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31.
福建武夷山甜槠群落能量的研究 总被引:43,自引:0,他引:43
在生物量、生产力研究基础上,对武夷山甜槠(Castanopsis eyrei(Cham p.ex Benth.) Tutch.)群落各组分的热值、群落能量现存量、能量年净固定量以及太阳能转化效率进行了研究。结果表明:(1)甜槠群落各组分样品的干重热值具有一定的差异,树皮热值最高,细根热值最低。(2)甜槠群落的能量现存量达780584.1 kJ·m - 2,其中地上部分为678913.8 kJ·m - 2,占总量的86.98% ;地下部分为101670.3 kJ·m - 2,占13.02% 。(3)甜槠群落的能量年净固定量(1992年)为26856.2 kJ·m - 2·a- 1,林地太阳光合有效辐射能的转化效率为1.296% 。 相似文献
32.
Kazushige Morimoto Eisuke Tsuda Ahmed Abdu Said Eriko Uchida Satoshi Hatakeyama Masatsugu Ueda Takao Hayakawa 《Glycoconjugate journal》1996,13(6):1013-1020
Ten erythropoietin (EPO) fractions differing in sialic acid content, ranging from 9.5 to 13.8 mol mol–1 of EPO, were obtained from baby hamster kidney cell-derived recombinant human EPO by Mono Q column chromatography. The mean pI values of the EPO fractions determined by IEF-gel electrophoresis systematically shifted from 4.11 to 3.31, coinciding with the sialic acid content, without a change in the constitution of asialo N-linked oligosaccharides of each fraction. Although a linear relationship between thein vivo bioactivity and the sialic acid content of the fractionated, samples was observed until 12.1 mol mol–1 of EPO, there was no further increase in their activity over 12.4 mol mol–1 of EPO. On the other hand, an inverse relationship between thein vitro bioactivity and sialic acid content of EPO was observed. Also, we showed that thein vivo bioactivity of some fractions with low sialic acid contents was increased after treatment with 2,6-sialyltransferase, but thein vivo bioactivity of the other fractions with high sialic acid contents was either decreased or not affected.Abbreviations EPO
erythropoietin
- rHuEPO
recombinant human erythropoietin
- hCG
human chorionic gonadotropin
- BHK
baby hamster kidney
- CHO
Chinese hamster ovary
- NeuAc
N-acetyl neuraminic acid
- Gal
galactose
- HRCs
hemolyser-resistant cells
- WST-1
2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium Na
- IEF
isoelectric focusing
- pI
isoelectric point 相似文献
33.
Estimation of the position and effect of a lethal factor locus on a molecular marker linkage map 总被引:3,自引:0,他引:3
R. Cheng A. Saito Y. Takano Y. Ukai 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(4):494-502
In the mapping of DNA markers the distortion of segregation of marker genotypes is often observed, which may be caused by a lethal factor acting in filial generations derived from distant crosses. A method is presented for estimating the recombination values between a lethal factor locus and neighboring molecular markers, and the relative viability or fertilization ability of gametes or zygotes affected by the lethal factor in an F2 population using the maximum likelihood method and the expectation conditional maximization (ECM) algorithm. Three selection models of gamete or zygote were considered, and the most likely one was determined by goodness of fit of the observed frequency of the phenotypes to the expected ones under the models. The method was applied to segregation data of molecular markers of an F2 population consisting of 144 individuals derived from a cross between an Indica and a Japonica rice variety. The presence of a lethal factor locus (L) located on chromosome III that caused partial gametic selection in both the male and female sides was suggested. The locus L was tightly linked to RFLP marker number 23 of the RFLP linkage map of Saito et al. (1991a), and the fertilization chance of a male or female gamete possessing the lethal factor was, on average, 41.5% of that of the normal gamete. 相似文献
34.
The evolution of phage lysis timing 总被引:17,自引:0,他引:17
Summary The effect of host quantity and host quality on the evolution of phage lysis timing is analysed using marginal value theorem of optimal foraging theory. Both factors have been shown to strongly influence the latent period. A high host density selects for short latent period, which is the same result as previous investigators have found. A good host quality also promotes a short latent period. However, elasticity analysis shows that these two factors exert their influences under different sets of conditions. When host density is low, the host density is more important in determining the length of latent period, whereas when host density is high, the host quality is more important. 相似文献
35.
精制蚕蛹油中碱液和过氧化值的控制 总被引:1,自引:0,他引:1
作者采用碱皂化的方法来达到精炼蚕蛹油的目的。实验表明,碱的浓度以10% ̄13%比较合适,超碱量必须视酸值大小,通过小样试验来确定。精制油的过氧化值与皂化后中性油的洗涤温度、洗涤次数及搅拌速度有密切关系,必须严格控制。 相似文献
36.
S. Green B. T. Dawson C. Goodman M. F. Carey 《European journal of applied physiology and occupational physiology》1994,69(6):550-556
The degree to which the y-intercept (Y-int) of the linear regression of maximal work output on exercise duration represented anaerobic capacity was determined in ten well-trained male cyclists [peak oxygen uptake (
= 69.8 (SD 4.2) ml · kg –1 · min –1). Each cyclist performed three exhausting cycle sessions on separate occasions; the mean exercise durations were 312, 243 and 141 s for the low (approximately 104%
, medium (approximately 108%
and high (approximately 113%
intensities respectively, and Y-int (kilojoules; joules per kilogram was derived from the regression of work output on exercise duration. The muscle anaerobic adenosine 5-triphosphate (ATP) yield (ATP) and anaerobic capacity (AC) were estimated from changes in metabolites in the vastus lateralis muscle and blood lactate concentration during the high intensity cycling session. The activities of glycogen phosphorylase, phosphofructokinase and citrate synthase, as well as muscle buffer value (in vitro ) were also determined. The Y-int (kilojoules) was positively correlated (P0.05) with AC (r=0.73), ATP (r=0.70) and in vitro (r=0.71); similar correlations (P0.05) were observed for Y-int (joules per kilogram). The Y-int was not correlated (P>0.05) with any enzyme activity. When the Y-int was transformed into oxygen equivalents [litres of oxygen equivalent (1 O2 Eq)] it was, on average, 0.92 1 O2 Eq lower than AC (P0.05); however, an alternative method of establishing the work-duration regression yielded a mean Y-int which was only 0.19 1 O2 Eq less than AC (P0.05). These findings support the validity of Y-int as a work estimate of anaerobic capacity in well-trained cyclists. 相似文献
37.
Pleural Fluid Adenosine Deaminase and Lymphocyte Proportion: Clinical Usefulness In the Diagnosis of Tuberculosis 总被引:1,自引:0,他引:1
Adenosine deaminase (ADA) and lymphocyte proportion are known to be independently elevated in tuberculous effusions, but are non-specific, and false positive results are frequent. to overcome this problem the combined use of both parameters was prospectively studied in 276 patients with pleural effusion seen at Porto Alegre, Brazil. Using a cut-off level of 40 U/l at 37°C (method of Giusti19 ) for ADA activity and lymphocyte proportion of more than 50%, the correct diagnosis of tuberculosis (sensitivity) was made in 90.7% (CI 87.3–94.1%) of 54 patients. A specificity of 97.7% (CI 95.9–99.5%) was recorded. Five false positive diagnoses of tuberculous effusion were made. Five false negative diagnoses were made: three cases with haematogenous tuberculous dissemination with low ADA levels, and two other patients with low lymphocyte proportion. the combined use of ADA activity determination and lymphocyte proportion is a highly efficient diagnostic strategy of low cost, that merits wider use. 相似文献
38.
HPLC and 1H-NMR methods for the quantitation of the (R)-enantiomer in (?)-(S)-timolol maleate were developed and validated. The HPLC method requires a 25 cm × 4.6 mm 5 μm Chiracel OD-H (cellulose tris-3,5-dimethylphenylcarbamate) column, a mobile phase of 0.2% (v/v) diethylamine and 4% (v/v) isopropanol in hexane at a flow rate of 1 ml/min and UV detection at 297 nm. A system suitability test was devised to verify the separation of the (R)- and (S)-enantiomers of timolol from other drug-related impurities. The NMR method requires the use of a high-field NMR spectrometer (>360 MHz) and a chiral solvating agent, (?)-(R)-2,2,2-trifluoro-1-(9-anthrylethanol) (R-TFAE). The limits of quantitation were 0.05% and 0.2% (m/m) for HPLC and NMR, respectively. The methods were applied to the determination of the (R)-enantiomer in eight lots of raw material. The results for the two methods were in very good agreement, with results ranging from 0.1 to 4.1% (m/m) by HPLC and none detected to 4.3% (m/m) by NMR. The USP method for specific rotation was found to be unsuitable for detecting the presence of low levels of the (R)-enantiomer in (?)-(S)-timolol maleate. © 1994 Wiley-Liss, Inc. 相似文献
39.
A new covalently-bonded, silica-based stationary phase, using as the chiral selector the 1-(3-aminopropyl) derivative of (+)-(5R,8S,10R)-terguride, has been developed to resolve optically active isomers by HPLC. Good resolution of structurally related racemic ergot alkaloids were obtained using water-methanol mixtures as the eluent. Analysis of the influence of the type and concentration of the organic modifier, and the pH of the buffer in the mobile phase allowed the enantioseparation of these compounds to be optimized. Determination of the optical purity of a lisuride-containig drug is reported. © 1994 Wiley-Liss, Inc. 相似文献
40.
The present paper illustrates the development of an advanced technique in optical resolution. Both of the amphetamine enantiomers can be obtained by a two-step distillation in nearly quantitative yield without any loss of the resolving agent. It is proved that the second-order interactions (H-bond) are sufficient for separation of enantiomers by distillation. © 1994 Wiley-Liss, Inc. 相似文献