bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gallbladder cancer worldwide: Geographical distribution and risk factors
Authors: Randi Giorgia , Franceschi Silvia , La Vecchia Carlo 
Published: January 2006

AbstractGallbladder cancer is a relatively rare neoplasm that shows, however, high incidence rates in certain world populations. The interplay of genetic susceptibility, lifestyle factors and infections in gallbladder carcinogenesis is still poorly understood. Age‐adjusted rates were calculated by cancer registry‐based data. Epidemiological studies on gallbladder cancer were selected through searches of literature, and relative risks were abstracted for major risk factors. The highest gallbladder cancer incidence rates worldwide were reported for women in Delhi, India (21.5/100,000), South Karachi, Pakistan (13.8/100,000) and Quito, Ecuador (12.9/100,000). High incidence was found in Korea and Japan and some central and eastern European countries. Female‐to‐male incidence ratios were generally around 3, but ranged from 1 in Far East Asia to over 5 in Spain and Colombia. History of gallstones was the strongest risk factor for gallbladder cancer, with a pooled relative risk (RR) of 4.9 [95% confidence interval (CI): 3.3–7.4]. Consistent associations were also present with obesity, multiparity and chronic infections like Salmonella typhi and S. paratyphi [pooled RR 4.8 (95% CI: 1.4–17.3)] and Helicobacter bilis and H. pylori [pooled RR 4.3 (95% CI: 2.1–8.8)]. Differences in incidence ratios point to variations in gallbladder cancer aetiology in different populations. Diagnosis of gallstones and removal of gallbladder currently represent the keystone to gallbladder cancer prevention, but interventions able to prevent obesity, cholecystitis and gallstone formation should be assessed. © 2006 Wiley‐Liss, Inc.
A solid‐state NMR investigation of the structure of nanocrystalline hydroxyapatite
Authors: Jäger Christian , Welzel Thea , Meyer‐Zaika Wolfgang , Epple Matthias 
Published: January 2006

AbstractNanocrystalline hydroxyapatite (HAp) prepared by a precipitation route was investigated. The X‐ray diffraction (XRD) powder patterns of the elongated nanocrystals with a typical diameter of about 10 nm and length of 30–50 nm (by transmission electron microscopy (TEM)) revealed the presence of HAp with significantly broadened XRD reflections. However, Ca deficiency was found, as the Ca/P ratio was 1.5 only (so‐called calcium‐deficient hydroxyapatite (CDHA)), and not 1.67. This Ca deficiency of nanocrystalline HAp is explained using NMR. It is shown unambiguously that (i) the nanocrystals consist of a crystalline core and a (disordered) surface region with a relative phosphate content of about 1:1, (ii) the crystalline core is HAp, and (iii) the surface region is dominated by hydrogen phosphate anions (with no hydroxyapatite‐like structural motif) and structural water (hydrate). From the relative phosphate content and taking into account the crystal shape, the thickness of the surface layer along the main crystal axis could be estimated to be about 1 nm, and the average chemical composition of the surface layer has been determined. Finally, a Ca/P ratio of 1.52 was estimated from the NMR data that compares well with the value of 1.51 from chemical analysis. The important consequences are that the surface of nanocrystalline HAp has nothing in common with the bulk composition and that the chemistry of such materials (e.g. the binding of protein molecules to phosphate surfaces) must be reconsidered. Copyright © 2006 John Wiley & Sons, Ltd.
Effect of hydrophilicity on the properties of a degradable polylactide
Authors: Boxberg Yvonne , Schnabelrauch Matthias , Vogt Sebastian , Sánchez Manuel Salmerón , Ferrer Gloria Gallego , Pradas Manuel Monleón , Antón Julio Suay 
Published: January 2006

AbstractA series of polylactide networks has been prepared by the copolymerization of a biodegradable oligolactide macromer with hydrophobic methyl methacrylate monomer and hydrophilic hydroxyethyl acrylate monomer, with different amounts of the hydrophilic monomer. The incorporation of the hydrophilic units into the network has been characterized with thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical spectrometry. A homogeneous material results, showing a single glass‐transition temperature and a characteristic relaxation behavior that is not the sum of those of the pure components separately. Additional hydrophilic units in the network chains lower the rubbery modulus, keeping a high modulus value at room temperature, and manifestly increase the degradation rate of the polymer. This can be attributed both to the higher water swellability of the network when hydrophilic units are present and to the higher water diffusion coefficient in a network, which has a lower crosslinking density. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 656–664, 2006
A correlation‐based method for the enhancement of scoring functions on funnel‐shaped energy landscapes
Authors: Stumpff‐Kane Andrew W. , Feig Michael 
Published: January 2006

AbstractA correlation‐based approach is introduced for enhancing the ability of structure‐scoring methods to identify and distinguish native‐like conformations. The proposed method relies on a funnel‐shaped scoring function that decreases steadily toward the native state. It takes advantage of the idea that the structure from a given ensemble that is closest to the native basin leads to the highest correlation coefficient between a given score and distance to that structure as an approximation of the native state for the entire ensemble. The method is applied successfully to a number of different test cases that demonstrate substantial improvements in the correlation of the score with the distance from the true native state but also result in the selection of more native‐like structures compared to the original score. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Fabrication and magnetoelectronic properties of field aligned CrO2 powders
Authors: Tripathy D. , Adeyeye A. O. 
Published: January 2006

AbstractWe have combined field alignment technique together with lithography to fabricate CrO2 powder based devices. A systematic study of the temperature‐dependent magnetoelectronic properties has been carried out. The devices exhibit strong anisotropy along the alignment direction at all temperatures. Temperature dependent analysis of the hysteresis loops shows that coercivity of the field aligned powders increases with decreasing temperature. The conduction mechanism has been examined in detail and a transition from tunneling across grain boundaries to inelastic hopping was observed at 215 K. This transition temperature shifts to 230 K in the presence of 10 kOe field cooling due to reduction of the spin‐independent hopping conductance channel. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atmospheric pressure ionisation mass spectrometric fragmentation pathways of noscapine and papaverine revealed by multistage mass spectrometry and in‐source deuterium labelling
Authors: Wickens James R. , Sleeman Richard , Keely Brendan J. 
Published: January 2006

AbstractTwo opium alkaloids, noscapine and papaverine, show good response as [M+H]+ ions in positive ion electrospray mass spectrometry and atmospheric pressure chemical ionisation mass spectrometry. The two compounds exhibit markedly different fragmentation pathways and behaviour under multistage mass spectrometry (MSn), with papaverine displaying a wealth of ions in MS2 and noscapine providing a single dominant ion at each stage of MSn prior to MS4. Elucidation of the fragmentation pathways using the MSn capability of the ion trap was aided by spraying the analytes in 2H2O to incorporate an isotopic label. Simplex optimisation allowed optimum trapping and fragmentation parameters to be determined, leading to a six‐fold improvement in response for one transition and a seven‐fold improvement for one transition sequence. Copyright © 2006 John Wiley & Sons, Ltd.
On estimation of the variance in Cochran–Armitage trend tests for genetic association using case–control studies
Authors: Zheng Gang , Gastwirth Joseph L. 
Published: January 2006

AbstractThe Cochran–Armitage trend test has been used in case–control studies for testing genetic association. As the variance of the test statistic is a function of unknown parameters, e.g. disease prevalence and allele frequency, it must be estimated. The usual estimator combining data for cases and controls assumes they follow the same distribution under the null hypothesis. Under the alternative hypothesis, however, the cases and controls follow different distributions. Thus, the power of the trend tests may be affected by the variance estimator used. In particular, the usual method combining both cases and controls is not an asymptotically unbiased estimator of the null variance when the alternative is true. Two different estimates of the null variance are available which are consistent under both the null and alternative hypotheses. In this paper, we examine sample size and small sample power performance of trend tests, which are optimal for three common genetic models as well as a robust trend test based on the three estimates of the variance and provide guidelines for choosing an appropriate test. Copyright © 2006 John Wiley & Sons, Ltd.
Minimization of the energy storage requirements of a stand‐alone wind power installation by means of photovoltaic panels
Authors: Kaldellis J.K. , Kostas P. , Filios A. 
Published: January 2006

AbstractAutonomous wind power systems are among the most interesting and environmentally friendly technological solutions for the electrification of remote consumers. In many cases, however, the battery contribution to the initial or the total operational cost is found to be dominant, discouraging further penetration of the available wind resource. This is basically the case for areas possessing a medium–low wind potential. On the other hand, several isolated consumers are located in regions having the regular benefit of an abundant and reliable solar energy supply. In this context the present study investigates the possibility of reducing the battery size of a stand‐alone wind power installation by incorporating a small photovoltaic generator. For this purpose an integrated energy production installation based exclusively on renewable energy resources is hereby proposed. Subsequently a new numerical algorithm is developed that is able to estimate the appropriate dimensions of a similar system. According to the results obtained by long‐term experimental measurements, the introduction of the photovoltaic panels considerably improves the operational and financial behaviour of the complete installation owing to the imposed significant battery capacity diminution. Copyright © 2006 John Wiley & Sons, Ltd.
Quantifying offshore wind resources from satellite wind maps: study area the North Sea
Authors: Hasager C. B. , Barthelmie R. J. , Christiansen M. B. , Nielsen M. , Pryor S. C. 
Published: January 2006

AbstractOffshore wind resources are quantified from satellite synthetic aperture radar (SAR) and satellite scatterometer observations at local and regional scale respectively at the Horns Rev site in Denmark. The method for wind resource estimation from satellite observations interfaces with the wind atlas analysis and application program (WAsP). An estimate of the wind resource at the new project site at Horns Rev is given based on satellite SAR observations. The comparison of offshore satellite scatterometer winds, global model data and in situ data shows good agreement. Furthermore, the wake effect of the Horns Rev wind farm is quantified from satellite SAR images and compared with state‐of‐the‐art wake model results with good agreement. It is a unique method using satellite observations to quantify the spatial extent of the wake behind large offshore wind farms. Copyright © 2006 John Wiley & Sons, Ltd.
The heritability of perceived stress
Authors: FEDERENKO ILONA S. , SCHLOTZ WOLFF , KIRSCHBAUM CLEMENS , BARTELS MEIKE , HELLHAMMER DIRK H. , WÜST STEFAN 
Published: January 2006

Background. Exploration of the degree to which perceived chronic stress is heritable is important as these self-reports have been linked to stress-related health outcomes. The aims of this study were to estimate whether perceived stress is a heritable condition and to assess whether heritability estimates vary between subjective stress reactivity and stress related to external demands.Method. A sample of 103 monozygotic and 77 dizygotic twin pairs completed three questionnaires designed to measure perceived stress: the Perceived Stress Scale (PSS), the Measure for the Assessment of Stress Susceptibility (MESA) and the Trier Inventory for the Assessment of Chronic Stress (TICS). The TICS assesses the frequency of stressful experiences on six scales, the MESA assesses subjective stress reactivity, and the PSS takes both factors into account.Results. A multivariate model-fitting procedure revealed that a model with common additive genetic and shared environmental factors best fit the eight scales (PSS, MESA, six TICS scales). Heritabilities for the best-fitting model varied between 5% and 45%, depending on the scale.Conclusions. The present data suggest that perceived stress is in part heritable, that nearly half of the covariance between stress scales is due to genetic factors, and that heritability estimates vary considerably, depending on the questionnaire. Beyond methodological considerations that pertain to the validity of the questionnaires, these data suggest that studies assessing the heritability of perceived chronic stress should take the specific questionnaire focus into account.
Local Recurrence after CO2 Laser Cordectomy for Early Glottic Carcinoma
Authors: Mortuaire G , Francois J , Wiel E , Chevalier D 
Published: January 2006

AbstractObjectives: To point out prognosis factors of local recurrence after endoscopic cordectomies for Tis, T1a, T1b, and T2 glottic squamous cell carcinomas.Study Design: A cohort of 110 patients treated from January 1990 to December 2000 at a single institution was retrospectively analyzed: 21 had Tis, 76 T1a, 7 T1b, and 6 T2 (mean follow‐up 42 mo; range 1–160 mo).Methods: The depth and extension of the excision were graded according to the European Laryngological Society Classification. Univariate analysis was used to review the impact on disease‐free survival of factors related to the host, the tumor, and the treatment.Results: According to the Kaplan‐Meier method, the 5 year overall survival and the disease‐free survival were 87% and 75%, respectively. The rates of cause‐specific survival, ultimate local control with laser alone, and laryngeal preservation were 97%, 84%, and 90%, respectively. Univariate analysis by the log rank test revealed that vocal muscle infiltration (P = .001) and subglottic involvement (P = .02) have a significant impact on disease‐free survival. Of the 22 patients with local recurrence (17 T1a, 1 T1b, and 4 T2), 9 were managed with total laryngectomy, 5 with partial laryngectomy, 4 with further laser cordectomy, 2 with radiotherapy, and 2 had no curative treatment.Conclusion: Transoral laser surgery for early glottic carcinoma is a valid alternative to radiotherapy and partial laryngectomy in terms of oncologic results. It offers low morbidity and excellent retreatment options in case of local failure. Careful patient selection for laser surgery is essential to secure good results.
Cricopharyngeal Myotomy Normalizes the Opening Size of the Upper Esophageal Sphincter in Cricopharyngeal Dysfunction
Authors: Yip Helena T. , Leonard Rebecca , Kendall Katherine A. 
Published: January 2006

AbstractObjective: The development of a cricopharyngeal dysfunction is associated with a hypertonic cricopharyngeus (CP) muscle. Therefore, CP myotomy has been advocated by some authors to be an essential part of repair of this condition. However, little objective data exists to show that there is improvement in the upper esophageal sphincter (UES) after CP myotomy. This study assesses the impact of CP myotomy on UES opening.Study Design: Prospective.Methods: Twenty patients treated at a university tertiary care center for cricopharyngeal dysfunction between 1998 and 2003 were identified. All patients underwent CP myotomy with or without Zenker's diverticulectomy. These patients had videofluoroscopic swallow studies before and after repair. The values of UES opening for 3 mL boluses from pre‐ and postrepair studies were compared with each other as well as with normal controls. Sixty percent (12/20) of the patients had a Zenker's diverticulum. Of these 12 patients, 5 had undergone previous attempts at surgical correction. Cricopharyngeal myotomy by way of an external approach, with or without Zenker's diverticulectomy, was performed in all patients by the senior author.Results: Before Zenker's diverticulectomy and CP myotomy, the mean UES opening (n = 20) for a 3 mL bolus was 0.30 cm ± 0.17, which was 57% of the mean of 60 normal controls (0.52 cm ± 0.15) (P < .001). After repair, the mean UES opening for the same bolus size improved to 0.51 cm ± 0.16 (P < .0001). The UES opening size in patients who have undergone repair is comparable with that of the normal controls (P > .05).Conclusions: UES opening size in patients with cricopharyngeal dysfunction is 57% of the size in normal controls. CP myotomy helps to normalize the UES opening in cricopharyngeal dysfunction repair.
Objective Sizing of Upper Airway Stenosis: A Quantitative Endoscopic Approach
Authors: Nouraei S. A. R. , McPartlin D. W. , Nouraei S. M. , Patel A , Ferguson C , Howard D. J. , Sandhu G. S. 
Published: January 2006

AbstractObjective: In patients with airway stenosis, anatomy of the lesion determines the magnitude of the biomechanical ventilatory disturbance and thus the nature and severity of symptoms. It also gives information about biology, likelihood of response to treatment, and prognosis of laryngotracheal lesions. Accurate airway sizing throughout treatment is therefore central to managing this condition. We developed a method for objective assessment of airway lesions during endoscopy.Methods: We used airway simulations to investigate the effects of endoscope tilt and lens distortions on measurement accuracy, devising and validating clinical rules for quantitative airway endoscopy. A calibrator was designed to assess lesion length, location, and cross‐section during tracheoscopy.Results: It proved possible to calculate the length and location of the stenosis using simple mathematics. Cross‐section measurements were more than 95% accurate, independent of endoscope tilt and without making assumptions about endoscope optics and visuospatial distortion, for both pediatric and adult airway dimensions. The technique was used to characterize airway lesions in 10 adult patients with an average age of 48 years undergoing therapeutic laryngotracheoscopy. Lesions occurred on average 36 mm below the glottis (range, 21–54 mm) and were 9.3 mm long (5–17 mm). The average pretreatment airway cross‐section was 48.3 mm2, increasing to 141.1 mm2 after laser therapy. Two independent observers calculated airway cross‐sections, achieving an interobserver concordance of 0.98.Conclusions: This method can be used to objectively and precisely determine the anatomy of airway lesions, allowing accurate documentation of lesion characteristics and surgical results, serial monitoring throughout treatment, and comparison of outcomes between different centers.
Serum Heat Shock Protein 70 and its Correlation with Clinical Characteristics in Patients with Sudden Sensorineural Hearing Loss
Authors: Park Shi‐Nae , Yeo Sang W. , Park Kyung‐Ho 
Published: January 2006

AbstractObjectives: Previous studies have reported that in cochlear cells, heat shock protein (HSP)70 is expressed after ototoxic stimuli. We performed this study to investigate the possibility of HSP70 being found in circulation and to observe its possible clinical role in patients with sudden sensorineural hearing loss (SSNHL).Methods: A total of 67 patients with SSNHL and age‐sex matched normal controls were included in this study. Their serum HSP70 levels were measured with highly sensitive enzyme‐linked immunoadsorbent assay (ELISA) test and confirmed with Western blot immunoassay. Clinical variables including initial and final audiometric findings and accompanying symptoms were analyzed to find the possible clinical value of serum HSP70 level in the patients with SSNHL.Results: Serum HSP70 levels were significantly higher in the patients with SSNHL than those of normal controls by ELISA test (P < .01), and their presence were confirmed as strong bands in the Western blot assay. There was significant correlation between serum HSP70 levels and the recovery of HL in the patients with SSNHL (P < .0l).Conclusion: This is the first report showing elevated serum HSP70 levels in the patients with SSNHL compared with normal controls. We suggest that serum HSP70 levels might have a clinical role for predicting prognosis of HL in the patients with SSNHL.
Improving Vestibular Evoked Myogenic Potential Reliability by using a Blood Pressure Manometer
Authors: Vanspauwen Robby , Wuyts Floris L. , Van de Heyning Paul H. 
Published: January 2006

AbstractObjective/Hypothesis: To improve the reliability of vestibular evoked myogenic potentials (VEMP), we propose a feedback method making use of a readily available blood pressure manometer with inflatable cuff to control the sternocleidomastoid muscle (SCM) contraction.Study Design: Prospective study.Materials and Methods: The feedback method for SCM contraction consisted of subjects pushing with their jaw against the hand‐held inflated cuff to generate a specified cuff pressure. This pressure level was monitored by subject and investigator. First, we tested in a group of healthy subjects whether there was a learning or fatigue effect during four successive SCM contraction runs when making use of the feedback method. Then, we investigated the mean rectified voltage (MRV) values of the SCM. Next, we examined the hypothesis that the MRV values of the SCM contraction measured before and simultaneously with the VEMP test were equal when using this feedback method. Finally, we compared the VEMP amplitude variability in two circumstances: with and without the feedback method.Results: There was no learning or fatigue effect, and the MRV values measured before the VEMP were not significantly different from those measured during the VEMP test. The VEMP amplitude variability was significantly lower when applying the feedback method than when no feedback method was used.Conclusion: This feedback method improves significantly the VEMP amplitude reliability.