[Objective] The paper aimed to discuss effects of different concentrations of lead stress on Alternanthera philoxeroides growth and physiological indices,to explore phytoremediation methods for removal of lead polluti...[Objective] The paper aimed to discuss effects of different concentrations of lead stress on Alternanthera philoxeroides growth and physiological indices,to explore phytoremediation methods for removal of lead pollution. [Method] A. philoxeroides in water culture was treated with different concentration of lead,and then,its external injury was observed,its growth and physiological indexes were measured. [Result] A. philoxeroides biomass and chlorophyll content decreased; conductivity and malonaldehyde (MDA ) content were increased; the SOD,POD and CAT activities showed a trend of first increase and then decrease with increase in concentration of lead stress. [Conclusion] With increase in lead concentration,the cell membrane permeability increased and MDA had a higher accumulation,antioxidant enzymes activity decreased,the normal oxidative metabolism of A. philoxeroides was severely affected,leading it to wilt.展开更多
Salicylic acid (SA) was an essential component of the plant resistance to pathogens and also plays an important role in mediating plant response to some abiotic stress. The possible effects of SA on the growth and H...Salicylic acid (SA) was an essential component of the plant resistance to pathogens and also plays an important role in mediating plant response to some abiotic stress. The possible effects of SA on the growth and H2O2-metabolizing enzymes in rice seedlings under lead stress were studied. When rice seedlings grown in nutrient solution containing Pb^2+ (0, 0.05, 0.15, 0.25 mmol/L) for 18 d, the plant biomass as well as the chlorophyll content of leaves decreased with increasing Pb concentration. The pre-treatment with SA (treated with 0.1 mmol/L SA for 48 h before Pb stress) partially protected seedlings from Pb toxicity. The chlorophyll contents were significant higher in leaves of Pb-exposed with SA pre-treatment seedlings than in Pb-exposed plants at the same Pb intensity. SA pre-treated alone could significantly increase the length of shoot and root of seedlings but the vigour difference was not marked under long-term exposure to Pb toxicity. SA pre-treated influence the H2O2 level in leaves of seedlings by up-regulating the activity of superoxide dismutase (SOD), repressing the activity of catalase (CAT) and ascorbate peroxidase (APX) depending on the concentrations of Pb^2+ in the growth medium. The results supported the conclusion that SA played a positive role in rice seedlings against Pb toxicity.展开更多
[Objectives]This study was conducted to discuss the Pb-enrichment ability of Iris pseudacorus,and reveal the effects of different concentrations of Pb stress on the physiological metabolism of I.pseudacorus.[Methods]I...[Objectives]This study was conducted to discuss the Pb-enrichment ability of Iris pseudacorus,and reveal the effects of different concentrations of Pb stress on the physiological metabolism of I.pseudacorus.[Methods]I.pseudacorus L.as a test material was cultured by the nutrient solution culture method and analyzed for malondialdehyde(MDA),glutathione(GSH),cysteine(Cys)and proline(Pro)contents of plant leaves as well as catalase(CAT)and superoxide dismutase(SOD)activity under different concentrations of Pb stress(0,200,400,600,800,1000,1200 mg/L).[Results]With the increase of Pb concentration,the Pb content of leaves and roots gradually increased,and the order of increase was root>leaf.Roots and leaves reached maximums at the high concentration of 1200 mg/L Pb,and their contents were 9034.6 and 11.2 mg/kg,respectively.Under Pb stress,the contents of GSH,Cys and Pro,and the activity of CAT and SOD in I.pseudacorus showed a trend of first increasing and then decreasing with the increase of Pb concentration,and each index reached a maximum under the treatment of 400 mg/L.The level of MDA in the leaves of I.pseudacorus rose significantly under Pb stress,indicating that Pb stress caused the cell membrane of I.pseudacorus to be damaged by peroxidation.[Conclusions]This study provides a theoretical basis for further research and use of this plant for metal pollution remediation in the future.展开更多
Heavy metals have been found to be endocrine disruptors in invertebrates.Lead is one of the most widespread elements of contamination,but there has been no research about the effects of lead stress on vitellogenin(Vg)...Heavy metals have been found to be endocrine disruptors in invertebrates.Lead is one of the most widespread elements of contamination,but there has been no research about the effects of lead stress on vitellogenin(Vg) gene expression in insects exposed to lead over multiple generations.In this paper,the effects of different concentrations of lead(0,0.3,4.8 and 76.8 mg kg^(–1)) on the expression of Vg in the beet armyworm over five successive generations were studied.The results showed that lead stress had significant effects on Vg expression in a dose-dependent manner.For females at the larval and adult stages,as lead concentration increased,Vg expression was significantly inhibited; for males at these two developmental stages,Vg expression was induced and increased as lead concentration increased.In addition,with the increase over stressed generations,inhibited effects for females and induced effects for males at the larval and adult stages became increasingly more obvious.However,at the pupal stage,Vg expression in the two genders was different from that at the larval and adult stages.The results indicate that lead stress can upregulate Vg expression in males which should be a useful indicator for environmental risk assessment.展开更多
Lead (Pb) is an environmental pollutant extremely toxic to plants and other living organisms including humans. In order to research the relieve effect of Bacillus subtilis QM3 on wheat roots (Triticum aestivum L.), af...Lead (Pb) is an environmental pollutant extremely toxic to plants and other living organisms including humans. In order to research the relieve effect of Bacillus subtilis QM3 on wheat roots (Triticum aestivum L.), after wheat seeds germination for two days, wheat root caused, the experimental materials were divided into four large groups and each large group was placed in 6 petri dishes as six small groups, and then four large groups respectively cultivated with sterile water (CK), 108 CFU/ml B. subtilis QM3 (B1), 107 CFU/ml B. subtilis QM3 (B2) and 106 CFU/ml B. subtilis QM3 (B3) for 2 days, after that stressed with lead nitrate, Pb (NO)2, Pb2+ concentration calculation at five concentrations (50, 250, 500, 1000, 2000 mg/L), sterile water and different Pb2+ concentration liquid respectively cultivated the 6 small groups in each large group measuring root morpholog and assaying changes of antioxidant enzyme activity. The results showed that: with the increase of the Pb2+ concentration, root morphology index and the activity of antioxidant enzyme increased first and then decreased. Root morphology index reached the maximum in 50 mg/L Pb2+ concentration. B. subtilis QM3 clearly promoted the growth of the root and the antioxidant enzyme activity (p 0.05). Without Pb stress, B. subtilis QM3 had the best improving effect on root morphology. When Pb2+ concentration was 50 mg/L, superoxide dismutase (SOD) and ascorbate peroxidase (APX) reached the maximum. SOD activity, compared with CK, B1, B2 and B3 respectively, increased by 8.05%, 27.41% and 9.79%. APX activity, compared with CK, B1, B2 and B3 respectively, increased by 52.70%, 111.15% and 14.16%. Catalase (CAT) and peroxidase (POD) reached the maximum at the Pb2+ concentration was 500 mg/L. CAT activity, compared with CK, B1, B2 and B3 respectively, increased by 59.93%, 83.46% and 70.59%. POD activity, compared with CK, B1, B2 and B3 respectively, increased by 2.88%, 10.11% and 7.67%. Result suggested that B. subtilis QM3 could improve root growth and antioxidant enzyme activity of the wheat root under lead stress.展开更多
Objective To evaluate the effect of oral administration of Kombucha tea (K-tea) on lead induced oxidative stress. Methods Sprague Dawley rats were administered 1 mL of 3.8% lead acetate solution daily alone or in comb...Objective To evaluate the effect of oral administration of Kombucha tea (K-tea) on lead induced oxidative stress. Methods Sprague Dawley rats were administered 1 mL of 3.8% lead acetate solution daily alone or in combination with K-tea orally for 45 d, and the antioxidant status and lipid peroxidation were evaluated. Results Oral administration of lead acetate to rats enhanced lipid peroxidation and release of creatine phosphokinase and decreased levels of reduced glutathione (GSH) and antioxidant enzymes (superoxide dismutase, SOD and glutathione peroxidase, GPx). Lead treatment did not alter humoral immunity, but inhibited DTH response when compared to the control. Lead administration also increased DNA fragmentation in liver. Oral administration of Kombucha tea to rats exposed to lead decreased lipid peroxidation and DNA damage with a concomitant increase in the reduced glutathione level and GPx activity. Kombucha tea supplementation relieved the lead induced immunosuppression to appreciable levels. Conclusion The results suggest that K-tea has potent antioxidant and immunomodulating properties.展开更多
We aimed to investigate the short-term correlation between blood lead levels and oxidative stress generation in coal miners. The study involved 94 male coal miners from the Velenje Coal mine, arranged into four groups...We aimed to investigate the short-term correlation between blood lead levels and oxidative stress generation in coal miners. The study involved 94 male coal miners from the Velenje Coal mine, arranged into four groups: three groups according to the number of consecutive working days, and a fourth control group. Miners who worked for three consecutive days had higher blood levels of lead and 8-isoprostane than the control group(P 〈 0.001). Correlation between lead and 8-isoprostane was of medium strength(r = 0.512, P 〈 0.001). Short-term lead environmental exposure can potentially harmful and should be considered when formulating improvements in working processes.展开更多
[ Objective] To investigate the effects of Newcastle disease vaccination and lead exposure on growth and development of egg yellow feather quail. [ Method] Ninety 14-day-old quails were assigned randomly to 10 groups ...[ Objective] To investigate the effects of Newcastle disease vaccination and lead exposure on growth and development of egg yellow feather quail. [ Method] Ninety 14-day-old quails were assigned randomly to 10 groups ( n = 9), and they fed and drunk at liberty. A 2 ×5 factorial design was used. The quail immunized with ND vaccine and those non-immunized were exposed to lead at a dosage of 0, 50,500, 1 000 and 2 000 mg/L, respectively. [Result] The ND immunization reduced body weight significantly ( P 〈 0.01 ) and increased liver index and serum levels of hy- aluronic acid in quail within 1 -2 weeks post inoculation. The quail exposed to 2 000 mg/L lead acetate had significantly lower body weight than the control ( P 〈 0.01 ). From 7 weeks old, the same inhibitory effect was observed in the quail'exposed to lead at different dosages ( P 〈 0.01 ). In addition, the lead poisoning could cause decreased feed intake, depilation, gonadal dysgenesis, and increased serum levels of hyaluronic acid. [ Conduslon] The inhibitory effect of ND vaccination on growth of quail occurs within 1 -2 weeks post inoculation; thus, the effects of immune stress should not be worried in quail production. The lead poisoning has significant effects on body weight and feed intake of quail, and lead dosage and duration affect the inhibitory effects of lead. Gonadal dysgenesis is an important indicator of lead poisoning in. quail. The serum levels of hyaluronic acid can be used to determine whether the quail have been immunized with ND vaccine or have contacted lead pollutants.展开更多
Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite elemen...Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite element method, the cause for peeling damage of Cu-Fe-P lead frame aUoy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress coacentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of intefrace make it easy to develop the crack and peeling damage on finish rolling. The larger Fe particles in the Cu-Fe-P alloy should be avoided.展开更多
After intraperitoneal injection of 20 mg/kg lead acetate, rats received 8 weeks of treadmill exercise (15-22 m/min, 25-64 minutes) and/or treadmill exercise at 1.6 km/h until exhaustion. The markers related to neuro...After intraperitoneal injection of 20 mg/kg lead acetate, rats received 8 weeks of treadmill exercise (15-22 m/min, 25-64 minutes) and/or treadmill exercise at 1.6 km/h until exhaustion. The markers related to neurotoxicity were measured by enzyme-linked immunosorbent assay method. 8 weeks of treadmill exercise significantly increased brain-derived neurotrophic factor level in the hippocampus (P = 0.04) and plasma level of total antioxidant capacity of rats exposed to lead acetate (P 〈 0.001), and significantly decreased plasma level of malondialdehyde (P 〈 0.001). Acute exercise only decreased the hippocampal malondialdehyde level (P = 0.09) and increased brain-derived neurotrophic factor level in the hippocampus (P = 0.66). Acute exercise also enhanced the total antioxidant capacity in rats exposed to lead acetate, insignificantly (P = 0.99), These findings suggest that chronic treadmill exercise can significantly decrease neurotoxicity and alleviate oxidative stress in rats exposed to lead acetate. However, acute endurance exercise was not associated with these beneficial effects.展开更多
Objectives: The aim of this study was to verify mitigating effects of the antioxidants α tocopherol (Vitamin E) and ascorbic acid (Vitamin C) on lead induced renal toxicity in adult male Wistar rats. Methods: A total...Objectives: The aim of this study was to verify mitigating effects of the antioxidants α tocopherol (Vitamin E) and ascorbic acid (Vitamin C) on lead induced renal toxicity in adult male Wistar rats. Methods: A total of 36 mature male Wistar rats separated into 1 control group fed with rat feeds and water only and 3 study groups fed with 10 mg/ml of lead acetate, 10 mg/ml of lead acetate + 200 mg/2ml of vitamin C and 10 mg/ml of lead acetate + 100 mg/2ml of vitamin E respectively in addition to feds and water for 28 days were used. Blood samples were obtained for renal indices and the kidneys of all rats were harvested, weighed and prepared for histological examination. Result: The percentage weight gain was highest among control rats (20.70%), followed by lead + vitamin E group (18.42%), lead + vitamin C group (17.00%) and the least amongst the lead group (9.50%). The mean serum uric acid of 419.20 ± 35.80 μmol/L in the lead treatment group was significantly higher than 395.50 ± 15.35 μmol/L, 393.30 ± 14.16 μmol/L and 387.67 ± 14.56 μmol/L in the lead + vitamin C group, lead + vitamin E group and controls respectively. The extent and proportion of renal tissue damage was higher in the lead-treated group and the commonest renal abnormalities observed were tubular and interstitial damage seen in 90.00% of rats in the lead-treated group compared to 75.00% and 60.00% in the lead + vitamin C and the lead + vitamin E groups respectively while the control rats had a normal histological appearance. Conclusions: The sub-acute administration of lead acetate may have inhibitory effect on growth of animals, and adversely affect renal function and histology with uric acid as a more reliable marker of lead induced renal toxicity compared to urea and creatinine. The histologic parameters of tubulointerstitial abnormalities were also consistent with lead toxicity. Antioxidants were useful in reducing lead induced renal damage and growth inhibition with vitamin E producing a more potent effect compared to Vitamin C.展开更多
基金Supported by National Natural Science Foundation of China(31060031)Youth Foundation of Yunnan University of Nationalities(09QN02)~~
文摘[Objective] The paper aimed to discuss effects of different concentrations of lead stress on Alternanthera philoxeroides growth and physiological indices,to explore phytoremediation methods for removal of lead pollution. [Method] A. philoxeroides in water culture was treated with different concentration of lead,and then,its external injury was observed,its growth and physiological indexes were measured. [Result] A. philoxeroides biomass and chlorophyll content decreased; conductivity and malonaldehyde (MDA ) content were increased; the SOD,POD and CAT activities showed a trend of first increase and then decrease with increase in concentration of lead stress. [Conclusion] With increase in lead concentration,the cell membrane permeability increased and MDA had a higher accumulation,antioxidant enzymes activity decreased,the normal oxidative metabolism of A. philoxeroides was severely affected,leading it to wilt.
基金Project supported by the National Key Basic Research and Development Program (No. 2002CB410804) the National Natural Science Foundation of China (No. 30671255).
文摘Salicylic acid (SA) was an essential component of the plant resistance to pathogens and also plays an important role in mediating plant response to some abiotic stress. The possible effects of SA on the growth and H2O2-metabolizing enzymes in rice seedlings under lead stress were studied. When rice seedlings grown in nutrient solution containing Pb^2+ (0, 0.05, 0.15, 0.25 mmol/L) for 18 d, the plant biomass as well as the chlorophyll content of leaves decreased with increasing Pb concentration. The pre-treatment with SA (treated with 0.1 mmol/L SA for 48 h before Pb stress) partially protected seedlings from Pb toxicity. The chlorophyll contents were significant higher in leaves of Pb-exposed with SA pre-treatment seedlings than in Pb-exposed plants at the same Pb intensity. SA pre-treated alone could significantly increase the length of shoot and root of seedlings but the vigour difference was not marked under long-term exposure to Pb toxicity. SA pre-treated influence the H2O2 level in leaves of seedlings by up-regulating the activity of superoxide dismutase (SOD), repressing the activity of catalase (CAT) and ascorbate peroxidase (APX) depending on the concentrations of Pb^2+ in the growth medium. The results supported the conclusion that SA played a positive role in rice seedlings against Pb toxicity.
基金Key R&D Project of Shanxi Province(201903D221070)Applied Basic Research Project of Shanxi Academy of Agricultural Sciences(YBSJJ2017).
文摘[Objectives]This study was conducted to discuss the Pb-enrichment ability of Iris pseudacorus,and reveal the effects of different concentrations of Pb stress on the physiological metabolism of I.pseudacorus.[Methods]I.pseudacorus L.as a test material was cultured by the nutrient solution culture method and analyzed for malondialdehyde(MDA),glutathione(GSH),cysteine(Cys)and proline(Pro)contents of plant leaves as well as catalase(CAT)and superoxide dismutase(SOD)activity under different concentrations of Pb stress(0,200,400,600,800,1000,1200 mg/L).[Results]With the increase of Pb concentration,the Pb content of leaves and roots gradually increased,and the order of increase was root>leaf.Roots and leaves reached maximums at the high concentration of 1200 mg/L Pb,and their contents were 9034.6 and 11.2 mg/kg,respectively.Under Pb stress,the contents of GSH,Cys and Pro,and the activity of CAT and SOD in I.pseudacorus showed a trend of first increasing and then decreasing with the increase of Pb concentration,and each index reached a maximum under the treatment of 400 mg/L.The level of MDA in the leaves of I.pseudacorus rose significantly under Pb stress,indicating that Pb stress caused the cell membrane of I.pseudacorus to be damaged by peroxidation.[Conclusions]This study provides a theoretical basis for further research and use of this plant for metal pollution remediation in the future.
基金supported by the National Key Research and Development Program of China (2017YFD0201907)the National Science and Technology Major Project,China (2016ZX08012-004)the Key Research and Development Project of Jiangsu Province,China (BE2017379-3)
文摘Heavy metals have been found to be endocrine disruptors in invertebrates.Lead is one of the most widespread elements of contamination,but there has been no research about the effects of lead stress on vitellogenin(Vg) gene expression in insects exposed to lead over multiple generations.In this paper,the effects of different concentrations of lead(0,0.3,4.8 and 76.8 mg kg^(–1)) on the expression of Vg in the beet armyworm over five successive generations were studied.The results showed that lead stress had significant effects on Vg expression in a dose-dependent manner.For females at the larval and adult stages,as lead concentration increased,Vg expression was significantly inhibited; for males at these two developmental stages,Vg expression was induced and increased as lead concentration increased.In addition,with the increase over stressed generations,inhibited effects for females and induced effects for males at the larval and adult stages became increasingly more obvious.However,at the pupal stage,Vg expression in the two genders was different from that at the larval and adult stages.The results indicate that lead stress can upregulate Vg expression in males which should be a useful indicator for environmental risk assessment.
文摘Lead (Pb) is an environmental pollutant extremely toxic to plants and other living organisms including humans. In order to research the relieve effect of Bacillus subtilis QM3 on wheat roots (Triticum aestivum L.), after wheat seeds germination for two days, wheat root caused, the experimental materials were divided into four large groups and each large group was placed in 6 petri dishes as six small groups, and then four large groups respectively cultivated with sterile water (CK), 108 CFU/ml B. subtilis QM3 (B1), 107 CFU/ml B. subtilis QM3 (B2) and 106 CFU/ml B. subtilis QM3 (B3) for 2 days, after that stressed with lead nitrate, Pb (NO)2, Pb2+ concentration calculation at five concentrations (50, 250, 500, 1000, 2000 mg/L), sterile water and different Pb2+ concentration liquid respectively cultivated the 6 small groups in each large group measuring root morpholog and assaying changes of antioxidant enzyme activity. The results showed that: with the increase of the Pb2+ concentration, root morphology index and the activity of antioxidant enzyme increased first and then decreased. Root morphology index reached the maximum in 50 mg/L Pb2+ concentration. B. subtilis QM3 clearly promoted the growth of the root and the antioxidant enzyme activity (p 0.05). Without Pb stress, B. subtilis QM3 had the best improving effect on root morphology. When Pb2+ concentration was 50 mg/L, superoxide dismutase (SOD) and ascorbate peroxidase (APX) reached the maximum. SOD activity, compared with CK, B1, B2 and B3 respectively, increased by 8.05%, 27.41% and 9.79%. APX activity, compared with CK, B1, B2 and B3 respectively, increased by 52.70%, 111.15% and 14.16%. Catalase (CAT) and peroxidase (POD) reached the maximum at the Pb2+ concentration was 500 mg/L. CAT activity, compared with CK, B1, B2 and B3 respectively, increased by 59.93%, 83.46% and 70.59%. POD activity, compared with CK, B1, B2 and B3 respectively, increased by 2.88%, 10.11% and 7.67%. Result suggested that B. subtilis QM3 could improve root growth and antioxidant enzyme activity of the wheat root under lead stress.
文摘Objective To evaluate the effect of oral administration of Kombucha tea (K-tea) on lead induced oxidative stress. Methods Sprague Dawley rats were administered 1 mL of 3.8% lead acetate solution daily alone or in combination with K-tea orally for 45 d, and the antioxidant status and lipid peroxidation were evaluated. Results Oral administration of lead acetate to rats enhanced lipid peroxidation and release of creatine phosphokinase and decreased levels of reduced glutathione (GSH) and antioxidant enzymes (superoxide dismutase, SOD and glutathione peroxidase, GPx). Lead treatment did not alter humoral immunity, but inhibited DTH response when compared to the control. Lead administration also increased DNA fragmentation in liver. Oral administration of Kombucha tea to rats exposed to lead decreased lipid peroxidation and DNA damage with a concomitant increase in the reduced glutathione level and GPx activity. Kombucha tea supplementation relieved the lead induced immunosuppression to appreciable levels. Conclusion The results suggest that K-tea has potent antioxidant and immunomodulating properties.
文摘We aimed to investigate the short-term correlation between blood lead levels and oxidative stress generation in coal miners. The study involved 94 male coal miners from the Velenje Coal mine, arranged into four groups: three groups according to the number of consecutive working days, and a fourth control group. Miners who worked for three consecutive days had higher blood levels of lead and 8-isoprostane than the control group(P 〈 0.001). Correlation between lead and 8-isoprostane was of medium strength(r = 0.512, P 〈 0.001). Short-term lead environmental exposure can potentially harmful and should be considered when formulating improvements in working processes.
基金funded by the Key Scientific and Technological Project of Henan Province ( 082102130002)
文摘[ Objective] To investigate the effects of Newcastle disease vaccination and lead exposure on growth and development of egg yellow feather quail. [ Method] Ninety 14-day-old quails were assigned randomly to 10 groups ( n = 9), and they fed and drunk at liberty. A 2 ×5 factorial design was used. The quail immunized with ND vaccine and those non-immunized were exposed to lead at a dosage of 0, 50,500, 1 000 and 2 000 mg/L, respectively. [Result] The ND immunization reduced body weight significantly ( P 〈 0.01 ) and increased liver index and serum levels of hy- aluronic acid in quail within 1 -2 weeks post inoculation. The quail exposed to 2 000 mg/L lead acetate had significantly lower body weight than the control ( P 〈 0.01 ). From 7 weeks old, the same inhibitory effect was observed in the quail'exposed to lead at different dosages ( P 〈 0.01 ). In addition, the lead poisoning could cause decreased feed intake, depilation, gonadal dysgenesis, and increased serum levels of hyaluronic acid. [ Conduslon] The inhibitory effect of ND vaccination on growth of quail occurs within 1 -2 weeks post inoculation; thus, the effects of immune stress should not be worried in quail production. The lead poisoning has significant effects on body weight and feed intake of quail, and lead dosage and duration affect the inhibitory effects of lead. Gonadal dysgenesis is an important indicator of lead poisoning in. quail. The serum levels of hyaluronic acid can be used to determine whether the quail have been immunized with ND vaccine or have contacted lead pollutants.
基金Funded by the National "863" Plan of China ( No.2002AA331112) ,the Doctorate Foundation of Northwestern Poly-technical University,andthe Science Research Foundation of HenanUniversity of Science and Technology(No.2006ZY041)
文摘Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite element method, the cause for peeling damage of Cu-Fe-P lead frame aUoy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress coacentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of intefrace make it easy to develop the crack and peeling damage on finish rolling. The larger Fe particles in the Cu-Fe-P alloy should be avoided.
文摘After intraperitoneal injection of 20 mg/kg lead acetate, rats received 8 weeks of treadmill exercise (15-22 m/min, 25-64 minutes) and/or treadmill exercise at 1.6 km/h until exhaustion. The markers related to neurotoxicity were measured by enzyme-linked immunosorbent assay method. 8 weeks of treadmill exercise significantly increased brain-derived neurotrophic factor level in the hippocampus (P = 0.04) and plasma level of total antioxidant capacity of rats exposed to lead acetate (P 〈 0.001), and significantly decreased plasma level of malondialdehyde (P 〈 0.001). Acute exercise only decreased the hippocampal malondialdehyde level (P = 0.09) and increased brain-derived neurotrophic factor level in the hippocampus (P = 0.66). Acute exercise also enhanced the total antioxidant capacity in rats exposed to lead acetate, insignificantly (P = 0.99), These findings suggest that chronic treadmill exercise can significantly decrease neurotoxicity and alleviate oxidative stress in rats exposed to lead acetate. However, acute endurance exercise was not associated with these beneficial effects.
文摘Objectives: The aim of this study was to verify mitigating effects of the antioxidants α tocopherol (Vitamin E) and ascorbic acid (Vitamin C) on lead induced renal toxicity in adult male Wistar rats. Methods: A total of 36 mature male Wistar rats separated into 1 control group fed with rat feeds and water only and 3 study groups fed with 10 mg/ml of lead acetate, 10 mg/ml of lead acetate + 200 mg/2ml of vitamin C and 10 mg/ml of lead acetate + 100 mg/2ml of vitamin E respectively in addition to feds and water for 28 days were used. Blood samples were obtained for renal indices and the kidneys of all rats were harvested, weighed and prepared for histological examination. Result: The percentage weight gain was highest among control rats (20.70%), followed by lead + vitamin E group (18.42%), lead + vitamin C group (17.00%) and the least amongst the lead group (9.50%). The mean serum uric acid of 419.20 ± 35.80 μmol/L in the lead treatment group was significantly higher than 395.50 ± 15.35 μmol/L, 393.30 ± 14.16 μmol/L and 387.67 ± 14.56 μmol/L in the lead + vitamin C group, lead + vitamin E group and controls respectively. The extent and proportion of renal tissue damage was higher in the lead-treated group and the commonest renal abnormalities observed were tubular and interstitial damage seen in 90.00% of rats in the lead-treated group compared to 75.00% and 60.00% in the lead + vitamin C and the lead + vitamin E groups respectively while the control rats had a normal histological appearance. Conclusions: The sub-acute administration of lead acetate may have inhibitory effect on growth of animals, and adversely affect renal function and histology with uric acid as a more reliable marker of lead induced renal toxicity compared to urea and creatinine. The histologic parameters of tubulointerstitial abnormalities were also consistent with lead toxicity. Antioxidants were useful in reducing lead induced renal damage and growth inhibition with vitamin E producing a more potent effect compared to Vitamin C.