• 제목/요약/키워드: Primary production

검색결과 1,539건 처리시간 0.054초

Lead increases Nitric Oxide Production in Immunostimulated Glial Cells

  • Choi, Min-Sik;Shin, Chan-Young;Ryu, Jae-Ryun;Lee, Woo-Jong;Cheong, Jae-Hoon;Choi, Chang-Rak;Kim, Won-Ki;Ko, Kwang-Ho
    • Biomolecules & Therapeutics
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    • 제12권4호
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    • pp.209-214
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    • 2004
  • Lead has long been considered as a toxic environmental pollutant that severely damages the central nervous system. In various neurogenerative diseases, actrocytes become activated by proinflammatory cytokines. In the present study, we investigated whether lead (Pb$^{2+}$) affects inducible nitric oxide synthase (iNOS) expression in activated glial cells. Rat primary glial cells were stimulated with lipopolysaccharide (LPS, 1 ${\mu}$g/ml) plus IFN$_{\gamma}$(100 U/ml). Pre-treatment of Pb$^{2+}$ increased nitric oxide (NO) production in LPS/IFN$_{\gamma}$-stimulated glial cells. Lead itself, however, suppressed the basal production of NO in control glial cells. Addition of the iNOS inhibitors L-NAME (1 mM) and L-NNA (800 ${\mu}$M) prevented the Pb$^{2+}$-induced increase in NO production. Western blot analysis showed that pre-treatment of Pb$^{2+}$ augmented LPS/IFN$_{\gamma}$-induced increase in iNOS immunoreactivity, which was well correlated with the increased NO production. In addition, pre-treatment of Pb$^{2+}$ synergistically increased the iNOS mRNA expression induced by LPS and IFN${\gamma}$. The present results indicate that lead intoxication adversely affect brain function by potentiating iNOS expression and NO production in activated glial cells observed in various neurodegenerative diseases.

AN ASSESSMENT OF FACTORS ASSOCIATED WITH INCREASED PRODUCTIVITY OF DAIRY FARMS IN FIJI

  • Kerr, D.V.;Fell, R.F.;Murray, A.J.;Chaseling, J.
    • Asian-Australasian Journal of Animal Sciences
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    • 제8권5호
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    • pp.481-487
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    • 1995
  • A survey of physical inputs was conducted on the total population of dairy farms supplying milk to the Rewa cooperative dairy company in Fiji. The critical inputs associated with total farm milk production were determined using multiple regression, with analyses being conducted for each of the three identified supplier groups, bulk milk, canned milk and cream. Mean annual milk production per cow averaged 1460 (s.d. = 319), 889 (s.d. = 321) and 800 (s.d. = 451) litres for the bulk milk, canned milk and cream suppliers respectively. Stocking rate averaged 1.37 (s.d. = 1.18) cows per hectare over all farms. Inputs to pasture were universally low and Navua sedge (Cyperus aromaticus) was identified as a major weed. The average amount of supplement fed annually on a grain equivalent basis was 700 (s.d. = 984) kg per cow for bulk milk, 84 (s.d. = 198) kg per cow for canned milk and 146 (s.d. = 542) kg per cow for cream suppliers. The analysis of data from a small group of farms using nitrogen fertiliser indicated that their production levels were higher than the general population. This suggests that there is potential for the Fijian dairy industry to increase milk production through the use of higher inputs to cows and pastures. The regression models relating annual milk production from farms to the two key inputs of number of cows milked and the amount of supplement fed were all significant (p < 0.001). The coefficients of determination for these models ranged from 56.9 to 89.4 percent.

A Study on Production of Nitrogen Oxides in Plasma Reactors

  • Lim, Gye-Gyu
    • Journal of Korean Society for Atmospheric Environment
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    • 제17권E3호
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    • pp.91-99
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    • 2001
  • Plasma reactor was used to generate a high potential difference between two surfaces of concentric pyrex tubes by electrical current. The annular gap of the reactor was calculated by trial and error from the breakdown voltage equation and set at 0.45 cm. The overall objective of this research was to know the effects of the frequency, humidity, and residence time on the formation of nitrogen oxides in a plasma reactor. The primary voltage varied from 50 to 90 volts and the frequency was varied in increments of 10 Hz from 60 to 650 Hz at the primary voltage of 90. The increase in the secondary voltage was not linear but exponential at high frequencies. At a maximum concentration of about 745 ppm, the frequency and secondary voltage was 600 Hz and 4,200 volts, respectively. All tests for the effects of humidity on NO$_{x}$ production were performed at the optimal setting of 90 colts and 600 Hz frequency. Since the NO$_{x}$ production was not an one dimensional phenomenon, competing reactions were assumed to occur in the discharge chamber. The sharp peak concentration of 1,810 ppm was observed at 38% of relative humidity, The enhanced production was choked off, and the production rate rapidly dropped to 3 ppm at above 40% of relative humidity. It is assumed that the corona attacks the most vulnerable molecules in the reaction chamber before attacking other more lightly bonded molecules, possibly at humidities above 38% and the optimized 90 volt setting. Thus, there was not enough energy left after attacking all water molecules to decompose an appreciable amount of $N_2$. If nitrogen breakdown does not occur, then oxides of nitrogen are not likely to be produced.ced.

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물 자원 생산을 위한 Coal Seam Gas Water Management Study의 평가 및 분석 -1. 용수 생산 (Assessment and Analysis of Coal Seam Gas Water Management Study for Water Resource Production -1. Water Production)

  • 신춘환
    • 한국환경과학회지
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    • 제23권8호
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    • pp.1395-1407
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    • 2014
  • Coal seam gas (CSG) production involves extracting methane from coal seams with ground water which is so called a primary by-product of this process, and is often rich in salts and other constituents. The predicted large volume and variable quality of this water make water management a topic associated with CSG production. In the past, the amount of this water used to be pumped into the vacant aquifer, or into the river during the life of individual production wells. Australian government make a strategies for management and beneficial use of the water. From this point of view, a detailed assessment has not been undertaken, it is necessary for water resource production to analysis the "Coal Seam Gas Water (CSG Water) Management Policy Study" published in Queensland, Australia.

태양광 발전 소재 생산계획을 위한 선형계획 모형 (A Linear Programming Model for Production Planning of Photovoltaic Materials)

  • 이선종;이현철;김재희
    • 경영과학
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    • 제32권4호
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    • pp.19-28
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    • 2015
  • This study presents a mathematical programming model to develop production planning in the manufacturing processes for photovoltaic silicon ingots and wafers. The model is formulated as a linear programming model that maximizes total growth margin, which is composed of production cost, inventory cost, shortage cost, and sales profit while considering the constraints associated with the production environments of photovoltaic materials. In order to demonstrate the utility of the model for production planning, we run operations for a planning horizon of a year for a case study. When the primary results of this mathematical programming are compared with the historical records, the model could have resulted in the considerable increase of the total growth margin by effectively reducing inventory cost if a decision maker had employed the model as a decision support system with perfect information for sales demand.

COMPUTER PROGRAMS WHICH ENABLE PRICING OF SHEEP AND LAMB CARCASSES BASED ON YIELD ESTIMATION SUITABILITY AND FINANCIAL PARAMETERS

  • Hopkins, D.L.;Hayhurst, G.;Horcicka, J.V.
    • Asian-Australasian Journal of Animal Sciences
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    • 제5권1호
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    • pp.1-5
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    • 1992
  • A computer program called LAMPRO has been developed for use by the Australian meat industry to assist with the pricing of lamb carcasses. Based on a series of prediction equations and accounting for the cost structure of a meat processor the program allows the real value of a carcass to be established. The concept has also been extended to cater for mutton carcasses destined for either domestic or export markets incorporated in a program called MUTONPRO.

Biomass and secondary production of the three dominant amphipods (Crustacea) in a temperate sandy shore, southern Korea

  • Hwan, Yu-Ok;Rip, Seo-Hae
    • 한국어업기술학회:학술대회논문집
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    • 한국어업기술학회 2001년도 춘계 수산관련학회 공동학술대회발표요지집
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    • pp.435-436
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    • 2001
  • In sand beaches the benthic macrofauna feeding on primary food sources such as detritus and phytoplankton and being prey in turn for top predators such as fishes occupies a key position in the center of food chains. Amphipods are the most productive bentho-pelagic animals (Barnard, 1963) and are commonly consumed by fishes and larger crustaceans (Vetter, 1995). Consequently, amphipods play an important role in energy flow as a trophic link from primary producers to higher consumers(Chiaravalle et al., 1997).

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Primary Production System in the Southern Waters of the East Sea, Korea III. Vertical Distribution of the Phytoplankton in Relation to Chlorophyll Maximum Layer

  • Shim, Jae-Hyung;Park, Jong-Gyu
    • Journal of the korean society of oceanography
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    • 제31권4호
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    • pp.196-206
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    • 1996
  • Vertical profiles of the chlorophyll ${\alpha}$, phytoplankton abundance, nutrients and sigma-t were compared with the vertical distribution of phytoplankton species in conjunction with $^{14}$C primary production in the Southern Waters of the East Sea, Korea. In the upper mixed layer the water column was only weakly stratified and ambient nitrogenic nutrient concentrations were markedly depleted. Dissolved silicate seemed to be another limiting nutrient in the surface layer. The occupation of different water depths by several dominant diatom species was well explained by the degree of silicification of each cell and the silicate concentration of ambient seawater. Subsurface chlorophyll maxima were continuously observed in the lower parts of the euphotic layer and the depth coincided with nutricline, supporting our view that chlorophyll maximum was sustained partially by enhancement of in situ growth of phytoplankton and partially by increase of cellular chlorophyll content. The persistence of chlorophyll maximum layer was attributed to the physiological adaptation of the phytoplankters to low light intensities and to the utilization of regenerated nutrients. Integrated water column production of organic matter by photosynthesis appeared to be better related to phytoplankton cell division than to the cell growth in terms of biosynthesis of pigments and other intracellular components.

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