bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural and spectral studies on gypsum crystals under simulated conditions of phosphoric acid production with and without organic and inorganic additives
Authors: Rashad M. M. , Baioumy H. M. , Abdel‐Aal E. A. 
Published: June 2003

AbstractIn the dihydrate process to produce phosphoric acid, phosphate ore [Ca10F2(PO4)6] is leached with sulfuric and weak phosphoric acids to produce phosphoric acid and gypsum as a by‐product. Crystallization of gypsum occurs as the leaching is taking place. The effect of organic and inorganic additives on the structure and spectrum of gypsum crystals under simulated conditions of phosphoric acid production is studied using x‐ray diffraction and infrared spectroscopy. Structure and spectrum of formed gypsum crystals in the absence of additives are slightly different from the standard gypsum crystals (card No. 6‐0046), which reflect the effect of preparation medium on the crystal structure of gypsum crystals. Presence of additives such as cetyl trimethyl ammonium bromide and 1,2‐dihydroxybenzene‐3,5‐disulfonic acid, Al3+ and Mg2+ increase the crystallinity of gypsum, while presence of additives such as citric acid and sodium dodecyl sulfate decrease the crystallinity of gypsum. Presence of Al3+ and Mg2+ as additives lead to the formation of calcium sulfate hemihydrate beside calcium sulfate dihydrate. Presence of sodium dodecyl sulfate as an additive inhibits the crystallization of gypsum and leads to the formation of anhydrite and calcium sulfate hemihydrate.
X‐ray interferometric investigation of homogeneity of substances
Authors: Drmeyan H. R. 
Published: June 2003

AbstractThe influence of inhomogeneous distribution of substance density on interference patterns of X‐rays is investigated. It is shown experimentally that during preliminary transition of superposing Roentgen waves through samples with inhomogeneous distribution of substance density, irregular phase shifts occur in these waves, leading to disappearance of interference patterns. Special two‐ and three crystal interferometers are developed for such investigations.
Optical and opto‐electronic properties of polycrystalline Cd0.96Zn0.04Te thin films
Authors: Sridharan M. , Narayandass Sa. K. , Mangalaraj D. , Lee Hee Chul 
Published: June 2003

AbstractCd0.96Zn0.04Te thin films are deposited onto thoroughly cleaned glass substrates (Corning 7059) kept at room temperature by vacuum evaporation. The films are found to have good stoichiometry as analyzed by Rutherford Backscattering Spectrometry. The films exhibited zinc blende structure with predominant (111) orientation. The surface morphology of the films is studied by Atomic Force Microscopy. The rms roughness of the films evaluated by AFM is 3.7 nm. The pseudodielectric‐function spectra, ε(E) = ε1(E) + i ε2(E) at room temperature are measured by spectroscopic ellipsometry. The measured dielectric function spectra reveal distinct structures at energies of the E1, E1+ Δ1 and E2 critical points. The band gap energy of the films measured by optical transmittance measurement is 1.523 eV. The PL spectrum of the films shows intense emission due to free and bound exciton recombination and no emission associated with crystal imperfection and deeper impurity levels. The PL line shapes give indications of the high quality of the layers.
Negative T cell costimulation and islet tolerance
Authors: Gao Wenda , Demirci Gülçin , Li Xian Chang 
Published: June 2003

AbstractActivation of self‐reactive T cells that specifically destroy the pancreatic β‐cells is one of the hallmarks in the development of type 1 diabetes. Thus, for prevention and treatment of this autoimmune disease, approaches to induce and maintain T cell tolerance toward the β‐cells, especially in islet transplantation, have been actively pursued. Noticeably, many of the recent protocols for inducing transplant tolerance involve blockade of positive T cell costimulation extrinsically. Though highly effective in prolonging graft survival, these strategies alone might not be universally sufficient to achieve true tolerance. As the mystery of the suppressive and regulatory T cells unfolds, it is becoming appreciated that exploiting the intrinsic molecular and cellular mechanisms that turn off an immune response would perhaps facilitate the current protocols in establishing T cell tolerance. In this perspective, here we summarize the recent findings on the negative costimulation pathways, in particular, the newly identified PD‐1 : PD‐L interactions. On the basis of these observations, we propose a new principle of curtailing pathogenic T cell response in which blockade of positive T cell costimulation is reinforced by concurrent engagement of the negative costimulation machinery. Such a strategy may hold greater hope for therapeutic intervention of transplant rejection and autoimmune diseases. Copyright © 2003 John Wiley & Sons, Ltd.
Prevalence of psychiatric disorders in an onset cohort of adults with type 1 diabetes
Authors: Petrak Frank , Hardt Jochen , Wittchen Hans‐Ulrich , Kulzer Bernhard , Hirsch Axel , Hentzelt Frieder , Borck Katrin , Jacobi Frank , Egle Ulrich Tiber , Hoffmann Sven Olaf 
Published: June 2003

AbstractBackgroundPrevious studies indicate a high prevalence of psychiatric disorders in adults with type 1 diabetes mellitus. The aim of our study was to determine if newly diagnosed adults with type 1 diabetes already have an elevated rate of psychiatric disorders at the beginning of their physical illness.MethodsThe authors consecutively recruited 313 newly diagnosed, adult inpatients with type 1 diabetes (age 17–40 years) from 12 hospitals. A national, representative population sample of 2046 persons of a similar age range served as the reference group. Psychiatric disorders were measured in both groups using structured interviews that provided diagnoses according to DSM‐IV.ResultsThere was a point prevalence of 12.5% for psychiatric disorders in the sample. The most frequent conditions were anxiety and affective disorders. Subjects with type 1 diabetes demonstrated a rate of major depressive episodes twice that of the reference group (5.8% vs 2.7%, p < 0.003; corrected for confounders). Apart from this finding, there was no significantly increased prevalence of psychiatric disorders in the diabetes sample as compared to the general German population.ConclusionThe rate of major depressive episodes in the new onset cohort of type 1 diabetes patients was double that of the population as a whole. However, the hypothesis, that newly diagnosed type 1 diabetes patients have more psychiatric disorders than the general population, was not confirmed. Copyright © 2003 John Wiley & Sons, Ltd.
Spot volume vs. amount of protein loaded onto a gel: A detailed, statistical comparison of two gel electrophoresis systems
Authors: Zhan Xianquan , Desiderio Dominic M. 
Published: May 2003

AbstractThe long‐term goal of this research program is to clarify the molecular mechanisms that participate in the formation of human pituitary macroadenomas. One approach to that goal is to characterize the differentially expressed proteins that are found by a comparison of the proteomes of control pituitary vs. macroadenoma tissues. In order to accurately perform a comparative proteomics study, based on the combination of two‐dimensional polyacrylamide gel electrophoresis (2‐D PAGE) and PDQuest 2‐D analysis software, a reproducible 2‐DE separation system with a wide linear dynamic measure range is needed. A typical horizontal system is the Multiphor II system that analyzes one gel at a time, using a precast gradient gel (180×245×0.5 mm); a typical vertical system is the Dodeca system that analyzes up to 12 gels at a time on a single‐concentration gel (190×205×1.0 mm). We have evaluated (Zhan and Desiderio, Electrophoresis 2003, 24, 1834–1846) the spatial and quantitative reproducibility of the two second‐dimensional gel systems to separate a human pituitary proteome; that study showed a higher reproducibility for the Dodeca gel system. This present study investigated the relationship between the spot volume and the amount of protein loaded onto the gel for those two 2‐D systems. The results demonstrated that the Dodeca gel system provides a wider linear dynamic range to measure the changes in the protein abundance in pituitary proteome.
Anthracycline‐dependent heat‐induced transition from positive to negative supercoiled DNA
Authors: Víglasky Viktor , Valle Francesco , Adamčík Jozef , Joab Irene , Podhradsky Dušan , Dietler Giovanni 
Published: May 2003

AbstractThe conformational stability of individual DNA topoisomers depends on the concentration of DNA intercalating drugs. To study the DNA‐drug interaction, we used ethidium bromide (EtBr) and negative supercoiled pUC19 as a model system. The effects of two anthracyclines widely used in cancer therapy, daunorubicin (Dau) and doxorubicin (Doxo), and EtBr were compared. In spite of their different chemical structures and intercalation mode, all intercalating agents show similar effects on the conformational stability of supercoiled DNA. Our observations show that the studied intercalators have at least two main effects on the supercoiled DNA: (i) they decrease the level of negative supercoiling and, at certain concentrations, they may induce positive supercoiling in DNA; (ii) a temperature increase can cause a recovery of negative supercoiling in DNA. The conformational stability of plasmid DNA‐drug complexes has been investigated by temperature gradient gel electrophoresis (TGGE). We demonstrate the suitability of TGGE for this purpose, because it offers a global view on DNA‐drug complexes over a continuous range of temperature. Images of DNA plasmids adsorbed onto a substrate at different temperatures and drug concentrations were acquired by atomic force microscopy (AFM), allowing us to distinguish directly the conformation chirality assumed by the plasmid under different conditions confirming TGGE results. Our detection system allows to characterize unknown drugs and to determine their intercalating properties.
Differences in the spatial and quantitative reproducibility between two second‐dimensional gel electrophoresis systems
Authors: Zhan Xianquan , Desiderio Dominic M. 
Published: May 2003

AbstractTwo‐dimensional polyacrylamide gel electrophoresis (PAGE), together with 2‐D gel electrophoresis (GE) analysis software, is a common technique to analyze a complex proteome. In order to accurately locate the differentially expressed proteins in human pituitary macroadenoma tissues in our long‐term research program to clarify the molecular mechanisms of macroadenoma formation, a reproducible separation system is needed. An immobilized pH‐gradient dry gel‐strip (IPG strip) has been extensively used for first‐dimensional isoelectric focusing (IEF), and has achieved a high degree of reproducibility in the IEF direction. For the second dimension (SDS‐PAGE), different types of gel systems are available, including horizontal vs. vertical gel systems, and gradient vs. constant‐percentage gels. A typical horizontal system is the Multiphor II system that analyzes one gel at a time, using a precast gradient gel (180×245×0.5 mm), and a typical vertical system is the Dodeca system, which analyzes up to 12 gels at a time, using usually a single‐concentration gel (190×205×1 mm). The present study evaluated the spatial and quantitative reproducibility of the two systems for the separation of the complex human pituitary proteome. PDQuest software was used to analyze the digitized gel‐image data, and SPSS statistical software was used to analyze the data. The results demonstrated a high percentage (>99%) of protein‐spot matches within each electrophoretic system. The Dodeca gel system demonstrated better between‐gel reproducibility for spot position, higher resolution in the Sodium dodecyl sulfate (SDS)‐PAGE direction, lower gel background, better spot quality, and higher reproducibility of the spot volume.
Profiling stage‐dependent changes of protein expression in Caenorhabditis elegans by mass spectrometric proteome analysis leads to the identification of stage‐specific marker proteins
Authors: Mádi András , Mikkat Stefan , Ringel Bruno , Thiesen Hans‐Jürgen , Glocker Michael O. 
Published: May 2003

AbstractProteome maps obtained by synchronization of the wild‐type Caenorhabditis elegans development reflected stage‐dependent molecular differences and revealed dynamic cytoskeletal processes during ontogenesis. Distinct protein spots that may function as molecular markers for the corresponding developmental stages were mass spectrometrically identified. The amount of the Cu2+– Zn2+ superoxide dismutase (CE23550) and an aspartyl proteinase (CE21681) was highest in the first larval stage (L1) and decreased during the ontogenesis from the first larval stage to the adult. Tropomyosin III (CE29059) was prominently present in the first and second larval stage (L1/L2). Abundances of actin 1 or 4 (CE12358 or CE13148) and tropomyosin I (CE28782) were particularly high in multiple spots in the third larval stage (L3). Interestingly, the amount of DIM‐1 protein (CE27706), reflected by two spots, was the lowest in this stage. A particular splicing factor (CE31089) was detected only in the fourth larval stage (L4), whereas a spot with high abundance representing the cuticle collagen (CE02272) was only found highly expressed in adult animals (A). In addition, a Ca2+‐binding protein (CE12368) and one protein spot which has not yet been identified, both reached their maximal spot intensities in the adult stage (A). Moreover, the ASP‐1, CCT‐5, GPD‐1, GPD‐2, HSP‐6, HSP‐16.2, IFB‐2, LEC‐2, LIN‐53, LMN‐1, MDH‐1, NUD‐1, RPA‐0, RSP‐12, SOD‐1, TBB‐1, TBB‐2, TMY‐1, UNC‐60, and VIT‐2 proteins for which mutants are available and two still unidentified protein spots which were present in all developmental stages, have been reproducibly localized in proteome maps of distinct ontogenesis states.
Vertical agarose gel electrophoresis and electroblotting of high‐molecular‐weight proteins
Authors: Warren Chad M. , Krzesinski Paul R. , Greaser Marion L. 
Published: May 2003

AbstractThe electrophoretic separation of high‐molecular‐weight proteins (> 500 kDa) using polyacrylamide is difficult because gels with a large enough pore size for adequate protein mobility are mechanically unstable. A 1% vertical sodium dodecyl sulfate (SDS)‐agarose gel electrophoresis (VAGE) system has been developed that allows titin (a protein with the largest known SDS subunit size of 3000–4000 kDa) to migrate over 10 cm in a ∼13 cm resolving gel. Such migration gives clear and reproducible separation of titin isoforms. Proteins ranging in size from myosin heavy chain (∼ 220 kDa) up to titin can be resolved on this gel system. Electroblotting of these very large proteins was nearly 100% efficient. This VAGE system has revealed two titin size variants in rabbit psoas muscle, two N2BA bands in rabbit cardiac muscle, and species differences between titins from rat and rabbit muscle. Agarose electrophoresis should be the method of choice for separation and blotting of proteins with very large subunit sizes.
Proteomic profiling of pancreatic ductal carcinoma cell lines treated with trichostatin‐A
Authors: Cecconi Daniela , Scarpa Aldo , Donadelli Massimo , Palmieri Marta , Hamdan Mahmoud , Astner Hubert , Righetti Pier Giorgio 
Published: May 2003

AbstractA pancreatic adenocarcinoma cell line (Paca44) was treated with trichostatin‐A (TSA), a potent inhibitor of histone deacetylases, in order to evaluate the effect of this drug on protein expression. Master maps of control and treated Paca44 cells were generated by analysis with the PDQuest software. The comparison between such maps showed up‐ and downregulation of 51 polypeptide chains, out of a total of 700 spots detected by a medium‐sensitivity stain, micellar Coomassie Brilliant Blue. Fingerprinting by matrix‐assisted laser desorption/ionization‐time of flight (MALDI‐TOF)‐mass spectrometry analysis enabled the identification of 22 of these spots. Among these proteins, of particular interest are the two downregulated proteins nucleophosmin and translationally controlled tumor protein, as well as the upregulated proteins programmed cell death protein 5 (also designated as TFAR19) and stathmin (oncoprotein 18). The modulation of these four proteins is consistent with our observation that TSA is able to inhibit cell growth of Paca44 by causing cell cycle arrest at the G2 phase and apoptotic cell death.
Testing the mixture‐of‐distributions hypothesis using “realized” volatility
Authors: Luu James C. , Martens Martin 
Published: May 2003

AbstractThe mixture‐of‐distributions hypothesis (MDH) posits that price volatility and
trading volume are both subordinated to the same information arrival rate or “news” process.
Existing studies that test MDH have the problem that both the information arrival rate and volatility are
unobservable. Recent work (e.g., Andersen et al., 2001) suggests that
intraday returns can be used to construct estimates of daily return volatility that are more precise than those
constructed using daily returns. In a way, realized volatility becomes observable. Conducting a number of tests
of MDH we find that every conclusion based on the daily squared return is reversed when using realized
volatility based on intraday returns. Hence, the mixed evidence on MDH in the existing literature can in part be
attributed to the use of poor realized volatility measures. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark
23:661–679, 2003
The interrelation of price volatility and trading volume of currency options
Authors: Sarwar Ghulam 
Published: May 2003

AbstractThis article examines the interrelations between future volatility of the U.S. dollar/British pound
exchange rate and trading volume of currency options for the British pound. The future volatility of the
exchange rate is approximated alternatively by implied volatility and by IGARCH volatility. The results suggest
the presence of strong contemporaneous positive feedbacks between the exchange rate volatility and the trading
volume of call and put options. Previous option volumes have significant predictive power with respect to the
expected future volatility of the dollar/pound exchange rate. Similarly, lagged volatilities jointly have
significant predictive power for option volume. Although option volume (volatility) responds somewhat
differently to individual volatility (volume) terms under the two volatility measures, the overall
volume‐volatility relations are broadly similar between the implied and IGARCH volatilities. The results
generally support the hypothesis that the information‐based trading explains more of the trading volume
in currency options on the U.S. dollar/British pound exchange rate than hedging. © 2003 Wiley
Periodicals, Inc. Jrl Fut Mark 23:681–700, 2003
Decreased price clustering in FTSE100 futures contracts following a transfer from floor to electronic trading
Authors: ap Gwilym Owain , Alibo Evamena 
Published: May 2003

AbstractThe issues of price clustering and electronic trading have triggered important recent debates, and generated
interest from regulators due to their potential implications for market quality, stability, and fairness. This
paper brings together these issues by examining whether price‐clustering behavior differs following a
transfer of futures contracts from open outcry trading to an electronic system. The results are unique in
demonstrating a structural change in price clustering following the move to automated trading, with the level of
price clustering dropping from around 98.5% of prices at even ticks under floor trading to approximately
75% under electronic trading. Such a change in pricing behavior amounts to a reduction in the effective
tick size, and is an important factor in reducing observed bid‐ask spreads. © 2003 Wiley
Periodicals, Inc. Jrl Fut Mark 23:647–659, 2003
Futures market equilibrium under Knightian uncertainty
Authors: Lien Donald , Wang Yaqin 
Published: May 2003

AbstractThis paper examines the effects of Knightian uncertainty on a commodity futures market within the
Newbery‐Stiglitz framework. It is shown that Knightian traders act more conservatively. In a partial
trade equilibrium, risk aversion and Knightian uncertainty have qualitatively similar effects on the equilibrium
price and the equilibrium trading volume. Full‐trade and no‐trade equilibria are likely to prevail
when the producer and the speculator incur different Knightian uncertainty. Herein different impacts of risk
aversion and Knightian uncertainty are observed. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark
23:701–718, 2003
Stock return dynamics, option volume, and the information content of implied volatility
Authors: Mayhew Stewart , Stivers Chris 
Published: May 2003

AbstractThis article reports new empirical results on the information content of implied volatility, with respect to
modeling and forecasting the volatility of individual firm returns. The 50 firms with the highest option volume
on the Chicago Board Options Exchange between 1988 and 1995 are examined. First, the results indicate that the
ability of implied volatility to subsume all relevant information about conditional variance depends on option
trading volume. For the most active options in the sample, implied volatility reliably outperforms GARCH and
subsumes all information in return shocks beyond the first lag. For these active options, implied volatility
performs substantially better than indicated by the prior results of Lamoureux and Lastrapes (1993), despite significant methodological improvements in the time‐series
volatility models in this study including the use of high‐frequency intraday return shocks. For the lower
option‐volume firms in the sample, the performance of implied volatility deteriorates relative to
time‐series volatility models. Finally, compared to a time‐series approach, the implied volatility
of equity index options provides reliable incremental information about future firm‐level volatility.
© 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:615–646, 2003
Enhanced binding of nor‐binaltorphimine to κ‐opioid receptors in rats dependent on butorphanol
Authors: Fan Lir‐Wan , Tien Lu‐Tai , Tanaka Sachiko , Sasaki Kenro , Park Younjoo , Ma Tangeng , Rockhold Robin William , Ho Ing Kang 
Published: May 2003

AbstractAutoradiographic characterization of binding for brain κ1 ([3H]CI‐977) and κ2 ([3H]bremazocine) in the presence of DAMGO ([D‐Ala2,N‐Me‐Phe4,Gly5‐ol]‐enkephalin), DPDPE ([D‐Pen2, D‐Pen5]‐enkephalin), and U‐69,593 opioid receptors, in the presence of different concentrations of a selective unlabeled κ‐opioid receptor antagonist, nor‐binaltorphimine (nor‐BNI), was performed in rats in which dependence on or withdrawal from butorphanol had been established. Dependence was induced by a 72 hr intracerebroventricular (i.c.v.) infusion with butorphanol (26 nmol/μl/hr; butorphanol dependent). Butorphanol withdrawal was produced by terminating the infusion of butorphanol in dependent animals. Responses were studied 7 hr following termination (butorphanol withdrawal). IC50 values from competition studies were estimated by fitting inhibition curves for both κ1‐ and κ2‐opioid receptor assays. In both dependent and withdrawal groups, the IC50 values obtained against [3H]CI‐977 or [3H]bremazocine with nor‐BNI were decreased (ratios of ∼0.03–0.21 and ∼0.05–0.42 vs. control, respectively) in brain regions, including frontal cortex, nucleus accumbens, claustrum, dorsal endopiriform nucleus, caudate putamen, parietal cortex, posterior basolateral amygdaloid nucleus, dorsomedial hypothalamus, hippocampus, posterior paraventricular thalamic nucleus, periaqueductal gray, substantia nigra, superficial gray layer of the superior colliculus, ventral tegmental area, and locus coeruleus, compared with control. These results indicate that, in butorphanol‐dependent and butorphanol‐withdrawal rats, the brain κ1‐ and κ2‐opioid receptors developed a supersensitivity to antagonist binding. © 2003 Wiley‐Liss, Inc.