PHOTO CHROMATIC SENSORS OF MULTINARY MIXED VALENCE INORGANIC MICRO NEEDLES

The recent I-U measurements on the individual micro needle-shaped crystals, of the ternary mixed valence compound In5Se5Cl, crystallizing in the monoclinic crystal system (P21/m), showed significant light sensitivities. Micro needles of In5Se5Cl “glued” on Si- and Cu- substrates were measured under five different wavelengths with various irradiation intensities to investigate their photo chromatic sensing behavior along with the substrate’s influence. In the measuring voltage range 0 – 3 V and maximal LED illumination intensity, current jumps above two orders of magnitude were observed for white light (4100 K; 200 lm), followed by the blue light (460 nm; 976 mW). The amber light (590 nm; 203 mW) exhibited the lowest response. Green- and blue light were selected to determine the substrate’s effect. The micro-needles chips prepared with Si-substrates displayed higher currents for the same voltages in comparison to those prepared with Cusubstrates. These differences decreased with the voltage increase for both employed wavelengths. The mutual structural substitution of a selenium with sulfur, led to the compound In5Se4Cl. The later crystallizes similarly to In5Se5Cl. Its I-U measurements recorded with green and blue light, on Cu-substrate chips within the voltage range 0 -3 V, revealed more pronounced photo chromatic sensorial for both wavelengths used. These differences increased with the voltage increase for both employed wavelengths. At 3 V, current increases up to 2.2 times and 2.4 times were observed for the green light and blue light respectively. Typically high and better distinguishable sensorial activity was observed for all the employed wavelengths using chips with In5Se4Cl crystals on Cu-substrate, even at minimal irradiation LED power (0.25 %). The micro-reflection measurements of both needle-shaped crystals displayed a substitution dependent band-gap. For In5Se5Cl the band gap was estimated at 580 nm. Thickness interference oscillations strongly damped due to structural inhomogeneity or defect-related absorption suggest two possible band gaps for In5Se4Cl; at 540 nm or at 620 nm

ANANALYTICAL STUDY OF MARBLE CONSOLIDATION BY OXALATE PRECIPITATION USING DENSITY, FTIR AND POWDER-XRD MEASUREMENTS

oai:ojs2.www.jepm.rs.ba:article/28Our recent study on consolidation of marble samples with the purpose of culture heritage protection occurred by periodical calcium oxalate precipitation on top of quasi parallelepipedic samples. The overall process consisting of three stages of treatment, starting with 5 % calcium acetate solution for 60 minutes at 20°C, a draining step at 70°C for 30 min, followed by a treatment with 5 % ammonium sulfate solution, it followed with the third stage which includes the treatment with 5% ammonium oxalate solution revealed a continuous density increace, determined using ethanol. As the natural samples had an initial density of 2.5871 g/cm3 , it increased up to 2.6980 g/cm3 for 50 times treatments. The precipitation of oxalate on top of calcium carbonate substrate, in form of calcite, revealed two distinguished infra-red bands, at 1316 cm-1 and 1624 cm-1 unsymmetrically located around the carbonate one at 1426 cm-1 .The intensity of the bands was proportional to the number of treatments. The continuous surface coverage investigated in parallel by powder XRD evidenced the presence of whewellite crystallites deposited on top of calcite, and their intensity increasing as well with the number of treatments. This method exhibits a reliable oxalate coverage of marble sample surfaces which doesn’t influence considerably their water solubility

Ectoparasitos de cães no ambiente doméstico da vertente Caribe, Costa Rica

Reports on ectoparasites on dogs in Central America are scarce. The aim of this study was to identify flea, louse and tick species infesting dogs in home environments on the Caribbean slope of Costa Rica, and determine their frequency and coexistence. Ectoparasites were collected from dogs in 83 rural homes at five study sites. Specimens were identified and separated according to species. Fleas were the most common ectoparasite (G = 22,217, DF = 8, p = 0.004). Ctenocephalides felis and Pulex simulans were found in 83% and 55% of the homes with ectoparasites, respectively. Trichodectes canis (13%), Heterodoxus spiniger (10%), Rhipicephalus sanguineus (18%), Rhipicephalus (Boophilus) microplus (5%) and Amblyomma ovale (8%) were also present. More than one species was collected in most cases (66%), and the most common combination was C. felis and P. simulans (59% of homes with fleas). The high frequency of P. simulans emphasizes the need for adequate identification. This was the first study involving different ectoparasites of dogs in Costa Rica, as well as the first report of T.  canis in this country. The relative frequency and coexistence of these ectoparasites in the home environment may have implications for animal and human health.Relatos de ectoparasitos em cães da América Central são escassos. O objetivo deste estudo foi identificar espécies de pulgas, piolhos e carrapatos que infestam os cães no ambiente doméstico da vertente Caribe da Costa Rica, determinando sua frequência e coexistência. Foram coletados ectoparasitos de cães em 83 casas rurais de cinco sítios do estudo. Os indivíduos foram separados e identificados. Os ectoparasitos mais comuns foram as pulgas (G = 22.217, DF = 8, p = 0.004). Ctenocephalides felis e Pulex simulans foram observados em 83% e 55% das moradias com ectoparasitos, respectivamente. Da mesma forma também foram observados Trichodectes canis (13%), Heterodoxus spiniger (10%), Rhipicephalus sanguineus (18%), Rhipicephalus (Boophilus) microplus (5%) e Amblyomma ovale (8%). Na maioria dos casos, mais de uma espécie foi achada (66%), sendo que a combinação mais comum foi C. felis e P. simulans (59% de moradias com pulgas). A frequência alta de P. simulans ressalta a necessidade de sua adequada identificação. Este é o primeiro estudo que envolve diferentes ectoparasitas de cães na Costa Rica, da mesma forma, é o primeiro relato de T.  canis no país. A frequência relativa e coexistência destes ectoparasitos no ambiente domiciliar poderiam ter implicações na saúde animal e humana.Universidad de Costa Rica/[803-A8-127]/UCR/Costa Rica/[9-N-2008]/NeTropica/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Estructuras Microscópicas (CIEMIC)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí