一种杜香属植物茎叶水馏物的研究

对放置一年的一种杜香属植物茎叶水馏物进行了研究 .GC/MS测试表明 ,水馏物主成分为松油醇 (1 8.542 % ) ,2 ,5-二甲基 - 2 ,4-己二烯 (1 1 .50 0 % ) .色谱分离出 2 5个化合物 ,质谱鉴定出含量占 83.330 %的 1 6个组分 ,其中含氧化合物占 65.42 5% .并为监测其保持生物活性的时间 ,测出了其H -NMR指纹图 .

Fractionation of Heavy Metals in Sediments from Dianchi Lake,China

Fractionation of heavy metals in sediments can help in understanding potential hazards of heavy metals. The present study analyzed total concentrations and fractions of selected heavy metals （Cd, Cr, Cu, Pb, and Zn） in surface sediments from Dianchi Lake, Yunnan Province, China, as well as factors that may affect distributions of the various heavy metal fractions. Total concentrations of the heavy metals decreased in the order Zn 〉 Cu 〉 Pb 〉 Cr 〉 Cd. These heavy metals, except Cr, were much higher than their background levels, indicating that Dianchi Lake was polluted by Cd, Zn, Pb, and Cu. Cadmium occurred mainly as the non-residual fraction （sum of the HOAc-soluble, reducible, and oxidizable fractions） （97.6%）, and Zn （55.7%） was also predominantly found in the non-residual fraction. In contrast, most of the Cr （88.5%）, Pb （81.8%）, and Cu （59.2%） occurred in the residual fraction. Correlation analysis showed that total heavy metal concentrations, organic matter and reducible Fe were the main factors affecting the distributions of the various heavy metal fractions. In the Walhai section of Dianchi Lake （comprising 97% of the lake area）, the concentrations of Cd, Zn, Pb, and Cu in the non-residual fraction were significantly lower （P ≤ 0.01 or 0.05） than those of the Caohal section （3% of the lake area）. This indicated that potential heavy metal hazards in the Caohai section were greater than the Waihai section.

Effects of Wei Chang An pill(胃肠安丸) on enzyme activity and levels of vasoactive peptide and substance P in the small intestine of rats with compound diarrhea

OBJECTIVE:To investigate the regulatory effects of Wei Chang An Pill(WCAP) on enzyme activity and gastrointestinal hormones in the small intestine of rats with compound diarrhea.METHODS:Forty Wistar rats were randomly divided into a control,diarrhea model,and WCAP high,medium,and low dose groups.The control group was not treated,and the model group was administered intragastric distilled water.The WCAP groups were given WCAP suspension,80,60 or 40 mg · kg-1 · d-1,for 4 days.Stool properties were observed.After the experiment,thymus and spleen indices were measured,and the activities of lactate dehydrogenase(LDH),malate dehydrogenase(MDH),and disaccharidase(lactase) in the small intestinal mucous membrane,and levels of substance P(SP) and vasoactive peptide(VIP) in the colon were determined.RESULTS:Compared with the control group,thymus and spleen indices were significantly decreased,LDH,MDH,and disaccharidase activity in the small intestine was decreased,and SP and VIP levels in the colon were significantly increased inthe diarrhea model group.Compared with the model group,thymus and spleen indices were significantly increased,and LDH,MDH,and disaccharidase activity in the small intestine and SP and VIP levels in the colon were significantly decreased in theWCAP medium dose group.CONCLUSION:The diarrhea model rats exhibited pathological changes including atrophy of the thymus and spleen,decreased enzyme activity in the small intestine,and gastrointestinal hormone disturbance.WCAP can increase the activity of intestinal digestive enzymes and regulate gastrointestinal hormones,thereby relieving diarrhea.

Mo marine geochemistry and reconstruction of ancient ocean redox states

Molybdenum(Mo) proxies, including bulk concentration and isotopic composition, have been increasingly used to reconstruct ancient ocean redox states. This study systematically reviews Mo cycles and their accompanying isotopic fractionations in modern ocean as well as their application in paleo-ocean redox reconstruction. Our review indicates that Mo enrichment in sediments mainly records the adsorption of Fe-Mn oxides/hydroxides and chemical bonding of H2 S. Thus, Mo enrichment in anoxic sediments generally reflects the presence of H2 S in the water column or pore waters. In addition to the effect of euxinia, sedimentary Mo enrichment is related to the size of the oceanic Mo reservoir. Given these primary mechanisms for oceanic Mo cycling, Mo abundance data and Mo/TOC ratios acquired from euxinic sediments in geological times show that fluctuations of the oceanic Mo reservoir are well correlated with oxygenation of the atmosphere and oceans and suggest that oxygenation occurred in phases. Mo proxies suggest that Mo isotopes in strongly euxinic sediments reflect the contemporaneous Mo isotopic composition of seawater, but other processes such as iron-manganese(Fe-Mn) adsorption and weak euxinia can result in different fractionations. Diagenesis may complicate Mo enrichment and its isotopic fractionation in sediments. With appropriate constraints on the Mo isotopic composition of seawater and various outputs, a Mo isotope mass-balance model can quantitatively reconstruct global redox conditions over geological history. In summary, Mo proxies can be effectively used to reconstruct oceanic redox conditions on various timescales due to their sensitivity to both local and global marine redox conditions. However, given the complexity of geochemical processes, particularly the effects of diagenesis, further work is required to apply Mo proxies to ancient oceans.