Friday, February 09, 2024

 

An innovative approach to shield against foodborne illness


The project, led by University of Missouri researchers, is supported by a $5 million grant from the National Science Foundation’s Convergence Accelerator Program.

Grant and Award Announcement

UNIVERSITY OF MISSOURI-COLUMBIA




COLUMBIA, Mo. — Like a silent saboteur, foodborne pathogens can sneak up and ruin your next meal. One of the biggest culprits is salmonella, a type of bacteria found in many foods that causes more than 1.3 million cases of foodborne illnesses annually according to the Centers for Disease Control and Prevention.

Despite nationwide efforts, salmonella’s infection rates have remained nearly unchanged for the past 30 years. Now, MU is part of an interdisciplinary effort determined to change that after recently receiving a three-year, $5 million grant from the National Science Foundation’s Convergence Accelerator program.

The 19-member team of investigators — with expertise in engineering, poultry and food science, public health and supply chain management — is developing new technology to rapidly detect and mitigate salmonella and other foodborne pathogens throughout the entire poultry supply chain.

Rapid results

One in every 25 packages of chicken found on store shelves is contaminated with salmonella, according to the U.S. Food and Drug Administration. Because chicken is a major source of illnesses from salmonella, the researchers decided to begin their efforts by focusing on helping the poultry industry.

The team’s goal is to significantly reduce the risk of foodborne illness in people, said Mahmoud Almasri, lead principal investigator (PI) and an associate professor of electrical engineering and computer science in the MU College of Engineering.

“Real-time data collected from multiple portable sensors will be added to a transformative sensor-enabled decision support system (SENS-D), allowing us to produce results in one hour or less,” Almasri said. “Our rapid results will enable both the supply chain and health partners to make data-driven decisions to enhance food safety, equity and security by providing evidence-based solutions.”

While the current gold standard of testing for foodborne pathogens takes at least 24 hours to produce results, the researchers’ forward-thinking approach could one day revolutionize the poultry industry and influence policy, said Kate Trout, co-PI and an assistant professor of health sciences in the MU College of Health Sciences.

“These pathogens grow very quicky, so a lot can happen to a food product in just 24 hours,” Trout said. “We think our sensors, combined with our decision support system, could change the way that the entire poultry industry and health stakeholders make decisions to ensure a safer food supply for everyone.”

For instance, this research is vital for helping ensure food safety between the packing plant and a store shelf.

“Our project could help increase the understanding of the impact of time and temperature during distribution and transit,” said Tim Safranski, co-PI and a professor of animal sciences in the MU College of Agriculture, Food and Natural Resources and a state swine extension specialist with MU Extension.

The team will also use advanced statistical and machine learning techniques to improve risk mitigation.

“One strength of our project is using advanced analytics and artificial intelligence (AI) to develop innovative descriptive, predictive and prescriptive capabilities for a safe, efficient, equitable and resilient food supply chain,” said Haitao Li, co-PI and a professor and chair of supply chain and analytics department at the University of Missouri-St. Louis.

While the sensors are currently in protype development, the team is already exploring how the new technology might work for detecting other foodborne pathogens besides salmonella.

"We hope our technology can go beyond poultry and be adapted to detect and reduce the risk of other foodborne pathogens to benefit society as a whole,” said Amit Morey, co-PI and an associate professor of poultry science at Auburn University.

When the technology is ready for real-world use, the team will work with MU Extension to help industry partners in Missouri and beyond understand how to use the new tools through various workforce education and training initiatives.

“We know that just developing a new technology and putting it out in the world doesn’t make a large impact unless we teach people in the industry how to use these new AI and detection technologies,” Trout said. “We’re fortunate to have such a strong state extension program to be able to implement that component of the program.”

The team also includes researchers at University of Notre Dame and Lincoln University.

Read more from the National Science Foundation.


Cleaned surfaces may be germ-free, but they’re not bare


Peer-Reviewed Publication

AMERICAN CHEMICAL SOCIETY





Since the outbreak of COVID-19, surfaces in public spaces are cleaned more often. While disinfectant solutions eliminate germs, they don’t leave behind a truly bare surface. They deposit a thin film that doesn’t get wiped up, even after giving the surface a good polish. Researchers reporting in ACS ES&T Air show that residues left by commercial cleaning products contain a wider range of compounds that could impact indoor air quality than previously thought.

Residues on indoor surfaces — like those deposited during cooking or cleaning — may contain compounds that are potentially harmful if absorbed through the skin or if they become airborne and are inhaled. To investigate the impact on indoor air quality, scientists study the gunk that builds up with laboratory models of surfaces. In the models, researchers start with the assumption that a thin film exists on any “clean” surface, but the source and actual makeup of these films is unknown. Because the chemical compositions of commercial cleaning products are different from the products used to prep surfaces in the lab, Rachel O’Brien and colleagues hypothesized that commercial sanitizers could be a missing source for the films. So, they decided to characterize films left behind on recently cleaned surfaces.

Using a surface-indoor solvent extractor, the researchers directly collected films from cleaned surfaces in a controlled lab setting and on regularly washed surfaces in university buildings. This method allowed them to pick up and measure a wide array of compounds, including substances that barely evaporate. In contrast, only semivolatile organic compounds (SVOCs) are picked up by wiping a surface film with a solvent-damp cloth, the typical method used to analyze films. The team’s analyses of the residue samples by mass spectrometry found that:

  • Films from commercial cleaning products were different on the model lab surfaces and university building surfaces and more complex than previously thought.
  • While the composition of the films was different, they all contained SVOCs that can become airborne and impact indoor air quality.
  • This method confirmed the presence of lower volatility surfactants, the primary components of soaps, in residues thought to be from the cleaning solutions. However, surfactants’ effects on surface films have not yet been defined.

As a result of these findings, the researchers say that more compounds could be deposited on cleaned surfaces than had previously been identified. They add that future indoor film studies should use surfaces prepared with commercial cleaning products to more accurately identify how the residues impact indoor air quality. And given the extent and regularity of cleaning done in public spaces and people’s homes, more research is needed to determine the effects of lower volatility compounds on film growth and behavior.

The authors acknowledge funding from the Alfred P. Sloan Foundation.

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The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

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 AUSTERITY KILLS

Low pay is driving primary-care doctors from New Jersey, endangering state residents



RUTGERS UNIVERSITY




A shortage of primary-care doctors endangersUnited States residents in general and New Jerseyans in particular, according to a report co-authored by Alfred Tallia, chair of the Department of Family Medicine and Community Health at Rutgers Robert Wood Johnson Medical School.

“Anyone who has tried to schedule a nonemergency visit understands the problem,” Tallia said. “Existing patients often wait months; others struggle to find a doctor who’s even taking new patients. Lots of people get no care until small problems grow into emergencies.”

“Most of this problem stems from money,” added Tallia. “Primary-care doctors make way less than specialists across the U.S., so we have too few primary-care doctors relative to the number of specialists. Primary-care doctors make even less in New Jersey than in other states, so the ones we train here tend to move elsewhere, and the shortage is worse in New Jersey than in other states.” 

Primary care has been proven to reduce mortality, serious health conditions, population health disparities, and health care costs, Tallia said, yet it remains underfunded, particularly in New Jersey.

According to the report — Primary Care in New Jersey: Findings and Recommendations to Support Advanced Primary Care — slightly less than a third of practicing physicians in the U.S. provide primary care, compared with more than half of physicians in the 38 countries that make up the Organization for Economic Cooperation and Development (OECD). The share of U.S. health care spending devoted to primary care declined from 6.5 percent of total health spending in 2002 to 5.4 percent in 2016 to 4.6 percent in 2020, while such spending remains 7.8 percent or more in other OECD countries.

New Jersey, in turn, underspends on primary care compared with other states. New Jersey Medicaid pays primary-care doctors half of what Medicare pays. Commercial insurers — who pay primary-care providers an average of 120 percent of Medicare rates nationwide — pay an average of 93 percent of Medicare rates in New Jersey. Some small New Jersey practices with little leverage to negotiate higher reimbursement with insurance companies receive 75 percent of Medicare rates. In fact, New Jersey ranks 48th out of the 50 states in primary care spend.

Lower pay leads many primary-care doctors who train in New Jersey to leave the state. New Jersey ranks 10th nationally in primary-care residents and fellows but is 32nd nationally in retaining those people after they complete their training.

According to 2023 survey data from the state Board of Medical Examiners, New Jersey has about 5,300 doctors in the primary-care fields of family medicine, general internal medicine and geriatrics. But half of them work full-time.

The report, compiled for the New Jersey Health Care Quality Institute by representatives from health care providers and insurers, recommends three major steps to end the shortage and help New Jersey residents gain easy access to primary care that should help them live longer and healthier lives.

The state should:

  • Raise Medicaid reimbursement rates for primary care to Medicare levels and direct Medicaid Managed Care Organizations to do likewise.
  • Use its regulatory power to begin shifting doctor compensation from the historical fee-for-service model and toward an advanced primary-care model, where doctors get money to keep patients well rather than simply treating them when they are sick.
  • Better track caregiver numbers and medical expenditures and use the data to track improvements.

Tallia said the effort to move from fee-for-service to advanced primary care echoes a major national report authored by a group that included Rutgers Health Vice Chancellor Shawna Hudson that aims to extend U.S. lives “by bringing our primary care practices into line with those in countries where people are much healthier than they are here.”

“The other recommendations are New Jersey specific, and they can ease the worst of the problems here in New Jersey,” Tallia added. “We’ve seen several other states, including Oregon, Massachusetts and Rhode Island, work to ease major primary care shortages by adjusting rates.”

 SPACE

Researchers discover cosmic dust storms from Type Ia supernova


Peer-Reviewed Publication

CHINESE ACADEMY OF SCIENCES HEADQUARTERS


Cosmic dust—like dust on Earth—comprises groupings of molecules that have condensed and stuck together in a grain. But the exact nature of dust creation in the universe has long been a mystery. Now, however, an international team of astronomers from China, the United States, Chile, the United Kingdom, Spain, etc., has made a significant discovery by identifying a previously unknown source of dust in the universe: a Type Ia supernova interacting with gas from its surroundings.  

The study was published in Nature Astronomy on Feb. 9, and was led by Prof. WANG Lingzhi from the South America Center for Astronomy of the Chinese Academy of Sciences. 

Supernovae have been known to play a role in dust formation, and to date, dust formation has only been seen in core-collapse supernovae—the explosion of massive stars. Since core-collapse supernovae do not occur in elliptical galaxies, the nature of dust creation in such galaxies has remained elusive. These galaxies are not organized into a spiral pattern like our Milky Way but are giant swarms of stars. This study shows that thermonuclear Type Ia supernovae, the explosion of white dwarf stars in binary systems with another star, may account for a significant amount of dust in these galaxies. 

The researchers monitored a supernova, SN 2018evt, for over three years using space-based facilities like NASA’s Spitzer Space Telescope and NEOWISE missions, ground-based facilities like the Las Cumbres Observatory’s global network of telescopes, and other facilities in China, South America, and Australia. They found that the supernova was running into material previously cast off by one or both stars in the binary system before the white dwarf star exploded, and the supernova sent a shock wave into this pre-existing gas.  

During more than a thousand days of monitoring the supernova, the researchers noticed that its light began to dim precipitously in the optical wavelengths that our eyes can see and then started glowing brighter in infrared light. This was a telltale sign that dust was being created in the circumstellar gas after it cooled following the supernova shock wave passing through it. 

"The origins of cosmic dust have long been a mystery. This study marks the first detection of a significant and rapid dust formation process in the thermonuclear supernova interacting with circumstellar gas," said Prof. WANG, first author of the study. 

The study estimated that a large amount of dust must have been created by this one supernova event—an amount equal to more than 1% of the Sun's mass. As the supernova cools, the amount of dust created should increase, perhaps tenfold. While these dust factories are not as numerous or efficient as core-collapse supernovae, there may be enough of these thermonuclear supernovae interacting with their surroundings to be a significant or even dominant source of dust in elliptical galaxies. 

"This study offers insights into the contribution of thermonuclear supernovae to cosmic dust, and more such events may be expected to be found in the era of the James Webb Space Telescope (JWST)," said Prof. WANG Lifan from Texas A&M University, a co-first author of the study. The Webb telescope sees infrared light that is perfect for the detection of dust. 

"The creation of dust is just gas getting cold enough to condense," said Prof. Andy Howell from Las Cumbres Observatory and the University of California Santa Barbara. Howell is the Principal Investigator of the Global Supernova Project whose data was used in the study. "One day that dust will condense into planetesimals and, ultimately, planets. This is creation starting anew in the wake of stellar death. It is exciting to understand another link in the circle of life and death in the universe."

Migration solves exoplanet puzzle


Simulations provide a potential explanation for the mysterious gap in the size distribution of super-Earths.



MAX PLANCK INSTITUTE FOR ASTRONOMY

Artistic representation of an exoplanet whose water ice on the surface is increasingly vaporizing and forming an atmosphere during its approach to the central star of the planetary system 

IMAGE: 

ARTISTIC REPRESENTATION OF AN EXOPLANET WHOSE WATER ICE ON THE SURFACE IS INCREASINGLY VAPORIZING AND FORMING AN ATMOSPHERE DURING ITS APPROACH TO THE CENTRAL STAR OF THE PLANETARY SYSTEM. THIS PROCESS INCREASES THE MEASURED PLANETARY RADIUS COMPARED TO THE VALUE THE PLANET WOULD HAVE AT ITS PLACE OF ORIGIN.

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CREDIT: THOMAS MÃœLLER (MPIA)




Ordinarily, planets in evolved planetary systems, such as the Solar System, follow stable orbits around their central star. However, many indications suggest that some planets might depart from their birthplaces during their early evolution by migrating inward or outward. This planetary migration might also explain an observation that has puzzled researchers for several years: the relatively low number of exoplanets with sizes about twice as large as Earth, known as the radius valley or gap. Conversely, there are many exoplanets smaller and larger than this size.

Six years ago, a reanalysis of data from the Kepler space telescope revealed a shortage of exoplanets with sizes around two Earth radii,” Remo Burn explains, an exoplanet researcher at the Max Planck Institute for Astronomy (MPIA) in Heidelberg. He is the lead author of the article reporting the findings outlined in this article, now published in Nature Astronomy.

Where does the radius valley come from?

In fact, we – like other research groups – predicted based on our calculations, even before this observation, that such a gap must exist,” explains co-author Christoph Mordasini, a member of the National Centre of Competence in Research (NCCR) PlanetS. He heads the Division of Space Research and Planetary Sciences at the University of Bern. This prediction originated during his tenure as a scientist at MPIA, which has been jointly researching this field with the University of Bern for many years.

The most commonly suggested mechanism to explain the emergence of such a radius valley is that planets might lose a part of their original atmosphere due to the irradiation from the central star – especially volatile gases like hydrogen and helium. “However, this explanation neglects the influence of planetary migration,” Burn clarifies. It has been established for about 40 years that under certain conditions, planets can move inward and outward through planetary systems over time. How effective this migration is and to what extent it influences the development of planetary systems impacts its contribution to forming the radius valley.

Enigmatic sub-Neptunes

Two different types of exoplanets inhabit the size range surrounding the gap. On one hand, there are rocky planets, which can be more massive than Earth and are hence called super-Earths. On the other hand, astronomers are increasingly discovering so-called sub-Neptunes (also mini-Neptunes) in distant planetary systems, which are, on average, slightly larger than the super-Earths.

However, we do not have this class of exoplanets in the Solar System,” Burn points out. “That’s why, even today, we’re not exactly sure about their structure and composition.

Still, astronomers broadly agree that these planets possess significantly more extended atmospheres than rocky planets. Consequently, understanding how these sub-Neptunes’ characteristics contribute to the radius gap has been uncertain. Could the gap even suggest that these two types of worlds form differently?

Wandering ice planets

Based on simulations we already published in 2020, the latest results indicate and confirm that instead, the evolution of sub-Neptunes after their birth significantly contributes to the observed radius valley,” concludes Julia Venturini from Geneva University. She is a member of the PlanetS collaboration mentioned above and led the 2020 study.

In the icy regions of their birthplaces, where planets receive little warming radiation from the star, the sub-Neptunes should indeed have sizes missing from the observed distribution. As these presumably icy planets migrate closer to the star, the ice thaws, eventually forming a thick water vapour atmosphere.

This process results in a shift in planet radii to larger values. After all, the observations employed to measure planetary radii cannot differentiate whether the determined size is due to the solid part of the planet alone or an additional dense atmosphere.

At the same time, as already suggested in the previous picture, rocky planets ‘shrink’ by losing their atmosphere. Overall, both mechanisms produce a lack of planets with sizes around two Earth radii.

Physical computer models simulating planetary systems

The theoretical research of the Bern-Heidelberg group has already significantly advanced our understanding of the formation and composition of planetary systems in the past,” explains MPIA Director Thomas Henning. “The current study is, therefore, the result of many years of joint preparatory work and constant improvements to the physical models.

The latest results stem from calculations of physical models that trace planet formation and subsequent evolution. They encompass processes in the gas and dust disks surrounding young stars that give rise to new planets. These models include the emergence of atmospheres, the mixing of different gases, and radial migration.

 “Central to this study were the properties of water at pressures and temperatures occurring inside planets and their atmospheres,” explains Burn. Understanding how water behaves over a wide range of pressures and temperatures is crucial for simulations. This knowledge has been of sufficient quality only in recent years. It is this component which permits realistic calculation of the sub-Neptunes’ behaviour, hence explaining the manifestation of extensive atmospheres in warmer regions.

It’s remarkable how, as in this case, physical properties on molecular levels influence large-scale astronomical processes such as the formation of planetary atmospheres,” Henning adds.

If we were to expand our results to cooler regions, where water is liquid, this might suggest the existence of water worlds with deep oceans,” Mordasini says. “Such planets could potentially host life and would be relatively straightforward targets for searching for biomarkers thanks to their size.

Further work ahead

However, the current work is just an important milestone. Although the simulated size distribution closely matches the observed one, and the radius gap is in the right place, the details still have some inconsistencies. For instance, too many ice planets end up too close to the central star in the calculations. Nonetheless, researchers do not perceive this circumstance as a disadvantage but hope to learn more about planetary migration in this way.

Observations with telescopes like the James Webb Space Telescope (JWST) or the under-construction Extremely Large Telescope (ELT) could also assist. They would be capable of determining the composition of planets depending on their size, thus providing a test for the simulations described here.

Background information

The MPIA scientists involved in this study are Remo Burn and Thomas Henning.

Other researchers include Christoph Mordasini (University of Bern, Switzerland [Unibe]), Lokesh Mishra (Université de Genève, Switzerland [Unige], and Unibe), Jonas Haldemann (Unibe), Julia Venturini (Unige), and Alexandre Emsenhuber (Ludwig Maximilian University Munich, Germany, and Unibe).

The NASA Kepler space telescope searched for planets around other stars between 2009 and 2018 and discovered thousands of new exoplanets during its operation. It utilised the transit method: when a planet’s orbit is inclined in a way that the plane lies within the telescope’s line of sight, planets periodically block part of the star’s light during their orbit. This periodic fluctuation in the star’s brightness enables an indirect detection of the planet and determination of its radius.


Size distribution of observed and simulated exoplanets with radii smaller than five Earth radii