Microbial selenium sulfide reduction for selenium recovery from wastewater.

Microbial reduction of selenium sulfide (SeS2) is a key step in a new treatment process to recover selenium from selenate and selenite streams. In this process, selenate is first reduced to selenite, and subsequently selenite is reduced by sulfide and precipitates from the solution as SeS2. The latter is bio-reduced to elemental selenium and sulfide. Two anaerobic granular sludges (Eerbeek and Emmtec) were tested for their efficiency to reduce commercial crystalline SeS2. Emmtec sludge had the highest reducing capacity with commercial SeS2 and was therefore also used for the bioreduction of laboratory synthesized amorphous SeS2. Synthesized SeS2 was formed mixing a sulfide solution and effluent containing selenite. With both SeS2 solids (commercial and synthesized SeS2), Emmtec sludge produced sulfide and a solid consisting of hexagonal elemental selenium. The crystalline hexagonal structure suggests the absence of biomolecules, which stabilize amorphous selenium bio-particles under comparable process conditions (T=30°C and a pH between 6 and 7). Selenium particles were not attached to the biomass, suggesting an extracellular formation. The results support the feasibility of the bio-reduction process using sulfur for recovering selenium from water.

Parallel fabrication of magnetic tunnel junction nanopillars by nanosphere lithography.

We present a new method for fabricating magnetic tunnel junction nanopillars that uses polystyrene nanospheres as a lithographic template. Unlike the common approaches, which depend on electron beam lithography to sequentially fabricate each nanopillar, this method is capable of patterning a large number of nanopillars simultaneously. Both random and ordered nanosphere patterns have been explored for fabricating high quality tunneling junctions with magnetoresistance in excess of 100%, employing ferromagnetic layers with both out-of-plane and in-plane easy axis. Novel voltage induced switching has been observed in these structures. This method provides a cost-effective way of rapidly fabricating a large number of tunnel junction nanopillars in parallel.

[Psychopathology in female carriers of the fragile X mutation]. / Psychopathologie bij draagsters van de fragiele-X-mutatie.

Fragile X syndrome is, after Down's syndrome, the most common form of mental retardation. Women are potential carriers and can have the defective gene on one of their two X chromosomes without developing the complete syndrome. In this paper we examine which psychiatric disturbances may appear or develop in women because they are carriers of the fragile X mutation. Carriers have been found to have a higher frequency of anxiety disorders, affective disorders and schizotypal features.

Excess vitamin E decreases canthaxanthin absorption in the rat.

The recent attention given to the possible role of alpha-tocopherol (alpha-Toc) and carotenoids in the prevention and treatment of a variety of illnesses resulted in segments of the population increasing their consumption of these nutrient/antioxidants. Once consumed, alpha-Toc and carotenoids are thought to follow the same absorptive pathway and may influence each other's absorption, particularly when taken in large doses. The purpose of this study was to determine if alpha-Toc and the carotenoid, canthaxanthin (CTX), interact during absorption. Rats were intraduodenally infused with corn oil emulsions containing combinations of alpha-Toc (0 or 300 mumol/L) and CTX (5, 10, 15, 20 mumol/L) in a 2 x 4 factorial arrangement. Absorption was determined by measuring recovery of CTX and alpha-Toc in the mesenteric lymph. The amount of CTX in the lymph increased significantly with the amount infused into the duodenum. The overall efficiency of CTX absorption from emulsions without alpha-Toc averaged 12% with individual animals having a range of 8 to 18%. Efficiency of absorption was not related to concentration of CTX infused. When alpha-Toc (300 mumol/L) was added to the oil emulsion, the absorption of CTX was decreased by at least 50%. Recovery of alpha-Toc in the lymph averaged ca. 10% and was not affected by CTX. These results suggest that concurrent consumption of a large dose of alpha-Toc may influence carotenoid bioavailability.

Characteristics of small breast and/or ovarian cancer families with germline mutations in BRCA1 and BRCA2.

For families with a small number of cases of breast and/or ovarian cancer, limited data are available to predict the likelihood of genetic predisposition due to mutations in BRCA1 or BRCA2. In 104 families with three or more affected individuals (average 3.8) seeking counselling at family cancer clinics, mutation analysis was performed in the open reading frame of BRCA1 and BRCA2 by the protein truncation test and mutation-specific assays. In 31 of the 104 families tested, mutations were detected (30%). The majority of these mutations (25) occurred in BRCA1. Mutations were detected in 15 out of 25 families (60%) with both breast and ovarian cancer and in 16 out of 79 families (20%) with exclusively cases of breast cancer. Thus, an ovarian cancer case strongly predicted finding a mutation (P < 0.001). Within the group of small breast-cancer-only families, a bilateral breast cancer case or a unilateral breast cancer case diagnosed before age 40 independently predicted finding a BRCA1 or BRCA2 mutation (P = 0.005 and P = 0.02, respectively). Therefore, even small breast/ovarian cancer families with at least one case of ovarian cancer, bilateral breast cancer, or a case of breast cancer diagnosed before age 40, should be referred for mutation screening.

BRCA1 genomic deletions are major founder mutations in Dutch breast cancer patients.

To date, more than 300 distinct small deletions, insertions and point mutations, mostly leading to premature termination of translation, have been reported in the breast/ovarian-cancer susceptibility gene BRCA1. The elevated frequencies of some mutations in certain ethnic subpopulations are caused by founder effects, rather than by mutation hotspots. Here we report that the currently available mutation spectrum of BRCA1 has been biased by PCR-based mutation-screening methods, such as SSCP, the protein truncation test (PTT) and direct sequencing, using genomic DNA as template. Three large genomic deletions that are not detected by these approaches comprise 36% of all BRCA1 mutations found in Dutch breast-cancer families to date. A 510-bp Alu-mediated deletion comprising exon 22 was found in 8 of 170 breast-cancer families recruited for research purposes and in 6 of 49 probands referred to the Amsterdam Family Cancer Clinic for genetic counselling. In addition, a 3,835-bp Alu-mediated deletion encompassing exon 13 was detected in 4 of 170 research families, while an deletion of approximately 14 kb was detected in a single family [corrected]. Haplotype analyses indicated that each recurrent deletion had a single common ancestor.

A high proportion of novel mutations in BRCA1 with strong founder effects among Dutch and Belgian hereditary breast and ovarian cancer families.

We have identified 79 mutations in BRCA1 in a set of 643 Dutch and 23 Belgian hereditary breast and ovarian cancer families collected either for research or for clinical diagnostic purposes. Twenty-eight distinct mutations have been observed, 18 of them not previously reported and 12 of them occurring more than once. Most conspicuously, a 2804delAA mutation has been found 19 times and has never been reported outside the Netherlands. A common haplotype spanning > or = 375 kb could be identified for each of the nine examined recurrent mutations, indicating the presence of multiple BRCA1 founder mutations in the Dutch population. The 2804delAA mutation has been estimated to have originated approximately 32 generations ago. No specific breast or ovarian cancer phenotype could be assigned to any of the common mutations, and the ovarian cancer incidence among 18 families with the 2804delAA mutation was heterogeneous.