Category Archives: chemistry in everyday life
How are drugs designed? Come on Friday 2nd May at 18:00 at the Athens Science Festival, Technopolis Gkazi to listen to my talk! See the detailed program of the festival here.
This talk will address how drugs are designed to combat a disease – from the discovery of the cause of the disease (e.g. a mutant protein), specialized techniques for the design of small chemical molecules (that are drugs), to clinical trials. We will also discuss advances and progresses in individualized treatment (also known as personalized medicine), i.e. how DNA testing could help each patient receive medication specifically tailored for them.
Πώς σχεδιάζονται τα φάρμακα; Ελάτε την Παρασκευή 2 Μαϊου στις 18:00 στο Athens Science Festival, Τεχνοπολις Γκάζι, να ακούσετε την ομιλία μου.
Η ομιλία έχει θέμα το πώς επιτελείται ο σχεδιασμός φαρμάκων για μία ασθένεια – από την ανακάλυψη του αιτίου που προκαλεί την ασθένεια (π.χ. μια μεταλλαγμένη πρωτεΐνη), εξειδικευμένες τεχνικές για το σχεδιασμό μικρών χημικών μορίων που αποτελούν τα φάρμακα, μεχρι και τις κλινικές δοκιμές. Επίσης θα συζητήσουμε τις προοπτικές και εξελίξεις στην εξατομικευμένη θεραπεία, το πώς δηλαδή με εξέταση DNA μπορεί ο κάθε ασθενής να λαμβάνει ένα φάρμακο που είναι ειδικά κατάλληλο για εκείνον.
Περισσότερες πληροφορίες και μία μικρή περίληψη για το θέμα θα βρείτε σε πρόσφατο άρθρο στην ιστοσελίδα της διοργάνωσης.
Love at first sight? Desire in a bottle? There have been a lot of claims about what pheromones can do, but what is the science? Dr. George Preti and Dr. Charles J. Wysocki of the Monell Chemical Senses Center discuss the chemistry of pheromones and how mood and emotion can be communicated through chemical signals.
Kalydeco, a drug for cystic fibrosis, is the most important new drug of 2012 according to Forbes magazine and was developed by Vertex pharmaceuticals with seed funding from the Cystic Fibrosis Foundation.
Cystic Fibrosis is a genetic disorder that results in scarring (fibrosis) and cyst formation within the pancreas, lungs, liver, and intestines.
Kalydeco, given alone, will only help a few thousand patients the world over. Like other drugs for very rare diseases, its price is very high: $294,000 per patient per year.
Though its chemical structure could be routinely made by a synthetic chemist, it is covered by a patent so it is illegal to make in a lab.
The efforts to cure cystic fibrosis were spearheaded by a discovery from Francis Collins, later famous for heading the Human Genome Project and then the National Institutes of Health, who discovered the gene that, when mutated, causes cystic fibrosis 23 years ago. Kalydeco is the first drug to directly affect the defects caused by these mutations, leading to improvements in patients’ lung function.
Europium(III) oxide, alongside other chemicals, is phosphorescent and is used in the anti-counterfeiting details in Euro banknotes.
Most of the trivalent rare earth elements are luminescent. This means that they can be excited by shining a light of a particular wavelength at them. When the ions relax again, they emit light – of a different wavelength. That is luminescence.
Euro notes luminesce in the red, green and blue (excited by 254 nm). The red light is clearly linked to europium and most likely to a Eu3+-β-diketone complex.
The magazine, which appears four times a year, contains articles that feature real-world applications of chemistry concepts introduced in the classroom. Latest issues cover themes such as the application of nanotechnology, great discoveries in chemistry, and the science behind weather folklore.
The site provides a Teacher’s guide, videos, material for the classroom and more.
Check out the ChemMatters web site for the latest issue!
View the lastest Episode on ChemMatters: “Episode 10: Graphene: The Next Wonder Material?” on carbon allotropes and the applications of graphene.
Tennis has grown to be my favorite sport, so I found this great YouTube video of Dr. Ainissa Ramirez from Yale University explaining the science behind tennis:
Basically, modern rackets are high tech composits of carbon fibers embedded in epoxy (glue), which give them high strength and low weight. The most expensive strings are made of cow gut, but most commonly nylon is used, which is a flexible polymer.
- Nylon, a synthetic polymer used for tennis racket strings.
Strings hit the ball and create topspin, which makes the ball fall sooner than a ball without top spin. This effect is called the “Magnus effect“. This is what happens to a ball with topspin: while the ball is rotaitng, a thin layer or air around it is also rotating with it. That means that the velocity of air below it is faster than the velocity of air above it, causing it to fall sooner on the ground. That’s why you have to use top spin with your balls if you want to be too fast for your opponent.
Venus Williams usually hits a 1,200 rpm ball and Rafa Nadal 3,600 rpms. That’s faster than a revolving washing machine:-)
After reading some tennis science, I hope you agree that knowing a little bit about the chemistry and physics of tennis can really improve you as a player…! 🙂
What Is Alcohol?
When you mention “alcohol”, you most certainly mean “ethanol”, a simple chemical which is created when grains, fruits, or vegetables are fermented. Fermentation is a process that takes place when yeast (fungi) convert food sugars into ethanol and carbon dioxide.
Sugar + yeast —> alcohol + carbon dioxide
C6H12O6 + yeast ——> CH3CH2OH + CO2
- Alcohol travels to your stomach.
- From the stomach, it is quickly passed into the bloodstream, where it travels in a few minutes to every part of the body, including your brain.
- In the brain alcohol affects your neurons: It alters neuron’s membranes and ion channels, enzymes such as acetylcholine, serotonin, and GABA receptors.
- When alcohol binds to these enzymes, it slows the function of the central nervous system and that’s why you feel more relaxed and stress-free.
- Ethanol also inhibits the production of a hormone (ADH) that regulates urine flow, causing increased urine production and dehydration.
- Alcohol increases dopamine by stopping enzymes that degrade it – that’s why you feel happier!
- Ethanol also causes blood vessels to dilate, resulting in flushing of the skin and a sensation of warmth as blood moves into capillaries.
- If you’ve had a large meal, alcohol will stay longer in your stomach, that’s why you can’t get drunk as easily. But eventually, it will enter the bloodstream and do its tricks:)
Your body sees alcohol as an intruder and tries to get rid of it using an enzyme to break it down, “alcohol dehydrogenase“. On contact, the enzyme snatches a hydrogen atom off the ethanol molecules in your drink, rendering it into non-intoxicating acetaldehyde, which is associated with hangovers. Alcohol dehydrogenase is less efficient in Asian populations. Lungs and liver also remove 10% of the alcohol in your body by urine and breath.
- Fuel: The largest single use of ethanol is as a motor fuel, fuel additive, and as a rocket fuel. Over 20% of cars in Brazil are able to run on 100% ethanol fuel.
- Raw material: Ethanol is an important industrial ingredient and has widespread use as a base chemical for other organic compounds, such as ethyl halides, ethyl esters, diethyl ether, acetic acid.
- Solvent: Ethanol is miscible with water and is a good general purpose solvent. It is found in paints, tinctures, markers, and personal care products such as perfumes and deodorants.
- Preservative: for biological specimens.
- Antiseptic: Ethanol is used in antiseptic and some antibacterial soaps and wipes. Ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria and fungi, and many viruses, but is ineffective against bacterial spores.
- Solvent: As a good solvent, you will find ethanol frequently used in many medicine, such as cough syrups.
- Drug: For therapeutic neurolysis: It is injected proximate to nerve tissues and into spinal subarachnoid spaces to produce degeneration of nerve function (neurolysis) for control of chronic pain.
A pathologist told a coroner’s court in north London that alcohol toxicity was the cause of the 27-year-old’s death, with her blood-alcohol levels measured at more than five times the legal limit for driving.
The report said that Amy’s blood alcohol content was 416 mg per decilitre at the time of her death. That’s 0.416% alcohol in the blood and about 9 drinks for a woman 45 kg like Amy. When large amounts of alcohol are consumed in a short period of time, alcohol poisoning can occur. Above a blood alcohol concentration of 0.5%, alcohol depresses nerves that control involuntary actions such as breathing and cardiovascular regulation. Moreover, it can cause hypothermia (low body temperature), hypoglycemia (too little blood sugar) and sever dehydration. These effects can lead to cause seizures, permanent brain damage, and ultimately death. That’s why you should never underestimate the effects of alcohol. And think twice before sipping more than three drinks in a row! Better to be safe than sorry.
Apparently it’s National Coffee Day today, read below to learn in less than a page how coffee gets decaffeinated – not an easy task!
Coffee contains over 400 chemicals important to the taste and aroma of the final drink: it is therefore challenging to remove only caffeine while leaving the other chemicals at their original concentrations.
To get rid of the caffeine, unroasted (green) beans are at first steamed. The beans are then rinsed with a “solvent” chemical that extracts the caffeine while leaving the other essential chemicals in the coffee beans. The process is repeated anywhere from 8 to 12 times until caffeine is removed in 97%-99.9%. So what is this magic “solvent” chemical. which is able to selectively remove caffeine while preserving the coffee aroma?
This solvent is nothing else but carbon dioxide (CO2), which is also found in our very own atmosphere. However, as you might have guessed, CO2 is not used for decaffeination as a gas from the atmosphere. For the decaffeination process, the coffee beans are soaked in a special form of CO2 called “supercritical” CO2. OK, so now you naturally have to ask what the heck is this “supercritical” CO2??
Every substance (water, hydrogen, oxygen, etc) has a so-called “critical point”. The critical point is the point above which, the distinction between liquid and gas phases of that substance stops being meaningful. That is you cannot tell any more whether this substance is gas or liquid. This new “phase”, being neither gas or liquid is called “supercritical”. A “supercritical fluid” can effuse through solids like a gas, and dissolve materials like a liquid.
So how does supercritical CO2 look like?
To achieve the supercritical state for most substances requires extreme temperatures and pressures. Carbon dioxide, however, has a fairly accessible critical point at ~ 31.1°C and 73 atm (our atmosphere has 1 atm). And it seems that supercritical CO2 has unique properties such that it can selectively extract caffeine from coffee beans, producing decaf coffee.
Carbon dioxide pressure-temperature phase diagram. The critical point is found at T=31.1°C and 73 atm. Above the critical point, one cannot really tell whether CO2 is liquid or gas. This new phase is called “supercritical”.
This is a question that I got very often during the summer. A sunblock can have two types of active ingredients: organic and inorganic chemicals, which reflect or scatter the light away so that it doesn’t reach the skin at all. The most common ingredients of a sunblock are zinc oxide or titanium oxide. You can usually tell who is using a sunblock just by looking, because the sunblock whites out the skin. Sort of.. like this:
Titanium dioxide (TiO2) is a white powder that has strong UV light absorbing capabilities. This property enhances TiO2 stability and enables it to protect the skin from ultraviolet light. Sunscreens designed for infants or people with sensitive skin are often based on titanium dioxide, as these mineral UV blockers are believed to cause less skin irritation than other UV absorbing chemicals. The titanium dioxide particles used in sunscreens have to be coated with silica or alumina, because titanium dioxide creates radicals in the photocatalytic reaction. These radicals are carcinogenic, and could damage the skin.
In newer formulations of sunscreens, TiO2 is combined with oil and is made up from smaller TiO2 particles (sized 40-50nm called nanoparticles). The oil in a sunscreen formula helps wet TiO2 and gives the optical effect of transparency so that you don’t have to look like someone’s painted you white.
For those who are wondering about the organic ingredients, these work primarily by absorbing UV light and dissipating it as heat. One of the most common organic molecules used in sunscreens is para-aminobenzoic acid, also know as PABA. The mechanism which allows PABA to absorb UV radiation is due to the resonance of the molecule. Resonance can be explained by saying that many molecules have more than one possible way in which the valence electrons could be placed. These electrons move freely across many nuclei. In PABA, a carbonyl group, a functional group where a carbon is double bonded to oxygen, can produce resonance by moving the valence electrons. The shift or movement of the electrons closely matches the frequency of UVB light, absorbing the light energy and releasing it as heat and or longer wavelengths of light. Source: http://www.sas.upenn.edu/~rosema/sunscreenchemistry.html
What Sunscreens/Sunblocks Screen
The portion of the sunlight that is filtered or blocked is ultraviolet radiation. There are three regions of ultraviolet light.
- UV-A penetrates deeply into the skin and can lead to DNA damage and premature skin aging.
- UV-B is involved in tanning and burning of your skin.
- UV-C, the most dangerous radiation is almost completely absorbed by the ozone in the atmosphere.
Sun is good for you, too
Although the sun can cause many aliments, UV rays are extremely important to a healthy functioning body. Vitamin D, which can not be produced by the body, is synthesized by the photolysis of a steroid in the deep epidermis of the skin. Without the exposure to natural light, the biochemical mechanism will not pursue causing disorders in both children and adults including rickets, ostomalaica, and osteoporosis.
For more info check this link.