bluuebunny/crossref_metadata_2025_split huggingface dataset:
Speciation Analysis of Thallium by Reversed‐phase Liquid Chromatography ‐ Inductively Coupled Plasma Mass Spectrometry
Authors: Chu Yun‐Ling , Wang Ruoh‐Yun , Jiang Shiuh‐Jen 
Published: January 2012

AbstractAn inductively coupled plasma mass spectrometer (ICP‐MS) was used as a liquid chromatographic detector for the speciation analysis of thallium in environmental samples. In this study, ionic thallium species, namely Tl(I) and Tl(III) were well separated by reversed‐phase high performance liquid chromatography (RP‐HPLC) with a C8‐HPLC column as the stationary phase and 1 mmol L−1 tetrabutylammonium phosphate (TBAP), 2 mmol L−1 diethylenetriamine pentaacetic acid (DTPA) in 1% v/v methanol solution (pH 6) as the mobile phase. Effluent from the HPLC column was delivered to the nebulizer of the ICP‐MS for the determination of thallium. The separation was complete in less than 3 min. Detection limit was 0.002 μg L−1 for both Tl(I) and Tl(III) compounds based on peak height. The relative standard deviation of the peak areas for five injections of a mixture containing 1 μg Tl L−1 was better than 3.4%. The concentrations of Tl compounds were determined in standard reference materials, including NIST SRM 1643e Trace Elements in Water and NRCC NASS‐5 Open Ocean Seawater and water samples collected in Kaohsiung area, Taiwan. The HPLC‐ICP‐MS results of the reference samples agreed with the reference values. This method has also been applied to determine Tl(I) and Tl(III) compounds in custard apple (Annona squamosa) leaves collected from Chai‐shan Mountain, Kaohsiung and Taitung City, Taiwan. The thallium species were quantitatively leached from the leaves with a 5 mmol L−1 DTPA in 100 mmol L−1 ammonium acetate solution in an ultrasonic bath during a period of 30 min. The HPLC‐ICP‐MS result that was obtained after the analysis of leaves sample showed a satisfactory agreement with the total thallium concentration obtained by ICP‐MS analysis of completely dissolved sample.
A Modified Synthesis of Some Novel Polycyclic Aromatic Phenazines and Quinoxalines by Using the Tungstate Sulfuric Acid (TSA) as a Reusable Catalyst under Solvent‐free Conditions
Authors: Karami Bahador , Khodabakhshi Saeed , Nikrooz Marzieh 
Published: January 2012

AbstractConsidering the synthesis of new compounds, we developed heterocyclic chemistry. We also helped to improve the classical synthetic route for the synthesis of quinoxalines and phenazines through implement in terms of solvent‐free reaction. For the condensation of 1,2‐dicarbonyls and o‐phenylenediamines under solvent‐free conditions at room temperature, tungstate sulfuric acid (TSA) was found to be an efficient and reusable reagent. The high yield of the pure products and simple preparation of the catalyst have allowed the synthesis of several phenazines and quinoxalines using this methodology.
Movement disorders: role of imaging in diagnosis
Authors: Mascalchi Mario , Vella Alessandra , Ceravolo Roberto 
Published: January 2012

AbstractMagnetic resonance imaging (MRI and single‐photon emission computed tomography (SPECT) have a considerable role in the diagnosis of the single patient with movement disorders. Conventional MRI demonstrates symptomatic causes of parkinsonism but does not show any specific finding in Parkinson's disease (PD). However, SPECT using tracers of the dopamine transporter (DAT) demonstrates an asymmetric decrease of the uptake in the putamen and caudate from the earliest clinical stages. In other degenerative forms of parkinsonism, including progressive supranuclear palsy (PSP), multisystem atrophy (MSA), and corticobasal degeneration (CBD), MRI reveals characteristic patterns of regional atrophy combined with signal changes or microstructural changes in the basal ganglia, pons, middle and superior cerebellar peduncles, and cerebral subcortical white matter. SPECT demonstrates a decreased uptake of tracers of the dopamine D2 receptors in the striata of patients with PSP and MSA, which is not observed in early PD. MRI also significantly contributes to the diagnosis of some inherited hyperkinetic conditions including neurodegeneration with brain iron accumulation and fragile‐X tremor/ataxia syndrome by revealing characteristic symmetric signal changes in the basal ganglia and middle cerebellar peduncles, respectively. A combination of the clinical features with MRI and SPECT is recommended for optimization of the diagnostic algorithm in movement disorders. J. Magn. Reson. Imaging 2012 © 2012 Wiley Periodicals, Inc.
The fatty acid and tocopherol constituents of the seed oil extracted from 21 grape varieties (Vitis spp.)
Authors: Sabir Ali , Unver Ahmet , Kara Zeki 
Published: January 2012

AbstractBACKGROUND: Fatty acids and tocopherols in appropriate quantities are invaluable attributes that are desirable in seeds of agricultural products. Studies have generally focused on the evaluation of the oil and tocopherol components of oil crops. Recently, investigations revealed that the grape seed has robust potential in the production of healthy fatty acids as well as tocopherols. This study was thus conducted to determine the oil and tocopherol components of grape seeds, obtained from various grape cultivars of different species, including two rootstock varieties.RESULTS: The grape seed oil concentration of the studied varieties ranged from 7.3 to 22.4%. The determined fatty acid profiles of the genotypes conformed to the pattern described in the literature for grapes. Linoleic acid is the major component comprising 53.6–69.6% of the total, followed by oleic (16.2–31.2%), palmitic (6.9–12.9%) and stearic (1.44–4.69%). The oils of all the seeds analysed showed a preponderance of α‐tocopherol (ranging from 260.5 to 153.1 mg kg−1 oil extract). β‐Tocopherol, γ‐tocopherol and δ‐tocopherol were also detected with the general means of 0.98, 22.2 and 0.92 mg kg−1, respectively. Linoleic acid showed a significantly negative correlation with all the fatty acids analysed. The strongest negative correlation existed between linoleic and oleic acids (r = − 0.834, P < 0.01).CONCLUSION: Present investigations indicated that oil content, fatty acid composition and tocopherol constituents of grape seed show great variation among the genotypes. Markedly higher proportions of linoleic acid with considerable amounts of tocopherols found in the oil samples suggest that grape seed is a good source for culinary, pharmaceutical and cosmetic uses. Copyright © 2012 Society of Chemical Industry
Isolation and characterisation of lactic acid bacteria from jiang‐gua (fermented cucumbers), a traditional fermented food in Taiwan
Authors: Chen Yi‐sheng , Wu Hui‐chung , Lo Huei‐yin , Lin Wan‐chen , Hsu Wen‐hsuan , Lin Ching‐wen , Lin Po‐ya , Yanagida Fujitoshi 
Published: January 2012

AbstractBACKGROUND: Jiang‐gua (fermented cucumbers) is a popular traditional fermented food in Taiwan. The microflora of lactic acid bacteria (LAB) in jiang‐gua have not been investigated in detail. In this study, LAB from jiang‐gua were isolated, characterised and identified.RESULTS: A total of 103 LAB were isolated; 70 cultures were isolated from jiang‐gua samples and 33 cultures were isolated from its raw substrate, cucumber. These isolates were mainly characterised phenotypically and then divided into seven groups (A‐G) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. The isolates were identified as Enterococcus casseliflavus, Leuconostoc lactis, Leuconostoc mesenteroides, Lactobacillus pentosus, Lactobacillus plantarum, Lactobacillus paraplantarum, Lactococcus lactis subsp. lactis, Weissella cibaria and Weissella hellenica. The antibacterial activities of the isolates were determined and 11 Lc. lactis subsp. lactis strains showed inhibitory activity against the indicator strain Lactobacillus sakei JCM 1157T.CONCLUSION: Heterofermentative W. cibaria and Leu. lactis were the major LAB found in jiang‐gua samples without soy sauce. In soy sauce‐added samples, homofermentative L. pentosus and L. plantarum were the most abundant LAB. In addition, the results also suggested that HhaI and RsaI restriction enzymes could be applied to distinguish W. hellenica and Weissella paramesenteroides. Copyright © 2012 Society of Chemical Industry
Risk of advanced fibrosis with grafts from hepatitis C antibody–positive donors: A multicenter cohort study
Authors: Lai Jennifer C. , O'Leary Jacqueline G. , Trotter James F. , Verna Elizabeth C. , Brown Robert S. , Stravitz Todd R. , Duman Jeffrey D. , Forman Lisa M. , Terrault Norah A. 
Published: January 2012

Abstract
Over the last decade, the use of liver grafts from hepatitis C virus antibody–positive donors [HCV(+)Ds] has tripled in the United States. Although previous studies have demonstrated no association between an HCV(+)D status and graft loss, the effects of an HCV(+)D on histological outcomes are not well known. Hepatitis C virus (HCV)–infected recipients at 5 US centers (2002-2007) who survived more than 30 days with 1 or more posttransplant biopsy samples were included. Cox regression was used to examine the association between an HCV(+)D status and advanced fibrosis (stage 3/4 or higher). Ninety-nine of the 1206 patients (8%) received an HCV(+)D graft. Recipients of HCV(+)D grafts were older than recipients of hepatitis C virus antibody–negative donor [HCV(−)D] grafts (P = 0.03), but they were otherwise similar. HCV(+)D grafts were significantly lower in quality according to the donor risk index (P < 0.001). Advanced fibrosis occurred in 32% of HCV(+)D graft recipients and in 28% of HCV(−)D graft recipients (P = 0.39). The unadjusted 1- and 3-year rates of advanced fibrosis were significantly higher for HCV(+)D graft recipients (14% and 48%) versus HCV(−)D graft recipients (7% and 33%, P = 0.01). Transplantation with HCV(+)D grafts was associated with a 58% increased risk of advanced fibrosis [95% confidence interval (CI) = 1.05-2.36, P = 0.03]. However, in an analysis stratified by the mean donor age of 45 years, an HCV(+)D status was associated with advanced fibrosis only with donors >45 years old [hazard ratio (HR) = 1.76, 95% CI = 1.06-2.93, P = 0.03] and not with donors ≤45 years old (HR = 0.94, 95% CI = 0.47-1.87, P = 0.85). In conclusion, a careful consideration of the risks and benefits is needed with HCV(+)D grafts. Recipients of HCV(+)D grafts (especially from older donors) should undergo close monitoring for more rapidly progressive fibrosis. Studies are needed to determine whether early HCV therapy modifies this risk. Liver Transpl, 2012. © 2012 AASLD.
Influence of damage on pore size distribution and permeability of rocks
Authors: Arson Chloé , Pereira Jean‐Michel 
Published: January 2012

SUMMARYThe model proposed in this article relates permeability to porosity measurements that can easily be performed in the laboratory. The pore size distribution (PSD) curve is updated with strains and damage. The updated volumetric fractions of natural pores and cracks are introduced in the expression of permeability. Contrary to classical permeability models based on PSD integrations, the model proposed in this article accounts for possible changes in the porosity modes: one mode for undamaged samples and two modes for cracked samples. The proposed approach also accounts for varying states of damage, as opposed to classical fracture network models, in which the cracks pattern is fixed. The only material parameters that are required to describe the microstructure are the lower and upper bounds of the pores size for both natural pores and cracks. All the other PSD parameters involved in the model are related to macroscopic parameters that can easily be determined in the laboratory, such as the initial void ratio. The framework proposed in this article can be used in any damage constitutive model to determine the permeability of a brittle porous medium. Drained triaxial compression tests have been simulated. Before cracks initiation, permeability decreases while the larger natural pores are getting squeezed. After the occurrence of damage, permeability grows due to the increase of cracks density. The model performs well to represent the influence of the confining pressure on damage evolution and permeability variations. Copyright © 2012 John Wiley & Sons, Ltd.
A mobility model for studying wireless communication and the complexity of problems in the model
Authors: Greenlaw Raymond , Kantabutra Sanpawat , Longani Pattama 
Published: January 2012

AbstractWireless communication has become omnipresent in the world and enables users to have an unprecedented ability to communicate any time and any place. In this article, we propose a mobility model for studying wireless communication. The model incorporates elements such as users, access points, and obstacles so that it faithfully mimics the real environment. Interesting problems that have practical applications are posed and solved. More specifically, we study the complexity of three problems in a grid. The source reachability problem (SRP) models a situation in which we want to determine whether two access points can communicate at a certain time in a mobile environment. When users are involved in this situation, we call this problem the user communication problem (UCP). We show that SRP can be solved in O(max{d,t}m2) time, where d is the number of obstacles, t is the time bound in the statement of the problem, and m is the number of access points; we show that UCP can be solved in O(max{d,t}m4) time. The third problem called the user communication, limited source access problem (UCLSAP) studies a situation where we want to determine whether two users can communicate uninterruptedly during the duration of the model while considering battery‐time limits of the access points. In contrast to the first two problems, we demonstrate that UCLSAP is intractable, unless P = NP. In conclusion, we briefly discuss the extension of our model to three dimensions and provide a list of open problems. © 2012 Wiley Periodicals, Inc. NETWORKS, 2012
Deterministic rendezvous in networks: A comprehensive survey
Authors: Pelc Andrzej 
Published: January 2012

AbstractTwo or more mobile entities, called agents or robots, starting at distinct initial positions, have to meet. This task is known in the literature as rendezvous. Among many alternative assumptions that have been used to study the rendezvous problem, two most significantly influence the methodology appropriate for its solution. The first of these assumptions concerns the environment in which the mobile entities navigate: it can be either a terrain in the plane, or a network modeled as an undirected graph. The second assumption concerns the way in which the entities move: it can be either deterministic or randomized. In this article, we survey results on deterministic rendezvous in networks. © 2012 Wiley Periodicals, Inc. NETWORKS, 2012
Velocity and range of fragments from accidental explosions
Authors: Dostal L. , Janovsky B. , Ferjencik M. 
Published: January 2012

AbstractA method for determining the initial velocity and range of flying fragments is proposed. Quantity‐Distance (Q‐D) principles are discussed and some arguments are presented for why even the observance of Q‐D principles cannot prevent sympathetic explosions due to flying fragments. Example calculations are included and the results are compared to the results of an actual explosion. The results show that this method should be suitable for evaluating fragment velocity and range. Limitations of the method and proposals for possible future improvements are discussed in the conclusions. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012
Isolation and expression of genes for acetolactate synthase and acetyl‐CoA carboxylase in Echinochloa phyllopogon, a polyploid weed species
Authors: Iwakami Satoshi , Uchino Akira , Watanabe Hiroaki , Yamasue Yuji , Inamura Tatsuya 
Published: January 2012

AbstractBACKGROUND: Target‐site resistance is the major cause of herbicide resistance to acetolactate synthase (ALS)‐ and acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicides in arable weeds, whereas non‐target‐site resistance is rarely reported. In the Echinochloa phyllopogon biotypes resistant to these herbicides, target‐site resistance has not been reported, and non‐target‐site resistance is assumed to be the basis for resistance. To explore why target‐site resistance had not occurred, the target‐site genes for these herbicides were isolated from E. phyllopogon, and their expression levels in a resistant biotype were determined.RESULTS: Two complete ALS genes and the carboxyltransferase domain of four ACCase genes were isolated. The expression levels of ALS and ACCase genes were higher in organs containing metabolically active meristems, except for ACC4, which was not expressed in any organ. The differential expression among examined organs was more prominent for ALS2 and ACC2 and less evident for ALS1, ACC1 and ACC3.CONCLUSION: E. phyllopogon has multiple copies of the ALS and ACCase genes, and different expression patterns were observed among the copies. The existence of three active ACCase genes and the difference in their relative expression levels could influence the occurrence of target‐site resistance to ACCase inhibitors in E. phyllopogon. Copyright © 2012 Society of Chemical Industry
Affect of film thickness on the blue photoluminescence from ZnO
Authors: Moore J. C. , Covington L. R. , Stansell R. 
Published: January 2012

AbstractWe have investigated the photoluminescence (PL) properties of ZnO grown on sapphire substrates via the thermal oxidation of Zn‐metal films at various temperatures and having various thicknesses. PL spectra indicate four emission bands: excitonic ultraviolet (UV), blue, and deep‐level green and yellow emission. The ratio of deep‐level green emission to UV excitonic emission was observed to decrease with decreasing annealing temperature from 1200 to 300 °C, which is attributed to the generation of fewer oxygen vacancies (${\rm V}_{{\rm O}}^{ + } $) and interstitial oxygen ions (${\rm O}_{{\rm i}}^{- } $) in the bulk. As film thickness decreased from approximately 600 to 200 nm, we observed the emergence of blue emission and a significant red shift (0.15 eV) in the bandgap. The emergence of blue emission and the corresponding decrease in emission associated with bulk defects when depletion width grows relative to the bulk suggests that the origin of the blue emission is related to the charged zinc interstitials (${\rm V}_{{\rm Zn}}^{- } $) found within the deletion region near the interface.
Atomic‐ and molecular‐scale devices and systems for single‐molecule electronics
Authors: Prauzner‐Bechcicki Jakub S. , Godlewski Szymon , Szymonski Marek 
Published: January 2012

AbstractPresent‐day electronic technology, based to a large extent on silicon fabricated devices, is surely approaching size limitations arising from quantum effects. The effort to achieve rapid development of electronic devices requires implementation of entirely new ideas that will allow existing technological constraints to be overcome. Among a wide range of concepts, utilization of single organic molecules, acting as active blocks performing logic operations, appears as one of the most appealing and is based on the state‐of‐the‐art use of modern nanotechnology. In this short review, we offer a selection of recent experiments addressing milestones of single‐molecule computing devices technology. Along with discussion of the latest achievements in atomic‐ and molecular‐scale technologies, we discuss their future perspectives, challenges, and still unsolved issues standing in the way of practical implementation of single‐molecule devices. magnified imageConcept of a single‐molecule electronic device. The molecule is equipped with various functional groups responsible for logic operations and bonding to an underlying surface and metallic nanoelectrodes. The monomolecular nanodevice is deposited on a thin buffer layer assuring the decoupling from a (semi‐)conducting substrate.
Enhanced performance in inverted organic light emitting diode assisted by an interlayer of crystalline and n‐doped 1,4,5,8‐naphthalene‐tetracarboxylic‐dianhydride
Authors: Qin Dashan , Chen Lei , Chen Yuhuan , Liu Jinsuo , Li Guifang , Quan Wei , Zhang Jidong , Yan Donghang 
Published: January 2012

AbstractInverted bottom‐emission organic light emitting diodes (IBOLEDs) employing the electron injection structure of indium tin oxide (ITO)/1,4,5,8‐naphthalene‐tetracarboxylic‐dianhydride (NTCDA)/Li2CO3 doped bathocuproine (BCP) (1:4 Li2CO3:BCP) were fabricated, where NTCDA and BCP stand for NTCDA and BCP, respectively. The NTCDA on ITO was characterized crystalline and n‐doped as a result of the interaction between ITO and NTCDA. Compared to the IBOLED using the electron injection structure of ITO/10 nm 1:4 Li2CO3:BCP, the one utilizing the electron injection structure of ITO/3 nm NTCDA/7 nm 1:4 Li2CO3:BCP showed the remarkable increases in both current density and efficiency, mainly due to the higher electron conductivity of n‐doped NTCDA than that of n‐doped BCP. The dependence of the current conduction in IBOLED on the thickness of NTCDA was investigated. We provide a simple method to significantly enhance the performance of IBOLEDs.
Well‐ordered arrays of ferroelectric single‐crystalline BaTiO3 nanostructures
Authors: Chen Di , Zhang Haitao , Chen Rike , Deng Xiangyun , Li Jianbao , Zhang Guoqing , Wang Liming 
Published: January 2012

AbstractHighly ordered arrays of BaTiO3 nanostructures were synthesized by the hydrothermal method using TiO2 nanotube arrays as templates. The synthesis yields apparent preferred orientation nanostructures with a perovskite structure. The pristine nanostructures are high purity and contain some degree of hydroxyl group or absorbed oxygen. Ferroelectric domains are present at the nanostructures, and typical hysteresis loops with remanent polarization and coercive field are 8.93 µC cm2 and 53 kV/cm, respectively.
Large‐scale interventions in science education for diverse student groups in varied educational settings
Authors: Lee Okhee , Krajcik Joseph 
Published: January 2012

AbstractCurrent classroom practices in the U.S. and internationally have largely been shaped by changing student demographics and accountability policies. This special issue includes manuscripts that develop conceptual frameworks or report on empirical studies addressing large‐scale interventions of educational innovations for diverse student groups in varied educational settings. Understanding issues related to large‐scale interventions will be particularly important for the U.S. as the science education system embraces new science standards [National Research Council, [2011] A framework for K‐12 science education: Practices, crosscutting concepts, and core ideas. Washington, DC: National Research Council.]. In our introduction to the special issue, we discuss critical issues in scaling up educational innovations through which large‐scale interventions evolve. First, we describe the process of scaling up an educational innovation. Then, we address challenges in scaling up an innovation. Next, we discuss implications that these challenges present to implementation of an innovation and evaluation of its efficacy and effectiveness. Finally, we briefly introduce the articles that appear in this special issue. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 271–280, 2012
Overactive bladder in men: initial assessment
Authors: Birch Andrew , Dowson Christopher , Seth Jai , Khan Mohammad Shamim , Dasgupta Prokar , Sahai Arun 
Published: January 2012

AbstractIn the first of a two‐part series, the authors provide an overview of the prevalence and impact of overactive bladder, and give advice on frontline investigation and how and when to refer. Part 2 will cover the goals and strategies of therapy. Copyright © 2012 John Wiley & Sons