茶多酚对菜籽色拉油的抗氧化作用研究

在菜籽色拉油中添加ＴＰ,ＶｉｔＥ及ＴＰ＋ＣＡ,对油脂的ＰＯＶ和ＡＶ进行测定,结果表明,三者均有抑制色拉油ＰＯＶ和ＡＶ升高的作用。０．０１％￣０．０４％ＴＰ,０．０１％￣０．０４％ＶｉｔＥ及０．０１％￣０．０４％ＴＰ＋ＣＡ（０．０１％）对油脂ＰＯＶ的降低率依次为２８．４％￣３９．０％,０￣３９．４％及５０．４％￣７１．６％,而对ＡＶ的降低率则依次为０￣１３．５％,５．４％￣１０．８％及３．０％￣７．     

Photosynthesis, yield, and chemical composition of Tieguanyin tea plants (Camellia sinensis (L.) O. Kuntze) in response to irrigation treatments

Tieguanyin Oolong tea (Camellia sinensis (L.) O. Kuntze) is a name brand important commodity for Anxi county, Fujian province in China. Four-year-old tea plants at a tea plantation in Anxi were subjected to six different irrigation treatments (i.e. 5, 10, 15, 20, and 25 d irrigation intervals for T₁ to T₅ with a rate of 3.5 kg water per plant, plus a non-irrigated control). After 50 d of irrigation treatments, leaf water potential was −1.70, −2.34, −2.48, −2.89, −3.55, and −4.92 MPa for treatment T₁, T₂, T₃, T₄, T₅, and control, respectively. Leaf biomass yield increased by 32.8%, 21.9%, and 21.3% for T₁, T₂, and T₃, respectively, compared to control. The net photosynthesis (Pn), stomatal conductance (gs) and transpiration (E) decreased with irrigation interval increasing. Tea polyphenol (TP) and free amino acid (AA) decreased when the irrigation intervals were increased, but caffeine (CA) content apparently increased as the irrigation intervals were increased. To balance irrigation water demand and tea yield and quality, it is recommended that the irrigation interval should be set at 10 d with a rate of 3.5 kg water per plant for the optimal production in Anxi, Fujian province of China.     

Total phenolics and flavonoids and total antioxidant capacity in pistachio (Pistachia vera L.) nuts in relation to cultivars and storage conditions

The effects of cultivar, drying and storage conditions on total phenolics (TP), total flavonoids (TF) and total antioxidant capacity (TAC), measured with ferric reducing antioxidant power (FRAP) and radical scavenging capacity (2,2-diphenyl-1-picrylhydrazyl or DPPH) assays, of in-shell and unpeeled kernels of ripe pistachios were investigated. Drying was carried out at 45 °C for 34 h to approximately 5% moisture in kernels and storage of dried nuts in packaging atmosphere of dry air or N₂ at 1 °C or 20 °C for 6 or 12 months. At harvest, each cultivar showed its highest values for each measured variable and TP ranged from 16.2 to 7.9 mg gallic acid equiv. g⁻¹ d.w., TF from 7.2 to 3 mg catechin equiv. g⁻¹ d.w., FRAP from 132.5 to 58.8 μmol Trolox equiv. g⁻¹ d.w., and DPPH from 122.6 to 45.7 μmol Trolox equiv. g⁻¹ d.w. Drying resulted in losses in all cultivars that averaged approximately 14.2%, 14.1%, 11.9% and 12.2% for TP, TF, FRAP and DPPH, respectively, while during 12-month storage the corresponding losses in dried kernels averaged approximately 24.7%, 21.8%, 30.3% and 32.4%. Decreases in all measured variables were advanced by storage time, but prevented by low temperature and packaging in N₂ atmosphere. Among the studied cultivars, Pontikis, Aegina, Bronte and Cerasola showed higher values of TP, TF and TAC than Sirora, Kerman, Joley and Mumtaz in all cases, while Pontikis the highest in most cases. The effects of cultivar, time, temperature and packaging atmosphere during storage were all significant on TP, TF, FRAP and DPPH. Strong correlations were also found among the measured variables.     

茶叶对糖尿病的预防作用及其机理研究进展

随着人们生活水平的提高和饮食结构的变化,糖尿病的患病呈流行趋势,发病率逐年上升,预防和治疗糖尿病成为热门话题。现代科学证明茶叶作为健康饮品的同时对人体健康具有多方面的保健功效。本文回顾了茶叶在糖尿病预防方面已取得研究进展,综述了茶叶与糖尿病预防的相关流行病学和人体临床研究结果,并对茶叶预防糖尿病的机制进行了梳理。     

滇池流域双龙水库径流区人类活动的沉积物记录

采集滇池以南双龙水库的沉积物柱状样,对不同层的沉积物使用210Pb进行定年;分析了不同年代沉积物的粒度分布特征以及总有机碳(TOC)、总氮(TN)和总磷(TP)的含量;在此基础上,对环境指标与昆明市人口和经济发展数据关系进行了解析。结果表明:1双龙水库沉积物中值粒径的范围分布在4.07~6.90μm,平均值为5.71μm,沉积物中值粒径在1986年后突然减小;2沉积物中TOC、TN以及TP的含量的范围分别是8.78~26.15、1.59~3.26和0.23~0.47 g/kg,均值分别为11.30、2.01和0.33 g/kg。TOC、TN以及TP的含量在1998年之前相对稳定,而在1998年之后有较大程度增长;3利用有机指数和有机氮指标评价双龙水库沉积物污染的变化情况,结果发现两大指标有加速增长的趋势;4通过相关分析发现昆明市国内生产总值(GDP)与双龙水库沉积物有机指数和TOC含量存在较好的相关性。昆明市人口数量与双龙水库沉积物有机指数和TOC含量的相关性也较强。研究结果表明水体生态参数受到社会经济指标的显著影响,人类活动是近几十年影响双龙水库水质的主要因素。     

Application of Mobile IP in VPN

VPN is a technology that realizes the security transmission of private information through the public network. As one of key technologies, tunnel technology resolves the mobility problem of mobile nodes. Firstly, L2TP and IPSec have been compared based on these two tunnel principles introduction of VPN. Secondly the advantages of IPSec in security have been introduced. Then, the problems of mobile host and two models of tunnel in VPN have been introduced. Lastly, the advantages of utilizing the mobile IP to resolve the problem of mobile host have been analyzed, and this technology has been compared with VPDN.     

锡山地区河网入贡湖污染负荷计算

由于经济的高速发展,锡山地区产生大量污水排入河网,使得河网水环境不断恶化，进而对贡湖水质变化产生影响。通过建立适合锡山地区河网流态的水量水质模型，计算分析了该地区河网污染物（TP）排入贡湖的时间和空间变化规律。同时论证了望虞河对这种变化的贡献，为提高引江济太工程效益提供技术支撑。     

Polyphenolic compounds and antioxidant properties in mango fruits

Fruit of eight mango genotypes were evaluated for antioxidant potential by several biochemical assays (DPPH, ABTS, ORAC, FRAP, SASR and MCC) and tested for their polyphenol composition and vitamin C contents. The significance analysis demonstrated that the antioxidant capacity of Tainong 1 fruits were significantly higher than that of other genotypes, which was about 2.1–6.3-fold higher than Guifei assayed in ABTS, DPPH, ORAC and FRAP methods. The total polyphenols and flavonoids contents showed a great variety amongst mango genotypes and highly correlation with the total antioxidant capacity. It is concluded that significant genotypic difference exists in the total antioxidant capacity of mango fruits. Both total polyphenols and flavonoids are major contributors to the total antioxidant capacity in mango fruit.