Scientific Discovery

Orthogonal Biosensor

Challenge

Canary in a coal mine? Not quite—more like a yeast cell in a silica micro-chamber. But the principle is quite similar. The canary served as a toxic gas detector in mines—a biosensor. In like manner, the silica-encapsulated cells in this technology can serve as sensors of a variety of environmental agents. The difference, perhaps, is that the canary had to collapse, often die, whereas the cells need only send and amplify a signal telling a human observer that something of interest has been detected. There are several reasons to look at living cells as potential biosensors, not the least of which is that cells possess intrinsic amplification mechanisms to transduce detected analytes into more robust responses. Additionally, the diversity of cellular proteins and other macromolecules provides a huge battery of molecular specificities for accurate recognition events. On the other hand, unlike strictly electromechanical devices, cells require an environment that sustains their metabolism and protects them from dehydration.

NuSTAR

Lab optics achieve orbit on NASA’s NuSTAR

On July 13, 2012, NASA successfully launched its Nuclear Spectroscopic Telescope Array (NuSTAR) satellite to observe the most energetic objects in the universe, including black holes and relativistic jets. NuSTAR is the first-ever satellite to focus high-energy x-rays, and it is these special optics that make possible a 100-fold increase in sensitivity over any previous hard x-ray device. This sensitivity will enable scientists to see objects such as supernovae in great enough detail to test current theories, as well as the black holes believed to be at the center of all galaxies and “extreme objects” that have never been directly seen before, such as relativistic jets.

One-dose Killing of Cancer Cells

Structure of the engineered lipid bilayer covering and cutaway of the nanoporous silica interior of a protocell, showing the diversity of cytotoxic cargo that it can potentially deliver into the interior of a cancer cell.

Sound futuristic? Perhaps not. Capturing the cover of the May 2011 (April 17 online) issue of Nature Materials, a paper first-authored by Sandia Truman Fellow Carlee Ashley and describing (partly LDRD-funded) work from the lab of Sandia Laboratory Fellow and UNM Distinguished Professor, Jeff Brinker presents a genuinely evolved route to that possible outcome (one-dose cancer-cell killing). Dubbed “protocells,” this ingenious nanoparticulate engineering of organic and inorganic materials goes one-better on liposomes, an already FDA-approved method of drug delivery. While a liposome is simply a bag of aqueous solution encapsulated by a ligand-decorated lipid-bilayer membrane (the same type of membrane that encloses all higher [eukaryotic] cells and many of their internal structures [organelles]), a protocell is far more nanostructurally complex. The outer bag of lipid bilayer encloses a nanoporous silica nanoparticle that acts as a high-surface-area container-binder for a diversity of cytotoxic compounds—drugs, nucleic acids (such as small interfering RNAs [siRNA]), proteins, and peptides of varying water solubility, some of which do not dissolve well in the aqueous internal medium of liposomes.

First Z bosons ever produced and reconstructed

The first Z boson candidate reconstructed in heavy ion collisions. The figure shows the calorimetric and charged particle tracking response to a lead-lead collision in the CMS detector plus the two muon tracks from the Z0 decay.

The Z boson is an electrically neutral subatomic particle that mediates the weak nuclear force. It has a mass 182,000 times that of the electron. Unlike the other weak force mediator (the W boson), the Z boson does not change particles it interacts with into other types of particles.

In November, Los Alamos researchers participated in data collection at the Compact Muon Solenoid (CMS) experiment. The CMS experiment consisted of lead-lead collisions at the unprecedented energy of 2.76 GeV (a factor 14 higher than at the Relativistic Heavy Ion Collider) at the Large Hadron Collider at CERN. Their goal is to understand the quark gluon plasma on a quantitative level.

Nanotechnology Brightens the Future

Image and transmission electron micrograph of a quantum dot nanocrystal with a cadmium selenide core and a cadmium sulfide shell separated by a thin CdSeS interfacial alloy layer.

Nanotechnology Brightens the Future of Nanocrystal Lasers

Quantum dots’ prospects for use in laser applications are improved as a result of a study showing how to limit a deleterious effect that robs the semiconductor nanocrystals of their potential lasing power. In 2000, Los Alamos National Laboratory scientists and collaborators demonstrated that quantum dots could be made to lase (Science 290, 314; DOI:10.1126), a demonstration that showed potential applications in optics. Despite the proof‐of-principle experiment, nanocrystal lasing has remained impractical. Spatial confinement of electronic excitations in the seiconductor nanocrystals enhances a fast relaxation process known as Auger recombination. This recombination quenches the electronic excitations required for lasing and causes electron, rather than photon, emission. Now Laboratory scientists have published significant advances in understanding and controlling the Auger recombination process in nanocrystal quantum dots. This work could open the door to exciting new applications of nanocrystals in practical lasing technologies.

Nanoscopic Particles Resist Full Encapsulation

Matt Lane examines a simulation depicting two polymer-coated nanoparticles in water

Featured as the cover article in the June 11, 2010, issue of Physical Review Letters, this research by Sandia National Laboratories’ Matt Lane and Gary Grest has uncovered another nanorealm phenomenon that does not obey principles expected from macroscopic events. In this instance, the phenomenon relates to surrounding nanoparticles with a protective coating.

Power Spectrum Emulator Code for Cosmology Studies

Many of the most exciting questions in cosmology, including observational probes of dark energy, rely on an understanding of the nonlinear regime of cosmic structure formation. In order to exploit the information available from this regime and to extract cosmological constraints, accurate theoretical predictions are needed. Currently, expensive numerical simulations are required to produce accurate predictions for structure formation from differing cosmological parameters. Fast prediction tools, called emulators, based on a relatively small number of high-precision simulations, could replace the simulator in the analysis work.

Ion Beam Materials

Ion Beam Materials Lab helps confirm that the moon is bone dry

A team of scientists at Los Alamos National Laboratory used an ion beam in a basement room at the Laboratory to simulate solar winds on the surface of the Moon. The table-top simulation helped confirm that the Moon is inherently dry.

In research published today in Science Express, Zachary Sharp of the University of New Mexico and a team of scientists from California, Texas, and New Mexico—including Yongqiang Wang, leader of Los Alamos’ Ion Beam Materials Lab—present an analysis of chlorine isotopic ratios in lunar rock samples that seem to indicate that the Moon never had water of its own.

Supernova Explosions

Supernova explosions caused by the collapse of stellar cores play an essential role in the evolution of the Universe, from controlling the temperature of the gas and the rate of star formation in the galactic disk to synthesizing and dispersing heavy elements. Therefore, researchers need a better understanding of how these events occur. One way is to analyze the time evolution of the emitted neutrinos that are copiously generated during the first 10 seconds after a star's collapse. By observing the signatures of the expanding shock and the postshock region in the neutrino signal, scientists could learn about the development of the explosion during the crucial first 10 seconds. This information could be inaccessible in other ways.

International Team Discovers Element 117

An international team of scientists from Russia and the United States, including two Department of Energy national laboratories and two universities, has discovered the newest superheavy element, element 117.

The team included scientists from the Joint Institute of Nuclear Research (Dubna, Russia), the Research Institute for Advanced Reactors (Dimitrovgrad), Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, Vanderbilt University, and the University of Nevada, Las Vegas.

Carbon Nanostructures

A Los Alamos National Laboratory toxicologist and a multidisciplinary team of researchers have documented potential cellular damage from “fullerenes”—soccer-ball-shaped, cage-like molecules composed of 60 carbon atoms. The team also noted that this particular type of damage might hold hope for treatment of Parkinson’s disease, Alzheimer’s disease, or even cancer.

The research recently appeared in Toxicology and Applied Pharmacology and represents the first-ever observation of this kind for spherical fullerenes, also known as buckyballs, which take their names from the late Buckminster Fuller because they resemble the geodesic dome concept that he popularized.

Secrets of a Deadly Disease

Biomedical scientist Brett Chromy and a research team from Lawrence Livermore National Laboratory are using a new system that examines pathogen-host interactions one cell at a time to trap and manipulate fluorescently labeled Yersinia pestis(plague) cells and bring these trapped cells in contact with monocytes-white blood cells in the human immune system. The team is studying the interaction between mutant strains of Y. pestis and healthy host cells to determine whether the mutant strains are deficient in a protein system called Type III secretion-the main mechanism by which the bacteria infect a host. The team hopes this research will reveal if certain mutations reduce the ability of Y. pestis cells to adhere to a host. This research is an outgrowth of the LDRD project, "The Elegant Molecular Syringe: Characterizing the Injectisome of the Yersinia pestis Type III Secretion System."

HIV Vaccine Strategy Expands Immune Responses

Two teams of researchers—including Los Alamos National Laboratory theoretical biologists Bette Korber, Will Fischer, Sydeaka Watson, and James Szinger—have announced an HIV vaccination strategy that has been shown to expand the breadth and depth of immune responses in rhesus monkeys. Rhesus monkeys provide the best animal model currently available for testing HIV vaccines.

The research appeared in two back-to-back articles in Nature Medicine this week, and outlines a strategy, called “mosaic vaccines,” for reducing the spread of HIV, the virus that causes AIDS.

Isolating Pathogens for Speedy Identification

Quickly identifying pathogens, especially viruses, can be crucial at the start of a disease outbreak such as H1N1 influenza, severe acute respiratory syndrome (SARS), or any of the many viruses that can initiate an epidemic. Rapid characterization could also speed the response following the deliberate release of a viral biological warfare agent.

Nanomaterials for the Future

Nanomaterials for Fusion Application Targets

Less than 20 years ago, nanomaterials—substances on the scale of one-billionth of a meter—were a curiosity. Today, their diverse technological applications seem to be endless. Materials reduced to the nanoscale show very different physical, chemical, and mechanical properties compared to those they exhibit on a macroscale. For example, nanoparticles have electronic structures that lie between that of bulk materials and atomic or molecular structures. Nanomaterials have real potential for impact in applications such as alternative energy conversion and energy harvesting. The development of new nanomaterials will also lead to new mass-produced consumer products in cosmetics, cars, building components, clothes, health, and new smart electronic devices. Novel assembly and manipulation of nanostructured materials in confined geometries with tailored composition and function will have applications in catalysis, sensing, hydrogen storage, advanced nuclear materials, corrosion-resistant coatings, and photonics.

Mesoscale No-man's Land

Parallel Kinetic Monte Carlo Simulation

This project focuses on the development of a general purpose parallel code for new modeling initiatives at the materials mesoscale. There are numerous parallel codes that model at the atomic/molecular or nanoscale, both those based on Molecular Dynamics and those based on Density Functional Theory. And at the macroscale, there are, likewise, a variety of parallel codes from different perspectives. However, at intermediate length scales, there exist solely special-purpose codes, which do not address the need for a general-purpose code to support new modeling initiatives at that scale.

Nanotech Discovery Saves Lives

Nanoscience—the study of things of “little” importance, one might quip—led to the largest biological simulation ever, which helped Los Alamos scientists decode genetic information. The methodology paved the way for developing new antibiotics and modeling the entire protein synthesis process—a process crucial to saving lives.

The body comprises enumerable nanofactories called ribosomes that work overtime to keep us alive. In each of our trillions of cells, a million ribosomes create proteins—chains of amino acids—that are the basis of life. A quintillion protein factories rebuild our entire body every seven years.

Networks of the Future

The picture of a future with wireless sensor networks— webs of sensory devices that function without a central infrastructure—is coming into sharper focus through the work of Laboratory computer scientist Sami Ayyorgun.

Proponents of this new technology see a world with deployments to improve a wide range of operations. Engineers could wirelessly monitor miles of gas and oil pipelines stretching across arid land for ruptures, damage, and tampering. Rescue workers might detect signs of life under the rubble of a collapsed building after an earthquake, thanks to a network of sensors inside the structure. Armed forces could keep an eye on a combat zone or a vast international border via a sensor network that promptly could provide alerts of any intrusion or illicit trafficking.

Better Breast Cancer Detection

Women may eventually have access to safer, more-comfortable, and more-accurate breast cancer scans. Currently, the only routine breast-screening technology is mammography, which uses low-dose x-rays to scan through tissue and capture on film a two-dimensional (2D) projection of the breast.