TS-1 zeolite with desirable pore structure, an abundance of acidic sites, and good thermal stability promising as a support for the selective catalytic reduction of NO with NH3 (NH3-SCR). Herein, a ...series of Mn–Fe/TS-1 catalysts have been synthesized, adopting tetraethylenepentamine (TEPA) as a metal complexing agent using the one-pot hydrothermal method. The introduced TEPA can not only increase the loading of active components but also prompts the formation of a hierarchical structure through decreasing the size of TS-1 nanocrystals to produce intercrystalline mesopores during the hydrothermal crystallization process. The optimized Mn–Fe/TS-1(R-2) catalyst shows remarkable NH3-SCR performance. Moreover, it exhibits excellent resistance to H2O and SO2 at low temperatures. The characterization results indicate that Mn–Fe/TS-1(R-2) possesses abundant surface Mn4+ and Fe2+ and chemisorbed oxygen, strong reducibility, and a high Brønsted acid amount. For comparison, Mn–Fe/TiO2 displays a narrower active temperature window due to its poor thermostability.
The bonding between gold and main-group metallic elements (M) featuring Au
-M
polarity, has been studied recently. The gold in the bonds is expected to have the oxidation number of -1, and hence, ...nucleophilic. However, the knowledge of the reactivity of the gold-metal bonds remains limited. Here, we report digold-substituted germanes of the form of R'
Ge(AuPR
)(AuGeR'
) (3a; R = Me, 3b; R = Et), featuring two Au-Ge(IV) and one Au-Ge(II) bonds. DFT calculations of 3a revealed the existence of high-lying σ(Ge-Au) type HOMO and low-lying LUMO with germylene p
nature. A pendular motion of AuPR
group between Ge(IV) and Ge(II) of 3 occurs in the NMR time scale, suggesting that the Ge(II) center has an enhanced electrophilicity to be attacked by the nucleophilic gold (-I) atom. 3a reacts with nucleophilic Cl
and electrophilic MeOTf reagents at Ge(II) and Ge(IV) centers, respectively.
A 2,6‐distyryl‐substituted boradiazaindacene (BODIPY) dye and a new series of 2,6‐p‐dimethylaminostyrene isomers containing both α‐ and β‐position styryl substituents were synthesized by reacting ...styrene and p‐dimethylaminostyrene with an electron‐rich diiodo‐BODIPY. The dyes were characterized by X‐ray crystallography and NMR spectroscopy and their photophysical properties were investigated and analyzed by carrying out a series of theoretical calculations. The absorption spectra contain markedly redshifted absorbance bands due to conjugation between the styryl moieties and the main BODIPY fluorophore. Very low fluorescence quantum yields and significant Stokes shifts are observed for 2,6‐distyryl‐substituted BODIPYs, relative to analogous 3,5‐distyryl‐ and 1,7‐distyryl‐substituted BODIPYs. Although the fluorescence of the compound with β‐position styryl substituents on both pyrrole moieties and one with both β‐ and α‐position substituents was completely quenched, the compound with only α‐position substituents exhibits weak emission in polar solvents, but moderately intense emission with a quantum yield of 0.49 in hexane. Protonation studies have demonstrated that these 2,6‐p‐dimethylaminostyrene isomers can be used as sensors for changes in pH. Theoretical calculations provide strong evidence that styryl rotation and the formation of non‐emissive charge‐separated S1 states play a pivotal role in shaping the fluorescence properties of these dyes. Molecular orbital theory is used as a conceptual framework to describe the electronic structures of the BODIPY core and an analysis of the angular nodal patterns provides a reasonable explanation for why the introduction of substituents at different positions on the BODIPY core has markedly differing effects.
Ready to dye: A new family of 2,6‐distyryl‐substituted boradiazaindacene (BODIPY) dyes have been synthesized and characterized (see figure), and their photophysical properties were investigated and analyzed by carrying out a series of theoretical calculations.
Silymarin has been widely used as a hepatoprotective drug in the treatment of various liver diseases, yet its effectiveness is affected by its poor water solubility and low bioavailability after oral ...administration, and there is a need for the development of intravenous products, especially for liver-targeting purposes. In this study, silymarin was encapsulated in self-assembled nanoparticles of Bletilla striata polysaccharide (BSP) conjugates modified with stearic acid and the physicochemical properties of the obtained nanoparticles were characterized. The silymarin-loaded micelles appeared as spherical particles with a mean diameter of 200 nm under TEM. The encapsulation of drug molecules was confirmed by DSC thermograms and XRD diffractograms, respectively. The nanoparticles exhibited a sustained-release profile for nearly 1 week with no obvious initial burst. Compared to drug solutions, the drug-loaded nanoparticles showed a lower viability and higher uptake intensity on HepG2 cell lines. After intravenous administration of nanoparticle formulation for 30 min to mice, the liver became the most significant organ enriched with the fluorescent probe. These results suggest that BSP derivative nanoparticles possess hepatic targeting capability and are promising nanocarriers for delivering silymarin to the liver.
Background The purpose of this study is to explore the related factors of precocious puberty in children. Methods 1239 children who underwent physical examination in our hospital from January 2020 to ...December 2022 were analyzed, including 198 precocious children and 1041 normal children. According to the age of 198 precocious children and 1041 normal children, 205 normal children were selected, and the remaining 836 normal children were excluded. They were divided into precocious group and normal group. The general data of the two groups were recorded. Logistic regression was used to analyze the influencing factors of precocious puberty in children. Results There were statistically significant differences (P < 0.05) between the two groups in sex, bone age, daily exercise time, E2, FSH, LH, leptin, mother's menarche time, living environment, consumption of nutritional supplements, consumption of foods containing pigments and preservatives, consumption of high-protein foods, and sleeping time. The multifactor logistic regression analysis shows that the risk factors of children's precocious puberty included gender (female), bone age (> 10 years old), and daily exercise time (< 0.9 h), E2 (greater than or equal to 66.00pmol/L), FSH (greater than or equal to 6.00U/L), LH (greater than or equal to 3.50U/L), leptin (greater than or equal to 8.00 micro G/L), mother's menarche time (< 12 years old), living environment (chemical industry zone), consumption of nutritional supplements (often), consumption of high-protein food (often), and sleep time (< 10 h). Conclusion In conclusion, children's gender, bone age, exercise habits, E2, FSH, LH, leptin, mother's menarche time, living environment, eating habits, sleep time and other factors are closely related to precocious puberty in children. Reminding parents to actively prevent related factors in clinical work is helpful to prevent the occurrence of precocious puberty in children. Keywords: Children, Risk factors, Precocious puberty
Active ingredients from highland barley have received considerable attention as natural products for developing treatments and dietary supplements against obesity. In practical application, the ...research of food combinations is more significant than a specific food component. This study investigated the lipid-lowering effect of highland barley polyphenols via lipase assay in vitro and HepG2 cells induced by oleic acid (OA). Five indexes, triglyceride (TG), total cholesterol (T-CHO), low density lipoprotein-cholesterol (LDL-C), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), were used to evaluate the lipid-lowering effect of highland barley extract. We also preliminary studied the lipid-lowering mechanism by Real-time fluorescent quantitative polymerase chain reaction (qPCR). The results indicated that highland barley extract contains many components with lipid-lowering effects, such as hyperoside and scoparone. In vitro, the lipase assay showed an 18.4 % lipase inhibition rate when the additive contents of highland barley extract were 100 µg/mL. The intracellular lipid-lowering effect of highland barley extract was examined using 0.25 mM OA-induced HepG2 cells. The results showed that intracellular TG, LDL-C, and T-CHO content decreased by 34.4 %, 51.2 %, and 18.4 %, respectively. ALT and AST decreased by 51.6 % and 20.7 % compared with the untreated hyperlipidemic HepG2 cells. qPCR results showed that highland barley polyphenols could up-regulation the expression of lipid metabolism-related genes such as PPARγ and Fabp4.
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•In vitro, lipase assay showed that the inhibition rate of lipase reached 18.4 % after adding highland barley extracts.•The content of intracellular TG, LDL-C, T-CHO, ALT and AST were decreased by 34.4 %, 51.2 %, 18.4 %, 51.6 % and 20.7 % after highland barley extracts treatment.•Highland barley extract could up-regulation the expression of lipid metabolism related genes such as PPARγ and Fabp4.
Transposon-associated ribonucleoprotein TnpB is known to be the ancestry endonuclease of diverse Cas12 effector proteins from type-V CRISPR system. Given its small size (408 aa), it is of interest to ...examine whether engineered TnpB could be used for efficient mammalian genome editing. Here, we showed that the gene editing activity of native TnpB from Deinococcus radiodurans (ISDra2 TnpB) in mouse embryos was already higher than previously identified small-sized Cas12f1. Further stepwise engineering of noncoding RNA (ωRNA or reRNA) component of TnpB significantly elevated the nuclease activity of TnpB. Notably, an optimized TnpB-ωRNA system could be efficiently delivered in vivo with single adeno-associated virus (AAV) and corrected the disease phenotype in a tyrosinaemia mouse model. Thus, the engineered miniature TnpB system represents a new addition to the current genome editing toolbox, with the unique feature of the smallest effector size that facilitate efficient AAV delivery for editing of cells and tissues.
The development of autism spectrum disorders (ASDs) involves both environmental factors such as maternal diabetes and genetic factors such as neuroligins (NLGNs). NLGN2 and NLGN3 are two members of ...NLGNs with distinct distributions and functions in synapse development and plasticity. The relationship between maternal diabetes and NLGNs, and the distinct working mechanisms of different NLGNs currently remain unclear. Here, we first analyzed the expression levels of NLGN2 and NLGN3 in a streptozotocin-induced ASD mouse model and different brain regions to reveal their differences and similarities. Then, cryogenic electron microscopy (cryo-EM) structures of human NLGN2 and NLGN3 were determined. The overall structures are similar to their homologs in previous reports. However, structural comparisons revealed the relative rotations of two protomers in the homodimers of NLGN2 and NLGN3. Taken together with the previously reported NLGN2-MDGA1 complex, we speculate that the distinct assembly adopted by NLGN2 and NLGN3 may affect their interactions with MDGAs. Our results provide structural insights into the potential distinct mechanisms of NLGN2 and NLGN3 implicated in the development of ASD.
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