MORPHOLOGICAL TRANSITION BETWEEN VESICLES AND TUBULES FOR A GLYCOPOLYMER-CONTAINING AMPHIPHILIC DIBLOCK COPOLYMER IN AQUEOUS SOLUTIONS

The morphological transition of molecular assemblies in aqueous solutions for a new amphiphilic diblock copolymer induced by changing the initial solvent conditions was studied by transmission electron microscopy (TEM). The copolymer was polystyrene(77)-b-poly[2-(beta -D-glucopyranosyloxy)ethyl acrylate (6)] (PSt(77)-b-PGEA(6)) and the solvent was a mixture of DMF and THF. PSt(77)-b-PGEA(6) yields vesicles and tubules when it is initially dissolved in THF and DMF respectively. The morphological transition between vesicles and tubules can be achieved by simply varying the amounts of THF and DMF, or changing the temperature at which the aggregates were prepared.

A Practical Quantum Network Coding Protocol Based on Non-Maximally Entangled State

In many earlier works,perfect quantum state transmission over the butterfly network can be achieved via quantum network coding protocols with the assist of maximally entangled states.However,in actual quantum networks,a maximally entangled state as auxiliary resource is hard to be obtained or easily turned into a non-maximally entangled state subject to all kinds of environmental noises.Therefore,we propose a more practical quantum network coding scheme with the assist of non-maximally entangled states.In this paper,a practical quantum network coding protocol over grail network is proposed,in which the non-maximally entangled resource is assisted and even the desired quantum state can be perfectly transmitted.The achievable rate region,security and practicability of the proposed protocol are discussed and analyzed.This practical quantum network coding protocol proposed over the grail network can be regarded as a useful attempt to help move the theory of quantum network coding towards practicability.

Ferricyanide-Promoted Oxidative Activation and Ligation of Protein Thioacids in Neutral Aqueous Media

Ferricyanide-promoted oxidative activation of Nacylatedα-aminothioacids for amide bond formation withα-aminonitriles was recently shown to be a plausible pathway for prebiotic peptide synthesis.Herein we describe the finding that by adding sodium azide and thiols,ferricyanide oxidation can elicit highly efficient and clean conversion of fully unprotected peptide or protein thioacids in neutral aqueous media to the corresponding thioesters.This transformation enables the development of ferricyanide-promoted thioacid-based native chemical ligation(NCL)as a new redox-based method for chemical protein synthesis,which does not need to change pH and is therefore operationally easy for ligation at small scales.The effectiveness of the ferricyanide-promoted thioacid-based NCL was illustrated by synthesis of an ISG15-modified MDA5 segment under nondenaturing conditions and synthesis of an acetylated ubiquitin(Ub)-modified histone H2A through an N-to-C sequential ligation.This work broadens the concept of on-demand oxidative activation strategy for protein ligation and provides a new useful supplement to the repertoire of methods for chemical protein synthesis,particularly for studies on proteins carrying Ub family modifications.

Effects of Taohong Siwu Decoction on coagulation function and PI3K/AKT/mTOR pathway after femoral artery anastomosis in rabbits

Objective:To observe the effect of Taohong Siyu Decoction on the coagulation function and the signaling pathway of PI3K(phosphatidylinositol 3-kinase)/AKT(protein kinase B)/mTOR(mammalian target of rapamycin)after femoral artery anastomosis in rabbits.Methods:30 New Zealand white rabbits were divided into blank control group,model control group,papavine hydrochloride injection group and low,medium and high dose groups of Taohong Siwu decoction by random number table method,with 5 rabbits in each group.The rabbits in the model control group,papavine hydrochloride injection group and low,medium and high dose groups of Taohong Siwu decoction were treated with the femoral artery simple intermittent end-to-end suture model.After the successful modeling,the low,medium and high dose groups of Taohong Siwu decoction were given the Taohong Siwu decoction,while the model control group,the blank control group and papavine hydrochloride injection group were given the same amount of normal saline.APTT(activated partial thromboplastin time),FIB(fibrinogen)and PI3K/AKT/mTOR concentrations were measured in aural venous blood samples from six groups of rabbits 30min before operation and 1d,2D,3D and 7d after operation,respectively.Statistical analysis was conducted on the data of the six groups.Results:Compared with blank control group,APTT of model control group was significantly shortened 1d to 7d after operation(P<0.05),FIB values were significantly increased from 1d to 7d after operation(P<0.05);Compared with model control group,APTT in Taohong Siwu decoction low-dose,medium-dose and high-dose groups were significantly prolonged 1d to 7d after operation(P<0.05),FIB value of Taohong Siwu decoction medium and high dose groups decreased significantly from 1d to 7d after operation(P<0.05),the FIB value of Taohong Siwu decoction low-dose group was significantly decreased from 2d to 7d after surgery(P<0.05);Compared with papaverine hydrochloride injection group,APTT in Taohong Siwu decoction medium dose group was significantly prolonged 2d to 7d after surgery(P<0.05),APTT of Taohong Siwu decoction high-dose group was significantly prolonged on 1d to 7d after operation(P<0.05).FIB in Taohong Siwu decoction medium and high dose groups decreased significantly 1d to 7d after operation(P<0.05);Compared with the blank control group,the expression concentrations of PI3K,Akt and mTOR in serum of the model control group were significantly increased from 1d to 7d after surgery(P<0.05);Compared with the model control group,the expression levels of PI3K,Akt and mTOR in serum were significantly increased in the low dose group of Taohong Siwu decoction and Papaverine Hydrochloride Injection group on postoperative 7 days(P<0.05),Taohong Siwu decoction high-dose group was significantly increased from 1d to 7d after surgery(P<0.05),the expression concentrations of PI3K and Akt in Taohong Siwu decoction medium dose group were significantly increased from 2d to 7d after operation(P<0.05),mTOR expression levels were significantly increased from 3d to 7d after operation(P<0.05);Compared with papaverine hydrochloride injection group,the expression concentrations of PI3K,Akt and mTOR in serum of Taohong Siwu decoction medium dose group were significantly increased from 3d to 7d after operation(P<0.05),the expression concentrations of PI3K and mTOR in Taohong Siwu decoction high-dose group were significantly increased from 1d to 7d after operation(P<0.05),and the expression concentration of Akt increased significantly from 3d to 7d after operation(P<0.05).Conclusion:The Taohong Siwu decoction can improve the coagulation function of rabbit femoral artery anastomosis,prevent thrombosis,activate PI3K/Akt/mTOR signaling pathway,promote angiogenesis,and improve tissue ischemia after artery anastomosis.

Quantum Remote State Preparation Based on Quantum Network Coding

As an innovative theory and technology,quantum network coding has become the research hotspot in quantum network communications.In this paper,a quantum remote state preparation scheme based on quantum network coding is proposed.Comparing with the general quantum remote state preparation schemes,our proposed scheme brings an arbitrary unknown quantum state finally prepared remotely through the quantum network,by designing the appropriate encoding and decoding steps for quantum network coding.What is worth mentioning,from the network model,this scheme is built on the quantum k-pair network which is the expansion of the typical bottleneck network—butterfly network.Accordingly,it can be treated as an efficient quantum network preparation scheme due to the characteristics of network coding,and it also makes the proposed scheme more applicable to the large-scale quantum networks.In addition,the fact of an arbitrary unknown quantum state remotely prepared means that the senders do not need to know the desired quantum state.Thus,the security of the proposed scheme is higher.Moreover,this scheme can always achieve the success probability of 1 and 1-max flow of value k.Thus,the communication efficiency of the proposed scheme is higher.Therefore,the proposed scheme turns out to be practicable,secure and efficient,which helps to effectively enrich the theory of quantum remote state preparation.

Dynamic Ring-chain Equilibrium of Nucleophilic Thiol-yne "Click" Polyaddition for Recyclable Poly(dithioacetal)s

We report a dynamic polymerization system based on the reversible nucleophilic Michael polyaddition of activated alkynes and dithiols.Four poly(dithioacetal)s(P1-P4)were prepared via the base-catalyzed thiol-yne"click"polyaddition of two dithiols(1,4-butanedithiol(4S)and 1,5-pentanedithiol(5S))and two alkynones(3-butyn-2-one(Y1)and 1-phenyl-2-propyn-1-one(Y2))at high concentrations.We systematically investigated the base-catalyzed polymerization of 4S and Y1(for polymer PI)under different conditions,and found that this polymerization was a highly concentration-dependent dynamic system:polymer PI was formed at high concentration,while seven-membered dithioacetal,1-(1,3-dithiepan-2-yl)propan-2-one(C1),was obtained at low concentration.The polymerization of 4S and Y2(for polymer P4)displayed similar polymerization behavior,generating 2-(1,3-dithiepan-2-yl)-1-phenylethanone(C4)at low concentration.On the contrary,polymer P2(from Y1 and 5S)was exclusively obtained with no formation of eight-membered dithioacetal.The polymerizations of Y1 with 1,2-ethanedithiol(2S)and 1,3-dimercaptopropane(3S)only afforded corresponding five-and six-membered dithioacetals,1-(1,3-dithiolan-2-yl)propan-2-one(C2)and 1-(1,3-dithian-2-yl)propan-2-one(C3).This dynamic behavior of PI and P4 was attributed to the concentration-dependent retro-Michael addition reaction between a thiol and a β-sulfido-α,β-unsaturated carbonyl compound catalyzed by bases.Furthermore,polymers P1 and P4 could be depolymerized into Cl and C4 in yields of 58% and 95%,respectively.The ring-opening polymerization of Cl at high concentration could successfully regenerate polymer PI.Thus,a new type of closed-loop recyclable poly(dithioacetal)s was developed.

Special Issue:Celebrating the 70th Anniversary of the Establishment of Polymer Program at Peking University

The polymer program at Peking University(PKU)was founded by Prof.Xinde Feng in 1953,and is the earliest polymer educational and research organization in China.Nine undergraduates specialized in polymer chemistry,the earliest in China,graduated in 1955.Postgraduate education in polymer chemistry at PKU was initiated by Prof.Feng,from 1953 to 1965,he supervised 13 postgraduate students.In 1978 when China resumed Regulations on Academic Degrees,Prof.Feng recruited 8 threeyear master's degree students.Since then,PKU polymer program,under the leadership of Prof.Feng,has entered into a rapid development stage of postgraduate training.The first doctor of science degree in polymer chemistry was awarded in 1984,and two post-doctoral fellows joined PKU polymer program in 1989.

中国高分子合成化学的研究与发展动态

高分子合成化学是主要研究高分子量化合物的分子设计、合成和改性等内容的科学,它为人类社会进步、生活水平提高及国家安全提供了必不可少的物质保障.中华人民共和国成立70年来,中国学者为推动此领域的发展作出了积极贡献,在设计合成新单体和聚合物、研发高效且环境友好新型催化剂、发展新的聚合反应、探索新的聚合方法、优化合成路径、开发聚合新工艺、发现新的结构与性能等方面取得了一系列重要的创新成果.本文总结和评述了中国高分子合成化学的研究与动态,并展望了不同聚合反应、高分子拓扑结构控制以及生物质来源单体的设计、合成与聚合等的未来发展.

Ring-opening Polymerization of 2-Oxabicyclo[2.2.2]octan-3-one and the Influence of Stereochemistry on the Thermal Properties of the Polyesters

Polyesters with cyclic structures in the main chain typically possess superior mechanical and thermal properties together with chemical recyclability.Ring-opening polymerization(ROP)of bridged or fused bicyclic lactones is a simple,and in most cases controlled method to synthesize polyesters with alicyclic moieties in the polymer backbone.The stereochemistry of the alicyclic structures has a great effect on the polymer properties,which can be regulated by varying the polymerization conditions.Here,we report a systematic investigation on the ROP of 2-oxabicyclo[2.2.2]octan-3-one([2.2.2]VL)under different conditions.When initiated byn-butyl lithium(n-BuLi)or catalyzed by trifluoromethanesulfonic acid(TfOH)in the presence of benzyl alcohol,P[2.2.2]VLs containing all cis^(-1),4 disubstituted cyclohexane ring were obtained.However,P[2.2.2]VLs initiated by sodium methoxide(MeONa)or catalyzed by organic superbase contained both cis and trans isomeric structural units.The cis to trans transformation mechanism under these conditions was manifested,and the effect of stereochemical variations on the properties ofP[2.2.2]VLwas revealed.The stereoregularP[2.2.2]VLs,bothcisandtrans,exhibited higher crystallinity and melting temperatures(Tm)than those of the stereoirregular isomers.Finally,the degradation of P[2.2.2]VL with acid at high temperature could recover 3-cyclohexenecarboxylic acid.

Arctic warming trends and their uncertainties based on surface temperature reconstruction under different sea ice extent scenarios

IPCC AR6 states that the neglect of recent rapid warming in the Arctic generally leads to an underestimate of global warming trends.In this study,by reconstructing the surface temperature(ST)datasets in the Arctic under different sea ice extent scenarios(Imax and Imin),we respectively evaluated the annual and seasonal warming trends and their uncertainties from 1900 to 2020.The results show that the reconstructed datasets have a good representation of the ST change trends in the Arctic.In 1900e2020,the annual warming trends in the Arctic(0.17±0.031 and 0.14±0.025℃ per decade under the Imax and Imin reconstruction,respectively)are roughly 1.6e1.8 times the global mean warming trends(0.10±0.008 and 0.09±0.008℃ per decade).While in 1979e2020,the Arctic warming trends(0.66±0.100 and 0.55±0.080℃ per decade)increase to 3.1e3.5 times of the global warming trend(0.19±0.023 and 0.18±0.023℃ per decade)for Imax and Imin,respectively,indicating that the Arctic amplification effect has been significantly enhancing in recent decades.Although the seasonal warming trends are closely related to cloud feedback mechanisms,atmospheric circulation,and ocean circulation,they are not sensitive to the different reconstruction scenarios.

PREFACE

This special issue is dedicated to Prof.Shi-Lin Yang on his 100th anniversary of birth.Contributions from many ofhis students and the researchers around the world have been collected as a tribute to his memory.

Special Issue:In Memory of Professor Fosong Wang

Professor Fosong Wang was a leading polymer chemist and made great contributions in polymer science including synthetic rubber,stereospecific polymerization,conjugated polymers and biodegradable polymers.He was also a highly respected educator in the field of polymer.He was not only a professor,a mentor,but also an academic father to many students.

PREFACE

We are delighted to pres ent this special themed topic of Chinese Journal of Polymer Science(CJPS)devoted to the recent advances in reversible deactivation radical polymerization(RDRP).RDRP has been widely recognized as one of the most important synthetic methods for polymers,allowing access to well-defined polymeric materials with predictable molecular weight,controlled dispersity,and tailor-made architecture.