bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trigonal pyramidal carbon geometry as model for electrophilic addition–substitution and elimination reactions and its significance in enzymatic processes
Authors: Buck Henk M. 
Published: August 2006

AbstractVarious examples are given in which compounds are characterized as products or intermediates in a (distorted) trigonal pyramidal (TP) geometry. These observations have taken place mainly in the field of carbocation chemistry. Special attention is given to carbenium ions formed by halogen addition to 1,1‐diarylsubstituted ethylenes focused on the electronic effects of the C‐halogen bond as axial bond in a TP geometry with regard to the π‐distribution in the rest of the molecular system. The experimental verification is accompanied by quantum chemical calculations. We also used the TP structure as a reactive model for specific enzymatic reactions. The relevance of this geometry is shown for the dehalogenation reaction of the nucleophilic displacement in dichloroethane catalyzed by haloalkane dehalogenase and for the decarboxylation of L‐ornithine with ornithine decarboxylase under loss of carbon dioxide. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Molecular dynamics simulations of polarizable DNA in crystal environment
Authors: Babin Volodymyr , Baucom Jason , Darden Thomas A. , Sagui Celeste 
Published: August 2006

AbstractWe have investigated the role of the electrostatic description and cell environment in molecular dynamics (MD) simulations of DNA. Multiple unrestrained MD simulations of the DNA duplex d(CCAACGTTGG)2 have been carried out using two different force fields: a traditional description based on atomic point charges and a polarizable force field. For the time scales probed, and given the “right” distribution of divalent ions, the latter performs better than the nonpolarizable force field. In particular, by imposing the experimental unit cell environment, an initial configuration with ideal B‐DNA duplexes in the unit cell acquires sequence‐dependent features that very closely resemble the crystallographic ones. Simultaneously, the all‐atom root‐mean‐square coordinates deviation (RMSD) with respect to the crystallographic structure is seen to decay. At later times, the polarizable force field is able to maintain this lower RMSD, while the nonpolarizable force field starts to drift away. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Die Gustav‐Heinemann‐Brücke über die Spree im neuen Zentrum Berlins – Moderne Lösungen der schwingungstechnischen Probleme eines schlanken Überbaus
Authors: Zimmer Eva‐Marie , Mündecke Michael 
Published: August 2006

AbstractIm neuen Zentrum Berlins, dem Spreebogen zwischen Regierungs‐ und Parlamentsbereich und dem neuen Bahnkreuzungspunkt Berlin Hauptbahnhof, wurde als kurze Verbindung die Gustav‐Heinemann‐Fußgängerbrücke über die Spree errichtet. Der im Ergebnis eines Gutachterverfahrens ausgewählte Entwurf eines sehr schlanken Vierendeelträgers war von vornherein als schwingungsanfällig, sowohl für fußgängerinduzierte als möglicherweise auch für windinduzierte Schwingungen anzusehen.Es wird nach der Beschreibung des Bauwerks und der städtebaulichen Situation über die Berechnungen zur Ermittlung des Schwingungsverhaltens bei Anregung durch Fußgänger bzw. zur Abschätzung des Schwingungsverhaltens bei Anregung durch Wind und über die Berechnungen zur Konfektionierung von Schwingungstilgern/‐dämpfern berichtet. Abschließend werden die notwendigen Versuche zur Absicherung der Rechenergebnisse und zum Nachweis der Wirksamkeit der Tilger vorgestellt.
Erdbebenbemessung von Stahlbauten nach neuer DIN 4149‐1
Authors: Akkermann Jan , Constantinescu Dan 
Published: August 2006

AbstractDie neue deutsche, seit April 2005 im Weißdruck vorliegende Erdbeben‐Bemessungsnorm gibt gegenüber ihrer Vorgängerin auch für Stahlbauten eine Vielzahl neuer Bemessungs‐ und Konstruktionsregeln vor. Im vorliegenden Beitrag werden die wesentlichen Bemessungsmethoden und die Besonderheiten für den Stahlbau vor dem Hintergrund der Praxisanwendung vorgestellt.
GABAA receptor regulation of voluntary ethanol drinking requires PKCϵ
Authors: Besheer Joyce , Lepoutre Veronique , Mole Beth , Hodge Clyde W. 
Published: August 2006

AbstractProtein kinase C (PKC) regulates a variety of neural functions, including ion channel activity, neurotransmitter release, receptor desensitization and differentiation. We have shown previously that mice lacking the ε‐isoform of PKC (PKCε) self‐administer 75% less ethanol and exhibit supersensitivity to acute ethanol and allosteric positive modulators of GABAA receptors when compared with wild‐type controls. The purpose of the present study was to examine involvement of PKCε in GABAA receptor regulation of voluntary ethanol drinking. To address this question, PKCε null‐mutant and wild‐type control mice were allowed to drink ethanol (10% v/v) vs. water on a two‐bottle continuous access protocol. The effects of diazepam (nonselective GABAA BZ positive modulator), zolpidem (GABAA α1 agonist), L‐655,708 (BZ‐sensitive GABAA α5 inverse agonist), and flumazenil (BZ antagonist) were then tested on ethanol drinking. Ethanol intake (grams/kg/day) by wild‐type mice decreased significantly after diazepam or zolpidem but increased after L‐655,708 administration. Flumazenil antagonized diazepam‐induced reductions in ethanol drinking in wild‐type mice. However, ethanol intake by PKCε null mice was not altered by any of the GABAergic compounds even though effects were seen on water drinking in these mice. Increased acute sensitivity to ethanol and diazepam, which was previously reported, was confirmed in PKCε null mice. Thus, results of the present study show that PKCε null mice do not respond to doses of GABAA BZ receptor ligands that regulate ethanol drinking by wild‐type control mice. This suggests that PKCε may be required for GABAA receptor regulation of chronic ethanol drinking. Synapse 60:411–419, 2006. © 2006 Wiley‐Liss, Inc.
Macroscopic properties of spontaneous mutations in slow‐channel syndrome: Correlation by domain and disease severity
Authors: Zayas Roberto , Lasalde‐Dominicci Jose , Gomez Christopher M. 
Published: August 2006

AbstractThe slow‐channel syndrome (SCS) is a neuromuscular disorder characterized by fatigability, progressive weakness, and degeneration of the neuromuscular junction. The SCS is caused by missense mutations in the four subunits of the skeletal muscle acetylcholine receptor (AChR), which leads to altered channel gating, prolonged neuromuscular postsynaptic currents, and impaired neuromuscular transmission. Although a diverse set of mutations in different functional domains of the AChR appear to be associated with symptoms of widely ranging severity, there is as yet no mutant channel property or combination that explains the variations in disease severity. By observing the recovery time of AChR from desensitization, the authors determined that this process is significantly enhanced in SCS channels. In addition, as expected, the authors found that SCS macroscopic decay currents in transfected HEK293 cells are slower than wild type currents. While slight differences in relative Ca2+ permeability between some SCS mutations were identified, they did not correlate with apparent disease severity. These results suggest that of the different AChR kinetic features studied, only recovery from desensitization and slow postsynaptic currents correlate with the severity observed in the different mutations of this syndrome. Synapse 60:441–449, 2006. © 2006 Wiley‐Liss, Inc.
Dielectric properties of graphite nanocomposites
Authors: Wong Shing‐Chung , Wouterson Erwin M. , Sutherland Eric M. 
Published: August 2006

AbstractPolymer nanocomposites are an emerging class of multifunctional materials that have not been optimized for their functional potential. In this study, the dielectric properties of graphite polymer nanocomposites were evaluated. The objective was to develop for composite applications, an alternative cost‐effective nanoscale carbon material with properties comparable to those of carbon nanotubes. J. VINYL. ADDIT. TECHNOL., 12:127–130, 2006. © 2006 Society of Plastics Engineers
Effect of high molecular weight acrylic copolymers on the viscoelastic properties of engineering resins
Authors: Mekhilef Nafaa , Hong Sheng , Carrington Courtney , Davis Benjamin 
Published: August 2006

AbstractIn this work, the viscoelastic properties of acrylic‐based copolymer blends with poly(methyl methacrylate) (PMMA) and polycarbonate were investigated in the molten and solid states. High molecular weight copolymers of methyl methacrylate with butyl acrylate (MMA‐co‐BA) having varying molecular weight and composition were used to enhance the rheological properties in shear and extension. Blends containing up to 15 wt% of copolymer were prepared at 200°C and 150 rpm by using a DSM micro‐compounder. The samples were characterized by size exclusion chromatography (SEC), dynamic mechanical analysis (DMA), and rheology. The rheological properties were determined by using small amplitude oscillatory measurements (SAOM) in shear and a Rheotens™ device for melt strength determination. For PMMA, the effects of high molecular weight PMMA copolymer on the matrix were related to the molecular weight, the tacticity of the copolymer, and the individual components. The rheological properties in shear showed enhanced storage and loss moduli at low frequency, while no change was observed at high frequency. In addition, extensional viscosity measurements made by using the filament stretching technique showed a significant increase in melt strength compared to that of the base PMMA with the blend containing the highest molecular weight copolymer showing the maximum force and a reduced drawdown ratio. For polycarbonate, its blends with acrylic copolymer were found to be immiscible. Similar enhancement in the moduli at low frequencies was observed, but a significant increase in the viscosity was obtained as well, resulting from the response of the two‐phase system. This change in the rheological properties was further increased at 15 wt% loading. Owing to the formation of a phase‐separated morphology, the melt strength was found to increase only slightly. J. VINYL. ADDIT. TECHNOL., 12:143–150, 2006. © 2006 Society of Plastics Engineers
Systolic and diastolic heart failure: Different phenotypes of the same disease?
Authors: De Keulenaer Gilles W. , Brutsaert Dirk L. 
Published: August 2006

AbstractTraditional pathophysiological concepts of chronic heart failure have largely focused on the haemodynamic consequences of ventricular systolic dysfunction. How these concepts relate to the pathophysiology of diastolic heart failure, i.e., heart failure with a preserved ejection fraction is, however, unclear, causing uncertainty about pathophysiology, diagnosis and management.Recent measurements of regional myocardial systolic function in patients with diastolic heart failure indicate that systolic and diastolic heart failure may be more closely related than previously anticipated. Rather than being considered as separate diseases with a distinct pathophysiology, systolic and diastolic heart failure may be merely different clinical presentations within a phenotypic spectrum of one and the same disease. In this review, we will interpret these new insights in a broader conceptual context of chronic heart failure and design novel paradigms in which systolic and diastolic heart failure jointly progress in a pathophysiological time trajectory of only one disease.
Thyroid pathology and the globus symptom: are they related? A two year prospective trial
Authors: Burns P , Timon C 
Published: August 2006

Introduction: The globus sensation is a constant feeling of a lump in the throat and may be associated with thyroid enlargement. A two year prospective study was set up to ascertain the relationship between thyroid pathology and globus symptoms.Materials and methods: All patients undergoing thyroid surgery over a two year period were included. Patients were questioned pre- and post-operatively. Globus symptom scores were recorded using a visual analogue scale. The size, weight and histological features of the removed specimens were correlated and statistical analysis performed.Results: Two hundred patients were included in the study; 58 were symptomatic for globus pharyngeus pre-operatively, and 80 per cent of these patients' symptoms resolved post-operatively (p≤0.0001). Patients with histological features of inflammation showed the greatest improvement (p≤0.0001).Conclusion: As many as one-third of patients with a thyroid mass will complain of a globus-like symptom. Patients undergoing thyroid surgery, who are symptomatic for globus pharyngeus, can expect that their symptoms will improve following surgery.
Partial correlation coefficient between distance matrices as a new indicator of protein–protein interactions
Authors: Sato Tetsuya , Yamanishi Yoshihiro , Horimoto Katsuhisa , Kanehisa Minoru , Toh Hiroyuki 
Published: August 2006

Abstract
Motivation: The computational prediction of protein–protein interactions is currently a major issue in bioinformatics. Recently, a variety of co-evolution-based methods have been investigated toward this goal. In this study, we introduced a partial correlation coefficient as a new measure for the degree of co-evolution between proteins, and proposed its use to predict protein–protein interactions.
Results: The accuracy of the prediction by the proposed method was compared with those of the original mirror tree method and the projection method previously developed by our group. We found that the partial correlation coefficient effectively reduces the number of false positives, as compared with other methods, although the number of false negatives increased in the prediction by the partial correlation coefficient.
Availability: The R script for the prediction of protein–protein interactions reported in this manuscript is available at
Contact: sato@kuicr.kyoto-u.ac.jp
Supplementary information: The information is also available at the same site as the R script.
Orbital Sequelae of Rhinosinusitis After Cochlear Implantation in Children
Authors: Rudnick Emily F. , Chu Michael W. , Sismanis Aristides , Dodson Kelley M. , Mitchell Ron B. 
Published: August 2006

AbstractObjectives: The objectives of this retrospective case review were to describe orbital complications in children after cochlear implantation, to define rhinosinusitis as a possible preoperative risk factor, and to suggest a possible pathophysiological mechanism for this previously unreported occurrence.Methods. Records of children undergoing cochlear implantation over a 7‐year period at a tertiary academic medical center were reviewed. Four children who experienced postoperative orbital sequelae were identified. We describe the demographics, clinical course, and radiologic findings in these children.Results: The records of 91 children who underwent cochlear implantation were reviewed. The mean age was 6.0 years (range, 0.9–16.9 years). Forty‐nine children (54%) were female and 51 (56%) were white. Four children developed postoperative orbital complications on the ipsilateral side to implantation. Orbital complications were characterized by periorbital edema and preseptal cellulitis necessitating prolonged hospitalization in all four children (mean length of stay, 3.3 days). Each child's orbital complication resolved with medical therapy that included intravenous antibiotics and nasal saline. Temporal bone images before implantation showed evidence of rhinosinusitis in all four cases. Of 76 available preoperative scans from the unaffected children, only 11 (14%) studies showed evidence of rhinosinusitis.Conclusions: Children with preoperative radiologic evidence of rhinosinusitis may be at risk of orbital sequelae after cochlear implantation. Positioning of the patient during surgery, length of surgery, and minor trauma to the lamina papyracea during drilling of the mastoid may be important etiologic factors. A careful review of medical history and computed tomography imaging before implantation may identify at‐risk children.
Water May Cure Patients With Meniere Disease
Authors: Naganuma Hideaki , Kawahara Katsumasa , Tokumasu Koji , Okamoto Makito 
Published: August 2006

AbstractObjectives/Hypothesis: We examined whether sufficient water intake is effective in the long‐term control of vertigo and hearing activity in patients with Meniere disease (MD) for whom conventional therapy has proven unsuccessful.Study Design: The authors conducted a time‐series study with historical control.Methods: Eighteen patients with MD in group 1 drank 35 mL/kg per day of water for 2 years. Twenty‐nine patients with MD treated with the conventional dietary and diuretic therapy for more than 2 years during 1992 to 1999 at the same hospital were enrolled in a historical control of group 2.Results: Patients in group 1 dramatically relieved vertigo and significantly improved in the hearing of the worst pure‐tone average of three frequencies (0.125, 0.25, and 0.5 kHz) (low PTA) during the last 6 months of the study period. In contrast, patients in group 2 became worse in both the four‐ (0.5, 1, 2, and 4 kHz) frequency PTA and the low PTA, although their vertigo did improve. The number of patients whose hearing were improved, unchanged, and worse were 4, 12, and 2 in group 1 and 2, 11, and 16 in group 2, respectively.Conclusion: Deliberate modulation of the intake of water may be the simplest and most cost‐effective medical treatment for patients with MD. Larger studies will be needed to confirm these results in a larger patient cohort.
Mcm‐2 and Ki‐67 Have Limited Potential in Preoperative Diagnosis of Thyroid Malignancy
Authors: Mehrotra Pallavi , Gonzalez Michael A. , Johnson Sarah J. , Coleman Nick , Wilson Janet A. , Davies Barry R. , Lennard Tom W. J. 
Published: August 2006

AbstractObjectives: Minichromosome maintenance protein 2 (Mcm‐2) is essential for DNA replication and serves as a useful biomarker of cell‐cycle state in human tissue samples. Ki‐67 is an established proliferation marker. Because Mcm‐2 expression has not previously been assessed in thyroid tissue, the aim of this study was to assess the expression of both proteins in a range of thyroid lesions to determine their potential value as preoperative markers of thyroid malignancy.Methods: Mcm‐2 and Ki‐67 protein expression were assessed by immunohistochemistry in formalin‐fixed, paraffin‐embedded thyroid tissues from 128 patients with histologic diagnoses of papillary carcinoma (n = 38), follicular carcinoma (n = 22), follicular adenoma (n = 33), and dominant nodules of multinodular goitre (n = 35).Results: Mcm‐2 and Ki‐67‐labeling indices (LIs) were both higher in follicular and papillary carcinomas than in follicular adenomas or dominant nodules. The Ki‐67 LI discriminated better between follicular carcinomas and follicular adenomas (P < .0001) than Mcm‐2 (P = .0273). However, the Mcm‐2 and Ki‐67 LIs overlapped widely between the four histologic groups, and the expression of these proteins was also noted to be heterogenous within these lesions.Conclusion: Neither Mcm‐2 or Ki‐67 can currently be reliably applied as preoperative markers to distinguish benign from malignant thyroid lesions.
Multichannel Cochlear Implants: Relation of Histopathology to Performance
Authors: Fayad Jose N. , Linthicum Fred H. 
Published: August 2006

AbstractObjectives: To determine the relationship of surviving neural elements to auditory function in multichannel cochlear implant temporal bones.Study Design: Case series of all 14 existing multichannel cochlear implants in our temporal bone collection.Methods: Devices included Nucleus 22 (n = 11), Nucleus 24 (n = 1), Ineraid (n = 1), and Clarion (n = 1). Morphologic evaluation of structural elements including spiral ligament, stria vascularis, hair cells, peripheral processes, and spiral ganglion cells was performed. Clinical performance data were obtained from patient charts. For eight patients, nonimplanted contralateral temporal bones were available and paired comparisons were made.Results: Despite frequent absence of hair cells and peripheral processes, all bones had at least some remaining spiral ganglion cells. Percent of normal remaining structures were unrelated to auditory performance with the implant for any of the structural elements. Ganglion cell count in segment III showed significant negative correlations to speech discrimination scores for words and sentences (Rhos = −.687 and −.661, P ≤ .03 and .04) as did segment IV and total ganglion cell count with word score (Rhos = −.632 and −.638; P ≤ .05). Spiral ganglion cell survival did not differ between implanted and nonimplanted ears, with the exception of segment I, which had fewer cells in the implanted ear (P ≤ .028).Conclusions: Performance variability of cochlear implants cannot be explained on the basis of cochlear neuronal survival. Although hair cells and peripheral processes were frequently absent or greatly diminished from normal, all subjects had at least some spiral ganglion cells. And, in this series, there was an inverse relationship between survival of ganglion cells and performance.
Complications of Surgery for Nasal Polyposis and Chronic Rhinosinusitis: The Results of a National Audit in England and Wales
Authors: Hopkins Claire , Browne John P. , Slack Rob , Lund Valerie J. , Topham John , Reeves Barnaby C. , Copley Lynn P. , Brown Peter , van der Meulen Jan H.P. 
Published: August 2006

AbstractObjective: The objective of this study was to determine the rate of complications of surgery for nasal polyposis and chronic rhinosinusitis as well as their risk factors.Study Design, Setting, Participants, and Outcome Measures: The authors conducted a prospective study of 3,128 patients who underwent sinonasal surgery during 2000 and 2001 in 87 National Health Service hospitals in England and Wales. Patients completed a preoperative questionnaire that included the Sino‐Nasal Outcome Test, a measure of sinonasal symptoms severity and health‐related quality of life. Surgeons provided information about polyp extent, opacity of the sinuses on computed tomography (Lund‐Mackay score), comorbidity (American Society of Anesthesiologists score), and the occurrence of perioperative complications.Results: Major complications (orbital or intracranial complications, bleeding requiring ligation or orbital decompression, or return to the operating room) occurred in 11 patients (0.4%). Minor complications (all other untoward events) occurred in 207 patients (6.6%). Most frequently reported minor complications were excessive perioperative hemorrhage bleeding (5.0%) as well as postoperative hemorrhage requiring treatment (0.8%). Multivariate analysis indicated that the complication rate was linked to the extent of disease measured in terms of symptom severity and health‐related quality of life, the extent of polyposis, level of opacity of the sinuses on computed tomography, and the presence of comorbidity, but not surgical characteristics (extent of surgery, use of endoscope or microdebrider, grade of surgeon, and adjunctive turbinate surgery).Conclusions: The risk of complications depended on patient characteristics rather than on the surgical technique used. Measures of the extent of disease and comorbidity may help in identifying patients at high risk of complications.