Titanium dioxide(TiO_(2))has attracted considerable research attentions for its promising applications in solar cells and photocatalytic devices.However,the intrinsic challenge lies in the relatively low energy conver...Titanium dioxide(TiO_(2))has attracted considerable research attentions for its promising applications in solar cells and photocatalytic devices.However,the intrinsic challenge lies in the relatively low energy conversion efficiency of TiO_(2),primarily attributed to the substantial band gaps(exceeding 3.0 eV)associated with its rutile and anatase phases.Leveraging multi-objective global optimization,we have identified two quasi-layered ternary Ti-O-S crystals,composed of titanium,oxygen,and sulfur.The calculations of formation energy,phonon dispersions,and thermal stability confirm the chemical,dynamical and thermal stability of these newly discovered phases.Employing the state-of-art hybrid density functional approach and many-body perturbation theory(quasiparticle GW approach and Bethe-Salpeter equation),we calculate the optical properties of both the TiOS phases.Significantly,both phases show favorable photocatalytic characteristics,featuring band gaps suitable for visible optical absorption and appropriate band alignments with water for effective charge carrier separation.Therefore,ternary compound TiOS holds the potential for achieving high-efficiency photochemical conversion,showing our multi-objective global optimization provides a new approach for novel environmental and energy materials design with multicomponent compounds.展开更多
The choices of proper dopants and doping sites significantly influence the doping efficiency.In this work,using doping in Al N as an example,we discuss how to choose dopants and doping sites in semiconductors to creat...The choices of proper dopants and doping sites significantly influence the doping efficiency.In this work,using doping in Al N as an example,we discuss how to choose dopants and doping sites in semiconductors to create shallow defect levels.By comparing the defect properties of C_(N),O_(N),Mg_(Al),and Si_(Al)in AlN and analyzing the pros and cons of different doping approaches from the aspects of size mismatch between dopant and host elements,electronegativity difference and perturbation to the band edge states after the substitution,we propose that Mg_(Al)and Si_(Al)should be the best dopants and doping sites for p-type and n-type doping,respectively.Further first-principles calculations verify our predictions as these defects present lower formation energies and shallower defect levels.The defect charge distributions also show that the band edge states,which mainly consist of N-s and p orbitals,are less perturbed when Al is substituted,therefore,the derived defect states turn out to be delocalized,opposite to the situation when N is substituted.This approach of analyzing the band structure of the host material and choosing dopants and doping sites to minimize the perturbation on the host band structure is general and can provide reliable estimations for finding shallow defect levels in semiconductors.展开更多
BACKGROUND Abnormal expression patterns of mucin 2(MUC2)have been reported in a variety of malignant tumors and precancerous lesions.Reduced MUC2 expression in the intestinal mucosa,caused by various pathogenic factor...BACKGROUND Abnormal expression patterns of mucin 2(MUC2)have been reported in a variety of malignant tumors and precancerous lesions.Reduced MUC2 expression in the intestinal mucosa,caused by various pathogenic factors,is related to mechanical dysfunction of the intestinal mucosa barrier and increased intestinal mucosal permeability.However,the relationship between MUC2 and the intestinal mucosal barrier in patients with colorectal cancer(CRC)is not clear.AIM To explore the relationship between MUC2 and intestinal mucosal barrier by characterizing the multiple expression patterns of MUC2 in CRC.METHODS Immunohistochemical staining was performed on intestinal tissue specimens from 100 CRC patients,including both cancer tissues and adjacent normal tissues.Enzyme-linked immunosorbent assays were performed on preoperative sera from 66 CRC patients and 20 normal sera to detect the serum levels of MUC2,diamine oxide(DAO),and D-lactate(D-LAC).The relationship between MUC2 expression and clinical parameters was calculated by theχ2 test or Fisher’s exact test.Prognostic value of MUC2 was evaluated by Kaplan-Meier curve and log-rank tests.RESULTS Immunohistochemical staining of 100 CRC tissues showed that the expression of MUC2 in cancer tissues was lower than that in normal tissues(54%vs 79%,P<0.05),and it was correlated with tumor-node-metastasis(TNM)stage and lymph node metastasis in CRC patients(P<0.05).However,the serum level of MUC2 in CRC patients was higher than that in normal controls,and was positively associated with serum levels of human DAO(χ2=3.957,P<0.05)and D-LAC(χ^(2)=7.236,P<0.05),which are the biomarkers of the functional status of the intestinal mucosal barrier.And the serum level of MUC2 was correlated with TNM stage,tumor type,and distant metastasis in CRC patients(P<0.05).Kaplan-Meier curves showed that decreased MUC2 expression in CRC tissues predicted a poor survival.CONCLUSION MUC2 in tissues may play a protective role by participating in the intestinal mucosal barrier and can be used as an indicator to evaluate the prognosis of CRC patients.展开更多
基金Project supported by the Natural Science Foundation of WIUCAS (Grant Nos.WIUCASQD2023004 and WIUCASQD2022025)the National Natural Science Foundation of China (Grant Nos.12304006,12104452,12022508,12074394,and 12374061)+1 种基金the Shanghai Science and Technology Innovation Action Plan (Grant No.23JC1401400)the Natural Science Foundation of Wenzhou (Grant No.L2023005)。
文摘Titanium dioxide(TiO_(2))has attracted considerable research attentions for its promising applications in solar cells and photocatalytic devices.However,the intrinsic challenge lies in the relatively low energy conversion efficiency of TiO_(2),primarily attributed to the substantial band gaps(exceeding 3.0 eV)associated with its rutile and anatase phases.Leveraging multi-objective global optimization,we have identified two quasi-layered ternary Ti-O-S crystals,composed of titanium,oxygen,and sulfur.The calculations of formation energy,phonon dispersions,and thermal stability confirm the chemical,dynamical and thermal stability of these newly discovered phases.Employing the state-of-art hybrid density functional approach and many-body perturbation theory(quasiparticle GW approach and Bethe-Salpeter equation),we calculate the optical properties of both the TiOS phases.Significantly,both phases show favorable photocatalytic characteristics,featuring band gaps suitable for visible optical absorption and appropriate band alignments with water for effective charge carrier separation.Therefore,ternary compound TiOS holds the potential for achieving high-efficiency photochemical conversion,showing our multi-objective global optimization provides a new approach for novel environmental and energy materials design with multicomponent compounds.
基金supported by the National Natural Science Foundation of China(Grants No.11991060,No.12088101,No.U2230402,and No.12304006)the Natural Science Foundation of WIUCAS(Grants No.WIUCASQD2023004)。
文摘The choices of proper dopants and doping sites significantly influence the doping efficiency.In this work,using doping in Al N as an example,we discuss how to choose dopants and doping sites in semiconductors to create shallow defect levels.By comparing the defect properties of C_(N),O_(N),Mg_(Al),and Si_(Al)in AlN and analyzing the pros and cons of different doping approaches from the aspects of size mismatch between dopant and host elements,electronegativity difference and perturbation to the band edge states after the substitution,we propose that Mg_(Al)and Si_(Al)should be the best dopants and doping sites for p-type and n-type doping,respectively.Further first-principles calculations verify our predictions as these defects present lower formation energies and shallower defect levels.The defect charge distributions also show that the band edge states,which mainly consist of N-s and p orbitals,are less perturbed when Al is substituted,therefore,the derived defect states turn out to be delocalized,opposite to the situation when N is substituted.This approach of analyzing the band structure of the host material and choosing dopants and doping sites to minimize the perturbation on the host band structure is general and can provide reliable estimations for finding shallow defect levels in semiconductors.
基金Supported by National Natural Science Foundation of China,No.81501539the Natural Science Foundation of Guangdong Province,China,No.2016A030312008+2 种基金Science and Technology Planning Project of Shantou,China,No.200617105260368Medical Scientific Research Foundation of Guangdong,China,No.A2020627“Dengfeng Project”for the Construction of High-level Hospital in Guangdong Province-The First Affiliated Hospital of Shantou University College Supporting Funding,No.202003-10.
文摘BACKGROUND Abnormal expression patterns of mucin 2(MUC2)have been reported in a variety of malignant tumors and precancerous lesions.Reduced MUC2 expression in the intestinal mucosa,caused by various pathogenic factors,is related to mechanical dysfunction of the intestinal mucosa barrier and increased intestinal mucosal permeability.However,the relationship between MUC2 and the intestinal mucosal barrier in patients with colorectal cancer(CRC)is not clear.AIM To explore the relationship between MUC2 and intestinal mucosal barrier by characterizing the multiple expression patterns of MUC2 in CRC.METHODS Immunohistochemical staining was performed on intestinal tissue specimens from 100 CRC patients,including both cancer tissues and adjacent normal tissues.Enzyme-linked immunosorbent assays were performed on preoperative sera from 66 CRC patients and 20 normal sera to detect the serum levels of MUC2,diamine oxide(DAO),and D-lactate(D-LAC).The relationship between MUC2 expression and clinical parameters was calculated by theχ2 test or Fisher’s exact test.Prognostic value of MUC2 was evaluated by Kaplan-Meier curve and log-rank tests.RESULTS Immunohistochemical staining of 100 CRC tissues showed that the expression of MUC2 in cancer tissues was lower than that in normal tissues(54%vs 79%,P<0.05),and it was correlated with tumor-node-metastasis(TNM)stage and lymph node metastasis in CRC patients(P<0.05).However,the serum level of MUC2 in CRC patients was higher than that in normal controls,and was positively associated with serum levels of human DAO(χ2=3.957,P<0.05)and D-LAC(χ^(2)=7.236,P<0.05),which are the biomarkers of the functional status of the intestinal mucosal barrier.And the serum level of MUC2 was correlated with TNM stage,tumor type,and distant metastasis in CRC patients(P<0.05).Kaplan-Meier curves showed that decreased MUC2 expression in CRC tissues predicted a poor survival.CONCLUSION MUC2 in tissues may play a protective role by participating in the intestinal mucosal barrier and can be used as an indicator to evaluate the prognosis of CRC patients.
