Research on Effect of Four Natural Ultraviolet Light Absorbers on Photostabilization of Azadirachtin-A

This study examined the photostabilization of Azadirachtin-A （Aza-A） when exposed to ultraviolet light in the presence of some natural absorbers. Aza-A extract solutions with and without natural UV light absorbers in methanol were applied onto the surface of glass slides. At particular intervals, the remaining concentration of Aza-A was analyzed by HPLC. Using first-order kinetic equation, the dissipation half-life values （DT~0） for the degradation of Aza-A under ultraviolet radiation were obtained. It indicated that the addition of ferulic acid, gallic acid, and rutin provided moderate degree of photostabilization of Aza-A and that addition of aloin provided the best photostabilization of Aza-A, among these UV absorbers studied. Photostabilization of Aza-A by different UV light absorbers appears to be due to the competitive energy absorption of UV photons by the absorbers molecules. The dissipation half-life values of Aza-A after irradiation under ultraviolet light suggested that the addition of aloin （in 1 ： 1 mol ratio） can provide better photostabilization of azadirachtin molecule.     

How long is the day on Saturn?

Determining a planet's rotation period can be difficult if the planet lacks a solid surface. However, for planets with an internal magnetic field, emissions at radio wavelengths are modulated by the planet's rotation rate. The latest results from the Cassini spacecraft seem to indicate that Saturn's rotation rate has slowed down by 6 minutes since the Voyager 1 and 2 spacecraft flew by the planet in 1980 and 1981, but it is unclear whether a slowdown has in fact occurred. Future data collected by Cassini may be able to resolve the question.     

Effect of Light Quality on Tomato Fruit Qualities in Turning-Color Period

就不同光质对番茄果实转色期品质变化的影响,以各色荧光灯为光源,在人工控光条件下进行了探究。结果表明.在转色期间不同处理番茄果实的可溶性糖和有机酸含量均于处理后8-10d达最高,而Vc和番茄红素于处理后12d达最大。但不同光质处理间差异明显,红光处理8d后果实可溶性糖含量达到最高,处理后8-10dVc和番茄红素含量大幅度增加,成熟期比对照(白光)提前2d;红光和蓝光处理均提高了果实的可溶性糖及有机酸含量。各处理Vc含量以蓝光处理为最高,达123.7mg/kg(Fw),显著高于对照。番茄红素含量以红光处理最高,为89.6mg/kg(Fw)。黄光与对照之间差异不显著。绿光处理使番茄果实品质下降。     

Do the tropical freshwater fishes feed on aquatic fungi?

Consumption and processing of allochthonous plant litter by fishes is more common in tropical than temperate streams and rivers. Therefore, aquatic hyphomycetes in water (filtration), leaf litter (bubble chamber incubation), and fecal pellets (direct observation and inoculation to sterile leaf litter) of three dominant fishes belonging to the family Cyprinidae (Aplocheilus lineatus, Puntius filamentosus, and Rasbora daniconius) in two locations of the River Kali of the Western Ghats, India, were evaluated during postmonsoon season. Spores of 14 and 9 species of aquatic hyphomycetes were recovered on filtering water samples of Kaiga stream and Kadra dam with equal number of spores (32 spores · 100 mL⁻¹) and high Shannon diversity in Kaiga stream. In a bubble chamber incubation of leaf litter, 16 and 9 species were recovered from Kaiga stream and Kadra dam with high spore output (1122 versus 324 spores per mg dry mass) and high Shannon diversity in Kaiga stream. Both direct and indirect methods of examination of fecal pellets of fishes revealed more species in Kaiga stream than Kadra dam (4–7 versus 1–4 species). The spore release in leaf litter incubated with fecal pellets ranged from 2.3 to 98 spores·mg⁻¹·d⁻¹ with the highest Aplocheilus lineatus in Kaiga stream; while in Kadra dam, it was from 0.02 to 22.9 spores·mg⁻¹·d⁻¹ with the highest in Puntius filamentosus. The Shannon diversity of aquatic hyphomycetes was high in fecal pellets of Aplocheilus lineatus of Kaiga stream and Rasbora daniconius of Kadra dam. The top-ranked five species of aquatic hyphomycetes differed in water, leaf litter, and fish fecal pellets; however, Triscelophorus konajensis was common for all. All five top-ranked species of aquatic hyphomycetes in feces produced multicelled spores; thus, they were likely to have a better chance of viability through gut passage than single-celled spores. Preferential feeding, fungi in gut and feces, and survival and dissemination of spores by invertebrates and fishes with reference to aquatic hyphomycetes were discussed.