Vol 7 No 4 (1978)

Articles

  • XML | PDF | downloads: 69 | views: 104 | pages: 168-179

    The study deals with noise problems associated with the use of air-turbine drills in dental practice. Noise level measurements were made on various types of dental handpieces, when operated free running and when used to cut tooth tissue. Hearing acuity tests were also undertaken in 12 randomly selected dental surgeons who have been using these drills for a number of years. The results indicate that although the danger to hearing from high speed drills is small, the possibility of hazardous effects-at least, for susceptible ears- is not excluded.

  • XML | PDF | downloads: 155 | views: 173 | pages: 168-179
    Infestation of soil and night-soil with the eggs or larvae of soil-transmitted helminthes is very important factor in the transmission of these infections. The effect of various temperatures and different chemicals on the development of larva inside the eggs of Ascaris, which is the most resistant eggs or larvae of helminthes, or destruction of developed larvae inside the eggs has been evaluated by infecting white mice or by direct observations. In eggs with developed larva, temperature of 600C for one hour kills all larvae while in lower temperature, 40% or more larvae are still alive. In a temperature of 600C for 15 and 20 minutes no larvae is found in the liver of mice. Of levamisole, thiabendazole, mebendazole, sodium-nitrite and calcium superphophate, thiabendazole and mebendazole have higher effect in destruction of eggs. In eggs with undeveloped larva, it was shown that in a temperature of 600C for 15 minutes or more, development of larva does not take place, while in lower temperature development of larva in some eggs takes place. In a temperature of 700C for 10 minutes no development of larva has been observed. Evaluation of the effect of levamisole, thiabendazole, mebendazole, urea, iodine and potassium dichromate has shown that mebendazole with a concentration of 1/100,000 or more inhibit the development of larvae. Other chemicals have some effects on the development of larvae. Results of previous investigations have shown that although many chemicals are effective in the laboratory conditions, they are not very effective when used in the field. Therefore, more studies on this subject in the field are necessary, in order to find application of this control method.
  • XML | PDF | downloads: 96 | views: 133 | pages: 196-206

    Finger Patterns and ridge-counts in a random sample of Iranian Muslims consisting of 100 males and 100 females are described. The most common finger patterns found were loops, having a frequency of 54.4% U.L., 3.4% R.L. in males and 51.2% U.L. and 4.8% R.L in females. The frequencies of arches and whorls in both sexes were 4% and 38.5% respectively. Bimanual and sex differences were indistinct. A Pattern type index of 11.85 and a pattern intensity index of 13.39 were found in both sexes combined. The mean total finger ridge-count observed is 166.54 in males and 160.93 in females. A significant sex difference of mean ridge-count was observed for digit numbers L3, L4, R2 and also for the total finger ridge-count with regard to bimanual difference for digit 2 in males and for digit 3 in females. The interpretation of the noted observations is discussed.

  • XML | PDF | downloads: 72 | views: 81 | pages: 207-212
    The existence of a high natural radiation area in the northern part of Iran (Ramsar) is proved. Ra 226 in soil is measured. The results are: minimum 23.5 pCi/g and maximum 999 pCi/g soil. Environmental radioactivity is from 0.1 to 5 mr/h.