Tag: PLOS

Categories : UncategorizedTags : Leave a comment

Neanderthals May Have Used Birch Tar for Its Anti-bacterial Properties

On By ModernMedia

Experiments confirm anti-biotic properties of birch bark extract

The bark of birch trees has been used to produce tar for more than 150 000 years. The centre photo shows birch bark tar condensed onto a rock that borders a hearth. When scraped off the rocks, the viscous tar can be used as both an adhesive and antibiotic.

Neanderthals probably used birch tar for multiple functions, including treating their wounds, according to a study published March 18, 2026 in the open-access journal PLOS One by a team of researchers led by Tjaark Siemssen of the University of Cologne, Germany, and the University of Oxford, UK.

Birch tar is commonly found at Neanderthal archaeological sites, and in some cases this tar is known to have been used as an adhesive to assemble tools. Recently, some researchers have raised the question of whether Neanderthals had multiple uses for this substance. For instance, Indigenous communities in northern Europe and Canada use birch tar to treat wounds, and there is growing evidence that Neanderthals also employed a variety of medical practices.

To investigate the medicinal potential of birch tar, Siemssen and colleagues extracted tar from modern birch tree bark, specifically targeting species known from Neanderthal sites. They used multiple extraction methods, including distillation of tar in a clay pit and condensation of tar against a stone surface, both of which would have been methods available to Neanderthals. When exposed to different strains of bacteria, all of the tar samples were found to be effective at hindering the growth of Staphylococcus bacteria known to cause wound infections.

These experiments not only support the efficacy of Indigenous medicinal practices, but also reinforce the possibility that Neanderthals used birch tar to treat wounds. The authors note that there are other potential uses of birch tar, such as insect repellent, as well as other plants to which Neanderthals had access. Further exploration of the multiple potential uses of these natural ingredients will enable a more thorough understanding of Neanderthal culture.

The authors add: “We found that the birch tar produced by Neanderthals and early humans had antibacterial properties. This has important implications for how Neanderthals may have mitigated disease burden during the last Ice Ages, and adds to a growing set of evidence on healthcare in these early human communities.”

“By bringing together research on indigenous pharmacology and experimental archaeology, we begin to understand the medicinal practices of our distant human ancestors and their closest cousins. Additionally, this study of ‘palaeopharmacology’ can contribute to the rediscovery of antibiotic remedies whilst we face an ever more pressing antimicrobial resistance crisis.”

“The messiness of birch tar production deserves a special mention. Every step of the production is a sensory experience in itself, and getting the tar off our hands after spending hours at the fire has been a challenge every time.”

Provided by PLOS

Press preview: https://plos.io/3P6QrS5

In your coverage, please use this URL to provide access to the freely available article in PLOS One: https://plos.io/4le9beh

Contact: Tjaark Siemssen, tjaark.siemssen@arch.ox.ac.uk

Image caption: The bark of birch trees has been used to produce tar for more than 150,000 years. The centre photo shows birch bark tar condensed onto a rock that borders a hearth. When scraped off the rocks, the viscous tar can be used as both an adhesive and antibiotic.

Image credit: Tjaark Siemssen, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

High-resolution image link: https://plos.io/4cteLHD

Citation: Siemssen T, Oludare A, Schemmel M, Puschmann J, Bierenstiel M (2026) Antibacterial properties of experimentally produced birch tar and its medicinal affordances in the Pleistocene. PLoS One 21(3): e0343618. https://doi.org/10.1371/journal.pone.0343618

Author countries: U.K., Canada, Belgium, Germany

Funding: Tjaark Siemssen is funded by the Boise Trust of the University of Oxford and the German Academic Scholarship Foundation (Studienstiftung). Aderonke Oludare was funded by Canadian Institutes of Health Research (CIHR) Project Grant 420598 awarded to Matthias Bierenstiel. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Categories : ExerciseTags :

Urban and Rural Residents Engage in Different Kinds of Physical Activity

On By ModernMedia

In new study, rural and urban residents differed in the types of physical activity they do the most

Photo by Azat Satlykov on Unsplash

In a study of US adults, walking was, by far, the most popular leisure-time physical activity, while rural residents also enjoyed gardening, hunting and fishing, and urban residents more commonly reported running, weightlifting and dance. Urban residents were more likely than rural residents to meet physical activity guidelines. Christiaan Abildso of West Virginia University, US, and colleagues present these findings in the open-access journal PLOS One on April 1, 2026.

The US Department of Health and Human Services publishes guidelines on recommended amounts of aerobic and muscle-strengthening physical activity for adults. While the overall proportion of U.S. adults meeting these guidelines has increased in recent decades, certain populations are less likely to meet them, including adults living in rural areas. Understanding differences in preferred recreational physical activities could help inform efforts to reduce such disparities.

However, few studies have examined urban versus rural preferences for leisure-time physical activities, and how they relate to meeting guidelines. To address that gap, Abildso and colleagues analysed telephone survey data collected from a national sample of 396 261 U.S. adults in 2019.

Out of 75 survey options for leisure-time physical activities, walking was the most popular among both urban and rural adults, with 44.1% reporting walking as the activity they spent the most time doing. This finding echoes a similar study of U.S. data collected in 2011, which also found walking to be the top activity. However, further analysis of the 2019 data showed that even among walkers, only 25% met combined guidelines for aerobic and muscle-strengthening physical activity, and about 22% did not meet either guideline.

The popularity of other activities varied. For instance, rural residents reported higher rates of gardening, hunting, fishing, and farm work, while urban residents had higher participation in running, weightlifting, bicycling, and dance. However, in general, rural adults were more likely to be inactive and less likely to meet guidelines for aerobic or muscle-strengthening physical activity.

These findings could help inform efforts to boost physical activity by tailoring solutions to be more culturally and demographically appropriate. The researchers also call for a similar analysis of more recently collected data, as habits may have shifted during the COVID-19 pandemic.

Christiaan Abildso adds: “We expected to see that walking would continue to be the most common physical activity. However, it was surprising to see that nearly 1 in 4 adults who walk as their main activity did not meet either of the physical activity guidelines. That is, they reported less than the recommended 150 minutes per week of moderate-intensity aerobic activity and less than the recommended 2 days per week of muscle strengthening activity, such as yoga or exercises with resistance bands.”

“What we might be seeing in these rural-urban differences in preferences may just reflect what people have access to or what is culturally supported. In our work, we see a need to continue to support our partners in small towns and rural places by creating physical, social, and cultural conditions that support physical activity. This could mean creating a wide shoulder on a country road for running and cycling, helping a senior centre with their chair exercise programming, creating or improving park spaces, expanding the national network of rail-trails, renovating abandoned and dilapidated structures (Brownfields) into viable activity centres, keeping school facilities open to the public, and many other strategies. Everyone needs to ask, ‘how does what we’re doing affect physical activity,’ in order to help get people more active, more often, in more places.”

Provided by PLOS

Categories : Diet and NutritionTags :

Sugary Drink Taxes May Not Be Effective in Fast-food Settings

On By ModernMedia

Analysis of nearly 7 billion Taco Bell transactions finds sugary drink taxes not linked to lower beverage calorie purchases

Photo by Breakingpic on Pexels

Taxes on sugary drinks had no effect on beverage calorie purchases from fast-food chain restaurants in the U.S., according to a new study by Brian Elbel and Pasquale Rummo from NYU Grossman School of Medicine and colleagues publishing April 2nd in the open-access journal PLOS Medicine.

Sugary drink taxes have been adopted in several U.S. jurisdictions as a public health strategy to curb sugar consumption and improve dietary behaviors. Research on the impact of these taxes on grocery stores purchases attribute sugary drink taxes to an estimated 15% decrease in sales. However, whether this translates to an impact in restaurant sales has not been well studied.

Researchers analyzed six years of sales data (2015–2020) from more than 7,300 Taco Bell locations nationwide, focusing on drive‑through purchases. The study compared beverage calories per transaction at 60 restaurants across five jurisdictions with sugary drink taxes—Albany, California; Cook County, Illinois; Oakland, California; Philadelphia, Pennsylvania; and Seattle, Washington—with a matched group of similar restaurants in areas without such taxes.

Overall, the analysis found no significant association between sugary drink taxes and beverage calories per transaction, suggesting that sugary drink taxes of this size or alone may not substantially reduce beverage calorie consumption in fast food restaurant settings.

The authors note that consumer behaviour in restaurants—such as choosing combo meals or prioritising convenience—may limit the effectiveness of these policies.

Elbel adds, “Using millions of transactions from six years of sales data, we found that sugary beverage taxes did not influence beverage calories when implemented in five cities in the U.S.”

Rummo notes, “These results suggest that sugary drink taxes may not be effective in reducing beverage calorie consumption in fast food restaurants, as compared to supermarkets. This could be because the sizes of sugary drink taxes in the U.S. are too small for consumers or that they just aren’t responsive to price changes in these settings, among other reasons.”

Provided by PLOS

Categories : Obstetrics & GynaecologyTags :

Yawns in Healthy Foetuses Might Indicate Mild Distress

On By ModernMedia

Foetuses yawn in the womb, with more yawns associated with a lower weight at birth

Photo by Mart Production on Pexels

Even in the womb, where all oxygen is provided by the parental placenta, foetuses can – and do – yawn. More yawns during observation were associated with a lower weight at birth – potentially indicating mild foetal stress in the womb, according to a study published February 25, 2026 in the open-access journal PLOS One by Damiano Menin, of the Università degli Studi di Ferrara in Italy, and colleagues.

Yawning is a behaviour found across vertebrates – and no one quite knows why. In humans, foetuses yawn in the womb from about 11 weeks. Even though there is no air to breathe, they slowly open their mouths, make motions similar to inhalation and exhalation, and close their mouths again. To understand more about foetal yawns, the authors of this study used ultrasound to observe 32 healthy foetuses (56% female, 44% male) between 23 and 31 weeks. Each foetus was observed for 22.5 minutes.

The authors found that the foetuses yawned between zero and six times during the observation period, with an average of 3.63 yawns per hour. They also showed that foetuses that yawned more during their observations were more likely to have a low weight at birth, which is considered as an indicator of mild distress – though all foetuses in the study were born healthy.

The researchers did not perform any manipulations to see if they could affect foetal yawning and also did not record measures such as foetal heart rate or maternal temperature which might potentially be associated with the behaviour. Additionally, no high-risk pregnancies were observed. Based on their research, the authors suggest that frequent foetal yawning might be a sign of mild distress in the healthy foetus.

The authors add: “We found that yawning frequencies in the womb are negatively related to birth weight, potentially indicating a stress-related response in healthy fetuses. This suggests that even before birth, yawning may serve as an indicator of a foetus’s well-being.”

Provided by PLOS

Categories : Respiratory DiseasesTags :

Shorter Treatment Regimens are Safe Options for Preventing Active Tuberculosis

On By ModernMedia

One- and three-month regimens both had few adverse reactions and high rates of completion

Tuberculosis bacteria. Credit: CDC

A study comparing one- and three-month antibiotic treatments to prevent active tuberculosis (TB) finds that a high percentage of patients successfully completed both regimens and suffered few adverse side effects. A team led by Richard Chaisson, of the Johns Hopkins School of Medicine, reports these findings February 10th in the open access journal PLOS Medicine.

Following TB exposure, the World Health Organization has traditionally recommended six to nine months of antibiotic treatment to prevent an active infection from developing, but many individuals fail to complete the long course of medication. Studies have shown that shorter regimens lasting one and three months are effective at preventing TB, but the one-month treatment had only been tested in people living with HIV, and the safety of the two regimens had not been compared in a head-to-head trial.

Researchers performed a clinical trial in 500 people residing in Brazil, who were not living with HIV and had been exposed to TB. They randomly assigned participants to take two antibiotics, isoniazid and rifapentine, daily for one month, or weekly for three months. Both the one- and three-month regimens had similarly high rates of completion, at 89.6% and 84.1%, respectively. Adverse reactions were typically mild or moderate, and occurred at comparable rates in both groups. Both regimens were deemed successful and neither proved superior to the other.

Expanding the number of people who receive preventive therapy is essential for reducing TB infections globally, but these efforts have been hampered by several factors, including the length of the treatments. The new findings provide evidence that a one-month course of antibiotics is safe for patients, regardless of HIV status, and will help clinicians, public health programs, and patients to make informed choices about which regimens to use. Experts hope the success of shorter treatments, combined with the availability of newer generic formulations of the medications, which can be taken at home, will facilitate broader use of preventive therapy for TB.

The authors add, “Prevention of tuberculosis in people at the greatest risk is essential for global control of the disease, and shorter preventive treatment regimens will be instrumental in catalyzing uptake in high-burden countries.”

“Tuberculosis preventive treatment regimens have now been shortened from 6-9 months of daily medication to 1 month of daily treatment or 12 once-weekly doses, a transformational advance. Our study shows that both of the ultra-short regimens are well-tolerated and have high rates of completion.”

“The high rates of treatment completion and excellent safety profile of the short-course regimens will help Brazil and other high-burden countries achieve TB control by facilitating widespread uptake of TB preventive treatment,” states coauthor Betina Durovni.

“Preventing TB with short courses of well-tolerated medicines ensures that millions more people around the world can be protected from the devastating consequences of TB disease,” says coauthor Marcelo Cordeiro-Santos.

Provided by PLOS

Categories : Obstetrics & Gynaecology Surgeries & ProceduresTags :

Removing Fallopian Tubes during Other Abdominal Surgeries may Lower Ovarian Cancer Risk

On By ModernMedia

Mathematical modelling study suggests this approach could also reduce total healthcare costs in Germany

Female reproductive system. Credit: Scientific Animations CC4.0 BY-SA

A mathematical modelling study conducted in Germany suggests that ovarian cancer incidence could be reduced and healthcare savings boosted if women who have already completed their families were offered fallopian tube removal during any other suitable abdominal surgeries. Angela Kather and Ingo Runnebaum of Jena University Hospital, Germany, and colleagues present these findings on January 30th in the open-access journal PLOS Medicine.

Some of the most widespread and serious forms of ovarian cancer begin in the fallopian tubes, and removing them may reduce ovarian cancer risk. While women at average risk of ovarian cancer are not recommended to have surgery solely to remove their fallopian tubes, many surgeons offer “opportunistic” tube removal during other gynaecologic surgeries such as hysterectomy or tubal sterilisation. Opportunistic removal may also be feasible during other abdominal surgeries, such as gallbladder removal.

However, the overall potential benefits of opportunistic fallopian tube removal have been unclear. To help clarify, Kather and colleagues developed a mathematical model that incorporates real-world patient statistics to predict population-level risks of ovarian cancer after opportunistic fallopian tube removal, as well as the potential healthcare cost savings.

By applying the model to statistics from Germany, the researchers predicted that opportunistic fallopian tube removal during every hysterectomy and tubal sterilisation could reduce ovarian cancer cases by 5% across the female population of Germany. Removal during every suitable abdominal surgery for women who are done having children could reduce nationwide cancer cases by 15%, the analysis suggests, and it could save more than €10 million in healthcare costs annually.

Ovarian cancer is the third most common gynaecologic cancer in the world and has a mortality rate of 66%. Overall, these findings suggest that opportunistic fallopian tube removal during appropriate abdominal surgeries could not only lower population-level ovarian cancer risks and prevent ovarian cancer deaths, but also provide economic benefits. This study could help inform health policy and insurance costs for the procedure.

The authors add, “We developed a mathematical model to estimate the likelihood of women undergoing surgeries that offer an opportunity for fallopian tube removal and the potential for reducing their ovarian cancer risk. Applying this model to the entire female population of Germany revealed that 15% of ovarian cancer cases could be prevented if fallopian tubes were removed during every suitable abdominal surgery in women who have completed their families. This approach has the potential to extend healthy years of life and significantly save healthcare costs.”

Provided by PLOS

Categories : COVIDTags :

Study Tracks Physical and Cognitive Impairments Associated with Long COVID

On By ModernMedia

Researchers following nearly 1000 people with post-COVID-19 syndrome found few changes to their symptoms in the second year of illness

Photo by Usman Yousaf on Unsplash

Two-thirds of people with post-COVID-19 syndrome have persistent, objective symptoms – including reduced physical exercise capacity and reduced cognitive test performances – for a year or more, with no major changes in symptom clusters during the second year of their illness, according to a new study published January 23rd in the open-access journal PLOS Medicine by Winfried Kern of Freiburg University, Germany, and colleagues.

Self-reported health problems following SARS-CoV-2 infection have commonly been described and may persist for months. However, the long-term prognosis of post-COVID-19 syndrome (PCS) is unknown.

In the new study, researchers studied 982 people aged 18 to 65 who had previously been identified as having PCS, as well as 576 controls. All participants visited one of several university health centers in southwestern Germany for comprehensive assessments, including neurocognitive, cardiopulmonary exercise, and laboratory testing.

The predominant symptom clusters among people with PCS were fatigue/exhaustion, neurocognitive disturbances, chest symptoms/breathlessness, and anxiety/depression/sleep problems. Nearly 68% of people who originally reported PCS still struggled with symptoms in the second year. Exercise intolerance with post-exertional malaise was reported by 35.6% of people with persistent PCS, and these people had worse outcomes and more severe symptoms. People with lower educational attainment, obesity, or more severe illness during the initial COVID-19 infection were also at higher risk of prolonged symptoms.

When they looked at objective measures of health and cognition, the team found that people with persistent PCS had significant reductions in handgrip strength, maximal oxygen consumption, and ventilatory efficiency. Patients with persistent PCS and post-exertional malaise scored lower than control patients on cognitive tests measuring memory, attention, and processing speed; however, the researchers point out that they had no data on cognition before acute COVID-19 infection. The team was not able to identify differences in cardiac function or laboratory values, including tests of viral persistence.

“The results call for the inclusion of cognitive and exercise testing in the clinical evaluation and monitoring of patients with suspected PCS,” the authors say. “Observational studies with longer follow-up are urgently needed to evaluate factors for improvement and non-recovery from PCS.”

The authors add, “Grave symptoms with mental and physical exercise dysfunction, but no laboratory markers in Long Covid/post-Covid syndrome.”

Provided by PLOS

Categories : Diet and Nutrition Metabolic DisordersTags :

In Obesity or Not, Individuals Prefer High-calorie Food

On By ModernMedia

Calorie content drives food preference despite similar taste in individuals with and without obesity

Source: Pixabay CC0

Higher calorie foods were preferred among individuals with and without obesity despite similar taste and texture, according to a study published December 17th in the open-access journal PLOS Biology by Albino Oliveira-Maia from the Champalimaud Foundation, Portugal, and colleagues.

Eating sends signals to the brain with information about a food’s energy content, which can influence food preferences irrespective of flavor. People with obesity often have impairments in areas of the brain where dopamine is released, which may drive reward-related eating and a preference for energy-dense foods rich in fat and sugars. Weight loss due to bariatric surgery has been associated to a normalization of reward-related eating with a shift of preferences toward healthier options, but the underlying mechanisms are not well understood.

In this study, after examining a large group of healthy volunteers, researchers compared food preferences in three groups: 11 individuals with obesity, 23 post-bariatric surgery patients, and 27 non-obese control subjects. They gave participants sweetened low-fat yogurt with and without maltodextrin (a carbohydrate that adds calories to the yogurt with no impact on taste or texture). Participants ate the yogurt at home, alternating between the maltodextrin-containing and -free yogurt. All three groups ate more of the maltodextrin-containing yogurt, despite rating both as equally pleasant. Somewhat unexpectedly, the effects of maltodextrin on yogurt consumption were similar in individuals with obesity relative to their non-obese counterparts.

The study also used radioactive iodine labelling and single photon emission computed tomography to visualise dopamine receptors in the brain. Consistent with previous studies, individuals with obesity had lower dopamine receptor availability than non-obese controls. Dopamine receptor availability was similar in the surgical and non-obese groups and was associated with more restrained eating. These results suggest that obesity-related brain changes can be reversed after bariatric surgery, potentially impacting the amount of food consumed but not necessarily the types of food preferred.

The authors add, “We were very intrigued that, while behaviour was guided towards eating yoghurts with higher energy-content, this did not seem to be a result of explicit choices, since consistent changes in pleasantness of flavours enriched with carbohydrates were not found. Importantly, this behaviour was maintained in patients with obesity and after weight-loss surgery, even though there were important differences in their brain dopaminergic system.”

Provided by PLOS

Categories : New Compounds and Treatments OphthalmologyTags :

New Potential Treatment for Inherited Blinding Disease Retinitis Pigmentosa

On By ModernMedia

Researchers used a computer screening approach to identify two compounds that could help prevent vision loss in people with a genetic eye disease

Photoreceptor cells in the retina. Credit: Scientific Animations

Two new compounds may be able to treat retinitis pigmentosa, a group of inherited eye diseases that cause blindness. The compounds, described in a study published January 14th in the open-access journal PLOS Biology by Beata Jastrzebska from Case Western Reserve University, US, and colleagues, were identified using a virtual screening approach.

In retinitis pigmentosa, the retina protein rhodopsin is often misfolded due to genetic mutations, causing retinal cells to die off and leading to progressive blindness. Small molecules to correct rhodopsin folding are urgently needed to treat the estimated 100 000 people in the United States with the disease. Current experimental treatments include retinoid compounds, such as synthetic vitamin A derivatives, which are sensitive to light and can be toxic, leading to several drawbacks.

In the new study, researchers utilised virtual screening to search for new drug-like molecules that bind to and stabilise the structure of rhodopsin to improve its folding and movement through the cell. Two non-retinoid compounds were identified which met these criteria and had the ability to cross the blood-brain and blood-retina barriers. The team tested the compounds in the lab and showed that they improved cell surface expression of rhodopsin in 36 of 123 genetic subtypes of retinitis pigmentosa, including the most common one. Additionally, they protected against retinal degeneration in mice with retinitis pigmentosa.

“Importantly, treatment with either compound improved the overall retina health and function in these mice by prolonging the survival of their photoreceptors,” the authors say. However, they note that additional studies of the compounds or related compounds are needed before testing the treatments in humans.

The authors add, “Inherited mutations in the rhodopsin gene cause retinitis pigmentosa (RP), a progressive and currently untreatable blinding disease. This study identifies small molecule pharmacochaperones that suppress the pathogenic effects of various rhodopsin mutants in vitro and slow photoreceptor cell death in a mouse model of RP, offering a potential new therapeutic approach to prevent vision loss.”

Provided by PLOS

Categories : Mental Health NeurologyTags :

What Happens in the Brain When a Person with Schizophrenia ‘Hears Voices’?

On By ModernMedia
Source: Pixabay

Auditory hallucinations are likely the result of abnormalities in two brain processes: a “broken” corollary discharge that fails to suppress self-generated sounds, and a “noisy” efference copy that makes the brain hear these sounds more intensely than it should. That is the conclusion of a new study published October 3rd in the open-access journal PLOS Biology by Xing Tian, of New York University Shanghai, China, and colleagues.

Patients with certain mental disorders, including schizophrenia, often hear voices in the absence of sound.

Patients may fail to distinguish between their own thoughts and external voices, resulting in a reduced ability to recognise thoughts as self-generated.

In the new study, researchers carried out electroencephalogram (EEG) experiments measuring the brain waves of twenty patients diagnosed with schizophrenia with auditory hallucinations and twenty patients diagnosed with schizophrenia who had never experienced such hallucinations.

In general, when people are preparing to speak, their brains send a signal known as “corollary discharge” that suppresses the sound of their own voice.

However, the new study showed that when patients with auditory hallucinations were preparing to speak a syllable, their brains not only failed to suppress these internal sounds, but had an enhanced “efference copy” response to internal sounds other than the planned syllable.

The authors conclude that impairments in these two processes likely contribute to auditory hallucinations and that targeting them in the future could lead to new treatments for such hallucinations.

The authors add, “People who suffer from auditory hallucinations can ‘hear’ sounds without external stimuli. A new study suggests that impaired functional connections between motor and auditory systems in the brain mediate the loss of ability to distinguish fancy from reality.”

Provided by PLOS