julilili42/papers huggingface dataset:
Backbone dynamics of the human MIA protein studied by 15N NMR relaxation: Implications for extended interactions of SH3 domains
2003-02-18

Abstract The melanoma inhibitory activity (MIA) protein is a clinically valuable marker in patients with malignant melanoma as enhanced values diagnose metastatic melanoma stages III and IV. Here, we report the backbone dynamics of human MIA studied by 15 N NMR relaxation experiments. The folded core of human MIA is found to be rigid, but several loops connecting β‐sheets, such as the RT‐loop for example, display increased mobility on picosecond to nanosecond time scales. One of the most important dynamic features is the pronounced flexibility of the distal loop, comprising residues Asp 68 to Ala 75, where motions on time scales up to milliseconds occur. Further, significant exchange contributions are observed for residues of the canonical binding site of SH3 domains including the RT‐loop, the n‐Src loop, for the loop comprising residues 13 to 19, which we refer to as the“disulfide loop”, in part for the distal loop, and the carboxyl terminus of human MIA. The functional importance of this dynamic behavior is discussed with respect to the biological activity of several point mutations of human MIA. The results of this study suggest that the MIA protein and the recently identified highly homologous fibrocyte‐derived protein (FDP)/MIA‐like (MIAL) constitute a new family of secreted proteins that adopt an SH3 domain‐like fold in solution with expanded ligand interactions.
Lipid content in the musculature of the lower leg assessed by fat selective MRI: Intra‐ and interindividual differences and correlation with anthropometric and metabolic data
2003-02-19

Abstract Purpose To assess the muscular lipid content (LC) in different muscle groups of the lower leg by a magnetic resonance imaging technique working with chemical shift selective excitation, and comparison with anthropometric and metabolic data. Materials and Methods Examinations were performed in 67 volunteers (54 male/13 female, age 29 ± seven years) on a 1.5 T whole body imager, applying a highly selective spectral‐spatial technique for fat selective MRI. LC was measured in six calf muscles and correlated with body mass index (BMI), percent body fat (PFAT), and insulin sensitivity (IS) of the subjects. Results Mean muscular LC of all subjects was between 2.0% (Tibialis posterior [TP]) and 3.8% (Peroneus muscles) with female subjects showing a significantly higher LC in all muscle groups ( P &lt; 0.05 each). LCs correlated moderately with BMI ( R between 0.39 [TP] and 0.53 [GM]) and with PFAT ( R between 0.38 [TP] and 0.62 [GM]). Insulin‐resistant subjects showed slightly but not significantly increased LC compared to insulin‐sensitive subjects in BMI‐matched subgroups. Conclusion The fat‐selective MRI technique allows a reliable non‐invasive measure of muscular lipids – even in muscle groups with inherent low LC – within a relatively short measurement time of about three minutes. The presented data reveal interesting interrelationships between LC and anthropometric and metabolic data, and therefore provide new insight into muscular fat metabolism. J. Magn. Reson. Imaging 2003;17:350–357. © 2003 Wiley‐Liss, Inc.
AtDUR3 Encodes a New Type of High-Affinity Urea/H+ Symporter in Arabidopsis
2003-02-21

Urea is the major nitrogen form supplied as fertilizer in agricultural plant production but also an important nitrogen metabolite in plants. We report the cloning and functional characterization of AtDUR3, a high-affinity urea transporter in plants. AtDUR3 contains 14 putative transmembrane-spanning domains and represents an individual member in Arabidopsis that belongs to a superfamily of sodium-solute symporters. Heterologous expression in urea uptake-defective yeast as well as two-electrode voltage clamp and uptake studies using (14)C-labeled urea in AtDUR3-expressing oocytes demonstrated that AtDUR3 mediates urea transport. In both heterologous systems, urea transport was stimulated at low pH. In oocytes, inward currents indicated that urea is cotransported with protons. By contrast, a supply of Na(+) ions could not stimulate urea transport. Transport of (14)C-labeled urea by AtDUR3 in oocytes exhibited saturation kinetics with a K(m) of approximately 3 micro M. AtDUR3 was expressed in shoots and roots and upregulated during early germination and under nitrogen deficiency in roots. We propose a role of AtDUR3 in urea uptake by plant cells at low external urea concentrations.
Dilepton production in proton proton collisions at BEVALAC energies
2003-02-21

The dilepton production in elementary reactions at BEVALAC energies GeV is investigated. The calculations include direct decays of the vector mesons , , and , Dalitz decays of the -, -, -, -, and -mesons, and of the baryon resonances . The subthreshold vector meson production cross sections in collisions are treated in a way sufficient to avoid double counting with the inclusive vector meson production. The vector meson dominance model for the transition form factors of the resonance Dalitz decays is used in an extended form to ensure correct asymptotics which are in agreement with the quark counting rules. Such a modification gives an unified and consistent description of both radiative decays and meson decays. The effect of multiple pion production on the experimental efficiency for the detection of the dilepton pairs is studied. We find the dilepton yield in reasonable agreement with the experimental data for the set of intermediate energies whereas at the highest energy GeV the number of dilepton pairs is likely to be overestimated experimentally in the mass range MeV.
Linear Sweep and Cyclic Voltammetry
2003-02-21

Abstract The sections in this article are Introduction Historical Background Potential Scan Voltammetries—Definitions Scope of the Chapter Theory of Potential Scan Voltammetries General Reversible Electron Transfer Kinetics of Electron Transfer Coupled Homogeneous Chemical Kinetics Adsorption and Surface‐Bound Redox Species Nonlinear Diffusion Restricted Diffusion Simulation Practical Considerations Electrodes and Cells Solvents and Supporting Electrolytes Experimental Limitations Artifacts and how to Avoid Them Present Methodological Developments Voltammetry at Ultramicroelectrodes Fast Scan Techniques Voltammetry without Supporting Electrolyte Voltammetry Under Hydrodynamic Conditions Voltammetric Spectroelectrochemistry Derivative Voltammetry Semiintegral (“Convolution”) and Semiderivative Voltammetry Applications Typical Voltammograms—Classical Applications Selected Recent Examples Conclusion Acknowledgments
Towards Quantum Logic with Cold Atoms in a CO 2 ‐Laser Optical Lattice
2003-02-21

This chapter contains sections titled: Introduction Entanglement and Beyond Quantum Logic and Far-detuned Optical Lattices Resolving and Addressing cold atoms in single lattice sites Recent work References
Resistance Genes of Aminocoumarin Producers: Two Type II Topoisomerase Genes Confer Resistance against Coumermycin A1and Clorobiocin
2003-02-25

ABSTRACT The aminocoumarin resistance genes of the biosynthetic gene clusters of novobiocin, coumermycin A 1 , and clorobiocin were investigated. All three clusters contained a gyrB R resistance gene, coding for a gyrase B subunit. Unexpectedly, the clorobiocin and the coumermycin A 1 clusters were found to contain an additional, similar gene, named parY R . Its predicted gene product showed sequence similarity with the B subunit of type II topoisomerases. Expression of gyrB R and likewise of parY R in Streptomyces lividans TK24 resulted in resistance against novobiocin and coumermycin A 1 , suggesting that both gene products are able to function as aminocoumarin-resistant B subunits of gyrase. Southern hybridization experiments showed that the genome of all three antibiotic producers and of Streptomyces coelicolor contained two additional genes which hybridized with either gyrB R or parY R and which may code for aminocoumarin-sensitive GyrB and ParY proteins. Two putative transporter genes, novA and couR5 , were found in the novobiocin and the coumermycin A 1 cluster, respectively. Expression of these genes in S. lividans TK24 resulted in moderate levels of resistance against novobiocin and coumermycin A 1 , suggesting that these genes may be involved in antibiotic transport.
Short-Course Artesunate Treatment of Uncomplicated Plasmodium falciparum Malaria in Gabon
2003-02-25

ABSTRACT Artesunate is one of the most important antimalarial agents available, since it is effective against parasites that have developed resistance to conventional antimalarials in sub-Saharan Africa. Antimalarial combination chemotherapies with artesunate (4 mg/kg of body weight once daily for 3 days) as one partner have been proposed. However, the efficacy of a 3-day course of artesunate alone has never been evaluated in individuals in Africa (which has 90% of the worldwide malaria burden) living in regions of hyperendemicity, where a considerable degree of immunity might substantially enhance the efficacy of short courses of artesunate compared to those in regions where the levels of endemicity are low. This lack of information does not permit a systematic assessment of the value of artesunate-based combination chemotherapies in Africa. Therefore, we studied the efficacy and safety of a 3-day course of artesunate (4 mg/kg of body weight, orally, once daily) for the treatment of uncomplicated Plasmodium falciparum malaria in Gabonese patients aged 4 to 15 years ( n = 50). Artesunate was well tolerated, and no severe adverse event was reported. Parasite elimination was rapid and was achieved in all patients within ≤72 h (geometric mean time to elimination, 34 h). The PCR-corrected cure rate by day 14 was 92% (46 of 50 patients), but it dropped to 72% (36 of 50 patients) by day 28. We conclude that a 3-day course of artesunate fails to achieve sufficiently high cure rates for uncomplicated falciparum malaria in Gabonese children.
Statins Can Inhibit Proliferation of Human Breast Cancer Cells in Vitro
2003-02-26

The effect of five statins, i.e. atorvastatin, fluvastatin, lovastatin, pravastatin and simvastatin was investigated on the proliferation of the human breast cancer cell line MCF-7. All statins except of pravastatin were able to inhibit cell proliferation up to 90 % at a concentration of 50 micro M. Between the effective statins no significant difference was observed indicating a class-specific effect. These data suggest that statins may have clinical significance in the primary prevention of human breast cancer beyond their cholesterol-lowering effect. However, clinical proof must be awaited before drawing any further conclusions.
Die Kristallstruktur von wasserfreiem Melaminiumchlorid
2003-02-26

Crystal Structure of non‐aqueous Melaminium Chloride Melaminium chloride was obtained as colorless, needle‐shaped, single crystalline material from solid state reactions between melamin and ammonium chloride. The structure of [C 3 N 6 H 7 ]Cl was refined by single crystal X‐ray diffraction: I2/m, Z = 8, a = 852.87(4), b = 1704.4(1) c = 918.44(4) pm and β = 92.165(6)°. The crystal structure contains melaminium ions stacked to columns along [100] and linked via N‐H···N bridges to form bands along [001]. Both of the two distinct chloride ions are stabilized by six hydrogen bonds through distorted trigonal prismatic arrangements of hydrogen atoms to yield a supramolecular structure.
The WSO: a world-class observatory for the ultraviolet
2003-02-26

The World Space Observatory is an unconventional space project proceeding via distributed studies. The present design, verified for feasibilty, consists of a 1.7-meter telescope operating at the second Largangian point of the Earth-Sun system. The focal plane instruments consist of three UV spectrometers covering the spectral band from Lyman alpha to the atmospheric cutoff with R~55,000 and offering long-slit capability over the same band with R~1,000. In addition, a number of UV and optical imagers view adjacent fields to that sampled by the spectrometers. Their performance compares well with that of HST/ACS and the spectral capabilities of WSO rival those of HST/COS.
Optomechanical design of the cosmic hot interstellar plasma spectrometer (CHIPS)
2003-02-26

CHIPS is a NASA UNEX mission designed for diffuse background spectroscopy in the EUV bandpass from 90-260Å. The spectrometer is optimized for peak resolution near 170 Å, in order to study diffuse emissions from cooling million degree plasma. Details of local bubble thermal pressure, spatial distribution, and ionization history are the goals of CHIPS observations. We discuss the opto-mechanical design adopted to meet the throughput, signal to noise, and spectral resolution requirements within the mass, volume, and budgetary constraints of a UNEX Delta-II secondary payload. Mechanical tolerance requirements for the six spectrometer channels are discussed, along with details of the lightweight mounting scheme for CHIPS diffraction gratings, front cover slit mechanisms and thermal design. Finally, visible light and vacuum alignment techniques are discussed, as well as with methods employed to minimize stray light.
Immunocytochemical localization of glycogen phosphorylase isozymes in rat nervous tissues by using isozyme‐specific antibodies
2003-02-28

Abstract Isozyme‐specific antibodies were raised against peptides from the low‐homology regions of the sequences of rat glycogen phosphorylase BB and MM isozymes by immunization of rabbits and guinea pigs. Immunocytochemical double‐labelling experiments on frozen sections of rat nervous tissues were performed to investigate the isozyme localization pattern. Astrocytes throughout the brain and spinal cord expressed both isozymes in perfect co‐localization. Ependymal cells only expressed the BB isozyme. Most neurones were not immunoreactive. The rare neurones that contained glycogen phosphorylase only expressed the BB isozyme. Nearly all of these neurones formed part of the afferent somatosensory system. These findings stress the general importance of glycogen in neural energy metabolism and indicate a special role for the glycogen phosphorylase BB isozyme in neurones in the somatosensory system.
e+ e- ANNIHILATION INTO $\\overline{N}N$ PAIRS
2003-02-28

The reactions of electron-position annihilation into nucleon-antinucleon pairs have been studied in a nonperturbative quark model. The work suggests that the two-step process, in which the primary [Formula: see text] pair forms first a meson and then the meson decays into baryon pair, is dominant over the one-step process in which the primary [Formula: see text] pair is directly dressed by two additional [Formula: see text] pairs to form a baryon pair. The experimental data indicates that there exists a vector meson with quantum numbers I G (J PC ) = 0 - (1 -- ) and a mass around 2 GeV.
NONMESONIC DECAY OF Λ AND ΛΛ HYPERNUCLEI
2003-02-28

Nonmesonic weak decays of single and double hypernuclei are studied on the basis of two-body baryon-baryon interactions, ΛN → NN and ΛΛ → YN transitions. The two-body weak transition is described by the combination of two processes, i.e., meson exchange and direct quark processes. The result indicates the importance of the direct quark(DQ) contribution. It largely enhances both the total decay rate and Γ nn /Γ pn ratio, and its property is different from the heavy meson exchanges (i.e. η, ρ, ω, and K*). The quark-meson hybrid picture, such as π+K+ DQ , reproduces the current experimental data except for the asymmetry parameter for light hypernuclei. The ΛΛ → YN transition in ΛΛ hypernucleus is complement of the ΛN → NN transition because it occurs only in the J = 0 channel which is hidden by J = 1 transition in the ΛN → NN case.
Early Outcome of Carotid Angioplasty and Stenting With and Without Cerebral Protection Devices
2003-03-01

Background— Carotid angioplasty and stenting (CAS) is increasingly being used for treatment of symptomatic and asymptomatic carotid artery disease (CAD). To evaluate the efficacy of cerebral protection devices in preventing thromboembolic complications during CAS, we conducted a systematic review of studies reporting on the incidence of minor stroke, major stroke, or death within 30 days after CAS. Summary of Review— We searched for studies published between January 1990 and June 2002 by means of a PubMed search and a cumulative review of reference lists of all relevant publications. In 2357 patients a total of 2537 CAS procedures had been performed without protection devices, and in 839 patients 896 CAS procedures had been performed with protection devices. Both groups were similar with respect to age, sex distribution, cerebrovascular risk factors, and indications for CAS. In many studies the periprocedural complication rates had not been presented separately for patients with symptomatic and asymptomatic CAD. The combined stroke and death rate within 30 days in both symptomatic and asymptomatic patients was 1.8% in patients treated with cerebral protection devices compared with 5.5% in patients treated without cerebral protection devices (χ 2 =19.7, P &lt;0.001). This effect was mainly due to a decrease in the occurrence of minor strokes (3.7% without cerebral protection versus 0.5% with cerebral protection; χ 2 =22.4, P &lt;0.001) and major strokes (1.1% without cerebral protection versus 0.3% with cerebral protection; χ 2 =4.3, P &lt;0.05), whereas death rates were almost identical (≈0.8%; χ 2 =0.3, P =0.6). Conclusions— On the basis of this early analysis of single-center studies, the use of cerebral protection devices appears to reduce thromboembolic complications during CAS. These technical aspects should be taken into account before the initiation of further randomized trials comparing CAS with carotid endarterectomy.
Enhancing cognitive performance with repetitive transcranial magnetic stimulation at human individual alpha frequency
2003-03-01

Abstract We applied rapid‐rate repetitive transcranial magnetic stimulation (rTMS) at individual alpha frequency (IAF) to improve cognitive performance by influencing the dynamics of alpha desynchronization. Previous research indicates that a large upper alpha power in a reference interval preceding a task is related to both large suppression of upper alpha power during the task and good performance. Here, we tested the hypothesis that rTMS at individual upper alpha frequency (IAF + 1 Hz) can enhance alpha power in the reference interval, and can thus improve task performance. Repetitive TMS was delivered to the mesial frontal (Fz) and right parietal (P6) cortex, and as sham condition with 90°‐tilted coil (P6 position). The behavioural effect was assessed in a mental rotation task. Further control conditions were rTMS at a lower IAF (IAF − 3 Hz) and at 20 Hz. The results indicate that rTMS at IAF + 1 Hz can enhance task performance and, concomitantly, the extent of task‐related alpha desynchronization. This provides further evidence for the functional relevance of oscillatory neuronal activity in the alpha band for the implementation of cognitive performance.
MODFLOW/MT3DMS‐Based Reactive Multicomponent Transport Modeling
2003-03-01

Abstract This paper presents a three‐dimensional, MODFLOW/MT3DMS‐based reactive multicomponent transport model for saturated porous media. Based on a split‐operator technique, the model, referred to as PHT3D, couples the transport simulator MT3DMS and the geochemical modeling code PHREEQC‐2. Through the flexible, generic nature of PHREEQC‐2, PHT3D can handle a broad range of equilibrium and kinetically controlled reactive processes, including aqueous complexation, mineral precipitation/dissolution, and ion exchange. The diversity of potential applications is demonstrated through simulation of five existing literature benchmarks and a new three‐dimensional sample problem. The model might be applied to simulate the geochemical evolution of pristine and contaminated aquifers as well as their cleanup. The latter problem class includes the natural and enhanced attenuation/remediation schemes of a wide range of organic and inorganic contaminants. Processes/reactions not included in the standard PHREEQC‐2 database but typical for this type of application (e.g., NAPL dissolution, microbial growth/decay) can be defined and included via the extensible PHREEQC‐2 database file.
Relationship of Serum Adiponectin and Leptin Concentrations with Body Fat Distribution in Humans
2003-03-01

Abstract Objective : We investigated whether serum concentrations of adiponectin are determined by body fat distribution and compared the findings with leptin. Research Methods and Procedures : Serum concentrations of adiponectin and leptin were measured by radioimmunoassay ( n = 394) and analyzed for correlation with sex, age, and body fat distribution, i.e., waist‐to‐hip ratio, waist and hip circumference, and subcutaneous adipose tissue area of the lower leg as assessed by magnetic resonance imaging. Results : After adjusting for sex and percentage of body fat, adiponectin was negatively ( r = −0.17, p &lt; 0.001) and leptin was positively ( r = 0.22, p &lt; 0.001) correlated with waist‐to‐hip ratio. Leptin, but not adiponectin, correlated with both waist ( r = 0.49, p &lt; 0.001) and hip circumference ( r = 0.46, p &lt; 0.001). Furthermore, leptin, but not adiponectin, correlated with the proportion of subcutaneous fat of the lower leg cross‐sectional area ( r = 0.37, p &lt; 0.001). Discussion : These data suggest that both adipocytokines are associated with central body fat distribution, and serum adiponectin concentrations are determined predominantly by the visceral fat compartment.
Simulation of the development of karst aquifers using a coupled continuum pipe flow model
2003-03-01

This paper is intended to provide insight into the controlling mechanisms of karst genesis based on an advanced modeling approach covering the characteristic hydraulics in karst systems, the dissolution kinetics, and the associated temporal decrease in flow resistance. Karst water hydraulics is strongly governed by the interaction between a highly conductive low storage conduit network and a low‐conductive high‐storage rock matrix under variable boundary conditions. Only if this coupling of flow mechanisms is considered can an appropriate representation of other relevant processes be achieved, e.g., carbonate dissolution, transport of dissolved solids, and limited groundwater recharge. Here a parameter study performed with the numerical model Carbonate Aquifer Void Evolution (CAVE) is presented, which allows the simulation of the genesis of karst aquifers during geologic time periods. CAVE integrates several important features relevant for different scenarios of karst evolution: (1) the complex hydraulic interplay between flow in the karst conduits and in the small fissures of the rock matrix, (2) laminar as well as turbulent flow conditions, (3) time‐dependent and nonuniform recharge to both flow systems, (4) the widening of the conduits accounting for appropriate physicochemical relationships governing calcite dissolution kinetics. This is achieved by predefining an initial network of karst conduits (“protoconduits”) which are allowed to grow according to the amount of aggressive water available due to hydraulic boundary conditions. The increase in conduit transmissivity is associated with an increase in conduit diameters while the conductivity of the fissured system is assumed to be constant in time. The importance of various parameters controlling karst genesis is demonstrated in a parameter study covering the recharge distribution, the upgradient boundary conditions for the conduit system, and the hydraulic coupling between the conduit network and the rock matrix. In particular, it is shown that conduit diameters increase in downgradient or upgradient direction depending on the spatial distribution (local versus uniform) of the recharge component which directly enters the conduit system.