Study on anti-hygroscopic technology based on correlations between particle spatial properties and hygroscopicity of Chinese medicinal extracts / 中国中药杂志

This study was designed to investigate the correlations of the spatial structure properties of Chinese medicinal extracts with hygroscopicity and the anti-hygroscopic techniques. With Poria extract used as the model drug, pregelatinised starch and microcrystalline cellulose at different ratios were added into Poria fluid extract for preparing powder particles with diverse spatial structures using different drying processes. Then, their hygroscopic behaviours were characterized by equilibrium hygroscopicity(F~∞) and semi-hygroscopic time(t_(1/2)). The correlations of the hygroscopicity of each powder with the spatial structure properties such as particle size(D_(90)), porosity(ε), true density(ρ_t), and surface element distribution were analyzed using partial least-squares method. The F~∞ and t_(1/2) values of Poria extract prepared by three drying methods were sorted in a descending order as follows: F~∞(spray drying>drying at ordinary pressure>drying at reduced pressure); t_(1/2)(drying at reduced pressure>drying at ordinary pressure>spray drying). The powder obtained by spray drying showed a spherical structure with the smallest particle size and intra-particle ε but relatively stronger hygroscopicity. The large-scale surface element enrichment of the powders dried by reduced pressure effectively reduced their hygroscopicity. F~∞ and t_(1/2) were negatively correlated with ε but positively with D_(90), and the interactive influence of each spatial structural properties was not significant. There existed a correlation between the spatial structure of the powder particles of Chinese medicine extracts and their hygroscopicity, and the hygroscopicity could be improved by designing the spatial structure. This study has provided some practical basis for developing the moisture-proof technology of Chinese medicinal preparations.

The taxonomic distinctness of macroinvertebrate communities of Atlantic Forest streams cannot be predicted by landscape and climate variables, but traditional biodiversity indices can / A distinção taxonômica de comunidades de macroinvertebrados de córregos da Mata Atlântica não pode ser previsto pela paisagem e por variáveis climáticas, mas os índices de biodiversidade tradicional podem

Predicting how anthropogenic activities may influence the various components of biodiversity is essential for finding ways to reduce diversity loss. This challenge involves: a) understanding how environmental factors influence diversity across different spatial scales, and b) developing ways to measure these relationships in a way that is fast, economical, and easy to communicate. In this study, we investigate whether landscape and bioclimatic variables could explain variation in biodiversity indices in macroinvertebrate communities from 39 Atlantic Forest streams. In addition to traditional diversity measures, i.e., species richness, abundance and Shannon index, we used a taxonomic distinctness index that measures the degree of phylogenetic relationship among taxa. The amount of variation in the diversity measures that was explained by environmental and spatial variables was estimated using variation partitioning based on multiple regression. Our study demonstrates that taxonomic distinctness does not respond in the same way as the traditional used in biodiversity studies. We found no evidence that taxonomic distinctness responds predictably to variation in landscape metrics, indicating the need for the incorporation of predictors at multiple scales in this type of study. The lack of congruence between taxonomic distinctness and other indices and its low predictability may be related to the fact that this measure expresses long-term evolutionary adaptation to ecosystem conditions, while the other traditional biodiversity metrics respond to short-term environmental changes.

Prever como as atividades antrópicas podem influenciar os vários componentes da biodiversidade é essencial para encontrar maneiras de reduzir a perda de diversidade. Este desafio envolve: a) a compreensão de como os fatores ambientais influenciam a diversidade em diferentes escalas espaciais e, b) desenvolver formas de medir essas relações de uma maneira rápida, econômica e de fácil comunicação. Neste estudo, nós investigamos se a paisagem e as variáveis bioclimáticas podem explicar a variação nos índices de biodiversidade em comunidades de macroinvertebrados de 39 riachos de Mata Atlântica. Adicionalmente às medidas tradicionais de diversidade, por ex.: riqueza de espécies, abundância e índice de Shannon, nos utilizamos índice de distinção taxonômica que mede o grau de relação filogenética dentre os taxa. A quantidade de variação nas medidas de diversidade que foi explicado por variáveis ambientais e espaciais foi estimada utilizando a variação particionada baseada em regressão múltipla. O presente estudo demonstra que o índice de distinção taxonômica não responde da mesma maneira que os índices tradicionais utilizados em estudos de biodiversidade. Nós não encontramos nenhuma evidência de que a distinção taxonômica responde previsivelmente à variação métricas da paisagem, indicando a necessidade de incorporação de preditores em múltiplas escalas neste tipo de estudo. A falta de congruência entre a distinção taxonômica e outros índices e sua baixa previsibilidade pode estar relacionada com o fato de esta medida expressar adaptações evolutivas de longo prazo para as condições ambientais, enquanto as outras métricas tradicionais respondem às alterações ambientais de curto prazo.

Evaluation and applications of antibody variable stability / 军事医学

Objective To study the intrinsic relationships between the binding energy of the antibody light and heavy chains and the conformational characteristics , physical and chemical properties , and to establish a corresponding mathemat-ical model and evaluate the thermal stability of the antibody molecules , which contribute to the antibody design , optimiza-tion and affinity maturation .Methods Based on bioinformatics and computational biology methods , the antibody′s structur-al information with the crystal diffraction data was analyzed .The conformational character of the variable domain of the antibody was studied using distance geometry and computer graphics technology .With the aid of the intermolecular hydrogen bond formation theory and the reaction free energy theory , the dynamic structure and energy characteristics be-tween the heavy and light chain variable regions of the antibody were studied .Furthermore , using nonlinear fitting and regression analysis, a mathematical model was set up .Results According to simulation and statistic analysis , there was a linear relationship between the binding energy and the number of the intermolecular hydrogen bonding , Van der Waals interaction of the heavy and light chains of the antibody .There was polynomial correlation between the binding energy and the physicochemical properties of the antibody .Using the frequency of amino acid position and the established model , the humanized anti-ricin antibody , which could not obtain the stable engineering cell line , was evaluated and optimized .The stable engineering cell line of the humanized anti-ricin antibody was obtained in the experiment .Conclusion The self structure of the antibody variable region ( conformation and physicochemical properties ) has much effect on its stability . The antibody stability can be improved by structural optimization .