Effect of gum Arabic on aminopyrine demethylation in rats

Summary Stimulation of aminopyrine demethylation induced in rats by oral or i.p. administration of phenobarbital was partially inhibited in animals receiving daily treatments of 2×200 mg/kg gum Arabic p.o.     

Aristotle's biological works as scientific literature

This contribution deals with the question of where and why in his biological writings Aristotle uses dialogical elements, examining which dialogical structures can be found and what the meaning of the dialogical structures is in respect of the argumentative strategies used in literature. This discursive style has to be seen in relation to the importance of the dialectical method which was practiced in the Platonic Academy and on which Aristotle reflected in his Topics. For Aristotle the dialectical method also becomes the method of the investigator researching for himself. But more than that one can see the reason for the dialogical structures in Aristotle's writings in his attempt to combine the way of acquiring knowledge with the way of presenting knowledge. It can thus be said that at the moment in which the dialectical procedure is translated into the medium of writing, a fact-oriented presentation is also an addressee-oriented representation. Nowadays we are more accustomed to a technical literature which, after completing the first step of the deduction of knowledge, presents the results in a systematic and hierarchical way in its literary representation; in such technical literature, normally an individual's thought process is not set out in writing. Admittedly, with the application of the dialectical method and with the attempt to set down one's own thought process in the medium of writing, other elements also come in.     

The endocranial parietal vascular traces in the hominid line]

The study of the grooves traced by the middle meningeal veins on the parietal bone or the endocast of Hominid fossils shows different patterns which correspond to each evolutive stage. Height types are characterised among the Hominids (Australopithecines, Archanthropines, Paleanthropines and Neanthropines): I, robust Australopithecine type; II, gracile Australopithecine type; III, earliest Pithecanthropine type; IV, evolved Pithecanthropine type; V, Preneandertal type; VI, neandertal type; VII, Neanthropine type; VIII, modern type.     

Life behind cell walls: paradigm lost, paradigm regained

This review of the living cell wall [1] and its protein components is in two parts. The first is anecdotal. A personal account spanning over 40 years research may perhaps be an antidote to one stereotypical view of scientists as detached and humorless. The second part deals with the meaning of function, particularly as it applies to hydroxyproline-rich glycoproteins. Function is a difficult word to define objectively. However, with help from such luminaries as Humpty Dumpty: "A word means what I want it to mean, neither more nor less," and Wittgenstein: "Giving examples of usage ... is the only way to talk about meaning," it is possible to construct a ziggurat representing increasingly complex levels of organization from molecular structure to ecology. Forty years ago I suggested that hydroxyproline-rich structural proteins played a key role in cell wall functioning. But because the bulk of the wall is carbohydrate, there has been an understandable resistance to paradigm change. Expansins, paradoxically, contribute greatly to this resistance because their modus operandi as cell-wall-loosening proteins is based on the idea that they break hydrogen bonds between polysaccharide chains allowing slippage. However, this view is not consistent with the recent discovery [Grobe et al. (1999) Eur. J. Biochem 263: 33-40] that β-expansins may be proteases, as it implies that the extensin network is not a straightjacket but a substrate for expansin in muro. Such a direct role for extensins in both negative and positive regulation of cell expansion and elongation may constitute a major morphogenetic mechanism operating at all levels of plant growth and development.     

A lost chapter in the pre-history of algebraic analysis: Whittaker on contact transformations

In the early 1930s W. O. Kermack and W. H. McCrea published three papers in which they attempted to prove a result of E. T. Whittaker on the solution of differential equations. In modern parlance, their key idea consisted in using quantized contact transformations over an algebra of differential operators. Although their papers do not seem to have had any impact, either then or at any later time, the same ideas were independently developed in the 1960–1980s in the framework of the theory of modules over rings of microdifferential operators. In this paper we describe the results of Kermack and McCrea and discuss possible reasons why such promising papers had no impact on the mathematics of the twentieth century.     

Forecasting domestic liquidity during a crisis: what works best?

The 1990s were a turbulent time for Latin American and Caribbean countries. During this period, the region suffered from no less than 16 banking crises. One the most important determinants of the severity of banking a crisis is commercial bank liquidity. Banking systems that are relatively liquid are better able to deal with the large deposit withdrawals which tend to accompany bank runs. This study provides an assessment of whether behavioural models, linear time series or nonlinear time series models are better able to account for liquidity dynamics during a crisis. Copyright © 2007 John Wiley & Sons, Ltd.     

Killing cancer by targeting genes that cancer cells have lost: allele-specific inhibition,a novel approach to the treatment of genetic disorders

Oligonucleotide-based drugs are now rapidly establishing themselves as an important tool in both research and treatment of genetic disorders. In the past many problems were encountered in using antisense oligonucleotides. Our expanding knowledge and new oligonucleotide chemistries are giving us the chance to treat serious genetic disorders such as cancer in novel, elegant and effective ways not previously possible. In addition, recent knowledge about RNA interference may add to these new approaches for disease treatment with oligonucleotide-based drugs. In this review we discuss one such novel therapeutic strategy against cancer called allele-specific inhibition (ASI). ASI is an approach where cancer cells are attacked at one of the few widely occurring and consistently weak points: the loss of large segments of DNA. Oligonucleotide-based drugs may provide the required selectivity for this therapeutic approach.     

Is it possible to find an econometric law that works well in explanation and prediction? The case of Australian money demand

Pratt and Schlaifer's (1984, 1988) research employed in efforts to produce laws in economics are considered and their use in predicting future data is described. Data for Australia are used to illustrate the approaches.