Core–shell Cu@(CuCo-alloy)/Al2O3 catalysts are obtained via an in situ growth–calcination–reduction process, which exhibit excellent catalytic behavior toward CO hydrogenation to produce higher alcohols.
Abstract:The family of polyoxometalate (POM) intercalated layered double hydroxides (LDHs) composite materials has shown great promise for the design of functional materials with numerous applications. It is known that intercalation of the classical Keggin polyoxometalate (POM) of [PW12O40] 3-(PW12) into layered double hydroxides (LDHs) is very unlikely to take place by conventional ion exchange methods due to spatial and geometrical restrictions. In this paper, such intercalated compound of Mg0.73Al0.22(OH)2 [PW12O40]0.04·0.98H2O (Mg3Al-PW12) has been successfully obtained by adopting a spontaneous flocculation method. The Mg3Al-PW12 has been fully characterized using a wide range of methods (XRD, SEM, TEM, XPS, EDX, XPS, FT-IR, NMR, BET). XRD patterns of Mg3Al-PW12 exhibit no impurity phase usually observed next to the (003) diffraction peak. Subsequent application of the Mg3Al-PW12 as catalyst in Knoevenagel condensation reactions of various aldehydes and ketones with Z-CH2-Z' type substrates (ethylcyanoacetate and malononitrile) at 60 o C in mixed solvents (Vipropanol:Vwater = 2 : 1) demonstrated highly efficient catalytic activity. The synergistic effect between the acidic and basic sites of the Mg3Al-PW12 composite proved to be crucial for the efficiency of the condensation reactions. Additionally, the Mg3Al-PW12 catalysed Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate demonstrated the highest turnover number (TON) of 47980 reported so far.
Background: The adverse pregnancy outcomes caused by teenage pregnancy are major public health problems with significant social impact. While China is the most populous country in the world, and 8.5% of the women aged 10-50 years are adolescent women, we aimed to analyze the adverse maternal and perinatal outcomes of the adolescent pregnancy in Hebei Province, China. Methods: There were 238,598 singleton pregnant women aged 10-34 years from January 1, 2013 to December 31, 2017 in the database of Hebei Province Maternal Near Miss Surveillance System (HBMNMSS). The 238,598 pregnant women were divided into two groups: adolescent group (aged 10-19 years) and adult group (aged 20-34 years). The adolescent group was divided into two subgroups (aged 10-17 years, aged 18-19 years), the adult group was divided into two subgroups (aged 20-24 years, aged 25-34 years). We compared the risk of adverse pregnancy outcomes using univariate and multivariate logistic regression. We also made a stratified analysis of nulliparous and multiparous adolescent pregnancy. Results: Compared with women aged 20-34 years, women aged 10-19 years had lower risk of cesarean delivery [adjusted risk ratio (aRR): 0.75, 95% confidence interval (CI): 0.70-0.80], gestational diabetes mellitus (GDM) (aRR: 0.55, 95%CI: 0.41-0.73). Women aged 10-19 years had higher risk of preterm delivery (aRR: 1.76, 95%CI: 1.54-2.01), small for gestational age (
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