Decomposition under the microscope

Lara Indra photographically documenting an animal cadaver. Attached to the tree trunk and behind the researcher are camera traps; an insect trap is positioned to the left.
Photo Credit: Sandra Lösch / Dept. of Anthropology, IRM, University of Bern

Researchers at the University of Bern have investigated the process of decomposition on pig carcasses left in nature. The researchers discovered that the previous standard method for assessing decomposition in Switzerland needs to be adapted – with an impact on forensic analysis. The method presented by the researchers aims to better determine the post-mortem interval.

A dead body decomposes with the help of various organisms – such as intestinal bacteria, flies, maggots and beetles. This makes it difficult to establish the post-mortem interval of cadavers in forensics: the more advanced the decomposition, the harder it is to determine the time of death. Therefore, various methods have the goal of correlating the degree of decomposition with the postmortem interval. With respect to this, the body is divided into three areas – the head and neck, the trunk and the extremities – and its condition is assessed using a point value system. The findings from the three areas are then added together, resulting in the total body score (TBS). 

Researchers provide unprecedented view into aerosol formation in Earth’s lower atmosphere

Researchers identified evidence of Criegee intermediate oligomerization in the Amazon rainforest.
 Image Credit: Argonne National Laboratory

Eighty-five percent of the Earth’s air resides in the lowest layer of its atmosphere, or troposphere. Yet, major gaps remain in our understanding of the atmospheric chemistry that drives changes in the troposphere’s composition.

One especially important gap in knowledge is the formation and prevalence of secondary organic aerosols (SOAs), which impact the planet’s radiation balance, air quality and human health. But that gap is closing — due to the groundbreaking discoveries of an international team of researchers led by the U.S. Department of Energy’s (DOE) Argonne National Laboratory, Sandia National Laboratories and NASA’s Jet Propulsion Laboratory (JPL).

The scientists detail their findings in a new paper published in Nature Geosciences. 

The team focused on a class of compounds known as Criegee intermediates (CIs). Researchers suspect that CIs play a critical role in the formation of SOAs when they combine via a process called oligomerization. But no one had ever directly identified the chemical signatures of this process in the field — until now.

Can ‘Super Volcanoes’ Cool the Earth in a Major Way? A New Study Suggests No.

Quizapu Volcano, Chile
Photo Credit: Kevin Krajick / Earth Institute

Some 74,000 years ago, the Toba volcano in Indonesia exploded with a force 1,000 times more powerful than the 1980 eruption of Mount St. Helens. The mystery is what happened after that.

When it comes to the most powerful volcanoes, researchers have long speculated how post-eruption global cooling—sometimes called volcanic winter—could potentially pose a threat to humanity after a so-called super eruption. Previous studies have agreed that some planet-wide cooling would occur, but they have diverged on how much. Estimates have ranged from 3.6 to 14 degrees F (2 to 8 degrees C).

In a new study published in the Journal of Climate, a team from NASA’s Goddard Institute for Space Studies, an affiliate of the Columbia Climate School, used advanced computer modeling to simulate super eruptions like the Toba event. They found that post-eruption cooling would probably not exceed 2.7 degrees F (1.5 C) for even the most powerful blasts.

“The relatively modest temperature changes we found most compatible with the evidence could explain why no single super eruption has produced firm evidence of global-scale catastrophe for humans or ecosystems,” said lead author Zachary McGraw, a postdoctoral researcher at Goddard and Columbia.

To qualify as a super eruption, a volcano must release more than 240 cubic miles (1,000 cubic kilometers) of magma. These eruptions are extremely powerful, and rare. The most recent super eruption occurred more than 22,000 years ago in New Zealand. The best-known example may be the eruption that blasted Yellowstone Crater in Wyoming about 2 million years ago.

Earliest-yet Alzheimer’s biomarker found in mouse model could point to new targets

Illinois graduate student Yeeun Yook, left, and professor Nien-Pei Tsai worked with their team to find the earliest marker of Alzheimer’s disease yet reported in the brains of mice. The work could create new targets for early detection or treatment options.
Photo Credit: Fred Zwicky

A surge of a neural-specific protein in the brain is the earliest-yet biomarker for Alzheimer’s disease, report University of Illinois Urbana-Champaign researchers studying a mouse model of the disease. Furthermore, the increased protein activity leads to seizures associated with the earliest stages of neurodegeneration, and inhibiting the protein in the mice slowed the onset and progression of seizure activity. 

The neural-specific protein, PSD-95, could pose a new target for Alzheimer’s research, early diagnosis and treatment, said study leader Nien-Pei Tsai, an Illinois professor of molecular and integrative physiology. 

Tsai’s group studies mice that make more of the proteins that form amyloid-beta, which progressively aggregates in Alzheimer’s disease to form plaques in the brain that hamper neural activity. However, in the new work, the group focused on a time frame much earlier in the mouse lifespan than others have studied – when no other markers or abnormalities have been reported, Tsai said.

Aluminum nanoparticles make tunable green catalysts

Aaron Bayles is a Rice University doctoral alum, a postdoctoral researcher at the National Renewable Energy Laboratory and a lead author on a paper published in the Proceedings of the National Academy of Sciences.
Photo Credit: Courtesy of Aaron Bayles / Rice University

Catalysts unlock pathways for chemical reactions to unfold at faster and more efficient rates, and the development of new catalytic technologies is a critical part of the green energy transition.

The Rice University lab of nanotechnology pioneer Naomi Halas has uncovered a transformative approach to harnessing the catalytic power of aluminum nanoparticles by annealing them in various gas atmospheres at high temperatures.

According to a study published in the Proceedings of the National Academy of Sciences, Rice researchers and collaborators showed that changing the structure of the oxide layer that coats the particles modifies their catalytic properties, making them a versatile tool that can be tailored to suit the needs of different contexts of use from the production of sustainable fuels to water-based reactions.

“Aluminum is an earth-abundant metal used in many structural and technological applications,” said Aaron Bayles, a Rice doctoral alum who is a lead author on the paper. “All aluminum is coated with a surface oxide, and until now we did not know what the structure of this native oxide layer on the nanoparticles was. This has been a limiting factor preventing the widespread application of aluminum nanoparticles.”

Aluminum nanoparticles absorb and scatter light with remarkable efficiency due to surface plasmon resonance, a phenomenon that describes the collective oscillation of electrons on the metal surface in response to light of specific wavelengths. Like other plasmonic nanoparticles, the aluminum nanocrystal core can function as a nanoscale optical antenna, making it a promising catalyst for light-based reactions.

Juno Spacecraft Measures Oxygen Production on Jupiter's Moon, Europa

For the first time, SwRI scientists used the Jovian Auroral Distributions Experiment (JADE) instrument to definitively detect oxygen and hydrogen in the atmosphere of one of Jupiter's largest moons, Europa. NASA's Juno spacecraft, using its SwRI-developed instrument, made the measurements during a 2022 flyby of Europa.
Image Credit: Courtesy of NASA/JPL/University of Arizona

NASA’s Juno spacecraft has directly measured charged oxygen and hydrogen molecules from the atmosphere of one of Jupiter’s largest moons, Europa. According to a new study co-authored by SwRI scientists and led by Princeton University, these observations provide key constraints on the potential oxygenation of its subsurface ocean.

“These findings have direct implications on the potential habitability of Europa,” said Juno Principal Investigator Dr. Scott Bolton of SwRI, a co-author of the study. “This study provides the first direct in-situ measurement of water components existing in Europa’s atmosphere, giving us a narrow range that could support habitability.”

In 2022, Juno completed a flyby of Europa, coming as close as 352 kilometers to the moon. The SwRI-developed Jovian Auroral Distributions Experiment (JADE) instrument aboard Juno detected significant amounts of charged molecular oxygen and hydrogen lost from the atmosphere.

Harmful ‘forever chemicals’ removed from water with new electrocatalysis method

Per- and polyfluoroalkyl substances (PFAS) are often referred to as “forever chemicals” because they break down very slowly. Rochester scientists have developed nanocatalysts that can more affordably remediate a specific type of PFAS called Perfluorooctane sulfonate (PFOS).
Photo Credit: J. Adam Fenster / University of Rochester 

A novel approach using laser-made nanomaterials created from nonprecious metals could lay the foundation for globally scalable remediation techniques.

Scientists from the University of Rochester have developed new electrochemical approaches to clean up pollution from “forever chemicals” found in clothing, food packaging, firefighting foams, and a wide array of other products. A new Journal of Catalysis study describes nanocatalysts developed to remediate per- and polyfluoroalkyl substances, known as PFAS.

The researchers, led by assistant professor of chemical engineering Astrid Müller, focused on a specific type of PFAS called Perfluorooctane sulfonate (PFOS), which was once widely used for stain-resistant products but is now banned in much of the world for its harm to human and animal health. PFOS is still widespread and persistent in the environment despite being phased out by US manufacturers in the early 2000s, continuing to show up in water supplies.

How Does a River Breathe?

Scientists at Pacific Northwest National Laboratory have been studying processes that affect how rivers and streams breathe, particularly in the Columbia River Basin, to help prepare for future changes related to water quality and climate change. 
Photo Credit: Andrea Starr | Pacific Northwest National Laboratory

Take a deep breath.

Pay attention to how air moves from your nose to your throat before filling your lungs with oxygen.

As you exhale your breath, a mix of oxygen and carbon dioxide leaves your nose and mouth.

Did you know that streams and rivers “breathe” in a similar way?

The United States is home to more than 250,000 of these flowing bodies of water that connect to coastal zones and oceans. They vary in size, from small streams to large rivers, but all take in oxygen and give off carbon dioxide and other greenhouse gases like methane. 

Over recent years, a team of scientists led by Pacific Northwest National Laboratory (PNNL) has been immersed in crucial research around the processes and interactions that contribute to greenhouse gas dynamics. Their work focuses on whole networks of streams and rivers, as well as the land surrounding these systems.       

Their work also includes factors that can disturb how streams and rivers breathe. Some of these disturbances happen beyond streams, like wildfires, but still impact how streams breathe by changing how material enters streams. Understanding these impacts is key to addressing challenges related to water quality, global carbon cycling, and climate change.

Possible ‘Trojan Horse’ found for treating stubborn bacterial infections

Transmission electron microscope (TEM) image of the bacterial cell with an extracellular vesicle attached.
Image Credit: Courtesy of Washington State University

Bacteria can be tricked into sending death signals to stop the growth of their slimy, protective homes that lead to deadly infections, a new study demonstrates.

The discovery by Washington State University researchers could someday be harnessed as an alternative to antibiotics for treating difficult infections. Reporting in the journal Biofilm, the researchers used the messengers, which they named death extracellular vesicles (D-EVs), to reduce growth of the bacterial communities by up to 99.99% in laboratory experiments.

“Adding the death extracellular vesicles to the bacterial environment, we are kind of cheating the bacteria cells,” said Mawra Gamal Saad, first author on the paper and a graduate student in WSU’s Gene and Linda Voiland School of Chemical Engineering and Bioengineering. “The cells don’t know which type of EVs they are, but they take them up because they are used to taking them from their environment, and with that, the physiological signals inside the cells change from growth to death.”

A Larger Area of Arctic Seafloor is Exposed to Sunlight

Photo Credit: © Ignacio Garrido

Most of the sunlight reaching the Arctic Ocean is reflected by sea ice, shielding ocean ecosystems from light. As Arctic sea ice continues to melt, larger areas of the ocean and seafloor become exposed to sunlight, potentially allowing more photosynthesis to occur and making the Arctic Ocean more productive. However, this does not seem to be occurring uniformly across the Arctic Ocean.

Over the past 25 years, the amount of summer Arctic sea ice has diminished by more than 1 million square kilometers. As a result, vast areas of the Arctic Ocean are now, on average, ice free in summer. Scientists are closely monitoring how this impacts sunlight availability and marine ecosystems in the far north.

Many questions arise when such large areas become ice-free and can receive sunlight. A prevailing paradigm suggests that the Arctic Ocean is rapidly becoming more productive as sunlight becomes more abundant in the marine environment. However, it is unclear how ecosystems will evolve in response to increasing sunlight availability and how different parts of the marine ecosystem will be affected, says Karl Attard, a marine scientist and Associate Professor at the Department of Biology.

Attard has led an international research team investigating sunlight availability and photosynthetic production on the understudied Arctic seafloor. Their study has been published in the scientific journal Proceedings of the National Academy of Sciences (PNAS).