julilili42/papers huggingface dataset:
[Ca2+]i‐ and insulin‐stimulating effect of the non‐membranepermeable phosphatase‐inhibitor microcystin‐LR in intact insulin‐secreting cells (RINm5F)
2000-07-01

Microcystin‐LR, a specific and effective inhibitor of serine/threonine phosphatases type 1/2A which does not permeate cells, was used to distinguish intracellular and extracellular effects of phosphatase inhibitors on insulin secretion by RINm5F cells. Incubation of intact RINm5F cells with microcystin‐LR (0.1–2 μ M ) almost doubled basal insulin release at 3 m M glucose but left maximal insulin release induced by KCl (30 m M ) unaffected. In parallel, there was an increase in cytosolic Ca 2+ by up to half maximum, which could be suppressed by the Ca 2+ ‐channel blocker D600. In contrast, microcystin‐LR incubation of intact cells did not affect phosphatase activity but significantly reduced phosphatase activity when used in cellular fractions. From these data we conclude that microcystin‐LR could affect Ca 2+ ‐channels and insulin release by inhibiting an extracellular phosphatase‐like activity. British Journal of Pharmacology (2000) 130 , 1406–1410; doi: 10.1038/sj.bjp.0703441
Synthesis of Nickel Phthalocyanines with One Aldehyde Group and Preparation of a Bisvinylene-Phenylene-Bridged Bisphthalocyanine
2000-07-01

The synthesis and characterization of two soluble, unsymmetrical nickel phthalocyanines with one aldehyde group in the α- (10b) and β-position (10a), respectively, is reported. The β-functionalized phthalocyanine (Pc) (10a) was used in a Wittig reaction to afford the first "real" bisvinylene-phenylene-bridged bisphthalocyanine 11. The properties of the new Pcs are compared with those of the corresponding tribenzonaphthoporphyrazino (TBNP) nickel analogues 1 and 3.
Magnetic Resonance Osteodensitometry in Human Heel Bones
2000-07-01

Spatial resolution in 3D GEI clearly influences the T2*-related signal characteristics. Despite measuring different physical properties of spongy bone by GEI and QCT, a relatively high correlation between GEI with small pixel sizes and QCT was obtained in the dorsal part of the heel bones, but not in the ventral part with partly thickened trabeculae and irregular distribution. However, standardized measuring protocols with preferably small pixel sizes (as low as [0.6 mm]3) should be applied, and correlation curves must be determined, dependent on the actual bone marrow site, before clinical routine MR osteodensitometry becomes possible.
Test of physics beyond the standard model in nuclei
2000-07-01

The modern theories of Grand Unification (GUT) and supersymmetric (SUSY) extensions of standard model (SM) suppose that the conservation laws of the SM may be violated to some small degree. The nuclei are well-suited as a laboratory to test fundamental symmetries and fundamental interactions like lepton flavor (LF) and lepton number (LN) conservation. A prominent role between experiments looking for LF and total LN violation play yet not observed processes of neutrinoless double beta decay. The GUT's and SUSY models offer a variety of mechanisms which allow this process to occur. They are based on mixing of Majorana neutrinos and/or R-parity violation hypothesis. Although the neutrinoless double beta decay has not been seen it is possible to extract from the lower limits of the lifetime upper limits for the effective electron Majorana neutrino mass, effective right handed weak interaction parameters, the effective Majoron coupling constant, R-parity violating SUSY parameters etc. In this work the limits on the LN violating parameters extracted from current neutrinoless double beta decay experiments are listed. Studies in respect to future neutrinoless double beta decay experimental projects are also presented.
Application of High-Resolution-Magic-Angle-Spinning (HR-MAS) NMR Spectroscopy to Cosmetic Emulsions
2000-07-01

Abstract HR-MAS NMR spectroscopy was utilized for the characterization of three cosmetic emulsions. The emulsions had the same chemical composition and were prepared in the same way except the homogenization step. Magic angle spinning (M A S) of the emulsions was applied to improve signal resolution by eliminating susceptibility changes as well as residual dipolar interactions within the sample. Spin-lattice relaxation times (T 1 ) were determined according to the inversion recovery technique in the temperature range of -10 °C to 40 °C to find out phase changes of the sample ingredients. 1 H and 13 C NMR signals of the individual components were assigned by use of different 1D and 2D NMR experiments. The HR-MAS NMR technique offers many possibilities to further investigate samples between the liquid and the solid state.
Water-soluble polymer-metal complexes for liquid-phase retention separation
2000-07-01

The concept and the major features of the Liquid-Phase Polymer-Based Retention (LPR) separation are outlined. The fundamentals of the metal ion interaction with respect to enrichment and separation procedures are developed and the role of complex-forming polymeric agents is discussed. The scope, major advancements, and typical application examples based on metal complexes are highlighted.
The southern Menderes Massif (western Turkey): geochronology and exhumation history
2000-07-01

In the southern flank of the Menderes Massif, western Turkey, an E–W-trending quartz–mica vein was recognized in the augen gneisses of the so-called 'core' series. Rb-Sr determinations of two undeformed or slightly deformed mica books from the vein yielded Palaeocene–Early Eocene ages (c. 62–43 Ma) for the vein formation. The new data are interpreted to closely post-date the time of major Barrovian-type High Temperature/Medium Pressure (HT/MP) main Menderes metamorphism (MMM) and coeval crustal-scale top-to-the-N-NNE Tertiary deformation that affected the whole Massif. Subsequent cooling occurred in the Middle Eocene (36 ± 2 Ma Ar-Ar mica ages). Top-to-the-N-NNE structures were later overprinted by top-to-the-S-SSW fabrics within normal-sense ductile shear zone, located between the core augen gneisses in the footwall and the structurally overlying cover schists in the hanging wall. The Massif was at the surface by the Early Miocene. Field relations clearly demonstrate that the age of top-to-the-S-SSW deformation is well constrained between the age of the MMM and the Early Miocene, and that exhumation was mainly tectonically controlled. Copyright © 2000 John Wiley & Sons, Ltd.
Improved sensitivity proteomics by postharvest alkylation and radioactive labeling of proteins
2000-07-01

We describe approaches to improve the detection of proteins by postharvest alkylation and subsequent radioactive labeling with either [3H]iodoacetamide or 125I. Database protein sequence analysis suggested that cysteine is not suitable for detection of the entire proteome, but that cysteine alkylating reagents can increase the number of proteins able to be detected by iodination chemistry. Proteins were alkylated with β-(4-hydroxyphenyl)ethyl iodoacetamide, or with 1,5-l-AEDANS (the Hudson Weber reagent). Subsequent iodination using the Iodo-Gen system was found to be most efficient. The enhanced sensitivity obtainable by using these approaches is expected to be sufficient for visualization of the lowest copy number proteins from human cells, such as from clinical samples. However, we argue that significantly improved methods of protein separation will be necessary to resolve the large number of proteins expected to be detectable with this sensitivity.
Synthesis and Properties of Selected 4-Substituted Anhydro Sugars
2000-07-01

A new class of 4-deoxy-4-([4-substituted-1-piperazinyl], [4-morpholinyl] and [4-(perhydrol, 4-thiazin-4-yl)])-2,3-anhydrolyxopyranosides (3a-g and 6a-g) were synthesized from epoxy triflate moities 2 and 5 and 4-substituted piperazines, morpholines and perhydro-1,4- thiazines, respectively, to test their antibacterial activity. The characterized series of new compounds was tested in vitro against E. coli ATCC11229, S. aureus ATCC6538 and C. albicans SATCC10231.
Tunnelling of topological line defects in strongly coupled superfluids
2000-07-01

Abstract The geometric theory of vortex tunnelling in superfluid liquids is developed. Geometry rules the tunnelling process in the approximation of an incompressible superfluid, which yields the identity of phase and configuration space in the vortex collective co‐ordinate. To exemplify the implications of this approach to tunnelling, we solve explicitly for the two‐dimensional motion of a point vortex in the presence of an ellipse, showing that the hydrodynamic collective co‐ordinate description limits the constant energy paths allowed for the vortex in configuration space. We outline the experimental procedure used in helium II to observe tunnelling events, and compare the conclusions we draw to the experimental results obtained so far. Tunnelling in Fermi superfluids is discussed, where it is assumed that the low energy quasiparticle excitations localised in the vortex core govern the vortex dynamical equations. The tunnelling process can be dominated by Hall or dissipative terms, respectively be under the influence of both, with a possible realization of this last intermediate case in unconventional, high‐temperature superconductors.
Deranged transcriptional regulation of cell-volume-sensitive kinase hSGK in diabetic nephropathy
2000-07-05

Transforming growth factor β (TGF-β) has been shown to participate in the pathophysiology of diabetic complications. As shown most recently, TGF-β stimulates the expression of a distinct serine/threonine kinase (hSGK) which had previously been cloned as an early gene transcriptionally regulated by cell volume alterations. The present study was performed to elucidate transcription and function of hSGK in diabetic nephropathy. As shown by Northern blotting, an increase of extracellular glucose concentration increased hSGK mRNA levels in cultured cells, an effect qualitatively mimicked by osmotic cell shrinkage or treatment with TGF-β (2 μg/liter), phorbol 12,13-didecanoate (1 μM), or the Ca 2+ ionophore ionomycin (1 μM) and blunted by high concentrations of nifedipine (10 and 100 μM). In situ hybridization revealed that hSGK transcription was markedly enhanced in diabetic nephropathy, with particularly high expression in mesangial cells, interstitial cells, and cells in thick ascending limbs of Henle's loop and distal tubules. According to voltage clamp and tracer flux studies in Xenopus oocytes expressing the renal epithelial Na + channel ENaC or the mouse thick ascending limb Na + ,K + ,2Cl − cotransporter BSC-1, coexpression with hSGK stimulated ENaC and BSC-1 11-fold and 6-fold, respectively, effects reversed by kinase inhibitors staurosporine (1 μM) and chelerythrine (1 μM) and not elicited by inactive hSGK. In conclusion, excessive extracellular glucose concentrations enhance hSGK transcription, which in turn stimulates renal tubular Na + transport. These observations disclose an additional element in the pathophysiology of diabetic nephropathy.
Conferring Selectivity to Chemical Sensors via Polymer Side-Chain Selection:  Thermodynamics of Vapor Sorption by a Set of Polysiloxanes on Thickness-Shear Mode Resonators
2000-07-08

Entropy of mixing is shown to be the driving interaction for the endothermic physisorption process of organic vapor partitioning into seven systematically side-chain-modified (polar, acidic, basic, polarizable side groups and groups interacting via H-bridges) polysiloxanes on thickness-shear mode resonators. Each sensor was exposed to seven analytes, selected for their diversity of functional groups. This systematic investigation of sorption yields benchmarking data on physisorption selectivity: response data and modeling reveal a direct correlation of partition coefficients with interactions between specific polymer side chains and analyte functional groups. Partition coefficients were determined for every polymer/analyte pairing over the 273-343 K range at 10 K intervals; from partition coefficient temperature dependence, overall absorption enthalpies and entropies were calculated. By subtracting the enthalpy and entropy of condensation for a given pure analyte, its mixing entropy (primarily combinatorial) and mixing enthalpy (associated with intermolecular interactions) with each polymer matrix were determined. These two crucial thermodynamic parameters determine the chemical selectivity patterns of the polymers for the analytes. Simple molecular modeling based on the polymer contact surface share of the modified side group or the introduced functional group reveals a direct correlation between the partition coefficients and the side-group variation.
Accelerating fronts in autocatalysis
2000-07-08

We consider a reaction–diffusion system modelling propagating fronts of an autocatalytic reaction of order m in a one–dimensional, infinitely extended medium. The Lewis number, i.e. the ratio of the molecular diffusivity of the autocatalyst to that of the reactant, is arbitrary. We prove that if the initial profile of the front decays exponentially or algebraically with exponent μ > 1/(m − 1), then the speed of the front is bounded for all times. Our method relies on weighted Lebesgue and Sobolev–space estimates, from which we can reconstruct pointwise results for the decay of the front via interpolation. The result gives both a functional analytic foundation, and an extension to arbitrary Lewis numbers, to the numerical studies of Sherratt & Marchant and the asymptotic analysis of Needham & Barnes.
Stroboscopic articulography using fast magnetic resonance imaging
2000-07-09

Abstract A method to display dynamic aspects of vocal tract configuration during speech production by means of fast magnetic resonance imaging is presented. Data acquisition during repetitive movement relies on a stroboscopy‐like procedure. The time resolution achieved is 120 images s −1 in a selected plane. As compared with other techniques of kinematic measurements of speech motor processes, this procedure allows for visualization of the temporal and spatial coordination of all relevant articulators, e.g. the entire tongue, the velum and the lower vocal tract. As an example, the method was applied to repetitions of stop consonant‐vowel‐nasal syllables.
Technical basis for immunoadsorption
2000-07-09

Summary Immunoadsorption is a new extracorporeal treatment for immunologicaly‐mediated diseases. This review deals with the primary plasma separation for immunoadsorption, the various immunoadsorbers and the technique of immunoadsorption itself. Primary plasma separation can be performed either by plasma membrane filtration or by centrifugation depending on the quantity of processed plasma. Currently, there are non‐selective, semi‐selective and highly selective adsorbers commercially available. Adsorbers can be subdivided into single‐use and reusable devices. The choice of the adsorber is dependent on the clinical situation of the patient. An adapted anticoagulant regimen must be used to avoid complications in the patient and to obtain optimal adsorber performance. Thus, immunoadsorption is an effective and safe extracorporal treatment in severely ill patients suffering from autoimmune diseases.
A new selection scheme for steady-state evolution strategies
2000-07-10

In this paper, a new selection scheme for a (m + 1) steady-state evolution strategy is described: the so-called median selection. In contrast to generational algorithms, only one individual is generated and evaluated in one step of the algorithm and is immediately integrated into the population. Previous steady-state algorithms are similar to the (m + l) selection scheme in evolution strategies, which has a disadvantage in the fast self-adaptation of mutation step-length. This is compensated by the presented median selection, which is oriented at the (m, l) selection. The median selection is compared with other steady-state selection schemes and with (m, l) selection. As a result, median selection achieves better or equally good results as the other selection schemes for a large number of benchmark functions. Additionally, it is shown that the use of a sequential steady-state evolution strategy is advantageous even on oneprocessor computers.
Workup-Dependent Formation of 5-Lipoxygenase Inhibitory Boswellic Acid Analogues
2000-07-11

Pentacyclic triterpenes from the 11-keto-boswellic acid series were identified as the active principal ingredients of Boswellia resin, inhibiting the key enzyme of leukotriene biosynthesis, 5-lipoxygenase (5-LO). Of the genuine boswellic acids hitherto characterized, 3-O-acetyl-11-keto-beta-boswellic acid, AKBA (1), proved to be the most potent inhibitor of 5-LO. In the course of purification of further boswellic acid derivatives from Boswellia resin, we observed the degradation of the natural compound 3-O-acetyl-11-hydroxy-beta-boswellic acid (2) to the thermodynamically more stable product 3-O-acetyl-9, 11-dehydro-beta-boswellic acid (4). The metastable intermediate of this conversion, under moderate conditions of workup in methanolic solutions, was identified as 3-O-acetyl-11-methoxy-beta-boswellic acid (3). The novel artifactual boswellic acid derivatives inhibited 5-LO product formation in intact cells with different characteristics: 4 almost totally abolished 5-LO activity, with an IC(50) of 0.75 microM, whereas 3 and 9,11-dehydro-beta-boswellic acid (5), the deacetylated analogue of 4, were incomplete inhibitors. The data suggest that the conditions chosen for the workup of Boswellia extracts could significantly influence the potency of their biological actions and their potential therapeutic effectiveness.
Adenosine formed by 5′-nucleotidase mediates tubuloglomerular feedback
2000-07-15

Nephron function is stabilized by tubuloglomerular feedback (TGF). TGF operates within the juxtaglomerular apparatus, sensing changes in tubular flow and eliciting compensatory changes in single nephron GFR (SNGFR). The mediator(s) of TGF remains unconfirmed. One theory is that ATP consumed in active transport by the macula densa leads to formation of adenosine, which causes glomerular vasoconstriction. We performed micropuncture in rats to test this hypothesis. Adenosine activity was manipulated by microperfusing nephrons with adenosine A1 receptor blocker, A1-agonist, or 5'-nucleotidase inhibitor. Effects on TGF were characterized by changes in TGF efficiency (the compensation for small perturbations in tubular flow) and by changes in the maximum range over which TGF can cause SNGFR to change. These data were further applied to generate TGF profiles [SNGFR versus late proximal flow (V(LP))]. TGF efficiency was significantly reduced by blocking A1-receptors. TGF efficiency, TGF range, and the slope of the TGF profile (DeltaSNGFR/DeltaV(LP)) were all significantly reduced by blocking 5'-nucleotidase. When adenosine activity was clamped by combining 5'-nucleotidase inhibitor with A1-agonist to determine whether TGF requires adenosine to be present or to fluctuate, the TGF slope was reduced by 83%, indicating that adenosine activity must fluctuate for normal TGF to occur and that adenosine is a mediator of TGF.
Transcriptional and Mutational Analyses of theStreptomyces lividans recXGene and Its Interference with RecA Activity
2000-07-15

ABSTRACT The role of the 20,922-Da RecX protein and its interference with RecA activity were analyzed in Streptomyces lividans . The recX gene is located 220 bp downstream of recA . Transcriptional analysis by reverse transcriptase PCR demonstrated that recX and recA constitute an operon. While recA was transcribed at a basal level even under noninducing conditions, a recA-recX cotranscript was only detectable after induction of recA following DNA damage. The recA-recX cotranscript was less abundant than the recA transcript alone. The recX gene was inactivated by gene replacement. The resulting mutant had a clearly diminished colony size, but was not impaired in recombination activity, genetic instability, and resistance against UV irradiation. Expression of an extra copy of the S. lividans recA gene under control of the thiostrepton-inducible tipA promoter was lethal to the recX mutant, demonstrating that RecX is required to overcome the toxic effects of recA overexpression. Since inactivation of the recX gene did not influence transcription of recA , the putative function of the RecX protein might be the downregulation of RecA activity by interaction with the RecA protein or filament.
Primary photoexcitations in oligophenylenevinylene thin films probed by femtosecond spectroscopy
2000-07-15

The photoexcited state dynamics of vapor-deposited oligophenylenevinylene films, with chain lengths of 3, and 4 vinylene units, is investigated with a 100-fs time resolution. The spectral signatures of three different species and are identified in the photoinduced absorption spectrum. Their assignment is based on kinetics, chain length dependence, and theoretical modeling. is attributed to the singlet-singlet transition. The population displays a strongly intensity dependent decay in the first ps due to bimolecular annihilation. is assigned to triplet-triplet absorption; the triplet state is populated within the pump pulse duration by a nonconventional mechanism which circumvents the spin-flip constraints. grows superlinearly with the pump intensity, and shows a distinct formation dynamics. It is assigned to radical ion pairs resulting from singlet coalescence. These results provide insight into the fluorescence quenching mechanisms of organic molecules in the solid state.