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1.
The best known usage of members of the mustard group is as the basis for condiment, but some of the species are important as oil seeds. The leaves are widely used as a vegetable, especially in the Far East, while in temperate agriculture mustards are extensively used as green manures, cover crops, and fodder. Oilcake residues after expressing are used as fertilizers. 相似文献
2.
We present here the use of fluorescent methodologies for structural and functional studies of RNA in place of radioactivity. The methods are highly sensitive and quantitative with the use of an infrared fluorescence imaging system. IRD-700 and IRD-800 labels are used for fluorescence detection. Chemical probing methods are largely used for mapping RNA secondary structure and to monitor ligand interactions and conformational changes involving individual bases of RNA. The new fluorescent primer extension methodology allows simple and fast chemical probing of RNA with high sensitivity. IRD-700 and IRD-800 labeled primers can also be used to monitor protein-RNA interactions by fluorescent mobility shift assays. The speed and ease of these approaches are advantages over prior methods that used hazardous radioisotopes. Structural and biochemical investigations of RNA should benefit from the use of these fluorescent methodologies. 相似文献
3.
Jenkins MA 《Molecular biotechnology》2000,15(3):201-209
Capillary electrophoresis (CE) is an extremely sensitive technique, which has been used in the clinical laboratory for almost
10 yr. The components of CE instrumentation are described, as are injection modes, buffers, and effects of electroosmotic
flow. The modes of separation used in CE, namely, capillary zone electrophoresis, capillary isoelectric focusing, capillary
isotachophoresis, and micellar electrokinetic capillary chromatography, are explained. References for 26 different clinical
applications of CE are included, among them assays that are used routinely as well as niche assays for specialized applications
of CE. Verification of CE assays, current instrumentation, and future development of CE in the clinical laboratory are addressed. 相似文献
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A new set of signals for studying detectability of an X-ray imaging system is presented. The results obtained with these signals are intended to complement the NEQ results.The signals are generated from line spread profiles by progressively removing their lower frequency components and the resulting high frequency residues (HFRs) form the set of signals to be used in detectability studies. Detectability indexes for these HFRs are obtained using a non-prewhitening (NPW) observer and a series of edge images are used to obtain the HFRs, the covariance matrices required by the NPW model and the MTF and NPS used in NEQ calculations. The template used in the model is obtained by simulating the processes of blurring and sampling of the edge images. Comparison between detectability indexes for the HFRs and NEQ are carried out for different acquisition techniques using different beam qualities and doses.The relative sensitivity shown by detectability indexes using HFRs is higher than that of NEQ, especially at lower doses. Also, the different observers produce different results at high doses: while the ideal Bayesian observer used by NEQ distinguishes between beam qualities, the NPW used with the HFRs produces no differences between them.Delta functions used in HFR are the opposite of complex exponential functions in terms of their support in the spatial and frequency domains. Since NEQ can be interpreted as detectability of these complex exponential functions, detectability of HFRs is presented as a natural complement to NEQ in the performance assessment of an imaging system. 相似文献
6.
微囊化细胞培养过程的物质传递机理和细胞生长特性 总被引:1,自引:0,他引:1
综述了用于描述微囊化细胞培养过程中物质传递机理和细胞生长特性的数学模型,分析了这些模型在应用于微囊化细胞培养系统时所存在的问题,为建立能精确描述微囊化细胞培养过程中的物质传递机理和细胞生长特性的数学模型提供必要的参考,以有效推动微囊化技术在生物医学工程领域的应用。 相似文献
7.
The adhesion of bacteria to host tissue is the first step in pathogenesis. Similarly, bacterial adhesion to inanimate surfaces is the first step in formation of biofilms-a real problem in industrial processes and medical devices. Various agents capable of blocking the adhesion of bacteria to surfaces have been identified, such as probiotics, which are supposed to prevent the adhesion of pathogenic bacteria to the intestinal mucosa. Although measurement of bacterial adhesion is important itself, especially when agents used to prevent adhesion are developed, a relative small number of techniques can be used in the measurement of adhesion. These techniques are not well validated and there is lack of studies where those methods are compared to each other. Here we have compared different commonly used methods to measure adhesion of bacteria; radioactive labelling, fluorescence tagging, and staining of bacteria. The methods were used to measure the adhesion of Escherichia coli and Salmonella enterica serovar Typhimurium to intestinal mucus. Moreover, selected probiotic strains were used to study whether probiotics or the adhesion method used affected the results. As a result, we show that the best reproducibility and sensitivity were obtained using radioactive labelling. With other methods, the sensitivity was too low due to poorly adhering bacteria and low signal-to-background ratio. 相似文献
8.
The most important molecular techniques used in the diagnosis of Aspergillus spp. and typing of the most pathogen species of this genus are described and discussed. The former, are mainly based in PCR amplification of a concrete DNA fragment and posterior confirmation with Southern-blot; RAPD techniques and less frequently microsatellite markers analysis and DNA-DNA hybridization to a moderately repeated, inactive, retrotransposon-like DNA Afut1 are used in typing clinical isolates. 相似文献
9.
Abstract The absorption and emission spectra of biphenyl in cyclohexane are measured. Calculated Franck-Condon overlap integrals are used to simulate measured absorption and emission spectra of biphenyl in cyclohexane. The vibronic theory with the Born-Oppenheimer and Condon approximation is used. 相似文献
10.
Hollow fibres with a symmetrical pore structure as used in artifical kidneys are tested for other purposes. The modules are shown to be suitable for the processing of enzymes such as thermitase, penicillin acylase, uratoxidase, and phosphatase by means of ultrafiltration and diafiltration. These hollow fibre modules are compared with other modules used in laboratory or in small technical devices. Similar values and material transfer coefficients are calculated. 相似文献
11.
The genealogical method was used to study the family longevity in 220 individuals aged 80 and older in the Ukrainian SSR. The family longevity rate and total index are found to increase with the age of individuals examined. These indices in most cases are higher in men than in women and can be used as genetic markers to estimate the potential longevity. 相似文献
12.
Yuta Yasaka Minoru Tanaka 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1994,659(1-2)
The latest trends in the labeling of free carboxyl groups for high-performance liquid chromatography are reviewed. The labeling reagents for fluorescence detection are mainly discussed according to their reaction type (or functional group). Attention is also paid to the reagents used for ultraviolet detection and for enantiomeric separation. The reactivity and sensitivity of the reagents used for the labeling of carboxylic acids are described. 相似文献
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Multivariate measures of similarity and niche overlap 总被引:1,自引:0,他引:1
Niche overlap measures are used to assess the similarity in resource use by two species. Recently researchers have used niche overlap measures as summary measures and for making inferences, typically about competition for resources. The problem of estimating niche overlap when the niches are multivariate normal distributions with equal covariance matrices has previously been studied. In this work, the assumption of equal covariance matrices is relaxed. Two general measures of similarity are evaluated assuming general multivariate normal distributions. Commonly used measures of overlap are given as special cases of these two general measures. The question of bias in estimating these measures is discussed and shown to be a potential problem, especially when there are many redundant variables or if sample sizes are small. 相似文献
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J P Barach 《Journal of theoretical biology》1987,125(2):187-191
To illustrate the calculation methods used for biomagnetic fields we present a detailed calculation of the B-field from a spherical cell in an infinite ohmic bath. The calculation is done from three approaches and the results are used to clarify some misinterpretations that may seem to be biophysical problems but are, in fact, creatures of the formalism used. 相似文献
17.
Homing endonucleases are a class of site-specific DNA endonucleases encoded by open reading frames within introns and inteins. They initiate the mobility of their host element by recognizing intronless or inteinless alleles of their host gene and making a double-strand break. The homing endonucleases are notable for their long target sites and a tolerance for sequence polymorphisms in their substrates. The methods used to study homing endonucleases are similar to those used to study protein-DNA interactions in general. However, some variations and specialized techniques are useful in characterizing homing endonucleases and these methods are discussed. 相似文献
18.
Gongcheng is the second largest county in Guangxi with about 163000 Yao population. Periodic Markets are important places for trading of medicinal plants harvested by Gongcheng Yao villagers. The study aimed to look into the marked traded medicinal plants that are used by local people for curing various ailments. Ethnobotanical market survey methods, interviews, Participatory Action Research (PAR) and field visits were planned to elicit information on the uses of various medicinal plants. It was found that 71 plant species in the market which belong to 41 families are commonly used by local people for curing various diseases, all species are wild plants. A total of 133 records of medical uses in 52 herbal recipes for the treatment some common diseases. In most of the recipes recorded, digestion diseases, respiratory system diseases, infectious diseases,rheumatological diseases and surgery are used. The traditional knowledge about the number of medicinal plants available in that area and used by interviewees was positively correlated with the threats on medicinal plants in the wild habitats of the research area, which indicating that the diversity of wild medicinal plants and the associated traditional knowledge trends to disappear in the area. 相似文献
19.
Attempts to estimate human energy expenditure by use of doubly labeled water have produced three methods currently used for calculating carbon dioxide production from isotope disappearance data: 1) the two-point method, 2) the regression method, and 3) the integration method. An ideal data set was used to determine the error produced in the calculated energy expenditure for each method when specific variables were perturbed. The analysis indicates that some of the calculation methods are more susceptible to perturbations in certain variables than others. Results from an experiment on one adult human subject are used to illustrate the potential for error in actual data. Samples of second void urine, 24-h urine, and breath collected every other day for 21 days are used to calculate the average daily energy expenditure by three calculation methods. The difference between calculated energy expenditure and metabolizable energy on a weight-maintenance diet is used to estimate the error associated with the doubly labeled water method. 相似文献
20.
A group of moderately polar C21 steroids (3-5 oxygen functions) has been chromatographed in 9 solvent systems. Using the concept that standard deviation of the mean RF is an index of chromatographic resolution, and that coefficients of correlation between sets of RF data can be used to quantify the similarities of chromatographic systems, we have evaluated the resolving properties of the systems when used individually, and also when used in combinations of two, three and four. The discriminating powers of some of the most effective individual systems, and some of the sequences of systems which are most efficient, are shown graphically as chromatography trees. The relationship between the total effective standard deviation of a group of systems which are used in sequence and the probability that a pair of compounds will be separated by more than 0.10 RF is discussed. 相似文献