Background Chronic heart failure (CHF) is associated with calcium transients and calcium handling proteins. Angiotensin converting enzyme (ACE) inhibitor has been demonstrated to have beneficial effect on CHF. Yet st...Background Chronic heart failure (CHF) is associated with calcium transients and calcium handling proteins. Angiotensin converting enzyme (ACE) inhibitor has been demonstrated to have beneficial effect on CHF. Yet studies addressed to the relationship between ACE inhibitor and calcium transients in CHF are rare. The aim of this study was to investigate the influence of ACE inhibitor (perindopril) on the contractility and calcium transients and calcium handling proteins in ventricular myocytes from rats with experimental heart failure.Methods Male Wistar rats were randomized to heart failure group treated with perindopril (CHF-T, 3 mg·kg -1 ·d -1 ), heart failure group without treatment (CHF-C) and sham-operated group (PS). Heart failure was induced by abdominal aortic constriction. All groups were further followed up for 12 weeks. Left ventricular myocytes were then isolated. Single cell shortening fraction and [Ca 2+ ]_i were simultaneously measured by laser scanning confocal microscope under the field stimulation (1.0 Hz). Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot were performed to evaluate the changes of mRNA and protein of Na +-Ca 2+ exchanger (NCX_1), sarcoplasmic reticulum Ca 2+ -ATPase (SERCA_2) and phospholamban (PLB).Results The fraction of cell shortening (FS%) and [Ca 2+ ]_ imax (nmol/L) were significantly reduced in group CHF-C compared with group PS (FS%: 7.51±1.15 vs 13.21±1.49;[Ca 2+ ]_ imax :330.85±50.05 vs 498.16±14.07; both P <0.01), and restored at least partially in CHF-T group. In CHF-C group, the left ventricular mRNA of NCX_1 and PLB were significantly upregulated in comparing with PS group (R_ NCX1/β-Actin : 0.51±0.12 vs 0.19±0.06, P <0.01; R_ PLB/β-Actin : 0.26±0.12 vs 0.20±0.08, P <0.05), while SERCA_2 mRNA was downregulated (0.48±0.10 vs 0.80±0.11, P <0.01). The mRNA levels of NCX_1 and SERCA_2 in CHF-T group were between the CHF-C and PS group, and the differences of the latter two groups were significant (all P <0.05). In CHF-C and CHF-T groups, the protein expression of NCX_1 were 1.141±0.047 and 1.074±0.081 times of that in PS group respectively (both P <0.05), and SERCA_2 protein levels were 0.803±0.100 and 0.893±0.084 times of that in PS group respectively (both P <0.05). The protein expression of NCX_1 and SERCA_2 in the CHF-C and CHF-T groups is significantly different (both P <0.05).ConclusionACE inhibitor could improve cardiac function of failing heart through directly enhancing the contractility of single cardiomyocyte, and these effects are probably mediated by its roles in preventing the deleterious changes of calcium transients and calcium handling proteins in CHF.展开更多
Hydrogen peroxide(H_(2)O_(2))photoproduction in seawater with metal-free photocatalysts derived from biomass materials is a green,sustainable,and ultra environmentally friendly way.However,most photocatalysts are alwa...Hydrogen peroxide(H_(2)O_(2))photoproduction in seawater with metal-free photocatalysts derived from biomass materials is a green,sustainable,and ultra environmentally friendly way.However,most photocatalysts are always corroded or poisoned in seawater,resulting in a significantly reduced catalytic performance.Here,we report the metal-free photocatalysts(RUT-1 to RUT-5)with in-situ generated carbon dots(CDs)from biomass materials(Rutin)by a simple microwave-assisted pyrolysis method.Under visible light(λ≥420 nm,81.6 mW/cm^(2)),the optimized catalyst of RUT-4 is stable and can achieve a high H_(2)O_(2)yield of 330.36μmol/L in seawater,1.78 times higher than that in normal water.New transient potential scanning(TPS)tests are developed and operated to in-situ study the H_(2)O_(2)photoproduction of RUT-4 under operation condition.RUT-4 has strong oxygen(O_(2))absorption capacity,and the O_(2)reduction rate in seawater is higher than that in water.Metal cations in seawater further promote the photo-charge separation and facilitate the photo-reduction reaction.For RUT-4,the conduction band level under operating conditions only satisfies the requirement of O_(2)reduction but not for hydrogen(H2)evolution.This work provides new insights for the in-situ study of photocatalyst under operation condition,and gives a green and sustainable path for the H_(2)O_(2)photoproduction with metal-free catalysts in seawater.展开更多
Oxygen evolution reaction(OER)plays a crucial role in developing energy conversion and adjusting electronic structure of the electrocatalysts can effectively improve the catalytic activity and stability.However,it is ...Oxygen evolution reaction(OER)plays a crucial role in developing energy conversion and adjusting electronic structure of the electrocatalysts can effectively improve the catalytic activity and stability.However,it is a challenge to adjust the electronic structure on two-dimensional iridium dioxide nanosheets(IrO_(2)NS),which have the advantages of high atom utilization.Here,we regulate the surface properties of IrO_(2)NS through sulfonated carbon dots(SCDs)to promote the OER catalytic process.The catalyst IrO_(2)NS/SCDs-2 exhibited excellent catalytic activity with a lower overpotential of 180 mV than IrO_(2)NS(230 mV)at the current density of 10 mA·cm^(-2)in a 0.5 M H_(2)SO_(4) solution.And after 160 h of stability testing,the overpotential of IrO_(2)NS/SCDs-2 only decreased by 4 mV.Moreover,transient potential scanning test can visually demonstrate that the addition of SCDs improves the conductivity of the catalyst and increases the electron transfer rate.展开更多
文摘Background Chronic heart failure (CHF) is associated with calcium transients and calcium handling proteins. Angiotensin converting enzyme (ACE) inhibitor has been demonstrated to have beneficial effect on CHF. Yet studies addressed to the relationship between ACE inhibitor and calcium transients in CHF are rare. The aim of this study was to investigate the influence of ACE inhibitor (perindopril) on the contractility and calcium transients and calcium handling proteins in ventricular myocytes from rats with experimental heart failure.Methods Male Wistar rats were randomized to heart failure group treated with perindopril (CHF-T, 3 mg·kg -1 ·d -1 ), heart failure group without treatment (CHF-C) and sham-operated group (PS). Heart failure was induced by abdominal aortic constriction. All groups were further followed up for 12 weeks. Left ventricular myocytes were then isolated. Single cell shortening fraction and [Ca 2+ ]_i were simultaneously measured by laser scanning confocal microscope under the field stimulation (1.0 Hz). Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot were performed to evaluate the changes of mRNA and protein of Na +-Ca 2+ exchanger (NCX_1), sarcoplasmic reticulum Ca 2+ -ATPase (SERCA_2) and phospholamban (PLB).Results The fraction of cell shortening (FS%) and [Ca 2+ ]_ imax (nmol/L) were significantly reduced in group CHF-C compared with group PS (FS%: 7.51±1.15 vs 13.21±1.49;[Ca 2+ ]_ imax :330.85±50.05 vs 498.16±14.07; both P <0.01), and restored at least partially in CHF-T group. In CHF-C group, the left ventricular mRNA of NCX_1 and PLB were significantly upregulated in comparing with PS group (R_ NCX1/β-Actin : 0.51±0.12 vs 0.19±0.06, P <0.01; R_ PLB/β-Actin : 0.26±0.12 vs 0.20±0.08, P <0.05), while SERCA_2 mRNA was downregulated (0.48±0.10 vs 0.80±0.11, P <0.01). The mRNA levels of NCX_1 and SERCA_2 in CHF-T group were between the CHF-C and PS group, and the differences of the latter two groups were significant (all P <0.05). In CHF-C and CHF-T groups, the protein expression of NCX_1 were 1.141±0.047 and 1.074±0.081 times of that in PS group respectively (both P <0.05), and SERCA_2 protein levels were 0.803±0.100 and 0.893±0.084 times of that in PS group respectively (both P <0.05). The protein expression of NCX_1 and SERCA_2 in the CHF-C and CHF-T groups is significantly different (both P <0.05).ConclusionACE inhibitor could improve cardiac function of failing heart through directly enhancing the contractility of single cardiomyocyte, and these effects are probably mediated by its roles in preventing the deleterious changes of calcium transients and calcium handling proteins in CHF.
基金supported by Natural Science Foundation of Jiangsu Province(No.BK20220028)the National Key Research and Development Program of China(Nos.2020YFA0406104 and 2020YFA0406101)+6 种基金the National Natural Science Foundation of China(Nos.52272043,52271223,52202107,and 52201269)Natural Science Foundation of Jiangsu Province(Nos.BK20210735 and 21KJB430043)the Science and Technology Development Fund,Macao SAR(No.0009/2022/ITP)Shenzhen Science and Technology Plan Project(Collaborative Innovation Special Project,SGDX20220530111203019)Collaborative Innovation Center of Suzhou Nano Science and Technologythe 111 ProjectSuzhou Key Laboratory of Functional Nano and Soft Materials.
文摘Hydrogen peroxide(H_(2)O_(2))photoproduction in seawater with metal-free photocatalysts derived from biomass materials is a green,sustainable,and ultra environmentally friendly way.However,most photocatalysts are always corroded or poisoned in seawater,resulting in a significantly reduced catalytic performance.Here,we report the metal-free photocatalysts(RUT-1 to RUT-5)with in-situ generated carbon dots(CDs)from biomass materials(Rutin)by a simple microwave-assisted pyrolysis method.Under visible light(λ≥420 nm,81.6 mW/cm^(2)),the optimized catalyst of RUT-4 is stable and can achieve a high H_(2)O_(2)yield of 330.36μmol/L in seawater,1.78 times higher than that in normal water.New transient potential scanning(TPS)tests are developed and operated to in-situ study the H_(2)O_(2)photoproduction of RUT-4 under operation condition.RUT-4 has strong oxygen(O_(2))absorption capacity,and the O_(2)reduction rate in seawater is higher than that in water.Metal cations in seawater further promote the photo-charge separation and facilitate the photo-reduction reaction.For RUT-4,the conduction band level under operating conditions only satisfies the requirement of O_(2)reduction but not for hydrogen(H2)evolution.This work provides new insights for the in-situ study of photocatalyst under operation condition,and gives a green and sustainable path for the H_(2)O_(2)photoproduction with metal-free catalysts in seawater.
基金supported by Natural Science Foundation of Jiangsu Province(No.BK20220028)the National Key R&D Program of China(Nos.2020YFA0406104 and 2020YFA0406101)+2 种基金the National Natural Science Foundation of China(Nos.52271223,52272043,52202107,52201269,22273063 and 52302296)the Science and Technology Development Fund,Macao SAR(No.0009/2022/ITP)Collaborative Innovation Center of Suzhou Nano Science and Technology,the 111 Project and Suzhou Key Laboratory of Functional Nano and Soft Materials.
文摘Oxygen evolution reaction(OER)plays a crucial role in developing energy conversion and adjusting electronic structure of the electrocatalysts can effectively improve the catalytic activity and stability.However,it is a challenge to adjust the electronic structure on two-dimensional iridium dioxide nanosheets(IrO_(2)NS),which have the advantages of high atom utilization.Here,we regulate the surface properties of IrO_(2)NS through sulfonated carbon dots(SCDs)to promote the OER catalytic process.The catalyst IrO_(2)NS/SCDs-2 exhibited excellent catalytic activity with a lower overpotential of 180 mV than IrO_(2)NS(230 mV)at the current density of 10 mA·cm^(-2)in a 0.5 M H_(2)SO_(4) solution.And after 160 h of stability testing,the overpotential of IrO_(2)NS/SCDs-2 only decreased by 4 mV.Moreover,transient potential scanning test can visually demonstrate that the addition of SCDs improves the conductivity of the catalyst and increases the electron transfer rate.
