bluuebunny/crossref_metadata_2025_split huggingface dataset:
Online temperature measurement and simultaneous diameter estimation of fibers by thermography of the spinline in the melt spinning process
Authors: Golzar M. , Beyreuther R. , Brünig H. , Tändler B. , Vogel R. 
Published: July 2004

AbstractOnline measurements of the temperature and the diameter of fibers in the melt spinning process of thermoplastics are discussed. The temperature and the diameter of fibers can be applied in many fields such as fiber formation modelling, cooling rate behavior (Nusselt number), and rheological investigations (apparent extensional viscosity) of polymers. The online measurements along the spinline were carried out with an infrared camera during the melt spinning process. Two different experiments were designed and carried out to find the correction factor, i.e., the emissivity. The results show that the emissivity correction factor depends on the polymer type and the fiber diameter. Usually the diameter of the fibers is measured by an instrument or by direct velocity measurements invoking the continuity equation. In this new approach the diameter is found directly by the evaluation of the measured temperature. Therefore only one apparatus, namely an infrared camera taking snapshots, is required to find the fiber diameter. The key of this method can be seen in the temperature difference between the fiber and the environment. A mathematical procedure was developed to estimate the diameter of the fiber from the distribution curve. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 176–185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20008
A study of grafting reactions during processing of polyolefins
Authors: Machado A. V. , Covas J. A. , van Duin M. 
Published: July 2004

AbstractThe effects of polyolefins composition, that is polyethylene (PE), polypropylene (PP) and a ethylene/propylene copolymer (EPM) of 45/55 monomer ratio, and of operating conditions (screw speed, throughput and screw configuration) on the grafting of maleic anhydride (MA) were investigated. Sampling devices located along the extruder barrel were used to collect samples of modified PE, EPM, and PP that were subsequently characterized in order to monitor the degree of grafting and of crosslinking/degradation. Although a similar trend of MA grafting evolution is observed along the extruder, the final MA graft content depends on the processing parameters, screw configuration, and particularly, throughput have a significant effect on the grafting yield. Taking PE as an example, and by means of a statistical experimental design, an optimal operating window in terms of screw speed, throughput, and geometry was identified, yielding MA graft contents of 2 wt% MA. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 196–210, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20011
Reactive extrusion of poly(urethane‐isocyanurate)
Authors: Semsarzadeh M. A. , Navarchian A. H. , Morshedian J. 
Published: July 2004

AbstractReactive extrusion of poly(urethane‐isocyanurate) (PUIR) was studied in an intermeshing corotating twin‐screw extruder. Toluene diisocyanate (TDI) and polypropylene glycol (PPG) were used as initial materials with dibutyltin dilaurate (DBTDL) as catalyst. The reaction was first examined in a batch reactor as well as in an internal mixer in order to obtain the kinetics and temperature/torque evolution trends during the formation of PUIR, respectively. For the specified screw speed and temperature profile of the extruder, a working domain can be recommended for the reactive extrusion, in terms of NCO/OH ratio (r) and catalyst concentration (C), to reach a sufficient extent of reaction. The effects of screw speed and temperature profile on the residence time parameters of the reaction mixture were investigated. It is found that the axial mixing and the RTD behavior of the reaction mixture in the extruder can be well represented by the axial dispersion model. For the reaction condition of r = 3, C = 2%, and barrel temperature profiles of 75–150°C or 90–165°C, the optimum screw rotation speed for complete NCO conversion is 20 rpm. The structures, thermal stabilities, morphologies, and physical and dynamic mechanical properties of reactively extruded PUIRs were investigated. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 239–255, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20014
Breast cancer genetics: Unsolved questions and open perspectives in an expanding clinical practice
Authors: Hodgson Shirley V. , Morrison Patrick J. , Irving Melita 
Published: July 2004

AbstractBreast cancer is the most common cause of cancer death in the United Kingdom, with a lifetime risk of one in nine in women. Only 5–10% of all cancers is thought to be due to strongly penetrant inherited predisposing genes, such as BRCA1 and BRCA2. However, other less penetrant genes, including some autosomal recessive genes, are likely to be of etiological importance in other families. This review addresses the current knowledge of breast cancer susceptibility genes and explores the possibilities for future developments. Features of tumor pathology, prognosis, and the scope for targeted treatments in mutation carriers are discussed, and the management of known carriers and those at increased risk for developing breast cancer are evaluated. Genetic testing for cancer susceptibility may become widely available in the future, and has important ethical and management implications. © 2004 Wiley‐Liss, Inc.
Reduktion von N2O an einem μ4‐sulfidverbrückten vierkernigen aktiven CuZ‐Zentrum
Authors: Chen Peng , Gorelsky Serge I. , Ghosh Somdatta , Solomon Edward I. 
Published: June 2004

AbstractDie Reduktion von Distickstoffoxid (N2O) ist eine chemische Herausforderung, sowohl was die selektive Oxidation organischer Substrate durch N2O anbelangt als auch die Beseitigung von N2O als Treibhausgas. Die Reduktion von N2O ist thermodynamisch günstig, aber kinetisch gehemmt und erfordert die Aktivierung von N2O durch Übergangsmetallzentren. In biologischen Systemen ist die Reduktion von N2O der abschließende Denitrifizierungsschritt im bakteriellen Stickstoffkreislauf und wird von dem Enzym Distickstoff‐Reduktase katalysiert, dessen aktives Zentrum aus einem μ4‐sulfidverbrückten vierkernigen CuZ‐Cluster mit vielen ungewöhnlichen spektroskopischen Eigenschaften besteht. Aktuelle Untersuchungen führten zu einer detaillierten Beschreibung der elektronischen Struktur des CuZ‐Clusters im Ruhezustand und im katalytisch aktiven Zustand. Dies führt zum besseren Verständnis der Rolle dieses vierkernigen Kupferclusters bei der Aktivierung und Reduktion von N2O.
Semicontinuous emulsion copolymerization of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose (3‐MDG) and butyl acrylate (BA). Monomer feed addition
Authors: Al‐Bagoury Mohamed , Yaacoub Emile‐Joseph 
Published: June 2004

AbstractNew polymer colloids based on the saccharide monomer, using of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose (3‐MDG), were prepared by semicontinuous emulsion polymerization, a widely used industrial process. The copolymerization of 3‐MDG and butyl acrylate (BA), by the monomer‐addition technique, at 70°C, using sodium persulfate (Na2S2O8) as an initiator, was investigated. The influence of some reaction parameters, such as the type and concentration of the surfactants as well as the monomer addition rate (Rm) on the polymerization rate (Rp), the colloidal properties, and the stability of the latexes, was studied. It was found that under starved‐feed conditions the polymerization rate and the particle size (D) increased with an increasing rate of monomer addition. The weight‐average molecular weight (Mw) also increased by enhancing Rm and a narrower molecular weight distribution was obtained. Furthermore, the type and the concentration of the surfactants strongly influenced the particle size and its distribution. The effect of the seed stage on the particle size and its distribution was also investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2091–2102, 2003
The role of historical dolphin takes and habitat degradation in shaping the present status of northern Adriatic cetaceans
Authors: Bearzi Giovanni , Holcer Drasko , Notarbartolo di Sciara Giuseppe 
Published: June 2004

Abstract
Nine cetacean species have been reliably reported to occur in the shallow northern Adriatic Sea since the 17th century. However, only two species were considered regular there until the 1970s: the short‐beaked common dolphin (Delphinus delphis) and the common bottlenose dolphin (Tursiops truncatus).
Short‐beaked common dolphins have progressively disappeared from the northern Adriatic and are now rare in the region. The systematic culling campaigns and other takes that occurred between the second half of the 18th century and the 1960s, and habitat degradation in subsequent years are the most likely causes of their decline.
Today, common bottlenose dolphins are the only regular component of the northern Adriatic cetacean fauna; however, they now occur at low densities, and their fragmented groups are facing significant anthropogenic threats.
The future of northern Adriatic dolphins will depend on precautionary action to prevent further decline and on intensified research effort aimed at identifying the most effective mitigation strategies.
Copyright © 2004 John Wiley & Sons, Ltd.
A simple method for assessing minimum flows in regulated rivers: the case of sea lamprey reproduction
Authors: Oliveira João M. , Ferreira Maria T. , Pinheiro António N. , Bochechas Jorge H. 
Published: July 2004

Abstract
The sea lamprey (Petromyzon marinus) is an anadromous species that occurs in some large Iberian rivers, such as the Tagus, and their tributaries. The sea lamprey populations of the River Tagus are threatened by habitat loss and overexploitation, which means that conservation measures, including maintenance of the spawning grounds, are urgent. Habitat loss is mainly due to hydroelectric and flood‐control dams that have affected the migration and spawning habitats of anadromous species. The main objective of this study was to use a simple, cost‐effective method to assess a minimum instream flow for the regulated River Tagus. The method used was based on the wetted perimeter–discharge relationship, but accounted for the habitat requirements of spawning sea lampreys.
In 1998, a habitat survey was conducted along a 30 km segment of the River Tagus downstream from Belver Dam (the first impassable obstacle for fish movements), a stretch that includes potential habitats for spawning sea lampreys. Four spawning areas were identified, and in each one a representative reach was selected along which to collect elevation and geo‐positional data. For a range of flows from 0 to 50 m3 s−1, hydraulic modelling and studies of spawning habitat availability were conducted, both for each reach and for the total wetted area of the four reaches.
The availability of spawning habitat was limited by flow. Results showed that the present minimum flow downstream from Belver Dam (8 m3 s−1) is insufficient to ensure suitable habitat conditions in a significant part of the segment studied; gains in wetted usable area were more substantial with discharges of up to 20 m3 s−1, and thus a minimum flow of 10–20 m3 s−1 was recommended. Potential spawning habitat could be improved by increasing instream flow to at least 50 m3 s−1. The impacts of the Belver release regime on anadromous species are discussed and a more ‘ecologically oriented’ form of water management is suggested
. Copyright © 2004 John Wiley & Sons, Ltd.
Fish fauna in Iberian Mediterranean river basins: biodiversity, introduced species and damming impacts
Authors: Clavero Miguel , Blanco‐Garrido Francisco , Prenda José 
Published: July 2004

Abstract
A basin approximation was used to analyse distribution patterns of different components of biodiversity (taxonomic richness, endemicity, taxonomic singularity, rarity) and conservation status of freshwater fish fauna in 27 Mediterranean Iberian rivers.
Basin area alone explained more than 80% of variation in native species richness. Larger basins featured not only a higher number of native species, but also more endemic and rare species and fewer diversified genera than smaller basins.
In contrast, smaller basins scored higher community conservation values, owing to their lower degree of invasion by introduced species.
The presence of dams was the most important factor determining the conservation status of fish communities, and it was also positively associated with the number of introduced species.
While the most important components of Iberian freshwater fish biodiversity are located in large basins, small unregulated basins feature better conserved fish communities.
Copyright © 2004 John Wiley & Sons, Ltd.
Simultaneous Non‐inferiority Test of Sensitivity and Specificity for Two Diagnostic Procedures in the Presence of a Gold Standard
Authors: Chen James J. , Hsueh Huey‐miin , Liu Jen‐pei 
Published: June 2004

AbstractSensitivity and specificity have traditionally been used to assess the performance of a diagnostic procedure. Diagnostic procedures with both high sensitivity and high specificity are desirable, but these procedures are frequently too expensive, hazardous, and/or difficult to operate. A less sophisticated procedure may be preferred, if the loss of the sensitivity or specificity is determined to be clinically acceptable. This paper addresses the problem of simultaneous testing of sensitivity and specificity for an alternative test procedure with a reference test procedure when a gold standard is present. The hypothesis is formulated as a compound hypothesis of two non‐inferiority (one‐sided equivalence) tests. We present an asymptotic test statistic based on the restricted maximum likelihood estimate in the framework of comparing two correlated proportions under the prospective and retrospective sampling designs. The sample size and power of an asymptotic test statistic are derived. The actual type I error and power are calculated by enumerating the exact probabilities in the rejection region. For applications that require high sensitivity as well as high specificity, a large number of positive subjects and a large number of negative subjects are needed. We also propose a weighted sum statistic as an alternative test by comparing a combined measure of sensitivity and specificity of the two procedures. The sample size determination is independent of the sampling plan for the two tests.
Estimation of Additive Genetic Variance Components in Aquaculture Populations Selectively Pedigreed by DNA Fingerprinting
Authors: Li X. , Field C. , Doyle R. 
Published: June 2004

AbstractA method to estimate genetic variance components in populations partially pedigreed by DNA fingerprinting is presented. The focus is on aquaculture, where breeding procedures may produce thousands of individuals. In aquaculture populations the individuals available for measurement will often be selected, i.e. will come from the upper tail of a size‐at‐age distribution, or the lower tail of an age‐at‐maturity distribution etc. Selection typically occurs by size grading during grow‐out and/or choice of superior fish as broodstock. The method presented in this paper enables us to estimate genetic variance components when only a small proportion of individuals, those with extreme phenotypes, have been identified by DNA fingerprinting. We replace the usual normal density by appropriate robust least favourable densities to ensure the robustness of our estimates.Standard analysis of variance or maximum likelihood estimation cannot be used when only the extreme progeny have been pedigreed because of the biased nature of the estimates. In our model‐based procedure a full robust likelihood function is defined, in which the missing information about non‐extreme progeny has been taken into account. This robust likelihood function is transformed into a computable function which is maximized to get the estimates. The estimates of sire and dam additive variance components are significantly and uniformly more accurate than those obtained by any of the standard methods when tested on simulated population data and have desirable robustness properties.
How to Detect Biased Samples?
Authors: Navarro J. , Ruiz J.M. , del Aguila Y. 
Published: June 2004

AbstractIn this paper we study some methods to detect biased samples and to test what is the bias. These methods can be also used to obtain parametric tests for the original model. We pay special attention to the case of length (size) biased samples. We apply these results to several real and simulated samples.
Surface Plasmon Resonance Evaluation of Various Aminoglycoside–RNA Hairpin Interactions Reveals Low Degree of Selectivity
Authors: Verhelst Steven H. L. , Michiels Paul J. A. , van der Marel Gijsbert A. , van Boeckel Constant A. A. , van Boom Jacques H. 
Published: July 2004

AbstractAminoglycoside antibiotics, which are able to selectively bind to RNA, are considered to be an important lead in RNA‐targeting drug discovery. In this study, surface plasmon resonance (SPR) was employed to explore the interaction of aminoglycosides with known tobramycin‐binding RNA hairpins (aptamers) and an unrelated RNA hairpin. It was established that aminoglycosides have multiple interactions with RNA hairpins. Unexpectedly, the different hairpins showed comparable affinity for a set of related aminoglycosides. The observed absence of selectivity presents an extra hurdle in the discovery of novel aminoglycosides as specific drugs that target defined RNA hairpins.
A Mass Spectrometry Plate Reader: Monitoring Enzyme Activity and Inhibition with a Desorption/Ionization on Silicon (DIOS) Platform
Authors: Shen Zhouxin , Go Eden P. , Gamez Alejandra , Apon Junefredo V. , Fokin Valery , Greig Mike , Ventura Manuel , Crowell John E. , Blixt Ola , Paulson James C. , Stevens Raymond C. , Finn M. G. , Siuzdak Gary 
Published: July 2004

AbstractA surface‐based laser desorption/ionization mass spectrometry assay that makes use of Desorption/Ionization on Silicon Mass Spectrometry (DIOS‐MS) has been developed to monitor enzyme activity and enzyme inhibition. DIOS‐MS has been used to characterize inhibitors from a library and then to monitor their activity against selected enzyme targets, including proteases, glycotransferase, and acetylcholinesterase. An automated DIOS‐MS system was also used as a high‐throughput screen for the activity of novel enzymes and enzyme inhibitors. On two different commercially available instruments, a sampling rate of up to 38 inhibitors per minute was accomplished, with thousands of inhibitors being monitored. The ease of applying mass spectrometry toward developing enzyme assays and the speed of surface‐based assays such as DIOS for monitoring inhibitor effectiveness and enzyme activity makes it attractive for a broad range of screening applications.
Using Research to Evaluate Developmental Education Programs and Policies
Authors: Weissman Julie , Bulakowski Carole , Jumisko Marci K. 
Published: July 2004

AbstractHow do we know if a college' s remedial/developmental programs are effective in remediating students? Evaluation should go beyond simply determining whether courses are effective and should examine the placement of students, the timing of remediation, and the eventual student enrollment in college– level courses as measures of effectiveness.
Economic Benefits of a Community College Education: Issues of Accountability and Performance Measures
Authors: Sanchez Jorge R. , Laanan Frankie Santos 
Published: July 2004

AbstractAccountability in community colleges has taken center stage. This chapter focuses on students' post‐college earnings as a specific outcome or performance measure. The authors discuss the benefits of a community college education, outline the methodologies used to assess
students, and present policy implications of accountability and performance measures.
Stabilizing or Destabilizing Oligodeoxynucleotide Duplexes Containing Single 2′‐Deoxyuridine Residues with 5‐Alkynyl Substituents
Authors: Kottysch Thomas , Ahlborn Carolin , Brotzel Frank , Richert Clemens 
Published: June 2004

AbstractThe 5‐position of pyrimidines in DNA duplexes offers a site for introducing alkynyl substituents that protrude into the major groove and thus do not sterically interfere with helix formation. Substituents introduced at the 5‐position of the deoxyuridine residue of dU:dA base pairs may stabilize duplexes and reinforce helices weakened by a low G/C content, which would otherwise lead to false negative results in DNA chip experiments. Here we report on a method for preparing oligonucleotides with a 5‐alkynyl substituent at a 2′‐deoxyuridine residue by on‐support Sonogashira coupling involving the fully assembled oligonucleotide. A total of 25 oligonucleotides with 5‐alkynyl substituents were prepared. The substituents either decrease the UV melting point of the duplex with the complementary strand or increase it by up to 7.1 °C, compared with that of the unmodified control duplex. The most duplex‐stabilizing substituent, a pyrenylbutyramidopropyne moiety, is likely to intercalate but does not prevent sequence‐specific base pairing of the modified deoxyuridine residue or the neighboring nucleotides. It also increases the signal for a target strand when employed on a small oligonucleotide microarray. The ability to tune the melting point of a DNA dodecamer duplex with a single side chain over a temperature range of >11 °C may prove useful when developing DNA sequences for biomedical applications.
From NQR to NMR: The complete range of quadrupole interactions
Authors: Bain Alex D. , Khasawneh Maysoon 
Published: June 2004

AbstractThe theoretical transition energies of a spin 3/2 under a combination of quadrupolar and Zeeman interactions are mapped out as a function of magnetic field. This allows us to follow the spectroscopy continuously from zero magnetic field (NQR, nuclear quadrupole resonance) through to high magnetic field (quadrupole‐perturbed NMR). This calculation is made possible by a theoretical approach that makes maximum use of the angular momentum properties of the spin system. In this approach, the detailed form of the spin operators are not required, only their angular momentum quantum numbers. No commutators need be evaluated, and the method is easily coded for computer calculation. Application of the Wigner‐Eckart theorem and selection rules means that there are only two nonzero reduced matrix elements that are needed for a spin 3/2, and there are explicit formulae for them. In looking at the transition energies, the crucial parameter is the orientation of the quadrupole tensor to the magnetic field. If the angle is nonzero, then the quantization of the spins must shift. At zero field, the quantization is defined by the electric field gradient tensor, which is molecule‐fixed at some arbitrary angle to the magnetic field. This direction of quantization must change as the magnetic field increases, to lie close to the z axis at high field. In the region where the two interactions are comparable, all the familiar rules break down and the response is highly nonlinear. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part A 22A: 69–78, 2004.