RESUMEN
BACKGROUND: Previous studies have suggested that a single dose of rifampin has protective effects against leprosy in close contacts of patients with the disease. Rifapentine was shown to have greater bactericidal activity against Mycobacterium leprae than rifampin in murine models of leprosy, but data regarding its effectiveness in preventing leprosy are lacking. METHODS: We conducted a cluster-randomized, controlled trial to investigate whether single-dose rifapentine is effective in preventing leprosy in household contacts of patients with leprosy. The clusters (counties or districts in Southwest China) were assigned to one of three trial groups: single-dose rifapentine, single-dose rifampin, or control (no intervention). The primary outcome was the 4-year cumulative incidence of leprosy among household contacts. RESULTS: A total of 207 clusters comprising 7450 household contacts underwent randomization; 68 clusters (2331 household contacts) were assigned to the rifapentine group, 71 (2760) to the rifampin group, and 68 (2359) to the control group. A total of 24 new cases of leprosy occurred over the 4-year follow-up, for a cumulative incidence of 0.09% (95% confidence interval [CI], 0.02 to 0.34) with rifapentine (2 cases), 0.33% (95% CI, 0.17 to 0.63) with rifampin (9 cases), and 0.55% (95% CI, 0.32 to 0.95) with no intervention (13 cases). In an intention-to-treat analysis, the cumulative incidence in the rifapentine group was 84% lower than that in the control group (cumulative incidence ratio, 0.16; multiplicity-adjusted 95% CI, 0.03 to 0.87; P = 0.02); the cumulative incidence did not differ significantly between the rifampin group and the control group (cumulative incidence ratio, 0.59; multiplicity-adjusted 95% CI, 0.22 to 1.57; P = 0.23). In a per-protocol analysis, the cumulative incidence was 0.05% with rifapentine, 0.19% with rifampin, and 0.63% with no intervention. No severe adverse events were observed. CONCLUSIONS: The incidence of leprosy among household contacts over 4 years was lower with single-dose rifapentine than with no intervention. (Funded by the Ministry of Health of China and the Chinese Academy of Medical Sciences; Chinese Clinical Trial Registry number, ChiCTR-IPR-15007075.).
Asunto(s)
Leprostáticos , Lepra , Mycobacterium leprae , Rifampin , Humanos , Incidencia , Lepra/epidemiología , Lepra/prevención & control , Lepra/transmisión , Rifampin/administración & dosificación , Rifampin/análogos & derivados , Leprostáticos/administración & dosificación , Leprostáticos/uso terapéutico , Composición FamiliarRESUMEN
The ancestors of chemokines originate in the most primitive of vertebrates, which has recently attracted great interest in the immune functions and the underlying mechanisms of fish chemokines. In the current study, we identified an evolutionarily conserved chemokine, CiCXCL13, from a teleost fish, grass carp. CiCXCL13 was characterized by a typical SCY (small cytokine CXC) domain and four cysteine residues (C34, C36, C61, C77), with the first two cysteines separated by a random amino acid residue, although it shared 24.2-54.8% identity with the counterparts from other vertebrates. CiCXCL13 was an inducible chemokine, whose expression was significantly upregulated in the immune tissues of grass carps after grass carp reovirus infection. CiCXCL13 could bind to the membrane of grass carp head kidney leukocytes and promote cell migration, NO release, and the expression of >15 inflammatory cytokines, including IL-1ß, TNF-α, IL-10 and TGF-ß1, thus regulating the inflammatory response. Mechanistically, CiCXCL13 interacted with its evolutionarily conserved receptor CiCXCR5 and activated the Akt-NF-κB and p38-AP-1 pathways, as well as a previously unrevealed p38-NF-κB pathway, to efficiently induce inflammatory cytokine expression, which was distinct from that reported in mammals. Zebrafish CXCL13 induced inflammatory cytokine expression through Akt, p38, NF-κB, and AP-1 as CiCXCL13. Meanwhile, the CiCXCL13-CiCXCR5 axis-mediated inflammatory activity was negatively shaped by grass carp atypical chemokine receptor 2 (CiACKR2). The present study is, to our knowledge, the first to comprehensively define the immune function of CXCL13 in inflammatory regulation and the underlying mechanism in teleosts, and it provides a valuable perspective on the evolution and biology of fish chemokines.
Asunto(s)
Carpas , Enfermedades de los Peces , Animales , FN-kappa B/metabolismo , Citocinas , Transducción de Señal , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factor de Transcripción AP-1/metabolismo , Pez Cebra/metabolismo , Quimiocinas , Carpas/metabolismo , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Mamíferos/metabolismoRESUMEN
The pathogenesis of COVID-19 is still elusive, which impedes disease progression prediction, differential diagnosis, and targeted therapy. Plasma cell-free RNAs (cfRNAs) carry unique information from human tissue and thus could point to resourceful solutions for pathogenesis and host-pathogen interactions. Here, we performed a comparative analysis of cfRNA profiles between COVID-19 patients and healthy donors using serial plasma. Analyses of the cfRNA landscape, potential gene regulatory mechanisms, dynamic changes in tRNA pools upon infection, and microbial communities were performed. A total of 380 cfRNA molecules were up-regulated in all COVID-19 patients, of which seven could serve as potential biomarkers (AUC > 0.85) with great sensitivity and specificity. Antiviral (NFKB1A, IFITM3, and IFI27) and neutrophil activation (S100A8, CD68, and CD63)-related genes exhibited decreased expression levels during treatment in COVID-19 patients, which is in accordance with the dynamically enhanced inflammatory response in COVID-19 patients. Noncoding RNAs, including some microRNAs (let 7 family) and long noncoding RNAs (GJA9-MYCBP) targeting interleukin (IL6/IL6R), were differentially expressed between COVID-19 patients and healthy donors, which accounts for the potential core mechanism of cytokine storm syndromes; the tRNA pools change significantly between the COVID-19 and healthy group, leading to the accumulation of SARS-CoV-2 biased codons, which facilitate SARS-CoV-2 replication. Finally, several pneumonia-related microorganisms were detected in the plasma of COVID-19 patients, raising the possibility of simultaneously monitoring immune response regulation and microbial communities using cfRNA analysis. This study fills the knowledge gap in the plasma cfRNA landscape of COVID-19 patients and offers insight into the potential mechanisms of cfRNAs to explain COVID-19 pathogenesis.
Asunto(s)
COVID-19 , Ácidos Nucleicos Libres de Células , ARN/sangre , COVID-19/sangre , COVID-19/genética , Ácidos Nucleicos Libres de Células/sangre , Síndrome de Liberación de Citoquinas , Humanos , SARS-CoV-2RESUMEN
[This corrects the article DOI: 10.1371/journal.ppat.1011320.].
RESUMEN
Viral seasonality in the aquaculture industry is an important scientific issue for decades. While the molecular mechanisms underpinning the temperature-dependent pathogenesis of aquatic viral diseases remain largely unknown. Here we report that temperature-dependent activation of IL6-STAT3 signaling was exploited by grass carp reovirus (GCRV) to promote viral entry via increasing the expression of heat shock protein 90 (HSP90). Deploying GCRV infection as a model system, we discovered that GCRV induces the IL6-STAT3-HSP90 signaling activation to achieve temperature-dependent viral entry. Further biochemical and microscopic analyses revealed that the major capsid protein VP7 of GCRV interacted with HSP90 and relevant membrane-associated proteins to boost viral entry. Accordingly, exogenous expression of either IL6, HSP90, or VP7 in cells increased GCRV entry in a dose-dependent manner. Interestingly, other viruses (e.g., koi herpesvirus, Rhabdovirus carpio, Chinese giant salamander iridovirus) infecting ectothermic vertebrates have evolved a similar mechanism to promote their infection. This work delineates a molecular mechanism by which an aquatic viral pathogen exploits the host temperature-related immune response to promote its entry and replication, instructing us on new ways to develop targeted preventives and therapeutics for aquaculture viral diseases.
Asunto(s)
Carpas , Enfermedades de los Peces , Orthoreovirus , Infecciones por Reoviridae , Reoviridae , Animales , Internalización del Virus , Interleucina-6/metabolismo , Infecciones por Reoviridae/metabolismo , Proteínas de la Cápside/metabolismo , Anticuerpos Antivirales/metabolismoRESUMEN
Mitogen-activated protein kinase kinases (MAPKKs) play a critical role in the mitogen-activated protein kinase (MAPK) signaling pathway, transducing external stimuli into intracellular responses and enabling plant adaptation to environmental challenges. Most research has focused on the model plant Arabidopsis (Arabidopsis thaliana). The systematic analysis and characterization of MAPKK genes across different plant species, particularly in cotton (Gossypium hirsutum), are somewhat limited. Here, we identified MAPKK family members from 66 different species, which clustered into 5 different sub-groups, and MAPKKs from four cotton species clustered together. Through further bioinformatic and expression analysis, GhMAPKK5 was identified as the most responsive MAPKK member to salt and drought stress among the 23 MAPKKs identified in Gossypium hirsutum. Silencing GhMAPKK5 in cotton through virus-induced gene silencing (VIGS) led to quicker wilting under salt and drought conditions, while overexpressing GhMAPKK5 in Arabidopsis enhanced root growth and seed germination under these stresses, demonstrating GhMAPKK5's positive role in stress tolerance. Transcriptomics and Yeast-Two-Hybrid assays revealed a MAPK cascade signal module comprising GhMEKK (Mitogen-activated protein kinase kinase kinases)3/8/31-GhMAPKK5-GhMAPK11/23. This signaling cascade may play a role in managing drought and salt stress by regulating transcription factor genes, such as WRKYs, which are involved in the biosynthesis and transport pathways of ABA, proline, and RALF. This study is highly important for further understanding the regulatory mechanism of MAPKK in cotton, contributing to its stress tolerance and offering potential in targets for genetic enhancement.
RESUMEN
The molecular mechanisms controlling organ size during plant development ultimately influence crop yield. However, a deep understanding of these mechanisms is still lacking. UBIQUITIN-SPECIFIC PROTEASE14 (UBP14), encoded by DA3, is an essential factor determining organ size in Arabidopsis (Arabidopsis thaliana). Here, we identified two suppressors of the da3-1 mutant phenotype, namely SUPPRESSOR OF da3-1 1 and 2 (SUD1 and SUD2), which encode the E3 ligases MOS4-ASSOCIATED COMPLEX 3A (MAC3A) and MAC3B, respectively. The mac3a-1 and mac3b-1 mutations partially suppressed the high ploidy level and organ size phenotypes observed in the da3-1 mutant. Biochemical analysis showed that MAC3A and MAC3B physically interacted with and ubiquitinated UBP14/DA3 to modulate its stability. We previously reported that UBP14/DA3 acts upstream of the B-type cyclin-dependent kinase CDKB1;1 and maintains its stability to inhibit endoreduplication and cell growth. In this work, MAC3A and MAC3B were found to promote the degradation of CDKB1;1 by ubiquitinating UBP14/DA3. Genetic analysis suggests that MAC3A and MAC3B act in a common pathway with UBP14/DA3 to control endoreduplication and organ size. Thus, our findings define a regulatory module, MAC3A/MAC3B-UBP14-CDKB1;1, that plays a critical role in determining organ size and endoreduplication in Arabidopsis.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ligasas/metabolismo , Tamaño de los Órganos , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare inflammatory disease categorized as antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. The majority of patients are ANCA-positive, predominantly against myeloperoxidase (MPO). Previous studies have predominantly concentrated on the association between EGPA and neutrophils, but recent research has emphasized the role of lymphocytes in the development of EGPA. The objective of our research was to examine the causal association between immune cells and MPO + ANCA EGPA. A two-sample bidirectional Mendelian randomization (MR) analysis was performed, which included 159 MPO + ANCA EGPA cases and 6688 controls and utilized Genome-Wind Associaton Studies (GWAS) summary statistics of immune traits from approximately 3757 individuals, encompassing around 22 million single nucleotide polymorphisms (SNPs). Our findings revealed that 23 immunophenotypes were associated with MPO + ANCA EGPA. Furthermore, the reverse MR analysis showed that MPO + ANCA EGPA had significant causal effects on three immunophenotypes within the Treg panel. By integrating existing research, our study unveiled the contributions of Tregs, B cells, and monocytes to the development of EGPA. Subgroup analysis specifically examined the roles of lymphocyte subtypes, cytokines, and their surface molecules in the pathogenic mechanisms of the disease. This comprehensive approach provides a novel perspective on the biological mechanisms and early intervention strategies for MPO + ANCA EGPA by focusing on immune cells.
Asunto(s)
Vasculitis Asociada a Anticuerpos Citoplasmáticos Antineutrófilos , Anticuerpos Anticitoplasma de Neutrófilos , Análisis de la Aleatorización Mendeliana , Peroxidasa , Polimorfismo de Nucleótido Simple , Humanos , Peroxidasa/genética , Peroxidasa/inmunología , Vasculitis Asociada a Anticuerpos Citoplasmáticos Antineutrófilos/genética , Vasculitis Asociada a Anticuerpos Citoplasmáticos Antineutrófilos/inmunología , Anticuerpos Anticitoplasma de Neutrófilos/inmunología , Estudio de Asociación del Genoma Completo , Linfocitos T Reguladores/inmunología , Linfocitos B/inmunologíaRESUMEN
BACKGROUND: Soil salinity is one of the major abiotic stresses that threatens crop growth. Cotton has some degree of salt tolerance, known as the "pioneer crop" of saline-alkali land. Cultivation of cotton is of great significance to the utilization of saline-alkali land and the development of cotton industry. Gossypium hirsutum and G. barbadense, as two major cotton species, are widely cultivated worldwide. However, until recently, the regulatory mechanisms and specific differences of their responses to salt stress have rarely been reported. RESULTS: In this study, we comprehensively compared the differences in the responses of G. hirsutum acc. TM-1 and G. barbadense cv. Hai7124 to salt stress. The results showed that Hai7124 exhibited better growth than did TM-1 under salt stress, with greater PRO content and antioxidant capability, whereas TM-1 only presented greater K+ content. Transcriptome analysis revealed significant molecular differences between the two cotton species in response to salt stress. The key pathways of TM-1 induced by salt are mainly related to growth and development, such as porphyrin metabolism, DNA replication, ribosome and photosynthesis. Conversely, the key pathways of Hai7124, such as plant hormone signal transduction, MAPK signaling pathway-plant, and phenylpropanoid biosynthesis, are mainly related to plant defense. Further comparative analyses of differentially expressed genes (DEGs) revealed that antioxidant metabolism, abscisic acid (ABA) and jasmonic acid (JA) signalling pathways were more strongly activated in Hai7124, whereas TM-1 was more active in K+ transporter-related genes and ethylene (ETH) signalling pathway. These differences underscore the various molecular strategies adopted by the two cotton species to navigate through salt stress, and Hai7124 responded more strongly to salt stress, which explains the potential reasons for the greater salt tolerance of Hai7124. Finally, we identified 217 potential salt tolerance-related genes, 167 of which overlapped with the confidence intervals of significant SNPs identified in previous genome-wide association studies (GWASs), indicating the high reliability of these genes. CONCLUSIONS: These findings provide new insights into the differences in the regulatory mechanisms of salt tolerance between G. hirsutum and G. barbadense, and identify key candidate genes for salt tolerance molecular breeding in cotton.
Asunto(s)
Gossypium , Estrés Salino , Tolerancia a la Sal , Gossypium/genética , Gossypium/fisiología , Gossypium/crecimiento & desarrollo , Tolerancia a la Sal/genética , Estrés Salino/genética , Transcriptoma , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Especificidad de la EspecieRESUMEN
BACKGROUND: The interleukin-17 (IL-17) signaling pathway is intricately linked with immunity and inflammation; however, the association between the IL-17 signaling pathway and skeletal muscle inflammation remains poorly understood. The study aims to investigate the role of the IL-17 signaling pathway in skeletal muscle inflammation and to evaluate the therapeutic potential of anti-IL-17 antibodies in reducing muscle inflammation. METHODS: A skeletal muscle inflammation model was induced by cardiotoxin (CTX) injection in C57BL6/J mice. Following treatment with an anti-IL-17 antibody, we conducted a comprehensive analysis integrating single-cell RNA sequencing (scRNA-seq), bioinformatics, enzyme-linked immunosorbent assay (ELISA), immunofluorescence, and Western blot techniques to elucidate underlying mechanisms. RESULTS: scRNA-seq analysis revealed a significant increase in neutrophil numbers and activity in inflamed skeletal muscle compared to other cell types, including macrophages, T cells, B cells, endothelial cells, fast muscle cells, fibroblasts, and skeletal muscle satellite cells. The top 30 differentially expressed genes within neutrophils, along with 55 chemokines, were predominantly enriched in the IL-17 signaling pathway. Moreover, the IL-17 signaling pathway exhibited heightened expression in inflamed skeletal muscle, particularly within neutrophils. Treatment with anti-IL-17 antibody resulted in the suppression of IL-17 signaling pathway expression, accompanied by reduced levels of pro-inflammatory cytokines IL-1ß, IL-6, and TNF-α, as well as decreased numbers and activity of Ly6g+/Mpo+ neutrophils compared to CTX-induced skeletal muscle inflammation. CONCLUSION: Our findings suggest that the IL-17 signaling pathway plays a crucial role in promoting inflammation within skeletal muscle. Targeting this pathway may hold promise as a therapeutic strategy for ameliorating the inflammatory micro-environment and reducing cytokine production.
Asunto(s)
Inflamación , Interleucina-17 , Ratones Endogámicos C57BL , Músculo Esquelético , Transducción de Señal , Animales , Transducción de Señal/efectos de los fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/patología , Ratones , Interleucina-17/metabolismo , Inflamación/metabolismo , Inflamación/patología , Masculino , Neutrófilos/metabolismo , Neutrófilos/inmunología , Miositis/metabolismo , Miositis/tratamiento farmacológico , Miositis/inmunologíaRESUMEN
Oxygen deprivation caused by flooding activates acclimation responses to stress and restricts plant growth. After experiencing flooding stress, plants must restore normal growth; however, which genes are dynamically and precisely controlled by flooding stress remains largely unknown. Here, we show that the Arabidopsis thaliana ubiquitin E3 ligase SUBMERGENCE RESISTANT1 (SR1) regulates the stability of the transcription factor WRKY33 to modulate the submergence response. SR1 physically interacts with WRKY33 in vivo and in vitro and controls its ubiquitination and proteasomal degradation. Both the sr1 mutant and WRKY33 overexpressors exhibited enhanced submergence tolerance and enhanced expression of hypoxia-responsive genes. Genetic experiments showed that WRKY33 functions downstream of SR1 during the submergence response. Submergence induced the phosphorylation of WRKY33, which enhanced the activation of RAP2.2, a positive regulator of hypoxia-response genes. Phosphorylated WRKY33 and RAP2.2 were degraded by SR1 and the N-degron pathway during reoxygenation, respectively. Taken together, our findings reveal that the on-and-off module SR1-WRKY33-RAP2.2 is connected to the well-known N-degron pathway to regulate acclimation to submergence in Arabidopsis. These two different but related modulation cascades precisely balance submergence acclimation with normal plant growth.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteolisis , Factores de Transcripción/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Oscuridad , Epistasis Genética , Regulación de la Expresión Génica de las Plantas , Modelos Biológicos , Fosforilación , Unión Proteica , UbiquitinaciónRESUMEN
A palladium-catalyzed radical Heck-type coupling reaction of cyclobutanone oxime esters with olefins under visible-light irradiation has been developed. The cyanoalkyl/Pd(I) hybrid species generated by selected ring-opening C-C bond cleavage of imino/Pd(I) species reacted smoothly with vinyl arenes, delivering the cyanoalkylation olefins under mild conditions. This elegant strategy has a broad scope and functional group tolerance. Subsequently, late-stage functionalization of bioactive molecules and synthetic transformations of the product further confirm the practicality.
RESUMEN
Grass carp reovirus (GCRV) infections and hemorrhagic disease (GCHD) outbreaks are typically seasonally periodic and temperature-dependent, yet the molecular mechanism remains unclear. Herein, we depicted that temperature-dependent IL-6/STAT3 axis was exploited by GCRV to facilitate viral replication via suppressing type â IFN signaling. Combined multi-omics analysis and qPCR identified IL-6, STAT3, and IRF3 as potential effector molecules mediating GCRV infection. Deploying GCRV challenge at 18 °C and 28 °C as models of resistant and permissive infections and switched to the corresponding temperatures as temperature stress models, we illustrated that IL-6 and STAT3 expression, genome level of GCRV, and phosphorylation of STAT3 were temperature dependent and regulated by temperature stress. Further research revealed that activating IL-6/STAT3 axis enhanced GCRV replication and suppressed the expression of IFNs, whereas blocking the axis impaired viral replication. Mechanistically, grass carp STAT3 inhibited IRF3 nuclear translocation via interacting with it, thus down-regulating IFNs expression, restraining transcriptional activation of the IFN promoter, and facilitating GCRV replication. Overall, our work sheds light on an immune evasion mechanism whereby GCRV facilitates viral replication by hijacking IL-6/STAT3 axis to down-regulate IFNs expression, thus providing a valuable reference for targeted prevention and therapy of GCRV.
Asunto(s)
Carpas , Enfermedades de los Peces , Interferón Tipo I , Interleucina-6 , Infecciones por Reoviridae , Reoviridae , Factor de Transcripción STAT3 , Transducción de Señal , Replicación Viral , Animales , Enfermedades de los Peces/inmunología , Enfermedades de los Peces/virología , Interleucina-6/genética , Interleucina-6/inmunología , Interleucina-6/metabolismo , Infecciones por Reoviridae/inmunología , Infecciones por Reoviridae/veterinaria , Reoviridae/fisiología , Carpas/inmunología , Carpas/genética , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Factor de Transcripción STAT3/inmunología , Transducción de Señal/inmunología , Interferón Tipo I/inmunología , Interferón Tipo I/genética , Proteínas de Peces/genética , Proteínas de Peces/inmunología , Inmunidad Innata/genéticaRESUMEN
Cyclic desulfurization-regeneration-denitrification based on metal-free carbon materials is one of the most promising ways to remove NOx and SO2 simultaneously. However, the impact of S-doping induced by the cyclic desulfurization and regeneration (C-S-R) process on the selective catalytic reduction (SCR) is not well understood. Herein, it is demonstrated that the C-S-R process at 500 °C induces in situ S-doping with a significant accumulation of C-S-C structures. NOx conversion was dramatically enhanced from 18.95% of the original sample to 84.55% of the S-doped sample. Density functional theory calculations revealed that the C-S-C structure significantly regulates the electronic structure of the C atom adjacent to the ketonic carbonyl group, thereby significantly altering the NH3 adsorption configuration with superior adsorption capacity. Moreover, S-doping induces an extra electron transfer between the N atom of the NH3 molecule and the C atom of the carbon plane, thereby promoting the activation of NH3 over the ketonic carbonyl group with a reduced energy barrier. This study elucidates a synergetic promotional mechanism between the ketonic carbonyl group and the C-S-C structure for SCR, offering a novel design strategy for high-performance heteroatom-doped carbon catalysts in industrial applications.
Asunto(s)
Amoníaco , Carbono , Oxidación-Reducción , Amoníaco/química , Metales , Titanio , CatálisisRESUMEN
The byproduct formation in environmental catalysis is strongly influenced by the chemical state and coordination of catalysts. Herein, two Pd/CeO2 catalysts (PdCe-350 and PdCe-800) with varying oxygen vacancies (Ov) and coordination numbers (CN) of Pd were prepared to investigate the mechanism of N2O and NH3 formation during NO reduction by CO. PdCe-350 exhibits a higher density of Ov and Pd sites with higher CN, leading to an enhanced metal-support interaction by electron transformation from the support to Pd. Consequently, PdCe-350 displayed increased levels of byproduct formation. In situ spectroscopies under dry and wet conditions revealed that at low temperatures, the N2O formation strongly correlated with the Ov density through the decomposition of chelating nitro species on PdCe-350. Conversely, at high temperatures, it was linked to the reactivity of Pd species, primarily facilitated by monodentate nitrates on PdCe-800. In terms of NH3 formation, its occurrence was closely associated with the activation of H2O and C3H6, since a water-gas shift or hydrocarbon reforming could provide hydrogen. Both bridging and monodentate nitrates showed activity in NH3 formation, while hyponitrites were identified as key intermediates for both catalysts. The insights provide a fundamental understanding of the intricate relationship among the local coordination of Pd, surface Ov, and byproduct distribution.
Asunto(s)
Oxígeno , Agua , Oxidación-Reducción , Análisis Espectral , Nitratos/química , CatálisisRESUMEN
Transforming hazardous species into active sites by ingenious material design was a promising and positive strategy to improve catalytic reactions in industrial applications. To synergistically address the issue of sluggish CO2 desorption kinetics and SO2-poisoning solvent of amine scrubbing, we propose a novel method for preparing a high-performance core-shell C@Mn3O4 catalyst for heterogeneous sulfur migration and in situ reconstruction to active -SO3H groups, and thus inducing an enhanced proton-coupled electron transfer (PCET) effect for CO2 desorption. As anticipated, the rate of CO2 desorption increases significantly, by 255%, when SO2 is introduced. On a bench scale, dynamic CO2 capture experiments reveal that the catalytic regeneration heat duty of SO2-poisoned solvent experiences a 32% reduction compared to the blank case, while the durability of the catalyst is confirmed. Thus, the enhanced PCET of C@Mn3O4, facilitated by sulfur migration and simultaneous transformation, effectively improves the SO2 resistance and regeneration efficiency of amine solvents, providing a novel route for pursuing cost-effective CO2 capture with an amine solvent.
Asunto(s)
Dióxido de Carbono , Protones , Electrones , Solventes , Aminas , AzufreRESUMEN
Tandem catalysis is widely adopted for multipollutant control in mobile sources but has rarely been reported in stationary source emission elimination. This work proposed a tandem arrangement way with up-streamed V2O5/TiO2 + down-streamed Cr2O3/TiO2 catalysts, which could achieve the efficient synergistic control of NOx and C3H8 in industrial flue gas. Moreover, this arrangement successfully alleviated the unwanted N2O formation during the NH3 -SCR process. Compared to the conventional impregnation method of the Cr2O3-V2O5/TiO2 catalyst, the tandem catalysts of V2O5/TiO2 + Cr2O3/TiO2 could enhance the NOx and C3H8 conversion by 4.2% and 39.5%, respectively, at 350 °C. It might be attributed to the fact that Cr species was the active site for C3H8 oxidation, and the tandem arrangement of catalysts was beneficial to even dispersion of active components on supports. Furthermore, due to the preferential NOx removal over the up-streamed V2O5/TiO2 catalyst, the tandem catalysts obviously alleviated the N2O formation caused by Cr species during the NH3-SCR process. Herein, it significantly decreased N2O formation by 240.5% at 350 °C compared to the Cr2O3-V2O5/TiO2 catalyst, achieving multipollutant emission control from industrial flue gas with the performance of "one stone three birds".
RESUMEN
Carbon materials are regarded as a promising adsorbent for the adsorption of volatile organic compounds (VOCs). However, their adsorption behaviors are usually compromised at ambient conditions, attributed to the competitive VOCs adsorption with water vapor. In this study, we demonstrated that the selectivity for toluene than water of carbon can be effectively enhanced by introducing more sp2-carbon with two-dimensional nanosheets stacked. The multilayer carbon nanosheets enriched with sp2-carbon (CNS-MCA) exhibit a 151° H2O-contact angle, indicating hydrophobicity. Dynamic adsorption behaviors revealed that CNS-MCA retain 71% of their toluene adsorption capacity (91 mg/g) even at 60% relative humidity. Density functional theory (DFT) calculations, static adsorption studies, in situ Raman spectroscopy, and time-resolved in situ nuclear magnetic resonance (NMR) spectroscopy collectively indicate that toluene exhibits enhanced adsorption and selectivity due to π-π* interactions between its aromatic rings and the sp2-carbon. Conversely, water adsorption is attenuated, attributed to the reduced availability of surface-exposed hydrogen bonds associated with sp2-carbon and the inherent hydrophobic nature of multilayer graphene. This study extends a novel solution for the enhancement of VOCs adsorption under humid conditions.
RESUMEN
The impact of water on catalyst activity remains inconclusive due to its dependence on the specific reaction environment. To maximize the exploitation of water's promoting effect, we employed ammonia selective catalytic reduction (NH3-SCR) as a probe reaction and proposed a phosphorus modification strategy for Cu-ZSM-5 catalysts. The objective of this approach was to construct water-adaptive microstructures through directional arrangement. To investigate the effect of phosphorus on the transformation of framework copper sites in humid environments, we conducted comprehensive characterizations and density functional theory calculation. Results reveal that water molecules cleave the oxygen bridges between phosphorus oxide and copper, leading to the formation of active isolated [Cu(OH)]+ groups and phosphate. The phosphate species weaken the interaction between exchanged Cu2+ groups and the zeolite framework, leading to the generation of highly migratory hydrated Cu2+ species. This work will potentially guide the rational design of water-adaptive catalysts for gas pollution abatement in a humid environment.
RESUMEN
BACKGROUND: Membranous nephropathy (MN) is a common type of nephrotic syndrome (NS) in adults, accounting for about 20-30% of cases. Although secondary to specific factors, the coexistence of MN and mantle cell lymphoma (MCL) has been scarcely reported in clinical literature. CASE PRESENTATION: A 59-year-old Chinese male was admitted to the hospital with a generalized pruritic rash with bilateral lower extremity edema, which did not improve significantly after symptomatic treatment. He had undergone renal biopsy, and the diagnosis was thought to be secondary MN (SMN), therefore, we did a lymph node biopsy on the patient and found that MN was complicated with MCL. Soon after, the patient was admitted to the hematology department for a BR chemotherapy regimen (composed of bendamustine 90 mg/m2 BSA (body surface area), rituximab 375 mg/m2 BSA and dexamethasone 5 mg), and during the post-treatment follow-up, both his symptoms and renal function improved. CONCLUSIONS: The mechanism underlying the combination of SMN and MCL remains elusive and exceedingly rare, consequently often overlooked in clinical practice. This case serves to offer valuable clinical insights for diagnosis and treatment, while emphasizing the pivotal role of renal pathology in clinical assessment.