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W Rau

Publications and source records attributed to W Rau.

At least 19 recordsLinked to original sources
PubMed2006

Limits on spin-independent interactions of weakly interacting massive particles with nucleons from the two-tower run of the cryogenic dark matter search.

We report new results from the Cryogenic Dark Matter Search (CDMS II) at the Soudan Underground Laboratory. Two towers, each consisting of six detectors, were operated for 74.5 live days, giving spectrum-weighted exposures of 34 (12) kg d for the Ge (Si) targets after cuts, averaged over recoil energies 10-100 keV for a weakly interacting massive particle (WIMP) mass of 60 GeV/c2. A blind analysis was conducted, incorporating improved techniques for rejecting surface events. No WIMP signal exceeding expected backgrounds was observed. When combined with our previous results from Soudan, the 90% C.L. upper limit on the spin-independent WIMP-nucleon cross section is 1.6 x 10(-43) cm2 from Ge and 3 x 10(-42) cm2 from Si, for a WIMP mass of 60 GeV/c2. The combined limit from Ge (Si) is a factor of 2.5 (10) lower than our previous results and constrains predictions of supersymmetric models.

Journal Article↗
PubMed2004

First results from the Cryogenic Dark Matter Search in the Soudan Underground Laboratory.

We report the first results from a search for weakly interacting massive particles (WIMPs) in the Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory. Four Ge and two Si detectors were operated for 52.6 live days, providing 19.4 kg d of Ge net exposure after cuts for recoil energies between 10 and 100 keV. A blind analysis was performed using only calibration data to define the energy threshold and selection criteria for nuclear-recoil candidates. Using the standard dark-matter halo and nuclear-physics WIMP model, these data set the world's lowest exclusion limits on the coherent WIMP-nucleon scalar cross section for all WIMP masses above 15 GeV/c2, ruling out a significant range of neutralino supersymmetric models. The minimum of this limit curve at the 90% C.L. is 4 x 10(-43) cm2 at a WIMP mass of 60 GeV/c2.

Journal Article↗
PubMed2004

Disseminated periportal fatty degeneration after allogeneic intraportal islet transplantation in a patient with type 1 diabetes mellitus: a case report.

Insulin independence after islet transplantation has been significantly improved by using new steroid-free immunosuppressive protocols and increased islet mass. Only little is known about the influence on the morphology of the liver of intraportally transplanted islets. We describe a case of disseminated periportal fatty degeneration after allogeneic intraportal islet transplantation (ITx). A 35-year-old patient with type-1 diabetes mellitus who was suffering from repeated severe hypoglycemic episodes received two sequential intraportal islet grafts. Liver structure was normal before the first ITx, based upon ultrasound and magnetic resonance imaging (MRI). One week after the first ITx, ultrasound demonstrated normal liver morphology. Four months later, at the second ITx, we detected small, disseminated, and hypodense hepatic lesions (1 to 3 mm) by ultrasound, which were confirmed by MRI and interpreted to be fatty degenerations. Histologically we found focal drop-shaped fatty degenerations with signs of mild periportal chronic inflammation. These liver alterations without clinical symptoms or pathological liver function tests matched the predicted distribution of infused islets. Glucose metabolism markedly improved after the first ITx, namely 58.6% reduction of daily insulin requirements, 1.4% decrease in HbA1c, basal C-peptide of 0.8 to 1.3 ng/dl with no severe hypoglycemia. We interpreted these benign changes in liver morphology as reactions to a local hyperinsulinemia in the neighborhood of the transplanted islets. We hypothesized that a steroid-free immunosuppression with rapamycin and tacrolimus may have contributed to changes in the portal microenvironment.

Adult↗
PubMed2000

222Rn emanation measurements at extremely low activities

For the solar neutrino experiment Borexino, a system has been set up to measure emanation of 222Rn in samples of up to 80 litres volume. The apparatus has been constructed to high vacuum standard and consists mainly of parts made from electropolished stainless steel. The low blank activity of the system together with a highly sensitive detection method for the extracted Rn leads to a sensitivity level in the range 70-100 microBq 222Rn. Due to the large sample capacity of the emanation chambers, it is possible to measure specific emanation rates as low as several microBq/m2. Some measurements characterizing the performance of the apparatus are discussed.

Journal Article↗
PubMed2000

222Rn detection at the microBq/m3 range in nitrogen gas and a new Rn purification technique for liquid nitrogen

For the Borexino solar neutrino experiment a concentration line for 222Rn from a large volume of nitrogen gas has been constructed. It is based on cryo-adsorption in a charcoal trap of very low intrinsic 226Ra contamination. Consequently, the blank for activity from the daughter nuclide 222Rn is very low. 222Rn is recorded with proportional counters. This allows the detection of Rn at concentrations below the microBq/m3 level in gaseous nitrogen. The removal of radon from liquid nitrogen is achieved by direct adsorption in the liquid phase. 222Rn-measurements on evaporated nitrogen with and without previous purification are reported.

Journal Article↗
PubMed1999

Rational diagnostic steps in acute pyelonephritis with special reference to ultrasonography and computed tomography scan.

Depending on the severity of the clinical syndrome, acute pyelonephritis may require more extensive imaging diagnostics. In the uncomplicated form of the disease, ultrasonography does not appear to be absolutely necessary. In clinically severe cases, however, which fail to respond to antibiotic therapy, ultrasound is the optimal procedure for ruling out urinary tract obstruction. Where there is clinical suspicion of complications proven risk factors, persistent fever and/or continuing pathological inflammation parameters (elevated C-reactive protein levels in serum)-ultrasonography is the primary imaging technique for the exclusion of pyonephrosis, as well as for other complicating factors such as calculi, etc. In cases of insufficient response to antibiotic therapy, we recommend performing a renal computed tomography scan with contrast medium, in order to rule out hypoenhancing zones as hints for severe tissue alterations. This procedure is in accordance with the suggestions of the Society for Uroradiology. In the future, DMSA scintigraphy might constitute an equivalent diagnostic method for the exclusion of these focal inflammatory changes. Above all, DMSA scintigraphy makes it possible to anticipate the development of scars following acute pyelonephritis.

Acute Disease↗
PubMed1998

Sex determination in Ellobius lutescens: the story of an enigma.

The unusual karyotype of Ellobius lutescens (2n = 17,X in males and females) has attracted permanent interest and prompted a series of hypotheses on sex determination in this species since its first description by Matthey (1953). The developing knowledge about the sex chromosomes and sex determination as well as the availability of new cytogenetic and molecular genetic techniques prompted studies to test the compatibility between current hypotheses and new findings and rendered modifications of the hypotheses necessary. After a long period dominated by the question what the sex chromosome constitution of this species might be and where the testis determining factor could be located, the presence of Sry had been eventually excluded and sex determination attributed to a hypothetical mutated gene acting downstream of Sry. An X-chromosomal or autosomal location of this gene can be assessed by cosegregation of sex with X-chromosome markers. Some preliminary results concerning X-chromosome dinucleotide repeat markers are reported. However, these markers were homomorphic in Ellobius lutescens. We now report evidence that Zfy is also missing in Ellobius lutescens and E. tancrei (males and females XX), a finding from which we conclude that the entire Y chromosome has been lost from these species. Perspectives concerning future studies are discussed.

Animals↗
PubMed1992

Disappearance of a pituitary tumor after 15 months of treatment with CV 205-502, a new dopamine agonist.

We report the case of a 27-year-old woman with a prolactin-secreting macroadenoma of the pituitary gland who was under treatment with a new dopamine agonist, Sandoz CV 205-502. Immediately after diagnosis of a 12 x 10 mm intrasellar prolactinoma, treatment with CV 205-502 was begun at a daily dose of 0.075 mg. Under this low dose, prolactin in the serum normalized after 4 weeks, the initial hormone value being 189.9 ng/ml. After 6 months of therapy there was still a 6 x 6 mm tumor, and after 15 months of treatment the pathological process could no longer be observed with magnetic resonance imaging. In the 20th month of therapy the patient became pregnant. An ovulatory menstrual cycle had been present for a few months.

Adult↗
PubMed1992

Differences in the radiotoxicity of two plutonium isotopes in cells in vitro: can they be ascribed to different handling by the cells?

Exposure of Co631 cells to plutonium leads to increasing cell death depending on the dose and incubation time. The effects, however, are more pronounced with 239Pu, than with 238Pu. Uptake and binding of the two radionuclides during a 5-h incubation are about equal, but 238Pu is lost more rapidly from the cell. There are also differences in the subcellular distribution which lead to a pronounced difference in the distribution of radioactivity. The influence of these differences in the handling of 238Pu and 239Pu by the cell and of the mass difference on the radiotoxicity of the radionuclides is discussed.

Animals↗
PubMed1990

Comparison of the binding of 59Fe- and 239Pu-transferrin to rat liver cell membranes.

The binding of the 59Fe and 239Pu complexes of transferrin and 125I labelled transferrin [Tf (125I)] to isolated cell membranes of rat liver has been studied. Transferrin forms a complex with an integral protein of the membrane which has an apparent molecular weight of about 180 kDa and is stable only at pH 7.4. Iron-59 is eluted from Sephacryl S 300 columns together with Tf (125I) or the Tf-membrane protein complex while 239Pu seems to be bound to different membrane protein(s). After isolation of the Tf-binding protein from 35S-labelled membranes and incubation with one of the metal-Tf complexes 59Fe elutes from a Sephacryl S 300 column together with 35S at an apparent molecular weight of ca. 250 kDa while 239Pu is found in fractions of lower molecular weight. It is concluded from these results that there are Tf-receptors in the liver cell membrane to which iron transferrin may bind. Plutonium, however, seems to be dissociated from Tf and bound directly to other membrane proteins.

Animals↗
PubMed1989

Effects of continuous exposure to 239Pu-alpha rays on Co631 cells.

Exposure of Co631 cells to 239Pu-citrate leads to continuous irradiation and results in increasing cell death which depends on dose and incubation time of the metal. The D37 is calculated to be 0.13 Gy. Plutonium-239 induces the amplification of the integrated SV40 sequences of the Co631 cells. Other cellular genes such as the alpha-actin gene were not amplified, indicating that the SV40-gene amplification is a selective process. Southern blot analysis of genomic DNA shows that not all S40 sequences are equally amplified. Excised sequences of the SV40 genome only appear after an exposure time of 4 days.

Animals↗
PubMed1989

Two models for screening chelating agents for cadmium removal.

The effectiveness of some chelating agents to mobilize cadmium from Chinese hamster ovary cells after chronic exposure (20 hr), as well as from cytosolic metallothionein, was studied. In the first protocol, the most effective substance was 2,3-dimercaptopropanol, followed by 2,3-dimercaptopropane-1-sulfonate and 2,3-dimercaptosuccinic acid, whereas CaNa3-diethylenetriamine pentaacetic acid X 5 H2O showed less effect. Simultaneous incubation of cells with cadmium and the chelating agent resulted in a different order of effectiveness: CaNa3 DTPA prevented cadmium uptake almost totally, 2,3-mercaptopropanol by 75% and 2,3-dimercaptopropane-1-sulfonate by 35%. Neither CaNa3-diethylenetriamine pentaacetic acid X 5 H2O nor 2,3-dimercaptosuccinic acid had altered the distribution of cadmium between the cytosolic protein fractions after a 2 hr incubation of cells, whereas after this period, 2,3-dimercaptopropanol had removed all cadmium from metallothionein, and 2,3-dimercaptopropane-1-sulfonate about 50%. None of the chelating agents had reduced the amount of Cd bound to high molecular weight proteins. In the cell-free system, 2,3-dimercaptopropanol and 2,3-dimercaptopropane-1-sulfonate were equally effective and removed all cadmium from metallothionein within ten minutes. CaNa3-diethylenetriamine pentaacetic acid X 5 H2O, however, even after 60 min, had removed only 50% of the cadmium. The remaining cadmium was found distributed to the high molecular weight and lower molecular weight protein fractions.

Animals↗
PubMed1987

[Stomach ulcer as a problem of energy balance: design of a cellular automatic simulation of disorders of blood flow distribution in the stomach wall].

A cellular automaton is described, which allows a simple simulation of patterns of gastric blood flow distribution. Effects of redistribution, which can be simulated on the basis of the energy requirements of acid secretion and the morphology of the gastric vascular bed, are isomorph to form and site of gastric ulcer in man. Special forms of the 'peptic' lesion as linear ulcers or 'peptic' stenoses of the oesophagus are consistent with the theory of a submucous steal-phenomenon.

Algorithms↗