Sinuhirtins A and B,two uncommon norhumulene-type terpenoids from the South China Sea soft coral Sinularia hirta

Two new uncommon norhumulene-type norsesquiterpenoids, namely sinuhirtins A (1) and B (2), along with two known norcaryophyllene-type norsesquiterpenoids (3 and 4), were isolated from the South China Sea soft coral Sinularia hirta. The structures and absolute configurations of the new compounds were determined by extensive spectroscopic data analyses, and computer-assisted methods including GIAO ¹³C NMR and TDDFT-ECD calculations. A plausible biogenetic relationship of 1–4 was proposed.     

数字图像一阶矩的自动聚焦区域选择算法

聚焦区域选择是自动聚焦算法中的重要模块,直接影响评价函数曲线的尖锐性、准确性和稳定性。针对中心取窗和多点取窗等传统聚焦区域选择算法的局限性,提出了一种基于数字图像一阶矩的自动聚焦区域选择算法,它是通过图像灰度或边缘一阶矩定位聚焦区域的。传统聚焦区域选择是一种定点估计,实验证明一阶矩方式选择可以跟踪偏离中心的主体景物,是一种具有自适应性的前景位置估计算法,提高了聚焦精确度和速度。     

Untargeted Identification of Black Rice by Near-Infrared Spectroscopy and One-Class Models

Black rice is one of the famous rare rice varieties in China. It is common to sell inferior black rice intentionally declared as famous brands due to economical motivation. There is an urgent need to develop an analytical method for untargeted identification of black rice. The present work focuses on exploring the feasibility of the untargeted identification of black rice by the combination of near-infrared (NIR) spectroscopy and data driven-based class modeling and variable selection. A total of 142 samples of three brands were collected and used for measurements. The samples of a specific class were used as the target class. Principal component analysis was applied for the preliminary analysis. The model-independent variable selection method, i.e., joint mutual information, was used for spectral compression. Only the 10 most informative variables were picked from original variables based on which an optimal class-model for the target class was constructed and validated by means of an external test set. As a result, the model achieved 100% of sensitivity and specificity. It can be concluded that NIR spectroscopy combined with one-class modeling is a feasible tool for the untargeted identification of black rice.     

Nondestructive Discrimination of Pharmaceutical Preparations Using Near-Infrared Spectroscopy and Partial Least-Squares Discriminant Analysis

Metronidazole is a widely used antibacterial and amoebicide drug. The feasibility of the classification of metronidazole samples with respect to their brands was investigated by near-infrared (NIR) spectroscopy along with chemometrics. A total of 92 samples of different lots and four brands were collected for measurements. First, principal component analysis was conducted to visualize the difference between metronidazole samples of different brands. Then, based on an effective classifier-independent method, i.e., joint mutual information, only the 30 most important variables were selected for modeling. From the independent test set, the partial least-squares discriminant analysis model based on the reduced variable set was compared with the corresponding full-spectrum model using all variables, which indicates the model based on the reduced variable set outperforms the full-spectrum model. It appears that the combination of NIR spectroscopy, joint mutual information, and partial least-squares discriminant analysis is a potential method for the classification of metronidazole from different brands and can, therefore, be used in the screening of counterfeit pharmaceutical products.     

Photocatalysis effect of nanometer TiO2 and TiO2-coated ceramic plate on Hepatitis B virus

The photocatalysis effect of nanometer TiO2 particles and TiO2-coated ceramic plate on Hepatitis B virus surface antigen (HBsAg) was investigated. The ELISA (enzyme-linked immunosorbent assay) standard method was used to assess the efficiency of TiO2 material to destroy the HBsAg. The research has shown that the suspension of TiO2 (0.5g/L) can destroy most of the HBsAg under the irradiation of mercury lamp, with the light intensity of 0.6mW/cm(2) at 365nm wavelength, or under the sunlight irradiation for a few hours. TiO2-coated ceramic plates can also destroy the HBsAg under the irradiation of mercury lamp, with the light intensity of 0.05mW/cm(2) at 365nm wavelength or under the room daylight for a few hours.     

复杂系统的泛系聚类方法

本文利用半等价算子ε_i和相等化算子δ_i研究了复杂系统的聚类问题;阐述了分析运筹复杂系统的δ(1,3)解耦原理、对偶转化原理和大系统分解原理;详细讨论了复杂系统的连通性与解耦性并提供了有关定理.最后,利用泛系聚类方法讨论了复杂系统的层次分析.     

Research on the complicated dynamical behaviors of nonlinear ecosystems (II)

This paper is a further study of reference [1]. In this paper, we mainly discuss the complicated dynamical behaviors resulting from a simple one-dimensional model of nonlinear ecosystems: fixed point motion, periodic motion and chaotic motion etc., and briefly discuss the universality of the complicated dynamical behaviors, which can be described by the first and the second M. Feigenbaun. constants. At last, we discuss the one-side lowering phenomenon due to near unstabilization when the nonlinear ecosystem approaches bifurcation points from unbifurcation side. It is of important theoretical and practical meanings both in the development and utilization of ecological resources and in the design and management of artifitial ecosystems.Supported by the Youth Science Fundation of Chinese Academia Sinica and Youth Fundation of Lanzhou Unviersity.     

Operation analysis of natural resources and their pan-weighted network models

In this paper, we propose a competition-share 3-category principle, on which we unite the problems of natural resources, energy, population and environment and so on into a mutual scheme, and provide a united model for the comprehensive research on these problems. This makes the idea of operation analysis of natural resources clearer and the relationships between each of their parts more obvious. On the basis of the above discussion, we propose mathematical models for the operation analysis of multi-networks and the solution of the above global comprehensive problems. We discuss, especially, Shengke (growth and restraint) relationships between two networks of natural resources and share-competitors and their analysis models, providing mathematical tools for solving the problems of the resource-population and the resource-economy, etc. Supported by Science Fund of Lanzhou University.     

婴幼儿奶瓶中迁移双酚A的高效液相色谱-电喷雾串联质谱检测方法研究

建立了婴幼儿奶瓶中双酚A(BPA)迁移量的高效液相色谱-电喷雾串联质谱(HPLC-ESI-MS/MS)测定方法。奶瓶食品模拟浸泡液经过弗罗里硅土玻璃层析柱净化,高效液相色谱分离,采用选择反应性监测模式(SRM)检测。以一级质谱得到的准分子离子m/z 227作为母离子,进行二级质谱(MS2)分析。选择MS2的碎片离子m/z 212、133、93定性确证,m/z 212作为定量离子定量。实验优化了质谱条件,并对二级质谱碎裂机理和特征离子进行了研究。测定结果的相对标准偏差不大于8.2%(n=7),回收率在87.7%～105%之间;检出限为2μg/L,能够满足欧盟、美国等对奶瓶中双酚A的限制要求。该法已成功应用于婴幼儿奶瓶中BPA迁移量的测定。