When Water and Air Meet: New Light Shed On Mysterious Structure of World's Most Common Liquid Interface

Science Daily  — Findings by researchers at the RIKEN Advanced Science Institute and their colleagues at Tohoku University and in the Netherlands have resolved a long-standing debate over the structure of water molecules at the water surface. Published in the Journal of The American Chemical Society, the research combines theoretical and experimental techniques to pinpoint, for the first time, the origin of water's unique surface properties in the interaction of water pairs at the air-water interface.

At the heart of this mystery are two broad bands in the vibrational spectrum for surface water resembling those of bulk ice and liquid water. Whether these bands are the result of hydrogen bonds themselves, of intramolecular coupling between hydrogen bonds within a single water molecule, or of intermolecular coupling between adjacent water molecules, is a source of heated debate. One popular but controversial hypothesis suggests one of the spectral bands corresponds to water forming an actual tetrahedral "ice-like" structure at the surface, but this interpretation raises issues of its own. The most abundant compound on Earth's surface, water is essential to life and has shaped the course of human civilization. As perhaps the most common liquid interface, the air-water interface offers insights into the surface properties of water in everything from atmospheric and environmental chemistry to cellular biology, to regenerative medicine. Yet despite its ubiquity, the structure of this interface has remained shrouded in mystery. The researchers set out to resolve this debate through a comprehensive study combining theory and experiment. For their experiments, they applied a powerful spectroscopy technique developed at RIKEN to selectively pick out surface molecules and rapidly measure their spectra. To eliminate coupling effects, which are difficult to reproduce in simulations, they used water diluted with D₂O (heavy water) and HOD (water with one hydrogen atom, H, replaced by deuterium, D). Doing so eliminates the coupling of OH bonds within a single molecule (since there is only one OH bond) and reduces the overall concentration of OH bonds in the solution, suppressing intermolecular coupling. With other influences removed, the researchers at last pinpointed the source of water's unique surface structure not in an "ice-like" structure, but in the strong hydrogen bonding between water pairs at the outermost surface. The extremely good match between experimental and theoretical results confirms this conclusion, at long last bringing clarity to the debate over the structure of the water surface and setting the groundwork for fundamental advances in a range of scientific fields.

Engineers Build Smart Petri Dish: Device Can Be Used for Medical Diagnostics, Imaging Cell Growth Continuously

The ePetri platform is built from Lego blocks and uses a smartphone as a light source. The imaging chip is seen in detail on the right. (Credit: Image courtesy of Guoan Zheng, California Institute of Technology)

Science Daily  — The cameras in our cell phones have dramatically changed the way we share the special moments in our lives, making photographs instantly available to friends and family. Now, the imaging sensor chips that form the heart of these built-in cameras are helping engineers at the California Institute of Technology (Caltech) transform the way cell cultures are imaged by serving as the platform for a "smart" petri dish.

Dubbed ePetri, the device is described in a paper that appears online this week in the Proceedings of the National Academy of Sciences(PNAS).

Since the late 1800s, biologists have used petri dishes primarily to grow cells. In the medical field, they are used to identify bacterial infections, such as tuberculosis. Conventional use of a petri dish requires that the cells being cultured be placed in an incubator to grow. As the sample grows, it is removed -- often numerous times -- from the incubator to be studied under a microscope.

Not so with the ePetri, whose platform does away with the need for bulky microscopes and significantly reduces human labor time, while improving the way in which the culture growth can be recorded.

"Our ePetri dish is a compact, small, lens-free microscopy imaging platform. We can directly track the cell culture or bacteria culture within the incubator," explains Guoan Zheng, lead author of the study and a graduate student in electrical engineering at Caltech. "The data from the ePetri dish automatically transfers to a computer outside the incubator by a cable connection. Therefore, this technology can significantly streamline and improve cell culture experiments by cutting down on human labor and contamination risks."

The team built the platform prototype using a Google smart phone, a commercially available cell-phone image sensor, and Lego building blocks. The culture is placed on the image-sensor chip, while the phone's LED screen is used as a scanning light source. The device is placed in an incubator with a wire running from the chip to a laptop outside the incubator. As the image sensor takes pictures of the culture, that information is sent out to the laptop, enabling the researchers to acquire and save images of the cells as they are growing in real time. The technology is particularly adept at imaging confluent cells -- those that grow very close to one another and typically cover the entire petri dish.

"Until now, imaging of confluent cell cultures has been a highly labor-intensive process in which the traditional microscope has to serve as an expensive and suboptimal workhorse," says Changhuei Yang, senior author of the study and professor of electrical engineering and bioengineering at Caltech. "What this technology allows us to do is create a system in which you can do wide field-of-view microscopy imaging of confluent cell samples. It capitalizes on the use of readily available image-sensor technology, which is found in all cell-phone cameras."

In addition to simplifying medical diagnostic tests, the ePetri platform may be useful in various other areas, such as drug screening and the detection of toxic compounds. It has also proved to be practical for use in basic research.

Caltech biologist Michael Elowitz, a coauthor on the study, has put the ePetri system to the test, using it to observe embryonic stem cells. Stem cells in different parts of a petri dish often behave differently, changing into various types of other, more specialized cells. Using a conventional microscope with its lens's limitations, a researcher effectively wears blinders and is only able to focus on one region of the petri dish at a time, says Elowitz. But by using the ePetri platform, Elowitz was able to follow the stem-cell changes over the entire surface of the device.

"It radically reconceives the whole idea of what a light microscope is," says Elowitz, a professor of biology and bioengineering at Caltech and a Howard Hughes Medical Institute investigator. "Instead of a large, heavy instrument full of delicate lenses, Yang and his team have invented a compact lightweight microscope with no lens at all, yet one that can still produce high-resolution images of living cells. Not only that, it can do so dynamically, following events over time in live cells, and across a wide range of spatial scales from the subcellular to the macroscopic."

Elowitz says the technology can capture things that would otherwise be difficult or impossible -- even with state-of-the-art light microscopes that are both much more complicated and much more expensive.

"With ePetri, you can survey the entire field at once, but still maintain the ability to 'zoom in' to any cells of interest," he says. "In this regard, perhaps it's a bit like an episode of CSI where they zoom in on what would otherwise be unresolvable details in a photograph."

Yang and his team believe the ePetri system is likely to open up a whole range of new approaches to many other biological systems as well. Since it is a platform technology, it can be applied to other devices. For example, ePetri could provide microscopy-imaging capabilities for other portable diagnostic lab-on-a-chip tools. The team is also working to build a self-contained system that would include its own small incubator. This advance would make the system more useful as a desktop diagnostic tool that could be housed in a doctor's office, reducing the need to send bacteria samples out to a lab for testing.

Funding support was provided by the Coulter Foundation.

Dancing To Their Wish

“The gopis would say, ‘If You dance, my dear Krishna, then I shall give You half a sweetmeat.’ By saying these words or by clapping their hands, all the gopis encouraged Krishna in different ways. At such times, although He was the supremely powerful Personality of Godhead, He would smile and dance according to their desire, as if He were a wooden doll in their hands. Sometimes He would sing very loudly, at their bidding. In this way, Krishna came completely under the control of the gopis.” (Shrimad Bhagavatam, 10.11.7) If the sweetest person you had ever seen was known to follow your command, to grant your wishes and delight your heart with His pastimes, wouldn’t you take advantage of the opportunity and find tremendous bliss and satisfaction whenever you wanted? This is exactly what a set of cowherd women did many thousands of years ago, as one small boy in particular had captured their hearts. With His every movement - His childish pranks, His muffled speech, and His delightful vision - He brought supreme happiness to everyone around Him. Since He was so kind, whatever was asked of Him in a sweet and loving mood He would do. What the commanders, the masters of this wonderful child, who was willingly acting like a puppet, didn’t know was that the person mesmerizing them was the Supreme Lord and that His willingness to follow orders given to Him in the mood of devotion extends to every single person. What does this mean exactly? If you are an atheist, you deny the existence of a supreme person, a controlling authority. There can be different reasons for having this viewpoint. Perhaps there is jealousy, envy over the fact that someone can be so powerful and have control over things that are seemingly uncontrollable. The opinion could also be attributed to just ignorance. Maybe no one has taught the person denying the existence of God anything tangible about spirituality. Perhaps their only exposure to religion has come from dealings with evangelists who claim that anyone who doesn’t accept their way is going to hell. “Why not sign me up then and leave me alone? If you crazy people are going to condemn me without any logical basis, why should I ever listen to anything you have to say?” Even if a verbal acceptance to the fact is absent, there is always a recognized higher power. To the person denying the existence of God, the higher authority is known as death. This force is acknowledged by every single person, for death is not a welcome event and yet it is something that no one can prevent. Despite the best efforts at prolonging life and even forgetting about the inevitable end of life through intoxication and willful ignorance, the dreaded end arrives all the same. Acting as the culminating blow of all-devouring time,kala, death comes and takes everything away from the individual. Every relationship we have, every plan we have made regarding the future, and all the knowledge we have painstakingly acquired gets wiped away in an instant. This last fact is a little disconcerting. Knowledge is gathered not only through explicit study, but through difficult experiences as well. Think about the worst events of your life and how you felt when they were taking place. Though the events were traumatic and difficult to cope with, eventually some lesson was derived from them. Therefore the acquisition of knowledge involved some pain. Now, just imagine having to do that all over again! The Vedas, the ancient scriptures of India, reveal that the spirit soul is the essence of identity. A tiny spark, which is no larger in size than the tip of a hair divided into a thousand pieces, the spirit soul exists perpetually. Death cannot take away the soul and birth cannot create it. The soul has always been the soul; it has never lost its identity. “Know that which pervades the entire body is indestructible. No one is able to destroy the imperishable soul.” (Lord Krishna,Bhagavad-gita, 2.17) Birth and death are the acceptance and rejection of temporary dwellings, sort of like moving in and out of an apartment. When the individual doesn’t know any better and thinks that the place they moved into is the only establishment they will ever occupy, the eventual moving out is dreaded. It is so feared that many steps are taken to try to forget it, the day when the lease will be up. Whether there is an acknowledgment or not, the final day will still come. The wise person, he who sees through the self-realized vision acquired through study of a bona fide system of spirituality, understands that just as the dwelling was accepted at some point, so it must be renounced. Despite the moving in and out, the person occupying said establishment never ceases to be. Neither is there only one dwelling for a single person. Is there only one house for every person in a community? Is there only one place to live in the entire world? The soul is so tiny in size that it can live practically anywhere. Ants live in the ground, bats in caves, fish in water, birds in trees, and the human beings on land. What these species have in common is that their identities come from the localized soul, hence the entities are really the same in quality. What is unique to the human species, however, is the ability to know and serve God. Just knowing about death indicates a step up in intelligence from the other species. When God is known only in His form of all-devouring time, nothing can really come from that knowledge. Perhaps one will futilely try to enjoy as much as possible before moving out day, but since the spirit soul transmigrates from one body type to another, the next moving in day will arrive all the same. These facts are revealed in the Bhagavad-gita, the Song of God sung by Lord Krishnaon the battlefield of Kurukshetra some five thousand years ago. Should we be hesitant to accept words from a foreign scripture compiled so long ago, we can still see evidence of the temporary changes through our own experiences. The personal dwelling is completely different during childhood than it is during adulthood, yet the identity of the occupant doesn’t change. Why then should there be such attention given to the full changing of abodes that occurs at death? A step up from knowing about death is understanding that there is intelligence behind the workings of nature. The human being innately understands that God exists and that His position is supreme. Show young children pictures of Krishna or a celebrated form of God and they somehow will adopt the reverence that goes into worshiping the Supreme Lord. This type of devotional interaction is known as shanta-rasa, or the transcendental mellow of neutrality. In this exchange of emotion, there is acknowledgement of God’s superior position, but since He is too awesome in scope, the devotee doesn’t go beyond admiration.  One way to picture this is to think of visiting a temple and being sort of afraid of the deity that everyone looks at. Shanta-rasa is considered devotion because there is an acknowledgement of a higher power, and there is respect shown to Him. Without respecting someone who is in a superior position, how can we ever gain their favor? Indeed, the Supreme Lord’s benevolence is available to everyone, but only the devotees know how to make the best use of the divine gifts granted to them. How does this work exactly? Let’s say that we have two people living in a home that has electricity. Since the utilities bill is paid for, there will be power coming through the various outlets in the house. The ignorant may mistakenly place their fingers, or worse, metal objects, into the sockets. This is obviously not the right way to use the electricity. The person in knowledge, however, will plug their appliances and electronic devices into the sockets to get electrical power. This is what the power is there for in the first place. This method also won’t cause any personal injury, as the electricity will safely travel through the wires. The electricity is present for both persons, the ignorant and the knowledgeable, but only the person who knows how to use the electricity will gain a benefit from it. Similarly, only the devotee, he who acknowledges the existence of God, can make the most out of their human form of body, a species that has the highest potential for intelligence. Beyond shanta-rasa are other transcendental mellows that shed some of the veneration, thus allowing for more intimate interactions with God. The gopis of Vrindavana exhibited behavior towards the Supreme Lord that went well beyond basic respect. They were so attached to Krishna that they commanded Him, and He did as they asked. How can a person command God to do anything? Think of a child who tells their father or mother to do something. Obviously the parents don’t have to listen, as the child is the dependent and the parent the guardian. But if the child is loved and adored and the requests offered in a mood of love, the parents will voluntarily submit to the child’s wishes. The living entities populating the many universes are all God’s children, but only those who are devoted to the Lord can have the benefit of being able to ask Him to do something and Him following suit. The most fortunate individuals in the world are those who are blessed with the Supreme Lord’s personal presence. What is the difference between a personal presence and an impersonal one? The impersonal doesn’t allow for devotional interaction. God and His energies are not different; therefore the Lord is actually everywhere. He is resting within our hearts as the Paramatma, and also within the grass, the atom, the trees, the sky, etc. He is everywhere; we just don’t have the proper eyes to see Him. When His influence is recognized, there is an impersonal understanding of God, that the Supreme Lord has energies that He can command. With personal interaction, the Personality of Godhead and His spiritual forms and attributes are recognized. More than just being familiar with these features, the devotees remember them and derive tremendous satisfaction from glorifying them. Therefore it is not surprising that the next step up from impersonal worship and devotion in neutrality would be to personally interact with the supreme person being worshiped. The Vedas say that God’s original and most blissful form is that of Shyamasundara, the beautiful youth with a blackish complexion. Since He is all-attractive, He is also known as Krishna. Shri Krishna descended to this earth some five thousand years ago and acted like an ordinary child in the town of Vrindavana. Since He roamed the earth in a spiritual form, sometimes it is said that the Supreme Lord took on the form of a child to delight the residents of the sacred land of Vrajabhumi. These statements don’t mean that God accepts a material form, but rather that He takes on spiritual manifestations to give delight and pleasure to His adherents. If He retained a gigantic form, one that was awe-inspiring, how could anyone ever get past the stage of shanta-rasa? What exactly is the benefit to shedding one’s veneration for God? Shouldn’t we have respect for the most powerful person? Actually, when following a transcendental mellow the more that veneration is renounced, the greater the pleasure there is for Krishna. Imagine being a celebrity and having everyone adore you all the time. Obviously it would be nice to be praised in this way, but then you also wouldn’t have any friends. A friend is someone who looks at you as an equal, a peer. This relationship is nice because you can have real conversations and people can take note of your interests without being afraid of you. The parent is also intimately related, as they take care of you, not paying any attention to your celebrity status. The life partner is even more intimately related, as they love you romantically and cherish your association. For the famous person, these relationships are relished far more than the interactions with fans who simply heap praise. For the Supreme Lord, the interactions He has with devotees like the residents of Vrindavana give Him the most pleasure. Vrindavana was a farm community heavily dependent on cows, so even the women worked. They managed the household affairs, helped in the production of milk products, and also took care of the children. The glories of the gopis can never be fully enumerated. They were independent women; except they voluntarily chose in favor of devotion to Krishna. This starting point enabled them to have the knowledge necessary to complete life’s other tasks to perfection. The gopis were varied in age. The elderly gopis were friends of Mother Yashoda, Krishna’s foster mother. These women especially loved interacting with young Krishna, who was their very life and soul. Though He was Yashoda’s son, they treated Him as their own, delighting in every chance to meet and talk with Him. The gopis would encourage Krishna to dance by rewarding Him with various sweets. They would also coax Him into singing very loudly. Krishna is so wonderful that even His childish speech delights the heart. If there were prohibitive veneration for God in His most blissful form, if the gopis knew that Krishna was the very same Vishnu they were accustomed to worshiping, how could anyone have ever commanded Him like this? Shri Krishna followed the commands of the gopis because they were devotees. Those inimical to both God and the saintly class are never given such a benediction. The ignorant can at best hope to misuse to different degrees the energies Krishna kindly distributes everywhere, while the devotees can rise in stature to the point that the Lord Himself will follow their orders. Seeing both options, the proper path to take in life is quite obvious. Follow bhakti-yoga, or devotional service, and become fully endeared to the master of all senses, Hrishikesha. His blissful form is there to be enjoyed, to be the sweet nectar for the eyes. The sounds of His names found in the sacred maha-mantra, “Hare Krishna Hare Krishna, Krishna Krishna, Hare Hare, Hare Rama Hare Rama, Rama Rama, Hare Hare”, are meant to please the ears. Invigorate your senses by indulging them in Krishna consciousness; immerse the mind in the holy lake of the Supreme Lord’s acts. With the bhakti formula your life will be successful and you will always be in God’s favor. In Closing: Seeing Him gopis never miss the chance, To make their beloved young Krishna dance. With reward of sweetmeats Him do they entice, To taste delights dancing for them is the price. They encouraged Yashoda’s son with their clapping, Smiling sweetly Krishna obliged by dancing. No one knew the true nature of Yashoda’s son, That He created this world and every other one. His position as God they did not know of, So all they could give to Him was their love. From devotion only can one Krishna please, Bhakta’s desires God delivers with ease. Hear of gopis making young Krishna sing, And felicity to your heart right away bring. Misuse God’s energies or to Krishna become dear, Reward of Lord’s company makes right choice rather clear.