Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental ...Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental investigation is important in correlating the catalytic activity and the products.In this work,a spatial resolution online mass spectrometry(MS)system was developed and applied to a Mn-Na_(2)WO_(4)/SiO_(2) catalyzed OCM system.In addition to the residue gas analysis,the system obtained the distribution information of the reactants and products in the reactor.At various setting temperatures,all species online MS signals were collected at different positions,mapping the reaction activity covering parameters including temperature,time and space.The distribution behavior of the catalytic activity,selectivity,and apparent activation energy were kinetically analyzed.Selectivity and additional carbon balance analysis strongly supported the radical coupling model of OCM and indicated that after the catalytic bed layer,there is a significant length in the reactor(>2 mm)filled with radicals.Based on the result,a designed new method by tuning the temperature field in the reactor was found effectively to improve the catalytic activity,especially the C_(2) yield from 702 to 773℃.展开更多
Detailed knowledge on tissue-specific metabolic reprogramming in diabetic nephropathy(DN)is vital for more accurate understanding the molecular pathological signature and developing novel therapeutic strategies.In the...Detailed knowledge on tissue-specific metabolic reprogramming in diabetic nephropathy(DN)is vital for more accurate understanding the molecular pathological signature and developing novel therapeutic strategies.In the present study,a spatial-resolved metabolomics approach based on air flowassisted desorption electrospray ionization(AFADESI)and matrix-assisted laser desorption ionization(MALDI)integrated mass spectrometry imaging(MSI)was proposed to investigate tissue-specific metabolic alterations in the kidneys of high-fat diet-fed and streptozotocin(STZ)-treated DN rats and the therapeutic effect of astragalosideⅣ,a potential anti-diabetic drug,against DN.As a result,a wide range of functional metabolites including sugars,amino acids,nucleotides and their derivatives,fatty acids,phospholipids,sphingolipids,glycerides,carnitine and its derivatives,vitamins,peptides,and metal ions associated with DN were identified and their unique distribution patterns in the rat kidney were visualized with high chemical specificity and high spatial resolution.These region-specific metabolic disturbances were ameliorated by repeated oral administration of astragaloside Ⅳ(100 mg/kg)for 12 weeks.This study provided more comprehensive and detailed information about the tissue-specific metabolic reprogramming and molecular pathological signature in the kidney of diabetic rats.These findings highlighted the promising potential of AFADESI and MALDI integrated MSI based metabolomics approach for application in metabolic kidney diseases.展开更多
Gastric Carcinoma(GC)is a highly fatal malignant tumor with a poor prognosis.Its elevated mortality rates are primarily due to its proclivity for late-stage metastasis.Exploring the metabolic interactions between tumo...Gastric Carcinoma(GC)is a highly fatal malignant tumor with a poor prognosis.Its elevated mortality rates are primarily due to its proclivity for late-stage metastasis.Exploring the metabolic interactions between tumor microenvironment and the systemic bloodstream could help to clearly understand the mechanisms and identify precise biomarkers of tumor growth,proliferation,and metastasis.In this study,an integrative approach that combines plasma metabolomics with mass spectrometry imaging of tumor tissue was developed to investigate the global metabolic landscape of GC tumorigenesis and metastasis.The results showed that the oxidized glutathione to glutathione ratio(GSSH/GSH)became increased in non-distal metastatic GC(M0),which means an accumulation of oxidative stress in tumor tissues.Furthermore,it was found that the peroxidation of polyunsaturated fatty acids,such as 9,10-EpOMe,9-HOTrE,etc.,were accelerated in both plasma and tumor tissues of distal metastatic GC(M1).These changes were further confirmed the potential effect of CYP2E1 and GGT1 in metastatic potential of GC by mass spectrometry imaging(MSI)and immunohistochemistry(IHC).Collectively,our findings reveal the integrated multidimensional metabolomics approach is a clinical useful method to unravel the bloodtumor metabolic crosstalk,illuminate reprogrammed metabolic networks,and provide reliable circulating biomarkers.展开更多
A novel laser-assisted pulsed plasma thruster(LA-PPT)is proposed as an electric propulsion thruster,which separates laser ablation and electromagnetic acceleration.It aims for a higher specific impulse than that achie...A novel laser-assisted pulsed plasma thruster(LA-PPT)is proposed as an electric propulsion thruster,which separates laser ablation and electromagnetic acceleration.It aims for a higher specific impulse than that achieved with conventional LA-PPTs.Owing to the short-time discharge and the novel configuration,the physical mechanism of the discharge is unclear.Time and spatial-resolved optical emission spectroscopy was applied to investigate the variation in the plasma properties in the thruster discharge channel.The plasma species,electron temperature,and electron density were obtained and discussed.Our investigation revealed that there were H_(α),H_(β),H_(γ),H_(ε) atoms,CⅠ,CⅡ,CⅢ,CⅣ,ClⅠ,ClⅡparticles,and a small amount of CH,C_(3),C_(2),H_(2) neutral molecular groups in the plasma.The electron temperature of the discharge channel of the thruster was within 0.6–4.9 e V,and the electron density was within(1.1–3.0)×10^(18)cm^(-3),which shows that the optical emission spectroscopy method is to measure the electron excitation temperature and electron density in heavy particles.But the Langmuir probe method is to measure the temperature and density of free electrons.The use of laser instead of spark plug as the ignition mode significantly changed the plasma distribution in the discharge channel.Unlike the conventional PPT,which has high electron density near the thruster surface,LAPPT showed relatively large electron density at the thruster outlet,which increased the thruster specific impulse.In addition,the change in the ignition mode enabled the electron density in the LA-PPT discharge channel to be higher than that in the conventional PPT.This proves that the ignition mode with laser replacing the spark plug effectively optimised the PPT performance.展开更多
文摘Oxidative coupling of methane(OCM)is a catalytic partial oxidation process that directly converts methane into C_(2) products.For this high temperature reaction,understanding the radical behavior through experimental investigation is important in correlating the catalytic activity and the products.In this work,a spatial resolution online mass spectrometry(MS)system was developed and applied to a Mn-Na_(2)WO_(4)/SiO_(2) catalyzed OCM system.In addition to the residue gas analysis,the system obtained the distribution information of the reactants and products in the reactor.At various setting temperatures,all species online MS signals were collected at different positions,mapping the reaction activity covering parameters including temperature,time and space.The distribution behavior of the catalytic activity,selectivity,and apparent activation energy were kinetically analyzed.Selectivity and additional carbon balance analysis strongly supported the radical coupling model of OCM and indicated that after the catalytic bed layer,there is a significant length in the reactor(>2 mm)filled with radicals.Based on the result,a designed new method by tuning the temperature field in the reactor was found effectively to improve the catalytic activity,especially the C_(2) yield from 702 to 773℃.
基金supported by the National Natural Science Foundation of China(No.81803483,No.21927808)National Key Research and Development Program of China(No.2017YFC1704006)。
文摘Detailed knowledge on tissue-specific metabolic reprogramming in diabetic nephropathy(DN)is vital for more accurate understanding the molecular pathological signature and developing novel therapeutic strategies.In the present study,a spatial-resolved metabolomics approach based on air flowassisted desorption electrospray ionization(AFADESI)and matrix-assisted laser desorption ionization(MALDI)integrated mass spectrometry imaging(MSI)was proposed to investigate tissue-specific metabolic alterations in the kidneys of high-fat diet-fed and streptozotocin(STZ)-treated DN rats and the therapeutic effect of astragalosideⅣ,a potential anti-diabetic drug,against DN.As a result,a wide range of functional metabolites including sugars,amino acids,nucleotides and their derivatives,fatty acids,phospholipids,sphingolipids,glycerides,carnitine and its derivatives,vitamins,peptides,and metal ions associated with DN were identified and their unique distribution patterns in the rat kidney were visualized with high chemical specificity and high spatial resolution.These region-specific metabolic disturbances were ameliorated by repeated oral administration of astragaloside Ⅳ(100 mg/kg)for 12 weeks.This study provided more comprehensive and detailed information about the tissue-specific metabolic reprogramming and molecular pathological signature in the kidney of diabetic rats.These findings highlighted the promising potential of AFADESI and MALDI integrated MSI based metabolomics approach for application in metabolic kidney diseases.
基金financial support from the National Key R&D Program of China(No.2022YFC3401003)the National Natural Science Foundation of China(Nos.21927808,82073817,22104160)。
文摘Gastric Carcinoma(GC)is a highly fatal malignant tumor with a poor prognosis.Its elevated mortality rates are primarily due to its proclivity for late-stage metastasis.Exploring the metabolic interactions between tumor microenvironment and the systemic bloodstream could help to clearly understand the mechanisms and identify precise biomarkers of tumor growth,proliferation,and metastasis.In this study,an integrative approach that combines plasma metabolomics with mass spectrometry imaging of tumor tissue was developed to investigate the global metabolic landscape of GC tumorigenesis and metastasis.The results showed that the oxidized glutathione to glutathione ratio(GSSH/GSH)became increased in non-distal metastatic GC(M0),which means an accumulation of oxidative stress in tumor tissues.Furthermore,it was found that the peroxidation of polyunsaturated fatty acids,such as 9,10-EpOMe,9-HOTrE,etc.,were accelerated in both plasma and tumor tissues of distal metastatic GC(M1).These changes were further confirmed the potential effect of CYP2E1 and GGT1 in metastatic potential of GC by mass spectrometry imaging(MSI)and immunohistochemistry(IHC).Collectively,our findings reveal the integrated multidimensional metabolomics approach is a clinical useful method to unravel the bloodtumor metabolic crosstalk,illuminate reprogrammed metabolic networks,and provide reliable circulating biomarkers.
基金supported by National Natural Science Foundation of China(No.11772354)。
文摘A novel laser-assisted pulsed plasma thruster(LA-PPT)is proposed as an electric propulsion thruster,which separates laser ablation and electromagnetic acceleration.It aims for a higher specific impulse than that achieved with conventional LA-PPTs.Owing to the short-time discharge and the novel configuration,the physical mechanism of the discharge is unclear.Time and spatial-resolved optical emission spectroscopy was applied to investigate the variation in the plasma properties in the thruster discharge channel.The plasma species,electron temperature,and electron density were obtained and discussed.Our investigation revealed that there were H_(α),H_(β),H_(γ),H_(ε) atoms,CⅠ,CⅡ,CⅢ,CⅣ,ClⅠ,ClⅡparticles,and a small amount of CH,C_(3),C_(2),H_(2) neutral molecular groups in the plasma.The electron temperature of the discharge channel of the thruster was within 0.6–4.9 e V,and the electron density was within(1.1–3.0)×10^(18)cm^(-3),which shows that the optical emission spectroscopy method is to measure the electron excitation temperature and electron density in heavy particles.But the Langmuir probe method is to measure the temperature and density of free electrons.The use of laser instead of spark plug as the ignition mode significantly changed the plasma distribution in the discharge channel.Unlike the conventional PPT,which has high electron density near the thruster surface,LAPPT showed relatively large electron density at the thruster outlet,which increased the thruster specific impulse.In addition,the change in the ignition mode enabled the electron density in the LA-PPT discharge channel to be higher than that in the conventional PPT.This proves that the ignition mode with laser replacing the spark plug effectively optimised the PPT performance.
