bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role ofCYP2A6in the Emergence of Nicotine Dependence in Adolescents
Authors: Audrain-McGovern Janet , Koudsi Nael Al , Rodriguez Daniel , Wileyto E. Paul , Shields Peter G. , Tyndale Rachel F. 
Published: November 2006

OBJECTIVES. The objectives of our study were to evaluate whether genetic variation in nicotine metabolic inactivation accounted for the emergence of nicotine dependence from mid- to late adolescence and whether initial smoking experiences mediated this effect.METHODS. Participants were 222 adolescents of European ancestry who participated in a longitudinal cohort study of the biobehavioral determinants of adolescent smoking. Survey data were collected annually from grade 9 to the end of grade 12. Self-report measures included nicotine dependence, smoking, age first smoked, initial smoking experiences, peer and household member smoking, and alcohol and marijuana use. DNA collected via buccal swabs was assessed for CYP2A6 alleles that are common in white people and are demonstrated to decrease enzymatic function (CYP2A6*2, *4, *9, *12).RESULTS. Latent growth-curve modeling indicated that normal metabolizers (individuals with no detected CYP2A6 variants) progressed in nicotine dependence at a faster rate and that these increases in nicotine dependence leveled off more slowly compared with slower metabolizers (individuals with CYP2A6 variants). Initial smoking experiences did not account for how CYP2A6 genetic variation impacts nicotine dependence.CONCLUSIONS. These findings may help to promote a better understanding of the biology of smoking behavior and the emergence of nicotine dependence in adolescents and inform future work aimed at understanding the complex interplay between genetic, social, and psychological factors in adolescent smoking behavior.
Evaluation and interlaboratory validation of a GC-MS method for analysis of pesticide residues in teas
Authors: Peng C. , Kuang H. , Li X. , Xu C. 
Published: November 2006

AbstractA method was described for simultaneous determination of nine organic heterocyclic pesticide residues by gas chromatography-mass spectrometry-selected ion monitoring. Atrazine, vinclozolin, procymidone, triflumizole, imazalil, buprofezin, propiconazole, fenarimol, and pyridaben were clearly separated from each other, extracted with acetone—hexane mixture, purified with graphitized carbon black cartridge and neutral Al2O3 cartridge, eluted with acetone—hexane mixture, simultaneously determined by GC-MS, and then quantified with an external standard method. Recoveries of pesticides ranged from 73 % to 116 % at the spiked level of 0.01–30 mg kg−1, while the relative standard deviation was between 3 % and 27 %. In addition, the limits of determination (0.01 mg kg−1 to 5.0 mg kg−1) and linearity (0.02–40 μg mL−1) revealed that simultaneous determination of multi-residues in Chinese teas (like Oolong tea, green tea, red tea, etc.) was possible. Furthermore, an interlaboratory study among 5 labs was conducted to further validate the method, and the results were satisfactory.
Influence of composition on corroding process of Na2O-K2O-CaO-ZrO2-SiO2 glasses
Authors: Staňová I. , Plško A. , Pagáčová J. , Šibíková K. 
Published: November 2006

AbstractThe corroding process of six glasses of the Na2O-K2O-CaO-ZrO2-SiO2 system with ZrO2content 0–2.13 mass % by water was observed during static tests at 121°C and pressure of 0.25 MPa in steam sterilizer. Significant increase of Na+ and K+ content in leachates was observed after the addition of ZrO2 into glass. Further increase of the content of ZrO2 in glasses slowed down the rate of Na+ and K+ leaching. The leaching process of SiO2 as well as Na+, K+, and Ca2+ ions was evaluated on the basis of comparison with model leaching processes. Variation of the concentrations of Na+, K+, Ca2+, and SiO2 in leachates with time was described by empirical equation. Observed changes in the initial leaching rates of Na+, K+, Ca2+, and SiO2 can be ascribed to the content of ZrO2 in glasses. The presence of ZrO2 in glasses reduced the overall rate of glass dissolution.
Comparison of chemical properties of food products processed by conventional and ohmic heating
Authors: Pereira R. , Pereira M. , Teixeira J. , Vicente A. 
Published: November 2006

AbstractThe effect of ohmic and conventional heat processing of different food products on their chemical and physical parameters was studied. Depending on the food being analysed, parameters such as pH, total solids, ash, titratable acidity, ascorbic acid, total sugars, total fatty acids, total phenolic compounds, and anthocyanins content were determined before and after ohmic and conventional pasteurization techniques and the results were compared using one-way analysis of variance. In goat milk samples treated by ohmic technology the pH value (6.58) and total fatty acids content in milk fat (86.5 mass %) were comparable to those found in milk treated by conventional process, however, ohmically treated samples presented a lower content of lactic acid, 0.13 %. In cloudberry jam samples treated by ohmic technology the results of some of the main parameters tested, such as total sugar content 46.1 mass %, ascorbic acid content 2.83 mass %, and titratable acidity 6.01 mass % (as citric acid) did not show significant differences when compared with samples treated by conventional technology.
Origin of the π‐Facial Stereoselectivity in the Addition of Nucleophilic Reagents to Chiral Aliphatic Ketones as Evidenced by High‐Level Ab Initio Molecular‐Orbital Calculations
Authors: Takahashi Osamu , Yamasaki Katsuyoshi , Kohno Yuji , Ueda Kazuyoshi , Suezawa Hiroko , Nishio Motohiro 
Published: November 2006

AbstractAb initio molecular‐orbital (MO) calculations were carried out, at the MP2/6‐311++G(d,p)//MP2/6‐31G(d) level, to investigate the conformational Gibbs energy of alkyl 1‐cyclohexylethyl ketones, cyclo‐C6H11CHCH3COR (R=Me, Et, iPr, and tBu). In each case, one of the equatorial conformations was shown to be the most stable. Conformers with the axial CHCH3COR group were also shown to be present in an appreciable concentration. Short CH⋅⋅⋅CO and CH⋅⋅⋅OC distances were found in each stable conformation. The result was interpreted on the grounds of CH⋅⋅⋅π(CO) and CH⋅⋅⋅O hydrogen bonds, which stabilize the geometry of the molecule. The ratio of the diastereomeric secondary alcohols produced in the nucleophilic addition to cyclo‐C6H11CHCH3COR was estimated on the basis of the conformer distribution. The calculated result was consistent with the experimental data previously reported: the gradual increase in the product ratio (major/minor) along the series was followed by a drop at R=tBu. The energy of the diastereomeric transition states in the addition of LiH to cyclo‐C6H11CHCH3COR was also calculated for R=Me and tBu. The product ratio did not differ significantly in going from R=Me to tBu in the case of the aliphatic ketones. This is compatible with the above result calculated on the basis of the conformer distribution. Thus, the mechanism of the π‐facial selection can be explained in terms of the simple premise that the geometry of the transition state resembles the ground‐state conformation of the substrates and that the nucleophilic reagent approaches from the less‐hindered side of the carbonyl π face.
Quantification of intracellular homocysteine by stable isotope dilution liquid chromatography/tandem mass spectrometry
Authors: Huang Yuehua , Lu Zhi‐Yong , Brown Karen S. , Whitehead Alexander S. , Blair Ian A. 
Published: November 2006

AbstractA precise and accurate stable isotope dilution liquid chromatography/tandem mass spectrometry method for the analysis of intracellular homocysteine has been developed. An internal standard, [2H8]‐homocystine, was added to cell pellets from EA.hy 926 cells grown in culture under low and high folate concentrations. d,l‐dithiothreitol was used to reduce cellular homocystine to homocysteine. Cellular proteins were precipitated by the addition of formic acid in acetonitrile. After centrifugation, a portion of the supernatant was analyzed by liquid chromatography/tandem mass spectrometry. Using a Supelcosil cyano column with an Applied Biosystems API 4000 triple quadrupole mass spectrometer, the SRM transitions for homocysteine (m/z 136 to m/z 90) and [2H4]‐homocysteine (m/z 140 to m/z 94) were monitored. The method was validated by conducting five replicate analyses on three different days at four different concentrations (concentrations at the lower limit of quantitation and expected lower quartile, mid‐range and upper quartile). The limit of detection was 2 ng/106 EA.hy 926 cells. Using this method, the intracellular homocysteine concentration in EA.hy 926 cells ranged from 10 to 36 ng/106 cells. Copyright © 2006 John Wiley & Sons, Ltd.
Thermo‐poro‐mechanical properties of clayey gouge and application to rapid fault shearing
Authors: Sulem J. , Lazar P. , Vardoulakis I. 
Published: November 2006

AbstractIn this paper, the mechanism of fault pressurization in rapid slip events is analysed on the basis of a complete characterization of the thermo‐poro‐mechanical behaviour of a clayey gouge extracted at 760 m depth in Aigion fault in the active seismic zone of the Gulf of Corinth, Greece. It is shown that the thermally collapsible character of this clayey gouge can be responsible for a dramatic reduction of effective stress and a full fluidization of the material. The thickness of the ‘ultra‐localized’ zone of highly strained material is a key parameter that controls the competing phenomena of pore pressure increase leading to fluidization of the fault gouge and temperature increase leading to pore‐fluid vapourization. Copyright © 2006 John Wiley & Sons, Ltd.
Identification of the nitration site of insulin by peroxynitrite
Authors: Chi Quan , Huang Kaixun 
Published: November 2006

AbstractOur previous investigation indicated that insulin can be nitrated by peroxynitrite in vitro. In this study, the preferential nitration site of the four tyrosine residues in insulin molecule was confirmed. Mononitrated and dinitrated insulins were purified by RP‐HPLC. Following reduction of insulin disulfide bridges, Native‐PAGE indicated that A‐chain was preferentially nitrated. Combination of enzymatic digestion of mononitrated insulin with endoproteinase Glu‐C, mass spectrometry confirmed that Tyr‐A14 was the preferential nitration site when insulin was treated with peroxynitrite. Tyr‐A19, maybe, was the next preferential nitration site. According to the crystal structure, Tyr‐B26 between the two tyrosine residues in insulin B‐chain was likely easier to be nitrated by peroxynitrite. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Vibrational properties of GaP and GaP1–xNx under hydrostatic pressures up to 30 GPa
Authors: Jackson M. P. , Halsall M. P. , Güngerich M. , Klar P. J. , Heimbrodt W. , Geisz J. F. 
Published: November 2006

AbstractWe report on Raman scattering of the vibrational modes of GaP and the dilute nitride ternary GaP0.979N0.021 under hydrostatic pressures of up to 30 GPa. We measured the pressure induced shift of the TO and LO modes of GaP up to the phase transition (I–II) and determined mode Grüneisen parameters of 1.12 and 0.98. The phase transition was observed near to 24.5 GPa. We have also studied the dependence of the vibrational spectrum of the GaP0.979N0.021 up to 20 GPa. The zincblende optical phonons of the ternary alloy show great similarities to those of binary GaP, with no significant changes to the Grüneisen parameters or the phase transition. The pressure‐induced shift of local nitrogen mode frequency in GaP0.979N0.021 was studied up to 10 GPa and found to be considerably larger than that of the phonon modes in GaN, indicating that the local mode does not show a GaN‐like behaviour under pressure. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Au nanolayers deposited on polyethyleneterephtalate and polytetrafluorethylene degraded by plasma discharge
Authors: Švorčík V. , Siegel J. , Slepička P. , Kotál V. , Švorčíková J. , Špirková M. 
Published: November 2006

AbstractPolyethyleneterephtalate (PET) and polytetrafluorethylene (PTFE) foils were modified by plasma discharge. The effect of plasma modification on polymer surface wettability and on properties of gold coatings were studied as a function of time from plasma exposure (aging time) and polymer substrate temperature. Thickness, sheet resistance, and surface topology of gold layers were studied. Aging of the plasma‐exposed samples is accompanied by increase in contact angle, which is explained by rearrangement of the polymer segments in the polymer surface monolayer, and a decrease in the concentration of polar groups. The aging also leads to a decline in surface roughness Ra measured by atomic force microscopy (AFM). Under deposition conditions, comparable thicknesses of deposited Au layers were prepared on pristine PET and plasma‐treated PET and PTFE samples. The thinnest Au layers were evaporated onto pristine PTFE. The sheet resistance decreases with increasing thickness of Au layer. Plasma treatment leads to an increase of PTFE surface roughness, which becomes even more pronounced after Au deposition. A higher roughness shows that the PET samples are deposited with the Au layer at temperatures above the glassy transition temperature Tg. Copyright © 2006 John Wiley & Sons, Ltd.
Biology teachers' attitudes toward and use of Indiana's evolution standards
Authors: Donnelly Lisa A. , Boone William J. 
Published: November 2006

AbstractThis study examines the relationship between biology teachers' evolution teaching practices and their regard and use of Indiana state evolution standards. A survey developed by the authors contained five subscales: use of standards; attitude toward standards; attitude toward evolution standards; evolution teaching practices; and demographic information. This survey was administered to 229 Indiana biology teachers. Data were analyzed using the Rasch model to convert Likert rating scale data into ratio data used for parametric analyses. Correlation analysis revealed significant relationships between use of standards and attitude toward standards, attitude toward standards and evolution teaching practices, and attitude toward evolution standards and days teaching evolution. These findings suggest practical relationships between standards use, teachers' regard of standards, and evolution teaching practices. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 236–257, 2007
Sonographic detection of fetal cerebellar cavernous hemangioma with in‐utero hemorrhage leading to cerebellar hemihypoplasia
Authors: Lerner A. , Gilboa Y. , Gerad L. , Malinger G. , Kidron D. , Achiron R. 
Published: November 2006

AbstractWe report the prenatal diagnosis of cerebellar cavernous angioma. Ultrasound examination at 21 weeks' gestation showed a hyperechogenic lesion measuring 12 mm in diameter, occupying most of the right cerebellar hemisphere. At 24 weeks' gestation, significant hypoplasia of the right hemisphere was diagnosed, and the pregnancy was terminated. Pathological evaluation of the lesion revealed extensive hemorrhaging and a rich network of dilated vessels and small capillaries. The right cerebellar lobe was hypoplastic and covered with blood clots. Cerebral cavernous malformation should be considered in the differential diagnosis of hyperechogenic lesions in the fetal cerebellum. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Multiply antibiotic-resistantVibrio choleraeO1 biotype El Tor strains emerge during cholera outbreaks in Zambia
Authors: MWANSA J. C. L. , MWABA J. , LUKWESA C. , BHUIYAN N. A. , ANSARUZZAMAN M. , RAMAMURTHY T. , ALAM M. , BALAKRISH NAIR G. 
Published: November 2006

SUMMARYAntibiotic resistance data, made available from laboratory records during eight cholera outbreaks between 1990 and 2004 showedVibrio choleraeserogroup O1 to have a low level of resistance (2–3%) to tetracycline during 1990–1991. Resistance increased for tetracycline (95%), chloramphenicol (78%), doxycycline (70%) and trimethoprim–sulphamethoxazole (97%) in subsequent outbreaks. A significant drop in resistance to tetracycline and chloramphenicol followed the adoption of a national policy to replace tetracycline with erythromycin for treating cholera. Sixty-nine strains from cholera outbreaks in Zambia between 1996 and 2004, were examined for antibiotic resistance and basic molecular traits. A 140 MDa conjugative, multidrug-resistant plasmid was found to encode tetracycline resistance in strains from 1996/1997 whereas strains from 2003/2004 were resistant to furazolidone, but susceptible to tetracycline, and lacked this plasmid. PCR revealed 25 of 27 strains from 1996/1997 harboured theintl1class 1 integron but lacked SXT, a conjugative transposon element. Similar screening of 42 strains from 2003/2004 revealed all carried SXT but not theintl1class 1 integron. All 69 strains, except two, one lackingctxAand the otherrstRand thus presumably truncated in the CTX prophage region, were positive for important epidemic markers namelyrfbO1,ctxA,rstR2, andtcpAof El Tor biotype. Effective cholera management is dependent on updated reports on culture and sensitivity to inform the choice of antibiotic. Since the emergence of antibiotic resistance may significantly influence strategies for controlling cholera, continuous monitoring of epidemic strains is crucial.
Reforming the WTO Legal Order for Agricultural Trade: Issues for European Rural Policy in the Doha Round
Authors: Cardwell Michael , Rodgers Christopher 
Published: November 2006

AbstractEuropean farm policy has undergone radical change in recent years, culminating in the Agenda 2000 reforms to the Common Agricultural Policy agreed in 1999 and then their Mid-Term Review in 2003. In particular, subsidy payments have been substantially ‘decoupled’ from production and switched decisively towards providing income support for farmers under a new ‘single farm payment’ scheme. These reforms have been predicated upon the need to win acceptance for Community farm subsidies in the Doha Round of WTO negotiations. This article examines the new law of the Common Agricultural Policy against the background of the domestic support reduction commitments contained in the 1994 Uruguay Round Agreement on Agriculture. It questions the extent to which the single farm payment scheme fulfils the requirements for ‘green box’ exemption from such commitments. Options for the re-negotiation of the Agreement on Agriculture are discussed, including measures to improve the justiciability of its terms and to exclude discriminatory and trade-distorting domestic support. The article also considers the implications of the recent WTO Appellate Body Decisions inUnited States—Subsidies on Upland Cotton and European Communities-Export Subsidies on Sugar. It concludes that the Community will have difficulty gaining acceptance for its reforms among WTO Members. Whatever the legitimacy of its subsidy regime within the framework of the current Agreement on Agriculture, the emergence of a strong negotiating position among developing countries, posited on opposition to the volume of farm support maintained by the Community and United States, may present even greater obstacles to the conclusion of a new Agreement on Agriculture in the Doha Round.
Arabidopsis CUP-SHAPED COTYLEDON3Regulates Postembryonic Shoot Meristem and Organ Boundary Formation
Authors: Hibara Ken-ichiro , Karim Md. Rezaul , Takada Shinobu , Taoka Ken-ichiro , Furutani Masahiko , Aida Mitsuhiro , Tasaka Masao 
Published: November 2006

AbstractOverall shoot architecture in higher plants is highly dependent on the activity of embryonic and axillary shoot meristems, which are produced from the basal adaxial boundaries of cotyledons and leaves, respectively. In Arabidopsis thaliana, redundant functions of the CUP-SHAPED COTYLEDON genes CUC1, CUC2, and CUC3 regulate embryonic shoot meristem formation and cotyledon boundary specification. Their functional importance and relationship in postembryonic development, however, is poorly understood. Here, we performed extensive analyses of the embryonic and postembryonic functions of the three CUC genes using multiple combinations of newly isolated mutant alleles. We found significant roles of CUC2 and CUC3, but not CUC1, in axillary meristem formation and boundary specification of various postembryonic shoot organs, such as leaves, stems, and pedicels. In embryogenesis, all three genes make significant contributions, although CUC3 appears to possess, at least partially, a distinct function from that of CUC1 and CUC2. The function of CUC3 and CUC2 overlaps that of LATERAL SUPPRESSOR, which was previously shown to be required for axillary meristem formation. Our results reveal that redundant but partially distinct functions of CUC1, CUC2, and CUC3 are responsible for shoot organ boundary and meristem formation throughout the life cycle in Arabidopsis.
Arabidopsis NRP1andNRP2Encode Histone Chaperones and Are Required for Maintaining Postembryonic Root Growth
Authors: Zhu Yan , Dong Aiwu , Meyer Denise , Pichon Olivier , Renou Jean-Pierre , Cao Kaiming , Shen Wen-Hui 
Published: November 2006

AbstractNUCLEOSOME ASSEMBLY PROTEIN1 (NAP1) is conserved from yeast to human and was proposed to act as a histone chaperone. While budding yeast contains a single NAP1 gene, multicellular organisms, including plants and animals, contain several NAP1 and NAP1-RELATED PROTEIN (NRP) genes. However, the biological role of these genes has been largely unexamined. Here, we show that, in Arabidopsis thaliana, simultaneous knockout of the two NRP genes, NRP1 and NRP2, impaired postembryonic root growth. In the nrp1-1 nrp2-1 double mutant, arrest of cell cycle progression at G2/M and disordered cellular organization occurred in root tips. The mutant seedlings exhibit perturbed expression of ∼100 genes, including some genes involved in root proliferation and patterning. The mutant plants are highly sensitive to genotoxic stress and show increased levels of DNA damage and the release of transcriptional gene silencing. NRP1 and NRP2 are localized in the nucleus and can form homomeric and heteromeric protein complexes. Both proteins specifically bind histones H2A and H2B and associate with chromatin in vivo. We propose that NRP1 and NRP2 act as H2A/H2B chaperones in the maintenance of dynamic chromatin in epigenetic inheritance.
The effects of cosolutes on protein dynamics: The reversal of denaturant‐induced protein fluctuations by trimethylamine N‐oxide
Authors: Doan‐Nguyen Vicky , Loria J. Patrick 
Published: November 2006

AbstractThe protein stabilizing effects of the small molecule osmolyte, trimethylamine N‐oxide, against chemical denaturant was investigated by NMR spin‐relaxation measurements and model‐free analysis. In the presence of 0.7 M guanidine hydrochloride increased picosecond‐nanosecond dynamics are observed in the protein ribonuclease A. These increased fluctuations occur throughout the protein, but the most significant increases in flexibility occur at positions believed to be the first to unfold. Addition of 0.35 M trimethylamine N‐oxide to this destabilized form of ribonuclease results in significant rigidification of the protein backbone as assessed by 1H‐15N order parameters. Statistically, these order parameters are the same as those measured in native ribonuclease indicating that TMAO reduces the amplitude of backbone fluctuations in a destabilized protein. These data suggest that TMAO restricts the bond vector motions on the protein energy landscape to resemble those motions that occur in the native protein and points to a relation between stability and dynamics in this enzyme.