Photoinduced 3D orientational order in side chain liquid crystalline azopolymers

We apply experimental technique based on the combination of methods dealing with principal refractive indices and absorption coefficients to study the photoinduced 3D orientational order in the films of liquid crystalline (LC) azopolymers. The technique is used to identify 3D orientational configurations of trans azobenzene chromophores and to characterize the degree of ordering in terms of order parameters. We study two types of LC azopolymers which form structures with preferred in-plane and out-of-plane alignment of azochromophores, correspondingly. Using irradiation with the polarized light of two different wavelengths we find that the kinetics of photoinduced anisotropy can be dominated by either photo-reorientation or photoselection mechanisms depending on the wavelength. We formulate the phenomenological model describing the kinetics of photoinduced anisotropy in terms of the isomer concentrations and the order parameter tensor. We present the numerical results for absorption coefficients that are found to be in good agreement with the experimental data. The model is also used to interpret the effect of changing the mechanism with the wavelength of the pumping light.Comment: uses revtex4 28 pages, 10 figure

Conceptual design of a winged hybrid airship

The present study focuses on the sizing and aerodynamic contour design of a two-seater 1000 kg gross take-off mass winged hybrid airship. Unlike the conventional hybrid airships, which stay aloft and takeoff with the help of VTOL propulsion systems, a winged hybrid airship requires a certain speed to takeoff by utilizing lift coming from its aerodynamic surfaces. Heaviness fraction and takeoff ground roll are considered as measure of merit in initial sizing. Based on the design requirement of Malaysian inter-island tourism and transportation of agricultural products, range is set to 450 km and ground roll for take-off about 150 m. For the airship to be heavy enough for ground handling, the ratio of hydrostatic to hydrodynamic lift is set equal to 49:51. Summary of the results to be obtained in early design phase will give a baseline start to study the aerodynamics and stability characteristics of such airships in future

AD51B in Familial Breast Cancer

Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possible recurrent founder mutations. In addition, we studied the known rs999737, rs2588809, and rs1314913 SNPs and RAD51B haplotypes in 44,791 breast cancer cases and 43,583 controls from 40 studies participating in the Breast Cancer Association Consortium (BCAC) that were genotyped on a custom chip (iCOGS). We identified one putatively pathogenic missense mutation c.541C>T among the Finnish cancer patients and subsequently genotyped the mutation in additional breast cancer cases (n = 5259) and population controls (n = 3586) from Finland and Belarus. No significant association with breast cancer risk was seen in the meta-analysis of the Finnish datasets or in the large BCAC dataset. The association with previously identified risk variants rs999737, rs2588809, and rs1314913 was replicated among all breast cancer cases and also among familial cases in the BCAC dataset. The most significant association was observed for the haplotype carrying the risk-alleles of all the three SNPs both among all cases (odds ratio (OR): 1.15, 95% confidence interval (CI): 1.11–1.19, P = 8.88 x 10−16) and among familial cases (OR: 1.24, 95% CI: 1.16–1.32, P = 6.19 x 10−11), compared to the haplotype with the respective protective alleles. Our results suggest that loss-of-function mutations in RAD51B are rare, but common variation at the RAD51B region is significantly associated with familial breast cancer risk

Effect of selenium supplementation in hypothyroid subjects of an iodine and selenium deficient area: the possible danger of indiscriminate supplementation of iodine-deficient subjects with selenium.

Selenium and seleno dependent glutathione peroxidase (GPX) deficiency has been described in endemias of myxedematous cretinism. In northern Zaire, a selenium supplementation trial has been conducted. Beside correcting the GPX activity, two months of selenium supplementation was shown to modify the serum thyroid hormones parameters in clinically euthyroid subjects and to induce a dramatic fall of the already impaired thyroid function in clinically hypothyroid subjects. These results further support a role of selenium in thyroid hormone metabolism. In an iodine deficient area, this selenium deficiency could lead to opposite clinical consequences: protect the general population and the fetus against iodine deficiency and brain damage; and in turn, favour the degenerative process of the thyroid gland leading to myxoedematous cretinism.Case ReportsJournal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

The end of moai quarrying and its effect on Lake Rano Raraku, Easter Island.

International audienc

Selenium status in pregnant women of a rural population (Zaire) in relationship to iodine deficiency

Endemic myxoedematous cretinism has been associated with combined selenium and iodine deficiency in several areas of Zaire. To determine selenium and iodine status across the country, serum selenium and thyroid function parameters including urinary iodide were determined at prenatal clinics in 30 health centres of rural villages distributed over the whole country. Only in Bas-Zaire was the mean serum selenium level similar to that in non-deficient areas (80–120 ng/ml); in the regions of Bandundu and Kasai levels were marginally decreased (55–80 ng/ml), and in Kivu, Haut-Zaire, Equateur and Shaba they were marginally or moderately decreased (5mU/l) was present in every region, with a frequency ranging from 3% in Kivu to 12% in Equateur. Iodine deficiency affects most of the Zairean population and requires public health measures on a larger scale than previously estimated. Combined iodine and selenium deficiency affects Equateur, Haut-Zaire and Kivu, where endemic myxoedematous cretinism occurs, but also Shaba, where it was not previously described. Besides combined iodine and selenium deficiency which is permissive, another factor (thiocyanate?) must be taken into account to explain the peculiarly elevated prevalence of endemic myxoedematous cretinism in Central Africa.FLWINinfo:eu-repo/semantics/publishe