bluuebunny/crossref_metadata_2025 huggingface dataset:
Upper flammability limits of some organosilicon compounds
Authors: Hshieh Fu‐Yu , Hirsch David B. , Williams James H. , Beeson Harold D.
Published: May 2004

This paper reports the upper flammability limits of 26 organosilicon compounds commonly used in the silicone industry and investigates the correlation between the upper flammability limit and the net heat of combustion. An empirical equation has been developed to predict the upper flammability limit of organosilicon compounds using the net heat of combustion. Copyright © 2004 John Wiley & Sons, Ltd.
Adaptive mesh refinement and coarsening for aerodynamic flow simulations
Authors: Scalabrin Leonardo Costa , Azevedo João Luiz F.
Published: May 2004

A new mesh refinement technique for unstructured grids is discussed. The new technique presents the important advantage of maintaining the original grid skewness, thanks to the capability of handling hanging nodes. The paper also presents an interpretation of MacCormack's method in an unstructured grid context. Results for a transonic convergent–divergent nozzle, for a convergent nozzle with a supersonic entrance and for transonic flow over a NACA 0012 airfoil are presented and discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Case‐control association studies with matching and genomic controlling
Authors: Lee Wen‐Chung
Published: May 2004

Family‐based association studies have gained in popularity for mapping disease‐susceptibility gene(s) of complex diseases. However, recruiting family controls is often more difficult than recruiting unrelated controls. The author proposes a case‐control study, where the possible biases due to population stratification are controlled by matching in the design stage and by genomic controlling in the data‐analytic stage. The matching is based on a set of “stratum‐delineating variables,” such as, race, ethnicity, nationality, ancestry, and birthplace; and the genomic controlling is based on typing a number of null markers across the genome and applying the principle of multiplicative scaling of chi‐square distribution. It pays to match carefully to have a higher proportion of correctly matched sets, as computer simulation showed that this would increase the power of the study. If matching is crude, one loses power but still has the correct type I error rate after genomic controlling. Power studies showed that the numbers of affected subjects required for the pair‐matched study are comparable to those required by the case‐parents design, if the study was conducted in a homogeneous population. As the (control‐to‐case) matching ratio increases, the number of affected subjects required decreases. With matching ratio tending toward infinity, the number required shrinks roughly by half. The case‐control study with matching and genomic controlling frees us from family bondage, and the genetic problem as complicated as mapping genes can now be studied using simple epidemiologic methods. © 2004 Wiley‐Liss, Inc.
Origin, age and petrogenesis of Neoproterozoic composite dikes from the Arabian‐Nubian Shield, SW Jordan
Authors: Jarrar G. , Saffarini G. , Baumann A. , Wachendorf H.
Published: May 2004

The evolution of a Pan‐African (c. 900–550 Ma) suite of composite dikes, with latite margins and rhyolite interiors, from southwest Jordan is discussed. The dikes cut the Neoproterozoic calc‐alkaline granitoids and high‐grade metamorphic rocks (c. 800–600 Ma) of the northern Arabian‐Nubian Shield in Jordan and have been dated by the Rb‐Sr isochron method at 566±7 Ma. The symmetrically distributed latite margins constitute less than one‐quarter of the whole dike thickness. The rhyolite intruded a median fracture within the latite, while the latter was still hot but completely solidified.

The dikes are alkaline and bimodal in composition with a gap in SiO2 between 61 and 74 wt%. Both end members display similar chondrite‐normalized rare earth element patterns. The rhyolites display the compositional signature of A‐type granites. The (La/Lu)N values are 6.02 and 4.91 for latites and rhyolites, respectively, and the rhyolites show a pronounced negative Eu anomaly, in contrast to the slight negative Eu anomaly of the latites. The chemical variability (e.g. Zr/Y, Zr/Nb, K/Rb) within and between latites and rhyolites does not support a fractional crystallization relationship between the felsic and mafic members of the dikes. We interpret the magma genesis of the composite dikes as the result of intrusion of mantle‐derived mafic magma into the lower crust in an extensional tectonic regime. The mafic magma underwent extensive fractional crystallization, which supplied the necessary heat for melting of the lower crust. The products of the initial stages of partial melting (5–10%) mixed with the fractionating mafic magma and gave rise to the latite melts. Further partial melting of the lower crust (up to 30%) produced a felsic melt, which upon 50% fractional crystallization (hornblende 15%, biotite 5%, feldspars 60%, and quartz 20%) gave rise to the rhyolitic magma. Copyright © 2004 John Wiley & Sons, Ltd.
Acritarchs from the Lower Palaeozoic succession on the south County Wexford coast, Ireland: new age constraints for the Cullenstown Formation and the Cahore and Ribband Groups
Authors: Brück P. M. , Vanguestaine M.
Published: May 2004

Lower Palaeozoic sediments crop out on the southern coast of County Wexford, Ireland, comprising three distinctive lithostratigraphical units: from west to east the Cahore Group, the Blackhall Formation of the Ribband Group and the Cullenstown Formation. The three units are largely devoid of macrofossils and thus their ages have to date been uncertain and, in the case of the Cullenstown Formation, speculative. In the Cahore Group, a diverse assemblage of acritarchs composed of seventeen species has been recorded indicating a middle Early Cambrian age. This is similar to the age of the lithologically identical Bray Group to the north, in County Wicklow. In the Ribband Group, two very distinct assemblages have been noted. Both are poorly preserved, but diagnostic species have been determined giving a biostratigrapical range of early Mid‐Cambrian to Llanvirn. Palynomorphs have been recorded for the first time from the Cullenstown Formation allowing comparison with eastern Newfoundland where a similar, less diverse assemblage has been recorded. The age indicated is latest Mid‐Cambrian to early Late Cambrian. Overall, despite generally poor preservation of the organic matter, some 45 acritarch species have been distinguished, among which one new combination is proposed: Retisphaeridium postae instead of Cymatiosphaera postae. Copyright © 2004 John Wiley & Sons, Ltd.
Concentrated albumin as a biological glue for hemorrhage control on hepatic resection with argon beam coagulation
Authors: Xie Hua , Wolf Ronald F. , Burke Allen P. , Gustafson Scott B. , Gregory Kenton W. , Prahl Scott A.
Published: May 2004

Topically applied concentrated albumin with argon beam coagulation (ABCA) has been shown to be more effective at achieving hemostasis than using argon beam coagulation alone (ABC) in a liver injury model. This study investigated the host response to the concentrated albumin after argon beam coagulation. Complete hemostasis was achieved using ABCA (N = 10) or ABC (N = 10) on a nonanatomic liver resection in a heparinized porcine model. The repairs were evaluated grossly and microscopically at postoperative periods of 30 and 90 days. We found no evidence of biliary leakage, rebleeding, or intraabdominal infection. Blood analysis indicated liver chemistry indices were within normal range after ABC and ABCA treatments. The histopathology showed that the postoperative healing response was similar in both groups: a moderate chronic inflammatory response as part of an on‐going normal healing process. All repairs were encapsulated by fibrous tissue. There was no difference in the postsurgical adhesion scores for the ABCA (mean 3.4) and ABC (mean 3.8). It was concluded that use of the concentrated albumin as biological glue in conjunction with argon beam coagulation is a safe and efficient procedure for controlling hepatic hemorrhage in surgery. Further studies are warranted to investigate the clinical significance of this technique. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 84–89, 2004
Effect of calcination temperature on catalyst reducibility and hydrogenation reactivity in rice husk ash–alumina supported nickel systems
Authors: Chang Feg‐Wen , Kuo Maw‐Suey , Tsay Ming‐Tseh , Hsieh Ming‐Chung
Published: May 2004

Nickel catalysts supported on rice husk ash–alumina (Ni/RHA–Al2O3) were prepared by an incipient wetness impregnation method. Characterization included TGA, DSC, TPR, XRD, and BET. Results show that the decomposition of the nickel compound to nickel oxide was complete above 500 °C. The TPR analysis revealed a strong interaction between nickel and support, and a decrease in reducibility of NiO with increasing calcination temperature. The XRD analysis of Ni/RHA–Al2O3 catalyst precursors demonstrated the presence of spinel. It also showed that the size of crystallites in the supported NiO first decreased with increase in calcination temperature up to 700 °C, and then increased due to phase transformation of nickel oxide to spinel. The pores are mesopores and their meshy surface structure was not affected by calcination temperature in the range investigated. The catalytic activity was tested by CO2 hydrogenation with an H2/CO2 ratio of 4/1 at 500 °C. The CO2 conversion and CH4 yield for CO2 hydrogenation over 15 wt% Ni/RHA–Al2O3 catalyst were almost independent of calcination and reduction temperatures. Copyright © 2004 Society of Chemical Industry
Determination of α‐conotoxin binding modes on neuronal nicotinic acetylcholine receptors
Authors: Dutertre Sébastien , Nicke Annette , Tyndall Joel D. A. , Lewis Richard J.
Published: May 2004

α‐Conotoxins, from cone snails, and α‐neurotoxins, from snakes, are competitive inhibitors of nicotinic acetylcholine receptors (nAChRs) that have overlapping binding sites in the ACh binding pocket. These disulphide‐rich peptides are used extensively as tools to localize and pharmacologically characterize specific nAChRs subtypes. Recently, a homology model based on the high‐resolution structure of an ACh binding protein (AChBP) allowed the three‐fingered α‐neurotoxins to be docked onto the α7 nAChR. To investigate if α‐conotoxins interact with the nAChR in a similar manner, we built homology models of human α7 and α3β2 nAChRs, and performed docking simulations of α‐conotoxins ImI, PnIB, PnIA and MII using the program GOLD. Docking revealed that α‐conotoxins have a different mode of interaction compared with α‐neurotoxins, with surprisingly few nAChR residues in common between their overlapping binding sites. These docking experiments show that ImI and PnIB bind to the ACh binding pocket via a small cavity located above the β9/β10 hairpin of the (+)α7 nAChR subunit. Interestingly, PnIB, PnIA and MII were found to bind in a similar location on α7 or α3β2 receptors mostly through hydrophobic interactions, while ImI bound further from the ACh binding pocket, mostly through electrostatic interactions. These findings, which distinguish α‐conotoxin and α‐neurotoxin binding modes, have implications for the rational design of selective nAChR antagonists. Copyright © 2004 John Wiley & Sons, Ltd.
Study of meteorological and hydrological drought in southern Romania from observational data
Authors: Stefan Sabina , Ghioca Monica , Rimbu Norel , Boroneant Constanta
Published: May 2004

The spatial and temporal variability of the river discharges and precipitation from the southern part of Romania for 69 years, during the period 1931–99, is investigated. The study is based on river discharges (precipitation) data recorded at ten hydrometric and six meteorological stations from this region.

The cross‐correlation analysis reveals a seasonal dependence of the lag time between the precipitation and river discharge anomalies, being larger (2–3 months) in winter than in summer (0–1 month). The correlation and the EOF analyses reveal consistent interannual to decadal variations for precipitation and river discharges. In particular, persistent meteorological and hydrological droughts were identified during 1943–52, 1958–68 and 1980–99.

A composite analysis reveals that high (low) values of the river discharge and precipitation in this region are related to a large‐scale atmospheric circulation pattern similar to the negative (positive) phase of the North Atlantic oscillation (NAO). This suggests that, during periods of persistent positive phase of NAO, persistent meteorological and hydrological drought conditions are expected in the southern part of Romania with important consequences on the climate and economy of this region. Copyright © 2004 Royal Meteorological Society
Global analysis of runs of annual precipitation and runoff equal to or below the median: run length
Authors: Peel Murray C. , Pegram Geoffrey G. S. , Mcmahon Thomas A.
Published: May 2004

The investigation of fluctuations of wet and dry years has a long history in the climatology and hydrology literature. In this, the first of two papers investigating runs of consecutive dry years, the lengths (persistence) of dry runs are investigated. In the second paper the magnitude/intensity and severity (length × magnitude) of dry runs will be investigated. Consecutive dry years are associated with drought, which is a significant physical and economic phenomenon that imposes great stress on ecosystems and societies. Run lengths of consecutive years equal to or below the median were analysed for 3863 precipitation and 1236 runoff stations from around the world. Run lengths were found to be similar across all continents and Köppen climate zones, expect for tropical and arid North Africa (Sahel), which showed a distinct bias toward longer run lengths than any other region of the world. Generally, the run length observed in annual runoff was found to be similar to that observed in annual precipitation for the same location. Both annual precipitation and runoff data were found to be well described by the lag‐one autoregressive (AR(1)) model or by white noise. The influence of the El Niño–southern oscillation on run lengths was not observed to be significant. The presence of decadal and multi‐decadal oscillations was weakly observed in the results of the precipitation runs analysis. The faintness of the decadal and multi‐decadal oscillation signal may be due to the sample sizes not being long enough and/or the runs analysis not being sensitive enough to detect their presence. Copyright © 2004 Royal Meteorological Society
What happens when things go wrong? Retail sales explanations and their effects
Authors: Dunning Jarrad , Pecotich Anthony , O'Cass Aron
Published: May 2004

Not all marketplace interactions are initially successful, and often customer expectations are not met, resulting in dissatisfaction, which leads to complaint and redress‐seeking behavior. In this process, the nature of the explanations and other aspects of the firm–customer interaction are critical. This study investigates the proposition that explanation adequacy plays a critical role in the resolution of unsatisfactory sales encounters. Data were collected from a sample of consumers and analyzed with the use of structural‐equation modeling. The findings indicate that explanation adequacy is influenced by the style and content of the explanation and the timeliness of an organization's reaction. However, explanation adequacy appears to only influence the final perceptions (indirectly) of the severity of the incident and emotional reaction to it, and the perceptions of the extent of the justice of the resolution and the assignment of blame to external factors were found to be intervening variables. The results also indicated that the assignment of blame to internal factors was unrelated to the adequacy of an explanation, but did influence emotional reactions and the perceived severity of the incident. © 2004 Wiley Periodicals, Inc.
From black sheep to aspiring business partner: HR's turnaround at Delaware investments
Authors: Hutcheson Joanne
Published: May 2004

Delaware Investments' human resources function, barely able to meet even the most basic needs of the growing company, was hamstrung by inadequate resources, tools, and expertise. New leadership helped the HR team envision a new role for itself and undertake a five‐year effort to redesign its processes, leverage technology, implement self‐service, create partnerships, and develop the competencies to become a strategic partner in the business. © 2004 Wiley Periodicals, Inc.
Six Sigma helps a company create a culture of accountability
Authors: Brewer Peter C.
Published: May 2004

How do you make employees feel more accountable for results? With many opinions but no hard facts about how to achieve this, one company turned to Six Sigma to find the answer. Six Sigma methodology, no longer confined to production departments, helped this company discover that a culture of accountability, first and foremost, is a function of strategically aligned employee expectations and an effective system of rewards and consequences. © 2004 Wiley Periodicals, Inc.
Post‐marketing surveillance of buprenorphine
Authors: Ray Rajat , Pal Hemraj , Kumar Rajesh , Maulick Pallab , Mangla R.
Published: May 2004

Purpose

This study was undertaken to evaluate the adverse consequences of recently introduced higher strength (0.4 and 2.0 mg per tablet) buprenorphine in Indian market. Buprenorphine, a partial opiate agonist and antagonist, is an emerging alternative to methadone as an agent for long‐term treatment of opiate dependence.

Methods

The current investigation was conducted through a multi‐centric post‐marketing surveillance (PMS)study using a structured performa from patients receiving buprenorphine as routine therapy from de‐addiction centres. Evaluation included subjective and objective assessments and recording of adverse events.

Results

Of the 5551 observations from ten centres, common subjective symptoms were generalised weakness (48.9%), sense of high (euphoria) (44.5%), muscle aches (39.5%) and relief from pain (37.2%). About 5% observations recorded systolic hypertension. Among 55 subjects where laboratory tests were conducted, 12 showed raised levels of AST ad 9 had elevated ALT. Twelve adverse events reported included seizure, epistaxis, panic attacks, constipation and dyspnoea. Significant relation was seen between duration of use and time since last dose, and total number of subjective symptoms reported.

Conclusions

Majority of the adverse effects could be understood as either effects related to intoxication or withdrawal from agonists. Copyright © 2004 John Wiley & Sons, Ltd.
Composite droplets with core/shell morphologies prepared from HDPE/PS/PMMA ternary blends by twin‐screw extrusion
Authors: Tchomakov Kiril P. , Favis Basil D. , Huneault Michel A. , Champagne Michel F. , Tofan Florin
Published: May 2004

Ternary blends of PS and PMMA in a PE matrix were prepared by twin‐screw extrusion to investigate the core/shell encapsulation phenomenon in the composite droplet. The PS was found to encapsulate the PMMA to form composite droplets within the PE matrix as expected from the spreading coefficient theory. The effects of dispersed phase concentration, viscosity ratio, feeding sequence and twin‐screw operating conditions were investigated. The blend morphology was observed by scanning electron microscopy after selective extraction of either PS or PMMA, and average core and composite droplet diameters were determined by image analysis. Although it is known that the structure of composite droplet blends can be substantially altered through control of the volume fraction of the components in the dispersed phase, this study demonstrates that blends with a 1:1 composite droplet volume fraction are relatively stable to large variations in the minor phase viscosities and processing conditions. Twin‐screw extrusion thus provides a highly robust technique for the melt processing of blends possessing composite droplet morphologies. Polym. Eng. Sci. 44:749–759, 2004. © 2004 Society of Plastics Engineers.
Real‐time monitoring of fluorescence anisotropy and temperature during processing of biaxially stretched polypropylene film
Authors: Bur Anthony J. , Roth Steven C.
Published: May 2004

An optical sensor based on fiber optics has been developed to measure fluorescence anisotropy and temperature during processing of biaxially stretched polypropylene films. The sensor, containing optical fibers, polarizing elements and lenses, was mounted above the polypropylene film as it was processed in a tenter frame oven stretching machine. Fluorescence observations were made using the fluorescent dye, bis (di‐tert butylphenyl) perylenedicarboximide (BTBP), which was doped into the resin at very low concentrations. To monitor biaxial stretching, fluorescence anisotropy measurements were carried out with light polarized in the machine and the transverse directions corresponding to the directions of biaxial stretching. Fluorescence based temperature measurements were obtained from the ratio of fluorescence intensities at 544 nm and 577 nm. A matrix of experiments involving three levels of stretch ratio in both the machine and transverse directions was undertaken. We observed significant differences between anisotropy in the machine and transverse directions that we attributed to the sequential stretching operation, i.e., the film was stretched in the machine direction first, followed by stretching in the transverse direction, and to film temperature and strain rate for each stretching operation. The result was uniformly higher anisotropies in the machine direction. Film temperature obtained from fluorescence corresponded to oven thermocouple measurements within 2°C. Polym. Eng. Sci. 44:805–813, 2004. © 2004 Society of Plastics Engineers.
Are cognitive differences between immigrant and majority groups diminishing?
Authors: te Nijenhuis Jan , de Jong Mart‐Jan , Evers Arne , van der Flier Henk
Published: May 2004

A review is given of scores on various cognitive measures, comparing groups of ethnic Dutch and non‐Western immigrants using a large number of datasets.

The research shows that there are large group differences in school results, work proficiency, and g for Turks, Moroccans, Surinamese, Netherlands Antilleans, and Indonesians from the Moluccans compared with ethnic Dutch. However, South‐East Asians score higher, and persons with one immigrant and one ethnic Dutch parent score only slightly below the mean of the Dutch. When comparing first‐generation disadvantaged immigrant groups with later generations the data show substantial improvements for g, a remarkable stability of educational differences for younger children, and a clear improvement in educational achievement at the end of primary school. Indirect data on intergenerational improvements in work proficiency appear suggestive of a trend of closing gaps.

Some of the data reflect higher cognitive capacities over time, and this enhances integration of immigrants into Dutch society. Causes of group differences and improvements in mean level of g are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Factors associated with short‐term clinical outcomes after acute treatment of asthma in a pediatric emergency department
Authors: Benito‐Fernández Javier , Onis‐González Estibaliz , Álvarez‐Pitti Julio , Capapé‐Zache Susana , Vázquez‐Ronco Miguel A. , Mintegi‐Raso Santiago
Published: May 2004

Outcomes of emergency room treatment of children with asthma have not been well‐documented. The purpose of this study was to describe the short‐term clinical course of children aged 0–14 years after standard treatment for an acute asthma exacerbation in a pediatric emergency department, and to determine factors associated with follow‐up morbidity. This was a prospective cohort study of a randomly selected sample of children with asthma who required treatment for an acute asthma exacerbation during the year 2002. A clinical chart was filled out by the attending pediatrician during the emergency department visit. Participants were interviewed by telephone at 7 and 15 days after the pediatric emergency visit. The study population included 258 children; 125 of them (48.4%) were <2 years old. Eighty‐nine percent of children reported a visit with his/her primary asthma care provider during the first week after discharge from the emergency department. A total of 185 children missed 1 or more days of school, with a mean of 3.1 ± 2.7 days (range, 1–23 days). Twenty‐nine patients (11%) returned for medical care at the emergency department, 22 (8.5%) of them during the first week after discharge, and 4 (1.6%) required hospitalization. At the first follow‐up control (day 7), 111 patients (43%) reported persistent symptoms and/or difficult breathing, and 157 (61%) were still using asthma medication. At the second follow‐up control (day 15), 53 patients (20.5%) reported persistent respiratory symptoms, and 69 (26.7%) used asthma medication. In children >2 years of age, the percentage of patients with respiratory symptoms on day 7 was significantly lower among those who reported maintenance therapy with inhaled steroids (23.7% vs. 46%, P = 0.006). On day 7, asthma symptoms were more frequent in children <2 years of age compared to older children showed a higher percentage of asthma symptoms (50% vs. 36%, P = 0.014). Children <2 years old compared to older children also missed more days school or day nursery (4.48 ± 4.62 days vs. 2.4 ± 2.19 days). The short‐term outcome of asthma children attended at the emergency department is worse than expected, according to rates of rehospitalization and return for medical care after discharge. Maintenance treatment with inhaled steroids favored a prompt recovery in children older than 2 years of age, whereas the short‐term outcome of children aged <2 years was not influenced by any variable. Pediatr Pulmonol. © 2004 Wiley‐Liss, Inc.
A structural pattern‐based method for protein fold recognition
Authors: Taylor William R. , Jonassen Inge
Published: May 2004

A method (SPREK) was developed to evaluate the register of a sequence on a structure based on the matching of structural patterns against a library derived from the protein structure databank. The scores obtained were normalized against random background distributions derived from sequence shuffling and permutation methods. ‘Random’ structures were also used to evaluate the effectiveness of the method. These were generated by a simple random‐walk and a more sophisticated structure prediction method that produced protein‐like folds. For comparison with other methods, the performance of the method was assessed using collections of models including decoys and models from the CASP‐5 exercise. The performance of SPREK on the decoy models was equivalent to (and sometimes better than) those obtained with more complex approaches. An exception was the two smallest proteins, for which SPREK did not perform well due to a lack of patterns. Using the best parameter combination from trials on decoy models, the CASP models of intermediate difficulty were evaluated by SPREK and the quality of the top scoring model was evaluated by its CASP ranking. Of the 14 targets in this class, half lie in the top 10% (out of around 140 models for each target). The two worst rankings resulted from the selection by our method of a well‐packed model that was based on the wrong fold. Of the other poor rankings, one was the smallest protein and the others were the four largest (all over 250 residues). Proteins 2004. © 2004 Wiley‐Liss, Inc.
Free energy surfaces of β‐hairpin and α‐helical peptides generated by replica exchange molecular dynamics with the AGBNP implicit solvent model
Authors: Felts Anthony K. , Harano Yuichi , Gallicchio Emilio , Levy Ronald M.
Published: May 2004

We have studied the potential of mean force of two peptides, one known to adopt a β‐hairpin and the other an α‐helical conformation in solution. These peptides are, respectively, residues 41–56 of the C‐terminus (GEWTYDDATKTFTVTE) of the B1 domain of protein G and the 13 residue C‐peptide (KETAAAKFERQHM) of ribonuclease A. Extensive canonical ensemble sampling has been performed using a parallel replica exchange method. The effective potential employed in this work consists of the OPLS all‐atom force field (OPLS‐AA) and an analytical generalized Born (AGB) implicit solvent model including a novel nonpolar solvation free energy estimator (NP). An additional dielectric screening parameter has been incorporated into the AGBNP model. In the case of the β‐hairpin, the nonpolar solvation free energy estimator provides the necessary effective interactions for the collapse of the hydrophobic core (W43, Y45, F52, and V54), which the more commonly used surface‐area‐dependent nonpolar model does not provide. For both the β‐hairpin and the α‐helix, increased dielectric screening reduces the stability of incorrectly formed salt bridges, which tend to disrupt the formation of the hairpin and helix, respectively. The fraction of β‐hairpin and α‐helix content we obtained using the AGBNP model agrees well with experimental results. The thermodynamic stability of the β‐hairpin from protein G and the α‐helical C‐peptide from ribonuclease A as modeled with the OPLS‐AA/AGBNP effective potential reflects the balance between the nonpolar effective potential terms, which drive compaction, and the polar and hydrogen bonding terms, which promote secondary structure formation. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Adjacent cysteines are capable of ligating the same tetranuclear iron–sulfur cluster
Authors: Gurrath Marion , Friedrich Thorsten
Published: May 2004

The mechanism of the energy‐converting NADH (β‐nicotinamide adenine dinucleotide, reduced form):ubiquinone oxidoreductase, which is also called respiratory complex I, is largely unknown due to lack of a high‐resolution structure and the most complicated construction of the enzyme. Electron transport is carried out by one flavin mononucleotide (FMN) and up to 9 Fe/S clusters. The Fe/S cluster N2, which is believed to be directly involved in redox‐coupled proton‐translocation, is located on subunit NuoB (the homologue of the mitochondrial PSST subunit). This subunit contains a conserved binding motif for a [4Fe/4S] cluster with two adjacent cysteines. It was questioned whether these adjacent cysteines could be ligands of the same cluster due to a possible steric hinderance. However, mutagenesis of either of these cysteines led to a loss of cluster N2. We used the known structure of the homologous small subunit of hydrogenases containing a regular cysteine motif to generate an in silico mutant with two consecutive cysteines. Molecular dynamics simulation showed that the conformation of these cysteines does not meet the topological requirements for coordination of a [4Fe/4S] cluster when the protein backbone conformation is kept constant. In comparison, the simulation of a dipeptide amide using a “template forcing” approach resulted in a conformation compatible to an optimal coordination of the two cluster positions in question. Thus, a slight main‐chain conformational change would allow two adjacent cysteines to coordinate a [4Fe/4S] cluster. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Function‐dependent clustering of orthologues and paralogues of cyclophilins
Authors: Galat Andrzej
Published: May 2004

The 18 kDa archetypal cyclosporin‐A binding protein, cyclophilin‐A, has multiple paralogues in the human genome. Only 18 of those paralogues have been detected as mRNAs or proteins whose masses vary from 18 to 354 kDa, whereas the functional significance of the open reading frames (ORFs) encoding other paralogues of cyclophilin‐A remains unknown. The genomes ofDrosophila melanogaster,Caenorhabditis elegans,Arabidopsis thaliana,Schizosaccharomyces pombe, andSaccharomyces cerevisiaeencode different numbers of the cyclophilin paralogues, some of which are orthologous to the human cyclophilins. A library of novel algorithms was developed and used for computation of the conservation levels for hydrophobicity and bulkiness profiles, and amino acid compositions (AACs) of 303 aligned sequences of cyclophilins. The majority of the paralogues and orthologues encoded in these 6 genomes differ considerably from each other. Some of the orthologues and paralogues have high correlation coefficients (CCFs) for pairwise compared hydrophobicity and bulkiness profiles, and whose AACs differ to a low degree. Convergence of these three properties of the polypeptide chain and apparent conservation of the typical sequence hallmarks and parameters allowed for the clustering of the functionally related orthologues and paralogues of the cyclophilins. The clustering method allowed for sorting out the cyclophilins into several distinct classes. Analyses of the overlapping clusters of sequences permitted delineation of some hypothetical pathways that might have led to the creation of certain paralogues of cyclophilins in the eukaryotic genomes. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Protein contact prediction using patterns of correlation
Authors: Hamilton Nicholas , Burrage Kevin , Ragan Mark A. , Huber Thomas
Published: May 2004

We describe a new method for using neural networks to predict residue contact pairs in a protein. The main inputs to the neural network are a set of 25 measures of correlated mutation between all pairs of residues in two “windows” of size 5 centered on the residues of interest. While the individual pair‐wise correlations are a relatively weak predictor of contact, by training the network on windows of correlation the accuracy of prediction is significantly improved. The neural network is trained on a set of 100 proteins and then tested on a disjoint set of 1033 proteins of known structure. An average predictive accuracy of 21.7% is obtained taking the best L/2 predictions for each protein, where L is the sequence length. Taking the best L/10 predictions gives an average accuracy of 30.7%. The predictor is also tested on a set of 59 proteins from the CASP5 experiment. The accuracy is found to be relatively consistent across different sequence lengths, but to vary widely according to the secondary structure. Predictive accuracy is also found to improve by using multiple sequence alignments containing many sequences to calculate the correlations. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Effect of glycosylation on the structure of Erythrina corallodendron lectin
Authors: Kulkarni K. A. , Srivastava A. , Mitra N. , Sharon N. , Surolia A. , Vijayan M. , Suguna K.
Published: May 2004

The three‐dimensional structure of the recombinant form of Erythrina corallodendron lectin, complexed with lactose, has been elucidated by X‐ray crystallography at 2.55 Å resolution. Comparison of this non‐glycosylated structure with that of the native glycosylated lectin reveals that the tertiary and quaternary structures are identical in the two forms, with local changes observed at one of the glycosylation sites (Asn17). These changes take place in such a way that hydrogen bonds with the neighboring protein molecules in rECorL compensate those made by the glycan with the protein in ECorL. Contrary to an earlier report, this study demonstrates that the glycan attached to the lectin does not influence the oligomeric state of the lectin. Identical interactions between the lectin and the non‐covalently bound lactose in the two forms indicate, in line with earlier reports, that glycosylation does not affect the carbohydrate specificity of the lectin. The present study, the first of its kind involving a glycosylated protein with a well‐defined glycan and the corresponding deglycosylated form, provides insights into the structural aspects of protein glycosylation. Proteins 2004. © 2004 Wiley‐Liss, Inc.
An improved thin‐layer chromatography/mass spectrometry coupling using a surface sampling probe electrospray ion trap system
Authors: Ford Michael J. , Van Berkel Gary J.
Published: May 2004

A combined surface sampling probe/electrospray emitter coupled with an ion trap mass spectrometer was used for the direct read out of unmodified reversed‐phase C18 thin‐layer chromatography (TLC) plates. The operation of the surface sampling electrospray ionization interface in positive and negative ionization modes was demonstrated through the direct analysis of TLC plates on which a commercial test mix comprised of four dye compounds viz., rhodamine B, fluorescein, naphthol blue black, and fast green FCF, and an extract of the caffeine‐containing plant Ilex vomitoria, were spotted and developed. Acquisition of full‐scan mass spectra and automated collection of MS/MS product ion spectra while scanning a development lane along the surface of a TLC plate demonstrated the advantages of using an ion trap in this combination. Details of the sampling system, benefits of analyzing a developed lane in both positive ion and negative ion modes, levels of detection while surface scanning, surface scan speed effects, and the utility of three‐dimensional data display, are also discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Development and validation of an isotope‐dilution electrospray ionization tandem mass spectrometry method with an on‐line sample clean‐up device for the quantitative analysis of the benzene exposure biomarker S‐phenylmercapturic acid in human urine
Authors: Lin Lung‐Cheng , Tyan Yu‐Chang , Shih Tung‐Sheng , Chang Yu‐Chen , Liao Pao‐Chi
Published: May 2004

An isotope‐dilution electrospray ionization tandem mass spectrometry (ESI‐MS/MS) method with an on‐line sample clean‐up device, for the quantitative analysis of human urine for the benzene exposure biomarker S‐phenylmercapturic acid (SPMA), was developed and validated. The sample clean‐up system was constructed from an autosampler, a reversed‐phase C18 trap cartridge, a two‐position switching valve, and controlling computer software and hardware. The sample clean‐up system was interfaced via 1/20 splitting to the ESI source of a triple‐quadrupole mass spectrometer using negative ion mode and multiple reaction monitoring for SPMA and the isotope‐labeled internal standard. A strategy was adopted to acquire pooled blank urine matrix and quality control samples spiked with standards. Validated procedures and data on method specificity, detection limits, standard curves, precision and recovery, sample storage stability, and inter‐laboratory comparison are presented. The analytical system was fully automated. No tedious manual sample clean‐up procedures are required. With the selectivity and the sensitivity provided by ESI‐MS/MS detection, the analytical system can be used for high‐throughput and accurate determination of SPMA levels in human urine samples, as a biomarker for environmental as well as occupational benzene exposure. Copyright © 2004 John Wiley & Sons, Ltd.
Clinical Diagnosis of Metastatic Gastric Tumors: Clinicopathologic Findings and Prognosis of Nine Patients in a Single Cancer Center
Authors: Kobayashi Osamu , Murakami Hitoshi , Yoshida Tatsuya , Cho Haruhiko , Yoshikawa Takaki , Tsuburaya Akira , Sairenji Motonori , Motohashi Hisahiko , Sugiyama Yuka , Kameda Yoichi
Published: May 2004

The clinical features of metastatic gastric tumors (MGTs) have not been well documented. We present a clinical series of nine patients with MGTs. Among 2579 patients with gastric tumors seen between 1992 and 2001, we studied 9 (0.3%) patients with MGT according to a prospective database. The MGTs were diagnosed based on findings in the surgical or endoscopic specimen, and patients with malignant lymphoma or direct invasion from adjacent organs were excluded from the study. MGTs were detected simultaneously with the primary tumors in three and afterward in six patients at 14 to 74 months. The primary tumors included one each of squamous cell carcinoma of the esophagus, signet‐ring cell carcinoma of the breast, large‐cell or small‐cell carcinoma of the lung, renal cell carcinoma, hepatocellular carcinoma, squamous cell or epidermoid carcinoma of the uterus, and melanoma. Multiple organ metastases were present simultaneously in six patients. Although six patients underwent gastrectomy, macroscopic eradication of gastric metastatic disease was accomplished in only four, in whom a UICC R0 resection was possible in only two. Five patients were treated by chemotherapy with no apparent survival benefit. A median survival after MGT diagnosis was 170 days (range 16‐892 days) for all cases, 384 days for those who underwent gastrectomy (n = 6), and 27 days for those without active treatment (n = 3) (p = 0.002). The cause of death was multiple organ metastases in most cases. Because multiple metastases are common, the prognosis of MGT is poor even after curative resection. MGT is likely to be a preterminal event, and surgical resection may be useful only for palliation.
Evaluation of Intraoperative Recurrent Nerve Monitoring in Thyroid Surgery
Authors: Beldi Guido , Kinsbergen Thomas , Schlumpf Rolf
Published: May 2004

Surgical exposure of the recurrent laryngeal nerve decreases the incidence of nerve injuries during thyroid surgery. Intraoperative neuromonitoring was introduced to facilitate identification and protection of the recurrent laryngeal nerve. Between February 1996 and June 2002 a total of 288 patients underwent thyroid surgery with intraoperative identification and intraoperative neuromonitoring of the recurrent laryngeal nerve. The overall incidences of permanent and transient recurrent nerve palsy (considered as a percentage of the nerves at risk) were 1.4% and 8.7%, respectively. Results were stratified in benign, malignant, and recurrent thyroid disease. Intraoperative function testing revealed a positive predictive value of 33% and negative predictive value of 99%. We concluded that the incidence of recurrent nerve lesions in benign, malignant, and recurrent thyroid disease was not lowered by the use of intraoperative neuromonitoring. Although an intact nerve can be verified by the neuromonitoring, the loss of nerve function cannot be reliably identified.
Congenital Bilateral Renal Arteriovenous Malformation: An Unrecognized Cause of Renal Failure
Authors: Riedlinger Wolfram F.J. , Kissane John M. , Gibfried Matthew , Liapis Helen
Published: May 2004

Congenital renal arteriovenous malformations (AVM) are very rare abnormal communications between arteries and veins. These lesions are almost always unilateral, predominantly in the right kidney, and usually asymptomatic until adulthood. We present a unique case of bilateral renal AVM in a 10-year-old white boy who developed renal failure requiring renal transplantation. Microscopic sections of an atrophic right and a slightly larger left kidney with tortuous and dilated hilar vessels showed elaborate derangement of arteries and veins insinuating between lobules. Glomeruli were diffusely enlarged with increased number of capillary loops. Glomerular basement membrane reduplication and fibrinoid necrosis was focally noted. Electron microscopy demonstrated absence of electron-dense deposits or mesangial interposition excluding membranoproliferative glomerulonephritis. We believe that the glomerular lesions are secondary to congenital renal arteriovenous malformation. To our knowledge, bilateral arteriovenous malformation in infancy is not previously described.
Vaginal birth after cesarean section: management debate
Authors: Chattopadhyay K. , Sengupta B.S. , Edress Y.B. , Lambourne A.
Published: May 2004

Obstetric performance of 1847 women with previous cesarean section (CS) during the years 1983 and 1984 were studied. Vaginal birth after cesarean section (VBAC) was attempted in 94% of females with one previous CS, 4% in those with two previous CS, and one among the 70 patients with three or more previous CS. VBAC was achieved in 51% of those with one previous CS. It was successful in 60% of parturients with CS for non‐recurrent causes, 36% of CS for cephalopelvic disproportion (CPD) and in 64% of those with a prior vaginal delivery. Uterine scar dehiscence was found in 0.9% of all patients with a previous CS. A failed attempt with Ventouse to achieve VBAC caused maximum maternal and perinatal morbidity.
Intrapartum levels of trace metals in maternal blood in relation to umbilical cord blood values: Lead, iron, copper, zinc
Authors: Sikorski R. , Paszkowski T. , Milart P. , Radomanski Jr T. , Szkoda J.
Published: May 2004

The study was designed to measure the gradients of lead, iron, copper and zinc from maternal blood to cord blood in pregnant urban and rural women. The concentrations of iron, copper, zinc and lead were measured by means of atomic absorption spectometry (AAS) in whole blood of 100 normal parturients and 92 of their neonates. Levels of lead in cord blood were not significantly different from those in maternal blood. This ratio was associated with similar iron and zinc ratios. Neonatal birth weight was negatively correlated with maternal copper levels, whereas cord blood zinc values positively correlated with placental weight. Rural women showed higher maternal to cord blood lead ratios than urban women. The implications of these findings are discussed.
The hemoglobinopathies and pregnancy in Lagos
Authors: Ogedengbe O.K. , Akinyanju O.O.
Published: May 2004

Thirty‐four patients with abnormal hemoglobin were studied through 42 pregnancies under one obstetrician. There were 30 patients with sickle cell anemia (HbSS), two with sickle cell hemoglobin C disease (HbSC) and two with homozygous hemoglobin C disease (HbCC). There were 39 live births (including one pair of twins), and four perinatal deaths. The patients with HbSC and HbCC had five uncomplicated pregnancies and deliveries. Of the 36 pregnancies in patients with HbSS one aborted at 12 weeks. Intra‐uterine growth retardation (14.3%) and pregnancy‐induced hypertension (14.3%) were the most serious pregnancy complications. No patient had more than one crisis. Only one out of the 10 patients transfused needed more than two units of blood throughout pregnancy. The mean gestation at delivery was 37.5 ± 3.2 (S.D.) weeks. The mean birth weight was 2.7 ± 0.6 (S.D.) kg. The perinatal mortality was 114.3 per thousand live births and there was one maternal death.
Prevalence of urinary incontinence in middle‐aged women
Authors: Iosif C.S. , Békássy Z. , Rydhström H.
Published: May 2004

An anonymous questionnaire was used to interview 946 premenopausal women (age 29–52 years), previously either hysterectomized or laparoscopically sterilized, concerning disorders of the urinary tract. Of the 750 (79.3%) women that responded, 307 (40.9%) admitted to some degree of urinary disorder. The prevalence of urinary disorders was 170/415 (40.9%) for the women with a previous supravaginal or total hysterectomy and 137/335 (40.8%) for the women in the sterilization group. Of the responding women 85 (11.3%) experienced a urinary loss sufficient to necessitate the wearing of a sanitary napkin or change of underclothing several times a day.
Carcinoma of the cervix uteri in Zaria: etiological factors
Authors: Emembolu J.O. , Ekwempu C.C.
Published: May 2004

The study conducted at Ahmadu Bello University Teaching Hospital, Zaria from January to December, 1984 showed that carcinoma of the cervix uteri occurred in 4.18% of new gynecological attendances; 68.9% of the cases occurred in the age range 40–55 years. Early age at marriage (80.0), and at first pregnancy (77.8%) as well as multiple marriages (48.9%) and low contraceptive usage were identifiable associated factors. The parity of the patient did not seem to be of significance. The earliest presenting symptom was post‐coital bleeding occurring 10.8 months prior to attendance for medical advice. However, late presentation (in Stages IIb–IV) in 86.7% of cases was due to illiteracy, shyness, male dominance and non‐recognition of the importance of early warning symptoms.