Dr. Lang and colleagues found that the presence of an enzyme isoform called α-tryptase, which is encoded by the TPSAB1 gene, correlates with increased prevalence of anaphylaxis or severe reaction to food as compared to subjects without any α-tryptase.

“Determining whether or not a patient with food allergies has α-tryptase can easily be done in clinical practice using a commercially available test to perform genetic sequencing from cheek swabs,” said lead author Abigail Lang, MD, MSc, attending physician and researcher at Lurie Children’s and Assistant Professor of Pediatrics at Northwestern University Feinberg School of Medicine. “If the biomarker is detected, this may help us understand that the child is at a higher risk for a severe reaction or anaphylaxis from their food allergy and should use their epinephrine auto-injector if exposed to the allergen. Our findings also open the door to developing an entirely new treatment strategy for food allergies that would target or block α-tryptase. This is an exciting first step and more research is needed.”

Tryptase is found mainly in mast cells, which are white blood cells that are part of the immune system. Mast cells become activated during allergic reactions. Increased TPSAB1 copy number which leads to increased α-tryptase is already known to be associated with severe reactions in adults with Hymenoptera venom allergy (or anaphylaxis following a bee sting).

Dr. Lang’s study included 119 participants who underwent TPSAB1 genotyping, 82 from an observational food allergy cohort at the National Institute of Allergy and Infectious Diseases (NIAID) and 37 from a cohort of children who reacted to peanut oral food challenge at Lurie Children’s.

“We need to validate our preliminary findings in a much larger study, but these initial results are promising,” says Dr. Lang. “We also still need a better understanding of why and how α-tryptase makes food allergy reactions more severe in order to pursue this avenue for potential treatment.”

Rajesh Kumar, MD, MSc, from Lurie Children’s is the co-senior author on the study. Dr. Kumar is the Interim Division Head of Allergy and Immunology and Professor of Pediatrics at Northwestern University Feinberg School of Medicine.

This work was supported in part by the Midwest Allergy Research Institute (MARI) Food Allergy Pilot Research Award and NIAID-sponsored T32 grant AI083216. This project was funded in part with federal funds from the Division of Intramural Research of the National Institute of Allergy and Infectious Diseases, NIH. This project has also been funded in whole or in part with federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. 75N91019D00024.

In doing so, the method defines the scope of what scientists refer to as the northern Martian paleo-ocean in more detail.

The work was published in July in the journal Icarus, which is affiliated with the American Astronomical Society’s Division for Planetary Sciences.

The research was led by Jaroslav Klokočník, professor emeritus at the Astronomical Institute of the Czech Academy of Sciences. Gunther Kletetschka, associate research professor at the University of Alaska Fairbanks Geophysical Institute, is among the three co-authors. Kletetschka is also affiliated with Charles University in the Czech Republic.

“A lot of people are excited about water on Mars because there may be life forms that once existed on Mars or maybe exist today in some bacterial form,” Kletetschka said. “We can use this gravity approach to look for water on Mars, because we have done it already on Earth.

“In an area of northern Africa, for example, this gravity approach found a shoreline of a long-ago lake, and its finding was consistent with the archaeological evidence indicating a shoreline of that lake,” he said.

The authors write that analyzing the gravity aspects of Mars to better understand the planet improves upon prior approaches. They note that it can “provide complete information with a better insight of the celestial body, applicable in geology, geophysics, hydrology, glaciology and other disciplines.”

The work by Kletetschka and colleagues differs from the traditional approach of mapping a surface based on gravity anomalies alone.

Gravity anomalies are areas of greater or weaker gravitational force exerted by a planetary body’s surface features. A mountain would exert a greater gravitational force because it has a higher concentration of mass than would be expected on a planet without surface features. Ocean basins and trenches would have less gravitational force.

In their Mars research, the authors used a process developed by Klokočník that analyzes gravity aspects calculated from gravity anomaly measurements. Gravity aspects are mathematical products that characterize the gravity anomalies.

They also used topographic data from the Mars Orbital Laser Altimeter instrument aboard NASA’s Mars Global Surveyor, which launched in November 1996 and mapped the planet for 4 ½ years.

Klokočník used that approach to confirm earlier research about the existence of extensive paleolakes or paleoriver systems under the Saharan sands on Earth. His 2017 research paper also suggested a part of the Grand Egyptian Sand Sea as another candidate for a paleolake.

The gravity aspects method has also been used in a comparison of Earth’s geographic features to those of the cloud-shrouded Venus. That research is described in a July 2023 paper in the journal Scientific Reports in which Kletetschka is a co-author.

The results of this research, led by electrical and computer engineering (ECE) professor Joseph Lyding, along with ECE graduate student Pin-Chiao Huang and materials science and engineering graduate student Hongye Sun, were recently published in the journal ACS Nano.

“Graphene has been around for a while and it’s been thought of as something that could potentially be a high-speed electronic material, perhaps even a replacement for silicon,” explains Lyding. “But the problem with graphene itself is that it is not a semiconductor.” Graphene is a one-atom-thick layer of carbon atoms and while it may be the thinnest known material, it is also incredibly strong. Semiconductor properties can be induced in graphene by making it very small or by fabricating it into specific shapes — like ribbons. For this project, atomically-precise GNRs were synthesized by co-author Alexander Sinitskii and his group at the University of Nebraska.

The process of making a transistor out of the GNRs includes putting them on a silicon substrate, connecting wires and running current through the wires to measure the transistor properties. The team has made the critical step of taking the GNRs, that are narrower in diameter than a DNA molecule, and wiring them up. They have developed a technique where the wires are also just a few nanometers wide.

Other researchers have worked on this problem by putting many GNRs on a silicon surface and putting down giant electrodes and hoping for the best. This method, however, introduces a lot of uncertainty. Lyding and his students used a more precise method for wiring up the GNRs. They used a scanning tunneling microscope (an atomic resolution imaging tool) to scan the surface looking for a GNR to use. In STM, a sharp tip is brought close to a surface — on the order of a nanometer — and scanned across the surface. There is a current flow between the tip and the surface, and when the tip comes across atoms on the surface, like driving over a speedbump, that current flow becomes modulated. This allows for the detection and imaging of the GNRs.

Once they find a GNR, they use the electron beam in the STM to trigger metal deposition from hafnium diboride precursor molecules to create the wires. Co-author Gregory Girolami and his group in the UIUC Chemistry Department synthesized the precursor for this process, called STM direct-write. “Our wiring method is very precise. When we see a GNR, we can just define a pattern that we want, and then we’ll connect it. It’s not just blindly throwing electrodes on the surface,” says Huang.

Another advantage of this method is that it is done in ultra-high vacuum (UHV). This ensures that the material stays clean from atmospheric water and other “junk” that degrades device performance.

The researchers also investigated the electronic character of the GNRs and found that it was changed by putting the metal contacts on. Semiconductor “doping” is the intentional introduction of impurities to change its electronic properties. Sun explains, “One way to dope GNRs is to use different chemical reactions to change the GNR properties. But that process is hard. The way we do it is by depositing metal. And we can actually choose the kind of metal that we want to put on the GNRs which could also tune the GNR characteristics. That’s one way to essentially dope our GNRs, without actually using dopants.”

Lyding says, “The next step, which we’re working on now, is to make a real transistor and actually measure the transistor characteristics. But we know that we can do this pristine process, using ultra-high vacuum, of making the electrodes that are absolutely necessary for device function.”