Brain myelination in rats treated with ionizing radiation in utero

Abstract

Effects of ionizing radiation on brain myelination and some physical development parameters were studied in laboratory rats (Fisher F‐344 inbred strain). Rats were treated with three different doses of radiation (150 rad, 15 rad, and 6.8 rad) delivered on the 20th day of prenatal life. Exposure to 150 rad reduced body, brain, ovary, kidney, heart and spleen weights. Prenatal exposure to 150 rad of radiation reduced the cerebral cortex weight by 22 percent at 30 days of age, and 20 percent at 52 days of age which caused a reduction in cerebral cortex myelin content by 20 and 23 percent at the ages of 30 and 52 days respectively. This dose did not affect the myelin content of the cerebellum or the brain stem, or the myelin concentration (mg myelin/g brain tissue) of the cerebral cortex, cerebellum, and the brain stem. The cerebral cortex weight of the 15 rad treated rats was reduced at the age of 30 days. Exposure to 15 rad, and 6.8 rad did not affect either the myelin content or the myelin concentration of these brain areas.     

The effects of partial mortality on the fecundity of three common Caribbean corals

The recent intensification of human disturbances in the Caribbean has increased the prevalence of partial mortality on coral colonies. Partial mortality can change colony size by directly shrinking colonies or by splitting colonies into fragments. A reduction in colony size can also adversely affect fecundity and fitness as internal resources shift away from reproduction toward colony maintenance. This study aimed to determine whether three Caribbean coral species, Siderastrea siderea, Montastraea faveolata, and Diploria strigosa, along the reef tract in Puerto Morelos, Mexico (20^o52′N, 86^o51′W), continued to dedicate resources to reproduction when colonies were fragmented to pre-maturation size. Contrary to expectations, eggs were found in colonies that were smaller than the maturation size and had been subjected to partial mortality. The continued dedication of resources toward reproduction, even in the smallest colonies, suggests that resource trade-offs away from reproduction are not as rigid as previously suggested in stressed corals.     

Do spotless starlings place feathers at their nests by ultraviolet color?

A considerable number of bird species carry feathers to their nests. Feathers’ presence in the nests has traditionally been explained by their insulating properties. Recently, however, it has been suggested that feathers carried to the nests by females of the spotted starling (Sturnus unicolor L.) could have an ornamental function based on their ultraviolet (300–400 nm) and human-visible longer wavelength (400–700 nm) coloration. In our population, 95.7% of feathers found inside next-boxes occupied by nesting starlings were rock dove fly feathers. Of these feathers, 82.7% were naturally positioned with their reverse side oriented toward the entrance hole and 42.4% of all found feathers were situated within the nest-cup. Here we experimentally assess the signaling function of ultraviolet coloration of feathers in nests of spotless starlings by providing nests with a number of pigeon flight feathers that were respectively treated on their obverse, reverse, both, or neither side with a UV blocker. Starlings placed 42.5% of the experimental feathers in the nest-cup irrespective of the UV block treatment. Orientation of feathers toward the entrance hole was not related with their ultraviolet radiation. However, feathers placed within the nest-cup were more likely found with their reverse side oriented toward the entrance hole confirming our correlative findings. These results suggest a minor role of ultraviolet coloration on feather location by spotless starlings.     

Propane as an Engine Fuel for Clean Air Requirements

Air pollutants in exhaust gas produced from LP-gas (propane) were studied using both laboratory engines and vehicles. The objective of the study was both to evaluate propane as a low-pollution fuel and to provide information on adjustment of engine parameters for advantageous use of propane as a low-pollution fuel. Variables in the study were air-fuel ratio (A/F), ignition timing schedule, and ambient temperature. Data comparable to that for propane relating A/F and ambient temperature to emissions are shown for natural gas and for gasoline.     

Ambio’s legacy on monitoring,impact, and management of acid rain: This article belongs to Ambio’s 50th Anniversary Collection. Theme: Acidification

Early studies published in Ambio showed large-scale acidification of lakes in southern Sweden and Norway from acid rain. These studies were important for delimiting various scientific issues and thus for eventually contributing to legislation, which reduced emissions of sulfur dioxide and nitrogen oxides and helped to mitigate this major environmental problem. Long-term studies and monitoring in Sweden and Norway and at Hubbard Brook Experimental Forest in New Hampshire helped guide this legislation in Europe and in the USA.     

Removal of emerging pollutant dibutylhydroxytoluene from water with CNT/TiO2 catalysts in a visible LED photoreactor

Environmental Science and Pollution Research - For the photocatalytic degradation of antioxidant 2,6-di-tert-butyl-hydroxytoluene (BHT), several TiO2-based composites have been prepared in MWCNT...     

Facile fabrication of hybrid titanium(IV) isopropoxide/pozzolan nanosheets (TnS-Pz) of high photocatalytic activity: characterization and application for Cr(VI) reduction in an aqueous solution

Environmental Science and Pollution Research - This paper presents the synthesis of a hybrid material through the use of natural pozzolan and titanium(IV) isopropoxide using the sol-gel method and...