Biomedical subjects

S S Sekhon

Publications and source records attributed to S S Sekhon.

At least 19 recordsLinked to original sources

PubMed2005

Polymer electrolytes based on room temperature ionic liquid: 2,3-dimethyl-1-octylimidazolium triflate.

Room temperature ionic liquid (DMOImTf) based upon 2,3-dimethyl-1-octylimidazolium cation and trifluoromethanesulfonate or triflate (CF(3)SO(3))(-) anion has been synthesized and shows conductivity of 5.68 mS/cm and viscosity of 26.4 cP at 25 degrees C. Ion conducting polymer electrolytes based on polymers (poly(ethylene oxide) (PEO) and polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP)) and ionic liquid (DMOImTf) were prepared in film form by the casting technique. The conductivity of polymer electrolytes containing 0.5 M LiCF(3)SO(3) in PEO:DMOImTf taken in equal weight ratio increases with the addition of propylene carbonate (PC) while its mechanical stability improved by dispersing nanosize fumed silica. However, polymer electrolytes containing PVdF-HFP and ionic liquid show a high value of conductivity (10(-4)-10(-3) S/cm) alongwith better mechanical stability.

Journal Article↗

PubMed1981

Deleterious influence of hypothyroidism on evolving myocardial infarction in conscious dogs.

To study the influence of hypometabolism on evolving myocardial infarction in a model with intact autoregulation, we investigated 53 awake dogs after coronary artery occlusion. Severe hypothyroidism was induced by the intravenous administration of 131I. Animals were instrumented to obtain hemodynamic measurements, and regional myocardial blood flow was measured with radioactive microspheres. Infarct size was determined by the creatine kinase depletion method, and dysrhythmia analysis was performed from 24-h Holter monitor tapes in animals matched for infarct size. The microarchitecture of hypothyroid myocardium was determined by the electron microscope. Before coronary occlusion, mean systemic pressure in hypothyroid dogs was reduced by 14% and cardiac output reduced by 32%, with no change in left ventricular end-diastolic pressure, first derivative of left ventricular pressure rise, (dP/dt), or heart rate. After coronary occlusion, there was deterioration in hemodynamic measurements in both groups, with lower absolute levels of mean systemic blood pressure and cardiac output obtained in hypothyroid dogs. Hypothyroidism was detrimental to evolving infarction with a 36% increase in infarct size present in hypothyroid dogs (30 +/- 2%) compared to euthyroid controls (22 +/- 3%), P less than 0.05. Dysrhythmias were more severe in hypothyroid dogs. There were no changes in the relationship between regional myocardial blood flow and the extent of infarction after coronary occlusion. Abnormalities in microarchitecture were present in hypothyroid dog myocardium. Severe hypometabolism in this model was associated with alterations in hemodynamics, more severe dysrhythmias and changes in microarchitecture. The combined effect of these alterations resulted in an overall detrimental influence of hypothyroidism on evolving myocardial necrosis in this model.

Animals↗

PubMed1979

Electron microscopic studies of saprobic and parasitic forms of Coccidioides immitis.

During studies of both saprobic and parasitic cycles of Coccidioides immitis, we found that the hyphae contained septa with simple pores, Woronin bodies, pinocytotic vesicles and/or lomasomes. The alternating thallic arthroconidia were released by fracturing of the adjacent sterile cells. The endospores were formed by progressive cleavage of the spherules. The taxonomic classification of C. immitis still remains obscure.

Cell Division↗

PubMed1977

Sense organs on the antennal flagellum of psocids (Insecta, Psocoptera).

The sense organs on the antennal flagella of five species of winged psocids belonging to two families of Psocoptera, Psocidae and Leptopsocidae, have been examined, All agree in possessing tactile hairs, thick-walled chemoreceptors and long, porous chemoreceptors. Thin-walled chemoreceptors were identified in all species except Metylophorous novaescotiae. Coeloconic chemoreceptors were present in all species except Echmepteryx hageni. Campaniform sense organs were found only in Metylophorus novaescotiae and Psocus leidyi.

Animals↗

PubMed1975

The femoral chordotonal organs of a grasshopper, Orthoptera, Acrididae.

The fine structure of the prothoracic and mesothoracic femoral chordotonal organs of a grasshopper, Romalea microptera, is described. A single chordotonal organ may contain more than 300 sensory units. Each unit includes the cell bodies and dendrites of two neurons, together with sheath cells of several kinds. The cytoplasm of the sheath cells is packed with microtubules and filaments. These cells surround the cell bodies of the neurons and anchor them to the inner surface of the femoral wall. The dendrites from the two neurons are enclosed by a scolopale cell. At the distal end of this cell they traverse the extra-cellular space within the scolopale and their tips are fitted into cavities in the scolopale cap. The ciliary region of each dendrite is dilated for about one fourth of its total length. The cap is embedded in an elongate cap cell which is attached, in turn, to a ligament cell. The ligament cells are, themselves, attached to an apodeme that extends in from the tibia. When the tibia is flexed, the chordotonal organ is stretched and when it is extended, the organ is relaxed. It is postulated that the mass of the dilated region affects the character of the vibration that is induced when the dendrite is stretch or relaxed.

Animals↗

PubMed1974