[Objective] The aim was to improve part of auto-control system of aquatic seedling breeding and to lay foundation for highly-efficient and stable use of the sys- tem. [Method] The executive and drive modules of the au...[Objective] The aim was to improve part of auto-control system of aquatic seedling breeding and to lay foundation for highly-efficient and stable use of the sys- tem. [Method] The executive and drive modules of the auto-control system were im- proved, after which real-time monitor, data display and alarm modules were tested on time. [Result] In the test, for the improved system, stability and sensitivity were enhanced; different components matched better; transmitting electric resistanc6 was reduced. [Conclusion] The research provides references for auto-control of water temperature and dissolved oxygen, and faults clearing in aquatic seedling breeding.展开更多
Quorum sensing, or auto induction, as a cell density dependent signaling mechanism in many microorganisms, is trig- gered via auto inducers which passively diffuse across the bacterial envelope and therefore intracell...Quorum sensing, or auto induction, as a cell density dependent signaling mechanism in many microorganisms, is trig- gered via auto inducers which passively diffuse across the bacterial envelope and therefore intracellulaly accumulate only at higher bacterial densities to regulate specialized processes such as genetic competence, bioluminescence, virulence and sporulation. N-acyl homoserine lactones are the most common type of signal molecules. Aquaculture is one of the fastest-growing food-producing indus- tries, but disease outbreaks caused by pathogenic bacteria are a significant constraint on the development of the sector worldwide. Many of these pathogens have been found to be controlled by their quorum sensing systems. As there is relevance between the pathogenic bacteria＇s virulence factor expression and their auto inducers, quorum quenching is a new effective anti-infective strategy to control infections caused by bacterial pathogens in aquaculture. The techniques used to do this mainly include the following： （1） the inhibition of signal molecule biosynthesis, （2） blocking signal transduction, and （3） chemical inactivation and biodegradation of signal molecules. To provide a basis for finding alternative means of controlling aquatic diseases by quorum quenching instead of treatment by antibiotics and disinfectants, we will discuss the examination, purification and identification of auto inducers in this paper.展开更多
As is well known, deep mines are hot. As mining depth increases, the temperature of the surrounding rock also increases. This seriously affects mine safety and production and has restricted the exploitation of deep co...As is well known, deep mines are hot. As mining depth increases, the temperature of the surrounding rock also increases. This seriously affects mine safety and production and has restricted the exploitation of deep coal resources. Therefore, reducing the working face temperature to improve working conditions by controlling these heat hazards is an urgent problem. Considering problems in cooling deep mines both domestically and abroad along with the actual conditions of the Zhangshuanglou coal mine, we propose a HEMS technology that uses heat resources from deep mines in a stepwise manner. HEMS means a high temperature ex-change machinery system. Mine inrush-water is used as a source of cooling. Twice the energy is extracted from the mine inrush water. Heat is used for building heating in the winter and cold water is used for cooling buildings in the summer. This opens a new technology for stepwise utilization of heat energy in deep mines. Energy conservation and reduced pollution, an improved environment and sustainable economic development are realized by this technique. The economic and social effects are obvious and illustrate a good prospect for the application and extension of the method.展开更多
The paper presents data collected in an assessment of the effects of water hyacinth （Eichhornia crassipes） infestation on phytoplankton productivity in Lake Naivasha. A summary of the status of control and strategie...The paper presents data collected in an assessment of the effects of water hyacinth （Eichhornia crassipes） infestation on phytoplankton productivity in Lake Naivasha. A summary of the status of control and strategies used is given. The ecological effects of water hyacinth on the lake have received little attention compared to the large body of work available on the weed＇s socioeconomic impact. This study was conducted to determine the effect of hyacinth infestation on the phytoplankton productivity. Several sampling stations were set up in the lake at sites containing floating mats of the weed and at sites where the weed was absent. Phytoplankton chlorophyll-a concentration and dissolved oxygen were measured at each station and used as proxies for phytoplankton productivity. The findings show that phytoplankton productivity in weed covered areas is reduced with significant change in species composition and biodiversity suggesting that water hyacinth can alter the ecology of the lake. Although water hyacinth has continued posing serious ecological consequences, the control strategies already adopted will continue to reduce deleterious impacts and allow sustained development in the Lake Naivasha Basin. There is need however to undertake research to quantify the level of ecological damage and the costs of control. There are other effects such as livelihood loss, diseases, and disruption of normal operations that also need to be quantified.展开更多
文摘[Objective] The aim was to improve part of auto-control system of aquatic seedling breeding and to lay foundation for highly-efficient and stable use of the sys- tem. [Method] The executive and drive modules of the auto-control system were im- proved, after which real-time monitor, data display and alarm modules were tested on time. [Result] In the test, for the improved system, stability and sensitivity were enhanced; different components matched better; transmitting electric resistanc6 was reduced. [Conclusion] The research provides references for auto-control of water temperature and dissolved oxygen, and faults clearing in aquatic seedling breeding.
文摘Quorum sensing, or auto induction, as a cell density dependent signaling mechanism in many microorganisms, is trig- gered via auto inducers which passively diffuse across the bacterial envelope and therefore intracellulaly accumulate only at higher bacterial densities to regulate specialized processes such as genetic competence, bioluminescence, virulence and sporulation. N-acyl homoserine lactones are the most common type of signal molecules. Aquaculture is one of the fastest-growing food-producing indus- tries, but disease outbreaks caused by pathogenic bacteria are a significant constraint on the development of the sector worldwide. Many of these pathogens have been found to be controlled by their quorum sensing systems. As there is relevance between the pathogenic bacteria＇s virulence factor expression and their auto inducers, quorum quenching is a new effective anti-infective strategy to control infections caused by bacterial pathogens in aquaculture. The techniques used to do this mainly include the following： （1） the inhibition of signal molecule biosynthesis, （2） blocking signal transduction, and （3） chemical inactivation and biodegradation of signal molecules. To provide a basis for finding alternative means of controlling aquatic diseases by quorum quenching instead of treatment by antibiotics and disinfectants, we will discuss the examination, purification and identification of auto inducers in this paper.
基金Financial support for this project, provided by the National Basic Research Program of China (No. 2006CB202200)the National Major Project of Ministry of Education (No.304005) the Program for Changjiang Scholars and Innovative Research Team in University of China (No.IRT0656), is gratefully acknowledged
文摘As is well known, deep mines are hot. As mining depth increases, the temperature of the surrounding rock also increases. This seriously affects mine safety and production and has restricted the exploitation of deep coal resources. Therefore, reducing the working face temperature to improve working conditions by controlling these heat hazards is an urgent problem. Considering problems in cooling deep mines both domestically and abroad along with the actual conditions of the Zhangshuanglou coal mine, we propose a HEMS technology that uses heat resources from deep mines in a stepwise manner. HEMS means a high temperature ex-change machinery system. Mine inrush-water is used as a source of cooling. Twice the energy is extracted from the mine inrush water. Heat is used for building heating in the winter and cold water is used for cooling buildings in the summer. This opens a new technology for stepwise utilization of heat energy in deep mines. Energy conservation and reduced pollution, an improved environment and sustainable economic development are realized by this technique. The economic and social effects are obvious and illustrate a good prospect for the application and extension of the method.
文摘The paper presents data collected in an assessment of the effects of water hyacinth （Eichhornia crassipes） infestation on phytoplankton productivity in Lake Naivasha. A summary of the status of control and strategies used is given. The ecological effects of water hyacinth on the lake have received little attention compared to the large body of work available on the weed＇s socioeconomic impact. This study was conducted to determine the effect of hyacinth infestation on the phytoplankton productivity. Several sampling stations were set up in the lake at sites containing floating mats of the weed and at sites where the weed was absent. Phytoplankton chlorophyll-a concentration and dissolved oxygen were measured at each station and used as proxies for phytoplankton productivity. The findings show that phytoplankton productivity in weed covered areas is reduced with significant change in species composition and biodiversity suggesting that water hyacinth can alter the ecology of the lake. Although water hyacinth has continued posing serious ecological consequences, the control strategies already adopted will continue to reduce deleterious impacts and allow sustained development in the Lake Naivasha Basin. There is need however to undertake research to quantify the level of ecological damage and the costs of control. There are other effects such as livelihood loss, diseases, and disruption of normal operations that also need to be quantified.
