Visible-light-mediated metal-free regioselective oxidative C-C bond cleavage of lignin dimers to aromatic acids.

The upgrading of lignin is a sustainable and promising pathway for fossil-based aromatic compounds but always faces low selectivity. Herein, a metal-free photocatalyst, 2,4,6-triphenylpyrylium tetrafluoroborate (TPP), was illustrated to remarkably facilitate the regioselective oxidative C-C bond cleavage of β-1 and β-O-4 lignin alcohol/ketone models into aromatic acids (92-99% yields) under visible-light irradiation at room temperature without any additive/co-catalyst, which was enabled by the synergistic effect of C-H⋯C(TPP) interaction and·˙O/O species. The synergy of the catalyst-substrate interaction and active species offers a reference for the enhancive and selective transformation of polymeric biomass and complex molecules.

Trajectories of antepartum depressive symptoms and birthweight: a multicenter and prospective cohort study.

Background: Antepartum depression is a prevalent unhealthy mental health problem worldwide, particularly in low-income countries. It is a major contributor to adverse birth outcomes. Previous studies linking antepartum depression to birthweight have yielded conflicting results, which may be the reason that the depressive symptoms were only measured once during pregnancy.

Trajectories of depressive symptoms during pregnancy and risk of premature birth: A multicenter and prospective cohort study.

Previous studies only assessed the association between depressive symptoms and risk of preterm birth (PTB) at a time-point during pregnancy, resulting in inconsistent or contradictory results. Therefore, we aimed to explore the associations between the trajectories of depressive symptoms during pregnancy and risk of PTB. In total, 7732 pregnant women were included in 24 hospitals from 15 provinces of China.

Pre-pregnancy body mass index and risk of maternal or infant complications with gestational diabetes mellitus as a mediator: A multicenter, longitudinal cohort study in China.

Aims: We explored the complex relationships between pre-pregnancy body mass index (pBMI) and maternal or infant complications and the mediating role of gestational diabetes mellitus (GDM) in these relationships.

Methods: Pregnant women from 24 hospitals in 15 different provinces of China were enrolled in 2017 and followed through 2018. Propensity score-based inverse probability of treatment weighting, logistic regression, restricted cubic spline models, and causal mediation analysis were utilized.

activation of COOH-functionalized ZIF-90-enabled reductive CO-formylation.

A heterogeneous ZIF-90-based catalyst functionalized with COOH and with a porous structure was facilely prepared for efficient CO adsorption and activation to undergo reductive -formylation with a wide range of amines (15 examples) to furnish -formamides (78-94% yields). The -COO species generated by an interaction with amine acts as a key species for activating hydrosilane to capture CO, and remarkably facilitates a cascade C-N coupling and hydrogenation process. Our findings show a facile strategy for the rational construction of robust active sites for reductive CO valorization.

Oxidative C-C bond cleavage of lignin electrocatalysis.

Lignin, which is an important component of biomass in nature and is constantly produced in industry, becomes potential raw material for sustainable production of fine chemicals and biofuels. Electrocatalysis has been extensively involved in the activation of simple molecules and cleavage-recasting of complex scaffolds in an elegant environment. As such, electrocatalytic cleavage of C-C(O) in -O-4 model molecules of lignin to value-added chemicals has received much attention in recent years.

Development of Sustainable Catalytic Pathways for Furan Derivatives.

Biomass, the only globally available, renewable feedstock of organic carbon, is considered a viable alternative to fossil fuels. It can be efficiently utilized to produce various building blocks in accordance with green and sustainable chemistry principles. In this review, recent progress, such as the transformation of carbohydrates (C5 or C6 sugar, inulin, and cellulose) and their derivatives (furfural, hydroxymethylfurfural) into significant platform chemicals over polyoxometalates, zeolites, non-noble metals, and ionic liquids in single or multiphase, is evaluated.

Comparison of detection strategies for screening and confirming congenital cytomegalovirus infection in newborns in a highly seroprevalent population: a mother-child cohort study.

Background: Universal screening of congenital cytomegalovirus (cCMV) infection is important for monitoring and intervention during critical stages of speech and language development. This study aimed to explore the optimal detection strategy for cCMV infection screening.

Methods: Serum samples from pregnant women and saliva and urine samples from their newborns were collected for the anti-CMV IgG and CMV DNA PCR tests, respectively.

Advances in Pretreatment of Straw Biomass for Sugar Production.

Straw biomass is an inexpensive, sustainable, and abundant renewable feedstock for the production of valuable chemicals and biofuels, which can surmount the main drawbacks such as greenhouse gas emission and environmental pollution, aroused from the consumption of fossil fuels. It is rich in organic content but is not sufficient for extensive applications because of its natural recalcitrance. Therefore, suitable pretreatment is a prerequisite for the efficient production of fermentable sugars by enzymatic hydrolysis.

Cohort profile: the Chinese Pregnant Women Cohort Study and Offspring Follow-up (CPWCSaOF).

Purpose: A multicentre prospective cohort study, known as the Chinese Pregnant Women Cohort Study (CPWCS), was established in 2017 to collect exposure data during pregnancy (except environmental exposure) and analyse the relationship between lifestyle during pregnancy and obstetric outcomes. Data about mothers and their children's life and health as well as children's laboratory testing will be collected during the offspring follow-up of CPWCS, which will enable us to further investigate the longitudinal relationship between exposure in different periods (during pregnancy and childhood) and children's development.

Participants: 9193 pregnant women in 24 hospitals in China who were in their first trimester (5-13 weeks gestational age) from 25 July 2017 to 26 November 2018 were included in CPWCS by convenience sampling.

Current Approaches to Alkyl Levulinates Efficient Valorization of Biomass Derivatives.

Biomass is a potential non-food, carbon-neutral, and abundant resource, which can be used as an alternative to fossil fuels during the sustainable preparation of various platform chemicals. Alkyl levulinates (ALs) have found widespread application as flavorings, plasticizing agents, and fuel additives, as well as synthetic precursors to various building blocks. Several processes have been investigated to transform biomass and its derivatives into ALs, which mainly include: (i) direct esterification of levulinic acid (LA) with alkyl alcohols and (ii) alcoholysis reactions of renewable biomass feedstocks and their derivatives, including furfuryl alcohol (FAL), chloromethyl furfural (CMF), and saccharides.

Heteropoly Acid-Based Catalysts for Hydrolytic Depolymerization of Cellulosic Biomass.

Cellulose is the most abundant source of biomass, which can be converted into monosaccharide or other chemical platform molecules for the sustainable production of chemicals and fuels. Acid catalysts can promote hydrolytic degradation of cellulose into valuable platform molecules, which is of great significance in the development of chemicals and biofuels. However, there are still some shortcomings and limitations of the catalysts for the hydrolytic degradation of cellulosic biomass.

Recent advances in liquid hydrosilane-mediated catalytic -formylation of amines with CO.

Carbon dioxide is an ideal raw material for the synthesis of complex organic compounds because of its rich, non-toxic, and good physical properties. It is of great significance to transform CO into valuable fine chemicals and develop a green sustainable cycle of carbon surplus. Based on hydrosilane as a reducing agent, this work summarizes the recent applications of reductive amidation of CO using different catalysts such as organocatalysts, ionic liquids (ILs), salts, transition metal complexes, and solvents.

CO -Enabled Biomass Fractionation/Depolymerization: A Highly Versatile Pre-Step for Downstream Processing.

Lignocellulosic biomass is inevitably subject to fractionation and depolymerization processes for enhanced selectivity toward specific products, in most cases prior to catalytic upgrading of the three main fractions-cellulose, hemicellulose, and lignin. Among the developed pretreatment techniques, CO -assisted biomass processing exhibits some unique advantages such as the lowest critical temperature (31.0 °C) with moderate critical pressure, low cost, nontoxicity, nonflammability, ready availability, and the addition of acidity, alongside easy recovery by pressure release.

A Facile Direct Route to N-(Un)substituted Lactams by Cycloamination of Oxocarboxylic Acids without External Hydrogen.

Lactams are privileged in bioactive natural products and pharmaceutical agents and widely featured in functional materials. This study presents a novel versatile approach to the direct synthesis of lactams from oxocarboxylic acids without catalyst or external hydrogen. The method involves the in situ release of formic acid from formamides induced by water to facilitate efficient cycloamination.

[Studies on flavonoids from Derris eriocarpa].

Derris eriocarpa, a traditional Chinese medicine belonging to the family of Leguminosae, is widely distributed mainly over Yunnan, Guangxi and Guizhou of China. Modern pharmacological researches on this herb showed that it had extensive bioactivities, such as promoting urination, removing dampness and cough and reducing inspissated mucus and other biological activities. The extensive studies on the chemical constituents of this plant have resulted in the isolation of triterpenoids, steroids, fatty acid and others, but the flavone compounds haven't reported before.