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81.
十大医疗仪器技术 总被引:1,自引:0,他引:1
胡宗泰 《上海生物医学工程》2007,28(1):40-49
医械工业的许多革新化进展,使得对病人的医护得到许多根本性的改善和提高,要列出其中最重要的十大应用领域和技术,不是件容易的事。美刊MD&MD根据目前情况,指出对病人医护、临床实践、产品开发以及整个医械工业具有深远影响的十大医疗仪器技术。这些技术以其新产品对人类的医疗保健作出了重大的贡献。 相似文献
82.
《Zoology (Jena, Germany)》2015,118(5):320-324
Crocodiles show oriented responses to water surface wave stimuli but up to now behavioral thresholds are missing. This study determines the behavioral thresholds of crocodilians to water surface waves. Nile crocodiles (Crocodylus niloticus) were conditioned to respond to single-frequency water surface wave stimuli (duration 1150 ms, frequency 15, 30, 40, 60 and 80 Hz), produced by blowing air onto the water surface. Our study shows that C. niloticus is highly sensitive to capillary water surface waves. Threshold values decreased with increasing frequency and ranged between 10.3 μm (15 Hz) and 0.5 μm (80 Hz) peak-to-peak wave amplitude. For the frequencies 15 Hz and 30 Hz the sensitivity of one spectacled caiman (Caiman crocodilus) to water surface waves was also tested. Threshold values were 12.8 μm (15 Hz) down to 1.76 μm (30 Hz), i.e. close to the threshold values of C. niloticus. The surface wave sensitivity of crocodiles is similar to the surface wave sensitivity of semi-aquatic insects and fishing spiders but does not match the sensitivity of surface-feeding fishes which is higher by one to two orders of magnitude. 相似文献
83.
以诸葛菜和油菜为材料,水培环境下设置4个不同的缺锌和碳酸氢根离子胁迫处理,分别为+Zn0(含Zn且不加HCO3-的处理组),+Zn10(含Zn且加10 mmol·L-1HCO3-的处理组),-Zn0(缺Zn且不加HCO3-的处理组)和-Zn10(缺Zn且加10 mmol·L-1HCO3-的处理组),利用离子色谱法分析了4个处理的两种植物幼苗器官(根、茎、叶)及根系分泌物中的有机酸特征。结果表明:(1)高浓度碳酸氢根离子处理显著增加了两种植物器官及根系分泌的有机酸总量,尤其是在缺锌和高浓度碳酸氢根离子双重胁迫下(-Zn10处理),诸葛菜器官和根系分泌的有机酸比油菜更敏感,草酸、柠檬酸和苹果酸是诸葛菜器官和根系分泌物中的优势酸,这三种有机酸的含量分别占其有机酸总量的75%及以上;(2)叶片是两种植物有机酸产生的主要器官,有机酸的含量和分配比例从地上部分(叶和茎)到地下部分(根)减少;(3)两种植物器官和根系分泌物中的有机酸变化趋势一致,叶片中有机酸主要来源于暗呼吸过程和光呼吸过程,其他器官和根系分泌物中的有机酸主要来源于暗呼吸过程;(4)诸葛菜对缺锌和高浓度碳酸氢根离子的适应能力强于油菜,为诸葛菜的喀斯特适生性和低锌和高浓度碳酸氢根离子环境(如喀斯特环境)的生态修复提供了理论依据。 相似文献
84.
为了阐明黄龙山白桦不同生境、不同径级、不同器官桦木醇与桦木酸含量,系统采集了陕北黄土高原黄龙山林场阳坡、阴坡、林缘、孤立木4种生境下的白桦不同径级植株的树皮、树枝和树叶样品,采用超声波辅助提取法提取样品,用高效液相色谱法测定了不同生境、不同径级白桦各器官桦木醇、桦木酸含量。结果表明:(1)不同生境下白桦各器官桦木醇、桦木酸含量均存在显著差异(P<0.05),白桦树皮中桦木醇与桦木酸含量、白桦树枝中桦木酸含量在4种生境下均表现为阴坡>孤立木>林缘>阳坡,白桦树叶中桦木醇与桦木酸含量及树枝中桦木醇含量均表现为阴坡>林缘>孤立木>阳坡,总体来看阴坡生境下白桦各器官桦木醇与桦木酸含量都是最高的。(2)在白桦各器官中,桦木醇、桦木酸含量均表现为树皮>树枝>树叶。(3)不同生境下白桦各器官桦木醇、桦木酸含量随着胸径的增大均先增大后减小,均在第Ⅱ径级即胸径10.1~20 cm达到最大。研究认为,阴坡生境有利于白桦各器官积累桦木醇、桦木酸;白桦各器官中桦木醇含量较高,桦木酸含量比较低,而以桦木酸为原料的生物制剂已进入临床应用阶段,因此,以桦木醇为原料制取桦木酸是解决桦木酸在天然植物中含量低、提取困难的有效途径;对白桦各器官的采收应注意把握时机,于白桦生长到胸径10.1~20 cm时为最佳采收期。 相似文献
85.
Ensembles of neuronal networks and sensory pathways participate in controlling the kinematic and dynamic parameters of animal movement necessary to achieve motor coordination. Determining the relative contribution of proprioceptive feedback is essential for understanding how animals sustain stable, coordinated locomotion in complex natural environments. Here, we focus on the role of chordotonal organs (COs), proprioceptors found in insect legs, in the spatial and temporal regulation of walking. We compare gait parameters of intact cockroaches (Periplaneta americana) and sensory-impaired ones, injected with pymetrozine, a chemical previously shown to abolish CO function in locusts. We verify that afferent CO activity in pymetrozine-treated cockroaches is inhibited, and analyze the effect of this sensory deprivation on inter-leg coordination. We find significant changes in tarsi placement and leg path trajectories after pymetrozine treatment. Leg touchdown accuracy, measured from relative tarsi positions of adjacent legs, is reduced in treated animals. Interestingly, despite poorer spatial coordination in both stance and swing, temporal properties of the gait remain largely the same as in the intact preparations, apart from changes in ipsilateral phase differences between front and middle legs. These findings provide insights into the role of COs in insect gait control and establish pymetrozine as a useful tool for further studies of insect locomotion. 相似文献
86.
滇龙胆不同部位裂环烯醚萜类物质含量比较分析 总被引:2,自引:0,他引:2
采用高效液相色谱法,对云南临沧云县滇龙胆不同部位龙胆苦苷、獐牙菜苦苷、当药苷含量进行分析.结果显示:(1)龙胆苦苷、獐牙菜苦苷、当药苷在滇龙胆根、茎、叶、花中均有分布;龙胆苦苷、獐牙菜苦苷在根部含量较高,分别为(35.88±5.89)mg/g和(1.35±0.33)mg/g;当药苷在花部含量最高,为(0.97±0.24)mg/g.(2)不同部位有效成分间具有显著(P<0.05)或极显著(P<0.01)的相关性.(3)相同海拔条件下,不同栽培方式下滇龙胆根部龙胆苦苷含量差异不显著(P>0.05),但茎部、叶部獐牙菜苦苷含量差异显著(P<0.05). 相似文献
87.
88.
Teleost intestinal immunology 总被引:1,自引:0,他引:1
Jan H.W.M. Rombout Luigi Abelli Simona Picchietti Giuseppe Scapigliati Viswanath Kiron 《Fish & shellfish immunology》2011,31(5):616-626
Teleosts clearly have a more diffuse gut associated lymphoid system, which is morphological and functional clearly different from the mammalian GALT. All immune cells necessary for a local immune response are abundantly present in the gut mucosa of the species studied and local immune responses can be monitored after intestinal immunization. Fish do not produce IgA, but a special mucosal IgM isotype seems to be secreted and may (partly) be the recently described IgZ/IgT. Fish produce a pIgR in their mucosal tissues but it is smaller (2 ILD) than the 4–5 ILD pIgR of higher vertebrates. Whether teleost pIgR is transcytosed and cleaved off in the same way needs further investigation, especially because a secretory component (SC) is only reported in one species. Teleosts also have high numbers of IEL, most of them are CD3-?+/CD8-α+ and have cytotoxic and/or regulatory function. Possibly many of these cells are TCRγδ cells and they may be involved in the oral tolerance induction observed in fish. Innate immune cells can be observed in the teleost gut from first feeding onwards, but B cells appear much later in mucosal compartments compared to systemic sites. Conspicuous is the very early presence of putative T cells or their precursors in the fish gut, which together with the rag-1 expression of intestinal lymphoid cells may be an indication for an extra-thymic development of certain T cells. Teleosts can develop enteritis in their antigen transporting second gut segment and epithelial cells, IEL and eosinophils/basophils seem to play a crucial role in this intestinal inflammation model. Teleost intestine can be exploited for oral vaccination strategies and probiotic immune stimulation. A variety of encapsulation methods, to protect vaccines against degradation in the foregut, are reported with promising results but in most cases they appear not to be cost effective yet. Microbiota in fish are clearly different from terrestrial animals. In the past decade a fast increasing number of papers is dedicated to the oral administration of a variety of probiotics that can have a strong health beneficial effect, but much more attention has to be paid to the immune mechanisms behind these effects. The recent development of gnotobiotic fish models may be very helpful to study the immune effects of microbiota and probiotics in teleosts. 相似文献
89.
The present paper provides a taxonomic revision of the genus Fecenia with emphasis on the characteristics of the pre-epigynes which are integrated for the first time into an identification key. As a result, one species is revalidated, Fecenia protensa Thorell, 1891, stat. n., and two new junior synonyms for Fecenia protensa are recognised: Fecenia sumatrana Kulczyński, 1908, syn. n. and Fecenia nicobarensis (Tikader, 1977), syn. n. New records are reported: Fecenia ochracea (Doleschall, 1859)from Malaysian Borneo, Fecenia macilenta (Simon, 1885) from Sumatra, Indonesia, Fecenia protensa from Thailand and Malaysia, Fecenia travancoria Pocock, 1899 from Sri Lanka and Thailand, and Fecenia cylindrata Thorell, 1895 from Thailand and Laos. Additional information on the biology of Fecenia is provided and the validity of characters for identifying Fecenia species is discussed. 相似文献
90.
空心莲子草营养器官结构与三萜皂苷动态积累的关系 总被引:1,自引:0,他引:1
王桂芹;徐如松;王锐 《植物研究》2011,31(6):686-691
采用组织化学定位、显微制片技术和三萜皂苷定量分析方法对空心莲子草营养器官结构与三萜皂苷类物质积累关系进行了研究。结果表明:空心莲子草宿根、根状茎、茎和叶中均有三萜皂苷物质的积累,叶和根状茎内含量十分丰富。在相同采收期内含量依次为:叶>根状茎>根>茎,叶中主要积累于栅栏组织细胞内。空心莲子草的根和根状茎横切面均属于异常结构,具有成同心环状排列的三生维管束。在宿根和根状茎的次生韧皮部、栓内层、三生韧皮部和结合组织内均有三萜皂苷的分布,三生结构在宿根和根状茎中占有主要地位,是三萜皂苷积累的主要场所。在不同采收期内叶、根状茎和根中三萜皂苷的积累趋势基本一致,均随生长期的增加而递增。空心莲子草茎的横切面由表皮、皮层、维管束和髓腔组成,仅部分皮层细胞和初生韧皮部内有三萜皂苷分布。 相似文献