In this study,we have examined the effects of exposure to high temperature, carbon inonoxideor a combination of both conditions in a model system,the rat and in industrial workers.In the rat liver, HSP70 mRNA and HSP7...In this study,we have examined the effects of exposure to high temperature, carbon inonoxideor a combination of both conditions in a model system,the rat and in industrial workers.In the rat liver, HSP70 mRNA and HSP70 synthesis were measured by dot hybridization and western blot. The results showed that after a heat stress HSP70 mRNA and its product, HSP70 increased significantly and there was a synergism in the combined effects of high temperature and carbon monoxide exposure on the induction of HSP70 mRNA and HSP70 synthesis. Heat played a major role in this induction. The presence of antibodies to human HSP27, HSP60, HSP70,HSC73, HSP89 αand β in workers exposed to heat, carbon monoxide was also measured by western blot using purified HSPs as antigens. Plasma free amino acids were measured in the saine group of workers. The incidence of antibodies to HSP27 and HSP70 Was significantly higher in the workers working in an environment with extreme heat, and high carbon monoxide ernission than in a control group. The carbon monoxide exposed group showed the highest incidence of antibodies to HSPs. Although our previous results indicated that workers had an insufficient protein intake,plasma free amino acids tended to increase, especially in methionine and tryptophan two kinds of amino acids which are absent from the main stress protein, HSP70.These results suggest that the major problems that these workers may face are how to facilitate the use of plasma free amino acids and reduce the inhibition of synthesis of normal proteins when they are exposed to occupational harmful factors.These resultsalso add new information on the measurement of HSPs as a potential biomonitor to assess whether organisms are experiencing metabolic stress within their environment.展开更多
Greenhouse tomato plants (Lycopersicon esculentum Mill cv. Capello) were grown on peat-based substrate and treated with high (4.5 mS cm-1) and low (2.3 mS cm-1) nutrient solution electric conductivity(EC) under high a...Greenhouse tomato plants (Lycopersicon esculentum Mill cv. Capello) were grown on peat-based substrate and treated with high (4.5 mS cm-1) and low (2.3 mS cm-1) nutrient solution electric conductivity(EC) under high and low substrate water contents. FOur weeks after the beginning of the treatments, photosynthesis (Th) was measured under different humidity and temperatures to examine the interactive effectswith rhizosphere salinity and water deficit. A rectangular hyperbolic model fitted the light-photosynthesiscurve. Photosynthetic capacity (PC) was decreased but quantum yield (YQ) was increased by rhizospheresalinity caused by high EC. PN was decreased by low humidity only in high EC- and/or water-stressed plants.Under high photosynthetic photon flux (PPF), low humidity induced PC decline in water-stressed plants andPN oscillation in high-EC-treated plants. PN increased steadily as the leaf temperature changed from 18 Cto 23 and then decreased steadily from 23 to 38 . At 34 , PN decreased significantly in waterstressed plants. Dark respiration (RD) increased in an exponential manner as the leaf temperature changedfrom 18 to 38 to an extent about ten times higher under 38 than under 18 . Our data suggestedthat PN decrease under high temperature was attributed, st least in part, to the increased RD. RD in highEC- and/or water-stressed plants was higher than that in the plants of control under lower temperature butlower than that in the plants of control under high temperature. The analysis of stomatal and mesophyllconductance showed that low humidity effect was mainly through stomatal response while temperature effectwas mainly through biochemical functions. The result showed that environmental stresses affected PN in anadditive or synergistic manner.展开更多
The influence of daytime tropical heat stress in the summer was studied in Holstein and Jersey heifers already acclimatized to tropical environments to determine their physiological response based on body thermal patt...The influence of daytime tropical heat stress in the summer was studied in Holstein and Jersey heifers already acclimatized to tropical environments to determine their physiological response based on body thermal patterns and respiratory alterations according to psychrometric caloric indicators. Daytime psychrometric elements showed a tropical caloric potential for developing moderate to severe heat stress in dairy cattle. Body temperature and respiratory rate increased in both breeds open and pregnant (P < 0.01). Thermal body overload and respiratory works increased from 09 am to 12 md (P < 0.001);reaching and sustaining hyperthermia under the highest caloric pressure from 12 md to 03 pm. Rectal temperature increased +1.5˚C in open Holstein (OH), +1.3˚C in pregnant Holstein (PH), +0.8˚C in open jersey (OJ) and +0.8˚C in pregnant Jersey (PJ). The lowest heat stress index (HSI) was at 06 am, where OH and PH showed a HIS +2.25 and +2.30 and OJ and PJ +2.34 and +2.38. Maximum heat stress occurred at 12 md where OH averaged +3.28 and Pregnant Holsteins showed +3.85 at 03 pm. Open Jersey (OJ) showed a maximum HSI at 12 md (3.54) and PJ resulted in +3.89 at 03 pm. Open and pregnant Jersey heifers were more tolerant to heat stress based on lower body mass, insulation, feed consumption and greater relation between body surface and metabolic body size for thermolysis. Acclimatization between five and twenty-five months under tropical heat stress allowed Holstein and Jersey heifers to develop thermal tolerance. Middle thermal acclimatization lowered thermal sensitivity, hyperthermia and hyperpnea in Holstein and Jersey heifers in the morning;however, pregnant heifers in both breeds showed higher thermal alteration in the afternoon. Tropical acclimatization at low altitudes could be integrated with environmental improvements and nutritional and health management to reduce influences of severe heat stress and improve physiological comfort and welfare in Holstein and Jersey heifers in the summer. Those combined strategies will reduce daytime thermal and respiratory responses and allow growth, pregnancy and health with lower body heat overload and less hyperthermia.展开更多
Upper limit of thermal stability and subsequent rise of thermoregulatory functions are affected by body temperature. This study was designed to determine the effects of rectal temperature (RT) on dairy cows’ performa...Upper limit of thermal stability and subsequent rise of thermoregulatory functions are affected by body temperature. This study was designed to determine the effects of rectal temperature (RT) on dairy cows’ performance (heart rates (HR), respiratory rates (RR), milk yield (MY), dry matter intake (DMI), digestibility, plasma concentration of vitamin C under hot climate. This study was carried out in 2009, in north-west of Tunisia using 30 Holstein cows in mid lactation. The experiment was performed in spring (15th of February-15th of March: P1) and summer (1st-30th of August: P2). On each test day, temperature-humidity index (THI), RT, HR, RR, MY, DMI, digestibility and plasma VC concentration were determined. All this parameters were affected (P < 0.001) when the THI increased from 65.62 (P1) to 83.27 (P2). Regression analyses were carried out between THI index and some parameters (HR, RR, MY, DMI, digestibility, plasma concentration of vitamin C) and between RT and same parameters (HR, RR, MY, DMI, digestibility, plasma concentration of vitamin C). Characteristics of regression analyses in the two modes were different as also were R<sup>2</sup> and r (correlation coefficient) of the regressions. R<sup>2</sup> in regressions on RT (R<sup>2</sup> (RT, DMI) = 0.92 (P < 0.01);R<sup>2</sup> (RT, MY) = 0.91 (P < 0.001)) was markedly higher relative to R<sup>2</sup> in regressions on THI (R<sup>2</sup> (THI, DMI) = 0.76 (P < 0.001);R<sup>2 </sup>(THI, MY) = 0.63 (P < 0.001)). The two regressions modes suggest that increasing R<sup>2</sup> in regressions on RT confirms that rectal temperature constitutes a larger component of total variance of responses in dairy cows to hot environmental temperature.展开更多
This paper investigates the effects of site based parameters such as ambient temperature, humidity, altitude and heat transfer characteristic of a dual pressure heat recovery system on the performance of the combined ...This paper investigates the effects of site based parameters such as ambient temperature, humidity, altitude and heat transfer characteristic of a dual pressure heat recovery system on the performance of the combined cycle power plant within an equatorial environment. The bulk heat utilization and configuration of a dual pressure heat recovery system are investigated. It is observed that the heat system configuration play a vital role in optimizing the combined cycle overall performance, which has proportionality relationship with the operating ambient temperature and relative humidity of the gas turbine. The investigation is carried out within the ambient temperature range of 24℃ to 35℃, relative humidity of 60% to 80%, and a high level steam pressure of 60 bar to 110 bar. The results show that at 24℃ ambient temperature, the heat recovery system has the highest duty of 239.4 MW, the optimum combined cycle power output of 205.52 MW, and overall efficiency of 47.46%. It further indicates that as the ambient temperature increases at an average exhaust gas temperature of 530℃ and mass flow of 470 kg/s, the combined cycle power output and efficiency decrease by 15.5% and 13.7% respectively under the various considerations. This results from a drop in the air and exhaust mass flow as the values of the site parameters increase. The overall results indicate that decreasing the ambient temperature at optimum exhaust gas flow and temperature increases the heat recovery system heat duty performance, the steam generation, overall combined cycle power output and efficiency, which satisfies the research objective.展开更多
This study compared the effects of conventional thawing methods(water immersion thawing(WIT,(25±1)℃),natural air thawing(AT,(25±1)℃,relative humidity(RH(65±2)per cent),refrigerator thawing(RT,4℃,RH(8...This study compared the effects of conventional thawing methods(water immersion thawing(WIT,(25±1)℃),natural air thawing(AT,(25±1)℃,relative humidity(RH(65±2)per cent),refrigerator thawing(RT,4℃,RH(80±2)per cent)and low-temperature(LT)combined with high-humidity thawing LT,-1℃to 1℃(LT-1-1),2-4℃(LT2-4),5-7℃(LT5-7)and 8-10℃(LT8-10),RH>95 per cent)on the water-holding capacity,lipid oxidation and biochemical properties of Portunus trituberculatus(P.trituberculatus)myofibrillar protein.The results showed that WIT and AT significantly decreased the water-holding capacity while dramatically increasing lipid oxidation,protein oxidation and degeneration,resulting in serious P.trituberculatus quality deterioration.High humidity was beneficial for P.trituberculatus\.ha\A/\ng.The thawing time of P.trituberculatus under the conditions of LT2-4 was only 39.39 per cent of that of conventional air thawing at 4℃(RT),and the LT2-4 samples not only maintained better water-holding capacity but also had an obviously reduced degree of lipid oxidation,protein oxidation and denaturation.Thawed samples LT2-4 and LT5-7 provided better maintenance of P.trituberculatus quality than the LT-1-1 and LT8-10 samples.The best quality was exhibited after thawing at 2-4℃.The levels of thiobarbituric acid reacting substances,carbonyl content and surface hydrophobicity observably decreased in these samples,while the total sulfhydryl contents dramatically increased compared to those of conventionally thawed samples,indicating lower lipid oxidation and protein oxidation.Moreover,the Ca2+-ATPase activity of the sample thawed at 2-4℃(2.06 μmol Pi/mg prot/h)was markedly higher than that of samples subjected to WIT and AT.The product qualities observed after thawing at-1℃to 1℃,5-7℃and 8-10℃under LT were comparable to that observed by RT.Considering its thawing efficiency and product quality,LT is a suitable method for the thawing of P.trituberculatus,and the ideal thawing conditions were LT at 2-4℃.展开更多
A simple structure optical fiber sensor for relative humidity(RH) and temperature measurement is proposed and verified in this paper, which is based on graphene oxide quantum dots and polyvinyl alcohol(GOQDs-PVA) comp...A simple structure optical fiber sensor for relative humidity(RH) and temperature measurement is proposed and verified in this paper, which is based on graphene oxide quantum dots and polyvinyl alcohol(GOQDs-PVA) composite coated tapered no-core fiber(NCF) combined with a fiber Bragg grating(FBG). FBG is insensitive to humidity and sensitive to temperature, which is used to compensate temperature of the sensor. Experimental results show this sensor has humidity sensitivity of 143.27 pm/%RH ranging from 30%RH to 80%RH and the temperature sensitivity of 9.21 pm/℃. The proposed sensor has advantages of simple structure, good repeatability, and good stability, which is expected to be used in both RH and temperature measurement in biological and chemical fields.展开更多
文摘In this study,we have examined the effects of exposure to high temperature, carbon inonoxideor a combination of both conditions in a model system,the rat and in industrial workers.In the rat liver, HSP70 mRNA and HSP70 synthesis were measured by dot hybridization and western blot. The results showed that after a heat stress HSP70 mRNA and its product, HSP70 increased significantly and there was a synergism in the combined effects of high temperature and carbon monoxide exposure on the induction of HSP70 mRNA and HSP70 synthesis. Heat played a major role in this induction. The presence of antibodies to human HSP27, HSP60, HSP70,HSC73, HSP89 αand β in workers exposed to heat, carbon monoxide was also measured by western blot using purified HSPs as antigens. Plasma free amino acids were measured in the saine group of workers. The incidence of antibodies to HSP27 and HSP70 Was significantly higher in the workers working in an environment with extreme heat, and high carbon monoxide ernission than in a control group. The carbon monoxide exposed group showed the highest incidence of antibodies to HSPs. Although our previous results indicated that workers had an insufficient protein intake,plasma free amino acids tended to increase, especially in methionine and tryptophan two kinds of amino acids which are absent from the main stress protein, HSP70.These results suggest that the major problems that these workers may face are how to facilitate the use of plasma free amino acids and reduce the inhibition of synthesis of normal proteins when they are exposed to occupational harmful factors.These resultsalso add new information on the measurement of HSPs as a potential biomonitor to assess whether organisms are experiencing metabolic stress within their environment.
文摘Greenhouse tomato plants (Lycopersicon esculentum Mill cv. Capello) were grown on peat-based substrate and treated with high (4.5 mS cm-1) and low (2.3 mS cm-1) nutrient solution electric conductivity(EC) under high and low substrate water contents. FOur weeks after the beginning of the treatments, photosynthesis (Th) was measured under different humidity and temperatures to examine the interactive effectswith rhizosphere salinity and water deficit. A rectangular hyperbolic model fitted the light-photosynthesiscurve. Photosynthetic capacity (PC) was decreased but quantum yield (YQ) was increased by rhizospheresalinity caused by high EC. PN was decreased by low humidity only in high EC- and/or water-stressed plants.Under high photosynthetic photon flux (PPF), low humidity induced PC decline in water-stressed plants andPN oscillation in high-EC-treated plants. PN increased steadily as the leaf temperature changed from 18 Cto 23 and then decreased steadily from 23 to 38 . At 34 , PN decreased significantly in waterstressed plants. Dark respiration (RD) increased in an exponential manner as the leaf temperature changedfrom 18 to 38 to an extent about ten times higher under 38 than under 18 . Our data suggestedthat PN decrease under high temperature was attributed, st least in part, to the increased RD. RD in highEC- and/or water-stressed plants was higher than that in the plants of control under lower temperature butlower than that in the plants of control under high temperature. The analysis of stomatal and mesophyllconductance showed that low humidity effect was mainly through stomatal response while temperature effectwas mainly through biochemical functions. The result showed that environmental stresses affected PN in anadditive or synergistic manner.
文摘The influence of daytime tropical heat stress in the summer was studied in Holstein and Jersey heifers already acclimatized to tropical environments to determine their physiological response based on body thermal patterns and respiratory alterations according to psychrometric caloric indicators. Daytime psychrometric elements showed a tropical caloric potential for developing moderate to severe heat stress in dairy cattle. Body temperature and respiratory rate increased in both breeds open and pregnant (P < 0.01). Thermal body overload and respiratory works increased from 09 am to 12 md (P < 0.001);reaching and sustaining hyperthermia under the highest caloric pressure from 12 md to 03 pm. Rectal temperature increased +1.5˚C in open Holstein (OH), +1.3˚C in pregnant Holstein (PH), +0.8˚C in open jersey (OJ) and +0.8˚C in pregnant Jersey (PJ). The lowest heat stress index (HSI) was at 06 am, where OH and PH showed a HIS +2.25 and +2.30 and OJ and PJ +2.34 and +2.38. Maximum heat stress occurred at 12 md where OH averaged +3.28 and Pregnant Holsteins showed +3.85 at 03 pm. Open Jersey (OJ) showed a maximum HSI at 12 md (3.54) and PJ resulted in +3.89 at 03 pm. Open and pregnant Jersey heifers were more tolerant to heat stress based on lower body mass, insulation, feed consumption and greater relation between body surface and metabolic body size for thermolysis. Acclimatization between five and twenty-five months under tropical heat stress allowed Holstein and Jersey heifers to develop thermal tolerance. Middle thermal acclimatization lowered thermal sensitivity, hyperthermia and hyperpnea in Holstein and Jersey heifers in the morning;however, pregnant heifers in both breeds showed higher thermal alteration in the afternoon. Tropical acclimatization at low altitudes could be integrated with environmental improvements and nutritional and health management to reduce influences of severe heat stress and improve physiological comfort and welfare in Holstein and Jersey heifers in the summer. Those combined strategies will reduce daytime thermal and respiratory responses and allow growth, pregnancy and health with lower body heat overload and less hyperthermia.
文摘Upper limit of thermal stability and subsequent rise of thermoregulatory functions are affected by body temperature. This study was designed to determine the effects of rectal temperature (RT) on dairy cows’ performance (heart rates (HR), respiratory rates (RR), milk yield (MY), dry matter intake (DMI), digestibility, plasma concentration of vitamin C under hot climate. This study was carried out in 2009, in north-west of Tunisia using 30 Holstein cows in mid lactation. The experiment was performed in spring (15th of February-15th of March: P1) and summer (1st-30th of August: P2). On each test day, temperature-humidity index (THI), RT, HR, RR, MY, DMI, digestibility and plasma VC concentration were determined. All this parameters were affected (P < 0.001) when the THI increased from 65.62 (P1) to 83.27 (P2). Regression analyses were carried out between THI index and some parameters (HR, RR, MY, DMI, digestibility, plasma concentration of vitamin C) and between RT and same parameters (HR, RR, MY, DMI, digestibility, plasma concentration of vitamin C). Characteristics of regression analyses in the two modes were different as also were R<sup>2</sup> and r (correlation coefficient) of the regressions. R<sup>2</sup> in regressions on RT (R<sup>2</sup> (RT, DMI) = 0.92 (P < 0.01);R<sup>2</sup> (RT, MY) = 0.91 (P < 0.001)) was markedly higher relative to R<sup>2</sup> in regressions on THI (R<sup>2</sup> (THI, DMI) = 0.76 (P < 0.001);R<sup>2 </sup>(THI, MY) = 0.63 (P < 0.001)). The two regressions modes suggest that increasing R<sup>2</sup> in regressions on RT confirms that rectal temperature constitutes a larger component of total variance of responses in dairy cows to hot environmental temperature.
文摘This paper investigates the effects of site based parameters such as ambient temperature, humidity, altitude and heat transfer characteristic of a dual pressure heat recovery system on the performance of the combined cycle power plant within an equatorial environment. The bulk heat utilization and configuration of a dual pressure heat recovery system are investigated. It is observed that the heat system configuration play a vital role in optimizing the combined cycle overall performance, which has proportionality relationship with the operating ambient temperature and relative humidity of the gas turbine. The investigation is carried out within the ambient temperature range of 24℃ to 35℃, relative humidity of 60% to 80%, and a high level steam pressure of 60 bar to 110 bar. The results show that at 24℃ ambient temperature, the heat recovery system has the highest duty of 239.4 MW, the optimum combined cycle power output of 205.52 MW, and overall efficiency of 47.46%. It further indicates that as the ambient temperature increases at an average exhaust gas temperature of 530℃ and mass flow of 470 kg/s, the combined cycle power output and efficiency decrease by 15.5% and 13.7% respectively under the various considerations. This results from a drop in the air and exhaust mass flow as the values of the site parameters increase. The overall results indicate that decreasing the ambient temperature at optimum exhaust gas flow and temperature increases the heat recovery system heat duty performance, the steam generation, overall combined cycle power output and efficiency, which satisfies the research objective.
基金the National Key Research and Development Program of China(No.2016YFD0400304)the Major Science and Technology Projects of Agricultural of Ningbo,China(No.2016C11016).
文摘This study compared the effects of conventional thawing methods(water immersion thawing(WIT,(25±1)℃),natural air thawing(AT,(25±1)℃,relative humidity(RH(65±2)per cent),refrigerator thawing(RT,4℃,RH(80±2)per cent)and low-temperature(LT)combined with high-humidity thawing LT,-1℃to 1℃(LT-1-1),2-4℃(LT2-4),5-7℃(LT5-7)and 8-10℃(LT8-10),RH>95 per cent)on the water-holding capacity,lipid oxidation and biochemical properties of Portunus trituberculatus(P.trituberculatus)myofibrillar protein.The results showed that WIT and AT significantly decreased the water-holding capacity while dramatically increasing lipid oxidation,protein oxidation and degeneration,resulting in serious P.trituberculatus quality deterioration.High humidity was beneficial for P.trituberculatus\.ha\A/\ng.The thawing time of P.trituberculatus under the conditions of LT2-4 was only 39.39 per cent of that of conventional air thawing at 4℃(RT),and the LT2-4 samples not only maintained better water-holding capacity but also had an obviously reduced degree of lipid oxidation,protein oxidation and denaturation.Thawed samples LT2-4 and LT5-7 provided better maintenance of P.trituberculatus quality than the LT-1-1 and LT8-10 samples.The best quality was exhibited after thawing at 2-4℃.The levels of thiobarbituric acid reacting substances,carbonyl content and surface hydrophobicity observably decreased in these samples,while the total sulfhydryl contents dramatically increased compared to those of conventionally thawed samples,indicating lower lipid oxidation and protein oxidation.Moreover,the Ca2+-ATPase activity of the sample thawed at 2-4℃(2.06 μmol Pi/mg prot/h)was markedly higher than that of samples subjected to WIT and AT.The product qualities observed after thawing at-1℃to 1℃,5-7℃and 8-10℃under LT were comparable to that observed by RT.Considering its thawing efficiency and product quality,LT is a suitable method for the thawing of P.trituberculatus,and the ideal thawing conditions were LT at 2-4℃.
基金supported by the National Natural Science Foundation of China (No.61377075)the Training Program for Leading Talents of Universities in Tianjin。
文摘A simple structure optical fiber sensor for relative humidity(RH) and temperature measurement is proposed and verified in this paper, which is based on graphene oxide quantum dots and polyvinyl alcohol(GOQDs-PVA) composite coated tapered no-core fiber(NCF) combined with a fiber Bragg grating(FBG). FBG is insensitive to humidity and sensitive to temperature, which is used to compensate temperature of the sensor. Experimental results show this sensor has humidity sensitivity of 143.27 pm/%RH ranging from 30%RH to 80%RH and the temperature sensitivity of 9.21 pm/℃. The proposed sensor has advantages of simple structure, good repeatability, and good stability, which is expected to be used in both RH and temperature measurement in biological and chemical fields.
