bbell2's picture

John D. Roberts Awarded AIC Gold Medal

John D. Roberts, Institute Professor of Chemistry, Emeritus, at the California Institute of Technology (Caltech) received the 2013 American Institute of Chemists Gold Medal. The AIC awarded the medal to Roberts at the Heritage Day event in April in Philadelphia hosted by its awarding partner, the Chemical Heritage Foundation (CHF).

The AIC established the Gold Medal, its highest award, in 1926 to recognize service to the science of chemistry and to the profession of chemist and chemical engineer in the United States. The Gold Medal has been presented jointly by the AIC and the CHF since 2003.

"I am very honored to have been selected to receive the American Institute of Chemists Gold Medal," Roberts says. "Throughout my career, I have been fortunate in being able to collaborate with the world's leading researchers, study and teach in highly respected institutions, and participate in some of the most important scientific discoveries since the middle of the 20th century."

Roberts is an expert on the leading research into the mechanisms of organic reactions, the chemistry of small ring compounds, and applications of nuclear magnetic resonance (NMR) spectroscopy to organic chemistry and biochemistry. He serves on the boards of directors of Organic Syntheses Inc. and University Science Books, and was a consultant to DuPont from 1950 to 2008.

Roberts received his Ph.D. in chemistry from UCLA in 1944. Following a period as an instructor in chemistry there, Roberts was awarded a National Research Council Fellowship at Harvard University in 1945. He joined the staff of the Massachusetts Institute of Technology (MIT) in 1946, becoming an associate professor by 1950. In 1953, Roberts became a professor of organic chemistry at Caltech. In 1972, he was appointed Institute Professor of Chemistry and in 1988, Institute Professor of Chemistry, Emeritus and Lecturer. From 1980 to 1983 he served Caltech as vice president, provost, and dean of the faculty.

In addition to his many scientific achievements and chemistry lab discoveries, Roberts also was responsible for breaking the longstanding gender barrier at Caltech by sponsoring Dorothy Semenow (PhD '55) to become the Institute's first female doctoral candidate in 1953. Bringing Semenow from MIT to study at Caltech is "clearly the best thing I have done at Caltech in the 60 years I have been here," he says.

Roberts is a recipient of the American Chemical Society Award in Pure Chemistry (1954), the Priestley Medal (1987), the National Medal of Science and  the Welch Award in Chemistry (both in 1990), the Glenn T. Seaborg Medal (1991), the Chemical Pioneer Award of the American Institute of Chemists and the Arthur C. Cope Award of the American Chemical Society (both in 1994), the National Academy of Sciences Award in Chemical Sciences (1999), and the National Academy of Sciences Award for Chemistry in Service to Society (2009).

In 1998, Chemical & Chemical Engineering News named him as one of the 75 most influential chemists in the last 75 years. In 2008, he was elected Fellow of the Royal Society of Chemistry and in 2009, Fellow of the American Chemical Society. He is a member of the American Chemical Society, the American Academy of Arts and Sciences, the American Philosophical Society, and the National Academy of Sciences.

Roberts is the author, with M. C. Caserio, of Basic Principles of Organic Chemistry (1965 and 1977 editions) and has written other textbooks on NMR and Hückel molecular orbital calculations, and more than 500 scientific papers. ACS Books published his autobiography, The Right Place at the Right Time, in 1990.

The AIC is a professional organization dedicated to fostering the advancement of the chemical profession in the United States. Previous AIC Gold Medalists include Alfred Bader, Arnold O. Beckman, Paul Berg, Elizabeth Blackburn, Herbert C. Brown, F. Albert Cotton, Carl Djerassi, Walter Gilbert, Harry B. Gray, Ralph F. Hirschmann, Roald Hoffmann, Robert L. McNeil, Jr., Glenn T. Seaborg, Oliver Smithies, Max Tishler, and George M. Whitesides.

Writer: 
Brian Bell
Frontpage Title: 
Roberts Wins AIC Gold Medal
Listing Title: 
Roberts Wins AIC Gold Medal
Contact: 
Writer: 
Exclude from News Hub: 
Yes
Thursday, September 26, 2013
Ramo Auditorium

Graduate TA Orientation & Teaching Conference

Caltech Seniors Receive Fulbright Fellowships

Three graduating Caltech seniors, Alex Wang, Joy Xie, and Philip Kong, have been selected to receive 2013–2014 Fulbright scholarships to pursue graduate studies abroad.

The Fulbright Program is the U.S. government's premier scholarship program. Set up by Congress in 1946 to foster mutual understanding among nations through educational and cultural exchanges, Fulbright grants enable U.S. students and artists to benefit from unique resources in every corner of the world. Each year more than 800 Americans study or conduct research in more than 140 nations through the Fulbright Program.

"It was a pleasure to work with these students," says Lauren Stolper, director of Fellowships Advising and Study Abroad and Caltech's Fulbright Program advisor. "They each had a well-thought-out research idea based at a host university abroad that will provide the resources and supervision needed to ensure a successful outcome. Our Fulbright Scholars are excellent representatives for the Institute as well as for the U.S.—and part of their role as a Fulbright Scholar is an ambassadorial one."

 

Chemical engineering major Alex Wang, from Dallas, Texas, will be spending a year at Imperial College London in the laboratory of professor Molly Stevens, who specializes in biomedical materials and their application to regenerative medicine. "My topic of study will be how the external stem-cell environment may be able to influence stem-cell behavior and differentiation," Wang says. In particular, he says, "I would be looking at the influence of the protein laminin on differentiation within an artificial hydrogel scaffold. This way, we can look at how these cells can potentially be better controlled in vitro. I chose this topic due to its potential applications in medicine, as well as the opportunity to apply the engineering principles I have learned at Caltech.

"I always wanted to see the UK and experience a brand new culture for an extended period of time. I have never been to Europe," he adds, "so this should be a very eye-opening experience. I am very thankful that Fulbright has given me this honor."

Upon his return, Wang will attend graduate school at MIT, studying biological engineering.

 

Joy Xie, a chemical engineering major from Troy, Michigan, will travel to Switzerland for a research project in bioengineering and protein chemistry, working with Jeffrey Hubbell at the École Polytechnique Fédérale de Lausanne.

"Hubbell has done some very translational work in tissue engineering and drug delivery," Xie explains. The goal of her project is to create protein therapeutics that can be used to induce immune tolerance to certain antigens, such as self-antigens, to help treat autoimmune diseases. "I picked this project because I have always been interested in medicine and how it is possible to combine knowledge from several different fields to create something that has the potential to be used in the medical industry," she says.

"Switzerland seems like an incredibly scenic and exciting place, and I have always wanted to visit it," adds Xie, who will attend Northwestern University to study chemical and biological engineering upon her return to the States. "I'm really grateful for this opportunity and excited to be able to be abroad!"

 

Philip Kong, a biology major from Philadelphia, will be headed this summer to Seoul National University in South Korea to work with professor Sunyoung Kim. Kong, who has been doing immunology research in David Baltimore's lab for the past two years, will be studying how to identify medically meaningful bioactive compounds used in Korea's traditional botanical medicines, with a particular emphasis on screening for activities that control the Th1 and Th2 pathways of the human immune system. Various immune diseases, such as rheumatoid arthritis and allergic diseases, will be considered in the work. "I wanted to try a different type of research than my undergraduate research had been. My new project gives me more opportunity to gain access to patient samples and have more immediate impact when it comes to treating autoimmune diseases like rheumatoid arthritis," says Kong, who plans to go to medical school to pursue an MD/PhD after his year abroad.

"There are many reasons why I wanted to go to Korea," he says, "but the main reason had to do with my project, which involves data from herbal medicine. South Korea is one of the two or three places where the practice of botanical medicine has a rich database regarding botanical medicines, including literature hundreds of years old with lists of plants and their clinical effects and safety profiles. In addition, only specific plants grow in South Korea due to the unique climate of the peninsula."

The Fulbright Program, Kong says, is an "exciting opportunity, and I feel that everyone at Caltech at least deserves a chance to study abroad and enjoy the new air of a different country. Any future Fulbright applicants should not hesitate to contact me if they would like to know more about the program."

Writer: 
Kathy Svitil
Writer: 
Exclude from News Hub: 
No
News Type: 
In Our Community

Frances Arnold Wins Eni Award for Renewable-Energy Work

PASADENA, Calif.—For the second year in a row, a faculty member from the California Institute of Technology (Caltech) has been awarded the Eni Award in Renewable and Non-Conventional Energy. This year, chemical engineer Frances Arnold—who pioneered methods of "directed evolution" for the production and optimization of biological catalysts—has been chosen to receive the distinction, along with her colleague James Liao of UCLA.

Arnold, Caltech's Dick and Barbara Dickinson Professor of Chemical Engineering, Bioengineering and Biochemistry, has shown that mimicking Darwinian evolution in the laboratory is an efficient way to engineer the amino-acid sequence of a protein, endowing it with new capabilities or improving its performance. Arnold and her colleagues have used directed evolution to improve catalysts for making fuels and chemicals from renewable resources.

"There are a lot of creative people working on renewable and non-conventional energy, so it is a huge honor to be selected for this distinction," Arnold says. "This prize recognizes the basic technology we've developed over the years, but especially the application of directed evolution to making things that we currently get from non-renewable hydrocarbons."

The Eni Awards are international prizes that recognize outstanding research and development in the fields of energy and the environment. Eni is an integrated energy company based in Italy. According to the company's website, "The Eni Award was created to develop better use of renewable energy, promote environmental research and encourage new generations of researchers."

A 24-person scientific award committee selects the honorees each year in four categories: New Frontiers of Hydrocarbons, Renewable and Non-Conventional Energy, Protection of the Environment, and Debut in Research. Three additional prizes are awarded for innovative and applied research within Eni, in energy and the environment.

In 2012, Harry A. Atwater, Caltech's Howard Hughes Professor and professor of applied physics and materials science, and director of the Resnick Sustainability Institute, along with his colleague Albert Polman of the Dutch Research Institute AMOLF, was awarded the same Eni Award in Renewable and Non-Conventional Energy, for developing new ultrathin, high-efficiency solar cells.

Of Caltech's back-to-back Eni Awards, Arnold says, "It shows that the renewable-energy research going on at Caltech is world-class. Other places may have much bigger programs, but for impact and accomplishment, the research that the Resnick Institute supports is recognized throughout the world as being at the very top. These groups are making real progress on some of the most important problems we face today."

Arnold, Liao, and the other 2013 awardees will receive their prizes on June 27 at the Presidential Palace in Rome.

Writer: 
Kimm Fesenmaier
Writer: 
Exclude from News Hub: 
Yes

Decision Making and Quality Control in Early Moments of a Protein’s Life

Watson Lecture Preview

Professor of Chemistry Shu-ou Shan studies the gears and springs in the molecular machinery of life. She'll be giving us a guided tour of the cellular assembly line at 8 p.m. on Wednesday, May 22, 2013 in Caltech's Beckman Auditorium. Admission is free.

 

Q: What do you do?

A: I'm a biochemist-slash-biophysicist. I want to understand how our cells' molecular machinery works. These machines are large assemblies of proteins and other molecules that fit together in very specific ways and whose parts move in close coordination to perform the functions of life. I'm particularly interested in understanding how these machines make accurate decisions in the crowded, complex environment inside the cell. These decisions ultimately control what the cell does—will it function correctly, will it turn into a cancer cell, or will it die prematurely?

I'm looking specifically at the decisions that have to be made by various cellular machines every time a new protein molecule is synthesized. For example, there are chaperone machines that help the new protein fold into the right structure. There are protein localizer machines that take the new protein to the right part of the cell—to an organelle, to the cell membrane, or even across the cell membrane, if the protein is a hormone or some other substance the cell intends to secrete. And there are all kinds of enzymes that put chemical tags on the new protein for all sorts of reasons.

We study how these machines work by using a lot of methods developed by chemists and physicists. For example, we can make a protein in a test tube and attach fluorescent dyes to various parts of it. The light from the fluorescence tells us how the protein is interacting with other proteins and how the protein's molecular structure is changing during those interactions. This lets us identify the important interactions that enable the protein to function properly. We do this over and over, putting the dyes in different places and using the data to build a model of how we think the protein works. Then we wipe away the crucial interactions by modifying the protein and see if that disrupts the protein's function in the cell in the ways we predicted.

 

Q: How did you get started on this line of work?

A: I've always believed that when true understanding comes, complexity reduces to simplicity. So the question for me when I was going through middle school and high school was, "What can I do to contribute to that enterprise?"

Then, in high school, I had a revelation. My biology class was studying Mendelian genetics, which are patterns of heredity that you can explain by recombining genes in different ways. Meanwhile, my organic chemistry class was learning about proteins and nucleic acids, and how a few simple principles of base pairing in a molecule of DNA led to a model for how our genetic information is replicated. And I made the connection that all the phenomena of heredity came down to chemical structures I could draw on a piece of paper. They happened because of changing chemical structures, which happened because chemical bonds were made or broken, which happened because the laws of physics drove them. That was an exciting moment.

I majored in chemistry and biochemistry at the University of Maryland, where I also took all the advanced math and physics classes available. They were not required, but I found them very interesting. I went to Stanford for my PhD, where I joined a lab that was trying to find the fundamental principles that explain how enzymes work. It was fantastic training, because we had to think very rigorously in terms of physics and chemistry while still trying to understand the connection to biological function. And at the end, I realized that I still wanted to do biology, so I went on to be a postdoc at a cell biology lab at UC San Francisco. That's where I started working on how proteins make decisions.

 

Q: What gets you really excited about it?

A: Being able to explain very complex and amazing phenomena in the cell at the level of chemical principles. We make a measurement of a molecular action in a test tube and put together a mathematical model that predicts how a certain protein is going to be treated by the cell. Then we go back and test those predictions, see if they match up—not just the trend of the line, but the actual numbers. Those are the divine moments when we really understand something.

My interest in science started with physics and chemistry. Like most physicists, I'm amazed by the beauty and elegance with which the laws of physics explain, and even predict, the phenomena we see around us. I still hold the optimistic belief that ultimately we will explain the complex phenomena of life in terms of simple principles. I guess if science is likened to a craft, I am really a watchmaker. I have to take it down to the very last detail and see how it's all pieced together.

 

Named for the late Caltech professor Earnest C. Watson, who founded the series in 1922, the Watson Lectures present Caltech and JPL researchers describing their work to the public. Many past Watson Lectures are available online at Caltech's iTunes U site.

Writer: 
Douglas Smith
Listing Title: 
Watson Lecture: "Decision Making and Quality Control in Early Moments of a Protein’s Life"
Writer: 
Exclude from News Hub: 
No
News Type: 
In Our Community

Brown, Farley, and Seinfeld Elected to National Academy of Sciences

Based on their distinguished achievements in original research, three Caltech professors—Mike Brown, Ken Farley, and John Seinfeld—are among the 84 members and 21 foreign associates newly elected to the National Academy of Sciences. The announcement was made this week at the 150th annual meeting of the academy in Washington, D.C.

The three new elections bring the number of living Caltech faculty members who belong to the academy to 73, including four foreign associates. In addition, three current members of the Caltech Board of Trustees are academy members.

In total, there are now 2,179 active members and 437 foreign associates of the National Academy of Sciences.

 

Michael E. Brown, the Richard and Barbara Rosenberg Professor and professor of planetary astronomy

Mike Brown is known for discovering and characterizing bodies at the edge of the solar system. In 2005, he discovered a Kuiper-belt object, later named Eris, which is about the same size as Pluto but 27 percent more massive. That finding led to a scientific debate over how to define a planet, and to the eventual demotion of Pluto to "dwarf planet."

Brown received his undergraduate degree from Princeton University in 1987 and did his graduate work at UC Berkeley, completing his PhD in 1994. He came to Caltech as a visiting associate in 1995 and joined the faculty in 1997. Brown became a full professor in 2005 and was named the Rosenberg Professor in 2008.

Brown has won numerous awards for his work, including the 2001 Harold C. Urey Prize from the American Astronomical Society's Division for Planetary Sciences, a Presidential Early Career Award, a Sloan Research Fellowship, and the 2012 Kavli Prize in Astrophysics.

 

Kenneth A. Farley, chair of the Division of Geological and Planetary Sciences and the W. M. Keck Foundation Professor of Geochemistry

Ken Farley is recognized for his studies of the noble gases and what their concentrations in marine sediments, rocks, minerals, and seawater can tell us about geochemical processes and the timescales over which these processes have operated. He is also currently a participating scientist on NASA's Mars Science Laboratory rover mission.

Farley received a BS from Yale University in 1986 and a PhD from UC San Diego in 1991. He joined the Caltech faculty in 1993 and was appointed professor in 1998. Farley was named the Keck Foundation Professor in 2003, the same year he served as director of the Tectonics Observatory. He became division chair in 2004.

His distinctions include the 1999 James B. Macelwane Medal of the American Geophysical Union, the 2000 National Academy of Science Award for Initiatives in Research, and the 2008 Arthur L. Day Medal from the Geological Society of America, and he was named a 2013 Geochemical Fellow by the Geochemical Society and the European Association of Geochemistry.

 

John H. Seinfeld, the Louis E. Nohl Professor and professor of chemical engineering

John Seinfeld's work has greatly improved our understanding of the origin, chemistry, and evolution of particles, or aerosols, in the atmosphere. He has revealed the role of organic species in aerosols and the process by which vapor molecules become incorporated into particles. Today, his work continues to focus on large questions such as the effects of aerosols on cloud formation and Earth's climate.

Seinfeld received his BS from the University of Rochester in 1964 and his PhD from Princeton University in 1967. He joined the faculty at Caltech that same year, becoming a full professor in 1974 and the Nohl Professor in 1979. He served as executive officer for chemical engineering from 1974 until 1990 and was chair of the Division of Engineering and Applied Science from 1990 until 2000.

Seinfeld is a member of the National Academy of Engineering and a fellow of the American Academy of Arts and Sciences. Among other distinctions, he won the Tyler Prize for Environmental Achievement in 2012, the American Chemical Society's Award for Creative Advances in Environmental Science and Technology in 1993, the Fuchs Award in 1998, the Nevada Medal in 2001, and the Stodola Medal from the Swiss Federal Institute of Technology in 2008. He has also received honorary doctorates from the University of Patras, Carnegie Mellon University, and Clarkson University.

 

The National Academy of Sciences is a private, nonprofit honorific society of distinguished scholars engaged in scientific and engineering research, dedicated to the furthering of science and technology and to their use for the general welfare. Established in 1863, the National Academy of Sciences has served to "investigate, examine, experiment, and report upon any subject of science or art" whenever called upon to do so by any department of the government.

For more information about the academy, or for the full list of newly elected members, visit www.nationalacademies.orgFor an extensive list of Caltech awards and honors, visit www.caltech.edu/content/awards-honors.

Writer: 
Kimm Fesenmaier
Writer: 
Exclude from News Hub: 
No
News Type: 
In Our Community

Fifty Years of Clearing the Skies

A Milestone in Environmental Science

Ringed by mountains and capped by a temperature inversion that traps bad air, Los Angeles has had bouts of smog since the turn of the 20th century. An outbreak in 1903 rendered the skies so dark that many people mistook it for a solar eclipse. Angelenos might now be living in a state of perpetual midnight—assuming we could live here at all—were it not for the work of Caltech Professor of Bio-organic Chemistry Arie Jan Haagen-Smit. How he did it is told here largely in his own words, excerpted from Caltech's Engineering & Science magazine between 1950 and 1962. (See "Related Links" for the original articles.)

Old timers, which in California means people who have lived here some 25 years, will remember the invigorating atmosphere of Los Angeles, the wonderful view of the mountains, and the towns surrounded by orange groves. Although there were some badly polluted industrial areas, it was possible to ignore them and live in more pleasant locations, especially the valleys . . . Just 20 years ago, the community was disagreeably surprised when the atmosphere was filled with a foreign substance that produced a strong irritation of the eyes. Fortunately, this was a passing interlude which ended with the closing up of a wartime synthetic rubber plant. (November 1962)

Alas, the "interlude" was an illusion. In the years following World War II, visibility often fell to a few blocks. The watery-eyed citizenry established the Los Angeles County Air Pollution Control District (LACAPCD) in 1947, the first such body in the nation. The obvious culprits—smoke-belching power plants, oil refineries, steel mills, and the like—were quickly regulated, yet the problem persisted. Worse, this smog was fundamentally different from air pollution elsewhere—the yellow, sulfur-dioxide-laced smog that killed 20 people in the Pennsylvania steel town of Donora in 1948, for example, or London's infamous pitch-black "pea-soupers," where the burning of low-grade, sulfur-rich coal added soot to the SO2. (The Great Smog of 1952 would carry off some 4,000 souls in four days.) By contrast, L.A.'s smog was brown and had an acrid odor all its own.

Haagen-Smit had honed his detective skills isolating and identifying the trace compounds responsible for the flavors of pineapples and fine wines, and in 1948 he began to turn his attention to smog.

Chemically, the most characteristic aspect of smog is its strong oxidizing action . . . The amount of oxidant can readily be determined through a quantitative measurement of iodine liberated from potassium iodide solution, or of the red color formed in the oxidation of phenolphthalin to the well-known acid-base indicator, phenolphthalein. To demonstrate these effects, it is only necessary to bubble a few liters of smog air through the colorless solutions. (December 1954)

His chief suspect was ozone, a highly reactive form of oxygen widely used as a bleach and a disinfectant. It's easy to make—a spark will suffice—and it's responsible for that crisp "blue" odor produced by an overloaded electric motor. But there was a problem:

During severe smog attacks, ozone concentrations of 0.5 ppm [parts per million], twenty times higher than in [clean] country air, have been measured. From such analyses the quantity of ozone present in the [Los Angeles] basin at that time is calculated to be about 500 tons.

Since ozone is subject to a continuous destruction in competition with its formation, we can estimate that several thousand tons of ozone are formed during a smog day. It is obvious that industrial sources or occasional electrical discharges do not release such tremendous quantities of ozone. (December 1954)

If ozone really was to blame, where was it coming from? An extraordinary challenge lay ahead:

The analysis of air contaminants has some special features, due to the minute amounts present in a large volume of air. The state in which these pollutants are present—as gases, liquids and solid particles of greatly different sizes—presents additional difficulties. The small particles of less than one micron diameter do not settle out, but are in a stable suspension and form so-called aerosols.

The analytical chemist has devoted a great deal of effort to devising methods for the collection of this heterogeneous material. Most of these methods are based on the principle that the particles are given enough speed to collide with each other or with collecting surfaces . . . A sample of Los Angeles' air shows numerous oily droplets of a size smaller than 0.5 micron, as well as crystalline deposits of metals and salts . . . When air is passed through a filter paper, the paper takes on a grey appearance, and extraction with organic solvents gives an oily material. (December 1950)

Haagen-Smit suspected that this oily material, a complex brew of organic acids and other partially oxidized hydrocarbons, was smog's secret ingredient. In 1950, he took a one-year leave of absence from Caltech to prove it, working full-time in a specially equipped lab set up for him by the LACAPCD. By the end of the year, he had done so.

Through investigations initiated at Caltech, we know that the main source of this smog is due to the release of two types of material. One is organic material—mostly hydrocarbons from gasoline—and the other is a mixture of oxides of nitrogen. Each one of these emissions by itself would be hardly noticed. However, in the presence of sunlight, a reaction occurs, resulting in products which give rise to the typical smog symptoms. The photochemical oxidation is initiated by the dissociation of NO2 into NO and atomic oxygen. This reactive oxygen attacks organic material, resulting in the formation of ozone and various oxidation products . . . The oxidation reactions are generally accompanied by haze or aerosol formation, and this combination aggravates the nuisance effects of the individual components of the smog complex. (November 1962)

Professor of Plant Physiology Frits Went was also on the case. Went ran Caltech's Earhart Plant Research Laboratory, which he proudly called the "phytotron," by analogy to the various "trons" operated by particle physicists. (Phyton is the Greek word for plant.) "Caltech's plant physiologists happen to believe that the phytotron is as marvellously complicated as any of the highly-touted 'atom-smashing' machines," Went wrote in E&S in 1949. "[It] is the first laboratory in the world in which plants can be grown under every possible climatic condition. Light, temperature, humidity, gas content of the air, wind, rain, and fog—all these factors can be simultaneously and independently controlled. The laboratory can create Sacramento Valley climate in one room and New England climate in another." Most of Los Angeles was still orchards and fields instead of tract houses, and the smog was hurting the produce. Went, the LACAPCD, and the UC Riverside agricultural station tested five particularly sensitive crops in the phytotron, Haagen-Smit wrote.

The smog indicator plants include spinach, sugar beet, endive, alfalfa and oats. The symptoms on the first three species are mainly silvering or bronzing of the underside of the leaf, whereas alfalfa and oats show bleaching effects. Some fifty compounds possibly present in the air were tested on their ability to cause smog damage—without success. However, when the reaction products of ozone with unsaturated hydrocarbons were tried, typical smog damage resulted. (December 1950)

And yet a third set of experiments was under way. Rubber tires were rotting from the smog at an alarming rate, cracking as they flexed while rolling along the road. Charles E. Bradley, a research associate in biology, turned this distressing development into a cheap and effective analytical tool by cutting rubber bands by the boxful into short segments. The segments—folded double, secured with a twist of wire, and set outside—would start to fall apart almost before one could close the window. "During severe smog initial cracking appears in about four minutes, as compared to an hour or more required on smog-free days, or at night," Haagen-Smit wrote in the December 1954 E&S.

The conclusion that airborne gasoline and nitrogen oxides (another chief constituent of automobile exhaust) were to blame for smog was not well received by the oil refineries, who hired their own expert to prove him wrong. Abe Zarem (MS '40, PhD '44), the manager and chairman of physics research for the Stanford Research Institute, opined that stratospheric ozone seeping down through the inversion layer was to blame. But seeing (or smelling) is believing, so Haagen-Smit fought back by giving public lectures in which he would whip up flasks full of artificial smog before the audience's eyes, which would soon be watering—especially if they were seated in the first few rows. By the end of his talk, the smog would fill the hall, and he became known throughout the Southland as Arie Haagen-Smog.

By 1954, he and Frits Went had carried the day.

[Plant] fumigations with the photochemical oxidation products of gasoline and nitrogen dioxide (NO2) was the basis of one of the most convincing arguments for the control of hydrocarbons by the oil industry. (December 1954)

It probably didn't hurt that an outbreak that October closed schools and shuttered factories for most of the month, and that angry voters were wearing gas masks to protest meetings. By then, there were some two million cars on the road in the metropolitan area, spewing a thousand tons of hydrocarbons daily.

Incomplete combustion of gasoline allows unburned and partially burned fuel to escape from the tailpipe. Seepage of gasoline, even in new cars, past piston rings into the crankcase, is responsible for 'blowby' or crankcase vent losses. Evaporation from carburetor and fuel tank are substantial contributions, especially on hot days. (November 1962)

Haagen-Smit was a founding member of California's Motor Vehicle Pollution Control Board, established in 1960. One of the board's first projects was testing positive crankcase ventilation (PCV) systems, which sucked the blown-by hydrocarbons out of the crankcase and recirculated them through the engine to be burned on the second pass. PCV systems were mandated on all new cars sold in California as of 1963. The blowby problem was thus easily solved—but, as Haagen-Smit noted in that same article, it was only the second-largest source, representing about 30 percent of the escaping hydrocarbons.

The preferred method of control of the tailpipe hydrocarbon emission is a better combustion in the engine itself. (The automobile industry has predicted the appearance of more efficiently burning engines in 1965. It is not known how efficient these will be, nor has it been revealed whether there will be an increase or decrease of oxides of nitrogen.) Other approaches to the control of the tailpipe gases involve completing the combustion in muffler-type afterburners. One type relies on the ignition of gases with a sparkplug or pilot-burner; the second type passes the gases through a catalyst bed which burns the gases at a lower temperature than is possible with the direct-flame burners. (November 1962)

Installing an afterburner in the muffler has some drawbacks, not the least of which is that the notion of tooling around town with an open flame under the floorboards might give some people the willies. Instead, catalytic converters became required equipment on California cars in 1975.

In 1968, the Motor Vehicle Pollution Control Board became the California Air Resources Board, with Haagen-Smit as its chair. He was a member of the 1969 President's Task Force on Air Pollution, and the standards he helped those two bodies develop would eventually be adopted by the Environmental Protection Agency, established in 1970—the year that also saw the first celebration of Earth Day. It was also the year when ozone levels in the Los Angeles basin peaked at 0.58 parts per million, nearly five times in excess of the 0.12 parts per million that the EPA would declare to be safe for human health. This reading even exceeded the 0.5 ppm that Haagen-Smit had measured back in 1954, but it was a triumph nonetheless—the number of cars in L.A. had doubled, yet the smog was little worse than it had always been. That was the year we turned the corner, in fact, and our ozone levels have been dropping ever since—despite the continued influx of cars and people to the region.

Haagen-Smit retired from Caltech in 1971 as the skies began to clear, but continued to lead the fight for clean air until his death in 1977—of lung cancer, ironically, after a lifetime of cigarettes. Today, his intellectual heirs, including professors Richard Flagan, Mitchio Okumura, John Seinfeld, and Paul Wennberg, use analytical instruments descended from ones Haagen-Smit would have recognized and computer models sophisticated beyond his wildest dreams to carry the torch—a clean-burning one, of course—forward.

Writer: 
Douglas Smith
Writer: 
Exclude from News Hub: 
No

Picking Apart Photosynthesis

New insights from Caltech chemists could lead to better catalysts for water splitting

PASADENA, Calif.—Chemists at the California Institute of Technology (Caltech) and the Lawrence Berkeley National Laboratory believe they can now explain one of the remaining mysteries of photosynthesis, the chemical process by which plants convert sunlight into usable energy and generate the oxygen that we breathe. The finding suggests a new way of approaching the design of catalysts that drive the water-splitting reactions of artificial photosynthesis.

"If we want to make systems that can do artificial photosynthesis, it's important that we understand how the system found in nature functions," says Theodor Agapie, an assistant professor of chemistry at Caltech and principal investigator on a paper in the journal Nature Chemistry that describes the new results.

One of the key pieces of biological machinery that enables photosynthesis is a conglomeration of proteins and pigments known as photosystem II. Within that system lies a small cluster of atoms, called the oxygen-evolving complex, where water molecules are split and molecular oxygen is made. Although this oxygen-producing process has been studied extensively, the role that various parts of the cluster play has remained unclear. 

The oxygen-evolving complex performs a reaction that requires the transfer of electrons, making it an example of what is known as a redox, or oxidation-reduction, reaction. The cluster can be described as a "mixed-metal cluster" because in addition to oxygen, it includes two types of metals—one that is redox active, or capable of participating in the transfer of electrons (in this case, manganese), and one that is redox inactive (calcium).

"Since calcium is redox inactive, people have long wondered what role it might play in this cluster," Agapie says.

It has been difficult to solve that mystery in large part because the oxygen-evolving complex is just a cog in the much larger machine that is photosystem II; it is hard to study the smaller piece because there is so much going on with the whole. To get around this, Agapie's graduate student Emily Tsui prepared a series of compounds that are structurally related to the oxygen-evolving complex. She built upon an organic scaffold in a stepwise fashion, first adding three manganese centers and then attaching a fourth metal. By varying that fourth metal to be calcium and then different redox-inactive metals, such as strontium, sodium, yttrium, and zinc, Tsui was able to compare the effects of the metals on the chemical properties of the compound.

"When making mixed-metal clusters, researchers usually mix simple chemical precursors and hope the metals will self-assemble in desired structures," Tsui says. "That makes it hard to control the product. By preparing these clusters in a much more methodical way, we've been able to get just the right structures."

It turns out that the redox-inactive metals affect the way electrons are transferred in such systems. To make molecular oxygen, the manganese atoms must activate the oxygen atoms connected to the metals in the complex. In order to do that, the manganese atoms must first transfer away several electrons. Redox-inactive metals that tug more strongly on the electrons of the oxygen atoms make it more difficult for manganese to do this. But calcium does not draw electrons strongly toward itself. Therefore, it allows the manganese atoms to transfer away electrons and activate the oxygen atoms that go on to make molecular oxygen.

A number of the catalysts that are currently being developed to drive artificial photosynthesis are mixed-metal oxide catalysts. It has again been unclear what role the redox-inactive metals in these mixed catalysts play. The new findings suggest that the redox-inactive metals affect the way the electrons are transferred. "If you pick the right redox-inactive metal, you can tune the reduction potential to bring the reaction to the range where it is favorable," Agapie says. "That means we now have a more rational way of thinking about how to design these sorts of catalysts because we know how much the redox-inactive metal affects the redox chemistry."

The paper in Nature Chemistry is titled "Redox-inactive metals modulate the reduction potential in heterometallic manganese-oxido clusters." Along with Agapie and Tsui, Rosalie Tran and Junko Yano of the Lawrence Berkeley National Laboratory are also coauthors. The work was supported by the Searle Scholars Program, an NSF CAREER award, and the NSF Graduate Research Fellowship Program. X-ray spectroscopy work was supported by the NIH and the DOE Office of Basic Energy Sciences. Synchrotron facilities were provided by the Stanford Synchrotron Radiation Lightsource, operated by the DOE Office of Biological and Environmental Research. 

Writer: 
Kimm Fesenmaier
Writer: 
Exclude from News Hub: 
No
News Type: 
Research News
Monday, April 1, 2013
Center for Student Services, 3rd Floor, Brennan Conference Room

Head TA Network Kick-off Meeting & Happy Hour

bbell2's picture

Theodor Agapie Named Cottrell Scholar

Research Corporation for Science Advancement (RCSA) has named Theodor Agapie, an assistant professor of chemistry at Caltech, a 2013 Cottrell Scholar.

The Cottrell Scholar Awards were instituted by RCSA in 1994 to recognize early-career individuals for innovative research and teaching excellence. The awards are named in honor of scientist, inventor, and philanthropist Frederick Gardner Cottrell who, in 1912, founded the organization that came to be known as RCSA.

"I am honored to have been selected as a Cottrell Scholar by RCSA," says Agapie. "I am grateful to my team of researchers and the greater Caltech community for a rewarding and stimulating environment in which to do science."

Using the natural world as a source of inspiration, Agapie's research group studies and develops molecular systems to solve problems related to energy, materials, and health. In addition to his lab-based research, Agapie actively works to bring together graduate, undergraduate, and high school students through an outreach program that includes career mentoring, designing new experiments, and organized visits to the Caltech campus.

Agapie, a native of Romania, received his bachelor's degree from MIT in 2001 and his PhD from Caltech in 2007. He has been an assistant professor at Caltech since early 2009. Since joining Caltech's faculty, Agapie has been named a Searle Scholar, a Sloan Research Fellow, and a recipient of a National Science Foundation CAREER Award, and he has received the Award in Pure Chemistry from the American Chemical Society.

 

 

 

 

Writer: 
Brian Bell
Frontpage Title: 
Agapie Named Cottrell Scholar
Listing Title: 
Agapie Named Cottrell Scholar
Contact: 
Writer: 
Exclude from News Hub: 
Yes

Pages

Subscribe to RSS - CCE