Background:Colorectal cancer is a major global health concern,exacerbated by tumor necrosis factor-alpha(TNF-α)and its role in inflammation,with the effects of Mitotic Arrest Deficient 2 Like 2(MAD2L2)in this context...Background:Colorectal cancer is a major global health concern,exacerbated by tumor necrosis factor-alpha(TNF-α)and its role in inflammation,with the effects of Mitotic Arrest Deficient 2 Like 2(MAD2L2)in this context still unclear.Methods:The colorectal carcinoma cell lines HCT116 and SW620 were exposed to TNF-αfor a period of 24 h to instigate an inflammatory response.Subsequent assessments were conducted to measure the expression of inflammatory cytokines,the activity within the p38 mitogen-activated protein kinase(p38 MAPK)and Phosphoinositide 3-Kinase/AKT Serine/Threonine Kinase pathway(PI3K/AKT)signaling cascades.Transcriptome sequencing and subsequent integrative analysis with the Cancer Genome Atlas(TCGA)program database revealed a significant downregulation of the key factor MAD2L2.Enhancement of MAD2L2 expression was facilitated via lentiviral vector-mediated transfection.The influence of this overexpression on TNF-α-prompted inflammation,intracellular signaling pathways,and the migratory and invasive behaviors of the colorectal cancer cells was then scrutinized.Results:TNF-αtreatment significantly increased the expression of Interleukin-1 beta(IL-1β)and Interleukin-6(IL-6),activated the MAPK p38 and PI3K/AKT signaling pathways,and enhanced cell migration and invasion.A decrease in MAD2L2 expression was observed following TNF-αtreatment.However,overexpression of MAD2L2 reversed the effects of TNF-α,reducing IL-1βand IL-6 levels,attenuating PI3K/AKT pathway activation,and inhibiting cell migration and invasion.Conclusions:Overexpression of MAD2L2 attenuates the pro-inflammatory effects of TNF-α,suggesting that MAD2L2 plays a protective role against TNF-α-induced migration and invasion of colorectal carcinoma cells.Therefore,MAD2L2 holds potential as a therapeutic target in the treatment of colorectal cancer.展开更多
Background:Colon adenocarcinoma(COAD)is the second leading cause of cancer death worldwide thus,identification of COAD biomarkers is critical.Mitotic Arrest Deficient 2 Like 2(MAD2L2)is a key factor in mammalian DNA d...Background:Colon adenocarcinoma(COAD)is the second leading cause of cancer death worldwide thus,identification of COAD biomarkers is critical.Mitotic Arrest Deficient 2 Like 2(MAD2L2)is a key factor in mammalian DNA damage repair and is highly expressed in many malignant tumors.This is a comprehensive study of MAD2L2 expression,its diagnostic value,prognostic analysis,potential biological function,and impact on the immune system of patients with COAD.Methods:Gene expression,clinical relevance,prognostic analysis,diagnostic value,GO/KEGG cluster analysis,data obtained from TCGA,and bioinformatics statistical analysis were performed using the R package.Immune responses to MAD2L2 expression in COAD were analyzed using TIMER.The expression of MAD2L2 in HCT116 cells induced by the inflammatory factor TNF-αwas detected using Western blot.Results:Our results underscore the clinical diagnostic value and potential biological significance of MAD2L2 in patients with COAD.A high level of MAD2L2 expression has been found in COAD and correlated with tumor status and colon polyps.ROC curve analysis showed that MAD2L2 expression has high diagnostic value in COAD.Analysis of immune infiltration results showed that MAD2L2 expression was positively correlated with neutrophil levels.The western blot results demonstrated that MAD2L2 was dose-dependently present with TNF-α.GO/KEGG revealed that MAD2L2 overexpressed and coexpressed genes were mostly involved in biological functions,including hypoxia response,response to reduced oxygen levels,mitochondrial translation elongation,and other processes.Conclusion:MAD2L2 as a new COAD biomarker contributes to our understanding of how alterations in gene expression and the immunological environment contribute to the development of colon cancer.Following further investigation,MAD2L2 may prove to be a viable target factor for clinical diagnosis and therapy of COAD.展开更多
BACKGROUND Early diabetic nephropathy(DN)is a complication of diabetes mellitus.It mainly affects kidney microvessels and glomerular function,and its timely and effective treatment is critical for early DN.However,the...BACKGROUND Early diabetic nephropathy(DN)is a complication of diabetes mellitus.It mainly affects kidney microvessels and glomerular function,and its timely and effective treatment is critical for early DN.However,the effects of treatments comprising simple Western medicine are not optimal.With the promotion and implementation of integrated Chinese and western medicine treatments,remarkable results have been achieved for many diseases.To this end,we explored the clinical efficacy of integrated traditional Chinese and western medicines for the treatment of early DN.AIM To investigate the effect of sitagliptin tablets combined with Yiqi yangyin huoxue decoction on clinical efficacy and hemorheology in patients with early DN.METHODS Through a retrospective analysis,123 patients with early DN were admitted to the endocrinology clinic of the Changzhou NO.7 People’s Hospital from January 2021 to October 2022 and were selected as study subjects.After rigorous screening,100 patients with early DN were enrolled.The control group(CG,n=50)and the observation group(OG,n=50)were divided according to the treatment method.The CG were treated with sitagliptin,and the OG were treated with sitagliptin plus the Yiqi yangyin huoxue decoction.Both groups were treated for 3 mo.For both groups,the baseline data and clinical efficacy were compared,and changes in blood glucose levels,lipid levels,renal function,and hematological indicators before(T0)and after(T1)treatment were assessed.RESULTS The total effective rate for the OG was 94.00%and that of the CG was 80.00%(P<0.05).After treatment(T1),the levels of fasting blood glucose,2 h postprandial glucose,total cholesterol,triacylglycerol,and low-density lipoprotein cholesterol in OG patients were obviously lower than those in the CG(P<0.05),and cystatin C,homocysteine,urinary microalbumin,and blood creatinine values in OG patients were also obviously lower than those in the CG(P<0.05);erythrocyte deposition,plasma viscosity,whole blood high shear viscosity,and whole blood low shear viscosity were markedly lower in OG patients than in the CG(P<0.05).CONCLUSION Sitagliptin combined with Yiqi yangyin huoxue decoction has a remarkable effect when used to treat patients with early DN.Further,it is helpful in improving hemorheological indices and controlling disease progression.展开更多
Early fault warning for nuclear power machinery is conducive to timely troubleshooting and reductions in safety risks and unnecessary costs. This paper presents a novel intelligent fault prediction method, integrated ...Early fault warning for nuclear power machinery is conducive to timely troubleshooting and reductions in safety risks and unnecessary costs. This paper presents a novel intelligent fault prediction method, integrated probabilistic principal component analysis(PPCA), multi-resolution wavelet analysis, Bayesian inference, and RNN model for nuclear power machinery that consider data uncertainty and chaotic time series. After denoising the source data, the Bayesian PPCA method is employed for dimensional reduction to obtain a refined data group. A recurrent neural network(RNN) prediction model is constructed, and a Bayesian statistical inference approach is developed to quantitatively assess the prediction reliability of the model. By modeling and analyzing the data collected on the steam turbine and components of a nuclear power plant, the results of the goodness of fit, mean square error distribution, and Bayesian confidence indicate that the proposed RNN model can implement early warning in the fault creep period. The accuracy and reliability of the proposed model are quantitatively verified.展开更多
AIM: To evaluate the efficacy of the improvedthrombospondin mimetic peptide ABT-898 in a murine model of ulcerative colitis. METHODS: The dextran sodium sulfate(DSS) was used for the induction of colitis in both TSP-1...AIM: To evaluate the efficacy of the improvedthrombospondin mimetic peptide ABT-898 in a murine model of ulcerative colitis. METHODS: The dextran sodium sulfate(DSS) was used for the induction of colitis in both TSP-1 deficient(TSP-1-/-) and wild type(WT) mice during 7 d. While mice were receiving the DSS dissolved in the drinking water, the ABT-898 peptide was dissolved in sterile 5% glucose solution and delivered using mini pumps subcutaneously implanted. Plasma samples were analyzed for interleukin(IL)-6 by ELISA assay and colonic tissues were harvested, fixed and processed for histological evaluation. Immunohistochemistry using antibodies for the detection of CD31 and MECA in endothelial cells was performed. Inflammation was graded in colonic sections and the number of microvessels in each lesion was assessed. Activation of signal transducer and activator of transcription 3(STAT3) in colonic samples was quantified by immunohistochemistry and Western blotting using antibodies against total STAT3 and phosphorylated STAT3(p STAT3)(Ser727).RESULTS: Treatment with ABT-898 considerably diminished the inflammatory response in WT and TSP-1-/- mice(P < 0.0001 in both groups vs control). Identification of blood vessels highlighted by CD31/MECA immunohistochemistry, showed significantly reduced vessel counts in colitic lesions of WT and TSP-1-/- mice treated with ABT898(TSP-1-/- controls/TSP-1-/- treated, P = 0.0002; WT controls/WT treated, P = 0.0005). Consistently, IL-6 was significantly diminished in plasma samples of TSP-1-/- and WT treated with the peptide when compared to the control mice(P = 0.0002 and P = 0.0148, respectively). p STAT3 positive cells were quantified in WT and TSP-1-/- treated with ABT-898. A significant decrease in positive cells for p STAT3 was observed in treated mice(TSP-1-/- controls/TSP-1-/- treated, P = 0.0089; WT/WT treated, P = 0.0110). These results were confirmedby Western blotting analyses showing lower levels of p STAT3 in colitic lesions from mice treated with the peptide ABT-898.CONCLUSION: These findings indicate that the new peptide ABT-898 ameliorates inflammation and angiogenesis and might be a therapeutic alternative in IBD and inflammatory diseases.展开更多
The ring opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) initiated by single component of tris(2,6-di-tert-butyl-4-methylphenoxo) lanthanide (Ln(OAr)(3)) is reported. The initiators are highly activ...The ring opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) initiated by single component of tris(2,6-di-tert-butyl-4-methylphenoxo) lanthanide (Ln(OAr)(3)) is reported. The initiators are highly active to the polymerization and give high molecular weight polymers. (HNMR)-H-1 spectra and DSC measurement suggest the polymerization is free of decarboxylation. Mechanism study shows that the monomer insertion is via the break of acyl-oxygen bond of DTC.展开更多
At the 63rd Venice International ,Film Festival concluded on September 9, 2006, the Chinese film ＂Still Life＂ directed by Jia Zhangke won the Golden Lion Award as the best film.Jia＇s documentary ＂The East＂ also w...At the 63rd Venice International ,Film Festival concluded on September 9, 2006, the Chinese film ＂Still Life＂ directed by Jia Zhangke won the Golden Lion Award as the best film.Jia＇s documentary ＂The East＂ also won the Italian Documentaries Association Award and the ＂Open 2006＂ Award.展开更多
The utilization of carbon dioxide(CO_(2))as a C1 feedstock is consistently attractive,especially in the preparation of sustainable polymeric materials.In this contribution,a terpolymer of CO_(2),1,3-butadiene(BD)and e...The utilization of carbon dioxide(CO_(2))as a C1 feedstock is consistently attractive,especially in the preparation of sustainable polymeric materials.In this contribution,a terpolymer of CO_(2),1,3-butadiene(BD)and epoxide is synthesized by scandium triflate catalyzed cationic ring-opening copolymerization ofα-ethylidene-δ-vinyl-δ-valerolactone(EVL),an intermediate derived from CO_(2)and BD,with epoxides.The obtained terpolymer with a CO_(2)content of 22 mol%has a number-average molecular weight(M_(n))up to 7.8 kg/mol and a dispersity(Đ)of 2.4.The reactivity ratios of EVL and cyclohexene oxide(CHO)are determined as 0.01 and 1.07,respectively,suggesting random characteristic of the terpolymer.The preserved C=C double bonds from BD allow for the further modification of the terpolymer by photoinitiated crosslinking.The yielded networks are fluorescent and degradable.This method offers enhanced versatility to the synthesis and additional functionalization of CO_(2)-based polymers.展开更多
Light-emitting diode(LED)irradiation can affect postharvest vegetable and fruit shelf life and nutritional quality.In this study,11 kinds of glucosinolates(GLS)and 6 types of GLS breakdown products were identified in ...Light-emitting diode(LED)irradiation can affect postharvest vegetable and fruit shelf life and nutritional quality.In this study,11 kinds of glucosinolates(GLS)and 6 types of GLS breakdown products were identified in cabbage leaves.To investigate the effects of LED irradiation on quality and GLS metabolism,postharvest cabbage was irradiated with 25μmol/(m2·s)green LED(GL)light at room temperature for 12 d.The dark condition and natural light were used as controls.GL irradiation inhibited the respiration rate and the accumulation of malondialdehyde,and maintained higher cabbage sensory score,chlorophyll content,and antioxidant enzyme activities,thus extending its postharvest shelf life.Additionally,GL irradiation promoted GLS profile accumulation,including glucoraphanin,glucoiberin,gluconapin,gluconasturtiin,glucobrassicin,and sinigrin,which could have resulted from upregulated expression of the transcription factors MYB28 and MYB51,and the key genes involved in GLS biosynthesis(CYP83A1,CYP83B1,ST5b,and UGT74B1).Furthermore,GLS degradation was promoted by this treatment during the late stage of shelf life,as higher myrosinase activity and relative MYR and ESM expression levels were found in treated cabbage leaves,resulting in higher isothiocyanate(ITC)and indole-3-carbinol contents after day 6.Therefore,GL irradiation was beneficial for cabbage preservation.展开更多
Polyurethanes consisting of tri-functional homopolymer of hexamethylene diisocyanate （tri-HDI） and polyethylene glycol （PEG） are synthesized, in which photo-reversible coumarin moieties act as pendant groups. Acco...Polyurethanes consisting of tri-functional homopolymer of hexamethylene diisocyanate （tri-HDI） and polyethylene glycol （PEG） are synthesized, in which photo-reversible coumarin moieties act as pendant groups. Accordingly, the polyurethanes can be repeatedly self-healed under UV lights at room temperature by taking advantages of the photodimerization and photocleavage habits of coumarin. Molecular weight of the soft segment, PEG, is found to be closely related to the healing performance of the polyurethanes. Lower molecular weight PEG that corresponds to higher initial coumarin concentration in the polymer is critical for obtaining higher healing efficiency in the case of the first healing action. Nevertheless, it does not guarantee high reversibility of the photo-remendability during the repeated healing events. In contrast, the polyurethane with moderate molecular weight PEG has achieved balanced performance. Reaction kinetics is less important for the healing effect.展开更多
Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable s...Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable synthetic technique for functional poly(ε-caprolactone)(PCL) via Janus polymerization, which comprises cationic ring-opening copolymerization (ROP) of ε-caprolactone (CL) with 3,3-bis(chloromethyl)oxacyclobutane (CO) and (coordinated) anionic ROP of CL at a single propagating chain by rare earth metal triflates (RE(OTf)3)and propylene oxide, thus generating block copolymers in one step. The compositions of the copolymers of poly(CLb-(CL-r-CO)) can be modulated by various RE(OTf)3. Scandium triflate catalyzes Janus polymerization to yield the copolymers containing the highest CO contents among all the RE(OTf)3 catalysts used with complete conversion of CL. The chlorine in CO repeating units is ready to be transferred into azide group which affords the modification sites to react with 9-ethynyl-9-fluorenol and mPEG-alkyne, respectively, via copper(I)-catalyzed azide-alkyne cycloaddition reaction with quantitative conversions of azides, as confirmed by FTIR analyses. According to NMR and SEC analyses, copolymers (PCC-g-PEG) bearing a homo-PCL block and a PEG-grafted block of poly(CO-co-CL) demonstrate well-defined chemical structures. The investigations on thermal properties reveal the strong phase separation between PCL and PEG blocks. The amphiphilic PCC-g-PEG is able to sei住assemble into micelles in aqueous solution while cylindrical and lamellar morphologies are observed in bulk. We provide an efficient protocol to synthesize functional PCL combining onestep Janus polymerization and precise post-polymerization click reaction.展开更多
Amphiphilic block copolymers poly(ethylene glycol)-block-poly(N-3-(methylthio)propyl glycine)(PEGb-PMeSPG)were synthesized via ring-opening polymerization of N-3-(methylthio)propyl glycine Nthiocarboxyanhydride(MeSPG-...Amphiphilic block copolymers poly(ethylene glycol)-block-poly(N-3-(methylthio)propyl glycine)(PEGb-PMeSPG)were synthesized via ring-opening polymerization of N-3-(methylthio)propyl glycine Nthiocarboxyanhydride(MeSPG-NTA)initiated by amino-terminated PEG.The self-assemblies of three PEG-b-PMeSPG copolymers with different PMeSPG block lengths were first prepared by nanoprecipitation method using THF and DMF,respectively,as the organic solvent,and their morphologies were studied by Cryo-EM and DLS.To prepare polymersomes loaded with glucose oxidase(GOx),double emulsion method followed by extrusion treatment was employed.The oxidation-responsive disruption of polymersomes was achieved upon the introduction of glucose because of the oxidants generated insitu by GOx/glucose.展开更多
Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxid...Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including(1) fast cationic polymerization with slow anionic one,(2) fast anionic polymerization with dormant cationic one, and(3)reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory(DFT)calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results.展开更多
To substantially prevent electromagnetic threatens,microwave absorbing materials(MAMs)are required to eliminate surplus electromagnetic waves.As a typical MAM,Fe_(3)O_(4) particles with complex permittivity and permea...To substantially prevent electromagnetic threatens,microwave absorbing materials(MAMs)are required to eliminate surplus electromagnetic waves.As a typical MAM,Fe_(3)O_(4) particles with complex permittivity and permeability have been widely applied due to the coexistence of magnetic loss and dielectric loss.However,the necessary high mass fraction significantly limited its applications,thus Fe_(3)O_(4) nanostructures have been extensively investigated to overcome this problem.In this work,uniform Fe_(3)O_(4) nanobelts were prepared by electrospinning and two-step thermal treatment.By controlling the composition and viscosity of the electrospinning precursor solution,Fe_(3)O_(4) nanobelts with tunable lateral sizes(200 nme1 mm)were obtained.The samples with low content(only 16.7 wt%)Fe_(3)O_(4) exhibited wide maximum effective absorbing bandwidths(EAB)over 3 GHz,and Fe_(3)O_(4) nanobelts with smaller lateral sizes showed a maximum EAB of 4.93 GHz.Meanwhile,Fe_(3)O_(4) nanobelts with smaller lateral sizes presented superior reflection loss properties,the lowest reflection loss reached-53.93 dB at 10.10 GHz,while the maximum EAB was up to 2.98 GHz.The excellent microwave reflection loss of Fe_(3)O_(4) nanobelts was contributed to the enhanced synergistic effect of magnetic loss,dielectric loss,and impedance matching,originated from the hierarchically cross-linked networks and shape anisotropies.This study could broaden the practical applications of magnetic absorbers,and provided an approach for the development of shape anisotropic magnetic materials.展开更多
The synthesis of block copolymers of poly(tetrahydrofuran)-b-poly(α-amino acid)(PTHF-b-PAA)is challenging since it is difficult to combine the two blocks produced via different/conflicting ring-opening polymerization...The synthesis of block copolymers of poly(tetrahydrofuran)-b-poly(α-amino acid)(PTHF-b-PAA)is challenging since it is difficult to combine the two blocks produced via different/conflicting ring-opening polymerization(ROP)mechanisms.In this contribution,the cationic ROP of THF is catalyzed by rare-earth triflate[RE(OTf)3]and terminated by 2-(t-butyloxycarbonyl-amino)ethanol(BAE).After the deprotection of t-butyloxycarbonyl(Boc)group,the chain end of PTHF is quantitatively changed to amino group which thereafter initiates the nucleophilic ROP ofα-amino acid N-thiocarboxyanhydrides(NTAs).Both polymerizations are well controlled,generating PTHF and PAA segments with designable molecular weights(MWs).PTHF-b-polylysine(PTHF-b-PLys)and PTHF-b-polysarcosine(PTHF-b-PSar)are obtained with MWs between 8.6 and 28.7 kg/mol.The above amphiphilic diblock copolymers form micelles in water.PTHF40-b-PSar32 acts as a surfactant to stabilize oil-in-water emulsions.Both segments of PTHF-b-PAA are biocompatible and promising in the biomedical application.展开更多
A series of donor-acceptor oligomer OBTThn （n = 1- 7） and polymer PBTThl and PBTTh2 composed of al- ternative 2,1,3-benzothiadiazole and 3-hexylthiophene have been designed and synthesized for the purpose of in- ves...A series of donor-acceptor oligomer OBTThn （n = 1- 7） and polymer PBTThl and PBTTh2 composed of al- ternative 2,1,3-benzothiadiazole and 3-hexylthiophene have been designed and synthesized for the purpose of in- vestigation on the effect of chain length and side-chain regioregularity on their basic properties and photovoltaic performance. In the OBTThn oligomers and PBTThl polymer, all the hexyl side chains on thienyl units orient to- ward the same direction. Upon elongation of the chain length, the intramolecular charge transfer （ICT） absorption band in solution gradually redshifts from 398 nm for OBTThl to 505 nm for OBTThT, then to 512 nm for PBTThl polymer. Meanwhile, the HOMO energy level increases from -5.45 eV （OBTTh0 to -5.08 eV （OBTThT） and -5.09 eV （PBTThl）, and the LUMO energy level decreases from -3.11 eV （OBTTh0 to -3.30 eV （OBTThT） and -3.33 eV （PBTThl）, thus giving a smaller and smaller energy bandgap for higher oligomers and polymers. Theo- retical calculation suggests straight line-like backbone geometry for this series of oligomers and polymer. On the other hand, polymer PBTTh2 possesses a different side-chain regioregularity, in which every two neighbor hexyl side chains are arranged in different orienting direction. It is theoretically suggested to have curved line-like back- bone geometry. In solution, it shows similar photophysical and electrochemical properties as PBTThl. However in film state, it displays a less redshift in the ICT band as refer to that in solution than PBTThl. In combination with [6,6]-phenyl-C61-butyric acid methyl ester （PC61BM）, these oligomers and polymers were used as donor material to fabricate organic bulk heterojunction solar cells. Again, chain length-dependent device photovoltaic performance was observed. The device based on OBTTh4 showed a power conversion efficiency of 0.16%, while it increased to 0.36% and 0.49% for the devices based on OBTTh6 and PBTThb respectively. However, the side-chain regio- regularity has less influence on the device photovoltaic output since the device based on PBTTh~ displayed an effi- ciency of 0.52%, comparable to that of PBTThl.展开更多
Janus polymerization consists of anionic and cationic ring opening polymerizations(AROP and CROP)at the two ends of a single propagating polymer chain,followed by a self-triggered chain extension generating multiblock...Janus polymerization consists of anionic and cationic ring opening polymerizations(AROP and CROP)at the two ends of a single propagating polymer chain,followed by a self-triggered chain extension generating multiblock copolymers(MBCPs)in one step.In the contribution,Janus polymerization by Tm(OTf)_(3) or Er(OTf)_(3) catalyst with an epoxy initiator is applied to synthesize MBCPs of semi-crystalline poly(ε-caprolactone)(PCL)blocks from coordinated AROP and poly(1,3-dioxolane-co-ε-caprolactone)(P(DO-co-CL))blocks from CROP of DO with CL.Meanwhile,amorphous random copolymers[P(DO-r-CL)]are synthesized as control by employing other rare earth triflates[RE(OTf)_(3),RE=Y,Nd,Gd and Lu]as catalysts or in the absence of an initiator via CROP.On account of the distinguishable chemical structures and thermal properties between Janus MBCPs and cationic random copolymers,Janus features are confirmed including the CROP and AROP at a single propagating chain.The resultant amphiphilic copolymers self-assemble to nanoparticles in aqueous solution with designable diameters with the corresponding ratios of hydrophilic and hydrophobic seg-ments.MBCPs exhibit good shape memory properties with appropriate deformation temperature close to human body's,providing a prospect on the applications in biomedical devices.展开更多
In comparing with traditional polymer degradation toward unknown or unvalued products(i.e.,downcycling),new methods to degrade polymers into monomers or high-value-added materials(i.e.,upcycling)are preferable for sus...In comparing with traditional polymer degradation toward unknown or unvalued products(i.e.,downcycling),new methods to degrade polymers into monomers or high-value-added materials(i.e.,upcycling)are preferable for sustainable developments.In this work,CO_(2)-based linear and cross-linked unsaturated polyesters,that is,poly(alkynoate)s,were successfully degraded by benzamidine into diols and high-value-added pyrimidone or imidazolone derivatives through controlled reaction conditions.The degradation process could be visualized under UV light via gradually increased luminescent intensity of the reaction mixtures and fluorescence patterns could be generated through microcontact printing of the stamp on the thin films of poly(alkynoate)s.Moreover,the pyrimidone derivatives could be applied in bioimaging and inhibiting bacteria,and the imidazolone derivatives could be used for the detection and recovery of gold(III)ions from electronic waste and serve as the fluorescent sensor to detect in situ-generated amines from food spoilage.Thus,this work presents a visualized and high value productselective degradation to solve the end-of-life issue of polymers.展开更多
基金supported by the Ningxia Hui Autonomous Region key research and development programs(Grant No.2021BEG03084)the National Natural Science Foundation of China(Grant No.31660336).
文摘Background:Colorectal cancer is a major global health concern,exacerbated by tumor necrosis factor-alpha(TNF-α)and its role in inflammation,with the effects of Mitotic Arrest Deficient 2 Like 2(MAD2L2)in this context still unclear.Methods:The colorectal carcinoma cell lines HCT116 and SW620 were exposed to TNF-αfor a period of 24 h to instigate an inflammatory response.Subsequent assessments were conducted to measure the expression of inflammatory cytokines,the activity within the p38 mitogen-activated protein kinase(p38 MAPK)and Phosphoinositide 3-Kinase/AKT Serine/Threonine Kinase pathway(PI3K/AKT)signaling cascades.Transcriptome sequencing and subsequent integrative analysis with the Cancer Genome Atlas(TCGA)program database revealed a significant downregulation of the key factor MAD2L2.Enhancement of MAD2L2 expression was facilitated via lentiviral vector-mediated transfection.The influence of this overexpression on TNF-α-prompted inflammation,intracellular signaling pathways,and the migratory and invasive behaviors of the colorectal cancer cells was then scrutinized.Results:TNF-αtreatment significantly increased the expression of Interleukin-1 beta(IL-1β)and Interleukin-6(IL-6),activated the MAPK p38 and PI3K/AKT signaling pathways,and enhanced cell migration and invasion.A decrease in MAD2L2 expression was observed following TNF-αtreatment.However,overexpression of MAD2L2 reversed the effects of TNF-α,reducing IL-1βand IL-6 levels,attenuating PI3K/AKT pathway activation,and inhibiting cell migration and invasion.Conclusions:Overexpression of MAD2L2 attenuates the pro-inflammatory effects of TNF-α,suggesting that MAD2L2 plays a protective role against TNF-α-induced migration and invasion of colorectal carcinoma cells.Therefore,MAD2L2 holds potential as a therapeutic target in the treatment of colorectal cancer.
基金supported by the Ningxia Hui Autonomous Region Key Research and Development Program(Grant No.2021BEG03084).
文摘Background:Colon adenocarcinoma(COAD)is the second leading cause of cancer death worldwide thus,identification of COAD biomarkers is critical.Mitotic Arrest Deficient 2 Like 2(MAD2L2)is a key factor in mammalian DNA damage repair and is highly expressed in many malignant tumors.This is a comprehensive study of MAD2L2 expression,its diagnostic value,prognostic analysis,potential biological function,and impact on the immune system of patients with COAD.Methods:Gene expression,clinical relevance,prognostic analysis,diagnostic value,GO/KEGG cluster analysis,data obtained from TCGA,and bioinformatics statistical analysis were performed using the R package.Immune responses to MAD2L2 expression in COAD were analyzed using TIMER.The expression of MAD2L2 in HCT116 cells induced by the inflammatory factor TNF-αwas detected using Western blot.Results:Our results underscore the clinical diagnostic value and potential biological significance of MAD2L2 in patients with COAD.A high level of MAD2L2 expression has been found in COAD and correlated with tumor status and colon polyps.ROC curve analysis showed that MAD2L2 expression has high diagnostic value in COAD.Analysis of immune infiltration results showed that MAD2L2 expression was positively correlated with neutrophil levels.The western blot results demonstrated that MAD2L2 was dose-dependently present with TNF-α.GO/KEGG revealed that MAD2L2 overexpressed and coexpressed genes were mostly involved in biological functions,including hypoxia response,response to reduced oxygen levels,mitochondrial translation elongation,and other processes.Conclusion:MAD2L2 as a new COAD biomarker contributes to our understanding of how alterations in gene expression and the immunological environment contribute to the development of colon cancer.Following further investigation,MAD2L2 may prove to be a viable target factor for clinical diagnosis and therapy of COAD.
文摘BACKGROUND Early diabetic nephropathy(DN)is a complication of diabetes mellitus.It mainly affects kidney microvessels and glomerular function,and its timely and effective treatment is critical for early DN.However,the effects of treatments comprising simple Western medicine are not optimal.With the promotion and implementation of integrated Chinese and western medicine treatments,remarkable results have been achieved for many diseases.To this end,we explored the clinical efficacy of integrated traditional Chinese and western medicines for the treatment of early DN.AIM To investigate the effect of sitagliptin tablets combined with Yiqi yangyin huoxue decoction on clinical efficacy and hemorheology in patients with early DN.METHODS Through a retrospective analysis,123 patients with early DN were admitted to the endocrinology clinic of the Changzhou NO.7 People’s Hospital from January 2021 to October 2022 and were selected as study subjects.After rigorous screening,100 patients with early DN were enrolled.The control group(CG,n=50)and the observation group(OG,n=50)were divided according to the treatment method.The CG were treated with sitagliptin,and the OG were treated with sitagliptin plus the Yiqi yangyin huoxue decoction.Both groups were treated for 3 mo.For both groups,the baseline data and clinical efficacy were compared,and changes in blood glucose levels,lipid levels,renal function,and hematological indicators before(T0)and after(T1)treatment were assessed.RESULTS The total effective rate for the OG was 94.00%and that of the CG was 80.00%(P<0.05).After treatment(T1),the levels of fasting blood glucose,2 h postprandial glucose,total cholesterol,triacylglycerol,and low-density lipoprotein cholesterol in OG patients were obviously lower than those in the CG(P<0.05),and cystatin C,homocysteine,urinary microalbumin,and blood creatinine values in OG patients were also obviously lower than those in the CG(P<0.05);erythrocyte deposition,plasma viscosity,whole blood high shear viscosity,and whole blood low shear viscosity were markedly lower in OG patients than in the CG(P<0.05).CONCLUSION Sitagliptin combined with Yiqi yangyin huoxue decoction has a remarkable effect when used to treat patients with early DN.Further,it is helpful in improving hemorheological indices and controlling disease progression.
基金the National Natural Science Foundation of China(No.51875209)the Guangdong Basic and Applied Basic Research Foundation(No.2019B1515120060)the Open Funds of State Key Laboratory of Nuclear Power Safety Monitoring Technology and Equipment。
文摘Early fault warning for nuclear power machinery is conducive to timely troubleshooting and reductions in safety risks and unnecessary costs. This paper presents a novel intelligent fault prediction method, integrated probabilistic principal component analysis(PPCA), multi-resolution wavelet analysis, Bayesian inference, and RNN model for nuclear power machinery that consider data uncertainty and chaotic time series. After denoising the source data, the Bayesian PPCA method is employed for dimensional reduction to obtain a refined data group. A recurrent neural network(RNN) prediction model is constructed, and a Bayesian statistical inference approach is developed to quantitatively assess the prediction reliability of the model. By modeling and analyzing the data collected on the steam turbine and components of a nuclear power plant, the results of the goodness of fit, mean square error distribution, and Bayesian confidence indicate that the proposed RNN model can implement early warning in the fault creep period. The accuracy and reliability of the proposed model are quantitatively verified.
基金Supported by National Institutes of Health(AREA),No.R15 DK067901-02the Howard Hughes Medical Institute,No.52006328Wilkes Mentoring funds and institutional funds from Wilkes University and TCMC
文摘AIM: To evaluate the efficacy of the improvedthrombospondin mimetic peptide ABT-898 in a murine model of ulcerative colitis. METHODS: The dextran sodium sulfate(DSS) was used for the induction of colitis in both TSP-1 deficient(TSP-1-/-) and wild type(WT) mice during 7 d. While mice were receiving the DSS dissolved in the drinking water, the ABT-898 peptide was dissolved in sterile 5% glucose solution and delivered using mini pumps subcutaneously implanted. Plasma samples were analyzed for interleukin(IL)-6 by ELISA assay and colonic tissues were harvested, fixed and processed for histological evaluation. Immunohistochemistry using antibodies for the detection of CD31 and MECA in endothelial cells was performed. Inflammation was graded in colonic sections and the number of microvessels in each lesion was assessed. Activation of signal transducer and activator of transcription 3(STAT3) in colonic samples was quantified by immunohistochemistry and Western blotting using antibodies against total STAT3 and phosphorylated STAT3(p STAT3)(Ser727).RESULTS: Treatment with ABT-898 considerably diminished the inflammatory response in WT and TSP-1-/- mice(P < 0.0001 in both groups vs control). Identification of blood vessels highlighted by CD31/MECA immunohistochemistry, showed significantly reduced vessel counts in colitic lesions of WT and TSP-1-/- mice treated with ABT898(TSP-1-/- controls/TSP-1-/- treated, P = 0.0002; WT controls/WT treated, P = 0.0005). Consistently, IL-6 was significantly diminished in plasma samples of TSP-1-/- and WT treated with the peptide when compared to the control mice(P = 0.0002 and P = 0.0148, respectively). p STAT3 positive cells were quantified in WT and TSP-1-/- treated with ABT-898. A significant decrease in positive cells for p STAT3 was observed in treated mice(TSP-1-/- controls/TSP-1-/- treated, P = 0.0089; WT/WT treated, P = 0.0110). These results were confirmedby Western blotting analyses showing lower levels of p STAT3 in colitic lesions from mice treated with the peptide ABT-898.CONCLUSION: These findings indicate that the new peptide ABT-898 ameliorates inflammation and angiogenesis and might be a therapeutic alternative in IBD and inflammatory diseases.
文摘The ring opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) initiated by single component of tris(2,6-di-tert-butyl-4-methylphenoxo) lanthanide (Ln(OAr)(3)) is reported. The initiators are highly active to the polymerization and give high molecular weight polymers. (HNMR)-H-1 spectra and DSC measurement suggest the polymerization is free of decarboxylation. Mechanism study shows that the monomer insertion is via the break of acyl-oxygen bond of DTC.
文摘At the 63rd Venice International ,Film Festival concluded on September 9, 2006, the Chinese film ＂Still Life＂ directed by Jia Zhangke won the Golden Lion Award as the best film.Jia＇s documentary ＂The East＂ also won the Italian Documentaries Association Award and the ＂Open 2006＂ Award.
基金support by the Zhejiang Provincial Natural Science Foundation of China(No.LZ22B040001).
文摘The utilization of carbon dioxide(CO_(2))as a C1 feedstock is consistently attractive,especially in the preparation of sustainable polymeric materials.In this contribution,a terpolymer of CO_(2),1,3-butadiene(BD)and epoxide is synthesized by scandium triflate catalyzed cationic ring-opening copolymerization ofα-ethylidene-δ-vinyl-δ-valerolactone(EVL),an intermediate derived from CO_(2)and BD,with epoxides.The obtained terpolymer with a CO_(2)content of 22 mol%has a number-average molecular weight(M_(n))up to 7.8 kg/mol and a dispersity(Đ)of 2.4.The reactivity ratios of EVL and cyclohexene oxide(CHO)are determined as 0.01 and 1.07,respectively,suggesting random characteristic of the terpolymer.The preserved C=C double bonds from BD allow for the further modification of the terpolymer by photoinitiated crosslinking.The yielded networks are fluorescent and degradable.This method offers enhanced versatility to the synthesis and additional functionalization of CO_(2)-based polymers.
基金the Key and General Programs of Modern Agriculture in Jiangsu Province(No.BE2022368)Jiangsu Agricultural Science and Technology Innovation Fund(No.CX(20)1008),China.
文摘Light-emitting diode(LED)irradiation can affect postharvest vegetable and fruit shelf life and nutritional quality.In this study,11 kinds of glucosinolates(GLS)and 6 types of GLS breakdown products were identified in cabbage leaves.To investigate the effects of LED irradiation on quality and GLS metabolism,postharvest cabbage was irradiated with 25μmol/(m2·s)green LED(GL)light at room temperature for 12 d.The dark condition and natural light were used as controls.GL irradiation inhibited the respiration rate and the accumulation of malondialdehyde,and maintained higher cabbage sensory score,chlorophyll content,and antioxidant enzyme activities,thus extending its postharvest shelf life.Additionally,GL irradiation promoted GLS profile accumulation,including glucoraphanin,glucoiberin,gluconapin,gluconasturtiin,glucobrassicin,and sinigrin,which could have resulted from upregulated expression of the transcription factors MYB28 and MYB51,and the key genes involved in GLS biosynthesis(CYP83A1,CYP83B1,ST5b,and UGT74B1).Furthermore,GLS degradation was promoted by this treatment during the late stage of shelf life,as higher myrosinase activity and relative MYR and ESM expression levels were found in treated cabbage leaves,resulting in higher isothiocyanate(ITC)and indole-3-carbinol contents after day 6.Therefore,GL irradiation was beneficial for cabbage preservation.
基金financially supported by the National Natural Science Foundation of China(Nos.51333008,51273214 and 51073176)the project of key technological breakthrough for emerging industries of strategic importance(Nos.2011A091102001,and 2011A091102003)+2 种基金the Science and Technology Program of Guangdong Province(Nos.2010B010800021 and 2010A011300004)the Basic Scientific Research Foundation in Colleges and Universities of Ministry of Education of China(No.12lgjc08)the ST project of Hongyun Honghe Tobacco Group(No.HYHH2013YL06)
文摘Polyurethanes consisting of tri-functional homopolymer of hexamethylene diisocyanate （tri-HDI） and polyethylene glycol （PEG） are synthesized, in which photo-reversible coumarin moieties act as pendant groups. Accordingly, the polyurethanes can be repeatedly self-healed under UV lights at room temperature by taking advantages of the photodimerization and photocleavage habits of coumarin. Molecular weight of the soft segment, PEG, is found to be closely related to the healing performance of the polyurethanes. Lower molecular weight PEG that corresponds to higher initial coumarin concentration in the polymer is critical for obtaining higher healing efficiency in the case of the first healing action. Nevertheless, it does not guarantee high reversibility of the photo-remendability during the repeated healing events. In contrast, the polyurethane with moderate molecular weight PEG has achieved balanced performance. Reaction kinetics is less important for the healing effect.
基金financially supported by the National Natural Science Foundation of China (No. 21871232)Zhejiang Provincial Natural Science Foundation of China (No. LR15B040001)
文摘Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable synthetic technique for functional poly(ε-caprolactone)(PCL) via Janus polymerization, which comprises cationic ring-opening copolymerization (ROP) of ε-caprolactone (CL) with 3,3-bis(chloromethyl)oxacyclobutane (CO) and (coordinated) anionic ROP of CL at a single propagating chain by rare earth metal triflates (RE(OTf)3)and propylene oxide, thus generating block copolymers in one step. The compositions of the copolymers of poly(CLb-(CL-r-CO)) can be modulated by various RE(OTf)3. Scandium triflate catalyzes Janus polymerization to yield the copolymers containing the highest CO contents among all the RE(OTf)3 catalysts used with complete conversion of CL. The chlorine in CO repeating units is ready to be transferred into azide group which affords the modification sites to react with 9-ethynyl-9-fluorenol and mPEG-alkyne, respectively, via copper(I)-catalyzed azide-alkyne cycloaddition reaction with quantitative conversions of azides, as confirmed by FTIR analyses. According to NMR and SEC analyses, copolymers (PCC-g-PEG) bearing a homo-PCL block and a PEG-grafted block of poly(CO-co-CL) demonstrate well-defined chemical structures. The investigations on thermal properties reveal the strong phase separation between PCL and PEG blocks. The amphiphilic PCC-g-PEG is able to sei住assemble into micelles in aqueous solution while cylindrical and lamellar morphologies are observed in bulk. We provide an efficient protocol to synthesize functional PCL combining onestep Janus polymerization and precise post-polymerization click reaction.
基金the French National Research Agency(No.ANR16-CE29-0028)the National Natural Science Foundation of China(No.21674091)+2 种基金the Joint Foundation of Shaanxi Province Natural Science Basic Research ProgramShaanxi Coal Chemical Group Co.,Ltd.(No.2019JLM-46)for financial supportthe China Scholarship Council for funding his Ph.D.scholarship in France。
文摘Amphiphilic block copolymers poly(ethylene glycol)-block-poly(N-3-(methylthio)propyl glycine)(PEGb-PMeSPG)were synthesized via ring-opening polymerization of N-3-(methylthio)propyl glycine Nthiocarboxyanhydride(MeSPG-NTA)initiated by amino-terminated PEG.The self-assemblies of three PEG-b-PMeSPG copolymers with different PMeSPG block lengths were first prepared by nanoprecipitation method using THF and DMF,respectively,as the organic solvent,and their morphologies were studied by Cryo-EM and DLS.To prepare polymersomes loaded with glucose oxidase(GOx),double emulsion method followed by extrusion treatment was employed.The oxidation-responsive disruption of polymersomes was achieved upon the introduction of glucose because of the oxidants generated insitu by GOx/glucose.
基金financially supported by the National Natural Science Foundation of China (No. 21871232)the Zhejiang Provincial Natural Science Foundation of China (No. LR15B040001)
文摘Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including(1) fast cationic polymerization with slow anionic one,(2) fast anionic polymerization with dormant cationic one, and(3)reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory(DFT)calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results.
文摘To substantially prevent electromagnetic threatens,microwave absorbing materials(MAMs)are required to eliminate surplus electromagnetic waves.As a typical MAM,Fe_(3)O_(4) particles with complex permittivity and permeability have been widely applied due to the coexistence of magnetic loss and dielectric loss.However,the necessary high mass fraction significantly limited its applications,thus Fe_(3)O_(4) nanostructures have been extensively investigated to overcome this problem.In this work,uniform Fe_(3)O_(4) nanobelts were prepared by electrospinning and two-step thermal treatment.By controlling the composition and viscosity of the electrospinning precursor solution,Fe_(3)O_(4) nanobelts with tunable lateral sizes(200 nme1 mm)were obtained.The samples with low content(only 16.7 wt%)Fe_(3)O_(4) exhibited wide maximum effective absorbing bandwidths(EAB)over 3 GHz,and Fe_(3)O_(4) nanobelts with smaller lateral sizes showed a maximum EAB of 4.93 GHz.Meanwhile,Fe_(3)O_(4) nanobelts with smaller lateral sizes presented superior reflection loss properties,the lowest reflection loss reached-53.93 dB at 10.10 GHz,while the maximum EAB was up to 2.98 GHz.The excellent microwave reflection loss of Fe_(3)O_(4) nanobelts was contributed to the enhanced synergistic effect of magnetic loss,dielectric loss,and impedance matching,originated from the hierarchically cross-linked networks and shape anisotropies.This study could broaden the practical applications of magnetic absorbers,and provided an approach for the development of shape anisotropic magnetic materials.
基金Joint Foundation of Shaanxi Province Natural Science Basic Research Program and Shaanxi Coal Chemical Group Co.,Ltd.(No.2019JLM-46)the National Natural Science Foundation of China(No.21674091).
文摘The synthesis of block copolymers of poly(tetrahydrofuran)-b-poly(α-amino acid)(PTHF-b-PAA)is challenging since it is difficult to combine the two blocks produced via different/conflicting ring-opening polymerization(ROP)mechanisms.In this contribution,the cationic ROP of THF is catalyzed by rare-earth triflate[RE(OTf)3]and terminated by 2-(t-butyloxycarbonyl-amino)ethanol(BAE).After the deprotection of t-butyloxycarbonyl(Boc)group,the chain end of PTHF is quantitatively changed to amino group which thereafter initiates the nucleophilic ROP ofα-amino acid N-thiocarboxyanhydrides(NTAs).Both polymerizations are well controlled,generating PTHF and PAA segments with designable molecular weights(MWs).PTHF-b-polylysine(PTHF-b-PLys)and PTHF-b-polysarcosine(PTHF-b-PSar)are obtained with MWs between 8.6 and 28.7 kg/mol.The above amphiphilic diblock copolymers form micelles in water.PTHF40-b-PSar32 acts as a surfactant to stabilize oil-in-water emulsions.Both segments of PTHF-b-PAA are biocompatible and promising in the biomedical application.
基金the National Natural Science Foundation of China，Chinese Academy of Sciences,and Shanghai Science and Technology Commission
文摘A series of donor-acceptor oligomer OBTThn （n = 1- 7） and polymer PBTThl and PBTTh2 composed of al- ternative 2,1,3-benzothiadiazole and 3-hexylthiophene have been designed and synthesized for the purpose of in- vestigation on the effect of chain length and side-chain regioregularity on their basic properties and photovoltaic performance. In the OBTThn oligomers and PBTThl polymer, all the hexyl side chains on thienyl units orient to- ward the same direction. Upon elongation of the chain length, the intramolecular charge transfer （ICT） absorption band in solution gradually redshifts from 398 nm for OBTThl to 505 nm for OBTThT, then to 512 nm for PBTThl polymer. Meanwhile, the HOMO energy level increases from -5.45 eV （OBTTh0 to -5.08 eV （OBTThT） and -5.09 eV （PBTThl）, and the LUMO energy level decreases from -3.11 eV （OBTTh0 to -3.30 eV （OBTThT） and -3.33 eV （PBTThl）, thus giving a smaller and smaller energy bandgap for higher oligomers and polymers. Theo- retical calculation suggests straight line-like backbone geometry for this series of oligomers and polymer. On the other hand, polymer PBTTh2 possesses a different side-chain regioregularity, in which every two neighbor hexyl side chains are arranged in different orienting direction. It is theoretically suggested to have curved line-like back- bone geometry. In solution, it shows similar photophysical and electrochemical properties as PBTThl. However in film state, it displays a less redshift in the ICT band as refer to that in solution than PBTThl. In combination with [6,6]-phenyl-C61-butyric acid methyl ester （PC61BM）, these oligomers and polymers were used as donor material to fabricate organic bulk heterojunction solar cells. Again, chain length-dependent device photovoltaic performance was observed. The device based on OBTTh4 showed a power conversion efficiency of 0.16%, while it increased to 0.36% and 0.49% for the devices based on OBTTh6 and PBTThb respectively. However, the side-chain regio- regularity has less influence on the device photovoltaic output since the device based on PBTTh~ displayed an effi- ciency of 0.52%, comparable to that of PBTThl.
基金supported by the National Natural Science Foundationof China(No.21871232)。
文摘Janus polymerization consists of anionic and cationic ring opening polymerizations(AROP and CROP)at the two ends of a single propagating polymer chain,followed by a self-triggered chain extension generating multiblock copolymers(MBCPs)in one step.In the contribution,Janus polymerization by Tm(OTf)_(3) or Er(OTf)_(3) catalyst with an epoxy initiator is applied to synthesize MBCPs of semi-crystalline poly(ε-caprolactone)(PCL)blocks from coordinated AROP and poly(1,3-dioxolane-co-ε-caprolactone)(P(DO-co-CL))blocks from CROP of DO with CL.Meanwhile,amorphous random copolymers[P(DO-r-CL)]are synthesized as control by employing other rare earth triflates[RE(OTf)_(3),RE=Y,Nd,Gd and Lu]as catalysts or in the absence of an initiator via CROP.On account of the distinguishable chemical structures and thermal properties between Janus MBCPs and cationic random copolymers,Janus features are confirmed including the CROP and AROP at a single propagating chain.The resultant amphiphilic copolymers self-assemble to nanoparticles in aqueous solution with designable diameters with the corresponding ratios of hydrophilic and hydrophobic seg-ments.MBCPs exhibit good shape memory properties with appropriate deformation temperature close to human body's,providing a prospect on the applications in biomedical devices.
基金supported by the National Natural Science Foundation of China(nos.21788102 and 21525417)the Natural Science Foundation of Guangdong Province(nos.2019B030301003 and 2016A030312002)the Innovation and Technology Commission of Hong Kong(no.ITC-CNERC14S01).
文摘In comparing with traditional polymer degradation toward unknown or unvalued products(i.e.,downcycling),new methods to degrade polymers into monomers or high-value-added materials(i.e.,upcycling)are preferable for sustainable developments.In this work,CO_(2)-based linear and cross-linked unsaturated polyesters,that is,poly(alkynoate)s,were successfully degraded by benzamidine into diols and high-value-added pyrimidone or imidazolone derivatives through controlled reaction conditions.The degradation process could be visualized under UV light via gradually increased luminescent intensity of the reaction mixtures and fluorescence patterns could be generated through microcontact printing of the stamp on the thin films of poly(alkynoate)s.Moreover,the pyrimidone derivatives could be applied in bioimaging and inhibiting bacteria,and the imidazolone derivatives could be used for the detection and recovery of gold(III)ions from electronic waste and serve as the fluorescent sensor to detect in situ-generated amines from food spoilage.Thus,this work presents a visualized and high value productselective degradation to solve the end-of-life issue of polymers.
