19.Stephany+Raventos

//2/4/2012//

> In medicine , radioisotopes and radiation sources are used for diagnostic purposes , for anatomical and functional information on the health status of patients, or in therapy for the treatment of malignant tumors. Usually , applications of ionizing radiation sources are classified into three areas: nuclear medicine , radiotherapy and radiology. > > -60Co (cobalt -60) for the treatment of cancer. > > -Certain cancers can be treated internally with radioactive isotopes , such as thyroid cancer, iodine goes to the thyroid and treated with sodium iodide ( <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif;">NaI) containing <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif;">iodide ions from radioactive iodine <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif;">-131 <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif;">or iodine <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif;">-123. > > -<span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">Arsenic <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">-73 <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">is used as a tracer for estimating the amount of arsenic absorbed by the body and arsenic <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">-74 in locating <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">brain tumors. > > <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">Cobalt may also exist in radioactive forms <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">. <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">A radioactive isotope of an element constantly emits radiation <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">, which can <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">transform into an isotope of a different element or a different isotope of the same element. The nuclide that is formed may be stable or radioactive. This process is called radioactive decay. The 60Co is the most important isotope of cobalt and produced by bombarding natural cobalt <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">, <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">59Co with neutrons in a nuclear reactor <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">. <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">The 60Co decays by emitting a beta ray or electron, and becomes a stable nuclide of nickel (atomic number 28). The decay is accompanied by the emission of high energy radiation called gamma rays. The60Co is used as a source of gamma rays used to sterilize medical equipment and consumer products in chemotherapy for cancer patients and to manufacture plastics. > //4. List the pros and cons of using radioisotopes in medicine.// __<span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">Pros: __ <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">-Supplying it in adequate doses <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">, radioactivity <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">can cure serious diseases such as some cancers and detect other types of disease, which formerly were difficult to diagnose. -<span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif;">Normally serve to diagnose and locate tumors. -<span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">They are used for the treatment of cancer. <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;"> -The radiation is used to kill malignant cells. -<span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif;">can be used to identify blocked blood vessels.
 * 1. What are radioisotopes used for in medicine?
 * //2. Provide 3 examples of a radioisotope and list where it is used.//
 * //3. Choose one of your examples and describe the process.//

__<span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">Cons: __ <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">- It can <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">be dangerous if not taken appropriate action.The radioisotopes may be highly radioactive and an exhibition of just milliseconds could be lethal. <span class="hps atn" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">- <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">Sometimes <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">the application is unclear. For example <span style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">, <span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">radiation therapy to the cure of some tumors is ofteneffective, but not always appropriate and its applicationcan be quite controversial. -<span class="hps" style="background-color: #f5f5f5; color: #333333; font-family: arial,sans-serif; font-size: 16px;">Some radioactive elements take decades or even centuries to disintegrate depending on the dose used.

//__**Learning prep : 02/05/12**__// <span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">1) __<span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">Advantages __ <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">:

<span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;"> -In the terrestrial environment, an advantage <span class="hps" style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">would be the low viscosity features <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">, <span class="hps" style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">because it allows greater ease of movement for living organisms. <span class="hps" style="font-family: 'Arial Black',sans-serif; font-size: 10pt;"> -In Aquatic Environment, the high buoyancy is an advantage, because water provides greater support for an organism (this support is more than a mere upward thrust), compared to the terrestrial environment that organisms have to support their own bodies (bones, skeleton). - <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">Lower level of heat conduction permits the retention of heat within the body of an animal for a longer period of time in the terrestrial environment.

__<span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">Disadvantages: __ <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;"> -High viscosity in aquatic environment, because it makes it difficult for organisms to move through. So an animal’s shape will need to be streamline to help with the movement. <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;"> -Low Buoyancy in terrestrial environments, since plants and animals need to be able to support themselves. <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;"> -The higher level of heat conduction in aquatic environments, due to their lose of heat from their body , this is because water conducts heat better than air and can finally cause a kind of hypothermia.

<span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">2) <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">Many aquatic animals have a streamlined shape, which allows them to move more easily in water <span style="background-color: white; font-family: 'Arial Black',sans-serif; font-size: 10pt;">through the high viscosity aquatic environment.

<span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">3) <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">Terrestrial or land animals need larger muscles and bones for support than aquatic animals, due to its low buoyancy , this means that the land animal doesn’t have the ability to support their bodies that easily than aquatic animals, because of this, they are require d <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;"> to be made up of bones and a skeleton.

<span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">4) <span style="font-family: 'Arial Black',sans-serif; font-size: 9pt;">As almost 20% of air is oxygen, it is abundant on land except at very high altitudes in contrast the concentration of oxygen or other gases in the aquatic environment are <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">dissolved in water, <span style="color: #333333; font-family: 'Arial Black',sans-serif; font-size: 10pt;">which means that they are less available as one goes down in the ocean (depth).

<span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">6) <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">a) Marine animals need to adapt to avoid excessive water loss to their aquatic environment of the availability of water and salts within the water. The marine life adapts to either fresh or salt water environments. Terrestrial organisms adapt to avoid excessive water loss depending on the terrestrial environment in which in lives within, as the availability of water varies coming a major problem for organisms in dry environments.

<span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;"> b) Freshwater organisms don’t require similar adaptations as saltwater organisms require the ability to filter the salt water and function within a different environment. Freshwater organisms do not need to have this adaptation, as there is minimum salt levels within freshwater.

<span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">7) <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">Its eternally dark on the ocean floor because light changes with depth. Light doesn’t penetrate more than 300 meters deep, so that’s why animals need to adapt accordingly to their aquatic environment.

<span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">8) <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">Air temperature generally fluctuates more than water temperature. The thermal stability of the aquatic environment derives partly from the high capacity of water to absorb heat energy without changing temperature (a capacity that chemists call specific heat). So we can say that aquatic organisms not require mechanisms to regulate their body temperature because, the temperatures are stable and are more conducive to life. <span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">9) <span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;"> a) <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">The terrestrial environment is described as having two areas considered terrestrial, such as <span class="hps" style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">land and air, with this we can infer that there are animals that stay constantly in land and others that fly like for example birds, ect . <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">While in the aquatic habitat , it consist of a single phase were just aquatic animals have the capacity and requirements to live in the aquatic environment.

<span style="color: #f79646; font-family: 'Arial Black',sans-serif; font-size: 10pt;">b) <span style="font-family: 'Arial Black',sans-serif; font-size: 10pt;">I agree with all statements, because it shows a clear comparison of the different types of environments that exist .The earth is composed of water ( aquatic environment) land and air ( terrestrial environments ). 03/05/12

__ ** Salmon, anadromous best known. ** __

Anadromous, live mostly in salt water and breed in fresh. (Greek : ana means up ).

The best-known anadromous fish are salmon, which hatch in small fresh water streams , down to the sea and live several years, then return to the same rivers where they hatched , spawn , and die soon after.

In fish, osmotic regulation ( osmoregulation) is performed by the kidney , gills and skin ( barrier). As for the balance of water and ions fish have a particular problem because the gills and oral mucosa are permeable to both water and salts.

When an eel or salmon reached freshwater in their migration route, you encounter the problem of deficiency of salts on hydration and compared with the opposite trend of the environment where it came from ( salty). A young salmon has the inverse problem in its journey to the sea.

As anadromous fish should be very versatile in osmotic adjustment, they have kidney , gills and buccal mucosa capable of supporting both income and the secretion of some ions from the diffusion gradients.

Experiments suggest that eel salt cells to secrete can function bothas to absorb salts of chlorine. Physiological adjustments to changes in salinity are genetically determined. Changes in endocrine activity are usually concurrent or precede changes in the mechanisms of balance, the pituitary gland , thyroid and gonads are in charge of the physiological changes in this respect, before or during migration.

An increase in thyroid activity has been reported in the salmon downstream migration, possibly to facilitate energy- costly processes of excretion of salt in seawater , among other functions.

(//Gambusia holbrooki)//, commonly known as the mosquito fish.
 * 08/05/12- 09/05/12**
 * __What is its scientific name?__

>
 * __Provide a diagram of the mosquito fish.__

> Mosquitofish are originally from the USA. They were first introduced in the 1920s as an aquarium fish, and later released into the rivers and creeks to help with the control of mosquitos population, however there has been no evidence that gambusia has had any effect in controlling mosquito populations or mosquito-borne diseases in Australia in 1925. > Now they are very widespread throughout New South Wales, South Australia, Victoria and in inland and coastal areas, but they are not found in Tasmania. <span style="-webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; border-collapse: separate; color: #333300; font-family: Arial,Helvetica,sans-serif; font-size: 12px; line-height: 18px;">TODAY : The numbers and __ [|distribution] __ of Mosquitofish have increased dramatically since they were first introduced into Australia. Mosquitofish are found in mountain streams through to rivers on the plains, and in lakes and dams, wetlands and __ [|estuaries] __. They can tolerate wide ranges in temperature and __ [|salinity]. __ || > The mosquito fish also has adaptations to their outer body that helps them survive in their environment. The end of their snout is symmetrical so they are suited to prey in open water. Their eyes are small, allowing them to live in shallow water like puddles. Compared to their body, they have a large, forked, caudal fin, which along with its torpedo (stream line) shaped body and its small scales, makes it a strong, fast swimmer. Both sides are flat, so the fish is almost invisible from its front and rear sides, allowing it to feed without being seen. The fish is hump-backed, meaning it can also live in fast moving water like streams. The mosquito fish also has many adaptations to its colour, which help it survive. It has no markings, except for a false eye spot on its tail. This is so, if attacked, the predator will attack the tail, giving the mosquito fish a chance of escaping. The fish also has counter-shadowing, meaning it is dark coloured on the top and light coloured on the bottom. This is because the sea is darker at the bottom, so the fish will blend in, avoiding predators from the top. The sea is brighter at the top, so the mosquito fish will also avoid predators from the bottom. > > They can live in warm, still, slow flowing water and many other water types, so they can easily live in any water environments. This will increase the species chance of survival. They can withstand water temperatures from <5 ̊C to 44 ̊C, so if there is any sudden temperature change in the water, they can still survive, while other species die off. Their diet includes a range of organisms like terrestrial, aquatic insects and mosquito larvae. This means they can survive on many organisms, so a fall in the organism's population will not affect them. Because they can live in any environments, they need to get adequate oxygen from the atmosphere. They do this by coming up to the surface and gulping in air. > The numerous adaptations of the mosquito fish greatly affects it's abundance and distribution. Because of their high ability to survive, their abundance is very high. Their high abundance affects their ecosystem, being a limiting factor of other species. Many native species are ceasing to survive because of the introduced mosquito fish, which unbalances the ecosystem's food web. The mosquito fish's many adaptations also increase the species' distribution. Because of its ability to live in many types of environments, it has a higher distribution. A factor that increases the abundance and distribution is the mosquito fish's extremely fast reproduction process and rates. Currently, known populations of wild mosquitofish occur in every state and territory except the Northern Territory, and they are found in swamps, lakes, billabongs, thermal springs, salt lakes, and ornamental ponds.Mosquitofish have harmed native fish populations in many ways. By consuming algae-eating zooplankton, they increase the chances of algae blooms in the water, reducing the water quality. They are very aggressive, and tend to attack other fish and nip their fins, leading to infection or death. The decline of the soft spined rainbow fish in Queensland has been attributed to mosquito-fish.
 * __Why is the mosquito fish introduced?__
 * <span class="boldtitle" style="color: #333300; font-family: Arial,Helvetica,sans-serif; font-size: 12px;"> IN THE PAST: Mosquitofish were absent from Australia before they were introduced in the 1920s.
 * __What are some of their adaptations. For each adaptation explain how it improves the mosquito fishes change of survival?__
 * __ What has this done to the ecosystem and how has this influenced the distribution and abundance of the mosquito fish? __

12/06/12 1) Reasons : <span style="background-color: #ffffff; font-family: arial,sans,sans-serif; font-size: small;">1953 was a landmark year for scientists researching an evolutionary explanation for the appearance of life. Stanley Miller reported that he had conducted an experiment which replicated the primeval conditions on Earth and had produced the chemicals that were essential for life to begin. 2) results: <span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;">Amino acids were formed when electric sparks were crackled through a gas mixture. <span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;"> <span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;"><span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;">Urey and Miller provided evidence for the possibility for inorganic substances to produce organic (living) substances.

<span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;">They simulated hypothetical conditions which would be present in the early Earth.

<span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;">They showed how gasses of an anoxic environment, combined with static electricity could form simple organic compounds and Amino Acids.

<span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;">out of 22 amino acids created, 13 where those used to make proteins in living cells.

<span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;">This experiment has been replicated successfully to provide a similar outcome each time.<span style="background-color: #ffffff; display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;">3)  There have been a number of objections to the implications derived from these experiments. Some scientists believe that Earth's original atmosphere might contain less of the methane (CH4) and ammonia (NH3) molecules (reducing molecules) as was thought at the time of Miller-Urey experiment.  But other experiments maintain that the early atmosphere of Earth could have contained up to 40 percent hydrogen - implying a much more hospitable environment for the formation of prebiotic organic molecules. The escape of hydrogen from Earth's atmosphere into space may have occurred at only one percent of the rate previously believed based on revised estimates of the upper atmosphere's temperature. In this new scenario, organics could have been produced efficiently in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean concept. This studies make the experiments conducted by Miller-Urey and others relevant again. Another objection is that Miller-Urey Experiment required a tremendous amount of energy. Although lightning storms are thought to have been very common in the primordial atmosphere, they are not thought to have been as common as the amount of electricity used by the Miller-Urey experiment implied. These factors suggest that much lower concentrations of biochemicals would have been produced on Earth than was originally predicted (although the time scale would be 100 million years instead of a week). Conditions similar to those of the Miller-Urey experiments are present in other regions of the solar system, often substituting ultraviolet light for lightning as the driving force for chemical reactions

4) contributions:

<span style="display: block; font-family: Verdana,sans-serif; font-size: 12px; text-align: left;">