Self-assembled quantum dots in a nanowire system for quantum photonics.

Quantum dots embedded within nanowires represent one of the most promising technologies for applications in quantum photonics. Whereas the top-down fabrication of such structures remains a technological challenge, their bottom-up fabrication through self-assembly is a potentially more powerful strategy. However, present approaches often yield quantum dots with large optical linewidths, making reproducibility of their physical properties difficult. We present a versatile quantum-dot-in-nanowire system that reproducibly self-assembles in core-shell GaAs/AlGaAs nanowires. The quantum dots form at the apex of a GaAs/AlGaAs interface, are highly stable, and can be positioned with nanometre precision relative to the nanowire centre. Unusually, their emission is blue-shifted relative to the lowest energy continuum states of the GaAs core. Large-scale electronic structure calculations show that the origin of the optical transitions lies in quantum confinement due to Al-rich barriers. By emitting in the red and self-assembling on silicon substrates, these quantum dots could therefore become building blocks for solid-state lighting devices and third-generation solar cells.

Combined ultrastructural, histochemical, and autoradiographic study of osteosarcoma after preoperative chemotherapy according to the COSS 80 protocol.

Twelve osteosarcomas treated according to the COSS 80 protocol (preoperative chemotherapy, resection) were studied by light and electron microscopic, histochemical, and autoradiographic methods. Evidence of regressive and necrotic changes was found in many tumor cells, but the alterations were unspecific. Viable tumor cells of high malignancy were also observed regularly, often at the S phase. As the tumor regression continued, a strong reaction of the mononuclear phagocyte system was manifested by the presence of macrophages and giant cells.

Adjuvant chemotherapy in osteosarcoma - effects of cisplatinum, BCD, and fibroblast interferon in sequential combination with HD-MTX and adriamycin. Preliminary results of the COSS 80 study.

In a cooperative adjuvant chemotherapy study of osteosarcoma (COSS-80), 192 patients were registered from December 1979 to March 1982. Forty-one patients have been excluded from study because of their nonadjuvant situation, therapy-limiting clinical conditions, or inadequate diagnosis. One hundred and fifty-one patients have been randomized to receive either the drug combination bleomycin + cyclophosphamide + dactinomycin (BCD) or cisplatinum (CPL) within a course of sequential multidrug chemotherapy including adriamycin (ADR) and high dose methotrexate (HDMTX). After exclusion of 51 patients with some deviation in history and/or management 100 selected patients were randomized once more to receive in addition or not fibroblast interferon after preoperative chemotherapy and surgical removal of the primary tumor. Patients were stratified for age and sex and for site and extension of tumor as well in both randomizations. Median follow up is now 12 (1-16) months. The expected 2-year disease free survival (DFS) rate of the total doubly randomized group is 78% and of the single randomized group 76%. No difference could be discerned between recombined groups receiving BCD vs CPL or interferon vs no interferon. The effect of preoperative chemotherapy on the tumor was evaluated clinically and by histopathologic grading; 66/85 (78%) patients were judged clinically as responders with pathohistologic verification of this finding in 71% of these cases. No adverse effect arose from delaying definite surgery for preoperative chemotherapy, but initial application of chemotherapy as well as planning, preparing, and performing of the surgical procedure have been facilitated. The majority of patients received some kind of limb-salvage treatment without local recurrences so far. A statistically insignificant but intriguing tendency for a slightly higher incidence of pulmonary metastases after resection as opposed to amputation could be detected. Similar to observations in the previous study COSS-77.

Expression of pyruvate kinase M2 in preneoplastic hepatic foci of N-nitrosomorpholine-treated rats.

The expression of the pyruvate kinase (PK) isoenzymes L and M2 was analysed in the livers of rats treated with the hepatocarcinogenic agent N-nitrosomorpholine (NNM) in the drinking water. In control animals L-PK expression was restricted to liver parenchymal cells, whereas M2-PK was detected in bile duct epithelial, blood vessel wall, endothelial and Kupffer cells. In rats treated with NNM proliferating oval cells were consistently L-PK negative and M2-PK positive, while the ductal cells of cholangiofibroses were clearly L-PK positive and coexpressed M2-PK. However, no morphological differentiation of ductal cells into hepatocyte-like cells was observed. In the clear and acidophilic cell foci storing glycogen in excess strong staining for L-PK was observed. In glycogen-poor foci induced by NNM a shift from L-PK to M2-PK expression takes place.

Antibiotic resistance of E. coli in sewage and sludge.

The aim of the study is the evaluation of resistance patterns of E. coli in wastewater treatment plants without an evaluation of basic antibiotic resistance mechanisms. Investigations have been done in sewage, sludge and receiving waters from three different sewage treatment plants in southern Austria. A total of 767 E. coli isolates were tested regarding their resistance to 24 different antibiotics. The highest resistance rates were found in E. coli strains of a sewage treatment plant which treats not only municipal sewage but also sewage from a hospital. Among the antimicrobial agents tested, the highest resistance rates in the penicillin group were found for Ampicillin (AM) (up to 18%) and Piperacillin (PIP) (up to 12%); in the cephalosporin group for Cefalothin (CF) (up to 35%) and Cefuroxime-Axetil (CXMAX) (up to 11%); in the group of quinolones for Nalidixic acid (NA) (up to 15%); and for Trimethoprime/Sulfamethoxazole (SXT) (up to 13%) and for Tetracycline (TE) (57%). Median values for E. coli in the inflow (crude sewage) of the plants were between 2.0 x 10(4) and 6.1 x 10(4)CFU/ml (Coli ID-agar, BioMerieux 42017) but showed a 200-fold reduction in all three plants in the effluent. Nevertheless, more than 10(2)CFU E. coli/ml reached the receiving water and thus sewage treatment processes contribute to the dissemination of resistant bacteria in the environment.

Energy metabolism in the involuting mammary gland.

A strong and coordinated upregulation of the glycolytic, glutaminolytic and pentose phosphate pathway enzymes occurs during the onset of lactation in the normal mouse mammary gland. Induction of apoptosis by removing the pups led to an inactivation of the same enzymes with different time courses. While the ATP-consuming glycolytic 6-phosphofructo 1-kinase and mitochondrial bound hexokinase still remained high on days one and two of involution, the ATP-regenerating pyruvate kinase was immediately reduced. The enzymes of the pentose phosphate and glutaminolytic pathway were inactivated on the first two days of involution. In accordance with such an inactivation of the enzymes ATP, GTP, UTP, ADP, NAD NADH and lactate concentrations decreased. The synthetic product of UTP, UDP-N-acetylglucosamine, increased. AMP was found in the milk, not in the epithelial cells. The inactivation of the enzymes was caused by partial proteolysis or by a loss of the intact proteins from the cytosol without signs of proteolysis.

Comparative investigation of airborne culturable microorganisms in sewage treatment plants.

The present study investigated emissions and emmissions of airborne microorganisms (mesophilic bacteria, Escherichia coli, molds, Aspergillus fumigatus, thermophilic actinomycetes/bacilli) in sewage treatment plants. For the aerobiological investigations three sewage treatment facilities with an activated-sludge process, capacities between 2000 and 28,000 PE and different cleaning steps were selected. The measurements of microorganism emission were conducted in the area of the intake (screen), in the area of biological treatment (activated sludge tank) and at a distance of 10 m from the activated sludge tanks. In order to determine the emmission, additional measurements were conducted leeward of the plant at a distance of 200 m. Samples were taken using four parallel six-stage Andersen 1 AFCM volumetric samplers. In the area of the intake counts for bacteria were 7.4 x 10(2) CFU/m3 (median), for thermophilic actinomycetes 1.8 x 10(1) CFU/m3, for thermophilic bacilli 7.1 x 10(1) CFU/m3, for molds 2.4 x 10(3) CFU/m3 and for Aspergillus fumigatus 1.8 x 10(1) CFU/m3. Only isolated airborne coliform recoveries, i.e. E. coli, were detected. In the area of the activated sludge tank, in the adjoining area (10 m) and in the vicinity of the plants (200 m), the counts for all microorganism groups investigated corresponded to natural conditions. The results show that the counts of culturable aerogenic microorganisms in and in the immediate surrounding of the sewage plants investigated are low. Although the possibility of an infection through inhalation cannot be ruled out, the direct contact with sewage is much more critical.

[Comparative studies of airborne, cultivatable microorganisms at selected sites of waste managements, domestic animal husbandry and in the surrounding residential area]. / Vergleichende Untersuchungen luftgetragener, kultivierbarer Mikroorganismen an ausgewählten Standorten in der Abfallwirtschaft, der Nutztierhaltung und im Anwohnerbereich.

During the last years, sampling of airborne microorganisms (including mesophilic bacteria, moulds, thermophilic bacteria and A. fumigatus) in waste disposal, recycling industry and control sampling locations in the urban and rural districts of Graz was conducted using Andersen 6-stage viable cascade impactors. In the present study additional sampling in livestock buildings has been conducted. Except mesophilic bacteria the emission in the area of waste disposal and recycling industry was significantly higher than in livestock buildings. In the surroundings of the livestock buildings the number of microorganisms was not increased, while the normal background level in the surroundings of the waste proceeding plants was reached from a distance of 150 to 300 meters.

Serum-sialyltransferase activity in cancer patients.

Serum-sialyltransferase activity was measured in serum samples of 116 patients with malignant tumors of various origins and different clinical stages using asialo-fetuin as the acceptor and cytidine-5'-mono-phospho[14C]sialic acid as the donor. Only patients with metastatic tumors had significantly elevated serum-sialyltransferase levels. Increased enzyme activity was also associated with rheumatoid arthritis and with acute hepatitis, whereas no significant alteration of enzyme activity was observed in cystic fibrosis patients. In a group of tumor patients, various additional tumor markers were determined (carcinoembryonic antigen, alkaline phosphatase: Regan isoenzyme, creatinekinase: BB-isoenzyme, lactatedehydrogenase: isoenzyme 5) and the data compared to the clinical diagnoses. The sensitivity and specificity of serum-sialyltransferase as a tumor marker is assessed.

The polycyclic musk 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthaline lacks liver tumor initiating and promoting activity in rats exposed to human-relevant doses.

7-Acetyl-1,1,3,4,4,6-hexamethyl- 1,2,3,4-tetra-hydronaphthaline (AHTN) is one of the two most widely used fragrances of a group of substances known collectively as the polycyclic musks. In the last few years evidence has been accumulating that AHTN is hepatotoxic when administered at high doses. In the present study the subchronic hepatotoxicity of AHTN administered to rats at doses within the human exposure range was evaluated. For this purpose female and male juvenile Wistar rats were exposed to AHTN (300 microg/kg body weight per day, i.p.) alone or to a single dose of diethylnitrosamine (DEN) (100 mg/kg body weight, i.p.) followed by AHTN (1, 10, 100 or 300 microg/kg body weight per day, i.p.) for 90 days. Thereafter the liver architecture as well as the presence of placental glutathione S-transferase (GST-P)-positive hepatic lesions was assessed. In male animals receiving AHTN alone or in combination with DEN the number of GST-P-positive single hepatocytes was similar to that in untreated rats, while GST-P-positive mini-foci and foci were not observed. In the case of female rats the number of GST-P-positive single hepatocytes and mini-foci in AHTN-treated rats was similar to that in untreated animals, whereas in those animals receiving AHTN either alone or in combination with DEN, GST-P-positive foci could not be detected or were present in a number as similar to that in untreated rats. In conclusion, in the present study it has been shown that AHTN administered over a 90-day period in concentrations similar to those taken up daily by humans does not lead to hepatotoxicity.

Comparative investigations of airborne culturable microorganisms in selected waste treatment facilities and in neighbouring residential areas.

The evaluation of airborne microorganisms in waste treatment facilities is complicated by different measuring systems, a lack of measuring standards and large variations between individual counts. In the present study, different sectors of the waste management industry were compared by determining median values of airborne culturable microorganisms from numerous parallel counts over a prolonged time period. The samples were taken during the warm season using the six-stage Andersen volumetric sampler in a large composting plant and its immediate vicinity, in an agricultural composting plant, a waste disposal site, and a sorting facility for recyclable materials. Control samples were taken at a site not influenced by the waste management industry in an open and largely uninhabited area. The highest median values for culturable bacteria (37 degrees C) found were 1.1 x 10(5) CFU/m3, for moulds (25 degrees C) 1.4 x 10(5) CFU/m3, and for A. fumigatus (37 degrees C) 1.7 x 10(4) CFU/m3 in the sorting cabins of the sorting facility (p < 0.001). The highest median values for thermophilic bacteria (actinomycetes and bacillaceae, 50 degrees C) were 7.3 x 10(3) CFU/m3 in the large composting facility. In all other facilities as well as in the neighbouring residential areas of all facilities investigated, all median values were significantly lower and corresponded to the naturally occurring levels: approx. 10(2) CFU/m3 for bacteria, approx. 10(3) CFU/m3 for moulds and approx. 10(1) CFU/m3 for A. fumigatus and thermophilic bacteria. Only in the neighbouring residential area of the large composting plant, the median values for thermophilic bacteria were approx. 10(2) CFU/m3, but an additional impact from farms cannot be excluded in this case. These results show permanent increased loads of the investigated microorganisms inside large composting facilities and especially in the sorting cabins for recyclable materials. The increasing number of reports on potential health hazards in these areas require adequate measures on the part of occupational medicine in order to limit the health risk to a minimum. The most important task is the automatization of the sorting process for recyclable materials.