LAB REPORT

With 192 lasers and temperatures more than three times hotter than the center of the sun, scientists hit — at least for a fraction of a second — a key milestone on the long road toward nearly pollution-free fusion energy.

Researchers at the National Ignition Facility at the Lawrence Livermore National Lab were able to spark a fusion reaction that briefly sustained itself — a major feat because fusion requires such high temperatures and pressures that it easily fizzles out.

The ultimate goal, still years away, is to generate power the way the sun generates heat, by smooshing hydrogen atoms so close to each other that they combine into helium, which releases torrents of energy.

A team of more than 100 scientists published the results of four experiments that achieved what is known as a burning plasma. With those results, along with preliminary results announced last August from follow-up experiments, scientists say they are on the threshold of an even bigger advance: ignition. That’s when the fuel can continue to “burn” on its own and produce more energy than what’s needed to spark the initial reaction.

The extreme pressures and temperatures found in the cores of Earth-like planets have been recreated using an ultrahigh-power laser at Lawrence Livermore National Laboratory. The research was led by Richard Kraus and suggests that rocky planets larger than Earth should have strong magnetic fields that are sustained over billions of years. The study could provide key guidance in the continuing search for life on the growing number of Earth-like exoplanets that have been observed orbiting stars other than the sun.

When a rocky planet forms, material below the surface crust separates into a lighter silicate mantle that floats on a dense iron core. The molten core gradually loses heat to the surrounding mantle and in the case of the Earth, the inner core solidifies – releasing even more heat.

This movement of heat occurs via convection in Earth’s molten outer core – activating a dynamo process that generates a strong magnetic field. This field shields life on Earth from deadly radiation, and astrobiologists believe that such fields could be a prerequisite for organic life to emerge on other planets. However, questions remain surrounding the conditions that allow this convection to occur and remain stable over billions of years.

Antibiotics have enabled extensive control of bacterial infections, which have historically been the leading cause of death. However, the abuse of traditional antibiotics in humans and animals has led to the emergence of stronger and more powerful bacterial strains that can no longer be treated with traditional antibiotics.

Researchers at Lawrence Livermore are exploring alternative treatment options when antibiotics do not work, and they are turning to nature. Certain naturally occurring clay deposits have been shown to retain antibacterial properties and kill antibiotic-resistant bacteria. These clays have been proposed as a new paradigm for combating the potentially catastrophic effects of the post-antibiotic era. Despite their effectiveness, these naturally occurring clays exhibit variable antibacterial effects due to their inherent non-uniform properties, and the synthesis of minerals with reproducible antibacterial activity is needed to harness their therapeutic value.

A team of LLNL geochemists, cell biologists and microbiologists set out to produce fully synthetic versions of the naturally occurring antibacterial minerals, while controlling the purity and reactivity of the compounds.

LLNL scientists have developed a custom microscope to image microbes in soil and plants at the micrometer scale.

Live imaging of microbes in soil would help scientists understand how soil microbial processes occur on the scale of micrometers, where microbial cells interact with minerals, organic matter, plant roots and other microorganisms. Because the soil environment is both heterogeneous and dynamic, these interactions may vary substantially within a small area and over short timescales.

Imaging biogeochemical interactions in complex microbial systems, such as those at the soil-root interface, is crucial to studies of climate, agriculture and environmental health but complicated by the three-dimensional collocation of materials with a wide range of optical properties.

Researchers have pursued a large range of imaging techniques in efforts to understand the spatial and temporal aspects of these processes. But these same methods are unable to image microbes such as individual hyphae and bacteria because of contrast or resolution limitations. The LLNL researchers turned to optical methods — imaging with light in the ultraviolet, visible and infrared spectrum — that allowed them to image microbes in soil and plants.

"We wanted to image in the optical range because it is convenient, gentle and fast, but we knew that we needed to take a new approach to generating contrast to be able to image microbes in natural matrices," said LLNL chemist Peter Weber, the project lead.

Fundamental science often finds applications beyond its original focus. Previously, Lawrence Livermore scientists found applications for small diameter carbon nanotube porins in energy technology. Nanotube porins are tubes with walls just molecules thick that act as pores through the walls of a thin membrane of liposomes, a type of tiny synthetic particle.

But now those same LLNL scientists have assembled these nanotubes in a new way to deliver a cancer drug. The key is that the nanotubes pull the liposomes and the cancer cells together, allowing the membranes of the liposome and cancer to mix. This fusion process allows the drug to freely pass from the liposome to the cell. This results in very effective delivery of the anticancer drug doxorubicin, killing up to 90 percent of diseased cells.

This new pathway to deliver a drug directly into a cell interior addresses a long-standing challenge for medicine. It provides a new platform for understanding how to precisely deliver a wide range of drugs to individual cells. This understanding will potentially enhance the arsenal of innovative drug carriers for treatment of difficult to cure diseases. Another potential application includes more efficient methods for administering vaccines.