锌离子传导聚合物缓冲层:抑制锌离子水电池锌负极寄生反应

由于锌金属在电解液中热力学不稳定而自发地发生寄生反应(析氢、枝晶生长等),水系锌离子电池的商业化应用受到了阻碍.因此,我们构建了一种高粘附性的锌离子传导聚合物聚乙烯醇缩甲醛(PVF)缓冲层,来抑制这些寄生反应的发生,从而提高锌沉积的可逆性.这种致密的人工缓冲层不仅能有效隔绝电解质与锌负极之间的直接接触,还能适应锌沉积/剥离过程中的体积膨胀,并引导锌成核过程.具体来说,PVF层可提高成核过电位,并促进Zn2+的三维扩散过程,使PVF层下的Zn2+沉积通量均匀化.我们设计的PVF@Zn具有高循环稳定性和不易生成枝晶的特点,基于该电极的对称电池的长循环寿命超过5200 h,比Zn负极电池提高了近35倍,甚至可以在40.0 mA cm^(−2)的超高电流密度下稳定运行.此外,PVF@Zn||NVO全电池在1.0 A g^(−1)的条件下进行2400个循环后,仍能保持172.4 mA h g^(−1)的比容量.这种通过消除自发寄生反应并调节锌均匀沉积及成核的策略,为设计实用化高性能锌负极提供了重要借鉴.

Phosphodiesterase 10A inhibitor PF-2545920 as a prospective agent for the clinical promotion of sperm motility

Phosphodiesterase(PDE)inhibitors can improve sperm motility in patients with asthenozoospermia.However,the most commonly reported nonselective PDE inhibitor pentoxifylline and PDE5 inhibitor sildenafil have the disadvantages of requiring a high concentration and destroying sperm integrity.We examined the PDE10A inhibitor PF-2545920 to compare its ability to promote sperm motility with that of pentoxifylline and sildenafil.After seminal plasma was discarded,several semen samples were subjected to four treatments(control,PF-2545920,pentoxifylline,and sildenafil)to evaluate their ability to affect motility,viability,and spontaneous acrosome reactions.Intracellular calcium and adenosine triphosphate(ATP),mitochondrial membrane potential,and penetration through viscous medium were assessed by flow cytometry,luciferase,and hyaluronic acid after treatment with PF-2545920.Statistical analyses were performed using the analysis of variance statistical test.PF-2545920 elevated the percentage of motile spermatozoa compared to the control,pentoxifylline,and sildenafil groups at 10μmol l^(-1)(P<0.01).It is less toxic to GC-2spd mouse spermatocytes cells and spermatozoa and causes fewer spontaneous acrosomal reactions(P<0.05).PF-2545920 also increased mitochondrial membrane potential(P<0.001)and altered intracellular calcium(P<0.05)in a dose-dependent manner,including increasing sperm hyaluronic acid penetrating ability(P<0.05).Therefore,PF-2545920 might be an excellent choiceforstimulatingthe spermmotility.

Dissociation of liquid water on defective rutile TiO2 （110） surfaces using ab initio molecular dynamics simulations

In order to obtain a comprehensive understanding of both thermodynamics and kinetics of water dissociation on TiO2, the reactions between liquid water and perfect and defective rutile TiO2 （110） surfaces were investigated using ab initio molecular dynamics simulations. The results showed that the free-energy barrier （-4.4 kcal/mol） is too high for a spontaneous dissociation of water on the perfect rutile （110） surface at a low temperature. The most stable oxygen vacancy （VOl） on the rutile （110） surface cannot promote the dissociation of water, while other unstable oxygen vacancies can significantly enhance the water dissociation rate. This is opposite to the general understanding that Vol defects are active sites for water dissociation. Furthermore, we reveal that water dissociation is an exothermic reaction, which demonstrates that the dissociated state of the adsorbed water is thermodynamically favorable for both perfect and defective futile （110） surfaces. The dissociation adsorption of water can also increase the hydrophilicity of TiO2.