julilili42/papers huggingface dataset:
Discovery of photospheric argon in very hot central stars of planetary nebulae and white dwarfs
2007-02-20

\\n Context.We report the first discovery of argon in hot evolved stars and white\\n dwarfs. We have identified the 1063.55 Å line in some of the\\n hottest known ( = 95 000-110 000 K) central stars of planetary nebulae\\n and (pre-) white dwarfs of various spectral type.\\n Aims.We determine the argon abundance and compare it to theoretical predictions from\\n stellar evolution theory as well as from diffusion calculations.\\n Methods.We analyze high-resolution spectra taken with the Far Ultraviolet\\n Spectroscopic Explorer. We use non-LTE line-blanketed model atmospheres and\\n perform line-formation calculations to compute synthetic argon line profiles.\\n Results.We find a solar argon abundance in the H-rich central star NGC 1360 and in the\\n H-deficient PG 1159 star PG 1424+535. This confirms stellar evolution modeling\\n that predicts that the argon abundance remains almost unaffected by\\n nucleosynthesis. For the DAO-type central star NGC 7293 and the hot DA white\\n dwarfs PG 0948+534 and RE J1738+669 we find argon abundances that are up to\\n three \\n orders of magnitude smaller than predictions of calculations assuming\\n equilibrium of radiative levitation and gravitational settling. For the hot DO\\n white dwarf PG 1034+001 the theoretical overprediction amounts to one dex.\\n Conclusions.Our results confirm predictions from stellar nucleosynthesis calculations for\\n the argon abundance in AGB stars. The argon abundance found in hot white\\n dwarfs, however, is another drastic example that the current state of\\n equilibrium theory for trace elements fails to explain the observations\\n quantitatively.\\n
Expression of the CUB domain containing protein 1 (CDCP1) gene in colorectal tumour cells
2007-02-20

Expression of CUB domain containing protein 1 (CDCP1) is upregulated in carcinoma cells. We quantitated CDCP1 gene expression in matched normal colon and tumour tissue and compared the level of expression to other genes upregulated in colorectal tumourigenesis. Furthermore, we show that the CDCP1 gene generates two transcripts which are co‐expressed in normal and matched tumour tissue as well as in the majority of cell lines analysed. However, intracellular localisation studies revealed that only one of these transcripts encodes a protein that is localised to the cell surface.
Importance of Compton scattering for radiation spectra of isolated neutron stars with weak magnetic fields
2007-02-20

Emergent model spectra of neutron star atmospheres are widely used to fit the observed soft X-ray spectra of different types of isolated neutron stars. We investigate the effect of Compton scattering on the emergent spectra of hot (T_eff > 10^6 K) isolated neutron stars with weak magnetic fields. In order to compute model atmospheres in hydrostatic and radiative equilibrium we solve the radiation transfer equation with the Kompaneets operator. We calculate a set of models with effective temperatures in the range 1 - 5 * 10^6 K, with two values of surface gravity (log g = 13.9 and 14.3) and different chemical compositions. Radiation spectra computed with Compton scattering are softer than those computed without Compton scattering at high energies (E > 5 keV) for light elements (H or He) model atmospheres. The Compton effect is more significant in H model atmospheres and models with low surface gravity. The emergent spectra of the hottest (T_eff > 3 * 10^6 K) model atmospheres can be described by diluted blackbody spectra with hardness factors ~ 1.6 - 1.9. Compton scattering is less important in models with solar abundance of heavy elements.
Importance of Compton scattering for radiation \\nspectra of isolated neutron stars with weak magnetic fields
2007-02-20

\\n Aims.Emergent model spectra of neutron-star atmospheres are widely used to\\nfit the observed soft X-ray spectra of different types of isolated neutron\\nstars. We investigate the effect of Compton scattering on the emergent spectra\\nof hot ( K) isolated neutron stars with weak magnetic\\nfields.\\n Methods.In order to compute model atmospheres in hydrostatic and radiative\\nequilibrium we solve the radiation transfer equation with the Kompaneets\\noperator. We calculate a set\\nof models with effective temperatures in the range 1–5 106 K, with\\ntwo values of surface gravity ( = 13.9 and 14.3) and different\\nchemical compositions.\\n Results.Radiation spectra computed with Compton scattering are softer than those\\ncomputed without Compton scattering at high energies ( 5 keV) for light-element\\n(H or He) model atmospheres. The Compton effect is more significant in H model atmospheres and models with low surface gravity. The emergent\\nspectra of the hottest (Teff &gt;3 106 K) model atmospheres can be\\ndescribed by diluted blackbody spectra with hardness factors ~1.6–1.9.\\nCompton scattering is less important in models with solar abundance of heavy\\nelements.\\n
Search for pulsed VHE gamma-ray emission from young pulsars with HESS
2007-02-20

Aims. We present the results of a search for pulsed very-high-energy (VHE) γ-ray emission from young pulsars using data taken with the HESS imaging atmospheric Cherenkov telescope system. Methods. Data on eleven pulsars, selected according to their spin-down luminosity relative to distance, are searched for γ-ray signals with periodicity at the respective pulsar spin period. Special analysis efforts were made to improve the sensitivity in the 100 GeV γ-ray energy domain in an attempt to reduce the gap between satellite and ground-based γ-ray instruments. Results. No significant evidence for pulsed emission is found in any data set. Differential upper limits on pulsed energy flux are determined for all selected pulsars in the approximate γ-ray energy range between 100 GeV and 50 TeV, using different limit determination methods, testing a wide range of possible pulsar light curves and energy spectra. Conclusions. The limits derived here imply that the magnetospheric VHE γ-ray production efficiency in young pulsars is less than 10−4 of the pulsar spin-down luminosity, requiring spectral turnovers for the high-energy emission of four established γ-ray pulsars, and constrain the inverse Compton radiation component predicted by several outer gap models.
LACHESIS Restricts Gametic Cell Fate in the Female Gametophyte of Arabidopsis
2007-02-21

In flowering plants, the egg and sperm cells form within haploid gametophytes. The female gametophyte of Arabidopsis consists of two gametic cells, the egg cell and the central cell, which are flanked by five accessory cells. Both gametic and accessory cells are vital for fertilization; however, the mechanisms that underlie the formation of accessory versus gametic cell fate are unknown. In a screen for regulators of egg cell fate, we isolated the lachesis (lis) mutant which forms supernumerary egg cells. In lis mutants, accessory cells differentiate gametic cell fate, indicating that LIS is involved in a mechanism that prevents accessory cells from adopting gametic cell fate. The temporal and spatial pattern of LIS expression suggests that this mechanism is generated in gametic cells. LIS is homologous to the yeast splicing factor PRP4, indicating that components of the splice apparatus participate in cell fate decisions.
(1aR,2aS,5aS,5bS)-Perhydro-4H-oxireno[3,4]cyclopenta[1,2-b]furan-4-one
2007-02-21

The structure of the title compound, C 7 H 8 O 3 , was determined in the course of our studies of the synthesis of cyclopenta[1,2- b ]furan-4-one derivatives. The molecule has four chiral C atoms. The X-ray crystal structure analysis shows the compound to possess an epoxide group with an endo orientation with respect to the lactone group.
First ground-based measurement of atmospheric Cherenkov light from cosmic rays
2007-02-22

A recently proposed novel technique for the detection of cosmic rays with arrays of Imaging Atmospheric Cherenkov Telescopes is applied to data from the High Energy Stereoscopic System (H.E.S.S.). The method relies on the ground-based detection of Cherenkov light emitted from the primary particle prior to its first interaction in the atmosphere. The charge of the primary particle (Z) can be estimated from the intensity of this light, since it is proportional to Z2. Using H.E.S.S. data, an energy spectrum for cosmic-ray iron nuclei in the energy range 13–200 TeV is derived. The reconstructed spectrum is consistent with previous direct measurements and is one of the most precise so far in this energy range.
Eigenmode frequency distribution of rapidly rotating neutron stars
2007-02-23

We use perturbation theory and the relativistic Cowling approximation to numerically compute characteristic oscillation modes of rapidly rotating relativistic stars which consist of a perfect fluid obeying a polytropic equation of state. We find the expected infinite pressure mode spectrum extending towards higher frequencies, but also what appears to be an infinite number of inertial modes confined to a finite, well-defined frequency range, depending on the compactness and the rotation frequency of the star. We observe the shift of this range towards negative frequencies for non-axisymmetric modes with respect to the axisymmetric ones, making all m&gt;2 modes unstable. We discuss whether our results indicate the existence of a continuous part of the star's spectrum, or whether they all are discrete solutions.
4-[5-(4-Fluorophenyl)-3-isopropylisoxazol-4-yl]pyridin-2(1H)-one
2007-02-23

The crystal structure of the title compound, C 17 H 15 FN 2 O 2 , was determined as part of a study of the biological activity of pyridine-substituted isoxazole derivatives as mitogen-activated protein kinase (MAPK) inhibitors. In the crystal structure of the title compound, the compound exists in the lactam and not in the tautomeric pyridin-2-ol form. As the aromatic pyridine nitrogen is considered to be important for accepting a hydrogen bond from p38MAPK, the structure of the lactam unit is correlated with the loss of biological activity of the title compound in the p38MAPK assay. In the crystal structure, the lactam is involved in hydrogen bonds, forming chains along the b axis.
Ethyl (2,3-dihydro-1H,1′H-2,3′-biindol-1-yl)glyoxylate
2007-02-23

The crystal structure of the title compound, C 20 H 18 N 2 O 3 , was determined in the course of our studies of the synthesis of 3-acylindole derivatives. We obtained it as an unexpected racemic side product. The crystal structure contains chains of dimers along the a axis.
Hyphenation of Gas Chromatography to Microcoil 1H Nuclear Magnetic Resonance Spectroscopy
2007-02-24

Whereas the hyphenation of gas chromatography (GC) with mass spectrometry is of great importance, little is known about the coupling to nuclear magnetic resonance spectroscopy (NMR). The investigation of this technique is an attractive proposition because of the valuable information given by NMR on molecular structure. The experiments shown here are to our knowledge the first hyphenating capillary GC to microcoil NMR. In contrast to liquids, gases have rarely been investigated by NMR, mainly due to the experimental difficulties in handling gases and the low signal-to-noise-ratio (SNR) of the NMR signal obtained at atmospheric pressure. With advances in NMR sensitivity (higher magnetic fields and solenoidal microprobes), this limitation can be largely overcome. In this paper, we describe the use of a custom-built solenoidal NMR microprobe with an active volume of 2 microL for the NMR detection of several compounds at 400 MHz, first in a mixture, and then with full coupling to capillary GC to identify them separately. The injected amounts of each analyte in the hyphenated experiments are in the range of 15-50 micromol, resulting in reasonable SNR for sample masses of 1-2 microg.
Safety and pharmacokinetics of bivatuzumab mertansine in patients with CD44v6-positive metastatic breast cancer: final results of a phase I study
2007-02-26

The purpose of this study was to investigate the safety, pharmacokinetics and preliminary efficacy of bivatuzumab mertansine in patients with CD44v6-positive metastatic breast cancer. Anthracycline and taxane-pretreated patients with metastatic breast cancer that expressed CD44v6 received one single infusion of bivatuzumab mertansine and were observed for 21 days within one treatment course. Starting dose was 25 mg/m, while dose was escalated by increments of 25 mg/m. Patients who experienced a disease stabilization were eligible for further courses with bivatuzumab mertansine. Blood serum samples were taken throughout the treatment period for pharmacokinetic analysis. Twenty-four patients were treated at eight different dose levels (25-200 mg/m), seven of these patients received more than one course of bivatuzumab mertansine. Two dose-limiting toxicities occurred: one patient treated with 125 mg/m developed transient National Cancer Institute Common Toxicity Criteria grade 4 elevation of liver enzymes; another patient treated at 175 mg/m experienced National Cancer Institute Common Toxicity Criteria grade 3 vomiting. She died from renal failure, which might have been caused by deterioration of pre-existing renal insufficiency. The most common toxicities were transient and mild skin disorders in 75% of patients. As a consequence of one fatal toxic epidermal necrolysis that occurred in a study running in parallel, the clinical trials programme of bivatuzumab mertansine was discontinued. None of the patients developed antibodies against bivatuzumab mertansine. No objective responses were observed. Disease stabilization was achieved in 50% of patients independently of dose level. In conclusion, bivatuzumab mertansine targets CD44v6 and appears to stabilize heavily pretreated metastatic breast cancer that expresses CD44v6. The maximum tolerated dose could not be determined in this trial as the sponsor discontinued the clinical development of bivatuzumab mertansine.
Propagator Dyson-Schwinger equations of Coulomb gauge Yang-Mills theory within the first order formalism
2007-02-26

Coulomb gauge Yang-Mills theory within the first order formalism is considered with a view to deriving the propagator Dyson-Schwinger equations. The first order formalism is studied with special emphasis on the BRS invariance and it is found that there exists two forms of invariance - invariance under the standard BRS transform and under a second, non-standard transform. The field equations of motion and symmetries are derived explicitly and certain exact relations that simplify the formalism are presented. It is shown that the Ward-Takahashi identity arising from invariance under the non-standard part of the BRS transform is guaranteed by the functional equations of motion. The Feynman rules and the general decomposition of the two-point Green's functions are derived. The propagator Dyson-Schwinger equations are derived and certain aspects (energy independence of ghost Green's functions and the cancellation of energy divergences) are discussed.
PRECLINICAL STUDY: The effects of p‐chloroamphetamine, methamphetamine and 3,4‐methylenedioxymethamphetamine (ecstasy) on the gene expression of cytoskeletal proteins in the rat brain
2007-02-26

ABSTRACT Repeated administration of β‐phenylalkylamines is known to produce neuronal changes in the central and peripheral nervous systems of mammals. It is suggested that various components of the cytoskeleton undergo profound alterations after amphetamine use and misuse, contributing to behavioral changes and neurotoxicity. Here we studied the expression of microtubule‐associated protein 2 (MAP2) and β‐actin after repeated intraperitoneal applications with equimolar doses of p‐chloroamphetamine (PCA), methamphetamine (METH) and 3,4‐methylenedioxymethamphetamine (MDMA) in the brain of male Wistar rats. Effective (molecular) pharmacological doses (ED) were derived and used for the calculation of (molecular) pharmacological indices (PI). Besides clear but different dose–response curves on the toxicity of the drugs, in situ hybridization and Western blot analysis revealed that repeated administration of these compounds resulted in different substance‐ and dose‐dependent changes in MAP2 gene expression, e.g. in the frontoparietal somatosensoric cortex. In contrast, the expression of β‐actin was not influenced by any of the compounds at the dose levels tested. Lethal doses were determined with 2.1 (PCA), &gt;5.1 (METH) and 8.4 mg/kg/day (MDMA). Linear and non‐linear repeat‐dose lethality was observed for MDMA and PCA, respectively, whereas METH was non‐lethal in the dose range used. Values for ED MAP2 were 0.3, 0.52 and &gt;16.8 mg/kg/day, and therefore those for PI MAP2 were 20, 4, and 0.5 for METH, PCA and MDMA, respectively. Although the results on mortality did not reflect changes in MAP2 gene expression, they suggest a remarkable difference for those amphetamines without substituents or with a halogen atom at the paraposition of the benzene ring, such as METH or PCA, when compared with MDMA‐like substances.
BIOMARKER: The validity of the laboratory marker combinations DOVER and QUVER to detect physician’s diagnosis of at‐risk drinking
2007-02-26

ABSTRACT Especially in situations where it might be favorable for the patient to dissimulate the existing alcohol problem, ‘objective’ laboratory tests can be helpful. In this study we report validation of the two combinations DOVER (DOctor VERified) and QUVER (QUestionnarie VERified) of the biological markers percent carbohydrate‐deficient transferrin (%CDT) and gamma‐glutamyl‐transferase (γ‐GT) to detect patients that have been identified by their physicians with at‐risk drinking behavior. Fifty‐eight general practitioners (GPs) participated at two study sites in South‐West Germany. Patients filled in a questionnaire that included the alcohol use disorders identification test (AUDIT) and gave a blood sample. The GP recorded his/her assessment about the presence of an alcohol‐related disorder in the patient. Receiver operating characteristics (ROC) analyses of the marker combinations DOVER and QUVER were performed. A total of 2940 patients participated in the study, of which 2496 completed data sets that could be used for further analysis. The area under the curve (AUC) of 79.5% for DOVER and 77.2% (QUVER) are in a higher range than the values for gamma%CDT (75.7%) or γ‐GT (72.5%) and %CDT (64.5%) and suggest superiority of the proposed marker combinations. Cross‐validation results were almost identical with 76.6% and 73.3% for DOVER and QUVER, respectively. Our analysis demonstrated that the combination of the markers γ‐GT and %CDT with the physician’s judgement of the condition as reference was superior to the use of single markers.
2007-02-26

Ancient Hindu Ayurvedic texts described the use of extracts from Coleus species.An isolated diterpene from Coleus forskohlii, called forskolin, was demonstrated to be a hypotensive agent with spasmolytic, cardiotonic and platelet aggregation inhibitory activity.It has been shown to be a powerful activator of the enzyme adenylate cyclase in various tissues.Forskolin is thought to act on the catalytic subunit and also on the coupling mechanism of guanine regulatory sites (Ns and Ni) with the catalytic subunit.It is now clear that forskolin elicits physiological responses which have been shown to be cAMP-dependent.
An Accurate Risk Score Based on Anthropometric, Dietary, and Lifestyle Factors to Predict the Development of Type 2 Diabetes
2007-02-27

OBJECTIVE—We aimed to develop a precise risk score for the screening of large populations for individuals at high risk of developing type 2 diabetes based on noninvasive measurements of major risk factors in German study populations. RESEARCH DESIGN AND METHODS—A prospective cohort study (European Prospective Investigation into Cancer and Nutrition [EPIC]-Potsdam study) of 9,729 men and 15,438 women aged 35–65 years was used to derive a risk score predicting incident type 2 diabetes. Multivariate Cox regression model coefficients were used to weigh each variable in the calculation of the score. Data from the EPIC-Heidelberg, the Tübingen Family Study for Type 2 Diabetes (TÜF), and the Metabolic Syndrome Berlin Potsdam (MeSyBePo) study were used to validate this score. RESULTS—Information on age, waist circumference, height, history of hypertension, physical activity, smoking, and consumption of red meat, whole-grain bread, coffee, and alcohol formed the German Diabetes Risk Score (mean 446 points [range 118–983]). The probability of developing diabetes within 5 years in the EPIC-Potsdam study increased from 0.3% for 300 to 23.2% for 750 score points. The area under the receiver-operator characteristic (ROC) curve was 0.84 in the EPIC-Potsdam and 0.82 in the EPIC-Heidelberg studies. Correlation coefficients between the German Diabetes Risk Score and insulin sensitivity in nondiabetic individuals were −0.56 in the TÜF and −0.45 in the MeSyBePo studies. ROC values for undiagnosed diabetes were 0.83 in the TÜF and 0.75 in the MeSyBePo studies. CONCLUSIONS—The German Diabetes Risk Score (available at www.dife.de) is an accurate tool to identify individuals at high risk for or with undiagnosed type 2 diabetes.
Randomized Controlled Trial of Fosmidomycin-Clindamycin versus Sulfadoxine-Pyrimethamine in the Treatment of Plasmodium falciparum Malaria
2007-02-27

ABSTRACT Fosmidomycin-clindamycin therapy given every 12 h for 3 days was compared with a standard single oral dose of sulfadoxine-pyrimethamine. The two treatments showed comparably good tolerabilities and had an identical high degree of efficacy of 94% in a randomized trial carried out with 105 Gabonese children aged 3 to 14 years with uncomplicated malaria. These antimalarials merit further clinical exploration.
The proteasomal subunit S6 ATPase is a novel synphilin‐1 interacting protein—implications for Parkinson's disease
2007-02-27

ABSTRACT Synphilin‐1 is linked to Parkinson's disease (PD), based on its role as an alpha‐synuclein (PARK1)‐interacting protein and substrate of the ubiquitin E3 ligase Parkin (PARK2) and because of its presence in Lewy bodies (LB) in brains of PD patients. We found that overexpression of synphilin‐1 in cells leads to the formation of ubiquitinated cytoplasmic inclusions supporting a derangement of the ubiquitin‐proteasome system in PD. We report here a novel specific interaction of synphilin‐1 with the regulatory proteasomal protein S6 ATPase (tbp7). Functional characterization of this interaction on a cellular level revealed colocalization of S6 and synphilin‐1 in aggresome‐like intracytoplasmic inclusions. Overexpression of synphilin‐1 and S6 in cells caused reduced proteasomal activity associated with a significant increase in inclusion formation compared to cells expressing syn‐philin‐1 alone. Steady‐state levels of synphilin‐1 in cells were not altered after cotransfection of S6 and colocal‐ization of synphilin‐1‐positive inclusions with lysosomal markers suggests the presence of an alternative lysosomal degradation pathway. Subsequent immunohistochemical studies in brains of PD patients identified S6 ATPase as a component of LB. This is the first study investigating the physiological role of synphilin‐1 in the ubiquitin protea‐some system. Our data suggest a direct interaction of synphilin‐1 with the regulatory complex of the protea‐some modulating proteasomal function.—Marx F. P., Soehn, A. S., Berg, D., Melle, C., Schiesling, C., Lang, M., Kautzmann, S., Strauss, K. M., Franck, T., Engelender, S., Pahnke, J., Dawson, S., von Eggeling F., Schulz, J. B., Riess, O., Krüger R. The proteasomal subunit S6 ATPase is a novel synphilin‐1 interacting protein—implications for Parkinson's disease. FASEB J. 21, 1759–1767 (2007)