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1.
大分子吸附对低粘切变流场中红细胞取向的影响   总被引:10,自引:0,他引:10  
采用一种在低粘切变流场中,将红细胞变形指数DI,分解为转向指数与小变形指数的新型激光衍射法,比较了有不同分子量右旋糖酐或PVP处理的红细胞与正常对照组红细胞的(DI)or-γ曲线,发现上述两类曲线间存在明显差异,这一事实表明,这种新型激光衍射法有助于分子水平的微观流变学的研究。  相似文献   

2.
Low viscosity Ektacytometry and its validation tested by flow chamber.   总被引:2,自引:0,他引:2  
W Yao  Z Wen  Z Yan  D Sun  W Ka  L Xie  S Chien 《Journal of biomechanics》2001,34(11):1501-1509
The flow chamber was used to observe the orientation and small deformation of red blood cells (RBCs) in a shear flow of low viscosity. With the aid of computer software, the percentage of RBCs oriented to the C=0 orbit (OI)(F) and the degree of deformation (DI)(F) of such RBCs were calculated by processing the photographs. It was found that these parameters were highly correlated, respectively, to the orientation index (OI)(E) and the small deformation index (DI)(E) obtained by our low viscosity Ektacytometry (LVE). Thus, our flow chamber research has provided direct evidence to validate the use of this low viscosity Ektacytometry. Although there are relative merits for the flow chamber method using low viscosity medium, the LVE is more likely to be applied in clinic for its simplicity and convenience.  相似文献   

3.
A new technique is proposed to estimate the shear modulus (mu) and membrane surface viscosity (eta(m)) of red blood cell (RBC). Theoretical formulae for finding these two parameters are first derived based on the force balance on a RBC in a flow field of low viscosity. Different types of Ektacytometry are then used to measure relevant quantities. The obtained values (mu=6.1 x 10(-6)N/m, eta(m)=8.8 x10 (-7)Ns/m for normal RBC) are consistent with those previously found by micropipette technique and in AC electric field. The present technique is, however, much easier to operate and more advantageous in reflecting the average properties of a large quantity of RBCs, and it is much cheaper to be applied in clinical practice than any other method of measuring the two parameters. The sensitivity of the technique is demonstrated by testing RBCs treated with glutaraldehyde of different concentrations. This technique was demonstrated by the flow chamber.  相似文献   

4.
DNA index (DI) measurements and chromosomal analysis of 42 transitional cell carcinomas were done after mechanical and enzymatical disaggregation of the tumor specimens. The results obtained with these different disaggregation techniques were compared in the 33 cases (79%) that showed recognizable chromosomes. The enzymatically obtained cell suspensions could not be used for chromosomal analysis after short-term culture of 24 hours. In four cases, the DI after enzymatical treatment could not be estimated. In most cases, the DI obtained from the tumor cells was similar for both aggregation techniques, with the exception of four cases of enzymatically treated cell suspensions in which the DI could not be estimated. The average DI of the aneuploid tumors was 13% higher than the corresponding chromosome count. In 19% of the aneuploid tumors the proportion of aneuploid cells could not be measured after enzymatical treatment. In the remaining suspensions the proportion of diploid cells was higher after enzymatical disaggregation than after mechanical treatment. It is concluded that for flow cytometric and direct chromosomal analysis of bladder tumors, the mechanical disaggregation technique is most suitable.  相似文献   

5.
宋勇春  李晓林  冯固 《生态学报》2001,21(7):1130-1135
利用PVC分室培养装置研究了菌根际和菌丝际磷酸酶活性变化与土壤有机磷亏缺间的关系,结果表明,施用有机磷(植酸钠)能促进菌根根系侵染、提高土壤磷酸酶尤其是酸性磷酸酶的活性,使菌丝际范围变宽。菌丝际的存在使土壤有机磷亏缺范围加大,与非菌根植物相比,由于菌根真菌的作用,植物能更容易地从有机磷中获得磷营养以满足植物生长的需要,从而使其干物重和磷吸收量更高。  相似文献   

6.
The areal distribution of monthly mean values of the Discomfort Index (DI) in Israel is presented for key hours of the day for the summer half of the year. The DI as used in this study, is defined as the arithmetic average of the dry-bulb and wet-bulb temperature (°C), a value of 24 representing conditions at which half the people would feel uncomfortable. Data were collected from 95 meteorological stations situated in different parts of Israel. The raw data consisted of daily values of dry and wet-bulb temperatures for the hours 08:00, 14:00, and 20:00h for the years 1963–1972. Maximum values of the monthly mean DI in Israel generally occur in August. Geographically, the number of days of the year with DI greater than 24 ranges from 30 in the mountain regions, to 120 in the coastal plain, to 180 in the Jordan Valley, Dead Sea, and Arava regions. The dominant control of the observed distribution of DI in Israel appears to be topography. The DI is not a good measure of human discomfort for particularly hot and dry conditions, typical of those occurring during Sharav weather conditions. For such conditions, a new index was developed based on the difference between the dry-bulb and wet-bulb temperatures. The mean areal distributions of this difference index as well as that of the DI are presented for typical intense Sharav conditions. The new difference index appears to better represent discomfort during such conditions.Presented at the Eighth International Congress of Biometeorology, 9–14 September 1979, Shefayim, Israel.  相似文献   

7.
稀土元素对红豆杉细胞悬浮培养及紫杉醇合成的影响   总被引:3,自引:0,他引:3  
研究了在250mL摇瓶中,不同浓度的硝酸镧、硫酸铈铵、硝酸亚铈3种稀土化合物对细胞生长及紫杉醇分泌和释放的影响。结果表明,在培养初期加入稀土元素。3种不同稀土化合物对细胞生长影响强弱不同,但趋势相似,均使细胞的延迟期缩短。1ppm的Ce^4 促进细胞生长的效果最明显。细胞干重第17d达到10.9g/L。在指数期加入稀土元素。10ppmCe^3 刺激细胞生长的效果最明显,细胞干重最高值达到11.5g/dL,比对照高1.5g/L,而10ppm的La^3 抑制细胞的生长。经稀土元素处理后,细胞胞内和胞外紫杉醇含量都有大幅度的提高,其中以10ppmCe^3 处理,胞外紫杉醇释放率最大,达37.7%。  相似文献   

8.
 为探讨结肠癌细胞诱导分化的机制 ,采用抑制性消减杂交 (suppression subtractivehybridization,SSH)研究联合使用全反式维甲酸和 1 ,2 5-二羟维生素 D3诱导分化结肠癌 Lo Vo细胞前、后差异表达的基因 .经比较消减 c DNA文库的序列与基因库的序列 ,发现 :有 1个基因的序列与正常鳞状上皮细胞中的 1个表达序列标签 (expressed sequence tag,EST)高度同源 ,同时发现6个新 EST (基因库登录号为 AW2 66492、AW2 66493、AW2 66494、AW58751 8、AW58751 9和AW58752 0 ) .说明诱导分化涉及到多个基因的表达 ,结肠癌的发生是多基因综合作用的结果 .进一步研究这些基因和 EST的功能对于结肠癌的防治将有重要意义 .  相似文献   

9.
R Sennerstam  G Auer 《Cytometry》1990,11(2):292-299
Three human breast cancer cell lines (HTB-126, MDA-231, and HTB-122) with DNA index (DI) values between 1.26 and 1.72 were analysed together with a diploid mouse embryonal carcinoma cell line (PCC3) by a TV-video time-lapse technique (pedigree analysis). Cytochemical parameters (DNA and proteins) were studied in individual cells in a rapid scanning microspectrophotometer. Post-mitotic sister cell pairs were analysed after Feulgen-naphthol-yellow staining. The DI values of the cell lines were selected to reflect various well-known clinical ploidy entities differing in malignancy potentials. A mitotic disturbance of the partition of DNA and protein to daughter cells was found in particular in MDA-231 closest to the triploid DNA modal value (DI = 1.37). Duration of mitosis was considerably longer in the near triploid line compared to the other lines. The MDA-231 line was also least sensitive to suboptimal growth conditions. This report calls attention to a possible causality between mitotic error and intraclonal genotype and cell mass heterogeneity.  相似文献   

10.
高光谱植被指数与水稻叶面积指数的定量关系   总被引:14,自引:0,他引:14  
基于不同水稻品种、施氮水平和不同生育期下的大田试验,确立了水稻叶面积指数(LAI)与冠层光谱特征参数的定量关系.结果表明:水稻叶面积指数与部分高光谱植被指数存在良好的相关性,其中原始光谱组成的2波段差值指数(DI)形式相关性最好,其次为比值(RI)和归一化(NI)植被指数.相关最好的原始光谱植被指数是由近红外波段组成的差值指数DI(854,760),相关最好的一阶导数光谱植被指数是红光和近红外光组成的导数差值指数DI(D676, D778),但总体上导数光谱指数不如原始光谱指数与LAI关系密切.独立试验数据检验结果表明,以差值指数DI(854,760)为变量建立的水稻LAI监测模型具有较好的表现,可用于水稻LAI的估测.  相似文献   

11.
The systematic position and generic differentiation of the morphologically and geographically outstanding tribe Epithemateae (Gesneriaceae) was analyzed using the rbcL/atpB-spacer and trnL-F intron-spacer regions of chloroplast DNA. In our analysis Epithemateae forms a strongly supported monophyletic clade (bootstrap [BS] = 100%; jackknife [JK] = 100%; decay index [DI] = 12) and appears as sister to the rest of the paleotropical Gesneriaceae (= subfamily Cyrtandroideae). The paleotropical Gesneriaceae form a monophyletic group (BS = 88%; JK = 85%; DI = 3) that is sister to the neotropical Gesneriaceae (subfamily Gesnerioideae) plus Austral Gesneriaceae (subfamily Coronantheroideae) (BS = 99%; JK = 98%; DI = 10). Within Epithemateae Rhynchoglossum is sister to the remaining Epithemateae (BS = 97%; JK = 96%; DI = 12), in which Epithema is sister to a clade of two genera: Loxonia/Stauranthera (BS = 68%; JK = 64%; DI = 1), which form, together with Epithema, a sister clade (BS = 85%; JK = 83%; DI = 2) to Whytockia and Monophyllaea. While the support for Loxonia and Stauranthera is moderate, the relationship of Whytockia and Monophyllaea is very strongly supported (BS = 100%; JK = 100%; DI = 13). Apart from the somewhat surprising (but well-substantiated) isolated position of Rhynchoglossum, the results are in perfect accordance with the relationships worked out earlier on grounds of architectural and floral characters. Especially remarkable is the predicted coherence between the morphologically and geographically different genera Whytockia and Monophyllaea.  相似文献   

12.
Starting from the basic flux equation, it is possible to obtain an integral form relating the current componentsI i at an arbitrary pointr 2 to the distribution of mobilities and concentrationsc i, potential forces\(\bar \mu \), and chemical productivityp i without any restrictive assumptions such as constant mobilities, constant field, steady state, or electrical neutrality. The equation is
$$\begin{gathered} I_i (r_2 ) = G_i (r_2 )\left[ {\Delta \bar \mu _i - \int_{r_1 }^{r_2 } {z_i } FA\left( {p_i - dc_i /dt} \right)\left( {\frac{1}{{G_i (r)}}} \right)dr} \right]; \hfill \\ G_i (r) = 1/\int_{r_1 }^r {\frac{{dr}}{{z_i^2 F^2 c_i u_i }}.} \hfill \\ \end{gathered} $$  相似文献   

13.
The aim of the present study was to establish an upper limit of diploidy for microspectrophotometric (MSP) DNA measurements in sections of mesenchymal tissue analyzing DNA data of a large number of normal cell populations. The reliability of this upper limit of diploidy for discriminating between diploid and hyperploid bone sarcomas was tested by analyzing the same tumors by MSP in imprint preparations and flow cytometry (FCM). The median DNA value of control cells in tissue sections was given arbitrary value of DNA index (DI) 1.0, denoting the diploid DNA content. The proportion of cells with DNA values exceeding DI 1.25 (greater than DI 1.25) was determined for each normal cell population. The maximum percentage of cells with DNA values exceeding DI 1.25, encountered by analysis of 91 normal cell populations in tissue sections, was 31%. This percentage was set as an upper limit of diploidy. Hence, tumors with a higher percentage of cells greater than DI 1.25 were classified as hyperploid. When we applied this criterion, 31 of 36 sarcomas analyzed by MSP in tissue sections were hyperploid, which was in complete agreement with FCM and MSP in imprints of the same tumors. Apart from discriminating between diploid and hyperploid tumors, an attempt was made to determine peak DNA values of sarcomas analyzed in tissue sections. Peak DNA values, as defined by a minimum of 30% of the cells within a class width of DI 0.25, could be determined for 23 of 36 tumors. These peak DNA values correlated well with corresponding peaks obtained by FCM.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
We applied laser diffractometry and a linear image sensor to measurement of erythrocyte deformability to detect the light intensity pattern of the diffraction image. Deformability was evaluated as the deformability index (DI), calculated from the width and length of the diffraction pattern ellipse, estimated by the linear image sensor. With the erythrocytes under various shear stresses, the DI was linearly related to results by the geometric method (r = 0.996, p < 0.01). The coefficient of variance of DI at a shear stress of 236 dynes/cm2 was 0.2% (seven human blood samples), which was satisfactory for practical use. The DI was independent of the erythrocyte concentration in the range of 1.5 x 10(7)-5.0 x 10(7) cells/ml of suspension. Correlation between the DI and the logarithm of shear stress was linear in the range of 5 to 350 dynes/cm2 of shear stress in suspension media of different viscosities. Heat-treatment, which decreased membrane flexibility, caused parallel reduction of the DI plotted against the logarithm of shear stress. The method was sensitive and gave reproducible results. It may be useful for clinical applications.  相似文献   

15.
黄土区树种抗旱性指数的研究   总被引:11,自引:0,他引:11  
王孟本  李洪建 《植物研究》1999,19(3):341-346
根据PV曲线主要水分参数测定数据,进行了黄土区6个乔,灌木树种抗旱性季节变化趋势和树种间抗旱性指数排序分析,结果表明,树种抗旱性指数在生长季(5-10月)呈具有阶段降低的持续增大趋势,仅在雨季中后期(即树木年第24生长高峰期)略有减小,在年生长季土壤严重干旱阶段,树种的抗旱性指数大小排序为:海红〉河北杨〉柠条〉小叶杨〉北京杨〉刺槐。  相似文献   

16.
17.
The plant lectin Tetracarbidium conophorum agglutinin II binds to glycoproteins and glycopeptides in a structurally specific manner [Animashaun et al., (1994) Glycoconjugate J. 11, 299–303]. We have characterized the steady-state and time-resolved fluorescence of the tryptophan residues of this lectin. The fluorescence (λex = 295 nm, λem = 350 nm) decay is complex and can be described by four decay times with the following values: τ1 = 7.4nsec, α1 = 0.22; τ2 = 2.9 nsec, α2 = 0.25; τ3 = l.0 nsec, α3 = 0.34; τ4 = 0.2 nsec, α4 = 0.18. The addition of a biantennary glycopeptide $\begin{array}{*{20}c} {Gal\beta (1 \to 4)GlcNAc\beta (1 \to 2)Man\alpha (1 \to 6)\neg } \\ {Man\beta (1 \to 4)GlcNAC\beta (1 \to 4)GlcAc\beta (1 \to )\begin{array}{*{20}c} {Glu - Nh_2 } \\ | \\ {Asn} \\ | \\ {COOH} \\ \end{array} } \\ {Gal\beta (1 \to 4)GlcNAc\beta (1 \to 2)Man\alpha (1 \to 3)} \\ \end{array} $ to the lectin results in a quench and an 8 nm blue shift of the emission spectrum. The effect is saturable, and is described by an association constant of 1.8×105 M?1. The tryptophan fluorescence of Tetracarbidium conophorum agglutinin II may therefore be utilized to characterize thermodynamically the binding interactions between this lectin and complex glycoprotein.  相似文献   

18.
Measurement of amount of nitrogen fixed by a legume crop   总被引:9,自引:2,他引:9  
Summary The amount of nitrogen fixed by a legume crop can be calculated from the relationship % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGceaqabeaacaqGbb% GaaeyBaiaab+gacaqG1bGaaeOBaiaabshacaqGGaGaae4BaiaabAga% caqGGaGaaeOzaiaabMgacaqG4bGaaeyzaiaabsgacaqGGaGaaeOtai% aabccacaqG9aaabaGaaeypaiaabccadaqadaqaaiaaigdacqGHsisl% daWcaaqaaiGacggacaGG0bGaai4Baiaac2gacaGGGaGaaiyjaiaacc% cacaGGobGaaiylaiaacgdacaGG1aGaaiiiaiaacwgacaGG4bGaai4y% aiaacwgacaGGZbGaai4CaiaacccacaGGPbGaaiOBaiaacccacaGGSb% GaaiyzaiaacEgacaGG1bGaaiyBaiaacwgacaGGGaGaai4yaiaackha% caGGVbGaaiiCaaqaaiGacggacaGG0bGaai4Baiaac2gacaGGGaGaai% yjaiaacccacaGGobGaaiylaiaacgdacaGG1aGaaiiiaiaacwgacaGG% 4bGaai4yaiaacwgacaGGZbGaai4CaiaacccacaGGPbGaaiOBaiaacc% cacaqGYbGaaeyzaiaabAgacaqGLbGaaeOCaiaabwgacaqGUbGaae4y% aiaabwgacaGGGaGaai4yaiaackhacaGGVbGaaiiCaaaaaiaawIcaca% GLPaaacaqI4bGaaKiiaiaabshacaqGVbGaaeiDaiaabggacaqGSbGa% aeiiaiaab6eacaqGGaGaaeyAaiaab6gacaqGGaGaaeiBaiaabwgaca% qGNbGaaeyDaiaab2gacaqGLbGaaeiiaiaabogacaqGYbGaae4Baiaa% bchaaaaa!9A78!\[\begin{gathered} {\text{Amount of fixed N = }} \hfill \\ {\text{ = }}\left( {1 - \frac{{\operatorname{atom} \% N - 15 excess in legume crop}}{{\operatorname{atom} \% N - 15 excess in {\text{reference}} crop}}} \right)\user1{x }{\text{total N in legume crop}} \hfill \\ \end{gathered} \]when a suitable reference crop is chosen. The implications and interpretation of this method of measurement are described.  相似文献   

19.
Flow DNA analysis was performed on samples from 71 surgically removed lung cancers and from 145 patients undergoing bronchoscopy. Abnormal DNA stem lines, characterized by their DNA index (DI), were frequently observed in operated lung carcinomas (87%). Two or three abnormal DNA stem lines were discovered simultaneously in 10% of the samples. The mean DI of all abnormal tumor stem lines was lowest for rare tumor cell types and highest for adenocarcinomas. Intermediate mean DI values were found for epidermoid and small cell carcinomas, which were among the most proliferative tumors. The high rate of false negative results suggests poor diagnostic reliability of flow DNA analysis on bronchoscopic samples. However, the method appears to provide a promising objective tool capable of evaluating tumor behavior and prognosis.  相似文献   

20.
The second order nonlinear differential equation arises from a kinetics model of abrin binding in an Epstein-Barr virus-transformed lymphocyte culture. Some results on the dynamical behavior of this equation are given. These results are then discussed in relation to the known kinetics behavior of abrin in an EBV-lymphocyte cell culture.  相似文献   

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