New reagents for immunofluorescence analysis of carbazole series containing fluorinated β-dicarbonyl fragments and carboxylic substituent groups separated by spacers of different lengths from the light-gathering carb...New reagents for immunofluorescence analysis of carbazole series containing fluorinated β-dicarbonyl fragments and carboxylic substituent groups separated by spacers of different lengths from the light-gathering carbazole scaffold have been developed. The markers in complex with Eu<sup>3+</sup> ions possess stability in the aqueous phase, intense and prolonged luminescence (τ 550 - 570 μs) with characteristic emission maxima in the region of 615 nm and excitation wavelengths in the region of 380 - 390 nm, which distinguishes them from most of the analogs used. In the study of marker conjugation with streptavidin, a reagent containing 4 - 5 europium labeling complexes based on spacer-containing carbazole tetraketone was obtained. The marker-doped silicate nanoparticles exhibit intense and long-lived luminescence in the characteristic region.展开更多
乳腺癌(Breast cancer, BC)于2020年在全球新增癌症病例成为了最常见癌症,且发病率逐年升高。胶原蛋白是构成细胞外基质(Extracellular Matrix, ECM)的主要成分,近年来的研究发现III型胶原蛋白(Collagen Type III, COLIII)在乳腺癌的发...乳腺癌(Breast cancer, BC)于2020年在全球新增癌症病例成为了最常见癌症,且发病率逐年升高。胶原蛋白是构成细胞外基质(Extracellular Matrix, ECM)的主要成分,近年来的研究发现III型胶原蛋白(Collagen Type III, COLIII)在乳腺癌的发生、发展过程中发挥重要作用,并对肿瘤微环境(Tumor micro-environment, TME)的维持有重要意义。其中,癌症相关成纤维细胞(Cancer-associated fibroblasts, CAFs)在建立和重塑ECM结构中扮演关键角色,调控肿瘤细胞通过TME入侵的进程。但由于该体系庞大,通过分泌细胞因子和趋化因子与癌细胞相互作用的机制复杂,各成分及其亚型在癌症进展中的角色尚存争议。本文基于TME在乳腺恶性肿瘤中的研究现状以及作为ECM中重要成分的COLIII的性质结构、形态分布,分析COLIII通过改变ECM的机械力与刚度影响乳腺癌行为的机制,同时充分讨论特殊结构、来源的COLIII在微环境中的不同功能及作用方式,评估其应用于癌症治疗的可能性。展开更多
The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are ...The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are employed to measure the entire range of mixed-modeⅠ/Ⅲfracture toughness of Longmaxi shale.To theoretically interpret the fracture mechanisms,this research first introduces the detailed derivations of three established fracture criteria.By distinguishing the volumetric and distortional strain energy densities,an improved three-dimensional mean strain energy density(MSED)criterion is proposed.As the critical volumetric to distortional MSED ratio decreases,the transition from tensiondominated fracture to shear-dominated fracture is observed.Our results indicate that both peak load and applied energy increase significantly with the transition from pure mode I(i.e.,tension)to pure modeⅢ(i.e.,torsion or tearing)since mode-Ⅲcracking happens in a twisted manner and mode-Ⅰcracking occurs in a coplanar manner.The macroscopic fracture signatures are consistent with those of triaxial hydraulic fracturing.The average ratio of pure mode-Ⅲfracture toughness to pure mode-Ⅰfracture toughness is 0.68,indicating that the obtained mode-Ⅲfracture resistance for a tensionbased loading system is apparent rather than true.Compared to the three mainstream fracture criteria,the present fracture criterion exhibits greater competitiveness and can successfully evaluate and predict mixed-modeⅠ/Ⅲfracture toughness of distinct materials and loading methods.展开更多
Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynam...Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynamic responses under different temperature gradients of the slab are theoretically investigated in this work.Design/methodology/approach-Considering the moving train,the temperature gradient of the slab,and the gravity of the slab track,a dynamic model for a high-speed train that runs along the CRTS III slab track on subgrade is developed by a nonlinear coupled way in Abaqus.Findings-The results are as follows:(1)The upward transmission of the periodic deformation of the slab causes periodic track irregularity.(2)Because of the geometric constraint of limiting structures,the maximum bending stresses of the slab occur near the end of the slab under positive temperature gradients,but in the middle of the slab under negative temperature gradients.(3)The periodic deformation of the slab can induce periodic changes in the interlayer stiffness and contact status,leading to a large vibration of the slab.Because of the vibration-reduction capacity of the fastener and the larger mass of the concrete base,the accelerations of both the slab and concrete base are far less than the acceleration of the rail.Originality/value-This study reveals the influence mechanism of temperature gradient-induced periodic deformation in the dynamic responses of the train-track system,and it also provides a guide for the safe service of CRTS III slab track.展开更多
Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly fo...Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly formation of a trivalent G-quadruplex/hemin DNAzyme for colorimetric detection of Hg^(2+).A hairpin DNA(Hr)was designed with thymine-Hg^(2+)-thymine pairs that catalyzed by Exo III is prompted to happen upon binding Hg^(2+).A released DNA fragment triggers the catalytic assembly of other three hairpins(H1,H2,and H3)to form many trivalent G-quadruplex/hemin DNA enzymes for signal output.The developed sensor shows a dynamic range from 2 pM to 2μM,with an impressively low detection limit of 0.32 pM for Hg^(2+)detection.Such a sensor also has good selectivity toward Hg^(2+)detection in the presence of other common metal ions.This strategy shows the great potential for visual detection with portable type.展开更多
目的:研究分析中青年视网膜静脉阻塞(Retinal Vein Occlusion, RVO)患者同型半胱氨酸(Homocysteine, Hcy)及抗凝血酶III (Antithrombin III, AT-III)水平,两者是否作为致病危险因素参与RVO发病。分析视网膜中央静脉阻塞(CRVO)和视网膜...目的:研究分析中青年视网膜静脉阻塞(Retinal Vein Occlusion, RVO)患者同型半胱氨酸(Homocysteine, Hcy)及抗凝血酶III (Antithrombin III, AT-III)水平,两者是否作为致病危险因素参与RVO发病。分析视网膜中央静脉阻塞(CRVO)和视网膜分支静脉阻塞(BRVO)危险因素的差异,为治疗和预防该病提供客观依据。方法:1) 所有研究对象选自2021年10月至2023年12月期间就诊于内蒙古自治区人民医院眼科的年龄 P > 0.05)。三组患者之间在Hcy、AT-III、胆固醇(CHOL)、叶酸、维生素B12、D-二聚体(D-D)、纤维蛋白降解产物(FDP)水平差异均有统计学意义(P P P < 0.001)。结论:1) Hcy水平升高和AT-III活性缺乏为中青年CRVO和BRVO的危险因素。2) 相对于BRVO患者,CRVO组中Hcy水平升高和AT-III缺乏的值更为显著。展开更多
Two complexes [Eu2(2-TFMBA)6(2,2′-bipy)2]·2H2O (1) and Eu2(2-TFMBA)6(1,10-phen)2 (2) (2-TFMBA=2-(Trifluoromethyl) benzoate; 2,2′-bipy=2,2′-bipyridine; 1,10-phen= 1,10-phenanthroline) were synth...Two complexes [Eu2(2-TFMBA)6(2,2′-bipy)2]·2H2O (1) and Eu2(2-TFMBA)6(1,10-phen)2 (2) (2-TFMBA=2-(Trifluoromethyl) benzoate; 2,2′-bipy=2,2′-bipyridine; 1,10-phen= 1,10-phenanthroline) were synthesized by solvent method and determined by X-ray diffraction analysis. Complex 1 crystallizes in monoclinic system with space group P21/c, whereas complex 2 crystallizes in triclinic system with space group Pi. Both are binuclear molecules with an inversion center. In complex 1, two center Eu^3+ ions are linked together by four 2-TFMBA ligands in bidentate-bridging mode. Each Eu^3+ ion is eight-coordinated with six O atoms from five 2-TFMBA ligands and two N atoms from one 2,2′-bipy molecule. In complex 2, two center Eu^3+ ions are linked together by four 2-TFMBA ligands in two modes, namely, bidentate-bridging and tridentate-bridging. Each Eu^3+ ion is nine-coordinated with seven O atoms from five 2-TFMBA ligands and two N atoms from one 1,10-phen molecule. The two complexes both exhibited strong red fluorescence under ultraviolet light, and the ^5D0→^7Fj (j=0-4) transition emissions of Eu^3+ ion were observed in their emission spectra.展开更多
The strong photoluminescence properties of europium complexes with organic ligands attracted the attention of many researchers and found a wide range of uses in medical, industrial and biological fields. In this artic...The strong photoluminescence properties of europium complexes with organic ligands attracted the attention of many researchers and found a wide range of uses in medical, industrial and biological fields. In this article, four new Tetrakis europium complexes <b>3a</b>, <b>3b</b>, <b>3c</b> and <b>3d</b> have been prepared using 1-phenyl-4,4,4-trifluoro-1,3-butenedionato ligand and pyridinium, bipyridinium, piperazinium and piperidinium counter cations. These complexes have been characterized by negative FAB-mass. The crystal structures of <b>3a</b>, <b>3b</b>, <b>3c</b> and <b>3d</b> were determined by single crystal X-ray diffraction analysis. The complex <b>3a</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n </i><span>with four molecules in the unit cell.<i> </i>The complex <b>3b</b> crystallized in monoclinic form, space group <i>P</i>2/<i>n </i><span>with two complex molecules in the unit cell.<i> </i>The complex <b>3c</b> crystallized in monoclinic form, space group <i>C</i>2/<i>c </i><span>with sixteen molecules in the unit cell.<i> </i>The complex <b>3d</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n </i><span>with four complex molecules in the unit cell. The complex <b>3a</b> has 1,2-alternative structure, <b>3b</b> has 1,3-alternative structure, <b>3c </b>has cone like structure and <b>3d</b> has partial cone like structure. The photoluminescence properties of these complexes have been evaluated. Strong red emissions were observed in all four complexes due to <sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>2</sub> transition of Europium (III) ions under UV excitation. Four <i>β</i>-diketone ligands acted as strong antenna ligands and transferred the absorbed energy to europium (III) ion effectively;consequently strong red luminescence was observed.展开更多
The solvent extraction of uranium(VI) and europium(III) from nitric acid solution was studied with pi- colinamide dissolved in ethylene dichloride. The distribution ratios of U(VI) and Eu(III) as a function of aqueous...The solvent extraction of uranium(VI) and europium(III) from nitric acid solution was studied with pi- colinamide dissolved in ethylene dichloride. The distribution ratios of U(VI) and Eu(III) as a function of aqueous HNO3 concentration , extractant concentration in organic phase and temperature as well as the salting-out agent con- centration have been measured. The experiment results show that picolinamide has higher extractability for U(VI) than for Eu(III). The composition of extracted species, equilibrium constants and enthalpies of extraction reaction have also been presented.展开更多
The latest regulatory framework,which has been introduced globally in the form of Basel III,and its implementation in the legislation of the member states of the Euro-pean Union has generated much interest in the impa...The latest regulatory framework,which has been introduced globally in the form of Basel III,and its implementation in the legislation of the member states of the Euro-pean Union has generated much interest in the impact of regulation on the efficiency and profitability of banks.This study aims to examine the impact of the introduction of two major regulatory changes(Basel II and Basel III)on bank performance,in terms of bank size and bank-specific and macroeconomic variables.A two-stage empirical anal-ysis was conducted on a sample of 433 European commercial banks over the 2006–2015 period.In the first stage,relative efficiency was calculated using non-parametric data envelopment analysis.In the second stage,the generalized method of moments was used to examine the impact of bank-specific and macroeconomic variables as well as regulation on bank performance,that is,profitability and efficiency.Consider-ing bank size,the results show a diverse impact of regulation on bank performance.Regarding large-and medium-sized banks,regulation positively affects both efficiency and profitability,whereas,for small banks,it negatively affects performance.The results suggest that larger banks have skillfully adapted to the new regulatory environment.In contrast,small banks have problems with profitability and efficiency because the new regulatory framework has imposed additional administrative and regulatory burdens.This could result in future failure or mergers with larger banks,resulting in a higher concentration in the banking sector and increased systemic risk.Our results strongly suggest that regulation should not be implemented equally for all banks;that is,on a one size fits all terms.A distinction between small and large banks when introducing new regulatory frameworks should be made if a reasonable level of competition is to be preserved.展开更多
文摘New reagents for immunofluorescence analysis of carbazole series containing fluorinated β-dicarbonyl fragments and carboxylic substituent groups separated by spacers of different lengths from the light-gathering carbazole scaffold have been developed. The markers in complex with Eu<sup>3+</sup> ions possess stability in the aqueous phase, intense and prolonged luminescence (τ 550 - 570 μs) with characteristic emission maxima in the region of 615 nm and excitation wavelengths in the region of 380 - 390 nm, which distinguishes them from most of the analogs used. In the study of marker conjugation with streptavidin, a reagent containing 4 - 5 europium labeling complexes based on spacer-containing carbazole tetraketone was obtained. The marker-doped silicate nanoparticles exhibit intense and long-lived luminescence in the characteristic region.
基金supported by National Natural Science Foundation of China(Grant Nos.52364004,52264006,and 52164001).
文摘The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are employed to measure the entire range of mixed-modeⅠ/Ⅲfracture toughness of Longmaxi shale.To theoretically interpret the fracture mechanisms,this research first introduces the detailed derivations of three established fracture criteria.By distinguishing the volumetric and distortional strain energy densities,an improved three-dimensional mean strain energy density(MSED)criterion is proposed.As the critical volumetric to distortional MSED ratio decreases,the transition from tensiondominated fracture to shear-dominated fracture is observed.Our results indicate that both peak load and applied energy increase significantly with the transition from pure mode I(i.e.,tension)to pure modeⅢ(i.e.,torsion or tearing)since mode-Ⅲcracking happens in a twisted manner and mode-Ⅰcracking occurs in a coplanar manner.The macroscopic fracture signatures are consistent with those of triaxial hydraulic fracturing.The average ratio of pure mode-Ⅲfracture toughness to pure mode-Ⅰfracture toughness is 0.68,indicating that the obtained mode-Ⅲfracture resistance for a tensionbased loading system is apparent rather than true.Compared to the three mainstream fracture criteria,the present fracture criterion exhibits greater competitiveness and can successfully evaluate and predict mixed-modeⅠ/Ⅲfracture toughness of distinct materials and loading methods.
基金supported by National Key R&D Program of China[Grant No.2022YFB2603400]R&D Project of China State Railway Group Corporation Limited[Grant No.P2021G053]R&D Project of China Academy of Railway Science Corporation Limited[Grant No.2023YJ200].
文摘Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynamic responses under different temperature gradients of the slab are theoretically investigated in this work.Design/methodology/approach-Considering the moving train,the temperature gradient of the slab,and the gravity of the slab track,a dynamic model for a high-speed train that runs along the CRTS III slab track on subgrade is developed by a nonlinear coupled way in Abaqus.Findings-The results are as follows:(1)The upward transmission of the periodic deformation of the slab causes periodic track irregularity.(2)Because of the geometric constraint of limiting structures,the maximum bending stresses of the slab occur near the end of the slab under positive temperature gradients,but in the middle of the slab under negative temperature gradients.(3)The periodic deformation of the slab can induce periodic changes in the interlayer stiffness and contact status,leading to a large vibration of the slab.Because of the vibration-reduction capacity of the fastener and the larger mass of the concrete base,the accelerations of both the slab and concrete base are far less than the acceleration of the rail.Originality/value-This study reveals the influence mechanism of temperature gradient-induced periodic deformation in the dynamic responses of the train-track system,and it also provides a guide for the safe service of CRTS III slab track.
基金Supported by The Science and Technology Project of General Administration of Quality Supervision,Inspection and Quarantine (2015IK126)The Science and Technology Project of Changsha City of Hunan Province of China (KQ1602124).
文摘Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly formation of a trivalent G-quadruplex/hemin DNAzyme for colorimetric detection of Hg^(2+).A hairpin DNA(Hr)was designed with thymine-Hg^(2+)-thymine pairs that catalyzed by Exo III is prompted to happen upon binding Hg^(2+).A released DNA fragment triggers the catalytic assembly of other three hairpins(H1,H2,and H3)to form many trivalent G-quadruplex/hemin DNA enzymes for signal output.The developed sensor shows a dynamic range from 2 pM to 2μM,with an impressively low detection limit of 0.32 pM for Hg^(2+)detection.Such a sensor also has good selectivity toward Hg^(2+)detection in the presence of other common metal ions.This strategy shows the great potential for visual detection with portable type.
文摘目的:研究分析中青年视网膜静脉阻塞(Retinal Vein Occlusion, RVO)患者同型半胱氨酸(Homocysteine, Hcy)及抗凝血酶III (Antithrombin III, AT-III)水平,两者是否作为致病危险因素参与RVO发病。分析视网膜中央静脉阻塞(CRVO)和视网膜分支静脉阻塞(BRVO)危险因素的差异,为治疗和预防该病提供客观依据。方法:1) 所有研究对象选自2021年10月至2023年12月期间就诊于内蒙古自治区人民医院眼科的年龄 P > 0.05)。三组患者之间在Hcy、AT-III、胆固醇(CHOL)、叶酸、维生素B12、D-二聚体(D-D)、纤维蛋白降解产物(FDP)水平差异均有统计学意义(P P P < 0.001)。结论:1) Hcy水平升高和AT-III活性缺乏为中青年CRVO和BRVO的危险因素。2) 相对于BRVO患者,CRVO组中Hcy水平升高和AT-III缺乏的值更为显著。
基金supported by the Natural Science Foundation of Beijing (2073022)
文摘Two complexes [Eu2(2-TFMBA)6(2,2′-bipy)2]·2H2O (1) and Eu2(2-TFMBA)6(1,10-phen)2 (2) (2-TFMBA=2-(Trifluoromethyl) benzoate; 2,2′-bipy=2,2′-bipyridine; 1,10-phen= 1,10-phenanthroline) were synthesized by solvent method and determined by X-ray diffraction analysis. Complex 1 crystallizes in monoclinic system with space group P21/c, whereas complex 2 crystallizes in triclinic system with space group Pi. Both are binuclear molecules with an inversion center. In complex 1, two center Eu^3+ ions are linked together by four 2-TFMBA ligands in bidentate-bridging mode. Each Eu^3+ ion is eight-coordinated with six O atoms from five 2-TFMBA ligands and two N atoms from one 2,2′-bipy molecule. In complex 2, two center Eu^3+ ions are linked together by four 2-TFMBA ligands in two modes, namely, bidentate-bridging and tridentate-bridging. Each Eu^3+ ion is nine-coordinated with seven O atoms from five 2-TFMBA ligands and two N atoms from one 1,10-phen molecule. The two complexes both exhibited strong red fluorescence under ultraviolet light, and the ^5D0→^7Fj (j=0-4) transition emissions of Eu^3+ ion were observed in their emission spectra.
文摘The strong photoluminescence properties of europium complexes with organic ligands attracted the attention of many researchers and found a wide range of uses in medical, industrial and biological fields. In this article, four new Tetrakis europium complexes <b>3a</b>, <b>3b</b>, <b>3c</b> and <b>3d</b> have been prepared using 1-phenyl-4,4,4-trifluoro-1,3-butenedionato ligand and pyridinium, bipyridinium, piperazinium and piperidinium counter cations. These complexes have been characterized by negative FAB-mass. The crystal structures of <b>3a</b>, <b>3b</b>, <b>3c</b> and <b>3d</b> were determined by single crystal X-ray diffraction analysis. The complex <b>3a</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n </i><span>with four molecules in the unit cell.<i> </i>The complex <b>3b</b> crystallized in monoclinic form, space group <i>P</i>2/<i>n </i><span>with two complex molecules in the unit cell.<i> </i>The complex <b>3c</b> crystallized in monoclinic form, space group <i>C</i>2/<i>c </i><span>with sixteen molecules in the unit cell.<i> </i>The complex <b>3d</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n </i><span>with four complex molecules in the unit cell. The complex <b>3a</b> has 1,2-alternative structure, <b>3b</b> has 1,3-alternative structure, <b>3c </b>has cone like structure and <b>3d</b> has partial cone like structure. The photoluminescence properties of these complexes have been evaluated. Strong red emissions were observed in all four complexes due to <sup>5</sup>D<sub>0</sub> → <sup>7</sup>F<sub>2</sub> transition of Europium (III) ions under UV excitation. Four <i>β</i>-diketone ligands acted as strong antenna ligands and transferred the absorbed energy to europium (III) ion effectively;consequently strong red luminescence was observed.
文摘The solvent extraction of uranium(VI) and europium(III) from nitric acid solution was studied with pi- colinamide dissolved in ethylene dichloride. The distribution ratios of U(VI) and Eu(III) as a function of aqueous HNO3 concentration , extractant concentration in organic phase and temperature as well as the salting-out agent con- centration have been measured. The experiment results show that picolinamide has higher extractability for U(VI) than for Eu(III). The composition of extracted species, equilibrium constants and enthalpies of extraction reaction have also been presented.
基金supported by the University of Rijeka projects uniri-mladi-drustv-20-5.and uniri-drustv-18-228.
文摘The latest regulatory framework,which has been introduced globally in the form of Basel III,and its implementation in the legislation of the member states of the Euro-pean Union has generated much interest in the impact of regulation on the efficiency and profitability of banks.This study aims to examine the impact of the introduction of two major regulatory changes(Basel II and Basel III)on bank performance,in terms of bank size and bank-specific and macroeconomic variables.A two-stage empirical anal-ysis was conducted on a sample of 433 European commercial banks over the 2006–2015 period.In the first stage,relative efficiency was calculated using non-parametric data envelopment analysis.In the second stage,the generalized method of moments was used to examine the impact of bank-specific and macroeconomic variables as well as regulation on bank performance,that is,profitability and efficiency.Consider-ing bank size,the results show a diverse impact of regulation on bank performance.Regarding large-and medium-sized banks,regulation positively affects both efficiency and profitability,whereas,for small banks,it negatively affects performance.The results suggest that larger banks have skillfully adapted to the new regulatory environment.In contrast,small banks have problems with profitability and efficiency because the new regulatory framework has imposed additional administrative and regulatory burdens.This could result in future failure or mergers with larger banks,resulting in a higher concentration in the banking sector and increased systemic risk.Our results strongly suggest that regulation should not be implemented equally for all banks;that is,on a one size fits all terms.A distinction between small and large banks when introducing new regulatory frameworks should be made if a reasonable level of competition is to be preserved.