An antrochoanal polyp, a common clinical entity, with a rare presentation is being reported. A 12 year old boy was brought to Accident and Emergency department with an unusual sudden presentation of polypoidal mass filling the oral cavity up to his incisors as a result of which he could not swallow and speak. Prior to this episode he had no complaints of the disease. An emergency removal was planned and only during the operation could it be diagnosed as a antrochoanal polyp because of its pedicle in the lateral wall of the nose, which was confirmed by histopathological examination.
Colloidal Fe3O4 nanoparticles were synthesized using a gamma-radiolysis method in an aqueous solution containing iron chloride in presence of polyvinyl alcohol and isopropanol as colloidal stabilizer and hydroxyl radical scavenger, respectively. Gamma irradiation was carried out in a 60Co gamma source chamber at different absorbed doses. Increasing the radiation dose above a certain critical dose (100 kGy) leads to particle agglomeration enhancement, and this can influence the structure and crystallinity, and consequently the magnetic properties of the resultant particles. The optimal condition for formation of Fe3O4 nanoparticles with a uniform and narrow size distribution occurred at a dose of 100 kGy, as confirmed by X-ray diffractometry and transmission electron microscopy. A vibrating sample magnetometry study showed that, when radiation dose increased, the saturation and remanence magnetization decreased, whereas the coercivity and the remanence ratio increased. This magnetic behavior results from variations in crystallinity, surface effects, and particle size effects, which are all dependent on the radiation dose. In addition, Fourier transform infrared spectroscopy was performed to investigate the nature of the bonds formed between the polymer chains and the metal surface at different radiation doses.
A descriptive study was conducted on premarital HIV screening programme in Johor over a three year period. HIV screenings were done at government clinics and confirmed by accredited laboratories. As a result, 123 new HIV cases were detected (0.17%) from 74,210 respondents. In 2004, 24 cases (64.9%) advanced to marriage (n = 37) after they underwent counselling and six of them married among themselves. Positivity rate from this programme (0.17%) is higher than antenatal screening (0.05%). Despite the implementation of the premarital HIV screening programme, marriage application in Johor rose 2.8% in 2004 compared with 2002. This programme had partly contributed to public awareness against HIV and provides another option in early detection of the disease.
This review presents an introduction to the synthesis of metallic nanoparticles by radiation-induced method, especially gamma irradiation. This method offers some benefits over the conventional methods because it provides fully reduced and highly pure nanoparticles free from by-products or chemical reducing agents, and is capable of controlling the particle size and structure. The nucleation and growth mechanism of metallic nanoparticles are also discussed. The competition between nucleation and growth process in the formation of nanoparticles can determine the size of nanoparticles which is influenced by certain parameters such as the choice of solvents and stabilizer, the precursor to stabilizer ratio, pH during synthesis, and absorbed dose.