Author: Eileen Zhu

Chemical Secrets Behind Dragon Beard Candy

The Georgia Tech STEMcomm VIP team had the Taste of Science festival on March 12, 2018. During this event, my group (members from Georgia Tech SASE) and I decided to make dragon beard candy. Now let’s see the steps of making it and some science knowledge behind it.

Materials:

corn starch, corn syrup, white sugar, vinegar, peanuts and sesame

Step 1

Pour 1kg white sugar, 100 g corn syrup, 2 cup of water, 2 tea spoon of vinegar into the pot and boil in medium fire for 30-40 min, do not stir!

Step 2

Pour the caramelized syrup out and wait until it gets cool down. Put the candy into corn starch and start pulling. First of all, drill a holein the enter of candy to make it look like the shape of donut. Then make the hold bigger and start folding and double the strands.

Step 3

Tear down 5 cm of candy strands, put peanuts and sesame inside of the candy strands and wrap it up.

During the process of making dragon beard candy, the most difficult step is the boiling part. Our first time, we didn’t understand the purpose of making caramelized syrup. Also, we didn’t know the function of the vinegar so we only used less than 1 teaspoon so we didn’t make our candy too sour. Then we boiled about 20 minutes and poured the sugar syrup out even though it didn’t change color. We even put it into refrigerator for 5 hours, but it was still too soft and sticky to make it into any shape.

After discussion, we decided to boil it for a longer time than the first time and surprisingly, we found the color of the syrup slowly changed to gold and yellow after 30 minutes, and then it turned into red and brown. Then we suddenly realized that the purpose of this step is to let the white sugar get caramelized.

White sugar is actually sucrose. When we heat sucrose solution, it first gets boiling. Keep heating, thermal decomposition reaction happens. Sucrose decomposes into glucose and fructose. At a high temperature, caramelization happens. According to the science of cooking, “ Caramelization is the oxidation of sugar and a type of non-enzymatic browning reaction. As the process occurs, volatile chemicals are released producing the characteristic caramel flavor. The reaction involves the removal of water (as steam) and the break down of the sugar. The caramelization reaction depends on the type of sugar. And the caramelization temperature about 160 C, 320 F. ” [1] Thus, the reason why we failed the first time is that we didn’t boil for long enough.

What’s more, based on the sugar property study, the inversion reaction is accelerated by the presence of acids (low pH) or by some enzymes. This reaction will accelerate with increasing acidity and increasing temperature. [2] This tells us why we should put 2 teaspoons of vinegar in order to accelerate the chemical reaction.

Citation

[1] http://www.scienceofcooking.com/caramelization.htm

[2] Knecht, R. L. “Properties of sugar.” Sugar (1990): 46-65.

April 19, 2018
Sleeping Position Matters

When I woke up today, I found that my neck and shoulder were extremely sore. I was totally fine last night before bed and I didn’t have any strenuous exercise yesterday. I started to think that maybe sleeping position matters. Everyone has a favorite sleeping position, but what are the pros and cons of your favorite ones?

Face down is my favorite sleeping position, but it is actually this position that caused my neck and shoulder soreness. The prone position prevents the relaxing of the spine and also adds extra forces to muscles and joints. These extra forces make us feel very sore, numb or even tingly at some parts of body. The prone position is especially dangerous for babies According to a research study from Tasmania, Australia, the major contributing factor to the recent SIDS rate decline in Tasmania has been the reduction in the proportion of infants usually sleeping prone. [1] What’s more, a study about occurrence and mechanisms of sudden oxygen desaturation in infants who sleep face down had a conclusion that rebreathing in prone sleeping infants is associated with an increased frequency of episodic desaturations. Desaturation may result from respiratory pattern changes such as brief apneas often associated with evidence of behavioral arousal or failure to increase ventilation in the face of rising inspired carbon dioxide, also associated with behavioral arousal. [2]

The lateral position is also a common sleeping position of mine. In contrast to prone, lateral position is good for our spine since it ensures the extension of spine. What’s more, lateral position is also good for people who are struggling with sleep apnea. A experiment about effect of sleep position and sleep stage on the collapsibility of the upper airways in patients with sleep apnea showed that The results indicate that collapsibility of the upper airways is not mediated by sleep stages but is strongly influenced by body position. As a consequence lower nCPAP pressure is needed during lateral positions compared to supine positions. [3]

Supine position is the easiest but the most uncommon position for me. So I was surprised to find that supine position actually has advantages for preterm infants. A experiment about the effect of prone and supine position on sleep,apneas and arousal in preterm infants concludes that it is important to recommend supine sleeping after neonatal unit discharge for prematurely born infants because very prematurely born infants studied before neonatal unit discharge sleep more efficiently with fewer arousals and more central apneas in the prone position. [4]

Citation

[1]Dwyer, T., Ponsonby, A. L., Blizzard, L., Newman, N. M., & Cochrane, J. A. (1995). The contribution of changes in the prevalence of prone sleeping position to the decline in sudden infant death syndrome in Tasmania. Jama, 273(10), 783-789.

[2]Patel, Aloka L., et al. “Occurrence and mechanisms of sudden oxygen desaturation in infants who sleep face down.” Pediatrics 111.4 (2003): e328-e332.

[3]Penzel, Thomas, et al. “Effect of sleep position and sleep stage on the collapsibility of the upper airways in patients with sleep apnea.” Sleep 24.1 (2001): 90-95.

[4]Bhat, Ravindra Y., et al. “Effect of prone and supine position on sleep, apneas, and arousal in preterm infants.” Pediatrics 118.1 (2006): 101-107.

February 16, 2018
Are skin care products really useful?

There is a saying that everyone can be a beauty and it seems true more than ever in today’s world. Nowadays, both boys and girls are taking skin care more seriously to make their skin smooth and to look young and pretty. A recent study showed that skin texture plays a significant role in the judgment of female facial beauty. [1] Thus, it is not surprising that a girl can accumulate tons of bottles of skin-care products on her dressing table. Even boys at least have one facial cleanser. In my own experience, I use a various of skin-care products because my face gets oily and grow pimples and acne easily. I need to be extra careful since my skin is so sensitive that if I don’t choose the right products, it turns red and itchy. I do worry about if there are some side-effects and whether these countless skin-care products that come from different regions all over the planet are useful or not.

Let’s look at our skin structure first. There are three layers called the epidermis, the dermis and hypodermics in our skin. The layer skin-care products contact most is the epidermis, which it the outermost layer of skin, providing a waterproof barrier and creating our skin tone. What’s more, there are two layers of epidermis, the living basal layer, which is next to the external stratum corneum, or horny layer, which is composed of dead, keratin-filled cells that have migrated outward from the basal layer. Most of the exfoliators and cleanse products are dealing with the stratum corneum layer.

Thus what skin care products actually can do is basic moisturizing, which is a totally physical function rather than chemical. Looking at the ingredients of moisturizing products, it is not hard to find mineral oils, synthetic oils, plant oils in order to soften and moisten skin. Glycerine and propylene glycol are used for moisture absorption. These ingredients help skin to stay smooth by preventing the loss of water and oxidization.

Another important skin product is sunscreen and cream for isolating the UV and atmosphere pollution or dust. Krysta Biniek, a researcher in Stanford University wrote that “Although the ubiquitous presence of solar UV radiation in human life is essential for vitamin D production, it leads to skin photoaging, damage, and malignancies solar UV radiation poses a double threat to skin by both increasing the biomechanical driving force for damage while simultaneously decreasing the skin’s natural ability to resist, compromising the critical barrier function of the skin”[2] .

Products like skin whiteners have some serious side-effects. There is one study that showed that skin-lightening creams contained higher concentration of the studied metals than the moisturizing creams. Also, people who use skin-lightening creams are potentially exposed to higher concentration of metals. Last but not least, chromium was found at concentrations that can induce allergenic contact dermatitis in pre-sensitized individuals.[3] Based on this finding, the ingredient of skin whitening products become extremely crucial. So next time when you go shopping, remember to take a look at ingredient list. Natural sources are much better than chemicals. There is also a scientific analysis that discusses advantages of natural sources. It says that “Although a number of hypopigmenting products have been developed, those from natural sources are preferred and will predominate in the cosmetics market. More active compounds such as phenols, flavonoids, coumarins and other derivatives have been identified from natural sources. This article summarized natural skin whitening products involving tyrosinase blockers like phenols and polyphenols, and non-tyrosinase blockers like α-MSH, melanosome transferase and cytokine inhibitors.”[4] All in all,don’t forget to take a look at ingredients of skin whitening products when you are shopping.

Generally if you want to have a glowing skin, the easiest way is try to get a nice DNA at the very beginning of your life. Just kidding! Don’t be fooled by flowery words in advertisements and stay away from those products which have impossible crazy functions. You can surely earn a great skin by choosing suitable skin product and clean, moist and put sun cream everyday. So I guess the magic to have a nice skin is your perseverance.

[1]Fink, Bernhard, Karl Grammer, and Randy Thornhill. “Human (Homo sapiens) facial attractiveness in relation to skin texture and color.” Journal of Comparative Psychology 115.1 (2001): 92.

http://dx.doi.org/10.1037/0735-7036.115.1.92

[2]Biniek, Krysta, Kemal Levi, and Reinhold H. Dauskardt. “Solar UV radiation reduces the barrier function of human skin.” Proceedings of the National Academy of Sciences 109.42 (2012): 17111-17116.

http://www.pnas.org/content/109/42/17111.short

[3]Iwegbue, Chukwujindu MA, et al. “Safety evaluation of metal exposure from commonly used moisturizing and skin-lightening creams in Nigeria.” Regulatory Toxicology and Pharmacology 71.3 (2015): 484-490.

http://www.sciencedirect.com/science/article/pii/S0273230015000173

[4]Lin, Jen-Wen, et al. “Natural products with skin-whitening effects.” Journal of food and drug analysis 16.2 (2008).

https://search.proquest.com/docview/1282142799?pq-origsite=gscholar

November 10, 2017
Uncanny Valley

Savannah

One month ago, my boyfriend and I went to Savannah for a visit. I’ve always heard there are a lot of nice little stores down pedestrian streets there. As a girl who has no resistance to delicate handicrafts, I couldn’t miss this great opportunity to buy something. Just when I was totally lost in those beautiful pictures and objects, my boyfriend dragged me to the corner of the shop with a mysterious smile. “Look!” He said while pointing to a sculpture. When I glanced at that direction, I couldn’t help exclaiming under my breath. It was a small sculpture of a child’s head. But “he” was so vivid that I almost believed that the two glass beads that made blue eyes on his face were real! Even my boyfriend refused to touch the sculpture because he was so terrified by its similarity to real person.

Savannah Railroad Museum

After learning about this hypothesis, I finally understand my fear of those creepy dolls, which are one of the most popular characters in scary movies. Also, this is why I don’t like mannequins and there are a lot of ghost stories about them, too. As a result, A lot of shops use mannequins that only have body or an abstract oval “head” without face features to make sure that customers will feel comfortable. It may explain why a lot of people have fear for clowns and why toy factories seldom design dolls that are totally the same as real people.

One classic example of avoiding uncanny valley is Disney cartoon movies. Disney has created many lovable cartoon characters like Pinocchio, Cinderella, and Snow White. Looking at these cartoon characters, we donot feel any revulsion, we actually have affinity for them. What’s more, most audiences were crazy about robot characters like Baymax, WALL-E and EVE. Their huge success also proves the importance of applying uncanny valley hypothesis. Because when the appearance of a robot is made more human, obervers’ emotional responses to the robot become increasingly positive and empathetic, until it reaches a point beyond which the response quickly becomes strong revulsion.

However, some people may still have questions. Why do we love those humanlike robots in TV series West World then? This is because the hypothesis also says as the robot’s appearance continues to become less distinguishable from a human being, the emotional response becomes positive once again and approaches human-to-human empathy levels. So the uncanny valley is actually a range between a “barely human” and “fully human” entity.

And according to research, reducing consistency in human realism increases the uncanny valley effect. What’s more, this effect was stronger when realism in the eyes, eyelashes, and mouth was low, just like the example in this picture.[2] people in second column have extreme big eyes, which elicit the strongest eerie and revulsion (or uncanniness) feelings in viewers among three columns.

There are a lot of hypotheses to explain the existence of uncanny valley. Some people believe that uncanny valley is the outcome of long-term evolution and is a typical emotional response of stranger avoidance theory. Avoiding unusual individuals is a way to protect ourselves. Humans sense and avoid those who look not normal because they seem unhealthy or might have a hereditary disease. As a result, when an object makes us feel it is neither human nor a typical robots we instinctively have feelings of aversion and fear.

Park in Savannah

But based on the evidence of other researchers, it seems that realism inconsistency theory is the best way to explain uncanny valley. Because this theory explains cold, eerie feelings elicited by transitions between instances of two different, mutually exclusive categories, given that at least one category is anthropomorphic: Cold, eerie feelings are caused by prediction error from perceiving some features as features of the first category and other features as features of the second category. What’s more, in principle, it can explain not only negative evaluations of transitions between real and computer modeled humans but also between different vertebrate species.[3]

Savannah Local Food

No matter which theory is right, we now understand that our uncomfortable feelings for nonliving things that seem human are a result of the uncanny valley. So if you are frightened by scary creepy doll movies or clown masks in the future, just tell yourself, it is all because of uncanny valley, totally science, no big deal and you will be fine.

Savannah trip

Work Cited

Ho, Chin-Chang, and Karl F. MacDorman. “Measuring the Uncanny Valley Effect.” International Journal of Social Robotics 9.1 (2017): 129-139.

MacDorman, Karl F., and Debaleena Chattopadhyay. “Reducing consistency in human realism increases the uncanny valley effect; increasing category uncertainty does not.” Cognition 146 (2016): 190-205.

MacDorman, Karl F., and Debaleena Chattopadhyay. “Categorization-based stranger avoidance does not explain the uncanny valley effect.” Cognition 161 (2017): 132-135.

Image

p1,p2, p7, p8, p9 credit by Erting Zhu

https://commons.wikimedia.org/wiki/File:Wpdms_fh_uncanny_valley_3.jpg

https://commons.wikimedia.org/wiki/File:Repliee_Q2.jpg

https://azzai.deviantart.com/art/FRA-LA-LA-LA-LA-494506133

https://www.flickr.com/photos/53554756@N02/6804196816

Edited by professor Jennifer Kraft Leavey

Written by Erting Zhu

September 16, 2017