bluuebunny/crossref_metadata_2025_split huggingface dataset:
Galactic X‐ray surveys
Authors: Ebisawa K. , Yamauchi S. , Bamba A. , Ueno M. , Senda A. 
Published: February 2003

AbstractWe review highlights of the results obtained from recent Galactic X‐ray survey observations, in particular ASCA Galactic center and plane surveys and our Chandra deep survey on the (l, b) ≈ (28°.5, 0°.0) region. Strong hard X‐ray diffuse components are observed from Galactic ridge, center and bulge, and they have both thermal and non‐thermal spectral components. Dozens of discrete and extended sources have been discovered on the Galactic plane, which also indicate thermal and/or non‐thermal X‐ray energy spectra. They are often associated with radio sources and are considered to be SNR candidates. Most of the hard X‐ray point sources in the outer part of the Galactic plane are considered to be background AGNs, while fraction of the Galactic hard X‐ray sources (such as quiescent dwarf novae) increases toward the Galactic center. Most of the soft X‐ray sources on the Galactic plane are presumably nearby active stars.
The XMM‐Newton serendipitous source catalogue
Authors: Watson M.G. , Pye J.P. , Denby M. , Osborne J.P. , Barret D. , Boller Th. , Brunner H. , Ceballos M.T. , Dellaceca R. , Fyfe D.J. , Lamer G. , Maccacaro T. , Michel L. , Motch C. , Pietsch W. , Saxton R.D. , Schröder A.C. , Stewart I.M. , Tedds J.A. , Webb N. 
Published: February 2003

AbstractWe describe the production, properties and scientific potential of the XMM‐Newton catalogue of serendipitous X‐ray sources. The first version of this catalogue is nearing completion and is planned to be released in early 2003.
Do sub‐mm sources and quasars form an evolutionary sequence?
Authors: Almaini O. 
Published: February 2003

AbstractThe high redshift sub‐mm sources discovered by SCUBA are widely believed to represent the dust‐enshrouded formation of massive elliptical galaxies. Given the strong evidence for a link between the formation of the spheroid and the growth of the central black hole, one might expect to see a luminous quasar at the nucleus of every SCUBA source. Somewhat surprisingly, however, only a very small fraction (∼ 5%) are detected in X‐rays. In this paper I discuss some of the implications of these results and discuss the accumulating evidence that sub‐mm sources and quasars may represent different stages in the evolutionary sequence of a massive proto‐spheroid.
ROSITA
Authors: Predehl P. , Friedrich P. , Hasinger G. , Pietsch W. 
Published: February 2003

AbstractThe Max‐Planck‐Institut für extraterrestrische Physik, the Astrophysikalisches Institut Potsdam, and the Institut für Astronomie und Astrophysik of the university of Tübingen, together with European cooperation partners and ESA, plan to install an X‐ray telescope on the International Space Station (ISS). The mission ROSITA (ROentgen Survey with an Imaging Telescope Array) will perform the first imaging all‐sky survey in the medium energy X‐ray range up to 10 keV with an unprecedented spectral and angular resolution. The main scientific goals are (1) to detect systematically all obscured accreting Black Holes in nearby galaxies and altogether about 50,000 AGN in the 2‐10 keV band, (2) to detect the hot intergalactic medium of several ten thousand galaxy clusters, and (3) to study in detail the physics of galactic X‐ray source populations, like pre‐main sequence stars, supernova remnants, and X‐ray binaries. In the hard X‐ray band (above 2 keV) the ROSITA survey will have a hundred times higher sensitivity and a hundred times better angular resolution than the last all‐sky survey in this band, which was performed about 25 years ago. In the soft band (0.5‐2 keV) the ROSITA survey will be more sensitive and have a substantially better energy and also angular resolution than the ROSAT all‐sky survey. The telescope will consist of seven 27‐fold nested Wolter‐1 mirror systems, the type already flown on ABRIXAS, and a novel detector system currently being developed by MPE on the basis of the successful XMM pn‐CCD technology. Major improvements of the new camera are a higher time and energy resolution.
DUET – The Dark Universe Exploration Telescope
Authors: Jahoda K. 
Published: February 2003

AbstractDUET, a proposed NASA Midex class mission, will produce a catalog of ∼ 20,000 X‐ray selected clusters and groups of galaxies suitable for detailed cosmological investigations. We present the cosmological constraints achievable by DUET, the functional requirements of the survey, and briefly describe an instrument/mission design capable of achieving these requirements. The advantages of an X‐ray survey for constraining the nature and amount of dark energy and dark matter are emphasized. Constraints on cosmological parameters are precise and complementary to other approaches. The density of dark energy, dark matter, and neutrinos will be measured with a statistical uncertainty of 0.5%, 0.5%, and 0.2% of the critical density and the dark energy equation of state can be measured to ±0.2 if dark energy and dark matter contribute ∼2/3 and ∼1/3 of the critical density as currently believed. DUET is a multi‐national collaboration led by GSFC with substantial contributions from groups in the US, Europe, and Japan.
Flow cytometric detection of β‐D‐glucuronidase gene in wild‐type bacterial cells using in‐situ PCR
Authors: Sachidanandham Ramaiah , Gin Karina Yew‐Hoong 
Published: February 2003

AbstractAn in situ PCR‐based flow cytometry method useful for monitoring the presence or absence of the β‐D‐glucuronidase gene in Escherichia coli has been developed. A single‐step fixation and permeabilization procedure, which maintained cell integrity at the elevated temperatures used during thermal cycling in the presence of PCR reagents, was demonstrated. We have chosen a shorter DNA sequence of length 147 bp for the PCR. Cells subjected to in situ PCR using fluorescein‐12‐dUTP as a label, showed the presence of uid both in epifluorescence microscopic examination and flow cytometric analysis. Multi‐parametric analysis of flow cytometric profiles revealed that the efficiency of labeling was found to be high. The potential of in situ PCR for the detection of uid in intact coliform cells was then successfully tested with a fecal coliform isolated from the coastal waters of Singapore. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 127–133, 2003.
Free intracellular amino acid pools during autonomous oscillations in Saccharomyces cerevisiae
Authors: Hans Michael A. , Heinzle Elmar , Wittmann Christoph 
Published: February 2003

AbstractIn the present work dynamic changes of free intracellular amino acid pools during autonomous oscillations of Saccharomyces cerevisiae were quantified in glucose‐limited continuous cultivations. At a dilution rate of D = 0.22 h−1 cyclic changes with a period of 120 min were found for many variables such as carbon dioxide production rate, dissolved oxygen, pH, biomass content, and various metabolite concentrations. On the basis of the observed dynamic patterns, free intracellular amino acids were classified to show oscillatory, stationary, or chaotic behavior. Amino acid pools such as serine, alanine, valine, leucine, or lysine were subjected to clear oscillations with a frequency of 120 min, identical to that of other described cultivation variables, indicating that there is a direct correlation between the periodic changes of amino acid concentrations and the metabolic oscillations on the cellular level. The oscillations of these amino acids were unequally phase‐delayed and had different amplitudes of oscillation. Accordingly, they exhibited different patterns in phase plane plots vs. intracellular trehalose. Despite the complex and marked metabolic changes during oscillation, selected intracellular amino acids such as histidine, threonine, isoleucine, or arginine remained about constant. Concentrations of glutamate and glutamine showed a chaotic behavior. However, the ratio of glutamate to glutamine concentration was found to be oscillatory, with a period of 60 min and a corresponding figure eight‐shaped pattern in a plot vs. trehalose concentration. Considering the described diversity, it can be concluded that the observed periodic changes are neither just the consequence of low or high rates of protein biosynthesis/degradation nor correlated to changing cell volumes during oscillation. The ratio between doubling time (189 min) and period of oscillation of intracellular amino acids (120 min) was 1:6. The fact that there is a close relationship between doubling time and period of oscillation underlines that the described autonomous oscillations are cell‐cycle‐associated. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 143–151, 2003.
Metabolic analysis of the synthesis of high levels of intracellular human SOD in Saccharomyces cerevisiae rhSOD 2060 411 SGA122
Authors: Gonzalez Ramon , Andrews Barbara A. , Molitor Julia , Asenjo Juan A. 
Published: February 2003

AbstractThe synthesis of human superoxide dismutase (SOD) in batch cultures of a Saccharomyces cerevisiae strain using a glucose‐limited minimal medium was studied through metabolic flux analysis. A stoichiometric model was built, which included 78 reactions, according to metabolic pathways operative in these strains during respirofermentative and oxidative metabolism. It allowed calculation of the distribution of metabolic fluxes during diauxic growth on glucose and ethanol. Fermentation profiles and metabolic fluxes were analyzed at different phases of diauxic growth for the recombinant strain (P+) and for its wild type (P−). The synthesis of SOD by the strain P+ resulted in a decrease in specific growth rate of 34 and 54% (growth on glucose and ethanol respectively) in comparison to the wild type. Both strains exhibited similar flux of glucose consumption and ethanol synthesis but important differences in carbon distribution with biomass/substrate yields and ATP production 50% higher in P−. A higher contribution of fermentative metabolism, with 64% of the energy produced at the phosphorylation level, was observed during SOD production. The flux of precursors to amino acids and nucleotides was higher in the recombinant strain, in agreement with the higher total RNA and protein levels. Lower specific growth rates in strain P+ appear to be related to the decrease in the rate of synthesis of nonrecombinant protein, as well as a decrease in the activities of the pentose phosphate (PP) pathway and TCA cycle. A very different way of entry into the stationary phase was observed for each strain: in the wild‐type strain most metabolic fluxes decreased and fluxes related to energy reserve synthesis increased, while in the P+ strain the flux of 22 reactions (including PP pathway and amino acids biosynthesis) related to SOD production increased their fluxes. Changes in SOD production rates at different physiological states appear to be related to the differences in building blocks availability between respirofermentative and oxidative metabolism. Using the present expression system, ideal conditions for SOD synthesis are represented by either active growth during respirofermentative metabolism or transition from a growing to a nongrowing state. An increase in SOD flux could be achieved using an expression system nonassociated to growth and potentially eliminating part of the metabolic burden. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 152–169, 2003.
Compression of biocompatible liquid‐filled HSA‐alginate capsules: Determination of the membrane mechanical properties
Authors: Carin Muriel , Barthès‐Biesel Dominique , Edwards‐Lévy Florence , Postel Caroline , Andrei Diana Cristina 
Published: February 2003

AbstractCompression experiments between two parallel plates are performed on a series of biocompatible HSA‐alginate capsules with two different membrane thicknesses. The capsule geometry and size as well as the average membrane thickness are first measured. The compression set‐up is fitted with a sensitive force transducer that allows measurement of the compression force as a function of plate separation. The response of the capsule is analyzed by assuming different constitutive models for the membrane, where the shear and surface dilatation effects are accounted. An apparent area dilatation modulus is then computed for different values of the plate separation and required to remain constant as the capsule deformation increases. This allows identification of plausible constitutive laws for the membrane material. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 207–212, 2003.
Self‐assembly of Pseudomonas fluorescens lipase into bimolecular aggregates dramatically affects functional properties
Authors: Fernández‐Lorente Gloria , Palomo José M. , Fuentes Manuel , Mateo Cesar , Guisán José M. , Fernández‐Lafuente Roberto 
Published: February 2003

AbstractIt has been found that lipase from Pseudomonas fluorescens (PFL) is able to aggregate into bimolecular structures (MW around 66 kD) even at moderate enzyme concentrations. At very low enzyme concentrations and in the presence of detergents, the same enzyme displayed a unimolecular structure with a molecular weight of 33 kD. Both enzyme structures displayed different functional properties. First, the bimolecular structure was much more stable than the unimolecular species (the bimolecular structure maintained over 80% of initial activity after 72 hours at 45°C, while the unimolecular structure retained only around 30% of initial activity after 4 hours of incubation under the same experimental conditions); and the bimolecular form presented a higher optimal T. Second, the unimolecular form showed a much lower KM for ethyl butyrate than the bimolecular form. Third, the interfacial activation in biphasic substrate‐aqueous milieu was higher for the bimolecular form. Fourth, the unimolecular structure was less active but much more enantioselective than the unimolecular species in the model reaction used. It is proposed that the bimolecular aggregates of PFL might be formed by two open lipase molecules (mutual interfacial activation), in intimate contact, and that the bimolecular form represents an example of “pseudo‐quaternary” structure. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 232–237, 2003.
Oxidation of 4‐bromophenol by the recombinant fused protein cellulose‐binding domain‐horseradish peroxidase immobilized on cellulose
Authors: Levy Ilan , Ward Gary , Hadar Yitzhak , Shoseyov Oded , Dosoretz Carlos G. 
Published: February 2003

AbstractA fused protein consisting of cellulose‐binding domain (CBD) and horseradish peroxidase (HRP) was constructed and expressed in Escherichia coli. Refolded recombinant CBD‐HRP (95% recovery yield) was bound to microcrystalline cellulose and applied for the oxidation of a model toxic phenol, 4‐bromophenol (BP). Oxidation of BP by CBD‐HRP resulted in the formation of dimers to pentamers as evidenced by mass spectrometry analysis. When immobilized, the vast majority of the oxidation products adsorbed to the cellulose matrix. CBD‐HRP (0.75 pyrogallol units) bound to 0.1 g cellulose was packed in a column, connected to an HPLC pump and monitoring system, and column performance and capacity were studied under various operating conditions. When performance was studied as a function of BP loading rate at a constant H2O2 loading rate of 1500 nmol/min, Vappmax and Kmapp were calculated to be 5.29 ± 0.46 μmol mL min and 644.9 ± 114.3 μM, respectively. Immobilized CBD‐HRP exhibited enhanced stability to H2O2 and oxidized considerably more BP than free CBD‐HRP. Inclusion of gelatin, which suppresses product‐dependent inactivation, further increased the amount of BP oxidation. These findings may have potential impact in terms of enzyme supply in high‐rate treatment of wastewater contaminated with toxic phenols, since the susceptibility of peroxidases to both H2O2 ‐ and product‐dependent inactivation demands continuous supply of fresh enzyme. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 223–231, 2003.
Proteome analysis of the plasma membrane of Mycobacterium tuberculosis
Authors: Sinha Sudhir , Arora Shalini , Kosalai K. , Namane Abdelkader , Pym Alex S. , Cole Stewart T. 
Published: February 2003

AbstractThe plasma membrane of Mycobacterium tuberculosis is likely to contain proteins that could serve as novel drug targets, diagnostic probes or even components of a vaccine against tuberculosis. With this in mind, we have undertaken proteome analysis of the membrane of M. tuberculosis H37Rv. Isolated membrane vesicles were extracted with either a detergent (Triton X114) or an alkaline buffer (carbonate) following two of the protocols recommended for membrane protein enrichment. Proteins were resolved by 2D‐GE using immobilized pH gradient (IPG) strips, and identified by peptide mass mapping utilizing the M. tuberculosis genome database. The two extraction procedures yielded patterns with minimal overlap. Only two proteins, both HSPs, showed a common presence. MALDI–MS analysis of 61 spots led to the identification of 32 proteins, 17 of which were new to the M. tuberculosis proteome database. We classified 19 of the identified proteins as ‘membrane‐associated’; 14 of these were further classified as ‘membrane‐bound’, three of which were lipoproteins. The remaining proteins included four heat‐shock proteins and several enzymes involved in energy or lipid metabolism. Extraction with Triton X114 was found to be more effective than carbonate for detecting ‘putative’ M. tuberculosis membrane proteins. The protocol was also found to be suitable for comparing BCG and M. tuberculosis membranes, identifying ESAT‐6 as being expressed selectively in M. tuberculosis. While this study demonstrates for the first time some of the membrane proteins of M. tuberculosis, it also underscores the problems associated with proteomic analysis of a complex membrane such as that of a mycobacterium. Copyright © 2002 John Wiley & Sons, Ltd.
Heterologous expression and purification systems for structural proteomics of mammalian membrane proteins
Authors: Mus‐Veteau Isabelle 
Published: February 2003

AbstractMembrane proteins (MPs) are responsible for the interface between the exterior and the interior of the cell. These proteins are implicated in numerous diseases, such as cancer, cystic fibrosis, epilepsy, hyperinsulinism, heart failure, hypertension and Alzheimer's disease. However, studies on these disorders are hampered by a lack of structural information about the proteins involved. Structural analysis requires large quantities of pure and active proteins. The majority of medically and pharmaceutically relevant MPs are present in tissues at very low concentration, which makes heterologous expression in large‐scale production‐adapted cells a prerequisite for structural studies. Obtaining mammalian MP structural data depends on the development of methods that allow the production of large quantities of MPs. This review focuses on the different heterologous expression systems, and the purification strategies, used to produce large amounts of pure mammalian MPs for structural proteomics. Copyright © 2002 John Wiley & Sons, Ltd.
SMAD7 is a prognostic marker in patients with colorectal cancer
Authors: Boulay Jean‐Louis , Mild Gabriele , Lowy Adam , Reuter Juergen , Lagrange Magali , Terracciano Luigi , Laffer Urban , Herrmann Richard , Rochlitz Christoph 
Published: February 2003

AbstractChromosomal region 18q21 is frequently deleted in colorectal cancer (CRC) and is associated with poor prognosis. Potential tumor suppressor mechanisms altered by 18q21 deletion include mediation of TGFβ signaling by SMADs. Following the definition of SMAD4 deletion as a negative predictive marker for chemotherapy benefit in patients with CRC, we aimed to evaluate the clinical relevance of the deletion of other SMAD genes clustered in this region: SMAD2 and SMAD7 in 264 CRC biopsies from a previous clinical study. In contrast to SMAD2 deletion, for which no clinical relevance was observed, hazard ratios (HR) in a multivariate analysis associated with SMAD7 deletion [overall survival (OS): HR = 0.43, p = 0.0012; disease‐free survival (DFS): HR = 0.50, p = 0.0033] indicated a favorable outcome for these patients. In addition, SMAD7 duplication had a hazardous effect on survival [OS: HR = 2.10, p = 0.020; DFS: HR = 2.06, p = 0.015]. Moreover, the HRs associated with one additional copy of SMAD7 were 1.76, p = 0.00024 [OS] and 1.64, p = 0.00048 [DFS] respectively, showing a graded effect of SMAD7 on patient outcome depending on gene copy number that suggests a dose‐and‐effect basis. Since SMAD7 blocks TGFβ signaling, these data are consistent with the loss of SMAD7 rendering carcinoma cells more sensitive to cell growth arrest/apoptotic effect of TGFβ, whereas gain of SMAD7 function might result in TGFβ resistance, thereby emphasizing the role of TGFβ in tumor suppression. © 2003 Wiley‐Liss, Inc.
Optimal excitation‐emission wavelengths for autofluorescence diagnosis of bladder tumors
Authors: Zheng Wei , Lau Weber , Cheng Christopher , Soo Khee Chee , Olivo Malini 
Published: February 2003

AbstractTissue autofluorescence depends on endogenous fluorophores in the tissue, which undergo a change associated with malignant transformation. This change can be detected as an alteration in the spectral profile and intensity of autofluorescence. Our purpose was to determine the optimal excitation and emission wavelengths for autofluorescence diagnosis of bladder cancer. A total of 52 bladder tissue specimens were obtained from 25 patients undergoing mucosal biopsies or surgical resections of bladder tumors. Light‐induced autofluorescence measurements were performed to study the spectroscopic differences between normal and malignant bladder tissue. Fluorescence excitation wavelengths varying from 220 to 500 nm were used to induce tissue autofluorescence, and emission spectra were measured in the 280–700 nm range. These spectra were then combined to construct 2‐dimensional fluorescence excitation‐emission matrices (EEMs). Significant changes in fluorescence intensity of EEMs were observed between normal and tumor bladder tissues, the most marked differences being at the excitation wavelengths of 280 and 330 nm. The diagnostic algorithm based on the combination of the fluorescence peak intensity ratios of I350/I470 at 280 nm excitation and I390/I470 at 330 nm excitation yielded a sensitivity of 100% [95% confidence interval (CI) 0.95–1.0] and specificity of 100% (95% CI 0.90–1.0). The results of the present fluorescence EEM study demonstrate that autofluorescence spectroscopy can distinguish malignant from normal bladder tissue and that excitation wavelengths of 280 and 330 nm are the most significant for differentiation between normal and malignant bladder mucosae with a high degree of diagnostic accuracy. © 2003 Wiley‐Liss, Inc.