Author Archives: Jay Wong

Think you know your spit? Think again.

How would you feel if you couldn’t taste or swallow your food? How about if speaking was uncomfortable? Having a dry mouth, or not having enough saliva, can cause these unpleasant symptoms.

Most people don’t know all the uses of saliva or the importance of it. Take a listen to our podcast below to see for yourself.

Audio source: Own project group

As was mentioned in the podcast, saliva is necessary not only for digestion of food, but also for tasting, oral health, prevention of bad breath, chewing, fighting germs, preventing tooth decay and communication. Researcher Hal Clark and his team looked into saliva loss resulting in a condition called xerostomia, more commonly known  as dry mouth.

Xerostomia is known to cause a decrease in patient’s quality of life, such as discomfort in speaking and swallowing, pain and possibly anxiety and sleep disturbance. So what causes xerostomia? One of the main causes of xerostomia is linked to radiation therapy for patients with head-and-neck cancers. Radiation therapy consists of targeting X-rays to the area of the tumor (external) or inserting a device near the tumor that emits radiation. Hal Clark and his team investigate loss of saliva due to dose of radiation therapy, or amount of X-rays, for head-and-neck cancer patients.

Source: Own project interview

Source: Own project interview

In this recent study, patients underwent radiotherapy treatment for head-and-neck cancers at the BC Cancer Agency. The researchers collected saliva output from the patients 3 months and one year after radiation therapy. Hal then compared this output with that of baseline, or the saliva output before radiation therapy. Clark found that the average loss of saliva after 3 months was 72% of baseline and the average loss after 1 year was 56% of baseline. To conclude his study, Hal suggested a minimum radiation dose to the main salivary gland to greatly reduce the chances of xerostomia.

In the following video, Hal and his supervisor, Dr. Steven Thomas explain saliva output measurements and radiation therapy treatment.

YouTube Preview Image

Video source: Own project interview

The machine seen in the following video of the patient’s point of view when receiving radiation treatment is the same technology that Hal Clark and his team used for radiation treatment in their study.

Video source: from Vimeo

The level of saliva output affects the patients’ quality of life. Therefore, to reduce the side effect of radiation treatment, researchers are working hard to find the right balance between killing the tumor and maintaining the saliva output of patients. Tasting, swallowing and even speaking would be uncomfortable and painful if you had xerostomia. To put it simply, the fact that efforts are being made to reduce dry mouth shows that our saliva is important. So…don’t forget about your spit!

Surekha Gangar, Seungwon (David) Lee, Jay Wong, Uttara Kumar

Is artificial intelligence going to destroy the world?

One of the hottest topics in computer science these days is the risk of artificial intelligence. Some people think it poses great risk to human beings and will destroy the world, other believe it will greatly improve the quality of life of everyone. In this article I will discuss what are the potential risks and benefits of artificial intelligence.

Stephen Hawking, one of the most well known scientists in the world, recently said in a BBC interview that “The development of full artificial intelligence could spell the end of the human race.” He believes that the natural evolution of human race is not fast enough to complete with the improvement of computer intelligent, especially once computer learns how to redesign itself. In this rate sooner or later computer is going to take over.

Elon Musk, one of the most well known inventor in the world, also warned about artificial intelligence. He said in a recent interview at MIT that AI is “the most serious threat to the survival of the human race.” He urged governments of different countries to provide regulatory oversight to make sure AI won’t be used foolishly. He also donated $10 millions dollars to the Future of Life Institute to research how to keep AI friendly to human.

Quantitatively, how high is the chance for a super intelligence to destroy human? According to a research called Global catastrophic risks survey by the Future of Humanity Institute, there is a 5% chance of human extinction by 2100 by the hand of AI, the highest of any category. According to another survey by Microsoft Academic Search, the median year by which machines can carry out most human professions as least as well as human with 10% confidence is 2024, and with 90% confidence is 2070.

Source: Deviantart

So should we all work to shut down AI research for the humanity? Not necessary. Because even if computer become superior to human, there is no reason now to believe that it will be hostile to human. May be it will be neutral to us and do their own thing, or may be they will be friendly to us and do all of our work like in the movie WALL-E. We just don’t know the answer now. But what we know is that there are some more urgent matter for human to deal with, such as pollution, nuclear weapons, global warming, and diseases like Ebola. AI should not pose a treat to humanity at anytime soon.

By: Yiu Leung Wong

Should you buy a Hydrogen or electric car for the environment?

If you are looking to buy a new car and want to protect the environment, you have two exciting new choices to power your car: Hydrogen fuel cell and battery electric. they are both considered as “green” and can save you money in the long run. So which one should you buy?

Fuel cell car. Source: Wikipedia

Fuel cell car. Source: Wikipedia

What is hydrogen fuel cell car?

There are several types of fuel cell cars but they all work in similarly. It has a cathode, anode and electrolyte that allow electrons to pass through. It works like your AAA batteries except it uses hydrogen as fuel. It has no emission and the only byproduct is water that you can drink! (If you are really thirsty)

Electric car. Source: Wikipedia

Electric car. Source: Wikipedia

What is battery electric car?

Battery electric cars usually use battery Lithium ion battery to store the electricity. The first electric car was invented 130 years ago but it wasn’t until recently that we have technology to mass produce these vehicles. Like hydrogen fuel cell cars, it has no emission so they don’t produce any pollution at the tailpipe.

Hydrogen fuel cell vs Battery efficiency comparison. Source: Wikipedia

Hydrogen fuel cell vs Battery efficiency comparison. Source: Wikipedia

Green comparison

According to a study by Stephen and James Eaves of Arizona State University, battery electric cars are much more efficient than Hydrogen fuel cell cars. To supply 60kWh to a hydrogen fuel cell car, 202 kWh has to be produced from power plants, while only 79 kWh is needed for battery electric cars. The main reason is that the Li-ion battery has a 94% efficiency, while hydrogen fuel cell has only 54%. The findings is similar from another study by Tesla motor (see picture above).

On the other hand, producing Hydrogen is very energy intensive. The most common method is called steam-methane reformation, it involves mixing natural gas with high temperature steam to produce Hydrogen, Carbon Monoxide (toxic) and Carbon Dioxide (greenhouse gas), while the electricity for electric cars can come entirely from renewable sources. For example, according to Tesla Motors, all of their super chargers will be supplied by solar power.

All in all, Hydrogen is only a means to store energy instead of a energy source. Considering the low efficiency and the use a nonrenewable natural gas, electric battery cars seems to be a better choice for your next car.

Yiu Leung Wong

The Imitation Game. First history of computer hacking.

I am sure we have all heard about the hacking Sony Pictures Entertainment. Thousands of emails and personal information of Sony’s employees were released online. While the hackers call themselves to be “Guardians of Peace” or “GOP”, the United States officials claim the hackers came from North Korea and the attack was a response to the release of the film “The Interview”, an accusation that Kim Jong-Un denied. How safe is your computer? I think is it a good time for us to take a look at the history of computer hacking and security.

Naval Enigma machine with 4 rotors. Source:

Naval Enigma machine with 4 rotors. Source: Flickr

The earliest computer hacking is believed to be the cryptanalysis of the Enigma machine. Enigma machine was a cipher machine used from the 1920s to the WWII, mostly by the Nazi Germany. The earliest model has 3 rotors, which means the scrambler could be set in 26 x 26 x 26 = 17576 ways.

The first major breakthrough came from Marian Rejewski. The 27 years old Polish mathematician worked for the Polish Government in the early 1930s to break the Enigma machine. Using permutation group theory, he successfully worked out the logical structure of the machine.

Marian_Rejewski. Source: Wikipedia

Marian_Rejewski. Source: Wikipedia

Unfortunately for the Poles, he Nazi soon figured out their system has been hacked. They made several modifications to the system including increasing the number of rotors from 3 to 5, which increased the scrambler to 26 x 26 x 26 x 26 x 26 ways. Given the situation in Poland at that time, the Polish Government could not supply Rejewski with the resources he needed to break the new system.

The Enigma machine remained unhackable until 1939, when the 27 years old English mathematician Alan Turing started working for the GC&CS to hack the Enigma. Based on Rejewski’s works and the vast resources committed by the UK Government, Turing designed the “British bombe”, an electromechanical device that can decipher German secret message during the WWII. By 1945, all German can be decrypted within a day and it gave out all their plans to the Allied and turned the tide of the war.

Alan Turing. Source: Wikipedia

Alan Turing. Source: Wikipedia

If you are interested in knowing more about Alan Turing and how his work, you can check out the historical drama “The Imitation Game” starring Benedict Cumberbatch and Keira Knightley.

Blog by: Yiu Leung Wong