Climate change and pollution speed declines in zebrafish populations.

Endocrine disrupting chemicals (EDCs) are potent environmental contaminants, and their effects on wildlife populations could be exacerbated by climate change, especially in species with environmental sex determination. Endangered species may be particularly at risk because inbreeding depression and stochastic fluctuations in male and female numbers are often observed in the small populations that typify these taxa. Here, we assessed the interactive effects of water temperature and EDC exposure on sexual development and population viability of inbred and outbred zebrafish (Danio rerio). Water temperatures adopted were 28 °C (current ambient mean spawning temperature) and 33 °C (projected for the year 2100). The EDC selected was clotrimazole (at 2 µg/L and 10 µg/L), a widely used antifungal chemical that inhibits a key steroidogenic enzyme [cytochrome P450(CYP19) aromatase] required for estrogen synthesis in vertebrates. Elevated water temperature and clotrimazole exposure independently induced male-skewed sex ratios, and the effects of clotrimazole were greater at the higher temperature. Male sex ratio skews also occurred for the lower clotrimazole exposure concentration at the higher water temperature in inbred fish but not in outbred fish. Population viability analysis showed that population growth rates declined sharply in response to male skews and declines for inbred populations occurred at lower male skews than for outbred populations. These results indicate that elevated temperature associated with climate change can amplify the effects of EDCs and these effects are likely to be most acute in small, inbred populations exhibiting environmental sex determination and/or differentiation.

Synthesis and characterization of multifunctional periodic mesoporous organosilica from diureidophenylene bridged organosilica precursor.

This paper reports the periodic mesoporous organosilicas (PMOs) functionalised with newly synthesized bis-silylated (1,1(1,4-phenylene (bis-3-(3-triethoxysilylpropyl)urea)(BSBDA)) organosilica with 1,2-bis(triethoxysilyl) ethane (BTSE) using a co-condensation process. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), nitrogen adsorption-desorption, NMR (proton, 13C and 29Si) spectra, and MALDI-TOF were used to characterise and evaluate the structural properties. The results showed that BSBDA is linked covalently to the mesochannel of the PMO frameworks. The pore size and overall structural properties in the functionalised PMOs were found to depend on the loading amounts of BSBDA. The overall results suggested that the highly functionalised PMOs could be tuned even at high BSBDA loadings (25 wt%).

Hydrothermally stable periodic mesoporous ethane-silica and bimodal mesoporous nanostructures.

We report the hydrothermally stable organized periodic mesoporous organosilicas (PMOs) and bimodal mesoporous structures by using mixed templates of oligomeric alkyl-ethylene oxide and ionic surfactants under basic conditions. Oligomeric alkyl-ethylene oxide surfactant [(Polyoxyethylene (2) cetyl ether, structure is C16H33(OCH2CH2)nOH, n-2, hereafter known as B52) and ionic surfactant (cethyltrimethylammonium bromide (CTAB)) templating systems form mixed micelles that self-assemble into well-ordered hexagonal and bimodal mesostructures. The X-ray diffraction (XRD), transmission electron microscopy (TEM), BET, NMR and hydrothermal study have been used to investigate the effects of B52 on the formation of various PMOs. It is found that surface structural properties of mesostructures largely depend on the concentration of the B52 in the surfactant solution. The addition of B52 in the surfactant solution is not only improves mesostructural ordering and also enables to produces mesostructures with tuned surface structural properties. The final PMO structure shows good hydrothermal stability and can withstand for 72 h in boiling water, due to the hydrophobic pore wall chemistry in ethane-bridged PMO framework (triple bond Si-CH2-CH2-Si triple bond) and relatively more condensed framework such T3 supported by NMR spectrum. So, the lacking affinity for water through the favorable hydrophobic framework chemistry enhances the hydrothermal stability.

Photoactive perylenediimide-bridged silsesquioxane functionalized periodic mesoporous organosilica thin films (PMO-SBA15): synthesis, self-assembly, and photoluminescent and enhanced mechanical properties.

Well-organized periodic mesoporous organosilica thin films (designated as PMO-SBA15), having covalently bonded perylene-bridged silesquioxane (PTCDBS) inside their pore channels, are successfully synthesized via sol-gel self-assembly of 1,2-bis(triethoxysilyl)ethane and perylene-bridged silsesquioxane, using micelles of pluronic surfactant (P123) as a template for the first time. The surfactant is successfully removed from the pore channels of PMO-SBA15 by an acidic solvent extraction procedure. The final PMO-SBA15 thin films are characterized by high resolution X-ray diffraction (HRXRD), transmission electron microcopy (TEM), solid-state 29Si and 13C NMR CP/MAS NMR spectroscopy, nitrogen adsorption-desorption measurements, photoluminescence (PL) spectroscopy, and nanoindentation. HRXRD data reveal the formation of well-organized hexagonal channels in the pure PMO-SBA15 films. The intensity of the diffracted X-ray, however, systematically attenuates after incorporation of the perylene functionality inside the hexagonal channels. This is attributed to the low X-ray scattering contrast between the mesostructured organosilica walls and organic moieties (perylene) inside the channels, suggesting the successful incorporation of the photoactive perylene molecules inside the nanochannels. This was further confirmed by photoluminescence spectroscopy and nitrogen adsorption-desorption measurements. Additionally, the mechanical hardness of the functionalized PMO-SBA15 thin films, measured by nanoindentation, is significantly enhanced as compared with that of the pure PMO film. Thermogravimetric analysis (TGA) and elemental analysis suggested the functionalized PMO-SBA15 materials with PTCDBS.

Self-assembly, optical, and mechanical properties of surfactant-directed biphenyl-bridged periodic mesostructured organosilica films with molecular-scale periodicity in the pore walls.

Self-assembly, optical, and mechanical properties of surfactant-directed biphenyl-bridged periodic mesoporous organosilica thin films (PMOF-Bp's) with molecular-scale periodicity in the pore walls were successfully demonstrated for the first time. The biphenyl-bridged organosilica precursor, 4,4-bis(triethoxysilyl)biphenyl (Bp-TES) has been used as the sole precursor (100%) for preparing PMOF-Bp films with molecular-scale periodicity in the pore walls via the surfactant-mediated one-step mild acidic self-assembly process. High-resolution X-ray diffraction (HRXRD) patterns and transmission electron microscope (TEM) images of PMOF-Bp materials confirmed the formation of a biphenyl-bridged periodic mesophase with molecular-scale periodicity in the organosilica framework. Fourier transform infrared (FT-IR) and NMR spectroscopic data also strongly suggested that the biphenyl organic segment is covalently bonded with silicon atoms in the acidic ethanol-washed biphenyl-bridged mesoporous framework. The emission behavior is sensitive to synthesis and thermal treatment temperatures. The biphenyl-bridged PMO films show absorption and emission due to the presence of biphenyl segment in pore walls. Nanoindentation hardness of the PMOF-Bp films could be controlled by temperature, degree of pore ordering and molecular periodicity, and even thickness of films. For example, well-organized PMOF-Bp film with molecular-scale periodicity in the pore walls showed a higher hardness value (0.23 GPa) than that of less mesoordered PMOF-Bp film (0.13 GPa). For all solvent-extracted PMO samples, N(2) gas sorption experiments showed the surface area (from 714 to 688 m(2)/g), the pore volume (from 0.76 to 0.68 cm(3)/g), and pore size (2.81 to 3.1 nm). The solid-state NMR and FT-IR spectroscopic data were used to propose plausible interpretations of the formation of hydrogen-bonded molecular periodicity in the pore walls. The experimental periodicity value 1.40 nm was strongly supported by the periodicity obtained by the structural model (1.389 nm).

Linking human nutrition and fisheries: incorporating micronutrient-dense, small indigenous fish species in carp polyculture production in Bangladesh.

BACKGROUND: Fish and fisheries are important for the livelihoods, food, and income of the rural population in Bangladesh. Increased rice production and changing agricultural patterns have resulted in a large decline in inland fisheries. Implementation of carp pond polyculture has been very successful, whereas little focus has been given to the commonly consumed small indigenous fish species, some of which are rich in vitamin A and minerals, such as calcium, iron, and zinc, and are an integral part of the rural diet. OBJECTIVE: The overall objective of the research and capacity-building activities described in this paper is to increase the production, accessibility, and intake of nutrient-dense small indigenous fish species, in particular mola (Amblypharyngodon mola), in order to combat micronutrient deficiencies. The large contribution from small indigenous fish species to recommended intakes of vitamin A and calcium and the perception that mola is good for or protects the eyes have been well documented. METHODS: An integrated approach was conducted jointly by Bangladeshi and Danish institutions, linking human nutrition and fisheries. Activities included food-consumption surveys, laboratory analyses of commonly consumed fish species, production trials of carp-mola pond polyculture, teaching, training, and dissemination of the results. RESULTS: No decline in carp production and thus in income was found with the inclusion of mola, and increased intake of mola has the potential to combat micronutrient deficiencies. Teaching and training of graduates and field staff have led to increased awareness of the role of small indigenous fish species for good nutrition and resulted in the promotion of carp-mola pond polyculture and research in small indigenous fish species. The decline in accessibility, increase in price, and decrease in intake of small indigenous fish species by the rural poor, as well as the increased intake of silver carp (Hypophthalmichthys molitrix), the most commonly cultured fish species, which is poor in micronutrients and not preferred for consumption, are being addressed, and some measures taken by inland fisheries management have been discussed. CONCLUSIONS: The successful linking of human nutrition and fisheries to address micronutrient deficiencies has relevance for other countries with rich fisheries resources, such as Cambodia and countries in the Lake Victoria region of Africa.