• The research looked at commonly available teabags made using three different compositions of polylactic acid (PLA), which is derived from sources such as corn starch or sugar cane.
• The teabags were buried in soil for seven months, and a range of techniques were then used to assess whether -- and to what extent -- they had deteriorated.
• The study also examined the impacts of the discs cut from the teabags on a species of earthworm, Eisenia fetida, which has a critical role in soil nutrient turnover as it consumes organic matter.
• Researchers found that being exposed to three different concentrations of teabag discs -- equivalent to the mass of half, one and two teabags -- resulted in up to 15% greater mortality, while some concentrations of PLA had a detrimental effect on earthworm reproduction.
• It used analytical techniques such as size exclusion chromatography, nuclear magnetic resonance, and scanning electron microscopy allowing scientists to examine not just how the teabags had changed visibly but also structurally.
• we've shown that when it is not properly disposed of, for example after seven months in the soil, its molecular structure remains intact
• But it is with immense frustration that I see alternative and substitute materials entering the market without clear guidance on how their benefits might be realised. Even if consumers understand how to dispose of these products only around half of households in the UK currently have access to the necessary waste streams for the type of composting required.
• It is essential we learn from the mistakes we made with plastic materials by testing and labelling these novel materials in relation to the prevailing waste management infrastructure.
• "In this study PLA-based teabags did not fully deteriorate, and it seems that composting worms may be harmed by them. The lack of clear labelling can lead to consumers disposing of teabags in their compost, where any limit to complete degradation of the material raises the potential for plastics to enter the soil when compost is added to the garden, with potential impacts on garden wildlife and uptake by food plants."

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• Scientists studying ultra-processed foods have created a new tool for assessing the rewarding and reinforcing properties of foods that make up 58 percent of calories consumed in the United States. The foods have been linked to a wide range of negative health outcomes.
• provides a collection of carefully curated images of minimally processed and ultra-processed foods matched on 26 characteristics, including macronutrients, sodium, dietary fiber, calories, price, and visual characteristics such as a color and portion size

• The scale has its detractors.

   

  "A major criticism of the NOVA scale is that it's difficult to use or that foods are classified differently by different people," said Alexandra DiFeliceantonio, corresponding author and assistant professor at the Fralin Biomedical Research Institute. "We found that people with education in nutrition generally agreed on the food classifications, providing some data that it might not be a valid criticism."
• To develop the picture set, a team of psychologists, neuroscientists, and registered dietitians selected foods to represent either minimally processed or ultra-processed foods.
• The foods were prepared in a lab, visually represented through professional photography, and controlled for consistency. Researchers also gathered price, food weights, and nutritional information -- calories, macronutrients, sodium, and dietary fiber -- for the food in each image.
• researchers recruited 67 nutrition professionals and asked them to classify the foods as minimally or ultra-processed
• "There is very little experimental research on ultra-processed foods, and part of what's been holding us back is better tools for measuring and assessing their effects,"
• The Virginia Tech team is making the pictures and associated data accessible through the Virginia Tech Data Repository of the Virginia Tech University Libraries. This will allow scientists to test hypotheses in behavioral economic and neuroimaging studies.

• Story Source:

   

  Materials provided by Virginia Tech. Original written by Leigh Anne Kelley. Note: Content may be edited for style and length.

• Journal Reference:

   
   
  1. Zach Hutelin, Monica Ahrens, Mary Elizabeth Baugh, Mary E. Oster, Alexandra L. Hanlon, Alexandra G. DiFeliceantonio. Creation and validation of a NOVA scored picture set to evaluate ultra-processed foods.. Appetite, 2024; 198: 107358 DOI: 10.1016/j.appet.2024.107358

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• Ants who receive a caffeine-laced sugary reward become more efficient at navigating back to the reward's location compared to ants that only receive sugar. Researchers report on May 23 in the journal iScience that caffeinated ants move toward the reward via a more direct path but do not increase their speed, suggesting that caffeine improved their ability to learn.
• "The idea with this project was to find some cognitive way of getting the ants to consume more of the poisonous baits we put in the field,"
• it pushes them into having straighter paths and being able to reach the reward faster
• Control efforts, which focus on using poisonous baits, have proven ineffective, likely due to low bait uptake and bait abandonment. The researchers wanted to test whether using caffeine, which has been shown to improve learning in honeybees and bumblebees, might improve the ants' ability to learn the bait location and guide their nestmates back there
• The ants walked down a Lego drawbridge onto a testing platform -- an A4 sheet of paper overlaying an acrylic surface -- on which the researchers had placed a drop of sucrose solution laced with 0, 25 ppm, 250 ppm, or 2,000 ppm of caffeine
• The lowest dose we used is what you find in natural plants, the intermediate dose is similar to what you would find in some energy drinks, and the highest amount is set to be the LD50 of bees -- where half the bees fed this dose die -- so it's likely to be quite toxic for them," says Galante.
• Overall, they tested 142 ants, and each ant was tested four times

• Foraging time dropped by 28% per visit for ants that received 25 ppm of caffeine and by 38% per visit for ants that received 250 ppm of caffeine, meaning that if an ant took 300 s in its first visit, by the final trial, it would be expected to take 113 s at the low caffeine dose and 54 s at the intermediate dose. This effect was not seen at the highest caffeine dose.

   

• The researchers showed that caffeine lowered the ants' foraging times by making them more efficient, not by making them speedier. There was no effect of caffeine on the ants' pace at any dosage, but ants that received low to intermediate doses of caffeine trips traveled by less tortuous paths.

   

  "What we see is that they're not moving faster, they're just being more focused on where they're going," says Galante. "This suggests that they know where they want to go, therefore, they have learned the locations of the reward."
• Henrique Galante, Massimo De Agrò, Alexandra Koch, Stefanie Kau, Tomer J. Czaczkes. Acute exposure to caffeine improves foraging in an invasive ant. iScience, 2024; 109935 DOI: 10.1016/j.isci.2024.109935

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