Category Archives: Latest research

The Toba catastrophe

If you trekked through the mountains of northern Sumatra you might see one very long, serene lake and a sizable oblong island in its middle. The whole thing looks very peaceful until you realize it came to be through a cataclysm of unimaginable proportions.

NASA Landsat image of lake Toba

Around 74,000 years ago in those mountains, a supervolcano was brewing world changing fires that erupted suddenly and violently.

Around 2800 km³ of material was released in an outpouring of hot gasses and volcanic ash that wreaked havoc on an area of approximately 20000 km² around the volcano. This means that an area the size of modern day Slovenia was vaporized, since the temperature of these initial volcanic ejections can reach upwards of a 1000 °C. Ash deposits are found today as far away as the eastern parts of Africa.

Scientists say that a global winter ensued which devastated human populations around the

Location of lake Toba

world, leaving only a few surviving groups in the denvse forests of Africa. Investigations of the human genome have revealed that modern humans within Africa possess much higher genetic diversity than do humans outside of Africa. Evidence from studies of mitochondrial DNA suggests that humans passed through what is known as a genetic bottleneck: a profound decrease in genetic diversity and a fall in the total human population to a few thousand breeding pairs. This is known as the Toba catastrophe theory.

In recent years, more evidence and more precise dating of the eruption timeline paints a different, more interesting picture. Some researchers posit that human beings didn’t just survive, but even thrived after the eruption. We have found ancient tools on African coastlines both above and below the layer of ash deposited by Toba. Interestingly, a greater number and diversity of tools seem to be found after the explosion.

The climate data is complicated. Studies of ice cores reveal that the earth cooled drastically right after the eruption and there followed several years of lower precipitation. But other data suggest that certain species of plants recovered quickly after the event, and fossil evidence indicates that orangutang populations close to the area didn’t drop much either.

Scientists now believe that Toba didn’t release a huge amount of sulfuric acid aerosols as compared with other volcanoes, which contribute significantly to the cooling effect. The chemical composition of the magma might have been such that proceeding winter was substantially less intense, and it is theorized that a lot of water vapor might have been released which actually would have counteracted the cooling effect.

The mystery is far from solved. A recent 2021 study looked at the effect of the eruption on the ozone layer, and concluded that it would have made possible for a lot of dangerous UV light to reach the surface of the earth, killing off a lot of humans in the process. Then there is the glaring observation that Neanderthals went extinct only 30000 years ago, long after Toba.

So, there are a lot of unknowns. The only thing we know for certain is that earth will see another Toba at some point in the future, and the fallout could be much, much worse.

Population growth: limited by pesticides?

The United Nations (UN) forecasts the world population to reach 9.3 billion by 2050. According to them, a 60% increase in food production will be required to sustain the population.

Solution: increasing pesticide use.

Unsplash Photo by @Arjun MJ (Ernakulam, Outdoors)

Unsplash Photo by @Arjun MJ (Ernakulam, Outdoors) Unsplash

Pesticides are chemicals that repel or kill weeds and organisms that affect plant growth.

The United States first introduced pesticides in the 1930s (during the Great Depression when the population was 2 billion) because of their considerable increase in yields. Since then, according to the World Health Organization (WHO), over 1000 types of pesticides are used globally today.

Many people stand by organic products, which use minimal pesticides. There are several reasons why people opt out of consuming products grown with pesticides:

Many synthetic pesticides cannot be broken down by humans or animals. Because of this, they bioaccumulate (simply substances that become concentrated in living organisms) as body fat.

Pesticides also pose a huge threat to aquatic ecosystems. They contaminate ground and freshwater supplies used by wildlife, livestock, crops and people.

In 2020, Boedeker et al in the BMC Public Health Journal, estimated about 385 million people annually get pesticide poisoning.

These are only three reasons why people don’t like pesticides, but there are many more.

With that said, pesticides were first introduced to solve an issue in 1930 – an issue that will soon present itself again: food shortage.

There’s an interesting theory called the Malthusian Trap, which describes how increased agricultural production as a result of advanced agricultural techniques increases the population. But with a greater population, there’s a greater need for consumption, and that strains the food supplies.

Based on a 2017 study of European farming systems, if pesticides were removed from agricultural practice, there could be a 78% loss in fruit production, a 54% decrease in vegetable harvest and a 32% loss in grain yields.

Pesticides provide greater food output, increase farmers’ earnings, improve practice, prevent diseases, and allow cultivation in areas that would otherwise be uncultivable.

Simply, they allow farmers to grow more food on less land, raising yield.

According to a 2005 study by CropLife Foundation, without fungicides in the US, fruit and vegetable yields would decrease by 50-90%. For perspective, 40.3% of Canada’s fruit is imported from the US. This is similarly the case in Mexico, South Korea, and Japan, all countries with high populations. Without pesticides, these countries would experience significant food shortages due to their reliance on the US and their pesticides.

Should cigarettes be abolished in Canada?

Smoking tobacco has been prevalent in Canadian communities for a very long time. Indigenous groups in Canada have been known to use tobacco to smoke for thousands of years. Canadians have been smoking cigarettes since the early 19th century. As time has advanced so have our smoking habits. In 2020 the University of Waterloo conducted a smoking prevalence survey where they concluded that 3.2 million Canadians (approximately 10.2% of the entire Canadian population) actively smoke cigarettes. The current trend in cigarette usage has seen a decrease in cigarette usage over the past 20 years. However, despite the decrease, some people feel that cigarettes should be banned altogether.

Common Cigarette

Tobacco use continues to be the leading cause of preventable illness and death in Canada. Over 48,000 Canadians die from tobacco use every year. Smoking legislation has already come a long way since the 19th century. Smokers would argue abolitions is an extremely drastic change however it is important to remember that it was only just over ten years ago that smoking with children in the car was legal. If a smoker was told that they weren’t allowed to smoke in a bar in the early 21st century they most likely would have gone ballistic believing that it is a complete infringement on their rights. Cigarettes are also a major cause of fires in Canada. From 2012-2015 11% of all outdoor fires were deemed to be caused by cigarettes that were improperly disposed of.

Wildfire prevention icon “Smokey the Bear”

In Canada, the cigarette and tobacco economy is one that puts roofs over people’s houses and food in their children’s mouths. There are over 2,300 Canadians working in the cigarette and tobacco manufacturing sector as of 2023. Economics is not the only reason abolition would be the wrong approach. Considering the health of current smokers is extremely important. Out of the 3.2 million Canadians that actively smoke cigarettes 2.6 million of them are daily smokers. If these people can no longer smoke their cigarettes they can experience serious withdrawal symptoms. Feelings of high anxiety, depression, and lack of sleep can severely impact a person’s mental health. Many people believe that being able to buy and consume cigarettes is their human-born right. A right that should not be infringed upon by the government. It does not take a smoker to not want to have freedoms of choice to be limited by the government.

Nanocrystals: The Science Behind Creamy Plant-Based Ice Cream

Ice cream lovers, get ready to indulge in a whole new level of creamy goodness! The secret ingredient? Nanocrystals.

These tiny particles, smaller than the width of a human hair, have the potential to revolutionize the world of vegan ice cream. Typically less than 100 nanometers in size, they can be made from a variety of materials, including cellulose, starch, and lipids. And here’s the exciting part: they can make vegan ice cream creamier than ever before!

Figure 1. Vegan vanilla ice cream. Source.

Traditionally, guar gum and locust bean gum (LBG) are the most commonly used stabilizers in ice creams. Recent research, however, suggests that cellulose nanocrystals (CNCs) may provide a more effective alternative. CNCs play an important role in improving the texture of plant-based ice cream by preventing ice crystal formation. This is due to nanocrystals’ unique properties which prevent them from growing larger. This results in a smooth and creamy texture comparable to traditional ice cream that consumers with dietary restrictions can enjoy.

But how do nanocrystals work their magic? The answer lies in the physics of freezing. When the water molecules in ice cream freeze, they can form large ice crystals. These large crystals, with diameters larger than 50 μm, impart a grainy texture to ice cream and can make it less creamy. Nanocrystals, on the other hand, can prevent this by enclosing the ice crystals in a protective shell, slowing their growth and keeping them small.

Figure 2. Ice growth kinetics of 0.5% CNCs, guar gum, and LBG in 25% sucrose solutions. Adapted from source.

Figure 2 shows that CNCs at 0.5% concentration can completely stop ice crystal growth after 72 hours. This is a significant finding because the same concentrations of guar gum and LBG had different effects. In the presence of CNCs, the final ice crystal size was approximately 37 μm, which was smaller than the final crystal size in the presence of guar gum and LBG. These findings show that CNCs can be a more effective stabilizer than traditional ones, as they can prevent ice crystal growth and result in smaller ice crystal sizes.

Smaller ice crystals can improve the creaminess, smoothness, and mouthfeel of ice cream.

It’s amazing how such small particles can have such a big impact on the quality of plant-based ice cream. Take a moment to appreciate the incredible chemistry happening in your bowl the next time you enjoy a scoop of your favourite non-dairy treat.

~ Vivian Hou

From catnip to bug spray

Researchers from Iwate University in Japan have published a new paper that explains one aspect of the intriguing response cats have to catnip. The paper, published on June 14th 2022, shows that chewing catnip leaves maximize the release of organic compounds and repels insects. Tamako Miyazaki, who led the research, hopes that the work will pave the way for development of new insect repellants.

A photo of a domesticated cat eliciting a behavioral response to catnip. Source

Catnip is a non-toxic plant in the mint family and it has been long known to elicit several responses in cats. And, it’s not just domesticated cats that are affected, catnip induced behavior has been seen across the feline family including leopards, cougars, tigers, and lions.

Figure 1: Effect of leaf damage on the airborne emission of nepetalactone. Data adapted from Miyazaki et al.

The behavioral response which includes rolling, licking and chewing is seen in two thirds of all felines. The prevalence of these responses led Miyazaki and his team to believe there was a biological importance of the behavior.

Miyazaki and his group have previously identified nepetalactone as the compound responsible for triggering the behaviors.

Nepetalactone is a iridoid compound that is present in high concentration in several plant species including catnip. The group’s previous work, published in 2014, showed that nepetalactone had a strong insect repellant effect. The behavioral response of rolling resulted in the transfer of nepetalactone to the cats fur and provided protection from insect bites.

Following on from this study the team turned there attention to why cats are often seen chewing catnip. Considering that this behavior was also linked to insect repellence the team began by measuring the airborne emission of Nepetalactone from intact and manually damaged leaves. The manual damage was intended to simulate the effects that chewing had on the leaves.

The results, shown in figure 1, was a 20 fold increase in nepetalactone emission in the manually damaged group. When tested on mosquitos, the damaged leaves showed a much greater repellant effect than intact ones. The research group also found that leaf damage affected the cat’s response duration. On average, the studied cats responded to damaged leaves 6 minutes longer than were presented with intact leaves.

The researchers propose that chewing the catnip leaves is an important evolved response that maximizes the amount of airborne nepetalactone. When combined with rolling, the behavior maximizes the protective qualities of catnip and offers a significant benefit to cats.

The paper concludes that there maybe something to be learnt from catnip. Specifically, further studying into the structure and synthesis of nepetalactone may lead to new kinds of insect repellents. While more studies are needed to assess the effectiveness of such a use one thing for sure is that it would have the seal of approval from cats.

Breaking Down Plastic, One Worm at a Time

A 2022 study by Sanluis-Verdes et al. has found that wax worm saliva is able to break down plastic in just a few hours.

The researchers collected saliva from Galleria mellonella worms and applied it to polyethylene (PE) films. After a few hours, the films had visibly deteriorated and analysis of the films determined that the plastic had oxidized and released additives, evidence that it had degraded.

Credit: Catherine Sheila

Generally, plastics require decades or even centuries to completely degrade through natural exposure to the environment. Because of humanity’s high consumption of plastic, simply dumping them in landfills or waterways only leads to an accumulation that smothers habitats and leaks toxic substances into the soil and water.

This makes finding a safe and quick way of breaking down plastic crucial for sustainable waste management.

Scientists in recent years have been particularly interested in biodegradation, in which naturally-produced enzymes from bacteria, fungi, or animals are used to decompose plastic.

However, scientists have only identified a handful of enzymes that are capable of this, and these enzymes still require years to degrade plastic. They are unable to accomplish the first step of degradation – oxidizing the polymer – and still rely on exposure to UV light and other environmental factors to do it, which usually takes years.

Currently known process of plastic degradation. Credit: Rebecca Yang

Sanluis-Verdes et al.’s experiment demonstrated that the enzymes in wax worm saliva are in fact able to accomplish this crucial step under normal physiological conditions – room temperature, neutral pH, typical background levels of UV – in just a few hours rather than years. The researchers identified an increased presence of ketones in the PE after only applying the saliva a few times, proof that it had been oxidized by the enzymes alone.

The researchers also tried to identify the enzymes responsible. They were able to pick out two enzymes in the saliva that had a significant effect on PE degradation. Until now, it was believed that bacteria in the gut of wax worms were primarily responsible for plastic degradation, but this discovery indicated that it was the wax worms themselves that oxidized and broke down PE enough for it to then be completely decomposed by bacteria. The researchers also noted that the two enzymes were functionally different from known bacterial enzymes. This suggests that there may be other methods of biodegradation than what is currently known for bacteria.

The exact mechanism will require further studies to determine. If this can be identified and if the enzymes involved can be easily extracted or mass produced, using the enzymes found in wax worms may become a feasible way to naturally and quickly manage plastic waste.

Blue Light – A Propagated Myth!

Unsplash Photo by Lukas Blaskevicius (Editorial, Technology) Unsplash

Device users are not a risk of eye damage due to blue light emitted from their devices, but they may be at risk of poorer sleep.

In 2019, Director Dr. David Ramsey of Ophthalmic Research at Lahey Massachusets Hospital and his study maintained that “many retail stores have ambient illumination twice as great…as [ones] iPhone, [and that] the sun yields illumination ten times greater!”

Light sources such as incandescence (light bulbs) and LEDs emit a broad spectrum of light, namely 400 to 700 nanometers (nm). Blue light is in the 400 to 450 nm range, carrying more energy than red light, raising concern.

Our retinas regularly absorb blue light emitted by the sun. For roughly 300,000 years, humans have sustained minor to no retinal damage: if it were damaging, we would have evolved optically blind.

Device intensities are much less than the sun and are regulated by manufacturers using light filters.

In 2019, CBC News conducted a Marketplace undercover investigation to debunk the concerns. In addition, Dr. SUNIR J. GARG, American Board Ophthalmologist and clinical researcher, addressed the myth.

“Why you don’t need blue light lenses: Hidden camera investigation (Marketplace)” A 2019 CBC Interview with Dr. SUNIR J. GARG, American Board Ophthalmologist, about why blue light glasses are unnecessary. Youtube

However, in the Harvard study, Dr. Ramsey adds that using devices late at night mimics sunlight, restraining melatonin production, a sleep-inducing hormone. This stimulates your circadian clock (your body’s 24-hour sleep clock), tending to delay your sleep cycles, disrupting your sleep, and increasing drowsiness the following morning.

By stopping use of electronic devices 30 minutes before bed, you can increase REM (deep-stage sleep), reduce morning drowsiness, and maintain a consistent circadian rhythm, which in itself has its own benefits.

In short, research before propagating a supposed “scientific claim” and reduce your screen time before bed.

~ Octavian Turner

Enzymes – A Solution in the War Against Plastics

It should not be a surprise to people that it can take over 500 years for UV radiation – light from the sun to break down a piece of plastic. But what if there is a faster way to break down single-use plastics?

Researchers at the University of California, Berkeley invented a new way to decompose consumer plastics in a short amount of time, simply with heat, water, and nano-dispersed enzymes.

Plastic waste covering the shoreline. Source

UC Berkeley professor Dr. Ting Xu and her research group developed a nanoscale enzyme that can eat away at the polymers in plastics. These nanoscale polymer-eating enzymes can be embedded into plastics during manufacturing. The enzymes were wrapped around plastic resin beads. These beads are melted and can be manufactured into single use consumer plastics. To prevent the enzymes from activating when not required, a random heteropolymer (RHP) coating is applied to hold enzymes without restricting the flexibility of tensicity of the plastics.

Xu likened this process to organic composting. By adding water and heat, the RHP polymers is removed and starts eating away the polymers into smaller subunits.

The research conducted by Xu and her group found that the enzymes took about a week to degrade most of the plastics. Polylactic acid (PLA) and polycaprolactone (PCL) based plastics embedded with nanoscale polymer eating enzymes are able to break down the polymer chains into smaller molecules, such as lactic acid.

Plastic cups made from biodegradable plastics. Source

It is clear there is still more research needed in this field. Currently, Xu is developing other modified RHP-wrapped enzymes that can stop the degradation process at specific points in it’s degradation so that the polymers can be recycled into new plastics.

“[Humans] are taking things from the Earth at a faster rate than we return them,” said Xu. “Don’t go back to Earth to mine for these materials, but mine whatever you have, and then convert it to something else.”

As consumers, we can play an important role reducing our consumption on single use plastics and create a more sustainable environment for ourselves and future generations.

Raymond Tang

A dog’s nose sheds light into a world we cannot see

Dogs are one of the world’s most beloved household pets. However, “man’s best friend” is good for more than just fetching sticks. Dogs are used all over the world for a variety of reasons. Dogs help save lives by being a part of search and rescue teams, bomb squads, and being support animals for those who have medical conditions that can be life-threatening. In the United States, there are roughly 500,000 service dogs helping humans increase their quality of life. A dog’s sense of smell is the key to its utility.

Bomb-Sniffing Dog

Bomb-sniffing Dog

In the past, dogs were mainly used to help hunt or herd livestock. Now certain breeds of dogs can pick up scents that can be linked to seizures, anxiety, or blood sugar. Recently Britt Grogan went into diabetic shock as she was flying cross country. Luckily, she had her service dog Ruxx, who was able to sense her low blood sugar and notify her. “The dog literally saved her life by just telling her your blood sugar is low and you need to wake up and take care of yourself”.

A dog’s sense of smell is one of the most sensitive in the animal kingdom. Certain breeds of dogs have over 300 million scent receptors. Humans cap out at just about 6 million scent receptors in our noses. The way dogs smell is a more refined process than it is in humans. Dogs have a much larger olfactory system than humans which is key to their keen sense of smell. The olfactory system is responsible for the brain to process the sense of smell. The snout of a dog consists of its nostrils, respiratory epithelium, and olfactory epithelium. The olfactory system of a dog consists of a single passageway. It starts from their nostrils connecting to their respiratory epithelium. The scent continues to travel up their snout to their olfactory epithelium which sends signals to their olfactory bulb that connects to their b

rain. The special thing about dogs is that their olfactory bulb takes up a larger part of their brain relative to humans. This allows their brains to process the mountain of information that their scent receptors send to their brains.

: Physiology of a dogs snout.

Physiology of Dog’s snout

It is incredible how useful and sensitive the sense of smell of a canine is. A dog’s nose sheds light on a world we cannot see.

Non-Hormonal Birth Control for Males May be Within Reach

There are currently no non-hormonal birth control pills on the market for females or males, despite these pills likely having fewer harmful side effects than the hormonal birth control methods available for females.

And since males continuously generate sperm while females are born with all potentially fertile eggs, it is easier for scientists to find approaches that reversibly stops sperm production in males rather than risk “spoiling” the non-renewable pool of eggs in females.

Picture depicting the meeting of sperm and egg, which leads to fertilization and pregnancy. Image Credit: deccanchronicle.com

Recently, scientists at the University of Minnesota have found two promising compounds that may become the first non-hormonal contraceptive drugs for males. Testing on mice found that these compounds are effective at reducing sperm count and present no side effects.

The first of these potential drugs is a chemical named YCT529, reported by Dr. Gunda Georg’s group in spring 2022. This molecule was designed to inhibit the function of the protein retinoic acid receptor alpha (RAR-α). Georg’s scientists found that a lack of RAR-α protein in male mice leads to sterilization, but no additional side effects. When YCT529 was orally administered to the mice for 4 weeks, their sperm count was drastically reduced, and the drug was 99% effective in pregnancy prevention.

Line structure of non-hormonal male contraceptive YCT529

Chemical structure of non-hormonal male contraceptive YCT529. Image Credit: Md Abdullah Al Noman

The second drug was reported by the same group of scientists in early 2023 and is named EF-4-177. The target of this molecule is an enzyme named cyclin-dependent kinase 2 (CDK2) which is involved in sperm cell production. The scientists reported an over 45% decrease in sperm count of the mice after 28 days of treatment with EF-4-177.

Currently, a startup named YourChoice Therapeutics based in Berkeley, California is working to market YCT529 to humans soon. According to their website, the company has done testing on dogs and primates with positive results. Their graphics show that after two weeks of treatment with YCT529, sperm levels in dogs drop to zero and primates do not produce enough sperm to be fertile.

If a side effect-free non-hormonal birth control pill for males is introduced to the public, it would expand contraceptive options for those with testicles beyond condoms and vasectomy. As well, it would make it easier for the responsibility of pregnancy prevention to be shared between partners in a relationship.

Hopefully, more research to come will soon make non-hormonal birth control pills for males a reality.

~ Ying Cai