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Photoelectrochemical (PEC) carbon dioxide (CO2) reduction (CO2R) holds the potential to reduce the costs of solar fuel production by integrating CO2 utilization and light harvesting within one integrated device. However, the CO2R selectivity on the photocathode is limited by the lack of catalytic active sites and competition with the hydrogen evolution reaction. On the other hand, serious parasitic light absorption occurs on the front-side-illuminated photocathode due to the poor light transmittance of CO2R cocatalyst films, resulting in extremely low photocurrent density at the CO2R equilibrium potential. This paper describes the design and fabrication of a photocathode consisting of crystal phase-modulated Ag nanocrystal cocatalysts integrated on illumination-reaction decoupled heterojunction silicon (Si) substrate for the selective and efficient conversion of CO2. Ag nanocrystals containing unconventional hexagonal close-packed phases accelerate the charge transfer process in CO2R reaction, exhibiting excellent catalytic performance. Heterojunction Si substrate decouples light absorption from the CO2R catalyst layer, preventing the parasitic light absorption. The obtained photocathode exhibits a carbon monoxide (CO) Faradaic efficiency (FE) higher than 90% in a wide potential range, with the maximum FE reaching up to 97.4% at -0.2 V vs. reversible hydrogen electrode. At the CO2/CO equilibrium potential, a CO partial photocurrent density of -2.7 mA cm-2 with a CO FE of 96.5% is achieved in 0.1 M KHCO3 electrolyte on this photocathode, surpassing the expensive benchmark Au-based PEC CO2R system.
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Electrochemical conversion of N2 into ammonia presents a sustainable pathway to produce hydrogen storage carrier but yet requires further advancement in electrocatalyst design and electrolyzer integration. This technology suffers from low selectivity and yield owing to the extremely strong N≡N bond and the exceptionally low solubility of N2 in aqueous systems. A high NH3 synthesis performance is restricted by the high activation energy of N≡N bond and the supply insufficiency of N2 to active sites. This paper describes the introduction of electron-rich Bi0 sites into Ag catalysts with a high-pressure electrolyzer that enables a dramatically enhanced Faradaic efficiency of 44.0% and yield of 28.43 µg cm-2 h-1 at 4.0 MPa. Combined with density functional theory results, in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy demonstrates that N2 reduction reaction follows an associative mechanism, in which a high coverage of N-N bond and -NH2 intermediates suggest electron-rich Bi0 boosts sound activation of N2 molecules and low hydrogenation barrier. The proposed strategy of engineering electrochemical catalysts and devices provides powerful guidelines for achieving industrial-level green ammonia production.
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Solar water splitting is regarded as holding great potential for clean fuels production. However, the efficiency of charge separation/transfer of photocatalysts is still too low for industrial application. This paper describes the synthesis of a Pt-Au binary single-site loaded g-C3N4 nanosheet photocatalyst inspired by the concept of the dipole. The existent larger charge imbalance greatly enhanced the localized molecular dipoles over adjacent Pt-Au sites in contrast to the unary counterparts. The superposition of molecular dipoles then further strengthened the internal electric field and thus promoted the charge transportation dynamics. In the modeling photocatalytic hydrogen evolution, the optimal Pt-Au binary site photocatalysts (0.25% loading) showed 4.9- and 2.3-fold enhancement of performance compared with their Pt and Au single-site counterparts, respectively. In addition, the reaction barrier over the Pt-Au binary sites was lowered, promoting the hydrogen evolution process. This work offers a valuable strategy for improving photocatalytic charge transportation dynamics by constructing polynary single sites.
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Single Atoms Catalysts (SACs) have emerged as a class of highly promising heterogeneous catalysts, where the traditional bottom-up synthesis approaches often encounter considerable challenges in relation to aggregation issues and poor stability. Consequently, achieving densely dispersed atomic species in a reliable and efficient manner remains a key focus in the field. Herein, we report a new facile electrochemical knock-down strategy for the formation of SACs, whereby the metal Zn clusters are transformed into single atoms. While a defect-rich substrate plays a pivotal role in capturing and stabilizing isolated Zn atoms, the feasibility of this novel strategy is demonstrated through a comprehensive investigation, combining experimental and theoretical studies. Furthermore, when studied in exploring for potential applications, the material prepared shows a remarkable improvement of 58.21% for the Li+ storage and delivers a capacity over 300 Wh kg-1 after 500 cycles upon the transformation of Zn clusters into single atoms.
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A prominent feature of modern electrochemical technologies, such as fuel cells and electrolysis, is the employing of polyelectrolytes instead of liquid electrolytes. Unlike the well-studied electrode/liquid electrolyte interfaces, however, the catalytic characteristics of electrode/polyelectrolyte interfaces remain largely unexplored, mostly due to the lack of reliable probing methods. Herein, we report a universally applicable approach to investigating electrocatalytic reactions at electrode/polyelectrolyte interfaces under normal electrochemical conditions. By coating a thin layer of anion-exchange membrane (AEM) onto the electrode surface, solutions with bulky organic cations were well separated, thus a pure electrode/polyelectrolyte interface can be established in a regular electrochemical setup and studied using in situ spectroscopies, e.g., attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS). We found that the blank Au surface was inert toward the CO2 reduction reaction (CO2RR) in the absence of alkali metal cations, whereas coating with an AEM can dramatically turn on the catalytic activity. ATR-SEIRAS revealed that the hydrogen bond network of water at the Au/AEM interface was enhanced in comparison to that on the blank Au surface, which facilitated the hydrogenation process of the CO2RR. These findings further our fundamental understanding of the catalytic behavior of electrode/polyelectrolyte interfaces and benefit the development of relevant electrochemical technologies.
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Electrochemical CO reduction reaction (CORR) offers a promising approach for sustainable acetate production, the promotion of which requires the control of multiple protonation steps. This paper describes the synthesis of atomically isolated Pd sites onto Cu nanoflakes to regulate the protonation of key intermediates. The Pd sites with moderate water activation capability are found to enhance the protonation of *CO at the neighboring Cu site to *COH, which is confirmed to be the rate-determining step through kinetic isotope effect studies. The formation of *COH-*CO is therefore promoted. Additionally, the Pd sites would preferentially protonate the C-OH group in *COH-*CO due to the spatial approximability and electronic modulation effects, generating *CCO for the selective formation of acetate. An acetate Faradaic efficiency of 59.5% is achieved at -0.78 V vs reversible hydrogen electrode (RHE), with a maximum partial current density of 286 mA cm-2 at -0.86 V vs RHE. The optimized catalyst also exhibits long-term stability for 500 h at 100 mA cm-2 in a membrane electrode assembly. This work reveals a new promoting mechanism for selective CORR with simultaneous tuning of the structural and electronic properties of the proton-supplying sites.
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All-solid-state batteries (ASSBs) represent a highly promising next-generation energy storage technology owing to their inherently high safety, device reliability, and potential for achieving high energy density in the post-ara of lithium-ion batteries, and therefore extensive searches are ongoing for ideal solid-state electrolytes (SSEs). Though promising, there is still a huge barrier that limits the large-scale applications of ASSBs, where there are a couple of bottleneck technical issues. In this perspective, a novel category of electrolytes known as frameworked electrolytes (FEs) are examined, where the solid frameworks are intentionally designed to contain 3D ionic channels at sub-nano scales, rendering them macroscopically solid. The distinctive structural design of FEs gives rise to not only high ionic conductivity but also desirable interfaces with electrode solids. This is achieved through the presence of sub-nano channels within the framework, which exhibit significantly different ion diffusion behavior due to the confinement effect. This perspective offers a compelling insight into the potential of FEs in the pursuit of ASSBs, where FEs offer an exciting opportunity to overcome the limitations of traditional solid-state electrolytes and propel the development of ASSBs as the holy grail of energy storage technology.
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In multi-season clinical trials with a randomize-once strategy, patients enrolled from previous seasons who stay alive and remain in the study will be treated according to the initial randomization in subsequent seasons. To address the potentially selective attrition from earlier seasons for the non-randomized cohorts, we develop an inverse probability of treatment weighting method using season-specific propensity scores to produce unbiased estimates of survival functions or hazard ratios. Bootstrap variance estimators are used to account for the randomness in the estimated weights and the potential correlations in repeated events within each patient from season to season. Simulation studies show that the weighting procedure and bootstrap variance estimator provide unbiased estimates and valid inferences in Kaplan-Meier estimates and Cox proportional hazard models. Finally, data from the INVESTED trial are analyzed to illustrate the proposed method.
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Modelos Estadísticos , Humanos , Modelos de Riesgos Proporcionales , Simulación por Computador , Puntaje de Propensión , Estimación de Kaplan-MeierRESUMEN
Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
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Pared Celular , Hongos , Bacterias , Pared Celular/química , Espectroscopía de Resonancia Magnética , Resonancia Magnética Nuclear Biomolecular , PlantasRESUMEN
The restricted mean time in favor (RMT-IF) summarizes the treatment effect on a hierarchical composite endpoint with mortality at the top. Its crude decomposition into "stage-wise effects," i.e., the net average time gained by the treatment prior to each component event, does not reveal the patient state in which the extra time is spent. To obtain this information, we break each stage-wise effect into subcomponents according to the specific state to which the reference condition is improved. After re-expressing the subcomponents as functionals of the marginal survival functions of outcome events, we estimate them conveniently by plugging in the Kaplan -- Meier estimators. Their robust variance matrices allow us to construct joint tests on the decomposed units, which are particularly powerful against component-wise differential treatment effects. By reanalyzing a cancer trial and a cardiovascular trial, we acquire new insights into the quality and composition of the extra survival times, as well as the extra time with fewer hospitalizations, gained by the treatment in question. The proposed methods are implemented in the rmt package freely available on the Comprehensive R Archive Network (CRAN).
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BACKGROUND: Epidermal growth factor receptor (EGFR) fusions are rare but potentially actionable oncogenic drivers across multiple solid tumors. However, the distribution and molecular characteristics of EGFR fusions in Chinese patients with solid malignancies have not been explored. METHODS: Panel-based next-generation sequencing (NGS) data of 35,023 patients with various types of solid tumors was collected and analyzed from the Simcere Diagnostics (Nanjing, China) database. A 9563-patient cohort was derived from The Cancer Genome Atlas (TCGA) to explore the relationship between EGFR fusion status and overall survival (OS). RESULTS: In this study, prevalence of functional EGFR fusions was 0.303% (106/35,023) in total across solid tumors, which occur more commonly in gastroesophageal junction cancer (1/61, 1.613%), followed by medulloblastoma (1/66, 1.515%) and glioma (33/2409, 1.370%). Analysis showed a prevalence for fusion partners in different tumor types. The top 3 co-mutant genes with EGFR fusion were TP53 (mutation frequency, MF: 65%), BRCA2 (MF: 43%), and ALK (MF: 41%). Furthermore, patients in the EGFR fusion group had a significantly shorter OS than those in the non-EGFR fusion group (p < 0.0001) in the TCGA cohort, suggesting that EGFR fusion might be a high-risk factor for poor prognosis. CONCLUSIONS: Our study is the first retrospective analysis of EGFR fusions in a large-scale solid tumor population, which may provide a reference for future EGFR-TKI clinical trials with EGFR fusions.
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Receptores ErbB , Secuenciación de Nucleótidos de Alto Rendimiento , Neoplasias , Proteínas de Fusión Oncogénica , Humanos , Receptores ErbB/genética , Masculino , Femenino , Proteínas de Fusión Oncogénica/genética , Pronóstico , Tasa de Supervivencia , Persona de Mediana Edad , Neoplasias/genética , Neoplasias/patología , Adulto , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , China/epidemiología , Biomarcadores de Tumor/genética , Estudios de Seguimiento , Proteína BRCA2/genética , Proteína p53 Supresora de Tumor/genética , Quinasa de Linfoma Anaplásico/genética , Anciano , Adulto Joven , Mutación , Adolescente , Estudios Retrospectivos , Pueblos del Este de AsiaRESUMEN
Solid-state nuclear magnetic resonance (ssNMR) measurements of intact cell walls and cellular samples often generate spectra that are difficult to interpret due to the presence of many coexisting glycans and the structural polymorphism observed in native conditions. To overcome this analytical challenge, we present a statistical approach for analyzing carbohydrate signals using high-resolution ssNMR data indexed in a carbohydrate database. We generate simulated spectra to demonstrate the chemical shift dispersion and compare this with experimental data to facilitate the identification of important fungal and plant polysaccharides, such as chitin and glucans in fungi and cellulose, hemicellulose, and pectic polymers in plants. We also demonstrate that chemically distinct carbohydrates from different organisms may produce almost identical signals, highlighting the need for high-resolution spectra and validation of resonance assignments. Our study provides a means to differentiate the characteristic signals of major carbohydrates and allows us to summarize currently undetected polysaccharides in plants and fungi, which may inspire future investigations.
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Celulosa , Polisacáridos , Polisacáridos/análisis , Polisacáridos/química , Espectroscopía de Resonancia Magnética , Celulosa/análisis , Celulosa/química , Pectinas/análisis , Pectinas/química , Imagen por Resonancia Magnética , Pared Celular/químicaRESUMEN
BACKGROUND: Total flavonoids of Rhizoma drynariae (TFRD) is broadly used in the treatment of orthopedic diseases. Nevertheless, the effects and underlying mechanism of TFRD on tendon-bone healing after anterior cruciate ligament reconstruction (ACLR) remain unclear. METHODS: The ACLR mouse model was established. Hematoxylin and Eosin (HE) staining was used for histological analysis of tendon-bone healing. Western blot was utilized to detect the levels of osteogenic related factors (ALP, OCN, RUNX2). The viability and alkaline phosphatase (ALP) activity of bone mesenchymal stem cells (BMSCs) were determined by Cell Counting Kit-8 (CCK-8) and ALP assays. The interaction of estrogen related receptor alpha (ESRRA), estrogen related receptor beta (ESRRB), and golgi-localized γ-ear containing ADP ribosylation factor-binding protein 1 (Gga1) was detected by luciferase reporter assays. The levels of important proteins on the TGF-ß/MAPK pathway were measured by western blot. RESULTS: TFRD improved tendon-bone healing, restored biomechanics of ACLR mice and activated the TGF-ß/MAPK pathway. TFRD treatment also enhanced the viability and osteogenic differentiation of BMSCs in vitro. Then, we demonstrated that TFRD targeted ESRRA and ESRRB to transcriptionally activate Gga1 expression. Knockdown of ESRRA, ESRRB, or Gga1 suppressed the viability and osteogenic differentiation of TFRD-induced BMSCs, which was revealed to be restored by Gga1 overexpression. The overexpression of ESRRA, ESRRB, or Gga1 was demonstrated to promote the BMSC viability and osteogenic differentiation. TGF-ß1 treatment can reverse the impact of Gga1 inhibition on osteogenic differentiation in TFRD-induced BMSCs. CONCLUSION: TFRD improves tendon-bone healing in ACLR mouse models and facilitates the osteogenic differentiation of BMSCs through the ERR1/2-Gga1-TGF-ß/MAPK pathway, which might deepen our understanding of the underlying mechanism of TFRD in tendon-bone healing.
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Reconstrucción del Ligamento Cruzado Anterior , Células Madre Mesenquimatosas , Polypodiaceae , Ratones , Animales , Factor de Crecimiento Transformador beta/metabolismo , Osteogénesis , Polypodiaceae/metabolismo , Diferenciación Celular , Células Madre Mesenquimatosas/metabolismo , Tendones/metabolismo , Células CultivadasRESUMEN
Hydrogen is an essential energy carrier which will address the challenges posed by the energy crisis and climate change. Photoelectrochemical water splitting (PEC) is an important method for producing solar-powered hydrogen. The PEC tandem configuration harnesses sunlight as the exclusive energy source to drive both the hydrogen (HER) and oxygen evolution reactions (OER), simultaneously. Therefore, PEC tandem cells have been developed and gained tremendous interest in recent decades. This review describes the current status of the development of tandem cells for unbiased photoelectrochemical water splitting. The basic principles and prerequisites for constructing PEC tandem cells are introduced first. We then review various single photoelectrodes for use in water reduction or oxidation, and highlight the current state-of-the-art discoveries. Second, a close look into recent developments of PEC tandem cells in water splitting is provided. Finally, a perspective on the key challenges and prospects for the development of tandem cells for unbiased PEC water splitting are given.
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Copper (Cu) can efficiently catalyze the electrochemical CO2 reduction reaction (CO2RR) to produce value-added fuels and chemicals, among which methane (CH4) has drawn attention due to its high mass energy density. However, the linear scaling relationship between the adsorption energies of *CO and *CHxO on Cu restricts the selectivity toward CH4. Alloying a secondary metal in Cu provides a new freedom to break the linear scaling relationship, thus regulating the product distribution. This paper describes a controllable electrodeposition approach to alloying Cu with oxophilic metal (M) to steer the reaction pathway toward CH4. The optimized La5Cu95 electrocatalyst exhibits a CH4 Faradaic efficiency of 64.5%, with the partial current density of 193.5 mA cm-2. The introduction of oxophilic La could lower the energy barrier for *CO hydrogenation to *CHxO by strengthening the M-O bond, which would also promote the breakage of the C-O bond in *CH3O for the formation of CH4. This work provides a new avenue for the design of Cu-based electrocatalysts to achieve high selectivity in CO2RR through the modulation of the adsorption behaviors of key intermediates.
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BACKGROUND: The family with sequence similarity 20-member C (FAM20C) kinase, a Golgi casein kinase, which is responsible for phosphorylating the majority of the extracellular phosphoproteins within S-x-E/pS motifs, and is fundamentally associated with multiple biological processes to maintain cell proliferation, biomineralization, migration, adhesion, and phosphate homeostasis. In dissecting how FAM20C regulates downstream molecules and potential mechanisms, however, there are multiple target molecules of FAM20C, particularly many phenomena remain elusive, such as changes in cell-autonomous behaviors, incompatibility in genotypes and phenotypes, and others. METHODS: Here, assay for transposase-accessible chromatin using sequencing (ATAC-seq), RNA sequencing (RNA-seq), proteomics, and phosphoproteomics were performed in Fam20c-dificient osteoblasts and to facilitate an integrated analysis and determine the impact of chromatin accessibility, genomic expression, protein alterations, signaling pathway, and post translational modifcations. RESULTS: By combining ATAC-seq and RNA-seq, we identified TCF4 and Wnt signaling pathway as the key regulators in Fam20c-dificient cells. Further, we showed Calpastatin/Calpain proteolysis system as a novel target axis for FAM20C to regulate cell migration and F-actin cytoskeleton by integrated analysis of proteomics and phosphoproteomics. Furthermore, Calpastatin/Calpain proteolysis system could negatively regulate the Wnt signaling pathway. CONCLUSION: These observations implied that Fam20c knockout osteoblasts would cause cell homeostatic imbalance, involving changes in multiple signaling pathways in the conduction system.
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Calpaína , Proteínas de la Matriz Extracelular , Proteínas de la Matriz Extracelular/genética , Proteolisis , Calpaína/metabolismo , Movimiento Celular , HomeostasisRESUMEN
Pectins are abundant in the cell walls of dicotyledonous plants, but how they interact with other wall polymers and influence wall integrity and cell growth has remained mysterious. Here, we verified that QUASIMODO2 (QUA2) is a pectin methyltransferase and determined that QUA2 is required for normal pectin biosynthesis. To gain further insight into how pectin affects wall assembly and integrity maintenance, we investigated cellulose biosynthesis, cellulose organization, cortical microtubules, and wall integrity signaling in two mutant alleles of Arabidopsis (Arabidopsis thaliana) QUA2, qua2 and tsd2 In both mutants, crystalline cellulose content is reduced, cellulose synthase particles move more slowly, and cellulose organization is aberrant. NMR analysis shows higher mobility of cellulose and matrix polysaccharides in the mutants. Microtubules in mutant hypocotyls have aberrant organization and depolymerize more readily upon treatment with oryzalin or external force. The expression of genes related to wall integrity, wall biosynthesis, and microtubule stability is dysregulated in both mutants. These data provide insights into how homogalacturonan is methylesterified upon its synthesis, the mechanisms by which pectin functionally interacts with cellulose, and how these interactions are translated into intracellular regulation to maintain the structural integrity of the cell wall during plant growth and development.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/citología , Celulosa/biosíntesis , Metiltransferasas/metabolismo , Mutación , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Adhesión Celular/genética , Pared Celular/genética , Celulosa/genética , Dinitrobencenos/farmacología , Regulación de la Expresión Génica de las Plantas , Hipocótilo/citología , Hipocótilo/genética , Hipocótilo/crecimiento & desarrollo , Metiltransferasas/genética , Microtúbulos/metabolismo , Pectinas/biosíntesis , Pectinas/genética , Pectinas/metabolismo , Células Vegetales/efectos de los fármacos , Células Vegetales/metabolismo , Plantas Modificadas Genéticamente , Sulfanilamidas/farmacología , Ácidos Urónicos/metabolismoRESUMEN
BACKGROUND: The tumor microenvironment contains chemokines that play a crucial role in various processes, such as tumorigenesis, inflammation, and therapy resistance, in different types of cancer. CXCL5 is a significant chemokine that has been shown to promote tumor proliferation, invasion, angiogenesis, and therapy resistance when overexpressed in various types of cancer. This research aims to investigate the impact of CXCL5 on the biological functions of glioblastoma (GBM). METHODS: The TCGA GBM and GEO databases were utilized to perform transcriptome microarray analysis and oncogenic signaling pathway analysis of CXCL5 in GBM. Validation of CXCL5 expression was performed using RT-qPCR and Western Blot. The impact of CXCL5 on cell proliferation, tumorigenesis, and angiogenesis in GBM was assessed through various methods, including cell proliferation assay, cloning assay, intracranial xenograft tumor models, and tube formation assay. Clinical prognosis was evaluated in 59 samples of gliomas with varying degrees of malignancy (grades 2, 3, and 4) and the TCGA GBM database, based on CXCL5 expression levels. The activities of the JAK-STAT and NF-κB signaling pathways were detected using Western Blot. RESULTS: The expression of CXCL5 was highly enriched in GBM. Moreover, the inhibition of CXCL5 showed a significant efficacy in suppressing cellular proliferation and angiogenesis, resulting in extended survival rates in xenograft mouse models in comparison to the control group. Notably, pretreatment with dapsone exhibited a reversal of the impact of CXCL5 on the formation of colonies and tubes in GBM cells. Elevated expression of CXCL5 was correlated with poor outcomes in GBM patients. Furthermore, the overexpression of CXCL5 has been associated with the activation of JAK-STAT and NF-κB signaling pathways. CONCLUSIONS: CXCL5 plays an important role in tumorigenesis and angiogenesis, indicating the potential for novel therapies targeting CXCL5 in GBM.
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Neoplasias Encefálicas , Glioblastoma , Humanos , Animales , Ratones , FN-kappa B/metabolismo , Glioblastoma/metabolismo , Transducción de Señal , Carcinogénesis/genética , Transformación Celular Neoplásica , Neoplasias Encefálicas/metabolismo , Línea Celular Tumoral , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Microambiente Tumoral , Quimiocina CXCL5/genética , Quimiocina CXCL5/metabolismoRESUMEN
Construction of a "net-zero-emission" system through CO2 hydrogenation to methanol with solar energy is an eco-friendly way to mitigate the greenhouse effect. Traditional CO2 hydrogenation demands centralized mass production for cost reduction with mass water electrolysis for hydrogen supply. To achieve continuous reaction with intermittent and fluctuating flow of H2 on a small-scale for distributed application scenarios, modulating the catalyst interface environment and chemical adsorption capacity to adapt fluctuating reaction conditions is highly desired. This paper describes a distributed clean CO2 utilization system in which the surface structure of catalysts is carefully regulated. The Ni catalyst with unsaturated electrons loaded on In2 O3 can reduce the dissociation energy of H2 to overcome the slow response of intermittent H2 supply, exhibiting a faster response (12â min) than bare oxide catalysts (42â min). Moreover, the introduction of Ni enhances the sensitivity of the catalyst to hydrogen, yielding a Ni/In2 O3 catalyst with a good performance at lower H2 concentrations with a 15â times adaptability for wider hydrogen fluctuation range than In2 O3 , greatly reducing the negative impact of unstable H2 supplies derived from renewable energies.
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Acetylation, a prevalent modification of cell-wall polymers, is a tightly controlled regulatory process that orchestrates plant growth and environmental adaptation. However, due to limited characterization of the enzymes involved, it is unclear how plants establish and dynamically regulate the acetylation pattern in response to growth requirements. In this study, we identified a rice (Oryza sativa) GDSL esterase that deacetylates the side chain of the major rice hemicellulose, arabinoxylan. Acetyl esterases involved in arabinoxylan modification were screened using enzymatic assays combined with mass spectrometry analysis. One candidate, DEACETYLASE ON ARABINOSYL SIDECHAIN OF XYLAN1 (DARX1), is specific for arabinosyl residues. Disruption of DARX1 via Tos17 insertion and CRISPR/Cas9 approaches resulted in the accumulation of acetates on the xylan arabinosyl side chains. Recombinant DARX1 abolished the excess acetyl groups on arabinoxylan-derived oligosaccharides of the darx1 mutants in vitro. Moreover, DARX1 is localized to the Golgi apparatus. Two-dimensional 13C-13C correlation spectroscopy and atomic force microscopy further revealed that the abnormal acetylation pattern observed in darx1 interrupts arabinoxylan conformation and cellulose microfibril orientation, resulting in compromised secondary wall patterning and reduced mechanical strength. This study provides insight into the mechanism controlling the acetylation pattern on arabinoxylan side chains and suggests a strategy to breed robust elite crops.