factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB species diatom Skeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, ...factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB species diatom Skeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, 25, 32℃), irradiance ((0.02, 0.08, 0.3, 1.6)×10 16 quanta/(s·cm 2)) and salinity (10, 18, 25, 30, 35) significantly influenced the growth of this species. There were interactive effects between any two of and among all three physical factors on the growth. In the experiment, the most optimal growth condition for S. costatum was temparature of 25℃, salinity of 18-35 and irradiance of 1.6×10 16 quanta/(s·cm 2). The results indicated S. costatum could divide at higher rate and were more likely to bloom under high temperature and high illumination from spring to fall. It was able to distribute widely in ocean and estuary due to its adaptation to a wide range of salinities.展开更多
Fragment containing the whole riboflavin(rib)operons of B.cereus ATCC14579 was detected from GenBank and annotated.The rib operon of ATCC14579 was cloned with Pn,its native promoter,or with P43,the vegetative growth p...Fragment containing the whole riboflavin(rib)operons of B.cereus ATCC14579 was detected from GenBank and annotated.The rib operon of ATCC14579 was cloned with Pn,its native promoter,or with P43,the vegetative growth promoter,into the plasmid.Expression analysis showed that heterologous rib operon was operative in B.subtilis.Integrative plasmid with P43-rib fragment was integrated into the chromosome of B.subtilis RH33,yielding transformant B.subtilis PY.With optimized medium components,4.3 g·L -1 of riboflavin was achieved in batch culture of B.subtilis PY,which was 27%enhancement compared to the host strain.Real-time reverse transcription polymerase chain reaction(RT-PCR)analysis indicated that the transcriptional level of ribA maintained 2.8-fold higher with the expression of herterologous rib operon.Furthermore,the stability of B.subtilis PY was increased form 45%to 87%.The high transcriptional level of rib gene and higher stability of B.subtilis PY could explain the increased riboflavin production.展开更多
Many persons worldwide are deficient in micronutrients, two of the most common being vitamin A and iron. Fortification of staple food is a commonly used and effective method of boosting micronutrient intake. Wheat flo...Many persons worldwide are deficient in micronutrients, two of the most common being vitamin A and iron. Fortification of staple food is a commonly used and effective method of boosting micronutrient intake. Wheat flour is widely used around the world and makes a good vehicle for fortification, but there is a lack of studies on the storage stability of fortified wheat flour. In this study, we fortified wheat flour with elevated levels of vitamin A and three sources of iron and stored it for up to 16 weeks at refrigerated or room temperature or elevated temperature. The rate of disappearance of vitamin A was monitored by high pressure liquid chromatography, and the rate of disappearance was fotmd to be directly proportional to the duration of storage and storage temperature. Higher temperatures contributed to greater loss of vitamin A. Iron, regardless of source, did not play a major role in contributing to the rate of vitamin A loss. Flour functionality was assessed by baking loaves of bread from the stored flour and assessing physical properties as well as subjecting the loaves to an expert sensory panel. Functionality also changed with time and temperature of storage, but sensory analysis found that these changes were not detrimental to the quality of bread baked from the stored flours. Trained sensory panelists found that breads baked from flours fortified with ferrous sulfate and stored at the three temperatures for times up to eight weeks were markedly different from fortified flours using hydrogen reduced irons.展开更多
Nutrition is an important factor for the growth and development of plants. Among the main nutritional elements, there are nitrogen (N) and calcium (Ca). The N comes from two forms of inorganic ions, ammonium (NH...Nutrition is an important factor for the growth and development of plants. Among the main nutritional elements, there are nitrogen (N) and calcium (Ca). The N comes from two forms of inorganic ions, ammonium (NH4+) and nitrate (NO3) whose functions in the plant are the increase in leaf area and improving the succulence of many crops, among other essential physiological processes. Both the deficit and excess NO3- have a negative impact on plants increasing susceptibility to insect pests and pathogens, while Ca as divalent ion absorbed Ca2+ plays an important role in control of physiological disorders and the resistance of plants to diseases to increase the mechanical strength. The N and Ca have a close relationship in the nutritional role of the plant, because the Ca absorption acting nitrates, so that a proper balance affects plants better growth and higher strength.展开更多
Using directional distance function and nonparametric data envelopment analys&, th& paper estimates the environmental total factor productivity (ETFP) of energy-intensive industries in China from 1995 to 2010, and...Using directional distance function and nonparametric data envelopment analys&, th& paper estimates the environmental total factor productivity (ETFP) of energy-intensive industries in China from 1995 to 2010, and performs an empirical analysis on factors affecting ETFP growth after studying the differences of energy-intensive industries ' ETFP by industries and provinces. The findings include the following: energy-intensive industries 'ETFP growth is mainly driven by technical progress; China, at its current development stage, still has the potential to raise the productivity of its energy- intensive industries. By estimating the provincial data, we find that the ETFP growth of different provinces converge at different levels. Further market liberalization, increased FDl flows and reductions in energy intensity will help to improve each province's ETFP growth. In addition, increasing investment in energy saving and emissions reduction and improving corporate environmental management capacity can help to reduce a company's short-term cost of complying with environmental regulations.展开更多
The high cycle fatigue response of a high V-alloyed powder metallurgy tool steel (AISI 11) with different inclusion sizes was studied. Two materials of this grade at a similar hardness of about HRC 60 were subjected...The high cycle fatigue response of a high V-alloyed powder metallurgy tool steel (AISI 11) with different inclusion sizes was studied. Two materials of this grade at a similar hardness of about HRC 60 were subjected to axial loading fatigue tests, tensile tests and fracture toughness measurements to investigate their mechanical properties. Large inclusion above 70 ~rn is indicated to be responsible for the tensile fracture which happens before yielding. The fatigue strength obtained up to 107 cycles is found to decrease from approximately 1 538 MPa to 1000 MPa with the inclusion size increasing above 30 Izm. The internally induced crack initiation is mainly attributed to the surface compressive residual stress of 300-450 MPa. Fractographic evaluation demonstrates that the crack initiation and propagation controlling factors of the two materials are almost the same, indicating that the two factors would be insignificantly affected by the inclusion size level. Paris sizes of the two materials both show a tendency to decrease as the ratio of stress intensity factor of crack origin to factor of fish-eye increases. The investigation into the relationship between stress intensity factors and fatigue life of the two materials further indicates that the high cycle fatigue behavior of AISI 11 is controlled by crack propagation.展开更多
Objective: To investigate the anti-inflammatory effect of erythropoietin (EPO) pretreatment on cardiomyocytes exposed to hypoxialreoxygenation injury (H/R) and explore the possible mechanism. Methods: The cultur...Objective: To investigate the anti-inflammatory effect of erythropoietin (EPO) pretreatment on cardiomyocytes exposed to hypoxialreoxygenation injury (H/R) and explore the possible mechanism. Methods: The cultured neonatal rats' ventricular cardiomyocytes were divided randomly into 4 groups, control group (C group), EPO pretreatment group (E group), EPO and pyrrolidine dithiocarbamate (PDTC) pretreatment group (EP group) and PDTC pretreatment group (P group). After 24 hours' pretreatment, the cardiomyocytes were exposed to H/R. After pretreatment and H/R, the expression of tumor necrosis factor- α (TNF- α ) gene in all the groups was detected by RT-PCR and Western blot. The nuclear factor- κ B (NF- κB) activity was detected by electrophoretic mobility shift assay (EMSA) and the inhibitor- κB α (Ⅰ- κB α) protein level was detected by Western blot. Results: The decrement of Ⅰ- κB a protein and the increasing NF- KB activity were found in cardiomyocytes pretreated with EPO before H/R compared to other groups (t=3.321, 4.183, P〈0.01). However, after H/R, NF- κB activity and expression of TNF- α gene were significantly reduced, Ⅰ- κB a protein expression was increased in cardiomyocytes of E group compared to other groups (t=-3.425, 3.687, 3.454, P〈0.01). All theses changes caused by EPO pretreatment were eliminated by the intervention of PDTC (an antagonist to NF- κB) during pretreatment. Conclusions: EPO pretreatment can inhibit the activation of NF- κB and upregulation of TNF- α gene in cardiomyocytes exposed to H/R through a negative feedback of NF- κB signaling pathway, and thus produces the anti-inflammatory effect. This might be one of the ways EPO produces the anti-inflammatory effect.展开更多
Background and aims: Ingestion of paraquat (PQ), a widely used herbicide, can cause severe toxicity in humans, leading to a poor survival rate and prognosis. One of the main causes of death by PQ is PQ-induced pul-...Background and aims: Ingestion of paraquat (PQ), a widely used herbicide, can cause severe toxicity in humans, leading to a poor survival rate and prognosis. One of the main causes of death by PQ is PQ-induced pul- monary fibrosis, for which there are no effective therapies. The aim of this study was to evaluate the effects of ra- pamycin (PAPA) on inhibiting PQ-induced pulmonary fibrosis in mice and to explore its possible mechanisms. Methods: Male C57BL/6J mice were exposed to either saline (control group) or PQ (10 mg/kg body weight, intraper- itoneally; test group). The test group was divided into four subgroups: a PQ group (PQ-exposed, non-treated), a PQ+RAPA group (PQ-exposed, treated with RAPA at I mg/kg intragastrically), a PQ+MP group (PQ-exposed, treated with methylprednisolone (MP) at 30 mg/kg intraperitoneally), and a PQ+MP+RAPA group (PQ-exposed, treated with MP at 30 mg/kg intraperitoneally and with PAPA at 1 mg/kg intragastrically). The survival rate and body weight of all the mice were recorded every day. Three mice in each group were sacrificed at 14 d and the rest at 28 d after intox- ication. Lung tissues were excised and stained with hematoxylin-eosin (H&E) and Masson's trichrome stain for his- topathological analysis. The hydroxyproline (HYP) content in lung tissues was detected using an enzyme-linked im- munosorbent assay (ELISA) kit. The expression of transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) in lung tissues was detected by immunohistochemical staining and Western blotting. Results: A mice model of PQ-induced pulmonary fibrosis was established. Histological examination of lung tissues showed that PAPA treatment moderated the pathological changes of pulmonary fibrosis, including alveolar collapse and interstitial collagen depo- sition. HYP content in lung tissues increased soon after PQ intoxication but had decreased significantly by the 28th day after PAPA treatment. Immunohistochemical staining and Western blotting showed that PAPA treatment significantly down-regulated the enhanced levels of TGF-β1 and e-SMA in lung tissues caused by PQ exposure. However, PAPA treatment alone could not significantly ameliorate the lower survival rate and weight loss of treated mice. MP treatment enhanced the survival rate, but had no significant effects on attenuating PQ-induced pulmonary fibrosis or reducing the expression of TGF-β1 and a-SMA. Conclusions: This study demonstrates that PAPA treatment effectively suppresses PQ-induced alveolar collapse and collagen deposition in lung tissues through reducing the expression of TGF-β1 and a-SMA. Thus, RAPA has potential value in the treatment of PQ-induced pulmonary fibrosis.展开更多
文摘factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB species diatom Skeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, 25, 32℃), irradiance ((0.02, 0.08, 0.3, 1.6)×10 16 quanta/(s·cm 2)) and salinity (10, 18, 25, 30, 35) significantly influenced the growth of this species. There were interactive effects between any two of and among all three physical factors on the growth. In the experiment, the most optimal growth condition for S. costatum was temparature of 25℃, salinity of 18-35 and irradiance of 1.6×10 16 quanta/(s·cm 2). The results indicated S. costatum could divide at higher rate and were more likely to bloom under high temperature and high illumination from spring to fall. It was able to distribute widely in ocean and estuary due to its adaptation to a wide range of salinities.
基金Supported by the National Natural Science Foundation of China(20536040) the State Key Development Program for Basic Research of China(2007CB707802) the Development Project of Science and Technology of Tianjin(05YFGZGX04500)
文摘Fragment containing the whole riboflavin(rib)operons of B.cereus ATCC14579 was detected from GenBank and annotated.The rib operon of ATCC14579 was cloned with Pn,its native promoter,or with P43,the vegetative growth promoter,into the plasmid.Expression analysis showed that heterologous rib operon was operative in B.subtilis.Integrative plasmid with P43-rib fragment was integrated into the chromosome of B.subtilis RH33,yielding transformant B.subtilis PY.With optimized medium components,4.3 g·L -1 of riboflavin was achieved in batch culture of B.subtilis PY,which was 27%enhancement compared to the host strain.Real-time reverse transcription polymerase chain reaction(RT-PCR)analysis indicated that the transcriptional level of ribA maintained 2.8-fold higher with the expression of herterologous rib operon.Furthermore,the stability of B.subtilis PY was increased form 45%to 87%.The high transcriptional level of rib gene and higher stability of B.subtilis PY could explain the increased riboflavin production.
文摘Many persons worldwide are deficient in micronutrients, two of the most common being vitamin A and iron. Fortification of staple food is a commonly used and effective method of boosting micronutrient intake. Wheat flour is widely used around the world and makes a good vehicle for fortification, but there is a lack of studies on the storage stability of fortified wheat flour. In this study, we fortified wheat flour with elevated levels of vitamin A and three sources of iron and stored it for up to 16 weeks at refrigerated or room temperature or elevated temperature. The rate of disappearance of vitamin A was monitored by high pressure liquid chromatography, and the rate of disappearance was fotmd to be directly proportional to the duration of storage and storage temperature. Higher temperatures contributed to greater loss of vitamin A. Iron, regardless of source, did not play a major role in contributing to the rate of vitamin A loss. Flour functionality was assessed by baking loaves of bread from the stored flour and assessing physical properties as well as subjecting the loaves to an expert sensory panel. Functionality also changed with time and temperature of storage, but sensory analysis found that these changes were not detrimental to the quality of bread baked from the stored flours. Trained sensory panelists found that breads baked from flours fortified with ferrous sulfate and stored at the three temperatures for times up to eight weeks were markedly different from fortified flours using hydrogen reduced irons.
文摘Nutrition is an important factor for the growth and development of plants. Among the main nutritional elements, there are nitrogen (N) and calcium (Ca). The N comes from two forms of inorganic ions, ammonium (NH4+) and nitrate (NO3) whose functions in the plant are the increase in leaf area and improving the succulence of many crops, among other essential physiological processes. Both the deficit and excess NO3- have a negative impact on plants increasing susceptibility to insect pests and pathogens, while Ca as divalent ion absorbed Ca2+ plays an important role in control of physiological disorders and the resistance of plants to diseases to increase the mechanical strength. The N and Ca have a close relationship in the nutritional role of the plant, because the Ca absorption acting nitrates, so that a proper balance affects plants better growth and higher strength.
文摘Using directional distance function and nonparametric data envelopment analys&, th& paper estimates the environmental total factor productivity (ETFP) of energy-intensive industries in China from 1995 to 2010, and performs an empirical analysis on factors affecting ETFP growth after studying the differences of energy-intensive industries ' ETFP by industries and provinces. The findings include the following: energy-intensive industries 'ETFP growth is mainly driven by technical progress; China, at its current development stage, still has the potential to raise the productivity of its energy- intensive industries. By estimating the provincial data, we find that the ETFP growth of different provinces converge at different levels. Further market liberalization, increased FDl flows and reductions in energy intensity will help to improve each province's ETFP growth. In addition, increasing investment in energy saving and emissions reduction and improving corporate environmental management capacity can help to reduce a company's short-term cost of complying with environmental regulations.
基金Project(2007BAE51B05)supported by the National Key Technologies Research and Development Program of China
文摘The high cycle fatigue response of a high V-alloyed powder metallurgy tool steel (AISI 11) with different inclusion sizes was studied. Two materials of this grade at a similar hardness of about HRC 60 were subjected to axial loading fatigue tests, tensile tests and fracture toughness measurements to investigate their mechanical properties. Large inclusion above 70 ~rn is indicated to be responsible for the tensile fracture which happens before yielding. The fatigue strength obtained up to 107 cycles is found to decrease from approximately 1 538 MPa to 1000 MPa with the inclusion size increasing above 30 Izm. The internally induced crack initiation is mainly attributed to the surface compressive residual stress of 300-450 MPa. Fractographic evaluation demonstrates that the crack initiation and propagation controlling factors of the two materials are almost the same, indicating that the two factors would be insignificantly affected by the inclusion size level. Paris sizes of the two materials both show a tendency to decrease as the ratio of stress intensity factor of crack origin to factor of fish-eye increases. The investigation into the relationship between stress intensity factors and fatigue life of the two materials further indicates that the high cycle fatigue behavior of AISI 11 is controlled by crack propagation.
文摘Objective: To investigate the anti-inflammatory effect of erythropoietin (EPO) pretreatment on cardiomyocytes exposed to hypoxialreoxygenation injury (H/R) and explore the possible mechanism. Methods: The cultured neonatal rats' ventricular cardiomyocytes were divided randomly into 4 groups, control group (C group), EPO pretreatment group (E group), EPO and pyrrolidine dithiocarbamate (PDTC) pretreatment group (EP group) and PDTC pretreatment group (P group). After 24 hours' pretreatment, the cardiomyocytes were exposed to H/R. After pretreatment and H/R, the expression of tumor necrosis factor- α (TNF- α ) gene in all the groups was detected by RT-PCR and Western blot. The nuclear factor- κ B (NF- κB) activity was detected by electrophoretic mobility shift assay (EMSA) and the inhibitor- κB α (Ⅰ- κB α) protein level was detected by Western blot. Results: The decrement of Ⅰ- κB a protein and the increasing NF- KB activity were found in cardiomyocytes pretreated with EPO before H/R compared to other groups (t=3.321, 4.183, P〈0.01). However, after H/R, NF- κB activity and expression of TNF- α gene were significantly reduced, Ⅰ- κB a protein expression was increased in cardiomyocytes of E group compared to other groups (t=-3.425, 3.687, 3.454, P〈0.01). All theses changes caused by EPO pretreatment were eliminated by the intervention of PDTC (an antagonist to NF- κB) during pretreatment. Conclusions: EPO pretreatment can inhibit the activation of NF- κB and upregulation of TNF- α gene in cardiomyocytes exposed to H/R through a negative feedback of NF- κB signaling pathway, and thus produces the anti-inflammatory effect. This might be one of the ways EPO produces the anti-inflammatory effect.
基金supported by the National Key Technology R&D Program of China(No.2011BAI10B07)the National Basic Research Program(973)of China(No.2012CB517603)the National High-Tech R&D Program(863)of China(No.2012AA02A512)
文摘Background and aims: Ingestion of paraquat (PQ), a widely used herbicide, can cause severe toxicity in humans, leading to a poor survival rate and prognosis. One of the main causes of death by PQ is PQ-induced pul- monary fibrosis, for which there are no effective therapies. The aim of this study was to evaluate the effects of ra- pamycin (PAPA) on inhibiting PQ-induced pulmonary fibrosis in mice and to explore its possible mechanisms. Methods: Male C57BL/6J mice were exposed to either saline (control group) or PQ (10 mg/kg body weight, intraper- itoneally; test group). The test group was divided into four subgroups: a PQ group (PQ-exposed, non-treated), a PQ+RAPA group (PQ-exposed, treated with RAPA at I mg/kg intragastrically), a PQ+MP group (PQ-exposed, treated with methylprednisolone (MP) at 30 mg/kg intraperitoneally), and a PQ+MP+RAPA group (PQ-exposed, treated with MP at 30 mg/kg intraperitoneally and with PAPA at 1 mg/kg intragastrically). The survival rate and body weight of all the mice were recorded every day. Three mice in each group were sacrificed at 14 d and the rest at 28 d after intox- ication. Lung tissues were excised and stained with hematoxylin-eosin (H&E) and Masson's trichrome stain for his- topathological analysis. The hydroxyproline (HYP) content in lung tissues was detected using an enzyme-linked im- munosorbent assay (ELISA) kit. The expression of transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) in lung tissues was detected by immunohistochemical staining and Western blotting. Results: A mice model of PQ-induced pulmonary fibrosis was established. Histological examination of lung tissues showed that PAPA treatment moderated the pathological changes of pulmonary fibrosis, including alveolar collapse and interstitial collagen depo- sition. HYP content in lung tissues increased soon after PQ intoxication but had decreased significantly by the 28th day after PAPA treatment. Immunohistochemical staining and Western blotting showed that PAPA treatment significantly down-regulated the enhanced levels of TGF-β1 and e-SMA in lung tissues caused by PQ exposure. However, PAPA treatment alone could not significantly ameliorate the lower survival rate and weight loss of treated mice. MP treatment enhanced the survival rate, but had no significant effects on attenuating PQ-induced pulmonary fibrosis or reducing the expression of TGF-β1 and a-SMA. Conclusions: This study demonstrates that PAPA treatment effectively suppresses PQ-induced alveolar collapse and collagen deposition in lung tissues through reducing the expression of TGF-β1 and a-SMA. Thus, RAPA has potential value in the treatment of PQ-induced pulmonary fibrosis.