The path of blood Essay Example for Free

The path of blood Essay The path blood take from the right femoral vein to lower lobe of the right lung via the pulmonary artery is as follows; we start in the right femoral vein which is located in the thigh and travel to the right external iliac vein. Blood from the femoral vein emptiness in the inferior vena cava but first must travel through the external iliac. The iliac vein joins with the inferior vena cava. The inferior vena cava takes deoxygenated blood form the lower limbs of the body to the right atrium (Thibodeau, Patton, 2008. ). Following the inferior vena cava we travel in to the right atrium of the heart. The purpose of right atrium of the heart is to receive deoxygenated blood from the body through the inferior vena cava and pump it into the right ventricle (MedicineNet.com, 2012). Once we are ready to leave the right atrium we go into the right AV valve (AV is atrioventricular or cuspid, (Thibodeau, Patton, 2008.).The AV valve stops blood from flowing backwards and every time the heart beats the valve opens and closes. The AV valve allows blood to flow into the right ventricle. But before blood goes into the right ventricle it has to travel through the tricuspid valve. The tricuspid valve along with AV and SL are all structures that prevent blood from flowing backwards (Thibodeau, Patton, 2008.). So we now know that the right ventricle receives deoxygenated blood from the right atrium, but what we don’t already know is that the right ventricle sends the [continues]

Traditional Monoclonal Antibodies and Recombinant Antibodies

Traditional Monoclonal Antibodies and Recombinant Antibodies Introduction: Antibody is a special molecule that present in our bodies to fight against infections and stimulate immune response. Typical antibody is a Y shaped molecule consists of two H (heavy) and two (light) chains. Two antigen-binding fragments (Fabs) are linked with a constant region (Fc)(Brekke and Sandlie 2003). After the discovery of murine monoclonal antibodies produced by hybridoma cells developed by Kohlor and Milstein(Kohler and Milstein 1975), the role of monoclonal antibodies in therapeutics and clinical diagnostics are increasingly important in the last three decades (Laffly and Sodoyer 2005). The term monoclonal antibody is defined as an antibody molecule which is monospecific and derived from a single B cell clone. Results in using fully murine monoclonal antibodies in therapeutics are not ideal and problems aroused in triggering unwanted human immune responses. These problems force the generation of recombinant antibodies in the replacement of traditional monoclonal antibodies. Tailor-made recombinant antibodies fragments increase flexibility both in immunotherapy and immunodiagnostics. The application of minimal form of functional antibodies single-chain antibodies (scFvs) are the most popular form of recombinant antibodies fragments as diagnostic agents (Hagemeyer et al. 2009). In this assignment, the comparison between traditional monoclonal antibodies and recombinant antibodies as therapeutics agents and diagnostics tools will be discussed. From the example of tragedy TGN 1412, the potential risk of using recombinant antibodies in therapeutic agents should not be ignored. Finally, future perspective of recombinant antibodies in gene therapy and using polyclonal antibodies as novel immunotherapeutic strategy will be discussed. Theoretically, probably any kind of monoclonal antibodies can be produced with the aid of hybridoma technique. The continuous culture of hybridoma cells creates an inexhaustible supply of monoclonal antibodies in the laboratories by cell culture or rodent(Nelson, Reynolds et al. 2000). Its highly specificity, stability and homogeneity are ideal for diagnostics and in therapeutic purposes. After the introduction of the first FDA approved drugs OKT3 launched into the market in 1986, the results of using fully murine monoclonal antibodies in human was not promising (Chatenoud, Baudrihaye et al. 1986; Chatenoud, Jonker et al. 1986). This is because murine originated monoclonal antibodies triggered several immunogenic responses in human body. One of the problems arise is human anti-mouse antibodies (HAMA) or anti-globulin antibodies (HAGA) response (DeNardo, Bradt et al. 2003; Presta 2006) generated against the administrated murine antibodies. Studies showed that around 30-75% of patients with solid tumors and relapsed B-cell malignancies developed HAMA response after exposure to murine antibodies (Smith, Nelson et al. 2004; Majidi, Barar et al. 2009). The activation of HAMA response is mainly due to the host antibodies generated against the idiotopes of the administered murine antibodies. Moreover, rapid clearance of murine Abs shortens its serum half-life and relatively ineffective to trigger cytotoxic effect (e.g. ADCC and CDC) compared to human antibodies hindered murine Abs as therapeutics agents (Presta 2006). Based on the above unresolved problems, with the aid of genetic engineering, murine monoclonal antibodies are modified to become less immunogenic and enhance potency in therapeutics and diagnostics. Three different types of recombinant antibodies are generated: chimeric, humanized and human antibody. In chimerization, the murine variable region is fused with the human constant region forming chimeric antibodies(Presta 2006). This modification imitates the human immune system. Although chimeric antibodies is less immunogenic but may trigger human anti-chimeric antibody responses (HACA)(Baert, Noman et al. 2003). Further maturation technique is humanization (hyperchimeric). In this technique, only the complementarity determining regions (CDRs) from the murine antibody was grafted into a human constant and variable regions (Smith, Nelson et al. 2004). By resurfacing, reshaping and hyperchimerisation of hyperchimeric antibody, the antibody binding affinity improved. Although the above me thods minimize immunogenicity, but immune response result of xenografting may occur. Finally, human antibodies can be generated by transgenic mice and in vitro combinatorial libraries (Brekke and Loset 2003; Brekke and Sandlie 2003; Presta 2006). Antibodies which generated under this method are expected to be identical to human antibodies with clinical significant without any side effects. One of the examples in combinatorial library approach for the selection of antibodies is by phage display technology in which antibody variables domain are expressed as fusion protein as coated on the surface of the bacteriophages. Under combinatorial library approaches and transgenic mice, the chance of getting fully human antibodies are higher when compared to hybridoma and chimeric antibody technologies. In addition, single-chain variable fragment (scFv) and Fab fragment can be isolated (Brekke and Loset 2003; Brekke and Sandlie 2003). Therapeutics application Fc portion in an intact antibody trigger effector function which is undesirable for therapeutic applications. Therefore, for a desirable antibodies design for cytokine inactivation or receptor blockage, the main considerations of antibody design are: size, tissue penetration, distribution, half-life, effector function, affinity, stability and immunogenicity. scFv and Fab fragments are preferred as choice of preference when compared to traditional antibodies because of smallest in size, high binding affinity, specificity, good tissue penetration and reducing immunogenicity due to HAMA response. scFv and Fab antibodies have a shorter half-life than whole antibodies and this drawback can be overcome by PEGylation. In addition, the attachment of PEGylation of murine monoclonal antibody reduces HAMA response of the host after administration(Laffly and Sodoyer 2005). Applications of monoclonal antibodies are vastly employed in therapeutic agents (e.g. treatment of cancer) and in clinical diagnostic (e.g. histopathological diagnosis). Humanized mAbs (transgenic mice) (resurfacing, reshaping and hyperchimerisation, etc) Phage display technology (Fabs and Fvs) In recent years MAbs have become very important commercial reagents, and currently contribute to over 30% of biopharmaceuticals in development and production. To date, 10 different MAbs have achieved FDA approval, with others in phase III trials.4 Applications Antibody conjugates (Majidi, Barar et al. 2009) Unconjugated mAbs (Majidi, Barar et al. 2009) rAbs for cancer therapy immunohistology genetic immunotherapy(Pelegrin, Gros et al. 2004) scFv for diagnostics tools (size, immunosensor, inhibition of imnflammation and complement system) (Hagemeyer, von Zur Muhlen et al. 2009) Problems polyclonal vs monoclonal therapeutics (Haurum 2006) TGN1412 incident (Self and Thompson 2006) References: Baert, F., M. Noman, et al. (2003). Influence of immunogenicity on the long-term efficacy of infliximab in Crohns disease. N Engl J Med 348(7): 601-608. Brekke, O. H. and G. A. Loset (2003). New technologies in therapeutic antibody development. Curr Opin Pharmacol 3(5): 544-550. Brekke, O. H. and I. Sandlie (2003). Therapeutic antibodies for human diseases at the dawn of the twenty-first century. Nat Rev Drug Discov 2(1): 52-62. Chatenoud, L., M. F. Baudrihaye, et al. (1986). Restriction of the human in vivo immune response against the mouse monoclonal antibody OKT3. J Immunol 137(3): 830-838. Chatenoud, L., M. Jonker, et al. (1986). The human immune response to the OKT3 monoclonal antibody is oligoclonal. Science 232(4756): 1406-1408. DeNardo, G. L., B. M. Bradt, et al. (2003). Human antiglobulin response to foreign antibodies: therapeutic benefit? Cancer Immunol Immunother 52(5): 309-316. Hagemeyer, C. E., C. von Zur Muhlen, et al. (2009). Single-chain antibodies as diagnostic tools and therapeutic agents. Thromb Haemost 101(6): 1012-1019. Haurum, J. S. (2006). Recombinant polyclonal antibodies: the next generation of antibody therapeutics? Drug Discov Today 11(13-14): 655-660. Kohler, G. and C. Milstein (1975). Continuous cultures of fused cells secreting antibody of predefined specificity. Nature 256(5517): 495-497. Laffly, E. and R. Sodoyer (2005). Monoclonal and recombinant antibodies, 30 years after. Hum Antibodies 14(1-2): 33-55. Majidi, J., J. Barar, et al. (2009). Target therapy of cancer: implementation of monoclonal antibodies and nanobodies. Hum Antibodies 18(3): 81-100. Nelson, P. N., G. M. Reynolds, et al. (2000). Monoclonal antibodies. Mol Pathol 53(3): 111-117. Pelegrin, M., L. Gros, et al. (2004). Monoclonal antibody-based genetic immunotherapy. Curr Gene Ther 4(3): 347-356. Presta, L. G. (2006). Engineering of therapeutic antibodies to minimize immunogenicity and optimize function. Adv Drug Deliv Rev 58(5-6): 640-656. Self, C. H. and S. Thompson (2006). How specific are therapeutic monoclonal antibodies? Lancet 367(9516): 1038-1039. Smith, K. A., P. N. Nelson, et al. (2004). Demystifiedrecombinant antibodies. J Clin Pathol 57(9): 912-917.

Contrastive Analysis And Error Analysis

Contrastive Analysis And Error Analysis Contrastive analysis is a method to distinguish between what are needed and not needed to learn by the second language learner by evaluating languages (M.Gass Selinker, 2008). In addition, contrastive analysis is a technique to identify whether two languages have something in common which assess both similarities and differences in languages, conforming to the belief in language universals. (Johnson, 1999). Both statements indicate that contrastive analysis holds a principle which is important in order to identify what are required by the second learner and what are not. If there is no familiar characteristic in the languages, then it is not necessary to compare the languages. While much could be said about comparing languages, a more important aspect is about influence from L2 in L1. Contrastive analysis stresses the influence of the mother tongue in learning a second language in phonological, morphological, lexical and syntactic levels. It holds that second language would be affec ted by first language (Jie, 2008, p. 36). On the same score, Wardhaugh asserts that first language of second language learners can clarify all errors that are constantly made them. These arguments prove that the common mistakes make by the second language learner are explainable in the first language if there is a relation in both languages. Indeed, this idea is conform to the rule of contrastive analysis which believes in language universal. On the other hand, contrastive analysis is used to identify one language origin and connection between the languages with other languages if it does. In Robert Lados words (1957:p.2): The fundamental assumption is transfer; individuals tend to transfer the forms and meanings, and the distribution of forms and meanings of their native language and culture to the foreign language and culture. I agree with Robert Lado since the second language learner tends to use direct translation to make a complete sentence. However, this might become a problem when the placement of the part of speech is not the same. For example, Malaysian who use Malay language as their first language and English as their second language might have a problem in placing the adjective. This is because in Malay language, adjective is put after the noun, such as; Rumah yang cantik but in English, adjective is placed before noun, for instance A beautiful house (adj) (Noun) This may cause confusion for the second learner but if they make a sentence, it is still understandable. The degree of clarity of the sentence can be a positive transfer of negative transfer. This example is supported by Jie (2008): In the course of language learning, L1 learning habits will be transferred into L2 learning habits. Therefore, in the case of L1 transfer into L2, if structures in the MT have their corresponding structures in the TL and L1 habits can be successfully used in the L2, learners would transfer similar properties successfully and that would result in positive transfer. Contrastingly, in the case of negative transfer or interference, certain elements of the MT have no corresponding counterparts in the TL, L1 habits would cause errors in the L2, and learners would transfer inappropriate properties of L1 It is important to know that L2 learners be likely to apply their L1 grammatical system in L2 grammar (Smith, 1994). They would opt for L2 words those they familiar, blending them using L2 grammar to formulate a sentence. For example; a Malay speaker would say; Saya makan epal semalam (Pronoun) (Verb) (Noun) (Adverb) Or in English; Yesterday, I ate the apple (Adverb) (Pronoun) (Verb) (Determiner) (Noun) If the L2 learners apply Smith argument, they would say; I ate apple yesterday As mentioned earlier, this statement is logical at one point but in other point, it shows that errors and transferred inappropriate properties those made by L2 learners are noticeable and this should apply the rule of contrastive analysis. However, this analysis has disadvantages. In Susan M. Gass and Larry Selinker words, they believe that this analysis is questioned because of the concept of difficulty as the basic theory of the contrastive analysis is concerning the difficultness. If an error is made by a person, this shows that the person has problem in some area, not because of the native language. Thus, we cannot presume that fluency of a L2 learner in L2 is depending on the nature of L1. There are more aspects that related to this matter. There are other factors that may influence the process of acquisition such as innate principle of language, attitude, motivation, aptitude, age, other language knownà ¢Ã¢â€š ¬Ã‚ ¦ (M.Gass Selinker, 2008). Next, contrastive analysis cannot d etect some difficulties experienced by the L2 learners. For example, Je vois les/elle/la/le . I see them/her/her/him(this phrase is not possible in French) (Choi, 2009). Error analysis is a type of linguistic analysis that focuses on the errors learners make (M.Gass Selinker, 2008). This analysis is almost the same with the weak version of contrastive analysis which is comparing the errors which made by L2 learners. However, error analysis is not evaluating the errors with L2 native language, but it compares with the target language. Error analysis provides a broader range of possible explanations than contrastive analysis for researchers/teachers to use account for errors, as the latter only attributed errors to the native language (M.Gass Selinker, 2008). I do agree with Gass and Selinker because as Corder (1967) says that by producing errors, it shows that the learners are progressing and participating.

A Place to Go - Original Writing :: Papers

A Place to Go - Original Writing Night after night I had passed the strange location. I began to recognize it and became aware of every detail. I found the building light in the same way. My eyes became attracted, addicted to this place, every eve it beckoned me to return. Simply gazing on it seemed to provide a relaxation, it warmed me. My body became accustomed to its feeling and presence; I found it, almost difficult to leave it. Despite this I had to carry on, they where close behind me now. This was not the first time that I had passed the building and approached it with curiosity. I had wandered here before. This building seemed of some overwhelming significance, when near I felt pathetic and feeble, this building, mansion or 'castle' seemed to posses some great inhuman power far beyond my conceivable imagination. As previously I waited and rested near to the building, my back lay vertical against the huge wall, again this unbelievable feeling of nostalgia, anomalous refreshment and suspicion passed through the very material of my being. It happened suddenly. I was unrepentant, almost unaware of this 'attack' I was about to undergo. I felt a hard thud to my right, this failed to affect me, and I was dazed and confused by the sheer marvel of this magic place. The second warning was more obvious and harder to ignore. A hand was placed on my shoulder. The way in which it touched me was indescribable, there was no feeling or emotion in this being I was now contemplating. I pondered its nature for a while, until the hand did seem to posses a feeling, an emotion; the hand now gripped my shoulder with intensity, a feeling of urgency and aggression showered over me. I was now left with now choice but to confront this creature. I slowly turned my head. I could see, in the corner of my eye a man. A tall man. A big man. An old man and an interesting man. This aggression and urgency flourished and eventually disappeared,

Comparison essay amd vs intel -- Computer Science

Comparison essay amd vs intel English III Throughout personal computer history there has been a monopoly on processors that company is Intel but that is changing by the day. There is a processor called AMD (advanced micro devices) currently leading in the silicon race for the fastest processor at an affordable price. No longer shall Intel lead the market when AMD makes its name superior. A CPU is a microprocessor that is generally constructed with millions of tiny switches called transistors that are imbedded in silicon. The outer shell is ceramic with gold pins protruding out of the processor to make a connection with the motherboard. The function of the processor is to take the data from memory, (a storage device) or an outside controller like a keyboard, joystick, or scanner. This is determined in the program by sending messages to the processor in binary language. Binary language is sent to the processor commanding the transistors to flip on or off, (on equals one and off equals zero). The processor is placed on a motherboard with a bus speed of that to match the processor. This allows the processor to go as fast as the wires making up the bus can handle. This means the less resistance in the wire the faster your system can run. The bus is measured in megahertz (MHz) and is connected to the memory for the processor to store in memory. The faster the operation can occur the better the system operates. The CPU has a clock speed that tells you how many operations can happen in one second. A CPU's clock is found by multiplying the processor megahertz by 1,000,000. If you have a 500 MHz processor then the operations will equal 500,000,000 per second. The operation, is the individual commands sent by the program. The faster the processors bus and clock speed the faster FPU's (floating point units). This is the mathematical part of the processor. This allows the binary to work faster. Now that the processor has been explained. Why is AMD is better? In the beginning, AMD made CPU's (central processing units) in the second IBM compatible desktop systems ever developed. There are now three competitors in the processor race; AMD, Intel, and Transmeta Crusoe. The relevance of this is that Intel's Processor will still be the most expensive CPU with no extras. Intel has had problems in the past as Kam, from the UK says, "It... ...an AMD Athlon. Networking is a complicated job with older slower computers; the Athlon is the key to the networking stability. This makes a network with minimal problems and high-end data pass through possible. There is a bottleneck theory that is related to memory and networking. In memory it is caused by having to slow of memory on to fast of a bus. This will not happen if the AMD Athlon System has PC133 memory. Intel had programs made by the monopolization of Microsoft Windows 3.1x, 95x, 98x this made it hard for AMD to compete in the past. Microsoft Windows 2000 will now incorporate programming made to run windows faster more reliable and be compiled to run better on the Athlon systems. With Intel out of the way, on top end networking AMD can pull into the lead in one more area. Listen to what AMD has to say about this project. "Microsoft and AMD worked together throughout the design process to help ensure the combination of floating-point performance of the AMD Athlon processor and Microsoft's Windows 2000 Professional will provide a reliable and high-performance business platform that meets the needs of business customers today and well into the future." Comparison essay amd vs intel -- Computer Science Comparison essay amd vs intel English III Throughout personal computer history there has been a monopoly on processors that company is Intel but that is changing by the day. There is a processor called AMD (advanced micro devices) currently leading in the silicon race for the fastest processor at an affordable price. No longer shall Intel lead the market when AMD makes its name superior. A CPU is a microprocessor that is generally constructed with millions of tiny switches called transistors that are imbedded in silicon. The outer shell is ceramic with gold pins protruding out of the processor to make a connection with the motherboard. The function of the processor is to take the data from memory, (a storage device) or an outside controller like a keyboard, joystick, or scanner. This is determined in the program by sending messages to the processor in binary language. Binary language is sent to the processor commanding the transistors to flip on or off, (on equals one and off equals zero). The processor is placed on a motherboard with a bus speed of that to match the processor. This allows the processor to go as fast as the wires making up the bus can handle. This means the less resistance in the wire the faster your system can run. The bus is measured in megahertz (MHz) and is connected to the memory for the processor to store in memory. The faster the operation can occur the better the system operates. The CPU has a clock speed that tells you how many operations can happen in one second. A CPU's clock is found by multiplying the processor megahertz by 1,000,000. If you have a 500 MHz processor then the operations will equal 500,000,000 per second. The operation, is the individual commands sent by the program. The faster the processors bus and clock speed the faster FPU's (floating point units). This is the mathematical part of the processor. This allows the binary to work faster. Now that the processor has been explained. Why is AMD is better? In the beginning, AMD made CPU's (central processing units) in the second IBM compatible desktop systems ever developed. There are now three competitors in the processor race; AMD, Intel, and Transmeta Crusoe. The relevance of this is that Intel's Processor will still be the most expensive CPU with no extras. Intel has had problems in the past as Kam, from the UK says, "It... ...an AMD Athlon. Networking is a complicated job with older slower computers; the Athlon is the key to the networking stability. This makes a network with minimal problems and high-end data pass through possible. There is a bottleneck theory that is related to memory and networking. In memory it is caused by having to slow of memory on to fast of a bus. This will not happen if the AMD Athlon System has PC133 memory. Intel had programs made by the monopolization of Microsoft Windows 3.1x, 95x, 98x this made it hard for AMD to compete in the past. Microsoft Windows 2000 will now incorporate programming made to run windows faster more reliable and be compiled to run better on the Athlon systems. With Intel out of the way, on top end networking AMD can pull into the lead in one more area. Listen to what AMD has to say about this project. "Microsoft and AMD worked together throughout the design process to help ensure the combination of floating-point performance of the AMD Athlon processor and Microsoft's Windows 2000 Professional will provide a reliable and high-performance business platform that meets the needs of business customers today and well into the future."

Man vs. Computer Essay

Since the beginning of time, man has thought up and brought to fruition countless inventions. Each has been more ingenious than the last. The human mind has created such brilliant things, but the computer may have been its greatest creation. It is ever changing, evolving and growing â€Å"smarter†. However, as the computer has evolved, mankind’s value may be threatened. The computer has already begun to overtake many of the vital functions that man has prided himself upon. While neither the mind nor the computer are perfectly productive on their own, they complement each other, and together create a more efficient way of living. Our lives are now dependent upon the computer and what it tells you. Even now as I type this journal entry on my computer, I am fully convinced that it will produce a result for me that is far superior to what I can manage using only my own two hands. It has been commonly said that the computer can never replace the human brain, because it was humans that created them. Is this a good reason why the computer must be inferior to humans? A computer has the ability to evaluate problems that humans can hardly even imagine, let alone approach. Even if a man can calculate the same problems as a computer, the computer can solve it much faster than the human mind. Maybe it is the subconscious attempt by us at reaching the next stage of evolution by our minds, creating a machine to do all the dirty work for us while we sit back and allows our brains to focus on creating, or destroying, as the case may be. The human brain has many flaws, yet it also has many an edge over the computer. It has the capacity to create, unlike the computer. It can work without full input, making logical assumptions about problems. A person can work with a wide variety of methods, seeing new and more efficient ways of handling problems. It can come up with infinite ways of getting around problems encountered in everyday life, while a computer has a limited selection of new tricks it can come up with, limited by its programming. Given the time, the human brain can learn to understand anything, and it can grasp the central theme of any concept. The computer tends to take all things in their entirety, which makes some problems near impossible to solve. Emotions are also an asset. Emotions have allowed the human brain to evolve beyond a problem-solving machine. Anger allows the imagination to roam, inventing concepts of new and more powerful weapons of destruction. Discontent induces the mind to conceive of new methods of fulfillment that could be expanded into something more. Puzzlement causes the mind to think of solutions. Curiosity leads to attempts to satisfy it, producing new discoveries and revelations. The human brain is as incredible as it is flawed, and the computer is a fantastic machine, but seriously lacking in many aspects. Perhaps the computer is not truly a competitor with the human brain, but rather it’s ideal. Don’t those who use the computer do so in order to supplement their own creative input? After all, the computer is far superior to the human brain in those aspects where the brain is weakest. Neither the mind nor the computer would be as good as the two of them are when they are working together.

Ozone Depletion Essay

The Ozone layer is located in the Earth’s upper atmosphere. It acts as a barrier and absorbs majority of UV radiation before it hits Earth’s surface. Ozone is made up of three oxygen atoms that are naturally occurring molecules. The depletion of the ozone has become a worldwide issue and is caused by the release of CFCs into the atmosphere. CFCs release chlorine atoms which break down ozone molecules. The depletion of the ozone layer threatens to leave life on Earth unprotected from UV radiation. Chlorofluorocarbons (CFCs) contain chlorine, fluorine and carbon atoms. CFCs can be found in spray cans, in the plastics industry and in refrigerants. When UV rays in the upper atmosphere hit CFC molecules, a carbon-chlorine bond breaks leaving a single chlorine atom. This chlorine atom reacts with the ozone molecule causing it to breakdown. The breakdown of ozone leaves an ordinary oxygen molecule (O2) as well as a chlorine monoxide molecule. Because UV radiation breaks oxygen molecules into single oxygen atoms, the single oxygen atom then breaks up the chlorine monoxide. With the chlorine atom left by itself, it is then able to repeat the process of breaking down more ozone molecules. However, the depletion of the ozone is not only caused by CFCs. Halons, CH3CCI, CCI4, HCFCs, hydrobromofluorocarbons and methyl bromide are all linked with ozone depletion leaving life on earth vulnerable to the effects from exposure to UV radiation. With the depletion of the ozone, UV radiation becomes more accessible to life on Earth and effects from this radiation follow. Since ozone filters UV radiation, with ozone depletion comes higher levels of UV radiation hitting the surface of the Earth. The increase in ultra-violet rays consequently mean higher risk of skin cancers and cataracts in humans and animals. Higher levels of this radiation also damages materials such as plastics, harm certain crops as well as marine animals. Extra UV radiation deters the natural reproductive cycle of phytoplankton (a single celled organism at the bottom of the food chain) Scientists fear that the population of other species will decrease with the loss of phytoplankton. Since the depletion of the ozone layer, researchers have recognised obvious deviations in the reproductive rates of fish, shrimp and crabs as well as frogs and salamanders. These changes in organism’s reproductive rates and higher risks of skin cancer and cataracts can all be linked to the depletion of the ozone layer. Since CFCs have been released into the atmosphere, Earth’s naturally occurring ozone layer has been depleting. The ozone layer above the Antarctic has been majorly affected by CFC pollution since the mid 1980’s. However, CFCs were banned in 1987 to prevent further damage to the ozone layer. Results of ozone depletion can be dramatically seen throughout the southern spring and summer when the sun shines for longer periods at a time. Due to chlorine reacting with the Ultra-violet rays, ozone is destroyed on a scale of up to 65% during these months. Even though CFCs were banned in the 1980’s scientists estimate it will take another 50 years for chlorine levels to return to their natural levels. With CFCs being emitted into the atmosphere, the breakdown of ozone has resulted. Without the ozone filtering UV rays, higher levels of radiation are able to hit the Earth’s surface leading to higher rates in skin cancer and cataracts. Ozone depletion has also been linked with the obstruction of organisms natural reproductive cycles. Although they were banned in the late 1980’s, CFCs will continue to be present in the atmosphere for many more years causing ozone depletion to remain a worldwide issue.