Pores and drops: Made to order.

Porous solids are mundane materials.  Well, by making such a statement we are not certainly undermining their importance in the realm of science and technology.  From the very simple pumice stone for pedicure to the highly sophisticated zeolites , the utility of porous solids can never be undermined.  A recent paper in Nature not only announces the possibility of porous liquids, but also demonstrates the concept.   Another paper discusses self-shaping oil droplets. In both cases  simplicity of the concepts and approach are commendable.  

First about the porous liquids.  According to well established theories, dissolution of  a solute in a liquid is the process of carving out cavities to house the solute.

There are several physical and  chemical forces at play. Giri et al asked the question why not have pre-fabricated pores/cavities in the solvent ? There  are indeed conditions. The molecular dimensions of the pore  can't be  bigger than that of the  solvent molecule. Why not? Because then the solvent molecules will reside inside these pores happily ever after.  So the team chose 15 Crown 5 ether, a liquid at room temperature, as the solvent. They fabricated  the cage molecule from crown ether functionalized diamine.  This cage  has a cavity size of about 5 angstrom diameter. The solvent could dissolve  up to 44 wt % of the cage molecules   and still retain fluidity.  While the molecular dynamics simulation studies provided theoretical and structural information about the nature of the porous liquid, actual experiments demonstrated the ability of the pores to absorb and desorb  gases such as nitrogen, methane, carbon dioxide and xenon. With appropriate competitors these gas molecules could be forcibly evicted too.  

Denkov et al. demonstrate  that they can  shape oil droplets, and freeze those shapes. Again the experimental set up is extremely simple.  Recipe calls for water as the medium,  surfactant (ionic or non-ionic)  as an additive, and linear  long chain hydrocarbons with 14-20 carbon atoms, (as the  oil, the droplet former). It is imperative that the chemistry of the surfactant and the hydrocarbon should match, that is the alkyl chain length of the surfactant should be equal to or longer than the hydrocarbon chain length. Other decisive factors include the initial drop size and temperature. Or to be more precise the rate of cooling. In a typical experiment with hexadecane (C16H34) in aqueous medium containing 1.5 wt% Brij 58 (a non ionic surfactant with the formula C16H33(CH2CH2O)20OH)  the team captured the shape transformations of the droplet under varying rates of cooling. These shape transformations are induced by the phase transitions that occur within the oil droplet. At any stage these shapes can be selectively frozen. 

References 

1.  Liquids with permanent porosity : Giri et al. Nature Vol. 527, 12 Nov. 2015, pp 216-220

2. Self-shaping of oil droplets via formation of intermediate rotator phases upon cooling  Denkov et al Nature Vol 528, 17 Dec. 2015 pp 392-395

@ Vienna :TWAS 2015

Austrian Academy of Sciences

Frescoes inside the seminar hall

The  26th Annual general meeting of The World Academy of Sciences (TWAS) was held at Vienna this November. Austrian Academy of Sciences hosted the meeting and naturally the venue was the Academy itself.  This imposing historic building built in 1755 and  inaugurated by Maria Theresa originally housed the University of Vienna. During the 1848 revolution, the building catered to military needs accommodating soldiers. It was in 1857 that the Kaiserliche Academie der Wissenschaften ( Imperial Academy of Sciences) moved in here.  In 1947 its name was changed to Austrian Academy of Sciences.  The frescoes inside the building are   beautiful. The  side panels represent four traditional branches of knowledge of the University: Theology, jurisprudence,philosophy and medicine. These were painted by Gregorio Guglielmi. 

This year's theme for the conference was Sustainable Development and how science and scientists can enable and accelerate these process. Delivering the  keynote lecture, Albert Louis Sachs however cautioned that sustainable Development Goals (SDGs) must necessarily  include the needs of the poor.  Sachs had served as one of the six judges in the Constitutional Court of South Africa for fifteen years from 1994-2009. He highlighted the case of Grootboom V Constitutional court of South Africa.  Adequate housing is guaranteed in the constitution of South Africa and the SA Government identified several plots of lands to build low cost housing. However due to a combination of circumstances helpless people such as Grootboom and several others had to pitch huts in one of these plots.  SA Government evicted them, without providing any alternative.  Grootboom went to the court.  The case came up before Albert Sachs. He judgement  was in favor of Grootboom, however it is another story that Irene Grootboom died in a shanty at the age of 39.


A roof and at least one square meal- demands of the poor are so minimal. But  that  doesn't mean they  can be sidelined or totally excluded  when the rest of the world makes plans for a better  future.  This brings into sharp focus contemporary concerns in several developing  countries. In the name of development agricultural lands are being erased and forest areas are encroached into. Balanced and all inclusive equations alone would lead to sustainable development. 

Tailpiece
 At one stage Vienna was the power center of Europe and empress Maria Theresa decided the fate of the continent. Palaces,and churches ...  the city has so many attractions .Vienna was also the musical capital and  we indulged   ourselves in  a concert at the Mozarthauz. Mozarthauz is the oldest concert hall in Vienna where Mozart used to entertain  Bishop Colloredo.  And then, of course Vienna is also the city of Freud. His house is a museum now.    

At the Freud Museum 

 Inside the Mozarthauz

''Pot''ful of medicines

For decades  intoxicating heavy smoke has  hid the medical benefits of the pot . Because of this,  Governments   outlawed the poor plant Cannabis Sativa together with its cousins  indica and ruderalis, root, stalk and leaves. But  how long can you suppress scientific curiosity?    Now scientists want to relook at the plant and the chemicals it produces, because they believe cannabinoids( a general term for chemicals derived from the plant) could lead to very useful  pharmaceutical products.  Governmental regulations in some countries have loosened their grip to allow enough flexibility for scientific research. 

It is assumed that Cannabis plant originated  in central Asia  and spread across the globe. Humans made use of the plant mainly for the grain and  fiber  (hemp). Somewhere around 2700 BC , Chinese emperor Shen Nung  discovered the medicinal potential  of the plant. Its leaves or buds were burnt and smoke inhaled to relieve pain. Millenniums later,while working at the Medical College of Calcutta, India,  W.B O'Shaughnessy an  Irish doctor,  discovered the use of Cannabis among the natives both as a medicine  as well as recreational drug.  In October 1839 , he presented a paper  On the preparations of the Indian Hemp (orGunjah) .  Portuguese physician  Garcia de Orta,  spent  better part of his life in India researching tropical medicines. In his book Colloquies on the simples and drugs of India gives a detailed account of  Bangue, Cannabis indica.    But these were  not exactly systematic scientific studies and hence the medical benefits  of Cannabis remained unsubstantiated.  That is the flashback for Marijuana the grass and its  crudely refined products hashish/charas.

 On the leaves and buds  the plant  bears  little pimple like protrusions called trichomes and these are rich in a variety of chemicals classified as   cannabinoids, terpenes etc.  The poor plant produces these chemicals for a variety of reasons  for example to  to lessen moisture loss, to ward off predators and to shield off ultraviolet rays. Reading O'Shaughnessy's paper British  chemists were excited and they isolated   Cannabinol from the plant extract   in 1899.     

 Cannabis flowers with Trichome
Courtesy Wikipedia 

Cannabinol: Courtsey:Wikipedia

Chemists  were  just rolling up their sleeves to dig  deeper into the  plant concoctions to isolate more active ingredients, but alas  International Regulations and  Laws banned the    handling and use of psychotropic substances. Special pemissions had to be obtained to work on all narcotics. But  there  are those  who are not easily deterred.  And hence a few groups toiled on. Israeli chemist Mechoulam isolated the one and only  psychotropic ingredient in Cannabis,  Tetra Hydro Cannabinol (THC). It was indeed a huge morale boost for them when follow up studies by  neuro pharmacologists  showed  that  humans have built in receptors CB1 and CB2 specially reserved for Cannabinoids. That meant two things:   the human  body is  equipped  to receive cannabinoidlike chemicals and might actually be producing some ! Of these receptors  CB1 type is  found mostly in the central nervous system and CB2 in the immune system.   In  2014, a review appeared in the journal of American Academy of Neurology on the Efficacy and safety  of medical marijuana in selected neurologial disorders. . 

Cannabidiol(CBD) Courtesy: wikipedia

Tetra Hydro cannabinol(THC)
Courtesy: wikipedia

GW pharmaceuticals based in UK  holds permission for conducting research in cannabinoids. A mouthspray developed from whole cannabis extract is approved in several countries for treatment of spasticity in multiple sclerosis patients. Another  drug  for epilepsy will soon be in market.  

Reference 

1. Cannabis Outlook: Nature 24 September 2015. 

Desert Tales

Africa : NASA picture 

In the scorching sands of Saharan desert why doesn't the Cataglyphis bombycina get roasted like a peanut? These tiny creatures  go by the common name Saharan silver ants. As the name suggests these ants  are native to  the  hot Saharan desert and have a silvery glaze. Saharan desert, stretching across northern Africa,  skirted  by the Atlantic ocean on the west, the Red sea on the East and the Mediterranean sea on the north  is not at all a friendly terrain to pitch a hut.  Here ambient   temperature can soar to 54 degree Celsius and sand temperature could be as high as 80 deg.C. Most of the desert creatures are crepuscular, that is they come out either during dawn or dusk. But alas   poor silver ants can't afford to forage during  twilight hours  because of predators. So to avoid being caught and made into a meal these  ants forage when the predators are having  their siesta; that is  at noon, when the Sun is at the peak. Professor Rüdiger   Wehner and his team at the University of Zurich have been fascinated by these ants for quite some time.   They   have been looking into the   the neurophysiology and behavioral pattern of these ants with special emphasis on vision as  a strong cognitive capability. In the 17th July issue of Science magazine  Professor Wehner and his team provide  answers to the critical question : How do these tiny insects keep their cool ?   They could very well  have asked why are these ants so shiny.

Community dinner: courtesy wikipedia

  

There are  several interesting things about C. bombycina.   Their   unusually   long legs  lift the body 4-5 mm above the ground. Such high ground clearance means, the ellipsoidal body, not more than a cm in size is considerably cooler than the scorching sand below. Long legs also mean speed. These ants  can run  fast and far off in search of food. This has been captured in a excellent video. If it goes far off, how does it get back to its burrough? It seems smell and sights of the starting point stored in their brain  guide it safely back to home ground.

But how does it ward off the heat? Prof. Wehner and   his team provide the answers in their paper. The silvery sheen is not just a beauty enhancer. It is indeed a very effective thermoregulation feature. The shine  is due to a thick mop of fine silvery hair covering the dorsal and lateral sides of the body. The morphology of the hair has been studied by electron microscopy .  triangular cross section and taper off to the tip. These hairs perform  multiple tasks, strictly in accordance with the Laws of Physics. The triangular surfaces facilitate   total internal reflection and thus enhance reflectivity in the visible and near infra-red regions of the solar spectrum and      in the mid infrared region the hair layer demonstrates  very high emissivity. In other words exactly opposite of what  solar panels do. For excellent performance a typical solar heating panel must have zero reflectivity ( very high absorprtivity) at low wavelengths to capture maximum heat  and very low emissivity at high wavelengths to minimize radiation heat loss.

Desert creatures have evolved  several  adaptive strategies to encounter the twin threats of high heat and lack of water.  For example certain types of desert  rodents  generate water as a metabolic by-product.  At the cellular level, heat shock proteins  see to it that   heat and dryness don't impair the structure and hence the function of biological molecules.  

References:

1.  Keeping cool: Enhanced optical reflection and radiative heat dissipation in Saharan silver ants. Nan Shi et al Science 17 July 2015 vo. 349 pp 298-301

2. Smells like home: Desert ants cataglyphis fortis use olefactory landmarks to pinpoint the nests 
3. The amazing Cataglyphis ant
4. Passive radiative cooling below ambient air temperature  under direct sunlight: Raman et al  Nature 515.pp540-44(2014)
5.Heat Shock protein synthesis and thermotolerance in cataglyphis, an ant from Saharan desert -Gehring and Wehner : PNAS 92, 2994- 2998 (19995)

On Information : Transmission & Storage.

What happens if the information superhighway- (or infobahn if you prefer) gets clogged? Choc-a-block like any other highway? The rate at which new users hop on to internet, this indeed is a possibility, though the danger is not imminent.   Traffic in the information superhighway  has been increasing   by 60% annually for the last 15 years. Though we haven't yet reached danger level, still it is imperative that we take note of the situation and have solutions in place.  

Courtsy: wikipedia

Silica, the material used for optical fiber,  has exceptional properties. Extremely low signal loss (attenuation coefficient ~4.6x10^-5m^-1) and an equally small nonlinear refractive index -(n₂₌2.5x10^-20m²W^-1 ). So light undergoes total internal reflection inside the hollow fiber wth the walls just containing and steering its its path. But overcrowding can change all that. Nonlinear error (also called Kerr effect) could add up over volume and distance and distort signals. Another term used for such distortion is crosstalk.  A  fiber material with  n₂=0, will be the ideal solution.  In that case there will be no interference and no cross-talk whatsoever. 

Professor Radic and his team at the University of California, San Diego thought differently. What if we can cancel these nonlinear responses?  To achieve this Radic and team designed  "frequency combs" which synchronized the frequency variations in the optical data flow and  demonstrated that carrier coherence is the critical requirement to eliminate crosstalk. Because under such circumstances cross-talk is predictable and reversible.  Their results are published in the 26th June issue of Science. This study implies possibilities beyond the current limits of the reach and volume in optical fiber communication. 

Transmission is one thing; what about storage? Just to cite an example: Human Genome Project and  International Cancer Genome Consortium (ICGC) would have by generated data running into  petabytes.(One petabyte =10¹⁵ bytes ). Cloud Services (which includes storage and computing facilities) is one platform where such enormous volume of data could reside. This would provide easy and fast access and usage to multiple research teams across the globe. Of course there is price tag attached. Currently alongside titans such as Amazon, Google and Microsoft, there are smaller firms too offering this service.  It is reliably learned that National Institutes of Health, USA  will soon move some of its information wealth  to a cloud storage facility. Europe is perhaps is planning its own version. 

But some remain skeptical, what if your cloud bank  bursts?.  

Reference:
1.Overcoming Kerr-induced capacity limit in optical fiber transmission. Temprana et al Science: 26 June 2015 pp1445-48. 
2.Cloud Cover: Nature 9 July 2015 pp 128
3.Create a cloud Commons:Stein et al  Nature 9 July 2015 pp 149-151.
4.Europe sets its sights on Cloud: Gibney,E-Nature 9 July 2015 pp136-37 
5 Cloud's worst case scenario- What to do if your provider goes belly up

Man to Machine: "Think,Decide, Act!."

The kind of acrobatics that robots are called upon to perform  in science fiction novels/ movies , would certainly cost them an arm or a leg. However in SF Imagination is unbound and  the limbs regrow  in a jiffy.  But alas!  Imagination and Reality are not so close neighbors.   Currently  a reality  check is being done on   the possible options available for a robot injured  in  action, in the battle field. Their focus is to  design robots that can adapt like animals. (1,2). Living beings possess natural instincts accumulated over time, and also revised/ refined through learning and memory, to adapt to unexpected and uncertain situations. Cully et al  equipped the robot with   a  unique trial and error algorithm (a behaviour-performance map with weighted values)   The algorithm contained   a number of possible failure modes and their corresponding most optimal responses. So to begin with Cully et al envisaged   a robot injured  in about 19 different ways, with  broken arm or a leg.   Empowered with  this  behavior-performance map,  the robot could manage the situation in less than 2 minutes.  The leader of the team Jean-Baptistre Mouret says "I study machine learning and evolutionary computation to design highly adaptive robots". Mouret's website presents  several, very  interesting videos  that explains it all.  

Courtesy: wikipedia

Just about a year ago   we were amazed how a paraplegic equipped with an exoskeleton propped by an array of electronic devices, proved a point  (World Cup 2014: The symbolic first kick).  A year later Aflalo and team show that an intention  can actually be translated  into an action(3,4). The volunteer,   EGS,   is paralyzed from neck down for the past ten years, but   nerve cells in his  posterior parietal cortex is still active. Posterior parietal cortex is the main area where prework for an action, happens,  in other words  intentionality. Aflalo etal detected that EGS's thought processes selectively fire  nerve cells in this area. The team  took a cue from this and began a process of reading his thoughts. Each time they could check with him whether they read correctly; that was an added advantage. The research team tapped the signals via tiny silicon chips embedded in the brain and then fed into a robotic arm or a computer screen to move the cursor.These silicone chips, an array of 96 microscopic electrodes have been approved by the USFDA (United States Food and Drug Administration ) for commercialization.  A  definite step forward in the development of  next generation neuro-prosthetic devices.  Videos are available at Professor Richard Andersen's webpage. 

References:
1. Robots that can adapt like animals : Cully etal Nature 28 May 2015 pp503-507 
2.Robots with instincts : Adami: Nature 28 May 2015 pp 426-427
3.Decoding motor imagery from the posterior parietal cortex of a tetraplegic human :Aflalo etal Science 22 May 2015, pp906-910 
4. Reading the mind to move the body: Pruszynski & Diedriehsen Science 22 May 2015 pp 860-861

Hubble Telescope : 25 years in the sky

It is indeed party time.   You have an open invite to  join the celebrations. For a quarter of a century,since its launch on 24th April 1990, Hubble space telescope has been functioning as our  eyes  in the sky  with a unique mission. Tracing galactic histories, witnessing  cosmic events, unraveling the mysteries of black holes, dark matter, dark energy.....

There were initial hiccups.  Though Hubble began transmitting pictures within a couple of months, they were of poor quality .   It took three and a half years to fix a defective  reflector. In January 1994, earth station received the first clear pictures from Hubble. Then on 2nd November 1995, Hubble transmitted its first masterpiece the Pillars of Creation, a composite of 32 frames  from 4 individual cameras. An unbelievably beautiful and enigmatic   insight into  the formation of a star. How  a nascent star draws  raw material from these gaseous columns  of hydrogen gas and cosmic dust.   Hubble has been  relaying information about  the universe; information  hitherto unknown and unsuspected

Pillars of creation :Eagle Nebula M16
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

In 1999  when the comet Shoemaker-Levy 9 crashed into planet Jupiter,  Hubble  enjoyed a ringside seat. It stood  witness to an amazing  cosmic accident.  Jupiter's  enormous gravitational pull   disintegrated the comet  into several pieces and as they fell,  violent shock waves were generated. Equally fascinating  was the visual proof of dark matter in a set of galaxy cluster collision images captured by Hubble and Chandra, the X-ray observatory. While Chandra glued its eyes on the hot gas emissions, Hubble observed the uncanny ability of  invisible dark matter to warp space and  thus deforming the images of heavenly bodies in the background

. 

six galaxy cluster collisions with dark matter maps.
 Courtsey: HubbleSite

 ''

Hubble  is  being periodically serviced  and could now be  well like the ship of Theseus, with most of its parts repaired or replaced. But its time is up.  Hubble  will be retired  from active service by 2020. Its successor, the  next generation James Webb Space Telescope(JWST) will be launched by 2018.  JWST,will carry a telescope roughly the size of a tennis-court with sharper    infra-red vision.  It is described as an observatory that folds up inside a rocket for launch and unfurls like a butterfly opening its wings upon nearing its orbit. 

Edwin Powell Hubble was a world renowned Astronomer. But   Who is James Webb ?  Jim Webb is neither a scientist nor an engineer. He was an efficient administrator.  Second person to head  the nascent yet mighty NASA, he  could hold his own in  the power corridors of Washington D.C and deftly negotiate the bureaucratic labyrinths,  Jim Webb set the space program of NASA on a solid footing.   

Dusty spiral galaxy ngc4414Image Credit: The Hubble Heritage Team (AURA/STScI/NASA)