The variable rotation period of the inner region of Saturn's plasma disk

We show that the plasma and magnetic fields in the inner region of Saturn's plasma disk rotate in synchronism with the time-variable modulation period of Saturn's kilometric radio emission. This relation suggests that the radio modulation has its origins in the inner region of the plasma disk, most likely from a centrifugally driven convective instability and an associated plasma outflow that slowly slips in phase relative to Saturn's internal rotation. The slippage rate is determined by the electrodynamic coupling of the plasma disk to Saturn and by the drag force exerted by its interaction with the Enceladus neutral gas torus.     

Biosynthesis and characterization of 14C-enriched flavonoid fractions from plant cell suspension cultures

A range of radiolabeled anthocyanins, proanthocyanidins, and other flavonoids were accumulated by cell suspension cultures of two plant species, ohelo (Vaccinium pahalae) and grape (a Vitis hybrid, Bailey Alicant A), after providing uniformly labeled [(14)C]sucrose to the medium. Approximately 15% of administered label was recovered in a series of flavonoid-rich fractions varying in composition. Anthocyanins, and monomers to oligomers of proanthocyanidins, were labeled effectively and characterized from both species. Most of the proanthocyanidin oligomers were based on the flavan-3-ols (+)-catechin and (-)-epicatechin. Cyanidin and peonidin glycosides were the dominant forms of anthocyanins in both species. Whereas the predominant form of flavonoids identified from ohelo cell cultures was proanthocyanidins, grape cell cultures produced mostly anthocyanins. The labeled phytochemicals were produced for use in subsequent in vivo animal feeding studies to gauge their bioavailability and accumulation in target organs.     

Germination of peanut kernels to enhance resveratrol biosynthesis and prepare sprouts as a functional vegetable

Bioactive benefits of resveratrol in the diets have attracted extensive interests of the public. Peanut is one of the potent natural sources of resveratrol. In this study, germination of peanut kernels to enhance resveratrol biosynthesis and preparation of sprouts as a functional vegetable was conducted. When the rehydrated kernels of three peanut cultivars were germinated at 25 degrees C and relative humidity 95% in dark for 9 days, resveratrol contents increased significantly from the range of 2.3 to 4.5 microg/g up to the range of 11.7 to 25.7 mug/g depending upon peanut cultivar. In comparison with the sprout components, resveratrol contents were highest in the cotyledons, slightly lower in the roots, and not detected in the stems. When the sprouts were heated in boiling water for 2 min, resveratrol contents varied in a limited range. Methanol extracts of the freeze-dried sprouts exhibited potent 1,1-diphenyl-2-picryl-hydrazyl scavenging activity and antioxidative potency against linoleic acid oxidation. These activities increased with an increase of germination time. After 9 days of germination, total free amino acid, sucrose, and glucose contents increased significantly while crude protein contents decreased and the large sodium dodecyl sulfate polyacrylamide gel electrophoresis protein molecules of the kernels were extensively degraded. From a practical viewpoint, it is of potency to prepare peanut sprouts as a functional vegetable.     

Participatory probabilistic assessment of the risk to human health associated with cryptosporidiosis from urban dairying in Dagoretti, Nairobi, Kenya

We carried out a participatory risk assessment to estimate the risk (negative consequences and their likelihood) from zoonotic Cryptosporidium originating in dairy farms in urban Dagoretti, Nairobi to dairy farm households and their neighbours. We selected 20 households at high risk for Cryptosporidium from a larger sample of 300 dairy households in Dagoretti based on risk factors present. We then conducted a participatory mapping of the flow of the hazard from its origin (cattle) to human potential victims. This showed three main exposure pathways (food and water borne, occupational and recreational). This was used to develop a fault tree model which we parameterised using information from the study and literature. A stochastic simulation was used to estimate the probability of exposure to zoonotic cryptosporidiosis originating from urban dairying. Around 6?% of environmental samples were positive for Cryptosporidium. Probability of exposure to Cryptosporidium from dairy cattle ranged from 0.0055 for people with clinical acquired immunodeficiency syndrome in non-dairy households to 0.0102 for children under 5?years from dairy households. Most of the estimated health burden was born by children. Although dairy cattle are the source of Cryptosporidium, the model suggests consumption of vegetables is a greater source of risk than consumption of milk. In conclusion, by combining participatory methods with quantitative microbial risk assessment, we were able to rapidly, and with appropriate 'imprecision', investigate health risk to communities from Cryptosporidium and identify the most vulnerable groups and the most risky practices.     

鸡转移因子最佳给予途径的确定

转移因子是 T淋巴细胞所释放的多种因子中的一种能够转移致敏信息的物质。它能够将供体细胞免疫功能转移给受体 ,增强受体免疫功能 ;而且可以通过 T细胞来调节 B细胞 ,改善其体液免疫功能 ,从而增强机体的抗病能力。这些作用已由哺乳动物转移因子所证明。用肉鸡脾脏制备转移因子已获得成功 [1] ,并用血凝抑制试验监测体液免疫效果 ,结果证明 ,鸡转移因子具有良好的生物活性 ,对 T细胞免疫和 B细胞免疫都具有积极作用 ,可促进机体产生良好的免疫效果 ,增强机体的免疫功能 [2 ]。以往转移因子的使用多采用注射方法 [3 ] ,但这在鸡场进行大规…     

应用辛酸硫酸铵法提纯兔抗鸡传染性法氏囊病IgG抗体

近年来,兔抗鸡传染性法氏囊病毒(IBDV)IgG抗体被广泛应用于鸡病诊断、免疫检测、治疗等方面。在提纯IgG过程中,为了保证除去绝大多数杂蛋白和白蛋白,保留大多数免疫球蛋白(Ig),同时又不影响IgG的生物活性,就需要一种好的提纯方法[1]。IgG的提取和纯化方法很多,但是各有优点与不足。单一辛酸法和硫酸铵法操作简单,但提取的IgG纯度不高。柱层析可获得高纯度的抗体,但成本很高,且回收率低[2]。本试验利用辛酸硫酸铵法对制备的兔抗     

鸡腺胃型传支的疾病模型确定Ⅱ.组织病理学的变化规律

用IBV腺胃型致病株(野毒株)人工接种1日龄雏鸡,同时,对鸡群人为地施以不同的应激因素,如降低温度、饥饿、不良通风和高饲养密度,使鸡感染发病.攻毒后每日观察两组鸡群的临床表现,并定期随机剖检,采集心、肝、脾、肺、肾、腺胃、肠道前段、肠道中段和后段等,固定于10%的中性福尔马林液中,石蜡切片,苏木素-伊红染色,显微镜下观察各组织器官的病理组织学变化.结果表明:攻毒后3～4日开始出现病理组织学变化,8～9日最为明显.主要组织病理学变化为腺胃炎和间质性肾炎,肺脏、肠道和肝脏也有一些变化,其他脏器的变化不太明显.     

鸡腺胃型传支的疾病模型确定 II. 组织病理学的变化规律

用 IBV腺胃型致病株 (野毒株 )人工接种 1日龄雏鸡 ,同时 ,对鸡群人为地施以不同的应激因素 ,如降低温度、饥饿、不良通风和高饲养密度 ,使鸡感染发病。攻毒后每日观察两组鸡群的临床表现 ,并定期随机剖检 ,采集心、肝、脾、肺、肾、腺胃、肠道前段、肠道中段和后段等 ,固定于 10 %的中性福尔马林液中 ,石蜡切片 ,苏木素 -伊红染色 ,显微镜下观察各组织器官的病理组织学变化。结果表明 :攻毒后 3～ 4日开始出现病理组织学变化 ,8～ 9日最为明显。主要组织病理学变化为腺胃炎和间质性肾炎 ,肺脏、肠道和肝脏也有一些变化 ,其他脏器的变化不太明显