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31.
为了保持牛奶的新鲜程度,防止牛奶变酸和细菌数升高,各个规模牛场和收奶站均配备了牛奶冷却设备,同时还需要通过锅炉或电加热等方式生产大量的热水来清洗设备。利用锅炉或电加热生产热水不但浪费了大量的财力、物力和人力,还造成了环境污染。现介绍一种不额外消耗能源解决热水供应的方法,供大家参考。1原理冷冻机在制冷的同时,产生大于制冷量的热量。压缩机高压出来的温度一般超过90℃以上,这部分热量一般经过风冷的方式通过散热器散发到室外。特别是夏天,气温较高,散热器散热效率较低,需要浪费大量的冷却水冷却,即使这样,有时温度还是降不…  相似文献   
32.
The morphological features of blood and milk neutrophils from peak lactating goats were compared using light microscopy, scanning electron microscopy and flow cytometry in order to investigate the cytological changes of neutrophils after migration into the mammary gland. The kinetics of reactive oxygen intermediates (ROI) generation and gelatinase release of blood and milk neutrophils, with or without stimulation of phorbol 12-myristate, 13-acetate ester (PMA), were used to characterize their responses to inflammatory stimuli. Neutrophils isolated from goat milk were highly segmented and contained multi-lobed nuclei. Ultrastructurally, milk neutrophils were more ruffled on the surface compared to blood neutrophils. Approximately 30% of milk neutrophils were undergoing cell death, either necrosis or apoptosis, in contrast to 8% of blood neutrophils. The ROI production of activated milk neutrophils peaked earlier than blood neutrophils, but the duration and the intensity were much less. Neutrophils from both sources augmented the release of gelatinase in response to PMA (1 ng/mL). However, the amount of gelatinase released from milk neutrophils was lower (P < 0.05) than that of blood neutrophils. In summary, more neutrophils become apoptotic and necrotic in the mammary gland, presumably due to spontaneous aging, the process of diapedesis, and the interaction with milk components. Milk neutrophils have impaired functionalities in comparison with blood neutrophils. The information is relevant when studying mammary gland immunity and related diseases, such as mastitis.  相似文献   
33.
AIM:To investigate the effects of Liucha extract on the growth of tumor cells in vitro and its possible mechanism.METHODS:The capability of colony forming of human leukemia K562 cell in vitro and the cells metabolism were studied by semi-solid agar culture and MTT staining. Then , the changes in morphology in the tumor cells were examined using electronic microscope.RESULTS:Semi-solid agar culture and MTT colorimetric analysis showed that Liucha extrats could significantly inhibit the growth of the tumor cells and their capability of colony forming. Also,under the electronic microscope,it was found that the tumor K562 cell had a narrower perinuclear space,condensation of chromatin and an enlarged mitochondria , in which the cristase disappeared.CONCLUSION:The extract from Liucha possesses an inhibitory effect on K562 cell growth in vitro through affecting the metabolism of the tumor cells.  相似文献   
34.
位于黄土高原中部的陕甘宁老区生态环境极为脆弱 ,近年来由于气候、人类开发资源等自然和人为原因 ,使生态环境的脆弱程度升高。选定年降水量、年均温、蒸发量等 8个指标 ,定量评价各县 1 970 - 2 0 0 0年的脆弱度状况 ,结果表明榆林、延安两市生态环境整体脆弱 ,脆弱度存在空间差异但差异不明显 ,时间段上的波动幅度不大。陕甘宁老区脆弱生态环境具有不稳定性 ,对外界干扰较敏感。  相似文献   
35.
不同粘度矿物油助剂对除草剂活性的影响   总被引:5,自引:1,他引:5  
室内及温室内测定了10种不同粘度矿物油助剂对除草剂防除苘麻和稗草药效的影响及对玉米苗期的安全性。结果表明,10种矿物油助剂均不同程度地增加了氰草津和烟嘧磺隆防除两种杂草的活性。其中粘度为46 mm2/s (40℃)的矿物油乳剂(MOC46)对供试除草剂药效的增强作用最为明显,其次为粘度32 mm2/s (40℃)的矿物油乳剂。10种助剂对氰草津药效的增强作用大于对烟嘧磺隆。MOC46对除草剂活性的增加由高到低依次为:莠去津、氰草津>莠去津+氰草津、莠去津+烟嘧磺隆、氰草津+烟嘧磺隆>烟嘧磺隆;对玉米苗期安全性依次为:莠去津、烟嘧磺隆、莠去津+烟嘧磺隆>莠去津+氰草津、氰草津+烟嘧磺隆>氰草津。氰草津与MOC46混用对玉米苗期药害较重。  相似文献   
36.
姬松茸与双孢蘑菇不同菌株的RAPD扩增研究   总被引:6,自引:1,他引:6  
以4个姬松茸菌株和2个双孢蘑菇菌株为材料,用20个随机引物对它们进行RAPD扩增,通过对供试菌株遗传相似系数的估算和系统聚类分析,构建姬松茸和双孢蘑菇遗传相关树状聚类图谱,结果表明,进行RAPD扩增的20个随机引物中,有12个能产生三种带型,当遗传相似系数升至0.8713时,这6个菌株被分为3类,第一类为菌株18和26,第二类为菌株13和12,第三类为菌株33和45。  相似文献   
37.
AIM:To establish rat chronic obstructive pulmonary disease(COPD) models by passive cigarette smoking plus intratracheal instillation of lipopolysacchride(LPS) or passive cigarette smoking only, which would be similar to the pathogenesis of human COPD. METHODS:48 Wistar rats were randomly divided into 4 groups.(1) Healthy control I group(n=12), rats were bred 4 weeks;healthy control II group(n=12), rats were bred for 3months. (2) Model group I (n=12), 200μg lipopolysaccharide(LPS) was instilled intratracheally once for every two weeks and the rats were exposured to 5% of cigarette smoke, 0.5 h/d for 4 weeks.(3) Model group II(n=12),rats were exposed to 5% of cigarette smoke, 0.5 h/d for 3 months. The pathologic changes of airways and lung tissues, pulmonary function and blood gas analysis were determined. The airway wall lymphocytes and alveolar macrophages were counted. The cross areas of epithelial layer, smooth muscle layer and lamina propria of bronchi were measured. The hydroxyproline of lung tissue homogenates was determined by biochemistry method.RESULTS:The pathologic changes of airways and lung tissue of two models were similar to but milder than those of COPD patients(biopsy data). The collagen deposition and the cross areas of epithelial layer and smooth muscle layer in airway walls of two model groups were significantly increased than those of control groups(P<0.01,P<0.05).FEV0.3/FVC% of two model groups, PaO2 and SaO2 of model I group were significantly decreased, while Ri and Re in model I group were significantly increased than that of control I group(P<0.05). The PaCO2 and the counts of lymphocytes and alveolar macrophages of both model groups were significantly increased than those of the control groups (P<0.01). Lots of alveolar macrophages had phagocyted smoke granules. The amounts of hydroxyproline of two model groups were significantly increased than those of control group((P<0.05) and were negatively related to the FEV0.3/FVC%, respectively (P<0.01,P<0.01) and positively related to airway resistance of model I group(P<0.01). CONCLUSIONS:COPD rat models were successfully established by passive cigarette smoking plus intratracheal instillation of LPS and cigarette smoking only. The pathologic changes were similar but milder than those of COPD patients. The airway obstruction of model I group was more severe than that of model II group, but they have no significant difference.  相似文献   
38.
AIM: To investigate the relationship between somatostatin and the pathologic type, estrogen receptor,DNA ploidy of nuclei in tumor cells of breast cancer.METHODS: 67 cases of primary breast cancer and 25 cases of benign breast tumor were examined by immunohistochemical stretomyces avidin peroxidase method. 26 cases of breast cancer selected at random were analyzed by flow cytometry.RESULTS: Somatostatin expressed significantly higher in low malignant breast cancer than that in high malignant breast cancer (P<0.05). Most of cancers with positive staining of somatostatin were diploidy,most of cancers with negative staining were aneuploidy,there had significant difference between two groups (P<0.05).CONCLUSION: Somatostatin may delay the progress of breast cancer,and somatostatin levels in cancer tissues may become a useful indicator for assessing prognosis of patients with breast cancer.  相似文献   
39.
本文采用5%OV-17为色谱柱固定相,以邻苯二甲酸二正戊酯为内标物,用FID检测器对2%甲嘧磷 马粉剂进行定量分析,甲基嘧啶磷、马拉硫磷的标准偏差分别为0.027、0.011,变异系数分别为2.40%、0.99%; 甲基嘧啶磷回收率为99.5%-100.3%,马拉硫磷的回收率为98.9%~99.8%o该方法方便、快捷、准确。  相似文献   
40.
 甘薯由于甘薯病毒的普遍存在而造成大幅度减产。甘薯病毒种类复杂,主要有甘薯羽状斑驳病毒(SPFMV)、甘薯潜隐病毒(SPLV)、黄瓜花叶病毒(CMV)、烟草花叶病毒(TMV)。  相似文献   
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