以2,2-二(5-甲基-2-四氢呋喃基)丙烷为极性调节剂合成苯乙烯/异戊二烯/丁二烯聚合动力学

以正丁基锂(n-BuLi)为引发剂,2,2-二(5-甲基-2-四氢呋喃基)丙烷(DMOP)为极性调节剂,采用阴离子聚合法合成苯乙烯(St)-异戊二烯(Ip)-丁二烯(Bd)三元共聚物(SIBR),研究了不同DMOP/n-BuLi(摩尔比)和不同反应温度条件下的三元共聚合反应动力学及共聚物的微观结构,并与极性调节剂四氢呋喃(THF)进行了比较。结果表明,在单体质量分数为12%,St/Ip/Bd(质量比)为22/38/40,设计单臂相对分子质量为12×10~4的条件下,3种单体的聚合反应速率与单体浓度之间呈线性关系,随着DMOP/n-BuLi(摩尔比)的增大或聚合反应温度的升高,各单体聚合反应速率逐渐增大,聚合反应的假一级表观增长反应速率常数增大;当DMOP/n-BuLi为1.0时,3种单体St,Ip,Bd的Ea″分别为71.868 kJ/mol,53.553 kJ/mol,71.403 kJ/mol,频率因子分别为6.61×10^(10)min^(-1),5.68×10~7min^(-1),7.88×10^(10)min^(-1);随着DMOP与nBuLi摩尔比的增大或聚合反应温度的降低,共聚物中总1,2-结构含量和Ip3,4含量明显增加,而Bd1,4和Ip1,4结构含量明显减少;DMOP在用量较小的情况下其效果优于较大THF用量的情况,促进聚合反应速率的能力明显高于THF。

锡偶联星形嵌段苯乙烯-异戊二烯-丁二烯三元共聚物的制备及表征

采用阴离子聚合法成功制备了锡偶联星形嵌段苯乙烯(St)-异戊二烯(Ip)-丁二烯(Bd)三元共聚物。通过核磁共振、气相色谱、凝胶渗透色谱、透射电镜、动态力学分析等方法表征材料的结构与性能,并与通用橡胶进行性能对比。结果表明,St含量低于30%时,共聚物趋于无规分布,St含量高于35%时,苯乙烯嵌段结构产生,随着St含量的增加,共聚物侧基结构含量下降;三元共聚中St,Ip,Bd的转化率随总转化率的增加而逐渐增大; St含量较低时,共聚物微观相态均一,随St含量的增大,微观相态产生相分离,损耗峰向高温移动,宽度略有增加;嵌段共聚物的物理力学性能与其他橡胶材料相当,抗湿滑性优于通用胶,滚动阻力小于通用胶,是一种理想的轮胎胎面用橡胶材料。

Lymphangiogenesis contributes to exercise-induced physiological cardiac growth

Background:Promoting cardiac lymphangiogenesis exerts beneficial effects for the heart.Exercise can induce physiological cardiac growth with cardiomyocyte hypertrophy and increased proliferation markers in cardiomyocytes.However,it remains unclear whether and how lymphangiogenesis contributes to exercise-induced physiological cardiac growth.We aimed to investigate the role and mechanism of lymphangiogenesis in exercise-induced physiological cardiac growth.Methods:Adult C57 BL6/J mice were subjected to 3 weeks of swimming exercise to induce physiological cardiac growth.Oral treatment with vascular endothelial growth factor receptor 3(VEGFR3) inhibitor SAR1 3 1 675 was used to investigate whether cardiac lymphangiogenesis was required for exercise-induced physiological cardiac growth by VEGFR3 activation.Furthermore,human dermal lymphatic endothelial cell(LEC)-conditioned medium was collected to culture isolated neonatal rat cardiomyocytes to determine whether and how LECs could influence cardiomyocyte proliferation and hypertrophy.Results:Swimming exercise induced physiological cardiac growth accompanied by a remarkable increase of cardiac lymphangiogenesis as evidenced by increased density of lymphatic vessel endothelial hyaluronic acid receptor 1-positive lymphatic vessels in the heart and upregulated LYVE-1 and Podoplanin expressions levels.VEGFR3 was upregulated in the exercised heart,while VEGFR3 inhibitor SAR131675 attenuated exercise-induced physiological cardiac growth as evidenced by blunted myocardial hypertrophy and reduced proliferation marker Ki67 in cardiomyocytes,which was correlated with reduced lymphatic vessel density and downregulated LYVE-1 and Podoplanin in the heart upon exercise.Furthermore,LEC-conditioned medium promoted both hypertrophy and proliferation of cardiomyocytes and contained higher levels of insulinlike growth factor-1 and the extracellular protein Reelin,while LEC-conditioned medium from LECs treated with SAR131675 blocked these effects.Functional rescue assays further demonstrated that protein kinase B(AKT) activation,as well as reduced CCAAT enhancer-binding protein beta(C/EBPβ) and increased CBP/p300-interacting transactivators with E(glutamic acid)/D(aspartic acid)-rich-carboxylterminal domain 4(CITED4),contributed to the promotive effect of LEC-conditioned medium on cardiomyocyte hypertrophy and proliferation.Conclusion:Our findings reveal that cardiac lymphangiogenesis is required for exercise-induced physiological cardiac growth by VEGFR3 activation,and they indicate that LEC-conditioned medium promotes both physiological hypertrophy and proliferation of cardiomyocytes through AKT activation and the C/EBPβ-CITED4 axis.These results highlight the essential roles of cardiac lymphangiogenesis in exercise-induced physiological cardiac growth.

Experimental study on the membrane distillation of highly mineralized mine water

Membrane distillation(MD)is a promising membrane separation technique used to treat industrial wastewater.When coupled with cheap heat sources,MD has significant economic advantages.Therefore,MD can be combined with solar energy to realize the large-scale and low-cost treatment of highly mineralized mine water in the western coalproducing region of China.In this study,highly mineralized mine water from the Ningdong area of China was subjected to vacuum MD(VMD)using polyvinylidene fluoride hollow-fiber membranes.The optimal operation parameters of VMD were determined by response surface optimization.Subsequently,the feasibility of VMD for treating highly mineralized mine water was explored.The fouling behavior observed during VMD was further investigated by scanning electron microscopy with energy-dispersive X-ray spectroscopy(SEM-EDS).Under the optimal parameters(pressure=-0.08 MPa,temperature=70℃,and feed flow rate=1.5 L/min),the maximum membrane flux was 8.85 kg/(m^(2) h),and the desalination rate was 99.7%.Membrane fouling could be divided into three stages:membrane wetting,crystallization,and fouling layer formation.Physical cleaning restored the flux and salt rejection rate to 94%and 97%of the initial values,respectively;however,the cleaning interval and cleaning efficiency decreased as the VMD run time increased.SEM-EDS analysis revealed that the reduction in flux was caused by the precipitation of CaCO_(3).The findings also demonstrated that the membrane wetting could be attributed to the formation of NaCl on the cross section and outer surface of the membrane.Overall,the results confirm the feasibility of MD for treating mine water and provide meaningful guidance for the industrial application of MD.

Recent Progress in and Perspectives on Emerging Halide Superionic Conductors for All‑Solid‑State Batteries

Rechargeable all-solid-state batteries(ASSBs)are considered to be the next generation of devices for electrochemical energy storage.The development of solid-state electrolytes(SSEs)is one of the most crucial subjects in the field of energy storage chemistry.The newly emerging halide SSEs have recently been intensively studied for application in ASSBs due to their favorable combination of high ionic conductivity,exceptional chemical and electrochemical stability,and superior mechanical deformability.In this review,a critical overview of the development,synthesis,chemical stability and remaining challenges of halide SSEs is given.The design strategies for optimizing the ionic conductivity of halide SSEs,such as element substitution and crystal structure design,are summarized in detail.Moreover,the associated chemical stability issues in terms of solvent compatibility,humid air stability and corresponding degradation mechanisms are discussed.In particular,advanced in situ/operando characterization techniques applied to halide-based ASSBs are highlighted.In addition,a comprehensive understanding of the interface issues,cost issues,and scalable processing challenges faced by halide-based ASSBs for practical application is provided.Finally,future perspectives on how to design high-performance electrode/electrolyte materials are given,which are instructive for guiding the development of halide-based ASSBs for energy conversion and storage.

Solar photocatalytic decomposition of two azo dyes on multiwalled carbon nanotubes(MWCNTs)/TiO_(2)composites

Multi-walled carbon nanotubes(MWCNTs)/TiO_(2)composite photocatalysts with high photoactivity were prepared by sol-gel process and further characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier transform infrared(FT-IR),and UV-vis absorption spectra.Compared to pure TiO_(2),the combination of MWCNTs with titania could cause a significant absorption shift toward the visible region.The photocatalytic performances of the MWCNTs/TiO_(2)composite catalysts were evaluated for the decomposition of Reactive light yellow K-6G(K-6G)and Mordant black 7(MB 7)azo dyes solution under solar light irradiation.The results showed that the addition of MWCNTs enhanced the adsorption and photocatalytic activity of TiO_(2)for the degradation of azo dyes K-6G and MB 7.The effect of MWCNTs content,catalyst dosage,pH,and initial dye concentration were examined as operational parameters.The kinetics of photocatalytic degradation of two dyes was found to follow a pseudo-first-order rate law.The photocatalyst was used for seven cycles with photocatalytic degradation efficiency still higher than 98%.A plausible mechanism is also proposed and discussed on the basis of experimental results.

Water-dispersible nano-pollutions reshape microbial metabolism in type-specific manners:A metabolic and bacteriological investigation in Escherichia coli

Incomplete separation and recycling of nanoparticles are causing undesirable nanopollution and thus raising great concerns with regard to nanosafety.Since microorganisms are important regulator of physiological processes in many organisms,the interaction between nanopollution and microbial metabolomics and the resultant impact on the host’s health are important but unclear.To investigate how typical nanopollution perturbs microbial growth and metabolism,Escherichia coli(E.coli)in vitro was treated with six water-dispersible nanomaterials(nanoplastic,nanosilver,nano-TiO 2,nano-ZnO,semiconductor quantum dots(QDs),carbon dots(CDs))at human-/environment-relevant concentration levels.The nanomaterials exhibited type-specific toxic effects on E.coli growth.Global metabolite profiling was used to characterize metabolic disruption patterns in the model microorganism exposed to different nanopollutants.The percentage of significant metabolites(p<0.05,VIP>1)accounted for 6%–38%of the total 293 identified metabolites in each of the nanomaterial-contaminated bacterial groups.Metabolic results also exhibited significant differences between different nanopollutants and dose levels,revealing type-specific and untypical concentration-dependent metabolic responses.Key metabolites responsive to nanopollution exposures were mainly involved in amino acid and purine metabolisms,where 5,4,and 7 significant metabolic features were included in arginine and proline metabolism,phenylalanine metabolism,and purine metabolism,respectively.In conclusion,this study horizontally compared and demonstrated how typical nanopollution perturbs microbial growth and metabolomics in a type-specific manner,which broadens our understanding of the ecotoxicity of nanopollutants on microorganisms.