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Risks of impaired driving

Researcher at Colorado State University stated that 33 out of 100 high school graduates reported they have at least ridden once with an impaired driver.

Vehicle accidents are the leading cause of death for many young adults. The act of adolescents driving while impaired or riding with an impaired driver has become very common, due to consumption of marijuana, alcohol, or other drugs. However, it is more likely that young adults will ride with an impaired driver by marijuana rather than a driver who is drunk.

(credits: http://blog.allstate.ca/new-laws-on-the-way-to-combat-impaired-driving/)

Students who have graduated from high school for one or two years were asked various health-related questions in a study, including questions such as “during the past 12 months, how many times did you ride in a vehicle driven by someone who had been drinking alcohol?” and the question was repeated for marijuana and other drug users too. People who have been driven by an impaired driver was given by 23 percent of marijuana users, 20 percent of drunk drivers, and 6 percent of other drug users.

(credits: http://www.calgary.ca/CSPS/PSC/Pages/Report-impaired-drivers.aspx)

The participants were also asked who the driver was: a friend, family member, unknown person around the same age, or an older relative, unknown-adult. It was more common for people to ride with peers that are impaired compared to older individuals. Riding with an impaired driver enforces this act to be repeated and seen as acceptable. Furthermore, individuals who ride with impaired drivers often become impaired drivers themselves. Therefore, it is important to educate adolescents early on the risks of impaired driving .

 

 

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Posted on March 26, 2018 by in Uncategorized

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New Device Could Help Understand Evolution

Are we closer to overcoming genetic mutations? A recently published paper in Science journal describes a device invented to study the effects of genetic mutations in individual bacterial cells.

The researchers found only one percent of the mutations resulted in cell death, whereas most of non-lethal mutations seemed to have no effect.

Genetic mutations fuel evolution, but they can be detrimental to humans. They are responsible for a range of problems plaguing humanity, like antibacterial resistance to cancer.  Determining the rates at which mutations occur is central to understanding genetic mutations.

Although gene mutation in bacteria have been studied for ages, they have been on large population of bacteria. These tests start by using millions of bacteria which replicate over many days, then the final colony is compared to the starting colony to find the rate of mutations over generations of bacteria.

Bacterial Cells Image courtesy – wikipedia

The problems with this approach is that you can only analyze a small number of samples, and the effects of mutations are an average seen in all the cells. Most lethal mutations are never seen, since those bacterial cells die before replicating to form a colony.

Researchers from institutes across France built a device called a “mother machine” to separate an individual bacterium, observe it replicate, and study its mutations over several generation.

This device was installed with hundreds of tiny tubes that could trap a single bacterial cell at a time. The cell division process was observed with  a microscope and if there was a mistake in genetic replication, it was labelled with a fluorescent tag – a molecule attached to a  biomolecule to track its activity.

The researchers found that all cells had the same likelihood of mutating. One cell was not more inclined to mutate than another cell.

The researchers watched 200 generations of bacteria that  had total of 20, 000 mutations.

Summary of the Effects of Mutation on Bacterial Cells   

Number of mutations observed Percent of all mutations (%)
Lethal mutations (caused cell death) 200 1
Harmful mutations (didn’t cause cell death) 40 0.2
Harmless mutations 19, 760 98.8
Total mutations observed 20, 000 100

Data source- Robert et al., Science (2018)

Only one percent  of the mutations were lethal to the cell, 0.2%  were harmful but did not kill  the cell. The rest of the time, the mutation does not affect the cell.

The bacterial cells were living in controlled environments conducive to cell growth. This means the cells were not exposed to environmental factors  that would result in natural selection. As a result, the researchers couldn’t determine if any of the harmless mutations were beneficial for bacteria’s survival in natural environments.

The researchers are planning to see the effects of surroundings on mutation by carrying out the experiments while changing the environment around the bacteria.

However, a controlled setting without natural selection reveals the rate of mutation inherent to cell replication, which can help scientists understand what drives mutation.

References:

Robert, L.; Ollion, J.; Robert, J.; Song, X.; Matic, I.; Elez, M. Science2018, 359(6381), 1283–1286.

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Posted on March 19, 2018 by in Chemistry in the news, Uncategorized

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Moose Population Analysis – Fewer Yearly Hunters

Animal populations change over time, such is a well-known fact. There are many factors contributing to cause a specie’s population to change, some of these natural and some man-made. Animal populations are often monitored over time and their habitats investigated to find the cause of the population change. Over a period of 28 years, from 1987 – 2014, moose population numbers were counted yearly along with the numbers of licensed hunters and hunter harvest estimates.

The graph below shows that the numbers of yearly hunters decreased over time. However, the population report states that moose populations remained relatively constant over time. This shows that the numbers of hunters does not have too large an effect on the moose populations, and to accurately model the change in moose populations, other factors must also be included, such as food availability, weather/climate, diseases, etc.

Reference: Kuzyk, Gerald W. “Provincial Population and Harvest Estimates of Moose in British Columbia.” Alces, vol. 52, 01/01/2016, pp. 1,

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Posted on March 6, 2018 by in Uncategorized

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Why Biofuels Can’t Replace Transportation Fuels

Agitation regarding rising greenhouse emissions and petroleum costs has drawn focus to biofuels as renewable source of transportation fuel. However, a study published in Angewandte Chemie  argued that crops should not be harvested for biofuel due to their reduced photosynthetic efficiency (percent light converted to stored energy) and annexation of agricultural land from food plants.  

Biofuels require a massive energy input espoused as transportation costs, fertilizer production and agriculture machinery that amounts to 50% of the energy that biofuels contain. The energy investment is extricated from fossil fuels, leading scientists to believe that the net reduction in carbon dioxide emissions from biofuel production is marginal.

Moreover, repurposing arable land for fuel crop harvest will decrease food production thereby inflaming food prices.

Alternative renewable energy such as photovoltaic cells, which are used to generate solar power, are 150 times more efficient at harnessing energy than plants. Moreover, combustion engines powered by biofuels have 20% thermal efficiency compared to electrical engines, which utilize 80% stored chemical energy in batteries.

Hence, harnessing solar generated electricity to charge electric cars is found to optimize land usage 600 times more efficiently than producing biofuels to power internal combustion engines.

The Biofuel Lifecycle Credit source: Wikipedia

Biomass differs from other renewable sources since its energy is stored as chemical bonds in carbohydrates that are broken down to ethanol to power cars.  

Photosynthetic pigments in plants absorb light, and electrons and protons (negatively and positively charged particles) transfer the radiant energy to reactor centres. Subsequent reactions synthesize ATP,  a biological energy carrier, which assimilates carbon dioxide from the air and converts it to carbohydrate.

As a result of biological inefficacies in electron movement, limited reaction rates, and maximal sunlight absorption of 20% by photosynthetic pigments, only 1% photosynthetic efficiency is observed for most plants. Using the yield of biofuel per unit area of land, the photosynthetic efficiency was calculated for various fuel crops.

Photosynthetic Efficiency for Different Fuel Crops Data Source- Sustainable Energy – without the hot air

Given that biomass is a source of carbon, researchers believe that biomass is best utilized for manufacturing chemicals that are synthesized from petroleum. Leftover plant residues and compost can be used for generating heat and electricity.

Planting trees would fix 2.7 kg of carbon dioxide per square meter,whereas biofeuls with 1% photosynthetic efficiency would produce 0.31 kg of carbon dioxide per square meter when combusted.

Sarrah Putwa

References

Vennestrøm, P. N. R., Osmundsen, C. M., Christensen, C. H. and Taarning, E. (2011), Beyond Petrochemicals: The Renewable Chemicals Industry. Angew. Chem. Int. Ed., 50: 10502–10509. doi:10.1002/anie.201102117

David Mackay. Sustainable Energy – without the hot air http://www.withouthotair.com/c6/page_43.shtml (accessed Feb 28, 2018).

Michel, H. (2012), Editorial: The Nonsense of Biofuels. Angew. Chem. Int. Ed., 51: 2516–2518. doi:10.1002/anie.201200218

 

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Posted on February 28, 2018 by in Chemistry in the news, Issues in Chemistry

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Is Sleep Loss a Problem? Not for These Blind Fish!

Not only do all species vary in ability and behaviour, but fundamental biological needs are subject to variation across the animal kingdom. This evolutionary diversity is  reflected in the difference in amount of sleep necessary for each species (1).  Although the considerable variation in sleep is recognized, little information is known about the evolutionary basis that drives the emergence of such diversity.

A prominent example of sleep variation has recently been studied (2), comparing the Mexican cavefish (3) found in the Sierra del Abra region of Northeast Mexico, to their existing surface ancestors. Multiple Pachón cavefish populations have independently evolved to sleep up to 80% less than the surface dwelling species, with no apparent adverse effects on their function or health.

Comparison of Astyanax mexicanus surface fish and Pachón cavefish

Figure 1: A comparison of Astyanax mexicanus , the blind Mexican cavefish (right) to their relatives that live on the surface (left) Credit: J. B. Jaggard et al./eLife/CC BY 4.0

Figure 1: A comparison of Astyanax mexicanus , the blind Mexican cavefish (right) to their relatives that live on the surface (left) Credit: J. B. Jaggard et al./eLife/CC BY 4.0

The Pachón  cavefish have smaller, if not absent, eyes and lack pigment as shown in Figure 1. The enlarged hypothalamus of the Pachón cavefish has been reported, attributing to many behvioural differences from the surface counterparts. It is thought that ecological differences that affect food availability have driven this evolutionary variation in not only the physical features of these species but also in their sleep behaviour (4).

Investigation into to the regulation and expression of hcrt, a highly conserved peptide known to alter sleep in other species, has offered insight in the sleep variation observed in the Mexican cavefish. Researchers found that although the genetic sequence of this regulatory peptide is identical in the adult Pachón and surface cavefish, there is significant increase in the expression of hcrt in adult Pachón (Figure 2).

Figure 2: HCRT Expression in Pachón (orange) and Surface (blue) Cavefish

Figure2: HCRT Expression in Pachón (orange) and Surface (blue) Cavefish

The adult Pachón cavefish expressed the HCRT peptide four times more than the surface species. With this finding, researchers tested how inhibiting this particular peptide would affect the sleep behaviour of the Pachón species. When HCRT expression was suppressed in the Pachón cavefish, increases in time spent sleeping were observed, confirming the dependence of their sleep behaviour on the HCRT peptide.

-Jojo Nijjar

References:
1. Campbell, S. S.; Tobler, I. Neuroscience & Biobehavioral Reviews . 1984, 8,269–300.
2. Jaggard, J.B.; Stahl, B. A.; Lloyd, E.; Prober, D.A.; Duboue, E.R.; Keene, A.C. Life Sciences Journal. 2018, e32637.
3. Keene, A.; Yoshizawa, M.; McGaugh, S. Biology and Evolution of Mexican Cavefish. San Diego, USA, 2016.
4. Menuet, A.; Alunni, A.; Joly, J.S.; Jeffery, W.R.; Rétaux, S. Development. 2007, 134, 5, 845-55.
5. Siegel, J.M. Nature. 2005, 437, 1264-71.

 

 

 

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Posted on February 26, 2018 by in Chemistry in the news

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Can Cigarette Butts Be the Next Huge Source of Fuel?

Over a billion people all over the world smoke on average six trillion cigarettes every year and their littered cigarette butts pose a large environmental waste and water pollutant problem to the community and wildlife. However, a study done by researchers at the University of Nottingham uncovered that these waste products can be used as a source of hydrogen storage material.

Figure 1: Cigarette Butts                                          Source: Flickr by Alexander C. Kafka

As of November 2017, Materials Chemistry Professor Dr. Mokaya and his undergraduate student Troy Blankenship successfully converted cigarette butts into the starting materials needed for hydrogen storing. Hydrogen can be used as an energy source because of its capacity to generate heat when burned or electricity when reacted with oxygen. This new discovery pushes industries closer in the direction to switch from coal based material to biomass or waste based reusable material for power and fuel.

Cigarette butts contain cigarette filters, a non-biodegradable film base material, called cellulose acetate. These compounds have been a popular subject of waste valorization, a form of converting existing biomass into high performance produce. Cigarette butts produce porous carbons, which have the highest hydrogen storage capability to be currently documented. These findings have a major impact on reducing the litter on public properties and the environmental pollutant of cigarette butts. Toxic heavy metals are found in cigarettes and can wash up into large bodies of water, possibly harming humans and wildlife.

Figure 2: Cellulose Acetate                       Source: Google by Wikimedia Commons

The littered cigarette butts undergo a process of hydrothermal carbonization by adding only water and heat to synthesize a carbon compound called hydrochar. Hydrothermal carbonization imitates the natural process of coal formation in a close container subject to high temperature and intense pressure. Once this product is activated, the compound becomes highly oxygenated, rich in pore volume and increased in surface area. To measure the hydrogen concentration, the compound was weighed before and after the addition of purified hydrogen. Hydrochar can then store hydrogen that can replace gasoline to fuel vehicles and other forms of transportation or natural gas to heat buildings and houses.

Linked Vimeo Video: Biomass Animation by David Curtis

Further research needs to be done in the production of sustainable energy storage materials in the investigation of valorization possibly solving the waste of 800,000 metric tons of cigarette butts produced every year. With oil increasing in value, decreasing in amount and massive increase in carbon dioxide emissions, the need to stray away from fossil fuels is bigger than ever.

-Tiffany Liew

References:

Marksman, D.E., Pirverdyan, A.I., Mokhnachev, I.G., & Perepechkin, L.P. Cellulose acetate fibre for cigarette filters. Fibre Chem. 1971, 3, 292-293.

Mokara, R., & Blankenship, T. Cigarette butt-derived carbons have ultra-high surface area and unprecedented hydrogen storage capacity. Energy Environ. Sci.  2017, 10, 2552-2562.

Tuck, C.O, Perez, E. Horvath, I.T., Sheldon, R.A., & Poliakoff, M. Valorization of Biomass: Deriving More Value from Waste. Science. 2012, 337, 695-699.

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Posted on January 22, 2018 by in Chemistry in the news

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CRUCIAL PLANT NUTRIENT RUNNING OUT : PHOSPHOROUS

Are we at the risk of global starvation? Scientists at the Global Phosphorus Research Initiative predict that in 30-40 years, there won’t be enough mined phosphorus to feed the planet.  

Nations around the world have committed to ensuring food security in alignment with UN Sustainable Development and Millennium Development goals. Exponential population growth, evolution of societal food habits, disproportionate fertilizer usage and absence of phosphorous recycling practices from organic waste has diminished our supply and put us at risk of a global food scarcity. 

Phosphorus Rock Remaining                                  Image Credits: Phosphorus Futures

From the composition of your DNA and bones to plant biomass, this overlooked element is a vital ingredient for survival of organisms. 

Phosphorous based fertilizers sparked the “Green Revolution”, which improved crop yields to feed the 4.2 billion population rise since 1950. The global demand for phosphorus is forecasted to rise by 50-100%. 

Alterations in food habits such as increased preference of dairy and meat-based diets over plant material, has put a strain on phosphorus demands. Studies show that livestock requires double the phosphorus for plant fecundation.

Historically, phosphorus enriched human detritus, decaying plant matter and manure was an  added stimulant for crop yields. Urbanization and innovation of household flush toilets meant human excreta was now disposed in water bodies and waste facilities.

Distribution of World Phosphorous Image credits : Phosphorous Futures

Currently,  the dominant reserves of phosphorous are exclusive to US, China, Morocco, Jordan and South Africa, leaving the mineral trade subject to international and geopolitical influences.

China has levied 135% duty on its phosphorus exports to secure its own domestic supply of the mineral. Morocco is subject to sanctions due to its transgressions of human rights. USA’s primary reserves in California are projected to dry up in approximately 30 years, whereas western European nations and India are utterly devoid of the element, forcing all three regions to heavily rely on imports.

An integrated global effort is imperative to resolve the phosphate scarcity.

Urbanization has birthed population dense cities brimming with phosphorus hotbeds since humans excrete nearly 100% of the phosphorus they consume, yet, only 10% of the waste is recirculated for fecundation. Government initiatives are in motion in European countries and China to extract the mineral from sewage treatment facilities. 

Furthermore, only 50% of phosphorous produced by animal waste and 40% of food residues is agriculturally recirculated. There is increasing movement to minimize phosphorus losses by recycling  plant and animal byproducts for soil nourishment.

Societal changes in food habits, such as ingesting more plant intensive diets and diminishing food wastage, are crucial in avoiding the impending calamity of food insecurity.

Video attributes: https://www.youtube.com/watch?v=Y17HqUsaoj8

References

Elser, J; White, S. Peak Phosphorus, and Why It Matters. Foreign Policy. 2010 

Cordell, D.; Drangert, J.-O.; White, S. Global Environmental Change 2009, 19 (2), 292–305.

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Posted on January 15, 2018 by in Chemistry in the news, Issues in Chemistry, Uncategorized

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