[Objective] This study was conducted to investigate the pathogenicity of Plasmodiophora brassicae on cabbage grown under different temperature and soil pH conditions. [Method] The pathogenicity of P. brassicae were te...[Objective] This study was conducted to investigate the pathogenicity of Plasmodiophora brassicae on cabbage grown under different temperature and soil pH conditions. [Method] The pathogenicity of P. brassicae were tested at seven different temperatures and at six different soil pH values with the resting spore concentration of lx108 (spores/g) in the soil. The plant survival rate and incidence rate of clubroot were investigated after 90 d. [Result] The incidence rate of clubroot on cabbage among the different temperature sets varied in a descending order as follows: 30 ℃〉25 ℃〉20 ℃〉35 ℃〉15 ℃〉10 ℃〉5 ℃ at soil pH value of 6, indicating that the pathogenicity of P. brassicae was weak at 5 and 10 ~(3. The incidence rate increased with soil temperature increasing from 15 to 30 ℃, but decreased at 35 ℃. The incidence rates of clubroot were 80.36%, 100%, 65%, 10.77%, 3.23% and 0% at soil pH 4, 5, 6, 7, 8 and 9 at 25 ℃, respectively. The growth of cabbage was inhibited and the survival rate was reduced at pH 4.The incidence rates of clubroot were low at pH value of 7 and 8, and was 0% at pH 9. The Chinese cabbage grew better at pH value of 5 and 6, but had high incidence rates of clubroot. [Conclusion] The results revealed that the incidence rate of clubroot on cabbage was closely related to the temperature and soil pH.展开更多
The protease activity in digestive tract of young turbot Scophthalmus maximum was studied, and the optimal pH, temperature and NaCl concentration were determined for different portions of the fish’s internal organs. ...The protease activity in digestive tract of young turbot Scophthalmus maximum was studied, and the optimal pH, temperature and NaCl concentration were determined for different portions of the fish’s internal organs. The optimal activity in the fish’s stomach was at pH of 2.2, while that in the intes- tinal extracts was within the alkaline range from 9.5 to 10.0. In hepatopancreas, the optimal pH was in low alkalinity at 8.5. The optimal reaction temperature was above 40℃ in stomach, intestine and hepato- pancreas. With increasing temperature, the pH value increased in stomach, while in the intestine, an op- posite tendency was observed due to combined effect of pH and temperature. NaCl concentration showed inhibitory impact on protein digestion in hepatopancreas. The main protease for protein digestion in turbot seemed to be pepsin. Moreover, the maximum protease activity in different segments of intestine existed in the hindgut.展开更多
The effect of aging temperature on erosion corrosion (E-C) behavior of 17-4PH stainless steels in dilute sulphuric acid slurry containing solid particles was studied by using self-made rotating E-C apparatus. The ef...The effect of aging temperature on erosion corrosion (E-C) behavior of 17-4PH stainless steels in dilute sulphuric acid slurry containing solid particles was studied by using self-made rotating E-C apparatus. The effect of impact velocity on EC behavior of 17 4PH steels at different aging temperatures was analyzed. Surface micrographs of the specimens after E C test were observed by using scanning electron microscope (SEM). The results showed that under the condition of the same solution heat treatment, when aging temperature ranged from 400 ℃ to 610℃, the hardness reached the highest value near the temperature 460℃. The characteristics of E-C for 17-4PH stainless steels at different aging temperatures were as follows: pure erosion (wear) was dominant, corrosion was subordinate and at the same time corrosion promoted erosion. The effect of aging temperature on E-C rate of 17-4PH steels was not significant at low impact velocity, but it was found that E-C resistance of 17-4PH steels aged near 460℃ was the most excellent due to the best precipitation strengthening effect of fine and dispersed e-Cu phase. With a prerequisite of appropriate corrosion resistance, the precipitation hardening could significantly improve the E-C resistance of the materials.展开更多
Coralline algae(CA),a type of primary calcifying producer presented in coastal ecosystems,are considered one of the highly sensitive organisms to marine environmental change.However,experimental studies on coralline a...Coralline algae(CA),a type of primary calcifying producer presented in coastal ecosystems,are considered one of the highly sensitive organisms to marine environmental change.However,experimental studies on coralline algae responses to elevated seawater temperature and reduced pH have documented either contradictory or opposite results.In this study,we analysed the growth and physiological responses of coralline algae Porolithon onkodes to the elevated temperature(30.8°C)and reduced pH(7.8).The aim of this analysis was to observe the direct and combined effects,while elucidating the growth and photosynthesis in this response.It was demonstrated that the algae thallus growth rate and photosynthesis under elevated temperature were depressed by 21.5%and 14.9%respectively.High pCO2 enhanced the growth and photosynthesis of the thallus at ambient temperature,while they were deceased when both temperature and pCO2 were elevated.CA is among the most sensitive organisms to ocean acidification(OA)because of their precipitate high Mg-calcite.We hypothesize that coralline algae could increase their calcification rate in order to counteract the effects of moderate acidification,but offset by the effect of elevated temperature.Accordingly,our results also support the conclusion that global warming(GW)is a stronger threat to algal performance than OA.Our findings are also proposed that coralline algae may be more resilient under OA than GW.展开更多
In this study,different influence mechanisms associated with temperatures and pH values were investigated through cemented paste backfill(CPB)systems.CPB samples were prepared with temperatures ranging from 10 to 50℃...In this study,different influence mechanisms associated with temperatures and pH values were investigated through cemented paste backfill(CPB)systems.CPB samples were prepared with temperatures ranging from 10 to 50℃ in 10℃ increments and pH values of 3,7,and 13.Then,the CPB mixture were subjected to rheological tests,thermogravimetric analysis(TG),derivative thermogravimetry analysis(DTG),Fourier-transform infrared spectroscopy(FT-IR),and scanning electron microscopy(SEM).Results demonstrated that the temperatures had significant effects on the rheological properties of CPB,whereas the effects of pH values were relatively unapparent.Higher temperatures(over 20℃)were prone to bring higher shear stress,yield stress,and apparent viscosity with the same pH value condition.However,an overly high temperature(50℃)cannot raise the apparent viscosity.Non-neutral conditions,for pH values of 3 and 13,could strengthen the shear stress and apparent viscosity at the same temperature.Two different yield stress curves could be discovered by uprising pH values,which also led to apparent viscosity of two various curves under the same temperatures(under 50℃).Microscopically,rheological properties of CPB were affected by temperatures and pH values which enhanced or reduced the cement hydration procedures,rates,products and space structures.展开更多
Methods to optimize the production of gamma-aminobutyric acid (GABA) by Lactobacillus brevis CGMCC 1306 were investigated. Results indicated that cell growth was maximal at pH 5.0, while pH 4.5 was pref-erable to GA...Methods to optimize the production of gamma-aminobutyric acid (GABA) by Lactobacillus brevis CGMCC 1306 were investigated. Results indicated that cell growth was maximal at pH 5.0, while pH 4.5 was pref-erable to GABA formation. The optimal temperature for cell growth (35 °C) was lower than that for GABA forma-tion (40 °C). In a two-stage pH and temperature control fermentation, cultures were maintained at pH 5.0 and 35 °C for 32 h, then adjusted to pH 4.5 and 40 °C, GABA production increased remarkably and reached 474.79 mmol·L-1 at 72 h, while it was 398.63 mmol·L-1 with one stage pH and temperature control process, in which cultivation con-ditions were constantly controlled at pH 5.0 and 35 °C. In order to avoid the inhibition of cell growth at higher L-monosodium glutamate (L-MSG) concentrations, the two-stage control fermentation with substrate feeding strat-egy was applied to GABA production, with 106.87 mmol (20 g) L-MSG supplemented into the shaking-flask at 32 h and 56 h post-inoculation separately. The GABA concentration reached 526.33 mmol·L-1 at 72 h with the fer-mentation volume increased by 38%. These results will provide primary data to realize large-scale production of GABA by L. brevis CGMCC 1306.展开更多
The effects of temperature, light intensity, salinity, and initial pH on the growth and fatty acid composition of Pinguiococcus pyrenoidosus 2078 were studied for eicosapentaenoic acid (EPA) production potential. The ...The effects of temperature, light intensity, salinity, and initial pH on the growth and fatty acid composition of Pinguiococcus pyrenoidosus 2078 were studied for eicosapentaenoic acid (EPA) production potential. The fatty acid composition was assayed by gas chromatography-mass spectrometry, which indicated that the main fatty acids were C14:0, C16:0 and EPA. The highest EPA percentage 20.83% of total fatty acids was obtained at 20℃ with the temperature being set at 20, 24, and 28℃. Under different salinities and light intensities, the highest percentages of total polyunsaturated fatty acids (PUFAs) and EPA were 17.82% and 31.37% of total fatty acids, respectively, which were achieved at salinity 30 and 100μmol photon m-2s-1 illumination. The highest percentages of total PUFAs and EPA were 38.75% and 23.13% of total fatty acids, respectively, which were reached at an initial pH of 6 with the test range being from 5.0 to 9.0.展开更多
The effects of temperature and pH on embryonic development and survival rate of newly hatched larvae of Epinephelus fuscoguttatus were discussed by single factor experiment method. Under a salinity of 31‰, fertilized...The effects of temperature and pH on embryonic development and survival rate of newly hatched larvae of Epinephelus fuscoguttatus were discussed by single factor experiment method. Under a salinity of 31‰, fertilized eggs were incubated at different temperatures (17, 20, 23, 26, 29 (eontrol), 32, 35 ℃ ) and different pH values (5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.4 (control), 8.5, 9.0, 9.5 and 10.0), the development rate of fertilized eggs, hatching rate, deformity rate, survival rate of newly hatched larvae, and optimum temperature and pH ranges for embryonic development were recorded and analyzed. The results showed that the incubation period y required by fertilized eggs was in remarkably negative correlation with temperature x, y =4 017. 3x-15277 , R2 =0. 971 3. At 29 ℃, the hatching rate was the highest, up to 92.00% ; this temperature was corresponding to the lowest deformity rate of newly hatched larvae ( 1.09% ) ; corresponding effective accumulative temperature was also the lowest (437. 410 ℃ . h), and significantly different from other experimental groups (P 〈 0.05 ) ; but on the contrary, corresponding survival rates at 24 and 48 h reached, respectively, 88.03% and 82. 97% which were significantly different from other experimental groups ( P 〈 0.05). At the pH of 8.4 in the CK group and the pH of 8.5 of one experimental group, the embryonic development rates were the highest; con-esponding hatching rates of fertilized eggs were the highest, respectively, of 88.33% and 83.33% which were significantly different from other groups (P 〈 0.05) ; and corresponding survival rates at 24 and 48 h were the highest, and reached 90.84% and 85.03%, respectively. In the pH range of 8.0 - 8.5, the deformity rate of newly hatched larvae was 0. It was indicating that for embryonic development of E. fuscoguttatus, the suitable water temperature value was in the range of 17 - 29 ℃, the optimum value was in the range of 23 -29℃; and the suitable pH value was in the range of 6.5 -9.5, and the optimum value was in the range of 8.0- 8.5.展开更多
A novel class of xanthan-maleic anhydride (Xan-MA)/poly(N-isopropylacrylamide) hybrid hydrogels was designed and synthesized by solution polymerization. The xanthan-based precursor (Xan-MA) was prepared by substitutin...A novel class of xanthan-maleic anhydride (Xan-MA)/poly(N-isopropylacrylamide) hybrid hydrogels was designed and synthesized by solution polymerization. The xanthan-based precursor (Xan-MA) was prepared by substituting the hydroxyl groups in Xan by MA. This Xan-MA precursor was then polymerized with a known temperature sensitive precursor (N-isopropylacrylamide, NIPAAm) to form hybrid hydrogels with a series range of composition ratio of Xan-MA to NIPAAm precursors. These smart hydrogels were characterized by Fourier transform infrared spectroscopy for structural determination, differential scanning calorimertry for thermal property. And maximum swelling ratio, swelling kinetics and temperature response kinetics were studied. The data obtained clearly show that these smart hydrogels are responsive to the external changes of temperature as well as pH value. The magnitudes of smart and hydrogel properties of these hybrid hydrogels depend on the feed composition ratio of the two precursors. With the increase of the content of Xan-MA the maximum swelling ratio, reswelling ratio and thermo-sensitivities increase, and the feed composition ratio of Xan-MA/NIPAAm increases the maximum swelling ratio augment from 13.88 to 23.21. From XMN0, XMN1, XMN3 to XMN5, the lower critical solution temperatures (LCSTs) are 33.02, 36.15, 40.28 and 41.92 ℃, respectively. By changing the composition ratio of these two precursors, the LCST of the hybrid hydrogels could also be adjusted to be or near the body temperature for the potential applications in bioengineering and biotechnology fields.展开更多
Present study was conducted to clarify soil pH and temperature influence on different atrazine bioremediation techniques. For this purpose, sodium citrate, Arthrobactor sp. strain DNS10, sawdust and animal manure were...Present study was conducted to clarify soil pH and temperature influence on different atrazine bioremediation techniques. For this purpose, sodium citrate, Arthrobactor sp. strain DNS10, sawdust and animal manure were selected to clarify their atrazine remediation efficiency under pH 5, 7 and 9 and temperatures 20, 30 and 40℃, respectively. Results showed that atrazine remediation was generally optimized at pH 7 and 30℃ for all the treatments except sodium citrate as soil treated with sawdust was not temperature dependant, but at pH 5 remediation process was determined slower. Atrazine remediation in soil with no additional amendment was only 34%, while in soil treated with sawdust, DNS10, sodium citrate and animal manure were 75.17%, 89%, 74.17% and 76.83% at optimized pH and temperature. Overall atazine removal rate was significantly(≥0.01) higher with increasing in temperature at all the selected pH.展开更多
The pH /temperature dually responsive microgels of interpenetrating polymer network( IPN) structure composed of poly( N-isopropylacrylamide)( PNIPAM) network and poly( acrylic acid)( PAA) network( PNIPAM /PAA IPN micr...The pH /temperature dually responsive microgels of interpenetrating polymer network( IPN) structure composed of poly( N-isopropylacrylamide)( PNIPAM) network and poly( acrylic acid)( PAA) network( PNIPAM /PAA IPN microgels) were synthesized by seed emulsion polymerization. The results obtained by dynamic laser light scattering( DLLS) show that the microgels have good pH /temperature dual sensitivities. The temperature sensitive component and the pH sensitive component inside the microgels have little interference with each other. The rheological properties of the concentrated PNIPAM /PAA IPN microgel dispersions as a function of temperature at pH 4. 0 or 7. 0 were investigated by viscometer,and the results displayed that only at pH 7. 0 the dispersions presented thermoreversible thickening behavior. Then the PNIPAM /PAA fibers were prepared by self-assembly of the PNIPAM /PAA IPN microgels in the ice-crystal templates formed by unidirectional liquid nitrogen freezing method. Field emission scanning electron microscopy( FESEM) images indicate that the PNIPAM /PAA fibers are rounded,randomly orientated and interweaved.展开更多
A series of pH- and temperature-sensitive hydrogels were prepared These gels do not swell at 37℃ and pH 1.4 but swell at 37℃ and pH 7 4.When papain was loaded in these gels. it can be released at 37℃ and pH 7 4in a...A series of pH- and temperature-sensitive hydrogels were prepared These gels do not swell at 37℃ and pH 1.4 but swell at 37℃ and pH 7 4.When papain was loaded in these gels. it can be released at 37℃ and pH 7 4in a high percentage without any loss of activity.展开更多
As per the Essential Climate Variables (ESV) of World Meterological Organisation (WMO), the physical, chemical and biological variables critically contribute to the earth’s climate. Among them, the variables such as ...As per the Essential Climate Variables (ESV) of World Meterological Organisation (WMO), the physical, chemical and biological variables critically contribute to the earth’s climate. Among them, the variables such as temperature and pH in the marine environment may affect seriously and in turn it has an impact on the biota, especially in the intertidal environment, where it has brunt force. According to United Nations Framework Convention on Climate Change (UNFCCC), the datasets should provide the empirical evidence needed to predict the climate change and evoluate the mitigation and adaptation measures. Under this context, a review was carried out to know what extent marine scientists understand this factor and what level the biodiversity was evoluated and its impact was analysed in this article. Based on the existing literature review, it was understood that only a few groups that also only few species from these groups were studied in this aspect. The remaining groups and their species and their basic trophic were not evolved in this aspect. So, the marine scientific community, environmentalist and policy makers should take stock on this aspect and give thrust on this study.展开更多
In this paper, photoinduced electron transfer(PET) phosphoroionophore, N-(1-bromo- 2-naphthylmethyl)-diethanolamine (BND) was synthesized and its phosphorescent characteristics were studied. The experimental results ...In this paper, photoinduced electron transfer(PET) phosphoroionophore, N-(1-bromo- 2-naphthylmethyl)-diethanolamine (BND) was synthesized and its phosphorescent characteristics were studied. The experimental results showed that strong phosphorescence could be observed in b-cyclodextrin aqueous solution only at low pH value. This system combined AND and NOT function to produce a three-input inhibit (INH) logic gate.展开更多
Heat-treated wood has good dimensional stability,corrosion resistance and visual quality,but it is prone to mold,which limits its application.Based on the pH value of heat-treated wood,this study examines the factors ...Heat-treated wood has good dimensional stability,corrosion resistance and visual quality,but it is prone to mold,which limits its application.Based on the pH value of heat-treated wood,this study examines the factors affecting the pathogenesis causing heat-treated wood mold.Normally,the pH value of the heat-treated wood is between 4.38 and 5.10,which is suitable for the growth of mold.However,the pH of the heat-treated copper-containing material is between 6.63 and 7.12,which deviates the treated wood from the comfortable growth conditions for the mold,thereby reducing the occurrence of mold.展开更多
[Objective] This study was conducted to perform harmless resourceful treatment to animal dung. [Method] With fresh cow dung, rabbit dung and bear dung as fermentation materials, the effects of different temperatures a...[Objective] This study was conducted to perform harmless resourceful treatment to animal dung. [Method] With fresh cow dung, rabbit dung and bear dung as fermentation materials, the effects of different temperatures and initial pH values of materials on the biogas production process and biogas yield were investi- gated. [Result] The fermentation of cow dung, rabbit dung and bear dung all pro- duced biogas, and the biogas yield was in positive correlation with carbon-nitrogen ratio. The methane-producing bacteria were very sensitive to the initial pH of fer- mentation material. The adjustment of the temperature and initial pH of fermentation materials had no greater effect on the gas production cycle, but could change the gas production process and total biogas yield. [Conclusion] This study will provide a data basis for the production of biogas from the fermentation of animal dung.展开更多
Cu?Ni nano-alloys were prepared using precursors synthesized by the citrate-gel method. The effects of initial solution pH value and calcination temperature on the composition, crystalline structure, purity, morpholog...Cu?Ni nano-alloys were prepared using precursors synthesized by the citrate-gel method. The effects of initial solution pH value and calcination temperature on the composition, crystalline structure, purity, morphology, homogeneity and grain size of Cu?Ni nanoparticles were investigated. Both the parameters significantly affect the crystalline structure, composition and grain size. Cu?Ni alloys prepared at pH value of 1 do not contain impurities, and their compositions are Cu0.42Ni0.58, Cu0.45Ni0.55 and Cu0.52Ni0.48 reduced at 300, 400 and 500 °C, respectively. The grain size grows with the increase of calcination temperature for the precursor prepared at pH values of 1.6 and 3. The Ni content of the alloys gradually increases with the increase of calcination temperature at pH value of 3.展开更多
基金Supported by Science and Technology Project of Yunnan Province(2014RA061)Special Fund for Modern Agriculture Research System for Rape of Yunnan Province~~
文摘[Objective] This study was conducted to investigate the pathogenicity of Plasmodiophora brassicae on cabbage grown under different temperature and soil pH conditions. [Method] The pathogenicity of P. brassicae were tested at seven different temperatures and at six different soil pH values with the resting spore concentration of lx108 (spores/g) in the soil. The plant survival rate and incidence rate of clubroot were investigated after 90 d. [Result] The incidence rate of clubroot on cabbage among the different temperature sets varied in a descending order as follows: 30 ℃〉25 ℃〉20 ℃〉35 ℃〉15 ℃〉10 ℃〉5 ℃ at soil pH value of 6, indicating that the pathogenicity of P. brassicae was weak at 5 and 10 ~(3. The incidence rate increased with soil temperature increasing from 15 to 30 ℃, but decreased at 35 ℃. The incidence rates of clubroot were 80.36%, 100%, 65%, 10.77%, 3.23% and 0% at soil pH 4, 5, 6, 7, 8 and 9 at 25 ℃, respectively. The growth of cabbage was inhibited and the survival rate was reduced at pH 4.The incidence rates of clubroot were low at pH value of 7 and 8, and was 0% at pH 9. The Chinese cabbage grew better at pH value of 5 and 6, but had high incidence rates of clubroot. [Conclusion] The results revealed that the incidence rate of clubroot on cabbage was closely related to the temperature and soil pH.
文摘The protease activity in digestive tract of young turbot Scophthalmus maximum was studied, and the optimal pH, temperature and NaCl concentration were determined for different portions of the fish’s internal organs. The optimal activity in the fish’s stomach was at pH of 2.2, while that in the intes- tinal extracts was within the alkaline range from 9.5 to 10.0. In hepatopancreas, the optimal pH was in low alkalinity at 8.5. The optimal reaction temperature was above 40℃ in stomach, intestine and hepato- pancreas. With increasing temperature, the pH value increased in stomach, while in the intestine, an op- posite tendency was observed due to combined effect of pH and temperature. NaCl concentration showed inhibitory impact on protein digestion in hepatopancreas. The main protease for protein digestion in turbot seemed to be pepsin. Moreover, the maximum protease activity in different segments of intestine existed in the hindgut.
文摘The effect of aging temperature on erosion corrosion (E-C) behavior of 17-4PH stainless steels in dilute sulphuric acid slurry containing solid particles was studied by using self-made rotating E-C apparatus. The effect of impact velocity on EC behavior of 17 4PH steels at different aging temperatures was analyzed. Surface micrographs of the specimens after E C test were observed by using scanning electron microscope (SEM). The results showed that under the condition of the same solution heat treatment, when aging temperature ranged from 400 ℃ to 610℃, the hardness reached the highest value near the temperature 460℃. The characteristics of E-C for 17-4PH stainless steels at different aging temperatures were as follows: pure erosion (wear) was dominant, corrosion was subordinate and at the same time corrosion promoted erosion. The effect of aging temperature on E-C rate of 17-4PH steels was not significant at low impact velocity, but it was found that E-C resistance of 17-4PH steels aged near 460℃ was the most excellent due to the best precipitation strengthening effect of fine and dispersed e-Cu phase. With a prerequisite of appropriate corrosion resistance, the precipitation hardening could significantly improve the E-C resistance of the materials.
基金The National Natural Science Foundation of China(NSFC)under contract Nos 41306144 and 41676150the National Key Research and Development Plan under contract No.2017YFC0506301+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA13020402the Guangdong Basic and Applied Basic Research Foundation under contract No.2019A1515011532
文摘Coralline algae(CA),a type of primary calcifying producer presented in coastal ecosystems,are considered one of the highly sensitive organisms to marine environmental change.However,experimental studies on coralline algae responses to elevated seawater temperature and reduced pH have documented either contradictory or opposite results.In this study,we analysed the growth and physiological responses of coralline algae Porolithon onkodes to the elevated temperature(30.8°C)and reduced pH(7.8).The aim of this analysis was to observe the direct and combined effects,while elucidating the growth and photosynthesis in this response.It was demonstrated that the algae thallus growth rate and photosynthesis under elevated temperature were depressed by 21.5%and 14.9%respectively.High pCO2 enhanced the growth and photosynthesis of the thallus at ambient temperature,while they were deceased when both temperature and pCO2 were elevated.CA is among the most sensitive organisms to ocean acidification(OA)because of their precipitate high Mg-calcite.We hypothesize that coralline algae could increase their calcification rate in order to counteract the effects of moderate acidification,but offset by the effect of elevated temperature.Accordingly,our results also support the conclusion that global warming(GW)is a stronger threat to algal performance than OA.Our findings are also proposed that coralline algae may be more resilient under OA than GW.
基金Project(2019zzts678)supported by the Fundamental Research Funds for the Central Universities,China。
文摘In this study,different influence mechanisms associated with temperatures and pH values were investigated through cemented paste backfill(CPB)systems.CPB samples were prepared with temperatures ranging from 10 to 50℃ in 10℃ increments and pH values of 3,7,and 13.Then,the CPB mixture were subjected to rheological tests,thermogravimetric analysis(TG),derivative thermogravimetry analysis(DTG),Fourier-transform infrared spectroscopy(FT-IR),and scanning electron microscopy(SEM).Results demonstrated that the temperatures had significant effects on the rheological properties of CPB,whereas the effects of pH values were relatively unapparent.Higher temperatures(over 20℃)were prone to bring higher shear stress,yield stress,and apparent viscosity with the same pH value condition.However,an overly high temperature(50℃)cannot raise the apparent viscosity.Non-neutral conditions,for pH values of 3 and 13,could strengthen the shear stress and apparent viscosity at the same temperature.Two different yield stress curves could be discovered by uprising pH values,which also led to apparent viscosity of two various curves under the same temperatures(under 50℃).Microscopically,rheological properties of CPB were affected by temperatures and pH values which enhanced or reduced the cement hydration procedures,rates,products and space structures.
基金Supported by the National'Naturai Science Foundation of China (30970638, 21176220 and 31240054), Zhejiang Provincial Natural Science Foundation (Z13B06008) and the National Basic Research Program of China (2007CB714305).
文摘Methods to optimize the production of gamma-aminobutyric acid (GABA) by Lactobacillus brevis CGMCC 1306 were investigated. Results indicated that cell growth was maximal at pH 5.0, while pH 4.5 was pref-erable to GABA formation. The optimal temperature for cell growth (35 °C) was lower than that for GABA forma-tion (40 °C). In a two-stage pH and temperature control fermentation, cultures were maintained at pH 5.0 and 35 °C for 32 h, then adjusted to pH 4.5 and 40 °C, GABA production increased remarkably and reached 474.79 mmol·L-1 at 72 h, while it was 398.63 mmol·L-1 with one stage pH and temperature control process, in which cultivation con-ditions were constantly controlled at pH 5.0 and 35 °C. In order to avoid the inhibition of cell growth at higher L-monosodium glutamate (L-MSG) concentrations, the two-stage control fermentation with substrate feeding strat-egy was applied to GABA production, with 106.87 mmol (20 g) L-MSG supplemented into the shaking-flask at 32 h and 56 h post-inoculation separately. The GABA concentration reached 526.33 mmol·L-1 at 72 h with the fer-mentation volume increased by 38%. These results will provide primary data to realize large-scale production of GABA by L. brevis CGMCC 1306.
基金supported by the Scientific Research Foundation of Ji’nan University (No. 50624068)the Fundamental Research Funds for the Central Universities (No. 11609318)the Project of Science and Technology Development Plan, Science and Technology Bureau of Hengyang (2010KJ25)
文摘The effects of temperature, light intensity, salinity, and initial pH on the growth and fatty acid composition of Pinguiococcus pyrenoidosus 2078 were studied for eicosapentaenoic acid (EPA) production potential. The fatty acid composition was assayed by gas chromatography-mass spectrometry, which indicated that the main fatty acids were C14:0, C16:0 and EPA. The highest EPA percentage 20.83% of total fatty acids was obtained at 20℃ with the temperature being set at 20, 24, and 28℃. Under different salinities and light intensities, the highest percentages of total polyunsaturated fatty acids (PUFAs) and EPA were 17.82% and 31.37% of total fatty acids, respectively, which were achieved at salinity 30 and 100μmol photon m-2s-1 illumination. The highest percentages of total PUFAs and EPA were 38.75% and 23.13% of total fatty acids, respectively, which were reached at an initial pH of 6 with the test range being from 5.0 to 9.0.
基金Supported by Special Fund for Construction of Hainan Key Laboratory and Engineering Technical Research Center(gczx2013005)Special Fund for Technology Development by Scientific Research Institutes of Hainan Province(KYYS-2014-59)+1 种基金Special Fund for Application Technology Development and Demonstration(ZDXM2015025)Hainan Provincial-level Department Budget Project
文摘The effects of temperature and pH on embryonic development and survival rate of newly hatched larvae of Epinephelus fuscoguttatus were discussed by single factor experiment method. Under a salinity of 31‰, fertilized eggs were incubated at different temperatures (17, 20, 23, 26, 29 (eontrol), 32, 35 ℃ ) and different pH values (5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.4 (control), 8.5, 9.0, 9.5 and 10.0), the development rate of fertilized eggs, hatching rate, deformity rate, survival rate of newly hatched larvae, and optimum temperature and pH ranges for embryonic development were recorded and analyzed. The results showed that the incubation period y required by fertilized eggs was in remarkably negative correlation with temperature x, y =4 017. 3x-15277 , R2 =0. 971 3. At 29 ℃, the hatching rate was the highest, up to 92.00% ; this temperature was corresponding to the lowest deformity rate of newly hatched larvae ( 1.09% ) ; corresponding effective accumulative temperature was also the lowest (437. 410 ℃ . h), and significantly different from other experimental groups (P 〈 0.05 ) ; but on the contrary, corresponding survival rates at 24 and 48 h reached, respectively, 88.03% and 82. 97% which were significantly different from other experimental groups ( P 〈 0.05). At the pH of 8.4 in the CK group and the pH of 8.5 of one experimental group, the embryonic development rates were the highest; con-esponding hatching rates of fertilized eggs were the highest, respectively, of 88.33% and 83.33% which were significantly different from other groups (P 〈 0.05) ; and corresponding survival rates at 24 and 48 h were the highest, and reached 90.84% and 85.03%, respectively. In the pH range of 8.0 - 8.5, the deformity rate of newly hatched larvae was 0. It was indicating that for embryonic development of E. fuscoguttatus, the suitable water temperature value was in the range of 17 - 29 ℃, the optimum value was in the range of 23 -29℃; and the suitable pH value was in the range of 6.5 -9.5, and the optimum value was in the range of 8.0- 8.5.
文摘A novel class of xanthan-maleic anhydride (Xan-MA)/poly(N-isopropylacrylamide) hybrid hydrogels was designed and synthesized by solution polymerization. The xanthan-based precursor (Xan-MA) was prepared by substituting the hydroxyl groups in Xan by MA. This Xan-MA precursor was then polymerized with a known temperature sensitive precursor (N-isopropylacrylamide, NIPAAm) to form hybrid hydrogels with a series range of composition ratio of Xan-MA to NIPAAm precursors. These smart hydrogels were characterized by Fourier transform infrared spectroscopy for structural determination, differential scanning calorimertry for thermal property. And maximum swelling ratio, swelling kinetics and temperature response kinetics were studied. The data obtained clearly show that these smart hydrogels are responsive to the external changes of temperature as well as pH value. The magnitudes of smart and hydrogel properties of these hybrid hydrogels depend on the feed composition ratio of the two precursors. With the increase of the content of Xan-MA the maximum swelling ratio, reswelling ratio and thermo-sensitivities increase, and the feed composition ratio of Xan-MA/NIPAAm increases the maximum swelling ratio augment from 13.88 to 23.21. From XMN0, XMN1, XMN3 to XMN5, the lower critical solution temperatures (LCSTs) are 33.02, 36.15, 40.28 and 41.92 ℃, respectively. By changing the composition ratio of these two precursors, the LCST of the hybrid hydrogels could also be adjusted to be or near the body temperature for the potential applications in bioengineering and biotechnology fields.
基金Supported by the University Science and Technology Innovation Team Construction Projects of Heilongjiang Province(2013 TD003)
文摘Present study was conducted to clarify soil pH and temperature influence on different atrazine bioremediation techniques. For this purpose, sodium citrate, Arthrobactor sp. strain DNS10, sawdust and animal manure were selected to clarify their atrazine remediation efficiency under pH 5, 7 and 9 and temperatures 20, 30 and 40℃, respectively. Results showed that atrazine remediation was generally optimized at pH 7 and 30℃ for all the treatments except sodium citrate as soil treated with sawdust was not temperature dependant, but at pH 5 remediation process was determined slower. Atrazine remediation in soil with no additional amendment was only 34%, while in soil treated with sawdust, DNS10, sodium citrate and animal manure were 75.17%, 89%, 74.17% and 76.83% at optimized pH and temperature. Overall atazine removal rate was significantly(≥0.01) higher with increasing in temperature at all the selected pH.
基金National Natural Science Foundations of China(Nos.51073033,51373030)the Fundamental Research Funds for the Central Universities,China(No.2232014D3-43)
文摘The pH /temperature dually responsive microgels of interpenetrating polymer network( IPN) structure composed of poly( N-isopropylacrylamide)( PNIPAM) network and poly( acrylic acid)( PAA) network( PNIPAM /PAA IPN microgels) were synthesized by seed emulsion polymerization. The results obtained by dynamic laser light scattering( DLLS) show that the microgels have good pH /temperature dual sensitivities. The temperature sensitive component and the pH sensitive component inside the microgels have little interference with each other. The rheological properties of the concentrated PNIPAM /PAA IPN microgel dispersions as a function of temperature at pH 4. 0 or 7. 0 were investigated by viscometer,and the results displayed that only at pH 7. 0 the dispersions presented thermoreversible thickening behavior. Then the PNIPAM /PAA fibers were prepared by self-assembly of the PNIPAM /PAA IPN microgels in the ice-crystal templates formed by unidirectional liquid nitrogen freezing method. Field emission scanning electron microscopy( FESEM) images indicate that the PNIPAM /PAA fibers are rounded,randomly orientated and interweaved.
文摘A series of pH- and temperature-sensitive hydrogels were prepared These gels do not swell at 37℃ and pH 1.4 but swell at 37℃ and pH 7 4.When papain was loaded in these gels. it can be released at 37℃ and pH 7 4in a high percentage without any loss of activity.
文摘As per the Essential Climate Variables (ESV) of World Meterological Organisation (WMO), the physical, chemical and biological variables critically contribute to the earth’s climate. Among them, the variables such as temperature and pH in the marine environment may affect seriously and in turn it has an impact on the biota, especially in the intertidal environment, where it has brunt force. According to United Nations Framework Convention on Climate Change (UNFCCC), the datasets should provide the empirical evidence needed to predict the climate change and evoluate the mitigation and adaptation measures. Under this context, a review was carried out to know what extent marine scientists understand this factor and what level the biodiversity was evoluated and its impact was analysed in this article. Based on the existing literature review, it was understood that only a few groups that also only few species from these groups were studied in this aspect. The remaining groups and their species and their basic trophic were not evolved in this aspect. So, the marine scientific community, environmentalist and policy makers should take stock on this aspect and give thrust on this study.
文摘In this paper, photoinduced electron transfer(PET) phosphoroionophore, N-(1-bromo- 2-naphthylmethyl)-diethanolamine (BND) was synthesized and its phosphorescent characteristics were studied. The experimental results showed that strong phosphorescence could be observed in b-cyclodextrin aqueous solution only at low pH value. This system combined AND and NOT function to produce a three-input inhibit (INH) logic gate.
基金Provincial Science and Technology Research Project of Guangdong(2014A040401043)
文摘Heat-treated wood has good dimensional stability,corrosion resistance and visual quality,but it is prone to mold,which limits its application.Based on the pH value of heat-treated wood,this study examines the factors affecting the pathogenesis causing heat-treated wood mold.Normally,the pH value of the heat-treated wood is between 4.38 and 5.10,which is suitable for the growth of mold.However,the pH of the heat-treated copper-containing material is between 6.63 and 7.12,which deviates the treated wood from the comfortable growth conditions for the mold,thereby reducing the occurrence of mold.
文摘[Objective] This study was conducted to perform harmless resourceful treatment to animal dung. [Method] With fresh cow dung, rabbit dung and bear dung as fermentation materials, the effects of different temperatures and initial pH values of materials on the biogas production process and biogas yield were investi- gated. [Result] The fermentation of cow dung, rabbit dung and bear dung all pro- duced biogas, and the biogas yield was in positive correlation with carbon-nitrogen ratio. The methane-producing bacteria were very sensitive to the initial pH of fer- mentation material. The adjustment of the temperature and initial pH of fermentation materials had no greater effect on the gas production cycle, but could change the gas production process and total biogas yield. [Conclusion] This study will provide a data basis for the production of biogas from the fermentation of animal dung.
基金Universidad Nacional de San Luis, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)Fondo para la Investigación Científica y Técnológica (FONCy T), Argentina,for their financial support
文摘Cu?Ni nano-alloys were prepared using precursors synthesized by the citrate-gel method. The effects of initial solution pH value and calcination temperature on the composition, crystalline structure, purity, morphology, homogeneity and grain size of Cu?Ni nanoparticles were investigated. Both the parameters significantly affect the crystalline structure, composition and grain size. Cu?Ni alloys prepared at pH value of 1 do not contain impurities, and their compositions are Cu0.42Ni0.58, Cu0.45Ni0.55 and Cu0.52Ni0.48 reduced at 300, 400 and 500 °C, respectively. The grain size grows with the increase of calcination temperature for the precursor prepared at pH values of 1.6 and 3. The Ni content of the alloys gradually increases with the increase of calcination temperature at pH value of 3.