Radiation effect on DNA

DNA is double stranded large molecule with phosphoric acid, pentose sugar (2-deoxy-D-ribose) and organic bases. Phosphate moiety binds to the 5C of one end, the 3C of the neighbor pentose sugar to produce phosopho-diester linkage. The organic bases found in DNA are heterocyclic compounds containing nitrogen in their rings. So these are called nitrogenous bases. DNA normally contains adenine (A), guanine (G), thymine (T) and cytosine (C). Organic bases are linked with the pentose molecule to form nucleosides. This nucleoside binds with the phosphate group to form nucleotides.       

In DNA double helix number of pyrimidine bases is equal to that of purine bases. The two strands in a DNA are called complementary strands. The hydrogen bonds between A and T, and between C and G is known as complementary base pairing. There will be two hydrogen bonds between A and T, three hydrogen bonds between C and G. The chemical structure of DNA was shown in the figure1. DNA molecules are large molecules and packed into structures called chromosomes with the help of proteins (both histones and non-histones). Chromosomal aberrations may occur due to ionizing radiations. DNA is the primary target for cell damage from ionizing radiation compare to others which leads to mutations.

Mutations are sudden heritable changes. Agents which are responsible for inducing the mutations are called mutagens. Mutagens are of two types (physical mutagens and chemical mutagens). Physical mutagens are of types (non-ionizing and ionizing radiations). Alfa, beta and gamma radiations are ionizing radiations. They cause ionization of atoms in their path. So they are called ionizing radiations.
   
Alpha and beta radiations are particulate radiations, which consists of high energy atomic particles generated due to radioactive decay. Alpha rays are composed of alpha particles having two protons and neutrons devoid of electrons so they consist of double positive charge. Where as beta rays are high energy electrons produced by radioactive decay of 3H, 32P and 35S etc., and they are negatively charged. Gamma radiations are high energy radiations composed of photons. Gamma rays are non particulate rays. These are produced by decay of radioactive isotopes of 14C, 60C etc., Ionizing radiation remove the electron from its orbit around the nucleus of an atom.
   
Electron ejected from the atom A resulted in positive charge of the atom
Gamma rays produce ions in the above manner (Fig 2).  A high energy photon loses a part of its energy in removing electron from its orbit. The chemical effects of radiations are produced primarily due to ionization. The genetic effects of radiation result of their effects on DNA. The changes in DNA includes change in base (base substitution), loss of base (deletion and addition), disruption of hydrogen bond between nitrogen bases, single and double strand breaks and also cross linkage of proteins. Change in bases will produce missense, nonsense and frame-shift mutations. This will leads to gene mutations. Pyramidines are more sensitive to radiation when compare to purines.

The radiation damage to DNA occurs through two mechanisms (direct and indirect mechanisms). DNA damage caused by alpha, beta and gamma rays occurs when the displaced electron ionizes a water molecule, creating a free radical. As the free radical drifts, it may disrupt a DNA molecule. Direct damage is due to in which electron loss and electron gain within the DNA molecule which leads to instability of DNA molecule. Direct mechanism plays a more significant contribution to the DNA damage when compared to the indirect mechanism. Direct damage is predominant with alpha particles and indirect damage is predominant with gamma rays.             

Pospho di ester linkage break
The changes in the secondary structure of DNA caused by ionizing (gamma) radiations were studied by using circular dichroism and differential pulse polarography. Increase of the polarographic reducibility of DNA was observed on application of relatively low doses of radiation. Irradiation of DNA with low doses of gamma radiation induced local changes in angles and distances between the bases in the DNA double helix. Denatured DNA appeared after irradiating DNA with higher doses of ionizing radiation

Certain genes are responsible for rapid cell division which is called as oncogenes. Some other genes that slow down cell division and ultimately lead to cells death are called tumor suppressor genes. Cancers can be caused by DNA mutations (changes) that induce oncogenes or suppress tumor suppressor genes. First radiation-induced skin cancer reported in 1902. In 1920 bone cancer was observed among radium painters and in 1930 liver cancer was identified in Throtrast administration. However most DNA mutations related to breast cancer.

In view of the reaction mechanism proposed by Lewis, the reactions of metals and acids with certain species are very similar. In the Lewis mechanism, electron-deficient species such as metal cations, the hydrogen ion of acids and positively-charged species react with electron-rich species such as anions, hydroxide ions and molecules with free electrons to form new chemical bonds that even out the imbalanced electron distribution, in reactions like neutralization for acids and oxidation for metals (Whitten, 2004).
   
In the body, the production of acid for digestion is a well-regulated process, and the body has several organs and secretions that ensure that stomach acid levels do not get too high. There are possibly medications that could regulate the production of acid (probably antihistamines, according to someone I asked for opinion), but as these medications could upset the bodys proper functioning, neutralization of excess acid by the take-in of sodium bicarbonate seems to be better.
   
On the whole, the body can be thought of as one large chemistry set. The blood, for instance, is a complex system that exhibits fascinating chemistry, capable of delivering carbon dioxide out of the body via a chemical buffering system and also delivering oxygen to its parts via the binding of oxygen to an ion-molecule complex found in blood. Gastric acid is a solution composed primarily of hydrochloric acid. Urine is composed of organic urea and waste products dissolved in water.
   
The body is a well-regulated chemical system, and does not allow the presence of foreign chemical agents, which it rids itself of by metabolizing it into a form that it can easily dispose. Problem ensues when the product of metabolism is more toxic than the original compound. Taking in too much paracetamol, for instance, results in both liver failure and kidney failure, due to the liver being unable to neutralize the excess toxic product of paracetamol metabolism.

Five Basic Elements

The five elements in most ancient pagan cultures are the air, earth, water, fire and void. Each of the elements has a specific aspect associated with it. Fire can destroy and also build. It can also change something to another type. It has force therefore has to be contained. It is used to symbolize courage, strength zeal. In me, it signifies the hidden power that is within me that can be used in transforming any situation affecting me and also getting rid of any negativity about doubting the potential that is within me. The earth is used to symbolize the mother who sustains life through being generous with its resources in order to nurture all life on it. When I look around and see how much the earth bestows for us, am just inspired to share my resources with the less fortunate.

Water in most cultures signifies clarity, healing, purity and psychisim. In me, it signals that there is the ability within me of remaining true to my principles. Air is given the attribute of movement, refreshment and energy in most cultures. These attributes add in me the zeal to always step out of my comfort zone and seek better areas of improving my situation. The most vital of all these elements is balance. All these elements when they are in balance, their behavior can be established but when they are not, their behavior becomes unpredictable (Kotelnikov, 2008). 

When we fail to plan our lives in a balanced manner and overindulge in areas that do not add value to our life, our lives can become uncontrollable and unpredictable just like these five elements. All these elements interact between themselves in a series of cycles that are either destructive or productive. We should learn to embrace the fact that there will be destructive cycles and productive ones in this life in order to be well prepared to handle of all them well when they happen.

Carbon dioxide emission and the environment

Carbon dioxide emissions have been the greatest threat to the self sustaining ecosystem. Scientists have argued that reducing the emission of carbon dioxide in the atmosphere will divert the current degradations of the ecosystem which threatens life in the planet. Despite these claims, there have been increased emissions of carbon dioxides into the atmosphere as the use of fossil fuels increases due to the high demand for energy in the global economy. This situation has been made worse by clearing of forests to create land for settlement and agriculture due to increased world populations. The forest acts as a natural regulator of the amount of carbon dioxide in the atmosphere. This trend has raised the issue of whether the worldwide economical, industrial and social development is prepared to confront the unprecedented environmental crisis associated with high carbon dioxide emissions. In theory, the world society may seem to be determined to reduce the concentration of carbon dioxide in the atmosphere but practically these attempts are hoax.
   
Since the industrial revolution over a century ago, the world society has not been prepared for or was not even aware of the environmental implications of industrialization. For that reason, the concentrations of carbon dioxide in the atmosphere has increased significantly since the industrial revolution reaching at alarming level and is expected to rise more rapidly as the world becomes more industrialized. The concentration of carbon dioxide in the atmosphere has increased from 280 ppm before the industrial revolution to over 380 ppm. This level of carbon dioxide is the highest ever experienced in the planets history. Despite this trend, the implementation of mitigation measures to reverse the situation have not been forth coming due to the short term cost that are associated with adoption of environment friendly sources of energy. There are several negative effects of taking these measures due to the time constant and cost for deployment of necessary technologies. However, these economic impacts are nothing compared to the effect of carbon dioxide emission to the ecosystem (ASME, 2009).   
   
The environmental implications of these high amounts of carbon dioxide in the atmosphere together with other greenhouse gases are far reaching. The cost of these implications in the ecosystem and the human society can be directly attributed to lack of proper mitigations measures. The interventions to the increased carbon dioxide emission especially in the developed countries throughout the 20th century have not been swift enough leading to the resultant climate change. Research indicates that the climate change being experienced in the world today can only be averted if the carbon dioxide emissions are reduced. 

The major problem associated with the control of carbon dioxide emissions in the world is the high dependence on fossil fuel by the mechanized economy of the world. The economic issues associated with the complex fossil fuel constrained industrial world have made the intervention suggested by scientists impractical to some extent. However, these interventions are within reach both technically and economically but require integrated efforts between all the governments of the world, major players in the industrial world, the society and the scientists. Moreover, more investment in industrial research is required to demonstrate the feasibility of the proposed intervention by developing and enabling cost effective technologies. As the world economy changes, the relevant authorities should be very vigilant in the implementation of the proposed measures which will significantly reduce the emission of greenhouse gases especially carbon dioxide (ASME, 2009).

All of the matters in the universe are composed of atoms or elements. These elements are very minute particles. Elements come in group to produce the matter that humans can see. Matters that have a specific proportion of the type of elements are called compounds. Water for example is composed of 2 parts hydrogen and 1 part oxygen by number of atoms. If in case a given substance contains 3 hydrogen atom and 1 oxygen atom, then even if it composed of hydrogen and oxygen, it will never be  considered as water. Like elements, compounds are considered as pure substances. There are also combinations of substances that are not affected by the proportion of the combined substances and cannot be separated into elements by physical means. They can only be separated into elements using chemical means. These are called mixture. Example of these is a mixture of salt and water. Even if the proportion of salt to water in the mixture varies, the resulting mixture will still be a salt water mixture. Unlike compounds, mixtures are not considered as pure substance and can be separated into other substances by physical means (Kotz  Treichel, 1996).

Compounds are generally named using the names of the elements that composed them. Hence, it a pure substance can be classified as either element or compound by knowing its name. A complete list of known elements and their chemical symbols is listed in many references. It the name of the pure substance is included in the list, it is an element. However, the reverse is not always true since there are compounds that are composed of only 2 or more of the same element. A more accurate way is by knowing its chemical formula. If the chemical formula of the pure substance is composed of different chemical symbols of elements or if it is composed of more than one atom of an element, then it is a compound. The disadvantage of this is that the chemical formula is not always readily available. Other methods are necessary, like line emission spectra. This technique utilizes the fact that an element possesses unique line spectra. If the pure substance showed line spectrum of different elements, then it is a compound.

Elements do not readily group with other elements to form a compound. Some rules are satisfied first before a compound is formed and these rules depend on the nature of element, such as its charge. If the elements to be combined are both negatively charged, the compound is called covalent compounds and the bonds that exist between the elements are called covalent bond. If it is composed of elements of opposite charge, it is called ionic compounds and the bonds that exist between the elements are called ionic bond (Carpi, 1999). 
 Ionic bond is easy to understand. It is well known that opposite charges attracts while same charges repeal. Since the charges of the elements present in ionic compounds are opposite, the elements will attract each other by electrostatic force. The charge also reflects the need to give up or attain electrons. A negative charge indicates that the atom requires additional electrons while positive charge indicates the need to give up electrons. Since the charges of elements in ionic compound are opposite, one must give up and while one must accept electron. In this process, the bond between elements in ionic compounds is produced. Example of these compounds are CaBr2 (calcium bromide) and NaCl (sodium chloride).

The bonds for covalent compounds are produced in a different way. It can be expected that the elements will repeal each other due to them having the same size, but in reality bonds are still formed. Since all the elements are negatively charged, all must accept electron. However, no other source of electron is present and so the only solution is for the elements to share electrons. The shared electron becomes property of the forming elements. Examples of these compounds are NF3 (nitrogen trifluoride) and PCl3 (phosphorus trichloride) (Kotz  Treichel, 1996).

CHEMISTRY

What are the most important concepts you have learned this week   
The concepts regarding Acids and Bases are the important concepts presented today. In the field of chemistry these 2 are essential in the study and understanding the difference among substances. We can differentiate various substances by identifying them by these 2 classifications. I have also learned about the concepts regarding pH Balance and its connection with the presence of hydrogen ions.

What would you recommend to your managementleadership based on these concepts   
Based on these concepts substances can be accurately measured and identify by applying basic chemistry concepts such as these. Further studies and even experimentation can be recommended.   

How will these concepts impact you personally and professionally  
These have impact my prior knowledge and concepts of materials and substances around. Even substances need to be balance and to recognize their extremes. Everything has its uses or advantages. There is also a need to balance things out and anything that is too much or too little can cause some harm. For example, too much acid in the stomach is not good after all.
What is the value added from these concepts, or what differences can these concepts make to your organization
   
These concepts can provide patterns or suggestions on how we can balance things. The concepts can be applied to determine chemical reactions among substances.
Describe important references used this week.
   
The references used this week include articles that provide introductory explanations as well as sample lab exercises regarding Acids and Bases. These references provided overview of the topic as well as clear examples, definitions and chemistry concepts.

CHEMISTRY

How do over-the counter calcium carbonate or magnesium carbonate antacid medications work
   
Calcium carbonate (CaCO3 ) and magnesium carbonate (MgCO3) are 2 of the most common compounds found in many commercial OTC antacids. Antacids are basically known as base or alkaline and therefore are capable to neutralize acids. They worked by effectively neutralizing the acid mainly known as Hydrochloric acid (HCl) secreted in the stomach. When in excess, HCl can bring what we call hyperacidity or heartburn. HCl is actually an important compound found in gastric juices and is being secreted in the stomach for the enzyme pepsin to catalyze the digestion of proteins.
 Antacids moreover are also known as weak bases as they have pH level of 10 and considering the highest is pH level of 14. Antacids do helped reduce the level of acids in the stomach, but since HCl is an important part of the gastric juice the antacids need not be too strong to neutralize the acids.
    In the process of neutralization acids are known to release H  or hydrogen ions while bases release OH-. This would result in producing either water (H2O) and even salts. Chemical reaction will then take place in the stomach and the HCl will be reduced through neutralization.  After which, it can release either water, salt or even carbon dioxide gas such as in this sample chemical formula or equation of  CaCO3   2HCl  CaCl2 H2O  CO2.