[Effects of extremely low frequency [ELF] pulse and DC magnetic fields on the growth of E. coli]

Biological effects of extremely low frequency [ELF] pulsed electromagnetic fields have become attractive for research but still the mechanisms for this effects are not known. Moreover some reported biological effects of ELF are questionable due to poor reproducibility of the experiments. In this project ELF pulsed and DC magnetic fields were investigated on the growth rate of E. Coli DH5-alpha. In this experimental study, The cells were cultured in a lactose defined medium divided into two groups of 5 cuvetts and then were incubated. The experimental group was then placed in the field while the control group was left with no field. The applied fields were pulsed 6 msec apart and different frequency ranges from 10 to 45 Hz with the increment of 5 Hz and effective field range of 2 to 4 mT with an increment of 1mT and a constant field of 1mT through out the experiment. The growth rate was studied with turbidometery by spectrophotometers in the specified time interval. The growth rates in logarithmic phase and lag time were evaluated. The results indicated that pulse and DC combined magnetic fields increase the growth rate except in 15, 25 and 40 Hz frequencies. Lag time doesn't change in 15, 30 and 45 Hz frequencies. But in 20 and 40 Hz frequencies, magnetic field causes on increase and in 10, 25 and 45 Hz frequencies maximum decreases lag time. So in this frequency range, the magnetic field effect on the lag time has been repeated at an interval of 15 Hz. This research shows the existence of certain frequency windows for the resonance of the effects of the magnetic field on growth the cell

[ comparison study of articulation errors in cochlear implant children before 3 and after 4 years old]

Speech is the essential need of the social life. To acquire that, children highly rely on the normal senses and speech full environment. The normal auditory senseis the most important need. Early amplification intervention in children with hearing difficulties is advised. Cochlear implant technology provides an effective help for hearing-impaired children in recent decades. With regards to new and limited implantation services in Iran, the effects of operation age on speech and language of implanted children was not studied yet. The purpose of this study was to compare articulation errors in cochlear implanted children with different operation age. In this crosssectional study, ten cochlear implanted children before three and eleven after four years old were evaluated. The participants were without any anatomical, visual, and intelligence abnormality and 2.5-3 years was passed from their operation. Then, by using Picture Pho-netic Test [PPT], the articulation errors of individuals were extracted and for more evaluation of the er-rors and complete of PPT, we, also used their excited connected speech by presenting pictures. By applica_tion of t-test and using SPSS software, the data was analyzed. Data analysis indicated that, there was meaningful significant difference between substitute errors and whole errors in two gropes but there was not meaningful significant difference between de-stroyed errors in two gropes. The children who undergoing operation after 4 years old had severed articulation disorder than other grope. These issues indicated that the earlier operation of children will lead to improve the speech skills and reduced the articulation errors