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Biomedical subjects

S N Tandon

Publications and source records attributed to S N Tandon.

At least 37 records · Page 2Linked to original sources
PubMed1980

A versatile SAMI--a self contained digital heart beat counter.

The existing SAMI's (Socially acceptable monitoring instruments) as used for monitoring the variations in physiological parameters were considered to have certain drawbacks, such as trigger level adjustments and the need for frequent contact with the clinician/investigator. In the present system these drawbacks have been overcome by incorporating an automatic gain control into the circuitry and by using CMOS devices.

Computers↗
PubMed1980

Optimization of carrier frequency and duty cycle for pulse modulation of biological signals.

Digital modulation techniques are commonly used for the recording and transmission of biological signals. Hitherto, the choice of subcarrier frequency for recording or transmission of biological signals has been arbitary and this usually results in poor signal to noise ratio (SNR) due to the limited frequency characteristics of the system. In the present study the frequency characteristics of the system (first order approximation) has been taken to be that of a Butterworth filter. Computations based on this assumption show that for a given input signal there exists an optimum subcarrier frequency and a corresponding optimum duty cycle which would give maximum SNR of the system. For convenience, a nomogram has been prepared and it has been shown that for a given frequency response of the system, the nomogram could be used for selecting an optimum subcarrier frequency and a corresponding duty cycle. The theoretical formulations have been verified with experimental work.

Biomedical Engineering↗
PubMed1976

Bacterial contamination of skin used as a biological dressing. A potential hazard.

Bacterially contaminated skin used as a biological dressing on burn wounds can cause serious or even lethal infections, three examples of which are cited. Cadaver-skin allografts were frequently found to contain pathogenic bacteria. The frequency of infections due to the use of contaminated skin grafts on open wounds is unknown.

Autopsy↗
PubMed1976

Cerium nitrate: a new topical antiseptic for extensive burns.

The wounds of 60 burned patients were treated topically with cerium nitrate, which was applied either as a cream or in aqueous solution. Cerium nitrate has a potent antiseptic effect in human burn wounds, especially against gram negative bacteria and fungi. Pseudomonas aeruginosa was recovered from the wounds infrequently and never predominated. Fungi were practically never found. No patient treated with cerium developed a necrotizing wound infection. Analysis of the detailed bacteriological data indicated that, in contrast to previous results with use of the nitrate or sulfadiazine salts of silver, when gram negative species predominated, the flora tended to be predominantly gram positive when cerium was used. Therefore, some patients were treated simultaneously with cerium nitrate and silver sulfadiazine; this resulted in an even more efficient suppression of the wound flora than was observed previously with either cerium alone or silver salts alone; results with the simultaneous topical therapy in patients with injuries that previously were uniformly lethal were excellent. No toxicity attributable to the use of cerium was observed, although one instance of methemoglobinemia due to nitrate was documented. The adsorption of topically applied cerium essentially is nil. The use of cerium nitrate was associated with a nearly 50 percent reduction in the anticipated death rate. Cerium nitrate is a promising new topical antiseptic agent for the treatment of burns, particularly when it is used in combination with silver sulfadiazine.

Adolescent↗
PubMedDate not supplied

Parameters affecting the decay of some organophosphorus pesticides: a study by high-performance liquid chromatography.

An HPLC procedure has been developed to follow the decay of malathion and methylparathion under control conditions using an mu-Bondapak C18 column with a mixture of acetonitrile and water to mobile phase and an ultraviolet detector for detection. Studies have been conducted to monitor their degradation in water and soil at different temperatures, pH and organic content. The results show that the persistence of the pesticides decreases with increase in temperature, pH and organic content.

Acetonitriles↗
PubMedDate not supplied

Identification of metabolites of malathion in plant, water and soil by GC-MS.

Metabolism of malathion (O,O,-dimethyl S-[1,2-bis(ethoxy carbonyl)-ethyl]phosphorodithioate) has been studied in plants, water and soil. A number of products identified by gas chromatography-mass spectrometry (GC-MS), have been formed by de-esterification, oxidation and hydrolysis of malathion. Hydrolysis of the P-S and C-S bonds occur in alkaline pH 8.0 and acidic pH 5.5, respectively.

Brassica↗