Tag Archives: Paul Alivisatos

Philosophy and science in Tokyo, Japan from Dec. 1-2, 2022

I have not seen a more timely and à propos overview for a meeting/conference/congress that this one for Tokyo Forum 2022 (hosted by the University of Tokyo and South Korea’s Chey Institute for Advanced Studies),

Dialogue between Philosophy and Science: In a World Facing War, Pandemic, and Climate Change

In the face of war, a pandemic, and climate change, we cannot repeat the history of the last century, in which our ancestors headed down the road to division, global conflict, and environmental destruction.

How can we live more fully and how do we find a new common understanding about what our society should be? Tokyo Forum 2022 will tackle these questions through a series of in-depth dialogues between philosophy and science. The dialogues will weave together the latest findings and deep contemplation, and explore paths that could lead us to viable answers and solutions.

Philosophy of the 21st century must contribute to the construction of a new universality based on locality and diversity. It should be a universality that is open to co-existing with other non-human elements, such as ecosystems and nature, while severely criticizing the understanding of history that unreflectively identifies anthropocentrism with universality.

Science in the 21st century also needs to dispense with its overarching aura of supremacy and lack of self-criticism. There is a need for scientists to make efforts to demarcate their own limits. This also means reexamining what ethics means for science.

Tokyo Forum 2022 will offer multifaceted dialogues between philosophers, scientists, and scholars from various fields of study on the state and humanity in the 21st century, with a view to imagining and proposing a vision of the society we need.

Here are some details about the hybrid event from a November 4, 2022 University of Tokyo press release on EurekAlert,

The University of Tokyo and South Korea’s Chey Institute for Advanced Studies will host Tokyo Forum 2022 from Dec. 1-2, 2022. Under this year’s theme “Dialogue between Philosophy and Science,” the annual symposium will bring together philosophers, scientists and scholars in various fields from around the world for multifaceted dialogues on humanity and the state in the 21st century, while envisioning the society we need.

The event is free and open to the public, and will be held both on site at Yasuda Auditorium of the University of Tokyo and online via livestream. [emphases mine]

Keynote speakers lined up for the first day of the two-day symposium are former U.N. Secretary-General Ban Ki-moon, University of Chicago President Paul Alivisatos and Mariko Hasegawa, president of the Graduate University for Advanced Studies in Japan.

Other featured speakers on the event’s opening day include renowned modern thinker and author Professor Markus Gabriel of the University of Bonn, and physicist Hirosi Ooguri, director of the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo and professor at the California Institute of Technology, who are scheduled to participate in the high-level discussion on the dialogue between philosophy and science.

Columbia University Professor Jeffrey Sachs will take part in a panel discussion, also on Day 1, on tackling global environmental issues with stewardship of the global commons — the stable and resilient Earth system that sustains our lives — as a global common value.

The four panel discussions slated for Day 2 will cover the role of world philosophy in addressing the problems of a globalized world; transformative change for a sustainable future by understanding the diverse values of nature and its contributions to people; the current and future impacts of autonomous robots on society; and finding collective solutions and universal values to pursue equitable and sustainable futures for humanity by looking at interconnections among various fields of inquiry.

Opening remarks will be delivered by University of Tokyo President Teruo Fujii and South Korea’s SK Group Chairman Chey Tae-won, on Day 1. Fujii and Chey Institute President Park In-kook will make closing remarks following the wrap-up session on the second and final day.

Tokyo Forum with its overarching theme “Shaping the Future” is held annually since 2019 to stimulate discussions on finding the best ideas for shaping the world and humanity in the face of complex situations where the conventional wisdom can no longer provide answers.

For more information about the program and speakers of Tokyo Forum 2022, visit the event website and social media accounts:

Website: https://www.tokyoforum.tc.u-tokyo.ac.jp/en/index.html

Twitter: https://twitter.com/UTokyo_forum

Facebook: https://www.facebook.com/UTokyo.tokyo.forum/

To register, fill out the registration form on the Tokyo Forum 2022 website (registration is free but required [emphasis mine] to attend the event): https://www.tokyo-forum-form.com/apply/audiences/en

I’m not sure how they are handling languages. I’m guessing that people are speaking in the language they choose and translations (subtitles or dubbing) are available. For anyone who may have difficulty attending due to timezone issues, there are archives for previous Tokyo Forums. Presumably 2022 will be added at some point in the future.

SINGLE (3D Structure Identification of Nanoparticles by Graphene Liquid Cell Electron Microscopy) and the 3D structures of two individual platinum nanoparticles in solution

It seems to me there’s been an explosion of new imaging techniques lately. This one from the Lawrence Berkelely National Laboratory is all about imaging colloidal nanoparticles (nanoparticles in solution), from a July 20, 2015 news item on Azonano,

Just as proteins are one of the basic building blocks of biology, nanoparticles can serve as the basic building blocks for next generation materials. In keeping with this parallel between biology and nanotechnology, a proven technique for determining the three dimensional structures of individual proteins has been adapted to determine the 3D structures of individual nanoparticles in solution.

A multi-institutional team of researchers led by the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab), has developed a new technique called “SINGLE” that provides the first atomic-scale images of colloidal nanoparticles. SINGLE, which stands for 3D Structure Identification of Nanoparticles by Graphene Liquid Cell Electron Microscopy, has been used to separately reconstruct the 3D structures of two individual platinum nanoparticles in solution.

A July 16, 2015 Berkeley Lab news release, which originated the news item, reveals more details about the reason for the research and the research itself,

“Understanding structural details of colloidal nanoparticles is required to bridge our knowledge about their synthesis, growth mechanisms, and physical properties to facilitate their application to renewable energy, catalysis and a great many other fields,” says Berkeley Lab director and renowned nanoscience authority Paul Alivisatos, who led this research. “Whereas most structural studies of colloidal nanoparticles are performed in a vacuum after crystal growth is complete, our SINGLE method allows us to determine their 3D structure in a solution, an important step to improving the design of nanoparticles for catalysis and energy research applications.”

Alivisatos, who also holds the Samsung Distinguished Chair in Nanoscience and Nanotechnology at the University of California Berkeley, and directs the Kavli Energy NanoScience Institute at Berkeley (Kavli ENSI), is the corresponding author of a paper detailing this research in the journal Science. The paper is titled “3D Structure of Individual Nanocrystals in Solution by Electron Microscopy.” The lead co-authors are Jungwon Park of Harvard University, Hans Elmlund of Australia’s Monash University, and Peter Ercius of Berkeley Lab. Other co-authors are Jong Min Yuk, David Limmer, Qian Chen, Kwanpyo Kim, Sang Hoon Han, David Weitz and Alex Zettl.

Colloidal nanoparticles are clusters of hundreds to thousands of atoms suspended in a solution whose collective chemical and physical properties are determined by the size and shape of the individual nanoparticles. Imaging techniques that are routinely used to analyze the 3D structure of individual crystals in a material can’t be applied to suspended nanomaterials because individual particles in a solution are not static. The functionality of proteins are also determined by their size and shape, and scientists who wanted to image 3D protein structures faced a similar problem. The protein imaging problem was solved by a technique called “single-particle cryo-electron microscopy,” in which tens of thousands of 2D transmission electron microscope (TEM) images of identical copies of an individual protein or protein complex frozen in random orientations are recorded then computationally combined into high-resolution 3D reconstructions. Alivisatos and his colleagues utilized this concept to create their SINGLE technique.

“In materials science, we cannot assume the nanoparticles in a solution are all identical so we needed to develop a hybrid approach for reconstructing the 3D structures of individual nanoparticles,” says co-lead author of the Science paper Peter Ercius, a staff scientist with the National Center for Electron Microscopy (NCEM) at the Molecular Foundry, a DOE Office of Science User Facility.

“SINGLE represents a combination of three technological advancements from TEM imaging in biological and materials science,” Ercius says. “These three advancements are the development of a graphene liquid cell that allows TEM imaging of nanoparticles rotating freely in solution, direct electron detectors that can produce movies with millisecond frame-to-frame time resolution of the rotating nanocrystals, and a theory for ab initio single particle 3D reconstruction.”

The graphene liquid cell (GLC) that helped make this study possible was also developed at Berkeley Lab under the leadership of Alivisatos and co-author Zettl, a physicist who also holds joint appointments with Berkeley Lab, UC Berkeley and Kavli ENSI. TEM imaging uses a beam of electrons rather than light for illumination and magnification but can only be used in a high vacuum because molecules in the air disrupt the electron beam. Since liquids evaporate in high vacuum, samples in solutions must be hermetically sealed in special solid containers – called cells – with a very thin viewing window before being imaged with TEM. In the past, liquid cells featured silicon-based viewing windows whose thickness limited resolution and perturbed the natural state of the sample materials. The GLC developed at Berkeley lab features a viewing window made from a graphene sheet that is only a single atom thick.

“The GLC provides us with an ultra-thin covering of our nanoparticles while maintaining liquid conditions in the TEM vacuum,” Ercius says. “Since the graphene surface of the GLC is inert, it does not adsorb or otherwise perturb the natural state of our nanoparticles.”

Working at NCEM’s TEAM I, the world’s most powerful electron microscope, Ercius, Alivisatos and their colleagues were able to image in situ the translational and rotational motions of individual nanoparticles of platinum that were less than two nanometers in diameter. Platinum nanoparticles were chosen because of their high electron scattering strength and because their detailed atomic structure is important for catalysis.

“Our earlier GLC studies of platinum nanocrystals showed that they grow by aggregation, resulting in complex structures that are not possible to determine by any previously developed method,” Ercius says. “Since SINGLE derives its 3D structures from images of individual nanoparticles rotating freely in solution, it enables the analysis of heterogeneous populations of potentially unordered nanoparticles that are synthesized in solution, thereby providing a means to understand the structure and stability of defects at the nanoscale.”

The next step for SINGLE is to recover a full 3D atomic resolution density map of colloidal nanoparticles using a more advanced camera installed on TEAM I that can provide 400 frames-per-second and better image quality.

“We plan to image defects in nanoparticles made from different materials, core shell particles, and also alloys made of two different atomic species,” Ercius says. [emphasis mine]

“Two different atomic species?”, they really are pushing that biology analogy.

Here’s a link to and a citation for the paper,

3D structure of individual nanocrystals in solution by electron microscopy by Jungwon Park, Hans Elmlund, Peter Ercius, Jong Min Yuk, David T. Limme, Qian Chen, Kwanpyo Kim, Sang Hoon Han, David A. Weitz, A. Zettl, A. Paul Alivisatos. Science 17 July 2015: Vol. 349 no. 6245 pp. 290-295 DOI: 10.1126/science.aab1343

This paper is behind a paywall.

Graphene liquid cells and movies at the nanoscale

Here’s an Oct. 3, 2013 news item on Azonano about transmission electron microscopy (TEM) and graphene liquid cells enabling researchers at the Lawrence Berkeley National Laboratory (Berkeley Lab) to make movies,

Through a combination of transmission electron microscopy (TEM) and their own unique graphene liquid cell, the researchers have recorded the three-dimensional motion of DNA connected to gold nanocrystals. This is the first time TEM has been used for 3D dynamic imaging of so-called soft materials.

The researchers have produced an animation illustrating their work,

The Oct. 3, 2013 Berkeley Lab news release, which originated the news item, goes on to describe the challenge of imaging soft materials and how the researchers solved the problem,

In the past, liquid cells featured silicon-based viewing windows whose thickness limited resolution and perturbed the natural state of the soft materials. Zettl [physicist Alex Zettl] and Alivisatos [Paul Alivisatos, Berkeley Lab Director] and their respective research groups overcame these limitations with the development of a liquid cell based on a graphene membrane only a single atom thick. This development was done in close cooperation with researchers at the National Center for Electron Microscopy (NCEM), which is located at Berkeley Lab.

“Our graphene liquid cells pushed the spatial resolution of liquid phase TEM imaging to the atomic scale but still focused on growth trajectories of metallic nanocrystals,” says lead author Qian Chen, a postdoctoral fellow in Alivisatos’s research group. “Now we’ve adopted the technique to imaging the 3D dynamics of soft materials, starting with double-strand (dsDNA) connected to gold nanocrystals and achieved nanometer resolution.”

To create the cell, two opposing graphene sheets are bonded to one another by their van der Waals attraction. This forms a sealed nanoscale chamber and creates within the chamber a stable aqueous solution pocket approximately 100 nanometers in height and one micron in diameter. The single atom thick graphene membrane of the cells is essentially transparent to the TEM electron beam, minimizing the unwanted loss of imaging electrons and providing superior contrast and resolution compared to silicon-based windows. The aqueous pockets allow for up to two minutes of continuous imaging of soft material samples exposed to a 200 kilo Volt imaging electron beam. During this time, soft material samples can freely rotate.

After demonstrating that their graphene liquid cell can seal an aqueous sample solution against a TEM high vacuum, the Berkeley researchers used it to study the types of gold-dsDNA nanoconjugates that have been widely used as dynamic plasmonic probes.

“The presence of double-stranded DNA molecules incorporates the major challenges of studying the dynamics of biological samples with liquid phase TEM,” says Alivisatos. “The high-contrast gold nanocrystals facilitate tracking of our specimens.”

The Alivisatos and Zettl groups were able to observe dimers, pairs of gold nanoparticles, tethered by a single piece of dsDNA, and trimers, three gold nanoparticles, connected into a linear configuration by two single pieces of dsDNA. From a series of 2D projected TEM images captured while the samples were rotating, the researchers were to reconstruct 3D configuration and motions of the samples as they evolved over time.