AIM To investigate the role of peritoneal macrophage(PM) polarization in the therapeutic effect of abdominal paracentesis drainage(APD) on severe acute pancreatitis(SAP).METHODS SAP was induced by 5% Na-taurocholate r...AIM To investigate the role of peritoneal macrophage(PM) polarization in the therapeutic effect of abdominal paracentesis drainage(APD) on severe acute pancreatitis(SAP).METHODS SAP was induced by 5% Na-taurocholate retrograde injection in Sprague-Dawley rats. APD was performed by inserting a drainage tube with a vacuum ball into the lower right abdomen of the rats immediately after the induction of SAP. To verify the effect of APD on macrophages, PMs were isolated and cultured in an environment, with the peritoneal inflammatory environment simulated by the addition of peritoneal lavage in complete RPMI 1640 medium. Hematoxylin and eosin staining was performed. The levels of pancreatitis biomarkers amylase and lipase as well as the levels of inflammatory mediators in the blood and peritoneal lavage were determined. The polarization phenotypes of the PMs were identified by detecting the marker expression of M1/M2 macrophages via flow cytometry, qPCR and immunohistochemical staining. The protein expression in macrophages that had infiltrated the pancreas was determined by Western blot.RESULTS APD treatment significantly reduced the histopathological scores and levels of amylase, lipase, tumor necrosis factor-α and interleukin(IL)-1β, indicating that APD ameliorates the severity of SAP. Importantly, we found that APD treatment polarized PMs towards the M2 phenotype, as evidenced by the reduced number of M1 macrophages and the reduced levels of proinflammatory mediators, such as IL-1β and L-selectin, as well as the increased number of M2 macrophages and increased levels of anti-inflammatory mediators, such as IL-4 and IL-10. Furthermore, in an in vitro study wherein peritoneal lavage from the APD group was added to the cultured PMs to simulate the peritoneal inflammatory environment, PMs also exhibited a dominant M2 phenotype, resulting in a significantly lower level of inflammation. Finally, APD treatment increased the proportion of M2 macrophages and upregulated the expression of the anti-inflammatory protein Arg-1 in the pancreas of SAP model rats.CONCLUSION These findings suggest that APD treatment exerts antiinflammatory effects by regulating the M2 polarization of PMs, providing novel insights into the mechanism underlying its therapeutic effect.展开更多
AIM: To observe the anti-liver fibrosis effect of Astragalus complanatus fiavonoids (ACF) in rats. METHODS: The liver fibrosis model in rats was established by injecting interperitoneally 0.2 mL/100 g 0.5% dimethy...AIM: To observe the anti-liver fibrosis effect of Astragalus complanatus fiavonoids (ACF) in rats. METHODS: The liver fibrosis model in rats was established by injecting interperitoneally 0.2 mL/100 g 0.5% dimethylnitrosamine, thrice a week. Meanwhile, the rats were administered ACF (30, 60, 120 mg/kg) or colchicine (0.1 mg/kg) once a day for 1 mo. Serum N-propeptide of type Ⅰ procollagen (PINP) and type Ⅲ procollagen (PⅢNP) was measured using ELISA. Malondialdehyde (MDA) and superoxide dismutase (SOD) in hepatic tissue were evaluated. Matrix metal protease-1 (MMP-1) mRNA expression was assayed by RT-PCR and the protein expression of tissue inhibitor of metal protease-1 (TIMP-1) was analyzed by immunohistochemistry. RESULTS: In the ACF groups, SOD activity increased and MDA content decreased in comparison to the liver fibrosis model group. The serum PINP and PⅢNP contents in ACF-2 and -3 group decreased compared to those in model group. In ACF-2 and -3 group, the expression of MMP-1 mRNA increased significantly and the protein expression of TIMP-1 decreased compared to that in model group. CONCLUSION: The antifibrotic mechanisms of ACF are associated with its influence on lipid peroxidation and collagen synthesis and degradation.展开更多
·AIM:To assess the reproducibility of macular perfusion parameters in non-proliferative diabetic retinopathy(NPDR)patients measured by different examiners and two different sweep modes of optical coherence tomogr...·AIM:To assess the reproducibility of macular perfusion parameters in non-proliferative diabetic retinopathy(NPDR)patients measured by different examiners and two different sweep modes of optical coherence tomography angiography(OCTA).·METHODS:Ninety-eight(98 eyes)patients with NPDR were included in this study.All participates were performed three times using Cirrus OCTA with Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode by two examiners.The macular foveal avascular zone(FAZ)and vessel density(VD)in the superficial retinal layer(SRL)were measured.The reproducibility of the measurements was evaluated with intraclass correlation coefficients(ICC)and coefficient of variation(CoV).·RESULTS:The intra-mode ICCs of Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode were 0.957 to 0.959 and 0.964 to 0.977,respectively;and the inter-mode ICCs were 0.962 to 0.970.The intra-examiner ICCs of macular perfusion parameters were>0.950;and the inter-examiner ICCs were0.928 to 0.969.All CoVs were<1.0%.·CONCLUSION:Cirrus OCTA can measure macular perfusion parameters in NPDR patients with excellent reproducibility.The measurements of FAZ and VD in the SRL determined by Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode are highly consistent and both sweep modes are suitable for macular perfusion parameters measurement.展开更多
Eleven env mutants were designed and generated by site-directed mutagenesis of the regions around NAb epitopes and deletions of variable regions in env. The immunogenicities of the generated mutants were evaluated usi...Eleven env mutants were designed and generated by site-directed mutagenesis of the regions around NAb epitopes and deletions of variable regions in env. The immunogenicities of the generated mutants were evaluated using single-cycle infection neutralization assays with two pseudoviruses and IFN-γ ELISPOT. Overall, five mutants (dWt, M2, M5-2, M5-1 and dM7) induced higher neutralization activities for both pseudoviruses than plasmid Wt, while only two of the mutants (dWt and M5-2) showed significant differences (P<0.05). Two mutants (M2 and dM2) induced more Env-specific T cells than plasmid Wt. Statistically however, significance was only reached for mutant M2. Thus, properly modified HIV-1 Env may have the potential to induce potent cellular and humoral immune responses.展开更多
Objective:To investigate the phenotypic characteristics and functional capability differences of mouse bone marrow-derived dendritic cells after stimulation with Mycobacterium tuberculosis in the presence or absence o...Objective:To investigate the phenotypic characteristics and functional capability differences of mouse bone marrow-derived dendritic cells after stimulation with Mycobacterium tuberculosis in the presence or absence of vitamin 03.Methods:Mouse bone marrow-derived cells were cultured with GM-CSF(20 ng/mL).Then,one was added with 100 nmol/L of 25(OH)D3,while the other did not.On day 6.5 μg/mL of BCG was added to stimulate the cells for 24 h.On day 7,suspension cells were harvested for phenotypic and functional analyses.Results:The percentages of CD86 dendritic cells(DCs) in the control group and 25(OH)D3 group were 66.97%± 8.29%and 52.18%± 8.52%.respectively;the mean fluorescence intensities of MHC- Ⅱ in the control group and 25(OH)D3 group were 1 102.16 ± 371.02 and 681.62± 292.71.The expression levels of MHC- Ⅱ and CD86 on the surface of the DCs in 25(OH)D3 group were significantly lower than those of the control group.The ability of the DCs to stimulate proliferation of T-lymphocytes was also significantly lower than that of the control group.Conclusions:These findings suggest that 25(OH)D3 modulates the immune response by affecting the maturation and function of DCs in Mycobacterium tuberculosis period.展开更多
The ELISPOT assay is increasingly used for assessing cellular immune responses in clinical trials of HIV-1 or cancer vaccines. However, to date, data from clinical trials do not consistently show that immune responses...The ELISPOT assay is increasingly used for assessing cellular immune responses in clinical trials of HIV-1 or cancer vaccines. However, to date, data from clinical trials do not consistently show that immune responses are correlated with clinical endpoints. This is due in part to the lack of assay standardization and validation across laboratories and therefore, a quality control panel is required to establish competency and comparability amongst different laboratories. In this study peripheral blood mononuclear cells (PBMCs) from healthy individuals were screened and frozen in liquid nitrogen. The recovery and viability of the PBMCs and the frequencies of interferon (IFN)-γ-secreting cells after CEF peptide pool stimulation were detected after various intervals in seven different laboratories. The recovery and viability did not differ significantly after different intervals. Although the frequencies of IFN (interferon)-γ-secreting cells among thawed PBMCs (peripheral blood mononuclear cells) fluctuated after CEF peptide pool stimulation at different intervals, they were not significantly decreased compared with those among fresh PBMCs. However, the viabilities, recoveries and frequencies of IFN-γ-secreting cells differed significantly among the seven laboratories. Our results indicate that cryopreserved PBMCs could be used as a quality control panel for ELISPOT. However, the procedures for ELISPOT need to be standardized amongst different laboratories.展开更多
To evaluate the maneuverability and efficacy of phacoemulsification and intraocular lens(IOL) implantation in eyes with corneal opacities after deep anterior lamellar keratoplasty(DALK), twelve eyes of 12 patients wit...To evaluate the maneuverability and efficacy of phacoemulsification and intraocular lens(IOL) implantation in eyes with corneal opacities after deep anterior lamellar keratoplasty(DALK), twelve eyes of 12 patients with mild to moderate corneal opacities after DALK and coexisting cataracts were analyzed retrospectively. Phacoemulsification and IOL implantation assisted with anterior capsule staining, as well as non-invasive optical fiber illumination, were performed on all eyes. No intraoperative or postoperative complications were noted. Mean corrected distance visual acuity(logMAR) improved from 1.24±0.17 to 0.73±0.22. Post-phaco intraocular pressure was maintained between 13 to 20 mm Hg in all cases throughout the follow-up period. Mean endothelial cell density decreased from 2258.42±205.94 to 1906.25±174.23 cells/mm2. Phacoemulsification and IOL implantation are safe and valid in eyes with mild to moderate corneal opacities after DALK and coexisting cataracts when assisted with anterior capsule staining and non-invasive optical fiber illumination.展开更多
Two new quinazoline derivatives versicomides E(1)and F(2),and 10 known compounds(3-12)were isolated from the moss endophytic fungus Aspergillus sp.Their structures were determined on the basis of extensive spectroscop...Two new quinazoline derivatives versicomides E(1)and F(2),and 10 known compounds(3-12)were isolated from the moss endophytic fungus Aspergillus sp.Their structures were determined on the basis of extensive spectroscopic data analysis and ECD calculations.Among them,the compound 7(6-hydroxy-3-methoxyviridicatin)was first reported as a natural product.Inhibition on LPS-induced NO production in RAW 264.7 murine macrophages found that compounds 5,7 and 8 showed significant inhibitory effects on NO production,with IC50 values of 49.85,22.14 and 46.02μM respectively.展开更多
Sensitivity to structure and composition is very challenging to establish in nanocatalysis due to inadequate definition of structures that are very close in composition.We synthesized a pair of atomically precise copp...Sensitivity to structure and composition is very challenging to establish in nanocatalysis due to inadequate definition of structures that are very close in composition.We synthesized a pair of atomically precise copper clusters that are very close in composition,[Cu_(20)H_(9)(Tf-dpf)_(10)]·BF4(Cu_(20)H_(9))and[Cu_(20)H_(8)(Tf-dpf)_(10)]·(BF_(4))_(2)(Cu_(20)H_(8)),by using a pyridyl-functionalized flexible amidinate ligand,N,N′-di(5-trifluoromethyl-2-pyridyl)formamidinate.The one-hydride difference in their composition leads to significant variation in geometric and electronic structures and,consequently,distinctly different optical and catalytic properties.Cu_(20)H_(8)exhibits 25 times higher catalytic activity than Cu_(20)H_(9)(96.7%vs 3.7%in yield)in the selective hydrogenation of anα,β-unsaturated aldehyde(cinnamaldehyde)to saturated aldehyde(3-phenylpropanal).Electrospray ionization mass spectrometry combined with density functional theory calculations reveal that the greater ease of dissociation of one Tf-dpf ligand compared to Cu_(20)H_(8)is the key to its higher activity.This work demonstrates a clear case of structure and composition sensitivity in nanocatalysis and that one hydride,out of∼330 atoms in the nanoclusters,can make a huge difference in the catalytic activity.These insights will be useful in the design and synthesis of atomically precise nanocatalysts.展开更多
Myocardial ischemia/reperfusion(/R)injury is a classic type of cardiovascular disease characterized by injury to cardiomyocytes leading to various forms of cell death.It is believed that irreversible myocardial damage...Myocardial ischemia/reperfusion(/R)injury is a classic type of cardiovascular disease characterized by injury to cardiomyocytes leading to various forms of cell death.It is believed that irreversible myocardial damage resulted from I/R occurs due to oxidative stress evoked during the reperfusion phase.Here we demonstrate that ischemia triggers a specific redox reaction of polyunsaturated fatty acids(PUFA)-phospholipids in myocardial cells,which acts as a priming signaling that initiates the outbreak of robust oxidative damage in the reperfusion phase.Using animal and in vitro models,the crucial lipid species in I/R injury were identifed to be oxidized PUFAs enriched phosphatidylethanolamines.Using multi-omics,arachidonic acid 15-lipoxygenase-1(ALOx15)was identified as the primary mediator of ischemia-provoked phospholipid peroxidation,which was further confirmed using chemogenetic approaches.Collectively,our results reveal that ALOx15 induction in the ischemia phase acts as a"burning point"to ignite phospholipid oxidization into ferroptotic signals.This finding characterizes a novel molecular mechanism for myocardial ischemia injury and offers a potential therapeutic target for early intervention of V/R injury.展开更多
基金the National Natural Science Foundation of China,No.81772001,No.8177071311 and No.81502696the National Clinical Key Subject of China,No.41792113+1 种基金the Technology Plan Program of Sichuan Province,No.2015SZ0229,No.2018JY0041 and No.18YYJC0442the Science and Technology Development Plan of Sichuan Province,No.2016YJ0023
文摘AIM To investigate the role of peritoneal macrophage(PM) polarization in the therapeutic effect of abdominal paracentesis drainage(APD) on severe acute pancreatitis(SAP).METHODS SAP was induced by 5% Na-taurocholate retrograde injection in Sprague-Dawley rats. APD was performed by inserting a drainage tube with a vacuum ball into the lower right abdomen of the rats immediately after the induction of SAP. To verify the effect of APD on macrophages, PMs were isolated and cultured in an environment, with the peritoneal inflammatory environment simulated by the addition of peritoneal lavage in complete RPMI 1640 medium. Hematoxylin and eosin staining was performed. The levels of pancreatitis biomarkers amylase and lipase as well as the levels of inflammatory mediators in the blood and peritoneal lavage were determined. The polarization phenotypes of the PMs were identified by detecting the marker expression of M1/M2 macrophages via flow cytometry, qPCR and immunohistochemical staining. The protein expression in macrophages that had infiltrated the pancreas was determined by Western blot.RESULTS APD treatment significantly reduced the histopathological scores and levels of amylase, lipase, tumor necrosis factor-α and interleukin(IL)-1β, indicating that APD ameliorates the severity of SAP. Importantly, we found that APD treatment polarized PMs towards the M2 phenotype, as evidenced by the reduced number of M1 macrophages and the reduced levels of proinflammatory mediators, such as IL-1β and L-selectin, as well as the increased number of M2 macrophages and increased levels of anti-inflammatory mediators, such as IL-4 and IL-10. Furthermore, in an in vitro study wherein peritoneal lavage from the APD group was added to the cultured PMs to simulate the peritoneal inflammatory environment, PMs also exhibited a dominant M2 phenotype, resulting in a significantly lower level of inflammation. Finally, APD treatment increased the proportion of M2 macrophages and upregulated the expression of the anti-inflammatory protein Arg-1 in the pancreas of SAP model rats.CONCLUSION These findings suggest that APD treatment exerts antiinflammatory effects by regulating the M2 polarization of PMs, providing novel insights into the mechanism underlying its therapeutic effect.
文摘AIM: To observe the anti-liver fibrosis effect of Astragalus complanatus fiavonoids (ACF) in rats. METHODS: The liver fibrosis model in rats was established by injecting interperitoneally 0.2 mL/100 g 0.5% dimethylnitrosamine, thrice a week. Meanwhile, the rats were administered ACF (30, 60, 120 mg/kg) or colchicine (0.1 mg/kg) once a day for 1 mo. Serum N-propeptide of type Ⅰ procollagen (PINP) and type Ⅲ procollagen (PⅢNP) was measured using ELISA. Malondialdehyde (MDA) and superoxide dismutase (SOD) in hepatic tissue were evaluated. Matrix metal protease-1 (MMP-1) mRNA expression was assayed by RT-PCR and the protein expression of tissue inhibitor of metal protease-1 (TIMP-1) was analyzed by immunohistochemistry. RESULTS: In the ACF groups, SOD activity increased and MDA content decreased in comparison to the liver fibrosis model group. The serum PINP and PⅢNP contents in ACF-2 and -3 group decreased compared to those in model group. In ACF-2 and -3 group, the expression of MMP-1 mRNA increased significantly and the protein expression of TIMP-1 decreased compared to that in model group. CONCLUSION: The antifibrotic mechanisms of ACF are associated with its influence on lipid peroxidation and collagen synthesis and degradation.
基金Supported by National Natural Science Foundation of China(No.82070920)Major Clinical Research Projects of the Three-Year Action Plan for Promoting Clinicial Skills and Clinical Innovation in Municipal Hospitals(No.SHDC2020CR1043B-010)。
文摘·AIM:To assess the reproducibility of macular perfusion parameters in non-proliferative diabetic retinopathy(NPDR)patients measured by different examiners and two different sweep modes of optical coherence tomography angiography(OCTA).·METHODS:Ninety-eight(98 eyes)patients with NPDR were included in this study.All participates were performed three times using Cirrus OCTA with Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode by two examiners.The macular foveal avascular zone(FAZ)and vessel density(VD)in the superficial retinal layer(SRL)were measured.The reproducibility of the measurements was evaluated with intraclass correlation coefficients(ICC)and coefficient of variation(CoV).·RESULTS:The intra-mode ICCs of Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode were 0.957 to 0.959 and 0.964 to 0.977,respectively;and the inter-mode ICCs were 0.962 to 0.970.The intra-examiner ICCs of macular perfusion parameters were>0.950;and the inter-examiner ICCs were0.928 to 0.969.All CoVs were<1.0%.·CONCLUSION:Cirrus OCTA can measure macular perfusion parameters in NPDR patients with excellent reproducibility.The measurements of FAZ and VD in the SRL determined by Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode are highly consistent and both sweep modes are suitable for macular perfusion parameters measurement.
文摘Eleven env mutants were designed and generated by site-directed mutagenesis of the regions around NAb epitopes and deletions of variable regions in env. The immunogenicities of the generated mutants were evaluated using single-cycle infection neutralization assays with two pseudoviruses and IFN-γ ELISPOT. Overall, five mutants (dWt, M2, M5-2, M5-1 and dM7) induced higher neutralization activities for both pseudoviruses than plasmid Wt, while only two of the mutants (dWt and M5-2) showed significant differences (P<0.05). Two mutants (M2 and dM2) induced more Env-specific T cells than plasmid Wt. Statistically however, significance was only reached for mutant M2. Thus, properly modified HIV-1 Env may have the potential to induce potent cellular and humoral immune responses.
文摘Objective:To investigate the phenotypic characteristics and functional capability differences of mouse bone marrow-derived dendritic cells after stimulation with Mycobacterium tuberculosis in the presence or absence of vitamin 03.Methods:Mouse bone marrow-derived cells were cultured with GM-CSF(20 ng/mL).Then,one was added with 100 nmol/L of 25(OH)D3,while the other did not.On day 6.5 μg/mL of BCG was added to stimulate the cells for 24 h.On day 7,suspension cells were harvested for phenotypic and functional analyses.Results:The percentages of CD86 dendritic cells(DCs) in the control group and 25(OH)D3 group were 66.97%± 8.29%and 52.18%± 8.52%.respectively;the mean fluorescence intensities of MHC- Ⅱ in the control group and 25(OH)D3 group were 1 102.16 ± 371.02 and 681.62± 292.71.The expression levels of MHC- Ⅱ and CD86 on the surface of the DCs in 25(OH)D3 group were significantly lower than those of the control group.The ability of the DCs to stimulate proliferation of T-lymphocytes was also significantly lower than that of the control group.Conclusions:These findings suggest that 25(OH)D3 modulates the immune response by affecting the maturation and function of DCs in Mycobacterium tuberculosis period.
文摘The ELISPOT assay is increasingly used for assessing cellular immune responses in clinical trials of HIV-1 or cancer vaccines. However, to date, data from clinical trials do not consistently show that immune responses are correlated with clinical endpoints. This is due in part to the lack of assay standardization and validation across laboratories and therefore, a quality control panel is required to establish competency and comparability amongst different laboratories. In this study peripheral blood mononuclear cells (PBMCs) from healthy individuals were screened and frozen in liquid nitrogen. The recovery and viability of the PBMCs and the frequencies of interferon (IFN)-γ-secreting cells after CEF peptide pool stimulation were detected after various intervals in seven different laboratories. The recovery and viability did not differ significantly after different intervals. Although the frequencies of IFN (interferon)-γ-secreting cells among thawed PBMCs (peripheral blood mononuclear cells) fluctuated after CEF peptide pool stimulation at different intervals, they were not significantly decreased compared with those among fresh PBMCs. However, the viabilities, recoveries and frequencies of IFN-γ-secreting cells differed significantly among the seven laboratories. Our results indicate that cryopreserved PBMCs could be used as a quality control panel for ELISPOT. However, the procedures for ELISPOT need to be standardized amongst different laboratories.
基金Supported by a Municipal Human Resources Development Program for Outstanding Leaders in Medical Disciplines in Shanghai (No.2017BR060)Shanghai Scientific and Technical Innovation Plan 2016 (No.16140900900)
文摘To evaluate the maneuverability and efficacy of phacoemulsification and intraocular lens(IOL) implantation in eyes with corneal opacities after deep anterior lamellar keratoplasty(DALK), twelve eyes of 12 patients with mild to moderate corneal opacities after DALK and coexisting cataracts were analyzed retrospectively. Phacoemulsification and IOL implantation assisted with anterior capsule staining, as well as non-invasive optical fiber illumination, were performed on all eyes. No intraoperative or postoperative complications were noted. Mean corrected distance visual acuity(logMAR) improved from 1.24±0.17 to 0.73±0.22. Post-phaco intraocular pressure was maintained between 13 to 20 mm Hg in all cases throughout the follow-up period. Mean endothelial cell density decreased from 2258.42±205.94 to 1906.25±174.23 cells/mm2. Phacoemulsification and IOL implantation are safe and valid in eyes with mild to moderate corneal opacities after DALK and coexisting cataracts when assisted with anterior capsule staining and non-invasive optical fiber illumination.
基金the National Natural Science Foundation of China(Nos.81874293 and 81630093)for financial support and Major Basic Research Program of Shandong Province(ZR2019ZD26).
文摘Two new quinazoline derivatives versicomides E(1)and F(2),and 10 known compounds(3-12)were isolated from the moss endophytic fungus Aspergillus sp.Their structures were determined on the basis of extensive spectroscopic data analysis and ECD calculations.Among them,the compound 7(6-hydroxy-3-methoxyviridicatin)was first reported as a natural product.Inhibition on LPS-induced NO production in RAW 264.7 murine macrophages found that compounds 5,7 and 8 showed significant inhibitory effects on NO production,with IC50 values of 49.85,22.14 and 46.02μM respectively.
基金supported by the National Natural Science Foundation of China(grant nos.91961201 and 21973116)the Beijing Natural Science Foundation(grant no.2234087)the China Postdoctoral Science Foundation(grant nos.2023T160357 and 2022M721797).
文摘Sensitivity to structure and composition is very challenging to establish in nanocatalysis due to inadequate definition of structures that are very close in composition.We synthesized a pair of atomically precise copper clusters that are very close in composition,[Cu_(20)H_(9)(Tf-dpf)_(10)]·BF4(Cu_(20)H_(9))and[Cu_(20)H_(8)(Tf-dpf)_(10)]·(BF_(4))_(2)(Cu_(20)H_(8)),by using a pyridyl-functionalized flexible amidinate ligand,N,N′-di(5-trifluoromethyl-2-pyridyl)formamidinate.The one-hydride difference in their composition leads to significant variation in geometric and electronic structures and,consequently,distinctly different optical and catalytic properties.Cu_(20)H_(8)exhibits 25 times higher catalytic activity than Cu_(20)H_(9)(96.7%vs 3.7%in yield)in the selective hydrogenation of anα,β-unsaturated aldehyde(cinnamaldehyde)to saturated aldehyde(3-phenylpropanal).Electrospray ionization mass spectrometry combined with density functional theory calculations reveal that the greater ease of dissociation of one Tf-dpf ligand compared to Cu_(20)H_(8)is the key to its higher activity.This work demonstrates a clear case of structure and composition sensitivity in nanocatalysis and that one hydride,out of∼330 atoms in the nanoclusters,can make a huge difference in the catalytic activity.These insights will be useful in the design and synthesis of atomically precise nanocatalysts.
基金This work was supported,in part,by National Key Research and Development Program of China(2017YFC1700400,2017YFC1700404,2022YFC0867400)Natural Science Foundation of China(82125038,81904068,81873209,U1801284,81903821,82174054)+3 种基金the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01 Y036)GDUPS(2019),Natural Science Foundation of Guangdong(2019A1515010909,2021A1515011297)Science and Technology Program of Guangzhou(201903010062,907158833068)the Innovation Team Project of Guangdong Provincial Department of Education(2020KCXTD003).
文摘Myocardial ischemia/reperfusion(/R)injury is a classic type of cardiovascular disease characterized by injury to cardiomyocytes leading to various forms of cell death.It is believed that irreversible myocardial damage resulted from I/R occurs due to oxidative stress evoked during the reperfusion phase.Here we demonstrate that ischemia triggers a specific redox reaction of polyunsaturated fatty acids(PUFA)-phospholipids in myocardial cells,which acts as a priming signaling that initiates the outbreak of robust oxidative damage in the reperfusion phase.Using animal and in vitro models,the crucial lipid species in I/R injury were identifed to be oxidized PUFAs enriched phosphatidylethanolamines.Using multi-omics,arachidonic acid 15-lipoxygenase-1(ALOx15)was identified as the primary mediator of ischemia-provoked phospholipid peroxidation,which was further confirmed using chemogenetic approaches.Collectively,our results reveal that ALOx15 induction in the ischemia phase acts as a"burning point"to ignite phospholipid oxidization into ferroptotic signals.This finding characterizes a novel molecular mechanism for myocardial ischemia injury and offers a potential therapeutic target for early intervention of V/R injury.