Science Society

In this episode, we're privileged to host Dr. Finger, a leading figure in the field of pancreatic islet transplantation. We explore the intricacies of this potentially life-altering treatment for diabetes, which, while promising, faces significant hurdles related to the supply chain and quality control of donor islets.

Dr. Finger takes us through the transformative potential of cryopreservation to solve these challenges. The key, he explains, lies in the meticulous optimization of cryoprotectant agent composition, loading and unloading conditions, and methods for vitrification and rewarming. This strategy can successfully preserve islets from a variety of sources, including mice, pigs, humans, and even human stem cell-derived beta cells.

Our discussion reveals that these post-cryopreservation islets maintain high viability, not only immediately after rewarming but also after extended cryogenic storage of up to 9 months. Dr. Finger outlines how these islets retain normal macroscopic, microscopic, and ultrastructural morphology and largely maintain cellular respiration and glucose-stimulated insulin secretion functionality.

The conversation takes an exciting turn as we explore the practical application of these findings. Dr. Finger shares insights into how cryopreserved islets behave in vivo, with examples from porcine and stem cell-derived beta cell xenotransplant models, as well as a mouse syngeneic transplant model. In these models, cryopreserved islets produced insulin and, impressively, restored normal blood sugar levels within 24-48 hours in a high percentage of cases.

Finally, we discuss the scalability of this approach and its implications for improving the transplantation outcomes for diabetes patients. Dr. Finger's research paints a bright future for the practicality of islet transplantation, offering hope to countless individuals living with diabetes. If you're curious about cutting-edge diabetes research and the transformative potential of cryopreservation, this episode with Dr. Finger is a must-listen.

https://doi.org/10.1038/s41591-022-01718-1 Pancreatic islet cryopreservation by vitrification achieves high viability, function, recovery, and clinical scalability for trans plantation

In this fascinating episode, we sit down with Dr. Spontak, an expert in polymeric membranes, to discuss the latest breakthroughs in carbon dioxide capture technology. As global climate change continues to dominate scientific and public discourse, the need for effective, low-cost, and scalable carbon capture solutions has never been greater.

Dr. Spontak introduces us to a groundbreaking hybrid-integrated membrane strategy that could change the face of carbon capture. His team's innovative design overcomes the long-standing tradeoff between permeability - the speed at which gases flow through the membrane - and selectivity - the ability to separate one gas from another.

The layered design incorporates a base layer of porous polyacrylonitrile for structural support, and a middle layer of either elastomer-like polydimethylsiloxane or glassy-type polytetrafluoroethylene. The key to their approach, however, is the patchy layer of polyamine they graft onto these substrates. This selective layer attracts carbon dioxide, pulling it into the membrane and facilitating its separation from nitrogen.

Dr. Spontak guides us through the underlying principles of this approach, explaining how the high-solubility mechanism of the polyamine layer, when hydrated by water vapor naturally present in gas streams, enriches the concentration of CO2. This then allows for rapid transport of CO2 through the permeable substrate.

We also explore the impressive results achieved by this method - not only does the new membrane design retain much of its high CO2 permeability, but it also achieves a staggering increase in CO2 selectivity. If you're interested in how the fields of materials science and environmental science intersect and the technological advancements propelling us toward a more sustainable future, then you won't want to miss this engaging conversation with Dr. Spontak.

New polymer membrane tech improves efficiency of CO2 capture http://dx.doi.org/10.1126/science.abj9351

Join us for the weekly recap! Did you miss our guest speaker talks? Do you still have unanswered questions? During the weekly recap we will summarize the guest speaker rooms we had the previous week.

In this insightful episode, we are joined by Dr. Sarwat from IBM Research, who introduces us to the groundbreaking realm of phase-change memtransistive synapses for neuromorphic computing. This new field is inspired by the biological nervous system's ability to adapt and learn, bringing transformative potential to the world of computing.

Neuromorphic computing aims to recreate the functionalities of the mammalian nervous system, where multiple synaptic plasticity rules operate over wide-ranging timescales to enable learning and memory formation. Dr. Sarwat explains the challenges of achieving this in artificial synapses and how conventional methods fall short in emulating these dynamic functionalities.

We delve into the workings of phase-change memtransistive synapses, a novel solution that leverages the non-volatility of phase configurations and the volatility of field-effect modulation for implementing tunable plasticities. These unique synapses can enable intricate plasticity rules such as short-term spike-timing-dependent plasticity, enhancing our ability to model dynamic environments.

Dr. Sarwat further discusses how these memtransistive synapses are efficiently used in realizing accelerators for Hopfield neural networks, addressing combinatorial optimization problems. This fascinating conversation explores the frontier of neuromorphic computing and highlights the potential these advancements hold for the future of computing. Whether you're a computer science enthusiast or someone interested in how nature inspires technology, this episode promises to expand your understanding of cutting-edge research in neuromorphic computing.

Keywords: Neuromorphic Computing, Artificial Synapses, Synaptic Plasticity, Long-term Plasticity, Short-term Plasticity, Phase-Change Memtransistive Synapses, Spike-Timing-Dependent Plasticity, Hopfield Neural Networks, Combinatorial Optimization, Dynamic Environments.

https://doi.org/10.1038/s41565-022-01095-3

In this enlightening episode, we are joined by Dr. Arlehamn as we delve into the complex world of Parkinson's Disease (PD), a multi-stage neurodegenerative disorder with largely unknown causes. Recently, T cells have been identified to play a significant role in the autoimmune features associated with PD.

Dr. Arlehamn takes us through his team's cutting-edge research that involves RNA sequencing on PBMC and peripheral CD4 and CD8 memory T cell subsets derived from PD patients and age-matched healthy controls. When these groups were stratified by their T cell responsiveness to alpha-synuclein (α-syn), the study revealed a broad differential gene expression profile in memory T cell subsets and a specific PD associated gene signature.

Notably, this investigation led to the identification of significant enrichment of transcriptomic signatures previously associated with PD, including those for oxidative stress, phosphorylation, autophagy of mitochondria, cholesterol metabolism, inflammation, and the chemokine signaling proteins CX3CR1, CCR5, and CCR1. Moreover, the team identified genes in these peripheral cells that have previously been shown to be involved in PD pathogenesis and expressed in neurons, such as LRRK2, LAMP3, and aquaporin.

Together, these findings suggest that characteristics of circulating T cells with α-syn-specific responses in PD patients provide valuable insights into the interactive processes occurring during PD pathogenesis. This episode is a deep dive into the advanced research around PD, its autoimmune aspects, and the potential targets for intervention. Whether you're a neurology enthusiast or someone interested in understanding the mechanisms behind neurodegenerative diseases, this episode promises to be a highly informative and intriguing conversation.

Keywords: Parkinson's Disease (PD), Neurodegenerative disorder, Autoimmune features, T cells, RNA sequencing, PBMC, CD4, CD8, Memory T cell subsets, Alpha-synuclein (α-syn), Inflammatory autoimmune response, PD associated gene signature, Oxidative stress, Phosphorylation, Autophagy of mitochondria, Cholesterol metabolism, Inflammation, Chemokine signaling, CX3CR1, CCR5, CCR1, LRRK2, LAMP3, Aquaporin.

https://doi.org/10.1038/s41531-022-00282-2

In this thought-provoking episode, Dr. Ghimire joins us to discuss his research on topological nanospasers, an emerging field of study with vast potential for applications in diverse areas including infrared spectroscopy, sensing, probing, and biomedical treatment.

A topological nanospaser, as Dr. Ghimire explains, is a system consisting of a silver nanospheroid and a MoS2 monolayer flake with a circular shape. The metal nanospheroid functions as a plasmonic nanoresonator, supporting two rotating modes, which are coupled to the corresponding valleys of MoS2. When external circularly polarized light is applied, it selectively pumps only one of the valleys of MoS2, and this interaction underpins the generation of the spaser dynamics.

Dr. Ghimire elaborates on how the generated spaser dynamics are strongly influenced by the size (radius) of the MoS2 nanoflake. For a small radius, the system has a single spasing regime where only the chirally matched plasmon mode is generated. However, as the size of the MoS2 increases, there can be two distinct regimes depending on the pump intensity. In one regime, only the chirally matched plasmon mode is generated, while in the other, both chirally matched and chirally mismatched modes can exist. Fascinatingly, these different spaser operation regimes have opposite handedness in the far-field radiated spaser system.

This episode provides a deep dive into the exciting world of topological nanospasers. Whether you're a physicist, a researcher, a student or simply interested in the latest breakthroughs in nanotechnology, this conversation with Dr. Ghimire is sure to captivate you.

Keywords: Topological nanospaser, Silver nanospheroid, MoS2 monolayer flake, Plasmonic nanoresonator, Rotating modes, Valleys, External circularly polarized light, Spaser dynamics, Chirally matched plasmon mode, Chirally mismatched mode, Infrared spectroscopy, Sensing, Probing, Biomedical treatment.

https://doi.org/10.1021/acsphotonics.0c01919

In this episode, we're honored to host Dr. Persson, who explores one of the most intriguing challenges in quantum physics - explaining the emergence of the classical spacetime geometry from a more fundamental, microscopic perspective.

Dr. Persson guides us through the intricacies of the gauge/gravity-correspondence, a holographic framework that associates a supergravity theory in five-dimensional Anti-deSitter space with a strongly coupled superconformal gauge theory on its 4-dimensional flat Minkowski boundary. In this context, the classical geometry should manifest from a specific quantum state of the dual gauge theory.

Supporting this principle, Dr. Persson presents compelling research, demonstrating how the classical metric emerges from a canonical state in the dual gauge theory. In this remarkable journey, we gain insights into the Sasaki-Einstein metric, which forms the foundation of supergravity geometry. This metric is represented through an explicit integral formula that involves the canonical quantum state in question.

Venturing further, Dr. Persson discusses toric quiver gauge theories, and illustrates how, in these particular cases, our results can be computationally simplified through a process known as 'tropicalization'.

Join us in this captivating conversation with Dr. Persson to explore the intersection of quantum physics and classical geometry, revealing how our understanding of the universe is being reshaped by these groundbreaking concepts. Whether you are a quantum physics enthusiast or a curious mind seeking to understand the mysteries of our universe, this episode is a must-listen.

Keywords: Quantum theory of gravity, Classical spacetime geometry, Gauge/gravity-correspondence, Supergravity theory, Five-dimensional Anti-deSitter space, Superconformal gauge theory, 4-dimensional flat Minkowski boundary, Quantum state, Sasaki-Einstein metric, Toric quiver gauge theories, Tropicalization.

https://doi.org/10.1038/s41467-021-27951-9

Join us in this engaging episode with Dr. Singh, who introduces us to an exciting application of machine learning in the realm of material science. He elucidates how chemical alloying can impact the formation enthalpy of rare-earth intermetallics.

The use of machine learning in rare-earth intermetallic design has been minimal, largely due to the limited availability of reliable datasets. To overcome this, Dr. Singh and his team have developed an extensive 'in-house' rare-earth database, containing over 600 compounds. Each entry in this database is enriched with formation enthalpy data and associated atomic features obtained using high-throughput density-functional theory (DFT).

With this resource at their disposal, Dr. Singh's team then applied the SISSO (Sure Independence Screening and Sparsifying Operator) based machine learning method to train and test the formation enthalpies of these rare-earth compounds. This approach enabled them to delve into the effects of transition metal alloying on the energy stability of Ce based cubic Laves phases (MgCu type).

The SISSO predictions, which align well with high-fidelity DFT calculations and X-ray powder diffraction measurements, provide invaluable quantitative guidance for compositional considerations within a machine-learning model. This contributes significantly to the discovery of new metastable materials.

To deepen our understanding, Dr. Singh also analyzes the electronic-structure of a Ce-Fe-Cu based compound, offering insights into the electronic origin of phase stability. This fusion of interpretable analytical models, density-functional theory, and experimental methods presents a quick and reliable design guide for discovering technologically useful materials.

Whether you're a materials scientist, a machine learning enthusiast, or just someone fascinated by the intersection of technology and science, this episode with Dr. Singh is a must-listen!

Keywords: Machine learning, Rare-earth intermetallics, Chemical alloying, Formation enthalpy, High-throughput density-functional theory (DFT), SISSO, Energy stability, Cubic Laves phases, Metastable materials, Electronic-structure, Phase stability, Material discovery.

https://doi.org/10.1016/j.actamat.2022.117759

Did you miss our rooms this week? Would like to have a short summary of our weekly guest speaker talks? Do you still have a question about a topic we discussed? Join us for the weekly recap!

In this intriguing episode, we chat with Dr. Krasnokutski about the fascinating subject of organic molecules present in the dense interstellar medium. Dr. Krasnokutski sheds light on how these complex molecules come into being under typical space conditions and their potential implications for understanding the origins of life.

Scientists have managed to synthesize many of these molecules in laboratory conditions mimicking interstellar environments. Still, up until now, only relatively small molecules of biological interest have been shown to form. Dr. Krasnokutski and his team push the boundaries of this understanding, demonstrating the formation of isomeric polyglycine monomers (aminoketene molecules) from the condensation of carbon atoms on the surface of cold solid particles, much like cosmic dust.

In a further groundbreaking revelation, Dr. Krasnokutski explains how these aminoketene molecules, upon encountering each other, polymerize to produce peptides of different lengths. The process, which intriguingly involves three of the most abundant species present in star-forming molecular clouds - CO, C, and NH3, bypasses the typical stage of amino acid formation in protein synthesis.

What's more? This unique chemistry can efficiently occur even at low temperatures, without the need for irradiation or the presence of water. Dr. Krasnokutski postulates that the delivery of biopolymers formed by this novel chemistry to rocky planets in the habitable zone might play a crucial role in the origins of life.

This episode offers a deep-dive into a truly groundbreaking study at the intersection of chemistry, astrophysics, and astrobiology. Whether you are a student of these fields or simply a space enthusiast curious about the mysteries of the universe, this conversation with Dr. Krasnokutski will certainly pique your curiosity.

Keywords: Organic molecules, Interstellar medium, Aminoketene molecules, Polyglycine monomers, Peptides, CO, C, NH3, Protein synthesis, Low temperatures, Biopolymers, Origins of life.

https://doi.org/10.1038/s41550-021-01577-9