BACKGROUND Traditional lymph node stage(N stage)has limitations in advanced gastric remnant cancer(GRC)patients;therefore,establishing a new predictive stage is necessary.AIM To explore the predictive value of positiv...BACKGROUND Traditional lymph node stage(N stage)has limitations in advanced gastric remnant cancer(GRC)patients;therefore,establishing a new predictive stage is necessary.AIM To explore the predictive value of positive lymph node ratio(LNR)according to clinicopathological characteristics and prognosis of locally advanced GRC.METHODS Seventy-four patients who underwent radical gastrectomy and lymphadenectomy for locally advanced GRC were retrospectively reviewed.The relationship between LNR and clinicopathological characteristics was analyzed.The survival analysis was performed using Kaplan-Meier survival curves and Cox regression model.RESULTS Number of metastatic LNs,tumor diameter,depth of tumor invasion,Borrmann type,serum tumor biomarkers,and tumor-node-metastasis(TNM)stage were correlated with LNR stage and N stage.Univariate analysis revealed that the factors affecting survival included tumor diameter,anemia,serum tumor biomarkers,vascular or neural invasion,combined resection,LNR stage,N stage,and TNM stage(all P<0.05).The median survival time for those with LNR0,LNR1,LNR2 and LNR3 stage were 61,31,23 and 17 mo,respectively,and the differences were significant(P=0.000).Anemia,tumor biomarkers and LNR stage were independent prognostic factors for survival in multivariable analysis(all P<0.05).CONCLUSION The new LNR stage is uniquely based on number of metastatic LNs,with significant prognostic value for locally advanced GRC,and could better differentiate overall survival,compared with N stage.展开更多
Increasing the osteogenic differentiation ability and decreasing the adipogenic differentiation ability of bone marrow mesenchymal stem cells(BMSCs)is a potential strategy for the treatment of osteoporosis(OP).Natural...Increasing the osteogenic differentiation ability and decreasing the adipogenic differentiation ability of bone marrow mesenchymal stem cells(BMSCs)is a potential strategy for the treatment of osteoporosis(OP).Naturally derived oligosaccharides have shown significant anti-osteoporotic effects.Nystose(NST),an oligosaccharide,was isolated from the roots of Morinda officinalis How.(MO).The aim of the present study was to investigate the effects of NST on bone loss in ovariectomized mice,and explore the underlying mechanism of NST in promoting differentiation of BMSCs to osteoblasts.Administration of NST(40,80 and 160 mg/kg)and the positive control of estradiol valerate(0.2 mg/kg)for 8 weeks significantly prevented bone loss induced by ovariectomy(OVX),increased the bone mass density(BMD),improved the bone microarchitecture and reduced urine calcium and deoxypyridinoline(DPD)in ovariectomized mice,while inhibited the increase of body weight without significantly affecting the uterus weight.Furthermore,we found that NST increased osteogenic differentiation,inhibited adipogenic differentiation of BMSCs in vitro,and upregulated the expression of the key proteins of BMP and Wnt/β-catenin pathways.In addition,Noggin and Dickkopf-related protein-1(DKK-1)reversed the effect of NST on osteogenic differentiation and expression of the key proteins in BMP and Wnt/β-catenin pathway.The luciferase activities and the molecular docking analysis further supported the mechanism of NST.In conclusion,these results indicating that NST can be clinically used as a potential alternative medicine for the prevention and treatment of postmenopausal osteoporosis.展开更多
Semiconducting polymers(SPs)have shown great feasibility as candidates for near-infrared-II(NIR-Ⅱ)fluorescence imaging-navigated photothermal therapy due to their strong light-harvesting ability and flexible tunabili...Semiconducting polymers(SPs)have shown great feasibility as candidates for near-infrared-II(NIR-Ⅱ)fluorescence imaging-navigated photothermal therapy due to their strong light-harvesting ability and flexible tunability.However,the fluorescence signal of traditional SPs tends to quench in their aggregate states owing to the strongπ-πstacking,which can lead to the radiative decay pathway shutting down.To address this issue,aggregation-induced emission effect has been used as a rational tactic to boost the aggregate-state fluorescence of NIR-Ⅱemitters.In this contribution,we developed a precise molecular engineering tactic based on the block copolymerizations that integrate planar and twisted segments into one conjugated polymer backbone,providing great flexibility in tuning the photophysical properties and photothermal conversion capacity of SPs.Two monomers featured with twisted and planar architectures,respectively,were tactfully incorporated via a ternary copolymerization approach to produce a series of new SPs.The optimal copolymer(SP2)synchronously shows desirable absorption ability and good NIR-Ⅱquantum yield on the premise of maintaining typical aggregation-induced emission characteristics,resulting in balanced NIR-Ⅱfluorescence brightness and photothermal property.Water-dispersible nanoparticles fabricated from the optimal SP2 show efficient photothermal therapeutic effects both in vitro and in vivo.The in vivo investigation reveals the distinguished NIR-Ⅱfluorescence imaging performance of SP2 nanoparticles and their photothermal ablation toward tumor with prominent tumor accumulation ability and excellent biocompatibility.展开更多
Objective:Pancreatic ductal adenocarcinoma(PDAC)is a disease with high mortality.Many so-called"junk"noncoding RNAs need to be discovered in PDAC.The purpose of this study was therefore to investigate the fu...Objective:Pancreatic ductal adenocarcinoma(PDAC)is a disease with high mortality.Many so-called"junk"noncoding RNAs need to be discovered in PDAC.The purpose of this study was therefore to investigate the function and regulatory mechanism of the long noncoding RNA MEG3 in PDAC.Methods:The Gene Expression Omnibus database(GEO database)was used to determine the differential expression of long noncoding RNAs in PDAC,and MEG3 was selected for subsequent verification.Tissue and cell samples were used to verify MEG3 expression,followed by functional detection in vitro and in vivo.Microarrays were used to characterize long noncoding RNA and mRNA expression profiles.Competing endogenous RNA analyses were used to detect differential MEG3 and relational miRNA expression in PDAC.Finally,promoter analyses were conducted to explain the downregulation of MEG3 PDAC.Results:We generated a catalogue of PDAC-associated long noncoding RNAs in the GEO database.The ectopic expression of MEG3 inhibited PDAC growth and metastasis in vitro and in vivo,which was statistically significant(P<0.05).Microarray analysis showed that multiple microRNAs interacted with MEG3.We also showed that MEG3,as a competing endogenous RNA,directly sponged miR-374a-5p to regulate PTEN expression.The transcription factor,Sp1,recruited EZH2 and HDAC3 to the promoter and transcriptionally repressed MEG3 expression.Finally,clinical data showed that MEG3 and miR-374a-5p expressions were correlated with clinicopathological features.Statistically,Sp1,EZH2,HDAC3,and miR-374 a-5p were negatively correlated with MEG3(P<0.05).Conclusions:Reduced MEG3 levels played a crucial role in the PDAC malignant phenotype,which provided insight into novel and effective molecular targets of MEG3 for pancreatic cancer treatment.展开更多
BACKGROUND Pseudohypoparathyroidism type Ia(PHP Ia) is a rare hereditary syndrome, and patients with early PHP Ia are generally not diagnosed based on the presentation of cutaneous nodules as the main clinical feature...BACKGROUND Pseudohypoparathyroidism type Ia(PHP Ia) is a rare hereditary syndrome, and patients with early PHP Ia are generally not diagnosed based on the presentation of cutaneous nodules as the main clinical feature. Here, we describe a Chinese boy with PHP Ia in whom the main clinical feature was cutaneous nodules, and the patient exhibited a novel GNAS mutation.CASE SUMMARY A 5-year-old boy presented with a 5-year history of cutaneous nodules scattered over his entire body. The patient had a short stature, round face, short neck, and slightly flattened nose;he also had multiple hard papules and cutaneous nodules scattered over his entire body. The patient had a significantly elevated parathyroid hormone level. His serum calcium level was reduced, while his serum phosphorus level was increased and his serum thyroid-stimulating hormone level was elevated. Skin biopsy showed osteoma cutis in subcutaneous tissue. Sanger sequencing revealed a frameshift mutation, c.399 del T(p.Ser133 Argfs*2) in exon 5 of the GNAS gene. The patient was diagnosed with PHP Ia and subclinical hypothyroidism. He was given 1,25-dihydroxyvitamin D,calcium carbonate, and synthetic L-thyroxine. After 3 months of treatment, the patient’s parathyroid hormone level decreased, and his serum calcium and serum phosphorus levels were normal. Moreover, his thyroid-stimulating hormone level decreased.CONCLUSION These findings can help dermatologists to diagnose PHP Ia in patients with cutaneous nodules as the main early clinical feature.展开更多
[Objectives]To analyze the current research situation,hotspots and trends of curcumin and diabetes in recent 10 years.[Methods]Web of Science database was set as data source,the annual number of papers,the distributio...[Objectives]To analyze the current research situation,hotspots and trends of curcumin and diabetes in recent 10 years.[Methods]Web of Science database was set as data source,the annual number of papers,the distribution of authors,the distribution of country/institution,the distribution of journals,the distribution of key words in the literature about curcumin and diabetes from January 1,2010 to March 31,2021 were quantitatively and visually analyzed with the aid of visualization software Bibliometrix.[Results]A total of 475 articles were included,and the annual number of papers was on the rise;the top three high-yielding countries were China(120 papers),India(65 papers),and the United States(58 papers).In terms of international cooperation,China and the United States had the most cooperation(27 papers);the top three high-yielding institutions were Wenzhou Medical University(42 papers),Mashhad University of Medical Sciences(41 papers)and Tehran University of Medical Sciences(30 papers);the most frequently cited authors were Wang Y(19 times),Li X(13 times),Li Y(12 times),Liang G(12 times)and Zhang Y(12 times);the top three journals in number of papers were Diabetology&Metabolic Syndrome(8 papers),PLoS One(8 papers),and European Journal of Pharmacology(7 papers),and the h index was 7,8,and 6,respectively;the most frequently cited journals were Diabetes(496 times),Journal of Biological Chemistry(486 times),PLoS One(347 times),Diabetes Care(284 times),and European Journal of Pharmacology(229 times);the most frequent key words mainly included oxidative stress,curcumin,insulin-resistance and expression;the hotspots were insulin resistance and NF-κB,mainly focusing on in vitro experiments.[Conclusions]The curcumin has good therapeutic potential in improving insulin resistance,inhibiting inflammation and oxidative stress,etc.The results are expected provide a reference and basis for scientific researchers to understand the current situation of curcumin and diabetes research and carry out the further research.展开更多
. In this article, we describe the characteristics of large-scale modeling of the theme text of this site data and important progress in recent years. Topic modeling approach has attracted wide interest in the world, .... In this article, we describe the characteristics of large-scale modeling of the theme text of this site data and important progress in recent years. Topic modeling approach has attracted wide interest in the world, and promote a number of important data mining, development of computer vision and computational biology applications, including automatic text summaries, information retrieval, information recommendation, topic detection and tracking, natural scene understanding human action recognition and gene expression analysis. The main features of the model and the corresponding theme paper focuses on the text of this site data. Data with dynamic, high-end, multi-channel and distributed structure and the structure of the model is only part of the theme before modeling. The paper discussed in the framework of the unity of the three-dimensional Markov model of four structural features of the text of this site data modeling, and analysis of distributed computing and word combination of three-dimensional modeling topics Markov model and type fuzzy systems the possibility of applications. In addition to structural modeling for this site text data, also we discuss some of the three-dimensional Markov model energy minimization of machine learning algorithms.展开更多
With Internet technology research and gradually used in modern distance education practice, high-bandwidth, high-speed, high-reliability remote education network will be able to provide better education services to cr...With Internet technology research and gradually used in modern distance education practice, high-bandwidth, high-speed, high-reliability remote education network will be able to provide better education services to create some more opportunities and possibilities. Multimedia courseware contains audio, video and other large-capacity information object, it has been widely used in practice of distance education, distance education and the overall quality of service has a greatly improved. However, due to the current courseware file size is very large, the user wants to browse the courseware, need to start on the site to download and then watch to play, if the change in the place of learning, we need to download again, very cumbersome and inefficient. In order to facilitate the user can at any time and place can conveniently browse online courseware streaming media technology came into being. Streaming media technology has been widely used in audio, video online play. Times for large data interaction design connotation and denotation, and development course contents and scope, we analyze and estimate the large interaction design trends in the information age of big data interaction design methods, processes, architectures, models and assessments, to explore a large design interactive design strategy and design details.展开更多
Azadirachta indica A. Juss is a tropical evergreen plant, belonging to the Meliaceae family. The plant is used as folk medicines for the treatment of fever, neuromuscular pains, skin infections, diabetes and heart dis...Azadirachta indica A. Juss is a tropical evergreen plant, belonging to the Meliaceae family. The plant is used as folk medicines for the treatment of fever, neuromuscular pains, skin infections, diabetes and heart disease. Previous researches show that the plant possesses several types of chemical constituents and diverse biological activities. The paper concludes chemical constituents, biological activities and pesticide products of A. indica.展开更多
Porous organic polymers(POPs)have attracted great attention in past decades.Although diverse functional POPs have been developed,multistimuli-responsive POPs with excellent aggregate-state luminescence together with g...Porous organic polymers(POPs)have attracted great attention in past decades.Although diverse functional POPs have been developed,multistimuli-responsive POPs with excellent aggregate-state luminescence together with good chiroptical properties have rarely been reported.Herein,two pairs of Salen-type enantiomeric PoPs with multistimuli-responsive luminescence and chiral features were designed and synthesized by facile polycondensation reactions between polyfunctional aggregation-induced emission luminogen(AlEgen)-containing salicylaldehyde derivatives and chiral diamines.With Salen units in polymer backbones as tetradentate ligands,a series of POP-metal complexes were further prepared.The obtained POPs and metal complexes show good porosity,high thermal stability,and obvious circular dichroism signals.Moreover,benefiting from the coexistence of AlEgen and Salen units in polymer structures,these POPs exhibit excellent luminescence performance in aggregate states and tunable fluorescence behaviors in response to external stimuli of Zn^(2+)ion,mechanical forces,organic solvent,and acids.Due to the dynamic feature of Schiff base C=N bonds,the present POPs can efficiently undergo hydrolysis reactions under strong acidic conditions to reproduce the AlEgencontaining monomers,and such an acid-induced degradation process can be directly visualized and dynamically monitored via fluorescence variation.These properties collectively make the POPs candidate materials for applications in heterogeneous asymmetric catalysis,fluorescence sensing,biomedicine,etc.展开更多
Background:Very few studies have been conducted regarding the optimal time interval between hysteroscopic adhesiolysis and the embryo transfer(ET).Investigation of this optimal time may be helpful for assisted reprodu...Background:Very few studies have been conducted regarding the optimal time interval between hysteroscopic adhesiolysis and the embryo transfer(ET).Investigation of this optimal time may be helpful for assisted reproductive technology.Therefore,we investigated effects of the interval between hysteroscopic adhesiolysis and ET upon in vitro fertilization(IVF)cycle outcomes.Methods:Patients were recruited between January 2014 and September 2017 at the Reproductive Hospital Affiliated to Shandong University.Patients who were diagnosed with intra-uterine adhesion(IUA)and underwent hysteroscopic adhesiolysis before fresh IVF-ET or intra-cytoplasmic sperm injection cycles were classified into three groups according to the interval between hysteroscopic adhesiolysis and ET:less than 90 days(Group 1),90 to 180 days(Group 2),and greater than 180 days(Group 3).Baseline characteristics,controlled ovarian stimulation(COS)response,and pregnancy outcomes after ET were compared.Analysis of variance or non-parametric tests were used to test numerical data.The Pearson’s Chi-squared test was used to test categorical data.Results:A total of 312 patients were recruited as follows:112 in Group 1,137 in Group 2,and 63 in Group 3.There were no differences in baseline and COS characteristics among the three groups.The live-birth rate in Group 2(40.1%)was significantly higher than that in Group 1(17.9%;χ^2=14.545,P<0.001).There were no significant differences in the rates of biochemical,ongoing,and clinical pregnancy,and biochemical and clinical pregnancy abortion,as well as stillbirth among the groups.In the mild IUA patients,the live-birth rate was significantly higher in Group 2(42.6%)compared with Group 1(22%;χ^2=8.413,P=0.004).In the moderate IUA patients,Group 2(35.7%)had a higher frequency of live births than Group 1(6.7%;χ^2=8.187,P=0.004).Conclusions:The optimal waiting period for fresh ET after hysteroscopic adhesiolysis was 90 to 180 days in the current study.展开更多
As the largest iron and steel producer in China, a part of Baosteel moved out of Shanghai deserves close attention due to its environmental impact. To understand the effect of Baosteel emission control on air quality ...As the largest iron and steel producer in China, a part of Baosteel moved out of Shanghai deserves close attention due to its environmental impact. To understand the effect of Baosteel emission control on air quality in Shanghai, daily PM10, PM2.5, SO2, NO2 and CO were measured from 2010 to 2016. Concentrations of pollutants in Baoshan District presented a decreased trend during 2010-2016, with a reduction rate of 28.6% for PM10, 67.3% for SO2, 8.6% for NO2 and 42.0% for CO. However, fine particle pollution in Baoshan District during 2012-2016 seems to become more prominent, with PM2.5 concentration of 47 ± 28, 45 ± 33, 38 ± 24, 54 ± 41 and 51 ± 34 μg/m^3, respectively, indicating a slight increase of 8.5% in PM2.5. Concentrations of PM10 and CO decreased by 12.5% and 33.8% in the second half year in 2016 （compared with that in 2015） probably due to closure of blast furnace of Baosteel. Baosteel was identified as the largest pollution source in Baoshan District. Emission from Baosteel accounted for 58.0% of SO2, 43.6% of NO2 and 79.3% of dust in total emission from Baoshan District during 2010-2015. Meanwhile, pollutant emission and coal consumption from Baosteel decreased by 52.0% for SO2, 40.1% for NO2, 15.7% for dust and 22% for coal consumption. Energy consumption in Baoshan District reduced by 31% from 2011 to 2015. Air quality improvement in Shanghai was attributed to local emission reduction, together with regional air quality improvement.展开更多
The development of new and efficient polymerization strategies for the synthesis of multisubstituted fused heterocyclic polymers with attractive properties is of great significance.Herein,a rhodium-catalyzed polyannul...The development of new and efficient polymerization strategies for the synthesis of multisubstituted fused heterocyclic polymers with attractive properties is of great significance.Herein,a rhodium-catalyzed polyannulation route is developed for the in situ generation of multisubstituted polyquinolines with efficient aggregate-state fluorescence.Based on the cascade C-H activation of isonicotinamides and their annulations with internal diynes,a series of high molecular weight polyquinolines are efficiently produced in high yields of up to 99%in a facile and atom-economical manner.Unlike conventional two-component stepwise polymerizations,these polyannulation reactions are tolerant to monomer non-stoichiometric conditions and proceed even more thoroughly in the presence of an excess amount of the isonicotinamide monomer.Benefiting from the unique multisubstituted polyquinoline structures,the obtained polymers show high thermal and morphological stability,useful aggregation-induced emission(AIE)properties,and tunable aggregated-state fluorescence behaviors.The AIE-active polyquinoline is demonstrated to be a good lysosome-specific fluorescent probe with low cytotoxicity and excellent photostability.展开更多
Functional materials with circularly polarized luminescence(CPL)have attracted tremendous attention due to their promising applications in three-dimensional dis-plays,chiral recognition and catalysis,photoelectronic d...Functional materials with circularly polarized luminescence(CPL)have attracted tremendous attention due to their promising applications in three-dimensional dis-plays,chiral recognition and catalysis,photoelectronic devices,contrast imaging,information encryption,and otherfields.Among various CPL-active materials,poly-meric systems with aggregation-induced emission(AIE)have emerged as excellent candidates because of their efficient aggregate-statefluorescence,large solid-state dissymmetry factor,excellent processibility,diversified self-assembly behaviors,and readily switchable CPL properties.This review summarizes and discusses the recent progress as well as future perspective of diverse AIE polymer systems with CPL,including CPL-active covalent AIE polymers,CPL-active supramolecular AIE polymers,and AIEgen/polymer composites with CPL.According to the loca-tion or introduction method of AIEgen in polymer structures,this review further divides CPL-active covalent AIE polymers into three categories,including polymers with AIEgen in main chains,polymers with AIEgen in side chains,and CPL-active polymers with clusterization-triggered emission.CPL-active supramolecular AIE polymers are discussed based on the driving force for the formation of supramolecular polymers,including host–guest interactions,metal coordination,and other non-covalent interactions.Moreover,examples on the construction of CPL-active AIEgen/polymer composites by physically mixing AIEgens with chi-ral(supra)polymers are also presented.This review is anticipated to provide readers with an overall view on the design strategies of CPL-active AIE polymers,and facil-itate further research on the development of CPL materials and AIE polymers with advanced applications.展开更多
Aggregation-induced emission(AIE)refers to a photophysical effect that the luminescence of aggregates is stronger than that of the dispersed state.Since the concept of AIE was coined by Professor Ben Zhong Tang and co...Aggregation-induced emission(AIE)refers to a photophysical effect that the luminescence of aggregates is stronger than that of the dispersed state.Since the concept of AIE was coined by Professor Ben Zhong Tang and co-workers in 2001,AIE has evolved from a simple luminescent phenomenon to a multidisciplinary research field with a widespread influence.It has changed people's way of thinking about chromophore aggregation and greatly promoted the development of advanced luminescent materials.During the 20-year development,diverse AIE luminogens(AlEgens)with attractive functionalities have been developed and remarkable achievements have been made in the mechanistic study and high-tech applications of AlEgens.In this review,we provide an overview of the historical development and representative achievements of AIE research.Perspectives on the application of AIE in aggregate science are also briefly discussed to guide the future development in this field.展开更多
Azide-alkyne click polymerization has become a powerful tool for polymer synthesis.However,the click polymerization between internal alkynes and azides is rarely utilized to prepare functional polymers.In this work,th...Azide-alkyne click polymerization has become a powerful tool for polymer synthesis.However,the click polymerization between internal alkynes and azides is rarely utilized to prepare functional polymers.In this work,the polymerization reactions of activated internal alkyne monomers of tris(2-butynoate)s(1)with tetraphenylethene-containing diazides(2)were performed in dimethylformamide(DMF)under simple heating,affording four hyperbranched poly(methyltriazolylcarboxylate)s(hb-PMTCs)with high molecular weights(A4W up to 2.4 x 104)and regioregularities(up to 83.9%)in good yields.The hb-PMTCs are soluble in common organic solvents,and thermally stable with 5%weight loss temperatures up to 400℃.They are non-emissive in dilute solution,but become highly emissive in aggregated state,exhibiting aggregationinduced emission characteristics.The polymers can generate fluorescent photopatterns with high resolution,and can work as fluorescent sensors to detect nitroaromatic explosive with high sensitivity.展开更多
The copper-catalyzed and metal-free azide-alkyne click polymerizations have become efficient tools for polymer synthesis. However,the 1,3-dipolar polycycloadditions between internal alkynes and azides are rarely emplo...The copper-catalyzed and metal-free azide-alkyne click polymerizations have become efficient tools for polymer synthesis. However,the 1,3-dipolar polycycloadditions between internal alkynes and azides are rarely employed to construct functional polymers. Herein, the polycycloadditions of dibutynoate(1) and tetraphenylethene-containing diazides(2) were carried out at 100 °C for 12 h under solvent-and catalyst-free conditions, producing soluble poly(methyltriazolylcarboxylate)s(PMTCs) with high molecular weights in high yields. The resultant polymers were thermally stable with 5% weight loss temperatures up to 377 °C. The PMTCs showed aggregation-induced emission(AIE)properties. They could work as fluorescent sensors for detecting explosive with high sensitivity, and generate two-dimensional fluorescent photopatterns with high resolution. Furthermore, their triazolium salts could be utilized for cell-imaging applications.展开更多
AzoR is a homodimeric,flavin mononucleotide（FMN）-containing,NADH-dependent azoreductase from Escherichia coli.In this paper,we investigated the effect of the concentration of both AzoR and R59 G on the spectral beha...AzoR is a homodimeric,flavin mononucleotide（FMN）-containing,NADH-dependent azoreductase from Escherichia coli.In this paper,we investigated the effect of the concentration of both AzoR and R59 G on the spectral behavior of the bound FMN using two-dimensional fluorescence correlation spectra.Two cross peaks（530,490） and（580,530） were observed from the dilution-induced 2D asynchronous correlation map of wt AzoR,while only one cross peak appeared at（600,530） for R59 C mutant.This result indicated that the mutation at site 59 influenced the formation of dilution-induced intermediates.The specific activity of both AzoR and R59 G mutant was unaffected by dilution when the enzyme concentration is below 1 μmol/L,which suggested that no significant dissociation of FMN occurred at low concentrations.Additionally,in order to explore the origin of these intermediates,we carried out a2 D correlation analysis using excitation wavelength-dependent fluorescence emission spectroscopy.The results showed that there coexisted two types of FMN that emitted fluorescence at 530 nm and 500 nm,respectively.Taken together,these results suggested that the 2D method is a very powerful method to identify the heterogeneous distribution of the bound FMN in solution.展开更多
基金Shanghai Municipal Committee of Science and Technology,No.21Y11913200。
文摘BACKGROUND Traditional lymph node stage(N stage)has limitations in advanced gastric remnant cancer(GRC)patients;therefore,establishing a new predictive stage is necessary.AIM To explore the predictive value of positive lymph node ratio(LNR)according to clinicopathological characteristics and prognosis of locally advanced GRC.METHODS Seventy-four patients who underwent radical gastrectomy and lymphadenectomy for locally advanced GRC were retrospectively reviewed.The relationship between LNR and clinicopathological characteristics was analyzed.The survival analysis was performed using Kaplan-Meier survival curves and Cox regression model.RESULTS Number of metastatic LNs,tumor diameter,depth of tumor invasion,Borrmann type,serum tumor biomarkers,and tumor-node-metastasis(TNM)stage were correlated with LNR stage and N stage.Univariate analysis revealed that the factors affecting survival included tumor diameter,anemia,serum tumor biomarkers,vascular or neural invasion,combined resection,LNR stage,N stage,and TNM stage(all P<0.05).The median survival time for those with LNR0,LNR1,LNR2 and LNR3 stage were 61,31,23 and 17 mo,respectively,and the differences were significant(P=0.000).Anemia,tumor biomarkers and LNR stage were independent prognostic factors for survival in multivariable analysis(all P<0.05).CONCLUSION The new LNR stage is uniquely based on number of metastatic LNs,with significant prognostic value for locally advanced GRC,and could better differentiate overall survival,compared with N stage.
基金support from the Public Platform of Medical Research Center,Academy of Chinese Medical Science,Zhejiang Chinese Medical Universitysponsored by the National Natural Science Foundation of China(81973534,U1505226)。
文摘Increasing the osteogenic differentiation ability and decreasing the adipogenic differentiation ability of bone marrow mesenchymal stem cells(BMSCs)is a potential strategy for the treatment of osteoporosis(OP).Naturally derived oligosaccharides have shown significant anti-osteoporotic effects.Nystose(NST),an oligosaccharide,was isolated from the roots of Morinda officinalis How.(MO).The aim of the present study was to investigate the effects of NST on bone loss in ovariectomized mice,and explore the underlying mechanism of NST in promoting differentiation of BMSCs to osteoblasts.Administration of NST(40,80 and 160 mg/kg)and the positive control of estradiol valerate(0.2 mg/kg)for 8 weeks significantly prevented bone loss induced by ovariectomy(OVX),increased the bone mass density(BMD),improved the bone microarchitecture and reduced urine calcium and deoxypyridinoline(DPD)in ovariectomized mice,while inhibited the increase of body weight without significantly affecting the uterus weight.Furthermore,we found that NST increased osteogenic differentiation,inhibited adipogenic differentiation of BMSCs in vitro,and upregulated the expression of the key proteins of BMP and Wnt/β-catenin pathways.In addition,Noggin and Dickkopf-related protein-1(DKK-1)reversed the effect of NST on osteogenic differentiation and expression of the key proteins in BMP and Wnt/β-catenin pathway.The luciferase activities and the molecular docking analysis further supported the mechanism of NST.In conclusion,these results indicating that NST can be clinically used as a potential alternative medicine for the prevention and treatment of postmenopausal osteoporosis.
基金supported by the funding from the National Natural Science Foundation of China(22271197 and 22225506)the Guangdong Basic and Applied Basic Research Foundation(2023A1515011578 and 2022A1515110146)+2 种基金the Natural Science Foundation for Distinguished Young Scholars of Guangdong Province(2020B1515020011)Shenzhen Key Laboratory of Functional Aggregate Materials(ZDSYS20211021111400001)the Shenzhen Science and Technology Program(RCYX20221008092924059,JCYJ20220531102601003,JCYJ20190808142403590,KQTD20210811090142053,and JCYJ20220818103007014).
文摘Semiconducting polymers(SPs)have shown great feasibility as candidates for near-infrared-II(NIR-Ⅱ)fluorescence imaging-navigated photothermal therapy due to their strong light-harvesting ability and flexible tunability.However,the fluorescence signal of traditional SPs tends to quench in their aggregate states owing to the strongπ-πstacking,which can lead to the radiative decay pathway shutting down.To address this issue,aggregation-induced emission effect has been used as a rational tactic to boost the aggregate-state fluorescence of NIR-Ⅱemitters.In this contribution,we developed a precise molecular engineering tactic based on the block copolymerizations that integrate planar and twisted segments into one conjugated polymer backbone,providing great flexibility in tuning the photophysical properties and photothermal conversion capacity of SPs.Two monomers featured with twisted and planar architectures,respectively,were tactfully incorporated via a ternary copolymerization approach to produce a series of new SPs.The optimal copolymer(SP2)synchronously shows desirable absorption ability and good NIR-Ⅱquantum yield on the premise of maintaining typical aggregation-induced emission characteristics,resulting in balanced NIR-Ⅱfluorescence brightness and photothermal property.Water-dispersible nanoparticles fabricated from the optimal SP2 show efficient photothermal therapeutic effects both in vitro and in vivo.The in vivo investigation reveals the distinguished NIR-Ⅱfluorescence imaging performance of SP2 nanoparticles and their photothermal ablation toward tumor with prominent tumor accumulation ability and excellent biocompatibility.
基金supported in part by the National Natural Science Foundation of China(Grant No.81902372 for Ting Han,81502017 for Feng Jiao,81903062 for Meng Zhuo and 81572315 and 81874048 for Liwei Wang)the Innovation Group Project of Shanghai Municipal Health Commission(Grant No.2019CXJQ03 for Liwei Wang)+2 种基金the State Key Laboratory of Oncogenes and Related Genes(Grant No.90-17-06 for Liwei Wang)the Shanghai Leading Talents Project(Grant No.075 for Liwei Wang)the Shanghai Key Clinical Specialty(Grant No.2018 Oncology for Liwei Wang)。
文摘Objective:Pancreatic ductal adenocarcinoma(PDAC)is a disease with high mortality.Many so-called"junk"noncoding RNAs need to be discovered in PDAC.The purpose of this study was therefore to investigate the function and regulatory mechanism of the long noncoding RNA MEG3 in PDAC.Methods:The Gene Expression Omnibus database(GEO database)was used to determine the differential expression of long noncoding RNAs in PDAC,and MEG3 was selected for subsequent verification.Tissue and cell samples were used to verify MEG3 expression,followed by functional detection in vitro and in vivo.Microarrays were used to characterize long noncoding RNA and mRNA expression profiles.Competing endogenous RNA analyses were used to detect differential MEG3 and relational miRNA expression in PDAC.Finally,promoter analyses were conducted to explain the downregulation of MEG3 PDAC.Results:We generated a catalogue of PDAC-associated long noncoding RNAs in the GEO database.The ectopic expression of MEG3 inhibited PDAC growth and metastasis in vitro and in vivo,which was statistically significant(P<0.05).Microarray analysis showed that multiple microRNAs interacted with MEG3.We also showed that MEG3,as a competing endogenous RNA,directly sponged miR-374a-5p to regulate PTEN expression.The transcription factor,Sp1,recruited EZH2 and HDAC3 to the promoter and transcriptionally repressed MEG3 expression.Finally,clinical data showed that MEG3 and miR-374a-5p expressions were correlated with clinicopathological features.Statistically,Sp1,EZH2,HDAC3,and miR-374 a-5p were negatively correlated with MEG3(P<0.05).Conclusions:Reduced MEG3 levels played a crucial role in the PDAC malignant phenotype,which provided insight into novel and effective molecular targets of MEG3 for pancreatic cancer treatment.
基金Supported by the Department of Education of Zhejiang Province,No.Y201738451Health and Family Planning Commission of Zhejiang Province,No.2016148438
文摘BACKGROUND Pseudohypoparathyroidism type Ia(PHP Ia) is a rare hereditary syndrome, and patients with early PHP Ia are generally not diagnosed based on the presentation of cutaneous nodules as the main clinical feature. Here, we describe a Chinese boy with PHP Ia in whom the main clinical feature was cutaneous nodules, and the patient exhibited a novel GNAS mutation.CASE SUMMARY A 5-year-old boy presented with a 5-year history of cutaneous nodules scattered over his entire body. The patient had a short stature, round face, short neck, and slightly flattened nose;he also had multiple hard papules and cutaneous nodules scattered over his entire body. The patient had a significantly elevated parathyroid hormone level. His serum calcium level was reduced, while his serum phosphorus level was increased and his serum thyroid-stimulating hormone level was elevated. Skin biopsy showed osteoma cutis in subcutaneous tissue. Sanger sequencing revealed a frameshift mutation, c.399 del T(p.Ser133 Argfs*2) in exon 5 of the GNAS gene. The patient was diagnosed with PHP Ia and subclinical hypothyroidism. He was given 1,25-dihydroxyvitamin D,calcium carbonate, and synthetic L-thyroxine. After 3 months of treatment, the patient’s parathyroid hormone level decreased, and his serum calcium and serum phosphorus levels were normal. Moreover, his thyroid-stimulating hormone level decreased.CONCLUSION These findings can help dermatologists to diagnose PHP Ia in patients with cutaneous nodules as the main early clinical feature.
基金In-hospital Training Project of National Natural Science Foundation of China(04.03.19.153).
文摘[Objectives]To analyze the current research situation,hotspots and trends of curcumin and diabetes in recent 10 years.[Methods]Web of Science database was set as data source,the annual number of papers,the distribution of authors,the distribution of country/institution,the distribution of journals,the distribution of key words in the literature about curcumin and diabetes from January 1,2010 to March 31,2021 were quantitatively and visually analyzed with the aid of visualization software Bibliometrix.[Results]A total of 475 articles were included,and the annual number of papers was on the rise;the top three high-yielding countries were China(120 papers),India(65 papers),and the United States(58 papers).In terms of international cooperation,China and the United States had the most cooperation(27 papers);the top three high-yielding institutions were Wenzhou Medical University(42 papers),Mashhad University of Medical Sciences(41 papers)and Tehran University of Medical Sciences(30 papers);the most frequently cited authors were Wang Y(19 times),Li X(13 times),Li Y(12 times),Liang G(12 times)and Zhang Y(12 times);the top three journals in number of papers were Diabetology&Metabolic Syndrome(8 papers),PLoS One(8 papers),and European Journal of Pharmacology(7 papers),and the h index was 7,8,and 6,respectively;the most frequently cited journals were Diabetes(496 times),Journal of Biological Chemistry(486 times),PLoS One(347 times),Diabetes Care(284 times),and European Journal of Pharmacology(229 times);the most frequent key words mainly included oxidative stress,curcumin,insulin-resistance and expression;the hotspots were insulin resistance and NF-κB,mainly focusing on in vitro experiments.[Conclusions]The curcumin has good therapeutic potential in improving insulin resistance,inhibiting inflammation and oxidative stress,etc.The results are expected provide a reference and basis for scientific researchers to understand the current situation of curcumin and diabetes research and carry out the further research.
文摘. In this article, we describe the characteristics of large-scale modeling of the theme text of this site data and important progress in recent years. Topic modeling approach has attracted wide interest in the world, and promote a number of important data mining, development of computer vision and computational biology applications, including automatic text summaries, information retrieval, information recommendation, topic detection and tracking, natural scene understanding human action recognition and gene expression analysis. The main features of the model and the corresponding theme paper focuses on the text of this site data. Data with dynamic, high-end, multi-channel and distributed structure and the structure of the model is only part of the theme before modeling. The paper discussed in the framework of the unity of the three-dimensional Markov model of four structural features of the text of this site data modeling, and analysis of distributed computing and word combination of three-dimensional modeling topics Markov model and type fuzzy systems the possibility of applications. In addition to structural modeling for this site text data, also we discuss some of the three-dimensional Markov model energy minimization of machine learning algorithms.
文摘With Internet technology research and gradually used in modern distance education practice, high-bandwidth, high-speed, high-reliability remote education network will be able to provide better education services to create some more opportunities and possibilities. Multimedia courseware contains audio, video and other large-capacity information object, it has been widely used in practice of distance education, distance education and the overall quality of service has a greatly improved. However, due to the current courseware file size is very large, the user wants to browse the courseware, need to start on the site to download and then watch to play, if the change in the place of learning, we need to download again, very cumbersome and inefficient. In order to facilitate the user can at any time and place can conveniently browse online courseware streaming media technology came into being. Streaming media technology has been widely used in audio, video online play. Times for large data interaction design connotation and denotation, and development course contents and scope, we analyze and estimate the large interaction design trends in the information age of big data interaction design methods, processes, architectures, models and assessments, to explore a large design interactive design strategy and design details.
文摘Azadirachta indica A. Juss is a tropical evergreen plant, belonging to the Meliaceae family. The plant is used as folk medicines for the treatment of fever, neuromuscular pains, skin infections, diabetes and heart disease. Previous researches show that the plant possesses several types of chemical constituents and diverse biological activities. The paper concludes chemical constituents, biological activities and pesticide products of A. indica.
基金the National Natural Science Foundation of China(22271197)the Ministry of Science and Technology of China(2021YFA1501600)+5 种基金the Guangdong Basic and Applied Basic Research Foundation(2023A1515011578)the Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates(2019B030301003)the Shenzhen Science and Technology Program(RCYX20221008092924059,JCYJ20220531102601003)the Open Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates(2023B1212060003)the 2035 Research Excellence Program of Shenzhen University(2023c001)the Innovation and Technology Commission(ITC-CNERC14SCO1).
文摘Porous organic polymers(POPs)have attracted great attention in past decades.Although diverse functional POPs have been developed,multistimuli-responsive POPs with excellent aggregate-state luminescence together with good chiroptical properties have rarely been reported.Herein,two pairs of Salen-type enantiomeric PoPs with multistimuli-responsive luminescence and chiral features were designed and synthesized by facile polycondensation reactions between polyfunctional aggregation-induced emission luminogen(AlEgen)-containing salicylaldehyde derivatives and chiral diamines.With Salen units in polymer backbones as tetradentate ligands,a series of POP-metal complexes were further prepared.The obtained POPs and metal complexes show good porosity,high thermal stability,and obvious circular dichroism signals.Moreover,benefiting from the coexistence of AlEgen and Salen units in polymer structures,these POPs exhibit excellent luminescence performance in aggregate states and tunable fluorescence behaviors in response to external stimuli of Zn^(2+)ion,mechanical forces,organic solvent,and acids.Due to the dynamic feature of Schiff base C=N bonds,the present POPs can efficiently undergo hydrolysis reactions under strong acidic conditions to reproduce the AlEgencontaining monomers,and such an acid-induced degradation process can be directly visualized and dynamically monitored via fluorescence variation.These properties collectively make the POPs candidate materials for applications in heterogeneous asymmetric catalysis,fluorescence sensing,biomedicine,etc.
文摘Background:Very few studies have been conducted regarding the optimal time interval between hysteroscopic adhesiolysis and the embryo transfer(ET).Investigation of this optimal time may be helpful for assisted reproductive technology.Therefore,we investigated effects of the interval between hysteroscopic adhesiolysis and ET upon in vitro fertilization(IVF)cycle outcomes.Methods:Patients were recruited between January 2014 and September 2017 at the Reproductive Hospital Affiliated to Shandong University.Patients who were diagnosed with intra-uterine adhesion(IUA)and underwent hysteroscopic adhesiolysis before fresh IVF-ET or intra-cytoplasmic sperm injection cycles were classified into three groups according to the interval between hysteroscopic adhesiolysis and ET:less than 90 days(Group 1),90 to 180 days(Group 2),and greater than 180 days(Group 3).Baseline characteristics,controlled ovarian stimulation(COS)response,and pregnancy outcomes after ET were compared.Analysis of variance or non-parametric tests were used to test numerical data.The Pearson’s Chi-squared test was used to test categorical data.Results:A total of 312 patients were recruited as follows:112 in Group 1,137 in Group 2,and 63 in Group 3.There were no differences in baseline and COS characteristics among the three groups.The live-birth rate in Group 2(40.1%)was significantly higher than that in Group 1(17.9%;χ^2=14.545,P<0.001).There were no significant differences in the rates of biochemical,ongoing,and clinical pregnancy,and biochemical and clinical pregnancy abortion,as well as stillbirth among the groups.In the mild IUA patients,the live-birth rate was significantly higher in Group 2(42.6%)compared with Group 1(22%;χ^2=8.413,P=0.004).In the moderate IUA patients,Group 2(35.7%)had a higher frequency of live births than Group 1(6.7%;χ^2=8.187,P=0.004).Conclusions:The optimal waiting period for fresh ET after hysteroscopic adhesiolysis was 90 to 180 days in the current study.
基金supported by the Ministry of Science and Technology of China(Nos.2016YFC0202700,2016YFE0112200)the National Natural Science Foundation of China(Nos.21527814,91743202)the Marie Sklodowska-Curie Actions(No.H2020-MSCA-RISE-2015-690958)
文摘As the largest iron and steel producer in China, a part of Baosteel moved out of Shanghai deserves close attention due to its environmental impact. To understand the effect of Baosteel emission control on air quality in Shanghai, daily PM10, PM2.5, SO2, NO2 and CO were measured from 2010 to 2016. Concentrations of pollutants in Baoshan District presented a decreased trend during 2010-2016, with a reduction rate of 28.6% for PM10, 67.3% for SO2, 8.6% for NO2 and 42.0% for CO. However, fine particle pollution in Baoshan District during 2012-2016 seems to become more prominent, with PM2.5 concentration of 47 ± 28, 45 ± 33, 38 ± 24, 54 ± 41 and 51 ± 34 μg/m^3, respectively, indicating a slight increase of 8.5% in PM2.5. Concentrations of PM10 and CO decreased by 12.5% and 33.8% in the second half year in 2016 （compared with that in 2015） probably due to closure of blast furnace of Baosteel. Baosteel was identified as the largest pollution source in Baoshan District. Emission from Baosteel accounted for 58.0% of SO2, 43.6% of NO2 and 79.3% of dust in total emission from Baoshan District during 2010-2015. Meanwhile, pollutant emission and coal consumption from Baosteel decreased by 52.0% for SO2, 40.1% for NO2, 15.7% for dust and 22% for coal consumption. Energy consumption in Baoshan District reduced by 31% from 2011 to 2015. Air quality improvement in Shanghai was attributed to local emission reduction, together with regional air quality improvement.
基金supported by the National Natural Science Foundation of China(22271197,21905176)the Natural Science Foundation for Distinguished Young Scholars of Guangdong Province(2020B1515020011)+1 种基金the Science and Technology Plan of Shenzhen(JCYJ20190808142403590,JCYJ20190808153415062)the Instrumental Analysis Center of Shenzhen University。
文摘The development of new and efficient polymerization strategies for the synthesis of multisubstituted fused heterocyclic polymers with attractive properties is of great significance.Herein,a rhodium-catalyzed polyannulation route is developed for the in situ generation of multisubstituted polyquinolines with efficient aggregate-state fluorescence.Based on the cascade C-H activation of isonicotinamides and their annulations with internal diynes,a series of high molecular weight polyquinolines are efficiently produced in high yields of up to 99%in a facile and atom-economical manner.Unlike conventional two-component stepwise polymerizations,these polyannulation reactions are tolerant to monomer non-stoichiometric conditions and proceed even more thoroughly in the presence of an excess amount of the isonicotinamide monomer.Benefiting from the unique multisubstituted polyquinoline structures,the obtained polymers show high thermal and morphological stability,useful aggregation-induced emission(AIE)properties,and tunable aggregated-state fluorescence behaviors.The AIE-active polyquinoline is demonstrated to be a good lysosome-specific fluorescent probe with low cytotoxicity and excellent photostability.
基金National Natural Science Foundation of China,Grant/Award Number:22271197Science and Technology Plan of Shenzhen,Grant/Award Numbers:JCYJ20220531102601003,JCYJ20190808142403590。
文摘Functional materials with circularly polarized luminescence(CPL)have attracted tremendous attention due to their promising applications in three-dimensional dis-plays,chiral recognition and catalysis,photoelectronic devices,contrast imaging,information encryption,and otherfields.Among various CPL-active materials,poly-meric systems with aggregation-induced emission(AIE)have emerged as excellent candidates because of their efficient aggregate-statefluorescence,large solid-state dissymmetry factor,excellent processibility,diversified self-assembly behaviors,and readily switchable CPL properties.This review summarizes and discusses the recent progress as well as future perspective of diverse AIE polymer systems with CPL,including CPL-active covalent AIE polymers,CPL-active supramolecular AIE polymers,and AIEgen/polymer composites with CPL.According to the loca-tion or introduction method of AIEgen in polymer structures,this review further divides CPL-active covalent AIE polymers into three categories,including polymers with AIEgen in main chains,polymers with AIEgen in side chains,and CPL-active polymers with clusterization-triggered emission.CPL-active supramolecular AIE polymers are discussed based on the driving force for the formation of supramolecular polymers,including host–guest interactions,metal coordination,and other non-covalent interactions.Moreover,examples on the construction of CPL-active AIEgen/polymer composites by physically mixing AIEgens with chi-ral(supra)polymers are also presented.This review is anticipated to provide readers with an overall view on the design strategies of CPL-active AIE polymers,and facil-itate further research on the development of CPL materials and AIE polymers with advanced applications.
基金the Natural Science Foundation for Distinguished Young Scholars of Guangdong Province(2020B1515020011)the National Natural Science Foundation of China(21905176,21801169,21907068)+1 种基金the Science and Technology Plan of Shenzhen(JCYJ20190808142403590,JCYJ20190808121417291,JCYJ20190808153415062)the China Postdoctoral Science Foundation Grant(2019M663030,2019M653003).
文摘Aggregation-induced emission(AIE)refers to a photophysical effect that the luminescence of aggregates is stronger than that of the dispersed state.Since the concept of AIE was coined by Professor Ben Zhong Tang and co-workers in 2001,AIE has evolved from a simple luminescent phenomenon to a multidisciplinary research field with a widespread influence.It has changed people's way of thinking about chromophore aggregation and greatly promoted the development of advanced luminescent materials.During the 20-year development,diverse AIE luminogens(AlEgens)with attractive functionalities have been developed and remarkable achievements have been made in the mechanistic study and high-tech applications of AlEgens.In this review,we provide an overview of the historical development and representative achievements of AIE research.Perspectives on the application of AIE in aggregate science are also briefly discussed to guide the future development in this field.
基金the National Natural Science Foundation of China(Nos.21875152 and 21404077)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.17KJB150034)+3 种基金the Open Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates,Guangzhou 510640,China(South China University of Technology)(No.2019B030301003)the Priority Academic Program Development of Jiangsu High Education Institutions(PAPD).M.N.L.and Q.Z.Z.thank the financial support from Undergraduate Training Program for Innovation and Entrepreneurship,Soochow University(No.2018xj032)H.K.L.acknowledges the supports from Jiangsu Planned Projects for Postdoctoral Research Funds(No.1501023B)China Postdoctoral Science Foundation(No.2016M591906).
文摘Azide-alkyne click polymerization has become a powerful tool for polymer synthesis.However,the click polymerization between internal alkynes and azides is rarely utilized to prepare functional polymers.In this work,the polymerization reactions of activated internal alkyne monomers of tris(2-butynoate)s(1)with tetraphenylethene-containing diazides(2)were performed in dimethylformamide(DMF)under simple heating,affording four hyperbranched poly(methyltriazolylcarboxylate)s(hb-PMTCs)with high molecular weights(A4W up to 2.4 x 104)and regioregularities(up to 83.9%)in good yields.The hb-PMTCs are soluble in common organic solvents,and thermally stable with 5%weight loss temperatures up to 400℃.They are non-emissive in dilute solution,but become highly emissive in aggregated state,exhibiting aggregationinduced emission characteristics.The polymers can generate fluorescent photopatterns with high resolution,and can work as fluorescent sensors to detect nitroaromatic explosive with high sensitivity.
基金partially supported by the National Natural Science Foundation of China (Nos. 21875152 and 21404077)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No. 17KJB150034)+2 种基金the Priority Academic Program Development of Jiangsu High Education Institutions (PAPD)the financial supports from Jiangsu Planned Projects for Postdoctoral Research Funds (No. 1501023B)China Postdoctoral Science Foundation (No. 2016M591906)
文摘The copper-catalyzed and metal-free azide-alkyne click polymerizations have become efficient tools for polymer synthesis. However,the 1,3-dipolar polycycloadditions between internal alkynes and azides are rarely employed to construct functional polymers. Herein, the polycycloadditions of dibutynoate(1) and tetraphenylethene-containing diazides(2) were carried out at 100 °C for 12 h under solvent-and catalyst-free conditions, producing soluble poly(methyltriazolylcarboxylate)s(PMTCs) with high molecular weights in high yields. The resultant polymers were thermally stable with 5% weight loss temperatures up to 377 °C. The PMTCs showed aggregation-induced emission(AIE)properties. They could work as fluorescent sensors for detecting explosive with high sensitivity, and generate two-dimensional fluorescent photopatterns with high resolution. Furthermore, their triazolium salts could be utilized for cell-imaging applications.
基金fund by sub-project of National Science and Technology Major Project on Water Pollution Prevention and Control(No.2012ZX07203-003-Z04)supported by the Fundamental Research Funds for the Central Universities(No. ZYGX2012J112)
文摘AzoR is a homodimeric,flavin mononucleotide（FMN）-containing,NADH-dependent azoreductase from Escherichia coli.In this paper,we investigated the effect of the concentration of both AzoR and R59 G on the spectral behavior of the bound FMN using two-dimensional fluorescence correlation spectra.Two cross peaks（530,490） and（580,530） were observed from the dilution-induced 2D asynchronous correlation map of wt AzoR,while only one cross peak appeared at（600,530） for R59 C mutant.This result indicated that the mutation at site 59 influenced the formation of dilution-induced intermediates.The specific activity of both AzoR and R59 G mutant was unaffected by dilution when the enzyme concentration is below 1 μmol/L,which suggested that no significant dissociation of FMN occurred at low concentrations.Additionally,in order to explore the origin of these intermediates,we carried out a2 D correlation analysis using excitation wavelength-dependent fluorescence emission spectroscopy.The results showed that there coexisted two types of FMN that emitted fluorescence at 530 nm and 500 nm,respectively.Taken together,these results suggested that the 2D method is a very powerful method to identify the heterogeneous distribution of the bound FMN in solution.
