the catalyst: november 2015 issue

CatalystNovember 2016 1

November 2015 | novembre 2015Volume 6: Issue 2

Student Science Journal - Journal étudiant scientifique

PAGE 18Announcing the winners of the fAll illustrAtion contestPAGE 6

stop seeing gmo As omgPAGE 19

CatalystNovember 20162

THE TEAM | L’ÉQUIPE

Editor-in-Chief Vanessa NzeribePoduction Manager Christine WangRédacteur-en-chef Setti BelhouariDeputy Editor-in-Chief Yen TranAssistant Production Manager Ashley TennWebsite Manager Michael LeungVP Media Ashley ChenVP Promotions Ashley TennIllustrations Manager Mariko Sumi

Authors | AuteursKevin AmélétéVeronika CencenWinston CheungAngela DouAlanna LealeJohanne MathieuElizabeth RichardsonHadjar SaidiAlexander SatensteinCassidy SwanstonAshley TennYen TranTanya Yeuchyk

Editors | EditeursNicole AuclairEmily HuangNatasha KasulisAlanna LealeOlivia MagwoodTatsiana Yeuchyk

IllustrationsSanmeet ChahalJohn EvansAlanna LealeAshley Tenn

Translators | TraducteursSanmeet ChahalLaura GoodwinLaila FazalMihaela Tudorache

Featured | Sélectionné(e)sDawn BlairLina LiuNooria RizviSaania Tariq

November Contents | Contenu de novembre

Illustration Contest ResultsPAGE 6

Stop Seeing GMO as OMGPAGE 6

Food Science: Yummy yogurtPAGE 7

Ta b l e o f C o n t e n t s


Ta b l e o f C o n t e n t s


Why is yogurt healthier than milk?

A) Yogurt has higher nutritional content than milk. B) Yogurt has denatured proteins which are easier to

digest. C) Yogurt contains probiotic bacteria. D) All of the above.

See answers online.

FOOD SCIENCE: YUMMY YOGURT

Historically, yogurt makers have fermented milk spontaneously, yielding tremendous variation across the globe. Yogurt today is made from milk and bacteria, fermenting under specific, controlled conditions. In the name of scientific curiosity and knowledge, we have secured a tour to investigate the making of yummy yogurt in a hypothetical, yogurt manufacturing facility.

Let us begin our yogurt factory tour.

The

Yogurt Factory Milk Modification:

Yogurt processing begins with milk composition. In the first chamber, you can see our industrial mixers pumping fats, milk solids, and other nutrients into the milk mixture. This influences the texture and nutrition of yogurt.

For creamier yogurt, higher fat content is desired, but for thicker yogurt, non-fatty solids like proteins are added. Typically for our commercial yogurts, we reduce fat, increase lactose to 30-35%, and spike proteins, minerals, and vitamins. Because sugars are to be fermented by our yogurt bacteria later, sugars and other sweeteners are not added at this stage.

Once our milk modification is completed, the mix is sent to the pasteurization chambers next door.

Pasteurization:

Next, we have our yogurt pasteurized by the plate heat exchangers, at 95°C for 8-10 min. According to food scientists, Chandan and O’Rell, pasteurization allows for the destruction of competitive microorganisms in order to create an optimal condition for yogurt culture growth. Also, the denaturation of milk proteins refines yogurt texture.

At high heat, lactoglobulin in milk denatures to form cross-links and gel, reducing unwanted bacteria and retains water in the yogurt mix. By enhancing the water absorption capacity up to 95%, the yogurt

base improves in viscosity, smoother consistency, and stability.

Homogenization:

Following pasteurization, the yogurt base is then homogenized for further refinement of its consistency. At temperatures of 55-85°C, fat globules are beaten down by 10-20 MPa of pressure to ensure uniform fat distribution in the yogurt. An interest fact to note is that heat treatment and homogenization of yogurt are important to digestibility in the stomach, by forming soft coagulum.

Fermentation:

Upon cooling the homogenized yogurt base to growth temperatures (41-43°C), starter yogurt cultures are added for fermentation. The inclusion of two main bacteria, Streptococcus salivarius subspecies thermophilus (ST) and Lactobacillus delbrueckii subspecies bulgaricus (LB), in the yogurt starter is essential to the characteristic texture, taste and aroma of yogurt.

The temperature is held at 41-43°C for starter bacterial growth in the yogurt base. ST converts lactose into lactic acid by fermenting glucose. Technically, all other monosaccharides can be fermented after ST isomerizes them into glucose. The volatile by-products of fermentation, such as acetaldehyde, diacetyl, and acetic acid, characterize a complex, pleasant yogurt aroma. Meanwhile, the accumulation of lactic acid contributes to the acidic, refreshing taste of yogurt. Lactic acid also acts as a preservative against unwanted microorganisms, but does not hinder LB from enhancing the yogurt.

4th year BCH

4th year BIM

keep reading Z

F o o d S c i e n c e

Illustrated by Alanna Leale, M.Sc. candidate in BIO


As lactic acid is produced, the pH drops to create an acidic environment for LB to thrive. LB can hydrolyze casein into smaller peptides, and with the help of ST’s active peptidase, the resulting peptides are converted into free amino acids.

For additional flavour and nutritional benefits, optional bacteria, such as Lactobacilus acidophilus and genus Bifidobacterium, can be added. Examples of probiotic effects, as identified by Takano and Yamamoto, include the enhancement of protein digestibility, mineral absorption, and immunity.

Cooling:

Once the desired viscosity, aroma and plain yogurt taste is attained, the yogurt is placed into the 4°C fridge for cooling. The cooling stops fermentation and culture growth.

Flavouring:

Pure yogurt can taste very sour due to the accumulation of lactic acid during the fermentation stage. To appropriate taste for consumers, yogurt can be flavoured and sweetened. Some of our factory’s most popular flavours include fruits such as strawberry and honey. Depending on the type of yogurt, the fruits can be added at the bottom of the cup (set style yogurt) or blended into the fermented yogurt mix (Swiss style yogurt).

After our yogurt is fully processed and flavoured, it is time to move onto the packaging facility.

Packaging:

From the fermentation vat, the yogurt is pumped into the packaging containers. As mentioned, soft-served yogurt is packaged into two styles: set style yogurt and Swiss style yogurt. Alternatively, we have hard pack frozen yogurt which has been textured at 0-4°C, agitated, and crystallized for frozen storage.

We have reached the end of our tour of the production of yogurt. Available in the next room are free samples and activities. Please be welcomed to make Greek yogurt or yogurt-dipped pretzels with us!

Your Own

Yogurt-covered Pretzels

1. Preheat the oven to 120°C (250°F).

2. Mix 5 cups of confectionary sugar with 2 cups of low fat yogurt, one cup at a time.

3. Dip the pretzels, one at a time, until they are thoroughly covered in yogurt.

4. After coating all the pretzels in yogurt, place them on a wire cooling rack, with a baking sheet beneath, and into the oven, turned off.

5. Wait 3-4h for the coating to harden.

6. Remove the pretzels from the oven, and store them in an airtight container.

Adapted from Stonyfield’s recipe.

What is Greek yogurt?

Greek yogurt is a type of strained yogurt, where we filter out water and sugars.

How is Greek yogurt content different?

The yogurt thickens as the protein ratio rises. Although vitamins are filtered out with the fats, nutrients can be re-added after filtration.

F o o d S c i e n c e


The Catalyst’s First Annual Fall Illustration Contest

First Place:Christine Wong,

2nd year BPS

First Place $100 gift certificate to DeSerres

Runner up $50 gift certificate to DeSerres

Runner up:Lina Liu,

1st year BIM

F a l l I l l u s r a t i o n C o n t e s t


The Catalyst’s First Annual Fall Illustration Contest

First Place: Winston Cheung, 4th year BIM

Runner up: Kevin Li, 4th year BCH

Email [email protected] for more instructions to receive your prize!

F a l l I l l u s t r a t o n C o n t e s t


JUDGES’ C H O I C E

Saania Tariq, 2nd year BIM

Dawn Blair, 3rd year BIM


Check out our website https://uocatalyst.wordpress.com/ for articles translated in French

Runner up: Lina Liu, 1st year BIM

Nooria Rizvi,3rd year BCH


T i m i n g i s E v e r y t h i n g

Timing is Everything: Finding an adaptive basis for synchronized malarial infections

, M.Sc. candidate in BIO

keep reading Z

Alanna Leale, M.Sc. candidate in BIO


keep reading Z



→ That these were not all named after the same man?

Bernoulli differential equation

Bernoulli distribution

Bernoulli number

Bernoulli polynomials

Bernoulli process

Bernoulli Society for Mathe-matical Statistics and Proba-bility

Bernoulli trial

Bernoulli's principle

The Bernoulli family contributed to mathe-matics and science to-gether spanning from 1654 to 1789. Imagining having that family reputation!



Handling human heart samples and extracting their cells is a science student’s fantasy, but this was my reality this summer working at the University of

Ottawa Heart Institute. As a recipient of the Undergradu-ate Research Scholarship, I was given the opportunity to spend two summers working in a lab of my choice. I was lucky enough to find a position in the lab of Dr. Darryl Da-vis, where I discovered a whole new world of scientific re-search.

Before being allowed to work with more valuable hu-man-derived cells, I had first started out practicing cell culture processes using inexpensive and rapidly-growing cells. Once I learned the concepts, I was able to assist with more finite procedures, including the extraction of cardiac stem cells. We would receive a fresh biopsy of a human heart, mince it into tiny pieces, and then incubate them in cardiac explant medium until the individual cells migrated out onto the plate. The cells were then harvested and fro-zen in freezing media for future use.

Why did we investigate cardiac stem cells? Great prog-ress within the last decade has been made towards a new treatment for heart failure using these cells. It was previ-ously thought that the heart, like the brain, was a post-mi-totic organ - meaning its cells lack the capacity to regener-ate. However, a study in 2003 proved otherwise. It followed that a small number of cardiac stem cells exist were able to differentiate into mature cardiomyocytes in the event of minor cell death or damage. An estimated total of 50% of cardiomyocytes are renewed over the human lifetime, but the regenerating capacity decreases with age. Heart failure is a condition where damage to the heart muscle renders it unable to provide sufficient circulation of blood and nutri-ents. After a heart attack for example, a patient is left with scar tissue on the heart, consequently impairing its efficien-cy. A patient with heart failure has typically lost over one

billion cardiomyocytes, and so native stem cells are not nu-merous enough to be able to significantly repair the tissue.

A novel treatment for heart failure involves the admin-istration of cardiac stem cells at the site of the damage. The goal of this approach is to increase the number of ac-tive cells, and therefore improve heart function. Clinical tri-als have shown that this method is safe and results in the improvement of contractile function in the heart. Despite promising results, a major issue remains in the difficult retention of injected stem cells. More than 90% of inject-ed cells are lost from the target area due to leakage into the lymphatic or circulation systems. Additionally, many of those that do remain die within weeks from low nutrient content. One method of improving engraftment is encap-sulation, which is something I also had the opportunity to work over the summer. We used biocompatible proteins to make microscopic capsules that mimic the natural domain of cells in the body. This process aids in cell survival by providing a stabilizing, three-dimensional environment to live and grow in. Early work from the Davis lab shows that encapsulation can improve cell retention, which brings im-portant future clinical applications. Stem cell therapies are not yet approved for clinical use, but continuing trials and growing data are bringing researchers closer to this goal.

When working with cell culture, you need to use all ster-ile materials extremely carefully and meticulously, to avoid the slightest contamination. It was an eye-opening experi-ence to see the sheer amount of work which researchers put in each day, spanning many years, to make the discov-eries we read about later in the news. I look forward to next summer to keep learning and make any contribution I can towards this life-saving technology!

Special thanks to Dr. Darryl Davis, M.D, Pushpinder Kanda, Audrey Mayfield, and Bin Ye.

Working Hard, Heart-ly WorkingWritten by Tatsiana Yeuchyk, 1st year BIM


By: Sanmeet Chahal, 4th year PHY

By: John Evans, 3rd year PHY (top left, top right, bottom right)

Email [email protected] for a chance to have your own comics published!

C o m i c C o r n e r


Behind the day-to-day monotony of lec-tures and studying

at the University of Otta-wa, there exists a world of research that runs with the help of both graduate and undergraduate students. For these students, it is a sprawling other life filled with hard work, long days, and professors working closely to guide them along the way. While this is not just the reality within our Faculty of Science, it is here that we see work done in countless fields which could further benefit humanity. Still, this research of-ten goes unnoticed by the rest of our student popu-lation. Even after publication, it is rare that students will see that their peers have contributed to certain papers, let alone know these papers existed. Con-necting Young Minds (CYM) is a conference aimed to remedy this low awareness.

The Catalyst was invited to the event, and as I found myself a seat among the audience, I grew cu-rious to see what sort of research was being done by other undergraduate students. Would the level be as advanced as those done by Master’s and PhD stu-dents? What fields would be showcased? What year were these students in? I leafed through the program, eagerly waiting for the conference to start.

CYM was a bilingual undergraduate research con-ference that held its first event on August 28th, 2015. The opening remarks were delivered by co-presidents Aida Ahrari and Anabel Bergeron, filled with referenc-es to the human connectome – the neurological paths that one’s neurons take in order to process thought. It was here, they said, that our brains were able to take in and process new information, where each addition would add itself to the connectome. Activi-ties that enhance the connectome included studying

and, of course, research. The goal was to open ourselves up to the idea of enriching our minds with the opportunities pre-sented by research at our school.

This sentiment was shared by the professors who carried on the open-ing remarks, speaking about their experiences and benefits in undergrad-uate research. I found my-

self keen to listen to their stories of their success and further intrigued by what they were able to accom-plish at such a young age. But these were current professors, tenured and well-respected. How did the current undergraduates compare?

The answer to my question came soon enough, once the presentations started. Presentations were 15 min each, with accompanying slideshows and varying levels of complexity. Subjects ranged from possible treatments of acute myeloid leukemia to the importance of citizen science in ecological research. Most impressively, each student knew their research by heart with passion. Elevator pitches of 5 min were also presented at CYM, each competing for a cash prize at the end, as determined by the judges.

The talks were clear and concise, overall impres-sive, and reminded me that important research is nev-er limited to just Master’s or PhD students. It is possi-ble to get involved without a degree; opportunities just need to be sought out. Connecting Young Minds was put together exactly for this purpose – to bring togeth-er and present the research done by our peers in the Faculty of Science, to show that research does not have to be a long, distant dream, years away from be-ing fulfilled. Research is being done right now through hard work and dedication by other undergraduates having the passion for what they love.

Showcasing Undergraduate Research with CYMWritten by Ashley Tenn, 2nd year BCH

Photos taken from the CYM conference photography (https://www.facebook.com/CYMresearchconference)

C Y M


Au-delà de la vie mono-tone d’un étudiant à l’Université d’Ottawa, il

existe un monde peu connu de recherche scientifique menée par des étudiants gradués, mais aussi par des étudiants de premier cycle. Pour ceux qui en font partie, leurs se-maines sont occupées par de longues journées de travail et la chance de travailler côte à côte avec des professeurs de notre université. Bien que ce concept n’est pas propre à la faculté des sci-ences, c’est dans ce domaine qu’on peut retrouver des projets de recherche qui pourraient êtres bénéfiques à l’humanité. Malgré ça, la plupart de la population étudiante n’est pas au courant de la recherche im-portante en cours dans son propre campus et encore moins des articles publiés qui en résultent. La con-férence CYM (Connecting Young Minds) cherche à remédier cette lacune.

Étant donné que le Catalyst a été invité à cette conférence, j’ai pris un siège dans l’assemblée, ayant hâte de voir quel genre de recherche menaient les étudiants de premier cycle, et dans quelle année d’études ces jeunes scientifiques se retrouvaient. Je me suis mise à feuilleter le programme en me deman-dant si la recherche qui allait être présentée serait du même calibre que celle des étudiants gradués.

La CYM est une conférence bilingue de recher-che aux études de premier cycle, mise en place pour la première fois le 28 août 2015. Quelques mots d’ouverture ont été donnés par co-présidents Aida Ahrari et Anabel Bergeron qui ont fait référence au «connectome» humain - soit l’ensemble des connec-tions neuronales du système nerveux. C’est par l’en-tremise de ce système que nous pouvons assimiler de nouvelles informations. Celles-ci nous parviennent de nos études bien sûr, mais aussi par l’entremise de la recherche. En fin de compte, ce mot d’introduction visait à nous encourager à avoir l’esprit ouvert lors des présentations des projets de recherche.

Ce dialogue a continué grâce à quelques pro-fesseurs qui ont eux aussi donné un court discours d’introduction sur leurs expériences en recherche au niveau de premier cycle et comment cet appren-

tissage a été bénéfique pour eux. J’ai été fascinée par leurs succès académique et profes-sionnel, mais en particulier par ce qu’ils ont été capables d’accomplir à un jeune âge. Mais où sont les étudiants qui n’ont pas encore gradué?

J’ai eu ma réponse dès le début des présentations. Elles étaient d’une durée de quinze minutes, portant sur des su-

jets de niveaux de complexité différents et étaient accompagnées de présentations PowerPoint. Les projets, présentés avec beaucoup de passion, étaient variés : d’une discussion sur des traitements possi-bles de leucémie myéloïde aiguë jusqu’à l’importance de la participation des citoyens en science dans le domaine de la recherche écologique. Il y avait aussi une catégorie de présentations de cinq minutes, avec des prix pour les gagnants, sélectionnés par un comi-té de juges.

Les présentations m’ont vraiment épatées, et elles ont servies à me rappeler que ce n’est pas seulement les étudiants gradués qui contribuent au monde de la recherche scientifique. Il est possible d’en faire partie en tant qu’étudiant de premier cycle, il suffit de vouloir s’y aventurer. En fin de compte, c’est la raison que la conférence CYM a été conçue : pour rassembler les étudiants et démontrer que faire sa marque dans le domaine des recherches ne devrait pas être qu’un rêve distant pour les jeunes étudiants en science. Plusieurs étudiants de premier cycle atteignent déjà ce rêve, grâce à leurs efforts, leur dévouement à la recherche et leur passion pour leur domaine.

La conférence CYM met en vedette la recherche pendant les études de premier cycleTraduit par: Laura Goodwin

C Y M


S h e d d i n g L i g h t o n t h e B r a i n

Shedding Light on the Brain:

High in complexity and

one of most awesome-

known machine is the hu-

man brain. With this mag-

nificence comes a lot of un-

certainty; to this day, we

have barely unraveled the

mystery that is the mind,

and as a result, there con-

tinues to be many gaps in

developing neurological

treatments. One sorely un-

met need that scientists

faced in neuroscience was

the need to control specific

cells in the brain, especially

at specific times. Frequently

used electrodes and drugs

could not meet this need, as

they are neither precise nor

fast-acting enough. In the

face of this challenge, the

science of optogenetics aris-

es – the use of light pulses

in order to activate or inhib-

it specific brain cells with

lightning accuracy.

The complex technolo-

gies used in optogenetics

today arose from humble

inspiration, such as from the

microorganism Chlamydo-

monas reinhardtii. The algae

have an organelle called an

‘eyespot’ which contains

proteins that open in re-

sponse to blue light. From

there, researchers extracted

DNA that codes for these

proteins, and inserted it into

neurons. Now, there are sev-

eral proteins which are used

for this purpose, namely

halorhodopsin, bacteriorho-

dopsin, and channelrhodop-

sin. They can be controlled

by connecting the organism

to a fiber optic cable.

However, optogenetics is

only just a budding field

within the last decade. It was

a latecomer in science be-

cause many believed that

this sort of technology

would never be feasible. One

of the reasons is because the

proteins were predicted to

be toxic to mammalian cells.

As well, scientist were

searching for a method

without any dependence on

any other factors, and these

microbial opsins require a

chemical co-factor called all-

trans retinal to absorb the

photons. However, both of

these concerns were proven

to be trivial since these mi-

crobial opsins have been

shown to be non-toxic, and

experimentation has indi-

cated that vertebrate tissue

already naturally contains

all-trans retinal.

One of the many reasons

why optogenetics is taking

the field of neuroscience by

the storm is due to the myr-

iad of neuropsychiatric dis-

eases to which it has the po-

tential to tackle. Patients

with disorders such as

schizophrenia and autism

have been shown to have

altered gamma oscillations

in the brain. Through con-

trolling parvalbumin neu-

rons, it is possible to regu-

late these oscillations with

the use of light. Additionally,

symptoms of anxiety have

been alleviated by optoge-

netically resolving a specific

intra-amygdala pathway.

Even extremely complex

symptoms of depression

have been simply alleviated

when tested with this new

research. As a precise and

rapidly-responsive branch of

science, the applications of

optogenetics are endless – it

is just a matter of time until

this explosive new tech-

nique in neuroscience could

become a treatment stand-

ard in neuropsychiatric care.

The Emergence of Optogenetics

Cassidy Swanson, 1st year

BIO

Cassidy Swanston, 1st year BIO


C o m m e n t a r i e s

Opinion and Commentaries:

Even if someone is not centered at the Faculty of Science, they’ve prob-ably heard of genetically modified organisms (GMO) by now. We see “GMO-free” labels on food products, read about the March Against Mon-santo protests, and hopefully, see the applications of the medical technol-ogy brought to us through research involving genetic modification (GM). The strictest regulations are currently set in a predominant part of Europe, while Canada allows a relatively less-restricted use of genetic modification, though still appropriately regulated. In fact, Canada is one of the world’s largest producers and the larger exporter of genetically modified canola.

While a certain extent of caution is appreciated by the public, some governments might be taking the issue too sternly. In a recent example, the small central European country of Slove-nia has just passed a law, majorly restricting the use of genetic modification in research itself, despite the known benefits and crucial discoveries that have stemmed from this technology.

There are some very widespread misconceptions that underlie the hyped concerns with re-gards to genetic modification. Some general ones that came up during the campaigns in Slove-nia and their corresponding truths are summarized below:

The facts: Genetic engineering-assisted agriculture is by far more efficient, and is used by several countries that lead the world economy. By falling back to tradi-tional, “old-fashioned” farming methods, it can be argued that Slovenia has further hindered its productive capacity and must now rely on imports from those exact countries.

The facts: Several misleading articles falsifying or overstating the effect of GMOs on health (e.g. the famous Seralini rat study) have been debunked. Unfortu-nately, the negative perception printed in people’s minds is difficult to reverse, and the many medical breakthroughs they helped achieve (e.g. insulin, antibiotics, vaccines, and many more) are often ig-nored.

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Want to contribute? Veuillez contribuer? Find out more at/découvrez comment à https://uocatalyst.wordpress.com/submissions/

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X

N

Image source goes here if I need it


Stop Seeing GMO as an OMG

The facts: Actually, using GM tech-nology has allowed an improved efficien-cy of production in industry, agriculture and medicine, and reduced the need to use more harmful processes. An example of this is Bt-corn, where the genetically inserted pest repellant eliminated the need for harmful pesticides. Its sole ef-fect is on the insects which it targets.

The facts: This type of gene transfer has such an unlikely probability that it is not quite worth fearing. Nevertheless, the extent of preventative control currently being practiced restricts even the smallest chance.

The facts: With the growing popula-tion and increasing environmental and health concerns, genetic engineering can provide some crucial solutions, from de-veloping greener, more efficient industrial production, to aiding and accelerating medical research, to improving crop yield and nutritional value. Golden rice, for ex-ample, was actually a non-profit project developed to combat health issues arising from vitamin A deficiency in developing countries. Medical technology and pre-ventive information can help avoid ex-pensive treatment.

This is certainly not a complete and in-depth list of all the possible, usually un-necessary fears associated with genetic modification. To present the reality to a wider audience, experts are reaching out through various networks and social me-dia. The “Truth About GMO” group was recently created for uOttawa students on Facebook, so please be welcomed to join in on any interesting discussions that might pop up there!

Want to read more about GM foods? Stay tuned for the next Food Science article!

By VERONIKA CENCEN – M.Sc. candidate in Biomechanical Engineering

C o m m e n t a r i e s


Les traitements anticancéreux modernes comme la chimiothérapie sont souvent ineffica-ces et très toxiques. Par conséquent, la recherche se penche de plus en plus à inculquer des méthodes moins dangereuses et invasives pour traiter le cancer. Par exemple, depuis

quelques décennies, la photothérapie est utilisée pour détruire les lymphomes T cutanés super-ficiels. Le principe général de la photothérapie consiste à introduire dans le corps des matériaux photosensibles capables de se fixer aux tumeurs puis de les illuminer à l’aide de faisceaux. Ils vont alors générer des radicaux libres qui sont toxiques et mortels pour la cellule cancéreuse. La présence d’oxygène et de lumière sont des conditions sine qua non à la photothérapie, son utilisation se restreint donc aux zones superficielles du corps et celles accessibles par endoscope. Ceci est pourquoi les progrès dans ce domaine ont stagné depuis des décennies.

Cependant, des chercheurs de l’école de Médecine de Université de St Louis à Washington, ont réussi à contourner ce problème grâce à la nanotechnologie. Cette technique consiste non plus à illuminer par faisceau la tumeur, mais plutôt à apporter la lumière in-vivo à l’aide de nano livraison. Tout commence par un mélange de sucre radio-marqué appelé fluorodéoxyglucose (FDG) et de nanoparticules de dioxyde de titane (TiO2) sensibles à la lumière qui est ingéré par le sujet malade. Suite à cela les cellules tumorales qui sont exigeantes en énergie consomment ce sucre, et grâce au fluor radioactif contenu dans le FDG, elles deviennent fluorescentes en produi-sant un rayonnement Tcherenkov. Ce rayonnement est assez puissant pour activer le TiO2 qui, en bout de chaine, générera les radicaux libres anti-tumoraux. Malgré le fait qu’elle n’ait été testée que sur des rats, cette nouvelle méthode a cependant prouvé son efficacité en doublant le taux de survie des individus traités par rapport aux non traités. Les chercheurs ont aussi brillamment re-marqué qu’un complexe moléculaire de FDG, de TiO2 et de médicaments anti-cancéreux accroit la précision et la puissance thérapeutique en augmentant le taux de survie par 3 et en réduisant la taille des tumeurs par un facteur de 8! Il faut aussi noter que cette nouvelle technique serait plus saine et moins invasive puisque qu’elle requiert des doses de médicament largement plus faibles que ce qui serait administré pendant une chimiothérapie.

En ce qui concerne les effets toxiques que pourraient engendrer la lumière et le matériel photosensible, Nalinikanth Kotagiri le premier auteur de l’étude affirme qu’ils sont minimes. En effet, la lumière et le composant photosensible sont tous deux conçut pour viser la tumeur de manière très précise et éviter ainsi les tissus sains aux alentours. Les chercheurs préparent prochainement un essai clinique sur des sujets humains en combinant le FDG et le TiO2 à des médicaments anticancéreux expérimentaux, dans le but de valider cette nouvelle technique qui semble d’ores et déjà très prometteuse.

La nanotechnologie photoémettrice au profit de la lutte contre le cancerPar Kevin Amélété, 3ème année BIM; Johanne Mathieu, 3ème année BIM; Hadjar Saidi 3ème année BCH

L a n a n o t e c h n o l o g i e


The issue of climate change has been

highly publicized as a cataclysmic and global

phenomenon. The focus has been on the major

contributors, like carbon dioxide emissions

from burning fossil fuels. Other contributors

however, which one might consider to be fairly

minor and less impactful, can be much more

problematic when observed on the regional

scale. The amount of green space in our cities

may seem almost inconsequential when com-

pared to the large scale de-forestation and

desertification seen around the world, but the

real time impact on human health is becoming

increasingly apparent (Stone Jr. & Rodg., 2001).

Beating the Heat by Greening the Street Battre la chaleur par l’écologisation de la rue

Le problème du changement climatique a été grandement médiatisé comme un phéno-mène cataclysmique et mondial. L’accent a été mis sur les contributeurs majeurs, tels que les émissions de dioxyde de carbone provenant de la combustion de combustibles fossiles. Cepen-dant, d’autres contributeurs que l’on pourrait considérer mineurs et ayant moins d’impact peuvent être beaucoup plus problématiques lorsqu’ils sont observés à l’échelle régionale. La quantité d’espaces verts dans nos villes peut sembler presque sans conséquences par rap-port à la déforestation et la désertification à grande échelle vu partout dans le monde, mais l’impact en temps réel sur la santé humaine est de plus en plus apparent (Stone Jr. & Rodg., 2001).

4th year GEO traduit par

keep reading Z

Traduit par: Laila Fazal

B e a t i n g t h e H e a t


The problem arises from urban areas being

covered with impervious surfaces, which are

surfaces that do not allow water to pass

through them. This is important since moisture

can help alleviate heat. These surfaces include

paved sur-faces like roads, sidewalks, as well as

buildings, which are all generally dark in col-

our. Dark colours absorb more light energy

than lighter colours, causing them to be hotter.

In the northwestern United States, it has been

found that cities are 7-9°C hotter than their

rural neighbors (Voil., 2010). This is because

vegetation holds moisture, and thus diffuses

some of the heat. Vegetation plays such a large

role that in cities surrounded by arid or desert

regions, the measured heat island effect is sig-

nificantly reduced because temperatures inside

the cities more closely match those outside.

To better understand this issue, the US Na-

tional Aeronautics and Space Ad-ministration

(NASA) compiled temperature data from thou-

sands of cities and population settlements

world-wide. Data was initially inadequate, com-

ing from land-based sensors that were prone to

local bias, due to an uneven distribution of

these sensors. NASA responded to this problem

by doing what they do best: launching some-

thing into space. They utilized the Moderate

Resolution Spectroradiometer (MODIS), an in-

strument on their Aqua Terra satellite, and in

cooperation with the United States Geological

Survey (USGS) Land-Sat satellite, they used in-

frared Imaging to detect heat in and around

cities around the world (Lo, Quatt.. & Luva.,

1996.) They found that climatic factors did not

account for all discrepancies. For example,

Providence, Rhode Island and Buffalo.

Le problème survient des zones urbaines recouvertes de surfaces imperméables, qui sont des surfaces qui ne permettent pas l’eau de passer à travers la surface. Ceci est grave car l’humidité peut aider à diminuer la chaleur. Ces surfaces incluent les surfaces pavées comme les routes et les trottoirs, ainsi que les bâti-ments, qui sont aussi généralement de couleur foncée. Les couleurs foncées absorbent davan-tage l’énergie lumineuse que les couleurs claires, les obligeant à être plus chauds. Dans le nord-ouest des États-Unis, il a été constaté que les villes sont 7 à 9°C plus chaudes que leurs voisins ruraux (Voil., 2010). En effet, cela est dû à la végétation qui retient l’humidité, diffusant ainsi une partie de la chaleur. La végétation joue un si grand rôle que dans les villes entou-rées par des régions désertiques ou arides, l’effet d’îlot de chaleur mesuré est significati-vement réduit puisque les températures à l’intérieur des villes correspondent de plus près à ceux de l’extérieur.

Pour mieux comprendre ce problème,

l’Administration nationale de l’aéronautique et

de l’espace (NASA) a compilé les données de

température à partir de milliers de villes et co-

lonies de la population à travers le monde. Les

données étaient initialement inadéquates, pro-

venant de capteurs terrestres qui étaient su-

jettes à des préjugés locaux en raison d’une ré-

partition inégale de ces capteurs. NASA a ré-

pondu à ce problème en faisant ce qu’ils font le

mieux; lancer quelque chose dans l’espace. Ils

ont utilisé le Radiomètre spectral pour image-

rie de résolution moyenne (MODIS), un instru-

ment sur leur satellite Aqua Terra, et en coopé-

ration avec le satellite Land-Sat de l’Institut

d’études géologiques des États-Unis (USGS), ils

ont utilisé l’imagerie infrarouge pour détecter

la chaleur dans et autour des villes à travers le

monde (Lo, Quatt.. & Luva., 1996). Ils ont consta-

té que, bien que les facteurs climatiques soient

importants, ils ne tiennent pas compte de tous

les écarts. Par exemple, Providence, IR et Buffa-

lo. continuer à lire Z

FILLER

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NY sont deux villes du nord-est des États-Unis avec une taille similaire et milieux écolo-giques, mais Buffalo a tout de même une tem-pérature moyenne supérieure de 7.2°C. La NASA a isolé la couverture végétale et le modèle ur-bain comme le déterminant majeur sur la for-mation des îlots de chaleur. Avec l’aide de l’imagerie par satellite et les dossiers fiscaux municipaux, il a été constaté que les villes à faible densité et d’agencements tentaculaires ont un plus grand îlot de chaleur urbain que celles à haute densité. Une mauvaise planifica-tion de la ville augmente aussi les problèmes de circulation, ce qui produit beaucoup de chaleur. Plus de végétation (en particulier des grands espaces verts, des arbres bordant les rues et des jardins) sur les toits peut aider à refroidir ces villes en fournissant de l’humidité et en couvrant les couleurs sombres. Benedicte Dousset, un scientifique qui étudie ce problème à l’Université de Hawaii croit que « il n’y pas une seule solution, et ça va être différent pour chaque ville. Les îlots de chaleur sont des phé-nomènes complexes3 ».

Cependant, il vaut la peine de trouver des solutions, puisque ce phénomène affecte à la fois la consommation d’énergie et la santé hu-maine, avec des conséquences potentiellement mortelles. Certaines populations sont plus à risque que d’autres pendant les vagues de cha-leur, comme les personnes souffrant d’asthme, de maladies cardiaques, et les personnes âgées. La vague de chaleur à Paris en 2003 a causé une hausse de la moyenne du taux de mortalité de la ville, allant de 50 décès/jour à presque 350 décès/jour, alors que les températures avaient dépassé 45°C. L’utilisation accrue du climati-seur produit plus de chaleur à l’extérieur, exa-cerbant le problème pour les personnes sans climatiseur. Il est estimé qu’il y avait 4800 dé-cès évitables à Paris et plus de 70 000 en Eu-rope l’été de la tragédie, les personnes âgées étant les plus touchées. L’Agence américaine de protection de l’environnement (EPA) estime que plus d'Américains sont tués dans des vagues de chaleur que dans des ouragans, des foudres, des tornades, des inondations et des tremblements de terre combinés2. Avec de telles consé-quences terribles, il vaut la peine de planter quelques arbres.

,New York are both northeastern US cities

similar in size and ecological backgrounds, yet

Buffalo is 7.2°C higher in average temperature.

NASA has identified vegetative cover and urban

design as the major determinant on the for-

mation of heat islands. With the help of the

satellite imaging and municipal tax records, it

was found that cities with low density and

sprawling layouts have a greater urban heat

island than those with high density. Poor city

planning also increases traffic problems, which

output significant excess heat. More vegetation,

particularly from large greenspaces, trees lin-

ing streets, and rooftop gardens can help cool

these cities by providing moisture and cov-

ering up dark colours. Benedicte Dousset, a sci-

entist on this issue at the University of Hawaii,

believed “there’s no one solution, and it’s go-ing

to be different for every city. Heat islands are

complex phenomena” (Voil., 2010).

Solutions are worth pursuing since the heat

island phenomenon affects both energy con-

sumption and human health, with some poten-

tially deadly consequences. Certain populations

are at a higher risk than others during heat

waves, such as those with asthma, heart condi-

tions, and the elderly. The 2003 Paris heat wave

saw the city’s average mortality rate jump from

50 deaths per day to almost 350 deaths per day,

as temperatures surpassed 45°C. The increased

use of air conditioning (AC) generated more

heat outdoors, exacerbating the problem for

those with-out AC. It is estimated that there

were 4 800 preventable deaths in Paris and

over 70 000 in Europe that summer, with the

elderly being the most impacted. The US Envi-

ronmental Protection Agency (EPA) estimates

more Americans were killed in heat waves than

in hurricanes, lightning, tornados, floods, and

earthquakes combined (Stone Jr. & Rodgers,

2001). With such dire consequences and need to

reduce the heat density, it is worth planting a

few trees.



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Hello Scarcely Sleeping Student,Even though the odd all-nighter here and there will not kill you, it is not likely to help you out as much

as you think. That bad case of the munchies you will get throughout the night and the next day are not just boredom, they are actually hormones such as ghrelin, an appetite stimulant, and leptin, an appetite suppressant, that have been thrown for a loop. As a result, you may feel hungry, over eat, and potentially result in weight gain.

While you are probably planning on using your all-nighter productively to cram for a mid-term or final, the lack of sleep actually negatively impacts your ability to form and retrieve memories, so you will be less likely to remember your studied material on the exam.

Additionally, all-nighters trigger an elation effect, otherwise known as a natural chemical high from the neurotransmitter serotonin, which will give you a false sense of confidence, and potentially lead to risky behaviours. Your body’s adrenaline and cortisol levels also rise from lack of sleep and the stress that it induces. This makes it even tougher to concentrate! Stimulatory drugs such as caffeine or Adderall may seem like tempting solutions to these problems, but they only temporarily relieve your feeling of drowsi-ness before leaving the rest of your brain impaired.

When you take all of this together, the lack of sleep prevents your brain from working as well as it can while rested. There is a reason they say that driving tired can be just as dangerous as driving impaired; writing exams or assignments are no different. While it is tempting to think you can catch up on sleep the next night, sleep specialists say it could take weeks to make up for your lost sleep, and that returning to a normal sleep schedule is the most important way to recover.

Finally, a regular sleep schedule is also the best way to save your GPA. According to sleep research-ers at St. Lawrence University, sleep deprived students had lower GPAs than their well-rested class-mates. So hit the hay, your body and your GPA will thank you.-Darwin

Dear Darwin, are all-nighters really all that bad for you, aside from being tired in the morning?-Sincerely, Scarcely Sleeping Student

Dear Anonymous,In the world of anatomy and physiology, abomasum is the fourth chamber of the stomach in ruminant

animals, which are mammals with four compartments of the stomach instead of one. Examples of rumi-nants include cattle, sheep and goats. Through the use of their specialized stomachs, ruminants are capa-ble of obtaining the nutrients they need from plant-based foods. These plant products undergo fermentation in the stomach before digestion.

Thus, the function of the abomasum is to perform the chemical breakdown of food, and to do so it must secrete hydrochloric acid and pepsinogen. The abomasum structure is found on the abdominal floor of ru-minants and is composed of simple columnar epithelial tissue. A fun fact about the abomasum structure is that it is particularly large in newborn ruminants.-Darwin

Dear Darwin, what is an abomasum?-Anonymous

By: Tianyue Angela Dou, 1st Year, BIM andElizabeth Anne Richardson, 5th Year Co-op Option, BIM


Dear Fizzy Friend,I feel that it is important to first and foremost elaborate on what exactly consists of a carbonated bever-

age. Strictly speaking, a carbonated beverage is defined as a drink that contains carbon dioxide dissolved in the liquid. Typically, properties of carbonated drinks would include its fizzy texture, bubbling in the liquid, and last but not least, that incredible feeling of an ice cold carbonated drink running down your throat on a hot summer day.

Now you might be asking Fizzy Friend, why I am reciting all this information that you most likely already know? The reason is simple, that the term ‘carbonated drink’ is simply too general to deem it good or bad for your body. There are many types of carbonated drinks in the world, from sodas, to root beer, to ginger ale, to carbonated water, and it is certain to say that certain types of those beverages are more harmful to the body than others.

I’m sure you have been told that Coke or Sprite is bad for you, but is the dissolved carbon dioxide inside truly the cause? The answer leans towards: NO. Despite myths that carbonated water leeches calcium from bones or teeth, there is yet to be much real, concrete evidence to suggest the validity of such statements.

However, studies related to the consumption of carbonated soda drinks have been linked to low bone mineral density. Thus, it is safe to say that among carbonated drinks, there is no harm in enjoying a bottle of Perrier every so often, especially if you enjoy the texture of bubbly as opposed to plain water. Yet, my advice to you, Fizzy Friend, would be to cut back on the Coke, Sprite, or root beer as such drinks have been consistently found to contain too much sugar. Additionally, its high phosphoric acid content is likely a bigger factor for low bone mineral density than carbonated water.

Hope this helped and have a great day!-Darwin

Dear Darwin, why are carbonated beverages bad for me? -Sincerely Fizzy Friend

Salut Éudiant privé de sommeil, Même si passer une nuit blanche de temps en temps ne te tue pas, ceci ne t’aide en rien. Manger trop de

casse-croûte le lendemain d’une nuit blanche n’est pas forcément à cause de l’ennuie– en fait, les hormones ghréline, un stimulant de l’appétit, et leptine, un inhibiteur de l’appétit, sont entièrement déséquilibrées, dû à un manque de sommeil, ce qui te donne envie de manger. Il se peut même que tu grossisses. Bien que tu croies bien faire en étudiant tard pour un intra ou examen final, tu ne fais qu’altérer ta mémoire. Ainsi, lors de l’examen, tu auras beaucoup de difficulté à te rappeler ce que tu as lu le soir précédent.

En plus, les nuits blanches déclenchent un effet d’exaltation associé à la libération de sérotonine qui te donne un faux sentiment de confiance ce qui peut mener à des comportements risqués. Le manque de som-meil augmentera aussi les niveaux d’adrénaline et du cortisol ce qui provoque le stress, rendant la concentra-tion encore plus difficile ! Les drogues stimulantes comme la caféine et l’Adderall semblent être les solutions à ces problèmes (fatigue, stress, etc…), mais elles offrent un soulagement temporaire et provoquent la détério-ration du cerveau. Mettons tout ensemble, le manque de sommeil empêche ton cerveau de bien travailler. On considère que la conduite en état de fatigue est aussi dangereuse que la conduite en état d’ivresse. En quoi écrire un examen quand on manque de sommeil est-il différent?

Bien que tu croies être capable de compenser ton manque de sommeil, les scientifiques disent que cela pourrait prendre des semaines pour compenser le sommeil perdu. Bref, un horaire de sommeil régulier est la meilleure façon de sauver sa santé ainsi que sa moyenne (scolaire). Selon les chercheurs à l’université St. Lawrence – les étudiants privés de sommeil avaient des moyennes inférieures par rapport à leurs camarades bien reposés.

Alors, va au lit, ton corps et ta moyenne te remercieront. -Darwin

Cher Darwin, à part de se sentir fatigué le lendemain matin, passer des nuits blanches, est-il grave pour la santé? -Cordialement, Étudiant privé de sommeil