Advances in photoelectrocatalysis with nanotopographical photoelectrodes.

The design of photoelectrodes for high efficiency solar fuel energy conversion devices is based on the search for adequate surface conditioning to achieve efficient light harvesting, stability, minimized surface recombination losses and high electron-transfer rates at the electrolyte interface. An overview on established and novel approaches is given. A recent viable solution is provided by electroplating of nanoscale catalytic metals on passivated semiconductor surfaces, thereby forming reactive centers and avoiding contact between the semiconductor surface and the electrolyte. At these nano-dimensioned Schottky-type junctions, light-induced excess minority carriers are scavenged and transferred to the electrolyte. Various possible device configurations are outlined and envisaged systems for hydrogen or oxygen evolution and carbon dioxide reduction are presented. The role of ultrathin passivating films is emphasized and methods to fabricate open as well as compact conformal films are described.

Use of molybdenum telluride as a substrate for the imaging of biological molecules during scanning tunnelling microscopy.

Scanning tunnelling microscopy was used to image biological molecules including supercoiled deoxyribonacetic acid and specific retrovirus enzymes, the reverse transcriptases of the avian myeloblastosis virus, the moloney murine leukaemia virus and the human immunodeficiency virus. Measurements were carried out on graphite and Group VI transition metal dichalcogenide layered crystals. Images obtained with graphite could not be unequivocally interpreted and attachment appears to occur solely at surface defect sites. The layered crystal MoTe2 shows different imaging properties. The bimolecules are clearly visible, distributed over the semiconductor surface, and the molecular shapes and dimensions show good correlation with structure predictions.

Effects of glucosinolate breakdown products on the hepatic biotransformation system in male rats.

The effects of 5-vinyloxazolidine-2-thione (VOT), 1-cyano-3-butene (CYB) and various isothiocyanates on parameters of hepatic phase I and phase II biotransformation were investigated in male rats after oral treatment for 3 consecutive days. The compounds with the exception of CYB caused increases in liver weight and glutathione S-transferase activity. Cytochrome P-450 level and monooxygenase activities were decreased by the isothiocyanates and CYB. Administration of VOT resulted in contrasting response of monooxygenases: reduced aminopyrine N-demethylation and enhanced aniline hydroxylation. Possible mechanisms were discussed.

Direct observation of reverse transcriptases by scanning tunneling microscopy.

First images on a nanometer scale of reverse transcriptases (RT) of the human immunodeficiency virus (HIV-1) and of the Moloney murine leukemia virus (MuLV) obtained by scanning tunneling microscopy (STM) are reported. The common feature of the observed molecules is a ring-type or horseshoe shape with hole diameters of approximately 30 A. The STM images are compared with high resolution transmission electron microscopy (TEM) and existing structure predictions. The similarities of the structural data obtained by STM and TEM and their agreement with the structure prediction for the RT of HIV-1 shows the principal possibility to image such biomolecules by STM.

Scanning tunnelling microscopy observations of biomolecules on layered materials.

Scanning tunnelling microscopy (STM) has been performed on the reverse transcriptases of the human immunodeficiency virus (HIV-1) and the moloney murine leukaemia virus (MuLV). The biological molecules are adsorbed on n-type semiconducting MoTe2. The p66 (66 kD) subunit of the RT of HIV-1 is imaged by STM. Both STM and processed transmission electron microscopy (TEM) data show a spherical and horseshoe-like shape of external diameter ca. 65 A, depending on the angle of observation. The STM results show a larger diameter which is related to the curvature radius of the tip of the probing needle. The RTs of HIV-1 and MuLV exhibit a circular hole of ca. 20 A diameter in accordance with structure predictions and functioning considerations. The surface-molecule interaction is discussed in terms of the electronic properties of the semiconductor surface including the influence of small defect sites at the layered crystal surface.

Toxicological evaluation of rapeseed products in a subacute feeding study in rats.

Groups of 15 male rats were fed ad libitum for 4 weeks standard diet containing 0, 2.5, 5 or 10% rapeseed protein isolate (RPI), 2.5, 5 or 10% rapeseed extraction residue (RER) or 10% casein. Body weight gain and food intake were recorded weekly. Clinical chemistry analyses, haematology, urinalysis, organ weights and histology were performed terminally. Serum alanine aminotransferase was decreased by RPI, RER and casein, while serum albumin only increased in rats fed RER. Microscopic examinations revealed abnormalities in liver and kidneys of animals at the 10% RPI, RER and casein levels. The absolute liver weights showed increases in the 5 and 10% RER groups and in the 10% RPI group. The relative kidney weights were reduced at all RER levels and in the 2.5% RPI group. Antithyroid activity of the rapeseed products were not noted.

[The prenatal toxicity of butenylisothiocyanate in rats]. / Untersuchungen der Pränataltoxizität von Butenylisothiocyanat an Ratten.

Butenyl isothiocyanate (BylITC), the hydrolysis product of the glucosinolate gluconapin, present in various cruciferous vegetables and in rapeseed, was administered in oral doses of 0, 50, 100 and 150 mg/kg to pregnant rats on day 12 to 19 of gestation. Maternal toxicity was indicated by reduced body weight gain and increases in the weights of liver and kidneys. BylITC doses of 100 and 150 mg/kg caused retardation of fetal growth and ossification.

Effects of 5-vinyloxazolidine-2-thione on lactating rats and their sucklings.

5-vinyloxazolidine-2-thione (VOT) administered orally to lactating rats was found to be efficiently transferred to the sucklings via the milk. In mothers the exposure to VOT resulted in an increased percentage of neutrophils, a decreased percentage of lymphocytes and increases in the relative weights of liver and thyroid. Suckling rats showed a decreased number of leucocytes, increases in the relative weights of liver and thyroid and structural changes in the thyroid. Male sucklings were more affected than female pups. The antithyroid effects were clearly related to the maternally administered VOT doses.

Subacute oral toxicity study of benzyl isothiocyanate in rats.

The subacute toxicity of benzyl isothiocyanate (BITC) was investigated in male rats given oral doses of 0, 50, 100 and 200 mg/kg body weight/day for 4 weeks. Body weight gain and food consumption were decreased with increasing doses of BITC. Haematological changes of toxicological relevance were observed in the highest dose group. BITC administration resulted in increased serum cholesterol level in all treatment groups and decreased serum triglycerides level at 200 mg/kg. Renal dysfunction was indicated by reduced urine volume, proteinuria and enhanced urinary lactate dehydrogenase activity. BITC exposure also affected the weights of various organs and caused histological changes in the ductus choledochus, liver, ileum and mesenteric lymph nodes.

[Toxicological effect of a fatty acid mixture in rats]. / Toxikologische Wirkungen eines Fettsäuregemisches bei Ratten.

The effects of a fatty acids mixture containing nearly 50% odd numbered fatty acids (PC-Säure) were studied in a subchronic toxicity test in male and female rats. The animals received PC-Säure in their diet at levels of 0, 1.25, 2.5 and 5% for 13 weeks. Food intake was increased at 5% PC-Säure level in males. Food efficiency was initially decreased in males and females of this group. Ingestion of PC-Säure resulted in increases of the urine volume and the urinary lactate dehydrogenase activity in both sexes. Male and female rats fed PC-Säure showed elevated serum activities of alkaline phosphatase and leucine aminopeptidase and decreases in serum cholesterol and triglycerides. Dietary PC-Säure elevated the serum creatinine content in males at the two highest levels. A transitory increase in the activity of the serum alanine aminotransferase was observed in females fed 5% PC-Säure. Increased liver and kidney weights were found in both sexes.

[Toxicological evaluation of saccharose carbonic acid esters in basic subchronic feeding trials with rats. 1. Effect of saccharose fatty acid polyester]. / Toxikologische Beurteilung von Saccharosecarbonsäureestern auf der Grundlage subchronischer Fütterungsversuche mit Ratten. 1. Mitt. Wirkung von Saccharosefettsäurepolyester.

Groups of male and female rats received a sucrose fatty acid polyesters containing product (SPE) in their diet for 13 weeks at levels of 0, 5, 10 or 15%. Additional groups were pair-fed to the high-dose SPE-group (standard diet, 92.5%) or given food containing 7.5% hydrogenated lard (HF) or 4.5% fatty acid ethyl ester (FEE). Compared to the controls, there were increases in the food intake in males and females of the SPE-groups, HF- group and FEE-group. Male rats fed SPE showed increases in serum urea nitrogen at all levels, in serum alkaline phosphatase activity and urinary glucose excretion at 10 and 15%, in serum leucine amino-peptidase at 15%. In females dietary SPE increased the blood glucose content and serum alkaline phosphatase activity at 15% and the serum leucine aminopeptidase activity at 10 and 15%.

[Toxicologic evaluation of sucrose carbonic acid esters in basic subchronic feeding studies in rats. 2. Effect of sucroacetoglycerides]. / Toxikologische Beurteilung von Saccharosecarbonsäureestern auf der Grundlage subchronischer Fütterungsversche mit Ratten. 2. Mitt. Wirkung von Sucroacetoglyceriden.

Groups of male and female rats received a sucroacetoglycerides containing product (SAG) for 3 months at dietary levels of 0, 2.5, 5 and 10%. Food consumption was initially increased in females at all SAG-levels. After two weeks significant increases in food intake were observed in males and females fed 10% SAG throughout the feeding period. The serum analysis revealed significantly elevated activity in serum alkaline phosphatase at the highest SAG-level in males and females after 6 weeks and in females after 13 weeks. Histological changes related to the SAG-feeding were noted in the intestinal lymph nodes of male and female animals fed 10% SAG. The no-adverse effect level established in this subchronic feeding study was 5% SAG in the diet of rats, equivalent to a daily intake of 3.6 g/kg body weight in males and 4.0 g/kg in females.

[The subacute toxicity of glucosylthiazolidine-4-carbonic acid in rats]. / Untersuchung der subakuten Toxizität von Glucosylthiazolidin-4-carbonsäure an Ratten.

Glucosylthiazolidine-4-carbonic acid, an intermediate of the Maillard reaction between D-glucose and L-cysteine, was given in doses of 0, 25, 50 or 100 mg/kg b.w. by oral intubation to male and female rats for 21 days. General appearance, growth, food consumption, haematology, urine analysis and serum chemistry including determinations of enzyme activities, organ weights and macroscopic and microscopic pathology were used as criteria for adverse effects. Effects on the kidneys were indicated by oliguria and decreased specific gravity of the urine in males and histopathological changes of the proximal tubules in females. The no-effect dose established from this study is 25 mg/kg b.w.

[The subchronic toxicity of 5-vinyloxazolidine-2-thione in rats]. / Untersuchung der subchronischen Toxizität von 5-Vinyloxazolidin-2-thion an Ratten.

Groups of male and female rats received 5-vinyloxazolidine-2-thione (VOT) in their drinking water for 13 weeks at concentrations of 0, 10, 25, 50 or 100 mg/l and 0, 2.5 or 5 mg/l respectively. Compared with the controls, there were decreases in food intake and growth of females given VOT-doses of 10 mg/l and higher. Liquid intake was reduced in males and females of the highest dose group. Terminal haematological examination revealed an increase in white cell count at the 50 and 100 mg levels in females and a reduction in the red cell count at 100 mg/l in males. Organ weight changes were dose-related increases in the relative thyroid and liver weight and a decrease in the relative thymus weight. Structural and functional changes of the thyroid were observed in animals at levels of 10 mg/l and higher. Histological examinations of the kidneys showed tubulonephrosis in animals at and above a VOT-level of 5 mg/l. The no-observed-effect level (NOEL) established from these studies was 2.5 ml VOT/l drinking water (approximately equivalent to an daily intake of 0.4 mg/kg body weight).

[Early indicators of kidney injury in male and female rats after oral administration of cadmium]. / Erfassung frühzeitiger Nierenschädigungen anhand von Urinuntersuchungen an männlichen und weiblichen Ratten nach oraler Cadmiumexposition.

The effect of cadmium on the urinary excretion of glucose, creatinine and enzymes has been studied in adult male and female rats given the substance (70, 140 and 280 mg/kg food) for 4 weeks. Renal function tests and gel electrophoresis of urinary proteins were conducted simultaneously. Sex-dependent differences were demonstrated with regard to sensitivity of several kidney parameters and their predictive character of a possible chronic nephrotoxicity. These results were compared with hematological and general biological examinations of cadmium toxicity.

Effect of allyl isothiocyanate on hepatic monooxygenases and serum transferases in rats.

The effect of allyl isothiocyanate (AITC) on the activities of liver monooxygenases and serum transferases was investigated in male rats. AITC was given in oral doses of 0, 50, 100 or 150 mg/kg bw for 3 consecutive days. Increased relative liver weights and decreased activities of hepatic aminopyrine-N-demethylase, p-nitroanisole-O-demethylase and aniline-p-hydroxylase were observed in all treatment groups. The administration of AITC at dose levels of 100 and 150 mg/kg caused a statistically significant increase in the serum aspartate aminotransferase activity.