No abstract

This study was designed to assay the estrogenic activities and the antioxidant potential of ethanol extracts from the herbal dietary supplement black cohosh (Cimicifuga racemosa) relative to the natural phytoestrogen genistein. The in vivo mechanisms of action of these two natural products have not been completely elucidated, and Japanese medaka (Oryzias latipes) provides a useful organism for initial in vivo screening of natural products. While both genistein and estradiol altered ovarian and testicular steroid release and decreased circulating testosterone levels in males, neither black cohosh total extract (75-30,000 ng/fish), cimiracemoside A, 25-O-methyl-cimigenoside, actein, nor 26-deoxy-actein caused any differences in estrogenic activity compared to control fish. To assess antioxidant potential, animals were treated with natural products then challenged with 2-acetylaminofluorene (2-AAF) to induce lipid peroxidation (LPO) in the liver. Neither the total ethanol extracts from black cohosh nor its individual components showed an inhibitory effect in 2-AAF induced LPO. However, genistein manifested potent antioxidative activity in the LPO assay, with similar potency to a high dose of á-tocopherol. In contrast to genistein, black cohosh did not exhibit traditional estrogenic effects nor significant in vivo anti-oxidant potential in this fish model system.

This study was designed to assay the estrogenic activities and the antioxidant potential of ethanol extracts from the herbal dietary supplement black cohosh (Cimicifuga racemosa) relative to the natural phytoestrogen genistein. The in vivo mechanisms of action of these two natural products have not been completely elucidated, and Japanese medaka (Oryzias latipes) provides a useful organism for initial in vivo screening of natural products. While both genistein and estradiol altered ovarian and testicular steroid release and decreased circulating testosterone levels in males, neither black cohosh total extract (75-30,000 ng/fish), cimiracemoside A, 25-O-methyl-cimigenoside, actein, nor 26-deoxy-actein caused any differences in estrogenic activity compared to control fish. To assess antioxidant potential, animals were treated with natural products then challenged with 2-acetylaminofluorene (2-AAF) to induce lipid peroxidation (LPO) in the liver. Neither the total ethanol extracts from black cohosh nor its individual components showed an inhibitory effect in 2-AAF induced LPO. However, genistein manifested potent antioxidative activity in the LPO assay, with similar potency to a high dose of á-tocopherol. In contrast to genistein, black cohosh did not exhibit traditional estrogenic effects nor significant in vivo anti-oxidant potential in this fish model system.

Investigating the wind-induced vibration response of the greenhouse structure, and the wind pressure distribution on its surface takes on a critical significance when the main structure is under large wind loads. A computational fluid dynamics-based study was conducted, and wind tunnel tests were performed to study the wind pressure distribution on the surface of the greenhouse structure. First, three types of greenhouses, including Venlo, Round-arch, and Saw-tooth type greenhouses, were selected as the design models for the study. In addition, the double-span, four-room structure model was built to explore the wind pressure distribution and the extreme wind pressure coefficient on the greenhouse surface for 13 (0°–180°, every 15°) directions of the wind direction to obtain the wind load characteristics in the greenhouse surface under different conditions. The results of the wind tunnel tests were consistent with those of the simulations, with the maximum wind pressure in the X-direction occurring at 30°-wind and the maximum wind pressure in the Y-direction at 75°-wind. The maximum negative wind pressure acting locally on the roof of the greenhouse was twice the maximum positive pressure acting on the windward side of the greenhouse. Accordingly, it is necessary to strengthen the structure in regions sensitive to wind direction with significant response to wind.

In-situ TiB 2 particles reinforced 2014Al alloy matrix composite was prepared using an exothermic reaction process with K 2 TiF 6 and KBF 4 salts. The age-hardening behaviors of in-situ TiB 2 /2014Al composites were studied using Vickers-hardness measurement, DSC and TEM. The results indicated that TiB 2 particles had a considerable effect on the aging response of 2014Al alloy matrix in the composite. Due to the introduction of TiB 2 particles, the time to achieve peak hardness in the composite is shorter at three aging temperatures compared with that of 2014Al alloy. While the age-hardness ef ciency of the composites was lower than that of 2014Al alloy. Formation of G.P. zones was suppressed in composite, which was believed to be due to the introduction of vast particle-matrix interfaces that acted as a sink for vacancies during quenching. Moreover, TiB 2 particles caused increase in thermal-diffusion activation energy of θ ′ phase during aging, which made the precipitation of θ ′ phase more dif cult. And the number and size of precipitates in the composite were relatively less and smaller than that of 2014Al alloy.