Determination and analysis of the optical constants of thin films of nickel(II) and copper(II) hydrazone complexes by spectroscopic ellipsometry

Thin films of four nickel(II) and copper(II) hydrazone complexes, which will hopefully be used as recording layers for the next-generation of high-density recordable disks, were prepared by using the spin-coating method. Absorption spectra of the thin films on K9 optical glass substrates in the 300-700 nm wavelength region were measured. Optical constants (complex refractive indices N) and thickness d of the thin films prepared on single-crystal silicon substrates in the 275-675 nm wavelength region were investigated on a rotating analyzer-polarizer scanning ellipsometer by fitting the measured ellipsometric angles (Psi(lambda) and Delta(lambda)) with a 3-layer model (Si/dye film/air). The dielectric functions epsilon and absorption coefficients alpha as a function of the wavelength were then calculated. Additionally, a design to achieve high reflectivity and optimum dye film thickness with an appropriate reflective layer was performed with the Film Wizard software using a multilayered model (PC substrate/reflective layer/dye film/air) at 405 nm wavelength.

Nickel(II) and copper(II) complexes containing 2-(2-(5-substitued isoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione ligands: Synthesis, spectral and thermal characterizations

Two new hydrazone chelating ligands, 2-(2-(5-methylisoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione (HL1) and 2-(2-(5-tert-butylisoxazol-3-yl)hydrazono)-5,5-dimethylcyclohexane- 1,3-dione (HL2), and their nickel(II) and copper(II) complexes were synthesized using the procedure of diazotization, coupling and metallization. Their structures were postulated based on elemental analysis, H-1 NMR, ESI-MS, FT-IR spectra and UV-vis electronic absorption spectra. Smooth films of these complexes on K9 glass substrates were prepared using spin-coating and their absorption properties were evaluated. The thermal properties of the metal(II) complexes were investigated by thermogravimetry (TG) and differential thermogravimetry (DTG). Different thermodynamic and kinetic parameters namely activation energy (E

Physiological Determinants of Invasive Success Linking Distribution Patterns to Metabolic Physiology in Native and Invasive Blue Mussels (genus Mytilus)

In the early 20th century, a blue mussel species from the Mediterranean invaded the California coast and subsequently out-competed the native species south of Monterey Bay. Like other invasive species, Mytilus galloprovincialis has physiological traits that make it successful in habitats formerly occupied by the native M. trossulus, namely its adaptation to warm sea surface temperatures. This study looks at the current genotype distributions and enzymatic activities of field-acclimatized mussels within the hybrid zone where the species co-occur as well as mussels that have been acclimated for four weeks to different temperature and salinity conditions. In the field-acclimatized and laboratory-acclimated mussels, the native species exhibited significantly higher enzyme rates, which may reflect an evolutionary adaptation to compensate to low habitat temperatures. Indeed, the results of the laboratory acclimation indicate that these differences are genetically based. Whether an acclimation capacity exists may require even longer-term acclimation to different temperatures. Current findings suggest that the further spread of the invasive species is likely to be governed in large measure by the potentially counteracting effects of rising temperatures, which would favor the northerly spread of M. galloprovincialis, and increased winter precipitation, which would favor the persistence of M. trossulus. However, the success of M. galloprovincialis during acclimation to ‘dilute’ salinity (25 ppt) suggests that the invasive species can tolerate a greater salinity range than previously thought. Thus, further investigation is needed to build a comprehensive predictive model of the movement of M. galloprovincialis and the hybrid zone along the California coast.

The effect of organotin and copper sulfate on the late development and presettlement behavior of the hard clam Mercenaria mercenaria

The effect of organotin compounds and copper, commonly used as antifouling agent, were studied on Mercenaria mercernaria larvae. They were reared under usual hatchery conditions until they reached 190 um in diameter. The larvae were subjected to four compounds, tributylin chloride (TBT), monobutyltin chloride (MBT), trimethyltin chloride (TMT), cupric sulfate (CuSo4) plus control. Mortality was measured at 24, 48 h, and 96h. Behavioral and/or metamorphic changes were recorded in triplicate at 24-48 and 96 h. The appearance in swimming larvae of a functional foot was considered a sign of competence to set and was recorded as a "pediveliger". Swimming larvae were considered as larvae that have not yet reached their total development and they were recorded as "swimming". Larvae that did not show foot or swimming activity and were static but alive on the bottom were recorded as "bottom". TBT was found to completely inhibit swimming activity at sublethal concentrations throughout the period of observation. Copper and MBT inhibited swimming from 48 h, TMT did not inhibit swimming activity at any of the times recorded. The four compounds ranked in order of decreasing toxicity were TBT>TMT>CU>MBT.

M(C6H16N3)2(VO3)4 as heterogeneous catalysts. Study of three new hybrid vanadates of cobalt(II), nickel(II) and copper(II) with 1-(2-aminoethyl)piperazonium.

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Developing aquaculture of Small Native Species (SNS) in Bangladesh: village level agroecological change and the availability of SNS

Small native species (SNS) of fish are important source of protein and income for rural people in Bangladesh. A rapid rural appraisal study was carried out to explore the recent changes in the availability of SNS in relation to agroecology and related issues. Village residents noted that the availability of SNS had declined drastically due to habitat loss related to agricultural intensification and due to the restriction of access to the remaining habitats in the course of aquaculture development. Their perception was that poor people had gained from the intensification of agriculture in terms of rice consumption but had lost in terms of reduced access to fish and other animal products.

Deleterious effects of non-native species introduced into Lake Victoria, East Africa

Lake Victoria, in East Africa, has suffered from introductions and invasions of non-native species such as Lates niloticus, various tilapiine species, and Eichornia crassipes since the 1950s. These have had a devastating effect on the natural biological communities. This paper reviews the effects of the introductions on ecology, environment, fisheries and the local human population.