不同碳源对虎奶菇菌核蛋白质营养价值的影响

测定了四种碳源对虎奶菇菌核蛋白质营养价值的影响。结果表明，以玉米淀粉为碳源，虎奶薅菌蛋白质的化学评分，必需氨基酸指数，生物价和营养指数分别为11．63、69．80、64．40和9．98，均居四种参试碳源的第一位；氨基酸评分和氨基酸比值系数分分别为14．55和12．45，均居四种参试碳源的第二位，这些结果证实，以玉米淀粉为碳源，虎奶菇菌核蛋白质营养价值高，值得推广应用。     

Expression of undulin in experimental rat liver fibrosis

AIM: To observe the expression of undulin (Un) in liver tissue and to clarify the diagnostic significance of serum Un in experimental rat liver fibrosis. METHODS: Rat liver fibrosis was induced by carbon tetrachloride. The expression of Un in liver tissue was detected by immunohistochemical method. Serum Un levels was measured by enzyme immunoassay. RESULTS: Expression of Un increased in fibrotic liver than normal liver, and it was mainly distributed in portal tract stroma, central veins and fibrotic septa in fibrotic liver. Also, the level of serum Un was significantly higher in fibrotic liver than normal liver. CONCLUSION: These data suggest that Un should be a component of the hepatic extracellar matrix, and its expression could be increased greatly in fibrotic rat liver. Serum Un levels may be used as an indicator in liver fibrosis diagnosis.     

不同施氮量对甜椒碳、氮营养分配的影响

 通过水培试验，利用 N和”C双示踪技术研究了不同施氮量对甜椒结果期碳、氮营养分配的影响 结果表明：结果前期吸收的 N在低氮(NO3一N 2．5 mol·L～，NH4+一N 0．25 mol·L )营养处理下分配于果实中的比率高于中氮(NO；一N 5．0 mol·L～，NH —N 0．5 mol·L )和高氮(NO；一N 11．0 mol‘L～，NH4+一N 1．0 mol·L )营养处理。氮水平制约着 N在各器官中的分配和再运转，很少影响”C在器官间的分配，但却制约着”C的运转和再分配，表现为中氮营养最有利于 C向果实中的再运转。碳氮营养平衡有利于碳素向生殖器官的运转和积累，这是低氮营养产量前高后低，高氮营养产量前低后高，中氮营养前后期产量均较高的根本原因。     

Hyperglycaemia in transition dairy cows: Effects of lactational stage and conjugated linoleic acid supplementation on glucose metabolism and turnover

Supplementing conjugated linoleic acid ( CLA ) is supposed to spare glucose due to the milk fat‐depressing effect of the trans ‐10, cis ‐12 CLA isomer, and allows repartitioning nutrients despite an energy deficiency in early lactation. However, there is still a lack of knowledge in terms of the dynamic pattern of the glucose turnover in transition dairy cows. We hypothesized that dairy cows supplemented with CLA have an altered rate of glucose turnover and insulin sensitivity during early lactation. We conducted three consecutive hyperglycaemic clamps (HGC ) in weeks ?2, +2 and +4 relative to parturition in Holstein cows supplemented daily either with 70 g of lipid‐encapsulated CLA (6.8 g trans ‐10, cis ‐12 and 6.6 g of the cis ‐9, trans ‐11 CLA isomer; CLA ; n  = 11) or with 56 g of control fat ( CON ; n  = 11). From week ?3 up to week +4 relative to parturition, milk yield and dry matter intake (DMI ) were recorded daily, while body weight (BW ) and milk composition were obtained once weekly. Blood samples were taken once weekly and every 30 min during the HGC . Plasma was analysed for concentrations of glucose, fatty acids (FFA ), beta‐hydroxybutyrate (BHB ), insulin, triglycerides and cholesterol. The CLA supplementation did not affect performance and metabolic parameters except for BHB and cholesterol. Furthermore, insulin concentrations and insulin sensitivity were affected by treatment. During the HGC in early lactation, insulin response was lower and decrease in FFA and BHB greater compared with the HGC in week ?2 although glucose target concentration achieved during the steady‐state period was similar for all three HGC . Our findings in terms of insulin and cholesterol suggest that body reserves are preserved through CLA feeding without restraining animal's performance. Furthermore, CLA effects on cholesterol and triglyceride concentrations indicated beneficial effects on hepatic lipid export contributing to an improved efficiency of prevailing metabolites in circulation.     

碳纳米管的酸化处理对碳纳米管/聚氨酯复合材料微观结构及性能的影响

对多壁碳纳米管进行酸化处理,并采用原位聚合法制备了碳纳米管/聚氨酯复合材料。利用X射线光电子能谱分析(XPS)、电子扫描显微镜(SEM)、动态力学分析(DMA)研究了碳纳米管酸化与否对复合材料性能的影响。结果表明,碳纳米管经酸化处理后产生了羧基,碳纳米管的原位加入使得复合材料的储存模量和玻璃化转变温度都有所提高,而且经过酸化的碳纳米管对聚氨酯材料的改性要比未酸化碳纳米管对聚氨酯材料的改性效果更为显著。     

Earthworms increase soil microbial biomass carrying capacity and nitrogen retention in northern hardwood forests

Earthworms have been shown to produce contrasting effects on soil carbon (C) and nitrogen (N) pools and dynamics. We measured soil C and N pools and processes and traced the flow of ¹³C and ¹⁵N from sugar maple (Acer saccharum Marsh.) litter into soil microbial biomass and respirable C and mineralizable and inorganic N pools in mature northern hardwood forest plots with variable earthworm communities. Previous studies have shown that plots dominated by either Lumbricus rubellus or Lumbricus terrestris have markedly lower total soil C than uncolonized plots. Here we show that total soil N pools in earthworm colonized plots were reduced much less than C, but significantly so in plots dominated by contain L. rubellus. Pools of microbial biomass C and N were higher in earthworm-colonized (especially those dominated by L. rubellus) plots and more ¹³C and ¹⁵N were recovered in microbial biomass and less was recovered in mineralizable and inorganic N pools in these plots. These plots also had lower rates of potential net N mineralization and nitrification than uncolonized reference plots. These results suggest that earthworm stimulation of microbial biomass and activity underlie depletion of soil C and retention and maintenance of soil N pools, at least in northern hardwood forests. Earthworms increase the carrying capacity of soil for microbial biomass and facilitate the flow of N from litter into stable soil organic matter. However, declines in soil C and C:N ratio may increase the potential for hydrologic and gaseous losses in earthworm-colonized sites under changing environmental conditions.     

Oxygen isotope ratios of plant available phosphate in lowland tropical forest soils

Phosphorus (P) cycles rapidly in lowland tropical forest soils, but the process have been proven difficult to quantify. Recently it was demonstrated that valuable data on soil P transformations can be derived from the natural abundance of stable oxygen isotopes in phosphate (δ¹⁸O_P). Here, we measured the δ¹⁸O_P of soils that had received long-term nutrient additions (P, nitrogen, and potassium) or litter manipulations in lowland tropical forest in Panama and performed controlled incubations of fresh soils amended with a single pulse of P. To detect whether δ¹⁸O_P values measured in the incubations apply also for soils in the field, we examined the δ¹⁸O_P values after rewetting dry soils. In the incubations, resin-P δ¹⁸O_P values converged to ∼3.5‰ above the expected isotopic equilibrium with soil water. This contrasts with extra-tropical soils in which the δ¹⁸O_P of resin-P matches the expected equilibrium with soil water. Identical above-equilibrium resin-P δ¹⁸O_P values were also found in field soils that did not receive P additions or extra litter. We suggest that the 3.5‰ above-equilibrium δ¹⁸O_P values reflect a steady state between microbial uptake of phosphate (which enriches the remaining phosphate with the heavier isotopologues) and the release of isotopically equilibrated cell internal phosphate back to the soil. We also found that soil nutrient status affected the microbial turnover rate because in soils that had received chronic P addition, the original δ¹⁸O_P signature of the fertilizer was preserved for at least eight weeks, indicating that the off-equilibrium δ¹⁸O_P values produced during microbial phosphate turnover was not imprinted in these soils. Overall, our results demonstrate that ongoing microbial turnover of phosphate mediates its biological availability in lowland tropical soils.     

低碳经济下绿色证券市场资源配置研究

随着经济高速发展,高耗能、高污染的问题日益严重,通过绿色证券资源配置可以达到低碳、环保的目的。该文分析了绿色证券市场的资源配置模式,并对中国绿色证券市场的现状进行了分析;最后从上市条件、制度和立法等方面对提高绿色证券市场资源配置效率提出了具体的对策。     

西方国家碳税收入使用政策比较及其启示

碳税收入使用政策是西方国家碳税制度设计的一项重要内容，其主要基于税收中性原则，将税收收入或投资于环保节能项目，或以税式支出方式降低纳税人负担，确保碳税收入的循环，实现节能减排的目标。在我国碳税制度设计的构想中，应借鉴西方国家税制经验，结合本国现实情况，科学合理地设计碳税收入使用政策，确保碳税调节功能的充分发挥，将碳税发展成培育战略性新兴产业的重要政策工具之一。