bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of C18 silica and multi‐walled carbon nanotubes as the adsorbents for the solid‐phase extraction of Chlorpyrifos and Phosalone in water samples using HPLC
Authors: Hadjmohammadi Mohammad Reza , Peyrovi Moazameh , Biparva Pourya 
Published: February 2010

AbstractA comparison between C18 silica and multi‐walled carbon nanotubes (MWCNTs) in the extraction of Chlorpyrifos and Phosalone in environmental water samples was carried out using HPLC. Parameters affecting the extraction were type and volume of elution solvent, pH and flow rate of sample through the adsorbent. The optimum conditions obtained by C18 cartridge for adsorption of these pesticides were 4 mL dichloromethane as elution solvent, sample pH of 5, flow rate of 1 mL/min, and those for MWCNT cartridge were 3 mL dichloromethane, pH of 5 and flow rate of 10 mL/min, respectively. Optimized mobile phase for separation and determination of these compounds by HPLC was methanol/water (80:20 v/v) with pH=5 (adjusted with phosphate buffer). Under optimal chromatographic and SPE conditions, LOD, linear range and precision (RSD n=8) were 3.03×10−3, 0.01–5.00 μg/mL and 2.7% for Chlorpyrifos and 4.03×10−4, 0.01–5.00 μg/mL and 2.3% for Phosalone, in C18 cartridge, respectively. These values for MWCNT were 4.02×10−6, 0.001–0.500 μg/mL and 1.8% for Chlorpyrifos and 1.02×10−6, 0.001–0.500 μg/mL and 1.5% for Phosalone, respectively.
Cotinine as a biomarker of tobacco exposure: Development of a HPLC method and comparison of matrices
Authors: Petersen Guilherme Oliveira , Leite Carlos Eduardo , Chatkin José Miguel , Thiesen Flavia Valladão 
Published: February 2010

AbstractTobacco dependence reaches one‐third of the world population, and is the second leading cause of death around the world. Cotinine, a major metabolite of nicotine, is the most appropriate parameter to evaluate tobacco exposure and smoking status due to its higher stability and half‐life when compared to nicotine. The procedure involves liquid–liquid extraction, separation on a RP column (Zorbax® XDB C8), isocratic pump (0.5 mL/min of water–methanol–sodium acetate (0.1 M)–ACN (50:15:25:10, v/v/v/v), 1.0 mL of citric acid (0.034 M) and 5.0 mL of triethylamine for each liter) and HPLC‐UV detection (261 nm). The analytical procedure proved to be sensitive, selective, precise, accurate and linear (r>0.99) in the range of 5–500.0 ng/mL for cotinine. 2‐Phenylimidazole was used as the internal standard. The LOD was 0.18 ng/mL and the LOQ was 5.0 ng/mL. All samples from smoking volunteers were collected simultaneously to establish a comparison between serum, plasma, and urine. The urinary cotinine levels were normalized by the creatinine and urine density. A significant correlation was found (p<0.01) between all matrices. Results indicate that the urine normalization by creatinine or density is unnecessary. This method is considered reliable for determining cotinine in serum and plasma of smokers and in environmental tobacco smoke exposure.
Development and validation of a method based on a QuEChERS procedure and heart‐cutting GC‐MS for determination of five mycotoxins in cereal products
Authors: Cunha Sara C. , Fernandes José O. 
Published: February 2010

AbstractA new analytical method for the rapid and simultaneous determination of five mycotoxins (zearelenone, deoxynivalenol, Fusarenon X, 15‐acetyldeoxynivalenol and nivalenol) in breakfast cereals and flours by heart‐cutting GC‐MS has been developed and validated. Extraction was performed with MeCN, applying a modified QuEChERS (QUick, Easy, CHeap, Effective, Rugged and Safe) procedure, and the extracts were analyzed after a silylation of the analytes under study. Careful optimization of the parameters of Deans Switch device and GC‐MS was achieved in order to attain a fast separation in SIM mode, allowing a total run time of only 8 min. Acceptable recoveries for all mycotoxins at two different spiking levels (20 and 100 μg/kg) were achieved with good repeatability (from 9 to 21%). LOD ranged from 2 to 15 μg/kg and LOQ ranged from 5 to 50 μg/kg, which were lower than the maximum limit legal established by the European Union (EU). The method developed was applied to commercial breakfast cereals and flours; among the mycotoxins studied, deoxynivalenol and zearalenone were the most predominant.
Synthesis of Cyclodextrin and Sugar‐Based Oligomers for the Efavirenz Drug Delivery
Authors: Shown Indrajit , Banerjee Sudip , Ramchandran A.V. , Geckeler Kurt E. , Murthy C. N. 
Published: February 2010

AbstractSummary: In the present work water‐soluble lactose based oligomers of β‐cyclodextrin were synthesized by a simple and efficient condensation polymerization process. Proposed water‐soluble β‐cyclodextrin oligomers were prepared by controlled reaction between β‐cyclodextrin and a triazine linker and purification by an ultrafiltration process. Similarly, lactose based β‐cyclodextrin oligomers were synthesized for enhanced water solubility. The physical and chemical properties of the synthesized polymers were characterized by FT‐IR and 1H NMR spectroscopy, XRD analysis, thermogravimetric analysis (TGA) and aqueous solubility determination.. Molecular weights of these β‐cyclodextrin based oligomers were measured by ESI technique. These β‐cyclodextrin based water‐soluble oligomers polymers were used as supramolecular carriers for efavirenz (an anti HIV drug), improving the inclusion property and aqueous solubility properties of this drug. These synthesized oligomers were found to improve stability and aqueous solubility of efavirenz on their (1:1) inclusion complex through phase solubility and dissolution studies. Reduced cytotoxicity than the parent β‐CD was observed in hemolysis test.
Impact of Low‐Dosage Inhibitors on Clathrate Hydrate Stability
Authors: Kuznetsova Tatiana , Sapronova Alla , Kvamme Bjørn , Johannsen Klaus , Haug Jarle 
Published: February 2010

AbstractSummary: Development of more capable low‐dosage hydrate inhibitors (LDHI) is of crucial importance to oil and gas industry. Those efforts have been severely hindered so far by lack of clear understanding of molecular‐level mechanisms, both thermodynamic and kinetic, which make certain chemical compounds into efficient inhibitors. An accurate representation of intermolecular potentials between polymeric low dosage inhibitors and hydrate‐water‐gas surfaces is essential for modelling systems containing these components.A two‐stage computational study was undertaken of two proven LDHIs, polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCap), in aqueous solutions under various conditions. We have first carried out ab initio density functional theory (DFT) calculations for PVP and PVCap polymers with molecular weight spanning from monomers to polymeric chains. Molecular dynamics were then employed to investigate thermodynamic and kinetic processes that affect hydrate nucleation and growth. Comparison with experiments has also shown that calculated potential is able to mimic the characteristic behaviour of methane hydrate and PVP complexes.
Application of Meteosat second generation data towards improving the nowcasting of convective initiation
Authors: Siewert Christopher W. , Koenig Marianne , Mecikalski John R. 
Published: February 2010

AbstractThe prediction of convective initiation (CI) from a satellite perspective provides forecasters with a constant relatively high temporal and convective scale spatial resolution tool to help protect life and property. By monitoring infrared (IR) channel brightness temperatures, their trends and multi‐spectral channel differences, the prediction of CI can be accomplished on the 0–1 h timescale. These methods, currently employed on the Geostationary Operational Environmental Satellite (GOES) system, have only recently been explored on the Meteosat Second Generation (MSG) satellite system. The additional channels and derived instability indices available on the MSG satellites may provide additional information useful to the prediction of CI. In this paper a concept is developed and discussed towards the advantages and possible applications of the inclusion of MSG specific IR spectral channels and instability information through the analysis of several convective case events over Central Europe and South Africa. Copyright © 2010 Royal Meteorological Society
Passive planar transmit‐array microstrip lens for microwave purpose
Authors: Padilla P. , Muñoz‐Acevedo A. , Sierra‐Castañer M. 
Published: February 2010

AbstractA complete transmit‐array lens device at 12 GHz, for microwave purpose, is offered in this manuscript.In this document, an overview of the functioning of this kind of devices is given and the proposed transmit‐array lens is thoroughly studied, with architecture discussion and selection, as well as the design, manufacturing, and validation of all the constituting elements of the lens (radiating elements, transmission circuits, and transitions). Eventually, a complete prototype of transmit‐array lens is assembled and radiation pattern measurements in anechoic chamber, as well as gain and directivity values, are offered. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:940–947, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25078
A retrospective study by oligonucleotide array‐CGH analysis in 50 fetuses with multiple malformations
Authors: Valduga M. , Philippe C. , Bach Segura P. , Thiebaugeorges O. , Miton A. , Beri M. , Bonnet C. , Nemos C. , Foliguet B. , Jonveaux P. 
Published: February 2010

AbstractObjectiveTo retrospectively define the frequency and the nature of submicroscopic chromosomal imbalances among fetuses with multiple congenital anomalies (MCA).MethodsWe used oligonucleotide arrays to perform comparative genomic hybridization after termination of pregnancy in 50 polymalformated fetuses with a normal karyotype. These fetuses presented with at least three significant malformations (42 cases) or a severe brain anomaly (eight cases).ResultsWe identified a deleterious copy number variation (CNV) in five fetuses (10%). De novo genomic imbalances identified in this study consisted of a 6qter deletion in a fetus with brain and renal malformations, a mosaicism for a 8p tetrasomy in a fetus with agenesis of corpus callosum, growth retardation, mild facial dysmorphic features, and vertebral anomalies, a 17p13.3 deletion in a fetus with a complex brain malformation, and a partial 11p trisomy in a fetus with severe growth retardation and oligoamnios. In one case, we identified a partial 17q trisomy resulting from malsegregation of a cryptic‐balanced translocation.ConclusionsThis study shows that array comparative genomic hybridization (aCGH) is particularly effective for identifying the molecular basis of the disease phenotype in fetuses with multiple anomalies. Our study should help to define clinical relevant regions that would need to be included in targeted arrays designed for prenatal testing. Copyright © 2010 John Wiley & Sons, Ltd.
‘No sign language if you want to get him talking’: power, transgression/resistance, and discourses of d/Deafness in the Republic of Ireland
Authors: Mathews Elizabeth S. 
Published: February 2010

AbstractThis paper will discuss how, in spite of calls from the Deaf Community for a socio‐cultural model of Deafness to be implemented, a hegemonic medical discourse of deafness is still evident in the health and education systems serving d/Deaf children in the Republic of Ireland. This hegemony is persisting through the social authority of medicine, the exclusion of Deaf professionals from the medical and educational arenas, and the vulnerability of hearing parents as they encounter professional medical services. By examining the evolution of the medical and social models of d/Deafness, focusing in particular on the non‐use and use of Sign Language as signifiers of the medical and social models respectively, this paper situates the current state of deaf education in Ireland in the context of complex historical processes and relative concepts of power. While there are examples of transgression/resistance to the system, it will be argued that the temporal and spatial limitations on these acts obstruct them from challenging the system overall. This has been further compounded by the changing spatial nature of this resistance, as more and more d/Deaf children make their way through mainstream education. Copyright © 2010 John Wiley & Sons, Ltd.
Electronic excitations and optical spectra of Pt2 and Pt4 on Cu(001) modeled by a cluster
Authors: Pal George , Lefkidis Georgios , Hübner Wolfgang 
Published: February 2010

AbstractThe photoabsorption spectra of Pt2 and Pt4 clusters on the Cu(001) surface are computed using two different theoretical methods: the symmetry‐adapted cluster expansion configuration interaction from quantum chemistry and a recently developed linear response approach to treat electron–hole correlations in the presence of an external electromagnetic field. Comparing the energetically low‐lying optical excitations, we find very good agreement between the two methods. For different orientations of the adsorbed clusters with respect to the surface, we find that the most intense optical peaks occur when the polarization of the applied laser pulse is parallel to the surface.
Bodily variability of zinc natural isotope abundances in sheep
Authors: Balter Vincent , Zazzo Antoine , Moloney Aidan P. , Moynier Fred , Schmidt Olaf , Monahan Frank J. , Albarède Francis 
Published: February 2010

AbstractEvidence is growing that the range of zinc stable isotope compositions, represented by the deviation of 66Zn in permil units relative to a standard and expressed as δ66Zn, is larger in organic matter than in inorganic material. This study reports the variations of δ66Zn in various organs of sheep raised on a controlled diet. Zinc was purified by anion‐exchange chromatography. The Zn concentrations and Zn stable isotope compositions were determined by quadrupole inductively coupled plasma mass spectrometry and multi‐collector inductively coupled plasma mass spectrometry, respectively. The data show that δ66Zn variability exceeds 1‰, with bone, muscle, serum and urine enriched in the heavy isotopes, and feces, red blood cells, kidney and liver enriched in light isotopes, all relative to the diet value. The 66Zn enrichment of the circulating serum reservoir is likely to take place in the digestive tract, probably through the preferential binding of lighter isotopes with phytic acid, which is known to control the uptake of metallic elements. Mass balance calculations suggest that the 66Zn depletion between diet and feces, which is not balanced by any other outward flux, leads to a secular isotopic drift in serum. A simple time‐dependent two‐box model, involving the gastro‐intestinal tract on the one hand and the muscle and bone on the other, predicts that the maximum 66Zn enrichment, which equals the difference in δ66Zn between diet and bulk (∼0.25‰), is reached after about ten years. Therefore, a better understanding of the variations of natural abundance of Zn isotopes in animals and humans will probably bring new perspectives for the assessment of their Zn status. Copyright © 2010 John Wiley & Sons, Ltd.
Liquid chromatographic/electrospray ionization mass spectrometric identification of the oxidation end‐products of trans‐resveratrol in aqueous solutions
Authors: Camont Laurent , Collin Fabrice , Marchetti Catherine , Jore Daniel , Gardes‐Albert Monique , Bonnefont‐Rousselot Dominique 
Published: February 2010

Abstracttrans‐Resveratrol (3,5,4′‐trihydroxystilbene) is a natural polyphenolic compound that exhibits antioxidant properties. Our study aimed at studying the HO.‐induced oxidation of resveratrol (100 µmol.L−1) in aerated aqueous solutions. Gamma radiolysis of water was used to generate HO./O free radicals (I = 10 Gy.min−1, dose = 400 Gy). Oxidation products were identified by direct infusion mass spectrometry and high‐performance liquid chromatography/mass spectrometry. For each product, structural elucidation was based on simple mass spectra, fragmentation spectra and deuterium/hydrogen exchange spectra; the comparison with mass spectra of synthetic products provided valuable information allowing the complete identification of the oxidation products. Four products resulting from the direct attack of HO. radicals towards resveratrol were identified respectively as piceatannol (trans‐3,5,3′,4′‐tetrahydroxystilbene), 3,5‐dihydroxybenzoic acid, 3,5‐dihydroxybenzaldehyde and 4‐hydroxybenzaldehyde. Copyright © 2010 John Wiley & Sons, Ltd.
Systematic screening and characterization of novel bufadienolides from toad skin using ultra‐performance liquid chromatography/electrospray ionization quadrupole time‐of‐flight mass spectrometry
Authors: Liu Yanfang , Xiao Yuansheng , Xue Xingya , Zhang Xiuli , Liang Xinmiao 
Published: February 2010

AbstractDuring the discovery process of novel compounds, it is of significant importance to differentiate novel from known compounds in crude extracts before starting the time‐consuming process of purification. Bufadienolides are the main active components of the skin of the toad Bufo bufo gargarizans Cantor (toad skin), an important traditional Chinese medicine. The fragmentation behavior and mass spectra profiles of bufadienolides standards were investigated using ultra‐performance liquid chromatography/electrospray ionization quadrupole time‐of‐flight mass spectrometry (UPLC/ESI‐Q‐TOFMS). Several fragmentation rules were summarized and applied to characterize novel and known bufadienolides in toad skin. Characteristic substituent groups could be identified by both diagnostic ions and their relative abundance. Bufadienolide stereoisomers could be differentiated from positional isomers by comparing fragment abundance profiles. This was used to characterize new stereoisomers for known bufadienolides. A total of 39 bufadienolides were screened out using a systematic method developed in our laboratory. In addition to 19 known bufadienolides, 20 putative novel compounds, including 8 stereoisomers, were characterized. UPLC/Q‐TOFMS was demonstrated to be a powerful tool for the characterization of low‐abundance bufadienolides in complex samples. This study provides guidelines for the targeted isolation of novel bufadienolides from natural products. Copyright © 2010 John Wiley & Sons, Ltd.
Abundance and function of large woody debris in small, headwater streams in the Rocky Mountain foothills of Alberta, Canada
Authors: Jones T. A. , Daniels L. D. , Powell S. R. 
Published: February 2010

AbstractLarge woody debris (LWD) significantly influences the structure and function of small headwater streams. However, what it contributes to geomorphic function depends on where it is located relative to the stream channel. We quantified LWD abundance and tested for associations among decay, position, orientation and function classes in 21 streams near Hinton, Alberta, Canada. LWD was more frequent (64.0 ± 3.3 LWD 100 m−1) in streams in the Alberta foothills than it was in small streams in mountain, coastal, broadleaf deciduous and boreal forests, likely due to the narrow channel widths and low capacity of our study streams to transport logs downstream. LWD volumes were greater in coastal streams than in the Alberta foothills, likely due to differing tree sizes and decay rates. LWD morphology changed significantly as logs decayed and transitioned to different position and orientation classes. LWD in decay classes I and II were longest, most commonly in the bridge and partial bridge position classes, oriented perpendicular to stream flow, suspended above the channel and contributing least to stream geomorphic functions. LWD length and volume (but not diameter) decreased as decay advanced, making logs less stable. LWD in decay classes III and IV were strongly associated with partially bridged, loose, and buried position classes. They were more commonly diagonal or parallel to stream flow and contributed to bank stability, sediment retention, debris jams and riffle and pool formations. These results have been integrated into a conceptual model of LWD dynamics that provides a framework for future research on the mechanisms and rates of LWD recruitment, decay, transport and function. Copyright © 2010 John Wiley & Sons, Ltd.
Effects of fragmented breeding habitat and resource distribution on behavior and survival of the bank vole (Myodes glareolus)
Authors: Haapakoski Marko , Ylönen Hannu 
Published: February 2010

AbstractHabitat fragmentation causes negative population trends or even local extinction in many species. Understanding the role of fragmentation on behavior and space use of animals is an essential part of revealing the mechanism behind observed population declines. We studied experimentally the effects of small‐scale habitat fragmentation on the distribution and movement of bank voles (Myodes glareolus) in seminatural enclosures. We predicted that besides habitat structure, availability of two resources, food for both sexes, and receptive females for males, determine individual distribution. We manipulated female density (either 0, 4, or 12 per enclosure) and followed movements of radio‐collared males. We also studied the effect of unequal food distribution between the fragments on vole distribution. The habitat of 0.25‐ha enclosures was manipulated by forming either one large, two medium‐sized, or four small habitat patches surrounded by an inhospitable matrix. Female density and distribution clearly affected male spacing behavior. Males had larger home ranges in the medium female density enclosures. Furthermore, the use of the inhospitable and risky matrix area increased with habitat fragmentation. Food supplementation improved individual condition measured as body mass but did not affect breeding success. Our experiments demonstrated that both small‐scale habitat fragmentation and resource distribution affect the behavior and condition of individuals. Increased fragmentation led to increased risk taking in both mating and foraging behavior. This should have direct survival and fitness consequences, and therefore our results may be extrapolated to population‐level consequences of habitat fragmentation.
Reproductive biology of the highly commercial polychaetes in the Suez Canal
Authors: Osman Inas H. , Gabr Howaida R. , Saito Hidetoshi , El-Etreby Salah Gh. 
Published: February 2010

The reproductive biology of the commercial seabait polychaete speciesPerinereis nuntia brevicirris, Lumbrineris funchalensisandHalla parthenopeiawas investigated from samples obtained from the Suez Canal, Egypt, to determine sex-ratio, reproductive maturity stages, spawning season, and fecundity. Samples were collected monthly from January 2002 to February 2003. The results of sex-ratio indicated that males of the three studied worms outnumbered females through the whole study period. Based upon histological features of the coelomic contents, four maturity stages were described in females ofP. nuntia brevicirris, three stages were described for females ofL. funchalensisand three stages for females ofH. parthenopeia. The spawning season ofP. nuntia brevicirriswas found to take place during spring andL. funchalensisdoes not have a defined breeding season, whileH. parthenopeiahas two reproductive periods, one in May and the second in November and lasted to January. Fecundity was estimated by counting the number of oocytes per each female—it showed thatP. nuntia brevicirrisis more fecund (mean = 208.358 ±2080 oocyte/female) thanL. fanchalensisandH. parthenopeia(mean = 2660 ±654 and 142,068 ±2005 oocyte/female respectively). This study is the first to document aspects of the reproductive biology of the highly commercial polychaetes in the Suez Canal and adds to our knowledge for understanding their reproductive patterns and strategies.