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Desktop Publishing and Further Education
48
Monitor CHARLES F A BRYCE
commercial) are provided in the bibliography. A number of specific examples are included to illustrate the points made in the artice.
Department of Biological Sciences Napier Polytechnic Edinburgh, Scotland
[Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, UK]
Selvaratnam, M Problem-Solving -- a Model Approach. Education in Chemistry 27, 163-165 (1990)
Hu, J-Y, Senkbeil, E G and White, H B FluorometricAnalysis of Riboflavin. J Chem Education, 67, 803-804 (1990) The experience described in this article represents an inexpensive and versatile procedure for estimating the amount of riboflavin in an unknown solution and for determining the dissociation constant (Kd) of the vitamin-protein complex (riboflavin-binding protein, RfBP) without recourse to specialist equipment, with the exception of a fluorometer. The riboflavinbinding protein (RfBP) need not be highly purified and a simple protocol is provided for the isolation of crude RfBP from egg white. This involves separating the white from the yolk, removing bound riboflavin by dialysis against acid followed by dialysis against buffer and a centrifugation step. Alternatively, the RfBP can be obtained from commercial sources. In studying its fluorescence, the riboflavin sample is excited at 447 nm and its emission is measured at 530 nm. A calibration curve is determined for stock riboflavin and this is used in subsequent experiments to estimate unknown riboflavin solutions (pre-prepared, from vitamin tablets, from milk samples, etc). Using a known concentration of riboflavin, the Kd for RfBP is determined by titrating the riboflavin with aliquots of RfBP and measuring the fluorescence until this no longer decreases. An extension to this experiment is described in which the effect of a competitor (FMN or FAD) on riboflavin binding by RfBP can be studied. The results obtained compared very favourably with published data. [Department of Biochemistry, Salisbury State University, Salisbury, MD 21801, USA]
Leatherbarrow, R J Using Linear and Non-Linear Regression to Fit Biochemical Data. Trends in Biochemical Sciences 15, 455-
In this article the author considers the approach to solving quantitative numerical problems, the emphasis being on the systematic organisation of the thinking processes required for problem-solving into a generalised step-by-step procedure or model to help undergraduate students with this important activity. The algorthmic model proposed, which is an elaboration and refinement of an earlier one by Selvaratnam and Fraser, is described as a problem-solving direction map because it indicates the direction of thinking. Previously many of the general models for problem-solving have suggested starting wth the data supplied or with known information/knowledge and this, as the present author suggests, can lead to difficulties. The problem-solving direction map model starts with identifying the required quantity and 'thinking backwards' towards the supplied data. At each step the knowns and unknowns are identified and then the unknowns are further analysed until all quantities are known. This stepwise procedure encourages the student to focus on just one step at a time and so reduces the requirement for simultaneously handling many pieces of information. In this way crucial questions on how one decides which information is appropriate and how one combines information are dealt with. The author also considers 'hidden' information and implicit assumptions that can be derived from the information supplied. The direction map procedure is illustrated with a specific example dealing with density of gases. The model was developed for quantitative numerical problems and whilst it can be applied to other types of problem it is not suitable for 'open' problems such as research problems although it may be applied to component parts of such open problems. Difficulties arising from conceptual problems and/or lack of subject knowledge clearly cannot be addressed in any such generalised problemsolving model. [Department of Chemistry, University of Bophuthatswana. Bophuthatswana, South Africa]
458 (1990) Although regression analysis has widespread application in biochemistry, the author believes that the basis for the technique and the underlying assumptions are often poorly understood. The purpose of this well-written and interesting article is to describe the basics of both linear and non-linear regression, the role of weighting and the potential pitfalls of such analyses. The first issue to be addressed is the nature of the error, which can be either constant or proportional, which should reside exclusively in the Y-axis data and which can be accounted for by weighting of the data. The concept of correlation coefficients is described and the author outlines why he believes that this represents one of the most overworked and little understood statistics in the biochemical literature. Having set the scene he then considers the practice of creating linear transforms of non-linear equations and then performing linear regression to fit the transformed data, as is the case with, for example, the Seatchard plot and Lineweaver-Burk and Eadie-Hofstee plots, etc. The problem with this approach is that the rearrangements involved also rearrange the error distribution and so invalidate the assumptions behind the linear regression technique. Such problems can be circumvented by analysing the original data using non-linear regression by use of a computer, and suitable references to the associated theory and relevant software (commercial and nonBIOCHEMICAL
EDUCATION
19(1) 1991
Thomas, A and Davies, J Desktop Publishing and Further Education Journal of Further and Higher EducationQ4, 102-105 (1990) This very brief article may be of use to readers who are contemplating embarking on in-house desktop publishing but who have little background experience or knowledge. The authors identify the three key elements that make up desktop publishing as computer operation, editorial skills and design/ layout skills. Clearly, each of these must be addressed when contemplating the production of high quality presentations in an eye-catching, attractive and easily understandable form. If new equipment is to be purchased to support this activity, the authors recommend that all associated hardware and software be purchased and installed by one supplier rather than bought in a piecemeal fashion in order to avoid problems relating to communication, integration and/or handshaking. Recommended features for a laser printer are described as is the role for a lessexpensive dot-matrix printer and an optical scanner. Training of potential users is deemed an essential activity for the successful implementation of an in-house desktop publishing system. [Department of Education, University of Wales, Cathays Park, Cardiff CF1 1XL, UK]
Monitor CHARLES F A BRYCE
commercial) are provided in the bibliography. A number of specific examples are included to illustrate the points made in the artice.
Department of Biological Sciences Napier Polytechnic Edinburgh, Scotland
[Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, UK]
Selvaratnam, M Problem-Solving -- a Model Approach. Education in Chemistry 27, 163-165 (1990)
Hu, J-Y, Senkbeil, E G and White, H B FluorometricAnalysis of Riboflavin. J Chem Education, 67, 803-804 (1990) The experience described in this article represents an inexpensive and versatile procedure for estimating the amount of riboflavin in an unknown solution and for determining the dissociation constant (Kd) of the vitamin-protein complex (riboflavin-binding protein, RfBP) without recourse to specialist equipment, with the exception of a fluorometer. The riboflavinbinding protein (RfBP) need not be highly purified and a simple protocol is provided for the isolation of crude RfBP from egg white. This involves separating the white from the yolk, removing bound riboflavin by dialysis against acid followed by dialysis against buffer and a centrifugation step. Alternatively, the RfBP can be obtained from commercial sources. In studying its fluorescence, the riboflavin sample is excited at 447 nm and its emission is measured at 530 nm. A calibration curve is determined for stock riboflavin and this is used in subsequent experiments to estimate unknown riboflavin solutions (pre-prepared, from vitamin tablets, from milk samples, etc). Using a known concentration of riboflavin, the Kd for RfBP is determined by titrating the riboflavin with aliquots of RfBP and measuring the fluorescence until this no longer decreases. An extension to this experiment is described in which the effect of a competitor (FMN or FAD) on riboflavin binding by RfBP can be studied. The results obtained compared very favourably with published data. [Department of Biochemistry, Salisbury State University, Salisbury, MD 21801, USA]
Leatherbarrow, R J Using Linear and Non-Linear Regression to Fit Biochemical Data. Trends in Biochemical Sciences 15, 455-
In this article the author considers the approach to solving quantitative numerical problems, the emphasis being on the systematic organisation of the thinking processes required for problem-solving into a generalised step-by-step procedure or model to help undergraduate students with this important activity. The algorthmic model proposed, which is an elaboration and refinement of an earlier one by Selvaratnam and Fraser, is described as a problem-solving direction map because it indicates the direction of thinking. Previously many of the general models for problem-solving have suggested starting wth the data supplied or with known information/knowledge and this, as the present author suggests, can lead to difficulties. The problem-solving direction map model starts with identifying the required quantity and 'thinking backwards' towards the supplied data. At each step the knowns and unknowns are identified and then the unknowns are further analysed until all quantities are known. This stepwise procedure encourages the student to focus on just one step at a time and so reduces the requirement for simultaneously handling many pieces of information. In this way crucial questions on how one decides which information is appropriate and how one combines information are dealt with. The author also considers 'hidden' information and implicit assumptions that can be derived from the information supplied. The direction map procedure is illustrated with a specific example dealing with density of gases. The model was developed for quantitative numerical problems and whilst it can be applied to other types of problem it is not suitable for 'open' problems such as research problems although it may be applied to component parts of such open problems. Difficulties arising from conceptual problems and/or lack of subject knowledge clearly cannot be addressed in any such generalised problemsolving model. [Department of Chemistry, University of Bophuthatswana. Bophuthatswana, South Africa]
458 (1990) Although regression analysis has widespread application in biochemistry, the author believes that the basis for the technique and the underlying assumptions are often poorly understood. The purpose of this well-written and interesting article is to describe the basics of both linear and non-linear regression, the role of weighting and the potential pitfalls of such analyses. The first issue to be addressed is the nature of the error, which can be either constant or proportional, which should reside exclusively in the Y-axis data and which can be accounted for by weighting of the data. The concept of correlation coefficients is described and the author outlines why he believes that this represents one of the most overworked and little understood statistics in the biochemical literature. Having set the scene he then considers the practice of creating linear transforms of non-linear equations and then performing linear regression to fit the transformed data, as is the case with, for example, the Seatchard plot and Lineweaver-Burk and Eadie-Hofstee plots, etc. The problem with this approach is that the rearrangements involved also rearrange the error distribution and so invalidate the assumptions behind the linear regression technique. Such problems can be circumvented by analysing the original data using non-linear regression by use of a computer, and suitable references to the associated theory and relevant software (commercial and nonBIOCHEMICAL
EDUCATION
19(1) 1991
Thomas, A and Davies, J Desktop Publishing and Further Education Journal of Further and Higher EducationQ4, 102-105 (1990) This very brief article may be of use to readers who are contemplating embarking on in-house desktop publishing but who have little background experience or knowledge. The authors identify the three key elements that make up desktop publishing as computer operation, editorial skills and design/ layout skills. Clearly, each of these must be addressed when contemplating the production of high quality presentations in an eye-catching, attractive and easily understandable form. If new equipment is to be purchased to support this activity, the authors recommend that all associated hardware and software be purchased and installed by one supplier rather than bought in a piecemeal fashion in order to avoid problems relating to communication, integration and/or handshaking. Recommended features for a laser printer are described as is the role for a lessexpensive dot-matrix printer and an optical scanner. Training of potential users is deemed an essential activity for the successful implementation of an in-house desktop publishing system. [Department of Education, University of Wales, Cathays Park, Cardiff CF1 1XL, UK]