ABSTRACT
Electrocatalytic oxidation of organics using water as the oxygen source is a prospective but challenging method to produce high-value-added chemicals; especially, the competitive oxygen evolution reaction (OER) limits its efficiency. Herein, a tandem catalysis strategy based on a single-atom catalyst with Cr atoms atomically dispersed at a CoSe2 support (Cr1 /CoSe2 ) is presented. Thereinto, Co and Cr sites are endowed with a specific function to activate water and styrene respectively, and the competition between the OER and styrene oxidation is turned into mutual benefits via cooperated active sites. Under a potential of 1.6 VAg/AgCl , excellent selectivity of 95% to benzaldehyde and a high conversion rate of styrene at 88% without any exogenous oxidizing reagent are achieved. Isotopic tracing, isotope-labeled in situ Raman spectra, and detailed theoretical calculation further reveal the tandem mechanism, showing that the transfer of *OOH intermediates from the Co to the Cr sites serves as a bridge to link the oxidation of water and styrene. This work develops a new strategy for the co-oxidation of multi-species based on tandem catalysis, providing novel insights for the design of single-atom catalysts.
ABSTRACT
It has been documented that secreted frizzled-related protein 1 (SFRP1) is epigenetically silenced in laryngeal carcinoma. However, the function of SFRP1 in laryngeal carcinoma remains elusive. In this study, we performed gain-of-function studies to determine the roles of SFRP1 in laryngeal carcinoma growth, tumorigenesis, and cisplatin resistance. Laryngeal carcinoma cell lines were treated with 5-aza-2'-deoxycytidine (5-aza-dC) and examined for SFRP1 expression. The effects of overexpression of SFRP1 on cell proliferation, colony formation, apoptosis, tumorigenesis, and cisplatin sensitivity were assessed. It was found that 5-aza-dC exposure significantly induced the expression of SFRP1 in both Hep-2 and SNU899 laryngeal carcinoma cells. Ectopic expression of SFRP1 significantly decreased cell proliferation and colony formation in vitro and retarded xenograft tumor growth in vivo. SFRP1-overexpressing Hep-2 cells displayed a higher percentage of apoptosis and enhancement of caspase-3 cleavage, which was coupled with loss of Δψm and increased release of cytochrome c from the mitochondria to the cytosol. Moreover, SFRP1 overexpression sensitized laryngeal carcinoma cells to cisplatin and decreased intracellular pH values. Mechanistically, SFRP1 inhibited the expression of Na+/H+ exchanger 1 (NHE1) and overexpression of NHE1 reversed the suppressive activity of SFRP1 on laryngeal carcinoma cells. In conclusion, we demonstrate that SFRP1 induces mitochondrial apoptosis and increases cisplatin sensitivity in laryngeal carcinoma cells via downregulation of NHE1. Delivery of SFRP1 may offer therapeutic benefits in the treatment of laryngeal carcinoma.
ABSTRACT
BACKGROUND: Severe acute pancreatitis (SAP) remains a clinical challenge with considerable morbidity and mortality. An early identification of infected pancreatic necrosis (IPN), a life-threatening evolution secondary to SAP, is obliged for a more preferable prognosis. Thus, the present study was conducted to identify the risk factors of IPN secondary to SAP. METHODS: The clinical data of patients with SAP were retrospectively analyzed. Univariate and multivariate logistic regression analyses were sequentially performed to assess the associations between the variables and the development of IPN secondary to SAP. A receiver operating characteristic (ROC) curve was created for each of the qualified independent risk factors. RESULTS: Of the 115 eligible patients, 39 (33.9%) progressed to IPN, and the overall in-hospital mortality was 11.3% (13/115). The early enteral nutrition (EEN) (P=0.0092, OR=0.264), maximum intra-abdominal pressure (IAP) (P=0.0398, OR=1.131) and maximum D-dimer level (P=0.0001, OR=1.006) in the first three consecutive days were independent risk factors associated with IPN secondary to SAP. The area under ROC curve (AUC) was 0.774 for the maximum D-dimer level in the first three consecutive days and the sensitivity was 90% and the specificity was 58% at a cut-off value of 933.5 µg/L; the AUC was 0.831 for the maximum IAP in the first three consecutive days and the sensitivity was 95% and specificity was 58% at a cut-off value of 13.5 mmHg. CONCLUSIONS: The present study suggested that the maximum D-dimer level and/or maximum IAP in the first three consecutive days after admission were risk factors of IPN secondary to SAP; an EEN might be helpful to prevent the progression of IPN secondary to SAP.
