Recent advances in the compound-oriented and pattern-oriented approaches to the quality control of herbal medicines

The current approaches to the quality control of herbal medicines are either compound-oriented or pattern-oriented, the former targeting specific components with some known chemical properties and the latter targeting all detectable components. The marker approach uses specific chemical compounds with known molecular structures, while the multi-compound approach uses both chemical compounds with known structures and those with partial chemical information e.g. retention times, mass spectra and ultraviolet spectra. Apart from chromatographic techniques, new techniques such as oscillating and electrochemistry fingerprints have been developed for quality control. Chemometric resolution methods are widely used for component deconvolution and data comparison. Pattern recognition techniques are used for authentication of herbal medicines

A Brief Survey on Nonlinear Surface Plasmonics

With the rapid development of optical nonlinearities, the study of nonlinear surface plasmonics becomes more popular. Due to the huge potential application value of surface plasmonics, lots of researches in this field become the hotspot. This paper reviewed the history and basic researches of nonlinear plasmonics and focused on several hot topics attracting global attentions. In addition, we introduced the application status of nonlinear surface plasmonics and draw a conclusion. Meanwhile we outlooked the future developments

Boiling Points Predictions Study via Dimension Reduction Methods: SIR, PCR and PLSR

Abstract: Variable selection is an important tool in QSAR. In this article, we employ three known techniques: sliced inverse regression (SIR), principal components regression (PCR) and partial least squares regression (PLSR) for models to predict the boiling points of 530 saturated hydrocarbons. With 122 topological indices as input variables our results show that these three methods have good performance and perform better than some existing methods in the literature. Key words: Cross-validation, dimension reduction, partial least squares regression, principal component regression, sliced inverse regression. 1

Orthogonalization of block variables by subspace-projection for quantitative structure property relationship (QSPR) research

A subspace-projection method is developed to construct orthogonal block variable, which is originally from some kinds of series of topological indices or quantum chemical parameters. With the help of canonical correlation analysis, the orthogonal block variables were used to establish the structure-retention index correlation model. The regression of only few new orthogonal variables obtained by canonical correlation analysis against retention index shows significant improvement both in fitting and prediction ability of the correlation model. Moreover, the quantitative intercorrelation between the different block variables of topological indices can also be evaluated with the help of the subspace-projection technique proposed in this work

The Stochastic Dynamics for Ecological Tourism System with Visitor Educational Intervention

The ever-increasing visitation in parks and protected areas continues to present a considerable challenge for worldwide land managers with allowing recreational use while preserving natural conditions. In China, the fast expanding visitation in protected areas is quickly damaging the natural resources and precious culture without effective visitor education, while regulation and site management are also gaining very limited efficacy. We propose a differential equation to describe the ecological tourism system. Shown by the theoretical proof and numerical simulation, the ecological tourism system is unstable without any perturbed factors, especially visitor educational intervention, because the solution of the dynamic system explodes in a finite time given any initial value. Supposing that the intrinsic increasing rate of stakeholders in the systems stochastically perturbed by the visitor educational intervention, we discover that the stochastic dynamic model can effectively suppress the explosion of the solution. As such, we demonstrate that the tourism system can develop steadily and safely even under a large amount of visitors in public vacation, when employing continuous visitor education intervention programmes