银木种内化学类型研究

毛细管气相色谱／质谱／计算机联用仪器分析结果表明,在四川省成都市一人工种植的银木（Ｃｉｎｎａｍｏｍｕｍｓｅｐｔｅｎｔｒｉｏｎａｌｅ）种群中,其枝叶精油主要化学组成在各植株间存在很大差异,发现精油存在１,８－桉叶油素,樟脑,异丁香酚甲醇和９－氧代橙花叔醇等四个化学类型．除异丁香酚甲醚类型外,其余类型均为第一次报道．综观樟属其它种的化学类型研究可见,化学类型在樟属植物中普遍存在种内多型性和种间共性．     

Health Risk Assessments Based on Existing Data of Arsenic,Chromium, Lead,and Zinc in China's Air

Health risk assessments of As, Cr, Pb, and Zn in air in China were carried out from a national perspective. Concentrations of the four metals in air were gathered from published literature. Health risk assessment models recommended by the U.S. Environmental Protection Agency (USEPA) were applied to quantitatively characterize risk values of the metals by considering different age groups. Results showed that the atmospheric metal concentrations in most regions of China were lower than their inhalation reference concentrations provided by the USEPA, or limited values provided by China. Non-carcinogenic hazard values of the four metals in different regions of China were all lower than 1, indicating no or low non-carcinogenic hazard. However, the probabilities of carcinogenic risk values for As and Cr exceeding the acceptable value (1.0E-05) were 9% and 10% on a national scale, respectively. Some regions, such as Shanxi, Chongqing, Liaoning, and Shanghai, should be studied in more detail. Despite uncertainties, the results of this study provide information on the health risk of As, Cr, Pb, and Zn in air in China.     

Transmembrane Exchange of Hyperpolarized 13C-Urea in Human Erythrocytes: Subminute Timescale Kinetic Analysis

The rate of exchange of urea across the membranes of human erythrocytes (red blood cells) was quantified on the 1-s to 2-min timescale. ¹³C-urea was hyperpolarized and subjected to rapid dissolution and the previously reported (partial) resolution of ¹³C NMR resonances from the molecules inside and outside red blood cells in suspensions was observed. This enabled a stopped-flow type of experiment to measure the (initially) zero-trans transport of urea with sequential single-pulse ¹³C NMR spectra, every second for up to ∼2 min. Data were analyzed using Bayesian reasoning and a Markov chain Monte Carlo method with a set of simultaneous nonlinear differential equations that described nuclear magnetic relaxation combined with transmembrane exchange. Our results contribute to quantitative understanding of urea-exchange kinetics in the whole body; and the methodological approach is likely to be applicable to other cellular systems and tissues in vivo.     

Extraction and retrieval of potassium from water hyacinth (Eichhornia crassipes)

Studies were carried out on extraction and retrieval of potassium from water hyacinth (Eichhornia crassipes). The stem and leaf were subjected to 13 treatments. The highest rate of K removal following HCl treatment was 69.7% K. Most effective removal of suspended organic substances, Ca2+ and Mg2+ were achieved at pH approximately 13, when 88.0% of K remained in filtrate. Maximum K in precipitate following this step was achieved with tartaric acid additions at n(C4H6O6)/n(K+) of 1.72 when precipitating at 4 degrees C for 3h, which resulted in 72.3% of K removal from the solution. Over the entire process, 44.3% of K in the dried stem-leaf sample of water hyacinth was retrieved in the form of KC4H5O6. This process demonstrated the potential for use of water hyacinth as a resource of potassium to produce potassium salts and provide a valuable end use for the plant, which could be highly invasive in aquatic ecosystems.     

乌桕梓油和桕脂的脂肪酸组成研究

运用色谱-质谱分析方法,鉴定乌桕梓油和桕脂的脂肪酸成分.分析结果,野生乌桕和栽培乌桕在脂肪酸组成上相同;梓油除了含常见的亚麻酸、亚油酸、油酸、棕榈酸和硬脂酸之外,还含有不常见的2,4-癸二烯酸和8-羟基-5,6-辛二烯酸;桕脂含棕榈酸、油酸、硬脂酸和亚油酸.两者的主要差异在于蜡质层厚度和核的大小及其油脂含量的不同.     

Some aspects of the growth of Gracilaria tenuistipitata in pond culture

The effect of temperature, salinity, nitrogen, culture density and depth on the growth of Gracilaria tenuistipitata were investigated between April 1985 and March 1986 in outdoor ponds in Guangxi Province, South China. The mean annual growth rate was 2.4% per day. Under favourable temperatures of 20–30 °C, daily growth rate may reach as high as 3.3%. Salinity had an obvious effect on growth and photosynthesis and growth peaked at 21, with a broad plateau between 7–27. Growth experiments showed that a total nitrogen (NH₄-N plus NO₃-N) concentration of 4 M was sufficient to enable the plants to maintain a daily growth rate of 2.7%. The best growth of the plant was obtained at a culture density of 0.5–1 kg m^–2 and a culture depth of 30 cm in the pond.     

Effects of altered photoperiod on circadian clock and lipid metabolism in rats

Disruption of circadian clock timekeeping due to changes in the photoperiod enhances the risk of lipid metabolism disorders and metabolic syndrome. However, the effects of altered photoperiods on the circadian clock and lipid metabolism are not well understood. To explore the effects of altered photoperiods, we developed a rat model where rats were exposed to either short-day or long-day conditions. Our findings demonstrated that altered photoperiods mediated circadian clocks by partly disrupting rhythmicity and shifting phase values of clock genes. We also showed that compared to long-day conditions, rats under short-day conditions exhibited more photoperiodic changes in a variety of physiological outputs related to lipid metabolism, such as significant increases in serum triglyceride (TG), high-density lipoprotein, and leptin levels, as well as increased body weight, fat:weight ratio, and hepatic TG levels. These increments were gained possibly through upregulated expression of forkhead box O1 (FoxO1), which partly mediates the expression of peroxisome proliferator-activated receptorα (PPARα) to increase the expression of phosphoenolpyruvate carboxykinase (PEPCK), peroxisome proliferator-activated receptor-g coactivator-1β (PGC1β), and fatty acid synthase (Fasn). In addition, the oscillation rhythms of FoxO1, PEPCK, PGC1β, and Fasn expression levels in the livers of rats exposed to a short-day photoperiod were more robust than those exposed to a long-day photoperiod. These findings suggest that a change in photoperiod can partly disrupt the circadian rhythmcity of clock genes, impair lipid metabolism, and promote obesity.     

中国芦荟资源的利用和保护

８０年代资源调查结果表明,中国芦荟〔ＡｌｏｅｖｅｒａＬ．ｖａｒ．ｃｈｉｎｅｎｓｉｓ（Ｈａｗ．）Ｂｅｒｇｅｒ〕在广东雷州半岛西南、海南岛西北部火山灰地区资源量较大,分布较集中,但由于围垦开荒已受到较大破坏,为了有效保护和开发利用中国芦荟资源,在广东雷州半岛分步建立１３ｈｍ２种植基地。通过中国芦荟与翠绿芦荟（ＡｌｏｅｖｅｒａＬ．）主要化学组成的比较,表明中国芦荟同样可作为药品、化妆品、食品饮料工业的原料。已研制出４个系列１１种中国芦荟产品,与此同时为配合在食品、药物方面的开发,还进行了三个阶段的毒理试验,结果表明中国芦荟原汁无毒、未发现致畸、致突变作用,可作为食品新资源开发利用