Four Distinguished MIT Professors Share Their Words of Wisdom



Founded in 1861 in Cambridge, the Massachusetts Institute of Technology (MIT), replete with an array of alumni Nobel Laureates, National Medal of Science Winners, and Rhodes Scholars, among other accolades, consistently in the U.S. News & World Report’s Top-10 Rankings, is universally recognized as one of the finest institutions of higher learning in the world.

Four distinguished Greek professors at MIT who are among the highest achievers in their respective fields spoke with The National Herald about their academic and scientific accomplishments, which are internationally acclaimed: Ioannis Yannas, Professor of Polymer Science and Engineering, recognized for inventing  the first regeneration template, a collagen scaffold that induces regeneration of skin; Constantinos Daskalakis, Associate Professor in Computer Science and Engineering, a 2012 Microsoft Research Faculty Fellow and has solved  a problem arising from John Nash’s work that had remained unresolved for 60 years; Gregory Stephanopoulos, Professor in Chemical Engineering and also Director of the Bioinformatics and Metabolic Engineering; and Sabine Iatridou, Professor of Linguistics, Syntax and Semantics, who has served as Director of the MIT Linguistics PhD Program for many years.


TNH: In May you were inducted into the National Inventors Hall of Fame as one of the highest achievers in your field recognized for inventing artificial skin. Please tell us about that honor.

IY: I feel very privileged that my work is being recognized. The term “artificial skin” was used in the late 1970s and early 1980s to describe a fundamentally new treatment for burned patients. However, the Hall of Fame citation correctly identified the true nature of our discovery: We had discovered a method for growing back (regenerating) an organ. Since these early days, both skin and peripheral nerves, as well as the conjunctiva (eye), have been regenerated. Our work has described the first treatment in the new field of medicine, referred to these days as regenerative medicine.

TNH: Your resume is full of publications, awards, and honors. In 1987 you became a Member of the Institute of Medicine of National Academy of Sciences, in 1988 you received the Doolittle Award of the American Chemical Society and in 1992 the Clemson Award for Applied Science and Engineering, Society for Biomaterials. What is the secret of your success besides research and study?

IY: Luck, number one; my very competent research students, number two; and my determination to stick with just one important research goal for my professional life.

TNH: Have Greek culture and education contributed to your success?

IY: My family taught me to rely on myself to solve the problems in my life. My early school education in Athens taught me to compete with my classmates but also to trust the rules of the game. When I arrived in the United States as a young man of 19 years, I had no idea how important these simple, basic rules would be in my effort to adapt to the culture of this country without losing my individuality as a Greek.

TNH: For years, some scientists did not understand the impact that their discovery would have. Was it the same in your case as well?

IY: Our discovery of a method of organ regeneration still remains to be fully appreciated by the larger medical community. You see, regeneration of an organ can do so much for people who have to live with diseased and dysfunctional organs, not only for organs that have been badly injured. These applications appear to emerge somewhere in the future; I wish they here with us today. Many problems that cannot be handled by organ transplantation (there are very few donors of organs) could be solved by regeneration treatments.

TNH: Describe an ordinary day for you.

IY: After having breakfast, I drive to the garage of my university, swim for half an hour, and then have meetings with research students and giving my classes. At the end of the day I am ready for some opera or the Boston Symphony.

TNH: Have you ever thought about going back to Greece in order to lend your expertise?

IY: A lot of nostalgic imagery comes to mind when I think about working in Greece. In reality, I am very happy with my life in the United States.


TNH: You were able to solve a problem that arose from Nash’s work, which stood unresolved since 1950. Many economists had been trying to find a solution, but with no results. What was the secret of your success?

CD: The contribution of my work was to characterize the computational complexity of Nash equilibrium, a concept defined by John Nash in 1950. The purpose of Nash Equilibrium is to predict what may occur in a non-cooperative game. A game is a mathematical abstraction of a strategic conflict between people. This may be a representation of some recreational game such as rock-paper-scissors, or it could model a nuclear conflict or an entire market. Nash showed that any game may find itself in a stable state whose characteristics he specified. This state is called Nash Equilibrium in his honor. Following Nash’s influential theorem, mathematicians and economists alike have strived to design algorithms for calculating Nash equilibria, and therefore predicting what happens in conflicts. Nevertheless, all proposed algorithms are computationally inefficient. What is worse, this has cast doubt into whether Nash equilibria may truly arise in practical situations. After all, if Nash equilibria are computationally intractable, then how can they possibly arise in practice? Motivated by this important question and inspired by the lack of progress for fifty years, my collaborators and I took a different perspective, showing something quite unexpected. We proved that there is no computationally efficient algorithm for Nash Equilibrium. That is, no matter how much scientist try, they will never be able to find such an algorithm, because it simply does not exist. The concept is inherently incomputable!

TNH: How can it be proved that a mathematical problem is unsolvable?

CD: Intuitively speaking, we should be able to solve any mathematical problem as long as we try hard enough, right? As it turns out this is not the case! Some mathematical problems are inherently unsolvable! Maybe the most prominent example is “squaring the circle,” a problem that bedeviled mathematicians since at least Anaxagoras, but was shown unsolvable in the 19th century. After several important problems were shown unsolvable in the 19th century, mathematicians’ aesthetic has changed to incorporate tools for establishing the insolvability of problems. Such mathematical machinery has been sharpened in the 20th century, and has trickled down into Computer Science, which is a child of Mathematical Logic. For our proof we develop the appropriate computational machinery to show the impossibility of computing Nash equilibrium.


TNH: When did you meet John Nash and what was your first impression of him during that meeting?

CD: I met John Nash in Chicago during the 2008 Congress of the Game Theory Society. Christos Papadimitriou, Paul Goldberg and I were receiving an award for our work on the computational complexity of the Nash equilibrium, and I was invited to present our result at the congress. I was astounded to see John Nash in my talk, and had the honor of presenting my doctoral research to the person who gave his name to Nash Equilibrium. Afterwards I had a conversation with him about the computational intractability of Nash equilibria. I was struck by his intelligence and clarity of mind.  In the group of extremely smart and talented people I am blessed to interact with, John Nash offered me one of the most intriguing conversations I have ever had.

TNH: In 2012 you solved another challenging problem that had been unsolved for thirty years. What was that about?

CD: As a whole, my research focuses on computational problems at the interface of Computer Science and Economics, particularly those relating to the design and study of the Internet. In addition to being a remarkable computational system, the Internet is also a complex socioeconomic system that lacks centralized design or governance. To gain a better understanding of its operation, computer scientists are applying economic principles to its study.

Through this research, we hope to gain a better understanding of what is happening in complex socioeconomic environments and how to design systems that have good properties when economic and computational phenomena take place at the same time.

My most recent findings have to do with the design of auctions. My students and I presented a new theory for the formerly elusive problem of selling multiple items under differing market conditions to maximize revenue, a problem left open by Myerson’s celebrated work on single-item auctions in 1981. This problem also has significant practical applications in sponsored search, online ad exchanges, and spectrum auctions.

The difficulty of identifying optimal multi-item auctions stems from the fact that the design space has such a large complexity that it seems infeasible to search over.  And even if one could search over this space, the optimal auction may just be too complex to be implementable. To maximize revenue, the auctioneer might have to agree to sell an item at some fraction of the highest bid, a fraction that could depend on a host of factors: the difference between the top two bids, the final price of the previous item on the docket, the populations from which the bidders are drawn, etc. We show how to overcome this apparent complexity barrier by viewing auction design as a geometric problem. We leverage our geometric understanding to identify optimal auctions that are relatively simple for the auctioneer and the bidders to keep track of.

TNH: What are you currently working on?

CD: I am working on problems at the interface of Computer Science, Economics and Probability. Besides the problems we have already discussed, I am fascinated by Machine Learning, the subfield of Artificial Intelligence exploring the design and analysis of algorithms that learn models from data, in order to make reliable predictions. Automated translation, and recommendation systems, such as those employed by Netflix, are good example applications. Within this field, I’m interested in problems arising in Computational Biology and the interface of Learning and Probability Theory.

TNH: Do you like the American lifestyle? How would you compare it to Greece?

CD: As far as my academic life is concerned, I really love being in the States. My students and colleagues at MIT are amazing and I find it a great pleasure and privilege to interact with them. On the other hand, I miss my homeland and some aspects of the Greek lifestyle. While Greeks do work a lot (unlike some stereotypes maintain), they also know how to enjoy their life more. I find that you should strive for balance in life, otherwise you may find yourself living only through your work. Work, I think, is too much of the focus in the States. Of course, things get more complex for scientists like myself, since science is not just work, but a passion.

TNH: What is your typical day like?

CD: Well, one of the things that I enjoy about academia is that every single day is different. This is a blessing and a curse at the same time. It is a blessing because you are mostly in charge of your own schedule, and a curse because you end up accepting too many tasks. In a usual weekday, I’ll find myself juggling teaching, research meetings, and university committees. When not doing all that, I love having a cup of coffee and thinking, catching up with my reading, or going to the movies.

TNH: What’s your opinion about the escalating political and economic turmoil in Greece? Have you ever considered to get politically engaged in order to help with your expertise?

CD: I find the situation that has been unfolding in Greece rather worrisome. It is quite unfortunate that, despite the obvious need for change, Greece has not been able to create an environment for exploiting well its remarkable human capital and natural resources. Instead of admitting the economy’s structural problems, a large part of the Greek population is still trying to find blame elsewhere, be it the Europeans or the immigrants. At the same time, Greek governments have been protecting economic interests and attacking the poor and the pensioners, creating a negative spiral that is shrinking the GDP. While Greece is perfectly capable to turn a corner and has a huge potential, some are working hard to keep the country in misery.

I have been asked to run for public office several times, but I would only consider it if I were inspired that there is potential for real change. It would also have to be the case that my expertise is useful, as I have no political aspirations for the sake of being a politician. For the time being, I prefer to offer my services to my homeland from where I am, continuing my academic career.

TNH: Do you think that the crisis has affected Greek education as well?

CD: Let me say first that for the size of our country it is quite impressive how much talent we have, as witnessed by world class recognition in science, art and entrepreneurship. If Greece could exploit this remarkable talent to its benefit, things would have been very different. Unfortunately, Greek academic institutions do not function the way they are supposed to. Funding is rather stingy. Classes are oversubscribed due to bad planning and corruption. Politics inside the universities are quite disruptive. Faculty hiring is often questionable. Research often does not meet international standards. What is worse, the Greek government is getting ready to bring changes that constitute negative progress. Without research excellence, Greece is doomed to lose its talented youth to other countries, and being a follower rather than a leader in innovation. Greece is capable of having top notch, internationally recognized academic institutions around which innovation and entrepreneurship will take place. To do this, we need funding and changes in governance. This is a high-stakes game for Greece and I hope the government realizes this soon. If rumors are true about imminent changes to education, they either seem to have a completely distorted image about what is needed, or are working hard to keep the country behind.

TNH: Would you ever go back to Greece?

CD: I miss my family, but as things stand I will stay in the States. I will continue to help my homeland in my current capacity.


TNH: Where were you raised and how did you become so successful and noteworthy?

GS: I was born in Kalamata, I went to a public school there until the third grade of Gymnasium (9th grade in the U.S.), when my family moved to Athens. My older brother George had succeeded in the Panhellenic University entrance exams (ranked first) for the School of Chemical Engineering of the National Technical University of Athens (NTUA). He was a great role model for me and my generation. So, three years later I also succeeded in the entrance examinations and matriculated in the same department. I graduated five years later, came to the United States for graduate studies, then to Caltech as Assistant Professor. I stayed in Pasadena, where Caltech was located, until 1985 when I received an offer for a full professorship from MIT, which I accepted, and I have been at this institution ever since. I did well at both Caltech and MIT. I think the reason was excellent role models (in family and society), strong family support and encouragement for pursuing excellence and distinguishing oneself, and, really, not serious viable alternatives (Plan B) in case my professional aspirations did not materialize.

TNH: A research initiative in the Chemical Engineering Department led by you examines a number of current and exciting topics in the area of Metabolic Engineering and its industrial and medical applications. Can you tell us more about it?

GS: Metabolic engineering is actually the engineering of the metabolism of microbes to convert them into little chemical factories that can synthesize numerous chemical and pharmaceutical products. They do so very efficiently, so that they can replace current chemical processes employed in the production of many chemical products we use in everyday life, such as biopolymers, biodiesel, oils and lipids, detergents, cosmetics, biopolymers and many, many others. These microbes can also synthesize complex pharmaceutical molecules more efficiently than by using traditional chemistry. As such, metabolic engineering is an enabling technology that can transform the chemical and pharmaceutical industries in the 21st century.

TNH: What are you currently working on?

GS: We do a lot of work in the area of biofuels, converting carbohydrate renewable feedstocks into lipids for biodiesel production. Also, we engineer microbes to synthesize natural products that are used as pharmaceuticals. One such example is to engineer the metabolic pathway that synthesizes the anticancer drug taxol. A large number of compounds (actually, more than 50,000) can be made by the same metabolic pathway and many of these compounds have important pharmaceutical properties. As such, our work aims at discovering such compounds and also providing an efficient method for their cost-effective manufacturing via fermentation. Other examples include compounds that are presently used for the production of packaging materials, antifreeze, components of the plastic bottles we use for water and soft drinks, and others. The major advantage for making these products using microorganisms and fermentation as opposed to fossil fuels is that their production is not associated with the release of greenhouse gases. In that sense they are truly “green” products that do not burden the environment with their production.

TNH: You are the Director of the Bioinformatics and Metabolic Engineering at MIT, which focuses on diverse challenges in the fields of Metabolic Engineering and Bioinformatics. Could you elaborate on that?

GS: As I mentioned previously, we are developing a number of methods for the production of biofuels, chemicals and pharmaceuticals using microorganisms. This entails the engineering of microbes using tools from modern molecular biology. In this form, we change the genetic makeup of these microbes in a targeted manner that modulates their genes and gene expression. It is these genetic changes that transform a microbe like a bacterium to a little chemical factory capable of producing the antifreeze compound ethylene glycol; or convert baker’s yeast to a different chemical factory that produces a pharmaceutical product, or specialized compounds that are useful as flavors and fragrances, just to name a few examples.

TNH: What is a typical day in your life like?

GS: There is, really, no such a thing as a typical day. There are so many things happening, some planned but many others totally unexpected. You can plan a visit, some meetings, regular lectures or faculty meetings: But there is no way you can anticipate developments in the lab, exciting and disappointing, news from other groups, funding agencies, journals where we publish our work or the personal lives of students and postdocs. They all make for an exciting life where there is hardly a dull moment! All of the above, sometimes in an orderly manner, sometimes randomly and unexpectedly, are the items that fill the life of an academic researcher/educator and make it incredibly exciting and very fulfilling.

TNH: Do you believe that institutions that are research-based are absolutely necessary in order for Greece to be a leader and not a follower in innovation, or can it be accomplished without it?

GS: There is no question that Greece needs advanced research and the innovation that results from it in order to maintain the high standard of living that our compatriots have come to expect. It has been proven over and over again that funds spent on research provide handsome returns unmatched by any other type of investment. Also, I cannot think of an advanced country with high standard of living that is not supported by robust academic institutions that serve as economic engines of their development. Greece’s most important asset is her highly educated and skilled professionals. They have proven over and again that they are capable of the highest achievements and distinctions when given the opportunity, mainly outside Greece. I do not see a reason that this model cannot be emulated in Greece proper to fuel the future economic development of the country. People will just have to set high standards and high expectations for students and professors, create a reward system that recognizes excellence and high achievement and show zero tolerance to attempts to dilute honest efforts aspiring to achieve high goals.


TNH: Please tell us about your early years and how you arrived at this point in your life.

SI:  I was born in Thessaloniki but spent my childhood in Holland, before going back to Greece and finishing high-school and college there. I did not  like what I was studying (dentistry), and I was constantly looking for other things that I might find  exciting and inspiring. I did not want to quit my studies, though, because I felt I would always have to explain that I could have, but did not want to finish. After I graduated with a DDS (Doctor of Dental Surgery) degree, I left for the University of Chicago to study anthropology. After a little over a year there, I saw a job advertised for a Research Assistant at an National Science Foundation project on Creole Languages at the University of Hawaii. Having been raised in Europe, I had not realized that Hawaii is mostly a vacation resort and I thought that I would find all sorts of adventures there. I did not find any adventures but I did discover linguistics. While I found anthropology, the study of cultures, interesting, I preferred the scientific methodology of linguistics, its formulation of working hypotheses, falsifiability, predictive power. The possibility of making language the object of scientific inquiry spoke to me. I found the notion of Universal Grammar in particular intriguing. This is the hypothesis that humans are born with an innate capacity for language and that languages are not consciously learned, the way we learn chess, for example. Universal Grammar in combination with exposure to the linguistic environment in which a child is raised together develop to the final language state that we call the child’s native language. Universal Grammar is responsible for the many deep commonalities between languages and also determines the space of possible languages. The specialization of linguistics called “theoretical linguistics” aims to explore, model, and understand Universal Grammar, as well as the parameters along which languages can differ. So, finally it seemed that I had found what I was looking for as a profession. After 2 years in Hawaii, I worked for a year at the University of Amsterdam, again as research assistant, and then went to MIT to do a PhD in Linguistics. After earning my PhD in 1991, I got my first job, which was as Assistant Professor in the Linguistics Department at the University of Pennsylvania. This was an excellent department but when I was offered the position at MIT, the pull to go back to my alma mater was irresistible and I came to back, as faculty this time, in January of 1997. I have been here ever since.

TNH: You served as Director of the MIT Linguistics PhD Program for many years and you are the author and co-author of innovative papers that have opened up whole new domains of research for the field. Is hard work the only secret key to your success?

SI: Well, I guess linguistics is like many things in life, in that it requires a combination of hard work and talent. What is not like that? But the secret to what you call my success, and it is actually not a secret at all, is that I am in one of the top linguistic programs in the world. My colleagues are the very best in their specializations. As a result, if I need to learn something, I have the opportunity to learn from the very best. If my colleagues were not what they are, or if I were in a smaller department, or isolated somewhere and forced to work on my own, my work would have been much, much poorer. So the short answer is that I have benefitted tremendously from the constant access I have to the top people in the field. We interact a lot, co-teach a lot, and co-author a lot. Also, our students (and when I say “students”, I mean our PhD students) are also among the best. They keep us on our toes and just the very fact that we are supposed to help them with their papers and theses and work overall, pushes us facilitates us to get better. So in short, the answer to your question is: the people around me and the interactive atmosphere in the department.”

TNH: Please describe a typical day in your life.

SI: I go to MIT between 8 and 9 in the morning, get home around 6pm for family dinner and then work in the evening at home.

This semester I teach six hours a week, in four intervals of one and a half hours each. Each class takes many hours to prepare, which I mostly do at home in the evenings:

During the day, at MIT, I am mostly in appointments with our PhD students, about five hours a day, one hour per student. Sometimes, I go to a colleague’s class or a talk. I also have certain administrative duties as program director but they can vary a lot, depending on the time of the semester. The rest of the time, is devoted to my research.

TNH: What is your biggest aspiration?

SI: My biggest aspiration is not work-related! I hope for a better world with social justice,  equal opportunities for everybody, no wars, and no unhappiness.






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