Constructing Synergistic Triazine and Acetylene Cores in Fully Conjugated Covalent Organic Frameworks for Cascade Photocatalytic H2O2 Production

Covalent organic frameworks (COFs) are an ideal template for photocatalytic H2O2 synthesis because of the tunable chemical structures and semiconductor properties. However, the photoactivity for COFs is still under-improved due to the inefficient intrinsic charge generation, fast recombination of photogenerated charges, and limited electron transport along the frameworks. Herein, spatially separated and synergistic triazine and acetylene units are first integrated into COFs (EBA-COF and BTEA-COF) for photocatalytic H2O2 production. The spatial separation of triazine and acetylene cores leads to efficient charge separation and suppressed charge recombination, and C═C linkage facilitates electrons transport over the skeletons. Both experimental and computational results suggested that triazine and acetylene units synergistically promote H2O2 synthesis in a two-electron pathway. The EBA-COF showed an attractive activity with a H2O2 production rate of 1830 μmol h-1 gcat-1, superior to that of most other COF-based catalysts. This study provides a method for designing photocatalysts with synergistic photocatalytic active sites based on vinylene-linked COFs

chenxiating/urban_green_gray_model: Initial release v1.0

This release contains the simulation scripts used for manuscript "Integrating the spatial configurations of green and gray infrastructure in urban stormwater networks" in Water Resources Research

Coupled multiscale-modeling of microwave-heating-induced fracturing in shales

Microwave heating may be used to stimulate fracture formation and the release of hydrocarbons in gas shales. Although extensively studied experimentally and numerically, the microscopic observations are not fully explained in current work where the heating, at sample-scale, and fracturing, at the mineral-scale, are represented independently. Furthermore, the geometry, structure and mechanical interaction of different minerals are not fully considered in current approaches. We present a novel simulation approach to investigate the coupled electromagnetic-heating-stress-damage process. Microwave heating is simulated at sample-scale and the resulting stress-damage response is examined at micro-scale where minerals with contrasting thermo-mechanical characteristics are stacked as lamellae, instead of nested internally as in previous representations. A three-stage temperature evolution profile is observed in the shale samples – although some stages may be absent in other rocks. The mathematical model accounts for the three modes of stress generated between minerals: horizontal stress (σh) (tensile stress parallel to the grain-grain interface) and the normal stress(σn) (tensile stress normal to the grain-grain interface) applied on the minerals, and the shear stress (τ) applied on the interface between different minerals. The minerals comprising the shale matrix are categorized into three types – ‘high’, ‘intermediate’ and ‘low’ – conversion efficiency based on their susceptibility to thermal stressing from microwave irradiation. Shear damage and intergranular fracture usually occurs for minerals with high dielectric permittivity. Transgranular fracture may feature both in high permittivity minerals, due to the larger induced horizontal stress (σh), and in low permittivity minerals - due to high volume fraction and larger size. The simulation approach is a powerful way to link the macro-scale characterization and heating to micro-mechanisms of rock failure. Also this work provides mineral classification and criteria to define a priori evaluation of the effectiveness of microwave treatment of shales and other mineral aggregates

A heptazine-based polymer photocatalyst with donor-acceptor configuration to promote exciton dissociation and charge separation

Polymeric carbon nitride (PCN) is an emerging class of polymer semiconductor photocatalysts, but bulk PCN typically suffers from low visible-light-harvesting ability, high activation energy, and rapid charge recombination. In this context, using the same core building block, a donor-acceptor (D-A) type heptazine-based polymer, namely BPCN, was proposed via Friedel-Crafts arylation reaction to tackle these issues. Comparatively, the affording BPCN features extended light absorption, reduced activation energy, and suppressed charge recombination, triggered by the electron push-pull interactions as a consequence of the D-A configuration. BPCN is elucidated to be an effective heterogeneous photocatalyst for aerobic organic transformations and a wide range of substrate scopes and reactions were realized. Besides, BPCN also showed an advantage in mediating the photocatalytic water oxidation reaction, achieving a nearly 10-fold oxygen evolution reaction (OER) rate over PCN. These findings demonstrate the great potential of the rational design of heptazine-based polymers with D-A configurations for artificial photosynthesis

Association between Chinese Dietary Guidelines Compliance Index for Pregnant Women and Risks of Pregnancy Complications in the Tongji Maternal and Child Health Cohort

Background: Compliance with dietary guidelines among pregnant women can positively influence not only their own health but also the health of their babies. Measuring the compliance requires professional skills in nutrition and dietary counseling. In China, few simple and effective techniques assess dietary quality among pregnant women, especially in rural areas. We aimed to establish a new simple and effective assessment technique, the “Chinese Dietary Guidelines Compliance Index for Pregnant Women (CDGCI-PW)” and assess the association between maternal dietary compliance and risks of pregnancy complications. Methods: The CDGCI-PW consists of 13 main components which were based on the 2016 edition of the Chinese dietary guidelines for pregnant women. Each component was assigned a different score range, and the overall score ranged from 0 to 100 points. The Tongji Maternal and Child Health Cohort study (from September 2013 to May 2016) was a prospective cohort study designed to examine maternal dietary and lifestyle effects on the health of pregnant women and their offspring. The maternal diet during the second trimester was compared with the corresponding recommended intake of the Chinese balanced dietary pagoda for pregnant women to verify their compliance with dietary guidelines. The association between maternal dietary quality and risks of pregnancy complications was estimated by regression analysis. Receiver operating characteristic (ROC) curves were constructed to identify the optimal cut-off values of CDGCI-PW for gestational hypertension and gestational diabetes mellitus (GDM). Results: Among the 2708 pregnant women, 1489 were eventually followed up. The mean CDGCI-PW score was 74.1 (standard deviation (SD) 7.5) in the second trimester. The majority of foods showed the following trend: the higher the CDGCI-PW score, the higher the proportion of pregnant women who reported food intake within the recommended range. Moreover, a higher maternal CDGCI-PW score was significantly associated with lower risks of gestational hypertension [odds ratio (OR) (95% confidence interval [(CI): 0.30 (0.20, 0.37)] and GDM [OR (95% CI): 0.38 (0.31, 0.48)]. The optimal CDGCI-PW cut-off value for gestational hypertension was ≥68.5 (sensitivity 82%; specificity: 61%; area under the ROC curve, AUC = 0.743), and the optimal CDGCI-PW cut-off score for GDM was ≥75.5 (sensitivity 43%; specificity: 81%; area under the ROC curve, AUC = 0.714). Conclusions: The CDGCI-PW is a simple and useful technique that assesses maternal diet quality during pregnancy, while adherence to the CDGCI-PW is associated with a lower risk of gestational hypertension and GDM

A rare missense variant in TCF7L2 associates with colorectal cancer risk by interacting with a GWas-identified regulatory variant in the MYC enhancer

Genome-wide association studies (GWAS) of colorectal cancer have identified several common susceptible variants in gene regulatory regions. However, low-frequency or rare coding risk variants have not been systematically investigated in patients with colorectal cancer from Chinese populations. In this study, we performed an exome-wide association analysis with 1,062 patients with colorectal cancer and 2,184 controls from a Chinese population. Promising associations were further replicated in two replication sets: replication stage I with 2,478 cases and 3,880 controls, and replication stage II with 3,761 cases and 4,058 controls. We identified two variants significantly associated with colorectal cancer risk: a novel rare missense variant in TCF7L2 [rs138649767, OR ¼ 2.08, 95% confidence interval (CI): 1.69–2.57, P ¼ 5.66 1012] and a previous European GWAS-identified 30-UTR variant in ATF1 (rs11169571, OR ¼ 1.18, 95% CI: 1.13–1.24, P ¼ 1.65 1012). We found a significant interaction between the TCF7L2 missense variant rs138649767 and a previous GWAS-identified regulatory variant rs6983267 in the MYC enhancer (Pinteraction ¼ 0.0002). Functional analysis of this variant revealed that TCF7L2 with rs138649767-A allele harbored the ability to activate the MYC enhancer with rs6983267-G allele and enhance colorectal cancer cell proliferation. In addition, the ATF1 rs11169571 variant significantly correlated with ATF1 expression by affecting hsa-miR-1283 and hsa-miR-520d-5p binding. Further ChIP-seq and gene coexpression analyses showed that oncogenes NRAS and BRAF were activated by ATF1 in colorectal cancer. These results widen our understanding of the molecular basis of colorectal cancer risk and provide insight into pathways that might be targeted to prevent colorectal cancer