The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divale...The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divalent calcium(Ca^(2+))and magnesium(Mg^(2+))ions are at the subnanometer scale in diameter,similar to target monovalent ions,making ion separation a great challenge.Here,we propose a simple and fast secondary growth method for the preparation of MIL-53(Al)-NH_(2)membranes on the surface of anodic aluminum oxide.Such membranes contain angstrom-scale(~7Å)channels for the entrance of small monovalent ions and water molecules,endowing the selectivities for monovalent cations over divalent cations and water over salt molecules.The resulting high-connectivity MIL-53(Al)-NH_(2)membranes exhibit excellent ion separation performance(a selectivity of 121.42 for Na^(+)/Ca^(2+)and 93.81 for Li^(+)/Mg^(2+))and desalination performance(a water/salt selectivity of up to 5196).This work highlights metal–organic framework membranes as potential candidates for realizing ion separation and desalination in liquid treatment.展开更多
Objective To investigate the protective effects of hydrogen peroxide preconditioning (HPP) on the pheochromocytoma (PC12) cells treated with 1-methyl-4-phenylpyridinium (MPP^+) and to explore the potential mech...Objective To investigate the protective effects of hydrogen peroxide preconditioning (HPP) on the pheochromocytoma (PC12) cells treated with 1-methyl-4-phenylpyridinium (MPP^+) and to explore the potential mechanisms. Methods The viability and apoptosis of PC 12 cells were determinded by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 4′,6′-diamidino-2-phenylindole (DAPI) staining, respectively. The expressions of 14-3-3 protein and phospholylated p38 mitogen-activated protein kinase (MAPK) were determined by Western blot. Enzyme-linked immunosorbent assay (ELISA) was used to measure the activity of extracellular signal-regulated protein kinase 1/2 (ERK1/2). Results The cell viability decreased and the number of apoptotic cells increased dramatically in MPP^+ group compared with that in Control group. HPP induced a significant increase in cell viability and a marked decrease in population of apoptotic cells of the MPP^+- treated PC 12 cells, accompanied with up-regulation of 14-3-3 protein and increase of ERK 1/2 and p38 MAPK activities. The 14-3-3 protein expression was positively correlated with the phosphorylation of ERK1/2. Furthermore, inhibition of the ERK1/2 with PD98059 abolished the 14-3-3 protein up-regulation in PC 12 cells induced by HPP. Conclusion HPP protects PC 12 cells against MPP+ toxicity by up-regulating 14-3-3 protein expression through the ERK1/2 and p38 MAPK signaling pathways.展开更多
The finite element model is established according to the experimental results,and then the experimental results are verified by simulation calculation.In terms of the combination of finite element analysis and experim...The finite element model is established according to the experimental results,and then the experimental results are verified by simulation calculation.In terms of the combination of finite element analysis and experiment,the effect of particle size of CuO and SnO_(2) on the stress,strain and microstructure of AgCuOSnO_(2) composite during hot extrusion was studied.The results illustrate that with the decrease of particle size,the dispersion of the second phase increases gradually,while the possibility of“tail shrinkage”of the billet decreases continuously;cubic CuO will evolve to fibrosis,and the degree of fibrosis will increase with the decrease of the particle size and ring clusters.Specifically,the degree of fibrosis at the middle end of the billet is higher than that at the front end,the degree of fibrosis at the front end is higher than that at the back end,and the degree of fibrosis on the surface is higher than that in the core;part of CuO fibers will bend,and the degree of buckling strength is positively correlated with the size of particles and their annular clusters.Additionally,there is fiber CuO in the front and back end of the billet that are inconsistent with the extrusion direction,and the degree of difference was negatively correlated with the particle size.展开更多
AIM: To understand the digestive stability and mechanism of release and intestinal uptake of pea ferritin iron in caco-2 cell line model.METHODS: Pea seed ferritin was purified using salt fractionation followed by g...AIM: To understand the digestive stability and mechanism of release and intestinal uptake of pea ferritin iron in caco-2 cell line model.METHODS: Pea seed ferritin was purified using salt fractionation followed by gel filtration chromatography.The bioavailability of ferritin iron was assessed using coupled in vitro digestion/Caco-2 cell model in the presence or absence of ascorbic acid and phytic acid.Caco-2 cell ferritin formation was used as a surrogate marker of iron uptake. Structural changes of pea ferritin under simulated gastric pH were characterized using electrophoresis, gel filtration and circular dichroism spectroscopy.RESULTS: The caco-2 cell ferritin formation was significantly increased (P 〈 0.001) with FeSO4 (19.3±9.8 ng/mg protein) and pea ferritin (13.9 ± 6.19 ng/mg protein) compared to the blank digest (3.7 ± 1.8 ng/mg protein). Ascorbic acid enhanced while phytic acid decreased the pea ferritin iron bioavailability. However,either in the presence or absence of ascorbic acid, the ferritin content of caco-2 cells was significantly less with pea ferritin than with FeSO4. At gastric pH, no band corresponding to ferritin was observed in the presence of pepsin either on native PAGE or SDS-PAGE. Gel filtration chromatography and circular dichroism spectroscopy revealed a pH dependent loss of quaternary and secondary structure.CONCLUSION: Under gastric conditions, the iron core of pea ferritin is released into the digestive medium due to acid induced structural alterations and dissociation of protein. The released iron interacts with dietary factors leading to modulation of pea ferritin iron bioavailability,resembling the typical characteristics of non-heme iron.展开更多
Jingang No. 2 Heimeiren is a new early-maturing watermelon vadety in small to middle size with strong disease resistance bred with ZK09 as female par- ant and ZS05 as male parent. As to whole growth period, the spring...Jingang No. 2 Heimeiren is a new early-maturing watermelon vadety in small to middle size with strong disease resistance bred with ZK09 as female par- ant and ZS05 as male parent. As to whole growth period, the spring crop grows for 90-110 d, the autumn crop grows for 70-80 d, and the fruit development period is 27-29 d. The fruit is oblong with a fruit shape index of 1.5, the average single fruit weight is 3.18 kg, and the fruit surface is smooth in deep green color with dark green netted stripes. The fruit flesh is bright red, crisp, with a soluble solid content in the center of 11.5%. The fruit has a peel thickness of 1.0 cm with high storage tolerance, good appearance and good commodity. The variety is suitable for Guangxi, Guangdong and Halnan.展开更多
In this paper, we extend the multiple Riccati equations rational expansion method by introducing a new ansatz. Using this method, many complexiton solutions of the (2+ 1 )-dimensional Nizhnik-Novikov-Veselov equati...In this paper, we extend the multiple Riccati equations rational expansion method by introducing a new ansatz. Using this method, many complexiton solutions of the (2+ 1 )-dimensional Nizhnik-Novikov-Veselov equations are obtained which include various combination of hyperbolic and trigonometric periodic function solutions, various combination of hyperbolic and rational function solutions, various combination of trigonometric periodic and rational function solutions, etc. The method can be also used to solve other nonlinear partial differential equations.展开更多
Residues of tetracycline antibiotics(TCs) in environments may be harmful to human.Due to their high polarities,it is extremely challenging to efficiently enrich TCs with low concentrations in natural waters for analys...Residues of tetracycline antibiotics(TCs) in environments may be harmful to human.Due to their high polarities,it is extremely challenging to efficiently enrich TCs with low concentrations in natural waters for analysis.In this work,a magnetic metal-organic framework Fe_(3)O_(4)@[Cu_(3)(btc)_(2)]was synthesized and applied as a dispersive micro-solid phase extraction adsorbent for TCs enrichment.Effects of dispersive micro-solid phase extraction conditions including extraction time,solution p H,and elution solvent on the extraction efficiencies of TCs were investigated.Results show that TCs could be enriched efficiently by Fe_(3)O_(4)@[Cu_(3)(btc)_(2)],and electrostatic interaction between TCs and Fe_(3)O_(4)@[Cu_(3)(btc)_(2)]dominated this process.Combined with liquid chromatography-tandem mass spectrometry,four TCs residues (oxytetracycline,tetracycline,chlortetracycline,and doxycycline) in natural waters were determined.The detection limits (LOD,S/N=3) of the four antibiotics were 0.01-0.02μg/L,and the limits of quantitation (LOQ,S/N=10)were 0.04-0.07μg/L.The recoveries obtained from river water and aquaculture water spiked with three TCs concentration levels ranged from 70.3%to 96.5%with relative standard deviations of 3.8%-12.8%.Results indicate that the magnetic metal-organic framework based dispersive micro-solid phase extraction is simple,rapid and high-loading for antibiotics enrichment from water,which further expand the practical application of metal-organic frameworks in sample pretreatment for environmental pollutant analysis.展开更多
The crystal of the title compound with formula C36H44Cl2F3Mo2NO8S2 (Mr = 10002.62) crystallized in monoclinic, space group P21/n, with a = 9.6184(1), b = 22.3476(2), c = 20.7758(2) ?, ( = 90.172(1)(, V = 4465.70(7) ?3...The crystal of the title compound with formula C36H44Cl2F3Mo2NO8S2 (Mr = 10002.62) crystallized in monoclinic, space group P21/n, with a = 9.6184(1), b = 22.3476(2), c = 20.7758(2) ?, ( = 90.172(1)(, V = 4465.70(7) ?3, Z = 4, Dc = 1.491 g/cm3, F(000) = 2032, ( = 0.833 mm-1, Final R = 0.0665 and wR = 0.1650 for 5044 reflections with I >2.0( (I). The crystal structure revealed that the Mo2S2 core is planar, and the trifluoroacetic group acts as a bidentate bridging ligand and coordinates to two Mo atoms forming a five-membered ring plane, in which the Mo-Mo bond distance is 2.9222(9) ? and the O-C-O angle is 131.8(7)展开更多
AIM To determine the role of G0/G1 switch gene 2(G0 S2) and its transcriptional regulation in palmitate-induced hepatic lipid accumulation.METHODS Hep G2 cells were treated with palmitate,or palmitate in combination w...AIM To determine the role of G0/G1 switch gene 2(G0 S2) and its transcriptional regulation in palmitate-induced hepatic lipid accumulation.METHODS Hep G2 cells were treated with palmitate,or palmitate in combination with CCAAT/enhancer binding protein(C/EBP)β si RNA or G0 S2 si RNA. The m RNA expression of C/EBPβ,peroxisome proliferator-activated receptor(PPAR)γ and PPARγ target genes(G0 S2,GPR81,GPR109 A and Adipoq) was examined by q PCR. The protein expression of C/EBPβ,PPARγ,and G0 S2 was determined by Western blotting. Lipid accumulation was detected with Oil Red O staining and quantified by absorbance value of the extracted Oil Red O dye. Lipolysis was evaluated by measuring the amount of glycerol released into the medium. RESULTS Palmitate caused a dose-dependent increase in lipid accumulation and a dose-dependent decrease in lipolysis in Hep G2 cells. In addition,palmitate increased the m RNA expression of C/EBPβ,PPARγ,and PPARγ target genes(G0 S2,GPR81,GPR109 A,and Adipoq) and the protein expression of C/EBPβ,PPARγ,and G0 S2 in a dose-dependent manner. Knockdown of C/EBPβ decreased palmitate-induced PPARγ and its target genes(G0 S2,GPR81,GPR109 A,and Adipoq) m RNA expression and palmitate-induced PPARγ and G0 S2 protein expression in Hep G2 cells. Knockdown of C/EBPβ also attenuated lipid accumulation and augmented lipolysis in palmitate-treated Hep G2 cells. G0 S2 knockdown attenuated lipid accumulation and augmented lipolysis,while G0 S2 knockdown had no effects on the m RNA expression of C/EBPβ,PPARγ,and PPARγ target genes(GPR81,GPR109 A and Adipoq) in palmitate-treated Hep G2 cells. CONCLUSION Palmitate can induce lipid accumulation in Hep G2 cells by activating C/EBPβ-mediated G0 S2 expression.展开更多
In this work, by means of a generalized method and symbolic computation, we extend the Jacobi elliptic function rational expansion method to uniformly construct a series of stochastic wave solutions for stochastic evo...In this work, by means of a generalized method and symbolic computation, we extend the Jacobi elliptic function rational expansion method to uniformly construct a series of stochastic wave solutions for stochastic evolution equations. To illustrate the effectiveness of our method, we take the (2+ 1)-dimensional stochastic dispersive long wave system as an example. We not only have obtained some known solutions, but also have constructed some new rational formal stochastic Jacobi elliptic function solutions.展开更多
The selective catalytic reduction (SCR) of NOx with NH3 has been proven to be an efficient technology for NOx conversion to N2. However, the catalysts used for SCR usually suffer from the problem of sulfur poisoning...The selective catalytic reduction (SCR) of NOx with NH3 has been proven to be an efficient technology for NOx conversion to N2. However, the catalysts used for SCR usually suffer from the problem of sulfur poisoning which seriously limits their practical application. This review summarized sulfur poisoning mechanisms of various SCR deNG catalysts and strategies to reduce deactivation caused by SO2 such as doping metals, controlling the structures and morphologies of the catalysts, and selecting appropriate supports. The methods and procedures of catalysts preparation and the reaction conditions also have effect on SO2-resistance of the catalysts. Several novel catalyst systems that exhibited good SO2 resistance are also introduced. This paper could provide guidance for the development of highly efficient sulfur-tolerant deNOx catalysts.展开更多
The transformation of CO_(2)into cyclic carbonates via atom-economical cycloadditions with epoxides has recently attracted tremendous attention.On one hand,though many heterogeneous catalysts have been developed for t...The transformation of CO_(2)into cyclic carbonates via atom-economical cycloadditions with epoxides has recently attracted tremendous attention.On one hand,though many heterogeneous catalysts have been developed for this reaction,they typically suffer from disadvantages such as the need for severe reaction conditions,catalyst loss,and large amounts of soluble co-catalysts.On the other hand,the development of heterogeneous catalysts featuring multiple and cooperative active sites,remains challenging and desirable.In this study,we prepared a series of porous organic catalysts(POP-PBnCl-TPPMg-x)via the copolymerization metal-porphyrin compounds and phosphonium salt monomers in various ratios.The resulting materials contain both Lewis-acidic and Lewis-basic active sites.The molecular-level combination of these sites in the same polymer allows these active sites to work synergistically,giving rise to excellent performance in the cycloaddition reaction of CO_(2)with epoxides,under mild conditions(40℃ and 1 atm CO_(2))in the absence of soluble co-catalysts.POP-PBnCl-TPPMg-12 can also efficiently fixate CO_(2)under low-CO_(2)-concentration(15%v/v N2)conditions representative of typical CO_(2)compositions in industrial exhaust gases.More importantly,this catalyst shows excellent recyclability and can easily be separated and reused at least five times while maintaining its activity.In view of their heterogeneous nature and excellent catalytic performance,the obtained catalysts are promising candidates for the transformation of industrially generated CO_(2)into high value-added chemicals.展开更多
MXenes are emerging two-dimensional(2D)nanomaterials composed of transition metal carbides and/or nitrides and possess unique layered structures with abundant surface functional groups,which enable them with excellent...MXenes are emerging two-dimensional(2D)nanomaterials composed of transition metal carbides and/or nitrides and possess unique layered structures with abundant surface functional groups,which enable them with excellent and tunable properties.MXenes films can be solution-processed in polar solvents and are very suitable for optoelectronic device applications.Especially,Ti_(3)C_(2)T_(x) MXene with the clear advantages of facile synthesis,flexible surface controlling,easily tunable work function,high optical transmittance and excellent conductivity shows great potential for applications in organic/perovskite optoelectronic devices.Therefore,this review briefly introduces the mainstream synthesis methods,optical and electrical properties of MXenes,and comprehensively summarizes the versatile applications of Ti_(3)C_(2)T_(x) MXene in different functional layers(electrode,interface layer and active layer)of organic/perovskite optoelectronic devices including solar cells and light-emitting diodes.Finally,the current application characteristics and the future possibilities of MXenes in organic/perovskite optoelectronic devices are concluded and discussed.展开更多
Hydrogen evolution reaction is a critical reaction in water splitting for hydrogen production.However,developing effective and stable non‐noble‐metal electrocatalysts which work well at high current densities demand...Hydrogen evolution reaction is a critical reaction in water splitting for hydrogen production.However,developing effective and stable non‐noble‐metal electrocatalysts which work well at high current densities demanded by industry still remain great challenge.Herein,taking advantage of the highly tunable metal‐organic framework(MOF)templates,nitrogen doped binary transition metal phosphides electrocatalysts(N‐CoP_(x)/Ni_(2)P)with three‐dimensional(3D)conductive network structure were successfully synthesized.The 3D open porous channels could expose more catalytically active sites;nitrogen doping and the synergistic effect between CoP and Ni_(2)P can increase the electron density of Co atoms at active sites,further optimizing the Gibbs free energy of hydrogen(ΔGH*)and water(ΔG_(H_(2)O*)).As a result,the obtained N‐CoP_(x)/Ni_(2)P catalyst exhibits extraordinary electrocatalytic activity in a wide pH range.Especially,it requires an extremely low overpotential of 152 mV to deliver a high current density of 650 mA cm^(–2) in alkaline media.This work may shed some light on the rational design of cheap electrocatalysts and electrode materials that work well at high current densities.展开更多
Optimum conditions for in vitro production of interleukin 2 (IL 2) like activity from the Peripheral blood lymphocytes (PBL) of an Indian major carp, Labeo rohita were studied. Culture supernatants were generated ...Optimum conditions for in vitro production of interleukin 2 (IL 2) like activity from the Peripheral blood lymphocytes (PBL) of an Indian major carp, Labeo rohita were studied. Culture supernatants were generated by culturing the PBL in RPMI-1640 media supplemented with Glutamine and 10% fetal bovine serum (FBS) and stimulating with two different mitogens: concanavalin A (Con A) and Phytohaemagglutinin (PHA) at different concentrations separately. Significantly (P 〈 0.01) higher proliferation response was obtained from the culture supematant stimulated with concanavalin A (Con A) at a concentration of 10 lag mLl. The effect of phorbol myristate acetate (PMA) was also studied by co-stimulating PBL with Con A and PHA separately and it was found to synergistically enhancing the stimulation index with Con A whereas the stimulation index remain unchanged with PHA. The Con A (10 μg mLl) stimulated PBL were also cultured at different cell density, incubation period and incubation temperature in order to optimize the in vitro L. rohita IL2 production. The IL2 like activity was studied by lymphocyte proliferation assay on 72 h Con A blasts using WST based assay technique. Significantly (P 〈 0.01) higher stimulation indices were obtained when the PBL were cultured at a cell density of 1 × 10^6 cells mL^-1 for 30-36 h at an incubation temperature of 30 ℃. The IL2 like activity was purified by DEAE-Sepharose anion exchange chromatography and recorded between 70-130 mM NaCI with peak activity at 110 Mm NaCI. The molecular weight of the factor responsible for IL2 like activity was found to be 15-17 KD.展开更多
Metal organic frameworks(MOFs)is a research hotspot in the solar fuel production and photo-degradation of pollutants field due to high surface area,rich metal/organic species,large pore volume,and adjustability of str...Metal organic frameworks(MOFs)is a research hotspot in the solar fuel production and photo-degradation of pollutants field due to high surface area,rich metal/organic species,large pore volume,and adjustability of structures and compositions.Therefore,in this review,we first summarized the design factors of photocatalytic materials based on MOF from the perspective of"star"MOF.The modification strategies of MOFs-based photocatalysts were discussed to improve its photocatalytic activity and specific applications were summarized as well,including photocatalytic CO_(2)reduction,photocatalytic water splitting and photo-degradation of pollutants.Finally,the advantages and disadvantages of MOFs-based photocatalysts were discussed,the current challenges were highlighted,and suggestions for future research directions were proposed.展开更多
The actual effective partition coefficients of Mg and Cr in a cross-section of a dendrite arm in a direct-chill(DC)-casting ingot of 7475 aluminum alloy are obtained.Meanwhile,by analyzing the microstructure,the mecha...The actual effective partition coefficients of Mg and Cr in a cross-section of a dendrite arm in a direct-chill(DC)-casting ingot of 7475 aluminum alloy are obtained.Meanwhile,by analyzing the microstructure,the mechanism of the heterogeneous distribution of E(Al_(18)Mg_(3)Cr_(2))dispersoids in this DC ingot is revealed.The results show that the actual effective partition coefficients of Mg and Cr are 0.650 and 1.392,respectively,and they describe the heterogeneous distributions of Mg and Cr along the direction of radius of the cross-section of the dendrite arm of the alloy.After homogenization treatment at 470℃ for 24 h,Mg diffuses uniformly,but Cr hardly diffuses.Both the concentrations of Mg and Cr and the sites of heterogeneous nucleation in the alloy are the determinants of the formation of E dispersoids simultaneously.The heat treatment at 250℃ for 72 h provides a large number of the sites of heterogeneous nucleation of the formation of fine E dispersoids that will be formed in the center of the cross-section during the subsequent heat treatment at higher temperature.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(WK2060000030)USTC Research Funds of the Double First Class Initiative(YD2060002022)Major Science and Technology Innovation Projects in Shandong Province(2022CXGC020415).
文摘The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divalent calcium(Ca^(2+))and magnesium(Mg^(2+))ions are at the subnanometer scale in diameter,similar to target monovalent ions,making ion separation a great challenge.Here,we propose a simple and fast secondary growth method for the preparation of MIL-53(Al)-NH_(2)membranes on the surface of anodic aluminum oxide.Such membranes contain angstrom-scale(~7Å)channels for the entrance of small monovalent ions and water molecules,endowing the selectivities for monovalent cations over divalent cations and water over salt molecules.The resulting high-connectivity MIL-53(Al)-NH_(2)membranes exhibit excellent ion separation performance(a selectivity of 121.42 for Na^(+)/Ca^(2+)and 93.81 for Li^(+)/Mg^(2+))and desalination performance(a water/salt selectivity of up to 5196).This work highlights metal–organic framework membranes as potential candidates for realizing ion separation and desalination in liquid treatment.
基金the National Natural Science Foundation of China (No. 30570627)
文摘Objective To investigate the protective effects of hydrogen peroxide preconditioning (HPP) on the pheochromocytoma (PC12) cells treated with 1-methyl-4-phenylpyridinium (MPP^+) and to explore the potential mechanisms. Methods The viability and apoptosis of PC 12 cells were determinded by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and 4′,6′-diamidino-2-phenylindole (DAPI) staining, respectively. The expressions of 14-3-3 protein and phospholylated p38 mitogen-activated protein kinase (MAPK) were determined by Western blot. Enzyme-linked immunosorbent assay (ELISA) was used to measure the activity of extracellular signal-regulated protein kinase 1/2 (ERK1/2). Results The cell viability decreased and the number of apoptotic cells increased dramatically in MPP^+ group compared with that in Control group. HPP induced a significant increase in cell viability and a marked decrease in population of apoptotic cells of the MPP^+- treated PC 12 cells, accompanied with up-regulation of 14-3-3 protein and increase of ERK 1/2 and p38 MAPK activities. The 14-3-3 protein expression was positively correlated with the phosphorylation of ERK1/2. Furthermore, inhibition of the ERK1/2 with PD98059 abolished the 14-3-3 protein up-regulation in PC 12 cells induced by HPP. Conclusion HPP protects PC 12 cells against MPP+ toxicity by up-regulating 14-3-3 protein expression through the ERK1/2 and p38 MAPK signaling pathways.
基金Project(2017FA027)supported by the Key Project of Science and Technology of Yunnan Province,China。
文摘The finite element model is established according to the experimental results,and then the experimental results are verified by simulation calculation.In terms of the combination of finite element analysis and experiment,the effect of particle size of CuO and SnO_(2) on the stress,strain and microstructure of AgCuOSnO_(2) composite during hot extrusion was studied.The results illustrate that with the decrease of particle size,the dispersion of the second phase increases gradually,while the possibility of“tail shrinkage”of the billet decreases continuously;cubic CuO will evolve to fibrosis,and the degree of fibrosis will increase with the decrease of the particle size and ring clusters.Specifically,the degree of fibrosis at the middle end of the billet is higher than that at the front end,the degree of fibrosis at the front end is higher than that at the back end,and the degree of fibrosis on the surface is higher than that in the core;part of CuO fibers will bend,and the degree of buckling strength is positively correlated with the size of particles and their annular clusters.Additionally,there is fiber CuO in the front and back end of the billet that are inconsistent with the extrusion direction,and the degree of difference was negatively correlated with the particle size.
基金Supported by a grant No. BT/PR6728/AGR/02/334/2005 from the Department of Biotechnology, Government of India to KMN and RP, SB is supported by a Research Fellowship from the Indian Council of Medical Research
文摘AIM: To understand the digestive stability and mechanism of release and intestinal uptake of pea ferritin iron in caco-2 cell line model.METHODS: Pea seed ferritin was purified using salt fractionation followed by gel filtration chromatography.The bioavailability of ferritin iron was assessed using coupled in vitro digestion/Caco-2 cell model in the presence or absence of ascorbic acid and phytic acid.Caco-2 cell ferritin formation was used as a surrogate marker of iron uptake. Structural changes of pea ferritin under simulated gastric pH were characterized using electrophoresis, gel filtration and circular dichroism spectroscopy.RESULTS: The caco-2 cell ferritin formation was significantly increased (P 〈 0.001) with FeSO4 (19.3±9.8 ng/mg protein) and pea ferritin (13.9 ± 6.19 ng/mg protein) compared to the blank digest (3.7 ± 1.8 ng/mg protein). Ascorbic acid enhanced while phytic acid decreased the pea ferritin iron bioavailability. However,either in the presence or absence of ascorbic acid, the ferritin content of caco-2 cells was significantly less with pea ferritin than with FeSO4. At gastric pH, no band corresponding to ferritin was observed in the presence of pepsin either on native PAGE or SDS-PAGE. Gel filtration chromatography and circular dichroism spectroscopy revealed a pH dependent loss of quaternary and secondary structure.CONCLUSION: Under gastric conditions, the iron core of pea ferritin is released into the digestive medium due to acid induced structural alterations and dissociation of protein. The released iron interacts with dietary factors leading to modulation of pea ferritin iron bioavailability,resembling the typical characteristics of non-heme iron.
文摘Jingang No. 2 Heimeiren is a new early-maturing watermelon vadety in small to middle size with strong disease resistance bred with ZK09 as female par- ant and ZS05 as male parent. As to whole growth period, the spring crop grows for 90-110 d, the autumn crop grows for 70-80 d, and the fruit development period is 27-29 d. The fruit is oblong with a fruit shape index of 1.5, the average single fruit weight is 3.18 kg, and the fruit surface is smooth in deep green color with dark green netted stripes. The fruit flesh is bright red, crisp, with a soluble solid content in the center of 11.5%. The fruit has a peel thickness of 1.0 cm with high storage tolerance, good appearance and good commodity. The variety is suitable for Guangxi, Guangdong and Halnan.
基金The project partially supported by the State Key Basic Research Program of China under Grant No. 2004CB318000 .
文摘In this paper, we extend the multiple Riccati equations rational expansion method by introducing a new ansatz. Using this method, many complexiton solutions of the (2+ 1 )-dimensional Nizhnik-Novikov-Veselov equations are obtained which include various combination of hyperbolic and trigonometric periodic function solutions, various combination of hyperbolic and rational function solutions, various combination of trigonometric periodic and rational function solutions, etc. The method can be also used to solve other nonlinear partial differential equations.
基金supported by the National Natural Science Foundation of China(No.21607003).
文摘Residues of tetracycline antibiotics(TCs) in environments may be harmful to human.Due to their high polarities,it is extremely challenging to efficiently enrich TCs with low concentrations in natural waters for analysis.In this work,a magnetic metal-organic framework Fe_(3)O_(4)@[Cu_(3)(btc)_(2)]was synthesized and applied as a dispersive micro-solid phase extraction adsorbent for TCs enrichment.Effects of dispersive micro-solid phase extraction conditions including extraction time,solution p H,and elution solvent on the extraction efficiencies of TCs were investigated.Results show that TCs could be enriched efficiently by Fe_(3)O_(4)@[Cu_(3)(btc)_(2)],and electrostatic interaction between TCs and Fe_(3)O_(4)@[Cu_(3)(btc)_(2)]dominated this process.Combined with liquid chromatography-tandem mass spectrometry,four TCs residues (oxytetracycline,tetracycline,chlortetracycline,and doxycycline) in natural waters were determined.The detection limits (LOD,S/N=3) of the four antibiotics were 0.01-0.02μg/L,and the limits of quantitation (LOQ,S/N=10)were 0.04-0.07μg/L.The recoveries obtained from river water and aquaculture water spiked with three TCs concentration levels ranged from 70.3%to 96.5%with relative standard deviations of 3.8%-12.8%.Results indicate that the magnetic metal-organic framework based dispersive micro-solid phase extraction is simple,rapid and high-loading for antibiotics enrichment from water,which further expand the practical application of metal-organic frameworks in sample pretreatment for environmental pollutant analysis.
文摘The crystal of the title compound with formula C36H44Cl2F3Mo2NO8S2 (Mr = 10002.62) crystallized in monoclinic, space group P21/n, with a = 9.6184(1), b = 22.3476(2), c = 20.7758(2) ?, ( = 90.172(1)(, V = 4465.70(7) ?3, Z = 4, Dc = 1.491 g/cm3, F(000) = 2032, ( = 0.833 mm-1, Final R = 0.0665 and wR = 0.1650 for 5044 reflections with I >2.0( (I). The crystal structure revealed that the Mo2S2 core is planar, and the trifluoroacetic group acts as a bidentate bridging ligand and coordinates to two Mo atoms forming a five-membered ring plane, in which the Mo-Mo bond distance is 2.9222(9) ? and the O-C-O angle is 131.8(7)
基金Supported by the grants from the Natural Science Foundation of Shanxi Province,China,No.2014011043-1the Social Development Project of Jinzhong,Shanxi Province,No.S1601
文摘AIM To determine the role of G0/G1 switch gene 2(G0 S2) and its transcriptional regulation in palmitate-induced hepatic lipid accumulation.METHODS Hep G2 cells were treated with palmitate,or palmitate in combination with CCAAT/enhancer binding protein(C/EBP)β si RNA or G0 S2 si RNA. The m RNA expression of C/EBPβ,peroxisome proliferator-activated receptor(PPAR)γ and PPARγ target genes(G0 S2,GPR81,GPR109 A and Adipoq) was examined by q PCR. The protein expression of C/EBPβ,PPARγ,and G0 S2 was determined by Western blotting. Lipid accumulation was detected with Oil Red O staining and quantified by absorbance value of the extracted Oil Red O dye. Lipolysis was evaluated by measuring the amount of glycerol released into the medium. RESULTS Palmitate caused a dose-dependent increase in lipid accumulation and a dose-dependent decrease in lipolysis in Hep G2 cells. In addition,palmitate increased the m RNA expression of C/EBPβ,PPARγ,and PPARγ target genes(G0 S2,GPR81,GPR109 A,and Adipoq) and the protein expression of C/EBPβ,PPARγ,and G0 S2 in a dose-dependent manner. Knockdown of C/EBPβ decreased palmitate-induced PPARγ and its target genes(G0 S2,GPR81,GPR109 A,and Adipoq) m RNA expression and palmitate-induced PPARγ and G0 S2 protein expression in Hep G2 cells. Knockdown of C/EBPβ also attenuated lipid accumulation and augmented lipolysis in palmitate-treated Hep G2 cells. G0 S2 knockdown attenuated lipid accumulation and augmented lipolysis,while G0 S2 knockdown had no effects on the m RNA expression of C/EBPβ,PPARγ,and PPARγ target genes(GPR81,GPR109 A and Adipoq) in palmitate-treated Hep G2 cells. CONCLUSION Palmitate can induce lipid accumulation in Hep G2 cells by activating C/EBPβ-mediated G0 S2 expression.
基金The project partially supported by the State Key Basic Research Program of China under Grant No. 2004CB318000
文摘In this work, by means of a generalized method and symbolic computation, we extend the Jacobi elliptic function rational expansion method to uniformly construct a series of stochastic wave solutions for stochastic evolution equations. To illustrate the effectiveness of our method, we take the (2+ 1)-dimensional stochastic dispersive long wave system as an example. We not only have obtained some known solutions, but also have constructed some new rational formal stochastic Jacobi elliptic function solutions.
基金Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministrythe National Natural Science Foundation of China(21506150)
文摘The selective catalytic reduction (SCR) of NOx with NH3 has been proven to be an efficient technology for NOx conversion to N2. However, the catalysts used for SCR usually suffer from the problem of sulfur poisoning which seriously limits their practical application. This review summarized sulfur poisoning mechanisms of various SCR deNG catalysts and strategies to reduce deactivation caused by SO2 such as doping metals, controlling the structures and morphologies of the catalysts, and selecting appropriate supports. The methods and procedures of catalysts preparation and the reaction conditions also have effect on SO2-resistance of the catalysts. Several novel catalyst systems that exhibited good SO2 resistance are also introduced. This paper could provide guidance for the development of highly efficient sulfur-tolerant deNOx catalysts.
文摘The transformation of CO_(2)into cyclic carbonates via atom-economical cycloadditions with epoxides has recently attracted tremendous attention.On one hand,though many heterogeneous catalysts have been developed for this reaction,they typically suffer from disadvantages such as the need for severe reaction conditions,catalyst loss,and large amounts of soluble co-catalysts.On the other hand,the development of heterogeneous catalysts featuring multiple and cooperative active sites,remains challenging and desirable.In this study,we prepared a series of porous organic catalysts(POP-PBnCl-TPPMg-x)via the copolymerization metal-porphyrin compounds and phosphonium salt monomers in various ratios.The resulting materials contain both Lewis-acidic and Lewis-basic active sites.The molecular-level combination of these sites in the same polymer allows these active sites to work synergistically,giving rise to excellent performance in the cycloaddition reaction of CO_(2)with epoxides,under mild conditions(40℃ and 1 atm CO_(2))in the absence of soluble co-catalysts.POP-PBnCl-TPPMg-12 can also efficiently fixate CO_(2)under low-CO_(2)-concentration(15%v/v N2)conditions representative of typical CO_(2)compositions in industrial exhaust gases.More importantly,this catalyst shows excellent recyclability and can easily be separated and reused at least five times while maintaining its activity.In view of their heterogeneous nature and excellent catalytic performance,the obtained catalysts are promising candidates for the transformation of industrially generated CO_(2)into high value-added chemicals.
基金Projects(52063010,51961010)supported by the National Natural Science Foundation of China。
文摘MXenes are emerging two-dimensional(2D)nanomaterials composed of transition metal carbides and/or nitrides and possess unique layered structures with abundant surface functional groups,which enable them with excellent and tunable properties.MXenes films can be solution-processed in polar solvents and are very suitable for optoelectronic device applications.Especially,Ti_(3)C_(2)T_(x) MXene with the clear advantages of facile synthesis,flexible surface controlling,easily tunable work function,high optical transmittance and excellent conductivity shows great potential for applications in organic/perovskite optoelectronic devices.Therefore,this review briefly introduces the mainstream synthesis methods,optical and electrical properties of MXenes,and comprehensively summarizes the versatile applications of Ti_(3)C_(2)T_(x) MXene in different functional layers(electrode,interface layer and active layer)of organic/perovskite optoelectronic devices including solar cells and light-emitting diodes.Finally,the current application characteristics and the future possibilities of MXenes in organic/perovskite optoelectronic devices are concluded and discussed.
文摘Hydrogen evolution reaction is a critical reaction in water splitting for hydrogen production.However,developing effective and stable non‐noble‐metal electrocatalysts which work well at high current densities demanded by industry still remain great challenge.Herein,taking advantage of the highly tunable metal‐organic framework(MOF)templates,nitrogen doped binary transition metal phosphides electrocatalysts(N‐CoP_(x)/Ni_(2)P)with three‐dimensional(3D)conductive network structure were successfully synthesized.The 3D open porous channels could expose more catalytically active sites;nitrogen doping and the synergistic effect between CoP and Ni_(2)P can increase the electron density of Co atoms at active sites,further optimizing the Gibbs free energy of hydrogen(ΔGH*)and water(ΔG_(H_(2)O*)).As a result,the obtained N‐CoP_(x)/Ni_(2)P catalyst exhibits extraordinary electrocatalytic activity in a wide pH range.Especially,it requires an extremely low overpotential of 152 mV to deliver a high current density of 650 mA cm^(–2) in alkaline media.This work may shed some light on the rational design of cheap electrocatalysts and electrode materials that work well at high current densities.
文摘Optimum conditions for in vitro production of interleukin 2 (IL 2) like activity from the Peripheral blood lymphocytes (PBL) of an Indian major carp, Labeo rohita were studied. Culture supernatants were generated by culturing the PBL in RPMI-1640 media supplemented with Glutamine and 10% fetal bovine serum (FBS) and stimulating with two different mitogens: concanavalin A (Con A) and Phytohaemagglutinin (PHA) at different concentrations separately. Significantly (P 〈 0.01) higher proliferation response was obtained from the culture supematant stimulated with concanavalin A (Con A) at a concentration of 10 lag mLl. The effect of phorbol myristate acetate (PMA) was also studied by co-stimulating PBL with Con A and PHA separately and it was found to synergistically enhancing the stimulation index with Con A whereas the stimulation index remain unchanged with PHA. The Con A (10 μg mLl) stimulated PBL were also cultured at different cell density, incubation period and incubation temperature in order to optimize the in vitro L. rohita IL2 production. The IL2 like activity was studied by lymphocyte proliferation assay on 72 h Con A blasts using WST based assay technique. Significantly (P 〈 0.01) higher stimulation indices were obtained when the PBL were cultured at a cell density of 1 × 10^6 cells mL^-1 for 30-36 h at an incubation temperature of 30 ℃. The IL2 like activity was purified by DEAE-Sepharose anion exchange chromatography and recorded between 70-130 mM NaCI with peak activity at 110 Mm NaCI. The molecular weight of the factor responsible for IL2 like activity was found to be 15-17 KD.
文摘Metal organic frameworks(MOFs)is a research hotspot in the solar fuel production and photo-degradation of pollutants field due to high surface area,rich metal/organic species,large pore volume,and adjustability of structures and compositions.Therefore,in this review,we first summarized the design factors of photocatalytic materials based on MOF from the perspective of"star"MOF.The modification strategies of MOFs-based photocatalysts were discussed to improve its photocatalytic activity and specific applications were summarized as well,including photocatalytic CO_(2)reduction,photocatalytic water splitting and photo-degradation of pollutants.Finally,the advantages and disadvantages of MOFs-based photocatalysts were discussed,the current challenges were highlighted,and suggestions for future research directions were proposed.
基金financially supported by the National Natural Science Foundation of China(No.51871043)Fundamental Research Funds for the Central Universities of China(No.N180212010)Liaoning Natural Science Foundation of China(No.2019-MS-113)。
文摘The actual effective partition coefficients of Mg and Cr in a cross-section of a dendrite arm in a direct-chill(DC)-casting ingot of 7475 aluminum alloy are obtained.Meanwhile,by analyzing the microstructure,the mechanism of the heterogeneous distribution of E(Al_(18)Mg_(3)Cr_(2))dispersoids in this DC ingot is revealed.The results show that the actual effective partition coefficients of Mg and Cr are 0.650 and 1.392,respectively,and they describe the heterogeneous distributions of Mg and Cr along the direction of radius of the cross-section of the dendrite arm of the alloy.After homogenization treatment at 470℃ for 24 h,Mg diffuses uniformly,but Cr hardly diffuses.Both the concentrations of Mg and Cr and the sites of heterogeneous nucleation in the alloy are the determinants of the formation of E dispersoids simultaneously.The heat treatment at 250℃ for 72 h provides a large number of the sites of heterogeneous nucleation of the formation of fine E dispersoids that will be formed in the center of the cross-section during the subsequent heat treatment at higher temperature.