Modulate synthesis of CeMn solid solution using various alcohols for toluene catalytic oxidation: synergistic effect of Ce-Mn and reaction mechanism.

A redox co-precipitation method was employed to synthesize CeMn homogeneous solid solutions, utilizing various alcohols as activating agents. Ethanol effectively orchestrated the precipitation of CeO2 and MnOx, promoting their co-growth. As a result, the CeMn-EA achieved 90 % toluene conversion at 218 â„ƒ (T90 =218 â„ƒ) with a weight hourly space velocity (WHSV) of 48000 ml/(g·h). It also demonstrated high adaptability to increased WHSV, suggesting its potential for industrial-scale applications. The uniform dispersion of Ce and Mn accelerated the coupling between Ce3+/Ce4+ and Mn4+/Mn3+, engineering numerous oxygen vacancies, which enhanced the activation of gas-phase oxygen and the mobility of lattice oxygen. In situ DRIFTS confirmed that toluene oxidation accommodated both Langmuir-Hinshelwood (L-H) and Mars-van Krevelen (MvK) mechanisms, with benzoate identified as a pivotal intermediate. Enhanced oxygen mobility facilitated the cleavage of the benzene ring, which was the rate-determining step. Additionally, the introduction of H2O significantly enhanced the dissociation and adsorption of toluene and facilitated the activation of gas-phase oxygen. At higher temperatures, H2O could further activate lattice oxygen engaging in toluene oxidation. ENVIRONMENTAL IMPLICATION: Volatile organic compounds (VOCs) have emerged as major air pollutants due to the changes in air pollution patterns. They can act as precursors to near-surface ozone and haze. Toluene, a typical VOC, is primarily released from anthropogenic sources and poses significant risks to human health and the environment. Ce-based catalysts have been demonstrated efficiency in toluene oxidation due to their excellent oxygen storage and release properties. This study synthesized CeMn homogeneous solid solutions utilizing various alcohols as activating agents, which possessed abundant oxygen vacancies and optimum oxygen activation capacity to oxidize toluene in time.

Association between lactate dehydrogenase and ventilator-associated pneumonia risk: an analysis of the MIMIC database 2001-2019.

BACKGROUND: Serum lactate dehydrogenase (LDH) is a nonspecific inflammatory biomarker and has been reported to be associated with pneumonia prognosis. This study aimed to evaluate the relationship between LDH levels and ventilator-associated pneumonia (VAP) risk in intensive care unit (ICU) patients. METHODS: This retrospective cohort study used data from the Multiparameter Intelligent Monitoring in Intensive Care database from 2001 to 2019. ICU patients aged ≥ 18 years and receiving mechanical ventilation were included. LDH levels were analyzed as continuous and categorical variables (< 210, 210-279, 279-390, > 390 IU/L), respectively. Restricted cubic spline (RCS) curves and quartiles were used to categorize LDH levels. Logistic regression and linear regression were utilized to assess the relationship of LDH levels with VAP risk and duration of mechanical ventilation, respectively. RESULTS: A total of 9,164 patients were enrolled, of which 646 (7.05%) patients developed VAP. High levels of LDH increased the risk of VAP [odds ratio (OR) = 1.15, 95% confidence interval (CI): 1.06-1.24] and LDH levels were positively correlated with the duration of mechanical ventilation [ß = 4.49, 95%CI: (3.42, 5.56)]. Moreover, patients with LDH levels of 279-390 IU/L (OR = 1.38, 95%CI: 1.08-1.76) and > 390 IU/L (OR = 1.50, 95%CI: 1.18-1.90) had a higher risk of VAP than patients with LDH levels < 210 IU/L. Patients with LDH levels of 279-390 IU/L [ß = 3.84, 95%CI: (0.86, 6.82)] and > 390 IU/L [ß = 11.22, 95%CI: (8.21, 14.22)] (vs. <210 IU/L) had a longer duration of mechanical ventilation. CONCLUSION: Elevated serum LDH levels were related to a higher risk of VAP and longer duration of mechanical ventilation and may be useful for monitoring VAP risk.

Ce-based three-dimensional mesoporous microspheres with Mn homogeneous incorporation for toluene oxidation.

Ce-based three-dimensional (3D) mesoporous microspheres with Mn homogeneous incorporation were synthesized. The CeMn-0.4, characterized by a Ce/Mn molar ratio of 6:4, demonstrated exceptional catalytic activity and stability. The formation of CeMn solid solution strengthened the Ce-Mn interaction, yielding higher concentrations of Ce3+ and Mn4+. Mn4+ initiated toluene preliminary activation owing to its robust oxidative properties, while Ce3+ contributed to oxygen vacancy generation, enhancing the activation of gaseous oxygen and lattice oxygen mobility. Integrating experiments and Density Functional Theory (DFT) calculations elucidated the oxygen reaction mechanisms. A portion of oxygen was converted into surface reactive oxygen species (Oads) that directly oxidized toluene. Additionally, the presence of oxygen vacancies promoted the participation of oxygen in toluene oxidation by converting it into lattice oxygen, which was crucial for the deep oxidation of toluene. Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) indicated the accumulation of benzene-ring intermediates on the catalyst surface hindered continuous toluene oxidation. Thus, the abundant oxygen vacancies in CeMn-0.4 played a pivotal role in sustaining the oxidation process by bolstering the activation of gaseous oxygen and the mobility of lattice oxygen.

Therapeutic effects of human umbilical cord mesenchymal stem cell on sepsis-associated encephalopathy in mice by regulating PI3K/AKT pathway.

Sepsis-associated encephalopathy is a common brain diseases, presenting severe diffuse brain dysfunction. The umbilical cord mesenchymal stem cells have been reported to have protective role for treating diseases, while its role in sepsis-associated encephalopathy remained elusive. This brief report investigated the therapeutic effect of umbilical cord mesenchymal stem cells on sepsis-associated encephalopathy in mice model and uncovering the underlying mechanism. The sepsis-associated encephalopathy mice were injected with 3 mg/kg lipopolysaccharide. An enzyme-linked immunosorbent assay was carried out to determine the production of inflammatory cytokines. Morris water maze test was used to evaluate mice's neurological dysfunction. Cell apoptosis and tissue injury of the cerebral cortex were assessed using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and HE staining. Evans Blue leakage detection was used to examine the blood-brain barrier integrity. The protein levels were determined using Western blot. Results showed that the productions of inflammatory cytokines including interleukin 6 (IL-6), interleukin-1ß (IL-1ß), tumor necrosis factor α (TNF-α), and high mobility group box protein 1 (HMGB1) and activated NF-κB were increased in sepsis-associated encephalopathy mice, which were decreased by umbilical cord mesenchymal stem cells treatment. Besides, umbilical cord mesenchymal stem cells inhibited lipopolysaccharide-induced cell apoptosis and neuron injury of the cerebral cortex in sepsis-associated encephalopathy mice. Moreover, cognitive dysfunction was observed in sepsis-associated encephalopathy mice, which was alleviated by umbilical cord mesenchymal stem cells. Furthermore, umbilical cord mesenchymal stem cells activated PI3K/AKT signaling pathway. In conclusion, umbilical cord mesenchymal stem cells alleviated inflammation, cell apoptosis and neuron injury of the cerebral cortex, and cognitive dysfunction in sepsis-associated encephalopathy animal model in a PI3K/AKT dependent pathway, making them to be a promising therapeutic strategy for treating sepsis-associated encephalopathy.