1,720,968 research outputs found
PREPARATION OF THIN FILMS OF BIOMOLECULES BY THE ELECTROSPRAY METHOD
No full textProgram year: 1975/1976Digitized from print original stored in HDRThe preparation of thin uniform films of biomolecules has been a frequently encountered problem in chemical analysis techniques such as charged particle activation analysis, photoelectron spectroscopy, and with the recently developed technique of �������Cf plasma desorption mass spectrometry. Techniques such as vacuum evaporation from a heated filament and electrodeposition (1) which have been used to prepare thin films (<10 ��g/cm��) of inorganic compounds are generally not applicable for use with biomolecules (e.g., peptides, nucleotides, steroids, vitamins). The major problems are related to the thermal instability of these molecules and the requirement that any technique used to prepare a thin film must not alter the chemical identity of the molecule. Gentle methods such as deposition of a solution on a solid surface by solvent evaporation produce films that are aggregated and non-uniform. A method has been reported for the preparation of thin films using a specially designed nebulizer to produce a condensable finely dispersed mist of the solute without decomposition (2). However, films prepared by this method are also non-uniform, thick (10-1000 ��g/cm��) and require relatively large amounts of material.
With the development of the Cf-252 plasma desorption mass spectrometer (3), a better method was required for the rapid preparation of thin (<4 ��g/cm��), uniform targets of small quantities of fragile biomolecules over an area less than 0.75 cm��. The requirements of the method were that it had to retain the chemical identity of the sample, be non-fractionating when used with mixtures, non-contaminating, reproducible, and generally applicable to a wide range of molecules.
Carswell and Milstead developed a method which is called electrospraying for preparing thin radioactive sources (4), utilizing a phenomenon first observed by Zeleny (5). The method was modified (6,7,8) and has been used by Nawab and Mason to prepare highly uniform emulsions of water and oil (9). The purpose of this paper is to report our results on the adaptation of this method for preparing thin uniform films of biomolecules and to show that this method satisfactorily meets the criteria we had established as necessary for preparing samples for �������Cf plasma desorption mass spectrometry
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
PATTERN RECOGNITION TECHNIQUES FOR USE WITH �������Cf-PLASMA DESORPTION MASS SPECTROMETRY
No full textProgram year: 1975/1976Digitized from print original stored in HDRPattern recognition, as used in this paper, reflects a technique of machine data analysis. In this capacity the machine receives the raw data, processes it for the purpose of separating the important features from the background, and finally makes a decision which it bases on these features. For most purposes the decision is categorical (i.e. does compound A contain nitrogen?; is a particular peak indicative of an arginine-guanine complex, etc.). Since the author has an independent interest in the application of pattern recognition to the analysis of mass spectrometry data, this vehicle will be used to describe the techniques of applying pattern recognition in the laboratory. It should be kept in mind that these techniques may be applied to any data source that meets or���can be made to meet the machine data format
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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