Category Archives: Science in the News

Track Your Stress with Sweat

Posted on March 27, 2019 by | 4 comments

Do you hate having your blood drawn for your lab tests? Could there be a non-invasive way to obtain your lab results?  Perhaps, sweat samples could be used to measure our health status instead.

Sweating is a naturally occurring process, whether it is from exercising or getting nervous on a test. Although sweat can be perceived as wet and smelly, sweat contains various types of biomarkers, such as the stress hormone, cortisol. Since excessive stress can contribute to various health problems, such as high blood pressure, could we use cortisol in our sweats to monitor our stress levels in real-time?

In a recent study, Sekar et al. has developed a wearable electrochemical sensor that can measure cortisol in sweat. The researchers has integrated iron (III) oxide (Fe2O3) in conductive carbon yarn (CCY) to make a semiconductive platform. After that, the platform is coated with antibodies (anti-Cmab) in an electrochemical apparatus, which would make the sensor specific to cortisol. The final product would then become a Fe2O3/CCY immunosensor. The purpose of the study is to see if they can use CCY as a suitable platform for biosensors when monitoring sweats.

Adapted from Figure 1b in the Sekar et al (2019) paper. The black rectangle is the CCY with iron (III) oxide (orange spots). The green cylinder is the electrochemical apparatus. Licensed under a Creative Commons Attribution 4.0 International License

The researchers were able to test the sensor’s detection ability with different concentrations of cortisol. According to Figure 8b below, the line graph shows a linear relationship between the electrical current response from the Fe2O3/CCY immunosensor and the logarithm of cortisol concentration.

Adapted from Figure 8b in the Sekar et al (2019) paper. Each data point with error bar is the result from three successive experiments. Licensed under a Creative Commons Attribution 4.0 International License

The researchers also tested the sensor with real sweat samples from participants after performing cardio exercise. In the bar graph below, the error bars in the pink bar gives the RSD or relative standard deviation of 3.403%, 3.874%, and 4.064% from sweat sample 1, 2, and 3 respectively. These RSDs show small variations in averaged results from three successive experiments when testing with the Fe2O3/CCY immunosensor. According to the paper, the bar graph below shows a correlation between the two methods: the CLIA (chemiluminescence immunoassay) and their Fe2O3/CCY immunosensor. As a results, using CCY may be a possible choice for designing a biosensor that monitors cortisol in sweats.

Adapted from Figure 11 in the Sekar et al (2019) paper. Each pink bar with error bar is the result from three successive experiments. Licensed under a Creative Commons Attribution 4.0 International License

In addition, there are other similar studies that focus on wearable sweat sensors, such that they can transmit data to your phone, and diagnose cystic fibrosis. Therefore, sweat sensors are potential non-invasive diagnostic tools, which may lessen the burden on more invasive blood samples to measure our health status.

References

Stress and Heart Health. https://www.heart.org/en/healthy-living/healthy-lifestyle/stress-management/stress-and-heart-health (accessed Mar 26, 2019).

Sekar, M.; Pandiaraj, M.; Bhansali, S.; Ponpandian, N.; Viswanathan, C. Carbon fiber based electrochemical sensor for sweat cortisol measurement. Scientific Reports 2019, 9, 1-14. https://doi.org/10.1038/s41598-018-37243-w.

Stephanie, Relative Standard Deviation: Definition & Formula. https://www.statisticshowto.datasciencecentral.com/relative-standard-deviation/ (accessed Mar 26, 2019).

Geddes, L. Wearable sweat sensor paves way for real-time analysis of body chemistry. http://www.nature.com/news/wearable-sweat-sensor-paves-way-for-real-time-analysis-of-body-chemistry-1.19254 (accessed Mar 26, 2019).

Dusheck, J. Wearable sweat sensor can diagnose cystic fibrosis, study finds. http://med.stanford.edu/news/all-news/2017/04/wearable-sweat-sensor-can-diagnose-cystic-fibrosis.html (accessed Mar 26, 2019).

 

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Drug Sponge: Absorbing up the problems

Posted on March 27, 2019 by | Leave a comment

https://www.youtube.com/watch?v=fQsYw5brVw8&t=7s

Chemotherapy is a well-known treatment for cancer, using drugs to destroy cancer cells. However, doctors administrate these anticancer drugs with caution because they are also considered poisonous. After cancer treatments, excess drugs can stay in the human body, causing damage to healthy cells, resulting in unwanted toxic side effects. What if there was something that can absorb these drugs like a portable filter?

Various chemotherapy treatments on the growth of mesenchymal stem cells (MSC). MSC is found in bone marrow cells, that contribute to regenerating bone and muscle tissues. Source

Dr. Steven Hetts from the University of California Berkeley initially thought of an idea, to introduce a  sponge-like polymer that can absorb excess chemotherapy drugs. Sponges have immensely grown in popularity in the pharmaceutical field, as the metabolites produced hold biologically active natural products. Approximately 5300 different natural products extracted from sponges have shown pharmaceutical properties, such as anticancer and antibacterial active properties.

Schematic diagram of the developed 3D printed porous absorber. Source

In early 2019, he shared this concept among researchers from other American universities, eventually publishing a paper that describes the development of a porous absorbent polymer. The researchers built the lattice structure using 3D printing that allows the blood to circulate through the bloodstream. In addition, they coated the polymer with a polystyrenesulfonate copolymer, essential for absorbing the chemotherapy drug, doxorubicin.

Doxorubicin: a chemotherapy medication used to treat cancer. Source: Wikimedia Commons

This innovative biomedical device showed great promise, as the polymer efficiently absorbed 64±6% of the drug. Even though this was tested on pigs with healthy livers, the understanding of this device allows researchers to focus on improvements. Lattice size, the type of coating, the thickness of the coating, and the number of absorbers are all possible approaches to a more effective drug sponge.

With this in mind, doctors can potentially administrate higher doses of drugs for more aggressive tumors. In addition, modifications to the drug sponge’s coating can absorb other types of powerful chemotherapy drugs. Although testings on humans are not yet approved by the FDA, the drug sponge is a huge step towards minimizing chemotherapy toxic side effects.

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Painting the town colourful with stretchable cellulose nanocrystals!

Posted on March 24, 2019 by | 1 comment

Just a few months ago, Dr. MacLachlan and his research group from the University of British Columbia discovered some extraordinary new properties of an elastomer made with cellulose nanocrystals (CNCs), which is a biomass-derived substance. These CNCs are everywhere, and can even be obtained by “tak[ing] a piece of paper and treat[ing] [it] with sulfuric acid for 45 minutes,” as Dr. MacLachlan explained. When this abundant and environmentally friendly material was added to the elastomer, it gave the elastomer its optical properties. In other words, when it is stretched under cross-polarizers, the CNC-elastomer changed colour, depending on how much it was stretched!

Stretching the CNC-elastomer under cross-polarizers. Source: Nature Communications

The MacLachlan group started working with CNCs for their optical properties by accident, or as Dr.MacLachlan said, “Serendipity in Science.” When they were looking into cellulose nanocrystals for storing hydrogen, one of the hundreds of samples came out with a red colour, which initiated Dr. Maclachlan’s invested research on cellulose nanocrystals.

Colourful thin films made with cellulose nanocrystals. Source: Chemistry World

The research group was interested in incorporating CNCs into elastomers since previous studies demonstrated that CNC-incorporated materials, such as silica and resins, proved to be inflexible and fragile when stretched. Therefore, the research team decided to investigate different methods that could synthesize a uniform CNC/elastomer structure, which can be stretched and returned to its original form once removing the applied force. The CNCs were successfully incorporated into the elastomer with the help of a sugar additive that helps stabilize the elastomer through evaporation of the solvent. With the success of incorporating elastomer with CNC, this CNC elastomeric material can be further studied for its optical properties.

The MacLachlan group was able to see fascinating optical properties when putting the elastomer under crossed-polarizers. These crossed polarizers permit only one plane of light to hit the elastomer. This is what allows you to see the birefringent optical properties. Birefringence can occur when light enters a material with a very ordered structure. Due to this order, the light is bent into a different plane, while travelling at a variety of speeds. This is the reason why we see the light scattering off from the highly ordered structures in the stretched CNC-elastomer.

Under a high-powered scanning electron microscope, they were able to determine that the cellulose nanocrystals were arranged in a helical shape in the unstretched elastomer, and would start to unwind when the elastomer was stretched. This unwinding elastomer gives rise to unique optical properties.  

When light interacts with the elastomeric material, it gets reflected and bent in different directions, depending on how much the cellulose nanocrystals helical structure unwinds. The extent to which the structure is unwound determines what new colours are visible in the material. In other words, the amount the material is stretched directly related to the colour that we see!

A simple depiction of how the elastomer was made by EISA (evaporation induced self-assembly) and how the cellulose nanocrystals change when stretched in the material. Source: Nature Communications

When the light interacts with the material, it gets reflected and bent in different directions, depending on how much the cellulose nanocrystals helical structure unwinds. The different degrees of unwound structure results in a new colour that we can see in the material. This means that the amount the material is stretched is directly related to the colour that we see!

The observed spectrum of colour we see in inversed when the analyzer is parallel with the polarizers. We see the complementary colours. Source: Nature Communications

The discovery of the optical properties in CNC-elastomer is a significant step in the right direction, which can later be used in many applications. The MacLachlan group is currently making a CNC-elastomer that does not require crossed polarizers so we would be able to see the colour change with our naked eye! This new optical property would open up new possibilities for how this material can be used in our daily lives.

Some future applications include applying a thin layer of CNC-elastomer onto bridge supports and buildings. This would be a major benefit for the residents in Vancouver, as we are in a high-risk earthquake zone. As a result, the thin film could help us determine if our buildings are structurally intact with a simple colour change.

Vancouver’s Lions Gate Bridge. Source: Flickr

Another high impact example would be to coat the shipping boxes with this CNC-elastomer. Ideally, any tampering or damage done to the shipping boxes would be indicated by a colour change in the CNC-elastomer. So say good-bye to damaged Amazon deliveries and hello to a whole new world of satisfied internet customers.

Source: Flickr

This CNC-elastomer and future generations of it will result in endless applications, ranging from sensors in smartphones to incorporating it into helmets for impact sensing – it can do it all! In the 21st century, we live in a very visual society and respond strongly to visual changes like a colour. The impact of a material can have on your life by telling you a lot of information in an eye-catching way, which can bring home the important messages that it may be telling you.  Imagine a future world where a simple colour change contains so many information like we see in a sci-fi movie. It is somewhere we want to live, and we believe that CNCs-elastomer’s have the potential to bring us there!

~ Alan, Amanda, Emily and Isabelle

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Is Westernized Food Killing Our Gut?

Posted on March 24, 2019 by | 1 comment

Well not really killing your gut, but the vast and diverse biome of microbes that live in your gut. That’s right, you have around one hundred TRILLION helpful bacteria living inside of you! They have many jobs, ranging from helping break down food, helping with the production of vitamins, are a key component in our immune system and much more.

Studies have shown that when humans migrate from less westernized cultures to North America, their gut’s microbiome was significantly reduced in diversity and was predominated by two bacteria, Bacteroides and Prevotella. This decrease in diversity is shown to increase the inflammation in your gut, leading to gut-related diseases that are skyrocketing in modern society. Some of these are obesity, diabetes, Crohn’s disease, ulcerative colitis, allergies, and asthma, to name a few. This change in our microbiome was shown to be due to the Westernized high protein/fat/sugar diet whereas more developing countries have diets of very high fibre with fewer meats and fats.

source: Phys.org

Dr. Dan Knights, an assistant professor at the University of Minnesota, has done research on this change of microbiomes using wild monkeys and their captive counterparts to see if there were any differences. He found that the monkeys had much higher microbe diversity in the wild than when they were confined in a zoo.

Shows that the diversity of the primates microbiome decreases significantly when removed from the wild. Error bars indicate SD, and asterisks denote significance at **P<0.01, and ***P<0.001. Source: PNAS

Another exciting result he found was that two different wild monkey species with very different gut microbiomes converged to similar lower diverse microbiomes when captive, even though they did not live in the same zoo, never mind the same continent. They were converging towards the microbiome that modern humans have today.

As primates move from wild to captive, their microbiomes converge in the direction of modern humans. Non-western humans also have higher gut microbiome diversity than humans living in westernized areas. Source: TED

The data also showed that non-western humans followed this trend of having higher microbe diversity and subsequently losing this diversity when moving to the USA. This results in these migrants increasing their risk of obesity, diabetes and other gut-related diseases. These results beg the questions on what this ultimately means for our health? Further, this really makes you wonder, are captive monkeys becoming more like modern-day humans or are we just an example of super-captive primates??

~ Amanda Fogh

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Gravitational constant G, the one value that behind “everything”

Posted on March 22, 2019 by | 1 comment

New equipment for the measuring the gravitational constant G is reported by Li on Nature using two techniques TOS and AFF.

As we all have studied in High school science class or physics class, the reason that an apple will fall from trees, a rocket needs to thrust hot air to the ground to take off and even how can astronauts can ‘fly’ in the middle of air all have to do with gravitational constant G.  The gravitational acceleration is often been mistaken as gravitational constant just as mistaking gravity as the only gravitational force. The gravitational force is the attractive force between any two objects and the force is proportional to the weights of the two objects(assume the distance is a constant) and this proportion is the G. Just like the most common noticed gravitational force we are experiencing, gravity, is actually the attraction between us or an object with earth.

Nowadays, even though there are still some strong arguments on G should not be treated as a constant, it is generally been accepted that Newton’s law of universal gravitation is ‘true’ and gravitational constant can be measured.  Starting from this point of view, getting an accurate gravitational value is crucial since this value has been used for lots of daily life technology and precise aerospace calculations in astronomy.

Uncertainties of current and previous experiments. Made by Stephan Schlamminger

This passage will compare the traditional way of measuring G and a new improved way of doing it developed by a research group lead by Qing Li. The measurement of G is affected by lots of factors such as air, magnetic field and more importantly other objects that are near the equipment. For the reason of presenting so much factors, the uncertainty of the results is very large as reported by Mohr the uncertainty is 47 parts per million. While in Li’s group, they achieved recorded the smallest uncertainty of 14 parts per million while the largest uncertainty is 550 parts per million larger.

In the early days, the first successful measurement of G was done by Cavendish in 1798 and the part that is hanged by string is two connected spheres in a dumb-bell shape as you can see from the video below.

But in Li’s group, they built a “two plate-containing torsion balances” which uses two plates to replace the spheres to improve the precision. Also what worth mention is they used a fused silicon dioxide (silica) fibers with high-quality factor of the torsional oscillation mode (Q) to reduce the anelastic effect. And with all the other improvements together they managed to obtain the smallest uncertainty.

The instruments made by Li’s team. Source

This experiment can potentially benefit a lot of area of work by providing a more accurate fundamental constant value. The accuracy of work and research from the benefited field can also be improved.

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The Return of Measles

Posted on March 22, 2019 by | 2 comments

Why Parents Fear Vaccines | Tara Haelle https://www.youtube.com/watch?v=ggtkzkoI3eM (Accessed Mar 20, 2019)

Can vaccines cause autism? A question posed by many uneducated masses, the fear of an article read online far outweighing the scientific backings of hundreds of research studies1. For the majority of people, the answer is simple, vaccines are completely safe, but it only takes a small group of people to make a huge negative impact on the rest of society. By being entrenched in the mindset that vaccines are harmful, it creates a backdoor for the re-introduction of various harmful and deadly diseases, like measles2.

                              Infographic of measles cases in the United States                                Blount, E. Misinformation on Vaccines Causes Measles Outbreak. https://gmhslancerledger.com/5508/news/misinformation-on-vaccines-causes-measles-outbreak/ (accessed Mar 21, 2019).

Measles is a highly contagious and highly preventable disease. Symptoms can lead to high fevers and body-wide rashes. Complications with the diseases can arise including pneumonia. They are also responsible for infecting 20 million people each year and resulted in the deaths of hundreds of thousands3. The disease is airborne so passing it on person to person is quite easy. Once a person is infected there is no specific treatment, only supportive care. Measles is most common in developing parts of the world such as developing parts of Asia, but with the return of “anti-vaxxers” it is making its comeback to many developed parts of North America. As shown in the provided figure, the number of measles deaths was expected to rise after continually falling.

A figure of estimated worldwide deaths of measles and projected worst-case scenarios
Global Measles Mortality, 2000–2008. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5847a2.htm (accessed Mar 21, 2019).

Herd immunity is a form of indirect protection in which a large portion of a population is immune to disease through previous exposure or vaccines, thereby providing a measure of protection for those that are not immune4. It works by having a large portion be immune, therefore containing a breakout from spreading person-to-person. This is one of the best forms of protection for those that can not be immune due to medical reasons. This system falls apart though if more and more people decide against vaccinations. The fewer people that are immune, means the more opportunity for the outbreak of diseases to spread and infect those who are not immune5.

                                                 An infographic of herd immunity                                      Herd immunity. https://en.wikipedia.org/wiki/Herd_immunity (accessed Mar 22, 2019).

Imagine a world where polio is still a prevalent disease affecting millions or a world where smallpox is still around and active. The eradication of these diseases was only possible due to the worldwide vaccine movement and subsequent herd immunity that followed6. Most adults are set in their stubborn ways, as such explaining to them the importance of vaccines usually falls on deaf ears. The best solution to prevent further outbreaks and help create a world eradicated of preventable diseases is to start young and teach kids the importance for future generations.

1Dixon, G. N.; Clarke, C. E. Science Communication 2012, 35 (3), 358–382.

2Chang, L. V. Health Economics 2018, 27 (7), 1043–1062.

3Moss, W. J. The Lancet 2017, 390 (10111), 2490–2502.

4Fine, P.; Eames, K.; Heymann, D. L. Clinical Infectious Diseases 2011, 52 (7), 911–916.
5Betsch, C.; Böhm, R.; Korn, L. Health Psychology 2013, 32 (9), 978–985.

6Phadke, V. K.; Bednarczyk, R. A.; Salmon, D. A.; Omer, S. B. Jama 2016, 315 (11), 1149.

~ Danial Yazdan

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Blood test: the future diagnostic method for Alzheimer’s Disease

Posted on March 22, 2019 by | Leave a comment

Alzheimer’s disease (AD) is a type of brain disease that causes problems with thinking, memory, and behavior and leads to dementia. AD is frustratingly common among seniors over the age of 65. Approximately there are 5.8 million people in the United States are suffering; by 2050, this number will probably increase to 14 million.

How Alzheimer’s Changes the Brain. Source: https://www.youtube.com/watch?v=0GXv3mHs9AU

Although there is no current cure, an early and accurate diagnosis can help patients to access proper treatments which can slow the worsening of symptoms and improve quality of life for those suffering from AD. However, no single and efficient test can provide a reliable diagnosis. After doctors conduct interviews with patients with possible signs of symptoms, several blood tests and brain imaging are needed to rule out the other brain illnesses and confirm the diagnosis. This process may take several months, and the accuracy is only up to 75 to 85%. Researchers have been working on better and more efficient diagnostic methods. One advanced tool is Positron emission tomography (PET) scans which can detect the hallmark of abnormal protein clusters in brains and afford reliable results. However, these tests can cost thousands of dollars, and most people do not have access and never get tested.

PET scan showing glucose metabolism associated with decreased cognitive function.
Source: https://www.sciencedaily.com/releases/2009/07/090714085812.htm

For decades, researchers have been on the quest to develop a blood test for AD for blood testing is the most common and affordable medical diagnostics. The exciting news is that researchers have identified blood-based biomarkers of the disease that can provide fast and accurate measurements. A biomarker is a substance whose detection indicates a particular disease; in the case of AD, the particular substance is a protein called amyloids. One significant pathological signature of AD is the appearance of clumps of abnormal amyloid protein in brains. Those clumps are made of a mixture of peptides which form from the breakdown of the amyloid precursor protein (APP). In 2010, Bateman and his colleagues from Washington University School of Medicine found that the amount of a peptide known as amyloid-b 42 (Ab42) is significantly higher in the in a patient’s blood sample. However, several follow-up studies have suggested that the number of amyloid peptides, including Ab42, increases as people grow old, so the method of detecting Ab42 is proved unhelpful. In recent years, some research shows that the ratio of Ab42 to another peptide Ab40 indicates the significant difference in the diseased brain from a cognitively normal brain. Written in Nature last year, Yanagisawa and his team from the National Center for Geriatrics and Gerontology reported that using the ratio of these two peptides as the biomarker provides highly accurate results.

Figure 1: The clearance rate of amyloid- 40 and 42 peptides of 12 Alzheimer’s disease participants (red triangles) and 12 control (blue circles). The average clearance rate of amyloid-40 and 42 peptides is slower for AD individuals compared with cognitively normal control groups, suggesting the potential usage of these two peptides as biomarkers. Source: https://www.nature.com/articles/nature25456.

Although blood tests are not approved for commercially used yet, most researchers in the field believe that an affordable and accurate blood test for everyone will be commercially available in five years, especially when more proteins, such as neurofilament light polypeptide, are also found to be good candidates for biomarkers.

References:

National Institute on Aging. What Is Alzheimer’s Disease? https://www.nia.nih.gov/health/what-alzheimers-disease (accessed on March 21, 2019)

Alzheimer’s Association. Facts and Figures. https://www.alz.org/alzheimers-dementia/facts-figures

RadiologyInfo.org. Positron Emission Tomography-Computed Tomography. https://www.radiologyinfo.org/en/info.cfm?pg=pet (accessed on March 21, 2019)

Strimubu, K.; Tavel, J. A., Curr. Opin. HIV AIDS., 2010, 5, 463-466

O’Brien., R. J.; Wong, P. C., Annu. Rev. Neurosci. 2011, 34, 185-204

Amyloid precursor protein, Wikipedia.org, https://en.wikipedia.org/wiki/Amyloid_precursor_protein (accessed on March 21, 2019)

Mawuenyega, K. G.; Sigurdson, W.; Ovod, V.; Munsell, L.; Kasten, T.; Morris, J. C.; Yarasheski, K. E.; Bateman, R. J., Science, 2010, 330, 1774

Arnaud, C. H., Study tests plasma biomarkers for Alzheimer’s. https://cen.acs.org/articles/96/i6/Study-tests-plasma-biomarkers-Alzheimers.html (accessed on March 21, 2019)

Nakamura, A.; Kaneko, N.; Villemagne, V.L., Kato, T.; Doecke, J.; Dore, V.; Fowler, C.; Li, Q.; Martins, R.; Rowe, C.; Tomita, T.; Matsuzaki, K.; Ishii, K.; Ishii, K.; Arahata, Y.; Iwamoto, S.; Ito, K.; Tanaka, K.; Masters, C. L.; Yanagisawa, K., Nature, 2018, 554, 249-254

Lewczuk, P.; Ermann, N.; Andreasson, U.; Schultheis, C.; Podhorna, J.; Spitzer, P.; Maler, J. M.; Kornhuber, J.; Blennow, K.; Zetterberg, H., Alzheimer’s Research & Therapy. 2018, 10

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Is it actually 100% oregano?

Posted on March 9, 2019 by | 6 comments

Have you ever wondered what is in the food you eat? This pizza may contain additional ingredients that you may not be aware of.

According to Canadian Food Inspection Agency (CFIA), food fraud is an emerging global issue. In fact, food fraud “may cost the global food industry $10 to $15 billion per year”. Examples of food fraud may include substitution/addition of ingredients or tampering/mislabeling of food packages, and selling these inferior products at a higher price for profit. Food fraud is problematic; therefore, it is crucial that CFIA and the food industry combat food fraud to protect consumer safety.

However, in 2016, there has been a report of adulterated dried oregano in Australia. Some brands that declare “100% oregano” only have 33% – 50% of actual oregano. The remaining percentage could contain additional olive and myrtle leaves as fillers. The presence of olive and myrtle leaves can pose a health risk, because it can carry a higher amount of pesticides, which can contaminate the dried oregano. Therefore, it is important to find a way to detect these fillers, so that they can be eliminated from the market.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Recently, a paper from the journal of Food Chemistry published in 2019, suggests that GC-MS (a common instrument in a Chemistry lab) can be used to detect and measure the amount of pesticides in adulterated oregano samples. By identifying the most predominant pesticides in adulterated oregano, the pesticides can be used as potential markers for identifying adulterated oregano.

But how does GC-MS work? In the “GC” part of the instrument, the pesticides travel through the column, in different speeds, based on its unique chemical properties. Once all of the pesticides are separated, they go through the “MS” part of the instrument, where they get fragmented by a beam of electrons before it travels through the mass analyzer and reaches to the detector for data collecting (see image below).

A schematic of the GS-MS instrument. Detector is attached to the right side of the mass analyzer (not shown). Cwszot, Kkmurray, Creative Commons  Attribution 2.5 Generic (CC BY 2.5), Electron ionization GC-MS.png

As a result, pesticides (cyfluthrin (sum), cyhalothrin lambda, and pyriproxfen) are present in higher quantity in the 34 adulterated oregano samples than in the 42 genuine samples. Therefore, cyfluthrin, cyhalothrin lambda, and pyriproxfen could be used as potential markers for detecting adulterated oregano.

Graph from the research paper. Click on the image for high-definition. Drabova et al., Creative Commons Attribution 4.0 International (CC BY 4.0),  Adapted from Figure 5 in Food fraud in oregano: Pesticide residues as adulteration markers

In conclusion, it is possible to identify the adulterated samples by using a chemical technique to stop food fraud. Although CFIA and food industries work to protect consumers from food fraud, CFIA suggests a few ways for consumers to identify food fraud.

But as for me, I will stick to growing my own oregano in my backyard.

Updated: March 28, 2019 

Reference:

Canadian Food Inspection Agency. The CFIA Chronicle. http://www.inspection.gc.ca/about-the-cfia/the-cfia-chronicle-fall-2017/food-fraud/eng/1508953954414/1508953954796 (accessed Mar 08, 2019).

Canadian Food Inspection Agency. Food fraud. http://www.inspection.gc.ca/food/information-for-consumers/food-safety-system/food-fraud/eng/1548444446366/1548444516192 (accessed Mar 08, 2019).

Canadian Food Inspection Agency. Types of food fraud. http://www.inspection.gc.ca/food/information-for-consumers/food-safety-system/food-fraud/types-of-food-fraud/eng/1548444652094/1548444676109 (accessed Mar 08, 2019).

The Sydney Morning Herald. Food Fraud: Popular oregano brands selling adulterated products. https://www.smh.com.au/business/consumer-affairs/food-fraud-popular-oregano-brands-selling-adulterated-products-20160405-gnygjo.html (accessed Mar 08, 2019).

Drabova, L., Alvarez-Rivera, G., Suchanova, M., Schusterova, D., Pulkrabova, J., Tomaniova, M., . . . Hajslova, J. Food fraud in oregano: Pesticide residues as adulteration markers. Food Chemistry. [Online] 2019, 276, 726-734. doi:10.1016/j.foodchem.2018.09.143 (accessed Mar 08, 2019).

Canadian Food Inspection Agency. How food fraud impacts consumers. http://www.inspection.gc.ca/food/information-for-consumers/food-safety-system/food-fraud/how-food-fraud-impacts-consumers/eng/1548444986322/1548445033398  

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Forensic: How to Measure the Unknown Time of Death from Only Bone and Hair Remains

Typically, TV forensic shows, such as CSI and Bones, portray how forensic cases are fast and easy to solve within a couple of episodes. However, that is not true. Unlike in forensic shows, forensic cases take a long time to solve in real life, due to challenges that investigators have to face.

One of the challenges that criminal investigators have to solve is to determine the post-mortem interval (PMI) from decomposed skeletons. Post-mortem interval is the time after someone has died, which is important when the cause of death is unknown. Usually, medical assessment of corpses can determine the PMI after the body is dead for the first few days. However, when the victim’s bones and hairs are found after a few years, the accuracy of the PMI lowers. Therefore, new method is required to provide a more accurate estimation of the extended time of death.

Currently, there are numerous studies that use different methods for solving the PMI. Many methods include analyzing soil chemistry and insects at the crime scene. Since these methods could be complementary to each other, the scientists in Switzerland believe that combining these methods would improve the long-term PMI estimate, while illustrating how the crime scene could have occurred. Therefore, the Swiss scientists have attempted to use five different approaches simultaneously to estimate the PMI of the bone and hair remains. Once the soil, bone, and hair samples are collected from the Swiss forest, the scientists use five different approaches for analyses, which include using radiocarbon dating, analyzing pH and soil chemistry, counting and classifying nematodes and mites, and sequencing DNA of soil micro-eukaryotes.

 

After analyzing the findings, the scientists are able to propose a possible PMI, as well as the crime scene. First of all, the radiocarbon dating determines that the bones belong to a young adult male. Secondly, chemical, nematodes, and micro-eukaryotic analyses suggest that the remains have been partly decomposed in the forest for at least 8-9 months. Finally, the evidence from mites suggests that the corpse is partly decomposed in a separate confined place, because these mite species are only found in confined environment. Therefore, the suspect(s) could have allowed the corpse to decompose in a confined area before relocating it to the Swiss forest. As a result, the PMI of the dead victim appears to be at least 8-12 months before the body is discovered.

The skeleton that is found in a Swiss forest. Ildikó Szelecz, Sandra Lösch, Christophe V. W. Seppey, Enrique Lara, David Singer, Franziska Sorge1, Joelle Tschui, M. Alejandra Perotti & Edward A. D. Mitchell, Source, Creative Commons Attribution 4.0 International Licence

Overall, the study shows that using five approaches simultaneously in a forensic case study can estimate the PMI, while illustrating a possible crime scene of how the victim could have died. Moreover, all of the approaches can be complementary with each other, in order to provide more evidence from scarce remains. In conclusion, it is possible to further develop this technique in order to estimate PMI in other forensic cases.

Update: Blog post has been revised on 2019, Feb 15th.

Reference

Rasmussen College. How Accurate are Crime Shows on TV? Debunking 7 Common Myths. https://www.rasmussen.edu/degrees/justice-studies/blog/crime-show-myths-debunked-forensic-experts-tell-what-life-is-real/

Keele University. Chemical Ecology. PMI in Forensic Entomology. https://www.keele.ac.uk/chemicalecology/projects/pmi/

American Council on Science and Health. How Chemistry, Microbiology Could Help Catch A Killer. https://www.acsh.org/news/2018/01/18/how-chemistry-microbiology-could-help-catch-killer-12422 .

Szelecz, I.; Lösch, S.; Seppey, C. V. W.; Lara, E.; Singer, D.; Sorge, F.; . . . Mitchell, E. A. D. . Comparative analysis of bones, mites, soil chemistry, nematodes and soil micro-eukaryotes from a suspected homicide to estimate the post-mortem interval. Scientific Reports. [Online] 2018, 8(1), 25. doi:10.1038/s41598-017-18179-z.

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Posted on January 29, 2019 by in Biological Sciences, Science in the News, Uncategorized

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