Wednesday, 27 July 2011

Why is my beer flat???

Germans: good for cars, fabulous beer and great expressions like Doppelgänger

I love a good beer.  On a hot day there is nothing like a good beer.  In Finland the Finnish beer is strange and most of the time you never get any head.  Part of it is from the lack of good bartenders and also possibly the difference in beer compared to Guinees or Kilkenny.

The head on a pint of beer is primarily stabilized by adsorbed proteins and polypeptides derived from proteins in the malt. Lipid transfer protein 1 originating from barley stands out as the most important component relevant for the formation of foam. In malt, LTP1 is present in a foam inactive folded form. During the wort boiling LTP1 loses its 3D structure. The denaturated unfolded form is surface active (REF). The ethanol (usually around 5%) in beer helps the foam to form because it lowers surface tension of the liquid from 72 dynes to around 40 dynes, producing smaller gas bubbles caused by carbon dioxide (or in Guinness's case nitrogen).  The bubbles rise to the top of the glass forming a nice foam.  A well poured beer with the right composition the foam should go directly to to the bottom.  The foam prevents the carbon dioxide from escaping the liquid. The mouthfeel and the creamy sensation of the beer is preserved which is why Germans use steins.

If you do not see so much foam on the beer it may be caused by a couple of different reasons.  Firstly the beer could be completely flat lacking carbon dioxide .  If the beer is sitting there a while it goes flat.  However, the beer might also lack foam if the glass is dirty.   If they cleaned it with soap the surfactants from the soap can leave a trace residue on the inside of the glass.  Actually any residue soap, detergent, grease and wax can kill foam formation and retention actually attack the foam on a head of beer.  You might see the bubbles coalescing at the dirty spot and bursting (much like the roughness of the mentos in the previous repost).  If the surfactants from the soap attach to the surface on the bubbles the surface tension on the bubbles is lowered too much and they will burst.  Thus the foamy head disappears leaving the beer looking and tasting "flat". For these reasons, do not use regular liquid household dish washing detergents for glassware. They are fat-based and will leave a slight oily film on the glass. This causes beer to go flat quickly. Use a detergent designed specifically for beer glass cleaning. It must be low-suds, odor-free and non-fat. After washing, thoroughly rinse beer glasses and, if possible, air-dry them.  In Helsinki there are a few Czech bars that only clean the glass with cold water.  These bars usually pour the beer really well.

P.S. The other day I heard that 'Einstein invented the foam on beer.'  I questioned this because I think it is bull.  Beer was invented long before Einstein and it is pretty pure due to 1516 purity laws in Germany which made it so there were only a couple of ingredients in beer.  So no added ingredients.

P.S.S. Yesterday I reposted something from another blogger on the mentos.  It was mentioned briefly what might happen when you add a surfactant or grease to the solution.  If you add soap to coke it will kill all the fizz so the physical reaction will not happen.

Tuesday, 26 July 2011

Soda fountain science explained

As the author suggested : possibly some surfactant on the surface of the mentos could stop the reaction from taking place.....

Soda fountain science explained

Monday, 25 July 2011

It's All Gone Pete Tong

What would you do if you were deaf?  With ipods, walkmans, concerts, and every other loud noise destroying our ears this is a question that people should think about more and more.  Last night I watched the movie, 'Its all gone Pete Tong.'  I have watched this movie about five times.   It is great because it has craziness, music, tragedy and has the main character overcome his obstacles.  In the movie this DJ Frankie Wilde (spoiler alert) is the best DJ on Ibiza.  He is stupid, superficial and constantly partying.  The loud noise from the sitting in front of speakers combined with the drugs and alcohol causes him to go deaf.  It is impossible to fix hearing loss like many other ailments in today.  Although some preventatives measures like swallowing 1.2 g of N-acetylcysteine twelve hours before being bombarded with noise (recommended by Researcher Richard D. Kopke, MD), taking magnesium daily which helps stimulate blood flow, taking a break from the noise (something Frankie did way too late), picking the right earphones and carrying ear plugs for concerts.  Still to fix the problem as big as the holes in Frankie's ears is being worked on by some of my colleagues in the nanoear project.

What allows us to hear?  The eardrum of an ear simplifies incoming air pressure waves to a single channel of amplitude. In the inner ear, the distribution of vibrations along the length of the basilar membrane is detected by hair cells. The location and intensity of vibrations in the basilar membrane is transmitted to the brain through the auditory nerve.  The basilar membrane within the cochlea of the inner ear is a stiff structural element (taken from Wiki).  Its stiffness is important to hearing.  It is reported to have a stiffness of around 0.7 and 3.3 mN/m (REF) .   Loss of its stiffness as well loss of the hair cells can cause hearing loss like in Frankie's case.  These mechanical changes at the cellular level are involved in noise-induced hearing loss. There is a recovery of the cellular stiffness and cell length over a two-week period, indicating an activation of cellular repair mechanisms for restoring the auditory function following noise trauma (REF).  The loud noise generates free radicals that damage the proteins and lipids in those cells (which is why the N-acetylcysteine and other drugs may help prevent this).

At the end of the film Frankie discovers that the surface tension and wave propagation of sound can travel not just to the ear but to other parts of the body as well.  The skin's surface tension through his feet, and hands can be sensed in a similar way as in the ear allowing Frankie to apply the fader at exactly the right point to make the crowd go #&/%"/ crazy.

Thursday, 14 July 2011

Membrane proteins

Those proteins embedded in cell membranes make are difficult to study.  A Nobel Prize was given to the first membrane proteins that were crystallized.  So understanding membrane proteins are very important.  You can think of these membrane proteins as being a door and its frame and the walls being the cell membrane holding that door in plane and helping it with its function.  If the membrane is distorted (possibly due to anesthetics, lipid molecules or surfactants) like a warped wall it might stop the door from its primary function of opening and closing.  Biologists, biochemists and biophysicists are always trying to remove the doors from the walls so we can study them.  However, we want to study the door intact with all its hinges, door knob ect. not broken.  How do people do this?

Scientists use some kind of surfactant to first surround the membrane proteins, and extract them.  Many times these membrane proteins are not functional once they are extracted.  In the recent article by Matar-Merheb states that the 'underlying reason is the fact that detergents do not stabilize membrane domains as efficiently as natural lipids in membranes, often leading to a partial to complete loss of activity/stability during protein extraction and purification and preventing crystallization in an active conformation.'  When you cannot find good surfactants to extract proteins you do the next best thing.  You make them.  These French groups in this paper did just that.  They made 'anionic calix arene based detergents (C4Cn, n = 1–12)  designed to structure the membrane domains through hydrophobic interactions and a network of salt bridges with the basic residues.'  They reported that these molecules behave as surfactants and as measured using a Kibron Mictrough xl 'measured from the plots as the intersection between the plateau reached at the minimal value of the surface tension and the tangent of each curve' they obtained 'CMC values varying from 1.5 mM for C4C3 to 0.05 mM for C4C12.'  They found that these surfactants could extract membrane proteins from different origins behaving as mild detergents, leading to partial extraction in some cases. They also retain protein functionality, as shown for BmrA and maintain this protein's ATPase activity. 

It would be interesting to see how many other proteins these surfactants work with.  Maybe you will see BmrA and other membrane proteins in this database built for protein membrane interactions.

Wednesday, 13 July 2011

Aquaman's not so Sucky Superhero Surfactants

As I mentioned before I am a total nerd.  Growing up I bought comic books.  I never bought an Aquaman comic book though.  He was always deemed the lamest superhero.  After writing this blog and reading 20,000 Leagues I think that Aquaman has some merits as a superhero.  I stumbled onto a couple of years ago the Physics of Superheroes by Prof. James Kakalios and I would like to contribute something extra to his writing.

James Kakalios mentions that we all breath water.  We start by breathing air through our nose or mouth down our bronchial tube warming and moistening the air before it goes into our lungs.  The lungs are unbelievable.  It has a huge membrane surface area.  I still cannot imagine why people smoke.  If they knew how great the lungs are.  The air needs to be premoistoned before it goes into the lungs.  Why? 'In fact he air has to be at 100 percent relative humidity as it moves down the ever more finely branched tubes on its way to the alveoli' Kokolios states. 

The alveoli are small little spherical buds where exchange of oxygen and carbon dioxide occurs. These pockets are roughly 0.1 to 0.3 mm in diameter and have a large membrane surface area, they are smaller than the period at the end of this sentence. Capillaries located on the other side of the alveolar bud are narrow blood vessels that drop off a payload of carbon dioxide and pick up some oxygen before going to the heart.  The membrane surface area has to be large so the alveolar spheres have to be small and the capillaries have to be narrow.  This maximizes the ratio of surface area to volume so more regions for gas exchange to occur.

A transition between the gas molecules between the interior of the alveoli from the brochial tubes to the capillaries needs to take place.  The transition of these gas molecules needs a thin coating of water on the interior of the alveolar surface.  The water layer facilitates the transfer of gases.  Without it the inner cell walls of the alveoli would become dried out by contacting the air directly.  When it is dissolved from the gas phase an oxygen molecule can be transferred into the liquid phase allowing the oxygen to get picked up by the hemoglobin chromophores in red blood cells.  Thus the alveoli are considered to be air bubbles in water and we could not breath without a little water interacting on the surface of these air bubbles.  Aquaman, as well as that of Marvel Comics Prince Namor, the Sub-Mariner, and all the other denizens of comic books’ have the interesting ability to extract oxygen directly underwater.  Aquaman, and the others lack fish gills so he must have some sort of super power adaptation to allow him to continue breathing even when completely underwater and potentially with a significant amount of pressure exerted on his body.
However, unlike Aquaman when normal humans fill the lungs with water it can cause asphyxiation.  The surface tension of the outside water is sufficient to cause the alveolar buds to close up preventing oxygen into the blood stream.

As James Kakalios' suggests that pulmonary surfactants in Aquaman's lungs and also have very strong lungs to withstand the increased force to breath the denser water could help him to breath.  Pulmonary surfactants is a surface-active lipoprotein complex (with lipids and proteins) that has dipalmitoylphosphotidylcholine that has its tails facing the air.  The pulmonary surfactants' lipids face the air reducing the surface tension.  Aquaman then must have some adaptation to allow him to reduce the surface tension of water easier allowing him to extract air bubbles.  He might also have some adaptation with his hemoglobin (or myoglobin) that allows him to pick up the transferred oxygen better.

When writing this I was wondering if there was something out there that could make us into Aquaman.  My colleague told me about a rat that could be under water that he saw on television.  I looked up how this is possible.  It was from the James Cameron movie The Abyss.  (a clip is below).  This diving suit for liquid breathing uses highly oxygenated perfluorocarbons to dissolve into the blood through the alveoli.  These perfluorocarbons are very good surfactants (like teflon) that can go through lung tissue into the blood.   Perfluorochemical (perfluorocarbon) molecules and depending on their structures may impart different physical properties such as respiratory gas solubility, density, viscosity, vapor pressure and lipid solubility.  So this technology could be used for medical uses, deep sea diving, and space travel by modifying the structure and the delivery.  However, obstacles still need to be overcome.  Firstly some sort of gas exchanger has to be used to replenish the oxygenated perfluorocarbons.  So this is slightly different as Aquaman directly uses the water to get oxygen.   Secondly since the liquid is more dense and we would require more CO2 to be removed from the blood we would need some sort of attached ventilator as well as lungs as strong as Aquaman's.  So in the end Aquaman is not so crappy after all since we still do not have the technology to effectively breath under water to fight crime.

Thursday, 7 July 2011

Physiochemical Properties of Bowling

Bowling has just reached a new level in my brain. 

Podcasts are great.  They are like radio except without commercials, the people doing them (do you call them podcasters?) can say whatever they want, and the it has a great target audience.  Since I am a nerd I have been listening to Chris Hardwick, Jonah Ray and Matt Myra for the past six months on the Nerdist Podcast.  The word 'listening' might not do this podcast justice.  'Savagely addicted' might be better however.  So after a couple of weeks of throwing my addiction out the window I came back to the habit and like heroin I instantly got my fix with GeekDad.

Near the end of the hour long podcast they started talking about family and what GeekDad a.k.a. Ken Denmead does with his kids is pretty nerdy (depending on what you like to call it nerdy or geeky) like Dungeons and Dragons and possibly reading the Hobbit in voices.  All cool.  One thing where I became interested in was when GeekDad talked about bowling.  Chris Hardwick immediately became interested since his father was was professional bowler (see awesome video below about Billy Hardwick).  At 54 minutes  'Today bowling is too easy now when I was doing it in the 60's it was a spare game it was about precision'.  Here is the article he wrote for Wired magazine.

So when I was listening to this on the bus going from Otaniemi to Helsinki I hear about oil patterns and wrote something in my ipod 'surface tension of bowling and oil patterns'.  So I looked it up stuff about oil patches and how they can affect the surface tension of the ball going down the lane.  Oil patches in bowling are patches of oil left on the lane.  In the old days they used oil conditioners for the wood in bowling lanes.  After a while some of the oil would come off leaving less oily wood and possibly it was not always the same level of oil in the first place. So now like any sport tradition takes hold and the PBA (Professional Bowlers Association) uses various patterns to add some additional strategy to the sport.  For a list of patterns check here.

So what does this have to do with surface tension?  Everything.  The treating of the wood is very important.  The solvent based conditioners were developed a far back as the 40's and used within a specific era of bowling when they had to clean the bowling center by hand.  The solvents were added to the mineral oil which helped break the dirt down in the cleaning.  Later in the mid 80's and 90's as better products and urethane bowling balls became available the conditioners used had no solvents (100% solid conditioners with mineral oil being a main component in the 4-8 components).  Today high performance conditioners are popular and necessary for new bowling balls that have different contents of glass in them.  Mineral oil may be as low as 75%  in some formulas in the 14-16 components.  So as the bowling evolved different lane conditioners were used and different balls were changed.

Some things that affect these conditioners are noted: A) the viscoscity, B) surface tension (!) and C) temperature all affect the physical nature of the formulation being put onto the surface of the bowling lane and  how the bowling ball interacts with this surface.  The addition of the conditioners also has some affect as the chemicals may interact somehow.

A. Viscosity
It is the measure of the internal friction of a fluid. It is apparent when one layer is made to move against another layer.  The more friction between the two layers the greater force required to cause this movement of 'shear'.  Viscosity is measured in centipose (cps).  Honey for example can have viscosity of 3000 cps whereas water at 20 deg C has a viscosity of 1 cps.

How does this affect Billy Hardwick's bowling ball?  If there is a higher viscosity lane conditioner the ball will have more resistance to the floor which causes the ball to slow down and hook a little bit earlier.

B. Surface Tension

Since you have been reading my blog you already know surface tension.  The surface tension relates to the interaction of molecules at the surface of the water.  Surfactants like those found in floor conditioners will break this surface tension and allow it to spread across the floor easier.  The interaction with the solid floor would relate to the surface energy and the interaction with any mineral oil would relate to the interface tension between these two liquids.  The easiest way understand how the floor conditioner would spread across the surface and not bead up on the surface of the floor would be to measure the surface tension in relation to air using a tensiometer.

How does the surface tension and surface energy affect Billy Hardwick's ball?
The conditioner needs to recover after a ball rolls on it.  If a good conditioning is done to the floor then huge patches will not be evident after bowling many frames.  If not then Billy might want to try avoiding these patches.

C. Temperature

Pro bowling happens around many places in North America and the world.  One study from this website where I got a lot of material showed that for every 1 degree Farenheit (this is the US remember) the viscosity changes by 2 cps.  So for some lane conditioners if you start with a 20cps (viscosity) conditioner and the temperature drops from 80 ºF to 70ºF, the viscosity of that conditioner would be 40cps.

How would this affect Billy Hardwick's ball?  As mentioned above this can make the lane more slick or sticky depending on the temperature outside and conditioner used.  So if a professional bowler was playing in Helsinki on January 1st during the Brunswick Ballmaster Open (outside temperatures around -15 deg Celsius) it would have differed from the Kuwait Open in March (outside temperatures around 11-26 deg Celsius).  Since it is an inside game the temperature outside would only affect depending on the air conditioning or the heating system..

In summary the conditioner and the physiochemical properties of viscoscity & surface tension may affect performance.  Good bowlers should know about this and oil patterns that might be present on the surface.  For recreational bowlers like me that like to have a pint after every two frames and suck regardless of floor conditioner I don't think it matters so much.

Without further ado...Billy Hardwick.

Monday, 4 July 2011

The First American!

The 4th of July was made to celebrate the declaration of independence from the British.  One of the committee of five was Benjamin Franklin.  He was honored as being the first American for his early and indefatigable campaigning for colonial unity.  Benjamin also holds a large place in science.  He was a pretty great physicist.  Many people thought it was just a hobby but his contributions to science were quite astounding.  He made several inventions, scientific experiments and scientific queiries viz. wave theory of light, meteorology, lightning rod which later helped understanding electricity, oceanography and self assembly of monolayers. 

Franklin’s made an early account of monolayers by doing the oil-drop experiment to self-assembled monolayer structures.  Franklin must have read something from Pliny the Great whose ships at the back had smoother sailing then the ones at the front due to the cooks throwing large amounts of oil into ocean which collected on the trailing ships.  On a tour to England, Benjamin Franklin ventured out to a pond called Clapham where he stated that, “I fetched out a cruet of oil and dropped a little of it on the water. I saw it spread itself with surprising swiftness upon the surface… Though not more than a teaspoonful, produced an instant calm over a space several yards square which spread amazingly and extended itself gradually till it reached the lee side, making all that quarter of the pond, perhaps half an acre, as smooth as a looking glass.”“After this I contrived to take with me, whenever I went into the country, a little oil in the upper hollow joint of my bamboo cane, with which I might repeat the experiment and I found it constantly to succeed." 

This simple but pioneering experiment led to calculating the thickness of the monolayer, to making the langmuir-blodgett trough, discovering that cells are a bilayer, to lithography and material science to well, who knows?  Benjamin Franklin should be celebrated not just for his political savvy leading to independent America but also for his early monolayer work.  From stilling the raging seas to monolayers that are all the rage.  Benjamin Franklin's legacy continues

Warming ocean layers....

Coincidentally I just found this feed today:

Warming ocean layers will undermine polar ice sheets

                                Warming of the ocean's subsurface layers will melt underwater portions of the Greenland and Antarctic ice sheets faster than previously thought, according to new University of Arizona-led research. Such melting would increase the sea level more than already projected.

Sea surface microlayers

A couple of months ago I went to Amiens.  This small town in Normandy where Jule Vern lived and presided as mayor wrote some great science fiction/adventure novels.  I have read some of the father of science fiction and he has inspired me to write some as well.  This month I started reading 20,000 Leagues Under the Sea from Jules Vern.  This book with its very detailed account of islands, atolls, fish, mollusks, cestaceans and other aquatic life is so colorful I cannot put it down.  After reading a couple of paragraphs from the book I am reminded of some underwater adventures of my own to see the freshwater tropical fish in Lake Malawi, to the colorful red coral breathing on the bottom of the great barrier reef and feeding bread to surgeon fish in the Caribbean.  So after reading some of Jules Vern's masterpiece and with aquatic adventures of my own I wanted to relate it to science and this blog somehow.

Last year I went to Quebec and met some researchers from Croatia (another place I have visited to see the underwater life).  They were looking at characterization of sea-surface microlayers by monolayer techniques.  'Sea surface microlayers I asked?'  I had never heard of such things.   'The Sea surface (SML) is the top 1000 micrometers (or 1 millimeter) of the ocean surface.  So unlike Captain Nemo's Nautilus you do not have to go so far down into the ocean to explore this.  The Croatian researcher went onto explain that this boundary layer is where all the exchange occurs between the atmosphere and the ocean.  In relation to the book Captain Nemo exclaims 'that the ocean is a living organism with arteries ect.' so this boundary might be seen as the lungs for the ocean. Interestingly enough it is only at this surface that it occurs and the the chemical, physical, and biological properties of the SML differ greatly from the sub-surface water just a few centimeters beneath.  In the novel the ocean strata is quite complex and going down from 1mm, 1cm to one meter may change greatly in temperature, salt and other chemical compositions.

Strata of Ocean
By studying the SML with compressible monolayers and other devices like Brewster Angle Microscopy one can understand how these films work It was found that the mechanisms responsible for initial film formation and its later development are diffusion from the bulk and adsorption.  It is found that this layer of fat on the surface of the ocean is spontaneously made.  When you disrupt this layer with some toxin like surfactants, an oil spill or otherwise it can disrupt a lot of the oceans balance.  Polluting the water even the smallest 1 mm layer will be affected.  By studying these thin films you can understand the effects of the optical properties of the ocean, the pollution in the ocean and many other factors.  Just 1 mm can tell a lot!  Maybe when I venture from 20,000 Leagues to another literature classic Flatland I might get better insight into how 1 mm of fats on the ocean can effect many other things in our world.

Friday, 1 July 2011

When drugs and ink research collide....

Sometimes when you study inkjets and drugs or write about them (in the case of my previous posts ) you might be surprised that these two could come together to some sort of monster baby of cosmic proportions.  Well maybe not cosmic proportions but interesting ones nonetheless.  So when I saw this recently published article by Buanz et. al I was amazed at this stunning coincidence. 

This group wanted to 'evaluate the use of thermal ink-jetting as a method for dosing drugs onto oral films.' They replaced a regular Hewlett-Packard printer cartridge with a modified one so that an aqueous drug called salbutamol sulphate replaced the ink.  Buanz et al. wanted to find a better solution for personalized dosing.  'Personalized dosing cases where delivery of a precise dose is paramount, such as for highly potent actives,
drugs with a narrow therapeutic index, or paediatric formulations (where the dose is based on body mass), the individual dosage unit may need to be divided prior to administration.' A printer with thermoinjetting is something that is readily available and most likely easy to use.  The authors used
salbutamol sulphate an important drug for anyone suffering from asthma as it is a  is a short-acting β2-adrenergic receptor agonist used for the relief of bronchospasm.  They probably chose salbutamol because of its wettability properties and because it might be a drug where they have to vary the dose on the person.  

So what did they find?  They found that the viscoscity was important in this case for ink jet printing with  viscosities between 1.1 and 1.5 mm2 s-1 were found to be found optimal.  The surface tension was not as important but a minimum surface tension needed to jet satisfactorily is 35 mN m−1.  Aqueous ink has a
surface tension of 55 mN m−1.
  The solutions used in this  work had surface tensions from 46 to 71 mN m−1 so these had to be maintained to be within in jettability range.  They used the Kibron Delta-8 to maintain this surface tension above 35 mN m-1.   

In their experiment they used paper and a later a film made of potatoe starch.  Possibly the surface tension might need to be more strictly controlled if they use other solvents in the solution, or want to very accurate in the dosage and size of the tablet or if the drug is printed on other materials.  In any case they found: 'thermal injet printing offers a rapid method for extemporaneous preparation of personalized-dose medicines.'

P.S. I wonder if they got some of the ideas of inkjet printing from the people making acid blotter paper like the picture above.  Different technique used in this case however.