bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal Structures of
Escherichia coli
Topoisomerase IV ParE Subunit (24 and 43 Kilodaltons): a Single Residue Dictates Differences in Novobiocin Potency against Topoisomerase IV and DNA Gyrase
Authors: Bellon Steven , Parsons Jonathan D. , Wei Yunyi , Hayakawa Koto , Swenson Lora L. , Charifson Paul S. , Lippke Judith A. , Aldape Robert , Gross Christian H. 
Published: April 2004

ABSTRACT

Topoisomerase IV and DNA gyrase are related bacterial type II topoisomerases that utilize the free energy from ATP hydrolysis to catalyze topological changes in the bacterial genome. The essential function of DNA gyrase is the introduction of negative DNA supercoils into the genome, whereas the essential function of topoisomerase IV is to decatenate daughter chromosomes following replication. Here, we report the crystal structures of a 43-kDa N-terminal fragment of
Escherichia coli
topoisomerase IV ParE subunit complexed with adenylyl-imidodiphosphate at 2.0-Å resolution and a 24-kDa N-terminal fragment of the ParE subunit complexed with novobiocin at 2.1-Å resolution. The solved ParE structures are strikingly similar to the known gyrase B (GyrB) subunit structures. We also identified single-position equivalent amino acid residues in ParE (M74) and in GyrB (I78) that, when exchanged, increased the potency of novobiocin against topoisomerase IV by nearly 20-fold (to 12 nM). The corresponding exchange in gyrase (I78 M) yielded a 20-fold decrease in the potency of novobiocin (to 1.0 μM). These data offer an explanation for the observation that novobiocin is significantly less potent against topoisomerase IV than against DNA gyrase. Additionally, the enzyme kinetic parameters were affected. In gyrase, the ATP

K
m

increased ≈5-fold and the
V
max
decreased ≈30%. In contrast, the topoisomerase IV ATP

K
m

decreased by a factor of 6, and the
V
max
increased ≈2-fold from the wild-type values. These data demonstrate that the ParE M74 and GyrB I78 side chains impart opposite effects on the enzyme's substrate affinity and catalytic efficiency.
Disposition and Metabolic Profiles of [
14
C]Viramidine and [
14
C]Ribavirin in Rat and Monkey Red Blood Cells and Liver
Authors: Lin Chin-Chung , Lourenco David , Xu Guifen , Yeh Li-Tain 
Published: April 2004

ABSTRACT

The disposition and metabolic profiles of [
14
C]viramidine and [
14
C]ribavirin were compared in rat and monkey red blood cells and liver. Our data reveal that the total ribavirin-related components (ribavirin plus its mono-, di-, and triphosphate metabolites) may account for most of the drug in monkey liver following prolonged oral administration of viramidine.
In Vitro Activity of a Novel Diaminopyrimidine Compound, Iclaprim, against
Chlamydia trachomatis
and
C. pneumoniae
Authors: Kohlhoff S. A. , Roblin P. M. , Reznik T. , Hawser S. , Islam K. , Hammerschlag M. R. 
Published: April 2004

ABSTRACT

The in vitro activities of iclaprim, a novel dihydrofolate reductase inhibitor, azithromycin, and levofloxacin were tested against 10 strains of
Chlamydia trachomatis
and 10 isolates of
Chlamydia pneumoniae
. For
C. trachomatis
and
C. pneumoniae
, the iclaprim MIC and minimal bactericidal concentration at which 90% of isolates were inhibited (MIC
90
and MBC
90
) were 0.5 μg/ml, compared to an azithromycin MIC
90
and MBC
90
of 0.125 μg/ml and levofloxacin MIC
90
s and MBC
90
s of 1 μg/ml for
C. trachomatis
and 0.5 μg/ml for
C. pneumoniae
.
Inhibition of Human Immunodeficiency Virus Type 1 Tat-
trans
-Activation-Responsive Region Interaction by an Antiviral Quinolone Derivative
Authors: Richter Sara , Parolin Cristina , Gatto Barbara , Del Vecchio Claudia , Brocca-Cofano Egidio , Fravolini Arnaldo , Palù Giorgio , Palumbo Manlio 
Published: April 2004

ABSTRACT

WM5, a 6-aminoquinolone derivative, binds with high affinity to the bulge of the
trans
-activation-responsive region (TAR), whereas it displays low binding affinity for the loop and stem regions of TAR and for random RNA and DNA sequences. Furthermore, WM5 disrupts the natural protein-nucleic acid complex with a 50% inhibitory concentration in the low micromolar range in both in vitro and in vivo assays.
Negotiating the Clouds Around Statistics and "Q": a Rejoinder and Independent Analysis
Authors: Mattila Sharon Lea 
Published: April 2004

AbstractIn 1994, the author critiqued a 1971 statistical study of "Q" by Charles E. Carlston and Dennis Norlin. Their recent reply has necessitated both a further clarification of their study's most serious flaws and an independent statistical analysis using a method that avoids these flaws. Such an analysis demonstrates that Matthew and Luke do not preserve "Q" sayings any more faithfully than Markan sayings. This can still be interpreted in support of "Q" being a single written source, but it is important to recall that the degree of Matt-Luke verbatim agreement is much lower than Carlston & Norlin's figures imply.
Ebenmass Im Epheserbrief: Stichometrische Kompositionsanalyse
Authors: Lang Friedrich Gustav 
Published: April 2004

AbstractDer Epheserbrief hat eine ausgefeilte symmetrische Struktur. Mittlerer Hauptteil ist 4,1-16; inhaltlich überlappen sich darin Ekklesiologie und Ethik, die beiden Themen der Teile davor bzw. danach. Dem entspricht die formale Disposition, die hier erstmals konsequent stichometrisch analysiert wird. Als Maßzeile dient der 15-Silben-Stichos. Die Textabschnitte 1,1-3,21 und 4,17-6,24 haben genau denselben Zeilenumfang, ebenso die Hauptteile 1,3-2,10 und 2,11-3,21; die Teile 4,17-5,14 und 5,15-6,24 stehen exakt im Verhältnis 2:3. Jeweils sind Bausteine von 21, 13 oder 8 Stichoi verwendet. Die Symmetrie im Briefaufbau erinnert an Körperbau und Tempelbau, kaum zufällig, denn im Epheserbrief ist beides Bild für die Kirche.
Evidence-Based Guidelines in Laboratory Medicine: Principles and Methods
Authors: Oosterhuis Wytze P , Bruns David E , Watine Joseph , Sandberg Sverre , Horvath Andrea R 
Published: April 2004

AbstractBackground: Guidelines are commonly used tools for supporting medical decisions. Formulating evidence-based recommendations has become a leading principle in guideline development.Aim: This narrative review integrates the most recent methods of evidence-based guideline development and adapts those to the field of laboratory medicine.Summary: We present a 10-step process and a list of criteria for the development of laboratory guidelines. Laboratory guidelines should be outcome oriented, be developed by a multidisciplinary team, and begin with a clear statement of the clinical question(s) that the use of the test(s) is addressing. The clinical questions define the type of study designs that offer the best evidence to answer those questions. Guidelines should be based on the critical appraisal and systematic review of literature and explicitly state the strength of evidence supporting each recommendation. Pragmatic considerations dictate that priority is given to topics with the highest clinical or economic impact. Scientific evidence is necessary but insufficient for recommendations, as considered judgment is required about benefits, harms, costs, and local applicability of recommendations. Formal consensus methods are needed when the evidence base is lacking or controversial. Guidelines should be disseminated widely and their impact monitored regularly. Regular reviewing is needed because the lack of timely updates is a major cause of nonadherence to guidelines.Conclusions: Guidelines should be developed in a transparent process by a multidisciplinary team, with graded recommendations based on critically appraised scientific studies. Systematic, standardized, and explicit methodology, adapted to laboratory medicine, should be followed when developing recommendations involving the use of laboratory tests.
Solvent extraction and separation of thorium(IV) and uranium(VI) by an ether-amide type tripodand
Authors: Zhijun Guo , Weiguang Zhang , Yanning Niu , Minyu Tan 
Published: April 2004

Summary
1,1,1-tris(N,N-diisobutylcarbamoyl-methyleneoxymethyl)propane (L) has been prepared and characterized by using IR, 1H NMR and positive-ion FAB mass spectra. The extraction of Th4+ and UO2
2+ with L was studied as a function of concentration of free extractant in an organic phase and of picrate in an aqueous phase from a picrate-nitrate medium at 293±1K. It was found that the extractability of L for Th4+ is larger than that for UO2
2+. Both extraction % of Th4+ and UO2
2+ decreased with an increase in the concentration of HNO3. The mechanism of extraction of Th4+ with L was proposed. The composition of extracted species of L with Th4+ in the organic phase is ThL(Pic)2(NO3)2. The results of extraction of trace 234Th4+ with L from the picrate-nitrate medium containing UO2
2+ (the initial concentration of UO2
2+, C
0
UO₂²⁺=1.23×10-4mol/dm3 (M)) agreed well with those from the extraction of single component solutions. The tripodand is useful in separation of Th4+ and UO2
2+ from each other in picrate-nitrate media with a relatively high separation factor.
Extraction of rubidium and caesium from strongly alkaline media
Authors: Dozol J. F. , Asfari Z. , Arnaud-Neu Francoise , Vicens J. , Thuéry P. 
Published: April 2004

Summary
Huge amounts of alkaline liquid waste containing a high sodium salt concentration (and in some cases, a lesser potassium salt concentration) are contaminated by 137caesium. Selective removal of radioactive caesium ions, present in the waste at trace level, requires very selective extractants since the ratio of sodium over caesium exceeds 105. As expected, calix[4]arene-crown-6 is satisfactory for the extraction of caesium from liquid waste containing large amounts of sodium. The presence of potassium, which competes more than sodium with caesium, leads to a drastic caesium distribution coefficient decrease as the concentration of this competing cation increases. On the contrary, calix[4]arene and p-tert-butylcalix[4]arene, efficient extractants in high alkalinity media, display an exceptional selectivity for caesium over other alkaline cations, including rubidium. This selectivity of p-tert-butylcalix[4]arene, and to a lesser extent of calix[4]arene, allows caesium to be extracted from alkaline solutions containing large amounts of sodium and potassium.
Lack of association or linkage disequilibrium between schizophrenia and polymorphisms in the 5‐HT1Dα and 5‐HT1Dβ autoreceptor genes: Family‐based association study
Authors: Ambrósio Alda M. , Kennedy James L. , Macciardi Fabio , Coelho Isabel , Soares Maria J. , Oliveira Catarina R. , Pato Carlos N. 
Published: April 2004

AbstractGenetic factors play a major role in the etiology of schizophrenia and disturbances of serotonergic pathways have been implicated in this disorder. The aim of the present study was to examine genetic association between schizophrenia and polymorphisms in the 5‐HT1Dα (TaqI) and 5‐HT1Dβ (T261G and G861C) autoreceptor genes in ninety trios from Portugal. No association or linkage disequilibrium was obtained between schizophrenia and 5‐HT1Dα and 5‐HT1Dβ autoreceptor genes with both haplotype relative risk (HRR) and transmission disequilibrium test (TDT). Concerning 5‐HT1Dβ autoreceptor gene, also negative results was obtained in the analysis of the haplotypes with transmit. Thus, our data provide no support for the hypothesis that polymorphisms at 5‐HT1Dα (TaqI) and 5‐HT1Dβ (T261G and G861C) genes contributes to susceptibility to schizophrenia in the Portuguese population. © 2004 Wiley‐Liss, Inc.
Dye‐molecular‐imprinted polysiloxanes. II. Preparation, characterization, and recognition behavior
Authors: Gong Shu‐Ling , Yu Zhao‐Ju , Meng Ling‐Zhi , Hu Ling , He Yong‐Bing 
Published: April 2004

AbstractMicrosphere silica (AMS) was prepared by the sol–gel method and used for the synthesis of dye‐molecular‐imprinted polysiloxanes. These were prepared by the cohydrolysis and polycondensation of the AMS with functional organosilicone monomers (N‐phenylaminomethyl triethoxysilane, 3‐aminopropyl triethoxysilane, and 4‐aza‐6‐aminohexyl triethoxysilane) in the presence of a template molecule of disperse red (or disperse blue or water‐soluble dye) followed by the removal of the template molecule. The molecular‐imprinting and nonimprinting polysiloxanes were characterized by elemental analysis, diffuse‐reflectance Fourier transform infrared spectroscopy, and scanning electron microscopy. Their adsorption behavior toward the template molecule and nontemplate molecule was investigated. The molecular‐imprinting polysiloxane exhibited higher selective recognition properties toward the template molecule than the nonimprinting polysiloxane. In the experimental conditions, their adsorption isotherms were a good fit with the Langmuir model. The distribution coefficient value of water‐soluble‐dye‐imprinted polysiloxane was the highest among the three imprinting polysiloxanes under the experimental conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 637–643, 2004
Modification of a Fischer‐Tropsch wax by grafting with maleic anhydride
Authors: Novák I. , Krupa I. , Luyt A. S. 
Published: April 2004

AbstractThe polarity of a hard Fischer‐Tropsch paraffin wax was improved through grafting of maleic anhydride (MA) initiated by dibenzoyl peroxide (DBP), which is reflected by a significant increase in the polar component of the surface free energy. MA and DBP concentrations of 3 wt % each are sufficient for significant modification of the polarity of the wax. FTIR spectra confirm the presence of anhydride groups on the wax chains, while gel permeation chromatograms show the development of a low molecular weight peak, which may be indicative of wax degradation. The grafting of wax by MA decreases the specific enthalpy of melting, as determined through differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 662–668, 2004
Correlation of Density Pedestal Width and Neutral Penetration Length
Authors: Xu X. Q. , Nevins W. M. , Cohen R. H. , Rognlien T. D. , Umansky M. V. 
Published: April 2004

AbstractPedestal studies in DIII‐D and MAST find good correlation between the width of the H‐mode density barrier and the neutral penetration length [1, 2]. These results suggest that the width may be set by the combined effects of neutrals and plasma transport. This paper is a report on fluid simulations of boundary plasma using the BOUT code[3] with a neutral source added. Thus both neutral and plasma physics are treated. The plasma transport is self‐consistently driven by boundary turbulence due to the resistive X‐point mode, while neutrals are described by a simple analytic model. The plasma profiles are evolved on the same time scale as the turbulence for the given heat source from the core plasma and particle source from the neutrals. For prescribed neutral profiles, we find the formation of a density pedestal inside the separatrix in the L‐mode even though the calculated plasma diffusion coefficients are almost radially constant and without the formation of a temperature pedestal. These results support the hypothesis that particle fueling can provide the dominant control for the size of the H‐mode density barrier. The width of the density barrier decreases as the pedestal density increases which is also consistent with experimental data. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Instability Driven by Sheath Boundary Conditions and Limited to Divertor Legs
Authors: Ryutov D. D. , Cohen R. H. 
Published: April 2004

AbstractAn instability driven by electron temperature gradient in combination with sheath boundary condition at the divertor plate is considered. A mode localized between the divertor plate and the X point is found. The further propagation of the mode is terminated by a strong shear near the X point. “Heuristic” boundary condition at the control surface situated somewhat below the X point is suggested. The mode manifests a strong dependence on the radial tilt of the divertor plate, thereby providing some degree of control over the plasma transport in the divertor leg. Estimates of the diffusion coefficient show that it may reach the Bohm value. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Universality of Intermittent Convective Transport in the Scrape‐off Layer of Magnetically Confined Devices
Authors: Antar Ghassan Y. 
Published: April 2004

AbstractThis article describes briefly recent results on the universality of intermittent convective transport reported in the scrape‐off layer. We show that the statistical properties of turbulence are identical for four different magnetic fusion devices. The four devices are the PISCES linear plasma device, the Tore Supra tokamak with limiter configuration, the Alcator C‐MOD with divertor configuration and high magnetic field, and theMAST spherical tokamak where the walls are far from the last closed flux surface (LCFS). These four devices do not only have different magnetic configurations but also have four different probes designs. Nine different types of statistical analyses are used, here we present just a few. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homoclinic tangles, bifurcations and edge stochasticity in diverted tokamaks
Authors: Evans T. E. , Roeder R. K. W. , Carter J. A. , Rapoport B. I. 
Published: April 2004

AbstractThe boundary and pedestal region of a poloidally diverted tokamak is particularly susceptible to the onset of vacuum magnetic field stochasticity due to small non‐axisymmetric resonant perturbations. Recent calculations of the separatrix topology in diverted tokamaks, when subjected to small magnetic perturbations, show the existence of complex invariant manifold structures known as homoclinic tangles. These structures appear above a relatively low perturbation threshold that depends on certain equilibrium shape parameters. Homoclinic tangles represent a splitting of the unperturbed separatrix into stable and unstable invariant manifolds associated with each X‐point (hyperbolic point). The manifolds that make up homoclinic tangles set the boundaries that prescribe how stochastic field line trajectories are organized i.e., how field lines from the inner domain of the unperturbed separatrix mix and are transported to plasma facing surfaces such as divertor target plates and protruding baffle structures. Thus, the topology of these tangles determines which plasma facing components are most likely to interact with escaping magnetic field lines and the parallel heat and particle flux they carry. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A 1‐D diffusive transport model for the density and temperature of edge neutrals
Authors: Owen L. W. , Moiduszewski P. K. 
Published: April 2004

AbstractA one‐dimensional (1‐D) model of neutral transport in edge plasmas is shown to reproduce the results of Monte Carlo simulations for a variety of edge plasma profiles. The transport of hydrogenic atoms is assumed to be diffusive with a flux limit that depends on the neutral mean‐free path and gradients of plasma density and ion temperature. The steady‐state continuity equation and a simple first order equation for the energy transfer between ions and neutral atoms are solved for the neutral atom density and temperature along the normal to the recycling (source) surface. Based upon particle and energy reflection coefficients for carbon, recycling is simulated with fluxes of both energetic reflected atoms and desorbed molecules. Assuming convective transport with constant velocity, the continuity equation for molecules is solved for the molecular density, which is shown to agree with Monte Carlo if flux enhancement due to backscattered atoms is included. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Expression analysis of the Drosophila pipsqueak family members fernández/distal antenna and hernández/distal antenna related
Authors: Suzanne Magali 
Published: April 2004

AbstractThe “pipsqueak” family is composed of proteins that contain a pipsqueak motif, a previously characterised DNA binding domain, and thus represents a new family of potential transcription factors. Previous functional characterisation of several Drosophila genes encoding pipsqueak domain‐containing proteins has shown their crucial role in development. Here, I report the embryonic, larval, and pupal expression pattern of two Drosophila genes, fernández/distal antenna and hernández/distal antenna related, which encode protein members of the pipsqueak family with similar pipsqueak motifs. Furthermore, I show that, consistently with their expression pattern, these two genes are required in the nervous system during the embryonic development. Developmental Dynamics 230:361–365, 2004. © 2004 Wiley‐Liss, Inc.
Adding value to vegetable waste: Oil press cakes as substrates for microbial decalactone production
Authors: Laufenberg Günther , Rosato Pietro , Kunz Benno 
Published: April 2004

AbstractIn this study several oil press cakes were investigated as exclusive substrates for different moulds and yeasts for the production of flavor‐active decalactones via solid‐state fermentation (SSF). Experiments are focused on pre‐treatment methods for olive cake to remove antimicrobial phenolic substances contained in the oil cake disturbing or even inhibiting microbial growth. Choosing Ceratocystis moniliformis as the reference microorganism best results were obtained by a combination of hot water flushes and enzymatic treatment of the cake. Fermentation with sunflower, olive and linseed cake did not lead to lactone formation in detectable amounts although all of these substrates provided good microbial growth. On castor cake, however, five microorganisms have synthesized the requested decalactones via SSF. Thus fermentation of the fungus Moniliella suaveolens on this substrate resulted in a maximum concentration of γ‐decalactone of 180.7 mg·kg−1 dry matter without optimization. Another δ‐lactone, 6‐pentyl‐α‐pyrone, was produced in small amounts by the fungus Trichoderma harzianum on castor cake.
Carbon monoxide and oxidative stress inDesulfovibrio desulfuricansB‐1388
Authors: Davydova M. , Sabirova R. , Vylegzhanina N. , Tarasova N. 
Published: April 2004

AbstractIt has been shown that carbon monoxide (CO) in low concentration may be an active biochemical and physiological regulator of cell function. The bases of CO toxicity and cell protection are not clearly understood. To provide insights into these mechanisms, we measured superoxide production byD. desulfuricansB‐1388 incubated anaerobically in Postgate medium with or without 5% CO.D. desulfuricansB‐1388 growing with CO in the gas phase produced more superoxide radicals then control cells growing in Ar. When the cells were pregrown with CO, NADH oxidase and peroxidase activities were increased. The increase in peroxidase activities of cells growing under CO (particularly NADH peroxidase) suggested that H2O2was accumulated in cells. Superoxide dismutase (SOD) activity of cells decreased in exponential growth phase and increased in stationary phase. This may be due to CO concentration fall during CO oxidation by CO dehydrogenase. Altogether, our data suggest that superoxide production is a possible mechanism of CO toxicity. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:87–91, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20011