改进的非参数核估计预测上证指数

改进了单纯利用非参数核估计预测上证指数的方法。首先利用隐马尔科夫模型将数据分成两种状态,即正常状态和非正常状态。然后对正常状态的数据仍然使用非参数核估计进行预测,而对非正常状态的数据则结合支持向量机(SVM)进行预测。由于在较少数据预测问题中支持向量机模型预测具有较大的优势,从而使新的预测方法较以前的方法具有更好的预测效果。     

Active-learning versus teacher-centered instruction for learning acids and bases

The prevalence of the ideas of Year I undergraduate biology students about the consequences, causes and cures of the 'greenhouse effect' was determined using a closed-form questionnaire, and the results compared with a parallel study undertaken nearly 10 years ago. Many of the students in the present study were unaware of the potential effect of global warming on the distribution of crop pests, or that ground level ozone acts as a 'greenhouse gas'. Prevalent misconceptions were that global warming is caused by increased penetration of solar radiation, that it is connected with holes in the ozone layer, that it would result in increased skin cancer, and that use of unleaded petrol would reduce it. There appeared to be a general conflation of thinking about global warming and ozone layer depletion. Despite an increased certainty about the existence and effects of global warming among experts, the results are broadly similar to, and certainly no better than, those obtained with an equivalent group of students in a previous study, suggesting that despite media publicity and inclusion of the issue of global warming in the formal curriculum, insecure knowledge and misconceptions persist.     

BP Group and CAS institute to co-establis an energy lab in Dalian

The CAS Dalian Institute of Chemical Physics （DICP） and BP Group will join efforts to set up an Energy Innovation Laboratory （BP-DICP ElL） at DICP. The agreement for the new initiative was signed by DICP Director ZHANG Tao and BP Group Vice President Tony Meggs on 5 December, 2007 in Dalian.     

AMINO ACIDS' PROTECTIVE EFFECTS ON EXPERIMENTAL ACUTE RENAL FAILURE

This study was carried out to elucidate the nephroprotective effects from a mixture of 8 L-amino acids and the possible mechanism of protection by this amino acid mixture. Acute renal failure model was induced by an intravenous administration of 10 mg/kg cisplatin to male Sprague-Dawley rats. A mixture of 8 L-amino acids or 0.9% saline was infused at a rate of 2 ml/h for 3 h, starting with a 2 ml bolus injection before cisplatin administration. Amino acids showed no acute effect on renal morphology. The infusion of a mixture of 8 L-amino acids increased GFR by 85% in control rats. The abnormalities of urine sodium and potassium excretion caused by cisplatin were markedly attenuated by the administration of the amino acid mixture. With the infusion of this amino acid mixture, cisplatin-induced abnormal state 4 respiration returned to control levels and the depressed state 3 respiration, respiratory control ratio and carbonyl cyanide p-trifluoromethoxyphenyl hydrazone-uncoupled respiration were ameliorated remarkably. A mixture of 8 L-amino acids showed marked nephroprotection against cisplatin-induced acute renal failure in rats and might function through augmentation of the cisplatin-injured renal mitochondrial electron transport-oxidative phosphorylation sequence, probably via stabilizing the membrane (including inner mitochondrial membrane) protein tertiary structure. In addition, this amino acid mixture remarkably increased GFR and decreased urine sodium excretion in rats.     

磺酰化氮取代氨基酸配合物的合成与结构研究进展

本文综述了磺酰化氮取代氨基酸配合物的合成、配位结构方式的研究进展。     

Degradation of collagen in parchment under the influence of heat-induced oxidation: Preliminary study of changes at macroscopic,microscopic, and molecular levels

This paper examines the impact of heat-induced oxidation for new and historical parchment with the purpose of improving diagnostic tools for use in practical parchment conservation. Oxidation was generated by heat aging at 120°C in a dry oven for 24, 48, and 96 hours, respectively. The degradation was assessed on all samples at macrolevel by measuring color changes, at microlevel by measuring the shrinkage temperature as well as by performing a visual assessment of the fibers’ morphology and determining the amount of damaged fibers, and finally, at molecular level where amino acid analysis was used to reveal changes in the oxidized collagen. The study shows that the heat-induced oxidation leads to significant color changes, decrease in hydrothermal stability, as well as changes in the amino acid composition. Surprisingly, the results show that the historical parchment is more sensitive towards dry heat oxidation on a molecular level than is the new parchment. Furthermore, for the first time, we can show that physical damage reflected in the morphological characteristics of fibers can be attributed to oxidation by dry heat.     

Assessment of indoor air quality and the risk of damage to cultural heritage objects using MEMORI® dosimetry

Air pollution is one of the environmental influences that degrade cultural heritage objects situated indoors. Other essential influences, such as temperature, relative humidity, and light are often well monitored. The presence of air pollutants is less often measured or included in risk assessment. The MEMORI^® technology presented in this paper was developed as a tool for easy measurement and assessment of the general risk of degradation of heritage objects situated indoors due to indoor exposure to air pollutants. MEMORI dosimetry was performed in locations belonging to English Heritage and Tate (both located in London) and the National Archives of Norway in Oslo, to assess air quality. The related damage risk for collection objects and the protection offered by display and storage designs was assessed. A high level of acidic effect was observed inside a number of showcases, and a high level of oxidizing effect was observed in some room locations. Relatively simple mitigation measures, such as constructing tightly sealed showcases using low emitting materials, installing active carbon absorbing media inside a ‘microclimate’ frame, and using cardboard storage boxes for paper, significantly improved air quality. Overall, implementation of such measures is likely to improve the preservation of objects and reduce conservation costs.     

山茶和油茶种子中脂肪酸的分析

[目的]了解山茶和油茶种子中脂肪酸的组成和含量.[方法]气相色谱法测定山茶和油茶种子中脂肪酸的组成和含量.[结果]两种种子都含有4种脂肪酸:棕榈酸(8.45%和8.49%)、硬脂酸(2.67%和1.84%)、油酸(79.92%和81.62%)、亚油酸(8.95%和8.05%).[结论]油酸在山茶和油茶种子中的含量均很高.     

金花茶组培苗核酸的测定

以金花茶鲜幼叶为材料,经有机溶剂、酸等处理,除去色素、脂类、多糖类及蛋白质等。用HCIO_4提取RNA和DNA,紫外分光光度法测定其含量。结果表明:不同物种之间核酸含量不同,而组培苗与原种之间核酸含量基本相同,它可以作为组培苗遗传稳定性研究指标之一。     

Colorectal cancer cell growth inhibition by linoleic acid is related to fatty acid composition changes

Polyunsaturated fatty acids (PUFAs) possess anti-cancer action both in vitro and in vivo. In the present study, we detected cell viability with methyl thiazolyl tetrazolium (MTT) assay and cell membrane permeability with propidium iodide (PI) fluorescence dyeing, and calculated cell membrane fluidity change as fluorescence anisotropy. Fatty acid content in cells was measured by gas chromatography/mass spectroscopy (GC/MS), and the relationship between fatty acid composition and cell viability was studied. We observed that n-6 PUFA linoleic acid (LA) inhibited tumor cell growth at high concentrations (≥300 μmol/L), while low concentrations (100–200 μmol/L) seemed to promote cell proliferation. Analyses of cell membrane permeability, cell membrane fluidity, and cell fatty acid composition suggested that the anti-cancer action of LA could be related to changes in the ratio of n-6 to n-3 PUFAs. We observed that pre-incubation of cancer cells with 100 μmol/L LA for 24 h enhanced cell sensitivity to the cytotoxic action of LA, whereas undifferentiated cell line LoVo seemed to have a distinct path in LA-induced death. These results showed that one of the mechanisms by which supplementation of LA induces cancer cell death could be altering the ratio of n-6/n-3 PUFAs, and this may be related to cell differentiation status.