Lepidium meyeniiWalp. （Maca）, a perennial herbaceous plant with narrow distdbution in the Andean region, was cultivated by local residents as early as 1600 B.C. It has high nutritional values and multiple medicinal ...Lepidium meyeniiWalp. （Maca）, a perennial herbaceous plant with narrow distdbution in the Andean region, was cultivated by local residents as early as 1600 B.C. It has high nutritional values and multiple medicinal effects. In recent years the plant source of Maca has been greatly scarce since Maca products are increasingly becoming popular in the world. This makes the study urgent on the identification and quality evaluation of Maca materials. In present work, four Mace samples of different origins or handlings and three other natural plants, including radish, odental ginseng and American ginseng, were investigated. Their essential oils （steam distillates） of the hypogeal parts were weighed and analyzed by GC/MS. Through comparison of the characteristics of their chromatograms, it was found that the essential oil of Maca had unique GC/MS behaviors, and the characteristic peaks produced by the major essential oil components （Phenylacetonitrile, Benzaldehyde, 3-Methoxyphenylacetonitrile, etc） were distinct. Furthermore, the chromatograms of several Maca samples showed a similar qualitative pattern except for some differences in the quantitative composition, and the percentage of total essential oils in the samples varied from 0.88 % to 1.59 %. These behaviors and technologies can be applied to the identification of Maca materials in the markets and be a supplement to assess the quality of Maca matedals.展开更多
The volatile oil of leaves and barks of Calycopteris floribunda was examined by gas chromatography-mass spectrometry (GC-MS). 52 volatile chemical components in leaves were identified. The antimicrobial assay of oils ...The volatile oil of leaves and barks of Calycopteris floribunda was examined by gas chromatography-mass spectrometry (GC-MS). 52 volatile chemical components in leaves were identified. The antimicrobial assay of oils in the leaves and barks was carried out by disk diffusion method in vitro. The major components (mass fraction) in leaves are caryophyllene oxide (13.79%),n-hexadecanoic acid (11.91%) and β-caryophyllene (10.45%). Ten constituents are identified accounting for about 99.98% of the total volatile oil in the bark. Among these components,n-hexadecanoic acid (59.18%),linolic acid (12.70%) and butyl octyl phthalate (8.21%) are the major constituents. The oils exhibit strong antimicrobial activity and display more potent against bacteria than fungi.展开更多
Exposure to CO （carbon monoxide） during cooking in households using LPG （liquefied petroleum gas）, natural gas and charcoal as fuels has been conducted. The study aimed at assessing the indoor air quality in order...Exposure to CO （carbon monoxide） during cooking in households using LPG （liquefied petroleum gas）, natural gas and charcoal as fuels has been conducted. The study aimed at assessing the indoor air quality in order to address potential hazards associated with CO. Carbon monoxide concentrations and flame temperature were measured at an interval of 1 min for 1 h using CO and thermometer data loggers respectively. While the CO concentration from LPG and natural gas were found below 26 ppm for 1 h, as recommended by WHO （World Health Organization） standards, the average CO concentration from charcoal exceeded the standard limit. In addition closing the kitchen door during cooking increased the CO concentration from 26-295 ppm to 92-597 ppm. According to WHO, the observed CO concentrations from charcoal stove highlights questionable life support atmosphere. It can therefore be suggested that switching to LPG or natural gas from charcoal will reduce CO exposure to persons during cooking.展开更多
The reforms in oil and gas sector have been accelerated in 2015. The reform of mineral rights has begun and 6 oil and gas exploration zones in Xinjiang Autonomous Region have served as the tender pilots, breaking thro...The reforms in oil and gas sector have been accelerated in 2015. The reform of mineral rights has begun and 6 oil and gas exploration zones in Xinjiang Autonomous Region have served as the tender pilots, breaking through the requirements on the resources varieties, exploration phase and enterprise qual!fication. The right of importing and using of the crude oil has been gradually relaxed and 13 local refineries have obtained the right to use imported crude oil of 55.1888 million tons per year. The natural gas price for non-residential use was unified and a universal price was set ~r the incremental supply and existing supply. Tire Shanghai Petroleum and Gas Exchange （SHPGX） was established and laid foundation for the market mechanism to detervnine the price. The government governance has undergone continuous adjustments such as regulating the tax instead of charging the fees, streamlining administration and delegating power to tire lower levels.The Guidelines on Deepening tire Reform of State-owned Enterprises was released, symbolizing the accomplishment of the overall planning ~ the SOE reform.展开更多
文摘Lepidium meyeniiWalp. （Maca）, a perennial herbaceous plant with narrow distdbution in the Andean region, was cultivated by local residents as early as 1600 B.C. It has high nutritional values and multiple medicinal effects. In recent years the plant source of Maca has been greatly scarce since Maca products are increasingly becoming popular in the world. This makes the study urgent on the identification and quality evaluation of Maca materials. In present work, four Mace samples of different origins or handlings and three other natural plants, including radish, odental ginseng and American ginseng, were investigated. Their essential oils （steam distillates） of the hypogeal parts were weighed and analyzed by GC/MS. Through comparison of the characteristics of their chromatograms, it was found that the essential oil of Maca had unique GC/MS behaviors, and the characteristic peaks produced by the major essential oil components （Phenylacetonitrile, Benzaldehyde, 3-Methoxyphenylacetonitrile, etc） were distinct. Furthermore, the chromatograms of several Maca samples showed a similar qualitative pattern except for some differences in the quantitative composition, and the percentage of total essential oils in the samples varied from 0.88 % to 1.59 %. These behaviors and technologies can be applied to the identification of Maca materials in the markets and be a supplement to assess the quality of Maca matedals.
基金Project(2007-1718) supported by Development and Reform Commission of Yunnan Province, China
文摘The volatile oil of leaves and barks of Calycopteris floribunda was examined by gas chromatography-mass spectrometry (GC-MS). 52 volatile chemical components in leaves were identified. The antimicrobial assay of oils in the leaves and barks was carried out by disk diffusion method in vitro. The major components (mass fraction) in leaves are caryophyllene oxide (13.79%),n-hexadecanoic acid (11.91%) and β-caryophyllene (10.45%). Ten constituents are identified accounting for about 99.98% of the total volatile oil in the bark. Among these components,n-hexadecanoic acid (59.18%),linolic acid (12.70%) and butyl octyl phthalate (8.21%) are the major constituents. The oils exhibit strong antimicrobial activity and display more potent against bacteria than fungi.
文摘Exposure to CO （carbon monoxide） during cooking in households using LPG （liquefied petroleum gas）, natural gas and charcoal as fuels has been conducted. The study aimed at assessing the indoor air quality in order to address potential hazards associated with CO. Carbon monoxide concentrations and flame temperature were measured at an interval of 1 min for 1 h using CO and thermometer data loggers respectively. While the CO concentration from LPG and natural gas were found below 26 ppm for 1 h, as recommended by WHO （World Health Organization） standards, the average CO concentration from charcoal exceeded the standard limit. In addition closing the kitchen door during cooking increased the CO concentration from 26-295 ppm to 92-597 ppm. According to WHO, the observed CO concentrations from charcoal stove highlights questionable life support atmosphere. It can therefore be suggested that switching to LPG or natural gas from charcoal will reduce CO exposure to persons during cooking.
文摘The reforms in oil and gas sector have been accelerated in 2015. The reform of mineral rights has begun and 6 oil and gas exploration zones in Xinjiang Autonomous Region have served as the tender pilots, breaking through the requirements on the resources varieties, exploration phase and enterprise qual!fication. The right of importing and using of the crude oil has been gradually relaxed and 13 local refineries have obtained the right to use imported crude oil of 55.1888 million tons per year. The natural gas price for non-residential use was unified and a universal price was set ~r the incremental supply and existing supply. Tire Shanghai Petroleum and Gas Exchange （SHPGX） was established and laid foundation for the market mechanism to detervnine the price. The government governance has undergone continuous adjustments such as regulating the tax instead of charging the fees, streamlining administration and delegating power to tire lower levels.The Guidelines on Deepening tire Reform of State-owned Enterprises was released, symbolizing the accomplishment of the overall planning ~ the SOE reform.
