ABSTRACT
Objective To investigate the correlation between mechanical properties and hemostatic ability of the sealing hydrogels. Methods The gelation time, elastic modulus, viscous modulus, bursting strength and hemostatic ability of the hyaluronic acid/gelatin hydrogels were measured. Compared with fibrin sealant, gelation time and mechanical parameters were proposed to judge the feasibility of sealing hydrogels to be used for hemostasis in clinic. Results Hydrogels with a long gelation time, low elastic modulus, low viscous modulus and small bursting strength were merely suitable for hemostasis in minor bleeding. The hydrogels with short gelation time, high elastic and viscous modulus and large bursting strength could effectively reduce the blood loss in the cases of massive bleeding. Conclusions The hemostatic ability of a hydrogel was correlated to its gelation time, elastic modulus, viscous modulus and bursting strength. To achieve hemostasis as effective as fibrin sealant, the gelation time of a sealing hydrogel should be less than 120 s, its elastic and viscous modulus should exceed 600 Pa and 120 Pa, respectively. For the damage with diameter of 2 mm in the tissue model, the burst strength should exceed 10.7 kPa and preferably be larger than 16.0 kPa.
ABSTRACT
Bletilla striata has been used as traditional Chinese medicine for several centuries. In recent years, the quality and quantity of wild B. striata plants have declined sharply due to habitat deterioration and human over-exploitation. Therefore, it is of great urgency to evaluate and protect B. striata wild plant resource. In this study, sequence-related amplified polymorphism (SRAP) markers were applied to assess the level and pattern of genetic diversity in twelve populations of B. striata. The results showed a high level of genetic diversity (PPB = 90.48%, H = 0.349 4, I = 0.509 6) and moderate genetic differentiation among populations (G(st) = 0.260 9). Based on the unweighted pair-group method with arithmetic average (UPGMA), twelve populations gathered in three clusters. The cluster 1 included four populations. There are Nanjing, Zhenjiang, Xuancheng and Hangzhou. The seven populations which come from Hubei Province, Hunan Province, Jiangxi Province and Guizhou Province belonged to the cluster 2. The cluster 3 only contained Wenshan population. Moreover, Mantel test revealed significant positive correlation between genetic distances and geographic distances (r = 0.632 9; P < 0.000 1). According to the results, we proposed a series of conservation consideration for B. striata.
ABSTRACT
In this study, 17 kinds of Dendrobium species of Fengdous including 39 individuals were collected from 4 provinces. Mitochondrial gene sequences co I, nad 5, nad 1-intron 2 and chloroplast gene sequences rbcL, matK amd psbA-trnH were amplified from these materials, as well as nrDNA ITS. Furthermore, suitable sequences for identification of Dendrobium species of Fengdous were screened by K-2-P and P-distance. The results showed that during the mentioned 7 sequences, nrDNA ITS, nad 1-intron 2 and psbA-trnH which had a high degree of variability could be used to identify Dendrobium species of Fengdous. However, single fragment could not be used to distinguish D. moniliforme and D. huoshanense. Moreover, compared to other combined fragments, new type combined fragments nrDNA ITS+nad 1-intron 2 was more effective in identifying the original plants of Dendrobium species and could be used to identify D. huoshanense and D. moniliforme. Besides, according to the UPGMA tree constructed with nrDNA ITS+nad 1-intron 2, 3 inspected Dendrobium plants were identified as D. huoshanense, D. moniliforme and D. officinale, respectively. This study identified Dendrobium species of Fengdous by combined fragments nrDNA ITS+nad 1-intron 2 for the first time, which provided a more effective basis for identification of Dendrobium species. And this study will be helpful for regulating the market of Fengdous.