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1.
268例难治性下呼吸道感染的细菌学分析   总被引:5,自引:0,他引:5  
通过本组268 例难治性呼吸道感染病人标本培养结果分析,阳性246 例占91.8 % ,有154 例检出厌氧菌,占57 % ,104 例检出需氧菌,占39 % ,混合感染133 例,占50 % 。试验结果证实,厌氧菌感染在难治性下呼吸道感染病例中占了很大比例,这一结果为难治性下呼吸道感染的治疗提供了有价值的参考数据。  相似文献   

2.
沙冬青淀粉粒及其与叶绿体发育的关系   总被引:5,自引:0,他引:5  
沙冬青叶绿体中的淀粉粒一般为1-3个,主要有4种类型。第1种外周部分电子密度较高,中央部分较低,但每个部分的电子密度十分均匀。它们近似椭圆形,附近的类囊体形态正常,结构清晰。第2种电子密度由外向内逐渐变低,多为椭圆形,附近的类囊体较清晰。第3种外周部分的电子密度很高,中央部分不均匀,形状多种多样,附近的类囊体有的不清晰。第4种电子密度很低,十分均匀,形状不规则,附近的类囊体已经解体或正在解体。分析表明,淀粉的形态变化明显与叶绿体发育有关。  相似文献   

3.
白花败酱染色体的核型分析   总被引:3,自引:0,他引:3  
用去壁低渗染色体制片方法,对白花败酱(Patrinia villosa Juss)茎尖细胞染色体制片,研究其染色体组型.结果表明:白花败酱为二倍体、体细胞染色体数目为22;染色体组型公式为2n=2x=22=10m 4sm 4st 4t,第2、3、4、5、8号染色体为中间着丝点染色体,第6、11号染色体为近中着丝点染色体,第1、10号染色体为近端着丝点染色体,第7、9号染色体为端部着丝点染色体;染色体基数x=11,该染色体组内最长与最短染色体长度比值为3.037,臂比大于2:1的染色体共4条,占总数的36.4%,则白花败酱的核型类型为2B型.  相似文献   

4.
杉木人工林水量平衡和蒸散的研究   总被引:1,自引:0,他引:1       下载免费PDF全文
 本文根据我们严密设计的小集水区径流场连续6年的水文测定数据,进行了杉木人工林水量平衡和蒸散的研究。结果表明:集水区年平均降雨量1065.5mm, 在林冠作用面降雨量的分配中,林冠截留雨量264.6mm,截留率24.8%;穿透过林冠层的雨量799.82mm,树干径流量1.08mm,分别占降雨量的75.1%和0.1%。林内降水到达林地时,在枯枝落叶层这个作用面上净降水进行再分配,其中,地表径流量9.27mm,地下径流量203.00mm,总径流系数0.199。土壤蓄水量月变化较大,但年变化很小,占降雨量的1.2%。系统水量最大的输出是蒸散,每年以气态形式返回大气的水量866.03mm,占降雨量81.3%。在蒸散的水量中,林冠截留雨量的直接物理蒸发量为264.6mm,占总蒸散量的31.6%。  相似文献   

5.
Failure to Maintain Glycolysis in Anoxic Nerve Terminals   总被引:8,自引:6,他引:2  
Synaptosomal glycolysis is stimulated eight- to 10-fold when the respiratory chain is inhibited by cyanide or by anoxia. However, the stimulation is transient and after 15 min declines toward the preanoxic rate. The decline is not seen when Ca2+ is absent or when the respiratory chain is inhibited by rotenone. The decline in glycolysis is reversible, is not due to substrate exhaustion, and is the cause, rather than the effect, of lowered synaptosomal ATP/ADP ratios. The failure to maintain glycolysis when the terminal oxidase of the respiratory chain is inhibited may have relevance to the sensitivity of the brain to anoxic damage.  相似文献   

6.
山西省种子植物多样性分布格局与环境关系的研究   总被引:4,自引:0,他引:4  
采用除趋势对应分析(DCA)、典范对应分析(CCA)对山西省12个区域的种子植物多样性及区系地理成分的分析表明,全省种子植物多样性格局可分为3类:第1类为山西省西部和北部山地,热量相对较低,海拔较高,降水随海拔升高而增加,气候垂直变化明显,小生境类型较多,分类强度大,区系成分中以北温带、旧世界温带属占绝对优势。第2类为山西中部地区,地势相对较低,水热条件中等,北温带成分仍为优势种,但旧世界温带分布属和泛热带分布属的比例增加。第3类为山西南部和东南部山区,降水量相对较高,但温度也高,蒸发量大,属的区系成分中以北温带成分为优势,但第二优势成分为泛热带亚洲成分,与前2类地区相比,热带成分明显增加。  相似文献   

7.
本文从植物生长发育的机理发出,从理论推导出植物主茎传导能力与主茎长度、导管长度的关系式,导管越长,榈传导能力越大,香樟主茎长度大于18cm、枸树大于12cm时,传导能力随样品长度线笥变化;较知时,传导能力随样品长度的缩短迅速增加,出现短路现象。试验测定了香樟、枸树主茎水分长距离运输的传导能力分布,结果与理论预示的安全一致,表明理论分析是正确可靠的,这一规律具有普遍意义。  相似文献   

8.
糖、糖、“糖”——什么是糖?   总被引:1,自引:0,他引:1  
糖类是自然界中最常见的一类生物分子,但是糖类因不同的人群可以有三种不同的理解.一是科学上的糖类,二是生活中的糖类,三是作为甜味剂的"糖"类.因为甜味是一个生理上的感觉,凡能与甜味受体相互作用的均是甜味剂,其中有些是糖的"糖",也有不是糖的"糖".  相似文献   

9.
产生复干是银杏个体发育过程中一个普遍现象。本研究以临沂生生园全国最大复干银杏群落为对象,采用每木检尺的方式对园内复干银杏进行调查。结果显示,生生园内银杏共385株,雌株379株,占98.41%;平均树高20.9m,总胸径0.93m,母干胸径0.33m,冠径在5.0-15.0m范围内,枝下高6.3m;17株无复干,复干率为98.58%,每株复干数平均为4.6个,最大复干高为12.5m,胸径0.18m,复干与母干距离为0.61m,复干与母干夹角为10.5?;34株无萌蘖,萌蘖平均株数为38株,萌蘖高1.11m,萌蘖与母干最大距离0.73m。该片银杏林原桩有240年历史,现存复干银杏系从原桩萌发形成,树龄53年。本文对生生园复干银杏的起源、性别比例、复干与银杏适应性的关系等进行了探讨。  相似文献   

10.
The first comprehensive analysis of higher‐level phylogeny of the order Hymenoptera is presented. The analysis includes representatives of all extant superfamilies, scored for 392 morphological characters, and sequence data for four loci (18S, 28S, COI and EF‐1α). Including three outgroup taxa, 111 terminals were analyzed. Relationships within symphytans (sawflies) and Apocrita are mostly resolved. Well supported relationships include: Xyeloidea is monophyletic, Cephoidea is the sister group of Siricoidea + [Xiphydrioidea + (Orussoidea + Apocrita)]; Anaxyelidae is included in the Siricoidea, and together they are the sister group of Xiphydrioidea + (Orussoidea + Apocrita); Orussoidea is the sister group of Apocrita, Apocrita is monophyletic; Evanioidea is monophyletic; Aculeata is the sister group of Evanioidea; Proctotrupomorpha is monophyletic; Ichneumonoidea is the sister group of Proctotrupomorpha; Platygastroidea is sister group to Cynipoidea, and together they are sister group to the remaining Proctotrupomorpha; Proctotrupoidea s. str. is monophyletic; Mymarommatoidea is the sister group of Chalcidoidea; Mymarommatoidea + Chalcidoidea + Diaprioidea is monophyletic. Weakly supported relationships include: Stephanoidea is the sister group of the remaining Apocrita; Diaprioidea is monophyletic; Ceraphronoidea is the sister group of Megalyroidea, which together form the sister group of [Trigonaloidea (Aculeata + Evanioidea)]. Aside from paraphyly of Vespoidea within Aculeata, all currently recognized superfamilies are supported as monophyletic. The diapriid subfamily Ismarinae is raised to family status, Ismaridae stat. nov. © The Will Henning Society 2011.  相似文献   

11.
黍稷的名实考证及规范   总被引:3,自引:0,他引:3  
黍稷是起源于中国最古老的作物,糯者为黍,粳者为稷。长期以来对黍稷的称谓一直不能统一,特别是对稷的称谓在农史界一直争论不休,难以定论。本文从黍稷的起源演化过程、细胞学和遗传学的研究、黍稷是人类最早驯化的作物、我国甲骨文和古农书的记载等方面,论证了黍稷的起源早于粟。并以此为据,进一步辩证了稷不是粟,同时指出将黍稷称为软糜和硬糜、糜黍、糜子、黍子等不同称谓的不足之处,进而认为以黍稷作为规范称谓为好。  相似文献   

12.
The distribution of membrane current in three models of nerve, when a longitudinal, linearly increasing current is applied, is derived. For the simple core conductor model it is shown that, if the region over which such a current is applied is large compared to the space constant of the model, the membrane current in the mid-portion of the region is a constant, independent of the distance, the time following the application of the current, and the impedance of the membrane. The effect of nonlinear membrane electrical properties is discussed. It is further shown that these conclusions apply equally to the case in which the simple model is surrounded by another concentric sheath (the double cable model). In this case the impedance of the sheath does not influence the membrane current in the mid-polar region. Finally, it is shown that the form of the solution for the saltatory model, for this type of applied current, is identical with that for the simple model.  相似文献   

13.
The effect of inosine on the development of competence is dependent upon the time at which it is added to the competence medium. Competence is inhibited if inosine is added within 15 min after the development begins, but is stimulated if the addition is made at later times. Protein synthesis is stimulated by the addition of inosine, but the effect is quantitatively similar regardless of the time at which inosine is added.  相似文献   

14.
In this paper, a hyperelastic and thermodynamically consistent model for soft tissue is developed that is able to describe the change of the initial orientation of the collagen fibres. Full numerical implementation is considered as well. The collagen architecture is assumed to reorient driven by a specific thermodynamical force. The anisotropy is described by a strain energy function, which is decomposed into a part related to the matrix and a part related to the fibres. The initial fibre orientation is defined by a structural tensor, while the current orientation is described by a time-dependent structural tensor, which results from the initial one by a rotational transformation. The rotation tensor is obtained via an integration process of a rate tensor, which depends on an adequately defined thermodynamical force. The integration is achieved via an exponential map algorithm, where it is shown that the rotation is necessarily a two-parametric one. Efficiency of the proposed formulation is demonstrated using some numerical examples.  相似文献   

15.
A recommendation system is an imaginative resolution for managing the restrictions in e-commerce services with item details and user details. Also, it is used to determine the user preferences to recommend the items they expected to buy. Several conventional collaborative filtering techniques are devised in the recommender model, but it has some complexities. Hence, an innovative optimization-driven deep residual network is devised in this paper for a product recommendation system. Here, the product of images is used for extracting features where the Convolutional neural network (CNN) features are computed, and then it is given as input to the deep residual network aimed at product recommendation. The deep residual network is trained using developed Elephant Herding Feedback Artificial Optimization (EHFAO), which is obtained by integrating Elephant Herding optimization (EHO) into the Feedback Artificial Tree (FAT). Here, the item grouping is carried out on input data based on K-means clustering. After item grouping, Cosine similarity is used to perform matching of groups, where the best group is acquired among all the available groups. Extraction of list of visitors is done from the best group. Then, the list of items is obtained from the sequence of best visitor. Next, the corresponding binary sequence is obtained for the applicable sequence of visitor. From this sequence of best visitor, the recommended product is acquired. Then, the recommended product is subjected to the sentiment analysis for which the score is determined. Here, the sentiment analysis helps to decide whether the product is recommended or not recommended. If the score is positive, then the same product is recommended; otherwise, the new product is recommended. The proposed EHFAO-based deep residual network attained better performance in comparison to the other techniques with a maximal F-measure at 84.061%, 84.061% precision, 87.845% recall along with minimal Mean Squared Error (MSE) of 0.216.  相似文献   

16.
Phylogenetic relationships within Collembola were determined through the cladistic analysis of 131 morphological characters and 67 exemplar taxa representing the major families of the group, with special emphasis on Poduromorpha. The results show that the order Poduromorpha is monophyletic and the sister group to the remaining Collembola, with Entomobryomorpha monophyletic and the sister group to the clade Neelipleona + Symphypleona. In Entomobryomorpha, Actaletidae is the sister group of the remaining families. In Poduromorpha, Tullbergiinae is monophyletic as well as Onychiurinae and the group Tetrodontophorinae + Onychiurinae which is the sister group of the remaining Poduromorpha; Tetrodontophorinae is paraphyletic; Onychiuridae is polyphyletic; Isotogastruridae is not an intermediate between Poduromorpha and Entomobryomorpha, it is the sister group of Tullbergiinae; Odontellidae is monophyletic and the sister group to the clade Neanuridae + Brachystomellidae; in Neanuridae, Frieseinae and the group Pseudachorutinae + Morulinae + Neanurinae are monophyletic; Morulinae is the sister group of Neanurinae; Pseudachorutinae is paraphyletic; Hypogastruridae is polyphyletic; Podura aquatica (Poduridae) is not 'primitive', it clusters with the genera Xenylla and Paraxenylla in Hypogastruridae. On the basis of these relationships and the position of the aquatic species, the most parsimonious hypothesis is a terrestrial edaphic origin for the springtails.  相似文献   

17.
Pyrethrin, the active principle of pyrethrum powder, is insoluble in water but is soluble in, the body fluid of the cockroach. It has a selective action on nerve ganglia, and the destruction of their cells is responsible for the death of the insect. Whereas pyrethrum, when used -either in the powdered form or in a fluid state mixed with kerosene and introduced directly into the body cavity reaches the ganglion with the circulation, its mode of action when it acts through the spiracles is different. Kerosene-pyrethrum mixture when introduced into the tracheal trunks through the spiracles is quickly diffused into the haemocoele. When the dry powder is inserted into the trachea, its mode of action is analogous to a fluid preparation. As the conversion of pyrethrum from a dry into a fluid state is alone possible in the interior of the trachea, the natural conclusion is that a fluid analogous to the body fluid is present in the same situation. As soon as the pyrethrin is dissolved, it is quickly diffused into the haemocoele and thus reaches the nearest ganglion.  相似文献   

18.
In contrast to the epidermal growth factor (EGF) receptor, ErbB2 is known to remain at the plasma membrane after ligand binding and dimerization. However, why ErbB2 is not efficiently down-regulated has remained elusive. Basically, two possibilities exist: ErbB2 is internalization resistant or it is efficiently recycled after internalization. By a combination of confocal microscopy, immunogold labeling electron microscopy, and biochemical techniques we show that ErbB2 is preferentially associated with membrane protrusions. Moreover, it is efficiently excluded from clathrin-coated pits and is not seen in transferrin receptor-containing endosomes. This pattern is not changed after binding of EGF, heregulin, or herceptin. The exclusion from coated pits is so pronounced that it cannot just be explained by lack of an internalization signal. Although ErbB2 is a raft-associated protein, the localization of ErbB2 to protrusions is not a result of raft binding. Also, an intact actin cytoskeleton is not required for keeping ErbB2 away from coated pits. However, after efficient cross-linking, ErbB2 is removed from protrusions to occur on the bulk membrane, in coated pits, and in endosomes. These data show that ErbB2 is a remarkably internalization-resistant receptor and suggest that the mechanism underlying the firm association of ErbB2 with protrusions also is the reason for this resistance.  相似文献   

19.
Leghaemoglobin from the root nodules of kidney bean (Phaseolus vulgaris) reacts in alkaline glycine solutions as a glycine oxidase in a reaction that may also be regarded as a coupled oxidation. Leghaemoglobin is reduced to the ferrous form by glycinate, the oxygen complex is formed, and finally the haem is attacked to yield a green reaction product. Glycine is simultaneously oxidized to glyoxylate, and hydrogen peroxide is generated. The initial velocity of the formation of the green product is proportional to the concentrations of leghaemoglobin and glycine, and the optimum pH for the reaction is 10.2. The green product is not formed if carbon monoxide, azide of imidazole is bound to the haem, whereas oxidation of glycine to glyoxylate is not inhibited by azide and not essentially by carbon monoxide. Haem breakdown is activated by digestion of leghaemoglobin by carboxypeptidase, and partly inhibited by catalase and superoxide dismutase.  相似文献   

20.
路娟  陈非 《生物技术》1994,4(5):34-37
药敏药片经临床对金黄色葡萄球菌、大肠埃希氏菌、铜绿假单胞菌等235株考核.表明药片工艺研究先进,药片与培养基结合牢固,无断裂、崩解,不渗出颗粒,抑菌圈呈同心园扩散.边缘清楚。药物含量均匀,释放度好。药片抑菌差仅1~3mm;而纸片抑菌差为2~12mm。药片变黑系数CV为2.71~4.21;而纸片CV为3.82~14.36。表明纸片片间差大,药片精密度明显好于纸片。  相似文献   

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