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Biomedical subjects

S Ganapathy

Publications and source records attributed to S Ganapathy.

48 records · Page 3Linked to original sources

Identification of the cause of separation (creaming) of lipid emulsions in intravenous infusion.

Over a 2-month period, white deposits were found in infusion sets delivering parenteral nutrition mixtures that included a lipid emulsion. When components of the infusion were mixed in the laboratory, separation (creaming) of the emulsion could be demonstrated, and this enabled us to predict the concentrations of the prescribed infusates that were likely to cream. Further investigations showed that creaming occurred when the lipid emulsion was mixed with heparin and calcium ions at concentrations above 1 U/ml and 1 mumol/ml, respectively.

Calcium↗

Efficiency of manual ventilation using the original EMO system.

The efficiency of the Oxford Inflating Bellows for intermittent positive pressure ventilation using a partially closed Heidbrink expiratory valve has been assessed by measuring the arterial carbon dioxide tension (PaCO2) after various intervals of IPPV on eight patients. It was found that satisfactory alveolar ventilation was achieved if a degree of hyperventilation was employed.

Carbon Dioxide↗

Multinuclear (27Al, 29Si, 47,49Ti) solid-state NMR of titanium substituted zeolite USY.

Multinuclear solid-state NMR spectroscopy, employing 29Si MAS,27Al MAS/3Q-MAS and (47,49)Ti wide-line experiments, has been used for the structural characterization of titanium substituted ultra-stable zeolite Y (Ti-USY). 27Al MAS experiments show the presence of aluminum in four (Al(IV)), five (Al(V)), and six (Al(VI)) coordination, whereas the multiplicity within Al(IV) and Al(VI) is revealed by 27Al 3Q-MAS experiments. Two different tetrahedral and octahedral Al environments are resolved and their isotropic chemical shifts (delta(CS)) and second-order quadrupole interaction parameters (P(Q)) have been determined by a graphical analysis of the 3Q-MAS spectra. The emergence of signal with higher intensity at -101 ppm in the 29Si MAS spectrum of Ti-USY samples indicates the possible occurrence of Q4(3Si,1Ti) type silicon environments due to titanium substitution in the faujasite framework. High-field (11.74T) operation, using a probehead specially designed to handle a large sample volume, has enabled the acquisition of 47,49Ti static spectra and identification of the titanium environment in the zeolite. The chemical shielding and electric field gradient tensors for the titanium environment in the zeolite have been determined by a computer simulation of the quadrupolar broadened static 47,49Ti NMR spectra.

Journal Article↗