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Big Bang theory has played an important role to characterize radiation as the consequence of this enormous explosion(Smoot&Scott,2000).Most the present radiation is cosmic emissions as a sequence of many special interactions. Also, there are two other sources of radiation ,attributed to agriculture such as food and human made such as plastic(Lilley, 2001) .Thus, Radiation is well known as a beam of waves that have various of frequencies ,wave length, and energy. Also, radiation has the properties of waves in terms of reflection , refraction , and the sensitivity of radical elements, which contain mono proton and electron such as hydrogen. Generally, these waves are divided into two main categories depending on their amount of radiated energy. So, there is radiation with high frequency MHZ , classified as ionizing radiation because of its potential in ionizing the water molecules such as X-ray and Gamma ray . Also, there is another type of radiation which is named as non ionizing radiation due to their low emitted energy , resulted from its low frequency which is from  MHZ . As such radiation emanates low energy and long wavelength ,so, it will be an appropriate way to operate some wireless devices such as mobile phones.
Recent statistics have shown that mobile phones become one of the necessities of human being . International telecommunication union (2010) demonstrated that there are more than four billion of mobile phones in used around the world. These devices operate under electromagnetic spectrum through radio wave at microwave rang , which has negligible amount of energy because of its long wave length that results from low frequency. A mobile phone signal depends on two factors ,which are a portable antenna handset and a base station. Base stations are linked with typical land line and a source of microwave .In order to obtain high quality of coverage , the radiated power from a base station is inconstant and take a form of beams to feed the constant power of mobile phones(Hyland,2000) . Every mobile phone consists of an antenna to receive a signal from a base station , which is the source of emitted radiation, and a transmitter to trap this signal and encode it into sinusoidal wave ,which is a mono directional wave, then send this encoded signal by an antenna.
Therefore, users expose to amount of radiation during the process of receiving and sending a mobile phone signal .This amount of energy might play a significant role in changing the assemblage of human cells. However, these emitted radiations make no ionizing during the period of exposure because the number of electrons before and after exposure is the same,however, according to the thermal properties of this energy , there is a grain of truth in the claim that users of such devices might be affected biologically or cognitively. There is a possibility that mobile phone radiations could damage the barrier safety in the cells tissue then lead to some damages and transitions in cells DNA . Therefore, many scientists have taken this issue into account by conducting variety of experiments and researches but the results of these investigations are mixed, according to various point of views that rely on some theories and physical situations such as the consequences of thermal convection effects on the cells ,which might lead to some negative biological impacts upon the exposed cells, and the principle of non ionizing radiation that supports the claim of no effects of radiofrequency such as that from mobile phones.
The purpose of this paper is to examine some recent research on cellular phone radiation by comparing two different types of studies on this issue. First category of researches focus on thermal effects of microwave at different types of frequencies from (900MHZ , 1800MHZ,2.4MHZ, and 1.2MHZ) and, this paper will mention two types of mobile phone effects ,which are cognitive and biological effects. Also, this paper will investigate the possibility of electromagnetic field to affect children tissues. Then a new antenna process would be indicated in this research as the future development ,which is known as smart and Omni - directional.
Firstly, it is worthwhile to indicate the amount of energy which is absorbed by human tissue during the period of exposure ; this amount of electromagnetic energy is well known as specific absorption rate[SAR] , which could be calculated by multiplying the strength of the electron by the conductivity of human tissue and dividing the total on the density of human tissue(K.H.et al .,2004). So, according to this measurement , there is a certain amount of energy that human tissue must not exceed it. Every organ in human body has its own conductivity of energy intake , so, the allowable amount of [SAR] is different from an organ to other. For example, brain should not absorb higher than two watt/kg while the accepted dose in biological tissue such as eyes tissue is 0.08 watt/kg (Peter, Holger, and Martin ,2008). Also, there are various categories of mobile phone radiofrequency manufactories ,so, mobile phones emit different amount of energy. This emitted amount depends on some factors of cellular phones such as the location of their antennas and the density of the substances which are used to manufacture cellular phones. Despite the large number of attempts to make less radiated mobile phones, however, thermal effects of such various devices on users are capable of harming human cells (Igor Y et al ,2009).
In recent years , for example, there have been a large number of studies which suggest that the process of thermal convection of electromagnetic field ,which results from wireless devices, to human body heat the membranes of the cells where electrons orbit around. Then, a certain number of these electrons will be excited to upgrade from low level of energy to higher ones. So, this process of "electrons encouragement" maximize the amount of energy at exposed organs. Hossmann and Hermann (2003) demonstrated that human brain is the most vulnerable organ might be easily affected by radio frequency ,also, they found that electromagnetic wave could isolate the neurons inside the brain. Also, same result has been reported by Salford et al.,(2003) when a certain amount of mobile phones energy was given to laboratory rat , then ,it appeared that some rat brain cells were ready to be isolated by the flow of electrons inside the neurons. As a consequence of such isolation could have negative impacts on human immune because white blood cells will miss their targets during the exposure time. However, Tuschi et al., (2006) claimed that there is no significant danger of the radio frequency range on the immunity of human cells; this result came from an experiment, conducted among twenty two people who were asked to give thirty milliliters of blood then, exposed these samples of blood to radio signal during eight hours. However, it is important to note the limitation of this type of project , which was the deficiency of keeping the samples of blood clear of natural effects such as dioxide and nitrogen.(i bid).
In contrast to Weisbrot et al., (2003 p48) "sudden increase in temperature" among exposed cell leads to some changes in the power of hydrogen [PH],which defines the types of fluids whether acids or bases inside the proteins, so that these changes might cause instability and stress. Therefore, there will be some conversions in the components of proteins , in other word, hydrogenous acid ,which is the source of hydrogen ions , would lose some protons while base, which is the source of electrons , sending a certain number of electrons whereby there might be unbalance occurred between the components of atoms in the brain. However, Iihan et al.,(2004) claimed that low magnitude of energy does not have the potential of grabbing an electron from brain cells but the thermal feature of this energy could deteriorate the permeability of brain tissue in long term exposure then, carcinogenic substances would be easy to pass blood brain barrier. For example ,according to the equation of electromagnetic energy, which depends on the quantity of the wave frequency[Î½] and Blank constant [h], a short period of exposure to radio frequency at 1800 MHZ will emanate negligible amount of energy, which equal [1.192 x Joule].This insignificant amount of energy could play considerable damages among human cells if they expose to long term such as ten years or more because white blood cells will try to defend the body by losing a certain number of electrons ,so, this situation might cause some mutations, defined as electronic collision, among the nucleic acid inside the DNA. As Diem et al., (1995) found that there was an increase in alkaline (base) while human tissue expose to mobile phones frequency. As a result , there will be some urgent interactions to compensate the loss of electrons but these interactions accept the tumors that have a large number of electrons.
As it has been discussed above, long term of exposure to radio frequency might minimize the effectiveness of the human white blood cells and cause leucosis , which is the cancer of white blood cells. Evidently, Repacholi et al .(1997) (cited in Elder , 2003,p.S104) conducted an experiment by using mice rat and exposed it to the range of microwave from 900MHZ to 1800MHZ for two years then , there was a high possibility to be cancerous cells .Such experiment has one shortcoming, which was about the quantity of dose which the rat laboratory exposed to it. This dose at one of the experiment stages excessively given more than that emitted by mobile phones . So, many investigations followed Repacholi et al .,(1997) experiments, have found no significant change in the components of the exposed cells , for example, Utteridge et al (2003)( cited in Elder , 2003,p.S104) performed an experiment under the same Repacholi project conditions but with respect to the specific amount of cellular phones radiations(no more than 4W/kg of exposure) and found that there were a remote chance of tumors achievement , although, there were some loss of electrons inside the affected cells, also, the lack of blood flow was noticed especially in eye cells. These cells are the weakest cells in human body because of their low density to be able to provide the pupils with high density substance , which is the Melanin, so, . Stang et al.,(2001) pointed out some risks of radiofrequency among eye cells. For instance, if an eye exposed to 900MHZ , the density of this eye will reduce according to mass law : [density = mass/volume kg/m3] , so , during the period of exposure there will be an increase in the mass and the density of eye cells which lead to some inflation among the eye pupil.
In addition, the hazardous risks of radiofrequency are not limited to biological effects, but might accuse of some cognitive risks such as loss attention (Russo et al , 2006). Preece et al.,(1999)(cited in Russo et al. , 2006,p215)found some electronic activation among the brain because mobile phones operated in this study at 900 MHZ and was able to interact with water molecule within the short memory and take this form [H2O + -e=h+(-)h+o+(-)o].So, cells exerted force to transfer some information from short term memory to long term memory but while this transition there was loss of some information. Also, Besset et al.,(2005) conducted an experiment among fifty five people , exposed to radiofrequency for six weeks [2h/day] and asked to repeat fifteen worlds but participants had a difficulty in memorizing the words because an decrease in the reaction has been done while participants trying to remember the words, also, insomnia and sleeping disturbance have been noticed. It is not only Besset et al .,(2005) study has found the lack of reaction due to the energy of mobile phones but many result had been reported as a lack of cognitive reaction due to the mobile phones (Maier et al.,2004;Keetley et al.,2006)(cited in Unterlechner et al.,2008,p146 ).All these results were difficult to be justified since there were some complex reaction inside the neurons while the exposure period but what surely reported as the main reason of the impairment memory was the precipitate motion of electrons when they were attacked by radiofrequency. However, a common criticism of such investigations is the omitting of participants life style which affects the result explicitly ,for example, these previous studies did not take into account some important factors of judgment because some participants consumed caffeine more than regular rate(Unterlechner et al.,2008).Also, previous studies based on first and second generation of mobile phones which emit considerable amount of radiation whereas third generation (3G)of mobile phones emanate negligible amount of energy [0,1J] (i bid).However, the spread of using [3G], which has a large number of attractive properties that encourage children to use, raises a concern about the potential hazard of radiofrequency among children.
As it has been said above, even though there is no recognized effects of mobile phones radiation on children but they are prone to some damages in the neurons because these cells are under development, so, an external effects such as radiofrequency might make inertia to prevent the occurrence of electric collision (Van Rongen et al.,2004). For example, the circumference of the head of a child at one year old is 84% and from 93% to 95% at age of seven years old (Prader et al.,1989) (cited in Martens,2005, ps134).So, according to the ductility of new birth up to 7 years old , there is a high probability of mobile phone emissions to penetrate into the brain. On the other hand, Haarala et al.,(2005) claimed that there is no scientific evidence against mobile phones radiation among children ,although this study was on the base of previous studies such as Van Rogen et al ., 2004 study. So, the lack of grown cells in children brain were the mean reason to induce low quality of reaction while new birth were under observation. However. It is difficult to totally exculpate radiofrequency of biological function effects on children brain because according to specific absorption rate which is arise as long as the thickness of the brain is low(Christ & Kuster,2005).So, the absorbed amount of energy in children differs from adulthood. As microwave interact with water molecules , such interaction would be more convenient inside children tissues because they have considerable amount of water due to develop some important matters such as [myelinated and grey matters] (Van der Knapp & Volk,1995) (cited in Christ & Kuster,2005,ps35).
Taking these together ,as scientists have dwelled on the question of long term and short term of exposure among children who are in developing growth stage. So, it was important to solve the debatable issue of electromagnetic effects by adapting omni-directonal antennas ,which radiate and receive the same amount of energy at all dimensions[x,y,z] (Nakayama&Nakano,2000), also, this category of antenna is possible to named as non directional because there is no demand on any specific direction due to the equality of the frequencies within the whole directions. According to pressure law , which is the amount of force per area(p=f/x)N/m2, the total of pressure in omni directional antennas will be zero because the whole amount of energy is equal at all directions , for example, if there is an antenna emits [one J] in a direction , the other directions will radiate one[J] as well. Such type of antenna might reduce the frequency of mobile phones ,as a consequence the effects of mobile phones will decrease. However, Shin et al(2004) made the claim that non directional antennas could cause resonance amongst the metal dielectric because of the inertia , created when the stage of reflection between frequencies attempt to invalidate the propagation of radiation.
In conclusion , scientists have started to be concerned about human tissues with some apprehension of electromagnetic field before the advent of mobile phones .However, it is obvious that to date, there is no certainty whether mobile phones radiation has negative impacts on human biology. Also, scientific studies could not bring undoubtedly evidence to prove the negative impacts of mobile phones. However, biological effects such as damages in brain and some changes in DNA have been reported in many investigations. Such investigations have a certain number of limitations in their methods and material or in the conditions which these experiments were performed. Also , short term exposure has the same potential of heating living tissues as long term exposure but due to the gathering of emitted energy on human living tissue, there would be effects of the abundance of chemical interactions inside the cells then ,lead to cancerous cells. Also, the immunity among the neurons might have its proportion of instability and stress because of the motion of electrons that come from white blood cells to prevent the body from strange elements such as that come from mobile phones in the form of radio frequencies. In addition, there seems to be non thermal effects of mobile phone radiation in terms of impairment memory due to the reaction of the neurons against the sudden interactions which could affect also sleep pattern. Also, there were a certain number of scientific investigations on the possibility of children tissues because such tissue has a higher content of water that facilitates the energy absorption process. Finally, it was necessary to find solution to minimize the amount of radiated energy ,so, omni directional antenna was as a substitute to present antennas , however, this new antenna needs more investigations to avoid low quality of coverage while receiving or transmitting a call .