Stereoselective synthesis of l-isoxazolidinyl thymidine from N-benzyl-1,2-di-O-isopropylidene-d-glyceraldehyde nitrone (BIGN)

A synthetic approach to l-isoxazolidinyl nucleosides is demonstrated by the stereoselective conversion of N-benzyl-1,2-di-O-isopropylidene-d-glyceraldehyde nitrone (BIGN) into cis and trans l-isoxazolidinyl thymidine. The methodology consists of the 1,3-dipolar cycloaddition of BIGN with either vinyl acetate or a vinyl base to give key intermediates that are easily transformed into the target compound. The experimental results of the cycloaddition reactions can be qualitatively explained by theoretical ab initio calculations.     

A general three-step one-pot synthesis of novel (<Emphasis Type="Italic">E</Emphasis>)-6-chloro-2-(aryl/hetarylvinyl)quinoline-3-carboxylic acids

In this work, a facile and general three-step one-pot synthesis of structurally new (E)-6-chloro-2-(aryl/hetarylvinyl)quinoline-3-carboxylic acid derivatives has been achieved from easily available ethyl 6-chloro-2-(chloromethyl) quinoline-3-carboxylate and aromatic or heteroaromatic aldehydes. This strategy features simple one-pot operation, tolerance of a wide range of substituents, and good yields. Moreover, these newly synthesized compounds belong to a new class of quinoline derivatives and could be good candidates for the development of more complex quinoline compounds for use in medicinal chemistry.     

纳米晶304不锈钢高温氧化膜中Cr和Mn元素的XPS和UPS表征

利用X射线光电子能谱（XPS）和紫外光电子能谱（UPS）,对比研究了普通304不锈钢（CP-SS304）和深度轧制技术制备的块体纳米晶304不锈钢（BN-SS304）在900 ℃空气中氧化24 h后形成的高温氧化膜中Cr和Mn元素的结合能、原子百分比、价电子的相互作用和功函数,分析了BN-SS304表面电子结构的特征。结果表明：两种材料氧化膜中Cr元素以Cr3+和Cr0存在,Mn元素以Mn4+和Mn0存在,在不同溅射时间,BN-SS304氧化膜中Cr3+与（Cr3++Cr0）原子百分比和Mn4+与（Mn4++Mn0）原子百分比均低于CP-SS304氧化膜中的比值。两种材料氧化膜中价电子之间的相互作用主要有Mn—O,Cr—O,Mn0(3d和4s)和Cr0(3d和4s)。与CP-SS304相比,BN-SS304氧化膜表面价电子之间的相互作用强,其功函数比CP-SS304提高0.07 eV, BN-SS304的耐高温氧化性能增强。     

Electrolytic behavior and application to lithium batteries of monofluorinated dimethyl carbonate

Dimethyl carbonate (DMC) was fluorinated by F₂ gas (direct fluorination) to form four fluorinated DMC derivatives, such as monofluorinated DMC (MFDMC), two difluorinated DMCs (DFDMC(a) and DFDMC(b)) and trifluorinated DMC (TFDMC). The electrolytic behavior and charge–discharge characteristics of the lithium electrode were examined in MFDMC and MFDMC-ethylene carbonate (EC) equimolar binary solutions. The dielectric constant and viscosity of MFDMC are higher than those of DMC. This means that the molecular interaction in MFDMC becomes larger due to the introduction of a high electron withdrawing fluorine atom. In addition, oxidation durability of MFDMC is higher than that of DMC. The specific conductivity in EC-MFDMC equimolar binary solution containing 1 M LiPF₆ is 8.5 mS cm^− 1 at 25 °C which means a good electrolyte for lithium batteries. The lithium electrode cycling efficiency in EC-MFDMC equimolar binary solution containing 1 M LiPF₆ is higher than 70%. The surface of the film formed on the electrode in the solution is homogeneous, and consists of the uniform and small grain size.     

Anti-inflammatory spirobisnaphthalene natural products from a plant-derived endophytic fungus Edenia gomezpompae

Spirobisnaphthalenes comprise a relatively rare family of natural products that are normally isolated from fungi and occasionally from plants.Here we reported the discovery of seven new preussomerintype spirobisnaphthalenes,preussomerins YT1-YT7(1-7),and seven known ones(8-14),from the endophytic fungus Edenia gomezpompae,enriching the structural diversity of this family of natural products.Their structures were established by 1 D and 2 D NMR spectroscopy,HRESIMS analysis and comparison with previously reported compounds,with the absolute configurations of compounds 1 and2 being further confirmed by single-crystal X-ray diffraction using Cu Ka radiation.The antiinflammatory activities of all isolates were assessed by measuring the production of NO in LPS-induced RAW2 64.7 macrophage cells.Among them,compounds 8 and 13 exhibited potent inhibitory activities on the production of NO,with IC_(50) values of 2.61 and 1.32 μmol/L,respectively.     

Effects of ultrasonic pretreatment of soybean protein isolate on the binding efficiency,structural changes,and bioavailability of a protein-luteolin nanodelivery system

The combination of protein and flavonoids can ameliorate the problems of poor solubility and stability of flavonoids in utilization. In this study, soybean protein isolate pretreated by ultrasonication was selected as the embedding wall material, which was combined with luteolin to form a soybean protein isolate-luteolin nanodelivery system. The complexation effect and structural changes of soybean protein isolate (SPI) and ultrasonic pretreatment (100 W, 200 W, 300 W, 400 W and 500 W) of soybean protein isolate with luteolin (LUT) were compared, as well as the changes in digestion characteristics and antioxidant activity in vitro. The results showed that proper ultrasonic pretreatment increased the encapsulation efficacy, loading amount and solubility to 89.72%, 2.51 μg/mg and 90.56%. Appropriate ultrasonic pretreatment could make the particle size and the absolute value of ζ-potential of SPI-LUT nanodelivery system decrease and increase respectively. The FTIR and fluorescence results show that appropriate ultrasonic pretreatment could reduce α-helix, β-sheet and random coil, increase β-turn, and enhance fluorescence quenching. The thermodynamic evaluation results indicate that the ΔG < 0, ΔH > 0 and ΔS > 0, so the interaction of LUT with the protein was spontaneous and mostly governed by hydrophobic interactions. The XRD results show that the LUT was amorphous and completely wrapped by SPI. The DSC results showed that ultrasonic pretreatment could improve the thermal stability of SPI-LUT nanodelivery system to 112.66 ± 1.69 °C. Digestion and antioxidant analysis showed that appropriate ultrasonic pretreatment increased the LUT release rate and DPPH clearance rate of SPI-LUT nanodelivery system to 89.40 % and 55.63 % respectively. This study is a preliminary source for the construction of an SPI nanodelivery system with ultrasound pretreatment and the deep processing and utilization of fat-soluble active substances.     

Non-perturbative contributions to the hot electroweak potential and the crossover

We discuss non-perturbative contributions to the three-dimensional 1-loop effective potential of the electroweak theory at high temperatures in the framework of the stochastic vacuum model. It assumes a gauge-field background with Gaussian correlations which leads to confinement. The instability of 〈F²〉 = 0 in Yang-Mills theory appears for small Higgs expectation value 〈φ²〉 in an IR regularized form. The gauge-boson propagator obtains a positive momentum-dependent “diamagnetic” effective (mass)² due to confinement effects and a negative one due to “paramagnetic” spin-spin interactions which are related to the 〈F²〉 = 0 instability. Numerical evaluation of an approximate effective potential containing these masses shows qualitatively the fading away of the first-order phase transition with increasing Higgs mass which was observed in lattice calculations. The crossover point can be roughly determined postulating that the effective φ⁴ and φ² terms vanish there.     

Optimization of extraction process of Dioscorea nipponica Makino saponins and their UPLC-QTOF-MS profiling,antioxidant, antibacterial and anti- inflammatory activities

Dioscorea nipponica Makino exhibits many biological activities, including relieving cough, eliminating phlegm and preventing asthma. The present study extensively evaluated the extraction process, major components, antioxidant, antibacterial and anti-inflammatory activities of total saponins extraction from Dioscorea nipponica Makino. In this study, the optimal extraction process of total saponins extract was optimized by single-factor test and response surface methodology as follows: extraction time 25 min, ethanol concentration 50 % and liquid to material ratio 55:1 ml/g, and the extraction rate was 1.72 %. Eighteen components were initially analyzed by UPLC-QTOF-MS method. Although total saponins extract exhibited mild antibacterial activities against Escherichia coli, Salmonella, Staphylococcus aureus and Streptococcus, and antioxidant activities against ferric-ion, ABTS and DPPH radicals, the perfect anti-inflammatory activity of TSE was demonstrated by significantly reducing the content of NO and the phagocytic activity in LPS induced RAW 264.7 cells, which provided a theoretical basis for the research and development of new anti-inflammatory Chinese medicine.     

Cell membrane-coated mesoporous silica nanorods overcome sequential drug delivery barriers against colorectal cancer

Local delivery of nanomedicines holds therapeutic promise for colorectal cancer (CRC). However, it presents tremendous challenges due to the existence of multiple physiological barriers, especially intracellular obstacles, including intracellular trafficking, subcellular accumulation, and drug release. Herein, we report a multifunctional nanoparticle (CMSNR) by wrapping the mesoporous silica nanorod with cell membrane derived from CRC cells for improved chemotherapy. Compared with their naked counterparts, the cell membrane endowed CMSNR with homotypic targeting and improved cellular uptake capacities. Due to the rod-like shape, CMSNR achieved superior colorectal mucus permeability, enhanced tumor accumulation, and boosted cellular uptake than their spherical counterparts. Moreover, the internalized CMSNR underwent robust intracellular trafficking and gained augmented motility toward the nucleus, leading to efficient perinuclear accumulation and a subsequent 5.6-fold higher nuclear accumulation of loaded drug than that of nanospheres. In the orthotopic colorectal tumor-bearing nude mice, rectally administrated mefuparib hydrochloride (MPH)-loaded CMSNR traversed the colorectal mucus, penetrated the tumor tissue, and successfully aggregated in the perinuclear region of cancer cells, thus exhibiting significantly improved antitumor outcomes. Our findings highlight the shape-based design of cell membrane-coated nanoparticles that can address sequential drug delivery barriers has a promising future in cancer nanomedicine.