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Machine technology frequently
puts magnetic or electrostatic
repulsive forces to practical use,
as in maglev trains, vehicle
suspensions or non-contact
bearings. In contrast, materials
design overwhelmingly focuses
on attractive interactions, such
as in the many advanced
polymer-based composites, where inorganic fillers interact with a polymer matrix to improve
mechanical properties. However, articular cartilage strikingly illustrates how electrostatic repulsion
can be harnessed to achieve unparalleled functional efficiency: it permits virtually frictionless
mechanical motion within joints, even under high compression. Here we describe a composite
hydrogel with anisotropic mechanical properties dominated by electrostatic repulsion between
negatively charged unilamellar titanate nanosheets embedded within it. Crucial to the behaviour of this
hydrogel is the serendipitous discovery of cofacial nanosheet alignment in aqueous colloidal
dispersions subjected to a strong magnetic field, which maximizes electrostatic repulsion6 and thereby
induces a quasi-crystalline structural ordering over macroscopic length scales and with uniformly
large face-to-face nanosheet separation. We fix this transiently induced structural order by
transforming the dispersion into a hydrogel using light-triggered in situ vinyl polymerization. The
resultant hydrogel, containing charged inorganic structures that align cofacially in a magnetic flux,
deforms easily under shear forces applied parallel to the embedded nanosheets yet resists compressive
forces applied orthogonally. We anticipate that the concept of embedding anisotropic repulsive
electrostatics within a composite material, inspired by articular cartilage, will open up new
possibilities for developing soft materials with unusual functions.

Resilience is a system's ability to cope with change, or to bounce back after stress. The loss of resilience in a natural system occurs when the stress exceeds a certain threshold, beyond which the system loses its ability to bounce back and retain proper functionality. For instance, when the loss of trees in a forest (deforestation) crosses a tipping point and the forest turns barren, or when the load on the electrical power grid becomes too high and a massive power failure emerges. The challenge is that most complex systems are multidimensional, disordered and described by nonlinear dynamics - characteristics that firmly avoid analytical treatment. We address this challenge by showing how to map a complex system into an effective one dimensional equation, exposing the universal patterns of resilience exhibited by diverse systems, from ecological to technological networks. Along the way we will understand why systems lose resilience all of a sudden, learn how to predict such resilience loss and show how to fortify a system to become more resilient.


J. Gao, B. Barzel, A-L Barabasi, Nature 530, 307 (2016).

The structure and evolution of planets is determined by material behavior at high pressure. Such high pressures can only be achieved at High Energy Density (HED) facilities like Sandia’s Z machine and high-power laser facilities. Z stores 22MJ of energy that is released in pulses of up to 25MA peak current with 200-1000ns rise times. The large currents generate strong magnetic fields that can be used to create high pressures in dynamic material experiments. This capability enables evaluation of material equation-of-state and other properties in extreme conditions. I will present three examples using experimental results from the Z machine to answer long-standing questions in planetary science. First, solar system evolution models have been unable to consistently account for observations of Jupiter and Saturn. Recent Z observations of a first-order liquid-liquid insulator to metal transition in hydrogen may shed light on this discrepancy. Second, measurements of iron vaporization may address troubling differences between models of the Earth’s moon forming event and observations of the Earth and moon’s compositions. Finally, precise measurements of high-pressure water were used to validate DFT models which in turn informed planetary structure models suggesting an explanation of the multi-polar magnetic fields of Neptune and Uranus.
The Z Fundamental Science Program (ZFSP), which enables the academic community to take advantage of the facility enabling much of this work, will be described.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Next-generation sequencing (NGS) has increased our understanding of biological phenomena and human disease by enabling highly sensitive transcriptome analysis across a large dynamic range of RNA expression levels. As exciting new applications for NGS emerge, Clontech continues to develop powerful new tools for life science research by improving and building upon its core technologies. A common feature of Clontech® NGS kits is SMART® technology, which harnesses the template-switching activity of customized reverse transcriptases to enable researchers to analyze their most challenging samples, such as ultra-low input or single-cell RNA, noncoding RNA, and RNA from degraded samples. In particular, single-cell RNA-seq is one of the fastest-growing applications of NGS, and the SMARTer Ultra® Low mRNA-seq family of products, featuring a highly sensitive, dT-primed mechanism, has become the gold standard for this type of analysis. The newest generations of ultra-low input/single-cell mRNA-seq and picogram-input total RNA-seq kits have brought increased sensitivity to SMART technology by improving upon the SMART-Seq® method and incorporating locked nucleic acid (LNA) technology. Expanding applications for SMART technology have led to a ligation-free method for generating ChIP (chromatin immunoprecipitation) sequencing libraries. This seminar will take you on a tour of these new technologies and highlight ongoing research on a variety of NGS applications, including single-cell RNA-seq.