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R Singhal

Publications and source records attributed to R Singhal.

23 records · Page 2Linked to original sources

Synthesis and characterization of fluoro-substituted polyaniline.

Poly(2-fluoroaniline) was prepared by both chemical and electrochemical polymerization in acidic medium. Characterization of poly(2-fluoroaniline) was accomplished experimentally using ultraviolet-visible, Fourier transform infrared, differential scanning calorimetry, thermal gravimetric analysis, and X-ray diffraction techniques, respectively. Scanning electron microscopy studies revealed globular morphology of chemically synthesized poly(2-fluoroaniline). The cyclic voltammetric studies revealed diffusion-controlled phenomenon in electrochemically synthesized poly(2-fluoroaniline).

Aniline Compounds↗

Preparation and characterization of poly-N-vinyl carbazole Langmuir-Blodgett films.

Langmuir monolayers of poly-N-vinyl carbazole (PNVK) were obtained by dispensing PNVK dissolved in tetrahydrofuran onto an air-water interface. Surface pressure-area isotherms of mixed monolayer of the PNVK were studied under different subphase conditions such as temperature and pH of the subphase. It was demonstrated that the monolayer of PNVK remained stable over a temperature range of 10-40 degrees C. The area per molecule of the solid phase was found to be 31 A2. These monolayers were transferred onto indium-tin-oxide-coated glass plates and characterized by spectroscopic and electrochemical techniques.

Air↗

Risk factors for duodenal ulcer in north India.

OBJECTIVES: The present study was designed to evalutate the association of various risk factors such as smoking, alcohol, NSAIDs, inadequate dietary intake of fibres and consumption of spicy foods with chronic duodenal ulcer using a case-control design and to establish the association of Helicobacter pylori and duodenal ulcer using different diagnostic techniques in Indian subjects. MATERIALS: A total of 16 consecutive patients with endoscopically proven duodenal ulcer (DU) constituted the test group while 160 subjects with non-ulcer dyspepsia (NUD) were recruited as controls. METHODS: All subjects were interviewed based on a standard questionnaire and underwent an upper gastrointestinal endsocopy wherein multiple biopsies were taken for rapid urease test (RUT), histology and culture for detection of H. pylori. The serum samples of all the subjects were tested for the presence of antibodies against H. pylori using ELISA. RESULTS: There were significantly greater number of smokers (80%) and alcoholics (58%) in the male population of DU group as compared to the controls (49% smokers & 15% alcoholics). Similar trend was seen in relation to history of chronic exposure to NSAIDs (29% in DU & 11% in NUD) and inadequate intake of fibre in diet (66% and 39% respectively). The overall prevalence of H. pylori was 82.5% in DU and 50.6% in NUD [p < 0.001]. CONCLUSIONS: In North Indian subjects, alcohol consumption, smoking, inadequate intake of fibre in diet and use of NSAIDs are the risk factors associated with doudenal ulcer disease. Further, infection with H. pylori is strongly associated with DU in the North Indian population.

Adult↗

Human pneumocystosis.

Pneumocystis is an atypical fungus causing pneumonia in immuno-compromised individuals. Though previously termed as Pneumocystis carinii, the recent taxonomy has considered human derived Pneumocystis to be a different species Pneumocystis jiroveci. The organism is the most common cause of opportunistic infections among patients with acquired immunodeficiency syndrome (AIDS) in developed countries. Incidence of Pneumocystis pneumonia or pneumocystosis in developing countries including India continues to be low. Microscopy of appropriate clinical samples has been the mainstay of diagnosis of pneumocystosis. Amplification techniques are now being evaluated for detection of P. jiroveci. This review attempts to give a recent update on P. jiroveci with special focus on epidemiology, taxonomy, current diagnostic modalities and recommended immuno-prophylaxis.

Humans↗