julilili42/papers huggingface dataset:
Effect of chronic administration of <i>Boerhaavia diffusa</i> Linn. leaf extract on experimental diabetes in rats
2007-07-27

Purpose: The root and aerial parts of Boerhaavia diffusa Linn. (Nyctaginaceae) were used in Ayurveda for the treatment of diabetes. The present study is aimed at evaluating the antidiabetic activity of chloroform extract of Boerhaavia diffusa leaves on chronic administration in streptozotocin-induced non-insulin-dependent diabetes mellitus (NIDDM) model diabetic rats. Methods: The blood glucose lowering activity of the leaf extract was studied in streptozotocin-induced (65 mg/kg, i.v.) NIDDM model diabetic rats after oral administration of the extract at daily doses of 50, 100 and 200 mg/kg body weight for four weeks and compared with glibenclamide. Blood samples were collected from the tail vein before and also at weekly intervals for four weeks from the first dose of drug administration and blood glucose was analyzed by glucose-oxidase method using a visible spectrophotometer. Results: The leaf extract of B. diffusa produced dose-dependent reduction in blood glucose in streptozotocin-induced NIDDM rats comparable to that of glibenclamide. The results indicate that the reduction in blood glucose produced by the extract is probably through rejuvenation of pancreatic b-cells or through extrapancreatic action. Conclusion: The chloroform extract of Boerhaavia diffusa has significant antidiabetic activity and this supports the traditional usage of the plant by Ayurvedic physicians for the control of diabetes. Keywords: Blood glucose, Boerhaavia diffusa, Diabetes mellitus Streptozotocin, Rats> Tropical Journal of Pharmaceutical Research Vol. 3 (1) 2004: pp. 305-309
Optical Biosensor for the Determination of Trace Pollutants in the Environment
2007-07-27

Abstract A robust, cost‐effective, automated, and immunoassay‐based water analysis system is used to determine several organic pollutants at low concentration levels (a few nanograms per liter) without requiring any time‐consuming sample preconcentration or pretreatment. This system uses total internal reflection fluorescence (TIRF) as the transduction method employing bulk as well as integrated optical waveguides to allow low limits of detection and quantification. More than 20 analytes have been determined. The system allows remote operation and automated data processing; evaluation strategies and the results of field tests are discussed. Pollutant values exceeding predefined threshold values cause an alarm signal via telemetry.
The EssentialtacFGene Is Responsible for the Choline-Dependent Growth Phenotype ofStreptococcus pneumoniae
2007-07-28

ABSTRACT Streptococcus pneumoniae has an absolute nutritional requirement for choline, and the choline molecules are known to incorporate exclusively into the cell wall and membrane teichoic acids of the bacterium. We describe here the isolation of a mutant of strain R6 in which a single G→T point mutation in the gene tacF (formerly designated spr1150 ) is responsible for generating a choline-independent phenotype. The choline-independent phenotype could be transferred to the laboratory strain R6 and to the encapsulated strain D39 by genetic transformation with a PCR product or with a plasmid carrying the mutated tacF gene. The tacF gene product belongs to the protein family of polysaccharide transmembrane transporters (flippases). A model is presented in which TacF is required for the transport of the teichoic acid subunits across the cytoplasmic membrane. According to this model, wild-type TacF has a strict specificity for choline-containing subunits, whereas the TacF present in the choline-independent mutant strain is able to transport both choline-containing and choline-free teichoic acid chains. The proposed transport specificity of parental-type TacF for choline-containing subunits would ensure the loading of the cell wall with teichoic acid chains decorated with choline residues, which appear to be essential for the virulence of this pathogen.
Docking of the Periplasmic FecB Binding Protein to the FecCD Transmembrane Proteins in the Ferric Citrate Transport System ofEscherichia coli
2007-07-28

ABSTRACT Citrate-mediated iron transport across the cytoplasmic membrane is catalyzed by an ABC transporter that consists of the periplasmic binding protein FecB, the transmembrane proteins FecC and FecD, and the ATPase FecE. Salt bridges between glutamate residues of the binding protein and arginine residues of the transmembrane proteins are predicted to mediate the positioning of the substrate-loaded binding protein on the transmembrane protein, based on the crystal structures of the ABC transporter for vitamin B 12 , consisting of the BtuF binding protein and the BtuCD transmembrane proteins (E. L. Borths et al., Proc. Natl. Acad. Sci. USA 99:16642-16647, 2002). Here, we examined the role of the residues predicted to be involved in salt-bridge formation between FecB and FecCD by substituting these residues with alanine, cysteine, arginine, and glutamate and by analyzing the citrate-mediated iron transport of the mutants. Replacement of E93 in FecB with alanine [FecB(E93A)], cysteine, or arginine nearly abolished citrate-mediated iron transport. Mutation FecB(E222R) nearly eliminated transport, and FecB(E222A) and FecB(E222C) strongly reduced transport. FecD(R54C) and FecD(R51E) abolished transport, whereas other R-to-C mutations in putative interaction sites between FecCD and FecB substantially reduced transport. The introduced cysteine residues in FecB and FecCD also served to examine the formation of disulfide bridges in place of salt bridges between the binding protein and the transmembrane proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis results suggest cross-linking of FecB(E93C) to FecD(R54C) and FecB(E222C) to FecC(R60C). The data are consistent with the proposal that FecB(E93) is contained in the region that binds to FecD and FecB(E222) in the region that binds to FecC.
Circulating Retinol-Binding Protein-4, Insulin Sensitivity, Insulin Secretion, and Insulin Disposition Index in Obese and Nonobese Subjects
2007-07-28

In the recent article by Broch et al. (1), circulating retinol-binding protein-4 (RBP4) (measured by nephelometry) was not correlated with adiposity or insulin sensitivity; however, negative correlations with indexes of insulin secretion were detected. The authors concluded that RBP4 may impair β-cell function in human subjects. This is an interesting hypothesis, particularly because retinol seems to be required for adequate glucose-stimulated insulin secretion (2). However, retinoids in blood are not exclusively transported by RBP4 but also by albumin and lipoprotein particles (3). This suggests that the availability of retinoids in ...
ETHICAL ASPECTS OF LIMITING RESIDENTS' WORK HOURS
2007-07-28

ABSTRACT Definition of the problem: The regulation of residents' work hours involves several ethical conflicts which need to be systematically analysed and evaluated. Arguments and conclusion: The most important ethical principle when regulating work hours is to avoid the harm resulting from the over‐work of physicians and from an excessive division of labour. Additionally, other ethical principles have to be taken into account, in particular the principles of nonmaleficence and beneficence for future patients and for physicians. The article presents arguments for balancing the relevant ethical principles and analyses the structural difficulties that occur unavoidably in any regulation of the complex activities of physicians.
Efficacy and Tolerability of Temozolomide in an Alternating Weekly Regimen in Patients With Recurrent Glioma
2007-07-30

Purpose Evaluation of toxicity and efficacy of an alternating weekly regimen of temozolomide administered 1 week on and 1 week off in patients with recurrent glioma. Patients and Methods Ninety adult patients with recurrent gliomas accrued in one center received chemotherapy with temozolomide at 150 mg/m 2 /d (days 1 through 7 and 15 through 21 every 4 weeks) with individual dose adjustments according to hematologic toxicity. Results A total of 906 treatment weeks were delivered. Grade 4 hematotoxicity according to the Common Terminology Criteria for Adverse Events (CTCAE; version 3.0) was observed in 24 treatment weeks (2.6%). CTCAE grade 4 lymphopenia eventually developed in 11 patients (12%). There were neither cumulative lymphopenias nor opportunistic infections. The progression-free survival (PFS) rate at 6 months for glioblastoma patients was 43.8%. The median PFS in these patients was 24 weeks (95% CI, 17 to 26 weeks), the median survival time from diagnosis of progression was 38 weeks (95% CI, 30 to 46 weeks), and the 1-year survival rate from progression was 23%. O 6 -methylguanine DNA methyltransferase (MGMT) gene promoter methylation in the tumor tissue was not associated with longer PFS (log-rank P = .37). Conclusion These data imply that the alternating weekly schedule is feasible, safe, and effective and clearly warrants investigation in randomized studies. Compared with more protracted low-dose temozolomide schedules, the 1-week-on/1-week-off schedule may be less toxic. We provide preliminary evidence that this dose-dense schedule is also active in patients with tumors lacking MGMT gene promoter methylation.
The Arabidopsis AtPNG1 gene encodes a peptide: N‐glycanase
2007-07-30

Summary Deglycosylation of misfolded proteins by the endoplasmic reticulum‐associated degradation (ERAD) pathway is catalyzed by peptide: N ‐glycanases (PNGases) that are highly conserved among mammals and yeast. The catalytic mechanism of PNGases employs a catalytic triad consisting of Cys, His and Asp residues, which is shared by other enzyme families such as cysteine proteases and protein cross‐linking transglutaminases (TGases). In contrast to the yeast and mammalian systems, very little is known about ERAD in plants and the enzymes responsible for proper clearance of misfolded plant proteins. We have used a computer‐based modeling approach to identify an Arabidopsis thaliana PNGase (AtPNG1). AtPNG1 is encoded by a single‐copy gene and displays high structural homology with known PNGases. Importantly, heterologous expression of AtPNG1 restored N ‐glycanase activity in a PNGase‐deficient Saccharomyces cerevisiae mutant. The AtPNG1 gene is uniformly and constitutively expressed at low levels throughout all developmental stages of the plant, and its expression does not appear to be subject to substantial regulation by external stimuli. Recently, recombinant AtPNG1 produced in Escherichia coli was reported to display TGase activity (Della Mea et al. , Plant Physiol . 135, 2046–54, 2004). However, inactivation of the AtPNG1 gene did not result in decreased TGase activity in the mutant plant, and recombinant AtPNG1 produced in S. cerevisiae exhibited only residual TGase activity. We propose that the AtPNG1 gene encodes a bona fide peptide: N ‐glycanase that contributes to ERAD‐related protein quality control in plants.
Synthese von Y2O2(CN2) und Leuchtstoffeigenschaften von Y2O2(CN2):Eu
2007-07-30

Abstract Synthesis of Y 2 O 2 (CN 2 ) and Luminescence Properties of Y 2 O 2 (CN 2 ):Eu Crystalline powders of the new compound Y 2 O 2 (CN 2 ) were prepared by solid state reactions from different mixtures of YCl 3 /YOCl/Y 2 O 3 and Li 2 (CN 2 ) at temperatures between 620 °C and 650 °C. Structure refinements based on X‐ray powder diffraction revealed that trigonal Y 2 O 2 (CN 2 ) crystallizes with a structure that is closely related to that of Y 2 O 2 S, whereas linear N‐C‐N units replace sulphur atoms in Y 2 O 2 S. In addition, a hexagonal polytype of Y 2 O 2 (CN 2 ) was obtained in which a different stacking sequence of yttrium atoms creates a doubling of the c‐axis. Europium‐doped samples of Y 2 O 2 (CN 2 ) were prepared and the luminescence properties of Y 2 O 2 (CN 2 ):Eu are presented.
Cadherin-9 Is a Novel Cell Surface Marker for the Heterogeneous Pool of Renal Fibroblasts
2007-07-31

Cadherin-9 represents a novel and reliable cell surface marker for fibroblasts in healthy and diseased kidneys. Together with the established marker molecules FSP1, CD45 and alpha smooth muscle actin, cadherin-9 can now be used to differentiate the heterogenic pool of renal fibroblasts into resident and activated fibroblasts, immigrated bone marrow derived fibroblast precursors and cells in different stages of epithelial mesenchymal transition.
Stimulated PI3K-AKT Signaling Mediated through Ligand or Radiation-Induced EGFR Depends Indirectly, but not Directly, on Constitutive K-Ras Activity
2007-08-01

Abstract Previous results showed an inducible radiation sensitivity selectively observable for K-RAS–mutated cell lines as a function of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor blockade of phosphatidylinositol 3-kinase (PI3K)-AKT signaling. Therefore, the role of K-Ras activity for a direct (i.e., through activation of PI3K by K-Ras) or an indirect stimulation of PI3K-AKT signaling (through K-Ras activity–dependent EGFR ligand production) was investigated by means of small interfering RNA and inhibitor approaches as well as ELISA measurements of EGFR ligand production. K-RASmt tumor cells presented a constitutively activated extracellular signal–regulated kinase-1/2 signaling, resulting in enhanced production and secretion of the EGFR ligand amphiregulin (AREG). Medium supernatants conditioned by K-RASmt tumor cells equally efficiently stimulated EGFR signaling into the PI3K-AKT and mitogen-activated protein kinase pathways. Knocking down K-Ras expression by specific small interfering RNA markedly affected autocrine production of AREG, but not PI3K-AKT signaling, after treatment of K-RAS–mutated or wild-type cells with EGFR ligands or exposure to ionizing radiation. These results indicate that PI3K-mediated activation of AKT in K-RASmt human tumor cells as a function of EGFR ligand or radiation stimulus is independent of a direct function of K-Ras enzyme activity but depends on a K-Ras–mediated enhanced production of EGFR ligands (i.e., most likely AREG) through up-regulated extracellular signal–regulated kinase-1/2 signaling. The data provide new differential insight into the importance of K-RAS mutation in the context of PI3K-AKT–mediated radioresistance of EGFR-overexpressing or EGFR-mutated tumors. (Mol Cancer Res 2007;5(8):863–72)
MINERALS OF THE SYSTEM Bi Te Se S RELATED TO THE TETRADYMITE ARCHETYPE: REVIEW OF CLASSIFICATION AND COMPOSITIONAL VARIATION
2007-08-01

Our compilation of ~900 published results of analyses for minerals of the tetradymite series (tellurobismuthite, tetradymite, guanajuatite, paraguanajuatite, kawazulite, skippenite, tsumoite, hedleyite, pilsenite, laitakarite, ikunolite, joseite-A, joseite-B) allows compositional fields among naturally occurring Bi–Te–Se–S compounds to be established. New compositional data for ingodite, laitakarite, pilsenite, kawazulite and tellurobismuthite extend previously known compositional limits. Recognized minerals can, for the most part, be satisfactorily and conveniently classified according to the ratio Bi(+ Pb)/(Te + Se + S), into the subsystems (isoseries) Bi 2 Te 3 –Bi 2 Se 3 –Bi 2 S 3 , Bi 4 Te 3 –Bi 4 Se 3 –Bi 4 S 3 and BiTe–BiSe–BiS. Most minerals show limited compositional variation, but this is generally more extensive in the Se-bearing phases ( e.g., laitakarite) and in certain members of the system Bi–Te, such as hedleyite and tsumoite. Substitution of minor Pb for Bi is widespread throughout the group, especially in the Bi 4 Te 3 –Bi 4 Se 3 –Bi 4 S 3 subgroup. Several possible additional minerals or compositional variants of existing minerals would appear to exist in nature, including Bi 4 Te 2 Se, Bi 4 Te(Se,S) 2 , Bi 3 Te 2 Se and Bi 3 (Te,S,Se) 4 . Within the above groups, Bi(+ Pb)/(Te + Se + S) stoichiometry is remarkably constant, in accordance with known and derived structures in which all phases (except those in which Pb is essential) can be envisaged in terms of various combinations of nonvalent five-atom Bi 2 X 3 and two-atom Bi 2 layers. Deviation from Bi(+ Pb)/(Te + Se + S) stoichiometry within the isoseries may be linked to stacking disorder. Noting the appearance of many other phases and stoichiometries in experimental work in the system Bi–Te–Se–S and its subsystems, as well as the homologous character of this series, we predict that a significant number of additional mineral phases exist in nature and will be discovered in the future. Many of these, however, cannot be identified by chemical microanalysis alone.
Fully Adaptive Fault-Tolerant Routing Algorithm for Network-on-Chip Architectures
2007-08-01

In this paper, we present a novel fully adaptive and fault-tolerant routing algorithm for Network-on-Chips (NoCs) called Force-Directed Wormhole Routing (FDWR). The proposed routing algorithm is implemented in the switches of a TLM (Transaction Level Model) packet switching NoC using SystemC. Based on these switches, mesh, torus, and hypercube topologies for NoCs can be automatically generated. We show how the proposed algorithm distributes the traffic uniformly across the entire network to avoid overloaded links. Simulation results depict that the proposed routing algorithm is able to route packets even in the case of faulty links or switches in the NoC. Furthermore, it is shown that in the case of faulty switches the area around that switches is not overloaded and that the traffic is uniformly distributed across the entire network.
Microwave-Assisted Ring Opening of Epoxides:  A General Route to the Synthesis of 1-Aminopropan-2-ols with Anti Malaria Parasite Activities
2007-08-01

A series of 1-aminopropan-2-ols were synthesized and evaluated against two strains of malaria, Plasmodium falciparum FCR3 (chloroquine-resistant) and 3D7 (chloroquine-sensitive). Microwave-assisted ring opening of epoxides (aryl and alkyl glycidyl ethers, glycidol, epichlorohydrin) with various amines without catalysts generated the desired library of beta-amino alcohols rapidly and efficiently. Most of the compounds showed micromolar potency against malaria, with seven of them having IC50 values between 1 and 10 microM against both Plasmodium falciparum strains.
Juvenile and Adult Congenital Heart Disease: Time-resolved 3D Contrast-enhanced MR Angiography
2007-08-01

Compared with conventional MR angiography, time-resolved MR angiography yields clinically relevant information in a substantial number of patients; hence, the two techniques should be regarded as complementary.
Algorithmic funnel‐and‐gate system design optimization
2007-08-01

Funnel‐and‐gate systems (FGSs), which constitute a common variant of permeable reactive barriers used for in situ treatment of groundwater, pose particular challenges to the task of design optimization. Because of the complex interplay of funnels and gates, the evolutionary algorithms applied have to cope with multimodality, nonseparability, and nonlinearity of the optimization task. We analyze these features in a test case, introducing an objective function for design cost and constraints to account for plume capture and detention time in the gate reactors. We show that the derandomized evolution strategy with covariance matrix adaptation (CMA‐ES) does solve the given design optimization problem with high success rates. We further examine the performance of the algorithm for the example of four‐gate systems in three heterogeneous template aquifers. Here a special focus is set on the parameterization of the FGS (i.e., the problem encoding). The comparison of three different encodings reveals their significance concerning the search progress and its success. Among the found optimal and near‐optimal design solutions, mutual patterns were recognized. In particular, a large central barrier seems to be a superior feature.
In vitro analysis of hGH secretion in the presence of mutations of amino acids involved in zinc binding
2007-08-01

Zinc (Zn 2+ ) binding by human GH through amino acid residues His18, His21, and Glu174 has been described as a prerequisite for GH dimerization and storage in secretory granules. Our aim was to investigate in vitro whether disturbed Zn 2+ binding of mutant GH inhibits wild-type GH (wtGH) secretion and contributes to the pathogenetic mechanisms involved in dominantly transmitted isolated GH deficiency type II. Seven expression vectors harboring mutated human GH cDNAs were constructed in which nucleotide triplets encoding histidine or glutamine at positions 18, 21, and 174 were mutated to triplets encoding alanine: H18A, H21A, G174A, H18A–G174A, H21A–G174A, H18A–H21A, and H18A–H21A–G174A. These vectors were transiently cotransfected with a vector encoding wtGH or were singly transfected into rat pituitary GH 4 C 1 cells. Plasmids encoding β -galactosidase were cotransfected. 48h after transfection, GH in media and cell extracts was measured using a GH-specific RIA, and results were normalized for transfection efficiency by means of β -galactosidase activity. In comparison with the control transfection (wtGH/wtGH set at 100%), GH secretion remained unaffected when coexpressing wtGH and any of the GH mutants in which Zn 2+ binding was partially or completely prevented. When these mutants were singly expressed, the amount of GH in both media and cell extracts was decreased by about 50% when compared with cells expressing only wtGH. Our in vitro data do not support the hypothesis of disturbed Zn 2+ binding as a major pathogenetic mechanism in dominantly transmitted GH deficiency.
Association of strength with patellar tendinopathy in female runners
2007-08-01

Muscle weakness and muscle imbalance may lead to musculotendinous injuries since the energy absorption capacity of the affected muscle tendon unit is reduced. The purpose of this study was to investigate the maximum strength and strength endurance of the thigh musculature in healthy female runners (F: n=26) and female runners suffering from patellar tendinopathy (PT: n=20). Isokinetic strength measurements were recorded in a seated position. Primary outcome variables were maximum concentric and eccentric peak torque (at 60°/s) and concentric hamstrings-quadriceps-quotient (HQQ). Secondary outcome variables were relative peak torques [Nm/kilogram] and eccentric endurance quotient calculated as the ratio of muscle strength at the end of a 1-minute exercise compared to at the beginning of the exercise period. The primary outcome variables were analyzed using Student's t-test for each measure(α = 0.05). Secondary outcome variables were qualified descriptively. The results showed no statistically significant differences between injured and healthy female runners in concentric and eccentric peak torque or HQQ. Secondary outcome variables also failed to show inter-group differences. We therefore conclude that these variables are not relevant with respect to PT in female runners.
Synthesis of Some Ethyl 3-(Aryldiazenyl)-7-oxo-dihydropyrido[ 2,3-f]quinoxaline-8-carboxylates
2007-08-01

Ethyl 7,8-diamino-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate (6) and its free acid 7 are prepared by chemical reduction of the respective 7-azido-8-nitroquinoline 5. Consecutive nucleophilic addition and cyclocondensation reactions of 6 with α-acetyl-N-arylhydrazonoyl chlorides 8a - c in ethanol and triethylamine are site-selective and yield the corresponding 3-(aryldiazinyl)- 2-methylpyrido[2,3- f ]quinoxalines 10a - c. Analytical and spectral (IR, MS, NMR) data of 6, 7, and 10a - c are in conformity with the assigned structures.