect sample contamination and identify correct sample pairs when swapping occurs. Our tool provides an efficient and convenient way to evaluate and resolve these problems.

Availability: A complete description of the software is included on the application home page. The software is freely available in the public domain at http://eqtl.rc.fas.harvard.edu/idcheck/.

Contact:  lliang@hsph.harvard.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Twin enigmatic microseismic sources in the Gulf of Guinea observed on intercontinental seismic stations
Authors: Xia Yingjie , Ni Sidao , Zeng Xiangfang
Published: April 2013

Based on studies of continuous waveform data recorded on broad-band seismograph stations in Africa, Europe and North America, we report evidences for two temporally persistent and spatially localized monochromatic vibrating sources (around 0.036 and 0.038 Hz, respectively) in the Gulf of Guinea, instead of just one source (0.038 Hz or 26 s) found 50 yr ago. The location of the 0.036 Hz source is close to the Sao Tome Volcano, therefore it may be related to volcano processes. However, the 0.038 Hz source cannot be explained with known mechanisms, such as tectonic or oceanic processes. The most likely mechanism is volcano processes, but there is no reported active volcano in source region. Such repetitive vibration sources may provide valuable tools for detecting temporal variation of crustal structure of the Earth.
Probiotics in colorectal cancer (CRC) with emphasis on mechanisms of action and current perspectives
Authors: Kahouli Imen , Tomaro-Duchesneau Catherine , Prakash Satya
Published: April 2013

Colorectal cancer (CRC) is the third most common form of cancer. Diverse therapies such as chemotherapy, immunotherapy and radiation have shown beneficial effects, but are limited because of their safety and toxicity. Probiotic formulations have shown great promise in CRC as preventive and early stage therapeutics. This review highlights the importance of a balanced intestinal microbiota and summarizes the recent developments in probiotics for treating CRC. Specifically, this report describes evidence of the role of probiotics in modulating the microbiota, in improving the physico-chemical conditions of the gut and in reducing oxidative stress. It also discusses the mechanisms of probiotics in inhibiting tumour progression, in producing anticancer compounds and in modulating the host immune response. Even though some of these effects were observed in several clinical trials, when probiotic formulations were used as a supplement to CRC therapies, the application of probiotics as biotherapeutics against CRC still needs further investigation.
Biofilm formation by Staphylococcus capitis strains isolated from contaminated platelet concentrates
Authors: Greco-Stewart Valerie S. , Ali Hamza , Kumaran Dilini , Kalab M. , Rood Ineke G. H. , de Korte Dirk , Ramírez-Arcos Sandra
Published: April 2013

Bacterial contamination of platelet concentrates (PCs) poses the greatest infectious risk in modern transfusion medicine despite the implementation of measures such as improved skin disinfection and first aliquot diversion. The majority of PC contaminants are commensal skin flora introduced by venipuncture at the time of blood collection. The predominant organisms are Gram-positive coagulase-negative staphylococci such as Staphylococcus capitis. This bacterium has been implicated in numerous instances of infection and sepsis, likely for its ability to form surface-associated communities of micro-organisms encased in extracellular materials, known as biofilms. In the present study, five strains of S. capitis isolated from contaminated PCs were assessed for their ability to produce extracellular polysaccharide (slime), a canonical indicator of biofilm-formation ability, on Congo red agar plates. Biofilm formation was evaluated in both glucose-enriched trypticase soy broth (TSBg) and in PCs by using a crystal violet staining assay. The chemical nature of the biofilms was evaluated by disruption assays using sodium metaperiodate and proteinase K. In addition, biofilm architecture was observed by scanning electron microscopy. The presence of the biofilm-associated icaR and icaADBC genes was also examined by PCR. While only two out of the five S. capitis strains formed biofilms in TSBg, all strains formed biofilms in PCs. The ability of strains to produce extracellular polysaccharide and their possession of wild-type ica genes were not exclusive predictors of biofilm formation in TSBg or PCs; different profiles of biofilm markers were observed among isolates. This is likely due to the proteinaceous composition of the S. capitis biofilm matrix. Interestingly, an ica-negative, non-slime-producing isolate was capable of biofilm formation in PCs. Together, these data indicate that the platelet storage environment stimulates biofilm formation in S. capitis in the absence of extracellular polysaccharide production and that multiple bacterial factors and regulatory elements are likely involved in biofilm formation in this milieu.
The involvement of Helicobacter pylori thioredoxin-1 in gastric carcinogenesis
Authors: Shi Yanyan , Liu Linna , Zhang Ting , Shen Lijuan , Liu Lin , Zhang Jing , Zhang Yuexia , Wang Xuehong , Yang Shengsen , Lu Fengmin , Chen Xiangmei , Ding Shigang
Published: April 2013

Helicobacter pylori infection is related to the development of gastric diseases. Various virulence factors are responsible for the pathogenic mechanisms of H. pylori infection. Our previous studies using two-dimensional gel electrophoresis showed that H. pylori thioredoxin-1 (Trx1) is overexpressed in gastric carcinomas. Here, we examined whether H. pylori Trx1 is a novel virulence factor associated with gastric tumorigenesis. We found that Trx1 expression in H. pylori isolated from gastric cancer tissues was significantly higher than that from tissues exhibiting gastritis. In the gastric epithelial cell line GES-1, infection of H. pylori with high Trx1 expression significantly induced cell apoptosis, decreased the expression of cyclin D1 and upregulated p21. However, in the gastric cancer cell line BGC823, high Trx1 expression in H. pylori significantly increased cell proliferation, and upregulated cyclin D1. The effects on cell lines were confirmed using the H. pylori
Trx1-knockout mutant strain. Our observations indicate that high Trx1 expression in H. pylori is associated with gastric carcinogenesis. In H. pylori, Trx1 likely participates in the pathogenesis of gastric cancer and H. pylori expressing high levels of Trx1 would be expected to be highly pathogenic in gastric diseases in China.
RAGE inhibits human respiratory syncytial virus syncytium formation by interfering with F-protein function
Authors: Tian Jane , Huang Kelly , Krishnan Subramaniam , Svabek Catherine , Rowe Daniel C. , Brewah Yambasu , Sanjuan Miguel , Patera Andriani C. , Kolbeck Roland , Herbst Ronald , Sims Gary P.
Published: April 2013

Human respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract infection. Infection is critically dependent on the RSV fusion (F) protein, which mediates fusion between the viral envelope and airway epithelial cells. The F protein is also expressed on infected cells and is responsible for fusion of infected cells with adjacent cells, resulting in the formation of multinucleate syncytia. The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor that is constitutively highly expressed by type I alveolar epithelial cells. Here, we report that RAGE protected HEK cells from RSV-induced cell death and reduced viral titres in vitro. RAGE appeared to interact directly with the F protein, but, rather than inhibiting RSV entry into host cells, virus replication and budding, membrane-expressed RAGE or soluble RAGE blocked F-protein-mediated syncytium formation and sloughing. These data indicate that RAGE may contribute to protecting the lower airways from RSV by inhibiting the formation of syncytia, viral spread, epithelial damage and airway obstruction.
Knockdown of piRNA pathway proteins results in enhanced Semliki Forest virus production in mosquito cells
Authors: Schnettler Esther , Donald Claire L. , Human Stacey , Watson Mick , Siu Ricky W. C. , McFarlane Melanie , Fazakerley John K. , Kohl Alain , Fragkoudis Rennos
Published: April 2013

The exogenous siRNA pathway is important in restricting arbovirus infection in mosquitoes. Less is known about the role of the PIWI-interacting RNA pathway, or piRNA pathway, in antiviral responses. Viral piRNA-like molecules have recently been described following infection of mosquitoes and derived cell lines with several arboviruses. The piRNA pathway has thus been suggested to function as an additional small RNA-mediated antiviral response to the known infection-induced siRNA response. Here we show that piRNA-like molecules are produced following infection with the naturally mosquito-borne Semliki Forest virus in mosquito cell lines. We show that knockdown of piRNA pathway proteins enhances the replication of this arbovirus and defines the contribution of piRNA pathway effectors, thus characterizing the antiviral properties of the piRNA pathway. In conclusion, arbovirus infection can trigger the piRNA pathway in mosquito cells, and knockdown of piRNA proteins enhances virus production.
CCL: an algorithm for the efficient comparison of clusters
Authors: Hundt R. , Schön J. C. , Neelamraju S. , Zagorac J. , Jansen M.
Published: April 2013

The systematic comparison of the atomic structure of solids and clusters has become an important task in crystallography, chemistry, physics and materials science, in particular in the context of structure prediction and structure determination of nanomaterials. In this work, an efficient and robust algorithm for the comparison of cluster structures is presented, which is based on the mapping of the point patterns of the two clusters onto each other. This algorithm has been implemented as the module CCL in the structure visualization and analysis programKPLOT.
Synthesis and fading of eighteenth-century Prussian blue pigments: a combined study by spectroscopic and diffractive techniques using laboratory and synchrotron radiation sources
Authors: Samain Louise , Grandjean Fernande , Long Gary J. , Martinetto Pauline , Bordet Pierre , Sanyova Jana , Strivay David
Published: April 2013

Prussian blue, a hydrated iron(III) hexacyanoferrate(II) complex, is a synthetic pigment discovered in Berlin in 1704. Because of both its highly intense color and its low cost, Prussian blue was widely used as a pigment in paintings until the 1970s. The early preparative methods were rapidly recognized as a contributory factor in the fading of the pigment, a fading already known by the mid-eighteenth century. Herein two typical eighteenth-century empirical recipes have been reproduced and the resulting pigment analyzed to better understand the reasons for this fading. X-ray absorption and Mössbauer spectroscopy indicated that the early syntheses lead to Prussian blue together with variable amounts of an undesirable iron(III) product. Pair distribution functional analysis confirmed the presence of nanocrystalline ferrihydrite, Fe10O14(OH)2, and also identified the presence of alumina hydrate, Al10O14(OH)2, with a particle size of ∼15 Å. Paint layers prepared from these pigments subjected to accelerated light exposure showed a tendency to turn green, a tendency that was often reported in eighteenth- and nineteenth-century books. The presence of particles of hydrous iron(III) oxides was also observed in a genuine eighteenth-century Prussian blue sample obtained from a polychrome sculpture.
Retaining the thin blue line
Authors: Gächter Martin , Savage David A. , Torgler Benno
Published: April 2013

Purpose

The purpose of this paper is to investigate the relationship between workplace factors and the intentions of police officers to quit their current department.

Design/methodology/approach

Data from a survey of Baltimore officers, designed to examine the relationship between police stress and domestic violence in police families were used. Using multivariate regression analysis, the authors focus on the officers' stated intentions to look for alternative employment, with proxies for social and workplace factors.

Findings

Higher levels of cooperation (trust), interactional justice and work‐life‐balance reduce police officers' intentions to quit. While high levels of physical and psychological strain and trauma are not correlated with intentions to quit.

Research limitations/implications

A discernible limitation of this study is the age of the data analyzed and that many changes have occurred in recent times (policing and social). It would be of great interest to repeat this study to gauge the true effect.

Practical implications

There are policy implications for retention and recruitment: it may possible to decrease the ethnic and gender gaps, through identifying officers at risk and creating programs to hold existing minorities, recruit more, whilst maintaining a strong, happy and healthy department.

Originality/value

This study examines the impact of workplace factors on quitting intention for police officers. It is demonstrated that social capital, fairness and work‐life balance are moderators for quitting, adding to the literature on worker retention, as little research has been done using multivariate analysis on quitting intentions.
Friedman, Schumpeter, and Greenspan's financial policies
Authors: Leathers Charles G. , Patrick Raines J.
Published: April 2013

Purpose

In speeches and testimonies, Alan Greenspan claimed intellectual links between his financial policies and the ideas of Milton Friedman and Joseph A. Schumpeter on banks, central banks, and financial crises. As the financial crisis deepened in 2008, Greenspan admitted that his policies had been shockingly wrong. The purpose of this paper is to explain why his claims of intellectual links between those policies and the ideas of Friedman and Schumpeter were also wrong.

Design/methodology/approach

Beginning with representative examples of Greenspan's citations of Friedman and of Schumpeter as supporting his financial policies, the authors review the economic ideas of Friedman and Schumpeter on banks, central banks, and financial crises. In each case, we contrast Greenspan's financial policies with those ideas, demonstrating the spurious nature of his claims of intellectual links.

Findings

While expanding the role of the Federal Reserve in the financial markets, Greenspan's financial policies were based on the declaration that deregulation and financial innovations were providing flexibility and stability for the entire financial system. In his financial policies, Greenspan rejected Friedman's recommendations for changes in the powers and functioning of the Federal Reserve that featured a monetary policy rule and the 100 percent reserve requirement for deposits that would involve the separation of depository banking from loans and investments. From a Schumpeterian perspective, Greenspan's policies encouraged and facilitated the massive “reckless” finance that was responsible for the financial crisis of 2007‐2009.

Originality/value

Greenspan's legacy as Chairman of the Federal Reserve Board is one of policies that first contributed to recurring financial crises of increasing severity and were then followed by an extraordinary policy expansion of the Federal Reserve in attempts to cope with the crises. On that basis, it is important to have a clear understanding of the lack of intellectual support for those policies from the influential economists with whom he claimed intellectual links.
Issues in mobile learning technology
Authors: Little Bob
Published: April 2013

Purpose

This paper aims to outline some key issues in mobile learning technology.

Design/methodology/approach

The paper discusses the impact of mobile learning technology, based on the author's experience in the field.

Findings

Decide, design, develop and deploy is the standard four‐step process relating to technology. The drivers for adopting new technologies in learning include not only the suppliers and the customers (the buyers) but also the consumers (users) – in other words, everyone. Increasingly – since about 2006 – consumers want to use mobile devices for learning and for the less formal “performance support”. Initially, there can a high cost of ownership (of the latest mobile devices). So the key issue for HR and learning & development (L&D) professionals is how to get the maximum value from, and use of, this technology.

Originality/value

The paper outlines key issues in mobile learning technology facing HR and L&D professionals, in particular how to get the maximum value from, and use of, this technology.
New technologies and performance support
Authors: Coulson‐Thomas Colin
Published: April 2013

Purpose

This paper aims to discuss the impact new technology has had on performance support.

Design/methodology/approach

The paper reports the findings from a five‐year investigation into methods of improving performance in the workplace.

Findings

HR applications of performance support offer significant advantages over general initiatives, e‐learning and face‐to‐face approaches to training and mentoring. Creating a shared understanding of HR and other policies, procedures and rules can present particular problems, particularly in diversified organizations when components have different histories and practices.

Originality/value

This article draws upon the findings of an investigation, which examined widely adopted approaches to improving performance with a view to identifying the most cost‐effective options. The investigation suggests “new management” is needed, requiring a shift of emphasis from top‐down direction and motivation to the provision of bottom‐up support.
Putting personalisation and integration into practice in primary care
Authors: Clark Michael , Moreland Neil , Greaves Ian , Greaves Nicola , Jolley David
Published: April 2013

Purpose

The purpose of this article is to discuss the policy developments of integration and personalisation within the context of Primary Care, specifically an innovative Memory Service provided within a General Practice. It examines how these policies work together in this context to deliver a high quality service that is responsive to individual needs in an area of care: memory disorder or dementia, which has often relied heavily on secondary care services.

Design/methodology/approach

The article is a case study analysis of integration and personalisation in Primary Care, allowing for examination and elaboration of both concepts as applied in this setting; and their contribution to a better quality care Memory Service. The analysis is produced by independent researchers (MC and NM), background and facts by service personnel (IG, NG and DJ).

Findings

The innovative Memory Service operates as a person‐centred facility, integrating into the surgery, expertise that would traditionally be locked into secondary care health services. It makes maximum use of locally available knowledge of the patient, their family and formal and informal sources of support and therapy through links which cross agency boundaries. These links are identified and utilised in tailored support for individuals by the practice‐based Dementia Advisor. Outcomes include improved dynamics of identification, diagnosis and after care, high satisfaction amongst patients and families and reduced utilisation and expenditure of other healthcare facilities.

Practical implications

Personalisation and integration can be united in the development of innovative and improved Memory Services centred in Primary Care.

Social implications

Maintaining a focus on the needs of people within their social contexts (being person‐centred) is a powerful means of driving better integrated care in Primary Care for people living with dementia and related disorders.

Originality/value

This is the first examination of personalisation and integration as coupled concepts to lead the improvement of care, specifically a Memory Service, in Primary Care.
Public‐private partnerships versus traditional procurement: Innovation incentives and information gathering
Authors: Hoppe Eva I. , Schmitz Patrick W.
Published: April 2013

A government agency wants a facility to be built and managed to provide a public service. Two different modes of provision are considered. In a public‐private partnership, the tasks of building and managing are bundled, whereas under traditional procurement, these tasks are delegated to separate private contractors. The two provision modes differ in their incentives to innovate and to gather private information about future costs to adapt the service provision to changing circumstances. The government agency’s preferred mode of provision depends on the information‐gathering costs, the costs of innovation efforts, and the degree to which effort is contractible.
Targeted advertising and advertising avoidance
Authors: Johnson Justin P.
Published: April 2013

I examine how the increasing ability of firms to target their ads influences market outcomes when consumers have access to advertising‐avoidance tools. Although firms generally benefit from improved targeting, consumers need not. I also show that there may be too little blocking of ads in equilibrium and consider the role of targeted advertising when niche firms compete against mass‐market firms.