The demand for enhanced optical properties in advanced fluorescence technologies has driven research into the structure-property relationship of fluorophores.In this paper,we use naphthalene fluorophores Na DC-Aze and...The demand for enhanced optical properties in advanced fluorescence technologies has driven research into the structure-property relationship of fluorophores.In this paper,we use naphthalene fluorophores Na DC-Aze and PhDO-Aze as a case study to emphasize the pivotal role of cross conjugation in tuning the optical structure-property relationship.Na DC-Aze and PhDO-Aze,formed by hybridizing two distinct conjugated systems in a single naphthalene molecule,exhibit spectral characteristics from both conjugated systems.Experimental data and theoretical calculations demonstrate the coexistence of two electron-delocalization systems in a cross-conjugation manner in both Na DC-Aze and PhDO-Aze.The cross-conjugation fluorophores exhibit high brightness,large Stokes shift,and a broad absorption wavelength range by combining distinct spectral properties from its parent fluorophores.These spectral properties will be advantageous for certain applications(i.e.,panchromatic absorption in organic solar cells,and fluorophores compatible with a wide range of excitation wavelengths).展开更多
A comprehensive understanding of the relevance between molecular structure and passivation ability to screen efficient modifiers is essential for enhancing the performance of perovskite solar cells(PSCs).Here,three si...A comprehensive understanding of the relevance between molecular structure and passivation ability to screen efficient modifiers is essential for enhancing the performance of perovskite solar cells(PSCs).Here,three similarπ-πstacking molecules namely benzophenone(BPN),diphenyl sulfone(DPS),and diphenyl sulfoxide(DPSO)are used as back-interface modifiers in carbon-based CsPbBr_(3)PSCs.After investigation,the results demonstrate the positive effect of the p-πconjugation characteristic inπ-πstacking molecules on maximizing their passivation ability.The p-πco njugation of DPSO enables a higher coordinative activity of oxygen atom in its S=O group than that in 0=S=O group of DPS and C=O group of BPN,which gives a superior passivation effect of DPSO on defects of perovskite films.The modification of DPSO also significantly improves the p-type behavior of perovskite films and the back-interfacial energetics matching,inducing an increase of hole extraction and a decrease of energy loss.Finally,the unencapsulated carbon-based CsPbBr_(3)PSCs with DPSO achieve a maximum power conversion efficiency of 10.60%and outstanding long-term stability in high-temperature,high-humidity(85℃,85%relative humidity)air environment.This work provides insights into the influence of the structure ofπ-πstacking molecules on their ability to improve the perovskite films quality and therefore the PSCs performance.展开更多
Ciliates are eukaryotic unicellular organisms with complex morphology and developmental processes,including asexual and sexual processes.Conjugation is a form of sexual process that renews genetic materials.However,vi...Ciliates are eukaryotic unicellular organisms with complex morphology and developmental processes,including asexual and sexual processes.Conjugation is a form of sexual process that renews genetic materials.However,visualizing conjugation in ciliates is a challenge due to the complexity and dynamics of the process,while traditional staining methods are often insufficient for the research.This study introduces a new method for visualizing developmental progression in the nuclei during conjugation using Hoechst33342 staining.It describes how to proceed from cell culture,conjugation induction and synchronization,staining preparation,and observation to statistical analysis.The combination of fluorescent staining with the‘volume-fixing'technique eliminates the fixation and dehydration steps,thus reducing the overall operation time to just 20 minutes.This method offers several advantages over traditional staining techniques for studying the nuclei during conjugation.It improves image quality and workflow efficiency and enables real-time observation of live cell states.Potential solutions to challenges that may arise during experimental procedures are introduced and references and guidelines for cytological research are provided in this paper.展开更多
Immobilizing enzyme to nano interfaces has demonstrated to be a favorable strategy for prompting the industrialized application of enzyme.Despite tremendous endeavor has been devoted to using gold nanoparticles(AuNPs)...Immobilizing enzyme to nano interfaces has demonstrated to be a favorable strategy for prompting the industrialized application of enzyme.Despite tremendous endeavor has been devoted to using gold nanoparticles(AuNPs)as conjugation matrix due to its fascinating physico-chemical properties,maintaining enzymatic activity while circumventing cumbersome modification remains a formidable challenge.Herein,the freezing-directed conjugation of enzyme/nano interfaces was constructed without extra reagent.As the proof of concept,glucose oxidase(GOx)was chosen as model enzyme.The one-pot conjugation process can be facilely completed at−20°C under aqueous solution.Moreover,with the loading of GOx on AuNP at freezing,the enzyme exhibited superior catalytic activity and stability upon thermal and pH perturbation.The mechanism of boosted activity was then discussed in detail.It was found that higher loading density under freezing condition and more enzyme tending to bind AuNPs via Au-S bond were the main factors for the superior activity.More importantly,this methodology was universal and can also be applied to other enzyme which contains natural cysteine,such as horseradish peroxidase(HRP)and papain.This facile conjugation strategy accompanied by remarkable bioactivity expand the possibilities for enzymatic biosensing,microdevice and even drug delivery.展开更多
During conjugation of Paramecium caudatum, nuclear events occur in a scheduled program. Morphological studies on nuclear behavior during conjugation of P. caudatum have been performed since the end of the 19th century...During conjugation of Paramecium caudatum, nuclear events occur in a scheduled program. Morphological studies on nuclear behavior during conjugation of P. caudatum have been performed since the end of the 19th century. Here we report on new details concerning the conjugation of P. caudatum through the staining of conjugating ceils with protargol, carbol fuchsin solution, Hoechst 33342 and immunofluorescence labeling with monoclonal antibody of anti-a tubulin. 1） The crescent nucleus is a characteristic of the meiotic prophase of P. caudatum, has an unstained area. We stained this area with protargol, which was separated from the chromatin area and was not detected by the other stainings. 2） In regards to the four meiotic products, it has long been considered that only one product enters the paroral cone region （PC） and survives after meiosis. However, our protargol and immunofluorescence labeling results indicated that PC entrance of the meiotic product happened before the completion of meiosis instead of after. 3） In our previous study, protargol staining indicated the presence of a swollen structure around the central part of the ＂U＂ and ＂V＂ shaped spindles connecting the two types of prospective pronuclei. However, immunofluorescence labeling with anti-a tubulin antibodies gave a different image from protargol. All these observations form the basis for further studies of their molecular mechanisms.展开更多
After the third prezygotic division during conjugation of Paramecium caudatum,migratory and stationary pronuclei are produced.The migratory pronuclei remain in the paroral region tightly against the conjugating bounda...After the third prezygotic division during conjugation of Paramecium caudatum,migratory and stationary pronuclei are produced.The migratory pronuclei remain in the paroral region tightly against the conjugating boundaries;while the stationary pronuclei are located beside the migratory pronuclei.To date,however,it is not clear what causes this close side-by-side localization between migratory and stationary pronuclei.In the current study,immunofluorescence staining with monoclonal antibody of anti-α tubulin indicated that ＂U＂ or ＂V＂ shaped spindles connected the migratory and stationary pronuclei during the third prezygotic division.This observation accounts for the close localization between these two types of pronuclei.展开更多
RNA interference has been widely used for gene therapy of various infectious diseases and malignant tumors. However, its poor stability in serum has limited further clinic application. Here, we found that stability of...RNA interference has been widely used for gene therapy of various infectious diseases and malignant tumors. However, its poor stability in serum has limited further clinic application. Here, we found that stability of siRNA in serum enhanced obviously when 3′-terminus of sense strand （siRNA-pS） was conjugated with peptide, while same conjugation at 3′-terminus of antisense strand brought no such effects. And it was also found that only the peptide residue in siRNA-pS could be cut off by RNase A. All these results indicated that nucleases in serum prefer to invade siRNA duplex through the 3′-end of sense strand.展开更多
An efficient genetic transformation system and suitable promoters are essential prerequisites for gene expression studies and genetic engineering in streptomycetes.In this study,firstly,a genetic transformation system...An efficient genetic transformation system and suitable promoters are essential prerequisites for gene expression studies and genetic engineering in streptomycetes.In this study,firstly,a genetic transformation system based on intergeneric conjugation was developed in Streptomyces rimosus M527,a bacterial strain which exhibits strong antagonistic activity against a broad range of plant-pathogenic fungi.Some experimental parameters involved in this procedure were optimized,including the conjugative media,ratio of donor to recipient,heat shock temperature,and incubation time of mixed culture.Under the optimal conditions,a maximal conjugation frequency of 3.05^10-5 per recipie nt was obtai ned.Subseque ntly,based on the above developed and optimized tran sformati on system,the synthetic promoters SPL-21 and SPL-57,a native promoter potrB,and a constitutive promoter permE commonly used for gene expression in streptomycetes were selected and their activity was analyzed using gusA as a reporter gene in S.rimosus M527.Among the four tested promoters,SPL-21 exhibited the strongest expression activity and gave rise to a 2.2-fold increase in p-glucuronidase(GUS)activity compared with the control promoter permE.Promoter SPL-57 showed activity comparable to that of permE.Promoter potrB,which showed the lowest activity,showed a 50%decrease in GUS activity compared with the control permE.The transformation system developed in this study and the tested promotors provide a basis for the further modification of S.rimosus M527.展开更多
Unsymmetrical bisacridines(UAs) are a novel potent class of antitumor-active therapeutics.A significant route of phase II drug metabolism is conjugation with glutathione(GSH),which can be non-enzymatic and/or catalyze...Unsymmetrical bisacridines(UAs) are a novel potent class of antitumor-active therapeutics.A significant route of phase II drug metabolism is conjugation with glutathione(GSH),which can be non-enzymatic and/or catalyzed by GSH-dependent enzymes.The aim of this work was to investigate the GSHmediated metabolic pathway of a representative UA,C-2028.GSH-supplemented incubations of C-2028 with rat,but not with human,liver cytosol led to the formation of a single GSH-related metabolite.Interestingly,it was also revealed with rat liver microsomes.Its formation was NADPH-independent and was not inhibited by co-incubation with the cytochrome P450(CYP450) inhibitor 1-aminobenzotriazole.Therefore,the direct conjugation pathway occurred without the prior CYP450-catalyzed bioactivation of the substrate.In turn,incubations of C-2028 and GSH with human recombinant glutathione S-transferase(GST) P1-1 or with heat-/ethacrynic acid-inactivated liver cytosolic enzymes resulted in the presence or lack of GSH conjugated form,respectively.These findings proved the necessary participation of GST in the initial activation of the GSH thiol group to enable a nucleophilic attack on the substrate molecule.Another C-2028-GSH S-conjugate was also formed during non-enzymatic reaction.Both GSH S-conjugates were characterized by combined liquid chromatography/tandem mass spectrometry.Mechanisms for their formation were proposed.The ability of C-2028 to GST-mediated and/or direct GSH conjugation is suspected to be clinically important.This may affect the patient’s drug clearance due to GST activity,loss of GSH,or the interactions with GSH-conjugated drugs.Moreover,GST-mediated depletion of cellular GSH may increase tumor cell exposure to reactive products of UA metabolic transformations.展开更多
Improvements in the diagnosis and treatment of cancer are urgently needed for use in nanotechnology.Nanoparticles(NPs)can reduce the side effects of traditional chemotherapy by sustained release of loaded drugs and in...Improvements in the diagnosis and treatment of cancer are urgently needed for use in nanotechnology.Nanoparticles(NPs)can reduce the side effects of traditional chemotherapy by sustained release of loaded drugs and increase therapeutic efficiency.NPs can also enhance endothelial permeation retention by size effect and its accumulation in tumor cells through passive targeting.Furthermore,it is critical to treat cancer with a controlled targeted drug which can be specifically delivered into tumor cells and released there,resulting in a targeted therapy to eradicate tumor cells while sparing normal cells.To this end,antibody-mediated targeting therapy has been developed,but imperfections in antibodies(Abs)limit this therapy.Therefore,the combination of NPs and Abs has been highly valued in recent years,because conjugating special Abs on the surface of NPs can increase targeting efficiency,enabling selective delivery of anti-cancer drugs to tumor cells.In this mini-review,we would like to enumerate the strategies for the conjugation of Abs to the surface of the NPs as well as the precise engineering of targeted NPs.The application of targeting antibody fragments in this drug delivery system will also be discussed.展开更多
An optically active monomer containing azobenzene moieties with chiral group (s-2-methyl-butyl), 4-[2-(methacryloyloxy)ethyloxy] -4'-(s-2-methyl-1-butyloxycarbonyl) azobenzene (M1) was synthesized. Polymer (PM1) p...An optically active monomer containing azobenzene moieties with chiral group (s-2-methyl-butyl), 4-[2-(methacryloyloxy)ethyloxy] -4'-(s-2-methyl-1-butyloxycarbonyl) azobenzene (M1) was synthesized. Polymer (PM1) possessing optical phase conjugated response was obtained by homopolymerization of the optically active monomer (M1) using free radical polymerization. The polymer was very soluble in common solvents and good optical quality films could be easily fabricated by spin coating. The optical phase conjugated responses of the polymer PM1 were measured by degenerate four-wave mixing (DFWM). In comparison with polymer containing no chiral group, it was found from the preliminary measurement of photoisomeric change that optical phase conjugated response of the PM1 in the long-range order hexagonal symmetry microstructure could be easily controlled by choosing the appropriate polarization direction of the irradiating beams (514.5 nm) and the irradiating number, presumably due to the chiral group in the PM1 molecular structure. For the case of the polymer investigated here, a chiral group side chain was introduced to increase optical phase conjugated response intensity with different polarization directions of the irradiating beams, which aims originally at searching for a new photoactive material.展开更多
The phase conjugation between the deformable mirror and the wavefront sensor in the aberration correction of a terawatt Ti：sapphire laser is studied experimentally and theoretically in this paper. At varying values o...The phase conjugation between the deformable mirror and the wavefront sensor in the aberration correction of a terawatt Ti：sapphire laser is studied experimentally and theoretically in this paper. At varying values of phase- conjugation precision, we focus the corresponding beams into spots of the same size of 5.1 μm × 5.3 μm with a f/4 parabola in the 32 TW/36 fs Ti：sapphire laser system. The results show that the precision of conjugation can induce an intensity modulation but does not significantly affect the wavefront correction.展开更多
Random mutagenesis is commonly used to study gene function. The screening of mutants exhibiting specific pheno- types assists in the identification of phenotype-related genes. In the current study, we isolated Antarct...Random mutagenesis is commonly used to study gene function. The screening of mutants exhibiting specific pheno- types assists in the identification of phenotype-related genes. In the current study, we isolated Antarctic bacteria, and developed a transposon Tn5 mutagenesis system. A total of 26 strains were isolated from seawater and freshwater near Antarctic King Sejong Research Station, King George Island. Six Psychrobacter strains were identified as psychrophilic, with optimal growth tempera- tures of 10~C or 15~C Psychrobacter cryohalolentis PAMC 21807 with a high growth rate at 4~C was selected for transposon mutagenesis. Tri-parental conjugation with a plasmid containing Tn5 produced 13 putative recombinants containing the selectable marker. Genomic Southern hybridization confirmed Tn5 existed as episomes for seven recombinants, and for a single recombinant, Tn5 was integrated into the genome of Psychrobacter cryohalolentis PAMC 21807. The result indicates that the mutagenesis method, although successful, has a relatively low rate. The psychrophilic bacteria isolated in this study may be a useful resource for studying cold adaptation mechanisms, and the mutagenesis method can be applied to genetic analysis.展开更多
In this paper, we consider 2 × 2 non-cooperative elliptic system involving Laplace operator defined on bounded, continuous and strictly Lipschitz domain of Rn. First we prove the existence and uniqueness for the ...In this paper, we consider 2 × 2 non-cooperative elliptic system involving Laplace operator defined on bounded, continuous and strictly Lipschitz domain of Rn. First we prove the existence and uniqueness for the state of the system under conjugation conditions;then we discuss the existence of the optimal control of boundary type with Neumann conditions, and we find the set of equations and inequalities that characterize it.展开更多
Through-space conjugated molecules are interesting building blocks for the construction of functional materials that allow multi-dimensional transport of carrier and energy.However,the well explored through-space conj...Through-space conjugated molecules are interesting building blocks for the construction of functional materials that allow multi-dimensional transport of carrier and energy.However,the well explored through-space conjugated molecules are quite limited,which defers their structure-property correlation establishment and wide-scale application.In this review,we introduce a kind of newly-emerging folded tetraphenylethene derivatives featuring through-space conjugation.Their synthesis,crystal and electronic structures,and optical properties are described,and their representative applications as bipolar charge-transporting materials in organic light-emitting diodes and as single-molecule wires in molecular devices are presented,which are anticipated to provide guidance for the further expansion of through-space conjugated systems.展开更多
The stability issue is one of the key factors hindering the commercial application of organic solar cells.All-polymer organic solar cell is one of the effective ways to solve the stability problem.In this work,we desi...The stability issue is one of the key factors hindering the commercial application of organic solar cells.All-polymer organic solar cell is one of the effective ways to solve the stability problem.In this work,we designed and synthesized two polymer donor materials PBDT and PDTBDT with different conjugation ranges,and demonstrated for the first time that extending the conjugation range of donor materials in all polymer solar cells can significantly improve device efficiency and stability.The experimental results of materials and devices show that PDTBDT with a larger conjugation range has stronger crystallinity and a more planar structure,which endows the active layer in its corresponding device with higher exciton dissociation probability,lower carrier recombination probability,more balanced charge transport properties and more favorable film morphology.As a result,the PDTBDT:PYF-T-o devices display an outstanding PCE of 13.38%,which is much higher than PBDT with smaller conjugation range based devices.Moreover,the PDTBDT:PYF-T-o device retains 0.86 of the initial PCE after over 500 h in the air atmosphere,exhibiting significantly improved stability.The improved stability is attributed to the enhanced moisture and air tolerance of active layer film thanks to the strong crystallinity of the donor material.These results demonstrate that the conjugation expansion strategy is one of the effective ways to obtain efficient and stable all-polymer organic solar cells.展开更多
Adjusting the electronic structure of graphitic carbon nitride(g-C_(3)N_(4))photocatalyst throughπ-πconju-gation is an effective method to achieve efficient photogenerated carrier separation.One key challenge ofπ-...Adjusting the electronic structure of graphitic carbon nitride(g-C_(3)N_(4))photocatalyst throughπ-πconju-gation is an effective method to achieve efficient photogenerated carrier separation.One key challenge ofπ-πconjugation control is to tune the degree of such conjugation without destroying the g-C_(3)N_(4)struc-ture.Herein we report a conceptual design that achieves a coplanar heterojunction by enhancing theπ-πconjugation via the doping of crystalline g-C_(3)N_(4)using a conjugated double bond ring molecule,1,3,5-benzenetriol,during calcination process.The selection of the dopant enables the facile creation of a unique coplanar heterojunction which not only retains the pristine network structure of g-C_(3)N_(4),but remarkably promotes separation and transfer of photogenerated carriers through the enhancedπ-conjugated endogenous electric field.As a result,the new g-C_(3)N_(4)photocatalyst efficiently photocatalyti-cally produces hydrogen from water under visible light irradiation with a high H 2 production rate up to 94.94μmol/h,and a notable external quantum efficiency of 16.4%at 420 nm.展开更多
Discrete H ∞ control theory were obtained by conjugation,chain scattering representation and (J,J′) lossless factorization.The existence of the solution is equivalent to the existence of two positive s...Discrete H ∞ control theory were obtained by conjugation,chain scattering representation and (J,J′) lossless factorization.The existence of the solution is equivalent to the existence of two positive solutions of two Riccati equations.展开更多
For every partition and its conjugation , there is an important invariant , which denotes the number of different parts. That is , . We will derive a series of symmetric q-identities from the invariant in partition co...For every partition and its conjugation , there is an important invariant , which denotes the number of different parts. That is , . We will derive a series of symmetric q-identities from the invariant in partition conjugation by studying modified Durfee rectangles. The extensive applications of the several symmetric q-identities in q-series ?[1] will also be discussed. Without too much effort one can obtain much well-known knowledge as well as new formulas by proper substitutions and elementary calculations, such as symmetric identities, mock theta functions, a two-variable reciprocity theorem, identities from Ramanujan’s Lost Notebook and so on.展开更多
The existence and uniqueness of the state for 2 × 2 Dirichlet cooperative elliptic systems under conjugation conditions are proved using Lax-Milgram lemma, then the boundary control for these systems is discussed...The existence and uniqueness of the state for 2 × 2 Dirichlet cooperative elliptic systems under conjugation conditions are proved using Lax-Milgram lemma, then the boundary control for these systems is discussed. The set of equations and inequalities that characterizes this boundary control is found by theory of Lions, Sergienko and Deineka. The problem for cooperative Neumann elliptic systems under conjugation conditions is also considered. Finally, the problem for n × n cooperative elliptic systems under conjugation conditions is established.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22225806,22078314,21908216,22378385)Dalian Institute of Chemical Physics(Nos.DICPI202142,DICPI202436)+1 种基金Agency for Science,Technology and Research(No.A*STAR,Singapore)under its Advanced Manufacturing and Engineering Program(No.A2083c0051)SUTD Kickstarter Initiative(No.SKI 2021_03_10)。
文摘The demand for enhanced optical properties in advanced fluorescence technologies has driven research into the structure-property relationship of fluorophores.In this paper,we use naphthalene fluorophores Na DC-Aze and PhDO-Aze as a case study to emphasize the pivotal role of cross conjugation in tuning the optical structure-property relationship.Na DC-Aze and PhDO-Aze,formed by hybridizing two distinct conjugated systems in a single naphthalene molecule,exhibit spectral characteristics from both conjugated systems.Experimental data and theoretical calculations demonstrate the coexistence of two electron-delocalization systems in a cross-conjugation manner in both Na DC-Aze and PhDO-Aze.The cross-conjugation fluorophores exhibit high brightness,large Stokes shift,and a broad absorption wavelength range by combining distinct spectral properties from its parent fluorophores.These spectral properties will be advantageous for certain applications(i.e.,panchromatic absorption in organic solar cells,and fluorophores compatible with a wide range of excitation wavelengths).
基金financial supports from the Natural Science Foundation of Shandong Province(ZR2021ME037)the National Natural Science Foundation of China(52472259,22179051 and 61604143)+2 种基金the National Key Research and Development Program of China(2021YFE0111000)the Special Fund of Taishan Scholar Program of Shandong Province(tsqnz20221141)the Foundation of Key Laboratory of Advanced Technique&Preparation for Renewable Energy Materials,Ministry of Education,Yunnan Normal University(OF2022-02)。
文摘A comprehensive understanding of the relevance between molecular structure and passivation ability to screen efficient modifiers is essential for enhancing the performance of perovskite solar cells(PSCs).Here,three similarπ-πstacking molecules namely benzophenone(BPN),diphenyl sulfone(DPS),and diphenyl sulfoxide(DPSO)are used as back-interface modifiers in carbon-based CsPbBr_(3)PSCs.After investigation,the results demonstrate the positive effect of the p-πconjugation characteristic inπ-πstacking molecules on maximizing their passivation ability.The p-πco njugation of DPSO enables a higher coordinative activity of oxygen atom in its S=O group than that in 0=S=O group of DPS and C=O group of BPN,which gives a superior passivation effect of DPSO on defects of perovskite films.The modification of DPSO also significantly improves the p-type behavior of perovskite films and the back-interfacial energetics matching,inducing an increase of hole extraction and a decrease of energy loss.Finally,the unencapsulated carbon-based CsPbBr_(3)PSCs with DPSO achieve a maximum power conversion efficiency of 10.60%and outstanding long-term stability in high-temperature,high-humidity(85℃,85%relative humidity)air environment.This work provides insights into the influence of the structure ofπ-πstacking molecules on their ability to improve the perovskite films quality and therefore the PSCs performance.
基金supported by the National Natural Science Foundation of China(No.32270558)。
文摘Ciliates are eukaryotic unicellular organisms with complex morphology and developmental processes,including asexual and sexual processes.Conjugation is a form of sexual process that renews genetic materials.However,visualizing conjugation in ciliates is a challenge due to the complexity and dynamics of the process,while traditional staining methods are often insufficient for the research.This study introduces a new method for visualizing developmental progression in the nuclei during conjugation using Hoechst33342 staining.It describes how to proceed from cell culture,conjugation induction and synchronization,staining preparation,and observation to statistical analysis.The combination of fluorescent staining with the‘volume-fixing'technique eliminates the fixation and dehydration steps,thus reducing the overall operation time to just 20 minutes.This method offers several advantages over traditional staining techniques for studying the nuclei during conjugation.It improves image quality and workflow efficiency and enables real-time observation of live cell states.Potential solutions to challenges that may arise during experimental procedures are introduced and references and guidelines for cytological research are provided in this paper.
基金the National Natural Science Foundation of China(Nos.32001782 and 22222402)the Natural Science Foundation of Hunan Province(No.2021JJ40564)+2 种基金Changsha Municipal Natural Science Foundation(No.kq2007021)the Opening Foundation of State Key Laboratory of Chemo/Biosensing and Chemometrics,Hunan University(No.2019013)Open Project of State Key Laboratory of Supramolecular Structure and Materials(No.sklssm2023016).
文摘Immobilizing enzyme to nano interfaces has demonstrated to be a favorable strategy for prompting the industrialized application of enzyme.Despite tremendous endeavor has been devoted to using gold nanoparticles(AuNPs)as conjugation matrix due to its fascinating physico-chemical properties,maintaining enzymatic activity while circumventing cumbersome modification remains a formidable challenge.Herein,the freezing-directed conjugation of enzyme/nano interfaces was constructed without extra reagent.As the proof of concept,glucose oxidase(GOx)was chosen as model enzyme.The one-pot conjugation process can be facilely completed at−20°C under aqueous solution.Moreover,with the loading of GOx on AuNP at freezing,the enzyme exhibited superior catalytic activity and stability upon thermal and pH perturbation.The mechanism of boosted activity was then discussed in detail.It was found that higher loading density under freezing condition and more enzyme tending to bind AuNPs via Au-S bond were the main factors for the superior activity.More importantly,this methodology was universal and can also be applied to other enzyme which contains natural cysteine,such as horseradish peroxidase(HRP)and papain.This facile conjugation strategy accompanied by remarkable bioactivity expand the possibilities for enzymatic biosensing,microdevice and even drug delivery.
文摘During conjugation of Paramecium caudatum, nuclear events occur in a scheduled program. Morphological studies on nuclear behavior during conjugation of P. caudatum have been performed since the end of the 19th century. Here we report on new details concerning the conjugation of P. caudatum through the staining of conjugating ceils with protargol, carbol fuchsin solution, Hoechst 33342 and immunofluorescence labeling with monoclonal antibody of anti-a tubulin. 1） The crescent nucleus is a characteristic of the meiotic prophase of P. caudatum, has an unstained area. We stained this area with protargol, which was separated from the chromatin area and was not detected by the other stainings. 2） In regards to the four meiotic products, it has long been considered that only one product enters the paroral cone region （PC） and survives after meiosis. However, our protargol and immunofluorescence labeling results indicated that PC entrance of the meiotic product happened before the completion of meiosis instead of after. 3） In our previous study, protargol staining indicated the presence of a swollen structure around the central part of the ＂U＂ and ＂V＂ shaped spindles connecting the two types of prospective pronuclei. However, immunofluorescence labeling with anti-a tubulin antibodies gave a different image from protargol. All these observations form the basis for further studies of their molecular mechanisms.
文摘After the third prezygotic division during conjugation of Paramecium caudatum,migratory and stationary pronuclei are produced.The migratory pronuclei remain in the paroral region tightly against the conjugating boundaries;while the stationary pronuclei are located beside the migratory pronuclei.To date,however,it is not clear what causes this close side-by-side localization between migratory and stationary pronuclei.In the current study,immunofluorescence staining with monoclonal antibody of anti-α tubulin indicated that ＂U＂ or ＂V＂ shaped spindles connected the migratory and stationary pronuclei during the third prezygotic division.This observation accounts for the close localization between these two types of pronuclei.
基金Ministry of Science and Technology of China(Grant No.2012CB720604)National Natural Science Foundation of China(Grant No.20932001)
文摘RNA interference has been widely used for gene therapy of various infectious diseases and malignant tumors. However, its poor stability in serum has limited further clinic application. Here, we found that stability of siRNA in serum enhanced obviously when 3′-terminus of sense strand （siRNA-pS） was conjugated with peptide, while same conjugation at 3′-terminus of antisense strand brought no such effects. And it was also found that only the peptide residue in siRNA-pS could be cut off by RNase A. All these results indicated that nucleases in serum prefer to invade siRNA duplex through the 3′-end of sense strand.
基金Project supported by the National Natural Science Foundation of China(Nos.31772213 and 31972320)the Excellent Youth Fund of Zhejiang Province,China(No.LR17C140002)
文摘An efficient genetic transformation system and suitable promoters are essential prerequisites for gene expression studies and genetic engineering in streptomycetes.In this study,firstly,a genetic transformation system based on intergeneric conjugation was developed in Streptomyces rimosus M527,a bacterial strain which exhibits strong antagonistic activity against a broad range of plant-pathogenic fungi.Some experimental parameters involved in this procedure were optimized,including the conjugative media,ratio of donor to recipient,heat shock temperature,and incubation time of mixed culture.Under the optimal conditions,a maximal conjugation frequency of 3.05^10-5 per recipie nt was obtai ned.Subseque ntly,based on the above developed and optimized tran sformati on system,the synthetic promoters SPL-21 and SPL-57,a native promoter potrB,and a constitutive promoter permE commonly used for gene expression in streptomycetes were selected and their activity was analyzed using gusA as a reporter gene in S.rimosus M527.Among the four tested promoters,SPL-21 exhibited the strongest expression activity and gave rise to a 2.2-fold increase in p-glucuronidase(GUS)activity compared with the control promoter permE.Promoter SPL-57 showed activity comparable to that of permE.Promoter potrB,which showed the lowest activity,showed a 50%decrease in GUS activity compared with the control permE.The transformation system developed in this study and the tested promotors provide a basis for the further modification of S.rimosus M527.
文摘Unsymmetrical bisacridines(UAs) are a novel potent class of antitumor-active therapeutics.A significant route of phase II drug metabolism is conjugation with glutathione(GSH),which can be non-enzymatic and/or catalyzed by GSH-dependent enzymes.The aim of this work was to investigate the GSHmediated metabolic pathway of a representative UA,C-2028.GSH-supplemented incubations of C-2028 with rat,but not with human,liver cytosol led to the formation of a single GSH-related metabolite.Interestingly,it was also revealed with rat liver microsomes.Its formation was NADPH-independent and was not inhibited by co-incubation with the cytochrome P450(CYP450) inhibitor 1-aminobenzotriazole.Therefore,the direct conjugation pathway occurred without the prior CYP450-catalyzed bioactivation of the substrate.In turn,incubations of C-2028 and GSH with human recombinant glutathione S-transferase(GST) P1-1 or with heat-/ethacrynic acid-inactivated liver cytosolic enzymes resulted in the presence or lack of GSH conjugated form,respectively.These findings proved the necessary participation of GST in the initial activation of the GSH thiol group to enable a nucleophilic attack on the substrate molecule.Another C-2028-GSH S-conjugate was also formed during non-enzymatic reaction.Both GSH S-conjugates were characterized by combined liquid chromatography/tandem mass spectrometry.Mechanisms for their formation were proposed.The ability of C-2028 to GST-mediated and/or direct GSH conjugation is suspected to be clinically important.This may affect the patient’s drug clearance due to GST activity,loss of GSH,or the interactions with GSH-conjugated drugs.Moreover,GST-mediated depletion of cellular GSH may increase tumor cell exposure to reactive products of UA metabolic transformations.
基金This work was supported by the National Natural Science Foundation of China(No.81601589 and 81672216)the Academic Newcomer Award of Huazhong University of Science and Technology(2017).
文摘Improvements in the diagnosis and treatment of cancer are urgently needed for use in nanotechnology.Nanoparticles(NPs)can reduce the side effects of traditional chemotherapy by sustained release of loaded drugs and increase therapeutic efficiency.NPs can also enhance endothelial permeation retention by size effect and its accumulation in tumor cells through passive targeting.Furthermore,it is critical to treat cancer with a controlled targeted drug which can be specifically delivered into tumor cells and released there,resulting in a targeted therapy to eradicate tumor cells while sparing normal cells.To this end,antibody-mediated targeting therapy has been developed,but imperfections in antibodies(Abs)limit this therapy.Therefore,the combination of NPs and Abs has been highly valued in recent years,because conjugating special Abs on the surface of NPs can increase targeting efficiency,enabling selective delivery of anti-cancer drugs to tumor cells.In this mini-review,we would like to enumerate the strategies for the conjugation of Abs to the surface of the NPs as well as the precise engineering of targeted NPs.The application of targeting antibody fragments in this drug delivery system will also be discussed.
基金This work was supported by National Natural Science Foundation of China (No. 59873001)Scientific Foundation for Returned Overseas Chinese Scholars, Ministry of Education.
文摘An optically active monomer containing azobenzene moieties with chiral group (s-2-methyl-butyl), 4-[2-(methacryloyloxy)ethyloxy] -4'-(s-2-methyl-1-butyloxycarbonyl) azobenzene (M1) was synthesized. Polymer (PM1) possessing optical phase conjugated response was obtained by homopolymerization of the optically active monomer (M1) using free radical polymerization. The polymer was very soluble in common solvents and good optical quality films could be easily fabricated by spin coating. The optical phase conjugated responses of the polymer PM1 were measured by degenerate four-wave mixing (DFWM). In comparison with polymer containing no chiral group, it was found from the preliminary measurement of photoisomeric change that optical phase conjugated response of the PM1 in the long-range order hexagonal symmetry microstructure could be easily controlled by choosing the appropriate polarization direction of the irradiating beams (514.5 nm) and the irradiating number, presumably due to the chiral group in the PM1 molecular structure. For the case of the polymer investigated here, a chiral group side chain was introduced to increase optical phase conjugated response intensity with different polarization directions of the irradiating beams, which aims originally at searching for a new photoactive material.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB808101)the National Natural Science Foundation of China(Grant No.60921004)
文摘The phase conjugation between the deformable mirror and the wavefront sensor in the aberration correction of a terawatt Ti：sapphire laser is studied experimentally and theoretically in this paper. At varying values of phase- conjugation precision, we focus the corresponding beams into spots of the same size of 5.1 μm × 5.3 μm with a f/4 parabola in the 32 TW/36 fs Ti：sapphire laser system. The results show that the precision of conjugation can induce an intensity modulation but does not significantly affect the wavefront correction.
基金supported by the Korea Polar Research Institute(Grant nos.PE08050 and PE13240)
文摘Random mutagenesis is commonly used to study gene function. The screening of mutants exhibiting specific pheno- types assists in the identification of phenotype-related genes. In the current study, we isolated Antarctic bacteria, and developed a transposon Tn5 mutagenesis system. A total of 26 strains were isolated from seawater and freshwater near Antarctic King Sejong Research Station, King George Island. Six Psychrobacter strains were identified as psychrophilic, with optimal growth tempera- tures of 10~C or 15~C Psychrobacter cryohalolentis PAMC 21807 with a high growth rate at 4~C was selected for transposon mutagenesis. Tri-parental conjugation with a plasmid containing Tn5 produced 13 putative recombinants containing the selectable marker. Genomic Southern hybridization confirmed Tn5 existed as episomes for seven recombinants, and for a single recombinant, Tn5 was integrated into the genome of Psychrobacter cryohalolentis PAMC 21807. The result indicates that the mutagenesis method, although successful, has a relatively low rate. The psychrophilic bacteria isolated in this study may be a useful resource for studying cold adaptation mechanisms, and the mutagenesis method can be applied to genetic analysis.
文摘In this paper, we consider 2 × 2 non-cooperative elliptic system involving Laplace operator defined on bounded, continuous and strictly Lipschitz domain of Rn. First we prove the existence and uniqueness for the state of the system under conjugation conditions;then we discuss the existence of the optimal control of boundary type with Neumann conditions, and we find the set of equations and inequalities that characterize it.
基金the financial support from the National Natural Science Foundation of China(No.51273053)the National Basic Research Program of China(973 Program,Nos.2015CB655004 and 2013CB834702)+5 种基金the Guangdong Natural Science Funds for Distinguished Young Scholar(No.2014A030306035)the Guangdong Innovative Research Team Program of China(No.201101C0105067115)the Science and Technology Project of Guangdong Province(No.2016B090907001)the ITC-CNERC14S01,the Fundamental Research Funds for the Central Universities(Nos.2015PT020 and 2015ZY013)the Natural Science Foundation of Guangdong Province(No.2016A030312002)the National Undergraduate Innovative and Entrepreneurial Training Program(No.201410561032)
文摘Through-space conjugated molecules are interesting building blocks for the construction of functional materials that allow multi-dimensional transport of carrier and energy.However,the well explored through-space conjugated molecules are quite limited,which defers their structure-property correlation establishment and wide-scale application.In this review,we introduce a kind of newly-emerging folded tetraphenylethene derivatives featuring through-space conjugation.Their synthesis,crystal and electronic structures,and optical properties are described,and their representative applications as bipolar charge-transporting materials in organic light-emitting diodes and as single-molecule wires in molecular devices are presented,which are anticipated to provide guidance for the further expansion of through-space conjugated systems.
基金We acknowledge financial support provided by the National Natural Science Foundation of China(Nos.21822503 and 51973043)the and the CAS-CSIRO Joint Project of Chinese Academy of Sciences(No.121E32KYSB20190021).
文摘The stability issue is one of the key factors hindering the commercial application of organic solar cells.All-polymer organic solar cell is one of the effective ways to solve the stability problem.In this work,we designed and synthesized two polymer donor materials PBDT and PDTBDT with different conjugation ranges,and demonstrated for the first time that extending the conjugation range of donor materials in all polymer solar cells can significantly improve device efficiency and stability.The experimental results of materials and devices show that PDTBDT with a larger conjugation range has stronger crystallinity and a more planar structure,which endows the active layer in its corresponding device with higher exciton dissociation probability,lower carrier recombination probability,more balanced charge transport properties and more favorable film morphology.As a result,the PDTBDT:PYF-T-o devices display an outstanding PCE of 13.38%,which is much higher than PBDT with smaller conjugation range based devices.Moreover,the PDTBDT:PYF-T-o device retains 0.86 of the initial PCE after over 500 h in the air atmosphere,exhibiting significantly improved stability.The improved stability is attributed to the enhanced moisture and air tolerance of active layer film thanks to the strong crystallinity of the donor material.These results demonstrate that the conjugation expansion strategy is one of the effective ways to obtain efficient and stable all-polymer organic solar cells.
基金supported by the National Natural Science Foundation of China (Nos. U1862105, 22078256)Natural Science Basic Research Plan in Shaanxi Province of China (Nos. 2017JZ001, 2018KJXX-008)+2 种基金Fundamental Research Funds for the Central Universities (No. cxtd2017004)K.C. Wong Education Foundation, Hong Kong, Chinafinancial support from Australian Research Council are appreciated
文摘Adjusting the electronic structure of graphitic carbon nitride(g-C_(3)N_(4))photocatalyst throughπ-πconju-gation is an effective method to achieve efficient photogenerated carrier separation.One key challenge ofπ-πconjugation control is to tune the degree of such conjugation without destroying the g-C_(3)N_(4)struc-ture.Herein we report a conceptual design that achieves a coplanar heterojunction by enhancing theπ-πconjugation via the doping of crystalline g-C_(3)N_(4)using a conjugated double bond ring molecule,1,3,5-benzenetriol,during calcination process.The selection of the dopant enables the facile creation of a unique coplanar heterojunction which not only retains the pristine network structure of g-C_(3)N_(4),but remarkably promotes separation and transfer of photogenerated carriers through the enhancedπ-conjugated endogenous electric field.As a result,the new g-C_(3)N_(4)photocatalyst efficiently photocatalyti-cally produces hydrogen from water under visible light irradiation with a high H 2 production rate up to 94.94μmol/h,and a notable external quantum efficiency of 16.4%at 420 nm.
文摘Discrete H ∞ control theory were obtained by conjugation,chain scattering representation and (J,J′) lossless factorization.The existence of the solution is equivalent to the existence of two positive solutions of two Riccati equations.
文摘For every partition and its conjugation , there is an important invariant , which denotes the number of different parts. That is , . We will derive a series of symmetric q-identities from the invariant in partition conjugation by studying modified Durfee rectangles. The extensive applications of the several symmetric q-identities in q-series ?[1] will also be discussed. Without too much effort one can obtain much well-known knowledge as well as new formulas by proper substitutions and elementary calculations, such as symmetric identities, mock theta functions, a two-variable reciprocity theorem, identities from Ramanujan’s Lost Notebook and so on.
文摘The existence and uniqueness of the state for 2 × 2 Dirichlet cooperative elliptic systems under conjugation conditions are proved using Lax-Milgram lemma, then the boundary control for these systems is discussed. The set of equations and inequalities that characterizes this boundary control is found by theory of Lions, Sergienko and Deineka. The problem for cooperative Neumann elliptic systems under conjugation conditions is also considered. Finally, the problem for n × n cooperative elliptic systems under conjugation conditions is established.
