Lifeboat Foundation

High-energy, short-pulse laser sources exist only in a limited number of colors. Researchers in the 1960s found that a liquid-filled cell, which had inadvertently been placed inside a laser’s cavity, shifted the laser’s wavelength. Now a team of scientists from Brookhaven National Laboratory (BNL), New York, show that synthetic, room-temperature liquid salts can also serve as effective laser-color-tuning media [1]. The finding could lead to a simple and energy-efficient tool for creating lasers with desired colors for medical and scientific applications.

In the 1960’s liquid technique, when a photon “hits” a liquid molecule, the photon loses energy, exiting the medium with less energy—and thus a different color—than it entered (see Focus: Holey Fibers Shed New Light). The BNL team reasoned that a salt solution could interact with photons in the same way while offering a high density of energy-swapping sites compared to either a gas or a standard liquid. The vast array of available artificial salts could also make it possible to precisely tune the energy loss caused by the salt–photon interaction, giving increased color control.

The researchers assembled their converter setup from a pulsed green laser and a 63-cm-long cell filled with a salt solution. Passing the laser through the cell, they observed that the light turned orange. The researchers measured a high color-conversion efficiency of the photons, which they attribute to the large interaction cross sections of the salt molecules and to the reduction of other forms of scattering that can inhibit wavelength conversion. The group is currently designing liquids to turn this and other lasers to myriad colors.

After the introduction of the fifth-generation technology standard for broadband cellular networks (5G), engineers worldwide are now working on systems that could further speed up communications. The next-generation wireless communication networks, from 6G onward, will require technologies that enable communications at sub-terahertz and terahertz frequency bands (i.e., from 100GHz to 10THz).

While several systems have been proposed for enabling communication at these frequency bands specifically for personal use and local area networks, some applications would benefit from longer communication distances. So far, generating high-power ultrabroadband signals that contain information and can travel long distances has been challenging.

Researchers at the NASA Jet Propulsion Laboratory (JPL), Northeastern University and the Air Force Research Laboratory (AFRL) have recently developed a system that could enable multi-gigabit-per-second (Gbps) communications in the sub-terahertz frequency band over several kilometers. This system, presented in a paper in Nature Electronics, utilizes on-chip power-combining frequency multiplier designs based on Schottky diodes, semiconducting diodes formed by the junction of a semiconductor and a metal, developed at NASA JPL.

Gene therapies have the potential to treat neurological disorders like Alzheimer’s and Parkinson’s diseases, but they face a common barrier—the blood-brain barrier. Now, researchers at the University of Wisconsin-Madison have developed a way to move therapies across the brain’s protective membrane to deliver brain-wide therapy with a range of biological medications and treatments.

“There is no cure yet for many devastating brain disorders,” says Shaoqin “Sarah” Gong, UW-Madison professor of ophthalmology and visual sciences and biomedical engineering and researcher at the Wisconsin Institute for Discovery. “Innovative brain-targeted delivery strategies may change that by enabling noninvasive, safe and efficient delivery of CRISPR genome editors that could, in turn, lead to genome-editing therapies for these diseases.”

CRISPR is a molecular toolkit for editing genes (for example, to correct mutations that may cause disease), but the toolkit is only useful if it can get through security to the job site. The blood-brain barrier is a membrane that selectively controls access to the brain, screening out toxins and pathogens that may be present in the bloodstream. Unfortunately, the barrier bars some beneficial treatments, like certain vaccines and gene therapy packages, from reaching their targets because in lumps them in with hostile invaders.

Violence and warfare were widespread in many Neolithic communities across Northwest Europe, a period associated with the adoption of farming, new research suggests.

Of the skeletal remains of more than 2,300 early farmers from 180 sites dating from around 8,000—4,000 years ago to, more than one in ten displayed weapon injuries, bioarcheologists found.

Contrary to the view that the Neolithic era was marked by peaceful cooperation, the team of international researchers say that in some regions the period from 6000BCE to 2000BCE may be a high point in conflict and violence with the destruction of entire communities.

A study conducted in Brazil and reported in an article published in Molecular Psychiatry suggests that schizophrenia may be associated with alterations in the vascularization of certain brain regions. Researchers at the State University of Campinas (UNICAMP), D’Or Research and Education Institute (IDOR) and the Federal University of Rio de Janeiro (UFRJ) found a link between astrocytes (central nervous system cells) from patients with schizophrenia and formation of narrow blood vessels.

Schizophrenia is a severe multifactorial mental health disorder affecting around 1% of the world population. Common symptoms include loss of contact with reality (psychosis), hallucinations (hearing voices, for example), delusions or delirium, disorganized motor behavior, loss of motivation and cognitive impairment.

In the study, the researchers focused on the role of astrocytes in development of the disease. These glial cells are housekeepers of the central nervous system and important to its defense. They are the central elements of the neurovascular units that integrate neural circuitry with local blood flow and provide neurons with metabolic support.

Lasers are intense beams of colored light. Depending on their color and other properties, they can scan your groceries, cut through metal, eradicate tumors, and even trigger nuclear fusion. But not every laser color is available with the right properties for a specific job.

To fix that, scientists have found a variety of ways to convert one color of laser light into another. In a study just published in the journal Physical Review Applied, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory demonstrate a new color-shifting strategy that is simple, efficient, and highly customizable.

The new method relies on interactions between the laser and vibrational energy in the chemical bonds of materials called “ionic liquids.” These liquids are made only of positively and negatively charged ions, like ordinary table salt, but they flow like viscous fluids at room temperature. Simply shining a laser through a tube filled with a particular ionic liquid can downshift the laser’s energy and change its color while retaining other important properties of the laser beam.

Michael Levin is an American developmental and synthetic biologist at Tufts University. His research interests include: bioelectrical signals by which cells communicate to serve the dynamic anatomical needs of the organism during development, regeneration, and cancer suppression; basal cognition and intelligence in diverse unconventional substrates; and top-down control of form and function across scales in biology.

Join us as we discuss.
- Bioelectricity.
- Regeneration.
- The future in medicine.
- The act of free will and more.

Continue reading “Rekindi #29 — Bioelectricity, Regeneration, Cancer Suppression & Xenobots — with Michael Levin” »

Mathematicians came up with the first examples of intransitive dice more than 50 years ago, and eventually proved that as you consider dice with more and more sides, it’s possible to create intransitive cycles of any length. What mathematicians didn’t know until recently was how common intransitive dice are. Do you have to contrive such examples carefully, or can you pick dice randomly and have a good shot at finding an intransitive set?

Looking at three dice, if you know that A beats B and B beats C, that seems like evidence that A is the strongest; situations where C beats A should be rare. And indeed, if the numbers on the dice are allowed to add up to different totals, then mathematicians believe that this intuition holds true.

But a paper posted online late last year shows that in another natural setting, this intuition fails spectacularly. Suppose you require that your dice use only the numbers that appear on a regular die and have the same total as a regular die. Then, the paper showed, if A beats B and B beats C, A and C have essentially equal chances of prevailing against each other.

Physicists at Leipzig University have once again gained a deeper understanding of the mechanism behind superconductors. This brings the research group led by Professor Jürgen Haase one step closer to their goal of developing the foundations for a theory for superconductors that would allow current to flow without resistance and without energy loss. The researchers found that in superconducting copper-oxygen bonds, called cuprates, there must be a very specific charge distribution between the copper and the oxygen, even under pressure.

This confirmed their own findings from 2016, when Haase and his team developed an experimental method based on magnetic resonance that can measure changes that are relevant to superconductivity in the structure of materials. They were the first team in the world to identify a measurable material parameter that predicts the maximum possible transition temperature —a condition required to achieve superconductivity at room temperature. Now they have discovered that cuprates, which under pressure enhance superconductivity, follow the charge distribution predicted in 2016. The researchers have published their new findings in the journal PNAS.

“The fact that the transition temperature of cuprates can be enhanced under pressure has puzzled researchers for 30 years. But until now we didn’t know which mechanism was responsible for this,” Haase said. He and his colleagues at the Felix Bloch Institute for Solid State Physics have now come a great deal closer to understanding the actual mechanism in these materials.