Lead has caused serious environmental pollution due to its toxicity, accumulation in food chains and persistence in nature. In this paper, removal of lead from aqueous solutions is investigated using a novel gel adsor...Lead has caused serious environmental pollution due to its toxicity, accumulation in food chains and persistence in nature. In this paper, removal of lead from aqueous solutions is investigated using a novel gel adsorbent synthesized from natural condensed tannin. The novel adsorbent performs in aqueous solutions as a weak base with valid basic groups of 1.2mmol·g-1 tannin gel particles and therefore results in the elevation of pH value of aqueous solutions. Even when initial pH is 3.6, final pH at equilibrium can climb up to 6.5 that is above the pH value for Pb(OH)2 precipitation formation and then lead can be removed from wastewater by this so-called surface precipitation. The adsorption isotherm can be expressed by the Langmuir equation and the maximum capacity for adsorption of Pb is up to 92 mg·g-1 (based on dry adsorbent) when initial pH value is 3.6. Hence, the adsorbent does offer favorable properties in lead removal with respect to its high adsorption capacity at low initial pH value, which is advantageous to lead removal from acidic wastewater. A model is put forward to describe the individual adsorption phenomenon of the tannin gel adsorbent.展开更多
Objective： We studied the effects of Wortmannin （WM） on the proliferation and apoptosis of leukemia cells, and explore the possible mechanisms. Methods： The human myeloid leukemia cell line K562 was treated with d...Objective： We studied the effects of Wortmannin （WM） on the proliferation and apoptosis of leukemia cells, and explore the possible mechanisms. Methods： The human myeloid leukemia cell line K562 was treated with different concentrations of WM, and then detected the activity of the cell proliferation by MTT assay, comet tail formation of cell DNA damage phenomenon by single cell gel electrophoresis, cell apoptosis byAnnexin V-FITC/PI double staining and the expression levels of total Akt, phoshorylated Akt, NF-KB and protein in K562 cell by Western blotting, RT-PCR test before and after WM. Results： WM inhibited cell proliferation of K562 in a concentration-dependent manner, with IC50 value for 24 h being 25 nmol/L. WM induced apoptosis of K562 cells in a concentration-dependent manner, and could induce the breakage of DNA strand of K562 cell. The rate of DNA tail and the tail length of experimental groups were significantly higher than that of control group. WM may inhibit the expression of phosphorylated Akt and NF-KB protein in a dose-dependent manner in both the protein and gene levels, but no significant effect on total Akt protein. Conclusion： WM inhibited cell proliferation and induced apoptosis in K562 and concentration-dependent manner. The possible mechanism may be involved in the regulation of survival signaling pathway, such as PI3K/Akt/NK-KB.展开更多
Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues.Because of their prominent role in the global carbon balance and their possible rol...Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues.Because of their prominent role in the global carbon balance and their possible role in carbon sequestration, soil microbes are very important organisms in relation to global climate changes. This review focuses mainly on the responses of soil microbes to climate changes and subsequent effects on soil carbon dynamics. An overview table regarding extracellular enzyme activities(EAA) with all relevant literature data summarizes the effects of different ecosystems under various experimental treatments on EAA. Increasing temperature, altered soil moisture regimes, and elevated carbon dioxide significantly affect directly or indirectly soil microbial activities.High temperature regimes can increase the microbial activities which can provide positive feedback to climate change, whereas lower moisture condition in pedosystem can negate the increase, although the interactive effects still remain unanswered. Shifts in soil microbial community in response to climate change have been determined by gene probing, phospholipid fatty acid analysis(PLFA),terminal restriction length polymorphism(TRFLP), and denaturing gradient gel electrophoresis(DGGE), but in a recent investigations,omic technological interventions have enabled determination of the shift in soil microbe community at a taxa level, which can provide very important inputs for modeling C sequestration process. The intricacy and diversity of the soil microbial population and how it responds to climate change are big challenges, but new molecular and stable isotope probing tools are being developed for linking fluctuations in microbial diversity to ecosystem function.展开更多
The present paper develops the scaling theory of polyelectrolyte nanogels in dilute and semidilute solutions. The dependencies of the nanogel dimension on branching topology, charge fraction, subchain length, segment ...The present paper develops the scaling theory of polyelectrolyte nanogels in dilute and semidilute solutions. The dependencies of the nanogel dimension on branching topology, charge fraction, subchain length, segment number, solution concentration are obtained. For a single polyeleetrolyte nanogel in salt free solution, the nanogel may be swelled by the Coulombie repulsion （the so-called polyelectrolyte regime） or the osmotic eounterion pressure （the so-called osmotic regime）. Characteristics and boundaries between different regimes of a single polyelectrolyte nanogel are summarized. In dilute solution, the nanogels in polyeleetrolyte regime will distribute orderly with the increase of concentration. While the nanogels in osmotic regime will always distribute randomly. Different concentration dependencies of the size of a nanogel in polyeleetrolyte regime and in osmotic regime are also explored.展开更多
文摘Lead has caused serious environmental pollution due to its toxicity, accumulation in food chains and persistence in nature. In this paper, removal of lead from aqueous solutions is investigated using a novel gel adsorbent synthesized from natural condensed tannin. The novel adsorbent performs in aqueous solutions as a weak base with valid basic groups of 1.2mmol·g-1 tannin gel particles and therefore results in the elevation of pH value of aqueous solutions. Even when initial pH is 3.6, final pH at equilibrium can climb up to 6.5 that is above the pH value for Pb(OH)2 precipitation formation and then lead can be removed from wastewater by this so-called surface precipitation. The adsorption isotherm can be expressed by the Langmuir equation and the maximum capacity for adsorption of Pb is up to 92 mg·g-1 (based on dry adsorbent) when initial pH value is 3.6. Hence, the adsorbent does offer favorable properties in lead removal with respect to its high adsorption capacity at low initial pH value, which is advantageous to lead removal from acidic wastewater. A model is put forward to describe the individual adsorption phenomenon of the tannin gel adsorbent.
基金Supported by a grant from the Hubei Province Natural Science Foundation of China(No. 200511008)
文摘Objective： We studied the effects of Wortmannin （WM） on the proliferation and apoptosis of leukemia cells, and explore the possible mechanisms. Methods： The human myeloid leukemia cell line K562 was treated with different concentrations of WM, and then detected the activity of the cell proliferation by MTT assay, comet tail formation of cell DNA damage phenomenon by single cell gel electrophoresis, cell apoptosis byAnnexin V-FITC/PI double staining and the expression levels of total Akt, phoshorylated Akt, NF-KB and protein in K562 cell by Western blotting, RT-PCR test before and after WM. Results： WM inhibited cell proliferation of K562 in a concentration-dependent manner, with IC50 value for 24 h being 25 nmol/L. WM induced apoptosis of K562 cells in a concentration-dependent manner, and could induce the breakage of DNA strand of K562 cell. The rate of DNA tail and the tail length of experimental groups were significantly higher than that of control group. WM may inhibit the expression of phosphorylated Akt and NF-KB protein in a dose-dependent manner in both the protein and gene levels, but no significant effect on total Akt protein. Conclusion： WM inhibited cell proliferation and induced apoptosis in K562 and concentration-dependent manner. The possible mechanism may be involved in the regulation of survival signaling pathway, such as PI3K/Akt/NK-KB.
文摘Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues.Because of their prominent role in the global carbon balance and their possible role in carbon sequestration, soil microbes are very important organisms in relation to global climate changes. This review focuses mainly on the responses of soil microbes to climate changes and subsequent effects on soil carbon dynamics. An overview table regarding extracellular enzyme activities(EAA) with all relevant literature data summarizes the effects of different ecosystems under various experimental treatments on EAA. Increasing temperature, altered soil moisture regimes, and elevated carbon dioxide significantly affect directly or indirectly soil microbial activities.High temperature regimes can increase the microbial activities which can provide positive feedback to climate change, whereas lower moisture condition in pedosystem can negate the increase, although the interactive effects still remain unanswered. Shifts in soil microbial community in response to climate change have been determined by gene probing, phospholipid fatty acid analysis(PLFA),terminal restriction length polymorphism(TRFLP), and denaturing gradient gel electrophoresis(DGGE), but in a recent investigations,omic technological interventions have enabled determination of the shift in soil microbe community at a taxa level, which can provide very important inputs for modeling C sequestration process. The intricacy and diversity of the soil microbial population and how it responds to climate change are big challenges, but new molecular and stable isotope probing tools are being developed for linking fluctuations in microbial diversity to ecosystem function.
基金Supported by China Earthquake Administration under Grant No.20150112National Natural Science Foundation of China under Grant No.21504014
文摘The present paper develops the scaling theory of polyelectrolyte nanogels in dilute and semidilute solutions. The dependencies of the nanogel dimension on branching topology, charge fraction, subchain length, segment number, solution concentration are obtained. For a single polyeleetrolyte nanogel in salt free solution, the nanogel may be swelled by the Coulombie repulsion （the so-called polyelectrolyte regime） or the osmotic eounterion pressure （the so-called osmotic regime）. Characteristics and boundaries between different regimes of a single polyelectrolyte nanogel are summarized. In dilute solution, the nanogels in polyeleetrolyte regime will distribute orderly with the increase of concentration. While the nanogels in osmotic regime will always distribute randomly. Different concentration dependencies of the size of a nanogel in polyeleetrolyte regime and in osmotic regime are also explored.
