bluuebunny/crossref_metadata_2025_split huggingface dataset:
Torsional profile of 2,2,2‐trifluoroethanol: A theoretical analysis with basis set extrapolation
Authors: de Amorim Mauro B. 
Published: July 2008

AbstractThe conformational potential for rotation around the CCOH torsional angle of 2,2,2‐trifluoroethanol (TFE) has been investigated at second‐order Möller–Plesset (MP2) perturbation theory with two series of Dunning's correlation consistent basis sets, cc‐pVNZ and aug‐cc‐pVNZ, N = D, T, Q, and 5. Single‐point energy calculations with MP4(SDQ)/(aug‐)cc‐pVTZ and MP4(SDQT)/cc‐pVTZ were also performed. It was found that the geometries of stationary points on this conformational profile are dependent on the basis set size, particularly the torsional angle of the gauche‐isomer and the transition structure between the gauche‐ and anti‐isomers (from 61° and 142°, respectively, at cc‐pVDZ, to 65° and 149° at aug‐cc‐pVQZ), requiring at least a aug‐cc‐pVTZ basis set to be correctly optimized. Additionaly, an even lower barrier height (as low as 0.04 kcal/mol) than that previously calculated by Senent et al. for the conversion of anti‐TFE to its more stable (by about 1.95 kcal/mol) gauche‐conformer has been obtained, which reinforces the prediction that the main, if not the only, component of TFE in gas phase is its gauche‐isomer. The MP2 data were also used in different schemes of basis set extrapolation. Unfortunately, maybe because third‐order correlation energy contributions were not considered, these schemes have failed in providing suitable extrapolated energies. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Fractionation of free and conjugated steroids for the detection of boldenone metabolites in calf urine with ultra‐performance liquid chromatography/tandem mass spectrometry
Authors: Van Poucke Christof , Van Vossel Evy , Van Peteghem Carlos 
Published: July 2008

AbstractFor over a decade there has been an intensive debate on the possible natural origin of boldenone (androst‐1,4‐diene‐17β‐ol‐3‐one, 17β‐boldenone) in calf urine and several alternative markers to discriminate between endogenously formed boldenone and exogenously administered boldenone have been suggested. The currently approved method for proving illegal administration of β‐boldenone(ester) is the detection of β‐boldenone conjugates. In the presented method the sulphate, glucuronide and free fractions are separated from each other during cleanup on a SAX column to be able to determine the conjugated status of the boldenone metabolites. The sulphate and glucuronide fractions are submitted to hydrolysis and all three fractions are further cleaned up on a combination of C18/NH2 solid‐phase extraction (SPE) columns. Chromatographic separation of the boldenone metabolites was achieved with a Waters Acquity UPLC™ instrument using a Sapphire C18 (1.7 µm; 2 × 50 mm) column within 5 min. Detection of the analytes was achieved by electrospray ionisation tandem mass spectrometry. The decision limits of this method, validated according to Commission Decision 2002/657/EC, were 0.08 ng mL−1 for androsta‐1,4‐diene‐3,17‐dione, 0.13 ng mL−1 for androst‐4‐ene‐3,17‐dione, 0.11 ng mL−1 for 17α‐boldenone, 0.07 ng mL−1 for 17β‐boldenone, 0.24 ng mL−1 for 5β‐androst‐1‐en‐17β‐ol‐3‐one and 0.58 ng mL−1 for 6β‐hydroxy‐17β‐boldenone. Because of the fractionation approach used in this method there is no need for conjugated reference standards which often are not available. The disadvantage of needing three analytical runs to determine the conjugated status of each of the metabolites was overcome by using fast chromatography. Copyright © 2008 John Wiley & Sons, Ltd.
A mobile multimedia satellite system reusing existing satellites
Authors: Midthassel Rolv , Ernst Harald 
Published: July 2008

AbstractSince 2001, the European Space Agency has investigated a file‐based system for providing satellite radio to the automotive market. This system is significantly different from existing commercial counterparts, such as the American systems XM‐radio and Sirius. In terms of service it not only provides traditional radio services but is also capable of offering multimedia content and data transfer. In terms of infrastructure, it does not require launch of new satellites or deployment of terrestrial repeaters. As such it offers a highly efficient, low‐investment and low‐risk approach to offering satellite radio services to a consumer automotive market. Moreover, it departs from the traditional schedule‐based streaming radio concept to a concept in line with the concurrent developments within the media landscape, providing the user the full control of what entertainment to play and when to play it. This paper presents the system in more detail, outlines its performance and makes comparisons with other existing satellite radio systems. Copyright © 2008 John Wiley & Sons, Ltd.
ETSI technical standards for satellite digital radio
Authors: Krause Jens , Stadali Holger 
Published: July 2008

AbstractThe European Telecommunications Standards Institute (ETSI) is a non‐profit organization that creates technical standards for different areas of telecommunications. The ETSI activity satellite digital radio (SDR) addresses networks where satellite transmission is used for broadcasting directly to mobile receivers and is complemented by terrestrial transmitters. ETSI standards allow implementing parts of such systems in an interoperable way. A standardized radio interface enables a mass market for consumer reception devices and could become a regulatory requirement. ETSI, so far, has created standards for the physical layer of the radio interface. State‐of‐the‐art technology for multiplexing, interleaving, modulation and coding is applied. The system is broken down into parts that are covered by separate standards, which allows combining with other existing or future specifications. The standards cover the direct satellite transmission and the complementary terrestrial transmission, with both their particular impairments and conditions. A sophisticated time interleaving allows one to overcome signal blockage in a way that increases the ‘zapping time’ only slightly. The physical layer standards can be combined with existing standards for audio/video coding and encapsulation, in particular from MPEG and DVB. ETSI is planning to create further standards for the SDR system. First networks that apply the SDR technology are expected in 2008. Copyright © 2008 John Wiley & Sons, Ltd.
Local variability in PTC thermistor grain boundary structures
Authors: Leach C. , Seaton J. 
Published: July 2008

AbstractScanning electron microscopy‐based conductive mode (CM) microscopy, using the remote electron beam‐induced current configuration, was carried out on a positive temperature coefficient of resistance thermistor at temperatures below and above the Curie temperature, TC. Below TC, when the thermistor is in a low resistance state, no strong CM contrast was observed. Above TC the thermistor grain boundaries become highly resistive and significant CM contrast formed owing to three mechanisms: all of the areas that were studied showed resistive contrast, but in addition some grain boundaries showed additional contrast due to electron beam‐induced current, the origin of which was consistent with the presence of a back‐to‐back Schottky barrier structure at the grain boundary. Other grain boundaries exhibited additional contrast owing to β‐conductivity, which suggests a slightly different n‐i‐n grain boundary structure at these interfaces. These results suggest that electrically active grain boundaries with different structures coexist within the thermistor. SCANNING 30: 339–346, 2008. © 2008 Wiley Periodicals, Inc.
Maximum likelihood estimation of correction for dilution bias in simple linear regression using replicates from subjects with extreme first measurements
Authors: Berglund Lars , Garmo Hans , Lindbäck Johan , Svärdsudd Kurt , Zethelius Björn 
Published: July 2008

AbstractThe least‐squares estimator of the slope in a simple linear regression model is biased towards zero when the predictor is measured with random error. A corrected slope may be estimated by adding data from a reliability study, which comprises a subset of subjects from the main study. The precision of this corrected slope depends on the design of the reliability study and estimator choice.Previous work has assumed that the reliability study constitutes a random sample from the main study. A more efficient design is to use subjects with extreme values on their first measurement. Previously, we published a variance formula for the corrected slope, when the correction factor is the slope in the regression of the second measurement on the first. In this paper we show that both designs improve by maximum likelihood estimation (MLE). The precision gain is explained by the inclusion of data from all subjects for estimation of the predictor's variance and by the use of the second measurement for estimation of the covariance between response and predictor. The gain of MLE enhances with stronger true relationship between response and predictor and with lower precision in the predictor measurements. We present a real data example on the relationship between fasting insulin, a surrogate marker, and true insulin sensitivity measured by a gold‐standard euglycaemic insulin clamp, and simulations, where the behavior of profile‐likelihood‐based confidence intervals is examined. MLE was shown to be a robust estimator for non‐normal distributions and efficient for small sample situations. Copyright © 2008 John Wiley & Sons, Ltd.
Flexible regression models for estimating postmortem interval (PMI) in forensic medicine
Authors: Muñoz Barús José Ignacio , Febrero‐Bande Manuel , Cadarso‐Suárez Carmen 
Published: July 2008

AbstractCorrect determination of time of death is an important goal in forensic medicine. Numerous methods have been described for estimating postmortem interval (PMI), but most are imprecise, poorly reproducible and/or have not been validated with real data. In recent years, however, some progress in PMI estimation has been made, notably through the use of new biochemical methods for quantifying relevant indicator compounds in the vitreous humour. The best, but unverified, results have been obtained with [K+] and hypoxanthine [Hx], using simple linear regression (LR) models. The main aim of this paper is to offer more flexible alternatives to LR, such as generalized additive models (GAMs) and support vector machines (SVMs) in order to obtain improved PMI estimates. The present study, based on detailed analysis of [K+] and [Hx] in more than 200 vitreous humour samples from subjects with known PMI, compared classical LR methodology with GAM and SVM methodologies. Both proved better than LR for estimation of PMI. SVM showed somewhat greater precision than GAM, but GAM offers a readily interpretable graphical output, facilitating understanding of findings by legal professionals; there are thus arguments for using both types of models. R code for these methods is available from the authors, permitting accurate prediction of PMI from vitreous humour [K+], [Hx] and [U], with confidence intervals and graphical output provided. Copyright © 2008 John Wiley & Sons, Ltd.
Fitting stratified proportional odds models by amalgamating conditional likelihoods
Authors: Mukherjee Bhramar , Ahn Jaeil , Liu Ivy , Rathouz Paul J. , Sánchez Brisa N. 
Published: July 2008

AbstractClassical methods for fitting a varying intercept logistic regression model to stratified data are based on the conditional likelihood principle to eliminate the stratum‐specific nuisance parameters. When the outcome variable has multiple ordered categories, a natural choice for the outcome model is a stratified proportional odds or cumulative logit model. However, classical conditioning techniques do not apply to the generalK‐category cumulative logit model (K>2) with varying stratum‐specific intercepts as there is no reduction due to sufficiency; the nuisance parameters remain in the conditional likelihood. We propose a methodology to fit stratified proportional odds model by amalgamating conditional likelihoods obtained from all possible binary collapsings of the ordinal scale. The method allows for categorical and continuous covariates in a general regression framework. We provide a robust sandwich estimate of the variance of the proposed estimator. For binary exposures, we show equivalence of our approach to the estimators already proposed in the literature. The proposed recipe can be implemented very easily in standard software. We illustrate the methods via three real data examples related to biomedical research. Simulation results comparing the proposed method with a random effects model on the stratification parameters are also furnished. Copyright © 2008 John Wiley & Sons, Ltd.
A survey of the likelihood approach to bioequivalence trials
Authors: Choi Leena , Caffo Brian , Rohde Charles 
Published: July 2008

AbstractBioequivalence (BE) trials are abbreviated clinical trials whereby a generic drug or new formulation is evaluated to determine if it is ‘equivalent’ to a corresponding previously approved brand‐name drug or formulation. In this paper, we survey the process of testing BE and advocate the likelihood paradigm for representing the resulting data as evidence. We emphasize the unique conflicts between hypothesis testing and confidence intervals in this area—which we believe are indicative of the existence of the systemic defects in the frequentist approach—that the likelihood paradigm avoids. We suggest the direct use of profile likelihoods for evaluating BE. We discuss how the likelihood approach is useful to present the evidence for both average and population BE within a unified framework. We also examine the main properties of profile likelihoods and estimated likelihoods under simulation. This simulation study shows that profile likelihoods offer a viable alternative to the (unknown) true likelihood for a range of parameters commensurate with BE research. Copyright © 2008 John Wiley & Sons, Ltd.
Quantifying the usefulness of PD biomarkers in Phase 2 screening trials of oncology drugs
Authors: Holmgren Eric 
Published: July 2008

AbstractThis paper develops a framework for evaluating the usefulness of a PD biomarker as a primary endpoint in a Phase 2 screening trial of an oncology drug. We judge the contribution of the PD biomarker by assessing its impact on the efficiency of the drug development process. ‘Efficiency’ is defined as the probability that an active drug is found to be effective in Phase 3 divided by the sum of the expected number of events in Phase 3 and the pre‐Phase 2 drug development costs appropriately normalized. We show that 20 Phase 2 trials of different experimental treatments can provide a reasonable answer as to whether a PD biomarker makes a positive or negative contribution to the drug development process. Copyright © 2008 John Wiley & Sons, Ltd.
Rheinbrücke Wesel – Konstruktion und statische Berechnung
Authors: Anistoroaiei Christian , Eilzer Wolfgang , Jung Rolf , Romberg Martin , Sagner Erik , Walser Peter 
Published: July 2008

AbstractDie neue Rheinbrücke Wesel ist Teil des Gesamtkonzeptes der Verkehrsumgehung der beiden Städte Wesel und Büderich. Mit einer Gesamtlänge von rd. 773 m und einer Hauptöffnung von 335 m ist sie die zur Zeit größte im Bau befindliche Schrägseilbrücke in Deutschland. Der Aufsatz befasst sich mit der Konstruktion und statischen Berechnung des Brückenzuges.
Die MaChang‐Brücke in Südkorea – Schrägkabelbrücke mit Verbundüberbau für Straßenverkehr
Authors: Hopf Siegfried , Patsch Armin , Walser Peter 
Published: July 2008

AbstractDie 1700 m lange MaChang‐Brücke ist Teil der Schnellstraßenverbindung zwischen den Städten Masan und Changwon im Süden von Korea und führt in etwa 68 m Höhe über die Bucht von Masan. Diese Hochbrücke besteht aus 550 bzw. 410 m langen Vorlandbrücken und einer 740 m langen Hauptbrücke. Die Hauptbrücke, eine 400 m weit gespannte Schrägseilbrücke mit zwei Pylonen, stellt das dominierende Bauwerk dieser Verbindung dar. Sie überspannt den 350 m breiten Schifffahrtskanal, welcher für Durchfahrten von Schiffen mit bis zu 80000 dwt ausgelegt ist.
Effect of Hydroxypropylation on the Properties of White Yam (Dioscorea rotundata) Starch
Authors: Lawal Olayide S. , Ogundiran Olusegun O. , Adesogan Ezekiel K. , Ogunsanwo Babatunde M. , Sosanwo Olumide A. 
Published: July 2008

AbstractStarch isolated from white yam (Dioscorea rotundata) was subjected to hydroxypropylation under different conditions. Corresponding increases were observed between the molar substitution (MS) and the volume of propylene oxide added to the reaction mixture. After hydroxypropylation, a slight reduction in the intensity of the peak at 2θ = 19.6° was observed and the doublet peak at 23.8°, which was present in native starch, was no longer seen. Hydroxypropylation enhanced the free swelling capacity (FSC) and solubility. Setback and retrogradation of native starch declined after hydroxypropylation. Turbidity of native starch paste and syneresis were higher with storage time. The results also indicate that enzymatic digestibility improved as the MS increased, while the reverse was observed for starch paste turbidity, syneresis, setback and retrogradation. This study presents relevant information that could strategically position D. rotundata starch and its hydroxypropylated derivatives for industrial applications.
Structure and Viscoelastic Properties of Starches Separated from Different Legumes
Authors: Singh Narpinder , Nakaura Yoshiko , Inouchi Naoyoshi , Nishinari Katsuyoshi 
Published: July 2008

AbstractA comparison between the morphological, structural, thermal and viscoelastic properties of starches separated from pigeon pea, chickpea, field pea, kidney bean and blackgram was made. The shape of the starch granules in the different legumes varied from oval to elliptical or spherical. X‐ray diffraction of the legume starches indicated a typical C‐pattern (mixture of A‐ and B‐type). Granules of blackgram and pigeon pea starch had a higher degree of crystallinity than those of field pea and kidney bean starches. Apparent amylose content of field pea, kidney bean, chickpea, blackgram and pigeon pea starch was 37.9%, 36.0%, 34.4‐35.5%, 32.9‐35.6% and 31.8%, respectively. Distribution of isoamylase‐branched materials among the starches revealed that the proportions of long and short side chains of amylopectin ranged between 13.6‐18.5% and 41.7‐46.5%, respectively. Field pea and kidney bean starch had the highest apparent amylose content and the lowest amount of long side chains of amylopectin, respectively. Blackgram and pigeon pea starch possessed higher proportions of both long and short side chains of amylopectin than field pea and chickpea starches. The onset, peak and conclusion temperatures of gelatinization (To Tp and Tc, respectively) were determined by differential scanning calorimetry. To and Tc ranged from 59.3 to 77.3°C, 66.8 to 79.6°C, 55.4 to 67.6°C and 68.3 to 69.3°C, respectively, for chickpea, blackgram, field pea and kidney bean starch. The enthalpy of gelatinization (ΔHgel) of field pea, kidney bean, chickpea, blackgram and pigeon pea starches was 3.6, 3.0, 2.6‐4.2, 1.6‐1.7 and 2.6 J/g, respectively. Pastes of blackgram and pigeon pea starches showed lower storage and loss shear moduli G′ than field pea, kidney bean and chickpea starches. The changes in moduli during 10 h at 10°C revealed retrogradation in the order of: field pea> kidney bean> chickpea> blackgram> pigeon pea starch. In blackgram and pigeon pea starches, the lower proportion of amylose plus intermediate fraction and higher proportion of short and long side chains of amylopectin are considered responsible for the higher crystallinity, gelatinization temperature and enthalpy of gelatinization.
First‐trimester uterine artery Doppler indices in term and preterm pre‐eclampsia
Authors: Melchiorre K. , Wormald B. , Leslie K. , Bhide A. , Thilaganathan B. 
Published: July 2008

AbstractObjectivesTo assess the relationship between first‐trimester uterine artery Doppler measurements and the development of term and preterm pre‐eclampsia.MethodsThis prospective study of uterine artery Doppler findings at 11–14 weeks in 3058 singleton pregnancies included 57 and 33 cases of term and preterm pre‐eclampsia, respectively.ResultsThe first‐trimester uterine artery resistance index (RI) was significantly higher in women who subsequently developed preterm pre‐eclampsia (mean RI, 0.79) than in those with a normal outcome (mean RI, 0.70; P = 0.0001) or those who developed pre‐eclampsia at term (mean RI, 0.72; P = 0.002). There were no significant differences in first‐trimester mean uterine artery RI (P = 0.136) or prevalence of bilateral notches (P = 0.459) between women who had a normal pregnancy outcome and those who developed pre‐eclampsia at term. The receiver–operating characteristics curves for the prediction of term and preterm pre‐eclampsia by uterine artery Doppler imaging demonstrated a significant association with development of preterm pre‐eclampsia (P = 0.0001; area under the curve (AUC), 0.76; 95% CI, 0.66–0.86) but not term pre‐eclampsia (P = 0.25; AUC, 0.54; 95% CI, 0.46–0.63).ConclusionsThe uterine artery Doppler data in this study suggest that preterm pre‐eclampsia is strongly associated with defective invasion of the spiral arteries, in contrast to the findings in term pre‐eclampsia which may be a consequence of placental deterioration at term. Our study findings support, but do not prove, a rigid separation between the etiology of early‐ and late‐onset pre‐eclampsia. Although there is a strong relationship between first‐trimester uterine artery Doppler indices and the subsequent development of preterm pre‐eclampsia, our data do not support its routine introduction into clinical practice. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Triage for surgical management of ovarian tumors in asymptomatic women: assessment of an ultrasound‐based scoring system
Authors: Alcázar J. L. , Royo P. , Jurado M. , Mínguez J. Á. , García‐Manero M. , Laparte C. , Galván R. , López‐García G. 
Published: July 2008

AbstractObjectivesTo prospectively evaluate an ultrasound‐based scoring system as a method for triaging asymptomatic women presenting with an adnexal mass for surgical treatment.MethodsTwo hundred and four adnexal masses in 189 asymptomatic women undergoing elective surgical treatment at our institution were included in this prospective study. Patients were evaluated by transvaginal power Doppler ultrasound imaging before surgery. Patients were classified as low risk or high risk for malignancy according to an ultrasound‐based scoring system. Women with a low risk for malignancy were scheduled for laparoscopy and patients with a high risk for malignancy were scheduled for laparotomy. However, patients classified as low risk by the ultrasound scoring system, but with a tumor size ≥ 10 cm or clinical suspicion of pelvic adhesions, were instead considered to be at intermediate risk and were scheduled for laparotomy. Some patients classified as high risk were scheduled for an operative laparoscopy by an expert in gynecological oncology.ResultsOne hundred and thirty‐four (65.7%) masses were considered to be low risk and were treated by a laparoscopically guided procedure. All these tumors were benign. Forty‐seven (23%) masses were classified as high risk, of which 39 tumors were malignant and eight benign. Twenty‐three (11.3%) tumors were considered to be intermediate risk and were scheduled for primary laparotomy. In this group, 21 (91.3%) tumors proved to be benign and two (8.7%) were malignant.ConclusionsUltrasound‐based triage of asymptomatic women diagnosed with a persistent adnexal mass is effective for selecting the surgical approach. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.