bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing Planning and Set‐Shifting Abilities in Autism: Are Experimenter‐Administered and Computerised Versions of Tasks Equivalent?
Authors: Williams David , Jarrold Christopher
Published: July 2013

Across studies, analysis of performance on classic measures of executive functioning (EF) among individuals with autism spectrum disorder (ASD) suggests that people with this disorder may be impaired only when tasks are experimenter‐administered, but not when the same tasks are computer‐administered. This would imply that the underlying cause of apparent executive dysfunction in ASD is a diminished ability to engage with another person/comprehend what another person expects, rather than a diminution of the control processes that typically underpin EF task performance. However, this suggestion is limited because, to our knowledge, no study has directly compared the equivalence of computer‐administered and standard experimenter‐administered versions of EF tasks that have been presented in counterbalanced order among a common sample of individuals with ASD. In the current study, 21 children with ASD and 22 age‐ and intelligence quotient (IQ)‐matched comparison participants completed, in counterbalanced order, computerised and manual versions of both a planning task and a cognitive flexibility/set‐shifting task. Contrary to expectation, results indicated that participants with ASD were equally impaired in terms of the key dependent variable on standard and computerised versions of both tasks. Practically, these results suggest that computer‐administered and experimenter‐administered versions of planning and set‐shifting tasks are equivalent among individuals with ASD and can be used interchangeably in studies of EF among this population. Theoretically, these results challenge the notion that poor performance on EF tasks among school‐aged children with ASD is only the result of a limited ability to engage with a human experimenter/comprehend socially presented rules. Autism Res 2013, 6: 461–647. © 2013 International Society for Autism Research, Wiley Periodicals, Inc.
Cyclotides as grafting frameworks for protein engineering and drug design applications
Authors: Poth Aaron G. , Chan Lai Y. , Craik David J.
Published: July 2013

Cyclotides are a family of naturally occurring backbone‐cyclized macrocyclic mini‐proteins from plants that have a knotted trio of intramolecular disulfide bonds. Their structural features imbue cyclotides with extraordinary stability against degradation at elevated temperatures or in the presence of proteolytic enzymes. The plasticity of their intracysteine loop sequences is exemplified by the more than 250 natural cyclotides sequenced to date, and this tolerance to sequence variation, along with their diverse bioactivities, underpins the suitability of the cyclic cystine knot motif as a valuable drug design scaffold and research tool for protein engineering studies. Here, we review the recent literature on applications of cyclotides for the stabilization of peptide epitopes and related protein engineering studies. Possible future directions in this field are also described. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 480–491, 2013.
Recombinant expression of backbone‐cyclized polypeptides
Authors: Borra Radhika , Camarero Julio A.
Published: July 2013

Here we review the different biochemical approaches available for the expression of backbone‐cyclized polypeptides, including peptides and proteins. These methods allow for the production of circular polypeptides either in vitro or in vivo using standard recombinant DNA expression techniques. Polypeptide circularization provides a valuable tool to study the effects of topology on protein stability and folding kinetics. Furthermore, having biosynthetic access to backbone‐cyclized polypeptides makes the production of genetically encoded libraries of cyclic polypeptides possible. The production of such libraries, which was previously restricted to the domain of synthetic chemistry, now offers biologists access to highly diverse and stable molecular libraries that can be screened using high‐throughput methods for the rapid selection of novel cyclic polypeptide sequences with new biological activities. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 502–509, 2013.
An Enantiospecific Polyene Cyclization Initiated by an Enantiomerically Pure Bromonium Ion
Authors: Braddock D. Christopher , Marklew Jared S. , Foote Kevin M. , White Andrew J. P.
Published: July 2013

Dimethylaluminum triflate‐mediated activation of tetrafluorobenzoates of enantiomerically pure bromohydrins results in enantiospecific polyene cyclizations. The initiation of cyclization by enantiomerically pure bromonium ions and subsequent propagation is not subject to catastrophic erosion of enantiomeric purity by any intramolecular or intermolecular bromonium ion‐to‐alkene transfer. Chirality 25:692–700, 2013. © 2013 Wiley Periodicals, Inc.
Comparative HPLC Enantioseparation of Thirty‐Six Aromatic Compounds on Four Columns of the Lux® Series: Impact of Substituents, Shapes and Electronic Properties
Authors: Peluso Paola , Cossu Sergio
Published: July 2013

With the aim to define a combined computational/chromatographic empirical approach useful for the high‐performance liquid chromatography (HPLC) method development of new chiral compounds, 36 racemic aromatic compounds with different chemical structures were used as test probes on four polysaccharide‐based chiral stationary phases (CSPs) of the Lux series, namely Lux Cellulose‐1, Lux Cellulose‐2, Lux Cellulose‐4, and Lux Amylose‐2, using classical n‐hexane/2‐propanol mixtures as mobile phase. Electrostatic potential surfaces (EPSs) determined using Density Functional Theory (DFT) calculations were used to derive size, shape, and electronic properties of each analyte. Then a comparative HPLC screening was carried out in order to evaluate the impact of substituents, shapes, and electronic properties of the analytes on the chromatographic behavior as the column changes. The four CSPs showed good complementary recognition ability. The elution sequence was determined in 30 cases out of 36. The success rate to afford baseline separations (Rs ≥ 1.5) was estimated: 29 compounds out of 36 showed baseline enantioseparation on at least one of the four selected CSPs. The combined computational‐chromatographic screening furnished useful collective structure‐chromatographic behavior relationships and a map of the chiral discrimination abilities of the considered CSPs towards the analytes. On this basis, the chromatographic behavior of new analytes on a set of polysaccharide‐based CSPs can be mapped through the qualitative correlation of chromatographic parameters (k, α, Rs) to computed molecular properties of the analytes. Chirality 25:709–718, 2013. © 2013 Wiley Periodicals, Inc.
Study on Lithium Insertion in Lepidocrocite and λ‐MnO2 Type TiO2: A First‐Principles Prediction
Authors: Liu Yahui , Wu Jingyi , Zhao Wei , Chu Jinglong , Qi Tao
Published: July 2013

TiO2 is a latent anode material for rechargeable lithium batteries. Our simulation models, basing lepidocrocite and λ‐MnO2 type TiO2, were investigated by density functional theory (DFT). The key issues are focused on the lithium insertion sites, electronic structures, and the conducting paths of Li+ ions. Our calculated data indicate the calculated voltage of λ‐MnO2 type TiO2 is higher than that of lepidocrocite type TiO2. The Li+ ion migration energy barrier of lepidocrocite type TiO2 along the [1 0 0] direction (0.45 eV) is lower than that of along the [1 1 0] direction (0.57 eV). The energy barriers of λ‐MnO2 type TiO2 to move a Li+ ion among the adjacent embedded sites (16c or 8a sites) is 0.68 eV.
Preparation of Monodispersed Copper Nanoparticles by an Environmentally Friendly Chemical Reduction
Authors: Li Meijuan , Xiang Kun , Luo Guoqiang , Gong Daoren , Shen Qiang , Zhang Lianmeng
Published: July 2013

In this paper, highly dispersive nanosized copper particles with a mean particle size of less than 6 nm are prepared by an environmentally friendly chemical reduction method. Non‐toxic L‐ascorbic acid acts as both reducing agent and antioxidant in ethylene glycol in the absence of any other capping agent. Transmission electron microscopy (TEM) is used to characterize the size and morphology of Cu nanoparticles. The results of UV‐Vis spectroscopy (UV‐Vis), energy dispersive spectroscopy (EDS) and high resolution TEM (HRTEM) illustrate that the resultant product is pure Cu nanocrystals. The size of Cu nanoparticles is remarkably impacted by the order of reagent addition, and the investigation reveals the reaction procedure of Cu2+ ions and L‐ascorbic acid.
Cu(I)‐Catalyzed Synthesis of 2‐Substituted Benzimidazoles from 2‐Iodoanilines and Amides
Authors: Yuan Hua , Chen Yongxin , Song Jinli , Chen Chunxia , Chen Baohua
Published: July 2013

A novel and efficient approach to the synthesis of 2‐substituted benzimidazoles has been developed via CuI/DMEDA‐catalyzed coupling reaction and post‐cyclization with glacial acetic acid from readily available 2‐iodoanilines and amides. This method is suitable for the construction of a variety of benzimidazoles in moderate to good yields under short reaction times.
Asymmetric Synthesis, Antifungal Activity and Molecular Modeling of Iodiconazole Isomers
Authors: Zhang Yongqiang , Wang Shengzheng , Miao Zhenyuan , Yao Jianzhong , Zhang Wannian , Sheng Chunquan
Published: July 2013

Iodiconazole is a novel antifungal agent that was developed in its racemic form. In order to investigate the effects of the chiral center on the antifungal activity, R‐ and S‐isomers of iodiconazole were prepared on the basis of the asymmetric Sharpless epoxidation. (S)‐Iodiconazole was proved to have better antifungal activity than the (R)‐isomer. The binding modes of the two isomers with lanosterol 14α‐demethylase were clarified by molecular docking.
New training tools for new epidemiologists
Authors: Arts Ilja C.W. , Weijenberg Matty P.
Published: July 2013

Molecular epidemiology is moving from an era of single marker studies to omics‐driven population‐based studies, made possible by recent rapid technological advances in high‐throughput laboratory assays. The use of these assays in large, observational, epidemiologic studies poses major methodological challenges. The traditional, reductionist approach that most epidemiologists have been taught is no longer sufficient with the introduction of omics data into epidemiology. However, basic epidemiological principles, such as confounding, must still be addressed. In order to successfully implement these tools into molecular epidemiology, scientists in the required disciplines must be able to effectively communicate. We propose an interdisciplinary, three‐level, problem‐based approach to training in molecular epidemiology. This approach requires interdisciplinary teaching teams that appeal to students coming from diverse backgrounds. First, concepts from each field necessary for molecular epidemiology must be addressed at a basic level, with a specific focus on biological, epidemiological, and statistical concepts. Second, state‐of the art methods applied in molecular epidemiology should be covered (e.g., omics technologies, smart study designs, statistical modeling, and biological interpretation). Third, the application of omics technologies in population studies calls for awareness of issues related to biobanking, ethics, legislation, and public health. Problem‐based learning is a useful tool for teaching when students need to apply complex concepts to complex situations as is the case in molecular epidemiology. Using this approach, students from diverse backgrounds work together to analyze problems, discuss, and exchange knowledge in modern molecular epidemiology. Training tools characterized by this approach will shape the molecular epidemiologists of the future. Environ. Mol. Mutagen. 54:611‐615, 2013. © 2013 Wiley Periodicals, Inc.
Backward‐in‐Time Selection of the Order of Dynamic Regression Prediction Model
Authors: Vlachos Ioannis , Kugiumtzis Dimitris
Published: July 2013

We investigate the optimal structure of dynamic regression models used in multivariate time series prediction and propose a scheme to form the lagged variable structure called Backward‐in‐Time Selection (BTS), which takes into account feedback and multicollinearity, often present in multivariate time series. We compare BTS to other known methods, also in conjunction with regularization techniques used for the estimation of model parameters, namely principal components, partial least squares and ridge regression estimation. The predictive efficiency of the different models is assessed by means of Monte Carlo simulations for different settings of feedback and multicollinearity. The results show that BTS has consistently good prediction performance, while other popular methods have varying and often inferior performance. The prediction performance of BTS was also found the best when tested on human electroencephalograms of an epileptic seizure, and for the prediction of returns of indices of world financial markets.Copyright © 2013 John Wiley & Sons, Ltd.
Performance of the Direct Methanol Carbonate Fuel Cell Using Anion Exchange Materials and Non‐Noble Metal Cathode Catalyst
Authors: Wang X. , Yu E. H. , Horsfall J. , Scott K.
Published: July 2013

A direct methanol fuel cell using a mixture of O2 and CO2 at the cathode was evaluated using anion exchange materials and cathode catalysts of Pt and a non‐Pt catalyst. The MEA based on non‐noble metal catalyst Acta 4020 showed superior performance than Pt/C based MEA in terms of open circuit potential and power density in carbonate environment. The fuel cell performance was improved by applying anion exchange ionomer in the catalyst layer. A maximum power density of 4.5 mW cm–2 was achieved at 50 °C using 6.0 M methanol and 2.0 M K2CO3.
Analysis of EMIC‐wave‐moderated flux limitation of measured energetic ion spectra in multispecies magnetospheric plasmas
Authors: Mauk B. H.
Published: July 2013

A differential Kennel‐Petschek (KP) flux limit for magnetospheric energetic ions is devised taking into account multiple ion species effects on electromagnetic ion cyclotron (EMIC) waves that scatter the ions. The idea is that EMIC waves may limit the highest ion intensities during acceleration phases of storms and substorms (~ hour) while other mechanisms (e.g., charge exchange) may account for losses below those limits and over longer periods of time. This approach is applied to published Earth magnetosphere energetic ion spectra (~ keV to ~1 MeV) for radial positions (L) 3 to 6.7 RE. The flatness of the most intense spectral shapes for <100 keV indicate sculpting by just such a mechanism, but modifications of traditional KP parameters are needed to account for maximum fluxes up to 5.4 times greater than expected. Future work using the new capabilities of the Van Allen Probes mission will likely resolve outstanding uncertainties.
Toxicity of graphene nanoflakes evaluated by cell‐based electrochemical impedance biosensing
Authors: Yoon Ok Ja , Kim Insu , Sohn Il Yung , Kieu Truong Thuy , Lee Nae‐Eung
Published: July 2013

Graphene nanoflake toxicity was analyzed using cell‐based electrochemical impedance biosensing with interdigitated indium tin oxide (ITO) electrodes installed in a custom‐built mini‐ incubator positioned on an inverted optical microscope. Sensing with electrochemical measurements from interdigitated ITO electrodes was highly linear (R2 = 0.93 and 0.96 for anodic peak current (Ipa) and cathodic peak current (Ipc), respectively). Size‐dependent analysis of Graphene nanoflake toxicity was carried out in a mini‐incubator system with cultured HeLa cells treated with Graphene nanoflakes having an average size of 80 or 30 nm for one day. Biological assays of cell proliferation and viability complemented electrochemical impedance measurements. The increased toxicity of smaller Graphene nanoflakes (30 nm) as measured by electrochemical impedance sensing and optical monitoring of treated cells was consistent with the biological assay results. Cell‐based electrochemical impedance biosensing can be used to assess the toxicity of nanomaterials with different biomedical and environmental applications. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2288–2294, 2014.
Polyethyleneimine‐poly(ethylene glycol)‐star‐copolymers as efficient and biodegradable vectors for mammalian cell transfection
Authors: Ladewig Katharina , Xu Zhi Ping , Gray Peter , (Max) Lu G. Q.
Published: July 2013

High molecular weight (MW) polyethyleneimine (PEI) has been successfully used for the transfection of a broad variety of cell lines. In contrast to low MW PEI, which exhibits low transfection efficiencies but also low cytotoxicity, high MW PEI‐mediated transfection achieves much higher efficiencies but at the cost of cell viability; therefore its use in commercial scale transfection and clinical application is limited. In this work we address this problem by constructing biodegradable high MW PEI mimics built from low MW PEI building blocks. The end‐groups of small 5‐arm star polyethylene glycol (PEG) prepolymers were decorated with linear oligo‐ethyleneimine (OEI)/PEI arms of various MW via azomethine linkages. The resultant PEI‐PEG‐star‐copolymers were investigated for their ability to complex plasmid DNA. Polymer/DNA complexes were characterized using techniques such as dynamic light scattering and transmission electron microscopy. Having established their cytotoxicity limits, they were tested as gene delivery vehicles for the transfection of suspension adapted Chinese hamster ovary (CHO‐S) cells under serum‐free conditions and adherent human embryonic kidney cells (HEK293T) in serum containing medium. Our PEI‐PEG‐star‐copolymers showed a reduced cytotoxicity compared to high MW PEI while maintaining the ability to complex plasmid DNA and transfect mammalian cells, with significant transfection efficiencies. The effects of the optimum parameters on the transfection of mammalian cells using such novel polymers are discussed. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2137–2146, 2014.
Interaction between mesenchymal stem cells and Ti‐30Ta alloy after surface treatment
Authors: Capellato Patricia , Escada Ana L. A. , Popat Ketul C. , Claro Ana P. R. Alves
Published: July 2013

In this study, in vitro cytocompatibility was investigated in the Ti‐30Ta alloy after two kinds of surfaces treatments: alkaline and biomimetic treatment. Each condition was evaluated by scanning electron microscopy/energy‐dispersive X‐ray spectroscopy. Cellular adhesion, viability, protein expression, morphology, and differentiation were evaluated with Bone marrow stromal cells (MSCs) to investigate the short and long‐term cellular response by fluorescence microscope imaging and colorimetric assays techniques. Two treatments exhibited similar results with respect to total protein content and enzyme activity as compared with alloy without treatment. However, it was observed improved of the biomineralization, bone matrix formation, enzyme activity, and MSCs functionality after biomimetic treatment. These results indicate that the biomimetic surface treatment has a high potential for enhanced osseointegration. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2147–2156, 2014.
Effects of DS‐modified agarose gels on neurite extension in 3D scaffold through mechanisms other than changing the pore radius of the gels
Authors: Peng Jin , Pan Qian , Zhang Wei , Yang Hao , Zhou Xue , Jiang Hua
Published: July 2013

Dermatan sulfate is widely distributed as glycosaminoglycan side chains of proteoglycans, which are the main components of glial scar and inhibit neurite regeneration after nerve injury. However its role in the inhibiting process is not clear. Understanding neurite extension in three‐dimensional scaffolds is critical for neural tissue engineering. This study used agarose gels modified with dermatan sulfate as the three‐dimensional culture scaffold. We explored structure–function relationship between the three‐dimensional scaffold and neurite extension and examined the role of dermatan sulfate on neurite extension in the three‐dimensional scaffold. A range of agarose concentrations was used to generate varied gel physical structures and the corresponding neurite extension of embryonic day (E9) chick dorsal root ganglia was examined. We measured gel stiffness and gel pore size to determine whether dermatan sulfate changed the gels' conformation. As gel concentration increased, neurite length and gel pore size decreased, and gel stiffness increased. At 1.00 and 1.25% (wt/vol) concentrations, dermatan sulfates both immobilized with agarose gels and dissolved in culture medium inhibit neurite extension. While at 1.50 and 1.75% (wt/vol) concentrations, only immobilized dermatan sulfate worked. Immobilized dermatan sulfate could modify molecular shape of agarose gels, decrease gel pore size statistically, but did not influence gel stiffness. We have proved that the decrease of gel pore size is insufficient to inhibit neurite extension. These results indicate that dermatan sulfate inhibits neurite extension not through forming a mechanical barrier. Maybe its interaction with neuron membrane is the key factor in neurite extension. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2157–2162, 2014.
One‐Pot Synthesis of CdSe Quantum Dots in Aqueous Solution for Biological Labeling
Authors: Dong Meiting , Fu Shasha , Liu Shuxian , Xu Jingyi , Huang Chaobiao
Published: July 2013

The one‐pot synthesis of water‐soluble and biologically compatible yellow CdSe quantum dots (QDs) featuring the use of glutathione (GSH) as the capping and reducing agent was achieved under aqueous conditions at 150 °C. The synthesized yellow CdSe QDs with quantum yield (QY) up to 20% exhibit zinc blende cubic structure particles with an average diameter of 4‐5 nm. It was found that both molar ratio of Se/Cd and reaction time had a significant effect on size distribution of GSH‐CdSe QDs. Meanwhile, the interaction of QDs bioconjugated to bovine hemoglobin (BHb) was studied by absorption and fluorescence(FL) spectra. With addition of BHb, the FL intensity of CdSe QDs largely quenched due to the static mechanism. The linear range is 5.0 × 10−8 mol/L to 3.0 × 10−6 mol/L, and the correlation coefficient is 0.9991, suggesting that could be used as a probe to label biological molecules and bacterial cells.
Spatial and diurnal variability in reactive nitrogen oxide chemistry as reflected in the isotopic composition of atmospheric nitrate: Results from the CalNex 2010 field study
Authors: Vicars W. C. , Morin S. , Savarino J. , Wagner N. L. , Erbland J. , Vince E. , Martins J. M. F. , Lerner B. M. , Quinn P. K. , Coffman D. J. , Williams E. J. , Brown S. S.
Published: July 2013

Here we present measurements of the size‐resolved concentration and isotopic composition of atmospheric nitrate (NO3−) collected during a cruise in coastal California. Significant differences in air mass origin and atmospheric chemistry were observed in the two main regions of this cruise (South and Central Coast) with corresponding differences in NO3− concentration and isotope ratios. Measurements of the 17O‐excess (Δ17O) of NO3− suggest that nocturnal chemistry played an important role in terms of total NO3− production (~ 50%) in the coastal Los Angeles region (South Coast), where NO3− concentrations were elevated due to the influence of sea breeze / land breeze recirculation and Δ17O(NO3−) averaged (25.3 ± 1.6)‰. Conversely, Δ17O(NO3−) averaged (22.3 ± 1.8)‰ in the Central Coast region, suggesting that the daytime OH + NO2 reaction was responsible for 60–85% of NO3− production in the marine air sampled in this area. A strong diurnal signal was observed for both the Δ17O and δ15N of NO3−. In the case of Δ17O, this trend is interpreted quantitatively in terms of the relative proportions of daytime and nighttime production and the atmospheric lifetime of NO3−. For δ15N, which had an average value of (0.0 ± 3.2)‰, the observed diurnality suggests a combined effect of isotopic exchange between gas‐phase precursors and variability in reactive nitrogen sources. These findings represent a significant advance in our understanding of the isotope dynamics of nitrate and its precursor molecules, with potentially important implications for air quality modeling.
Long‐term survival after hepatic and pulmonary resection of colorectal cancer metastases
Authors: Sourrouille Isabelle , Mordant Pierre , Maggiori Léon , Dokmak Safi , Lesèche Guy , Panis Yves , Belghiti Jacques , Castier Yves
Published: July 2013

Background

Recent changes in adjuvant therapies improved the prognosis of metastatic colorectal cancers. Curative resection may be considered, even for both pulmonary and hepatic metastases, but prognostic factors are not well identified.

Methods

From 1995 to 2010, 69 patients had curative resection of pulmonary metastases of colorectal cancer; 31 had also hepatic metastases. Pulmonary and hepatic resection occurred in 2 steps (87%). We studied overall and disease‐free survival and prognostic factors.

Results

Primary tumor location was the rectum in 10 cases (32%). Pulmonary metastases were synchronous in 5 (16%) and bilateral in 6 (19%). One patient (3%) died after pulmonary surgery. One (3%) had positive surgical margins for pulmonary metastases. Median overall survival was 44 months (5‐year rate = 36%); median disease‐free survival was 22 months (5‐year rate = 10%). Factors linked to impaired survival were rectal primary tumor (P = 0.04) and bilateral pulmonary metastases (P = 0.02) for overall survival, and pulmonary metastase≥20 mm (P = 0.04) for disease‐free survival.

Conclusion

When associated to adjuvant therapy, complete resection of pulmonary and hepatic metastases of colorectal cancer allows long‐term survival in one third of the patients. J. Surg. Oncol. 2013 108:220–224. © 2013 Wiley Periodicals, Inc.
Fabrication methods of 3D periodic metallic nano/microstructures for photonics applications
Authors: Hossain Md Muntasir , Gu Min
Published: July 2013

Periodic metallic nano/microstructures have received a great a deal of attention in the photonics research community over the last few decades due to their intriguing optical properties. Three‐dimensional metallic nano/microstructures such as metallic photonic crystals, metamaterials, and plasmonic devices possess unique characteristics of tailored thermal radiation, negative refraction and deep subwavelength confinement of light. In this article, the recent progress on the experimental methods for the realisation of three‐dimensional periodic metallic and thin metal film coated dielectric nano/microstructures operating from optical to mid‐infrared frequencies has been reviewed. Advancement of the state‐of‐the‐art nanofabrication methods over the last few decades have led to the development of metallic nano/microstructures of diverse geometries, high resolution features and large scale production. The recent progress in the novel fabrication methods have inspired the development of functional and exciting photonic devices based on periodic metallic nano/microstructures with various applications in photonics including communications, photovoltaics, and biophotonics.
Dispersion of Silver Nanoparticles into Polymer Matrix Dry Adhesives to Achieve Antibacterial Properties, Increased Adhesion, and Optical Absorption
Authors: Bovero Enrico , Magee Kaylee E. A. , Young Edgar C. , Menon Carlo
Published: July 2013

The fabrication and characterization of dry adhesives treated with silver (Ag) nanoparticles presenting enhanced adhesion and antibacterial properties is described. A one‐step procedure for the dispersion of Ag nanoparticles in polydimethylsiloxane (PDMS) is implemented, achieving a uniform distribution of particles within the polymer with an average particle size of 40 nm. An order‐of‐magnitude increase in adhesion is observed for both flat and structured polymers treated with silver, in comparison with adhesives consisting of PDMS without silver. An average reduction of bacterial growth of 2 log‐units is observed upon exposure to Ag treated polymers in comparison to polymers without silver. This indicates the potential for employing this material in environments where avoidance of bacterial contamination is crucial.
Efficient Sustainable Tool for Monitoring Chemical Reactions and Structure Determination in Ionic Liquids by ESI‐MS
Authors: Khemchyan Levon L. , Khokhlova Elena A. , Seitkalieva Marina M. , Ananikov Valentine P.
Published: July 2013

An easy and convenient procedure is described for monitoring chemical reactions and characterization of compounds dissolved in ionic liquids using the well‐known tandem mass spectrometry (MS/MS) technique. Generation of wastes was avoided by utilizing an easy procedure for analysis of ionic liquid systems without preliminary isolation and purification. The described procedure also decreased the risk of plausible contamination and damage of the ESI‐MS hardware and increased sensitivity and accuracy of the measurements. ESI‐MS detection in MS/MS mode was shown to be efficient in ionic liquids systems for structural and mechanistic studies, which are rather difficult otherwise. The developed ESI‐MS/MS approach was applied to study samples corresponding to peptide systems in ionic liquids and to platform chemical directed biomass conversion in ionic liquids.
The Effects of Green Cards on the Wages and Innovations of New PhDs
Authors: Lan Xiaohuan
Published: July 2013

Visa policies in the United States restrict job opportunities and job mobility for U.S.‐trained PhDs who hold a temporary visa, a group that accounts for 40 percent of newly graduated PhDs in science and engineering. The Chinese Student Protection Act of 1992 (CSPA) allowed Chinese students to be eligible for permanent residence in the United States. Many CSPA beneficiaries, Chinese students who became permanent residents, did not pursue postdoctoral training and instead entered the public or private sector directly. This supply shift increased the relative wage of native postdocs to non‐postdocs. Four to eight years after graduation, CSPA beneficiaries earned 9 percent more than the comparison group, were less likely to work in academia, published fewer research articles, and produced more patents.
Transcriptional responses, metabolic activity and mouthpart deformities in natural populations of chironomus riparius larvae exposed to environmental pollutants
Authors: Planelló Rosario , Servia María J. , Gómez‐Sande Pablo , Herrero Óscar , Cobo Fernando , Morcillo Gloria
Published: July 2013

Biomarkers are an important tool in laboratory assays that link exposure or effect of specific toxicants to key molecular and cellular events, but they have not been widely used in invertebrate populations exposed to complex mixtures of environmental contaminants in their natural habitats. The present study focused on a battery of biomarkers and their comparative analysis in natural populations of the benthic larvae of Chironomus riparius (Diptera), sampled in three differentially polluted rivers (the Con, Sar, and Louro in Galicia, Spain). In our study, some parameters were identified, such as hsp70 gene activity, GST enzymatic activity, total glycogen content and mouthpart deformities, which showed significant differences among populations from the three rivers that differed in the levels and types of sedimentary contaminants analyzed (metals, organic‐chlorine pesticides, alkylphenols, pharmaceutical, and personal care products). In contrast to these sensitive biomarkers, other parameters showed no significant differences (hsc70 gene, EcR gene, P450 gene, RNA:DNA ratio, total protein content), and were stable even when comparing field and nonexposed laboratory populations. The hsp70 gene seems to be particularly sensitive to conditions of pollutant exposure, while its constitutive counterpart hsc70 showed invariable expression, suggesting that the hsc70/hsp70 ratio may be a potential indicator of polluted environments. Although further studies are required to understand the correlation between molecular responses and the ecological effects of pollutants on natural populations, the results provide new data about the biological responses to multiple‐stressor environments. This field study adds new molecular endpoints, including gene expression, as suitable tools that, complementing other ecotoxicological parameters, may help to improve the methodologies of freshwater monitoring under the increasing burden of xenobiotics. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 383–395, 2015.
Analysis of decision-making coefficients of three main fiber quality traits for upland cotton (Gossypium hirsutum L.)
Authors: Mei Yongjun , Hu Wenming , Fan Shuli , Song Meizhen , Pang Chaoyou , Yu Shuxun
Published: July 2013

The analysis of genetic correlations between fiber length (Len), strength (Str), micronaire, and 12 other traits was conducted using the additive (A)-dominance (D) genetic model, which considers genotype × environment interaction effects, in intraspecific upland cotton (Gossypium hirsutum L.) hybrids to effectively improve the quality of cotton cultivars in high planting density cases. Decision-making coefficients were computed based on the genetic correlation and path analysis of three fiber quality traits. The decision-making coefficient analysis of three fiber traits in cross breeding was beneficial for the improvement of Len by increasing the additive effects of Str and length of boll (LB) and decreasing lint percentage (LP), boll number of the top three fruit-bearing branches. The analysis was also beneficial for the improvement of Str and fiber fineness by increasing or decreasing the additive effects of other traits. Utilizing heterosis in hybrids was beneficial to the heterosis of Len by selecting the high dominance effects of number of nodes of the 1st fruit-bearing branch and LB and decreasing the dominance effects of diameter of boll (DB) and LP and for improving Str by increasing the dominance effects of DB and decreasing the dominance effects of number of fruit-bearing branches and number of nodes of the main stem (NNMS). Utilizing heterosis was also beneficial for improving fineness by increasing the dominance effects of LB, Str, and lint yield and decreasing the dominance effects of NNMS and Len.
TraceeElements in Leccinum scabrum mushrooms and topsoils from Kłodzka Dale in Sudety Mountains, Poland
Authors: Zhang Dan , Zhang Yu , Morawska Ewa , Bielawski Leszek , Krasińska Grażyna , Drewnowska Małgorzata , Pankavec Sviatlana , Szymańska Karolina , Falandysz Jerzy
Published: July 2013

In the current study, we determined concentrations and transfer rates of Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, P, Rb, Sr and Zn to Brown Birch Scaber Stalks (Leccinum scabrum) mushrooms emerged in the area of Sudety Mountains (Sudetes) in Poland. Fruiting bodies and topsoil samples beneath L. scabrum were collected form the Kłodzka Dale. The trace elements were determined using validated method and inductively coupled plasma — atomic emission spectroscopy (ICP-AES) for final measurement. Mushrooms contained Ag, Cr, Hg, Co, Ni and Sr at < 1.0 μg/g dry weight; Ba and Pb at ∼1.0 μg/g dw; Cd at < 5 μg/g dw; Cu and Mn at > 10 μg/g dw; Al and Ca at ∼100 μg/g dw; Fe, Na, Rb and Zn at 100 to 500 μg/g dw, Mg at ∼1,000 μg/g dw; P at ∼5,000 μg/g dw and K at ∼30,000 μg/g dw. Ca, Mn and Ni were nearly equally distributed between stipes and caps; stipes compared to caps were enriched in Ba, Na and Sr, while caps were enriched in Ag, Al, Cd, Co, Cr, Cu, Fe, K, P, Pb, Rb and Zn. The values of bioconcentration factor (BCF) varied highly depending on chemical element and were >1 for Ag, Cd, Cu, K, Mg, Na, P, Rb and Zn, while <1 for Al, Ba, Ca, Co, Cr, Fe, Mn, Ni, Pb and Sr. Topsoil showed elevated content of lead and mean concentration was 99 ± 32 μg/g dw, while cadmium was at 0.41 ± 0.15 and those two highly toxic to human elements occurred in edible caps of L. scabrum at 4.5 ± 2.2 and 2.9 ± 2.0 μg/g dw, respectively.
Relationships for maximum flame surface density and brush thickness through conditional analysis in turbulent premixed combustion
Authors: Huh Kang Y. , Kwon Jaesung , Lee Dongkyu
Published: July 2013

A new conditional averaging method is introduced in terms of the reaction progress variable, c, and its derivatives of successively higher orders, $\Sigma _f^{\prime} $Σf′ (or −∂c/∂n) and ∂2c/∂n2, in high Damköhler number (Da) turbulent premixed combustion. c is continuous and differentiable in space so that conditional averages may be defined for flamelets of finite thicknesses as well as for infinitesimally thin flamelets. A coupled set of transport equations are derived with corresponding conditional coefficient terms for mean reaction progress variable, $\bar c$c¯, and flame surface density (FSD), Σf. Statistics for all component terms are consistent with previous results and show the same qualitative trends irrespective of compressibility by the new averaging practice. It is shown that the maximum FSD, Σmax, occurs at the location where the relationship, $\nabla ^2 \bar c + \langle {\nabla \cdot {\bf n}} \rangle _f \Sigma _f = 0$∇2c¯+⟨∇·n⟩fΣf=0, holds in a flame brush. An analytical expression is derived for Σmax under the assumption of constant tangential strain rate and linear variation of mean curvature and mean displacement speed, ⟨Sd⟩f, in the $\bar c$c¯ space. Σmax becomes equal to one fourth ⟨|∇·n|⟩f or half the mean absolute curvature for fully turbulent flames with the magnitude of ⟨n⟩f close to zero. Once the turbulent burning velocity, ST, is determined by asymptotic behavior at the leading edge, the brush thickness, ℓF, may be obtained from local and integral relationships for the product, ℓFΣmax, in a steadily propagating one-dimensional flame. The newly proposed relationships reproduce proper trends of variation for ST, Σmax, and ℓF against measurement data in literature. They are validated to show good agreement with direct numerical simulation (DNS) results of the Lewis number equal to unity for freely propagating incompressible and stagnating compressible turbulent premixed flames.
Evolution of structure, dielectric properties, and re-entrant relaxor behavior in Ba5LaxSm1−xTi3Nb7O30 (x = 0.1, 0.25, 0.5) tungsten bronze ceramics
Authors: Li Kun , Li Zhu Xiao , Qiang Liu Xiao , Ming Chen Xiang
Published: July 2013

The effects of A site occupation on the structure, dielectric, and re-entrant relaxor behaviors were studied for Ba5LaxSm1−xTi3Nb7O30 (x = 0.1, 0.25, 0.5) tungsten bronze ceramics. The tetragonal tungsten bronze structure in space group P4bm was indicated for all compositions. The dielectric and ferroelectric properties were investigated over a broad temperature range. For all compositions, broad permittivity peaks with strong frequency dispersion were observed, where the peak points well fitted the Vogel-Fulcher relationship. The temperature dependency of ferroelectric hysteresis loops indicated the re-entrant relaxor behavior for all compositions: both the maximum and remanent polarization tended to decrease and vanish at low temperatures. In Ba5LaxSm1−xTi3Nb7O30, the re-entrant temperature (Tr) decreased with La-substitution, and the reduced remanent polarization at Tr (PTr) was determined. It seemed that the A1 site cation substitution exerted direct effects on the long-range ferroelectric order, and then the re-entrant relaxor behavior.
Voltage control of an isolated self-excited induction generator using static synchronous compensator
Authors: Benghanem M. , Bouzid A. M. , Bouhamida M. , Draou A.
Published: July 2013

Voltage fluctuations due to random load variation are amongst the most important power-quality problem in a self-excited induction generator (SEIG) and wind energy conversion system. This paper presents a comprehensive modeling analysis and control strategy of a three-phase cage induction machine used as a self-excited induction generator. The proposed load voltage control strategy is based on the action of the static synchronous Compensator (STATCOM) which can not only provide the necessary reactive power but also may enhance the load ability. Moreover, a feed forward control method for the STATCOM is introduced and applied for controlling the SEIG's terminal voltage by using an outer control loop. An inner loop was also used to control the STATCOM's output reactive power to achieve the regulation of the AC bus voltage during load variation. To achieve this objective, we have designed and introduced an RST inner loop controller. To demonstrate the effectiveness of the proposed RST controller, a comprehensive set of simulation results are presented and thoroughly discussed in comparison with those of two other classical controllers, namely, the proportional-integral controller and the integral-proportional controller.
High-speed impact test using an inertial mass and an optical interferometer
Authors: Jin T. , Watanabe K. , Prayogi I. A. , Takita A. , Mitatha S. , Djamal M. , Jia H. Z. , Hou W. M. , Fujii Y.
Published: July 2013

A high-speed impact testing method for evaluating mechanical properties of materials is proposed using an inertial mass and a dual beat-frequencies laser Doppler interferometer (DB-LDI). In this method, an inertial mass levitated using an aerostatic linear bearing is made to collide with the material being tested at a high initial velocity. During the collision, the velocity of the mass, which is even higher than the critical velocity (±0.56 m/s) defined by the frequency difference of the Zeeman laser, is accurately measured using the DB-LDI. The position, acceleration, and impact force of the mass are calculated from the measured velocity. Using the proposed method, the mechanical properties of a visco-elastic material under a high-speed impact loading condition can be accurately evaluated.
Quenching of the E2 phonon line in the Raman spectra of wurtzite GaAs nanowires caused by the dielectric polarization contrast
Authors: Ramsteiner M. , Brandt O. , Kusch P. , Breuer S. , Reich S. , Geelhaar L.
Published: July 2013

We investigate the Raman intensity of E2H phonons in wurtzite GaAs nanowire ensembles as well as single nanowires as a function of excitation wavelength. For nanowires with radii in the range of 25 nm, an almost complete quenching of the E2H phonon line is observed for excitation wavelengths larger than 600 nm. The observed behavior is quantitatively explained by the dielectric polarization contrast for the coupling of light into the GaAs nanowires. Our results define the limits of Raman spectroscopy for the detection of the wurtzite phase in semiconductor nanowires.
Prevalence and Risk Factors Associated with Vancomycin-Resistant Staphylococcus aureus Precursor Organism Colonization among Patients with Chronic Lower-Extremity Wounds in Southeastern Michigan
Authors: Tosh Pritish K. , Agolory Simon , Strong Bethany L. , VerLee Kerrie , Finks Jennie , Hayakawa Kayoko , Chopra Teena , Kaye Keith S. , Gilpin Nicholas , Carpenter Christopher F. , Haque Nadia Z. , Lamarato Lois E. , Zervos Marcus J. , Albrecht Valerie S. , McAllister Sigrid K. , Limbago Brandi , MacCannell Duncan R. , McDougal Linda K. , Kallen Alexander J. , Guh Alice Y.
Published: July 2013

Background.

Of the 13 US vancomycin-resistant Staphylococcus aureus (VRSA) cases, 8 were identified in southeastern Michigan, primarily in patients with chronic lower-extremity wounds. VRSA infections develop when the vanA gene from vancomycin-resistant enterococcus (VRE) transfers to S. aureus. Incl8-like plasmids in VRE and pSK41-like plasmids in S. aureus appear to be important precursors to this transfer.

Objective.

Identify the prevalence of VRSA precursor organisms.

Design.

Prospective cohort with embedded case-control study.

Participants.

Southeastern Michigan adults with chronic lower-extremity wounds.

Methods.

Adults presenting to 3 southeastern Michigan medical centers during the period February 15 through March 4, 2011, with chronic lower-extremity wounds had wound, nares, and perirectal swab specimens cultured for S. aureus and VRE, which were tested for pSK41-like and Incl8-like plasmids by polymerase chain reaction. We interviewed participants and reviewed clinical records. Risk factors for pSK41-positive S. aureus were assessed among all study participants (cohort analysis) and among only S. aureus-colonized participants (case-control analysis).

Results.

Of 179 participants with wound cultures, 26% were colonized with methicillin-susceptible S. aureus, 27% were colonized with methicillin-resistant S. aureus, and 4% were colonized with VRE, although only 17% consented to perirectal culture. Six participants (3%) had pSK41-positive S. aureus, and none had Incl8-positive VRE. Having chronic wounds for over 2 years was associated with pSK41-positive S. aureus colonization in both analyses.

Conclusions.

Colonization with VRSA precursor organisms was rare. Having long-standing chronic wounds was a risk factor for pSK41-positive S. aureus colonization. Additional investigation into the prevalence of VRSA precursors among a larger cohort of patients is warranted.
Pokes, Pathogens, and Primum Non Nocere: Prudent Prophylaxis Protocols for Prostate Biopsy
Authors: Drawz Sarah M. , Johnson James R.
Published: July 2013

Infectious complications following transrectal ultrasound-guided biopsy of the prostate (TRUBP)—including urinary tract infections, prostatitis, epididymo-orchitis, and bacteremia—have increased dramatically in recent years. Traditionally, fluoroquinolones have been the mainstay for perioperative prophylaxis. Likely as a result of a combination of this selective pressure and temporal shifts in the clonal composition of the rectal microbiota, most post-TRUBP infections today are caused by fluoroquinolone-resistant Escherichia coli, especially those from sequence type 131 (ST131), an emerging multidrug-resistant strain that is highly prevalent among pre-TRUBP rectal isolates. Clinicians need improved approaches for preventing these complications. Fortunately, helpful guidance is beginning to appear.
Development of a LAMP assay for rapid detection of different intimin variants of attaching and effacing microbial pathogens
Authors: Xue-han Zhang , Qing Ye , Ya-dong Liu , Bin Li , Renata Ivanek , Kong-wang He
Published: July 2013

Intimin harboured by pathogenic Escherichia coli (E. coli) strains is a key virulence factor involved in host cell adherence and colonization. Twenty-seven intimin-encoding E. coli attaching and effacing (eae) gene variants have been reported according to their 3′ binding domain sequences. In our study, we developed a specific and sensitive loop-mediated isothermal amplification (LAMP) assay to detect all known intimin variants. Four primers specific for six regions of eae genes were designed using online software. The eae-LAMP assay was highly specific and detected all 27 tested eae variants; no cross-reactions were observed with genes from enterotoxigenic E. coli (ETEC), E. coli BL21, Salmonella, Shigella, Listeria monocytogenes, or Streptococcus
suis type 2 (SS2). With the lowest detection limit of approximately 10 copies per reaction the eae-LAMP assay was 100 times more sensitive than conventional PCR. These results, and the results of tests involving food and faecal samples artificially contaminated with E. coli O157 : H7 (eaeγ+), show that the eae-LAMP assay is a simple, rapid, sensitive and specific tool for detecting intimin variants from pathogenic strains of E. coli. The eae-LAMP assay has great potential for wider applications, not only in the laboratory but also in the field setting, as it does not require specialized equipment.