Chemistry Studies in Siena

What really makes a plane fly.

2009-07-09T13:33:00.001-07:00

So I’m sure that all those of us who have already made it back to the states took a plane home, and at some point while the plane was taxiing to and from the runway, or you were waiting for the slow people in front you to get their carry-on luggage and get off the plane, you looked out the window and saw some large fuel trucks. Now we all know that the fuel in there isn’t the same petrol that you put in your car, but what’s the difference?

When fuel for aviation was first deviating from gasoline used in automobiles, it was simply a matter of having a higher octane rating for the more powerful, high-performance engines used in planes. A higher octane rating means that the fuel can be compressed more before combustion, so it can be used in better engines. After the higher octane ratings were achieved, aviators wanted a safer fuel with a higher flash point. The flash point is the temperature at which something can catch fire when exposed to an open flame. Gasoline is a mixture of hydrocarbons ranging from 4 to12 carbons per molecule, and it has a flash point of about 30 degrees Fahrenheit. Jet-A, the kerosene-based commercial jet fuel, was developed which contains hydrocarbons which have anywhere from 5-15 carbons. This fuel has a flash point of 100 degrees Fahrenheit. This fuel can take the compression in jet engines, and is less likely to catch on fire. So the main lesson to take away from this is if you’re ever fueling up a plane, don’t use gasoline.

http://en.wikipedia.org/wiki/Jet_fuel
http://en.wikipedia.org/wiki/Gasoline
http://wiki.answers.com/Q/What_is_the_difference_between_jet_fuel_and_car_fuel

Mosquitoes, Shmosquitoes..

2009-07-08T18:17:00.000-07:00

As our final days in Italy come to a close, Sanet and I are enjoying a three-night stay in Venice. With the colorful people and the bustling atmosphere as hundreds and thousands of tourists roam the almost-flooded streets during high tide, we escaped the main island today for a tour of the four islands around the edge of Venice: Murano, Burano, Cimetero, and Torcello. Murano is known for its fabulous Venetian glass, Burano for its handmade lace, Cimetero for its centuries of graves of deceased Venetians, and Torcello for its miniscule population (20) and its leaning church bell tower, which leans at the same degree as Pisa’s famous torre. Way back when, Torcello was actually the birthplace of Venice. People from the mainland would settle here to avoid barbarian masses roaming the lands. But even today, you can see why not many could survive on this island- there is no fresh water, the land can't be farmed, and there is a significant number of mosquitoes. When I read this in Rick Steve’s, I had to curse these “bastard butterflies,” as our Italian friends from Siena liked to call them. Over the past two days, I have been eaten alive by mosquitoes, so I decided to look into some chemistry of how to repel these nasty buggers.
There are many products on the market that claim to repel mosquitoes, both natural and synthetic. The most common natural repellent is citronella oil, which is made from a grass that grows in Southeast Asia. The leaves are picked and dried, then steam-distilled to extract the essential oil, which is added to lotions, candles, etc. Citronellal is the main terpenoid in the oil which gives it the lemon scent it is known for. Sadly for us, citronella is not actually a very successful repellent, proven by a study published in the Journal of American Mosquito Control Association. Citronella candles and incense reduced the biting rate by less than 50%. A second study published in the same journal found that citronella was the least effective out of three types of essential-oil candles (geraniol candles reduced biting rate by 85%).
Another repellent option which has been controversial for half a century is DEET (N,N-diethyl-3-methylbenzamide).There are two possible reasons for why DEET repels mosquitoes so well. First, DEET inhibits the carbon dioxide receptors in the bugs' nervous systems, thus rendering them senseless when it comes to smell. Or, instead of jamming their senses of smell, perhaps mosquitoes just don't like the smell of DEET and would prefer to avoid it. Apparently there is a lot more research to be done on this topic. The bad news is that in larger concentrations and with longer exposure times, DEET can be toxic and lead to severe neurological problems.....

So what can I do to keep from becoming completely covered in mosquito bites? Not much since I have no idea how to ask for repellent in Italian. But it's not a big deal since we leave for Atlanta on Saturday morning, to my dismay... At least I will find solace in the fact that I have some awesome anti-itch cream waiting for me in my apartment.

Arrivederci, Italia, you will be missed.

Pharmacokinetics, formulation, and safety of insect repellent N,N-diethyl-3-methylbenzamide (deet): a review. ( http://www.ncbi.nlm.nih.gov/pubmed/8827606)

Evaluation of the efficacy of 3% citronella candles and 5% citronella incense for protection against field populations of Aedes mosquitoes. (http://www.ncbi.nlm.nih.gov/pubmed/8827606)

Indoor Protection Against Mosquito and Sand Fly Bites: A Comparison Between Citronella, Linalool, and Geraniol Candles (http://www.bioone.org/doi/abs/10.2987/8756-971X(2008)24%5B150%3AIPAMAS%5D2.0.CO%3B2)

http://en.wikipedia.org/wiki/Citronella_oil#Use_as_an_insect_repellent
http://expertvoices.nsdl.org/connectingnews/2008/08/26/after-50-years-scientists-still-not-sure-how-deet-works/

Fire-the-works-up

2009-07-08T16:49:00.000-07:00

Yet again I missed out on an opportunity for fireworks and celebration. I didn’t even have some kind of sexy drink with my all-time favorite Perspectives in Chemistry teacher, Dr. Daphne Norton. This 4th of July was a sad reminder that I have only seen fireworks on that day twice in my life. Growing up in another country and then for the last 8 years that I have lived in America, not being in the U.S. for the big day, I have missed out on a great many of these colorful night-time displays. As a tribute to my failed attempt at being patriotic this year, I will instead approach the subject of fireworks from another entertaining point; CHEMISTRY.
Every High School student spent at least one day in a chemistry class in which you could throw some different metals into a flame and watch the pretty colors. If not, then those left surely have at some point in their lives thrown some table salt into a flame and watched the effects as it burned. Throughout time the basic theory behind the chemistry has been used in many versatile ways: art, gun powder, photography, elementary science fair projects, and pyrotechnics. But what is actually happening?
Much thought goes into creating fireworks. Not only do you get different patterns in the sky and different colors, but you also get different kinds of light emitted. The colors of the fireworks come from metal compounds such as strontium (red), aluminum (white), magnesium (white), and copper (blue) among others. These can burn as either incandescent or luminescent light. The first uses light produced from heat, the second uses an energy source other than heat and thus can sometimes be called “cold light”. Incandescent fireworks give many of the orange, yellow, and white colors as increasing temperatures with different compounds. Luminescence comes from the absorption of light by an electron that becomes excited and unstable, when the electron jumps back to its stable, ground state it emits light. This principle can be used in different analytical chemistry techniques such as atomic absorption [spectra] (AAS).
The different chemical components of fireworks are as follows: an oxidizing agent, a reducing agent, a coloring agent, and binders and regulators. Because the nature of fireworks is a combustion reaction an important part of this reaction is oxygen to burn the mixtures. This is provided by the oxidizing agent, commonly nitrates, chlorates or perchlorates. Next, reducing agents burn the oxygen to create hot gasses. A combination of reducing agents can be used to speed or slow the process. Two such reducing agents are Sulfur and charcoal. The coloring agents are as mentioned, different compounds such as, strontium salts and lithium salts for red colors, aluminum, titanium, or magnesium for silver or white, and sodium compounds for yellow colors. The last two elements of fireworks are not very chemical, but rather there for the physical aspect of packaging and the resulting shapes of the fireworks.
I hope this gave some insight into the colorful and creative side of chemistry and the festivities created by its many uses.

Works Cited:

http://www.scientificamerican.com/blog/60-second-science/post.cfm?id=bombs-bursting-in-air-whats-in-thos-2009-07-03
http://chemistry.about.com/od/fireworkspyrotechnics/Fireworks_Pyrotechnics.htm
http://library.thinkquest.org/15384/chem/index.htm
http://chemistry.about.com/od/fireworkspyrotechnics/a/fireworkcolors.htm

The world through rose colored glass

2009-07-08T16:48:00.000-07:00

After the studies in Siena ended, I took the opportunity at hand and decided to visit some other places in Italy. It was on this trip that I ended up in Venice… along with the many bridges and canals, taxi boats and gondolas, there was also the wonderful variety of industry native to Venice, such as lace and glass. Not being much taken with the idea of visiting a lace factory, however exciting that may sound, I took a trip to Murano, the small island known for its beautiful creations in the glass blowing factory. I had previously visited a crystal blowing factory with the other Emory students, but Murano was a new experience for me…. Quite a few purchases into my trip, I realize just how lucrative the industry is and some further inspection told me that much of its appeal lies not just in the glass, but the use of color and gold leaf in the actual glass. From this comes my inspiration to for this blog entry: glass and color.
Just as the art of glass blowing had to develop with knowledge and skill, so too did the use of color in glass evolve over time. Colored glass was an accidental discovery, an inventive fluke deriving from impurities. Dark brown or green glass came from impurities in the sand, such as iron, or from the fire smoke, such as sulfur. This fluke lead to the resourceful use of different minerals or metal salts for coloring. Gold chloride creates ruby glass and to make a glow in the dark glass you would use uranium oxide.
Metals can be used in other ways to color glass. Adding metallic compounds to the glass can cause an iridescent effect. Or if you would like that beautiful gold or silver leaf look to the glass without worrying about the metal oxidizing or wearing away, thin layers of colloidal metals are added to the glass and then coating that with another layer of clear glass.
Most of the colored glasses involve some sort of metal oxide ‘contaminating’ the glass itself, such as iron oxide (green, brown), cobalt oxide (deep blue), manganese oxide (deep amber, amethyst), and antimony oxides (white). A lot of the finer designs, though, have other secrets that have nothing to do with combination chemistry of glass and other compounds, but instead is simply the use of glass layering a beautiful work of brushstroke or similar technique.
So next time you pick up that gorgeous green glass that your friend brought you back from Murano, ask yourself: “Is there any iron in this?”

Cited works:
http://www.sciencedaily.com/releases/2009/06/090617123435.htm
http://chemistry.about.com/cs/inorganic/a/aa032503a.htm

More Good News Involving Wine

2009-07-08T14:36:00.000-07:00

So we’ve learned all about the antioxidant capabilities of the polyphenols in wine, but what about the other health benefits of some of these compounds? One in particular, resveratrol, has been linked to many health benefits including life extension, cancer prevention, and even lowering blood-sugar levels. Resveratrol is produced naturally by plants that are being attacked by things like bacteria or fungi, but they are also found in the skins of red grapes and are therefore present in red wine.

Human testing has been limited with this compound, but it has been shown that it can extend the median life of flies, worms, and even fish by a significant amount. Animal studies have also shown that it is effective against cancer as long as it can be delivered to the necessary areas in significant amounts. The only time that a study using humans has had positive results with resveratrol was in a study that showed how high doses of it significantly lowered blood sugar levels.

The exact mechanisms of resveratrol are not well understood, but it has been shown to activate different enzymes, and in some cases, cause apoptosis (programmed cell death) which could explain some of their anti cancer properties. Although resveratrol may not end up making us live longer, cancer free lives, it does give us another reason to keep drinking red wine.

References:

http://en.wikipedia.org/wiki/Resveratrol

Boron cancer threrapy part 2

2009-07-08T04:44:00.000-07:00

I wanted to talk more about the Boron therapy for cancer that Dr Soria talked about in his class. The ideal therapy is the one in which only the cancerous cells are destroyed without damaging healthy tissue or affecting the function of important systems specially when treating brain tumors because the cells of the brain are the most sensitive and the ones with the most important function. BNCT is a technique that uses radiation to destroy the cells but the way it works is different and is much more selective because it destroys only the cells close to the target cell.
This is not the typical radiation technique since the beam does not destroy all of the tumor cells but the target cell is one which contains an isotope of boron. The key in this process is that the boron attaches to the cancer cell by attaching it to compunds that have special affinity for tumor cells.

The basic principle for the neutron capture therapy. A higher concentration of Boron exists in the tumor cells than in the nomrmal ones. Nuclides have different affinity for the thermal neutrons absoption. Of the nucleides that have this affinity B-10 is the most attractive because it is not radioactive and is very avaliable. Even if the affinity of most of the tissues is the highest for boron there are considerably amounts of nitrogen and hydrogen and its content inside the cell are significant. To avoid the presence of these undesirable isotopes the high amounts of Boron 10 are attached to the cell until the point that is saturates the cell.

Ode to Jet Lag

2009-07-08T04:07:00.000-07:00

Monday morning in Rome, Anne and I woke up at 6:30am to catch the train from Termini station to the airport. We arrived at the airport a little before 9 and my flight was scheduled to leave at 11:20. I boarded the plane around 10:30 and the plane did not take off until around 3:45pm, due to some “technical difficulties.” I landed in Washington D.C. at 7:30pm (1:30am Italy time) and waited until 10pm for my connecting flight. I finally arrived in Rochester at midnight, and arrived at my house at 12:30am (6:30am Italy time), exactly 24 hours after I had woken up in Rome. Within that 24 hour period I took 3 naps; each lasted no more than an hour. I did not actually go to sleep until almost 2am, and somehow I woke up at 4:30am. My body was completely still on Italy time, so waking up at 10:30am Italy time was apparently enough of a sleep in, despite my lack of sleep over the previous 28 hours. This got me thinking – why do I need sleep in the first place? What exactly is sleep and why couldn’t I manage to fall back asleep even though I was so tired?
The reasons for sleep are still not well understood, though sleep is always being studied. What is definite about sleep is that it gives the body time to recharge its batteries by repairing muscles and replacing dead cells. Sleep also gives the brain time to organize memories – it is believed that dreams play a role in this. A lack of sleep compromises the immune system and the ability to think clearly. Certain chemicals released in the brain are associated with sleep. Growth hormone is released in children while they sleep, and the levels of the neurohormone orexin vary greatly from sleeping to wakened periods. The level of melatonin in the body is also raised during the sleeping period.
A study done on cats showed that the levels of adenosine are directly related to sleep. Adenosine is the nucleoside that forms the core of adenosine triphosphate (ATP), the molecule that powers most of the biochemical reactions inside cells. According to the study, adenosine levels build up during waking hours and decline during sleep periods. This research suggests that the body’s regular need for sleep comes from the brain’s need to replenish low stores of energy. When an animal’s energy levels in the brain get low, levels may be restored through sleep. Rising concentrations of adenosine may be how the brain recognizes that it is running low on energy and needs to recharge. When researchers deprived cats of sleep for 6 hours, their adenosine levels were double what they had been after being awake for 2 hours. When they were finally allowed to sleep for 3 hours, the adenosine levels slowly declined. This must be why I woke up at 4:30am yesterday, despite my sleep deprivation over the previous day. My guess is that my short naps were long enough to lower adenosine levels in my brain to the point where my body’s normal sleep schedule was more important to my sleep patterns than my utter exhaustion. Oh well, luckily I have plenty of time to catch up on sleep in the next few days.
Like many of the other students did, I also would like to thank everyone for a phenomenal 5 weeks. All the amazing activities and great friendships I made definitely place this summer in my top 5. For anyone who doesn’t realize, that means this summer is rivaling with summers spent at *gasp* Jew camp! Now you all know I’m serious when I say grazie mille for making this summer unforgettable. You all rock :)

References:
http://health.howstuffworks.com/sleep.htm

http://www.sciencenews.org/sn_arc97/5_24_97/fob2.htm

http://www.chemistrydaily.com/chemistry/Sleep

A Future With Swirl-Shaped Cell Membranes!

2009-07-07T20:20:00.000-07:00

Last Wednesday, I gave a presentation on the chemical properties for the formation of patterns in nature. One of my examples involved fairly current research on the pattern formation of the lipid bilayer. I found this study truly exciting and will explain it in more detail. The Belousov-Zhabotinsky reaction (BZ reaction) involves the addition of energy to a medium containing bromine and an acid. The addition of “fuel” breaks the second law of thermodynamics and leads to the accumulation of undesirable products. Once the necessary reagents run out, the reaction reverses and regains equilibrium.

Current research on the lipid bilayer involves the addition of the BZ reaction to the lipid bilayer to alter the sandwich model. The sandwich model represents a phosholipid layer between two outer protein layers. Before the BZ reaction was analyzed for pattern formation, the integrity of the bilayer was detected through x-ray scattering. X-ray scattering reveals a sample’s shape and size through the sample’s dispersion of x-rays. The x-ray scattering results revealed that the integrity of the lipid bilayer was maintained by the addition of BZ reagents.

The next step of the experiment involved the addition of BZ reagents to observe he various pattern formations of the lipid bilayer. Each pattern was classified depending on the lipid content. The lipid content is represented by the percentage of the weight of the lipid over the total weight of the solution. The mechanism behind the BZ reaction with the lipid bilayer is not known yet. One theory involves the presence of pore-like defects in the lipid bilayer that may allow the disruption of the sandwich model for new patterns. Researchers plan to use this information as a model for patterning phenomena in nature.

Reference
Rossi, F.; Ristori, S.; Rustici, M.; Marchettini, N.; Tiezzi, E. Dynamics of pattern formation in biomimetic systems Journal of Theoretical Biology 2008, 255, 404-412.

Blingin' Security Checks please?

2009-07-07T13:31:00.001-07:00

For Dr. Soria’s presentations, I researched a lot of information on gold nanoparticle use for cancer treatment. I planned on blogging about other applications for gold nanoparticles and was intrigued by its use in toxin detection. These nanoparticles make possible a portable detection system that could scan for viruses, bacteria, and toxins used by bio-terrorists, perhaps right in the airport. However, my own personal airport TSA search coming back from Italy was not so pleasant as to include gold nanoparticles.

Nanoparticles can be conjugated to antibodies specific for the toxin in question. These probes can then be used with a very small sample of cells. Once bound, a comparison of infected cells and healthy cells should yield a dramatic difference in appearance. The difference between gold nanoparticle detection and previous methods is its portability and rapid speed. Once the nanoparticles are bound, visualization through a microscope shows cells covered with the light-reflecting probes.

A more quantitative method sometimes used is surface plasmon resonance spectroscopy, which measures the nanoparticles’ interaction with light at specific frequencies. Higher or lower absorbances mark higher or lower amounts of bound probes. Specifically for ease in toxin detection, new research has taken advantage of visible color changes. Nanoparticles are created and then coated with sugars. This weak solution is then mixed with the toxin, modified, and yields a solution with a new color. A pure gold nanoparticle solution is made at first to be red but changes blue when a toxin is present. The depth of color correlates to the concentration of toxin as well. Further research on this topic could yield almost endless possibilities. Forensic chemistry could use gold nanoparticles at crime scenes, and water sources could be determined whether safe or unsafe to drink.

References:

http://news.bbc.co.uk/2/hi/technology/4872188.stm

Issues with Radiocarbon Dating

2009-07-05T15:39:00.000-07:00

As I was flying home this weekend, I was thinking of what I could write my final blog about and I came up across the concept of radiocarbon dating in the book I was reading, Guns, Germs, and Steel. (I also came across The Shroud of Turin when I was watching the Pink Panther 2, but I didn’t think I could write a meaningful blog about such a ridiculous movie). I know that Imran had talked about radiocarbon dating in a previous blog, but I just wanted to talk about some of the problems of radiocarbon dating that were mentioned in this book.

During photosynthesis, plants intake atmospheric carbon. The ratio of carbon-14 to carbon-12, two isotopes of carbon, in atmospheric carbon is approximately 1:1,000,000. However, once a plant dies, approximately half of the carbon-14 decays into carbon-12 every 5700 years. Therefore, the date of a specific plant is based on the ratio of carbon-14 to carbon-12.

Until the 1980’s, scientists had a problem dating small materials found in archeological sites because a substantial amount of carbon needed to be collected from the source in order to determine its age. However, this problem was solved with a technique called accelerator mass spectrometry. This technique only required a very small sample and thus was vital in many historical discoveries. One example is that concept of food production. It was originally thought to originate in the Americas in 7000 B.C., but in fact, it originated in 3500 B.C.

However, another scientific discovery was that the ratio of carbon-14 to carbon-12 in the atmosphere is not always constant. This ratio changes with time. Therefore, some radiocarbon dates needed to be ‘calibrated’ with a new ratio. This was done with the help of growth rings in long-lived trees. The trees had a known specific date (based on the very accurate growth rings), and then the carbon ratio was analyzed in these trees to determine what the true ratio of carbon-14 to carbon-12 was during that age. This discovery had a strong influence on some archeological sites which were incorrectly dated based on the old ratio. Even now, other sites are still being accessed and calibrated so that the true dates of the sites can be known.

Like others, I just wanted to end this blog with a word of thanks and gratitude toward my peers and professors. I have never had an experience like these past five weeks and I will never forget it. I truly hope to see each and every one of you in the near future. Until then, Arrivederci!

Eating like a Horse

2009-07-05T04:44:00.000-07:00

As our trip to Siena comes to a close, Arthur, Ankush, and I decided to partake in a final ritual of manhood: eating. Now we are no Joey Chestnut or Takeru Kobayashi, two men who just ate 60+ hot dogs at the Nathan's Hot Dog Eating Contest. We are not even Daniel Oyon, Santoh Reddy, or Yoav Karpenshif, who took down the powerful Matthew Weinschenk by eating a dozen Krispy Kremes. No, we were much gutsier. We three geniuses of gastronomia ate a one kilogram steak each. If you are trying to do the calculation in your head, 1 kilo is about 2.2 pounds and 2.2 pounds is about 35 ounces of pure meaty goodness. As Arthur and I said, that steak was “the best worst decision of our lives,” as are still digesting it. While we tried to cut through the three inches of mammal, with gallons of sweat streaming down our faces, I naturally thought about chemistry and how my stomach would break down eating the equivalent of a puppy. I was really thinking about it 24 hours later when I felt like a cow had overtaken my body. Thus, I would like to talk about the fine art of digesting protein, as we had enough protein for a family of five. (Just for your information, in 100 grams of a t-bone steak there is approximately 24 grams of protein. That means we ate about 240 grams. The recommended daily allowance of protein is about 50 grams. Eat your heart out Arnold Schwarzenegger.)
Digesting protein is really quite simple. Protein is made up of long amino acid chains that we know helps aid in muscle formation. The environment in the stomach is mostly made of pepsin, hydrochloric acid with a pH from 2-5. This acid is secreted by parietal cells at a pH of about 0.8, but after mixing with other stomach liquids it reaches a pH from 2-3. The long chains of protein are broken down into smaller chains by these strong acids as the food passes into your small intestine. Then, enzymes from the pancreas (such as trypsin and chymotrypsin) break down the proteins further. Now, the small amino chains are absorbed into the body.
Many enzymes are required in this process because each amino acid chain breaks down differently. If food is broken down appropriately and not eaten to excess (*cough* Arthur, Ankush and I) almost 100% of protein is made into individual amino acids.
I would like to end this last blog post, much like Imran, by thanking everyone involved in this trip. From the Unisi students and faculty, to Natalie, to our tremendous professors in Dr. Soria and Dr. Norton, to eighteen incredible kids, I have never had more fun or enjoyed living so much as on this trip. To the Unisi people, thanks for your warm hospitality, pleasing dinners, and accepting us as your own. To our professors, thank you for putting up with all of our loud mouths while still allowing us to have fun. Oh, and thanks for going to that ridiculous carnival with us. Finally, thanks to eighteen of the most intelligent, entertaining, and legendary kids at Emory University. I am glad to hold the record for the largest party at the Refugio: 10-15 people playing cards in the common room. The stories I have are uncountable and I look forward to telling them for years to come. Siena will never be the same.

p.s. Sameer does not eat pork.

References
http://tuberose.com/Digestion.html

http://www.netrition.com/rdi_page.html

http://www.highproteinfoods.net/beef-and-veal/1576

Caught in the Act: Art Forgery

2009-07-04T23:41:00.000-07:00

Art forgery has existed for thousands of years dating back to a time when ancient Roman sculptors produced fake copies of Greek sculptures. Yet, perhaps the most famous story of forgery occurred in the Renaissance, 1496 to be exact, and involved the great Michelangelo. At a young age, Michelangelo decided to test his skill by sculpting a sleeping cupid statue, burying it in the acidic earth, and passing it off as an antiquity. The artificially aged statue found its way into the hands of Cardinal Raffaello Riario of San Giorgi. Only after hearing of Michelangelo’s bragging did the Cardinal learn of the forgery and demand his money back. Nowadays, however, there are other ways to learn of a forgery than through counterfeiters’ boasting.

Through a talented team of art conservators and scientists, the authenticity of a painting can be determined in a variety of ways beyond the initial visual analysis. These include: carbon dating, X-ray radiographs, and X-ray diffraction. All of these techniques hinge on verifying the date of the painting by examining the materials that comprise the work of art. Carbon dating, a method that analyzes the ratio of carbon isotopes ¹²C and ¹⁴C, is useful in determining the age of materials less than 10,000 years. X-ray radiographs, on the other hand, help conservators see the creative process of the artist, revealing every layer of paint on the canvas. Sometimes a painting will appear to be an antique until radiographs reveal a typical 19^th-century painting underneath. Lastly, X-ray diffraction is used to understand the pigments in the painting. Conservators and art historians alike know the dates of when certain pigments were introduced into the art world. For example, if X-ray diffraction shows the usage of Prussian blue, an ink of the 18^th century, in a painting that claims to be of the 17^th century, it is a fraud.

Clearly it is important for paintings to be examined before being sold to museums and collectors for large sums. Carbon dating, X-ray radiographs and X-ray diffraction are only a few of the techniques utilized by scientists to verify a painting’s authenticity. And while the number and accuracy of the techniques used by conservators grow, the techniques of modern-day forgers are desperately trying to keep pace and trick us once again.

References:

http://www.history.com/encyclopedia.do?articleId=201568

http://www.museumofhoaxes.com/hoax/Hoaxipedia/Renaissance_Forgeries/

http://en.wikipedia.org/wiki/Art_forgery

The all powerful oxygen

2009-07-04T18:25:00.001-07:00

After much thought, I decided to write my last blog about a topic I thoroughly enjoyed researching for my second paper: atomic oxygen. A single atom of oxygen, atomic oxygen does not exist in Earth's atmosphere. In space, however, it is formed when the sun's UV rays split diatomic oxygen into a pair of free radical oxygen. This atom is destructive on its own because it has two unpaired electrons that are desperate to pair with other electrons.
Researchers at NASA accidentally discovered that atomic oxygen could be used to remove layers of organic material from a surface. This discovery created awareness that atomic oxygen could be used for removing organic contaminants or aged varnishes from the surface of paintings.
Remember how in the linseed oil article from class there was a reference made about how some lady kissed a painting of a tub, planting a big one near the bottom of the painting? The painting, "Bathtub," by Andy Warhol had to be restored using the atomic oxygen method since traditional solvent methods were unable to be utilized.
On a side note, worldwide an average of one collection or gallery suffers fire damage every day (estimated), and paintings damaged by charring are very resistant to traditional cleaning techniques. Current processes used to restore artwork generally use chemical solvents to remove dirt, varnish and thin layers of soot. With damage from heavy deposits of soot, or even charring or graffiti, these techniques are not effective. NASA found that atomic oxygen could remove layers of soot from charred paintings too. How? Because atomic oxygen will not react with inorganic oxides, such as most paint pigments, it could be used to restore paintings damaged by soot.

Below is a link portraying how atomic oxygen was used to restore the charred painting, Madonna of the Chair. The left photograph was taken after the Cleveland Museum of Art staff used acetone and methylene chloride to clean and restore the painting. The right half was taken after Glenn researchers used the atomic oxygen technique to clean the painting.
http://www.nasa.gov/images/content/67935main_atomicox_big.jpg

I just want to end this last post of mine by saying that I enjoyed my entire stay in Italy with 18 of the most interesting characters I have ever met, all of who I have grown to love in just a matter of a few weeks. Oh and Natalie, Daphne, and Jose, you guys aren't half bad either!!! Just playing, of course. Thank you, everyone (including Renzo, Gabriella, Daniela and the Italian students), for making this one of the most pleasant, exciting, and memorable experiences I have ever had! I hope to see everyone around during my final year of college at Emory! I love you guys!

Sources:

http://www.nasa.gov/vision/earth/everydaylife/AtomicOxRestoration.html

Dude, are you crying?

2009-07-04T06:32:00.000-07:00

As our journey here in Siena comes to an end, we say our goodbyes to new friends, wondering if we will ever see them again or come back to this beautiful city. After saying goodbye to some of our closest Italian friends, Angelo and Paolo, I started wondering if there was any chemistry behind the act of crying. Being a guy, of course I have never shed a tear in my life, except in the movie Click, which was an unbelievably sad movie. Though I could find little information about the emotional act of crying, I did come across why onions make people cry, which I also found interesting. After eating an entire onion for fun at one point in my life, I have been somewhat curious about this vegetable.
Everyone knows that cutting up onions will make your eyes burn a bit and tear up. When you cut an onion, you break cells, releasing their contents of amino acid sulfoxides. Enzymes mix with these acids to form propanethiol that float to your eyes. This reacts with the water in your eyes to form sulfuric acid; this irritates your eyes, causing your eyes to release tears to wash it away. Cooking onions inactivates the enzyme, so the smell of cooked onions do not burn your eyes. If your eyes really irritate you when you are trying to chop up onions, you can try refrigerating onions before cutting them, as the cooler temperature will slow down the reaction, or cutting the onion underwater.
Also, I had a great time in Siena with all of you. I wish nothing but the best for everyone’s future. If anyone wants to have a glass of wine with me back in the states, give me a ring and I’ll try my best to come, after all, I do like to party.

http://chemistry.about.com/od/chemistryfaqs/f/onionscry.htm

A chilling injury...

2009-07-04T02:35:00.000-07:00

As I was cleaning out our refrigerator this morning in the Refugio, I came across a long lost banana that I had left in there during the Brazil V. US game. Of course, the banana looked completely nasty, but since I had no other food... I ate it. And you know what? It was good. I mean gooood. So, I decided to look into banana peels and why they turn black and unappealing.

In 2007, there was a study done on how heat treatments effect the browning of banana peels, a.k.a. their chilling injury (or CI). Previous studies had shown that if treated in hot water before cold storage, other tropical fruits showed less ripening and browning, so, why not bananas too? The bananas were gathered at 80% maturity, which is the same maturity that we would buy in a grocery store. They were then placed in water at 42 degrees C for 5, 10, or 15 minutes, then stored at 4 degrees C. At various points during cold storage, samples from the peels were taken to observe any chemical or structural changes.

The results? The main reason for chilling injury is the amount of saturated versus unsaturated fatty acids in the peels. The control bananas (which were not treated with the hot water) showed an increase is saturated FAs and a decrease in unsaturated FAs. The heat treatments prevented the increase in saturated FAs while changing the decrease of unsaturated FAs to an increase in them. Basically, the better the ratio of saturated versus unsaturated fatty acids, the higher the peel's tolerance to cold temperatures. The heat treated bananas began browning four days later than those not treated, and after ten days, the heat treated bananas did not show maximum blackening, while the control bananas looked like the banana I found in our fridge.

So the moral of the story: if you want to store your bananas in the refrigerator without them becoming black and gross, you should try the hot water treatment, and let me know how it goes.

And for your entertainment, here is another experiment done with banana peels brought to you by Mythbusters.... http://www.youtube.com/watch?v=YZRq3XxCZXo

And for further reading on the experiment, here is the paper.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TBJ-4R5G84B-3&_user=7597297&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=947741236&_rerunOrigin=google&_acct=C000036918&_version=1&_urlVersion=0&_userid=7597297&md5=a8368c83c4f5118cb1c9be9b16d375fa

Sore muscles

2009-07-03T06:47:00.001-07:00

The weekend before last, several friends and I travelled to Cinque Terre, where we hiked through the trails connecting each of the five coastal towns. By the time we got back to Siena however, my legs were quite stiff and sore, just like the soreness one feels after a long run or a day at the gym. At any rate, within a day or two, my legs were back to normal. Just as I did at one time, some of you may be wondering why your muscles get sore after a tough workout.

Your cells obtain the energy needed to do work (i.e. hiking over a mountain) by breaking down glucose to produce ATP (adenosine triphosphate). This is typically done through an aerobic process in which glucose is broken down to pyruvate, which is then broken down further to carbon dioxide and water through the electron transport chain. This process is aerobic because oxygen is the final electron acceptor at the end of the electron transport chain, where it is converted to water. However, in times when large amounts of energy are required, such as weight lifting or sprinting, the amount of ATP needed is typically far greater than the amount of oxygen the lungs can provide.

When this happens, the body switches to an anaerobic process, in which oxygen is not used. Although this process does not produce nearly as much energy, it does produce enough to allow body functions to continue. As your breathing and heart rate increase, oxygen levels in muscle tissue eventually peak. When this happens, the electron transport chain function also peaks. However, because glucose is being broken down at a much faster rate, pyruvate eventually begins to build up inside the cell. This excess pyruvate is then diverted into an alternative pathway, through which it is converted to lactic acid. It is the presence of this lactic acid that leads to muscle soreness because it cannot be readily eliminated by the cell, unlike carbon dioxide and water.

When the body’s energy requirements subsequently drop, the anaerobic processes eventually stop. However, the muscle cells still require a minimal amount of energy to for normal daily function, and so all the pyruvate produced is once again pushed into the electron transport chain. In addition, all the lactic acid that has built up in the cells begins to be converted back to pyruvate, which then can also be sent to the electron transport chain. Consequently, within a day or two, all the lactic acid that has built up in the cells will have been converted back into pyruvate and all the muscle soreness will be gone.

Meth from Sudafed

2009-07-03T01:23:00.000-07:00

As I was taking a Sudafed pill this morning to clear up my sinuses, I was reminded of the presentations that were given regarding drugs and the brief discussion we had afterwards about the synthesis of methamphetamines. The structure of meth is this

And the structure of pseudoephedrine, the active ingrediant in Sudafed is this

Now one can see why we have to sign for buying Sudafed, and we are restricted to the amount we can buy at one time. Or rather, we are not restricted if we go to different stores, but the computer system will red flag us and send our information to some form of law enforcement. It would be easy to manipulate pseudoephedrine into methamphetamine just by reducing the alcohol group by various means (theoretically one way is to bubble hydrogen gas through a solution of pseudoephedrine and paladium or platinum pellets for catalysts).

So the hard part about making meth is not its synthesis. What really is the challenge is isolating pseudoephedrine from the Sudafed pill. The most amount of pseudoephedrine that can be found in a tablet s 240mg, enough for one "hit" of meth, though during the isolation process much meth can be lost if the "chemist" is not careful. If one pill has enough pseudoephedrine for a hit of meth, one may wonder why taking one of thses Sudafed pills doesn't give you the same effect. That alcohol group is enough to change the chemistry of the drug such that the two drugs will not have the same effects at the same doses. But that doesn't mean Sudafed itself cannot be misused as a recreational drug. Take enough of it and you can get F-ed up easily. Anywho, just thought I'd share what I had found on this subject.

Camouflage Chemistry/Biology

2009-07-01T10:04:00.000-07:00

After my presentation today, Anthony asked a very good question regarding the chemistry of camouflaging. It sparked my interest to look up the subject matter and write my final blog over it. I found a website that explained the science behind camouflaging very well, so I am just going to directly quote it.

'Chameleons change color by manipulating the chromatophores in their sub-dermal layer. Each chromatophore contains one pigment, and a sphincter muscle. When contracted, the pigment is squeezed up into a flat region above the chromatophore, showing that pigment. As you can imagine, this works much like an RGB display; an animal can have only a few pigments, and make many different colors by combining them selectively. Chameleons have four different layers to their skin, in order of increasing depth: the protective epidermis, the chromatophore layer (which contains red and yellow pigments), the melanophore layer which can display brown or black pigments or reflect blue, and the nether layer, which is white. Any given color morph of a species of chameleon only has a few different patterns and color combinations in its palette.

So say the chameleon is frightened by a Boomslang or a Shrike (both predators of chameleons), a combination of hormone action and nerve impulses will selectively expand and contract some chromatophores of the chameleon into either a camouflage pattern or a bright pattern which often means "I taste bad" or "I'm poisonous" in the animal world. These transitions can take as little as a few seconds, and a viewer will see a gradual shift from one color pattern to the other. '
http://everything2.com/node/1685107

HDLs and LDLs

2009-06-29T19:40:00.000-07:00

Last week, we visited Dr. Daniela Valensin’s lab, where we performed an NMR analysis on olive oil. Nuclear magnetic resonance is used to characterize the olive oil and can help evaluate its nutritional content. For example, NMR can be used to which saturated, monounsaturated, and polyunsaturated fats are present in olive oil. One particular item of interest that I learned on this trip, however, was that olive oil is considered to be a healthy alternative to vegetable oils because of its high levels of monounsaturated fats and minimal levels of trans-unsaturated fats. High levels of monounsaturated fats are good because they help lower LDL (bad) cholesterol levels and raise HDL (good) cholesterol levels.

Cholesterol and fatty acids are packaged into complexes known as lipoproteins with proteins by the liver in varying degrees of density, including chylomicrons (which are the least dense, largest, and contain the least protein) to LDLs (low density lipoproteins) which are slightly more dense than chylomicrons to HDLs (high density lipoproteins) which are the most dense and contain the highest levels of proteins. High levels of HDLs are good because the complexes carry proteins that aid in the absorption of cholesterol from cell membranes and transport back to the liver. Consequently, HDLs help lower blood cholesterol levels.

LDLs, on the other hand, function primarily to carry cholesterol to tissues. Excessive levels of cholesterol in cell membranes can be problematic because it increases the permeability of the membrane, possibly allowing unwanted, and perhaps harmful, materials to enter the cell. In addition, extremely high levels of LDLs in the bloodstream can promote a pathway through which LDLs are absorbed by the cell and oxidized, leading to the inflammatory response known as atherosclerosis. Conversely, HDLs can be potentially anti-inflammatory because they inhibit the oxidation of LDLs that leads to this atherosclerosis.

References: http://en.wikipedia.org/wiki/High_density_lipoprotein

The Candyman Can

2009-06-29T13:22:00.000-07:00

This week was our last week in class and in Siena. To conclude our analytical chemistry class, Stephanie and I did a presentation on the chemistry of chocolate blooms. Chocolate blooms occur when chocolate is stored at high temperatures or for a prolonged period of time (2-3 years). They are a direct result of the substance's natural fat, cocoa butter. When chocolate is tempered, manufacturers stabilize the cocoa butter in its Beta-5 form. This form, however, is not the most stable form: form 6 is. Therefore, when chocolate is exposed to high temperatures, there is a tendency of the liquid-like protons in the cocoa butter to leave the chocolate crystalline matrix and migrate to the surface. It is there that they recrystallize and form a whitish-grey film that is unappealing to consumers.

Several groups of scientists are currently studying ways to prevent the blooming of chocolate. NMR analysis has been used to determine that certain additives slow the process. The chemical structures of the triglycerides in cocoa butter have also been studied using powder x-ray diffraction. Though the research is still young, the teams are looking for a way to produce chocolate containing cocoa butter that is already in Beta-6 form, thereby decreasing the likelihood of fat blooms. More information can be found at the websites listed below.

I will be leaving Siena in the morning, so this will serve as my last blog post. I have thoroughly enjoyed my time here at the UNISI. The people I have met and the experiences I have had will truly impact my outlook on life for years to come. Thanks to Daniela, Renzo, Gabriela, and all of our other professors from UNISI for making our time here as enjoyable as possible. Ciao ragazzi!

www.physorg.com/news1208.html
www.esrf.eu/UsersAndScience/Publications/Highlights/2004/SCM/SCM8

Cannabis Controversy

2009-06-29T08:18:00.000-07:00

When I went to Amsterdam a couple of days ago, I observed that the use of cannabis was common and tolerated. My first question was that how could the population of a whole country use this ’drug’ and still maintain its efficiency and production? In fact, the country has a top ten per capita GDP. This made me curious about the use of cannabis and whether or not it should really be classified as a true drug.

First of all, I am not condoning marijuana use in any way. There is a reason why it is illegal in many countries around the world and this is probably because of the psychoactive substance in the plant called THC. Tetrahydrocannabinol produces the high associated with cannabis and has been known to alter brain function (like short-term memory loss). However, a drug is something that can be abused and can alter body functions. One can classify coffee or many over the counter medicines as drugs but their legality is never disputed. There have never been any reported fatalities linked to the overdose of cannabis and one study reports that 1500 lbs of pot would have to be smoked in 15 minutes to die from its toxicity. Frankly, I think that is impossible (well, maybe not).

There is a strong argument for the tolerance of cannabis. The plant is used for many medicinal purposes like for the treatment of nausea, pain, and chronic illness. In fact, there has been some research performed that showed some extraordinary benefits for patients with cancer and AIDS who are given cannabis. THC also provided positive benefits for patients suffering from glaucoma, multiple sclerosis, Alzheimer’s disease, Tourette’s syndrome, Parkinson’s disease, ADHD, and depression. In fact, some studies were able to confirm that THC can even promote neurogenesis and neuroprotection (the production and protection of neurons in the brain). Another study confirmed that THC can prevent some types of oxidative damage from free radicals and may be even more effective than some antioxidants.

There are many issues and benefits of marijuana that I haven’t included in my brief blog. I just wanted to bring attention to the fact that we should not pass judgment on cannabis when its true effects are unknown. More research needs to be done to confirm the health effects of cannabis. Only then can we discuss whether or not it should be legal. Until then, I encourage people to go to Amsterdam and see the cannabis phenomenon for themselves. But be careful…if you try it you might suffer from some severe health benefits!

References: wikipedia.org

Gazing into the eye of a fly

2009-06-29T07:56:00.000-07:00

In this week's lab we stared right into a fly's eye.

In Dr. Baldari’s lab, they use a Scanning Electron Microscope (SEM) to analyze many of the biological specimens that they work with. The SEM is the next generation of microscopes because it uses a beam of electrons instead of light to form an image.
The SEM has allowed researchers to develop new areas of study in the medical and physical science fields.

It has many advantages over traditional light microscopes. It has a greater area of vision which allows the researcher to look at more of a specimen at a time. It allows higher resolutions and since the SEM uses electromagnets instead of lenses to focus the beam it gives the researcher greater degree of control in the magnification.

The SEM is an instrument that produces a large magnified image by using electrons instead of light to form an image. A beam of electrons is produced at the top of the microscope by an electron gun. The electron beam follows a vertical path through the microscope, which is held within a vacuum. The beam travels through electromagnetic fields and lenses, which focus the beam down toward the sample. Once the beam hits the sample, electrons and X-rays are ejected from the sample. Below is an image of the entire microscope.

Detectors collect these X-rays, backscattered electrons, and secondary electrons and convert them into a signal that is sent to a screen similar to a television screen. This produces the final image. Since the detectors are able to collect electrons from every direction, this allows the researcher to get a comprehensive 3-D image of the specimen.

Your Inevitable Doom

2009-06-29T07:55:00.000-07:00

Friday's discussion on Napoleon Bonaparte's mysterious death, possibly due to deathly wallpaper (arsenic poisoning), greatly interested me. After the class discussion, I decided to further look into the history and science behind arsenic poisoning. Arsenic ranks 12th in line for the amount of elements in the human body. Arsenic is found in a wide variety of products such as glass wallpaper, seafood, and vegetables. Studies have shown that inorganic arsenic is more toxic than organic arsenic.

Arsenic has appeared throughout history beginning with the Arab alchemist Jabir who in the 8th century created a poison called arsenic trioxide. Arsenic trioxide is odorless, colorless, and leaves no traces in the body. On the other hand, the Joseon Dynasty in Korea used arsenic-sulfur to poison important political figures as a sort of capital punishment. Accused political figures had to drink a cocktail containing arsenic-sulfur called sayak. During Europe's Middle Ages, Elizabeth Bàthory (Hungarian countess) is believed to have used arsenic to poison her lovers. The poison was suppose to keep her lovers from leaving her. To be honest, I do not understand how killing her lovers is not the same concept as the lovers abandoning her. Furthermore, women in the Victorian era used a special powder to whiten their skin; the powder consisted of chalk, vinegar, and arsenic. The joke is that the powder only prevented aging through the absorption of arsenic into the bloodstream which then led to the user's death. In the art world, arsenic was present in an Emerald Green pigment used by impressionists. Rumor has it that Van Gogh's neurological symptoms could be due to his use of Emerald Green.

During the 19th century, the press provided circumstantial evidence on the possibility of mass poisoning in Europe. The large controversy over Arsenic poisoning had arisen from Karl Scheele's first synthesis of arsenic greens in 1778. This discovery led to the use of arsenic greens in wallpaper. By 1863, the United Kingdom produced 500-700 tonnes of arsenic green. German chemist Gmelin along with Italian chemist Gosi discovered that in damp environments, inorganic arsenic is transformed into a gas known as trimethylarsine. At this time, children were the number one victims of arsenic gas poisoning due to the green wallpaper used to decorate their rooms.

The lesson to learn here is that everything in life can lead to your death and/or recovery. All you need to do is sit back and relax. As one individual brilliantly said: “you have to die from something” (I do not remember the exact quote). Haha!

References
emedicine. Toxicity, Arsenic. http://emedicine.medscape.com/article/812953-overview (accessed
June 29, 2009).
Inventor Spot. Arsenic: Is This Ancient Poison a Modern Remedy? http://inventorspot.com/articles/
arsenic_ancient_poison_modern_remedy_24090 (accessed June 29, 2009).
Popular Science. Killer Wallpaper. http://www.popularscience.co.uk/features/feat17.htm (accessed
June 29, 2009).

NMR analysis in depth

2009-06-28T18:40:00.000-07:00

We visited the uniersity of Siena the last Monday and Daniela explained us in detail how an NMR spectrometer works and its utility to determine the quality of the olive oil. The olive oil is categorized according to its acidity. The main acid present in olive oil is oleic acid. Oleic acid is a monounsaturated fatty acid and its content is also very high in the human adipose tissue. The quality of the oils goes from extra-virgin olive oil with less than 0.8% of acid to Lampate oil that is not recommended for cooking puposes due to its high acidity. We also saw the NMR machine and learned about all its components. We had to take off our watches and anything containing metal before due to the strong magnetic field surronding the NMR. It was a wonderful experience, we always have studied NMR and learned very well how to determine compunds looking at the NMR spectrum but I have never seen the actual machine before. What called my atention was the fact that the sample had to be in liquid state to be analyzed. The university of Siena does not possess the equipment for solid-state NMR, but Emory University does, one more motive to be proud of.

All of the analytical techniques have its limitations and its advantages. Liquid or solution-state NMR requires that the sample be soluble at some concentrations but when the analyte´s molecules weight passes the 30kDa the techniques becomes very complicated. There is a size limitation for this NMR technique. Solid NMR does not require the sample to be in solution, liquid state or any different structure, this allows for much more efficient and direct analysis. Solid NMR permits to analyze samples bigger than 100kD. Solid NMR, as every technique, also has disadvantages when compared to solution-state NMR. The main difference between the two techniques is the random motion, mobility and rotation of the sample in the liquid state. Solids lack these rotational and translational movements even though some molecules can still have some sort of rotation and movement, like the rotation of the methyl groups or the flip of the rings.

The advantage of solid NMR is that since the molecule are mainly fixed in the space, clear and defined lines appear in the NMR Spectrum. The disadvantage is that information regarding the orientation of the molecule in the space is not avaliable. This disadvantage somehow limits the analysis of biological macromolecules.
In Solid-state NMR anisotropic nucelar interactions (directionally dependent interactions) influence the behavior of the system, of the nuclear spins. There are two anisotropic interactions characteristic in solid NMR: chemical shift anisotropy and internuclear dipolar coupling.

Microscopes Should be Sold on eBay

2009-06-28T16:39:00.001-07:00

Expecting to only perform a western blot in Dr. Baldari's lab on Tuesday, I was surprised when one of the undergraduate students took us to observe the various microscopes. The microscopes were kept in the basement to minimize vibrations from the building and the environment. I was shocked when I heard the purchase price of the microscopes. I'm talking about $500,000! One of the microscopes that particularly interested me was the Transmission Electron Microscope (TEM). TEM can magnify objects up to 600,000x! Unlike the light microscope, TEM uses monochromatic (light from a single wavelength) electrons instead of light to magnify objects. Electrons are emitted into a vacuum until they reach electromagnetic lenses. These lenses focus the electrons into a thin beam that reflects and transmits through the specimen. The electrons that transmit through the specimen hit a florescent screen. The image that appears contains different shades of color depending on the density of the specimen. The darker areas of the image represent fewer electrons transmitted through the specimen.

TEM can be used to analyze a variety of sample including samples from medical and biological sciences. For example, TEM can be used to observe the morphological changes of human tissues when treated with drugs. Tissue samples have to be cut into extremely thin sections to be viewed by this microscope. The size requirement for TEM is actually an advantage for researchers who have difficulty obtaining samples in the first place.

References
Intertek Northwest Technology Centre. GLP Tissue Microscopy. http://www.intertek-cb.com/ nwtc/biotemlab.shtml (accessed June 28, 2009).
Nobel Prize in Physics. The Transmission Electron Microscope. http://nobelprize.org/educational_ games/physics/microscopes/tem/index.html (accessed June 28, 2009).
University of Nebraska. Transmission Electron Microscope (TEM). http://www.unl.edu/CMRAcfem /temoptic.htm (accessed June 28, 2009).