bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Structure, and Theoretical Study of Lower Trifluoromethyl Derivatives of [60]Fullerene
Authors: Dorozhkin Evgenii I. , Goryunkov Alexey A. , Ioffe Ilya N. , Avdoshenko Stanislav M. , Markov Vitaliy Yu. , Tamm Nadezhda B. , Ignat'eva Daria V. , Sidorov Lev N. , Troyanov Sergey I. 
Published: August 2007

AbstractA number of C60(CF3)n compounds with n = 2–10 have been synthesized by the reaction of C60 with silver trifluoroacetate and successfully isolated by means of HPLC. This resulted in the first crystal structure determination of six lower trifluoromethyl derivatives with n = 2 (single isomer), 4 (two isomers), and 6 (three isomers). A kinetic model of sequential trifluoromethylation based on the Bell–Evans–Polanyi principle has been used to explain the experimentally observed isomeric distribution in the mixtures of C60(CF3)n compounds up ton = 6. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A detailed analysis of hotspots and insulation breakdown phenomena in power inductor windings at high frequency regimes: overcurrents and overvoltages
Authors: Faria J. A. Brandão 
Published: August 2007

AbstractThis research paper is the last of a group of three papers dedicated to the analysis and computation of the high‐frequency electromagnetic behaviour of inductor windings where a multiconductor transmission line approach is used. The present work is essentially concerned with application aspects linked up with the important engineering problem of windings insulation damage, which can occur either because of excessive temperature (winding hotspots) or because of excessive electric field strength (dielectric breakdown). For single and multilayer windings we present here a wealth of information in graphical and tabular form concerning the distribution of voltages, currents, electric charges, charge densities, electric field components and power losses along the inductor winding turns, operating at the critical resonance frequencies characteristic of the structure (which is the worst possible scenario). This information is analysed and processed in order to allow for a detection of the winding zones where breakdown phenomena and hotspots could most probably occur. Copyright © 2007 John Wiley & Sons, Ltd.
MGF for gamma‐shadowed ricean fading channel
Authors: Kostić I. M. 
Published: August 2007

AbstractThe moment‐generating function (MGF) of the received signal‐to‐noise ratio (SNR) is a convenient tool in the performance analysis of modulation schemes in fading channels. In this letter, we derive the MGF for gamma‐shadowed Ricean fading channels under the assumption that the average power of the Ricean fading is characterised by a gamma distribution. The MGF is expressed in a series form. An application of the derived MGF for evaluating the average bit error probability (ABEP) for binary differential phase‐shift keying (DPSK) is given. The exact expression for ABEP and the corresponding asymptotic expression (assuming large SNR) are derived and mutually compared. The computational efficiency is elaborated on. Special cases of the exact expression for ABEP agree with corresponding known results. Copyright © 2007 John Wiley & Sons, Ltd.
Mechanisms of cytochrome P450 substrate oxidation: MiniReview
Authors: Guengerich F. Peter 
Published: August 2007

AbstractCytochrome P450 (P450) enzymes catalyze a variety of oxidation and some reduction reactions, collectively involving thousands of substrates. A general chemical mechanism can be used to rationalize most of the oxidations and involves a perfenyl intermediate (FeO3+) and odd‐electron chemistry, i.e. abstraction of a hydrogen atom or electron followed by oxygen rebound and sometimes rearrangement. This general mechanism can explain carbon hydroxylation, heteroatom oxygenation and dealkylation, epoxidation, desaturation, heme destruction, and other reactions. Another approach to understanding catalysis involves analysis of the more general catalytic cycle, including substrate specificity, because complex patterns of cooperativity are observed with several P450s. Some of the complexity is due to slow conformational changes in the proteins that occur on the same timescale as other steps. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:163–168, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20174
Ontogeny of human hepatic cytochromes P450
Authors: Hines Ronald N. 
Published: August 2007

AbstractSignificant changes in drug‐metabolizing enzyme (DME) expression occur during ontogeny. Such changes can have a profound effect on therapeutic efficacy in the fetus and child, as well as the risk for adverse drug reactions. To gain a better understanding of DME ontogeny, enzyme contents for six key cytochromes P450 were measured in 240 human liver samples representing ages from 8 weeks gestation to 18 years. Where possible, both quantitative western blotting and activity assays with probe substrates were performed. Although oversimplified, the DME can be grouped into one of three categories. As typified by CYP3A7, some enzymes are expressed at their highest level during the first trimester and either remain at high concentrations or decrease during gestation and are silenced or expressed at low levels within 1–2 years after birth. These data cause one to query whether these enzymes have an important endogenous function. Representatives of a second group, CYP3A5 and CYP2C19, are expressed at relatively constant levels throughout gestation. Postnatal increases in CYP2C19 are observed within the first year, but not for CYP3A5. CYP2C9, 2E1, and 3A4 are more typical of a third group of enzymes that are not expressed or are expressed at low levels in the fetus with the onset of expression generally in either the second or third trimester. Substantial increases in expression are observed within the first 1–2 years after birth; however, considerable interindividual variability is observed in the immediate postnatal (1–6 months) onset or increase in expression of these enzymes, often resulting in a window of hypervariability. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:169–175, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20179
Mechanisms of cytochrome P450 induction
Authors: Tompkins Leslie M. , Wallace Andrew D. 
Published: August 2007

AbstractCytochrome P450s (CYPs) are important heme‐containing proteins that play important roles in the metabolism of xenobiotics and endogenous compounds. The oxidative metabolisms of drugs, environmental chemicals, hormones, and fatty acids by CYP enzymes are critical pathways aiding in their excretion from the body, but in some cases metabolism may lead to bioactivation and enhanced toxicity. The expression and activity levels of CYPs can be elevated by a process of induction involving the activation of key transcription factors. The mechanisms by which CYP3A4, 2B6, and 1A1 are induced involving the activation of the transcription factors pregnane X receptor (PXR), constitutive androstane receptor (CAR), and aryl hydrocarbon receptor (AhR) will be discussed. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:176–181, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20180
Theoretical study of the reactions CF3CH2OCHF2 + OH/Cl and its product radicals and parent ether(CH3CH2OCH3) with OH
Authors: Yang Lei , Liu Jing‐Yao , Wang Li , He Hong‐Qing , Wang Ying , Li Ze‐Sheng 
Published: August 2007

AbstractA dual‐level direct dynamic method is employed to study the reaction mechanisms of CF3CH2OCHF2 (HFE‐245fa2; HFE‐245mf) with the OH radicals and Cl atoms. Two hydrogen abstraction channels and two displacement processes are found for each reaction. For further study, the reaction mechanisms of its products (CF3CH2OCF2 and CF3CHOCHF2) and parent ether CH3CH2OCH3 with OH radical are investigated theoretically. The geometries and frequencies of all the stationary points and the minimum energy paths (MEPs) are calculated at the B3LYP/6‐311G(d,p) level. The energetic information along the MEPs is further refined at the G3(MP2) level of theory. For reactions CF3CH2OCHF2 + OH/Cl, the calculation indicates that the hydrogen abstraction from CH2 group is the dominant reaction channel, and the displacement processes may be negligible because of the high barriers. The standard enthalpies of formation for the reactant CF3CH2OCHF2, and two products CF3CH2OCF2 and CF3CHOCHF2 are evaluated via group‐balanced isodesmic reactions. The rate constants of reactions CF3CH2OCHF2 + OH/Cl and CH3CH2OCH3 + OH are estimated by using the variational transition state theory over a wide range of temperature (200–2000 K). The agreement between the theoretical and experimental rate constants is good in the measured temperature range. From the comparison between the rate constants of the reactions CF3CH2OCHF2 and CH3CH2OCH3 with OH, it is shown that the fluorine substitution decreases the reactivity of the CH bond. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Extension of the MST continuum solvation model to the RM1 semiempirical hamiltonian
Authors: Forti Flavio , Barril Xavier , Luque F. Javier , Orozco Modesto 
Published: August 2007

AbstractThe need to simulate large‐sized molecules or to deal with large series of compounds is a challenging topic in computational chemistry, which has stimulated the development of accurate semiempirical methods, such as the recently reported Recife Model 1 (RM1; J Comput Chem 2006, 27, 1101). Even though RM1 may prove to be of value simply due to the enhanced quantitative accuracy in gas phase, it is unclear how the new parameters optimized for RM1 affect the suitability of this semiempirical Hamiltonian to study chemical processes in condensed phases. To address this question, we report the parametrization of the MST/RM1 continuum model for neutral solutes in water, octanol, chloroform and carbon tetrachloride, and for ions in water. The results are used to discuss the transferability of the solvation parameters implemented in previous MST/AM1 and MST/PM3 models. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Finite symmetric graphs with two‐arc transitive quotients II
Authors: Lu Zaiping , Zhou Sanming 
Published: August 2007

AbstractLet $\Gamma$ be a finite G‐symmetric graph whose vertex set admits a nontrivial G‐invariant partition $\cal B$. It was observed that the quotient graph $\Gamma_{\cal B}$ of $\Gamma$ relative to $\cal B$ can be (G, 2)‐arc transitive even if $\Gamma$ itself is not necessarily (G, 2)‐arc transitive. In a previous article of Iranmanesh et al., this observation motivated a study of G‐symmetric graphs ($\Gamma, \cal B$) such that $\Gamma_{\cal B}$ is (G, 2)‐arc transitive and, for blocks B, C ∈ $\cal B$ adjacent in $\Gamma_{\cal B}$, there are exactly |B| − 2(≥1) vertices in B which have neighbors in C. In the present article we investigate the general case where $\Gamma_{\cal B}$ is (G, 2)‐arc transitive and is not multicovered by $\Gamma$ (i.e., at least one vertex in B has no neighbor in C for adjacent B, C ∈ $\cal B$) by analyzing the dual $\cal D^\ast$(B) of the 1‐design $\cal D$(B) ≔ (B, $\Gamma_{\cal B}$(B), I), where $\Gamma_{\cal B}$(B) is the neighborhood of B in $\Gamma_{\cal B}$ and αIC 〈α ∈ B, C ∈  $\Gamma_{\cal B}$(B)〉 in $\cal D$(B) if and only if α has at least one neighbor in C. In this case, a crucial feature is that $\cal D^\ast$(B) admits G as a group of automorphisms acting 2‐transitively on points and transitively on blocks and flags. It is proved that the case when no point of $\cal D$(B) is incident with two blocks can be reduced to multicovers, and the case when no point of $\bar {\cal D}(B)$ is incident with two blocks can be partially reduced to the 3‐arc graph construction, where $\bar {\cal D}(B)$ is the complement of $\cal D$(B). In the general situation, both $\cal D^\ast$(B) and its complement $\bar {{\cal D}^\ast}(B)$ are (G, 2)‐point‐transitive and G‐block‐transitive 2‐designs, and exploring relationships between them and $\Gamma$ is an attractive research direction. In the article we investigate the degenerate case where $\cal D^\ast$(B) or $\bar {{\cal D}^\ast}(B)$ is a trivial Steiner system with block size 2, that is, a complete graph. In each of these cases, we give a construction which produces symmetric graphs with the corresponding properties, and we prove further that every such graph $\Gamma$ can be constructed from $\Gamma_{\cal B}$ by using the construction. © 2007 Wiley Periodicals, Inc. J Graph Theory 56: 167–193, 2007
Fluorine‐18 labelling of small interfering RNAs (siRNAs) for PET imaging
Authors: Viel Thomas , Kuhnast Bertrand , Hinnen Françoise , Boisgard Raphaël , Tavitian Bertrand , Dollé Frédéric 
Published: August 2007

AbstractSmall interfering RNAs (siRNAs), a class of macromolecules constituted by the association of two single‐stranded ribonucleic acids of short sequences, have been labelled with the positron‐emitter fluorine‐18 (T1/2: 109.8 min). The strategy involves (1) prosthetic conjugation of a single‐stranded oligonucleotide with [18F]FPyBrA (N‐[3‐(2‐[18F]fluoropyridin‐3‐yloxy)‐propyl]‐2‐bromoacetamide) followed by (2) formation of the target duplex by annealing with the complementary sequence, therefore, permitting parallel and combinatorial preparation of [18F]siRNAs. Pure fluorine‐18‐labelled siRNAs (0.55–1.11 GBq, specific activity: 74–148 GBq/µmol at EOB) could be obtained within 165 min starting from 37.0 GBq of starting [18F]fluoride (1.5–3.0%, non‐decay‐corrected isolated yields). Copyright © 2007 John Wiley & Sons, Ltd.
From ICI to AstraZeneca: the development of synthetic isotope chemistry at Alderley Park, UK
Authors: Harding John R. 
Published: August 2007

AbstractSynthetic isotope chemistry has played a key role in the discovery and development of candidate drugs for over 40 years at Alderley Park, UK. This review highlights the range of isotopically labelled compounds that have been synthesized and the applications for which they were used. The continually increasing demand for isotopically labelled compounds demonstrates their valuable contribution to the pharmaceutical industry. Copyright © 2007 John Wiley & Sons, Ltd.
Neutral desorption sampling coupled to extractive electrospray ionization mass spectrometry for rapid differentiation of biosamples by metabolomic fingerprinting
Authors: Chen Huanwen , Wortmann Arno , Zenobi Renato 
Published: August 2007

AbstractIt is of increasing interest and practical importance to develop convenient methods based on mass spectrometry for high‐throughput analyses of biological samples. This is usually difficult because of the complex matrix and ion suppression effects. Generation of ions at ambient conditions is a promising solution to these problems because the sample is easily accessible and the ion suppression effect is reduced significantly. A new method for rapid on‐line detection of metabolic markers in complex biological samples is described here. It combines atmospheric pressure desorption sampling by a gentle stream of air or nitrogen with extractive electrospray ionization (EESI) and mass spectrometric analysis. The resulting mass spectral fingerprints are shown to be able to detect spoilage of meat even in the frozen (−20 °C) state and the contamination of spinach by E. coli, and to identify metabolites and contaminants on human skin within seconds, in an on‐line and high‐throughput fashion. Typical molecular markers are identified using MS/MS data and by comparison with reference compounds. Differences between closely related samples are easily visualized by using principal component analysis (PCA) of the mass spectra data. The detection limit achieved is 10 fg/cm2 (S/N = 3) for histamine on the surface of frozen meat. The technique reported here shows potential for more advanced applications in multiple disciplines, including food regulation, homeland security, in vivo metabolomics, and clinical diagnosis. Copyright © 2007 John Wiley & Sons, Ltd.
Frequent detection of cell‐associated HIV‐1 RNA in patients with plasma viral load <50 copies/ml
Authors: Kupfer Bernd , Matz Bertfried , Däumer Martin P. , Roden Fabienne , Rockstroh Jürgen K. , Qurishi Nazifa , Spengler Ulrich , Kaiser Rolf 
Published: August 2007

AbstractDespite prolonged undetectable plasma viral load some HIV‐1 infected patients have been reported to develop resistance‐associated mutations leading to treatment failure. The mechanisms for this phenomenon and the point of origin for residual viral evolution are still not elucidated. In order to quantify cell‐associated HIV‐1 RNA in patients with different levels of plasma viremia paired cell‐associated HIV‐1 RNA loads and plasma viral loads were determined. Weak inverse correlation between these parameters and the amounts of CD4+ T cells was observed, whereas there was no correlation between viral loads and CD8+ T cells or CD14+ monocytes, respectively. In a subset of patients, cell‐associated and plasma HIV‐1 env V3 sequences were analyzed. Plasma viral load and the amount of cell‐associated HIV‐RNA correlated strongly. However, in 62.3% of patients with undetectable plasma viral load cell‐associated HIV‐RNA could be detected. Analyses of HIV‐RNA in plasma and blood cells showed identical sequences in 4/19 patients, whereas the majority of patients had differing HIV‐1 RNA sequences in plasma and cells, respectively. In summary, this study shows that residual viral replication in peripheral blood still occurs in the majority of patients with undetectable plasma viral load. Since these replication events could lead to ongoing viral evolution it should be considered to optimize antiretroviral therapy in order to minimize the development of drug resistance. J. Med. Virol. 79:1440–1445, 2007. © Wiley‐Liss, Inc.
Development and evaluation of a real‐time PCR assay for rapid identification and semi‐quantitation of measles virus
Authors: Thomas Brenda , Beard Stuart , Jin Li , Brown Kevin E. , Brown David W.G. 
Published: August 2007

AbstractA real‐time PCR assay for measles virus was designed and validated using clinical samples including oral fluids, sera, urines, throat swabs, blood samples, and nasopharyngeal aspirates. The test was specific for measles virus, with a slightly higher sensitivity compared to the conventional nested PCR. Calculation of viral genome number in these samples, by comparison with a standard curve prepared from dilutions of cloned measles virus H gene, indicated that, overall, serum samples tended to have a lower viral load than oral fluid samples, and that the viral load decreased with increasing time after onset of symptoms. The real‐time PCR is considered to be a sensitive and specific alternative to the conventional measles PCR, especially in situations where early and rapid diagnosis are important. J. Med. Virol. 79:1587–1592, 2007. © Wiley‐Liss, Inc.
Alpha‐synuclein and its role in metal binding: Relevance to Parkinson's disease
Authors: Wright Josephine A. , Brown David R. 
Published: August 2007

AbstractParkinson's disease and some other neurodegenerative disorders are associated with a protein that can aggregate and form fibrils called alpha‐synuclein. Like many other proteins associated with neurodegenerative disorders, this protein has no known function, and the mechanism by which it could cause diseases is poorly defined. It was recently suggested that it binds copper. This review assesses what is known about alpha‐synuclein and its interaction with metals. © 2007 Wiley‐Liss, Inc.
Loss of synapses in the entorhinal‐dentate gyrus pathway following repeated induction of electroshock seizures in the rat
Authors: Cardoso Armando , Assunção Marco , Andrade José P. , Pereira Pedro A. , Madeira M. Dulce , Paula‐Barbosa Manuel M. , Lukoyanov Nikolai V. 
Published: August 2007

AbstractThe goal of this study was to answer the question of whether repeated administration of electroconvulsive shock (ECS) seizures causes structural changes in the entorhinal‐dentate projection system, whose neurons are known to be particularly vulnerable to seizure activity. Adult rats were administered six ECS seizures, the first five of which were spaced by 24‐hr intervals, whereas the last two were only 2 hr apart. Stereological approaches were employed to compare the total neuronal and synaptic numbers in sham‐ and ECS‐treated rats. Golgi‐stained material was used to analyze dendritic arborizations of the dentate gyrus granule cells. Treatment with ECS produced loss of neurons in the entorhinal layer III and in the hilus of the dentate gyrus. The number of neurons in the entorhinal layer II, which provides the major source of dentate afferents, and in the granular layer of the dentate gyrus, known to receive entorhinal projections, remained unchanged. Despite this, the number of synapses established between the entorhinal layer II neurons and their targets, dentate granule cells, was reduced in ECS‐treated rats. In addition, administration of ECS seizures produced atrophic changes in the dendritic arbors of dentate granule cells. The total volumes of entorhinal layers II, III, and V–VI were also found to be reduced in ECS‐treated rats. By showing that treatment with ECS leads to partial disconnection of the entorhinal cortex and dentate gyrus, these findings shed new light on cellular processes that may underlie structural and functional brain changes induced by brief, generalized seizures. © 2007 Wiley‐Liss, Inc.
The nature and practice of strategic planning in Egypt
Authors: Elbanna Said 
Published: August 2007

Abstract
This paper aims to fill a gap in the literature of strategic management by providing a profile of organizations working in Egypt regarding their practice of strategic planning. Based upon responses from 120 organizations, the respondents have a positive attitude towards strategic planning.
There are relatively few significant differences in the findings between manufacturing and service organizations compared with the differences between local and foreign organizations and also between small and large organizations. Unexpectedly, a high percentage of the respondents are not familiar with some of what are seen as the traditional tools of strategic management.
Copyright © 2007 John Wiley & Sons, Ltd.
The Oil‐Absorbing Property of Polyhydroxyalkanoate Films and its Practical Application: A Refreshing New Outlook for an Old Degrading Material
Authors: Sudesh Kumar , Loo Ching‐Yee , Goh Lay‐Koon , Iwata Tadahisa , Maeda Mizuo 
Published: August 2007

AbstractPolyhydroxyalkanoates (PHAs) have attracted the attention of academia and industry because of their plastic‐like properties and biodegradability. However, practical applications as a commodity material have not materialized because of their high production cost and unsatisfactory mechanical properties. PHAs are also believed to have high‐value applications as an absorbable biomaterial for tissue engineering and drug‐delivery devices because of their biocompatibility. However, research in these areas is still in its very early stages. The main problem faced by proponents of PHAs is the lack of a niche area where PHAs will be the most desired material in terms of its function during use rather than because of its eco‐friendly virtues after use. Here, we report on the oil‐absorbing property of PHA films and its potential applications. By comparing with some of the existing commercial products, the potential application of PHAs as cosmetic oil‐blotting films is revealed for the first time. Besides having the ability to rapidly absorb and retain oil, PHA films also have a natural oil‐indicator property, showing obvious changes in opacity following oil absorption. Surface analysis revealed that the surface structures such as porosity and smoothness exert great influence on the rapid oil‐absorption properties of the PHA films. These newly discovered properties could be exploited to create a niche area for the practical applications of PHAs.magnified image