In order to reduce the risk of non-performing loans, losses, and improve the loan approval efficiency, it is necessary to establish an intelligent loan risk and approval prediction system. A hybrid deep learning model...In order to reduce the risk of non-performing loans, losses, and improve the loan approval efficiency, it is necessary to establish an intelligent loan risk and approval prediction system. A hybrid deep learning model with 1DCNN-attention network and the enhanced preprocessing techniques is proposed for loan approval prediction. Our proposed model consists of the enhanced data preprocessing and stacking of multiple hybrid modules. Initially, the enhanced data preprocessing techniques using a combination of methods such as standardization, SMOTE oversampling, feature construction, recursive feature elimination (RFE), information value (IV) and principal component analysis (PCA), which not only eliminates the effects of data jitter and non-equilibrium, but also removes redundant features while improving the representation of features. Subsequently, a hybrid module that combines a 1DCNN with an attention mechanism is proposed to extract local and global spatio-temporal features. Finally, the comprehensive experiments conducted validate that the proposed model surpasses state-of-the-art baseline models across various performance metrics, including accuracy, precision, recall, F1 score, and AUC. Our proposed model helps to automate the loan approval process and provides scientific guidance to financial institutions for loan risk control.展开更多
Objective:CD8+T cells are the key effector cells in the anti-tumor immune response.The mechanism underlying the infiltration of CD8+T cells in esophageal squamous cell carcinoma(ESCC)has not been clearly elucidated.Me...Objective:CD8+T cells are the key effector cells in the anti-tumor immune response.The mechanism underlying the infiltration of CD8+T cells in esophageal squamous cell carcinoma(ESCC)has not been clearly elucidated.Methods:Fresh ESCC tissues were collected and grouped according to the infiltration density of CD8+T cells.After the transcriptome sequencing on these samples and the combined analyses with The Cancer Genome Atlas(TCGA)ESCC data,a secreted protein DEFB1 was selected to explore its potential role in the infiltration of CD8+T cells.Bioinformatics analyses,histological verification and in vitro experiments were then performed.Results:DEFB1 was highly expressed in ESCC,and the high expression of DEFB1 was an independent risk factor for overall survival.Since the up-regulation or down-regulation of DEFB1 did not affect the proliferation,migration and apoptosis of ESCC cells,we speculated that the oncogenic effect of DEFB1 was achieved by regulating microenvironmental characteristics.Bioinformatics analyses suggested that DEFB1 might play a major role in the inflammatory response and anti-tumor immune response,and correlate to the infiltration of immature dendritic cell(imDC)in ESCC.Histological analyses further confirmed that there were less CD8+T cells infiltrated,less CD83+mature DC(mDC)infiltrated and more CD1a+imDC infiltrated in those ESCC samples with high expression of DEFB1.After the treatment with recombinant DEFB1 protein,the maturation of DC was hindered significantly,followed by the impairment of the killing effects of T cells in both 2D and 3D culture in vitro.Conclusions:Tumor-derived DEFB1 can inhibit the maturation of DC and weaken the function of CD8+T cells,accounting for the immune tolerance in ESCC.The role of DEFB1 in ESCC deserves further exploration.展开更多
Optical excitations of the hybrids,which are assembled by coupling single-walled carbon nanotubes(SWCNTs)with organic molecules through van der Waals interactions,are studied using ab initio manybody Green’s function...Optical excitations of the hybrids,which are assembled by coupling single-walled carbon nanotubes(SWCNTs)with organic molecules through van der Waals interactions,are studied using ab initio manybody Green’s function theory.We take the semiconducting(7,0)SWCNT,the squarylium and oligothiophene molecules as the example.The E11 and E22 absorption peaks of the(7,0)tube can be redshifted by tens of meV.Most importantly,the lowest dark exciton of the(7,0)tube at the lower-energy side of E11 can be brightened by the interaction between the nanotube and molecules.Position of this new satellite absorption peak is influenced by the type of adsorbed molecule.These findings may be useful for tuning the emission energy and emission efficiency of CNTs.展开更多
Focused on the cultivation of the craftsmanship spirit in the teaching process of the basic courses, the thesis analysis how to integrate the connotation of the craftsmanship spirit into the teaching of practical writ...Focused on the cultivation of the craftsmanship spirit in the teaching process of the basic courses, the thesis analysis how to integrate the connotation of the craftsmanship spirit into the teaching of practical writing. By the use of comparative analysis, case studies, transposition evaluation and other methods, it illustrates the vital importance of the craftsmanship spirit in students' practical writing, their future study, work and life, and also demonstrates how to foster their ingenuity.展开更多
In a previous paper[Phys.Rev.A95,060701(R)(2017)],we demonstrated that a new type of two-body interaction,which depends on the center of mass(CoM)momentum,can be realized for ultracold atoms via laser-modulated magnet...In a previous paper[Phys.Rev.A95,060701(R)(2017)],we demonstrated that a new type of two-body interaction,which depends on the center of mass(CoM)momentum,can be realized for ultracold atoms via laser-modulated magnetic Feshbach resonance(MFR).Further studies(e.g.L He et al,Phys.Rev.Lett.120,045302(2018))show that various interesting phenomena,such as Fulde–Ferrell superfluids,can be induced by scattering between ultracold atoms with this interaction.In this work we investigate the shallow bound states of two ultracold atoms with this type of interaction.We show that when the magnetic field B is below the MFR point B0,two shallow bound states can appear in this system.Namely,a'two-component dimer'or a dimer with pseudo-spin 1/2 can be formed by two atoms.Furthermore,the dispersion curve of the dimer may have either single or double minimums in the CoM momentum space.The latter case can be explained as a result from significant pseudo-spin-orbital coupling(SOC)effects.Our results show that the ultracold gases with CoM momentum dependent interaction may be a candidate for quantum simulations with ultracold two-component molecules,especially the molecule gases with SOC.展开更多
The eikonal approximation(EA)is widely used in various high-energy scattering problems.In this work we generalize this approximation from the scattering problems with time-independent Hamiltonian to the ones with peri...The eikonal approximation(EA)is widely used in various high-energy scattering problems.In this work we generalize this approximation from the scattering problems with time-independent Hamiltonian to the ones with periodical Hamiltonians,i.e.,the Floquet scattering problems.We further illustrate the applicability of our generalized EA via the scattering problem with respect to a shaking spherical square-well potential,by comparing the results given by this approximation and the exact ones.The generalized EA we developed is helpful for the research of manipulation of high-energy scattering processes with external field,e.g.the manipulation of atom,molecule or nuclear collisions or reactions via strong laser fields.展开更多
Osteoarthritis(OA)is the most common disabling joint disease with no effective disease modifying drugs.Extracellular vesicles released by several types of mesenchymal stem cells could promote cartilage repair and amel...Osteoarthritis(OA)is the most common disabling joint disease with no effective disease modifying drugs.Extracellular vesicles released by several types of mesenchymal stem cells could promote cartilage repair and ameliorate OA pathology in animal models,representing a novel therapeutic strategy.In this study,we demonstrated that extracellular vesicles derived from human umbilical cord mesenchymal stem cells(hUC-EVs)could maintain chondrocyte homeostasis and alleviate OA,and further revealed a novel molecular mechanism of this therapeutic effect.miR-223,which could directly bind with the 3′UTR of NLRP3 mRNA,was found to be a key miRNA for hUC-EVs to exert beneficial effects on inflammation inhibiting and cartilage protecting.For enhancing the effect on mitigating osteoarthritis,exogenous miR-223 was loaded into hUC-EVs by electroporation,and a collagen II-targeting peptide(WYRGRL)was modified onto the surface of hUC-EVs by genetic engineering to achieve a more targeted and efficient RNA delivery to the cartilage.The dual-engineered EVs showed a maximal effect on inhibiting the NLRP3 inflammasome activation and chondrocyte pyroptosis,and offered excellent results for the treatment of OA.This study provides a novel theoretical basis and a promising therapeutic strategy for the application of engineered extracellular vesicles in OA treatment.展开更多
Recent studies have demonstrated that cancer-associated adipocytes (CAAs) in the tumor microenvironment are involved in the malignant progression of breast cancer. However, the underlying mechanism of CAA formation an...Recent studies have demonstrated that cancer-associated adipocytes (CAAs) in the tumor microenvironment are involved in the malignant progression of breast cancer. However, the underlying mechanism of CAA formation and its effects on the development of breast cancer are still unknown. Here, we show that CSF2 is highly expressed in both CAAs and breast cancer cells. CSF2 promotes inflammatory phenotypic changes of adipocytes through the Stat3 signaling pathway, leading to the secretion of multiple cytokines and proteases, particularly C–X–C motif chemokine ligand 3 (CXCL3). Adipocyte-derived CXCL3 binds to its specific receptor CXCR2 on breast cancer cells and activates the FAK pathway, enhancing the mesenchymal phenotype, migration, and invasion of breast cancer cells. In addition, a combination treatment targeting CSF2 and CXCR2 shows a synergistic inhibitory effect on adipocyte-induced lung metastasis of mouse 4T1 cells in vivo. These findings elucidate a novel mechanism of breast cancer metastasis and provide a potential therapeutic strategy for breast cancer metastasis.展开更多
In order to overcome the trade-off between the strength and electrical conductivity of aluminum alloy conductors,the new Al-Ce-Sc,Al-Ce-Y,Al-Ce-Zr and Al-Ce-Sc-Y alloys were prepared by die casting,high temperature ho...In order to overcome the trade-off between the strength and electrical conductivity of aluminum alloy conductors,the new Al-Ce-Sc,Al-Ce-Y,Al-Ce-Zr and Al-Ce-Sc-Y alloys were prepared by die casting,high temperature homogenization treatment,hot extrusion and cold drawing.Adding Sc and Y eliminated the dendrite segregation of the as-cast Al-0.2 Ce alloy and promoted the formation of equiaxed grains with the average grain size of 142.5μm.The Al-0.2 Ce-0.2 Sc-0.1 Y alloy inherited the great tensile properties of Al-0.2 Ce-0.2 Sc alloy and the high electrical conductivity of Al-0.2 Ce-0.1 Y alloy simultaneously.After cold drawing and annealing at 200℃for 5 h,the ultimate tensile strength of Al-0.2 Ce-0.2 Sc-0.1 Y alloy reached 200 MPa and 198 MPa,the elongation reached 6.8%and 8.5%,and the electrical conductivity reached 61.01%and 61.77%,respectively.The main second phase of Al-0.2 Ce-0.2 Sc-0.1 Y alloy after hot extrusion were Al_(13)Fe_3 Ce containing a few Y and Si atoms.The larger size and proportion of the second phase greatly reduced the concentration of solute Fe and Si atoms and the addition of Y significantly decreased the density of defects after cold drawing compared to Al-0.2 Ce-0.2 Sc alloy,which improved electrical conductivity of the alloy.Furthermore,the dispersed and coherent nano-size Al_3 Sc precipitions of Al-0.2 Ce-0.2 Sc-0.1 Y alloy greatly improved strength,elongation and heat resistance.Compared with Al-0.2 Ce-0.2 Sc alloy,the lower density of dislocation,stacking fault and subgrain boundary and the larger size of Al_3 Sc precipitions with enrichment of Y atoms enable the Al-0.2 Ce-0.2 Sc-0.1 Y alloy to maintain high strength,elongation and electrical conductivity after annealing.展开更多
Mineralization catalyzed by carbonic anhydrase(CA)is one of the most promising technologies for capturing CO_(2).In this work,Escherichia coli BL21(DE3)was used as the host,and the N-terminus of ice nucleation protein...Mineralization catalyzed by carbonic anhydrase(CA)is one of the most promising technologies for capturing CO_(2).In this work,Escherichia coli BL21(DE3)was used as the host,and the N-terminus of ice nucleation protein(INPN)was used as the carrier protein.Different fusion patterns and vectors were used to construct CA surface display systems forα-carbonic anhydrase(HPCA)from Helicobacter pylori 26695 andα-carbonic anhydrase(SazCA)from Sulfurihydrogenibium azorense.The surface display system in which HPCA was fused with INPN via a flexible linker and intermediate repeat sequences showed higher whole-cell enzyme activity,while the enzyme activity of the SazCA expression system was significantly higher than that of the HPCA expression system.The pET22b vector with the signal peptide PelB was more suitable for the cell surface display of SazCA.Cell frac-tionation and western-blot analysis indicated that SazCA and INPN were successfully anchored on the cell’s outer membrane as a fusion protein.The enzyme activity of the surface display strain E-22b-I RL S(11.43 U⋅mL^(−1) OD 600−1)was significantly higher than that of the intracellular expression strain E-22b-S(8.355 U⋅mL^(−1) OD 600−1)under optimized induction conditions.Compared with free SazCA,E-22b-I RL S had higher thermal and pH stability.The long-term stability of SazCA was also significantly improved by surface display.When the engineered strain and free enzyme were used for CO_(2) mineralization,the amount of CaCO_(3) deposition catalyzed by the strain E-22b-I RL S on the surface(241 mg)was similar to that of the free SazCA and was significantly higher than the intracellular expression strain E-22b-S(173 mg).These results demonstrate that the SazCA surface display strain can serve as a whole-cell biocatalyst for CO_(2) capture and mineralization.展开更多
文摘In order to reduce the risk of non-performing loans, losses, and improve the loan approval efficiency, it is necessary to establish an intelligent loan risk and approval prediction system. A hybrid deep learning model with 1DCNN-attention network and the enhanced preprocessing techniques is proposed for loan approval prediction. Our proposed model consists of the enhanced data preprocessing and stacking of multiple hybrid modules. Initially, the enhanced data preprocessing techniques using a combination of methods such as standardization, SMOTE oversampling, feature construction, recursive feature elimination (RFE), information value (IV) and principal component analysis (PCA), which not only eliminates the effects of data jitter and non-equilibrium, but also removes redundant features while improving the representation of features. Subsequently, a hybrid module that combines a 1DCNN with an attention mechanism is proposed to extract local and global spatio-temporal features. Finally, the comprehensive experiments conducted validate that the proposed model surpasses state-of-the-art baseline models across various performance metrics, including accuracy, precision, recall, F1 score, and AUC. Our proposed model helps to automate the loan approval process and provides scientific guidance to financial institutions for loan risk control.
基金supported by the National Natural Science Foundation of China(No.81972681,82103677)Tianjin Education Commission Research Plan Project(No.2021KJ201)+1 种基金Shenzhen High-level Hospital Construction Fund(No.G2022139)Tianjin Key Medical Discipline(Specialty)Construction Project(No.TJYXZDXK-009A).
文摘Objective:CD8+T cells are the key effector cells in the anti-tumor immune response.The mechanism underlying the infiltration of CD8+T cells in esophageal squamous cell carcinoma(ESCC)has not been clearly elucidated.Methods:Fresh ESCC tissues were collected and grouped according to the infiltration density of CD8+T cells.After the transcriptome sequencing on these samples and the combined analyses with The Cancer Genome Atlas(TCGA)ESCC data,a secreted protein DEFB1 was selected to explore its potential role in the infiltration of CD8+T cells.Bioinformatics analyses,histological verification and in vitro experiments were then performed.Results:DEFB1 was highly expressed in ESCC,and the high expression of DEFB1 was an independent risk factor for overall survival.Since the up-regulation or down-regulation of DEFB1 did not affect the proliferation,migration and apoptosis of ESCC cells,we speculated that the oncogenic effect of DEFB1 was achieved by regulating microenvironmental characteristics.Bioinformatics analyses suggested that DEFB1 might play a major role in the inflammatory response and anti-tumor immune response,and correlate to the infiltration of immature dendritic cell(imDC)in ESCC.Histological analyses further confirmed that there were less CD8+T cells infiltrated,less CD83+mature DC(mDC)infiltrated and more CD1a+imDC infiltrated in those ESCC samples with high expression of DEFB1.After the treatment with recombinant DEFB1 protein,the maturation of DC was hindered significantly,followed by the impairment of the killing effects of T cells in both 2D and 3D culture in vitro.Conclusions:Tumor-derived DEFB1 can inhibit the maturation of DC and weaken the function of CD8+T cells,accounting for the immune tolerance in ESCC.The role of DEFB1 in ESCC deserves further exploration.
基金supported by the National Natural Science Foundation of China(No.21833004)。
文摘Optical excitations of the hybrids,which are assembled by coupling single-walled carbon nanotubes(SWCNTs)with organic molecules through van der Waals interactions,are studied using ab initio manybody Green’s function theory.We take the semiconducting(7,0)SWCNT,the squarylium and oligothiophene molecules as the example.The E11 and E22 absorption peaks of the(7,0)tube can be redshifted by tens of meV.Most importantly,the lowest dark exciton of the(7,0)tube at the lower-energy side of E11 can be brightened by the interaction between the nanotube and molecules.Position of this new satellite absorption peak is influenced by the type of adsorbed molecule.These findings may be useful for tuning the emission energy and emission efficiency of CNTs.
文摘Focused on the cultivation of the craftsmanship spirit in the teaching process of the basic courses, the thesis analysis how to integrate the connotation of the craftsmanship spirit into the teaching of practical writing. By the use of comparative analysis, case studies, transposition evaluation and other methods, it illustrates the vital importance of the craftsmanship spirit in students' practical writing, their future study, work and life, and also demonstrates how to foster their ingenuity.
基金supported by the National Key Research and Development Program of China (Grant No. 2022YFA1405300)the National Safety Academic Fund (Grant No. U1930201)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China (22XNH100)
文摘In a previous paper[Phys.Rev.A95,060701(R)(2017)],we demonstrated that a new type of two-body interaction,which depends on the center of mass(CoM)momentum,can be realized for ultracold atoms via laser-modulated magnetic Feshbach resonance(MFR).Further studies(e.g.L He et al,Phys.Rev.Lett.120,045302(2018))show that various interesting phenomena,such as Fulde–Ferrell superfluids,can be induced by scattering between ultracold atoms with this interaction.In this work we investigate the shallow bound states of two ultracold atoms with this type of interaction.We show that when the magnetic field B is below the MFR point B0,two shallow bound states can appear in this system.Namely,a'two-component dimer'or a dimer with pseudo-spin 1/2 can be formed by two atoms.Furthermore,the dispersion curve of the dimer may have either single or double minimums in the CoM momentum space.The latter case can be explained as a result from significant pseudo-spin-orbital coupling(SOC)effects.Our results show that the ultracold gases with CoM momentum dependent interaction may be a candidate for quantum simulations with ultracold two-component molecules,especially the molecule gases with SOC.
基金supported by the National Key Research and Development Program of China (Grant No.2022YFA1405300)the Innovation Program for Quantum Science and Technology (Grant No.2023ZD0300700)。
文摘The eikonal approximation(EA)is widely used in various high-energy scattering problems.In this work we generalize this approximation from the scattering problems with time-independent Hamiltonian to the ones with periodical Hamiltonians,i.e.,the Floquet scattering problems.We further illustrate the applicability of our generalized EA via the scattering problem with respect to a shaking spherical square-well potential,by comparing the results given by this approximation and the exact ones.The generalized EA we developed is helpful for the research of manipulation of high-energy scattering processes with external field,e.g.the manipulation of atom,molecule or nuclear collisions or reactions via strong laser fields.
基金the Key Project of National Natural Science Foundation of China(81830076)the National Natural Science Foundation of China(82272568)+1 种基金the Shanghai Engineering Technology Research Center and Professional Technology Service Platform project of 2020“Science and Technology Innovation Action Plan”of Shanghai(20DZ2254100)the Biomedical Technology Support Special Project of Shanghai 2021“Science and Technology Innovation Action Plan”(21S31902300).
文摘Osteoarthritis(OA)is the most common disabling joint disease with no effective disease modifying drugs.Extracellular vesicles released by several types of mesenchymal stem cells could promote cartilage repair and ameliorate OA pathology in animal models,representing a novel therapeutic strategy.In this study,we demonstrated that extracellular vesicles derived from human umbilical cord mesenchymal stem cells(hUC-EVs)could maintain chondrocyte homeostasis and alleviate OA,and further revealed a novel molecular mechanism of this therapeutic effect.miR-223,which could directly bind with the 3′UTR of NLRP3 mRNA,was found to be a key miRNA for hUC-EVs to exert beneficial effects on inflammation inhibiting and cartilage protecting.For enhancing the effect on mitigating osteoarthritis,exogenous miR-223 was loaded into hUC-EVs by electroporation,and a collagen II-targeting peptide(WYRGRL)was modified onto the surface of hUC-EVs by genetic engineering to achieve a more targeted and efficient RNA delivery to the cartilage.The dual-engineered EVs showed a maximal effect on inhibiting the NLRP3 inflammasome activation and chondrocyte pyroptosis,and offered excellent results for the treatment of OA.This study provides a novel theoretical basis and a promising therapeutic strategy for the application of engineered extracellular vesicles in OA treatment.
基金supported by grants from the National Natural Science Foundation of China(NSFC)(82260531 and 81760509)the Natural Science Foundation of Jiangxi Province of China(20181BAB205043 and 20224BAB206057)to X.X.
文摘Recent studies have demonstrated that cancer-associated adipocytes (CAAs) in the tumor microenvironment are involved in the malignant progression of breast cancer. However, the underlying mechanism of CAA formation and its effects on the development of breast cancer are still unknown. Here, we show that CSF2 is highly expressed in both CAAs and breast cancer cells. CSF2 promotes inflammatory phenotypic changes of adipocytes through the Stat3 signaling pathway, leading to the secretion of multiple cytokines and proteases, particularly C–X–C motif chemokine ligand 3 (CXCL3). Adipocyte-derived CXCL3 binds to its specific receptor CXCR2 on breast cancer cells and activates the FAK pathway, enhancing the mesenchymal phenotype, migration, and invasion of breast cancer cells. In addition, a combination treatment targeting CSF2 and CXCR2 shows a synergistic inhibitory effect on adipocyte-induced lung metastasis of mouse 4T1 cells in vivo. These findings elucidate a novel mechanism of breast cancer metastasis and provide a potential therapeutic strategy for breast cancer metastasis.
基金supported financially by the Key Research and Development Program of Guangdong Province(NO.2020B010186002)the Science and Technology Major Project of Hunan Province(NO.2017GK4002)。
文摘In order to overcome the trade-off between the strength and electrical conductivity of aluminum alloy conductors,the new Al-Ce-Sc,Al-Ce-Y,Al-Ce-Zr and Al-Ce-Sc-Y alloys were prepared by die casting,high temperature homogenization treatment,hot extrusion and cold drawing.Adding Sc and Y eliminated the dendrite segregation of the as-cast Al-0.2 Ce alloy and promoted the formation of equiaxed grains with the average grain size of 142.5μm.The Al-0.2 Ce-0.2 Sc-0.1 Y alloy inherited the great tensile properties of Al-0.2 Ce-0.2 Sc alloy and the high electrical conductivity of Al-0.2 Ce-0.1 Y alloy simultaneously.After cold drawing and annealing at 200℃for 5 h,the ultimate tensile strength of Al-0.2 Ce-0.2 Sc-0.1 Y alloy reached 200 MPa and 198 MPa,the elongation reached 6.8%and 8.5%,and the electrical conductivity reached 61.01%and 61.77%,respectively.The main second phase of Al-0.2 Ce-0.2 Sc-0.1 Y alloy after hot extrusion were Al_(13)Fe_3 Ce containing a few Y and Si atoms.The larger size and proportion of the second phase greatly reduced the concentration of solute Fe and Si atoms and the addition of Y significantly decreased the density of defects after cold drawing compared to Al-0.2 Ce-0.2 Sc alloy,which improved electrical conductivity of the alloy.Furthermore,the dispersed and coherent nano-size Al_3 Sc precipitions of Al-0.2 Ce-0.2 Sc-0.1 Y alloy greatly improved strength,elongation and heat resistance.Compared with Al-0.2 Ce-0.2 Sc alloy,the lower density of dislocation,stacking fault and subgrain boundary and the larger size of Al_3 Sc precipitions with enrichment of Y atoms enable the Al-0.2 Ce-0.2 Sc-0.1 Y alloy to maintain high strength,elongation and electrical conductivity after annealing.
基金the financial support provided by the National Key Research and Development Program of China(Project No.2018YFA0902100)the National Natural Science Foundation of China(No.22178262,No.21576197).
文摘Mineralization catalyzed by carbonic anhydrase(CA)is one of the most promising technologies for capturing CO_(2).In this work,Escherichia coli BL21(DE3)was used as the host,and the N-terminus of ice nucleation protein(INPN)was used as the carrier protein.Different fusion patterns and vectors were used to construct CA surface display systems forα-carbonic anhydrase(HPCA)from Helicobacter pylori 26695 andα-carbonic anhydrase(SazCA)from Sulfurihydrogenibium azorense.The surface display system in which HPCA was fused with INPN via a flexible linker and intermediate repeat sequences showed higher whole-cell enzyme activity,while the enzyme activity of the SazCA expression system was significantly higher than that of the HPCA expression system.The pET22b vector with the signal peptide PelB was more suitable for the cell surface display of SazCA.Cell frac-tionation and western-blot analysis indicated that SazCA and INPN were successfully anchored on the cell’s outer membrane as a fusion protein.The enzyme activity of the surface display strain E-22b-I RL S(11.43 U⋅mL^(−1) OD 600−1)was significantly higher than that of the intracellular expression strain E-22b-S(8.355 U⋅mL^(−1) OD 600−1)under optimized induction conditions.Compared with free SazCA,E-22b-I RL S had higher thermal and pH stability.The long-term stability of SazCA was also significantly improved by surface display.When the engineered strain and free enzyme were used for CO_(2) mineralization,the amount of CaCO_(3) deposition catalyzed by the strain E-22b-I RL S on the surface(241 mg)was similar to that of the free SazCA and was significantly higher than the intracellular expression strain E-22b-S(173 mg).These results demonstrate that the SazCA surface display strain can serve as a whole-cell biocatalyst for CO_(2) capture and mineralization.
