Scientific Scribbles

The voice of UniMelb Science Communication students

UV light: not only make you ugly

Summer is the favorite season for some of us. The summer fantasy is all about ice cream, beach, bikini and sunbaths. But wait for a second, it seems that you have forgotten something very important. Yes, it is your sunscreen.

There are many pieces of research that have shown that UV light can damage our skin and cause sun bourn and photoaging. It is well known that the sunlight contains UV light while bringing the visible light. The UV light is an invisible light which has a short wavelength and high energy. The high content of energy in UV light enables it to damage the DNA of plants, animals and bacteria, therefore is it usually used for disinfection.

Photo by Sai Kiran Anagani on Unsplash

UVA, UVB and UVC
The UV light can be classified as UVA, UVB and UVC depend on the wavelength. UVC which has the shortest wavelength and the largest energy is the most dangerous UV light. Fortunately, we are protected by the ozone layer against 100% of UVC and most UVB. In our daily life, our skin is threatened by the UVB and UVA, but you may not know the difference between them.

UVB ray is responsible for the sunburn. It composes only 5% of the UV light we exposed to, however, it will be strong enough to make you feel itchy, pain and stinging after 1 to 2 hours direct contact. The lucky thing is, UVB is hard to pass through fabrics and glasses. In other words, avoiding direct contact with the sun can easily avoid sunburn.

The lowest energy UV light, UVA ray, is much harder to block compared to UVB and UVC. UVA composes 95% of the UV light on the earth’s surface. It arrives on our skin though direct contact and diffuse reflection, which means even you are under a shade or behind glasses, UVA can reach to you. UVA ray is responsible for the photoaging of the skin, which includes collagen breaking, dilated capillary and melanin production, then followed by wrinkles, rash and tanning. The dull and dry skin is not only about our appearance, but prolonged exposure to UVA rays can also cause the abnormalities of our tissue and therefore accelerate the toxic effect of UVB rays, proved by several experiments.

Protect our skin
Fortunately, we can count on the reliable sunscreens to protect our skin from UVA and UVB rays. The most usual scheme of our sunscreen is either reflecting the UVA and UVB rays, such as titanium dioxide, or absorbing the rays by breaking bonds, such as Benzophenone.

When we walk into a shop and look at the package of the sunscreens, you are able to see the SPF level on it. However, the SPF level only represents the blocking effect of UVB rays, which has nothing to do with UVA rays. For those who do not want as much as wrinkles and dark spots on the skin, you will need to look for the phrase ‘broad spectrum protection’ on the package to ensure the product is also blocking UAV rays effectively.

Stay safe and protected is another theme in summer. When the summertime arrives, don’t forget to bring your sunscreens with you before you are going out.


Hate the “love handle”? Use the “love drug”!

Do you love the “love handle”? Although it has a cute name, you may still try to get rid of it. Recently scientists found that the “love drug” has the potential to help people lose weight. Will it come true?

What is the “love drug”?

It is both a hormone and a neurotransmitter in the brain, academic name “Oxytocin”. The reason for being named “love drug” is that it not only plays an essential role in physiological behaviours which involve “love”, including sexual reproduction, childbirth, and breastfeeding, but also helps people build social bonding like affection and trust.

The “love drug” reduces appetite!

Obese people tend to eat more even when they are not hungry. Their brain has a higher level of reaction when seeing delicious food. This is the inspiration for conducting studies on the relationship between oxytocin and weight loss. If there is one medication that can reduce appetite, then it has the opportunity to help people lose weight!

Will the “love drug” be that medication?

In several studies, scientists used intranasal oxytocin on overweight and obese participants and measured their brain reaction using fMRI. The activity of the regions of the brain involved in eating was lower compared with using a placebo. This result indicated that oxytocin has the potential to reduce people’s desire for food.

Other effects that the “love drug” has

The “love drug” does not only reduce appetite; it helps lose weight in other ways.

Oxytocin has a synergic effect on insulin it improves insulin sensitivity. Insulin is a peptide hormone that regulates the metabolism of carbohydrates, fats, and protein. The positive synergic effect of oxytocin on insulin helps improve the balance of energy intake and consumption, which may result in weight loss.

Besides, oxytocin reduces activation in the hypothalamus. Hypothalamus is an “information processing centre” in the brain. It has two nerve nucleus that help control eating behaviour. Once the activation of the hypothalamus drops, people may not feel hungry quickly.

A study this year also shows that oxytocin reduces alcoholic’s dependence on alcohol. Alcohol is known to have a strong effect on people’s gaining weight. The experiment was conducted on alcohol-dependent rats. The rats showed a reduced addictive behaviour to alcohol, which indicates the oxytocin is a potential remedy for alcohol addiction.

Why don’t we use it now?

Studies on this topic haven’t collected enough evidence. Such a small sample size is not convincing enough. Also, although oxytocin has so many benefits, its adverse effects and side effects can not be underestimated. Therefore, before the drug approved into the market, we should still wait for the strict clinical trials.

There are many reasons for obesity. Even if oxytocin works, it may work only on some of the obese people. The treatment for obesity should better be individualized. Oxytocin will not be the Panacea.

There is also a phycological concern about oxytocin. We have already had experiences that some drugs which were invented for releasing pain or enhancing happiness had an addictive effect, like morphine and endorphins. Oxytocin may also cause a phycological dependence on it if used in the long term.

 

It seems that getting rid of the “love handle” would not be that easy. Losing weight by simply taking medicine may not come true within decades.

 

Reference:

Ding C, Leow MK, Magkos F. Oxytocin in metabolic homeostasis: implications for obesity and diabetes management, Obes Rev. 2019 Jan;20(1):22-40.

Spetter MS, Hallschmid M. Current findings on the role of oxytocin in the regulation of food intake. Physiol Behav, 2017 Jul 1;176:31-39.

Brendan J. Tunstall et al. Oxytocin blocks enhanced motivation for alcohol in alcohol dependence and blocks alcohol effects on GABAergic transmission in the central amygdala. PLOS Biology, 2019; 17 (4): e200642.


How long is a goldfish’s memory?

There is a popular belief that goldfish only have a 3 second memory. But, the humble goldfish may not only have a longer memory than most people think, but may also be far smarter.

If you own a goldfish there’s a good chance it remembers you for longer than 3 seconds. Image by Benson Kua via Flickr

How long can goldfish remember?

Quite a simple experiment conducted by a 15-year-old school boy debunked the theory that goldfish don’t remember longer than a few seconds. When he would feed his pet goldfish he would put a red piece of Lego in their fish tank, and would sprinkle food around the Lego block. At first the fish seemed scared of the block, but after a couple weeks the goldfish learned that the red block meant that food was coming, and would swim straight towards it.

After the goldfish seemed to learn what the block meant, he then stopped using the Lego piece for 1 week. He then re-introduced the block, and the fish swam straight towards it in anticipation of food.

This quite elegant experiment shows that goldfish can remember information for at least a week.

In another experiment researchers trained young goldfish by playing a certain sound during feeding time. These goldfish were then released into the ocean. About 6 months later the researchers played the sound again over a loudspeaker and many of the goldfish returned to where the sound was playing. Again much longer than the 3 second myth would have you believe.

So, a goldfish clearly can remember things for longer than 3 seconds, but are they at all smart?

How smart are goldfish?

If I asked you to name a ‘smart’ animal you would probably say something like a dolphin or a chimpanzee, I definitely don’t think you would say a type of fish. However, scientists think that many fish are smarter than we give credit for.

Many biologists think that fish are actually quite intelligent. A biologist from the University of Edinburgh says that “in many areas, such as memory, the cognitive powers [of fish] match or exceed those of higher vertebrates, including nonhuman primates”

Goldfish have shown that they have an ability to learn and process information. Pet goldfish can distinguish between humans, and often recognise the human that regularly feeds them. Pet goldfish can also seem quite scared of new people, but become more comfortable with their owners over time as they realise they aren’t a threat.

Goldfish have also been taught to do relatively complex tasks like swimming through mazes, or pushing a ball into a net. This means that goldfish not only have the ability to recall information, such as its owner that feeds it, but also has the capacity for more complex processing and cognition.

They may not look smart but goldfish have been trained to perform quite complex tasks. Image by Gexydaf via Flickr

Why do we think that goldfish are dumb?

Many people have this pre-conceived notion that evolution is liner, that fish evolved into reptiles, that evolved into mammals, then primates and then us. So, fish much be less intelligent than all animals that came after it, right? But that’s not really how evolution works. Yes, 400 million years ago there was a prehistoric fish that crawled out of water, which over millions of years eventually evolved in humans. But, fish are not the same as they were 400 million years ago.

Scientists think that fish have evolved over millions of years to remember things like where they can find food, and what a predator does and doesn’t look like – in the same way they recognise their owner is not a threat and will give them food.

So, we really should give goldfish more credit. While they’re definitely not the smartest creatures in the animal kingdom, goldfish are definitely more intelligent than the 3 second memory myth gives them credit for.


Radiation Explained: Chernobyl, Fukushima and …Bananas?

In 1986, Chernobyl Nuclear Power Plant endured the worst nuclear disaster in human history. The accident was caused by a flaw in the power plant reactor.  It was not the design flaw that caused widespread catastrophe though. It was the fuel inside the reactor that caused harm. Even the newer and much safer designs couldn’t prevent the outcomes of the 2011 tsunami in Japan. This natural disaster saw the Fukushima Power Plant destroyed, causing the evacuation of over 100,000 people. We know all too well that the use of nuclear fuel comes with extreme risks due to the fuel’s volatile nature.


Chernobyl is still classified as unsafe, over 30 years later. (Image taken by Ian Bancroft, Sourced from Flickr album: Chernobyl.)

What makes nuclear energy dangerous?

The saying goes that ‘with great power, comes great responsibility’.

All sources of power come with a level of risk. Fire burns, electricity shocks, but nuclear energy harnesses a reaction so powerful that it can destroy entire cities. In the recent Chernobyl mini-series by HBO, nuclear radiation was described to be like bullets. Bullets travel extremely quickly. They can pierce through objects with deadly force. Nuclear energy harnesses the power of atoms splitting. It is the energy released from this process is what makes nuclear radiation like a bullet. Unlike a bullet, radiation doesn’t puncture the skin. These atoms can be absorbed by the human body and cause something known as radiation sickness.


Radiation still seeps out of the ground at rates too high for humans to tolerate for long periods of time. (Image taken by Ian Bancroft, Sourced from Flickr album: Chernobyl.)

What does radiation sickness actually do to the body?

Harmless household items such as kitchen benches and bananas give off low levels of radiation. The human body is able to handle these small exposures without making you sick. Meanwhile, higher levels of radiation cause damage to the cells inside our bodies. A common example of this is sunburn. Sunburn occurs when we spend too much time in the sun. The sun naturally emits UV rays, which are a type of radiation. Mild radiation sickness can have similar symptoms to prolonged sun exposure. This includes burns, nausea and (in more extreme cases) cancer. Similar to the sun, radiation from nuclear power is most damaging when people have long, unprotected exposure to it.

How does nuclear power work?

Nuclear power uses an element called uranium. Like a lot of elements, there are several different kinds of uranium, each with a specific number of neutrons in each atom. These variations of an element are called isotopes. Most uranium that comes out of the ground is an isotope called Uranium-238. Uranium-238 isn’t very radioactive, so it can’t be used as fuel for nuclear power. The type of uranium used for nuclear power makes up under 1% of naturally occurring uranium in the world. This isotope is called Uranium-235. Naturally occurring uranium must undergo a process that increases the amount of Uranium-235, before it can be used in a Power Plant. Uranium-235 atoms can be split, which causes an immense amount of energy to be produced. The process is called fission, and it is this same process that makes atomic bombs so explosive.

 

Why do we use it as an energy source?

Nuclear power is popular because it produces a vast amount of power, so it is a reliable source of energy for large populations. Nuclear power also has zero direct carbon dioxide emissions.This makes nuclear power an effective energy option that may help to lessen the impacts of global warming.

 

To learn more about nuclear energy, click here.


Saturn running rings around Jupiter

Remember when scientists decided pluto wasn’t a planet anymore? Sometimes scientific discoveries force us to rethink some of our basic assumptions about the universe. If I asked you “which planet has the most moons?” what would your answer be? Are you sure?

Well, if you said “Jupiter,” you’d be totally, utterly, 100% wrong. But you’d be forgiven for thinking this was the correct answer, since it was what everyone thought before scientists at the Carnegie Institution discovered another 20 moons in orbit around Saturn.

A 400 year rivalry

Ever since Galileo discovered Callisto, Europa, Ganymede and Io, Jupiter has claimed the prestigious title of Most Moons in the Universe.

Galileo spotted these giant satellites using a 20x magnification telescope more than 400 years ago. Since then, as telescope technology has advanced, a total of 79 moons in orbit around the solar system’s largest planet have been found.

Galileo discovered the first non-terrestrial moons in 1610 (public domain)

With the discovery of the 82nd moon orbiting Saturn, Jupiter’s long reign as Master of Moons has finally come to an end. A team of scientists led by Scott S. Shepphard announced the discovery on Monday October 7, 2019.

Last but also least

Since the larger moons are easier to see from Earth, the more recently a moon is discovered, the smaller it tends to be.

The moons discovered by Galileo are roughly the size of Earth’s moon – about 3,400 km in diameter. For comparison, that’s close to the distance between Melbourne and Perth.

The four “Galilean moons” of Jupiter (NASA, public domain)

On the other hand, most of the 20 newly discovered moons around Saturn are only 5km in diameter – roughly the distance between Carlton and Richmond.

The Carnegie Institute team also recently discovered two moons orbiting Jupiter in 2018, both of which were a breezy 2km in diameter – about the length of a pleasant afternoon walk!

Mountain view

The moons were discovered by Shepphard and scientists from UCLA and University of Hawaii using the Subaru (すばる望遠鏡) telescope – an 8.2m optical telescope sitting 4,139 m above sea-level on the summit of Hawaii’s Mauna Kea.

The Subaru telescope in Big Island, Hawaii (CC BY-NC-SA 3.0, Denys)

Is the tallest mountain island in the world, and was chosen as a site for an observatory for its dry atmosphere, which helps to reduce interference in the infrared signals which Subaru uses to capture images of the stars.

Saturn wins, for now…

That leaves the current score at 79 – 82, in Saturn’s favour. So the next time somebody asks you which planet boasts the most moons – you know the answer!

The discovery is a timely reminder that we need to be paying attention to the latest news from our busy astronomer friends. Who knows? Perhaps one day soon 3 or 4 more of Jupiter’s tiny moons will be discovered and the tables will turn once again!


Number of posts found: 3294

Authors