Recording Of Relief Structures In Amorphous Hydrogenated Carbon (a-c:h) Films For Infrared Diffractive Optics

We demonstrate the recording of diffractive structures in amorphous hydrogenated carbon (a-C:H) films using holographic exposures and reactive ion etching (RIE). The a-C:H (diamond-like) films are a very promising material in which to record relief optical structures because they ally the properties of hardness and optical quality of the coatings. The high refractive index of the material and its transparency in the infrared (IR) part of the spectrum make such structures also very interesting for recording IR transmission diffractive optical components. Such structures were holographically recorded in photoresist, and then transferred to a thin aluminium layer, which was used as a mask for the RIE of the a-C:H films. The recorded structures were analysed by scanning electron microscopy and by diffraction measurements. The good accordance between the measurements and the calculated diffraction curves demonstrates the feasibility of the material for recording diffractive optical components.45714791486Holland, L., Ojha, S.M., (1976) Thin Solid Films, 58, p. 107Angus, J.C., Koidl, P., Domitz, S., (1986) Plasma Deposited Thin Films, , edited by J. Mort and F. Jansen (Boca RaytonCRC Press)Callegari, A., Pomerene, A.T., Hovel, H.J., Babich, E.D., Purushothaman, S., Shaw, J.M., (1993) Journal of Vac. Sci. Technol. B, 11, p. 2697Kakuchi, M., Hikita, M., Tamamura, T., (1986) Appl. Phys. Lett., 48, p. 835Martino, R., Ferguson, R., Molless, A., Liebmann, L., Neisser, M., Weed, J., Callegari, S., (1995) J. Vac. Sci. Technol. B, 13, p. 2949Lima, C.R.A., Soares, L.L., Cescato, L., Alves, M.A.R., Braga, E.S., (1998) Optics Lett.Frejlich, J., Cescato, L., Mendes, G.F., (1988) Appl. Optics, 27, p. 1967Lima, C.R.A., Cescato, L., (1996) Opt. Engng., 35, p. 2804Assunçào, B.M., Costa, I.F., Lima, C.R.A., Cescato, L., (1995) Appl. Optics, 34, p. 597Petit, R., Electromagnetic Theory of Gratings (1980) Topics in Current Physics, 22. , Berlin: Springe

Diffractive Optics Produced By Holography And Rie

New diffractive optical elements were performed by holographic exposition of photoresist masks and reactive ion etching of the substrates. In particular we report the project and fabrication of a diffractive element which splits the incident unpolarized light its two orthogonal polarizations by reflection. Copyright © 1996. The Society of Photo-Optical Instrumentation Engineers.2778PART 1193194Leger, J.R., Moharam, M.G., Gaylord, T.K., (1995) Applied Optics, 34, p. 2399Knop, K., (1978) Opt Commun, 26, p. 281Gale, M.T., Knopp, K., Morf, R.H., (1990) Proc. Soc Photo-Opto Instr. Eng., 1210, p. 83Cescato, L., Gluch, E., Streibl, N., (1990) Applied Optics, 29, p. 3286Petit, R., (1980) Electromagnetic Theory of Gratings, Topics in Current Physics, 22. , Springer Verlag, Berli

Evolution of the thyroid hormone-binding protein, transthyretin

Transthyretin (TTR) belongs to a group of proteins, which includes thyroxine-binding globulin and albumin, that bind to and transport thyroid hormones in the blood. TTR is also indirectly implicated in the carriage of vitamin A through the mediation of retinol-binding protein (RBP). It was first identified in 1942 in human serum and cerebrospinal fluid and was formerly called prealbumin for its ability to migrate faster than serum albumin on electrophoresis of whole plasma

Variações florística e estrutural e relações fitogeográficas de um fragmento de floresta decídua no Rio Grande do Norte, Brasil Floristic and structural variations, and the phytogeographical relationships of a deciduous forest fragment in Rio Grande do Norte State, Brazil

O trabalho foi realizado num fragmento de floresta decídua com cerca de 270ha centrado em 5°53'S e 35°23'W e que se estende por dois ambientes edáficos distintos (Moda 1 e Moda 2). Os objetivos do trabalho foram caracterizar florística e estruturalmente o componente arbóreo nos dois ambientes, compará-los entre si e avaliar suas relações fitogeográficas. Todos os indivíduos vivos e mortos em pé com perímetro à altura do peito >10cm foram considerados como árvore e amostrados pelo método dos quadrantes. Para Moda 1 e Moda 2 foram estimados, respectivamente: densidade total de 1.587 e de 1.924 indivíduos.ha-1, área basal total de 15,88 e de 15,86m².ha-¹, freqüências modais das alturas entre 5 e 5,9m e entre 6 e 6,9m e dos diâmetros de caule entre 5,0 e 9,9cm e entre 3,2 e 4,9cm, índice de diversidade de Shannon de 3,19 e de 3,26 e índice de eqüabilidade de Pielou de 0,79 e de 0,86. Os estratos arbóreos nos dois ambientes foram considerados estruturalmente semelhantes. Foram observadas no total 66 espécies de árvores, sendo 56 em Moda 1 e 45 em Moda 2. Piptadenia moniliformis Benth. é a espécie com maior valor de importância nas duas áreas, seguidas por Tabebuia impetiginosa (Mart. ex DC.) Standl. em Moda 1 e por Chamaecrista ensiformis (Vell.) H.S. Irwin & Barneby em Moda 2. As áreas apresentam grande similaridade florística (S S = 0,69 e S C = 0,53), sendo que as espécies características de matas decíduas são mais abundantes em ou exclusivas de Moda 1, e as espécies características das Caatingas, em Moda 2. As pequenas diferenças florística e estrutural entre os dois setores da mata podem ser atribuídas às condições edáficas. Em termos florísticos, fisionômicos e ambientais, a mata foi classificada como um tipo de vegetação de transição entre as províncias fitogeográficas Atlântica e das Caatingas, com a presença destacada de espécies com ampla distribuição nas matas secas neotropicais e nos Cerrados.<br>This work was undertaken in a deciduous forest fragment (~270 ha, centered on 5°53'S and 35°23'W) spanning two distinct edaphic environments (Areas 1and 2), and sought to floristically and structurally characterize the tree layers in both environments, as well as to assess their phytogeographical relationships. All living and standing dead trees with CBH >10 cm were sampled using the point-centered quarter method. The results for areas 1and 2 were, respectively: total density, 1.587 and 1.924 individual.ha-1; total basal area, 15.88 and 15.86m².ha-1; most frequent height classes of living trees, 5-5.9m and 6-6.9m; most frequent stem diameters of living trees, 5.09.9cm and 3.2-4.9cm; Shannon diversity index 3.19 and 3.26; and Pielou evenness index, 0.79 and 0.86. The tree layers in both areas 1 and 2 were considered structurally similar. A total of 66 tree species were observed (56 in area 1 and 45 in area 2). Piptadenia moniliformis Benth. showed the greatest importance value in both areas, followed by Tabebuia impetiginosa (Mart. ex DC.) Standl. in area 1, and Chamaecrista ensiformis (Vell.) H.S. Irwin & Barneby in area 2. Both edaphic environments showed a high floristic similarity (S S = 0.69 and S C = 0.53).Species typical of deciduous forests were more abundant in, or exclusive to, area 1. Species more typical of Caatingas environments were more abundant in, or exclusive to, area 2. The small floristic and structural differences noted between the two areas are apparently attributable to soil conditions. This forest fragment contains many species showing wide distributions in both Neotropical dry forests and Cerrados, and was considered a transitional vegetation type between the Atlantic and Caatingas phytogeographical provinces, in terms of species composition and physiognomy, as well as local environment conditions