AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human...AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.展开更多
A new temperature-resistant and salt-tolerant mixed surfactant system(referred to as the SS system)for enhancing oil recovery at the Tahe Oilfield(Xinjiang,China)was evaluated.Based on the analysis of the crude oil,th...A new temperature-resistant and salt-tolerant mixed surfactant system(referred to as the SS system)for enhancing oil recovery at the Tahe Oilfield(Xinjiang,China)was evaluated.Based on the analysis of the crude oil,the formation water and rock components in the Tahe Oilfield,the long-term thermal stability,salt tolerance and the ability to change the wettability,interfacial activity and oil washing efficiency of the mixed surfactant system were studied.The system contains the anionic surfactant SDB and another cationic surfactant SDY.When the total mass concentration of the SS solution is 0.15 wt%,m(SDB)/m(SDY)ratio is 1 to 1,and excellent efficiencies are achieved for oil washing for five kinds of Tahe Oilfield crude oils(more than 60%).In addition,after adding cationic surfactant,the adsorption capacity of the surfactant is further reduced,reaching 0.261 mg/g.The oil displacement experiments indicate that under a temperature of 150°C and a salinity of 24.6×104 mg/L,the SS system enhances the oil recovery by over 10%after water flooding.The SS anionic–cationic surfactant system is first presented in the open literature that can be successfully applied to obtain predictions of Tahe Oilfield carbonate reservoirs with a high temperature and high salinity.展开更多
[目的]分离筛选吡啶高效降解菌,降低吡啶废水生化处理成本。[方法]从生化池活性污泥中分离筛选能以吡啶为唯一碳源的高效降解菌,通过生理生化、形态特征、16S r DNA鉴定及序列分析确定菌株特性和种属。进行混菌组合及固定化试验,筛选最...[目的]分离筛选吡啶高效降解菌,降低吡啶废水生化处理成本。[方法]从生化池活性污泥中分离筛选能以吡啶为唯一碳源的高效降解菌,通过生理生化、形态特征、16S r DNA鉴定及序列分析确定菌株特性和种属。进行混菌组合及固定化试验,筛选最佳固定化材料。[结果]筛选出2株吡啶高效降解菌,分别命名为BD1、BD2,鉴定为克雷伯氏菌。[结论]在吡啶质量浓度100 mg/L条件下,BD1与BD2菌液配比为2∶1(P7)对吡啶的降解率达到了100%。正交试验确定P7降解吡啶的最佳环境条件组合为吡啶质量浓度150 mg/L、盐浓度1%、pH值7.0、温度30℃,组合纤维生物填料对混合菌P7的挂膜效果最好,能提高菌株对吡啶的降解效率及其稳定性。展开更多
Background: Experimental manipulations of tree diversity have often found overyielding in mixed-species plantations. While most experiments are still in the early stages of stand development, the impacts of tree diver...Background: Experimental manipulations of tree diversity have often found overyielding in mixed-species plantations. While most experiments are still in the early stages of stand development, the impacts of tree diversity are expected to accumulate over time. Here, I present findings from a 31-year-old tree diversity experiment(as of2018) in Japan.Results: I find that the net diversity effect on stand biomass increased linearly through time. The species mixture achieved 64% greater biomass than the average monoculture biomass 31 years after planting. The complementarity effect was positive and increased exponentially with time. The selection effect was negative and decreased exponentially with time. In the early stages(≤ 3 years), the positive complementarity effect was explained by enhanced growths of early-and mid-successional species in the mixture. Later on(≥ 15 years), it was explained by their increased survival rates owing to vertical spatial partitioning — i.e. alleviation of self-thinning via canopy stratification. The negative selection effect resulted from suppressed growths of late-successional species in the bottom layer.Conclusions: The experiment provides pioneering evidence that the positive impacts of diversity-driven spatial partitioning on forest biomass can accumulate over multiple decades. The results indicate that forest biomass production and carbon sequestration can be enhanced by multispecies afforestation strategies.展开更多
Background No studies have examined endogenous insulin secretion in pediatric patients with type 1 diabetes in China using the gold-standard mixed-meal tolerance test.Because the latter is labor-intensive,we examined ...Background No studies have examined endogenous insulin secretion in pediatric patients with type 1 diabetes in China using the gold-standard mixed-meal tolerance test.Because the latter is labor-intensive,we examined simpler surrogate markers of endogenous insulin secretion in Chinese youth,as previously reported for a European population.Methods Participants were 57 children and adolescents with type 1 diabetes aged 4.4-16.8 years(56% females).We per-formed 120-minute mixed-meal tolerance tests with serum C-peptide(CP)measurements every 30 minutes.Severe insulin deficiency(SID)was defined as CP peak<0.2 nmol/L.Urine CP and creatinine levels were measured at 0 and 120 minutes.Results Twenty-five(44%)patients had SID.Fasting CP levels missed one case(96% sensitivity)with no false posi-tives(100% specificity).While the 120-minute urine CP/creatinine had 100% sensitivity,it yielded markedly lower speci-ficity(63%).Every 1-year increase in diabetes duration and 1-year decrease in age at diagnosis were associated with 37%(P<0.001)and 20%(P=0.005)reductions in serum CP area-under-the-curve,respectively.Thus,86% of children aged<5 years had SID compared to none among patients aged ≥11 years.Conclusions Simple fasting CP measurements could be used to detect most SID cases in Chinese youth with type 1 diabe-tes.Fasting CP is a far more reliable measure of endogenous insulin secretion than the more commonly used insulin dose.Therefore,it could more precisely determine insulin secretory capacity to target those who could benefit,if treatments to preserve residual insulin secretion are developed.展开更多
文摘AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.
基金The support from the China National High Technology Research and Development Program(No.2013AA064301)the National Natural Science Foundation of China(51274210)the Research Start-up Fund of Karamay Campus of China University of Petroleum-Beijing(XQZX20200013)is greatly appreciated.
文摘A new temperature-resistant and salt-tolerant mixed surfactant system(referred to as the SS system)for enhancing oil recovery at the Tahe Oilfield(Xinjiang,China)was evaluated.Based on the analysis of the crude oil,the formation water and rock components in the Tahe Oilfield,the long-term thermal stability,salt tolerance and the ability to change the wettability,interfacial activity and oil washing efficiency of the mixed surfactant system were studied.The system contains the anionic surfactant SDB and another cationic surfactant SDY.When the total mass concentration of the SS solution is 0.15 wt%,m(SDB)/m(SDY)ratio is 1 to 1,and excellent efficiencies are achieved for oil washing for five kinds of Tahe Oilfield crude oils(more than 60%).In addition,after adding cationic surfactant,the adsorption capacity of the surfactant is further reduced,reaching 0.261 mg/g.The oil displacement experiments indicate that under a temperature of 150°C and a salinity of 24.6×104 mg/L,the SS system enhances the oil recovery by over 10%after water flooding.The SS anionic–cationic surfactant system is first presented in the open literature that can be successfully applied to obtain predictions of Tahe Oilfield carbonate reservoirs with a high temperature and high salinity.
文摘[目的]分离筛选吡啶高效降解菌,降低吡啶废水生化处理成本。[方法]从生化池活性污泥中分离筛选能以吡啶为唯一碳源的高效降解菌,通过生理生化、形态特征、16S r DNA鉴定及序列分析确定菌株特性和种属。进行混菌组合及固定化试验,筛选最佳固定化材料。[结果]筛选出2株吡啶高效降解菌,分别命名为BD1、BD2,鉴定为克雷伯氏菌。[结论]在吡啶质量浓度100 mg/L条件下,BD1与BD2菌液配比为2∶1(P7)对吡啶的降解率达到了100%。正交试验确定P7降解吡啶的最佳环境条件组合为吡啶质量浓度150 mg/L、盐浓度1%、pH值7.0、温度30℃,组合纤维生物填料对混合菌P7的挂膜效果最好,能提高菌株对吡啶的降解效率及其稳定性。
基金a Grant-in-Aid for Young Scientists B (No. 16 K18715)a JSPS Overseas Research Fellowship (No. 201860500) from the Japan Society for the Promotion of Science。
文摘Background: Experimental manipulations of tree diversity have often found overyielding in mixed-species plantations. While most experiments are still in the early stages of stand development, the impacts of tree diversity are expected to accumulate over time. Here, I present findings from a 31-year-old tree diversity experiment(as of2018) in Japan.Results: I find that the net diversity effect on stand biomass increased linearly through time. The species mixture achieved 64% greater biomass than the average monoculture biomass 31 years after planting. The complementarity effect was positive and increased exponentially with time. The selection effect was negative and decreased exponentially with time. In the early stages(≤ 3 years), the positive complementarity effect was explained by enhanced growths of early-and mid-successional species in the mixture. Later on(≥ 15 years), it was explained by their increased survival rates owing to vertical spatial partitioning — i.e. alleviation of self-thinning via canopy stratification. The negative selection effect resulted from suppressed growths of late-successional species in the bottom layer.Conclusions: The experiment provides pioneering evidence that the positive impacts of diversity-driven spatial partitioning on forest biomass can accumulate over multiple decades. The results indicate that forest biomass production and carbon sequestration can be enhanced by multispecies afforestation strategies.
基金supported by National Key Research and Development Program of China(No.2016YFC1305301)National Natural Science Foundation of China(No.81570759)+1 种基金Research Fund of Zhejiang Major Medical and Health Science and Technology and National Ministry of Health(WKJ-ZJ-1804)supported by a travel fellowship from the New Zealand-China Non-Communicable Diseases Research Collaboration Center.
文摘Background No studies have examined endogenous insulin secretion in pediatric patients with type 1 diabetes in China using the gold-standard mixed-meal tolerance test.Because the latter is labor-intensive,we examined simpler surrogate markers of endogenous insulin secretion in Chinese youth,as previously reported for a European population.Methods Participants were 57 children and adolescents with type 1 diabetes aged 4.4-16.8 years(56% females).We per-formed 120-minute mixed-meal tolerance tests with serum C-peptide(CP)measurements every 30 minutes.Severe insulin deficiency(SID)was defined as CP peak<0.2 nmol/L.Urine CP and creatinine levels were measured at 0 and 120 minutes.Results Twenty-five(44%)patients had SID.Fasting CP levels missed one case(96% sensitivity)with no false posi-tives(100% specificity).While the 120-minute urine CP/creatinine had 100% sensitivity,it yielded markedly lower speci-ficity(63%).Every 1-year increase in diabetes duration and 1-year decrease in age at diagnosis were associated with 37%(P<0.001)and 20%(P=0.005)reductions in serum CP area-under-the-curve,respectively.Thus,86% of children aged<5 years had SID compared to none among patients aged ≥11 years.Conclusions Simple fasting CP measurements could be used to detect most SID cases in Chinese youth with type 1 diabe-tes.Fasting CP is a far more reliable measure of endogenous insulin secretion than the more commonly used insulin dose.Therefore,it could more precisely determine insulin secretory capacity to target those who could benefit,if treatments to preserve residual insulin secretion are developed.
