Atomic structure of interface states in silicon heterojunction solar cells.

Combining orientation dependent electrically detected magnetic resonance and g tensor calculations based on density functional theory we assign microscopic structures to paramagnetic states involved in spin-dependent recombination at the interface of hydrogenated amorphous silicon crystalline silicon (a-Si:H/c-Si) heterojunction solar cells. We find that (i) the interface exhibits microscopic roughness, (ii) the electronic structure of the interface defects is mainly determined by c-Si, (iii) we identify the microscopic origin of the conduction band tail state in the a-Si:H layer, and (iv) present a detailed recombination mechanism.

Equivalence of spray-dried K2EDTA, spray-dried K3EDTA, and liquid K3EDTA anticoagulated blood samples for routine blood center or transfusion service testing.

We compared the results of routine blood tests for 102 blood donors' samples and 100 patients' samples collected in spray-dried K2EDTA, spray-dried K3EDTA, and liquid K3EDTA blood collection tubes to evaluate the impact of changes in formulation of the anticoagulant (K2EDTA vs.K3EDTA), its application (liquid vs. spray-dried), and tube material (glass vs. plastic). Methods for ABO/D testing, antibody screening, and antibody identification included direct hemagglutination/microplate (Olympus(R) PK 7200) and gel column methods (Ortho ID-Micro Typing System/Gel Test). Additional studies on blood donors' samples included time delayed antigen testing and antibody identification and half-draw/half-evacuated collections. Also, we compared the results of routine ABO/D testing and antibody screening for 50 patients' samples collected in spray-dried K2EDTA and spray-dried K3EDTA and for an additional 50 patients' samples collected in spray-dried K2EDTA tubes from two different manufacturers. All patients' samples were tested in parallel by solid phase/microplate method (Immucor ABS 2000) and the standard manual tube method. All test results for routine blood bank tests on donors' and patients' samples were concordant, demonstrating the equivalence of spray-dried K2EDTA, spray-dried K3EDTA, and liquid K3EDTA blood collection tubes for routine donor center or transfusion service testing.

Seroprevalence of Kaposi's sarcoma-associated herpesvirus infection among blood donors from Texas.

PURPOSE: Kaposi's sarcoma-associated herpesvirus (KSHV), a gammaherpesvirus recently discovered among AIDS patients with Kaposi's sarcoma, is a potential candidate for screening in blood and plasma donors. While a number of studies have assessed KSHV infection among U.S. blood donors, larger-scale population-based studies would be necessary to develop more refined estimates of the magnitude and variation of KSHV infection across different geographic regions of the U.S. blood supply. The goal of the present study, therefore, was to determine the seroprevalence of KSHV infection and to assess demographic correlates of KSHV infection among south Texas blood donors. METHODS: KSHV infection was determined using specific serologic assays that measure antibodies to KSHV latent and lytic antigens. RESULTS: The overall seroprevalence of KSHV in Texas blood donors (15.0%) is substantially higher than previously reported among blood donor and general population samples in the United States. This high rate of KSHV infection persisted across most of the sociodemographic subgroups under study but was particularly elevated among participants with less than a high school education. The infection rate also increased linearly with age. CONCLUSIONS: The elevated infection rate reported in the present study suggests that screening methods to detect KSHV infection in blood donors should be considered. In view of the etiologic role of KSHV for several malignancies, it would be important for future studies to directly assess the risk of KSHV transmission via blood transfusion.

Detection of human immunodeficiency virus type 1 p24 antigen and plasma RNA: relevance to indeterminate serologic tests.

BACKGROUND: Most enzyme immunoassay-reactive specimens producing indeterminate Western blot results belong to individuals who are not infected with human immunodeficiency virus type 1 (HIV-1). However, a small percentage may correspond to early seroconversion or advanced disease, at which stage partial reactivity on Western blot may be observed. STUDY DESIGN AND METHODS: To determine the utility of HIV-1 p24 antigen and cell-free RNA detection for the resolution of Western blot-indeterminate serologic results, several types of enzyme immunoassay-positive, sero-indeterminate specimens were analyzed. Samples were obtained from infected individuals at the time of seroconversion (n = 20), from patients with AIDS (n = 2), as specimens from clinical samples obtained for diagnostic testing (n = 57), from blood donors producing persistent indeterminate results (n = 47), and from random blood donors (n = 72). RESULTS: HIV-1 p24 antigen was detected in 10 of 20 specimens collected from 9 of 12 individuals who seroconverted and in 2 of 2 AIDS patients. HIV-1 plasma RNA was positive in 22 of 22 samples from those 14 individuals. All of 57 diagnostic specimens and 47 samples obtained from persistently indeterminate donors were negative for HIV-1 p24 antigen and plasma HIV-1 RNA. One of 72 blood donor specimens was positive for HIV-1 plasma RNA and had borderline reactivity for p24 antigen. CONCLUSION: The detection of plasma RNA appears to be sensitive and specific; negative test results may be used to identify false-positive serologic reactions. The detection of p24 antigen and plasma RNA can also be used to confirm HIV-1 infection in persons with indeterminate serologic results associated with early seroconversion or late-stage disease.

[The influence of chenodeoxycholic acid and ursodeoxycholic acid on the hepatic structure of the rat (author's transl)]. / Der Einfluss von Chenodesoxycholsäure und Ursodesoxycholsäure auf die Leberstruktur der Ratte.

Chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA) dissolve cholesterol gallstones in man. Since CDCA has caused liver damage in animal experiments we have tried to elucidate the question whether such alterations could occur due to UDCA therapy as well. CDCA and UDCA were fed orally in doses of 20, 90, 150, 250 and 1000 mg/kg body-weight daily to female Wistar-Rats (CDCA: 75 animals; UDCA: 75 animals). After 5, 30 and 60 days we examined the liver by means of light- and electronmicroscopy. After 30 days all animals treated with 1000 mg/kg CDCA had died, whereas there were no pathological findings in the UDCA treated group. By means of electronmicroscopy we detected in the CDCA-group already with 20 mg/kg/day microstructural alterations of the liver that increased with elevation of the dosage and duration of treatment. With UDCA therapy liver tissue showed minimal changes only with 1000 mg/kg. The difference is explained by the decreased rate of transformation of UDCA to lithocholic acid and the lack of toxicity of UDCA in the hepatocyte.