Mesud Kahriman

Low Cost System Design to Measure and Analyze of Temperature Rise Caused by 2450 MHz RF Energy in Human Phantom Model

In recent years humans are more exposed to human-made fields than natural fields with developing technologies. Especially, widespread of wireless communication technologies in all areas of daily life and getting closer to sensitive organs like brain caused an increase in possible risks and worries about human health. In the study, a temperature measurement card has been designed and produced with the aim of observing the temperature rise at the phantom model generated by EM energy source. To that end, we present a study on the temperature rise of small dipole antenna (2450 MHz) that operate close to a user’s head (1, 4 and 7 cm). We found good correspondence between the temperature rise values evaluated in the phantom heads. According to the results of measure, expected temperature rise in the tissue exposed to RF energy may varies to the distance between radiated source and tissue.

Enhancing antibacterial effect of sodium hypochlorite by low electric current-assisted sonic agitation

Background This research focused on the effects of low electric current (μE)-assisted sonic agitation of sodium hypochlorite on Enterococcus faecalis infected human root dentin. Methods Extracted human canine roots were instrumented, sterilized, and experimentally contaminated with E. faecalis. After incubation for 21 days, the presence of the biofilm was confirmed by scanning electron microscopy (n = 3). Roots were randomly divided into seven groups according to decontamination procedures: G1: no treatment; G2: sterile saline; G3: 5.25% sodium hypochlorite; G4: passive ultrasonic irrigation; G5: EndoActivator (Dentsply Tulsa Dental Specialties, Tulsa, OK) agitation (EA); G6: μE agitation; and G7: μE-assisted sonic agitation. Fixed μE amperage and intensities were applied in G6 and G7. Following microbial sampling, bacterial colonies were counted using the direct plating method. Results Biofilm was not eradicated in any sample. The μE-assisted sonic agitation of sodium hypochlorite revealed the lowest cfu values (p<0.05), whereas there were no significant differences among the passive ultrasonic irrigation, EndoActivator and μE agitation alone (p>0.05). Conclusions Based on available evidence, the following conclusions were drawn: The μE-assisted sonic agitation increased the antibiofilm efficiency of sodium hypochlorite than passive ultrasonic irrigation and EndoActivator. The μE-assisted sonic agitation on 5.25% sodium hypochlorite is not capable to eradicate biofilms at 10mA energy level in 60s.

The Effects of Electromagnetic Fields with a Frequency of 2450 MHz on E. coli Bacteria

This study analyzes the effects of the devices that work at the frequency of 2450 MHz and that release electromagnetic waves on the growth of bacteria. E. Coli bacterial cells are used in this experiment. The bacterial cult is divided into two groups under sterilized conditions. For both groups, the temperature is held constant at 37 Co while the heating effect of the devices working at the frequency of 2450 MHz is minimized. Then, the bacterial cells in the experimental group are exposed to the electromagnetic waves released by the devices working at the frequency of 2450 MHz while the control group is incubated for 8 hours without any exposure to electromagnetic waves. At each hour, samples from the E. Coli bacteria that are exposed to electromagnetic waves and from the control group. After measuring the optical density of the samples, it is found that the electromagnetic waves released by the devices working at the frequency of 2450 MHz have negative effects on the growth of bacteria. So, the effects of the electromagnetic waves released by the devices working at the frequency of 2450 MHz on the growth of the bacteria might be thermal or stress-related. However, there is a need for further physiologic and morphologic studies on this issue. The studies on this issue should be conducted for the public health.

Creating head model by using 3-D pattern and evaluation of SAR mapping with numerical methods

In this study, it is aimed to evaluate SAR value occurred in human head in 1800 MHz. First, 3-D basic model of human head was designed by using HFSS (ANSOFT). So, some solutions were obtained from created model with putting source of 1800 MHz electric field in different orientations on 3-plane. This basic approach shows a close agreement with realistic ones.