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1.
ABSTRACT

A novel scalable liposome preparation technique for pharmaceutical application is presented. Previous experiments have shown that the concept of continuous crossflow injection is a promising approach. For the characterization of the process, we focus on the influencing parameters like the lipid concentration, the injection hole diameter, the injection pressure, the buffer flow rate, and system performance. These experiments demonstrate that the injection hole diameter and the system performance do not influence the vesicle forming process and that a minimum of buffer flow rate is required to affect batch homogeneity. In contrast, strongly influencing parameters are lipid concentration in combination with increasing injection pressures. After exceeding the upper pressure limit of the linear range, where injection velocities remain constant, the vesicle batches are narrowly distributed, also when injecting higher lipid concentrations. Reproducibility and scalability data show similar results with respect to vesicle size and size distribution and demonstrate the stability and robustness of the novel continuous liposome preparation technique.  相似文献   

2.
根据14丘稻田稻茎毛眼水蝇幼虫调查资料.对其幼虫分布型进行了分析。结果表明;用I、CAm/m、Iσ四种聚集指标法测定,64.3%的田块呈随机分布.28.4%为均匀分布.7.3%为聚集分布。用Iwao平均拥挤度和Taylor幂法则测定.其田间分布型符合随机分布。用频次拟合法测验,50%的田块同时符合渡松、奈曼和负二项分布三种分布型;35.7%的田块同时符合2种分布型。根据该虫田间分布型的特点.制定了相应的序贯抽样技术。  相似文献   

3.
蜘蛛染色体单一胚胎压片观察   总被引:2,自引:0,他引:2  
曾庆韬  黄红 《蛛形学报》1998,7(1):39-41
利用单一胚胎压片法制备蜘蛛染色体取得了很好的结果。此法可以迅速确定蜘蛛染色体的性比,同时对于精巢特别小的蜘蛛染色体制备特别有用。所研究的蜘蛛染色体数目为:纵条蝇狮(Marpissa magister)2n=28()和26(),角园蛛(Araneus cornalus)2n=26()和24();2n=26和25();2n=24和33(),显示染色体多态型。  相似文献   

4.
ABSTRACT

Four types of vocalizations of the nocturnal lizard Gekko gecko (the ‘Tokay’) are described. A bark of intimidation, distress calls, a short not very intense call, apparently related to sexual inter-action, and a long, complex sequence. This ‘long sequence’ is considered to be a territorial proclamation which also functions as a mating-call. It has been analysed in detail with special emphasis on the intra-individual variations. The mean duration of this sequence is 22.3 s, the intensity is 70 dB at 1m and the maximum of energy is between 300 and 4000 Hz. This sequence is composed of three phases. The first one consists of several multipulse sounds called ‘rattles’, the second of bi-motifs which sound like a two syllable tok-kay, and the third, not always present, is a kind of ‘grumble’. The number of motifs and the occurrence of the third phase may vary but the duration of the motifs is relatively stable.  相似文献   

5.
6.
小菜蛾幼虫空间分布型和抽样技术的研究   总被引:1,自引:0,他引:1  
小菜蛾幼虫空间分布型测定结果表明:(1)频次分布检验为负二项分布;(2)素集度指标测定为聚集分布;(3)m^*-m的线性回归方程为m^*=0.0114 1.4608m,表明了属于最普通的聚集分布(负二项分布)。根据素集均数λ测定值结果,分析了聚集原因,在分布型研究的基础上探讨了Kuno种群序贯抽群的模型。  相似文献   

7.
再生稻二化螟幼虫的空间布型为负二项分布和聚集分布,其lwao的线性回归方程为m^*=0.0099 2.4753m,属负二项分布。根据聚集均数(λ)测定结果,分析了聚集原因,在分布型研究的基础上,探讨了资料代换模式,Kuno‘s种群序贯抽样模型和最适抽样数模型。  相似文献   

8.
用正弦波调制的光点刺激麻痹的清醒猫外膝体神经元感受野中心,当平均亮度改变时,瞬变细胞的时间频率调谐曲线的形状和敏感频率没有或很少变化,与此相应,这些细胞的自发发放也不随未调制的光照水平而改变。持续细胞的调谐曲线的调幅大体随对未调制光照的平均发放水平的升降而增大或减小,但敏感峰不变。衰减平均亮度1—2对数单位,可使多数呈双峰的调谐曲线的高调频峰消失,对产生此变化的原因,曾加以讨论。  相似文献   

9.
茶皂素生产工艺及其应用的研究进展   总被引:7,自引:0,他引:7  
本文综述了天然非离子表面活性剂茶皂素的生产工艺以及在实际中的应用 ,并就目前的生产和使用情况提出了一些看法和需要解决的问题。  相似文献   

10.
11.
We studied the taxonomic composition of flagellated nanoplankton in a temperate Canadian fjord, Saanich Inlet, for 1 year using electron microscopy. Most of the species that we identified were from the algal classes Prasinophyceae, Prymnesiophyceae, and Chrysophyceae and the protistan order Choanoflagellida. During summer months, we observed a diverse group of prymnesiophyte, prasinophyte, and chrysophyte species. In fall and winter, the number of species of prasinophyte and prymnesiophyte species in our samples decreased. At times, numerous chrysophyte species were present, and many of these were heterotrophic and typical of freshwater environments, presumably having been carried into the inlet by freshwater runoff. We suggest that during the winter months of 1991 a food web composed of dissolved and particulate organic debris, bacteria, algal cells, and choanoflagellates was an important feature of the plankton. We identified 71 species from 41 genera, and most of these have been reported for either other parts of the world ocean or freshwater environments, indicating that they have widespread distributions. Some species differed in cell and scale morphologies from those documented in the literature, and these distinctions are described. Thirty-two of these species were recorded for the first time from the coastal waters of the northeastern Pacific Ocean.  相似文献   

12.
蜘蛛染色体标本制备技术新探   总被引:1,自引:0,他引:1  
本文介绍了一种全新的制备蜘蛛染色体的方法,详细阐述了该方法的操作过程及技术要点。经研究发现灰斑新园蜘的染色体2n=44,大腹园蜘染色体2n=32。  相似文献   

13.
园林昆虫群落时间结构及动态研究   总被引:26,自引:2,他引:24  
调查了4种不同园林植物类型内昆虫群落在1年中的组成及数量变化,应用主分量分析方法及最优分割方法分析了昆虫群落在时间过程中的主导因素和时间格局。结果表明,构成复杂的植物类型内,昆虫群落构成亦复杂,在时间过程中,昆虫群落结构变化波动小,具有明显的主导因素和时间格局;在单纯的植物类型中,昆虫群落组成简单,随时间变化,群落剧烈波动,且主导因素及时间格局分化不明显。  相似文献   

14.
核仁组成区相关嗜银蛋白染色革新法   总被引:1,自引:0,他引:1  
核仁组成区相关嗜银蛋白(AgNOR)银染技术已广泛用以研究细胞生长活性,根据AgNOR数目多少来判定肿瘤的良恶性和对肿瘤进行鉴别诊断。然而AgNOR技术至今还存在背景非特异性银颗粒沉积问题而影响结果判定。本研究发现影响背景染色结果的主要因素是明胶的质量,采用Farmer’s液可以清除背景染色,运用微波炉染色不仅可以缩短染色时间而且可以减少银用量。  相似文献   

15.
16.
1. Flagellates are positively chemotactic to a certain concentration of dissolved oxygen which is lower than that in water saturated with oxygen under atmospheric partial pressure. Consequently, when a small aquatic animal is held motionless between cover-slip and slide in a suspension of flagellates in water saturated with oxygen, the flagellates are attracted to those parts of the animal which are absorbing oxygen. The relative sizes of the flagellate aggregations then show the relative activities of the different surfaces of the animal in absorbing oxygen. 2. Applying this method to the red Chironomus larva it was found that the animal respires by the whole body surface except by the head and the "ventral gills" and that the relative intensity of oxygen intake by the different parts of the body varies in different individuals and in the same individual at different times. 3. The absence of oxygen intake by the "ventral gills" was confirmed with the microspectroscope. In oxygen-free water all the hemoglobin of the blood becomes reduced. When an air bubble is now introduced so that it touches the "ventral gills" oxyhemoglobin first appears in the nearest body segment to the bubble, not in the "gills." 4. When a small aquatic animal is held motionless between cover-slip and slide in a solution of an indicator which changes color about the neutral point of water the relative extent of color change at different surfaces of the animal''s body indicates the relative amounts of carbon dioxide given off by these surfaces. 5. Using this method with the red Chironomus larva similar conclusions were reached for carbon dioxide output as for oxygen intake.  相似文献   

17.
介绍一种改进的研究气孔运动的方法   总被引:11,自引:0,他引:11  
本文介绍了以液氮现场固定叶样,扫描电镜直接观察(照相)记录气孔形态、分布、日变化等的方法。从给出的实例可以看到该法能成功地记录气孔在一天的动态变化情况。这种方法特别适合于研究叶表皮密被绒毛的植物。  相似文献   

18.
19.
本文介绍了一种获取灰岩中弱硅化腕足类化石的酸处理方法。以四川省布拖县浪珠乡万吨山剖面上奥陶统铁足菲克组近顶部的生屑灰岩为实验对象,通过准备样品、悬吊样品、配酸解液、酸解样品等实验流程,配合遮盖液(如二乙酸纤维素丙酮溶液)的使用,可获得保存精美的、弱硅化的腕足类实体化石,且该化石保存有主突起、铰齿和匙形台等重要的细小结构。相较于传统方法,该方法可获取硅化程度更低的壳相化石。该方法为灰岩中其他多门类弱硅化保存的化石之酸解分析提供了新思路和参考。  相似文献   

20.
Abstract:  The supposed polychaete annelid Protonympha salicifolia , from the Upper Devonian (Frasnian) of New York State, USA, is redescribed. P .  salicifolia has a bilateral and segmented body, but appears to have a 'mattress-like' construction with blade-like extensions along the margins. The affinities of P. salicifolia remain unresolved, but a proposed relationship to the annelids is unlikely. The preservation of the three known fossils, as mouldic imprints in sandstones, is strongly reminiscent of the circumstances associated with Ediacaran fossilization, and as such is an anomalous occurrence of such soft-part preservation in Phanerozoic sediments. Material associated with these enigmatic fossils has been referred to Palaeochaeta devonica , and also compared with the annelids. Such an assignment is also rejected. These fossils appear to be arthropodan, and are possibly myriapods. A supposed example of Protonympha (' P '.  marcellensis ) from the Middle Devonian of New York State is now excluded from this genus, and it may be a crustacean.  相似文献   

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