bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytic study of 2D and 3D grid motion using modified Laplacian
Authors: Burg Clarence
Published: February 2006

The modified Laplacian has been used to move unstructured grids in response to changes in the surface grid for a variety of grid movement applications including store separation, aero‐elastic wing deformation and free surface flow simulations. However, the use of the modified Laplacian can result in elements with negative areas/volumes, because it has no inherent mechanism to prevent inversion of elements. In this paper, the use of a modified Laplacian is studied analytically for a two‐dimensional problem of deforming the inner circle of two concentric circles and for a three‐dimensional problem of deforming the inner sphere of two concentric spheres. By analysing the exact solution for this problem, the amount of translation and deformation of the inner circle that maintains a valid mesh is determined. A general grid movement theorem is presented which determines analytically the maximum allowable deformation before an invalid mesh results. Under certain circumstances, the inner circle and sphere can be expanded until it reaches the outer circle or sphere, while remaining a valid grid, and the inner circle and sphere can be rotated by an extreme amount before failure of the mesh occurs. By choosing the exponent to the modified Laplacian appropriately, extreme deformations for single frequency deformations is possible, although for practical applications where the grid movement has multiple frequencies, choosing the optimal exponent for the modified Laplacian may not be practical or provide much improvement. For grid movement simulations involving rigid body translation and rotation or uniform expansion, the modified Laplacian can yield excellent results, and the optimum choice of the modified Laplacian can be analytically determined for these types of motions, but when there are multiple frequencies in the deformation, the modified Laplacian does not allow much deformation before an invalid grid results. Copyright © 2006 John Wiley & Sons, Ltd.
Adaptive mesh refinement for high‐resolution finite element schemes
Authors: Möller M. , Kuzmin D.
Published: February 2006

New a posteriori error indicators based on edgewise slope‐limiting are presented. The L2‐norm is employed to measure the error of the solution gradient in both global and element sense. A second‐order Newton–Cotes formula is utilized in order to decompose the local gradient error from a 𝒫1 finite element solution into a sum of edge contributions. The slope values at edge midpoints are interpolated from the two adjacent vertices. Traditional techniques to recover (superconvergent) nodal gradient values from consistent finite element slopes are reviewed. The deficiencies of standard smoothing procedures—L2‐projection and the Zienkiewicz–Zhu patch recovery—as applied to nonsmooth solutions are illustrated for simple academic configurations. The recovered gradient values are corrected by applying a slope limiter edge‐by‐edge so as to satisfy geometric constraints. The direct computation of slopes at edge midpoints by means of limited averaging of adjacent gradient values is proposed as an inexpensive alternative. Numerical tests for various solution profiles in one and two space dimensions are presented to demonstrate the potential of this postprocessing procedure as an error indicator. Finally, it is used to perform adaptive mesh refinement for compressible inviscid flow simulations. Copyright © 2006 John Wiley & Sons, Ltd.
Genomic analysis of early adenocarcinoma of the esophagus or gastroesophageal junction: Tumor progression is associated with alteration of 1q and 8p sequences
Authors: van Dekken Herman , Wink Josiane C. , Vissers Kees J. , van Marion Ronald , Koppert Linetta B. , Tilanus Hugo W. , Siersema Peter D. , Tanke Hans J. , Szuhai Karoly , Hop Wim C. J.
Published: February 2006

Early (T1 stage) adenocarcinoma of the esophagus or gastroesophageal junction is a potentially curable disease. We analyzed the genomic spectra of 33 early neoplastic lesions after subdividing the tumors into six depths of invasion (T1–mucosal, m1–m3; T1–submucosal, sm1–sm3). Two subgroups were defined, T1m1–sm1 (n = 18) and T1sm2–sm3 (n = 15). The latter group is associated with frequent lymphatic spread and a high percentage of local and/or distant recurrence. Comparative genomic hybridization with a genomewide 3,500‐element BAC‐PAC array revealed a characteristic gastroesophageal adenocarcinoma pattern of changes, with losses on chromosome arms 4pq, 5q, 8p, 9p, 17p, and 18q and gains on 1q, 6p, 7pq, 11q, 15q, 17q, and 20pq. However, when the two groups were compared, the following BAC clones showed significantly more alterations in the T1sm2–sm3 group: RP11‐534L20 (1q32.1) and RP11‐175A4 (6p21.32), showing gains, and RP11‐356F24, RP11‐433L7, and RP11‐241P12 (all at 8p), showing losses. Gain of RP11‐534L20 (1q32.1) and loss of RP11‐433L7 (8p22) were associated not only with a recurrence‐free period (P = 0.0007 and 0.007, respectively), but also with regional lymphatic dissemination (P = 0.005 and 0.003, respectively). These DNA clones can be considered genomic markers for the aggressive behavior of early esophageal and gastroesophageal junction adenocarcinoma. © 2006 Wiley‐Liss, Inc.
Coherent corticomuscular oscillations originate from primary motor cortex: Evidence from patients with early brain lesions
Authors: Gerloff Christian , Braun Christoph , Staudt Martin , Hegner Yiwen Li , Dichgans Johannes , Krägeloh‐Mann Ingeborg
Published: February 2006

Coherent oscillations of neurons in the primary motor cortex (M1) have been shown to be involved in the corticospinal control of muscle activity. This interaction between M1 and muscle can be measured by the analysis of corticomuscular coherence in the β‐frequency range (β‐CMCoh; 14–30 Hz). Largely based on magnetoencephalographic (MEG) source‐modeling data, it is widely assumed that β‐CMCoh reflects direct coupling between M1 and muscle. Deafferentation is capable of modulating β‐CMCoh, however, and therefore the influence of reafferent somatosensory signaling and corresponding neuronal activity in the somatosensory cortex (S1) has been unclear. We present transcranial magnetic stimulation (TMS) and MEG data from three adult patients suffering from congenital hemiparesis due to pre‐ and perinatally acquired lesions of the pyramidal tract. In these patients, interhemispheric reorganization had resulted in relocation of M1 to the contralesional hemisphere, ipsilateral to the paretic hand, whereas S1 had remained in the lesioned hemisphere. This topographic dichotomy allowed for an unequivocal topographic differentiation of M1 and S1 with MEG (which is not possible if M1 and S1 are directly adjacent within one hemisphere). In all patients, β‐CMCoh originated from the contralesional M1, in accordance with the TMS‐evoked motor responses, and in contrast to the somatosensory evoked fields (SEFs) for which the sources (N20m) were localized in S1 of the lesioned hemisphere. These data provide direct evidence for the concept that β‐CMCoh reflects the motorcortical efferent drive from M1 to the spinal motoneuron pool and muscle. No evidence was found for a relevant contribution of neuronal activity in S1 to β‐CMCoh. Hum Brain Mapp, 2006. © 2006 Wiley‐Liss, Inc.
Fibrosis and disease progression in hepatitis C
Authors: Marcellin Patrick , Asselah Tarik , Boyer Nathalie
Published: February 2006

The progression of fibrosis in chronic hepatitis C determines the ultimate prognosis and thus the need and urgency of therapy. Fibrogenesis is a complex dynamic process, which is mediated by necroinflammation and activation of stellate cells. The liver biopsy remains the gold standard to assess fibrosis. Scoring systems allow a semiquantitative assessment and are useful for cross-sectional and cohort studies and in treatment trials. The rate at which fibrosis progresses varies markedly between patients. The major factors known to be associated with fibrosis progression are older age at infection, male gender, and excessive alcohol consumption. Viral load and genotype do not seem to influence significantly the progression rate. Progression of fibrosis is more rapid in immunocompromised patients. Hepatic steatosis, obesity, and diabetes may also contribute to more rapid progression of fibrosis. There are no tests that reliably predict the rate of progression of fibrosis in an individual patient. High serum alanine aminotransferase (ALT) levels are associated with a higher risk of fibrosis progression, and worsening of fibrosis is uncommon in patients with persistently normal serum aminotransferase levels. Serum markers for fibrosis are not reliable and need to be improved and validated. Liver biopsy provides the most accurate information on the stage of fibrosis and grade of necroinflammation, both of which have prognostic significance. Repeating the liver biopsy, 3 to 5 years after an initial biopsy is the most accurate means of assessing the progression of fibrosis. (Hepatology 2002;36:S47-S56).
Noninvasive monitoring of patients with chronic hepatitis C
Authors: Fontana Robert J. , Lok Anna S. F.
Published: February 2006

Hepatic fibrosis is the main determinant of clinical outcomes of chronic hepatitis C. Liver histology is frequently considered the gold standard for assessing hepatic fibrosis. However, liver biopsy is associated with sampling error, interobserver variability, and potential complications. Thus, there is a need for simple, inexpensive, and reliable noninvasive means to assess disease severity in patients with chronic hepatitis C. Clinical examination is unreliable in differentiating different stages of compensated liver disease. Among the routine laboratory tests, decreased platelet count, increase in the ratio of aspartate to alanine aminotransferase (AST/ALT), and prolonged prothrombin time are the earliest indicators of cirrhosis and portal hypertension. Individual serum fibrosis markers have limited accuracy in predicting hepatic fibrosis. Indices composed of a panel of markers correlate better with histological fibrosis, but their reliability requires further validation. Currently, noninvasive monitoring of patients with chronic hepatitis C relies on clinical evaluation, routine laboratory tests, and ultrasound and endoscopic surveillance in patients with cirrhosis. Initial evaluation should focus on assessment of activity and stage of liver disease for prognostication and decisions regarding treatment, and to rule out coinfections and other causes of liver disease. Subsequent follow-up should focus on detection of liver disease progression and the need for treatment. The frequency of monitoring and the tests used will depend on the patient’s age, stage of liver disease, and comorbid conditions. There is an urgent need to develop and validate noninvasive tests that can accurately reflect the full spectrum of hepatic inflammation and fibrosis in chronic hepatitis C. (Hepatology 2002;36:S57-S64).
Prevention of spread of hepatitis C
Authors: Alter Miriam J.
Published: February 2006

Hepatitis C virus (HCV) is transmitted by percutaneous or permucosal exposure to infectious blood or blood-derived body fluids. Based on the results of cohort and acute case control studies, risk factors associated with acquiring HCV infection in the United States have included transfusion of blood and blood products and transplantation of solid organs from infected donors, injecting drug use, occupational exposure to blood (primarily contaminated needle sticks), birth to an infected mother, sex with an infected partner, and multiple heterosexual partners. Nosocomial and iatrogenic transmission of HCV primarily are recognized in the context of outbreaks, and primarily have resulted from unsafe injection practices. Transmission from HCV-infected health care workers to patients is rare. Transfusions and transplants have been virtually eliminated as sources for transmission, and most (68%) newly acquired cases of hepatitis C are related to injecting drug use. The primary prevention of illegal drug injecting will eliminate the greatest risk factor for HCV infection in the United States. Other prevention strategies that need to be widely implemented include risk reduction counseling and services and review and improvement of infection control practices in all types of health care settings. Testing for HCV infection should be routinely performed for persons at high risk for infection or who require postexposure management. There are no recommendations for routine restriction of professional activities for HCV-infected health care workers, and persons should not be excluded from work, school, play, and child care or other settings on the basis of their HCV infection status. (Hepatology 2002;36:S93-S98).
Monitoring of viral levels during therapy of hepatitis C
Authors: Davis Gary L.
Published: February 2006

Alpha interferon therapy of chronic hepatitis C is typically accompanied by a biphasic decrease in hepatitis C virus (HCV) RNA levels: an initial rapid decline during the first 24 to 48 hours, and a second more gradual decline during the following weeks. The rate of second-phase decline correlates with ultimate response to interferon treatment. Thus, assessment of early virological response (EVR) may predict outcome. Data from 2 large clinical trials of peginterferon and ribavirin were combined and analyzed to determine the optimal definition of an EVR which, if not achieved, was associated with a low likelihood of a sustained virological response (SVR). A fall in HCV RNA level to undetectable or by at least 2 log10 units after 12 weeks was found to be the optimal definition of an EVR. Among 965 patients, 778 (80%) achieved an EVR by week 12, including all except 1 patient with genotypes 2 or 3. Among 187 patients without an EVR, only 3 (1.6%) had an SVR. These findings suggest that patients with genotype 1 who do not achieve an EVR should stop treatment after 12 weeks. Use of an early stopping rule reduces treatment costs by at least 16% and avoids the inconvenience and side effects of treatment in the 19% of patients without an EVR who have little chance of a lasting virological response.
Treatment of patients with hepatitis C and normal serum aminotransferase levels
Authors: Bacon Bruce R.
Published: February 2006

Approximately 30% of patients with chronic hepatitis C have normal serum alanine aminotransferase (ALT) levels and another 40% have ALT levels that are less than twice the upper limit of the normal range. Most patients with normal ALT levels have mild degrees of inflammation with mild or no fibrosis, and the rate of disease progression is reduced compared with that in patients with elevated ALT levels. Some patients with normal ALT levels have advanced fibrosis and cirrhosis on liver biopsy. Treatment of patients with normal ALT levels with either interferon monotherapy or interferon/ribavirin combination therapy has shown sustained virological response (SVR) rates that are equivalent to those achieved for patients with elevated ALT levels. Thus, patients with chronic hepatitis C should not be excluded from therapy based on ALT levels alone. The decision to initiate therapy with interferon and ribavirin should be based on a combination of factors independent of ALT levels including amount of fibrosis on liver biopsy, hepatitis C virus (HCV) genotype and viral level, patient age and motivation, and co-morbid illness, and the presence of other complicating conditions. (Hepatology 2002;36:S179-S184).
Role of MSK1 in the signaling pathway leading to VEGF‐mediated PAF synthesis in endothelial cells
Authors: Marchand Catherine , Favier Judith , Sirois Martin G.
Published: February 2006

Vascular endothelial growth factor (VEGF) inflammatory effects require acute platelet‐activating factor (PAF) synthesis by endothelial cells (EC). We previously reported that VEGF‐mediated PAF synthesis involves the activation of VEGF receptor‐2/Neuropilin‐1 complex, which is leading to the activation of p38 and p42/44 mitogen‐activated protein kinases (MAPKs) and group V secretory phospholipase A2 (sPLA2‐V). As the mechanisms regulating sPLA2‐V remain unknown, we addressed the role of the mitogen‐ and stress‐activated protein kinase‐1 (MSK1), which can be rapidly and transiently activated by p38 or p42/44 MAPKs. In native bovine aortic endothelial cells (BAEC), we observed a constitutive protein interaction of MSK1 with p38, p42/44 MAPKs, and sPLA2‐V. These protein interactions were maintained in BAEC transfected either with the empty vector pCDNA3.1, wild‐type MSK1 (MSK1‐WT) or N‐terminal dead kinase MSK1 mutant (MSK1‐D195A). However, in BAEC expressing C‐terminal dead kinase MSK1 mutant (MSK1‐D565A), the interaction between MSK1 and sPLA2‐V was reduced by 82% and 90% under basal and VEGF‐treated conditions as compared to native BAEC. Treatment with VEGF for 15 min increased basal PAF synthesis in native BAEC, pCDNA3.1, MSK1‐WT, and MSK1‐D195A by 166%, 139%, 125%, and 82%, respectively. In contrast, PAF synthesis was prevented in cells expressing MSK1‐D565A mutant. These results demonstrate the essential role of the C‐terminal domain of MSK1 for its constitutive interaction with sPLA2‐V, which appears essential to support VEGF‐mediated PAF synthesis. J. Cell. Biochem. 98: 1095–1105, 2006. © 2006 Wiley‐Liss, Inc.
Radical reaction C3H+NO: A mechanistic study
Authors: Xie Hong‐Bin , Ding Yi‐Hong , Sun Chia‐Chung
Published: February 2006

Although a number of hydrocarbon radicals including the heavier C3‐radicals C3H3 and C3H5 have been experimentally shown to deplete NO effectively, no theoretical or experimental attempts have been made on the reactivity of the simplest C3‐radical towards NO. In this article, we report our detailed mechanistic study on the C3H+NO reaction at the Gussian‐3//B3LYP/6‐31G(d) level by constructing the singlet and triplet electronic state [H,C3,N,O] potential energy surfaces (PESs). The l‐C3H+NO reaction is shown to barrierlessly form the entrance isomer HCCCNO followed by the direct O‐elimination leading to HCCCN+3O on triplet PES, or by successive O‐transfer, N‐insertion, and CN bond‐rupture to generate the product 1HCCN+CO on singlet PES. The possible singlet–triplet intersystem crossings are also discussed. Thus, the novel reaction l‐C3H+NO can proceed effectively even at low temperatures and is expected to play an important role in both combustion and interstellar processes. For the c‐C3H+NO reaction, the initially formed HcCCCNO can most favorably isomerize to HCCCNO, and further evolution follows that of the l‐C3H+NO reaction. Quantitatively, the c‐C3H+NO reaction can take place barrierlessly on singlet PES, yet it faces a small barrier 2.7 kcal/mol on triplet PES. The results will enrich our understanding of the chemistry of the simplest C3‐radical in both combustion and interstellar processes, which to date have received little attention despite their importance and available abundant studies on its structural and spectroscopic properties. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 641–660, 2006
Synthesis of the 15N‐labelled insecticide imidacloprid
Authors: Schippers Nicole , Schwack Wolfgang
Published: February 2006

A five‐step synthesis of the neonicotinoid insecticide imidacloprid (1) labelled with 15N is reported in an overall yield of 10%. The stable isotope 15N was introduced in the pyridine part by reaction of 15NH3 with coumalic acid methyl ester (2) to 15N‐hydroxy nicotinic acid (3) followed by further reactions to 15N‐2‐chloro‐5‐(chloromethyl) pyridine (6) which was coupled with N‐nitroimidazolidin‐2‐imine to yield 1. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of diffusion‐weighted imaging for the differential diagnosis of poorly contrast‐enhanced and T2‐prolonged bone masses: Initial experience
Authors: Hayashida Yoshiko , Hirai Toshinori , Yakushiji Toshitake , Katahira Kazuhiro , Shimomura Osamu , Imuta Masanori , Nakaura Takeshi , Utsunomiya Daisuke , Awai Kazuo , Yamashita Yasuyuki
Published: February 2006

Purpose

To determine whether quantitative diffusion‐weighted imaging (DWI) is useful for characterizing poorly contrast‐enhanced and T2‐prolonged bone masses.

Materials and Methods

We studied 20 bone masses that showed high signal intensity on T2‐weighted images and poor enhancement on contrast‐enhanced T1‐weighted images. These included eight solitary bone cysts, five fibrous dysplasias, and seven chondrosarcomas. To analyze diffusion changes we calculated the apparent diffusion coefficient (ADC) for each lesion.

Results

The ADC values of the two types of benign lesions and chondrosarcomas were not significantly different. However, the mean ADC value of solitary bone cysts (mean ±SD, 2.57 ± 0.13 × 10–3 mm2/second) was significantly higher than that of fibrous dysplasias and chondrosarcomas (2.0 ± 0.21 × 10–3 mm2/second and 2.29 ± 0.14 × 10–3 mm2/second, respectively, P < 0.05). None of the lesions with ADC values lower than 2.0 × 10–3 mm2/second were chondrosarcomas.

Conclusion

Although there was some overlapping in the ADC values of chondrosarcomas, solitary bone cyst, and fibrous dysplasia, quantitative DWI may aid in the differential diagnosis of poorly contrast‐enhanced and T2‐prolonged bone masses. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
AT&T adds business continuity to the long list of telework's advantages
Authors: Roitz Joseph , Jackson Ellen
Published: February 2006

AT&T's experience in making telework an essential part of its organizational strategy can serve as a model for other knowledge‐based companies looking for new sources of competitive advantage. The promises of telework—reduced real estate costs, productivity gains, higher employee satisfaction and retention—have materialized as measurable returns for AT&T. Hurricane Katrina provided just the latest evidence of another important telework contribution, business continuity, with sizable benefits for the company, its customers, and its employees. © 2006 Wiley Periodicals, Inc.
Beyond knowledge sharing: the management of transactive knowledge systems
Authors: Brauner Elisabeth , Becker Albrecht
Published: February 2006

Most approaches to organizational learning and knowledge management concentrate on implicit and shared knowledge as basis for organizational competencies and competitive advantage. In this paper we argue that it is explicit and unshared expertise rather than implicit and shared knowledge which is valuable for organizations. We ground our argument in a psychological concept of personal knowledge held by individuals and on the theory of transactive knowledge systems, which accounts for the social integration of individual knowledge. Transactive knowledge systems as webs of knowledge about knowledge are the core of organizational knowledge. We discuss challenges for knowledge management derived from this view, namely the requirement to view knowledge management as a social interactive process. Furthermore, conclusions concerning the role of information technology and human resource management are drawn. Copyright © 2006 John Wiley & Sons, Ltd.
Competence transfer from old timers to newcomers analysed with the help of the holistic concept of man
Authors: Koskinen Kaj U. , Pihlanto Pekka
Published: February 2006

This conceptual article addresses the question of how the competencies of old timers are transferred to newcomers in the context of a technology company. First, an individual's personal competence which is divided into knowledge based competencies and socially based competencies is illustrated. A special focus is on how the competence alters in the course of the individual's working life. Second, our conceptual tool the ‘Holistic Concept of Man’, which defines the human individual to consist of three deeply intertwined modes of existence (i.e.consciousness,situationalityandcorporeality), is described. Third, because in the literature thecommunicabilityandmotivationare often identified as factors that facilitate or hinder competence transfer, these factors are analysed by the tool mentioned. However, because the competence is, in fact, transferred from the worldview of an old timer to the worldview of a newcomer, this concept is described before the analysis. Also the notion of communicability is divided further and handled in three different sub‐sections dealing with: straight interaction between an old timer and a newcomer, action learning, and workplace learning. The paper ends with the conclusion that when studying and analysing competence transfer in practice, three individual dimensions (i.e. consciousness, situationality and corporeality) should be understood and taken into consideration. It is also concluded that old timers' and newcomers' different worldviews and different situationalities are the central reasons for difficulties in the competence transferring process between these parties. Copyright © 2006 John Wiley & Sons, Ltd.
Cortical atrophy in the cerebellar variant of multiple system atrophy: A voxel‐based morphometry study
Authors: Brenneis Christian , Boesch Sylvia M. , Egger Karl E. , Seppi Klaus , Scherfler Christoph , Schocke Michael , Wenning Gregor K. , Poewe Werner
Published: February 2006

This study aimed to determine in vivo the atrophy patterns in clinically established cerebellar variant of multiple‐system atrophy (MSA‐C) using voxel‐based morphometry (VBM). Thirteen patients with MSA‐C (12 probable, 1 possible) and 13 healthy controls matched for age and sex were included. High‐resolution MR images were acquired with a 1.5 T scanner. Images were normalized onto a study‐specific template, segmented into the tissue compartments, modulated with the Jacobian determinants, and finally smoothed with a Gaussian kernel filter of 10 mm. The general linear model was used to assess statistical differences in gray and white matter. Infratentorial atrophy was observed in the cerebellar hemispheres, vermis, mesencephalon, and pons of MSA‐C patients. Supratentorial volume loss was found in orbitofrontal and mid‐frontal regions as well as in temporomesial and insular areas of both hemispheres. A negative correlation was observed between a cerebellar ataxia score and the volume of cerebellar hemispheres, peduncles, and pons. To compare this atrophy pattern to that of spinocerebellar ataxia (SCA2), which was previously reported by our group, a conjunction analysis was assessed. We observed a volume loss shared by both disorders comprising the cerebellum, vermis, pons, mesencephalon, orbitofrontal, mid‐frontal, and temporomesial cortex of both hemispheres as well as the left insular cortex. © 2005 Movement Disorder Society
Solid‐state NMR investigation of sodium nucleotide complexes
Authors: Grant Christopher V. , McElheny Dan , Frydman Veronica , Frydman Lucio
Published: February 2006

Solid‐state NMR has been used to analyze the chemical environments of sodium sites in powdered crystalline samples of sodium nucleotide complexes. Three of the studied complexes have been previously characterized structurally by crystallography (disodium deoxycytidine‐5′‐monophosphate heptahydrate, disodium deoxyuridine‐5′‐monophosphate pentahydrate and disodium adensoine‐5′‐triphosphate trihydrate). For these salts, the nuclear quadrupole coupling parameters measured by 23Na multiple‐quantum magic‐angle‐spinning NMR could be readily correlated with sodium ion coordination environments. Furthermore, two complexes that had not been previously characterized structurally, disodium uridine‐3′‐monophosphate and a disodium uridine‐3′‐monophosphate/disodium uridine‐2′‐monophosphate mix, were identified by solid‐state NMR. A spectroscopic assignment of the four sites of an additional salt, disodium adensoine‐5′‐triphosphate trihydrate, is also presented and discussed within the context of creating a general approach for the spectroscopic assignment of multiple sites in sodium nucleotide complexes. Copyright © 2006 John Wiley & Sons, Ltd.
Solid‐state 207Pb NMR studies of lead‐group 16 and mixed transition‐metal/lead‐group 16 element‐containing materials
Authors: Van Bramer S. E. , Glatfelter A. , Bai S. , Dybowski C. , Neue G. , Perry D. L.
Published: February 2006

207Pb solid‐state NMR studies have been conducted on binary lead‐group 16 and mixed transition‐metal/lead group 16 materials, correlating the NMR chemical shifts of the materials with their structures. The experimental results show that the 207Pb chemical shifts are strongly influenced by the local electronic structure. Data are reported for lead selenide, lead selenate, calcium plumbate, strontium plumbite, barium plumbite, lead borate, lead zirconate, lead tungstate, lead meta‐tantalate, lead niobate, lead molybdate, lead meta‐vanadate, lead sulfite, and lead sulfate. Copyright © 2006 John Wiley & Sons, Ltd.
Revisiting the calculation of 13C chemical shift tensors in cadmium acetate dihydrate with EIM and EIM/cluster methods
Authors: Orendt Anita M.
Published: February 2006

The chemical shift tensors of the acetate anions in cadmium acetate dihydrate are calculated using a cluster approach, the embedded ion method (EIM), and a combination of the two in the EIM/cluster method. The results of these calculations are compared with those completed on the isolated acetate anion and show the need for the inclusion of intermolecular interactions. The RMS difference between experiment and theory improves from over 60 ppm when the calculation is completed on an isolated anion, to below 10 ppm when interactions to nearby atoms are included. The best cluster model includes three cadmium acetate dihydrate and gives an RMS result of 4.4 ppm. The EIM method, which uses point charges to account for the intermolecular effects, achieves an RMS of 7.7 ppm on individual anions alone. A combination of the two, the EIM/cluster method, shows that the only necessary atom to explicitly add is the nearest cadmium; this addition results in an RMS of 4.1 ppm. These results are also discussed in terms of the computational cost of the different calculations. Copyright © 2006 John Wiley & Sons, Ltd.
Intermolecular shielding from molecular magnetic susceptibility. A new view of intermolecular ring current effects
Authors: Facelli Julio C.
Published: February 2006

This paper presents calculations of the NICS (nuclear independent chemical shieldings) in a rectangular grid surrounding the molecules of benzene, naphthalene and coronene. Using the relationship between calculated NICS and the induced magnetic field, the calculated NICS are used to predict intermolecular effects due to molecular magnetic susceptibility or ring current effects. As expected from approximate ring current models, these intermolecular shielding effects are concentrated along the direction perpendicular to the molecular plane and they approach asymptotically to a dipolar functional dependence, i.e. (1–3 cos2θ)/r3). The deviations from the dipolar functional form require that the calculations of these intermolecular effects be done using a suitable interpolation scheme of the NICS calculated on the grid. The analysis of the NICS tensor components shows that these intermolecular shielding effects should be primarily expected on shielding components of the neighboring molecules nuclei, which are perpendicular to the molecular plane of the aromatic compound generating the induced field. The analysis of the calculated NICS along the series benzene, naphthalene and coronene shows that these intermolecular effects increase monotonically with the number of aromatic rings. Copyright © 2006 John Wiley & Sons, Ltd.
Aggressive and nonaggressive rejected students: An analysis of their differences
Authors: López Estefanía Estévez , Olaizola Juan Herrero , Ferrer Belén Martínez , Ochoa Gonzalo Musitu
Published: February 2006

The present study aimed to analyze differences between aggressive and nonaggressive rejected students in four sets of variables: personal, family, school, and social. Participants in the study were 843 Spanish adolescents ranging in age from 11 to 16 years old, of whom 47% were boys. Results indicated that these two subgroups of rejected students show a different profile. Aggressive rejected students informed of lower levels of family self‐esteem, less parental support, higher levels of aggression between their parents at home, and a more offensive parent–child communication in comparison with nonaggressive rejected adolescents. Moreover, aggressive rejected students showed lower levels of academic self‐esteem, a more negative attitude toward school and studies, poorer relationships with teachers, and more academic difficulties than did adolescents in the nonaggressive rejected subgroup. Finally, aggressive rejected students indicated the presence of more undesirable life events and changes in their lives and, in general, higher levels of perceived stress. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 387–400, 2006.
Effect of body mass index on response to methacholine bronchial provocation in healthy and asthmatic adolescents
Authors: Mansell Anthony L. , Walders Natalie , Wamboldt Marianne Z. , Carter Rick , Steele Dale W. , Devin Jerilyn A. , Monica Taylor H. , Miller Alison L. , Wamboldt Frederick S.
Published: February 2006

A linkage between airway hyperreactivity and obesity could partly explain the prevalence of obesity in asthmatics. To test for such a linkage, we analyzed body mass index (BMI), pulmonary function, methacholine bronchial provocation, and asthma severity scores in 216 adolescents (aged 12–18 years), of whom 82 were healthy and 134 were asthmatic. Methacholine provocations in a subgroup of 36 subjects (healthy and asthmatic) enabled us to examine the effects of BMI on dynamic hyperinflation and ventilatory indices during induced bronchospasm. Age‐ and gender‐specific BMI was higher in asthmatics (74 ± 24%) compared to healthy subjects (61 ± 28%, P < 0.002). General linear model analysis, in which baseline spirometric results were adjusted for gender, age, race, and height, showed opposing effects of BMI on expiratory flow in controls and asthmatics (P < 0.05), i.e., forced expired volume in 1 sec increased with BMI in controls (P < 0.02), but forced expiratory flow (FEF)25–75% decreased with BMI in asthmatics (P < 0.05). However, linear regression analysis showed no effect of BMI on the provocation dose for methacholine (PD20) in either controls or asthmatics, and there was no effect of BMI on asthma severity scores. Overweight (BMI >85th percentile) and nonoverweight subjects had similar degrees of dynamic hyperinflation during positive provocations, but overweight subjects had greater decreases in mean inspiratory flow (mean, 28% vs. 9%, P < 0.05). We conclude that our measurements support a relationship between overweight and baseline flow limitation, rather than a relationship between overweight and airways hyperreactivity, in the linkage between overweight and asthma during adolescence. Pediatr Pulmonol. 2006; 41:434–440. © 2006 Wiley‐Liss, Inc.
Functional grouping based on signatures in protein termini
Authors: Bahir Iris , Linial Michal
Published: February 2006

The two ends of each protein are known as the amino (N‐) and carboxyl (C‐) termini. Short signatures in a protein's termini often carry vital cellular function. No systematic research has been conducted to address the importance of short signatures (3 to 10 amino acids) in protein termini at the proteomic level. Specifically, it is unknown whether such signatures are evolutionarily conserved, and if so, whether this conservation confers shared biological functions. Current signature detection methods fail to detect such short signatures due to inadequate statistical scores. The findings presented in this study strongly support the notion that functional significance of protein sets may be captured by short signatures at their termini. A positional search method was applied to over one million proteins from the UniProt database. The result is a collection of about a thousand significant signature groups (SIGs) that include previously identified as well as many novel signatures in protein termini. These SIGs represent protein sets with minimal or no overall sequence similarity excepting the similarity at their termini. The most significant SIGs are assigned by their strong correspondence to functional annotations derived from external databases such as Gene Ontology. Each of the SIGs is associated with the statistical significance of its functional association. These SIGs provide a valuable source for testing previously overlooked signatures in protein termini and allow for the investigation of the role played by such signatures throughout evolution. The SIGs archive and advanced search options are available at http://www.proteus.cs.huji.ac.il. Proteins 2006. © 2006 Wiley‐Liss, Inc.
The effect of cone voltage on electrospray mass spectra of the bisquaternary ammonium salt decamethoxinum
Authors: Pashynska V. A. , Kosevich M. V. , Heuvel H. Van den , Claeys M.
Published: February 2006

The effect of cone voltage (CV) variation on the mass spectral pattern of the bisquaternary ammonium salt decamethoxinum in the electrospray ionization (ESI) mode was studied. The advantage of decamethoxinum as a test compound in ESI mass spectrometry lies in the production of two types of precursor ions, i.e. the doubly charged organic dication Cat2+ and its singly charged cluster with a Cl− counterion, Cat · Cl+. This makes it possible to monitor the fragmentation patterns of these ions under identical experimental conditions. Pronounced qualitative and quantitative changes in the ESI mass spectra were observed upon a gradual increase of the CV. The model compound decamethoxinum allowed us to reveal the extreme situation, in which the mass spectra at a CV below and over approximately 100 V look quite different, in that they contain different product ions of Cat2+ and Cat · Cl+. While this effect may be much less pronounced for other classes of organic compounds, it should be properly taken into account for the adequate description of fragmentation pathways of bisquaternary ammonium compounds with ESI. Comparison of ESI, FAB‐SIMS and MALDI mass spectra of decamethoxinum shows that taking into account CV effects also permits us to gain information on energy deposition into ions generated with the different ionization techniques. Copyright © 2006 John Wiley & Sons, Ltd.
Generation of regiospecific carbanions under electrospray ionisation conditions and their selectivity in ion‐molecule reactions with CO2
Authors: Kumar M. Kiran , Sateesh B. , Prabhakar S. , Sastry G. Narahari , Vairamani M.
Published: February 2006

Regiospecific formation of carbanions from a set of geometrical (cis and trans isomers) and five different sets of positional isomers (ortho, meta and para isomers) of aromatic carboxylic acids is reported under negative electrospray ionisation conditions by decarboxylation of the carboxylate anions. The structures of decarboxylated anions, [(M–H)–CO2]−, are studied by ion‐molecule reactions with carbon dioxide in the collision cell of a triple quadrupole mass spectrometer. The [(M–H)–CO2]− ions generated from the trans and meta/para isomers react with CO2 to produce product ions corresponding to the addition of one CO2, which confirms the survival of the [(M–H)–CO2]− ions as carbanions. On the other hand, the [(M–H)–CO2]− ions generated from cis and ortho isomers failed to react with CO2 due to rapid isomerisation of the initially generated carbanion to a aromatic carboxylate/oxide anion, which is unreactive with CO2, through a facile intramolecular proton transfer from the proton‐containing substituent to the carbanion site. When the experiments were performed at high desolvation temperatures (300°C), instead of 100°C, the relative abundance of [(M–H)–CO2]− ions and the corresponding CO2 adduct in ion‐molecule reaction experiments increased significantly due to minimisation of proton exchange. Quantum chemical calculations on some of the generated isomeric carbanions and their isomerised products due to proton transfer support the selective stability of carbanions. Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of curcuminoids by positive and negative electrospray ionization and tandem mass spectrometry
Authors: Jiang Hongliang , Somogyi Árpád , Jacobsen Neil E. , Timmermann Barbara N. , Gang David R.
Published: February 2006

The curcuminoids are a group of diarylheptanoid molecules that possess important pharmacological activities, particularly acting as anti‐inflammatory agents. The main purpose of this study was to investigate the fragmentation behavior of the three major curcuminoids in ion trap liquid chromatography/tandem mass spectrometry (LC/MS/MS). Both positive and negative mode electrospray ionization in tandem and multidimensional MSn experiments in quadrupole ion trap instruments and high‐resolution and accurate mass MS and sustained off‐resonance irradiation (SORI) MS/MS experiments in a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer were used to elucidate the main fragmentation channels of these compounds. These experiments yielded essentially the same fragmentation results in both ion trap and ICR instruments for all three curcuminoids and for their phenolic monoacetates. Major and diagnostic fragment ions were identified and their origins are proposed. Copyright © 2006 John Wiley & Sons, Ltd.
The biotic and abiotic legacy of a large infrequent flood disturbance in the Sabie River, South Africa
Authors: Parsons Melissa , McLoughlin Craig A. , Rountree Mark W. , Rogers Kevin H.
Published: February 2006

Large infrequent disturbances (LIDs) leave heterogeneous, patchy legacies because the event may have different severities in different locations, or may influence ecosystem components differently. Biotic and abiotic legacies form the template upon which subsequent ecological processes take place and thus, LIDs can have a long‐lasting influence on ecosystems. This study determined the geomorphological (channel type), landscape state (mosaic of physical and riparian vegetation patches) and riparian vegetation legacies of an extreme flood in the Sabie River. The linear proportions of geomorphological channel types were altered by the flood because of complex patterns of sediment erosion and deposition related to bed slope and channel width. Biotic landscape states (tree, shrub, reed, herbaceous vegetation) were stripped to expose the underlying physical template. The persistence and arrangement of landscape states varied amongst channel types because of the interaction between flood flows and the geomorphological attributes of each channel type. Overall, some riparian species decreased in density because of removal by the flood, and some increased in density because of post‐flood recruitment or re‐establishment. The flood also changed the location of many species in relation to their characteristic pre‐flood elevation within the channel. In accordance with the expectations of LIDs, the effects of the flood were not uniform. Instead, the flood left a legacy of juxtaposed biotic and abiotic components that varied spatially amongst channel types and at different elevations within the channel. Copyright © 2006 John Wiley & Sons, Ltd.
Hydro‐climatic and land use changes in the River Lune catchment, North West England, implications for catchment management
Authors: Orr H. G. , Carling P. A.
Published: February 2006

Reported trends across the British Isles, illustrate changing rainfall gradients. Northern areas have become wetter in recent decades with greater variation between NW and SE rainfall totals. This paper explores hydro‐climatic changes in North‐West England over the last 140 years as part of a whole catchment investigation into the nature and causes of change in fluvial geomorphology. Variability in runoff in the Lune catchment is explained in terms of observed climate and land use changes; implications for river and catchment management are discussed.

Area average annual rainfall in the North‐West of England show no clear trend over the last 100 years although rain gauges at higher altitudes appear to show increased totals. Over the last 30 years changes in the seasonality of rainfall have been observed. A greater proportion of annual rainfall has occurred in the winter half‐year and an increased frequency of wet‐days has been linked to catchment‐scale flooding. More rain falling on upland areas (> 300 m) has resulted in more rapid runoff from these areas enhanced by land use practices—specifically in heavily grazed hills with a short vegetation cover. The result is a highly varied runoff response within the catchment with localized increases in stream power and the potential for geomorphic change. This effect is ‘damped’ lower down the catchment highlighting the importance of within catchment variability and the need to conduct hydrological analysis at smaller than whole catchment scales. These findings have important implications for water resources, in particular: water storage within catchments; changes in the duration and frequency of floods and droughts; mobilization of sediment; erosion; channel and flood risk management; and ecological function. Copyright © 2006 John Wiley & Sons, Ltd.
Predicting case numbers during infectious disease outbreaks when some cases are undiagnosed
Authors: Glass K. , Becker N. , Clements M.
Published: February 2006

We describe a method for calculating 95 per cent bounds for the current number of hidden cases and the future number of diagnosed cases during an outbreak of an infectious disease. A Bayesian Markov chain Monte Carlo approach is used to fit a model of infectious disease transmission that takes account of undiagnosed cases. Assessing this method on simulated data, we find that it provides conservative 95 per cent bounds for the number of undiagnosed cases and future case numbers, and that these bounds are robust to modifications in the assumptions generating the simulated data. Moreover, the method provides a good estimate of the initial reproduction number, and the reproduction number in the latter stages of the outbreak. Applying the approach to SARS data from Hong Kong, Singapore, Taiwan and Canada, the bounds on future diagnosed cases are found to be reliable, and the bounds on hidden cases suggests that there were few hidden cases remaining at the end of the outbreaks in each region. We estimate that the initial reproduction numbers lay between 1.5 and 3, and the reproduction numbers in the later stages of the outbreak lay between 0.36 and 0.6. Copyright © 2006 John Wiley & Sons, Ltd.
Dramatic Effect of Dispersed Carbon Nanotubes on the Mechanical and Electroconductive Properties of Polymers Derived from Ionic Liquids
Authors: Fukushima Takanori , Kosaka Atsuko , Yamamoto Yohei , Aimiya Takuji , Notazawa Shunsuke , Takigawa Toshikazu , Inabe Tamotsu , Aida Takuzo
Published: February 2006

Free‐radical polymerization of an imidazolium ion‐based ionic liquid bearing a methacrylate group, gelling with single‐walled carbon nanotubes (SWNTs), allows fabrication of a mechanically reinforced, electroconductive soft material (bucky plastic). A film sample of this material displays an excellent conductivity of 1 S cm−1 and a 120‐fold enhancement of the Young’s modulus at a 7 wt % content of SWNTs. The conductivity is temperature‐dependent in the range 5–300 K, suggesting that the conductive process involves carrier hopping. Scanning electron and atomic force micrographs of a bucky plastic film display the presence of crosslinked networks consisting of finely dispersed SWNTs. Such nanotube networks, developed in the polymer matrix, likely suppress slipping of entrapped polymer molecules via a strong interfacial interaction and also facilitate intertubular carrier transport. Although a bucky plastic derived from a vinylimidazolium ion‐based ionic liquid monomer shows a comparable conductivity to that of the methacrylate version, the film is brittle irrespective of the presence or absence of SWNTs.