Cytotoxic and novel skeleton compounds from the heartwood of Chamaecyparis obtusa var. formosana

The novel skeleton compounds, chamaecypanone C (3) and obtunorlignan A (4) were isolated from the heartwood of Chamaecyparis obtusa var. formosana. The structure of 3 was elucidated as a dimeric of monoterpene and norlignan with tricyclo[5.2.2.0^2.6]undecane and the structure of 4 was elucidated as a norlignan skeleton by spectroscopic methods. Compound 3 exhibits potent cytotoxic activity against several human cancer cells with IC₅₀ values ranging from 0.19 to 0.52 μM, whereas 4 has no activity.     

Fatigue crack growth simulations of homogeneous and bi-material interfacial cracks using element free Galerkin method

In this paper, quasi-static fatigue crack growth simulations of homogeneous and bi-material interfacial cracks have been performed using element free Galerkin method (EFGM) under mechanical as well as thermo-elastic load. The thermo-elastic fracture problem is decoupled into thermal and elastic problems. The temperature distribution obtained by solving heat conduction equation is used as input in the elastic problem to get the displacement and stress fields. Discontinuities in the temperature and displacement fields are captured by extrinsic partition of unity enrichment technique. The values of stress intensity factors have been extracted from the EFGM solution by domain based interaction integral approach. The standard Paris fatigue crack growth law has been implemented for the life estimation of various model problems. The results obtained by EFGM under mechanical and thermo-elastic loads were compared with those obtained by FEM using remeshing approach.     

Generalized frieze pattern determinants and higher angulations of polygons

Frieze patterns (in the sense of Conway and Coxeter) are in close connection to triangulations of polygons. Broline, Crowe and Isaacs have assigned a symmetric matrix to each polygon triangulation and computed the determinant. In this paper we consider d-angulations of polygons and generalize the combinatorial algorithm for computing the entries in the associated symmetric matrices; we compute their determinants and the Smith normal forms. It turns out that both are independent of the particular d  -angulation, the determinant is a power of d−1$d-1$, and the elementary divisors only take values d−1$d-1$ and 1. We also show that in the generalized frieze patterns obtained in our setting every adjacent 2×2$2\times 2$-determinant is 0 or 1, and we give a combinatorial criterion for when they are 1, which in the case d=3$d=3$ gives back the Conway–Coxeter condition on frieze patterns.     

西党参的最佳采收期

确定西党参的最佳采收期;通过研究二年生、三年生西党参的不同月份的产量、总皂苷含量的动态变化来确定西党参的最佳采收期;二年生、三年生党参产量之间存在显著差异(p＜0.05).党参总皂苷含量在年限之间都无显著差异(p＞0.05).单因素方差分析表明总皂苷含量在相同年限的不同月份之间有极显著差异(p＜0.01);综合考虑产量...     

蓝花喜盐鸢尾和喜盐鸢尾的化学成分比较分析

采用气相色谱-质谱联用法结合计算机谱图检索,对蓝花喜盐鸢尾根的脂溶性成分和喜盐鸢尾根的挥发性进行分析比较.结果表明:蓝花喜盐鸢尾根和喜盐鸢尾根共鉴定出41种成分.二者共有的成分为(E,E)-9,12-十八二烯酸甲酯、(Z)-9-十八烯酸甲酯.蓝花喜盐鸢尾与喜盐鸢尾成分相比较组成和相对含量存在着较大差异.研究结果有利于鸢...     

基于Smith模糊PID控制的温室监控系统设计

针对温室控制系统被控对象模型的时变性、时滞性和易受干扰的问题,设计了一种基于Smith模糊PID控制的温室监控系统。该系统以MSP430F5438A单片机为核心,以PC机为远程监控终端实现了对温室温湿度的实时监测与控制。仿真结果表明：Smith模糊PID控制器具有调节时间快、超调量小、抗干扰能力强、鲁棒性好的优点。该系统与常规PID控制相比,超调量减小了11%,调节时间减小了23%,模型参数改为T=400,τ=130后,比Smith-PID控制超调量减小了15%,调节时间减小了30%。实验测试说明该系统控制精度高、稳定性好,具有很大的实用价值。     

Separation and purification of flavonoid from Taxus remainder extracts free of taxoids using polystyrene and polyamide resin

An efficient separation process of flavonoid from Taxus wallichiana var. mairei remainder extracts free of taxoids was developed in this study. AB‐8 macroporous resin and polyamide resin offered the fine adsorption capacity, and its adsorption rate at 30°C fitted well to the Langmuir and Freundich isotherms. Resin dynamic adsorption and desorption experiments were conducted to optimize the separation process of total flavonoids from T. wallichiana var. mairei remainder extracts free of taxoids. The optimum parameters for adsorption by AB‐8 resin were as follows: (1) the concentration of flavonoids in a sample solution of 5.61 mg/mL with a processing volume of 2 bed volume (BV) (60 mL); (2) for desorption, ethanol–water (80:20, v/v), with 6 BV as an eluent at a flow rate of 2 BV/h. After a one‐run treatment with AB‐8 resin, the content of flavonoids was increased 5.10‐fold from 4.05 to 20.65%. The optimum parameters for adsorption by polyamide resin were as follows: processing volume of 2 BV (30 mL); for desorption, ethanol–water (70:30, v/v), with 8 BV as an eluent at a flow rate of 2 BV/h. After one‐run treatment with polyamide resin, the content of total flavonoids increased from 20.65 to 65.21%. The method will provide a potential approach for large‐scale separation and purification of flavonoid for its wide pharmaceutical use.     

The Fruits of Paris polyphylla Inhibit Colorectal Cancer Cell Migration Induced by Fusobacterium nucleatum-Derived Extracellular Vesicles

Colorectal cancer (CRC) is one of the most common cancers worldwide. Gut microbiota are highly associated with CRC, and Fusobacterium nucleatum was found to be enriched in CRC lesions and correlated with CRC carcinogenesis and metastases. Paris polyphylla is a well-known herbal medicine that showed anticancer activity. The present study demonstrates that P. polyphylla inhibited the growth of CRC cells. In addition, treating with active compounds pennogenin 3-O-beta-chacotrioside and polyphyllin VI isolated from P. polyphylla inhibited the growth of F. nucleatum. We also found that extracellular vesicles (EVs) released from F. nucleatum could promote mitochondrial fusion and cell invasion in CRC cells, whereas active components from P. polyphylla could dampen such an impact. The data suggest that P. polyphylla and its active ingredients could be further explored as potential candidates for developing complementary chemotherapy for the treatment of CRC.     

展毛多根乌头的生物碱化学成分研究

展毛多根乌头(Aconitum karakolicum var. patentipilum W. T. Wang)为毛莨科乌头属植物^[1],是新疆民间常用草药之一,民间称为草乌,主要用于治疗神经痛、牙痛和关节炎等。     

New Steroidal Saponins Isolated from the Rhizomes of Paris mairei

The genus Paris is an excellent source of steroidal saponins that exhibit various bioactivities. Paris mairei is a unique species and has been widely used as folk medicine in Southwest China for a long time. With the help of chemical methods and modern spectra analysis, five new steroidal saponins, pamaiosides A–E (1–5), along with five known steroidal saponins 6–10, were isolated from the rhizomes of Paris mairei. The cytotoxicity of all the new saponins was evaluated against human pancreatic adenocarcinoma PANC-1 and BxPC3 cell lines.