Culture

The use of 'ice' flavoured e-cigarettes may be common and positively associated with conventional smoking and nicotine dependence among young adults, suggests research published online in the journal Tobacco Control.

And it's unclear where these' hybrid' vapes, combining fruit/sweet and cooling flavours, fit into current or future regulatory frameworks, which apply restrictions according to distinct flavour categories, point out the study authors.

'Ice' flavoured e-cigarettes--marketed as a combination of fruity/sweet and cooling flavours, such as 'blueberry ice' or 'melon ice'--recently entered the US market. Previous research suggests that young adult vapers prefer either fruit/sweet or menthol/mint flavours.

To try and gauge the appeal of these 'hybrid' vape flavours, and see if they might be linked to other behaviours around vaping and/or smoking among young adults, the study authors drew on 344 online survey responses submitted between May and August 2020.

The survey was part of the Happiness & Health Study--a prospective study of health behaviours which originally recruited 3396 ninth grade students in Los Angeles, California, in 2013.

The survey aimed to find out if respondents vaped and if so, which flavour they had used most often in the preceding 30 days: menthol/mint; fruit/sweet; or ice.

Respondents, whose average age was 21, were also asked if they smoked regular cigarettes, what symptoms of vaping dependency they had, and how often, and what type of vaping device they used.

Among the 407 ethnically diverse respondents who had vaped in the past 30 days, 383 provided information on flavours, but after excluding those who responded 'flavourless' or 'tobacco flavoured', the final analysis included 344 responses.

Overall, 168 (49%) reported most often using ice flavours; 60 (17%) menthol/mint; and 116 (34%) fruit/sweet.

Compared with the vapers of menthol/mint flavoured e-cigarettes, those vaping ice flavoured e-cigarettes were more likely to report smoking regular cigarettes over the previous 30 days: 31.5% vs 22%.

Ice flavour vapers were also less likely than menthol/mint vapers to report using rechargeable devices and more likely than fruit/sweet flavour users to use disposable non-cartridge devices: 65% vs 35%.

Disposable e-cigarettes are among the fastest growing segments of the e-cigarette market, note the study authors.

Ice flavour vapers were more likely to report symptoms of vaping dependence than fruit/sweet flavour vapers (67% vs 43%), to have started vaping during high school (74% vs 65%), and to report more daily vaping episodes: around 11 vs 8.

And they were also more likely than fruit/sweet or menthol/mint flavour vapers to report more vaping days over the past month: average 17 vs 12.

The study authors point out that their research relied on recall and didn't measure nicotine intake nor did it differentiate between e-cigarettes containing nicotine and those that didn't.

"While causality cannot be inferred from this cross sectional study," they caution, "it is possible that exposure to e-cigarettes in ice flavours may somehow increase nicotine vaping frequency and dependence," they add.

"Previous clinical laboratory studies show that fruit and menthol flavours each independently increase the appeal of e-cigarettes and suppress the aversive qualities of nicotine in young adults by creating perceptions of sweetness and coolness, respectively," they explain.

"Because ice flavours represent a hybrid that may contain both cooling and fruity flavouring constituents, it is unclear how these flavours fit into current and future regulatory policies that place differential restrictions across different flavour categories," they highlight.

"Further studies of the specific cooling agents and chemical constituents in ice flavoured products and the health effects of ice flavoured e-cigarette use are warranted," they conclude.

Reston, VA (Embargoed until 7:30 p.m. EDT, Monday, June 14, 2021)--A protein that is critical in cancer cell metabolism has been imaged for the first time with a newly developed radiopharmaceutical, 18F-DASA-23. Imaging with this novel agent has the potential to improve the assessment of treatment response for patients, specifically those with brain tumors. This study was presented at the Society of Nuclear Medicine and Molecular Imaging 2021 Annual Meeting.

Tumor cells go through various changes to survive and prosper in the body. One of the key changes they make is modifying a master switch, known as pyruvate kinase M2 (PKM2). PKM2 controls cell metabolism and allows the cell to make more of the building blocks necessary for cell division.

"Until now we've had no way to assess the presence or activity levels of the PKM2 protein involved in that switch," said Corinne Beinat, PhD, instructor of radiology in the Radiology/Molecular Imaging Program at Stanford University in Stanford, California. "Through the development of 18F-DASA-23, this is the first time we can noninvasively interrogate the biochemistry of a tumor with respect to this master switch PKM2."

The study focused on patients with glioblastoma brain tumors, as normal brain cells have very low levels of PKM2. Healthy volunteers and patients with glioblastoma underwent positron emission tomography/magnetic resonance imaging with 18F-DASA-23. The radiopharmaceutical was successful in visualizing PKM2 in glioblastoma patients, while it was rapidly cleared from the bodies of healthy volunteers.

"This radiopharmaceutical can be very beneficial in assessing whether brain tumor treatments are working," stated Beinat. "For example, if a brain tumor is treated with a drug and then imaged with 18F-DASA-23, we can potentially know very quickly whether the therapeutic approach is working. If it's not effective, we won't have to waste more time waiting to see if the tumor itself is shrinking."

She added that 18F-DASA-23 could also possibly be used in other cancers or to learn more about how normal tissues adjust their metabolism during development or in response to varied environmental conditions.

Abstract 99. "Initial Clinical Evaluation of [18F]DASA-23, a PET Imaging Tracer for Evaluation of Aberrantly Expressed Pyruvate Kinase M2 in Glioblastoma," Corinne Beinat, Chirag Patel, Tom Haywood, Lewis Naya, Jessa Castillo, Bin Shen, Tarik Massoud, Andrei Iagaru, Guido Davidzon, Lawrence Recht and Sanjiv Gambhir, Stanford University, Stanford, California.

Reston, VA (Embargoed until 7:30 p.m. EDT, Monday, June 14, 2021)--In patients with mild cognitive impairment, taking lipophilic statins more than doubles their risk of developing dementia compared to those who do not take statins. According to research presented at the Society of Nuclear Medicine and Molecular Imaging 2021 Annual Meeting, positron emission tomography (PET) scans of lipophilic statin users revealed a highly significant decline in metabolism in the area of the brain that is first impacted by Alzheimer's disease.

Statins are medications used to lower cholesterol and reduce the risk of heart attack or stroke. They are the most commonly used drugs in the developed world, and nearly 50 percent of Americans over age 75 use a statin. Different types of statins are available based on a patient's health needs, including hydrophilic statins that focus on the liver and lipophilic statins that are distributed to tissues throughout the body.

"There have been many conflicting studies on the effects of statin drugs on cognition," said Prasanna Padmanabham, project head, statins and cognition in the molecular and medical pharmacology student research program at the University of California, Los Angeles in Los Angeles, California. "While some claim that satins protect users against dementia, others assert that they accelerate the development of dementia. Our study aimed to clarify the relationship between statin use and subject's long-term cognitive trajectory."

Researchers separated study participants into groups based on three parameters: baseline cognitive status, baseline cholesterol levels and type of statin used. Participants underwent 18F-FDG PET imaging to identify any regions of declining cerebral metabolism within each statin group. Eight years of subject clinical data was analyzed.

Patients with mild cognitive impairment or normal cognition who used lipophilic statins were found to have more than double the risk of developing dementia compared to statin non-users. Over time, PET imaging of lipophilic statin users also showed a substantial decline in metabolism in the posterior cingulate cortex, the region of the brain known to decline the most significantly in the earliest stages of Alzheimer's disease. In contrast, no clinical or metabolic decline was found for users of other statins or for statin users with higher baseline serum cholesterol levels.

"By characterizing the metabolic effects associated with statin use, we are providing a new application of PET to further our understanding of the relationship between one of the most commonly used classes of drugs and one of the most common afflictions of the aging brain," noted Padmanabham. "Findings from these scans could be used to inform patients' decisions regarding which statin would be most optimal to use with respect to preservation of their cognition and ability to function independently."

Abstract 102. "Lipophilic Statins in Subjects with Early Mild Cognitive Impairment: Associations with Conversion to Dementia and Decline in Posterior Cingulate Brain Metabolism in a Long-term Prospective Longitudinal Multi-Center Study," Prasanna Padmanabham, Stephen Liu and Daniel Silverman, University of California, Los Angeles, Los Angeles, California.

When Erin Hecht was earning her Ph.D. in neuroscience more than a decade ago, she watched a nature special on the Russian farm-fox experiment, one of the best-known studies on animal domestication.

The study, running since 1958, tries to replicate the natural domestication of wolves to dogs by selectively breeding two strains of silver foxes so they exhibit certain behaviors. Scientists breed one to be tame and display dog-like behaviors with people, such as licking and tail wagging. The other is bred to react with defensive aggression when faced with human contact, while a third strain acts as the control and isn't bred for any specific behaviors.

Hecht, who's now an assistant professor in the Harvard Department of Human Evolutionary Biology, was fascinated by the experiment, which has helped scientists closely analyze the effects of domestication on genetics and behavior. But, she also thought something was missing.

"In that TV show, there was nothing about the brain," Hecht said. "I thought it was kind of crazy that there's this perfect opportunity to be studying how changes in brain anatomy are related to changes in the genome and changes in behavior, but nobody was really doing it yet."

Hecht acted fast and sent an email to Lyudmila N. Trut, the scientist running the Siberian institute where the Russian foxes were being studied. Fast forward to today and that email was foundational for a new study reporting on the surprising brain changes that occur in the Russian fox-farm experiment. Published Monday in the journal JNeurosci, the paper raises questions about some of the leading theories on domesticated animals' brains.

By analyzing MRI scans of the foxes, Hecht and her colleagues showed that both the foxes bred to be tame and those bred for aggression have larger brains and more grey matter than the brain of the control group (the foxes not bred for any particular behavior). These findings run in contrast to studies on chickens, sheep, cats, dogs, horses, and other animals that have shown domesticated species have smaller brains with less grey matter, than their wild forebears.

The team of researchers from Harvard, University of Illinois at Urbana-Champaign, Emory University, Cornell University, and the Russian Institute of Cytology and Genetics, explain the increase in size and grey matter, but can't yet be sure why this happens without further study. Their leading hypothesis centers on how the tame and aggressive strain have both been bred for specific behaviors at an accelerated time frame than many other domesticated animals. Dogs, for example, have been domesticated for at least 15,000 years.

"Both the tame and aggressive strains have been subject to intense, sustained selection on behavior, while the conventional strain undergoes no such intentional selection," they wrote. "Thus, it is possible that fast evolution of behavior, at least initially, may generally proceed via increases in grey matter."

As they analyzed the MRI scans, the research team noticed another surprise: similarities in the ways that the brains of the aggressive and tame foxes were changing. Both, for instance, showed enlargement in many of the same grey matter regions, including the prefrontal cortex, the amygdala, the hippocampus, and the cerebellum. This was despite the foxes being bred for opposite behaviors.

Results suggest that selection for opposite behavioral responses, in this case tame-versus-aggressive behavior, can produce similar changes in brain anatomy. The findings also suggest that significant changes to the structure and organization of the nervous system can evolve very quickly. In fact, it can happen within the span of less than a hundred generations.

Taken together, the researchers say the study's findings suggest existing ideas of brain changes in domestication may need revising, and that the brains of other animals, including humans, may have gone through similarly abrupt morphological shifts during times a sudden selection on behavior (rapid changes in environment or climate) occurred.

Next steps in the research include observing the foxes' brains scans at a cellular level.

The researchers believe there's a lot left to be learned from the Russian farm foxes and domesticated species, in general. That's because when a species splits from its wild counterpart, its brain, body, and behavior undergo rapid changes. Studying the foxes and other domesticated animals provides a window into these complex evolutionary processes.

"It's a more simple and straightforward way to see how evolution changes brains than we can achieve with just studying naturally occurring evolved brain changes," Hecht said.

Like amyloid plaque, the genetic variant APOE4 has long been associated with Alzheimer's disease, but still little is known about the role the gene plays in the disease process.

Now, a new study published in Nature Aging not only sheds light on how the gene may instigate a cascade of pathologies that contribute to Alzheimer's disease, but also suggests a new treatment target that might help people who carry the APOE4 gene in early and late stages of the disease. Keck School of Medicine of USC researchers found that APOE4 is associated with the activation of an inflammatory protein that causes a breakdown in the blood-brain barrier which protects the brain.

This research builds on a recent USC study that revealed APOE4 triggers leaks in the blood-brain barrier in humans, which lets toxic substances from the blood stream into the brain, damaging brain cells and disrupting cognitive functions. This process causes memory problems in patients whether or not their brain shows signs of amyloid-β, the sticky plaque peptide considered a hallmark of the disease.

The latest findings also suggest a new potential treatment to slow down or prevent the cognitive decline associated with Alzheimer's disease in patients with the APOE4 gene, independently of amyloid-β pathology.

"We're further focusing on therapeutics targets in blood vessels that could bring innovative treatments to people suffering from Alzheimer's disease, both early and late stages of the disease. Current findings in mouse models might be particularly promising for treating late stage disease in the presence of advanced amyloid-β pathology," said Berislav Zlokovic, MD, PhD, director of the Zilkha Neurogenetic Institute at the Keck School of Medicine of USC.

The role of APOE4, pericytes and Cyclophilin A in Alzheimer's disease

APOE4 has been shown to accelerate the blood-brain barrier breakdown by damaging pericytes, a layer of cells that strengthen and protect the brain capillaries which make up the blood-brain barrier. This breakdown is also associated with higher levels of Cyclophilin A, a pro-inflammatory protein, in the brain vessels of Alzheimer's disease patients with the APOE4 gene.

In this study, USC researchers focused on Cyclophilin A in mice with the APOE4 gene, which carries a high risk for Alzheimer's disease, and mice with the APOE3 gene, which carries an average risk for Alzheimer's disease. Cyclophilin A is found in pericytes and controls how strong the blood vessels are in maintaining the integrity of the blood-brain barrier. In the APOE4 mice, researchers found Cyclophilin A caused an enzyme that degrades blood vessels in the blood-brain barrier -- matrix metalloproteinase 9 (MMP9) -- to become active. This did not happen in the APOE3 gene mice.

Researchers then tried treating APOE4 mice with an inhibitor known to suppress Cyclophilin A. The inhibitor not only improved integrity in the blood-brain barrier in APOE4 mice, but also prevented development of further neuron loss and behavioral deficits. Researchers observed that the APOE4 mice treated with the inhibitor did not exhibit behavioral deficits during daily activities. This suggests that treatment targeting this pathway might have the potential to also slow down the progression of vascular and neurodegenerative disorders in people with Alzheimer's disease who have the APOE4 gene.

"So far there has been little hope for those in the late stage of the disease, which is very hard on patients and their loved ones," said Zlokovic. "We are excited to further study the potential that interventions focused on blood-brain barrier repair and blood vessel strength, independent of amyloid pathology, could have on slowing down or stopping neurodegeneration and cognitive decline in advanced Alzheimer's disease."

The inhibitor used in this study to suppress the Cyclophilin A, Debio-025, has been used in humans to treat hepatitis C, suggesting this could be a potential treatment for cognitive impairment in APOE4 carriers that show Cyclophilin A-MMP9 pathway activity in early or late disease stages.

Osaka, Japan - Researchers from the Graduate School of Engineering and the Center for Quantum Information and Quantum Biology at Osaka University unveiled a new solid state second-harmonic generation (SHG) device that converts infrared radiation into blue light. This work may lead to a practical daily-use deep ultraviolet light source for sterilization and disinfection.

Recently, deep ultraviolet (DUV) light sources have been attracting much attention in sterilization and disinfection. In order to realize a bactericidal effect while ensuring user safety, a wavelength range of 220-230 nm is desirable. But DUV light sources in this wavelength range that are both durable and highly efficient have not yet been developed. Although wavelength conversion devices are promising candidates, conventional ferroelectric wavelength conversion materials cannot be applied to DUV devices due to absorption edge.

Since nitride semiconductors such as gallium nitride and aluminum nitride have relatively high optical nonlinearity, they can be applied to wavelength conversion devices. Due to its transparency to 210 nm, aluminum nitride is particularly suitable for DUV wavelength conversion devices. However, realizing structures with periodically inverted polarity like conventional ferroelectric wavelength conversion devices has proven quite difficult.

The researchers proposed a novel monolithic microcavity wavelength conversion device without a polarity-inverted structure. A fundamental wave is enhanced significantly in the microcavity with two distributed Bragg reflectors (DBR), and counter-propagating second harmonic waves are efficiently emitted in phase from the one side. As the first step towards a practical DUV light source, a gallium nitride microcavity device was fabricated via microfabrication technology, including dry etching and anisotropic wet etching for vertical and smooth DBR sidewalls. By obtaining a blue SH wave, the effectiveness of the proposed concept was successfully demonstrated.

"Our device can be adapted to use a broader range of materials. They can be applied to deep ultraviolet light emission or even broadband photon pair generation," senior author Masahiro Uemukai says. The researchers hope that because this approach does not rely on materials or periodically inverted structures, it will make future nonlinear optical devices easier to construct.

Singapore, 14 June 2021 - Many butterfly species bear distinct circular markings known as eyespots on their wings, and the functions of these rings of contrasting colours vary. A long-standing theory is that they serve as anti-predator defences - small eyespots along the wing margin can protect butterflies by directing predators to attack less important parts of the body, such as the hindwings, enabling them to escape.

Most nymphalid family butterflies have half as many eyespots on their forewings compared to their hindwings. In particular, this has been observed in the bush brown butterfly Bicyclus anynana.

A recent research by biologists from the National University of Singapore (NUS) sought to understand the impact of uneven distribution of eyespots. The team, led by Professor Antónia Monteiro from the NUS Department of Biological Sciences, found that the location of these eyespots is key to their protective function.

In their studies, the researchers found that variants of the bush brown butterfly which have more forewing eyespots suffered higher levels of predator attacks on these wings which are crucial for flight. This ultimately led to increased rates of successful predation, causing a decline in their population. The team also discovered that this variant laid fewer eggs due to its faster demise, and thereby had lower fitness, in evolutionary terms, than those with less forewing eyespots.

The findings were first published in the journal Proceedings of the Royal Society B on 26 May 2021.

Observing predator behaviour

In a set of predation experiments, the research team observed the behaviour of mantids in attacking two variants of bush brown butterflies with differing forewing eyespot numbers. Butterflies in the first group each had two forewing eyespots, while those in the other group had four. The results showed that the butterflies with two additional eyespots in the second group experienced more intense attacks to their forewings, in addition to the typical attacks on the hindwings.

"Butterflies can cope with damaged hindwings, but their forewings are critical for all stages of flight, from general flight to evasive manoevering. With more forewing damage, these butterflies are less likely to escape attacks and, even if they do, they would struggle to survive future attacks. From this experiment, it is clear the forewing with more eyespots becomes a more important target for predators," explained Dr Ian Chan, Research Fellow with the NUS Department of Biological Sciences, who was part of the research team.

To demonstrate the effects of the mantids' attacks on the butterflies, the researchers looked into three indicators of the butterflies' fitness: the amount of wing damage they suffered, the number of eggs laid, and lifespan. The team found that when compared to butterflies with fewer forewing eyespots, those with more eyespots received more damage to their forewings, laid fewer eggs, and had shorter lifespans.

Uncovering the mysteries of eyespot patterns

"Our findings demonstrate how the location of eyespots on butterfly wings both influences and is influenced by the behaviour of their predators, revealing more of the complexity behind how animals communicate to one another. Such a discovery raises further questions about why some species of butterflies have the opposite pattern, carrying more forewing than hindwing eyespots instead," said Professor Monteiro.

To deepen their understanding, the NUS researchers are looking to investigate whole predator-prey communities to uncover further drivers of eyespot number diversity in butterflies.

A team of scientists has shown that the healing of skin blisters is driven by hair follicle stem cells, which delay their own development in the process.

The healing process of the tissues in the human body is particularly well-studied in skin, especially as skin serves as a layer of protection from the environment. However, there remain some specific types of skin injuries where the healing process is not well understood.

A team of scientists from Japan and Italy, including Associate Professor Ken Natsuga from the Graduate School of Medicine at Hokkaido University, have used models of skin blisters to explore the effects of injury on developing skin tissue. Their discoveries were published in the journal EMBO Reports.

The scientists performed their tests on mice which had artificially generated epidermal detachment, or skin blisters. They investigated the healing process by monitoring gene expressions and cell proliferation, tracing cell lineages, and employing mathematical models.

The team found that a type of stem cells (SCs), hair follicle stem cells (HFSCs), play an outsize role in blister healing. The HFSCs are mainly responsible for the healing of subepidermal blisters, from the base of the wound. The wound-healing activity of HFSCs is accompanied by delayed growth of hair follicles in the regenerated skin tissue. When HFSCs are reduced, another group of SCs, the interfollicular epidermal stem cells (IFESCs), can also contribute to healing, but only from the blister margins. They also confirmed that blister healing was affected by the shapes of keratinocytes, the primary skin cells, although the mechanism by which the shapes affect healing is still unclear.

The findings have revealed the balance between wound healing and development in skin, indicating many possibilities for the treatment of skin blistering in humans. The models used in this study may themselves be used for the development of new therapies for blister healing. The role of sweat glands could not be investigated, as mice lack sweat glands, and the role of mesenchymal cells, which have previously been shown to be involved in healing of skin wounds, was not examined. Future work will focus on these aspects.

"Our findings of the healing processes pave the way for tailored therapeutic interventions for epidermolysis bullosa, pemphigoid diseases and other blistering diseases," says Ken Natsuga.

Nearly 12,000 people in Sweden received sickness benefit from the Swedish Social Insurance Agency for COVID-19 during the first wave of the pandemic. The median duration of sick leave in this group was 35 days, but for many it was considerably more long-drawn-out, according to a University of Gothenburg study.

A research group in rehabilitation medicine at the University of Gothenburg has studied sick-leave patterns. The study now presented in the scientific journal BMC Public Health.

The study included all recipients of sickness benefit from the Social Insurance Agency for COVID-19 diagnoses in Sweden during the first pandemic wave, from 1 March to 31 August 2020, and monitored them for 4 months from the start of the sick-leave period.

Sickness benefit from the Swedish Social Insurance Agency is normally paid from day 15 of a sick-leave period. People whose sick leave lasted two weeks or less, with sick pay from the employer, were not included in the study.

Data from the Social Insurance Agency, the National Board of Health and Welfare, and Statistics Sweden were used. Describing sick leaves is a way to investigate the impact of diseases on society and individuals, but few other studies have specifically looked at this repercussion of the pandemic.

The results show that 11,955 people received sickness benefit for COVID-19 during the first wave. For a sizable proportion, sick leave was lengthy. The median time was 35 days, and for 9% sick leave was still underway at the end of the follow-up period, i.e., after 4 months.

The proportion of participants who were on sick leave for more than 12 weeks, i.e., those who may have been affected by what is known as "long-term COVID-19," was 13.3%.

Inpatient hospital care for COVID-19 was the strongest predictor of prolonged sick leave. Another major factor was sick leave in the previous year, 2019. Age, too, appears to have a bearing on the duration of sick leave.

However, the study showed no socioeconomic factors that clearly and consistently predicted long-drawn-out sick leave.

The research group behind the study belongs to the Department of Clinical Neuroscience at the Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, and Sahlgrenska University Hospital. Hanna C Persson is the study's corresponding author.

"The results indicate that the category of people who had been on long-term sick leave due to COVID-19 is heterogeneous, and that the disease is complex. For us to understand the whole picture, more studies are needed in this subject, and with a longer follow-up period," Persson says.

High running capacity is associated with health and longevity. However, whether high genetic running capacity promotes more efficient metabolism with aging is not known. A new study conducted in collaboration between the universities of Shanghai Jiao Tong University (China) and Jyväskylä (Finland) investigated the effects of genetic running capacity and aging on tissue metabolism. The study reveals that adipose tissue may have a key role in healthy aging.

Running capacity, expressed as aerobic capacity, refers to an individual's capacity to utilize oxygen and is known to decrease with age, thereby affecting the whole body metabolism and health.

"We currently lack the information whether high genetic aerobic capacity promotes healthier metabolism in different tissues as we age," explains Academy of Finland postdoctoral researcher Sira Karvinen from the Faculty of Sport and Health Sciences, University of Jyväskylä, Finland.

To study the question, animal models of high-capacity runners (HCR) and low-capacity runners (LCR) were utilized. These rodent lines differ in their aerobic capacity genetically. Samples of serum, muscle and adipose tissue were harvested from young and aged animals to explore the tissue metabolites.

"According to our results, high genetic running capacity was associated with more efficient amino acid metabolism in skeletal muscle. Inefficient amino acid metabolism is linked to increased adiposity and risk of metabolic diseases," says Karvinen.

High genetic running capacity and aging interactively affected lipid metabolism in muscle and adipose tissue, possibly contributing to healthier metabolism with aging.

The results suggest that adipose tissue may have a more significant role in promoting healthy aging than previously thought. According to the current literature, around 50% of an individual's aerobic capacity is genetically inherited and the other 50% can be gained via physical activity.

"Regular exercise promotes health whether you have genetically high or low aerobic capacity. Hence, it is highly recommended to promote one's metabolism with exercise especially at older age, when aerobic capacity as well as other health parameters decline," says the principal investigator, Professor Heikki Kainulainen from the Faculty of Sport and Health Sciences, University of Jyväskylä, Finland.

Universal school lunch programs make students healthier, and increase their lifetime income by 3%, according to a unique study from Lund University in Sweden published in The Review of Economic Studies.

Health disparities arise early in life and play a major role in economic outcomes among adults. Yet there are few studies on the long-term effects of school-based nutrition policies aimed at counteracting them. Researchers from Lund University and Stockholm University can now show that universal school lunch programs have significant long-term benefits for students' education, general health and income.

"Today, we take school lunches for granted in Sweden. But the fact is, it was a very conscious investment when Sweden introduced free lunches in the 1940s. These cooked meals were meticulously planned in terms of nutrition. This begs the question: did it affect students' well-being in the long-term? We wanted to find out", says Petter Lundborg, professor of economics at Lund University.

Sweden, Finland and Estonia have been serving free school meals for a long time, unlike the neighboring countries Norway and Denmark, where pupils bring their own lunch. In other countries, such as the US and the UK, poorer students are offered school meals, while others pay.

In the new study, the researchers examine the Swedish school lunch program that was introduced gradually in different municipalities from the mid-1940s. The program offered nutritious school lunches to all Swedish primary school students, free of charge.. The researchers focused on the introduction of school lunches between 1959 and 1969. They discovered that the initiative had a positive impact on the height of the students, their health as young adults, the level of education they attained, and their lifetime income.

"Our study shows that universal efforts that provide children with nutritious meals can be seen as a long-term investment. In other words: ensuring that children eat well, also pays off later in life in terms of health, education and income", says Dan-Olof Rooth, professor of economics at the Institute for Social Research (SOFI) at Stockholm University.

The study shows, among other things, that both boys and girls who took part in the school meal program throughout their schooling grew taller than those who did not have access to the program. Pupils who received school meals during the entire nine years of compulsory school became almost 1 cm taller and went to university more often compared with pupils without access to the program. However, most importantly, the students had a three percent higher lifetime income.

"We also noted some interesting differences in the effects, where children from poor households benefited the most, even if children from all households benefit to a certain extent. Students from poor families had a six percent higher lifetime income, and students from other households had about a two percent higher lifetime income. The reform thus benefited all students, from both poor and rich families", says Petter Lundborg.

The results are related: the students ate nutritious food at school, they became taller and more educated, which to a large extent can explain why they had a better income through life. However, the researchers found no long-term effects on mortality, morbidity or sick leave.

The effects of school meal programs can also be caused by factors that have nothing to do with nutrition. Therefore, the researchers also collected data on school absenteeism from municipal archives in Sweden. The researchers' analysis shows that the introduction of the school lunch program did not lead to any changes in school attendance, which was high even before school meals were introduced.

"A reasonable interpretation of our results is that the students became more receptive to what they were being taught when they ate a nutritious lunch. This is in line with a previous study, which found that test results among eleven-year-olds increased during the first year after the introduction of nutritious school meals in connection with the Jamie Oliver campaign in the UK", says Dan-Olof Rooth.

Petter Lundborg and Dan-Olof Rooth - who conducted the study together with Dr. Jesper Alex-Petersen - believe that their results are relevant to many western countries today, even though the Swedish school lunch program was introduced during the 1950s and 1960s. Sweden was a rich country, where school children did not lack food, but where parents lacked knowledge about healthy eating habits. The reform made school food nutritious and the same for everyone.

"It is important for many countries even today, because school meals and their nutritional content is a recurring issue. Our results show significant long-term economic benefits of school meals. You get a lot of 'bang for your buck' - it is extremely well-invested money", concludes Petter Lundborg.

About the study:

The researchers used newly collected historical data on the gradual implementation of the program across municipalities in Sweden between the years 1959 and 1969. During this period, 265 municipalities introduced the program, with a roughly equal number of municipalities each year.

These historical data were linked to administrative records that cover the population of primary school pupils, i.e., about 1.5 million pupils born 1942-1965. Using a difference-in-differences design, they estimated the impact of the school lunch reform on a broad range of outcomes taken from income and education registers, the military enlistment register, the medical birth register, and hospitalization and mortality registers.

Announcing a new article publication for BIO Integration journal. In this article the authors Yuhao Chen, Yue Li, Meng Du, Jinsui Yu, Fei Gao, Zhen Yuan and Zhiyi Chen from The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China, University of South China, Hunan, China and University of Macau, China discuss ultrasound neuromodulation: integrating medicine and engineering for neurological disease treatment.

Neurological diseases associated with dysfunctions of neural circuits, including Alzheimer's disease (AD), depression and epilepsy, have become increasingly prevalent. To tackle these issues, artificial stimulation or regulation of specific neural circuits and nuclei are employed to alleviate or cure certain neurological diseases.

Ultrasound neuromodulation is an emerging interdisciplinary approach, which integrates medicine and engineering methodologies in the treatment. With the development of medicine and engineering, ultrasound neuromodulation has gradually been applied in the treatment of central nervous system diseases. In this review, the authors summarize the mechanism of ultrasound neuromodulation and the advances of focused ultrasound (FUS) in neuromodulation in recent years, with a special emphasis on its application in central nervous system disease treatment.

FUS shows great potential for the treatment of epilepsy, tremor, AD, depression, and brain trauma. The authors also suggest future directions of ultrasound neuromodulation in clinical settings, with a focus on fusion with genetic engineering or nanotechnology

Various platforms which offer food home delivery services through courier services, such as riders or other types of distributors, have proliferated very quickly in recent years, especially in big cities. Due to this boom in last-mile delivery or logistics, UOC experts have studied the operation of the main food home delivery platforms, such as Just Eat, Glovo and Deliveroo, which work in the city of Barcelona, to analyse the profitability of these business models and estimate the number of orders needed to achieve this profitability.

"It's very difficult for these business models to be profitable by themselves", said Eduard J. Álvarez Palau, a researcher from the SUMA research group of the UOC's Faculty of Economics and Business, the main author of this work together with Ángel A. Juan, principal investigator of the ICSO research group of the UOC's IN3.

During the course of the research, the authors analysed public data from the different companies to ascertain how the profit is generated on this type of platform. As well as studying the revenues, both those which come directly from the restaurants and those which come from the clients, they also assessed the fixed costs and the variable costs involved in each delivery.

Profitability of the service

After analysing the context and the situation, the experts estimate that at least 8,000 orders a day are needed for this type of platform to begin to be profitable from its operation. "This would be the most benevolent scenario. With the alternative scenario, in which we add all those costs related to the expansion of this type of company in other markets, we find that these 8,000 services have to be increased to 19,000 for the operating system to profitable, which is a little surprising", explained Álvarez.

Despite this situation, these companies do not base their income on just their activity. They are founded on two pillars: the investors and venture capital funds which allow them to remain in the business and participate in other business models. "Although their main business is food home delivery, it's difficult for them to be economically profitable and, therefore, they have to begin to choose other complementary business models, such as the delivery of other types of products or complementary services for restaurants, such as ghost kitchens", he stressed.

Thanks to these participations, this type of platform thus obtains a higher percentage of profit. "Their ultimate goal tends to be to attract as many users as possible in order to offer them additional services, although it's true that in the course of the research we didn't focus on the internal algorithms of each platform".

For years now, this group of experts has been studying the different dynamics of urban logistics, especially the so-called "last mile", the final delivery of the product to the client. This has been a booming market in recent years and has been driven to a large extent by the circumstances arising from the pandemic. "This growth demonstrates a transformation that's taking place and continuing to grow".

Indeed, unlike other types of companies such as Amazon, the delivery people from home delivery platforms tend to be distributors who use bicycles or motorbikes, known as 'riders', because the origin of the product is restaurants from the city and greater flexibility is needed. "The cost of riders is another factor that we analysed and we considered alternative scenarios to the current ones", Álvarez added.

Future scenarios

Moreover, based on the data obtained, the authors observe future lines for this type of company in which the application of this type of services to other sectors, not just food delivery, is envisaged.

For example, one of the scenarios that the experts consider is the direct recruitment of the riders by these companies. In this case, the delivery costs would increase by 30%. However, the trend in this sector tends to be toward the mass outsourcing of riders with temporary employment agencies, which will slightly reduce this extra cost and maintain flexibility.

Indeed, the experts depict a future in which these companies also pursue several business lines in order to obtain greater economic profitability than that achieved from food home delivery operations.

This UOC research contributes to sustainable development goals (SDG) 8, decent work and economic growth, and 11, sustainable cities and communities.

Near-field light is invisible light at the subwavelength scale. Harnessed for a variety of practical applications, such as wireless power transfer, near-field light has an increasingly significant role in the development of miniature on-chip photonic devices. Controlling the direction of near-field light propagation has been an ongoing challenge that is of fundamental interest in photonics physics and can significantly advance a variety of applications.

So far, propagation of near-field light in a single direction is achieved by specific interactions between the electric dipole and the magnetic dipole in a system, which has led to inevitable complexities in device design. Hyperbolic metamaterials (HMMs), an important class of artificial anisotropic material with hyperbolic isofrequency contours, have attracted attention due to their unique ability to control near-field light by enabling subwavelength confinement of electromagnetic waves. Large wave-vector modes in HMMs are of particular interest because those modes are easier to integrate and have a smaller loss of energy at transfer.

As reported in Advanced Photonics, researchers from Tongji University in China recently demonstrated an all-electric scheme able to flexibly control the propagation direction of near-field light. They reported anomalous unidirectional excitation of hyperbolic modes with large wave-vector at subwavelength scales. According to their research, selective near-field coupling in HMMs is enabled by discrete electric dipoles with different phases, which serve as a metasource composed of all-electric components and with a symmetry-associated inner freedom.

Their research not only addresses the need for an all-electric experimental design scheme for near-field photonics, but also contributes fundamentally valuable symmetry-based excitation principles. Using a Huygens metasource, the researchers were able to observe the unidirectional excitation of hyperbolic bulk modes in a planar HMM. They found that unidirectional excitation in free space is the same as in the vertical direction, but opposite to that in the horizontal direction. These different propagation characteristics in horizontal and vertical directions are unique to the hyperbolic modes. In addition, the researchers used spin metasources to study the directional propagation of light in a planar hyperbolic waveguide. They found that, for the clockwise-rotating spin metasource, only the guided mode propagating from right to left is excited. And for the counterclockwise-rotating source, only the guided mode propagating from left to right is excited.

Overall, the research advances the fields of optical science and information communication, as the results provide the necessary conditions for highly efficient and experimentally verified photonics routing. For emerging applications in integrated optical devices, as well as wireless power transfer, switching, and filtering, this work promises unprecedented flexible control of near-field light.

The human gut microbiome is a complex community of trillions of microbes that are constantly interacting with each other and our bodies. It supports our wellbeing, immune system and mental health - but how is it sustained?

Researchers in the UK and Germany, alongside other international collaborators, have investigated the evolution of bacteria in the human gut microbiome - asking how these microbes persist throughout their lifetimes - taking into account internal and external influencing factors.

The results of the study will help inform tailored probiotics, live bacteria found in particular foods or supplements, as well as dietary or medical interventions, to treat gut disease and maintain a healthy gut microbiome.

Keeping a stable, healthy gut microbial population is mutually beneficial to us and the bacteria. In exchange for nutrition and a comfortable habitat, the microbe community returns the favour by providing us with health benefits, which we are now starting to understand.

Lead author and Group Leader Dr Falk Hildebrand from the Quadram Institute and Earlham Institute, explains: "We know that certain microbes colonise us at birth, and some can live with us for decades. Yet, although studies have looked at individual microbe species, the mechanisms and scale of persistence in the microbiome as a whole haven't been explored."

To examine this, a team of scientists at the Earlham Institute and Quadram Institute on the Norwich Research Park, along with the European Molecular Biology Laboratory (EMBL) in Germany, used metagenomics to analyse the evolutionary strategies and persistence of different bacteria in the human gut microbiome.

Metagenomics is the study of all of the genes from many different organisms in a population. In terms of the human gut microbiome, this process not only provides detailed information about the bacteria strains present but also indicates the enhancing capabilities of those different strains, based on their genetics, to keep the gut in good working order.

From analysing stool samples, the team re-examined metagenomes from over 2,000 adult and infant samples, including several from the same families and found three major dispersal strategies underlying human gut bacterial persistence. The data came from previously published studies looking at microbiome changes over time, with each individual providing on average 2-3 samples several months apart.

Last author and Director EMBL Heidelberg (Scientific Activities) Prof Peer Bork, said: "By looking into time series from individuals and family members and overlaying this with geographic information, ranging from household via city to country, we identified groups of bacterial strains that show different dispersal strategies. This presented very different persistence patterns in the host, regional spreading and the geographical distributions of hundreds of bacterial species."

The data was built into a diverse dataset of 5,278 metagenomes, which were probed to analyse patterns of persistence in the different types of bacteria and how these were influenced by the common factors: age, family members, geographic region, and antibiotic usage.

"Our analysis shows that most strains of bacteria present in the microbiome are very persistent - with the chances of a strain persisting for at least a year being over 90%," said Dr Hildebrand.

"Some microbe species did show consistent differences being either highly persistent taxonomic groups, or being low-persistent, relying more on exchanges between family members. In babies, however, the average persistence of bacterial strains dropped to 80%. This isn't unexpected; we know that especially in newborn babies there is an ongoing exchange of gut microbes."

Prof Bork, added: "What the study shows is that the intrinsic persistence levels of bacteria seen in adults are also reflected in children, and gradually we start to acquire those persistent bacteria up to about ten-years-old at which point the microbiome reaches a steady state. "

"Antibiotics had different effects of different types of bacteria, with the overall effect depending on how resilient different bacteria are, their intrinsic persistence, and to what extent they were replaceable within the microbiome."

To delve deeper into what drives persistence, the researchers compared microbiome communities beyond an individual level, but also across families, countries and regions. This allowed them to group bacteria based on their persistence characteristics and, through genomic analysis, look for clues to the evolution of these groups' strategies in dispersing among new human hosts.

Tenacious persistence

The first group, termed 'tenacious' bacteria, were the most persistent and well adapted for survival in the human gut. For example, these bacteria were able to survive by switching to different nutrition sources as the host moved through infancy and into adulthood.

Tenacious bacteria, however, are the ones most likely to be lost from the microbiome following antibiotic use. If we have been carrying these bacteria in us since childhood, their loss may be permanent. This is a particular concern in relation to over- and misuse of antibiotics.

Another group was termed the 'heredipersistent' bacteria, which are strains that are 'inherited' and cluster within families. These have a lower persistence in childhood and a higher turnover rate, suggesting cycles of reinfection is key to their persistence in an individual.

Genomic analysis showed that these bacteria tend to have genes allowing them to spread by spores, which would help transmission from, say, a parent to child, but also across a family unit.

A third group, named 'spatiopersistent', appear to cluster to their own geographic areas, but not associated with families.

With much current interest in maintaining or manipulating the microbiome for health, the research team hopes their holistic exploration of the evolution of different persistence in gut microbes will lead to better, more well-informed clinical strategies.

For example, one-off interventions like Faecal Microbiota Transplantation (FMT) may be suitable to introduce or even replace tenacious bacteria but not bacteria that rely on reinfection. These might benefit more from probiotic-based therapies or dietary changes that, over time, alter the gut environment to favour their colonisation and persistence.
The new insights into the wide-ranging and potentially permanent damage antibiotics can do to the microbiome could also point to new strategies to mitigate these differing effects.

"Our study gave us a much better idea of which gut bacteria are closely associated with their host, and which are more prone to switch between hosts. This is important information to inform pro-prebiotics and most medical applications targeting the human gut microbiome," added Dr Hildebrand.