Bai Lianyang

Rapid Visual Detection of Calcium Ions Using Glutathione Functionalized Gold Nanoparticles

In this paper, glutathione (GSH)-capped gold nanoparticles (GSH-GNPs) were prepared in water media and used for the colorimetric assay of Ca2+. GSH could quickly bind onto the GNP surfaces through its –SH group and the cross-linking of GSH-capped GNPs could be quickly achieved by chelation by its functional groups (–NH2 and–COOH) upon the addition of Ca2+. Color changes were observed from red to blue (or purple) within minutes with the increased concentration of Ca2+, in response to surface plasmon absorption of dispersed and aggregated nanoparticles. Using this colorimetric sensor, the concentration of Ca2+ was determined with a limit of detection low than 1×10−7 M by the naked eye and could further be monitored by a UV-vis spectrometry easily. The possible mechanism of the aggregated GSH-GNPs was discussed by the addition of ethylene diaminetetraacetate (EDTA) and Ca2+ in different orders.

Rapid, Sensitive and Selective Detection of Ametryn Using Gold Nanoparticles as Colorimetric Probes

The purpose of this paper is to develop a sensitive and low cost optical sensor for screening ametryn using bare gold nanoparticles (Au NPs). Based on the distance-dependent optical properties of Au NPs, the presence of ametryn could rapidly induce the aggregation of gold nanoparticles, thereby resulting in red-to-deep blue color change. The concentration of ametryn was determined with a limit of detection (LOD) lower than 1×10-6 M by the naked eyes and could be further monitored by a UV-vis spectrometer easily. The highest selectivity was achieved in comparison with other eleven pesticides with similar molecular structure, and the possible underlying mechanism was investigated by the simultaneous addition of tiopronin and ametryn in Au NPs solution.

BIONOMIC OF CAMPOLETIS CHLORIDEAE (HYM:ICHNEUMONIDAE)AS A PARASITOID OF THE COTTON BOLLWORM HELICOVERPA ARMIGERA(LEP:NOCTUIDAE)*

Abstract The bionomics of Campoletis chlorideae and the regularity of its seasonal fluctuations were studied in Changsha district, Hunan province. Field investigation indicated that there were ten generations of C. chlorideae a year, of which seven occurred in cotton fields. Three peaks of cotton bollworm parasitization by C. chlorideae were observed, early May to late June, mid August to early September, mid September to mid October respectively. One peak occurred in tomato and tobacco fields, the other two in cotton fields. The parasitization rate ranged from 25. 1 % ‐63. 1 %. The total development time from egg to adult ranged from 13. O days at 32°C to 75. 5 days at 11. 6 °C. Each wasp could parasitize the 5–23 second instar larvae of tobacco caterpillar. C. chlorideae could parasitize the cotton bollworm, beet armyworm and tobacco caterpillar, but preferred the cotton bollworm larvae. C. chlorideae could parasitized 1st‐ 3rd instar larvae of the tobacco caterpillar, but seldom parasitzed 4th ‐ 6th instar larvae. Moreover, C. chlorideae preferred second instar larvae. Theoretical models for developmental speed, adult longevity and the influence of temperature were proposed. The overwintering of C. chlorideae Uchida was also discussed. Moreover, methods for utilization of C. chlorideae Uchida in crop protection were presented and the bionomics of Curyoletis chlorideae in both the Yangtze River Valley and Yellow River Valley were compared.

Using an Ionic Liquid as the Porogen in the Preparation of Methacrylate-Based Monolith in Capillary Liquid Chromatography

A methacrylate monolith was prepared inside a fused silica capillary column by microwave irradiation using an ionic liquid (1-hexyl-3-methylimidazolium tetrafluoroborate) as the porogenic solvent. Baseline separation of the model analytes, including thiourea, benzene, toluene, ethylbenzene and propylbenzene, was achieved by capillary liquid chromatography, with the lowest theoretical plate height of 26.83 µm for benzene. In addition, we also investigated the effects of the acetonitrile content in the mobile phase, flow rate on retention time, resolution and total porosity. The morphology of methacrylate monolith was studied by scanning electron microscopy.

Highly Selective and Sensitive Colorimetric Sensor of Cyromazine Based on Gold Nanoparticles

In this paper, a highly sensitive and low cost optical sensor of cyromazine was prepared and used to the colorimetric detection using bare gold nanoparticles (Au NPs). Based on the distance-dependent optical properties of Au NPs, the presence of cyromazine could rapidly induce the aggregation of gold nanoparticles, thereby resulting in red-to-deep blue color change. The concentration of cyromazine was determined with a limit of detection (LOD) lower than 1 mg/L by the naked eyes and the sensitivity could be enhanced by the adjustment of ion strength and pH. The highest selectivity was obviously achieved with an absorption ratio (A640/A520) greater than 0.9. Moreover the possible underlying mechanism was discussed.

Effects of coumarins on cold resistance of rice seedlings

The effects of coumarins have been studied on seedling rate,stem and leaf dry weight and root dry weight of the tested rice,as well as defense enzymes,soluble protein content,chlorophyll content and proline content with coumarins (peucedanocoumarin Ⅲ,PeucedanocoumarinⅡ,pteryxin) (1,5,10,50,100 mg/L).The coumarin compounds have been used to treat the early rice combination Peiliangyou500 with low temperature stress of(5±1) ℃.The results showed that three coumarin compounds could make seedling rate,stem and leaf dry weight and root dry weight of the tested rice significantly higher than control,and the effect of 50 mg/L was the best.50 mg/L coumarin compounds made peroxidase,superoxide dismutase,catalase active and soluble protein content,chlorophyll content.Proline accumulation also increased under low temperature stress.