Oxygen-coordinated low-nucleus cluster catalysts for enhanced electrocatalytic water oxidation

The oxygen evolution reaction(OER)activity of single-atom catalysts(SACs)is closely related to the coordination environment of the active site.Oxygencoordinated atomic metal species bring about unique features beyond nitrogen-coordinated atomic metal species due to the fact that the M-O bond is weaker than the M-N bond.Herein,a series of metal-oxygen-carbon structured low-nucleus clusters(LNCs)are successfully anchored on the surface of multiwalled carbon nanotubes(M-MWCNTs,M=Ni,Co,or Fe)through a foolproof low-temperature gas transfer(300℃)method without any further treatment.The morphology and coordination configuration of the LNCs at the atomic level were confirmed by comprehensive characterizations.The synthetic Ni-MWCNTs electrocatalyst features excellent OER activity and stability under alkaline conditions,transcending the performances of Co-MWCNTs,Fe-MWCNTs and RuO_(2).Density functional theory calculations reveal that the moderate oxidation of low-nucleus Ni clusters changes the unoccupied orbital of Ni atoms,thereby lowering the energy barrier of the OER rate-limiting step and making the OER process more energy-efficient.This study demonstrates a novel versatile platform for large-scale manufacturing of oxygen-coordinated LNC catalysts.

Antioxidant procyanidin B2 protects oocytes against cryoinjuries via mitochondria regulated cortical tension

Background:Irreversible cryodamage caused by oocyte vitrification limited its wild application in female fertility preservation.Antioxidants were always used to antagonist the oxidative stress caused by vitrification.However,the comprehensive mechanism underlying the protective role of antioxidants has not been studied.Procyanidin B2(PCB2)is a potent natural antioxidant and its functions in response to vitrification are still unknown.In this study,the effects of PCB2 on vitrified-thawed oocytes and subsequent embryo development were explored,and the mechanisms underlying the protective role of PCB2 were systematically elucidated.Results:Vitrification induced a marked decline in oocyte quality,while PCB2 could improve oocyte viability and further development after parthenogenetic activation.A subsequent study indicated that PCB2 effectively attenuated vitrification-induced oxidative stress,rescued mitochondrial dysfunction,and improved cell viability.Moreover,PCB2 also acts as a cortical tension regulator apart from strong antioxidant properties.Increased cortical tension caused by PCB2 would maintain normal spindle morphology and promote migration,ensure correct meiosis progression and finally reduce the aneuploidy rate in vitrified oocytes.Further study reveals that ATP biosynthesis plays a crucial role in cortical tension regulation,and PCB2 effectively increased the cortical tension through the electron transfer chain pathway.Additionally,PCB2 would elevate the cortical tension in embryo cells at morula and blastocyst stages and further improve blastocyst quality.What's more,targeted metabolomics shows that PCB2 has a beneficial effect on blastocyst formation by mediating saccharides and amino acids metabolism.Conclusions:Antioxidant PCB2 exhibits multi-protective roles in response to vitrification stimuli through mitochondria-mediated cortical tension regulation.

Recent progress and strategies toward high performance zinc-organic batteries

Energy sustainable development has stimulated the pursuit of an eco-friendly energy storage system.Carbon peak and neutrality targets oriented energy storage development will guide the way of further studies on batteries system.However,conventional batteries system(lead-acid batteries,lithium-ion batteries)based on ungreen transition metal oxide,flammable electrolytes or hazardous metals cannot keep pace with the development of society sooner or later.Thus,vast explorations on the advanced rechargeable battery systems were conducted.Compared with other battery systems,zinc ion battery systems with inherent safety,low cost were widely investigated.Especially,the zinc organic batteries based on the eco-efficiency organic cathodes were promising alternative advanced batteries for future energy storage systems.Therefore,various organics and different electrochemistry mechanisms were explored in the zinc batteries system.Herein,a timely review on elaborate analysis about functional groups,fundamentals,progress accompanied by the discussion on the four core issues:voltage,capacity,rate performance,cycle life was presented.Specifically,aiming at these issues,three levels of solution strategies:materials design concepts,morphology structure optimization and electrolyte environment were summarized and proposed for the development and innovation of zinc organic batteries.

Enriched endoplasmic reticulum-mitochondria interactions result in mitochondrial dysfunction and apoptosis in oocytes from obese mice

Background： Maternal obesity alters oocytes and subsequent fetal metabolism. An increasing number of studies have shown that the endoplasmic reticulums（ER） or mitochondria have important effects on oocyte quality, but there has been no study of the effect of mitochondria-associated ER membranes（MAMs） on oocyte quality. The present study was designed to assess whether the level of MAM and MAM-related proteins were different in oocytes from obese and control mice.Results： First, oocytes from mice with high-fat-diet（HFD）-induced obesity had higher levels（either greater numbers or a higher proportion for the same numbers） of MAM than oocytes from control mice. The abundance of MAM-related proteins in oocytes from obese mice was significantly greater at both the messenger RNA and protein levels, including inositol 1,4,5-trisphosphate receptor, type 1（IP3R1）, inositol 1,4,5-trisphosphate receptor,type 2（IP3 R2） and phosphofurin acidic cluster sorting protein 2（PACS-2）. Further, there was an increase in mitochondrial Ca^（2＋）（[Ca^（2＋）]_m） which was associated with increased apoptosis and compromised cytoplasmic maturation in oocytes from obese mice. Down-regulation of MAM-related protein IP3R1 in oocytes from obese mice decreased [Ca^2＋]_mand apoptosis and improved cytoplasmic maturation but did not reduce the overal MAM level. However, down-regulating MAM-related protein PACS-2 in oocytes from obese mice did reduce the level of MAM and [Ca^（2＋）]_m, which decreased the rate of apoptosis and improved cytoplasmic maturation of oocytes from obese mice.Conclusions： It is possible that enriched MAM could increase [Ca^（2＋）]_m, and this increase has been found to be associated with increased apoptosis and compromised cytoplasmic maturation in oocytes from obese mice. This finding suggests a novel therapeutic target for obesity-induced oocyte defects.

An efficient method for the sanitary vitrification of bovine oocytes in straws

Background：At present,vitrification has been widely applied to humans,mice and farm animals.To improve the efficiency of vitrification in straw,bovine oocytes were used to test a new two-step vitrification method in this study.Results：When in vitro matured oocytes were exposed to 20%ethylene glycol（EG20） for 5 min and 40%ethylene glycol（EG40） for 30 s,followed by treatment with 30%glycerol（Gly30）,Gly40 or Gly50,a volume expansion was observed in Gly30 and Gly40 but not Gly50.This indicates that the intracellular osmotic pressure after a 30 s differs between EG40 and ranged between Gly40（approximately 5.6 mol/L） and Gly50（approximately 7.0 mol/L）.Since oocytes are in EG40 just for only a short period of time（30 s） and at a lower temperature（4℃）,we hypothesize that the main function of this step in to induce dehydration.Based on these results,we omitted the EG40 step,before oocytes were pretreated in EG20 for 5 min,exposed to pre-cooled（4℃） Gly50,for 30 s,and then dipped into liquid nitrogen.After warming,81.1%of the oocytes survived,and the surviving oocytes developed into cleavage stage embryos（63.5%） or blastocysts（20.0%） after parthenogenetic activation.Conclusions：These results demonstrate that in a two-step vitrification procedure,the permeability effect in the second step is not necessary.It is possible that the second step is only required to provide adequate osmotic pressure to condense the intracellular concentration of CPAs to a level required for successful vitrification.

Direct Conversion of Methane to Propylene

Nonoxidative coupling of methane exhibits promising prospect in that it affords value-added hydrocarbons and hydrogen with high atom economy.However,challenge remains in direct,selective conversion of methane to more valuable hydrocarbons like olefins.The current work presents a catalyst with well-dispersed Ta atoms anchored by graphitic C_(3)N_(4)-supported phthalocyanine.Such a catalyst is able to convert methane selectively to ethylene and propylene at a relatively low temperature(350℃).The conception of the active center and construction of the catalyst have been described,and the origins of the catalytic performance are discussed.

Cryopreservation of farm animal gametes and embryos:recent updates and progress

Cryopreservation has undergone tremendous advances and is widely used in animal production based on decades of study of cellular permeability, freezability and empirical generalization. Several improvement are particularly important: the cryopreservation protocol has been continuously re?ned over the years to achieve greater reproductive performance; cryoprotective agents are more effective and less toxic than previously; there has been signi?cant innovation in advanced cryopreservation systems and carriers. Despite this, there are still problems that urgently require practical solutions, such as remedies for cryodamage and encouraging the use of frozen–thawed porcine sperm in pig production.