超声法提取山楂果实中总黄酮的工艺研究

目的建立超声法提取山楂果实总黄酮的最佳提取工艺。方法以总黄酮收率为指标,正交设计法优化山楂总黄酮的提取工艺。结果最佳超声提取工艺:乙醇浓度为70%,料液比为1:20,超声提取时间为40min,提取率3.85%。结论该方法可用于山楂总黄酮的提取,提取方法简单易行、提取时间短、效率高。     

正交试验法优选银杏叶提取条件

目的采用正交试验法优选银杏叶破碎提取的最佳条件。方法考察溶剂用量、乙醇浓度和提取时间3个因素,每个因素选取3个水平进行实验。结果与结论最佳工艺为A3B3C3,即用10倍量70%乙醇破碎提取2次,时间为3min,优选得到的工艺稳定可行。     

正交试验法优选银杏叶提取条件※

目的采用正交试验法优选银杏叶破碎提取的最佳条件.方法考察溶剂用量、乙醇浓度和提取时间3个因素,每个因素选取3个水平进行实验.结果与结论最佳工艺为A3B3C3,即用10倍量70%乙醇破碎提取2次,时间为3min,优选得到的工艺稳定可行.     

护心颗粒提取工艺的研究

目的 研究护心颗粒制备的水提工艺条件.方法 以黄芪甲苷含量为考察指标,用正交实验法L9(34)正交表来安排试验,确定提取工艺.结果 各因素对提取工艺的影响大小为:煎煮次数>加水量>煎煮时间.结论 最佳提取方案为加6倍量,水煎煮2次,每次1.5小时.     

消化颗粒的制备工艺分析及应用

目的探讨消化颗粒的制备工艺。方法以选用颗粒载药量为指标,对消化颗粒的制备工艺进行优选。结果将药材提取2次,分别为30min及20min,加8倍量水;浓缩浸膏至45%水分,加15.0ml乙醇制粒为最佳工艺条件。结论本实验筛选出了消化颗粒的最佳制备工艺,符合《中国药典》要求。     

止咳祛痰灵颗粒剂的制备工艺研究

目的探讨止咳祛痰灵颗粒剂的制备工艺。方法以选用颗粒载药量为指标,对止咳祛痰灵颗粒剂的制备工艺进行优选。结果将药材提取2次,分别为30min及20min,加8倍量水;浓缩浸膏至45%水分,加15.0ml 95%乙醇制粒为最佳工艺条件。结论本实验筛选出了止咳祛痰灵的最佳制备工艺,符合《中国药典》要求。     

正交试验法优选黄芪西洋参口服液提取工艺的研究

目的 优选黄芪西洋参口服液的最佳提取工艺条件.方法 以总皂苷含量为指标,对影响提取的重要因素 A 加水量,B 提取次数,C 提取时间进行 L9(34)正交试验设计.结果 与结论最佳提取工艺为药材加 6 倍量水,提取 2 次,提取 1.5h/次,优选得到的工艺稳定可行.     

超声波作用从大豆皮中提取果胶多糖

在超声波作用下，从豆皮中提取果胶多糖，在提取过程中，通过正交实验，得到最佳工艺条件为：草酸铵浓度为0．8％，料液比为1：40，提取温度为45℃．提取时间为20min。     

阿莫西林克拉维酸钾薄膜衣片的制备工艺研究

目的本研究主要对阿莫西林克拉维酸钾的薄膜衣片进行了制备工艺的研究。方法通过对制剂处方的筛选和考察生产工艺的条件,确定最佳阿莫西林克拉维酸钾的薄膜衣片制备工艺。结果与结论本制剂工艺的实验可行,工艺稳定可靠,所制备的薄膜衣片符合相关要求。     

甘露退热颗粒制备工艺及质量标准

目的 探讨甘露退热颗粒的制备工艺、质量标准,以有效控制甘露退热颗粒的质量,使甘露退热颗粒达到新制剂报备水平。方法 以甘露退热颗粒的浸膏得率、钙离子提取量、后下药粉碎度等为考察指标,不同的煎煮时间、加水量、煎煮次数等条件,用正交法试验进行统计评价,分别研究先煎药、后下药、共煎药的最佳提取工艺;并用薄层色谱作为鉴别方法。结果 甘露退热颗粒的最佳提取工艺为先煎药加14倍水提取2次每次1 h后与共煎药定量至12倍水,提取2次,每次90 min。后下药粉碎后过10目筛加8倍水煮6 h提取挥发油。黄芩、土茯苓进行薄层色谱法鉴别是切实可行的。结论本文设计的甘露退热颗粒的制备工艺及质量标准准确可靠,可用于建立甘露退热颗粒的质量标准。     

紫外-可见分光光度法测定不同产地山楂果实中总黄酮含量

目的建立紫外-可见分光光度法测定不同产地山楂果实中总黄酮含量。方法采用超声法提取山楂果实中的总黄酮,采用紫外-可见分光光度法测定不同产地山楂总黄酮含量,检测波长为500nm。结果芦丁在质量浓度20-120μg/mL（r=0.9993）范围内与吸光度值线性关系良好,平均回收率为100.1%,RSD=0.3%（n=6）,来自8个产地的总黄酮含量在3.53%-4.12%之间。结论本方法简便、准确,重复性好,可快速测定山楂果实中总黄酮的含量;不同产地山楂总黄酮的含量存在一定差异,本实验可为控制山楂的质量提供参考依据。     

山菠萝药材中总黄酮的含量测定

目的建立紫外分光光度法测定山菠萝总黄酮的方法。方法采用紫外分光光度法,以芦丁为对照品,以亚硝酸钠-硝酸铝-氢氧化钠显色剂,在波长505nm处对山菠萝药材中总黄酮进行含量测定。结果总黄酮在0.025～0.124mg/ml范围内线性关系良好（r=0.9992）;该法的平均加样回收率为99.27%,RSD=0.83%（n=9）;山菠萝药材中总黄酮的平均含量为13.75mg/g,3批药材含量差异较大（RSD=8.77%,n=3）。结论紫外分光光度法简便快速,稳定可靠,适用于山菠萝中总黄酮的含量测定。     

THE ECONOMICS OF GASOHOL

Gasohol has received considerable governmental financial support because it is alleged to have important ecological and economic advantages. It is, for instance, supposed to reduce our extraction of nonrenewable energy, to have a cost advantage over gasoline, and to reduce pollution. This essay presents evidence that the amount of nonrenewable energy used in producing the corn ethanol is less than the amount of energy it provides as a fuel, that its price competitiveness with gasoline is doubtful, and that its environmental benefits are far from proven. In brief, current U.S. policies encouraging ethanol production to produce gasohol do not seem economically rational. ( JEL Q100, Q400, D210, L780)     

The optimum population and growth: a new look; a modification to include a preference for children in the welfare function

An econometric model is proposed whereby optimum population levels can be defined. An optimum population is less than the maximum and varies according to several factors. The static optimum population which determines optimum solely by per capita income is inadequate since any level of welfare can always be increased by merely reducing the population. Other conditions for figuring social welfare must be used. A dynamic optimum population must be figured on the basis of such factor s as a preference for leisure or for open spaces. The prediction of optimum population levels is useful for the formulation of social policy.     

Optimal population size and endogenous growth

"Many applications in economics require the selection of an objective function which enables the comparison of allocations involving different population sizes. The two most commonly used criteria are the Benthamite and the Millian welfare functions, also known as classical and average utilitarianism, respectively. The former maximizes total utility of the society and thus represents individuals, while the latter maximizes average utility and so represents generations. Edgeworth (1925) was the first to conjecture, that the Benthamite principle leads to a larger population size and a lower standard of living.... The purpose of this paper is to examine Edgeworth's conjecture in an endogenous growth framework in which there are interactions between output and population growth rates. It is shown that, under conditions that ensure an optimum, the Benthamite criterion leads to smaller population and higher output growth rates than the Millian."     

探讨银杏叶的生物学研究

目的探讨银杏叶的生物学特性,分析银杏叶的有效成分及药理作用。方法对大量成年银杏树和实生苗叶片形态及叶柄的解剖结构进行观察,对银杏叶提取物的成分进行分析测定,分析其主要活性成分,研究其药理作用及临床应用价值。结果与结论银杏叶主要为扇形,银杏叶中含有黄酮类、萜内酯类、聚异戊烯醇等多种成分,具有保护中枢神经系统功能、扩张血管、保护心脏、抗氧化等多种药理作用,具有较高的药用价值。     

Economic and demographic factors in U.S. alcohol demand: A growth-accounting analysis

During the 1980s, per capita consumption of absolute ethanol in the U.S. declined by 14 percent. In 1979, consumption was 2.94 gallons per capita compared to 2.52 gallons in 1989. The objective of this paper is to explain the decline in consumption, both for total ethanol and by beverage. The historical growth of ethanol demand is decomposed into several components, with emphasis on the role of relative prices, real income, and demographic factors. Using the Rotterdam model of a demand system, I first estimate the conditional demand for ethanol for each of the three beverages (beer, wine, distilled spirits). Second, I estimate the composite demand for total ethanol. Both sets of estimates are obtained using quarterly data for the period 1974–90. The estimates are tested for conformity with the theoretical restrictions of homogeneity, symmetry, and negativity. The decomposition analysis indicates a positive net effect for the combined impact of autonomous trend, real income growth, and relative price changes, both for total ethanol and each of the three beverages. The negative growth of per capita ethanol consumption is attributable to an increase in the proportion of the population aged 65 and over and a simultaneous decline in the proportion of the population aged 18–29.     

The projected costs and benefits of water diversion from and to the Sultan Marshes (Turkey)

The Sultan Marshes in the Develi Basin, Anatolia, one of twelve internationally important wetlands of Turkey, have been severely affected by the construction of an irrigation project in 1988. Intensive use of surface and ground water in irrigation has caused more than a 1 m decline in water levels and has affected the wetlands' ecological characteristics. Previous studies indicate that Sultan Marshes will need more water to restore viable ecological conditions. In this study, we analyze how economic benefits from agriculture and wetlands would be affected if moderate amounts of water were diverted from agriculture back to wetlands in the Develi Basin. By estimating total and marginal costs and benefits associated with water diversions, we determined the optimum or economically-efficient amount of water diversion. When only direct-use values of the wetland (animal grazing, plant harvesting, and ecotourism) were included in the analysis, the optimum amount of water diversion to the wetlands was found to be 5.2 million m³ year^− 1 (165 L sec^− 1), which compares to about 62 million m³ year^− 1 (1,957 L sec^− 1) used in irrigation. When wastewater treatment benefits (an indirect-use value) were added, the optimum amount rose to 7 million m³ year^− 1. Overall, the analysis showed that water diversion from agriculture to the Sultan Marshes is economically preferable.