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News from the Physical Sciences

New Tool Allows Scientists to Visualize ‘Nanoscale’ Processes

Chemists at UC San Diego have developed a new tool that allows scientists for the first time to see, at the scale of five billionths of a meter, “nanoscale” mixing processes occurring in liquids.

“Being able to look at nanoscale chemical gradients and reactions as they take place is just such a fundamental tool in biology, chemistry and all of material science,” said Nathan Gianneschi, a professor of chemistry and biochemistry who headed the team that detailed the development in a paper in this week’s issue of the journal Microscopy and Microanalysis. “With this new tool, we’ll be able to look at the kinetics and dynamics of chemical interactions that we’ve never been able to see before.”

‘Adaptive Protein Crystal’ Could Form New Kind of Protective Material

Chemists at UC San Diego have created an “adaptive protein crystal” with a counterintuitive and potentially useful property: When stretched in one direction, the material thickens in the perpendicular direction, rather than thinning as familiar materials do. And when squeezed in one dimension, it shrinks in the other rather than expanding, and gets denser in the process.

This strange behavior could prove useful for the sole of a running shoe that thickens for greater shock absorption as heel collides with pavement, for example, or to construct body armor that strengthens when a bullet strikes.

How DNA Can Take on the Properties of Sand or Toothpaste

When does DNA behave like sand or toothpaste?

When the genetic material is so densely packed within a virus, it can behave like grains of sand or toothpaste in a tube.

That’s essentially what biophysicists at UC San Diego discovered when they began closely examining the physical properties of DNA jammed inside viruses.

Three Earth-Sized Planets Found Orbiting a Tiny Nearby Star

An international team of astronomers, including UC San Diego astrophysicists, has discovered three Earth-sized planets orbiting near the “habitable zone” of an ultracool dwarf star, the first planets ever discovered around such a tiny and dim star.

The discovery is detailed in a paper published this week in the journal Nature. The planets are so close to Earth—only 40 light years away—that astronomers should eventually be able to study in greater detail the composition of each of the planets and their atmospheres as well as look for chemical signals of life.

In Memoriam: Walter Kohn 1923-2016

walterkohnWalter Kohn, one of the founding faculty members of the Department of Physics at UC San Diego who received the 1998 Nobel Prize in Chemistry while a professor at UC Santa Barbara, died at his home in Santa Barbara of cancer on April 19. He was 93.

Kohn came to the newly founded UC San Diego campus as a physics professor in 1960 after working for a decade at Carnegie Mellon University. He served as chair of physics from 1961 to 1963 and left the La Jolla campus in 1979 to accept a position at UC Santa Barbara as the founding director of what is now called the Kavli Institute for Theoretical Physics. He remained at UC Santa Barbara as an emeritus professor and research professor until his death.

Supported by the National Science Foundation, the Kavli Institute for Theoretical Physics brings leading scientists from around the world to work on major problems in theoretical physics and related fields. In 1994, the building that houses the institute was named Kohn Hall in his honor.

A condensed matter theorist, Kohn made seminal contributions to the understanding of the electronic structure of materials and played the leading role in the development of the density functional theory, which has revolutionized scientists' approach to the electronic structure of atoms, molecules and solid materials in physics, chemistry and materials science.

He also made major contributions to the physics of semiconductors, superconductivity, surface physics and catalysis. A member of the National Academy of Sciences, Kohn was awarded the National Medal of Science in 1988 and the Niels Bohr gold medal from the United Nations in 1998.

Benjamin Grinstein, chair of UC San Diego’s Department of Physics, said Kohn had one of the most profound impacts on the field of physics over the past century.

“A study of citations from all Physical Review journals for the 110-year period 1893 until 2003 shows the paper by Kohn and our own Lu Sham (an emeritus physics professor at UC San Diego) to be the top cited paper and the one ranked highest in citation impact, and the paper by Hohenberg and Kohn as the second most cited paper and ranked second in citation impact,” he added. “In fact, Walter authored five of the 100 papers with highest citation impact.”

More specifically, said Grinstein, “Kohn started work on density functional theory during a visit with Pierre Hohenberg to the École Normale Supérieure in Paris. Then Walter and Lu expanded on that work to produce the now famous Kohn-Sham equations. The latter is the standard work horse of modern materials science, and even used in quantum theories of plasmas.”

On March 31, the UC San Diego Physics Department held its annual Memorial Lecture on a topic chosen to honor the 50th anniversary of the publication of the Kohn-Sham paper

In Memoriam: Ami E. Berkowitz


Ami E. Berkowitz, a research professor in UC San Diego’s Department of Physics and Center for Memory and Recording Research, died on March 31, 2016 of heart failure. He was 89.

Berkowitz received his Ph.D. in physics from the University of Pennsylvania in 1953. He was employed by the Franklin Institute Laboratories in Philadelphia from 1947 to 1960 where he was manager of the Magnetism and Thermoelectricity Division. He was with IBM from 1960 to 1968, initially at the Research Laboratory at Yorktown Heights, NY, and then as manager of the Materials Branch at the Components Division in Burlington, VT. From 1968 to 1986, Berkowitz was at the General Electric R&D Center in Schenectady, NY. There, he was active in electron beam addressed memories, thermomagnetic recording, magnetic tagging, magnetic printing, magnetic surface phenomena, amorphous and crystalline particles, and the development of spark erosion method for particle production.

In 1986, he came to UC San Diego as a professor in the Physics Department with an endowed chair, and to CMRR to establish the materials group. After retiring, he continued as a research professor at CMRR and the Physics Department. Berkowitz published extensively in the scientific and patent literature and with E. Kneller co-edited "Magnetism and Metallurgy," published by Academic Press.  He also gave many invited talks, and was been twice appointed a Distinguished Lecturer for the IEEE Magnetics Society and, in 1997, he was elected a Fellow of the American Physical Society.

He is survived by his wife, Alice Berkowitz; two sons, Barney and Jon Berkowitz; daughter Dana Berkowitz; and three grandchildren

Math professor named fellow of prestigious society

Michael Holst, a professor of mathematics and physics has been named a 2016 Fellow of the Society of Industrial and Applied Mathematics. Holst, who holds a UC San Diego Chancellor’s Associates Endowed Chair, is being honored “for contributions to computational biology, numerical relativity and scientific computation.” He is an author and reviewer and has served on many of the editorial boards for the society’s journals.

Alice C. Tyler Perpetual Trust Gives $125,000 for Sally Ride Scholarship

Long after her first flight into space, the late astronaut Sally Ride remained dedicated to science education and protecting the environment. Now, a new scholarship at the University of California, San Diego will help continue her legacy by supporting the next generation of Earth’s stewards. The Alice C. Tyler Perpetual Trust has made a $125,000 gift to establish the Alice C. Tyler Perpetual Trust Endowed Scholarship for the Advancement of Women in Science in Honor of Dr. Sally Ride.  

Structures associated with memory sprout in response to drug candidates

Chemists at UC San Diego have designed a set of molecules that promote microscopic, anatomical changes in neurons associated with the formation and retention of memories.

These drug candidates also prevent deterioration of the same neuronal structures in the presence of amyloid-beta, a protein fragment that accumulates in the brains of people with Alzheimer's disease.

Breathing is a rhythm for life, and more

Respiration is more than just an essential rhythm for life. A new study by Martin Deschênes and David Kleinfeld, a professor of physics, has found that rhythmic neural patterns that control breathing also coordinate movements of muscles on the mouth and face that serve a variety of sensory, ingestive and social behaviors.

Circuits that control breathing are essential to coordinating other motor activity, such as whisking and sniffing, across the right and left sides of the body, they report in the journal Neuron, and inhibition by that same breathing circuit controls other motions by rhythmic suppression. 

Alice C. Tyler Perpetual Trust Gives $125,000 for Sally Ride Scholarship

Long after her first flight into space, the late astronaut Sally Ride remained dedicated to science education and protecting the environment. Now, a new scholarship at the University of California, San Diego will help continue her legacy by supporting the next generation of Earth’s stewards. The Alice C. Tyler Perpetual Trust has made a $125,000 gift to establish the Alice C. Tyler Perpetual Trust Endowed Scholarship for the Advancement of Women in Science in Honor of Dr. Sally Ride.

How Hydra opens its mouth

A team of biologists and physicists at UC San Diego has uncovered in detail the dynamic process that allows the multi-tentacle Hydra, a tiny freshwater animal distantly related to the sea anemone, to open and close its mouth.

The researchers report their findings in the current issue of Biophysical Journal. They say their discovery not only solves a long-standing puzzle of how Hydra feeds, but also enabled them to address a complex phenomenon in a living animal using relatively simple physics.

Clear view

Clear images of minute packages meant to shield healthy cells from potent anti-cancer drugs have helped researchers evaluate a promising of new approach to chemotherapy. To protect healthy tissues from the harm of chemotherapy, researchers wrapped drug particles in protective membranes, then turned to a team led by Elizabeth Villa to see how well their procedure worked. Reika Watanabe used cryoEM to capture images of the particles to reconstruct the structures in three dimensions. Read more.

Space dust

Karin Sandstrom, assistant professor of physics, studies the interstellar medium - the dust and gas in galaxies and between stars, and especially how ultraviolet light interacts with soot-like polycyclic aromatic hydrocarbons.

That, she says, is key to everything - how stars (and planets) form, how galaxies evolve, and perhaps how life emerged. Watch video.

Molecular Avalanche

Palladium, unlike any other element, takes up hydrogen at room temperature and pressure.

Oleg Shpyrko's group and colleagues have determined how uptake of hydrogen changes the atomic structure of the palladium through an 'avalanche' of strain and identified key properties of how this form of hydrogen storage could work in the future. They report their work in Nature Communications.

Star role models

Shelley Wright, Quinn Konopacky and Karin SandstromShelley Wright, Quinn Konopacky and Karin Sandstrom, astrophysicists recently hired as assistant professors of physics in the Division of Physical Sciences and the Center for Astrophysics and Space Sciences, are giving humanity a view of the universe as it’s never been seen before.

They’ve joined four other female physics professors—Alison Coil, Eva-Maria Collins, Olga Dudko and Elizabeth Jenkins—as important mentors and role models. Read more.

Rising stars

Emily PayneAt a time when women remain underrepresented in the sciences and a student can still complete a physics degree without taking a class in her major led by a female professor, UC San Diego welcomed nearly 200 students to a conference for undergraduate women in physics.

"We wanted to provide an opportunity to make connections," said Emily Payne, a fourth-year physics major who led the local organizing committee. "What I mean by that is not so much networking to find jobs, but to create a community." Read more.

Inventions for a safer, healthier world recognized

Michael Sailor, a leader in silicon nanotechnology who holds 26 U.S. patents, has been elected a Fellow of the National Academy of Inventors. Sailor, Distinguished Professor of Chemistry and Biochemisty, carefully structures porous silicon on a nanometer scale to address such divergent goals as the safer, targeted delivery of powerful therapeutics to rechargeable batteries with higher capacity and longer life. Learn more.

Precise constraints on primordial magnetism

The POLARBEAR experiment reports the most precise constraint of primordial magnetic fields measured to date, a window onto the some of the fundamental physics of the early universe. The paper, publisehd in the journal Physical Review D, has been chosen as an "Editor's Suggesion."

Learn more about physics professor Brian Keating's group's quest to unveil the state of the universe at the beginning of time here.

Why ferment when there's plenty of oxygen?

Fermentation is a great way to generate energy in the absence of oxygen, but it's much less efficient than aerobic respiration and generates considerable metabolic waste, such as lactic acid. Yet some bacteria, fungi and other fast-growing cells use this form of anaerobic respiration even when oxygen is plentiful, and for a long time biologists have wondered why these organisms use such an apparently wasteful approach.

A new accounting of the energy budget by a team of physicists and biologists led by Terry Hwa found that when you add the metabolic cost of synthesizing the enzymes and other required cellular apparatus to the value of the sugars in and energy out, fermentation makes sense for fast-growing cells, including cancers. More>>

Physicists predict mechanics of touch

A sense of touch mediates much of our interaction with the world beyond our skin.  By turning the mechanical energy of things that impinge on the skin into electrical signals within the nervous system, a variety of structures sense events that range from the faint brush of a breeze to the sharp pain of a cut.

Massimo Vergassola, a theoretical physicist with an interest in how organisms use sensory systems to navigate their world, wondered what physical system might underlie a particularly intriguing neural response to touch in C. elegans. He and graduate student Alessandro Sanzeni developed a physical model that accounted for experimental observations and predicted additional properties of this sensory system. More>>

Mathematician honored for major contributions to algebraic geometry

James McKernan, professor of mathematics, will share the 2016 E.H. Moore Research Article Prize given by the American Mathematical Society for work cited as a "watershed" in algebraic geometry, a branch of mathematics that investigates connections between numbers and shapes. With a pair of papers published in the Journal of the AMS in 2010, McKernan and co-authors Caucher Birkar of the University of Cambridge, Paolo Cascini of Imperial College London, and Christopher Hacon of the University of Utah made a major stride in advancing the "minimal model program," which seeks a way of classifying algebraic varieties by finding representations that are in some sense the simplest.

Brushing up peptides boosts their potential as drugs

Peptides promise to be useful drugs, but they're too easily digested and can’t get into cells without help.

Now Angela Blum and Jaquelin Kammeyer, working with chemistry professor Nathan Gianneschi, show that rearranging peptides into dense brushes can protect them from digestion and ease them into cells without changing their biological function. Read more.

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