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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
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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
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短柄五加大,小孢子发生和雌,雄配子体发育的研究 总被引:6,自引:2,他引:4
短柄五加花药5枚,每个花药四个花粉囊。小孢子母细胞减数分裂时,胞质分裂为同时型,产生正四面体形的四分体。花药壁由表皮、药室内壁、中层和绒毡层四层细胞组成,其发育类型为双子叶型。腺质绒毡层,其细胞为二核。三细胞型花粉。子房5室,每室两个胚珠,上胚珠败育,下胚珠可育。下胚珠倒生,具单珠被,厚珠心。大孢子母细胞减数分裂形成线性排列的四个大孢子,雌配子体发育属蓼型。开花当天,花粉散开,雌配子体尚未成熟,处 相似文献
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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
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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
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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
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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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目的:了解老年教师骨质疏松病的情况,用超声骨密度仪对813例老年教师做跟骨超声振幅衰减值研究。方法:超声测量是一种新技术,利用不同密度的物体衰减值不同及穿过不同密度物体声速不同等特性对跟骨进行成像,并计算最具说明性区域的一系列数据。参数中BUA值为最主要的参数,三根等距离曲线的形态和宽度能直观分析出年龄与骨量变化的关系。结果:本文男性平均BUA为63.87dB/MHz,得出回归公式:体重=189.1417 0.2062BUA-0.0224SOS。女性平均BUA为58.9dB/MHz,各年龄分组的BUA值与参考值很接近,统计学显示无意义。结论:调查发现男性和女性的骨质不同,男性BUA骨峰值比女性高。BUA值与其体重有密切关系。在60岁以后(或绝经1-5年后)年龄增长与BUA值无明显关系,说明随着年龄的增加骨量减少很小或不减少。利用这种关系,假如BUA值突然下降则提示近期发生骨质疏松。 相似文献
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Michael J. Sharkey James M. Carpenter Lars Vilhelmsen John Heraty Johan Liljeblad Ashley P.G. Dowling Susanne Schulmeister Debra Murray Andrew R. Deans Fredrik Ronquist Lars Krogmann Ward C. Wheeler 《Cladistics : the international journal of the Willi Hennig Society》2012,28(1):80-112
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
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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
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Hossein Ehsani Mohammad Gudarzi 《Computer methods in biomechanics and biomedical engineering》2016,19(3):306-319
Computation of muscle force patterns that produce specified movements of muscle-actuated dynamic models is an important and challenging problem. This problem is an undetermined one, and then a proper optimization is required to calculate muscle forces. The purpose of this paper is to develop a general model for calculating all muscle activation and force patterns in an arbitrary human body movement. For this aim, the equations of a multibody system forward dynamics, which is considered for skeletal system of the human body model, is derived using Lagrange–Euler formulation. Next, muscle contraction dynamics is added to this model and forward dynamics of an arbitrary musculoskeletal system is obtained. For optimization purpose, the obtained model is used in computed muscle control algorithm, and a closed-loop system for tracking desired motions is derived. Finally, a popular sport exercise, biceps curl, is simulated by using this algorithm and the validity of the obtained results is evaluated via EMG signals. 相似文献
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In the temperature sensitive mutant of Drosophila, shibirets1 (shi), synaptic transmission in the dorsal longitudinal flight muscles (DLM) is normal at 19 degrees C, but is diminished progressively as the temperature is raised, and is blocked at 29 degrees C. The purpose of this paper is to determine whether this defect is located presynaptically, postsynaptically, or both. It is demonstrated here that the postsynaptic sensitivity to L-glutamate, the putative transmitter for this synapse, is not decreased at 29 degrees C. Furthermore, studies conducted with genetic mosaics of this mutant show that transmission is blocked when a mutant motor neuron synapses on a wild-type muscle fiber, but is not blocked when a wild-type motor neuron synapses on a mutant muscle fiber. Thus, the shi phenotype (temperature dependent transmission block) correlates with a shi motor neuron, not with a shi muscle fiber. The data, therefore, suggest that the defect is not postsynaptic, but presynaptic. 相似文献
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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
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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
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Igor Karšaj Carlo Sansour Jurica Sorić 《Biomechanics and modeling in mechanobiology》2009,8(5):359-370
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
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B S Kramer 《Molecular biotherapy》1990,2(3):132-136
In any formal statistical test of the null hypothesis (the statement that a population parameter is equal to a specific value), there are two possible types of error. Type 1 or alpha error has occurred if the investigator rejects the null hypothesis when it is true. For example, an experimental treatment is declared an advance over standard treatment when it is not. Type 2 or beta error has occurred if the null hypothesis is not rejected when it is false. In this case, the investigator concludes that the experimental treatment is no different than the standard when it actually is. The two types of error can be conceptualized, respectively, as the consumer's risk and the producer's risk. In many reports of clinical trial methodology, it is the producer's risk that is emphasized. It is understandable why producer's risk would be of concern to authors of clinical studies. There are, however, numerous potential sources of consumer's risk. It is the latter type of risk that is the primary subject of this report. 相似文献
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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