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Spherical silica nanoparticles (n-SiO2) with controllable size have been synthesized using tetraethoxysilane as starting material and ethanol as solvent by sol-gel method. Morphology and size of the particles was controlled through surfactants. Sorbitan monolaurate, sorbitain monopalmitate and sorbitain monostearate produced silica nanoparticles of varying sizes (80-150 nm), indicating the effect of chain length of the surfactant. Increase in chain length of non-ionic surfactant resulted in decreasing particle size of silica nanoparticles. Further, the size of silica particles was also controlled using NH3 as base catalyst. These silica nanoparticles were incorporated into cement paste and their role in accelerating the cementitious reactions was investigated. Addition of silica nanoparticles into cement paste improved the microstructure of the paste and calcium leaching is significantly reduced as n-SiO2 reacts with calcium hydroxide and form additional calciumsilicate-hydrate (C-S-H) gel. It was found that calcium hydroxide content in silica nanoparticles incorporated cement paste reduced ~89% at 1 day and up to ~60% at 28 days of hydration process. Synthesized silica particles and cement paste samples were characterized using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), infrared spectroscopy (IR) and thermogravimetric analysis (TGA).

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Sixty symptomatic confirmed human immunodeficiency virus (HIV)-positive adult patients, of both sexes, suspected of having a fungal infection were taken as a study population, and the clinicomycological profile was correlated with the immunological status of the patients with particular reference to CD4 counts. Relevant samples were collected and subjected to direct microscopy, fungal culture and serology. CD4 counts were determined by flow cytometry. Patients belonged to the age group of 17-65 years, with a male : female ratio of 4.8 : 1. Heterosexuality was the commonest mode of transmission. Candidiasis was the most common diagnosis (41.7 %), followed by cryptococcosis (10.0 %), and pneumocystinosis and aspergillosis (8.3 % each). Two cases of histoplasmosis were also diagnosed. A low mean CD4 count of ,200 cells ml Various fungal infections correlated well with the mean CD4 counts. It was difficult to correlate statistically WHO and CDC staging because of the small sample size. However, it was possible to assess to a limited extent the possibility of using clinical diagnosis to predict the status of progression of HIV infection in a resource-poor outpatient setting.

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