Objective To investigate the effects of erigeron breviscapus (Vant.) Hand-Mazz (erigeron breviscapus) pretreatment on pathology and oxyradical level in the spinal cord after ischemia-reperfusion (I/R) injury in rabbit...Objective To investigate the effects of erigeron breviscapus (Vant.) Hand-Mazz (erigeron breviscapus) pretreatment on pathology and oxyradical level in the spinal cord after ischemia-reperfusion (I/R) injury in rabbits. Methods A total of 40 New Zealand white rabbits were randomly divided into three groups: sham-operation group with 10 rabbits treated with only abdominal aorta exposure without occlusion,control group with 15 rabbits that underwent ischemia for 50 minutes and treated with matched saline,and experimental group with 15 rabbits that underwent ischemia for 50 minutes and treated with erigeron breviscapus (9mg/kg) injection before ischemia. Malondialdehyde (MDA) level and superoxide dismutase (SOD) activity in the spinal cord were examined at 6 and 24 hours after I/R,respectively. The morphological changes and the number of the spinal cord anterior horn motor neurons were observed and counted under the light microscope and electron microscope,respectively. Results The level of MDA was markedly decreased and SOD activity was increased in the experimental group compared with those in the control group (P<0.01). Compared with that in the control group,the number of motor neurons in the experimental group significantly increased at 24h after I/R (P<0.01) and the morphous of the motor neurons improved. Conclusion Erigeron breviscapus can reduce oxyradical production and the apoptosis of nerve cells,and protect nerve tissue structure and function after spinal cord I/R.展开更多
Water is the most abundant liquid on the surface of the earth. It is a liquid whose properties are quite surprising, both as a pure liquid and as a solvent. Water is a very cohesive liquid: its melting and vaporizatio...Water is the most abundant liquid on the surface of the earth. It is a liquid whose properties are quite surprising, both as a pure liquid and as a solvent. Water is a very cohesive liquid: its melting and vaporization temperatures are very high for a liquid that is neither ionic nor metallic, and whose molar mass is low. Thus, water remains liquid at atmospheric pressure up to 100C while similar molecules such as H2S, H2Se, H2Te for example would give a vaporization temperature close to 80C. This cohesion is in fact ensured by hydrogen bonds between water molecules. This type of bonds between neighboring molecules, hydrogen bonds, is quite often found in chemistry [1] [2]. Any change in the state of aggregation of a substance occurs with the absorption or release of a certain amount of latent heat of transformation. Latent heat of fusion, vaporization or sublimation is the ratio of the energy supplied as heat to the mass of the substance that is melted, vaporized or sublimated. As a result of the reversibility of the processes, the fusion heat is equal to the heat released in the reverse process: crystallization and solidification heat. And likewise the heat of vaporization is equal to the heat of condensation. This equality of heat is often used to determine experimentally either of these quantities. There are two main measurement methods: 1) Direct measurement using the calorimeter, 2) Indirect measure based on the use of the VantHoff relationship. The objective of this work is to measure the latent heat of water vaporization and verify the compatibility of the experimental values with the values given by the tables using the indirect method.展开更多
目的:从艾叶中筛选出一种抗无乳链球菌和海豚链球菌的提取物并探究其体外抗菌活性及机制。方法:通过琼脂平板扩散法筛选出体外抗菌效果优良的艾叶提取物,随后测定其对无乳链球菌和海豚链球菌的最低抑菌浓度,通过观测提取物处理后细菌生...目的:从艾叶中筛选出一种抗无乳链球菌和海豚链球菌的提取物并探究其体外抗菌活性及机制。方法:通过琼脂平板扩散法筛选出体外抗菌效果优良的艾叶提取物,随后测定其对无乳链球菌和海豚链球菌的最低抑菌浓度,通过观测提取物处理后细菌生物被膜的形成、表面疏水性、相对电导率及菌体结构来探究其抗菌机制。结果:筛选出的抗菌效果良好的艾叶提取物为艾叶水提取物(Artemisia argyi water extract,AWE),其可通过抑制菌体生物被膜的形成、降低细菌表面疏水率、升高相对电导率而使细胞膜通透性增加,进而破坏细菌细胞膜和菌体结构。结论:AWE为抗菌效果优良的艾叶水提取物,具有作为无乳链球菌和海豚链球菌的天然抗菌剂的潜力。展开更多
文摘Objective To investigate the effects of erigeron breviscapus (Vant.) Hand-Mazz (erigeron breviscapus) pretreatment on pathology and oxyradical level in the spinal cord after ischemia-reperfusion (I/R) injury in rabbits. Methods A total of 40 New Zealand white rabbits were randomly divided into three groups: sham-operation group with 10 rabbits treated with only abdominal aorta exposure without occlusion,control group with 15 rabbits that underwent ischemia for 50 minutes and treated with matched saline,and experimental group with 15 rabbits that underwent ischemia for 50 minutes and treated with erigeron breviscapus (9mg/kg) injection before ischemia. Malondialdehyde (MDA) level and superoxide dismutase (SOD) activity in the spinal cord were examined at 6 and 24 hours after I/R,respectively. The morphological changes and the number of the spinal cord anterior horn motor neurons were observed and counted under the light microscope and electron microscope,respectively. Results The level of MDA was markedly decreased and SOD activity was increased in the experimental group compared with those in the control group (P<0.01). Compared with that in the control group,the number of motor neurons in the experimental group significantly increased at 24h after I/R (P<0.01) and the morphous of the motor neurons improved. Conclusion Erigeron breviscapus can reduce oxyradical production and the apoptosis of nerve cells,and protect nerve tissue structure and function after spinal cord I/R.
文摘Water is the most abundant liquid on the surface of the earth. It is a liquid whose properties are quite surprising, both as a pure liquid and as a solvent. Water is a very cohesive liquid: its melting and vaporization temperatures are very high for a liquid that is neither ionic nor metallic, and whose molar mass is low. Thus, water remains liquid at atmospheric pressure up to 100C while similar molecules such as H2S, H2Se, H2Te for example would give a vaporization temperature close to 80C. This cohesion is in fact ensured by hydrogen bonds between water molecules. This type of bonds between neighboring molecules, hydrogen bonds, is quite often found in chemistry [1] [2]. Any change in the state of aggregation of a substance occurs with the absorption or release of a certain amount of latent heat of transformation. Latent heat of fusion, vaporization or sublimation is the ratio of the energy supplied as heat to the mass of the substance that is melted, vaporized or sublimated. As a result of the reversibility of the processes, the fusion heat is equal to the heat released in the reverse process: crystallization and solidification heat. And likewise the heat of vaporization is equal to the heat of condensation. This equality of heat is often used to determine experimentally either of these quantities. There are two main measurement methods: 1) Direct measurement using the calorimeter, 2) Indirect measure based on the use of the VantHoff relationship. The objective of this work is to measure the latent heat of water vaporization and verify the compatibility of the experimental values with the values given by the tables using the indirect method.
文摘目的:从艾叶中筛选出一种抗无乳链球菌和海豚链球菌的提取物并探究其体外抗菌活性及机制。方法:通过琼脂平板扩散法筛选出体外抗菌效果优良的艾叶提取物,随后测定其对无乳链球菌和海豚链球菌的最低抑菌浓度,通过观测提取物处理后细菌生物被膜的形成、表面疏水性、相对电导率及菌体结构来探究其抗菌机制。结果:筛选出的抗菌效果良好的艾叶提取物为艾叶水提取物(Artemisia argyi water extract,AWE),其可通过抑制菌体生物被膜的形成、降低细菌表面疏水率、升高相对电导率而使细胞膜通透性增加,进而破坏细菌细胞膜和菌体结构。结论:AWE为抗菌效果优良的艾叶水提取物,具有作为无乳链球菌和海豚链球菌的天然抗菌剂的潜力。
