julilili42/papers huggingface dataset:
A New Subunit of the Epithelial Na+ Channel Identifies Regions Involved in Na+ Self-inhibition
2003-07-25

The epithelial Na+ channel (ENaC) is the apical entry pathway for Na+ in many Na+-reabsorbing epithelia. ENaC is a heterotetrameric protein composed of homologous alpha, beta, and gamma subunits. Mutations in ENaC cause severe hypertension or salt wasting in humans; and consequently, ENaC activity is tightly controlled. According to the concept of Na+ self-inhibition, the extracellular Na+ ion itself can reduce ENaC activity. The molecular basis for Na+ self-inhibition is unknown. Here, we describe cloning of a new ENaC subunit from Xenopus laevis (epsilonxENaC). epsilonxENaC can replace alphaxENaC and formed functional, highly selective, amiloride-sensitive Na+ channels when coexpressed with betaxENaC and gammaxENaC. Channels containing epsilonxENaC showed strong inhibition by extracellular Na+. This Na+ self-inhibition was significantly slower than for alphaxENaC-containing channels. Using site-directed mutagenesis, we show that the proximal part of the large extracellular domain controls the speed of self-inhibition. This suggests that this region is involved in conformational changes during Na+ self-inhibition.
An 17O NMR and Quantum Chemical Study of Monoclinic and Orthorhombic Polymorphs of Triphenylphosphine Oxide
2003-07-26

Solid-state (17)O NMR spectroscopy is employed to characterize powdered samples of known monoclinic and orthorhombic modifications of (17)O-enriched triphenylphosphine oxide, Ph(3)PO. Precise data on the orientation-dependent (17)O electric field gradient (EFG) and chemical shift (CS) tensors are obtained for both polymorphs. While the (17)O nuclear quadrupolar coupling constants (C(Q)) are essentially identical for the two polymorphs (C(Q) = -4.59 +/- 0.01 MHz (orthorhombic); C(Q) = -4.57 +/- 0.01 MHz (monoclinic)), the spans (Omega) of the CS tensors are distinctly different (Omega = 135 +/- 3 ppm (orthorhombic); Omega = 155 +/- 5 ppm (monoclinic)). The oxygen CS tensor is discussed in terms of Ramsey's theory and the electronic structure of the phosphorus-oxygen bond. The NMR results favor the hemipolar sigma-bonded R(3)P(+)-O(-) end of the resonance structure continuum over the multiple bond representation. Indirect nuclear spin-spin (J) coupling between (31)P and (17)O is observed directly in (17)O magic-angle-spinning (MAS) NMR spectra as well as in (31)P MAS NMR spectra. Ab initio and density-functional theory calculations of the (17)O EFG, CS, and (1)J((31)P,(17)O) tensors have been performed with a variety of basis sets to complement the experimental data. This work describes an interesting spin system for which the CS, quadrupolar, J, and direct dipolar interactions all contribute significantly to the observed (17)O NMR spectra and demonstrates the wealth of information which is available from NMR studies of solid materials.
VoxelCache: a cache-based memory architecture for volume graphics
2003-07-26

This paper presents a cache-based memory architecture for volume graphics. We describe the memory organization and cache logic to implement a voxel cache based on 43 voxel blocks. We show an efficient prefetching scheme that increases the cache hit ratio to more than 98% in most cases. The performance of the memory system with different types of external memory is demonstrated by a cycle accurate C++ simulation. The VoxelCache memory architecture is designed to be easily adapted to different memory technologies, because all volume graphics specific parts of the memory system are encapsulated inside the on-chip cache. The design is targeted at implementation on off-the-shelf reconfigurable hardware.
Interactive physically based solid dynamics
2003-07-26

The interactive simulation of deformable solids has become a major working area in Computer Graphics. We present a sophisticated material law, better suited for dynamical computations than the standard approaches. As an important example, it is employed to reproduce measured material data from biological soft tissue. We embed it into a state-of-the-art finite element setting employing an adaptive basis. For time integration the use of an explicit stabilized Runge-Kutta method is proposed.
CloN6, a Novel Methyltransferase Catalysing the Methylation of the Pyrrole‐2‐carboxyl Moiety of Clorobiocin
2003-07-28

Abstract The aminocoumarin antibiotic clorobiocin contains a 5‐methylpyrrole‐2‐carboxylic acid unit. This pyrrole unit is derived from L ‐proline, and it would be expected that its 5‐methyl group should be introduced by a methylation reaction. However, sequence analysis of the clorobiocin biosynthetic gene cluster did not reveal a gene with sequence similarity to the SAM‐dependent methyltransferases that could be assigned to this reaction. This study, however, has provided evidence that the gene cloN6 is involved in this methylation reaction. Its gene product CloN6 shares conserved sequence motifs with the recently identified radical SAM protein superfamily, and it has been suggested that members of this family can catalyse methylcobalamin‐dependent methylation reactions. cloN6 was inactivated in the clorobiocin producer Streptomyces roseochromogenes var. oscitans DS 12.976 by use of the PCR‐targeting method. The cloN6 − mutants accumulated, instead of clorobiocin, a derivative lacking the 5′′′‐methyl group of the pyrrole moiety (termed novclobiocin 109). A structural isomer carrying the pyrrole‐2‐carboxyl moiety at 2′′‐OH rather than at the 3′′‐OH of the deoxysugar (novclobiocin 110), and a derivative completely lacking the pyrrole unit (novclobiocin 104) were also identified. The structures of the metabolites were confirmed by NMR and MS analysis. Antibacterial activity tests against Bacillus subtilis showed that novclobiocin 109 and novclobiocin 110 have antibacterial activities about eight times less than that of clorobiocin, whereas novclobiocin 104 showed no activity under the test conditions.
Evidence that 5‐lipoxygenase and acetylated cyclooxygenase 2‐derived eicosanoids regulate leukocyte–endothelial adherence in response to aspirin
2003-07-30

Unlike other nonsteroidal anti‐inflammatory drugs that inhibit formation of cyclooxygenase (COX)‐dependent eicosanoids, acetylation of COX‐2 by aspirin switches eicosanoid biosynthesis from prostaglandin E 2 (PGE 2 ) to 15‐epi‐lipoxin A 4 (15‐epi‐LXA 4 or aspirin‐triggered lipoxin, ATL). ATL formation by activated leukocytes (PMN) requires the intervention of 5‐lipoxygenase (5‐LOX), an enzyme that is involved in leukotriene B 4 (LTB 4 ) formation. In the present study, we have examined the role of acetylated COX‐2 and 5‐LOX in modulating antiadhesive effects of aspirin on adhesion of PMN to endotoxin (LPS)‐primed human umbilical endothelial cells (HUVEC). Treating PMN/HUVEC cocultures with aspirin resulted in a concentration‐dependent inhibition of cell‐to‐cell adhesion induced by LPS. Treating HUVEC with selective COX‐2 inhibitors, celecoxib and rofecoxib, caused an ∼70% reversion of antiadhesive effect of aspirin. In contrast, inhibition of neutrophil's 5‐LOX pathway with 1 μ M ZD2138, a selective 5‐LOX inhibitor, 1 μ M BAY‐X‐1005, a FLAP inhibitor, or 100 μ M licofelone, a dual COX/5‐LOX inhibitor, did not affect antiadhesive properties of aspirin. Exposure to celecoxib (100 μ M ) or rofecoxib (10 μ M ) completely suppressed ATL formation caused by aspirin without affecting LTB 4 levels. ZD2138, licofelone and BAY‐X‐1005 inhibited ATL formation as well as LTB 4 generation. Treatment with LXA 4 reduced PMN adhesion to HUVEC and counteracted the proadhesive effect of celecoxib. In contrast, exposure to Boc‐1, an LXA 4 antagonist, counteracts the antiadhesive activities of aspirin. Exposure to U75302, an LTB 4 receptor antagonist, enhances the antiadesive effect of aspirin. Reversal of antiadhesive activities of aspirin by celecoxib was associated with increased expression of LFA‐1 on PMN and E‐selectin on HUVEC. Addition of LXA 4 , ZD2138 and U75302 inhibited these changes. The present results support the notion that inhibition of ATL formation is mechanistically linked to the reversal of the antiadhesive activity of aspirin caused by selective COX‐1 inhibitors and suggests that the LTB 4 /ATL balance modulates pro‐ and antiadhesive activity of nonsteroidal anti‐inflammatory drugs at the leukocyte–endothelial cell interface. British Journal of Pharmacology (2003) 139 , 1351–1359. doi: 10.1038/sj.bjp.0705356
Dilepton production in heavy-ion collisions at intermediate energies
2003-07-30

We present a unified description of the vector meson and dilepton production in elementary and in heavy ion reactions. The production of vector mesons ( ) is described via the excitation of nuclear resonances ( ). The theoretical framework is an extended vector meson dominance model (eVMD). The treatment of the resonance decays with arbitrary spin is covariant and kinematically complete. The eVMD includes thereby excited vector meson states in the transition form factors. This ensures correct asymptotics and provides a unified description of photonic and mesonic decays. The resonance model is successfully applied to the production in reactions. The same model is applied to the dilepton production in elementary reactions ( ). Corresponding data are well reproduced. However, when the model is applied to heavy ion reactions in the BEVALAC/SIS energy range the experimental dilepton spectra measured by the DLS Collaboration are significantly underestimated at small invariant masses. As a possible solution of this problem the destruction of quantum interference in a dense medium is discussed. A decoherent emission through vector mesons decays enhances the corresponding dilepton yield in heavy ion reactions. In the vicinity of the -peak the reproduction of the data requires further a substantial collisional broadening of the and in particular of the meson.
Electromagnetic nucleon-delta transition in the perturbative chiral quark model
2003-07-30

We apply the perturbative chiral quark model to the gamma N -&gt; Delta\\ntransition. The four momentum dependence of the respective transverse helicity\\namplitudes A(1/2) and A(3/2) is determined at one loop in the pseudoscalar\\nGoldstone boson fluctuations. Inclusion of excited states in the quark\\npropagator is shown to result in a reasonable description of the experimental\\nvalues for the helicity amplitudes at the real photon point.\\n
Moving black holes via singularity excision
2003-07-31

We present a singularity excision algorithm appropriate for numerical\\nsimulations of black holes moving throughout the computational domain. The\\nmethod is an extension of the excision procedure previously used to obtain\\nstable simulations of single, non-moving black holes. The excision procedure\\nalso shares elements used in recent work to study the dynamics of a scalarfield\\nin the background of a single, boosted black hole. The robustness of our\\nexcision method is tested with single black-hole evolutions using a coordinate\\nsystem in which the coordinate location of the black hole, and thus the\\nexcision boundary, moves throughout the computational domain.\\n
Fast enantiomeric separation with vancomycin as chiral additive by co‐electroosmotic flow capillary electrophoresis: Increase of the detection sensitivity by the partial filling technique
2003-07-31

Abstract A fast and sensitive method is described by using vancomycin as a chiral additive for enantiomeric separation by capillary electrophoresis (CE). In order to overcome disadvantages associated with use of vancomycin as chiral additive in CE, several strategies including the dynamic coating technique, the co‐electroosmotic flow technique, and the partial filling technique were employed sequentially in this method. Using the polycationic polymer hexadimethrine bromide (HDB) as a buffer additive, the capillary wall was dynamically coated with a thin film formed by the adsorbed HDB. Consequently, the adsorption of vancomycin onto the capillary wall was minimized via electrostatic repulsion between the coating of the capillary wall and the vancomycin molecule. In addition, the reversed electroosmotic flow (from cathode to anode) produced by the positively charged capillary wall migrates in the same direction of negatively charged analytes (co‐electroosmotic flow electrophoresis). Thereby the electrophoretic mobility of negatively charged analytes were drastically accelerated leading to a short separation time of less than 3.4 min. The separation time was further reduced by the use of a short‐end‐injection technique. For example, the analysis time was achieved by as short as 55 s for a baseline separation of dansyl‐α‐amino‐ n ‐butyric acid. Concurrently, the partial filling technique was used to avoid the loss of detection sensitivity caused by the presence of vancomycin in the running buffer. The effect of several parameters, such as HDB concentration, buffer pH, plug length of the chiral selector, concentration of the chiral selector and applied voltage, on enantioselectivity were investigated toward optimization. Besides the advantage of a very short separation time, the method is characterized by high detection sensitivity, high selectivity, and high efficiency.
Accuracy of the ImmunoCyt assay in the diagnosis of transitional cell carcinoma of the urinary bladder.
2003-07-31

The ImmunoCyt assay (Diagnocure Inc., Québec, Canada) is a new immunocytological fluorescence test for identifying two different mucins and a high-molecular-weight glycosylated carcinoembryonic antigen (CEA) present in tumours originating from transitional epithelial cells. The test promises a higher diagnostic sensitivity in transitional cell carcinoma (TCC) of the bladder than voided urine cytology. Our study was designed to evaluate this test especially for TaG1 carcinomas, which are characterised by a low detection rate in urinary cytology. A total of 121 spontaneous urine samples of 92 patients (age range 28 to 86, mean 62.5 years) were examined. The samples were taken from patients suspected of having TCC (41 out of 121) or tumor recurrence (46 out of 121), or who were part of a follow-up protocol (34 out of 121). Cystoscopy was practiced in all patients. The ImmunoCyt test was carried out according to the manufacturer's protocol. For cytology cytospins were made from the same urine samples and stained according to the method of Papanicolaou. One hundred and thirteen specimens could be evaluated. In 87 cystoscopy and/or histology were negative. There was histological evidence of 7 pTaG1, 4 pTaG2, 8 pT1G2/G3 and 7 pT2G2/G3 TCC. As for ImmunoCyt and cytology, specificity was 83.9% and 91.9%, respectively. A combination of either test indicated 81.6% specificity. The sensitivity amounted to 38.5% and 34.6%, respectively, and the combined sensitivity to 53.8%. The sensitivity for TaG1 carcinomas was 14.3% each, for TaG2 carcinomas 25% and 50%, for T1G2/G3 carcinomas it amounted to 37.5% each, while for T2G2/G3 carcinomas it was 71.4% and 42.9%, respectively. The higher sensitivity of the ImmunoCyt test as compared to urinary cytology renders improved identification of exfoliated tumour cells in bladder cancer possible. In our study, however, the expected increase in detecting TaG1 carcinomas was not found. Because of its lower specificity, the test should only be used in combination with voided urine cytology. On account of its low sensitivity, the ImmunoCyt test cannot replace cystoscopy (with biopsy) in the diagnosis and monitoring of bladder cancer.
Quantitation of talinolol and other β‐blockers by capillary electrophoresis for in vitro drug absorption studies
2003-07-31

Abstract A capillary zone electrophoresis method is described for the enantioseparation of talinolol using heptakis(2,3‐diacetyl‐6‐sulfo)‐β‐cyclodextrin (HDAS‐β‐CD) as a chiral selector. After liquid‐liquid extraction of talinolol from physiological solution, electrokinetic injection was employed to improve the sensitivity. The use of a coated capillary was necessary to achieve stable and reproducible enantioseparations. A baseline separation of the talinolol enantiomers was achieved in less than 10 min using 100 m M phosphate solution as background electrolyte and pH 3.5, at the presence of 3.0 m M HDAS‐β‐CD and at 20°C. In addition, this analytical condition proved to be useful for the enantioseparation of a number of other β‐blocking agents such as alprenolol, atenolol, bisoprolol, celiprolol, metipranolol, oxprenolol, and sotalol. For determing talinolol, the method could be validated in terms of precision, accuracy and linearity, and was found to be suitable in determination of talinolol enantiomers in highly diluted samples obtained from in vitro experiments.
Computed tomographic findings in bourneville-pringle disease.
2003-07-31

Bourneville-Pringle disease (synonym: tuberous sclerosis, epiploia) is a neuroectodermal disorder. A characteristic clinical triad of adenoma sebaceum, mental retardartion, and seizures leads to early childhood diagnosis. Many patients show morphological changes of the visceral organs, vascular, and skeletal system. We review the computed tomographic findings of Bourneville-Pringle disease as relates to an oligosymptomatic 36-year-old woman with late onset of clinical symptoms.
Tubuloglomerular Feedback and the Control of Glomerular Filtration Rate
2003-08-01

In every nephron the glomerular filtration rate is adapted to changes in the salt concentration of early distal tubular fluid through the mechanism of tubuloglomerular feedback. Recent studies indicate that adenosine and possibly ATP mediate this mechanism and demonstrate its role in glomerular hemodynamic alterations in the early diabetic kidney.
Alanylation of Teichoic Acids ProtectsStaphylococcus aureusagainst Toll‐like Receptor 2–Dependent Host Defense in a Mouse Tissue Cage Infection Model
2003-08-01

Staphylococcus aureus is inherently resistant to cationic antimicrobial peptides because of alanylation of cell envelope teichoic acids. To test the effect of alanylated teichoic acids on virulence and host defense mediated by Toll-like receptor 2 (TLR2), wild-type (wt) S. aureus ATCC35556 (S.a.113) and its isogenic mutant expressing unalanylated teichoic acids (dlt(-)) were compared in a tissue cage infection model that used C57BL/6 wt and TLR2-deficient mice. The minimum infective doses (MID) to establish persistent infection with S.a.113 were 10(3) and 10(2) colony-forming units (cfu) in wt and TLR2(-/-) mice, respectively. The corresponding MID for dlt(-) were 5x105 and 10(3) cfu in wt and TLR2(-/-) mice, respectively. Both mouse strains showed bacterial-load-dependent inflammation with elevations in tumor necrosis factor, macrophage inflammatory protein 2, and leukocytes, with increasing proportions of dead cells. These findings indicate that alanylated teichoic acids contribute to virulence of S. aureus, and TLR2 mediates host defense, which partly targets alanylated teichoic acids.
Synchronised Business Cycles in East Asia and Fluctuations in the Yen/Dollar Exchange Rate
2003-08-01

Because many authors have proposed stimulating the ailing Japanese economy by monetary expansion and yen depreciation, we explore the repercussions of depreciating the yen against the dollar on the other East Asian economies – which largely peg to the dollar. Since 1980, economic integration among Japan's neighbours – China, Hong Kong, Indonesia, Korea, Malaysia, Philippines, Singapore and Thailand – has intensified and (except for China and Singapore) their business cycles have been highly synchronised. These cycles have been closely linked to fluctuations in the yen/dollar exchange rate – through changes in the export competitiveness, inflows of foreign direct investment and intra‐Asian income effects. We show that a major yen devaluation would have a negative impact on incomes in other East Asian economies and that it is not a sensible policy option for Japan.
Pyramidal Tract Damage Correlates with Motor Dysfunction in Bilateral Periventricular Leukomalacia (PVL)
2003-08-01

In children with periventricular leukomalacia (PVL), motor dysfunction is thought to be related to involvement of pyramidal tract fibres in the periventricular white matter. The purpose of the present study was to test this hypothesis. Thirteen former preterm adolescents with PVL, ten of whom were suffering from bilateral spastic cerebral palsy, were studied by MRI. The severity of pyramidal tract damage was assessed on semicoronal MRI reconstructions along anatomical landmarks of somatotopy in the precentral gyrus and the internal capsule; for comparison, the overall volume of cerebral white matter (determined by automated volumetry) served as a global measure of lesion severity. The motor dysfunction of each of the four extremities correlated much more strongly with the severity of pyramidal tract damage assessed on the respective MRI reconstruction (range of correlation coefficients, 0.647 to 0.922) than with the total volume of white matter (range of correlation coefficients, - 0.458 to - 0.212; Spearman). These findings corroborate the notion that an involvement of pyramidal tract fibres in the periventricular white matter is indeed a relevant factor for motor dysfunction in children with PVL.
A newly defined Late Ordovician magmatic‐thermal event in the Mt Painter Province, northern Flinders Ranges, South Australia
2003-08-01

Magmatism, metamorphism and metasomatism in the Palaeoproterozoic-Mesoproterozoic Mt Painter Inlier and overlying Neoproterozoic Adelaidean rocks in the northern Flinders Ranges (South Australia) have previously been interpreted as resulting from the ca 500 Ma Delamerian Orogeny. New Rb-Sr, Sm-Nd and U-Pb data, as well as structural analysis, indicate that the area also experienced a second thermal event in the Late Ordovician (ca 440 Ma). The Delamerian Orogeny resulted in large-scale folding, prograde metamorphism and minor magmatic activity in the form of a small volume of pegmatites and leucogranites. The Late Ordovician event produced larger volumes of granite (the British Empire Granite in the core of the inlier) and these show Nd isotopic evidence for a mantle component. The high-temperature stage of this magmatic-hydrothermal event also gave rise to unusual diopside-titanite veins and the primary uranium mineralisation in the basement, of which the remobilisation was younger than 3.5 Ma. It is possible that parts of the Mt Gee quartz-hematite epithermal system developed during the waning stages of the Late Ordovician event. We suggest that the Ordovician hydrothermal system was also the cause of the commonly observed retrogression of Delamerian metamorphic minerals (cordierite, andalusite) and the widespread development of actinolite, scapolite, tremolite and magnetite in the cover sequences. Deformation during the Late Ordovician was brittle. The recognition of the Late Ordovician magmatic-hydrothermal event in the Mt Painter Province might help to link the tectonic evolution of central Australia and the southeast Australian Lachlan Fold Belt.
Protein Kinase C Activation Downregulates Human Organic Anion Transporter 1-Mediated Transport through Carrier Internalization
2003-08-01

Organic anion transport in intact renal proximal tubule cells in animal model systems is downregulated by treatments that activate protein kinase C (PKC). How this downregulation is achieved is not yet known. Stimulation of PKC with sn-1,2-dioctanoylglycerol resulted in strong inhibition of p-aminohippurate transport mediated by the cloned human organic anion transporter 1 (hOAT1) expressed in Xenopus oocytes and HEK293 cells, as well as hOAT1 internalization in both expression systems. The sn-1,2-dioctanoylglycerol-induced transport inhibition was partially prevented by staurosporine. It was independent of the conserved canonical PKC consensus sites in hOAT1, however, and was unaffected by agents that destabilize actin filaments or microtubules, which altered baseline hOAT1-mediated p-aminohippurate uptake activity in oocytes. It is concluded that PKC-induced hOAT1 downregulation is achieved through carrier retrieval from the cell membrane and does not involve phosphorylation of the predicted classic hOAT1 PKC consensus sites.