Quest for Zeolite-like Supramolecular Assemblies: Self-Assembly of Metal–Organic Squares via Directed Hydrogen Bonding

Our conceived approach based on the directed assembly of functional metal–organic squares (MOSs), 4-membered ring (4MR) building units, permitted the construction of two novel zeolite-like supramolecular assemblies (ZSAs), namely [Co₄(ImDC)₄(En)₄]⋅9 H₂O⋅1.5 DMF ( ZSA-10 ) and [Co₄(ImDC)₄(En)₄]⋅7 H₂O ( ZSA-11 ) (H₃ImDC=4,5-imidazoledicarboxylic acid, En=ethylenediamine, DMF=N,N-dimethylformamide). The elected MOSs encompass both trans- and cis-coordinated nodes, offering complementary peripheral functional groups for their directed assembly into zeolite-like topologies via supramolecular hydrogen bonding interactions. Distinctly, ZSA-10 possesses the underling MER zeolite topology and is the only pure MER framework material (without any supporting templates) exhibiting permanent porosity up to now. ZSA-11 has the underlying ABW topology together with one type of narrow channel.     

伞形酮对黄嘌呤氧化酶的抑制作用研究

The investigation on inhibition of xanthine oxidase by umbelliferone was carried out using a polyaniline-xanthine oxidase electrode. The experimental results indicated significant inhibition caused by umbelliferone. The apparent Michaelis-Menten constant (K'm) and the maximum rate (im) of the immobilized xanthine oxidase were both affected by umbelliferone. This indicated that umbelliferone acts as a mixed type of inhibitor of xanthine oxidase. The optimal pH of the immobilized enzyme was hardly affected by umbelliferone; The response current increases with increasing potential in the potential range 0.55~0.68V.     

A simple and fast LC–MS/MS method for the simultaneous determination of tenofovir alafenamide and tenofovir in human plasma

A simple and fast liquid chromatography–tandem mass spectrometry method was established and validated for the simultaneous determination of tenofovir alafenamide (TAF) and tenofovir (TNF) in human plasma. A simple protein precipitation procedure was employed to extract analytes from plasma. Chromatographic separation was performed on an Eclipse Plus C₁₈ column utilizing a fast gradient elution starting with 2% of 2 mM ammonium acetate–formic acid (100/0.1, v/v) followed by increasing the percentage of acetonitrile. Detection was performed on a tandem mass spectrometer equipped with an electrospray ionization source operated in the positive ionization mode, using the transitions m/z 477.2 → m/z 346.1 for TAF and m/z 288.1 → m/z 176.1 for TNF. TAF-d₅ and TNF-d₇ were used as the internal standard of TAF and TNF, respectively. The method was validated in the concentration ranges 1.25–500 ng/mlfor TAF and 0.300–15.0 ng/ml for TNF with acceptable accuracy and precision.     

Comprehensive profiles and diagnostic value of menopausal-specific gut microbiota in premenopausal breast cancer

In Western countries, breast cancer tends to occur in older postmenopausal women. However, in Asian countries, the proportion of younger premenopausal breast cancer patients is increasing. Increasing evidence suggests that the gut microbiota plays a critical role in breast cancer. However, studies on the gut microbiota in the context of breast cancer have mainly focused on postmenopausal breast cancer. Little is known about the gut microbiota in the context of premenopausal breast cancer. This study aimed to comprehensively explore the gut microbial profiles, diagnostic value, and functional pathways in premenopausal breast cancer patients. Here, we analyzed 267 breast cancer patients with different menopausal statuses and age-matched female controls. The α-diversity was significantly reduced in premenopausal breast cancer patients, and the β-diversity differed significantly between breast cancer patients and controls. By performing multiple analyses and classification, 14 microbial markers were identified in the different menopausal statuses of breast cancer. Bacteroides fragilis was specifically found in young women of premenopausal statuses and Klebsiella pneumoniae in older women of postmenopausal statuses. In addition, menopausal-specific microbial markers could exhibit excellent discriminatory ability in distinguishing breast cancer patients from controls. Finally, the functional pathways differed between breast cancer patients and controls. Our findings provide the first evidence that the gut microbiota in premenopausal breast cancer patients differs from that in postmenopausal breast cancer patients and shed light on menopausal-specific microbial markers for diagnosis and investigation, ultimately providing a noninvasive approach for breast cancer detection and a novel strategy for preventing premenopausal breast cancer.Subject terms: Bacterial genetics, Breast cancer     

Analysis of Serum Metabolomics in Rats with Osteoarthritis by Mass Spectrometry

Osteoarthritis is a common multifactorial chronic disease that occurs in articular cartilage, subchondral bone, and periarticular tissue. The pathogenesis of OA is still unclear. To investigate the differences in serum metabolites between OA and the control group, liquid chromatography/mass spectrometry (LC/MS)-based metabolomics was used. To reveal the pathogenesis of OA, 12 SD male rats were randomly divided into control and OA groups using collagenase to induce OA for modeling, and serum was collected 7 days after modeling for testing. The OA group was distinguished from the control group by principal component analysis and orthogonal partial least squares-discriminant analysis, and six biomarkers were finally identified. These biomarkers were metabolized through tryptophan metabolism, glutamate metabolism, nitrogen metabolism, spermidine metabolism, and fatty acid metabolism pathways. The study identified metabolites that may be altered in OA, suggesting a role in OA through relevant metabolic pathways. Metabolomics, as an important tool for studying disease mechanisms, provides useful information for studying the metabolic mechanisms of OA.     

Chemical Adsorption Strategy for DMC-MeOH Mixture Separation

The effective separation of dimethyl carbonate (DMC) from its methanol mixture through simple, inexpensive and low energy-input method is a promising and challenging field in the process of organic synthesis. Herein, a reversible adsorption strategy through the assistance of superbase and CO₂ for DMC/methanol separation at ambient condition was described. The process was demonstrated effectively via the excellent CO₂ adsorption efficiency. Notably, the protocol was also suitable to other alcohol (i.e., monohydric alcohol, dihydric alcohol, trihydric alcohol) mixtures. The study provided guidance for potential separation of DMC/alcohol mixture in the scale-up production.     

白花蛇舌草免疫多糖结构的研究

白花蛇舌草(Hedgotis diffusa willd)系茜草科(Rubiaceae)耳草植物,民间常用此草内服治疗小儿疳疾、毒蛇咬伤、癌肿及肠道疾病,外用治疗各种疮疥及跌打刀伤等症.本文首次报道从白花蛇舌草水溶性成份中分离得到一个具有免疫活性的多糖,并对它的结构进行了初步的探讨.     

Manipulating active layer morphology of molecular donor/polymer acceptor based organic solar cells through ternary blends

The development of molecular donor/polymer acceptor blend(MD/PA)-type organic solar cells(OSCs) lags far behind other type OSCs. It is due to the large-size phase separation morphology of MD/PAblend, which results from the high crystallinity of molecular donors. In this article, to suppress the crystallinity of molecular donors, we use ternary blends to develop OSCs based on one polymer acceptor(P-BNBP-f BT) and two molecular donors(DR3 TBDTT and BTR) with similar chemical structures.The ternary OSC exhibits a power conversion efficiency(PCE) of 4.85%, which is higher than those of the binary OSCs(PCE=3.60% or 3.86%). To our best knowledge, it is the first report of ternary MD/PA-type OSCs and this PCE is among the highest for MD/PA-type OSCs reported so far. Compared with the binary blends, the ternary blend exhibits decreased crystalline size and improved face-on orientation of the donors. As a result, the ternary blend exhibits improved and balanced charge mobilities, suppressed charge recombination and increased donor/acceptor interfacial areas, which leads to the higher shortcircuit current density. These results suggest that using ternary blend is an effective strategy to manipulate active layer morphology and enhance photovoltaic performance of MD/PA-type OSCs.     

Ag(I)/(nC7H15)4NBr催化氨基甲酸盐和炔丙醇反应:二氧化碳定量转化制备β-羰基氨基甲酸酯

将一种简单的双组分催化体系即Ag（I）/（ⁿC₇H₁₅）₄NBr应用于常压下催化氨基甲酸盐和炔丙醇双组分反应制备β-羰基氨基甲酸酯。该方法具有简便、高效的优点,并且不需要使用配体,可以将一系列的炔丙醇和仲胺底物转化为相应的氨基甲酸酯产物。该方法通过CO₂的定量催化转化,提高了CO₂的利用效率。