A conceptual model of taste receptors

Of all the senses, that of taste is perhaps the hardest to define and quantify and elucidation of the underlying mechanisms is unrespondingly difficult. This article describes a conceptual model — at the molecular level — for the four basic taste modalities, using apparent specific volume as a fundamental parameter. It also considers possible practical applications.     

There’s something about Mary: The moral value of things <Emphasis Type="Italic">qua</Emphasis> information objects

Luciano Floridi argues that every existing entity is deserving of at least minimal moral respect in virtue of having intrinsic value qua information object. In this essay, I attempt a comprehensive assessment of this important view as well as the arguments Floridi offers in support of it. I conclude both that the arguments are insufficient and that the thesis itself is substantively implausible from the standpoint of ordinary intuitions.     

Applications of the stability-equation method to linear systems

This paper presents the applications of the stability-equation method to the analysis and design of linear systems. Control systems with multiple inputs and outputs are considered; the absolute stability and relative stability characteristics are analyzed. Stability conditions for control systems with a transport lag or a distributive lag are presented. Finally, the stability characteristics of a system with a distributive parameter are analyzed.     

Computer-aided map-making

Attempts to represent a spherical surface on a plane sheet, so that individual points stand in a proper relation to each other as regards both distance and direction, have occupied cartographers since the time of Ptolemy. Later, as maps were required not only as an aid to travel by land or navigation by sea an increasing amount of detail had to be incorporated in them. By traditional methods this was a difficult and time-consuming process, but very recently the use of the computer has pointed the way to the production of better maps more quickly and more cheaply.     

Faecal fat content in healthy adults by the ‘acid steatocrit method’

Malabsorption syndromes causing steatorrhoea are quite common in India. Estimation of faecal fat is an important non-invasive investigation, which provides vital information regarding the occurrence of malabsorption. The aim of this study was to estimate the fat excretion per day in stools of apparently healthy adults on an unrestricted diet in random spot stool samples using the Acid Steatocrit Method, which provides an alternate, simpler and yet reliable method of stool fat estimation. Several studies have proved the correlation of the acid steatocrit method with the conventional methods. In India, however, there has been no published data regarding the normal levels of fat in the stools, by the acid steatocrit method. We follow the normal range values, as set by the United States and the European countries, not having a range for the Indian population. Hence, we took up a preliminary study, to estimate stool fat in a section of normal and healthy Indian population. The result obtained after screening 600 healthy and normal adults, showed the mean of stool fat to be 8.72 gms/24 hours, which is much higher than that, defined by Western literature (7 gms/24 hours). This can be accounted for, by the cultural and ethnic variations in dietary and food habits. Further studies are required in the same direction, involving larger population groups, and in different malabsorptive conditions.     

Lipid peroxidation and antioxidant vitamins in urolithasis

The present, study was conducted to determine the level of malondialdehyde (MDA) as an index of free radial induced lipid peroxidation and antioxidant vitamins-vitamins A, vitamin C and vitamin E in 75 confirmed cases of urolithiasis. Significantly high level of MDA (p<0.001) with significantly low levels of vitamin E (p<0.001) and vitamin A (p<0.001) with no significant decrease in vitamin C (p>0.05) were observed in the plasma of urolithiasis cases as compared to normal controls. In conclusion, it appears that a role of lipid peroxidation and oxidative function exists in the pathogenesis of urolithiasis. But, the exact mechanism how this occurs remains to be elucidated.     

Medical knowledge discovery systems: data abstraction and performance measurement

Knowledge discovery systems can be traced back to their origin, artificial intelligence and expert systems, but use the modern technique of data mining for the knowledge discovery process. To that end, the technical community views data mining as one step in the knowledge discovery process, while the non-technical community seems to view it as encompassing all of the steps to knowledge discovery. In this exploratory study, we look at medical knowledge discovery systems (MKDSs) by first looking at three examples of expert systems to generate medical knowledge. We then expand on the use of data abstraction as a pre-processing step in the comprehensive task of medical knowledge discovery. Next, we look at how performance of a medical knowledge discovery system is measured. Finally, the conclusions point to a bright future for MKDSs, but an area that needs extensive development to reach its full potential.     

Effects of acidified water on fish

The acidification of water leads to disturbances in the water and ion metabolism of fish, including the acid-base balance. Many fish probably possess physiological mechanisms to eliminate these disturbances completely or in part. However successful they may be in the short term, such adaptation mechanisms nevertheless require additional energy, thus causing growth and reproduction to be retarded. Taking into account the high sensitivity of fish eggs and larvae to acidification, these phenomena are probably a major contributory factor to the decline of fish stocks in acidified water.     

Evaluation of A60 antibodies in pulmonary and neurotuberculosis

Humoral immune response against PPD derived A60 antigen was evaluated by quantification of serum A60 antibodies in thrity healthy adults not exposed to tuberculosis (Group 1), in twenty seven healthy adults exposed to tuberculosis patients i.e. staff working in wards of tuberculosis hospital for one to thirty years (group 2), in twenty five pulmonary tuberculosis patients admitted to the Institute for Chest Diseases, Hyderabad (Group 3) and in sixty neurotuberculosis patients admitted to Neurosurgery department of our institute (Group 4). Highly significant elevation of A60 antibodies was observed in pulmonary tuberculosis patients (p<0.01) compared to healthy adult groups. A significant elevation in serum was also observed in case of neurotuberculosis group compared to both healthy groups (p<0.01). A test on A60 antibodies in serum gavv a sensitivity of 100%, specificity of 96.6%, positive predictive value of 81% and negative predictive value of 100% for pulmonary tuberculosis, whereas a sensitivity of 58%, positive predictive value of 79% and negative predictive value of 75% were noted for neurotuberculosis patients. Results of A60 antibodies in ten cerebrospinal fluids (CSF) obtained from non tuberculosis patients and thirty two CSF from patients of neurotuberculosis did not show significant elevation of antibodies. However the ninetyfive percentile value of CSF A60 antibodies was higher in neurotuberculosis (7.4 U/ml) group compared to nontuberculous group (3.8 U/ml) and the test showed a good positive predictive value (83%), very low negative predictive value (25%) and low sensitivity (63%). Serum A60 antibody assay appears to be a good serological marker available today for pulmonary tuberculosis and a supportive marker for neurotuberculosis.