I have been trying to get rid of my pimples for the past two years. It has gone worse and I have tried multiple acne removal products. I was using one product in Shanghai and when I went to India for Christmas break, I switched my acne gel again. My grandma, who claimed that she had never experienced acne breakouts in her life, told me that I’ve been putting too many products on my face and this is actually making things a lot worse for my skin. For the first time, it hit me. I was putting way too many products on my face and didn’t even think about what I was putting and how much I was putting. That got me thinking about what are truly in these products and how they are affecting my skin. I thought about Laurie’s blogpost about petroleum jelly and realized that many of us have a lot of misconceptions about face cream and gel. I wanted to clear things up for myself, so I did my own research. I found out that most acne products have this chemical called benzoyl peroxide. My question is to what extent is benzoyl peroxide effective for acne treatment?
Acne is caused by the overproduction of sebum, which is an oil produced by the sebaceous glands in our body. The oil travels from the sebaceous glands to the follicle, where the skin hair grows. When there is too much oil in the follicle, the pores on your skin gets blocked and forms a bump on your skin. This area becomes an ideal place for bacteria to grow, exacerbating the bump on your skin. (Chase, B.).This bump is known as a pimple.
I’m sure some of you have heard of brands like Neutrogena, Ponds, and Garnier. They offer topical products to help fight those acne on your skin. If you’ve used some of these products, your skin has definitely been exposed to a chemical called benzoyl peroxide or BP (May, E. 2013). You’re probably wondering, how does this chemical work to remove pimples? BP works like an antibiotic as it kills the bacteria in your clogged pores. When BP comes into contact with your skin, it decomposes into benzoic acid and oxygen (Chase, B.). This is because the oxygen-oxygen bond in the structure has a very weak bond and can easily break when it comes into contact with the skin. When this bond breaks, free radicals form from the oxygen atoms. These free radicals are then attached to the sebum lipid. The bacterium that causes acne is called Propionibacterium Acnes and it is known to be anaerobic, which means it can only thrive in the absence of oxygen. The oxygen derived from BP causes the bacteria to die as it provides an oxygen rich environment within the infected area (G, Susan 2010). Pimples grow because the sebum blocks the pores, and therefore, oxygen and allows for these bacteria to infect the pimples.
Looking at the mechanism of BP surely tells us that it is an effective chemical for killing the bacterial growth within our pimples. However, I’ve been using products that contain BP but am still not experiencing any changes in my skin. I still get pimples. With that being said, I realized that perhaps it’s not about how much BP and what brand I need to put on my skin. I must understand my skin characteristics and what my skin needs in order to fight acne. Since every skin is different, not everyone can cure his or her acne with BP.
BP can cause skin irritation, dryness, and peeling which are some of the things I have experienced but have just ignored because the problems were so minor. Regardless, they did happen and never solved my acne problems. I recently experimented the amount of acne gel I put on my skin and how much dryness it would cause. I found that when I do put more and more acne gel, my skin would feel even dryer. This tells me that BP isn’t entirely bad, but I just needed small amounts of it to protect my skin from getting too dry. This speaks to some of us who naturally have dry skin. Do not use too much acne gel (ones with higher BP concentrations) if you have dry skin! If you don’t have skin that is too dry, BP can be an ideal medication for your pimples since it does remove the mixture of sebum and exfoliate the dead skin cells (Chase, B.).
It’s crucial for us to truly get to know the types of skin products we use as they can have a significant impact on our skin. I was simply putting on lots and lots of BP on my skin and causing my skin to experience unnecessary stress. One thing I learned for sure is that during puberty, which a lot of us are still experiencing now, our hormonal changes encourage sebum production and thus pimples are quite inevitable. However, getting to know your skin type is the first step to solving your acne problems.
During the summer holiday, my family and I visited a large cave in the Malaysia. The cave was a famous tourist attraction as there were thousands of bats living in the cave. As we walked along the elevated walkway in the cave, the guide began to talk about the history of the cave. He said that in the past, people used to collect guano in the cave. As he said that, the guide shined his flashlight on the cave floor, and I realised that I could not see it at all, as it was covered in a thick layer of bat feces. The guide then explained that people collected guano for fertiliser and even used it to make fireworks. After he said that, I thought why would people want to go all the way to a cave just to collect bat droppings for fertiliser, and how can bat droppings be used to make fireworks. When I returned to Shanghai, I decided to do some research to find out what chemical properties of guano made it such a valuable fertiliser and how could it be used to make fireworks.
Based on my research, I found that the reason why guano could be both a fertiliser and a component in explosive is because of the rich amounts of various nitrates (NO3– )in it. Nitrates are polyatomic ions that have a trigonal planar structure, with the nitrogen atom as the central atom.
As mentioned earlier, guano was valued as an extremely efficient fertiliser because of the high amounts of nitrates in it. (Wikipedia). Nitrates contain nitrogen, which is an extremely important element for not only plant life but also other organisms as well because it is the main component of amino acids and nucleic acids, which is used to make DNA and other essential proteins. However, the element nitrogen itself cannot be broken down and used by plants as nitrogen molecules are held together by extremely strong triple bonds. Therefore, nitrogen has to be reduced into various nitrates. This is why nitrates have a negative charge to indicate a gain of electrons. Plants get these nitrates naturally from the soil. By adding fertilisers such as guano, the nitrate concentration of the soil increases, therefore increasing plant growth. These nitrates include potassium nitrate KNO3 , sodium nitrate NaNO3 and others.However, though guano used to be mined and collected in the past, today these nitrates are produced synthetically. For example, potassium nitrate is produced when sodium nitrate and potassium chloride are reacted together in a decomposition reaction.
NaNO3 (aq) + KCl (aq) → NaCl (aq) + KNO3 (aq)
Sodium nitrate is produced in a acid-base reaction with nitric acid and soda ash
2 HNO3 + Na2CO3 → 2 NaNO3 + H2O + CO2
However, while fertilisers containing nitrates greatly promote agricultural growth, the excessive use of them has a negative impact on the environment. When the excess fertilsers get washed away into freshwater lakes and rivers, eutrophication occurs, in which there is an excessive growth of algae. The algae deplete the surrounding waters of oxygen, killing the marine life in it (Schindler, David, Vallentyne, Joh R, 2004).
As to the reason why guano is used to make fireworks, the answer is because nitrates are powerful oxidisers (Earl, 1978). Oxidisers are essential in explosives as it provides the oxygen needed to fuel the explosion (Earl, 1978). This is because as mentioned earlier nitrates are reduced fro nitrogen. As we have recently learnt, oxidizing agents are often the ones that had been reduced. Nitrates are often used as oxidisers because of the energy released from the triple bonds of nitrogen.
From my research on guano I realised how chemistry can be used to benefit and harm society. Using chemistry to isolate and mass produce nitrates in synthetic fertilsers from guano boosts agricultural production. However, these fertisers pollute the environment. Understanding the chemical properties of nitrates lead to the development of powerful explosives that can be used for peaceful purposes such as mining or harmful purposes such as terrorism. In conclusion, knowledge in chemistry can be used to benefit our lives and also identify potential threats.
Earl, Brian (1978), Cornish Explosives, Cornwall: The Trevithick Society
Schindler, David and Vallentyne, John R. (2004) Over fertilization of the World’s Freshwaters and Estuaries, University of Alberta Press
Sometimes at night I see my mother drinking sleeping pills before she goes to her bed. She complains that she is unable to sleep well these days because of stress. Similarly, I have difficulty sleeping too, and it is irritating when you are really tired and your body wants to rest but you can’t just fall asleep. So I once asked her if I could have a tiny piece of the tablet she usually takes, but just as I thought, she said no. She told me that it will cause addiction and it is bad for our body health. Indeed, people get dependent to sleeping pills just like drugs, and I knew that people sometimes give themselves fatal overdose to commit suicide. However New York Times reported that although the US Food and Drug Administration has not approved any sleeping pills for use by children, an estimated 180,000 Americans under age 20 take prescription sleep aids anyway. (Join Together, 2005) Let’s take the teenagers who are physically close to adults aside, but wouldn’t that be harmful for the little kids?
Sleeping pills are one of the sedatives that depress the central nervous system of the human body. Over the counter sleeping pills contain antihistamine, which is the same medication found in allergy medicine. To produce sleepiness, antihistamine does the opposite of histamine, which releases a neurotransmitter to produce awakeness. Antihistamine contains diphenhydramine hydrochloride or doxylamine succinate, and both ingredients send a signal to the brain to depress the central nervous system. (Fryer, n.d.) To be more specific, the neurotransmitter, gamma-Aminobutyric acid (commonly known as GABA for short) is the primary inhibitory neurotransmitter in the brain that tends to cause the brain to “calm down”, and the active ingredients in the sleeping pill reduces the ability of nerves by altering a cell’s membrane potential causing less neuronal activity. (Terix, n.d.) Furthermore it also influences the levels of tryptophan, serotonin (a calming neurotransmitter), melatonin (a sleep-inducing hormone). This in turn leads to relaxation, relief from anxiety, induction of sleep, and suppression of seizure-activity.
However, there is a reason why sleeping pills are said to be bad for our health other than problems arising from addiction and withdrawal symptoms. Many studies have found connection between regularly taking sleep aids and an increased risk of death and cancer. One study discovered that “those who took 1 to 18 pills of any sleep aid or hypnotic medication per year had a greater than three-fold increased risk of early death. Heavy hypnotic users were 35% more likely to develop a new cancer.” (Oz, 2013) There are no clear explanations for this connection, however the connection between the use of sleeping pills and the risks of suicide and risky behavior, such as impaired driving, is quite obvious.
By looking at these facts it is natural that parents keep their children away from taking one. However, it is not just adults who suffer from sleeping disorders such as insomnia. Synthetic Melatonin supplements have been used as a solution for helping restless children sleep. Melatonin is a hormone found naturally in human body that helps control the sleep-wake cycle, and its natural levels in the blood are highest at night. (Therapeutic Research Faculty, 2009) Lights tend to decrease production of melatonin, causing the body to stay awake, which explains why people sleep well in dark rooms rather than in well-lit rooms. The supplements appear to have a good safety records, and have successfully corrected the sleep-wake cycle of a blind child with multiple disabilities too. Since melatonin comes from natural hormones, the side effects are milder compared to those sleeping pills that contains antihistamine.
However it doesn’t mean that melatonin has no bad side to it, and doctors believe those supplements should only be used for the most serious sleep and neurological disorders. Still, some doctors say that parents are missing the point and give their children melatonin supplements when they don’t need to. One mother has confessed that at night she “lines up her six healthy children nightly to give them their melatonin pill” because she is stressed out from taking care of her children after the hard work she had done that day. Dr.Ditchek in New York University School of Medicine is concerned that the melatonin supplement may interact with other hormones in the body, potentially affecting fertility or sexual development, and further study is necessary for the serious problems that melatonin may have. (Wallace, 2013)
In this stressful world, sleeping pills have an undeniable appeal to people who suffer from sleepless nights. However after this research I realized that we should try not to use nor rely on them because natural things are best for our body health and sleep isn’t an exception. It is important to be aware of both beneficial and harmful side of what we use in our daily lives. In conclusion, people should try to change their life habits (like stay away from coffee and PC before sleeping) before they reach for their sleeping pills.
Join Together. (Nov 16,2005). Many Kids Taking Sleeping Pills. In The Partnership at Drugfree.org. Retrieved from
I was watching the Discovery Channel the other day and came across a show about steel. Living in today’s technologically advanced era often leads me into thinking that cars, boats, bridges, pots and pans are very ordinary, but I’ve never realized just how ubiquitous steel is (or the fact that steel isn’t an element). I was so intrigued by steel that day that I actually sat for over an hour to watch the show. So how is steel made and why is it used so widely? Curious, I decided to learn more about steelmaking and hope to provide some insight into this ‘ordinary’ material.
Steel is essentially an alloy of iron, the second most abundant metal on Earth (Iron Fact-ite, n.d.), and 0.5 to 1.5 percent concentration of carbon (Brain & Lamb, 2000). It is used widely for its strength, durability, affordability, flexibility, and recyclability. What got me interested was also the connection between its manufacturing process and redox reactions, which is what we are currently learning about in IB Chemistry.
The two visuals below sum up steelmaking in a nutshell.
To make steel, coal is first converted to coke, or pure carbon, as a source of energy for the blast furnace, where iron ore is turned into molten iron and limestone is added. Inside the blast furnace, carbon and carbon monoxide act as reducing agents in reducing iron (III) oxide, the ore, into iron. Because carbon is above iron on the reactivity series, carbon, being more reactive, is oxidized and iron is reduced, as seen below. (Brown, n.d.)
In the next stage, the molten iron is mixed with recycled steel and alloys based on the customers’ needs. This then enters either a basic oxygen furnace, where 70 percent iron is mixed with 30 percent recycled steel, or an electric arc furnace, where 70 to 100 percent recycled steel is used (Making Steel, n.d.). The molten steel produced is then sent to a slab caster to be casted into solid steel slabs, which is later reheated to ensure that the slabs were all at the same temperature before being rolled into strips. The steel slabs then go to the roughing mill and finishing mill, which reduces the slabs’ thickness and rolls them into strips, and become hot rolled products. Then hydrochloric acid (HCl) is applied to remove surface scales before the steel strips are cooled, and now they are ready for sale for construction, automotive, appliances, and manufacturing. (Steel Builds a Better World, n.d.)
I found steel’s manufacturing process rather interesting, but what was more also interesting was the fact that steel is 100 percent recyclable and can be “recycled infinitely without ever affecting its strength or durability” (Steel Builds a Better World, n.d.). As someone who cares about environmental health, I was very happy to know about this. In fact, manufacturing using recycled metals not only reduces greenhouse gas emissions but also saves up to 56 percent the energy used to make steel from iron ore. Moreover, it is also beneficial to the economy in that in 2008 alone, the “scrap recycling industry generated $86 billion and supported 85,000 jobs” (West, n.d.).
On the other hand, however, iron and steel manufacturing also raises environmental concerns. The iron and steel industry release air pollutants, such as sulphur dioxide, nitrogen dioxide and carbon monoxide, and particulates, such as soot and dust, into the air. Moreover, steel works also releases large volumes of wastewater, which, if retained in unsealed ponds, may contaminate other local water ecosystems. Additionally, the consumption of 21.1 gigajoules per tonne of energy (used by US scrap-based plants in 1988) also brings up the issue of energy conservation. (Spiegel, n.d.)
I realized that it is important to consider both merits and shortcomings before reaching conclusions. As much as steel is useful and recyclable, its manufacturing also harms our environment. This research was an eye opener for me as I found a real-life application, steelmaking, for what we’re learning in class!
Brain, M., & Lamb, R. (2000, April 1). How Iron and Steel Work. HowStuffWorks. Retrieved October 9, 2013, from science.howstuffworks.com/iron4.htm
The Chemistry of Steelmaking. (n.d.).School Science. Retrieved October 9, 2013, from resources.schoolscience.co.uk/Corus/14-16/steel/msch1pg1.html
West, L. (n.d.). Metal Recycling – Benefits of Metal Recycling – Why Recycle Metal?.Environmental Issues – News and Information about the Environment. Retrieved October 9, 2013, from http://environment.about.com/od/recycling/a/metal-recycling.htm
Steel Finishing Flowline. (n.d.). Steel Works. Retrieved October 9, 2013, from www.steel.org/Making%20Steel/How%20Its%20Made/Steelmaking%20Finishing%20Flowline.aspx
Steelmaking Flowline. (n.d.). Steel Works. Retrieved October 9, 2013, from www.steel.org/Making%20Steel/How%20Its%20Made/Steelmaking%20Flowlines.aspx
Since last year I have been supplementing my workouts with protein powder. I believe that the gains I have obtained while supplementing my workouts with protein powder were achieved at a faster rate than when I worked out and received all my nutrients from the food I ingested. Getting my protein powder at first was really difficult because my father was seriously against me putting “unnatural” supplements into my body. It took a little convincing but I manage to buy my first protein powder 1 year and a half ago. Without truly looking into the details of protein powders, I based my purchase off of the supplement store manager’s recommendation, and bought myself an “All Natural Whey Isolate” Protein Powder! This protein powder was more expensive than all of the other powders in the store (should have rang some bells), but the manager assured me that it’s because this protein powder is all “natural”. I know from a light research done in the past that whey protein powder is derived from milk, therefore I wonder if the production of protein powder involved anyother materials (other than milk) , and if so are they also naturally occurring or manufactured in some lab.
Whey is a bi-product of cheese and casein manufacture. When 100 L of milk is used to produce cheese and casein, generally 12 kg of cheese is made, along with 3kg of casein, and 87 L of whey. This bi product named whey is definitely not the same Whey protein powder, which I put in my protein shake. This whey is 6% solid, and is a greenish liquid, which looks and tastes unimaginably horrible. This is why in the past whey was used as pig food and fertilizer and sometimes the whey was simply discarded into the ocean.
Whey Protein Concentrate is produced using ultrafiltration. Ultrafiltration keeps in a liquid product retentate, which consists of any insoluble material or solutes greater than 20000 Da molecular weight. The rest of the whey (greenish liquid) passes through the membrane and is called the permeate. The permeate consists of most of the lactose and H2O originally found in the whey. The retentate, which consists of only 1-4% of the original whey inserted into the ultrafiltration, is then spray dried into a powder that consists of 35-85% protein depending on the intending customer.
Digestive enzymes in a controlled environment manufacture whey Protein Hydrolysates, where the temperature and pH levels are controlled. Raw materials from Whey Protein Concentrate are used. The WPC raw materials are filtered and spray dried in the same way regular WPC are made, after which they are subjected to the digestive enzymes. A regular protein is a chain of amino acids in which the amine group of one amino acid is bound to the carboxylic group of a neighboring amino acid via a amide bond. Proteolytic enzymes catalyst the hydrolysis of these bonds. Chains of 2 to 5 amino acids are called peptides. In a hydrolysate, all the proteins are broken up into peptides and free amino acids no greater than the peptides.
Figure 1 Protein Hydrolysis
The research I performed has shed a new light on the substance I drink almost three times a day. This research has not only proven to me that chemistry is truly everywhere but has also shed some light onto the economical side of protein powder production. In conclusion the production of whey protein concentrate is “all natural” by that I mean that it involves only milk, which has been ultrafiltrated. The production of protein powder hydrolysate in my opinion is also “natural” because large amino acid chains are broken up using digestive enzymes, which are naturally occurring. The economical perspective of protein production comes from the fact that from 87 liters 3.48 liters of protein powder.
“The Chemistry of Whey Protein – www.ChemistryIsLife.com.”www.ChemistryIsLife.com. N.p., n.d. Web. 8 Oct. 2013. <http://www.chemistryislife.com/the-chemistry-of-whey-protein>.
“Minimal whey protein with carbohydra… [Appl Physiol Nutr Metab. 2007] – PubMed – NCBI.” National Center for Biotechnology Information. N.p., n.d. Web. 8 Oct. 2013. <http://www.ncbi.nlm.nih.gov/pubmed/18059587>.
As a student who is passionate about studying psychology, I came across an article on the University of Cambridge’s research site that talks about Alzheimer’s disease, which can be defined as “a progressive disease that destroys memory and other important mental functions”. The article, titled “Better hygiene in wealthy nations may increase Alzheimer’s risk,” argues that there is a strong positive correlation between clean, industrialized countries and the prevalence of Alzheimer’s disease in the countries’ population. (Fox, 2013) While I was initially fascinated by this claim, I knew that I needed to be a little more objective when trusting these relatively one-sided claims. In doing so, then, I formulated the following question: To what extent does hygiene actually contribute to the development of Alzheimer’s disease? In other words, is there a direct cause-effect relationship between cleanliness and Alzheimer’s or is there simply a correlation between the two?
To me, the article seems to suggest that Alzheimer’s Disease (AD) is caused by high sanitation levels within a country because of limited contact with certain bacteria, viruses, and other microorganisms. Deficiency of contact with these microorganisms, they claim, can lead to an insufficient amount of T-cells, which are a form of white blood cells that effectively counteract “foreign substances and disease” (Apple dictionary). The resulting inflammation that occurs from a lack of T-cells is linked to the inflammation that is commonly found in the brains of Alzheimer’s patients. (Better hygiene in wealthy nations may increase Alzheimer’s risk, 2013) So in searching for a clearer answer to my question, I knew that I needed to understand the differences between the brain of an AD patient and a healthy brain, and break them down to their elemental, molecular level to understand exactly what could be the root cause of AD.
The brains of Alzheimer’s patients are characterized by 3 “hallmarks”: an abundance of amyloid plaques, an increase in neurofibrillary tangles, and the destruction of and loss of connection between the nerve cells. (National Institutes of Health, 2011) From this, I thought that perhaps the excess of amyloid plaques could be linked to the lack of T-cells in an Alzheimer’s brain. From here I came across a scientific study that related T-cells to the amyloid-beta proteins (that make up the plaques), and I found that “chronic stimulation by the amyloid-beta protein present in the blood” could be the cause of changes in the T-cells of AD patients that otherwise make us immune to bacteria and other microorganisms. (Mariavaleria et al., 2011) I then came across a second scientific study that claimed that T-cell immunity to bacteria and other microorganisms in AD patients decreased significantly in comparison to the T-cell immunity of healthy patients. (Giubilei et al., 2003) This research seemed to tell me that hygiene may not be the direct cause of AD, but rather that the build-up of amyloid-beta proteins in our brain could be a biological cause.
I followed through with this prediction – that the build-up of amyloid-beta proteins in our body causes AD – by trying to find out where the amyloid-beta protein comes from. Interestingly, I found that there are actually three types of amyloid-beta proteins that are processed from what is called the amyloid precursor protein (APP), which is found widely within the cells of our own bodies. Two types of amyloid-beta proteins (amyloid-beta 38 and amyloid-beta 40) are benign while the third type of amyloid-beta protein (amyloid-beta 42) is toxic and seems to be the one that causes brain damage in AD patients. (Khan) After identifying the type of amyloid-beta protein, then, I came across its chemical structure:
The molecular formula for amyloid-beta 42 is C203H311N55O60S (chemBlink); clearly, I can see that the molecular structure is quite large. It is also characteristic of a protein, as evidenced by the presence of primary, secondary, and tertiary amides that are part of the molecule. I found that this protein may actually be responsible for damaging the blood-brain barrier by making it more permeable. (Sharma et al., 2012)
From this, I thought that maybe the increase in permeability of the BBB could be linked to a less immune brain, which could connect back to the “hygiene hypothesis.” So I then decided to go back to investigating the immune system’s role in AD pathology by connecting it to its relation with the amyloid-beta 42. I found that the amyloid-beta 42 activates the production of one type of T-cells that “secrete pro-inflammatory cytokines, which cross the BBB and directly activate microglia and astrocytes in the brain, as well as indirectly induce inflammation by activating dendritic cells.” (Town et al., 2005 as cited in Fox et al., 2013) Microglia and astrocytes are “cellular components of the brain’s immune network” (Cohen, 2009); hence, I observe that T-cells modify the performance of these components in the immune system, which fosters the development of AD.
So in answering my question, I find that the amyloid-beta protein and the immune system of the brain are bidirectional in developing AD, and both play significant roles in the pathology of AD. That means that our immune system’s response to different levels of hygiene, along with our genetic predisposition (the presence of APP) both can contribute to increase risk in Alzheimer’s disease.
What are the implications, then, of my findings about AD? Well, since AD is the 5th leading cause of death for those aged 65 and older (Alzheimer’s Association, 2013), understanding the causes of AD can help us better find cures for this disease, which are not entirely ready as of yet. For example, realizing that the blood-brain barrier has increased permeability in AD patients tells drug developers that treating AD involves strengthening the blood-brain barrier so it does not allow toxic substances (such as cytokines) to enter and trigger inflammatory responses. (Sharma et al., 2012) In addition, after researching more thoroughly into the claims of the initial reading on AD, I now understand that certain claims can often turn out to be monochromatic and therefore they must be taken with a grain of salt. The health and diet claims that are so prevalent on the web must be, in my opinion, scrutinized and considered comprehensively in order to be trusted, especially since our well-being is directly at risk.
All in all, my investigation on AD has taught me more than just causes or effects of the disease. My findings have led me to understand that critical evaluation and rational judgment (the weighing of pros and cons) is often necessary when we are faced with decisions to make the best choices, both for ourselves and for our society.
Fox, M., Knapp, L.A., Andrews, P.W., & Fincher, C.L. (2013). Hygiene and the world distribution of alzheimer’s disease. Evolution, medicine, & public health, 2013(1), doi: 10.1093/emph/eot015
Giubelei, F., Antonini, G., Montesperelli, C., Sepe-Monti, M., Cannoni, S., Pichi, A., & Tisei, P. et al., US National Library of Medicine, National Institutes of Health. (2003). T cell response to amyloid-beta and to mitochondrial antigens in alzheimer. Retrieved from PubMed.gov website: http://www.ncbi.nlm.nih.gov/pubmed/12714798
Sharma, H. S., Castellani, R.J., Smith, M.A., Sharma, A., US National Library of Medicine, National Institutes of Health. (2012). The blood-brain barrier in alzheimer’s disease: Novel therapeutic targets and nanodrug delivery (10.1016/B978-0-12-386986-9.00003-X). Retrieved from PubMed.org website: http://www.ncbi.nlm.nih.gov/pubmed/22748826
Ever since I was little, my mom always made sure that I put on sunblock before going outdoors. She correctly believed that the purpose of sunblock was to prevent skin cancer, which according to the American Cancer Society is actually “the most common of all cancers, accounting for nearly half of all cancers in the United States”. (2013). Now, as a habit, I wear sunblock every day before going outdoors for cross-country practice. My teammates make fun of me for being “paranoid”, but I think that taking precautions is important; I do not want skin cancer! I always argue about the importance of sunscreen. Thus, you can imagine the shock when I read an article called “Your sunscreen might be poisoning you” by Dr. Perry, an Adjunct Associate Professor at Columbia University on the Dr. Oz TV show website. I was a bit hesitant about the reliability of claims from the Dr. Oz show, (an American TV talk show hosted by Dr. Oz, a teaching professor at Columbia University) since I assume from experience that TV shows are often more for entertainment and may misrepresent the truth. As a result, to clarify whether I have been poisoning myself for sixteen years, I decided to research the chemistry of sunblock: what are some common ingredients? How do they work? And most importantly, do they really harm us?
According to the University of California San Francisco School of Medicine, there are two types of active ingredients in sun blocks: physical, which “reflect or scatter UV radiation before it reaches your skin” and chemical, which “work by absorbing the energy of UV radiation before it affects your skin.” (2013).
According to Dr. Elizabeth Hale of the Skin Cancer Foundation, the most common physical sunblock used is either zinc oxide or titanium oxide. (n.d.) In a sense, applying them is almost the equivalent of applying white paint, as they literally “block” the sunrays. (Hale, E. n.d.) For example, as seen in the image, zinc oxide is literally a white powder.
These physical sunblock ingredients absorb both UVA and UVB rays, which is known as “broad spectrum” (a term you should look for on your sunscreen labeling!) and are large enough particles that they do not enter into your bloodstream. (Hale E., n.d.)Thus, they are both harmless and effective. The drawback, however, is that they are not so visually pleasing unless you want to have a white layer on your face. I researched my own Avene sunblock and found it to be a physical sunblock; it is indeed very white are hard to spread apart—something I found annoying at first, but now I’m glad that at least I’m being effectively protected from the sun.
The consumers’ natural preference of a sunblock that wasn’t so “whitely” visible like a layer of paint on their faces therefore led to the development of chemical sunblock—and this is where the problem begins. One common chemical ingredient is called oxybenzone, which is a chemical that absorbs UV rays. It is so common, that according to a CNN article, “56% of beach and sport sunscreens contain the chemical oxybenzone.” (Dellorto D., 2012).
Dr. Perry’s article on the possible poisonous effects of sunblock was referring to oxybenzone; he claimed that as an endocrine disruptor (an external compound that disrupts the physiological actions of our body’s natural hormones)(Aguirre C., n.d.), it “can cause abnormal development of fetuses and growing children… early puberty… low sperm counts and infertility… the development of breast and ovarian cancers…prostrate cancer…”. (Perry A., 2013) After reading this, I immediately looked for other sources’ claims on oxybenzone to confirm Dr. Perry’s claim. First, the CNN article referenced before reported that “The American Academy of Dermatology maintains that oxybenzone is safe.” (Dellorto D., 2012) After this, I thought, “Okay, so the government thinks that oxybenzone is safe. Then is this the Environmental Working Group and Dr. Perry crazy?”This is when I came upon an article by Dr. Claudia Aguirre of the International Dermal Institute, which shed light on the studies causing people to blacklist oxybenzone. One study showed that the harmful effects of oxybenzone were done on rats that were ingesting oxybenzone in toxic amounts. Another study was on whether the chemical would penetrate deep into the dermis in the first place, and although the answer was yes, the study was done on skin samples in a lab—not on human beings. Finally, another study on oxybenzone “saw deleterious effects on humans”, but “the participants were asked to use about 6 times the recommended amount of sunscreen needed to prevent sunburn”. (Aguirre C., n.d.). Thus, in the end, Dr. Perry’s claim is true—but only if you use a crazy amount of sunscreen with oxybenzone.
After doing this research, I learned a lot about sunscreen, and I think it was interesting to research the chemical ingredients in our everyday products. I had always assumed that sunscreen was just some “magical” skin cancer preventer! Also, an important implication from this research is that we should never immediately trust claims made by articles online, even if the author, like Dr. Perry, is an adjunct professor at Columbia University. We should look more in depth into the studies that the claims are based on, and decide whether we want to use these products. Dr. Perry was too extreme in his claim, which confirms my initial assumption that people on TV shows tend to exaggerate and cannot always be trusted. Thus, we have to be careful to what extent we should believe in others’ claims, and of course, we should continue to use sunblock (use the recommended amount of the equivalent of a shotglass, or two tablespoons, to the face and body) (Hale, E., n.d.)!
One of the videos that particularly struck me from Chemistry class was “Bioethanol,” from the Periodic Table of Videos. In the video, Professor Poliakoff discusses his travels in Brazil, a country known for its high use of ethanol fuel, as well as his discovery regarding the use of bioethanol versus common gasoline. He found that while Brazilians domestically produced an abundant supply of ethanol fuel for use, most citizens continued to use regular gasoline to fuel their cars because it was more cost-effective (meaning that their cars could run on more kilometers per gallon with gasoline than with ethanol, and the difference in price between the two fuels was minimal). Poliakoff then went on to provide an economic explanation for this – because ethanol is fermented from sugar, and because sugar is also consumed in the diet, there is an increasing demand for sugar in both industries. Thus, the costs of producing bioethanol from sugar increase, and in turn, its price as a fuel increases. He then briefly mentioned that an alternative to using sugar in the production of ethanol could be cellulose, a material that is not specifically used for food (Haran, n.d.).Upon mentioning this, he piqued my interest and I decided to further investigate bioethanol and cellulose. This brought me to my question: How is bioethanol manufactured from cellulose, and to what extent is the use of cellulosic ethanol a cost-effective solution to preserve our environment?
To begin, I conducted background research on bioethanol, otherwise known as ethanol. Ethanol, whose chemical formula is C2H5OH, belongs to the chemical family of alcohols. It is “a colorless liquid and has a strong odor.” (European Biomass Industry Association, n.d.) A number of incentives have fostered the use of ethanol as an alternative fuel source. Among the most pressing of these include the increasing greenhouse gas emissions and harmful pollutants such as carbon monoxide and nitrogen oxide to the environment (Derry et al., 2008), the increasing scarcity of fossil fuel resources, and the growing dependence on foreign imports of oil (CropEnergies AG, 2011). All these concerns for developed countries, such the United States and those in the EU, that result from excessive consumption of fossil fuels contribute to the utilization of ethanol as a cleaner alternative energy source for automobiles. Ethanol releases energy according to the following equation when combusted:
CH3CH2OH (l) + 3O2 (g) –> 2CO2 (g) + 3H2O (g)
(Derry et al., 2008)
There are three main steps in manufacturing ethanol. The first is the formation of “a solution of fermentable sugars,” the second is the “fermentation of these sugars to ethanol,” and the third requires the “separation and purification of the ethanol, usually by distillation.” (Badger, 2002) Traditionally, the fermentable sugars used to produce ethanol come from either sugar crops, such as sugar cane or sugar beet, or cereal crops, such as maize or wheat (European Biomass Industry Association, n.d.). Fermentation of these sugars occurs when microorganisms, such as yeast, ferment the C-6 sugars (commonly glucose) obtained from the crops by using them as food and producing byproducts that include ethanol (Badger, 2002). However, because these sugar crops and cereal crops are also necessary for human consumption, they can be relatively expensive to use for production of ethanol.
So, a third mechanism of developing ethanol for fuel has been developed, using cellulose, the waste residues from forests and the parts of plants that are not needed for food. Also known as Lignocellulosic or Cellulosic bioethanol, this biofuel is considered less expensive and “more energy-efficient than today’s ethanol because it can be made from low-cost feedstocks, including sawdust, forest thinnings, waste paper, grasses, and farm residues (i.e. corn stalks, wheat straw, and rice straw).” (Detchon, 2007) As a person who never likes when things go to waste, I was delighted at the fact that we could create fuel from cellulose, which in turn helps to save so many of our natural resources and eliminate much of our waste. To my dismay, however, I discovered that this advantage is accompanied with many costly limitations.
Cellulose, like starch, is composed of long polymers of glucose, which can be used for fermentation in producing ethanol. However, the structural configuration of cellulose is different from that of starch, and this, combined with its encapsulation by lignin, a material that covers the cellulose molecules, makes hydrolysis of cellulosic materials very difficult because the process requires the aid of enzymes or specific reaction conditions or equipment (Badger, 2002).
The three main methods of cellulosic hydrolysis are acid, thermochemical, and enzymatic hydrolysis (Badger, 2002). For the purposes of this blog post, I will focus on the latter form, involving enzymes, which are “biological catalysts.” Enzymes are introduced into a reaction to provide an alternative pathway with a lower activation energy so that the reaction can take place (Derry et al., 2008). However, enzymes must be able to make contact with the reactants of the reaction, which is quite difficult to achieve with cellulose molecules. Thus, a “pretreatment process” is needed to separate the tightly-bound sugars that comprise cellulose. These processes are often energy-intensive, and are thus associated with high costs (Badger, 2002). In addition, the costs of the enzymes are also currently quite high, although biotechnology research is gradually decreasing their costs (Novozymes, as cited in Detchon, 2007) The National Renewable Energy Laboratory (NREL) uses a process known as simultaneous saccharification and co-fermentation (SSCF) to hydrolyze cellulose. A “dilute acid pretreatment” to “dissolve the crystalline structure” of the cellulose is first employed. A portion of the “slurry” that results is then placed into a vessel that grows a cellulase enzyme, while another portion is placed into another vessel to grow a yeast culture (Badger, 2002). In this process, sugar conversion and fermentation occur simultaneously, rather than consequentially, to yield the product of ethanol as quickly as possible, usually a few days (Lynd, 1999 as cited in Warner & Mosier, 2008). However, SSCF still requires expensive enzymes in order to occur, and because the process lasts a few days, the reactor vessels must run for long periods of time (Badger, 2002).
So, simply from observing the process of SSCF, I realize that the industrial creation of ethanol from cellulose is a tiresome process. The reactions needed to convert a molecule of cellulose into its glucose constituents are both costly and time-consuming, contrary to what I had believed would have been quite simply a breaking down of a polymer of glucose. There are numerous implications to this issue, and this brings me to the second part of my question: to what extent is the use of cellulosic ethanol a cost-effective solution to safeguard the environment? Here I discovered the advantages and disadvantages of cellulosic bioethanol. Firstly, greenhouse gas emissions from ethanol-fueled cars are reduced by 85% to 94% compared to those running on regular gasoline. Cheap feedstock that is non-related to food materials is another added benefit of bioethanol created from cellulose, since the question of food vs. fuel is eliminated. And, much of the infrastructure adapted for ethanol fuel use is already in place – roughly 2,000 stations serving E85 (a fuel containing 85% ethanol and 15% petrol) and most automobiles are already built to run on both gasoline or ethanol-based fuel. What’s even more favorable to the environment from using bioethanol is that because ethanol is an organic compound, it is highly biodegradable, making fuel spills much less hazardous than regular gasoline spills (Green the Future, 2008).
Furthermore, the overall benefits gained from using bioethanol made from any other means also cannot be ignored – for example, lower carbon emissions, less reliance on foreign oil reserves, and conservation of finite fossil fuel resources (CropEnergies AG, 2011).
These pros do no exist without their cons, however. I also found that in addition to the high costs of production of cellulosic ethanol that may make it relatively expensive for consumers, there were other disadvantages as well. Commercialization of this type of ethanol is limited, as most production plants are pilot plants and find it difficult to transition to full-scale commercial plants. In addition, because ethanol absorbs water, it is easily contaminated as a fuel and thus is difficult to transport. The high costs of production also could not be outweighed by ethanol-run automobile performance, since it takes about 1.4 gallons of E85 to run the same distance as it would take 1 gallon of regular gasoline (Green the Future, 2008). This was also the main reason, as stated by Poliakoff, that Brazilians continued to use regular gasoline as opposed to bioethanol – their cars simply ran more efficiently on petrol.
From analyzing both sides of the argument, I have come to the conclusion that even though bioethanol seems to have its many disadvantages, the biofuel has come a long way in improving the welfare of our environment. The implications of a better environment per se are perhaps enough to convince me to purchase ethanol as the source of fuel for my car (when I get one, eventually). But also, because cellulosic materials are often wasted and abundant in nature, I find it simply fascinating that we have come across yet another resource with which to provide energy to sustain our lifestyles. Of course, though, I am careful not to jump to the conclusion that this is a panacea to the global peril of climate change, because I know that exploitation of our environment will lead to destruction of it. But now I have understood that even the smallest of steps taken to achieve ecological sustainability can have drastic rewards for the wellbeing of society.
Derry, L., Clark, F., Janette, E., Jeffery, F. Jordan, C., Ellett, B., & O’Shea, P. (2008). Chemistry for use with the IB diploma programme: Standard level. Port Melbourne, Victoria: Pearson Education Australia.
Everyday at dinner, my mother would bring Kimchi to the table. I myself am not a big fan of the taste of Kimchi, but in my opinion, my mother, like all Koreans, might be. During the SARS outbreak 11 years ago, my uncle convinced me to eat Kimchi by telling me that the reason Korea was not affected by SARS was that all Koreans ate Kimchi. 11 years later, I am still asking myself what is so special about this fermented vegetable that Koreans and a few foreigners are crazy about. So I came up with the research question for this blog post: What are the positive and negative effects of consuming fermented food, and what is the chemistry behind them?
Kimchi is not the only type of food that has been through fermentation. Our favorites such as cheese, yoghurt, and smoked salmon have also been through this process. So, to begin, what is the definition of fermented food? According to Peter Sahlin at Lund Institute of Technology, fermented food is any foods influenced by lactic acid producing microorganisms. Similarly, fermentation was categorized by the World Health Organization as a “technique for preparation/storage of food.” This is because in the developing countries, one tenth of the children below the age of five die because of dehydration because of diarrhoea caused by unhygienic conditions. In this case, lactic acid fermentation has been discovered to “reduce the risk of having pathogenic microorganisms grow in the food.” (Sahlin, 1999)
Fermentation of foods has been an ancient traditional practice. Tiberius the Roman emperor always had a barrel of sauerkraut when he traveled to the Middle East because Romans knew of the effects of lactic acid that included protection from intestine infections. (Schachter, R. ) Over the years, fermented foods have continued to be known to create beneficial probiotics to our guts. Having healthier guts lead to healthier digestion, which means having better absorption of nutrients, vitamins and minerals, improving overall health. In addition, fermented foods have helped in relief from lactose intolerance, prevention of colon cancer and prevention of reoccurrence of bowel disease. (Sisson, M., n.d.)
The beneficial effects of fermented food are caused by the lactic acid bacteria that form during fermentation which increases the acidity of the food (decrease the pH) as the bacteria convert energy from sugars and starches into lactic acid. (Erickson, Fayet, Kakumanu & Davis) Lactic acid bacteria, according to Sally Fellon, writer of Nourishing Traditions are ‘beneficial organisms that produce numerous helpful enzymes as well as antibiotic and an anti-carcinogenic substances.” (Pickl-It., n.d.) From what I have previously learned, acids such as lemon are able to kill harmful bacteria. When I connect this fact to my research, I could most likely conclude that when fermenting food, the food is not only stored at a state where harmful bacteria are not able to cultivate, but also the production of beneficial enzymes are not interfered, hence resulting in the beneficial effects of fermented food, such as improvement in digestion.
However, when fermented food are over consumed, there can be negative health impacts.
Even though aldehydes are not toxic substances, if one encounters a high toxic level of aldehydes through foods such as kombucha tea, some pickles, wine and beer, one’s health may be damaged. Aldehydes are a type of organic compound produced by fermenting organisms, or oxidation of alcohols. They commonly contaminate cigarette and other smoke such as smog, vehicle and factory exhaust, synthetic fragrances, and others. (Schachter, R., n.d.) The human body has enzymes that are able to convert the aldehydes into a less-harmful substance, but when there is a high level of aldehydes, the aldehydes can become toxic and travel to the brain, causing neurological diseases. Another harmful effect of aldehydes is that it damages red blood cell membranes. What this means is that red blood cells will become “less flexible in passing through tiny capillaries, altering hemoglobin” (oxygen transporter in RBC). In other words, there will be less oxygen available to the cells in the body, especially the brain. (Pierini, C., ASCP, C., & CNC. n.d.)
Despite that my sources suggest both negative and positive health implications of fermented food, they are not clear about the specific diseases that can be caused by the negative impacts of fermented food, but only clear about the specific diseases that can be prevented by the positive impacts. From this, I may be able to assume that the positive consequences of eating fermented food may be greater than the negative consequences, and if I would like to avoid the negative consequences, I may need to avoid certain types, such as alcohol, although this may not be a problem as I am not an alcohol consumer.
After learning about the effects of fermented foods, I realized that it was no coincidence that my mother had intestinal problems. I learned that all this time, when my mother was bringing Kimchi to dinner table, she was eating the fermented vegetable for her health rather than for the taste.
3. Pierini, C., (ASCP), C., & CNC. (n.d.). A Health-Destroying Toxin We Can’t Avoid And Must Detoxify. Vitamin Research Products. Retrieved September 16, 2013, from http:// www.vrp.com/digestive-health/a-
Growing up with a Chinese mother, one of the worst parts about getting sick wasn’t just the symptoms, but the ingestion of traditional Chinese remedies. The ginger root was (and still is) the worst one in my opinion however at the same time it was the most effective. Whenever I get sick, my mom will either make me eat solid cut up ginger root or she would put it in into Coca-Cola for me to drink and for some reason it is surprisingly effective. This got me wondering, what chemical process lies behind this home remedy and how does it work?
The ginger (Zingiber officinale) root, or rhizome, has been used as herbal medicine in its native Asian continent for thousands of years. It has been known to mainly help cure ailments such as a common cold and those involving the stomach, such as: stomach aches, motion sickness, morning sickness, diarrhea and nausea to name a few. However, it has also been known to be a pain reliever, relieving chest pain, low back pain, arthritis and muscle soreness, nature’s very own analgesic if you will. Doctor’s also prescribe ginger pre-surgery to alleviate post-surgery nausea and it is also used post-chemotherapy operations for similar reasons. 
Figure 1: Foster, S. Zingiber Officinale
Surprisingly enough, even though this natural remedy has been in use for thousands of years, scientists still don’t have a clear idea on how it acts on our body on the micro level. What is known is that the active ingredients in the ginger root are non-volatile pungent components oleoresin, grouped into gingerols and shogaols. Gingerols are a series of homologues with varied unbranched alkyl chain length, whereas shogaols are a series of homologues derived from gingerols with dehydration at the C-5 and C-4. The most active gingerols and shogaols are the 6-, 8- and 10-, gingerols and 6- shogoal.
Diagrams of 6-, 8-, 10- gingerols & 6- shogaols compared to internal standard PAV
Part of a study conducted by Yanke Yu. et,al took twenty high-risk subjects developing colorectal cancer and randomly placed them in half. Half of them would receive 250mg ginger extract and half of them would receive a placebo. The study found that 6- gingerols in particular was found in high-concentrations in the colon among high-risk sample subjects that ingested dried powdered ginger. This lead to the assumption that 6- gingerols were a necessary factor in the health of the colon and thus is being investigated as a possible treatment for patients with colon cancer.
However, despite all of the positive (albeit vague) effects that ginger has on the body, there also possible side-effects of ingesting ginger. MedlinePlus suggests that ginger affects fetal sex hormones and thus it is advised that pregnant women avoid eating ginger. Breast-feeding women, people with various bleeding disorders (hemophilia), diabetics and people with heart conditions should stay away from eating ginger. The effects of ginger interacting with prescribed medication have also raised some questions for people with similar cases as previously stated. Ginger shouldn’t be used with anti-coagulative / anti-platelet drugs as ginger “might” slow blood clotting, such medications include ibuprofen and aspirin. Medications for diabetes and high blood pressure should also not be ingested with ginger as ginger might reduce blood sugar concentration.
What vexes me most about this investigation is how vague my sources are. I find that although my question has been answered on mainly a macro level. I still do not know how the 6-, 8-, 10- gingerols and 6- shogaols interacts with various bacteria and other pathogens. However, I do observe that the structures of the gingerols and shogaols do contain an alcohol hydroxyl functional group. Drawing upon my everyday experiences and previous knowledge, I know that alcohols do have anti-septic properties and this functional group might play a role in how gingerols and shogaols interact with various bacteria and pathogens in the human body. Also, the gingerols and shogaols have a non-polar structure, I assume that this allows them to pass through blood-membrane barriers more easily than other polar substances, however this is pure speculation.
The implications of this lack of knowledge is that, until we know more about how gingerols and shogaols found in ginger interact with our bodies’ systems, we will be putting more people with colorectal cancer at risk. It has been found in the study previously stated that the gingerols and shogaols found in ginger are necessary in our bodies gastro-intestinal tract (specifically in the colon) and could play a vital role in aiding people with colorectal cancer. Also, if we know how the gingerols and shogaols interact with various pathogens and with our body in general, it could be possible to create more effective medical solutions for common day sicknesses and reduce the risk of additional side effects with other medications.
 Sabina, E.P., Pragasam, S.J., Kumar, S., Rasool, M., (2011). 6- gingerol, an active ingredient of ginger, protects acetaminophen-induced hepatotoxicity in mice. Retrived from: http://www.ncbi.nlm.nih.gov/pubmed/22088594