bluuebunny/crossref_metadata_2025_split huggingface dataset:
A finite‐sample hierarchical analysis of wage variation across public high schools: evidence from the NLSY and high school and beyond
Authors: Tobias Justin L. , Li Mingliang 
Published: June 2003

AbstractUsing data from both the National Longitudinal Survey of Youth (NLSY) and High School and Beyond (HSB), we investigate if public high schools differ in the “production” of earnings and if rates of return to future education vary with public high school attended. Given evidence of such variation, we seek to explain why schools differ by proposing that standard measures of school “quality” as well as proxies for community characteristics can explain the observed parameter variation across high schools. Since analysis of widely‐used data sets such as the NLSY and HSB necessarily involves observing only a few students per high school, we employ an exact finite sample estimation approach. We find evidence that schools differ and that most proxies for high school quality play modest roles in explaining the variation in outcomes across public high schools. We do find evidence that the education of the teachers in the high school as well as the average family income associated with students in the school play a small part in explaining variation at the school‐level. Copyright © 2002 John Wiley & Sons, Ltd.
Recalcitrant soil organic materials mineralize more efficiently at higher temperatures
Authors: Bol Roland , Bolger Thomas , Cully Raymond , Little Declan 
Published: June 2003

AbstractAs concentrations of atmospheric CO2increase, it is important to know whether this may result in feedbacks that could modify the rate of increase of CO2in the atmosphere. Soil organic matter (SOM) represents one of the largest pools of C and mineralization rates are known to be temperature dependent. In this study, we investigated whether different OM fractions present in a forest soil (F/A1 horizon) would respond in a similar manner to elevated temperatures. We examined the trends in isotopic content (12C,13C, and14C) of soil respired CO2at various temperatures (10, 20, and 350C) over a two year period in the laboratory. We also examined the total C, total N, and C : N ratio in the remaining soil and isolated humic fractions, and the distribution of the individual amino acids in the soil after 5 years of laboratory incubation at the various temperatures. We found that the rate at which C mineralization increases with temperature was occasionally greater than predicted by most models, more C from recalcitrant OM pools being mineralized at the higher temperature. This confirmed that the relationship between soil organic matter decomposition and temperature was complex and that the different pools of organic matter did respond in differing ways to elevated temperatures.
Preparation and characteristics of nitrile rubber (NBR) nanocomposites based on organophilic layered clay
Authors: Kim Jin‐tae , Oh Taeg‐su , Lee Dong‐ho 
Published: June 2003

AbstractThe effect of clay modification on organo‐montmorillonite/NBR nanocomposites has been studied. Organo‐montmorillonite/NBR nanocomposites were prepared through a melt intercalation process. NBR nanocomposites were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), dynamic mechanical thermal analysis (DMTA) and a universal testing machine (UTM). XRD showed that the basal spacing in the clay increased, which means that the NBR matrix was intercalated in the clay layer galleries. On TEM images, organo‐montmorillonite (MMT) particles were clearly observed, having been exfoliated into nanoscale layers of about 10–20 nm thickness from their original 40 µm particle size. These layers were uniformly dispersed in the NBR matrix. The DMTA test showed that for these nanocomposites the plateau modulus and glass transition temperature (Tg) increased with respect to the corresponding values of pure NBR (without clay). UTM test showed that the nanocomposites had superior mechanical properties, ie strength and modulus. These improved properties are due to the nanoscale effects and strong interactions between the NBR matrix and the clay interface. Copyright © 2003 Society of Chemical Industry
Optimized condition for grafting reaction of poly(butyl acrylate) onto oil palm empty fruit bunch fibre
Authors: Ibrahim NA , Yunus WMZ Wan , Abu‐Ilaiwi FAF , Rahman MZA , Ahmad MB , Dahlan KZM 
Published: June 2003

AbstractPreparation of poly(butyl acrylate)‐grafted oil palm empty fruit bunch fibre (OPEFB) has been successfully carried out using H2O2/Fe2+ as a redox initiator in aqueous solution. The effects of reaction temperature and period, as well as the amount of monomer, initiator and nitric acid, on the percentage of grafting were investigated. The percentage of grafting increases with amount of monomer and can be controlled by setting the appropriate reaction conditions. The maximum percentage of grafting (about 265%) was obtained when the reaction was carried out without acid under optimum conditions (reaction period: 2 h, reaction temperature: 55 °C, amount of H2O2: 5.88 mmol) with 42.2 mmol of monomer. Mechanisms of grafting of butyl acrylate onto OPEFB were proposed. Characterization of the grafted OPEFB was done by Fourier‐transform infrared spectroscopy and scanning electron microscopy. The thermal properties were studied by thermogravimetric analysis. Copyright © 2003 Society of Chemical Industry
Improved proteome analysis of Saccharomyces cerevisiae mitochondria by free‐flow electrophoresis
Authors: Zischka Hans , Weber Gerhard , Weber Peter J. A. , Posch Anton , Braun Ralf J. , Bühringer Dietmute , Schneider Ulrich , Nissum Mikkel , Meitinger Thomas , Ueffing Marius , Eckerskorn Christoph 
Published: June 2003

AbstractThe analysis of complex cellular proteomes by means of two‐dimensional gel electrophoresis (2‐DE) is significantly limited by the power of resolution of this technique. Although subcellular fractionation can be a fundamental first step to increase resolution, it frequently leads to preparations contaminated with other cellular structures. Here, we chose mitochondria of Saccharomyces cerevisiae to demonstrate that an integrated zone‐electrophoretic purification step (ZE), with a free‐flow electrophoresis device (FFE), can assist in overcoming this problem, while significantly improving their degree of purity. Whereas mitochondrial preparations isolated by means of differential centrifugation include a considerable degree of non‐mitochondrial proteins (16%), this contamination could be effectually removed by the inclusion of a ZE‐FFE purification step (2%). This higher degree of purity led to the identification of many more proteins from ZE‐FFE purified mitochondrial protein extracts (n = 129), compared to mitochondrial protein extracts isolated by differential centrifugation (n = 80). Moreover, a marked decrease of degraded proteins was found in the ZE‐FFE purified mitochondrial protein extracts. It is noteworthy that even at a low 2‐DE resolution level, a four‐fold higher number (17 versus 4) of presumably low abundance proteins could be identified in the ZE‐FFE purified mitochondrial protein extracts. Therefore these results represent a feasible approach for an in‐depth proteome analysis of mitochondria and possibly other organelles.
Matrix‐assisted laser desorption/ionization‐ quadrupole ion trap‐time of flight mass spectrometry sequencing resolves structures of unidentified peptides obtained by in‐gel tryptic digestion of haptoglobin derivatives from human plasma proteomes
Authors: Koy Cornelia , Mikkat Stefan , Raptakis Emmanuel , Sutton Chris , Resch Martin , Tanaka Koichi , Glocker Michael O. 
Published: June 2003

AbstractTwo‐dimensional gel electrophoresis‐separated and excised haptoglobin α2‐chain protein spots were subjected to in‐gel digestion with trypsin. Previously unassigned peptide ion signals observed in mass spectrometric fingerprinting experiments were sequenced using the matrix‐assisted laser desorption/ionization‐quadrupole ion trap‐time of flight (MALDI‐QIT‐TOF) mass spectrometer and showed that the haptoglobin α‐chain derivative under study was cleaved by trypsin unspecifically. Abundant cleavages occurred C‐terminal to histidine residues at H23, H28, and H87. In addition, mild acidic hydrolysis leading to cleavage after aspartic acid residues at D13 was observed. The uninterpreted tandem mass spectrometry (MS/MS) spectrum of the peptide with ion signal at 2620.19 was submitted to database search and yielded the identification of the corresponding peptide sequence comprising amino acids (aa) aa65–87 from the haptoglobin α‐chain protein. Also, the presence of a mixture of two tryptic peptides (mass to charge ratio m/z 1708.8; aa40–54, and aa99–113, respectively), that is caused by a tiny sequence variation between the two repeats in the haptoglobin α2‐chain protein was resolved by MS/MS fragmentation using the MALDI‐QIT‐TOF mass spectrometer instrument. Advantageous features such as (i) easy parent ion creation, (ii) minimal sample consumption, and (iii) real collision induced dissociation conditions, were combined successfully to determine the amino acid sequences of the previously unassigned peptides. Hence, the novel mass spectrometric sequencing method applied here has proven effective for identification of distinct molecular protein structures.
The effect of oxidation or alkylation on the separation of wool keratin proteins by two‐dimensional gel electrophoresis
Authors: Plowman Jeffrey E. , Flanagan Leanne M. , Paton Louise N. , Fitzgerald Anna C. , Joyce Nigel I. , Bryson Warren G. 
Published: June 2003

AbstractComparative two‐dimensional electrophoretic (2‐DE) studies were performed over a time‐course to examine the effect of oxidation or alkylation on the separation of wool keratin proteins. The effect of oxidation was followed by treating scoured wool fibres with increasing levels of hydrogen peroxide, ranging from 0–12 g/L, using conditions mimicking the industrial wool bleaching process. Peroxide treatment was found to have only a minor effect on the 2‐DE separation of the intermediate filament protein (IFP) class. Conversely, peroxide treatment of the 24–28 kDa high sulphur protein (HSP) class, which contains up to 40 cysteine residues per protein, resulted in the gradual disappearance of the major HSP spots correlated with the appearance of a few discrete spots at lower isoelectric point (pI). This suggested that only a few specific cysteine residues were being oxidized to cysteic acid by treatment with hydrogen peroxide. Peroxide treatment also appeared to have affected a discrete number of cysteine residues among proteins in the high glycine‐tyrosine protein (HGTP) class, reducing the intensity of the high pI spots, while correspondingly increasing the intensity of those at lower pI. In a separate study, wool proteins were alkylated with iodoacetamide (1 M, pH 8) for periods ranging from 10 min to 48 h. In contrast to treatment with peroxide, the pI values of the HSP spots were unaffected by alkylation, irrespective of the length of this treatment. Alkylation resulted in a shift to lower pI and a loss of resolution of individual spots in the Type I and II IFP trains, to the extent that after 24 h alkylation individual spots in these trains merged. In addition after 1 h the intensity of the high pI Type II IFPs decreased until they were no longer visible on the 2‐DE map after 24 h. Similarly as alkylation time increased, the major, high pI HGTP spots decreased in intensity. In unison with their decrease, some of the lower pI spots increased in intensity, while new spots appeared at more acidic pIs. Mass spectral studies indicated that cysteine alkylation was relatively fast, with 70–95% of the cysteines in the keratin proteins being alkylated within the first 10 min, while in the case of the HGTPs there was evidence for noncysteine alkylation occurring within this period. Alkylation of proteins for periods of up to 6 h prior to electrofocusing is being promoted as a better alternative to the current 2‐DE protocol of the inclusion of a reductant in the immobilized pH gradient rehydration solution. This study has clearly demonstrated that long alkylation times do not suit all protein types or classes.
Parents' decision‐making preferences in pediatric oncology: The relationship to health care involvement and complementary therapy use
Authors: Gagnon Elizabeth M. , Recklitis Christopher J. 
Published: June 2003

AbstractThis study investigated how parents' preferred level of control in treatment decision‐making is related to their personal health care involvement and to their decision to use complementary therapies (CTs) for their child. One hundred‐eighteen parents of pediatric oncology patients completed an anonymous CT survey. The Krantz Health Opinion Survey (KHOS) was used to determine parents' preferred involvement in personal health care, and the Control Preferences Scale for Pediatrics (CPS‐P) measured preferred role in pediatric treatment decision‐making. Unlike previous studies of adult cancer patients, most parents preferred active or collaborative decision‐making. The KHOS and CPS‐P were significantly correlated, indicating that parents' preferred role in children's treatment decisions was related to their own personal health care involvement. Forty‐six percent of parents used CTs for their child, and 33% began using a new CT after diagnosis. The hypothesized relationship between CT use and parents' own health care involvement was partially supported. Preference for control in decision‐making was not associated with CT use. These findings provide validation for the newly developed CPS‐P and indicate that parents' decisions to use CT for their child are related in part to individual health care preferences. Copyright © 2003 John Wiley & Sons, Ltd.
Interventions to improve access to health and social care after discharge from hospital: a systematic review
Authors: Richards Suzanne , Coast Joanna 
Published: June 2003

Objectives: To determine the effectiveness and costs of interventions intended to improve access to health and social care for older patients following discharge from acute hospitals. Method: Systematic literature review, following NHS Centre for Reviews and Dissemination guidelines, of randomised controlled trials evaluating needs assessment methods and patient discharge co-ordinator roles. These services targeted patients aged 60 years and over and varied depending on whether or not they selected frail patients (e.g. those at risk of needing nursing home care). Outcomes assessed included: referrals to or use of health and social care (15 studies); mortality (13 studies); patients' functional health status and disability (13 studies); and patient perceptions of health (five studies), quality of life (three studies), cognitive functioning and psychological well-being (ten studies), social support (two studies) and the adequacy of services (four studies). Results: Fifteen randomised controlled trials (23 papers), mainly from the USA, were identified. The interventions provided and patient groups targeted by these services were heterogeneous. There was, however, some evidence that services combining needs assessment, discharge planning and a method for facilitating the implementation of these plans were more effective than services that do not include the latter action. Conclusions: The assessment of need may be insufficient in itself for the adequate provision of post-discharge care. Needs assessment should be combined with a service that facilitates the implementation of care plans.
The view of the General Medical Council
Authors: Chantler Cyril , O'Brien Jane 
Published: June 2003

Information about a patient's health is recorded in order to provide for that patient's care. Most patients will not think about the other uses for their data and many assume that the information they provide will go no further than the health care professionals who have been caring for them. Information collected about patients is essential for developments in our understanding of health and health care. Most patients will be happy to allow their data to be used for these purposes, once this has been explained. Health care professionals have an obligation to ensure that patients know when identifiable data about them are to be used and to get their agreement about making disclosures. We know that this is not easily achieved; doctors, nurses and others providing care are already over-stretched. Patients may be anxious about their condition and treatment. They may not, for a variety of reasons, read leaflets or letters sent or given to them. This does not mean our obligations to respect patients by keeping them informed and seeking their agreement can be ignored. Openness about how health care professionals work and partnership with patients are essential to the continued trust of the public in the professions. The challenge is not to answer the question whether we need consent but rather how we can best obtain it.
Neue Methoden zur Bildung von (E)‐Alken‐Einheiten in makrocyclischen Naturstoffen
Authors: Prunet Joëlle 
Published: June 2003

Abstract(E)‐Alken‐Einheiten sind ein häufiges Strukturmerkmal in natürlichen Makrocyclen. Zu den Reaktionen, die im Zuge einer Cyclisierung Doppelbindungen aufbauen können, gehört die klassische Horner‐Emmons‐Kupplung, die noch immer oft genutzt wird. Während des letzten Jahrzehnts haben sich Ringschluss‐Metathesen als besonders nützlich zur Synthese großer Ringe erwiesen, aber die selten vorhersagbare E/Z‐Selektivität hängt von vielen Faktoren ab, die in diesem Kurzaufsatz beschrieben werden. Die beste Lösung könnte ein zweistufiges Verfahren mit einer Ringschluss‐Alkinmetathese und nachfolgender stereoselektiver Reduktion der makrocyclischen Alkin‐Einheit zum Isomer mit E‐Doppelbindung sein.
Soluble and conductive polypyrrole copolymers containing silicone tegomers
Authors: Kızılcan Nilgün , Ustamehmetoğlu Belkıs , Öz Nesrin , Sezai Saraç A. , Akar Ahmet 
Published: June 2003

AbstractSoluble and processable conductive copolymers of silicone tegomers and pyrrole were developed. This was easily accomplished by the oxidative polymerization of pyrrole monomer by Ce(IV) salt in the presence of silicone tegomers with hydroxyl chain ends. The resulting copolymers were soluble in dimethylformamide. The products were characterized by Fourier transform infrared, 1H‐NMR, and four‐point probe conductivity, and their surface properties were investigated with contact‐angle measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2896–2901, 2003
Novel amine preaccelerators for polyester resins
Authors: Kucharski Mieczysław , Duliban Jerzy , Chmiel‐Szukiewicz Elżbieta 
Published: June 2003

AbstractThe reactions between N,N‐dimethyl‐p‐phenylenediamine and ethylene or propylene oxide were carried out to obtain 3‐[p‐(N,N‐dimethylamino)phenyl]‐3‐azapentane‐1,5‐diol and 4‐[p‐(N,N‐dimethylamino)phenyl]‐4‐azaheptane‐2,6‐diol, respectively. The structures of the products were determined using elemental analysis, 1H‐NMR and IR spectroscopy techniques. The diols were incorporated into unsaturated polyester resins. The time of gelation and stability of the resins was observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2973–2976, 2003
Association of fluorescent probes 1‐anilinonaphthalene‐8‐sulfonate and 4,4′‐dianilino‐1,1′‐binaphthyl‐5,5′‐disulfonic acid with T7 RNA polymerase
Authors: Ghosh Utpal , Das Mili , Dasgupta Dipak 
Published: June 2003

AbstractT7 RNA polymerase is an enzyme that carries out transcription using DNA as the template and ribonucleotides as the substrates. Here we report the association of the polymerase with 1‐anilinonaphthalene‐8‐sulfonate (ANS) and 4,4′‐dianilino‐1,1′‐binaphthyl‐5,5′‐disulfonic acid (bis‐ANS), which are two fluorescent hydrophobic probes that are frequently used to study structural perturbations in proteins and intermediate states of proteins during folding and unfolding. Our results from the fluorescence titration data show that these two molecules bind to the enzyme with dissociation constants on the micromolar order. The results from the tryptic digestion of the enzyme in the absence and presence of the probes show that they inhibit the rate of tryptic digestion. Circular dichroism spectroscopic studies of the protein in the near UV region indicate that both probes induce tertiary structural changes in the polymerase. There is also a probe (ANS or bis‐ANS) induced inhibition of the enzymatic activity. All these results are attributed to association of the probes with the enzyme, leading to an alteration in the conformation of T7 RNA polymerase. This limits the use of these extrinisic probes to the study of the folding properties of the enzyme. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy), 2003
Raman microspectroscopic study of effects of Na(I) and Mg(II) ions on low pH induced DNA structural changes
Authors: Muntean C. M. , Segers‐Nolten G. M. J. 
Published: June 2003

AbstractIn this work a confocal Raman microspectrometer is used to investigate the influence of Na+ and Mg2+ ions on the DNA structural changes induced by low pH. Measurements are carried out on calf thymus DNA at neutral pH (7) and pH 3 in the presence of low and high concentrations of Na+ and Mg2+ ions, respectively. It is found that low concentrations of Na+ ions do not protect DNA against binding of H+. High concentrations of monovalent ions can prevent protonation of the DNA double helix. Our Raman spectra show that low concentrations of Mg2+ ions partly protect DNA against protonation of cytosine (line at 1262 cm−1) but do not protect adenine and guanine N(7) against binding of H+ (characteristic lines at 1304 and 1488 cm−1, respectively). High concentrations of Mg2+ can prevent protonation of cytosine and protonation of adenine (disruption of AT pairs). By analyzing the line at 1488 cm−1, which obtains most of its intensity from a guanine vibration, high magnesium salt protect the N(7) of guanine against protonation. A high salt concentration can prevent protonation of guanine, cytosine, and adenine in DNA. Higher salt concentrations cause less DNA protonation than lower salt concentrations. Magnesium ions are found to be more effective in protecting DNA against binding of H+ as compared with calcium ions presented in a previous study. Divalent metal cations (Mg2+, Ca2+) are more effective in protecting DNA against protonation than monovalent ions (Na+). © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 72: 000–000, 2003
Synthesis and characterization of 2,3‐di‐O‐alkylated amyloses: Hydrophobic substitution destabilizes helical conformation
Authors: Breitinger Hans‐Georg 
Published: June 2003

AbstractAmylose was selectively alkylated in the 2,3‐O position of each anhydroglucose unit after trityl protection of the 6‐OH groups. Alkyl iodides of varying chain length (C2, C5, C8) were coupled to amylose, and degrees of substitution (DSs) were varied between 0.3 and 1.8, as assessed by NMR analysis. Increasing amounts of methyl groups per anhydroglucose unit increased solubility in nonaqueous media, while at the same time reducing the ability of modified amylose to form a complex with iodine. The tendency to form inclusion complexes with the surfactant N‐dodecyl pyridinium bromide decreased in the order β‐cyclodextrin ≫ amylose ∼ solubilized starch, indicating that the frozen macrocycle of β‐cyclodextrin was the most efficient inclusion host. Introduction of the bulky trityl group abolished the helical amylose conformation, which is not readily reassumed in the presence of hydrophobic substitution of the C2 and C3 positions. These results indicated that a polar outer surface is necessary but not sufficient for the formation of a stable amylose helix. © 2003 Wiley Periodicals, Inc. Biopolymers 69: 301–310, 2003