bluuebunny/crossref_metadata_2025_split huggingface dataset:
Screening of promoters from rhizosphere metagenomic DNA using a promoter‐trap vector and flow cytometric cell sorting
Authors: Lee Se Hee , Kim Jeong Myeong , Lee Hyo Jung , Jeon Che Ok 
Published: January 2011

AbstractWe constructed a facilitative and efficient promoter‐trap vector, pCM‐EGFP, for capturing and analyzing functional promoters from environmental DNA. The pCM‐EGFP vector showed good chloramphenicol sensitivity and no enhanced green fluorescent protein (EGFP) gene expression. Promoter libraries were constructed for screening promoters responding to naringenin, a key molecule released from plant roots. After electroporation, E. coli transformants were incubated in LB broth containing chloramphenicol (10 μg/ml) to select against transformants with no cloned promoter. E. coli cells were sorted using flow cytometry without naringenin, and then sorted again with high fluorescence after incubation in LB broth with naringenin (1 mM) at 28 °C for 12 h. The inducible properties of approximately 400 sorted cells were evaluated, with most cells showing only strong EGFP gene expression without inducible properties. Two clones (5‐4E and 15‐3D) displayed naringenin inducibility, and both contained a promoter bounded by a TetR‐family regulator. The regulator knock‐out mutant of the 5‐4E clone lost its ability to be induced by naringenin. In conclusion, the pCM‐EGFP vector may be used as an efficient promoter‐trap vector and a combination of the vector with flow cytometric cell sorting was demonstrated to be an useful method for screening promoters responding to specific conditions or inducers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of polar impurities in biodiesels using solid‐phase extraction and gas chromatography–mass spectrometry
Authors: Yang Zeyu , Hollebone Bruce P. , Wang Zhendi , Yang Chun , Landriault Mike 
Published: January 2011

AbstractThis paper reports on a method for development and validation for simultaneous characterization and determination of oxygenated polar impurities – free fatty carboxylic acids (FFAs), partial glycerides (monoacylglycerides, MGs), residual glycerol and free sterols – in various biodiesels based on the combination of solid‐phase extraction (SPE), silylation and GC/MS technologies. The effects of various SPE and silylation conditions on the method recoveries were evaluated. Using this integrated SPE‐GC/MS method, 38 target polar compounds (13 FFAs, 17 glycerides and 8 sterols) in 9 biodiesels derived from 4 different feedstocks were successfully separated and quantified. It was found that the carbon chain length of FFAs was ranged from C6 to C24, with C16 and C18 being the most abundant in all biodiesels. The total FFAs concentration was consistent with the acid values (AVs) measured by standard method ASTM D974‐04. MG congeners with carbon number of 18 (mono‐C18) were most abundant in the biodiesel samples, followed by mono‐C16 and free glycerol. β‐Sitosterol and campesterol were found to be the prevailing phytosterols in all pure vegetable oil‐based biodiesels, while brassicasterol and stigmasterol was only significant in the biodiesel from canola oil and soybean oil, respectively, and abundant cholesterol was only detected in animal fat‐based biodiesels.
Exploring the elution mechanism of selenium species on liquid chromatography
Authors: Tsopelas Fotios , Tsantili‐Kakoulidou Anna , Ochsenkühn‐Petropoulou Maria 
Published: January 2011

AbstractIn the present work, the chromatographic behavior of eight selenium species, namely selenites (Se(IV)), selenates (Se(VI)), seleno‐DL‐methionine (Se‐Met), selenocystine (Se‐Cyst), selenocystamine (Se‐CM), selenourea (Se‐U), dimethylselenide ((CH3)2Se) and dimethyldiselenide ((CH3)2Se2), was investigated under different stationary and mobile phase conditions, in an effort to unravel secondary interferences in their underlying elution mechanism. For this purpose, two end‐capped and a polar‐embedded reversed‐phase stationary phases were employed using different mobile phase conditions. Retention factors (log kw) were compared with octanol–water distribution coefficients (log D) as well as with log kw values on two immobilized artificial membrane (IAM) columns and two immobilized artificial plasma proteins stationary phases, obtained in our previous work. The role of electrostatic interactions was confirmed by introducing the net charge of the investigated Se species as an additional term in the log kw/log D interrelation, which in most cases proved to be statistically significant. Principal component analysis of retention factors on all stationary phases and octanol–water log D values, however, showed that the elution of the investigated selenium species is mainly governed by partitioning mechanism under all different chromatographic conditions, while the pH of the mobile phase and the special column characteristics have only a minor effect.
Application of indicator systems for monitoring and assessment of desertification from national to global scales
Authors: Sommer S. , Zucca C. , Grainger A. , Cherlet M. , Zougmore R. , Sokona Y. , Hill J. , Della Peruta R. , Roehrig J. , Wang G. 
Published: January 2011

AbstractThis paper suggests how the United Nations Convention to Combat Desertification (UNCCD) community can progressively make use of a flexible framework of analytical approaches that have been recently developed by scientific research. This allows a standardized but flexible use of indicator sets adapted to specific objectives or desertification issues relevant for implementing the Convention. Science has made progress in understanding major issues and proximate causes of dryland degradation such that indicator sets can be accordingly selected from the wealth of existing and documented indicator systems. The selection and combination should be guided according to transparent criteria given by existing indicator frameworks adapted to desertification conceptual frameworks such as the Dryland Development Paradigm and can act as a pragmatic entry point for selecting area‐ and theme‐specific sets of indicators from existing databases. Working on different dryland sub‐types through a meaningful stratification is proposed to delimit and characterize affected areas beyond the national level. Such stratification could be achieved by combining existing land use information with additional biophysical and socio‐economic data sets, allowing indicator‐based monitoring and assessment to be embedded in a framework of specific dryland degradation issues and their impacts on key ecosystem services. Copyright © 2011 John Wiley & Sons, Ltd.
Q‐switched and modelocked all‐fiber lasers based on advanced acousto‐optic devices
Authors: Cuadrado‐Laborde C. , Díez A. , Cruz J.L. , Andrés M.V. 
Published: January 2011

AbstractThe interest in all‐fiber lasers is stimulated by the inherent advantages they have over bulk lasers in aspects such as heat dissipation and robustness. The performance of Q‐switched and modelocked fiber lasers can benefit enormously from the development of all‐fiber configurations. A fiber laser with strictly all‐fiber components can fulfil the requirements of mechanical stability, low maintenance, enhanced power efficiency, simplified assembly process, and low cost. In this framework, recent developments infiber acousto‐optic devices are reviewed that have demonstrated new possibilities for actively Q‐switched distributed feedback fiber lasers, modelocking lasers and doubly active Q‐switched modelocked lasers. The aim is to demonstrate the great potential of infiber devices for the active control of different types of fiber lasers.
Competition Between Viscoelasticity and Surfactant Dynamics in Flow Focusing Microfluidics
Authors: Lee Wingki , Walker Lynn M. , Anna Shelley L. 
Published: January 2011

AbstractThe goal of this work is to quantify the impact of viscoelasticity on a tipstreaming phenomenon observed in flow focusing microfluidic devices. Tipstreaming, or thread formation, is a phenomenon caused by surfactant transport to, from, and along, deforming interfaces that leads to long filaments in microfluidic devices. Viscoelasticity also leads to stable filaments, so possible synergies are investigated here. The ability to generate extremely long and thin filaments that will break up via interfacial instabilities will lead to the formation of droplets much smaller than the device lengthscales. Viscoelastic Boger fluids are used as the dispersed phase liquid in a flow focusing device and surfactant is added to the continuous phase liquid. We find a region of operating space in which viscoelasticity appears to couple with surfactant transport to form long threads. The phenomenon is described qualitatively and is related to fluid relaxation times. magnified image
A Dual Colorimetric and Fluorometric Sensor for Lead Ion Based on Conjugated Polydiacetylenes
Authors: Lee Kyung Mi , Chen Xiaoqiang , Fang Wang , Kim Jong‐Man , Yoon Juyoung 
Published: January 2011

AbstractA PDA based sensor, derived from a di‐(2‐picolyl) amine (DPA) substituted diacetylene monomer, displayed a selective colorimetric change and a large fluorescence enhancement in the presence of lead ions. The lead selective PDA‐based chemosensor enabled easy detection of the presence of lead in 100% aqueous solution by the naked‐eye. magnified image
RAFT Mediated Polymerization of Methyl Methacrylate Initiated by Bergman Cyclization: Access to High Molecular Weight Narrow Polydispersity Polymers
Authors: Gerstel Peter , Barner‐Kowollik Christopher 
Published: January 2011

AbstractThe first RAFT mediated polymerization of methyl methacrylate initiated by diradicals derived from Bergman cyclization was performed employing 3,4‐benzocyclodec‐3‐ene‐1,5‐diyne (BCDY) as diradical source and cyanoisopropyldithiobenzoate (CPDB) as RAFT agent. The polymerization was conducted in bulk at 80 °C for 3 h. The concentration of the enediyne was kept constant at 3.0 × 10−2 mol · L−1 and the RAFT agent concentration was varied between 0.0 mol · L−1 and 2.4 × 10−1 mol · L−1. A detailed ESI‐MS analysis reveals the absence of intramolecular termination reactions (ring formation) in the RAFT mediated system, which usually makes diradicalic initiation unfavorable. The presence of polymeric chains propagating at both ends could be confirmed. The conversion of the RAFT mediated polymerization was up to more than two times higher than the RAFT free polymerization at identical conditions. Thus, polymers with narrow polydispersities (1.1 ≤ PDI ≤ 1.5) even at very high molecular weights (near 400 000 Da) were obtained within modest reaction times. magnified image
High Performance Phototransistors of a Planar Conjugated Copolymer
Authors: Dong Huanli , Bo Zhishan , Hu Wenping 
Published: January 2011

AbstractA planar conjugated copolymer named HXS‐1 was applied in thin film phototransistors. Similar to organic field‐effect transistors using VG to control the source‐drain current, in phototransistors, the light is used to substitute VG as an independent variable to control the output of the transistors to realize light detection and signal magnification in a single organic device. All devices exhibited high performance with an on/off ratio up to 4.6 × 104 (the highest on/off ratio of organic or polymer phototransistors), which could be assigned to i) the wide absorption features of HXS‐1 in the whole UV‐vis range, ii) the ideal HOMO energy level of HXS‐1 (5.21 eV) to align with Au electrodes (5.2 eV) and iii) the high mobility of the polymer thin films (∼0.06 cm2/Vs). Moreover, the devices, both under continuous operation conditions and long term measurement conditions, exhibited excellent stability, indicating potential applications of the devices in polymer‐based optoelectronics. magnified image
Family‐based and population‐based association studies validate PTPRD as a risk factor for restless legs syndrome
Authors: Yang Qinbo , Li Lin , Yang Rong , Shen Gong‐Qing , Chen Qiuyun , Foldvary‐Schaefer Nancy , Ondo William G. , Wang Qing Kenneth 
Published: January 2011

AbstractObjective:We previously mapped a genetic locus for restless legs syndrome (RLS) to chromosome 9p22‐24 (RLS3) and a later genome‐wide association study (GWAS) implicated the PTPRD gene at the RLS3 locus as a susceptibility gene for RLS. However, from the standpoint of genetics, the GWAS association needs to be validated by independent studies. In this study, we used both family‐based and population‐based association studies to assess the association between PTPRD and RLS in an American Caucasian population.Methods:We genotyped two intronic SNPs rs1975197 and rs4626664 in PTPRD in 144 family members from 15 families and a case control cohort of 189 patients and 560 controls. Direct DNA sequence analysis was used to screen coding exons and exon‐intron boundaries of PTPRD for rare mutations.Results:A family‐based sibling transmission disequilibrium test showed association of RLS with SNP rs1975197 (P = 0.015), but not with rs4626664 (P = 0.622). The association with rs1975197 was significantly replicated by a population‐based case control association study (allelic P = 0.0004, odds ratio = 1.68; genotypic P = 0.0013 and 0.0003 for an additive and dominant model, respectively). One rare p.E1639D variant was identified in exon 39 in kindred RLS40005. The rare D1639 allele did not co‐segregate with RLS in the family, suggesting that p.E1639D variant is not a causative mutation.Conclusions:This represents the first independent study to validate the association between PTPRD variants and RLS. Both family‐based and population‐based association studies suggest that PTPRD variant rs1975197 confers risk of RLS. © 2011 Movement Disorder Society
The impact of non‐motor symptoms on health‐related quality of life of patients with Parkinson's disease
Authors: Martinez‐Martin Pablo , Rodriguez‐Blazquez Carmen , Kurtis Monica M. , Chaudhuri K. Ray ,   on Behalf of the NMSS Validation Group
Published: January 2011

AbstractBackground:Non‐motor symptoms are detrimental to health‐related quality of life (HRQoL) of Parkinson's disease patients. In this study, the Non‐Motor Symptoms Scale (NMSS) was used to assess the impact of the non‐motor symptoms on HRQoL of Parkinson's disease patients.Methods:In a multicenter, international, cross sectional study on 411 Parkinson's disease patients, the NMSS was applied along with clinical (Hoehn and Yahr staging and SCOPA‐Motor) and HRQoL measures (PDQ‐39, and EQ‐5D). Prevalence of non‐motor symptoms was determined also through the NMSS. The association of NMSS and SCOPA‐Motor with HRQoL measures and the differences in HRQoL scores between patients with and without non‐motor symptoms in each NMSS domain were estimated by non‐parametric statistics. Predictors of HRQoL were sought through multiple linear regression analyses.Results:Nocturia (68.4% of the sample), fatigue (65.9%), and dribbling saliva (56.7%), were the most frequent complaints. Total NMSS score: (1) showed a higher correlation coefficient (rS= 0.70) with the PDQ‐39 Summary Index (SI) than SCOPA‐Motor (rS= 0.58); (2) showed high‐moderate correlation (rS= 0.60 − 0.38) with all PDQ‐39 domains; and (3) was the best predictor of HRQoL as measured by the PDQ‐39 SI. For each NMSS domain, patients with symptoms had significantly worse HRQoL scores than patients without symptoms.Discussion:To our knowledge, this is the first study to determine in a holistic manner the impact of the non‐motor symptoms on HRQoL of Parkinson's disease patients. The results show that non‐motor symptoms have, as a whole, a greater impact on HRQoL than motor symptoms and non‐motor symptoms progression contributes importantly to HRQoL decline in patients with Parkinson's disease. © 2011 Movement Disorder Society
Akinetic‐rigid and tremor‐dominant Parkinson's disease patients show different patterns of FP‐CIT Single photon emission computed tomography
Authors: Eggers Carsten , Kahraman Deniz , Fink Gereon R. , Schmidt Matthias , Timmermann Lars 
Published: January 2011

AbstractObjective:To elucidate whether Parkinson's disease subtypes show a different pattern of Iodine‐123 fluoropropyl–;carbomethoxy‐3 β‐(FP‐CIT) single photon emission computed tomography (SPECT) binding in accordance with neuropathological findings.Methods:We analyzed a database of consecutive patients with FP‐CIT scan (n = 190) over a 3‐year period and identified 122 patients (50 women, 72 men, mean age 62 ± 11.1 years) with a diagnosis of idiopathic Parkinson's disease. Patient's characteristics and FP‐CIT scan results were analyzed and compared for the subgroups tremor‐dominant versus akinetic‐rigid and equivalent type of Parkinson's disease.Results:The analysis of all Parkinson's disease patients showed a significant difference between the FP‐CIT uptake in the subgroups tremor‐dominant and akinetic‐rigid. After matching these samples for age, disease duration, disease severity (Hoehn & Yahr grade, Unified Parkinson's Disease Rating Scale score), and levodopa‐equivalent dose, these findings were balanced between both groups (n = 23/23) without a significant difference (P > 0.05). However, there was a clear, significant association of visually analyzed shapes of the striatum in FP‐CIT SPECT and clinical Parkinson's disease subtype.Conclusion:These results confirm neuropathological models for a reduced dopaminergic projection to the dorsal putamen in akinetic‐rigid patients as well as the lateral putamen and caudate nucleus in tremor‐dominant patients in vivo. © 2011 Movement Disorder Society
The risk of valvular regurgitation in patients with Parkinson's disease treated with dopamine receptor agonists
Authors: Rasmussen Vibeke Guldbrand , Østergaard Karen , Dupont Erik , Poulsen Steen Hvitfeldt 
Published: January 2011

AbstractObjectives:Several observational studies suggest an association between treatment with ergoline‐derived dopamine agonists and valvular regurgitation. In this article, we present an overview of the literature and conduct a meta‐analysis.Methods:Observational studies addressing the frequency of moderate or severe valvular regurgitation among ergoline‐treated patients with Parkinson's disease were considered for a meta‐analysis. Pooled risk estimates and the risk of increased pulmonary artery pressure were calculated.Results:The pooling of data from well‐designed observational studies documented that both pergolide (RR = 3.05 [1.71–5.44]) and cabergoline (RR = 6.38 [3.17–12.81]) represent a substantially increased risk of developing moderate to severe valvular regurgitation. In addition, pergolide, but not cabergoline, was associated with an increase in pulmonary artery pressure.Conclusions:The present meta‐analysis confirmed a statistically significant association between pergolide and cabergoline treatment and the risk of moderate to severe valvular regurgitation. An association between bromocriptine and valvular regurgitation cannot be entirely ruled out. © 2011 Movement Disorder Society
Chemoinformatics as a Theoretical Chemistry Discipline
Authors: Varnek Alexandre , Baskin Igor I. 
Published: January 2011

AbstractHere, chemoinformatics is considered as a theoretical chemistry discipline complementary to quantum chemistry and force‐field molecular modeling. These three fields are compared with respect to molecular representation, inference mechanisms, basic concepts and application areas. A chemical space, a fundamental concept of chemoinformatics, is considered with respect to complex relations between chemical objects (graphs or descriptor vectors). Statistical Learning Theory, one of the main mathematical approaches in structure‐property modeling, is briefly reviewed. Links between chemoinformatics and its “sister” fields – machine learning, chemometrics and bioinformatics are discussed.
A 3‐node flat triangular shell element with corner drilling freedoms and transverse shear correction
Authors: Zhang Yun , Zhou Huamin , Li Jianhui , Feng Wei , Li Dequn 
Published: January 2011

AbstractThe formulation, implementation and testing of simple, efficient and robust shell finite elements have challenged investigators over the past four decades. A new 3‐node flat triangular shell element is developed by combination of a membrane component and a plate bending component. The ANDES‐based membrane component includes rotational degrees of freedom, and the refined nonconforming element method‐based bending component involves a transverse shear correction. Numerical examples are carried out for benchmark tests. The results show that compared with some popular shell elements, the present one is simple but exhibits excellent all‐around properties (for both membrane‐and bending‐dominated situations), such as free of aspect ratio locking, passing the patch test, free of shear locking, good convergence and high suitability for thin to moderately thick plates. The developed element has already been adopted in a warpage simulation package for injection molding. Copyright © 2011 John Wiley & Sons, Ltd.
A spectral element approach for the stability of delay systems
Authors: Khasawneh Firas A. , Mann Brian P. 
Published: January 2011

AbstractWe describe a spectral element approach to study the stability and equilibria solutions of Delay differential equations (DDEs). In contrast to the prototypical temporal finite element analysis (TFEA), the described spectral element approach admits spectral rates of convergence and allows exploiting hp‐convergence schemes. The described approach also avoids the limitations of analytical integrations in TFEA by using highly accurate numerical quadratures—enabling the study of more complicated DDEs. The effectiveness of this new approach is compared with well‐established methods in the literature using various case studies. Specifically, the stability results are compared with the conventional TFEA and Legendre collocation methods whereas the equilibria solutions are compared with the numerical simulations and the homotopy perturbation method (HPM) solutions. Our results reveal that the presented approach can have higher rates of convergence than both collocation methods and the HPM. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of organoclay loading and electron beam irradiation on the physico‐mechanical properties of low‐density polyethylene/ethylene‐vinyl acetate blend
Authors: Shojaei A. , Behradfar A. , Sheikh N. 
Published: January 2011

AbstractThe influence of electron beam (EB) irradiation and organoclay (OC) loading on the properties of low‐density polyethylene (LDPE)/ethylene‐vinyl acetate (EVA) blends was investigated. The samples were subjected to the EB irradiation with the dose values of 50 and 250 kGy. X‐ray diffraction (XRD), gel content, mechanical, thermal, and electrical properties were utilized to analyze the characteristics of the LDPE/EVA blends with and without OC at different irradiation dosages. Gel content analysis showed that the OC promotes considerably the insoluble part so that the LDPE/EVA blends filled with OC become fully crosslinked at 250 kGy; possibly through the formation of further crosslinks between OC and polymer chains. The samples irradiated by EB showed enhanced mechanical properties due to the formation of three‐dimensional networks. In addition, thermogravimetric analysis indicated that combined OC loading and radiation‐induced crosslinking improved thermal stability of LDPE/EVA blends considerably. Copyright © 2011 John Wiley & Sons, Ltd.