Term 2 Self-directed and Independent Research Learning

Term 2: Self-directed and Independent Research Learning

Radioactive Isotopes:

Using the 5 W and 1 H as the thinking framework, do a research on some of these radioactive

isotopes can be used in treatment of tumor in thyroid gland.

Who: The people involved in this research

What: The ideas, problems, events

When: Time when this treatment method started

Where: Started in which country

Why: The causes, reasons, results or conditions

How: How it began or work

Iodine is made into two radioactive isotopes, I-123 and I-131, that are commonly used in patients with thyroid disease. A radioactive isotope (RAI) is a substance that gives off radiation. RAI is given by mouth, in pill or liquid form. RAI is then absorbed by the thyroid cells and can be used to diagnose or treat thyroid problems.

I-123 is most frequently used to take pictures of the thyroid gland. The dose of I-123 is small, and because of its short half-life (about 12 hours), there are fewer precautions that need to be taken. The disadvantage is that the small dose is not as sensitive at detecting thyroid tissue compared to the larger dose of I-131 that is used for treatment.

I-131 is commonly used to treat thyroid disorders, such as hyperthyroidism, through RAI ablation (medically destroying the thyroid gland without surgery). In addition, large doses of I-131 are used to destroy thyroid cancer cells, which are killed after absorbing the dose of radioactive iodine

No matter how expert the thyroid surgeon is, the majority of time there is a small amount of thyroid tissue that remains after the removal of thyroid gland. For patients with a diagnosis of thyroid cancer, we use RAI to destroy remaining thyroid cells after surgery, a treatment called remnant ablation.

For patients who need RAI treatment, we only give additional doses of RAI after we determine that the thyroid cancer is growing and if the remaining cancer cannot be surgically removed. There are a number of different radiologic studies and nuclear medicine studies that can be used to find remaining thyroid cancer. These techniques will be discussed with you and your child if and/or when necessary.

Prior to receiving RAI for treatment of thyroid cancer, patients must be placed on a low-iodine diet and their TSH level must be increased. Low-iodine diet: Patients are placed on a low-iodine diet two weeks prior to receiving radioactive iodine. This makes them iodine-deficient and increases the chance that the thyroid cells will absorb the radioactive iodine dose. A high thyroid-stimulating hormone (TSH) level increases the ability of thyroid cells to absorb iodine. TSH is secreted by an area of the brain called the pituitary gland, which tightly controls the amount of hormone produced by the thyroid gland. Advantages and disadvantages of THw vs. rhTSH can be discussed with your provider.

All female patients of child-bearing age must have a pregnancy test before they are given a treatment dose of RAI. RAI, whether I-123 or I-131, should never be used in a patient who is pregnant or nursing. 

Video:

Sources:
http://www.chop.edu/service/pediatric-thyroid-center/radioactive-iodine/
Google Images
http://www.youtube.com/watch?v=zMeW0sx0bXc

Carbon Nanotubes

Carbon nanotubes are tubular carbon molecules that have properties that make them potentially useful in
nanotechnology. They exhibit unusual strength and unique electrical properties, and are extremely efficient
conductors of heat.

A nanotube is a structure similar to a fullerene, only the carbon atoms are rolled into a cylinder instead of a
sphere; each end is capped with half a fullerene molecule. They are only one nanometer wide (on the order of one ten-thousandth the width of a human hair), and their length can be millions of times greater than their
width.

A team of Stanford engineers has built a basic computer using carbon nanotubes, a semiconductor material
that has the potential to launch a new generation of electronic devices that run faster, while using less energy, than those made from silicon chips.

Taken from:
http://encyclopedia.kids.net.au/page/ca/Carbon_nanotube
http://phys.org/news/2013-09-stanford-carbon-nanotube-technology.html#jCp

Discussion:
1. Compare the structure of the nanotubes to the structure of other carbon compounds like diamond and
graphite.
2. Discuss the future applications of carbon nanotubes.

1. Buckytubes are single-wall carbon nanotubes, in which a single layer of graphite - graphene - is rolled up into a seamless tube. Graphene consists of a hexagonal structure like chicken wire. For example, carbon-carbon bonds (the wires in chicken wire) can be parallel or perpendicular to the tube axis, resulting in a tube where the hexagons circle the tube like a belt, but are oriented differently. Alternatively, the carbon-carbon bonds need not be either parallel or perpendicular, in which case the hexagons will spiral around the tube with a pitch depending on how the tube is wrapped. Carbon is unique in its ability to form a close to ten million different compounds. Carbon forms a stable structure with itself in many triangular variations. Graphite is a Non-metallic, dull, crystalline form. Diamonds are a Glossy, crystalline form. Carbon has been used in its elemental forms in industry as early as when Thomas Edison used it to make filaments for his light bulbs.

Graphite:

Diamond:

2. Individual CNT walls can be metallic or semiconducting depending on the orientation of the lattice with respect to the tube axis, which is called chirality. MWNT's cross-sectional area offers an elastic modulus approaching 1 TPa and a tensile strength of 100 GPa, over 10-fold higher than any industrial fiber. MWNTs are typically metallic and can carry currents of up to 109 A cm−2. SWNTs can display thermal conductivity of 3500 W m−1 K−1, exceeding that of diamond.

As of 2013 carbon nanotube production exceeded several thousand tons per year, used for applications in energy storage, automotive parts, boat hulls, sporting goods, water filters, thin-film electronics, coatings, actuators and electromagnetic shields. CNT-related publications more than tripled in the prior decade, while rates of patent issuance also increased. Most output was of unorganized architecture. Organized CNT architectures such as "forests", yarns and regular sheets were produced in much smaller volumes. CNTs have even been proposed as the tether for a purported space elevator.

Sources:

http://www.azonano.com/article.aspx?ArticleID=983
Google Images
http://www.arch.mcgill.ca/prof/sijpkes/arch374/winter2002/psbmonro/
http://en.wikipedia.org/wiki/Potential_applications_of_carbon_nanotubes

Next Generation Broadband

The Next Generation Nationwide Broadband Network (Next Gen NBN) is the wired network of the
Next Generation National Infocomm Infrastructure (Next Gen NII), which seeks to transform
Singapore into an intelligent nation and a global city, powered by infocomm.

This is made possible with the fibre optics buried deep under the sea forms the backbone of the
World Wide Web. These fibre optics routinely send vast amounts of information as light signals
which travel along this information super highway.

http://www.ida.gov.sg/Infocomm-Landscape/Infrastructure/Wired/What-is-Next-Gen-NBN

Discussion:
1. Compare the use of fibre optics to the traditional way of transmitting information and signal.
2. Singapore is building its Next Generation Nationwide Broadband Network using optics fibre.
What is its economic and social impact on Singapore.

1. Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals. Due to much lower attenuation and interference, optical fiber has large advantages over existing copper wire in long-distance and high-demand applications. However, infrastructure development within cities was relatively difficult and time-consuming, and fiber-optic systems were complex and expensive to install and operate. Fiber-optic communication systems have primarily been installed in long-distance applications, where they can be used to their full transmission capacity, offsetting the increased cost. The price for rolling out fiber to the home has currently become more cost-effective than that of rolling out a copper based network. Since 1990, when optical-amplification systems became commercially available, the telecommunications industry has laid a vast network of intercity and transoceanic fiber communication lines. By 2002, an intercontinental network of 250,000 km of submarine communications cable with a capacity of 2.56 Tb/s was completed, and although specific network capacities are privileged information, telecommunications investment reports indicate that network capacity has increased dramatically since 2004. Microwave radiation can be used to transmit signals such as mobile phone calls. Microwave transmitters and receivers on buildings and masts communicate with the mobile telephones which are in their range. Radio waves are used to transmit television and radio programmes. Longer wavelength radio waves are reflected from an electrically charged layer of the upper atmosphere. They can reach receivers that are not in the line of sight because of the curvature of the Earth’s surface.

2. The advantages and benefits that telecommunication can bring to education, commercial, medical and governmental activities are too numerous to mention, suffice to say that its expansion plays an important role in the economic and social development of a country. One important benefit of a penetrative telecomm infrastructure is that it can enhance instant communication between Singapore and people in distant places around the globe. In other words, increasing the number of phone lines per inhabitant, teledensity, can help put us on the world map through enhanced domestic and global trade. This will pave the way for a stronger economy. Improving the telecom infrastructure will reduce the cost of local and international phone calls to and from Singapore enabling us to join the international community. Optical fibre is a social need for Singapore. It has impacted us greatly.

Sources:
http://en.wikipedia.org/wiki/Fiber-optic_communication
Google Images
http://www.bbc.co.uk/schools/gcsebitesize/science/21c/radiation_life/waves_communicationrev1.shtml
http://www.betelco.com/bd/bdstel/icee.pdf

Critical Review:

Everyone should know of the AIDS (Acquired immunodeficiency syndrome), caused by the HIV virus. And, the moment someone has contracted AIDS, it is known that the person would have a weakened immune system which may cause him to be more prone to other viruses. Many people know that AIDS cannot be cured, and victims would have to live with it forever. However, I was amazed when I came across a recent article which shows that scientist are one step closer to finding a cure for AIDS.

A cure for AIDS has got a step closer after scientists found that a common cancer drug can purge the disease as it lies dormant in the body. Current treatments are effective at reducing levels of the disease in the bloodstream - but a drug that can 'knock out' the disease when it lies dormant is thought to be key to a cure.Tests on eight HIV-positive men found that the drug was highly effective in 'unmasking' the hidden reservoirs in the body - which the researchers say is a vital step towards eradicating HIV from the body. This work provides compelling evidence for a new strategy to directly attack and eradicate latent HIV infection. The existence of persistent reservoirs of dormant HIV in the immune system that are not attacked by anti-AIDS drugs is believed to be a major reason why infection reemerges once patients stop taking their medication. The disruption and clearance of these reservoirs is critical to finding a cure for AIDS.

A cure for AIDS has got a step closer after scientists found that a common cancer drug can purge the disease as it lies dormant in the body.

Also, many researchers believe the best hope for eradicating HIV infection lies in combining antiretroviral treatment with drugs that flush HIV from its hiding places. The idea is to force resting infected CD4 cells to become active, whereupon they will start producing new HIV particles. The activated cells should soon die or be destroyed by the immune system, and the antiretroviral medication should 'mop up' the released HIV. Chemical agents used to activate resting cells are called antilatency agents.

Early attempts to employ this technique used interleukin. This chemical messenger tells the body to create more CD4 cells and to activate resting cells. Researchers who gave interleukin-2 together with antiretroviral treatment discovered they could no longer find any infected resting CD4 cells. But interleukin-2 failed to clear all of the HIV; as soon as the patients stopped taking antiretroviral drugs the virus came back again.

A computer-generated image of HIV exiting a cell    A computer generated Image of the HIV Virus exiting the cell.

In November 2008, a pair of German doctors announced that they had cured a man, Ray Timothy Brown of HIV infection by giving him a bone marrow transplant. The transplant given as a treatment for leukemia used cells from a donor with a rare genetic mutation known as Delta 32 that confers resistance to HIV infection. Twenty months after the procedure researchers reported they could find no trace of HIV in the recipient's bone marrow, blood and other organ tissues.

In a journal article published in December 2010, the doctors concluded that the patient had indeed been cured of HIV infection. Their evidence showed a successful reconstitution of CD4 T cells at both the systemic level and in the gut mucosal immune system.

However, bone marrow transplantation is too dangerous and costly for widespread use as a cure. Many patients die as a result of chemotherapy or reactions to the transplant, which is usually a last resort in treating life-threatening disease.

Let us watch a video on an interview with Ray Timothy Brown who was the first man cured of AIDS

Reflections:

I feel that AIDS is a life-threatening disease and has to be cured immediately. In 2011, another 461 Singapore residents were newly reported with HIV infection. About 93% of the new cases were males and 7% were females. This brings the total number of HIV infected Singapore residents to 5,306 as of end 2011. 

As of 31 Dec 2011, 2,550 persons are asymptomatic carriers, 1,263 have or have had AIDS-related illnesses and 1,493 have died. I feel AIDS is a disease that has claimed the lives of many and I am certainly very happy to hear that scientist are moving one step closer to finding a cure for AIDS. Mankind is moving one step towards. Although scientists have actually cured one man of the HIV virus, I feel that this is already a great milestone. However, scientists must seek other ways to end the epidemic.

However, not all the responsibility should be put on the shoulders of the scientists. We should also play our part in combating AIDS. Sexual transmission remains the main mode of HIV transmission among Singapore residents. Of the 461 cases reported in 2011, 449 cases acquired the infection through the sexual route, with heterosexual transmission accounting for 46% of infections, homosexual transmission 42% and bisexual transmission 9%. Intravenous drug use accounted for 0.4% of infections. Therefore, in order to stop the widespread of AIDS, we can do our part by not having casual sexual intercourse with others. Currently, prostitution is legal in Singapore. Thus, a good way to stop AIDS would be to stop prostitution and make it illegal. In addition, a heavy penalty or fine can be imposed on prosecutors who break this law. This method would certainly be effective. Thus, if everyone plays a part, I feel that we would be able to combat AIDS effectively and one day, a cure would be discovered.

Sources:
http://www.avert.org/cure-for-aids.htm http://www.dailymail.co.uk/sciencetech/article-2179262/Cure-AIDS-step-closer-common-cancer-drug-purge-dormant-HIV-body.html
Google Images