Hypothyroidism occurs when the thyroid gland doesn’t make enough thyroid hormones. This can slow metabolism. Symptoms include feeling tired, weight gain and sensitivity to cold.

“In some cases, thyroid disorders have been associated with dementia symptoms that can be reversible with treatment,” said study author Chien-Hsiang Weng, MD, MPH, of Brown University in Providence, Rhode Island. “While more studies are needed to confirm these findings, people should be aware of thyroid problems as a possible risk factor for dementia and therapies that could prevent or slow irreversible cognitive decline.”

For the study, researchers looked at the health records of 7,843 people newly diagnosed with dementia in Taiwan and compared them to the same number of people who did not have dementia. Their average age was 75. Researchers looked to see who had a history of either hypothyroidism or hyperthyroidism. Hyperthyroidism, which is also called overactive thyroid, is when the thyroid produces too much hormone. This can increase metabolism. Symptoms include unintended weight loss, rapid or irregular heartbeat and nervousness or anxiety.

A total of 102 people had hypothyroidism and 133 had hyperthyroidism.

The researchers found no link between hyperthyroidism and dementia.

Of the people with dementia, 68 people, or 0.9%, had hypothyroidism, compared to 34 of the people without dementia, or 0.4%. When researchers adjusted for other factors that could affect the risk of dementia, such as sex, age, high blood pressure and diabetes, they found that people over age 65 with hypothyroidism were 80% more likely to develop dementia than people the same age who did not have thyroid problems. For people younger than 65, having a history of hypothyroidism was not associated with an increased risk of dementia.

When researchers looked only at people who took medication for hypothyroidism, they found they were three times more likely to develop dementia than those who did not take medication. “One explanation for this could be that these people are more likely to experience greater symptoms from hypothyroidism where treatment was needed,” Weng said.

Weng noted that the observational study does not prove that hypothyroidism is a cause of dementia; it only shows an association.

A limitation of the study was that researchers were not able to include information about how severe the hypothyroidism was for participants.

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Materials provided by American Academy of Neurology. Note: Content may be edited for style and length.

“We know a lot about pathways involved in image-forming vision, but until now it remained unknown if and how non-image-forming visual behaviors rely on these same pathways in the eye,” said Johan Pahlberg, Ph.D., head of the Photoreceptor Physiology Group at NEI and a senior author of the study.

Vision begins when light travels into the eye and hits the retina’s light-sensing photoreceptors. The photoreceptors transfer signals through several layers of retinal neuron before those signals are sent to the brain. Light also triggers certain non-vision functions, such as controlling how much light enters the eye through the pupil (pupillary light reflex) and regulating the wake/sleep cycle (circadian rhythm). Circadian rhythm disruption has been linked to sleep problems, obesity, and other health issues.

To investigate pathways used by image-forming versus non-image-forming functions in the retina, Pahlberg and colleagues studied groups of mice that had been genetically modified to turn off one or more pathway links, or synapses, between photoreceptors and their next downstream neuronal neighbors, called bipolar cells. The group investigated the roles of rod photoreceptors, which are sensitive to low light levels; cone photoreceptors, which see color; as well as three types of bipolar cells: rod bipolar cells, “on” cone bipolar cells, and “off” cone bipolar cells.

“On” cone bipolar cells react to increases in light, and “off” cone bipolar cells react to decreases in light. Cone photoreceptors can only communicate with cone bipolar cells, while rod photoreceptors have pathways to communicate with each of the bipolar cell types, depending on the level of light. Bipolar cells then communicate with other neurons in the retina, passing information to the optic nerve and on to the brain. Some mice in the study had no functional connections between rods and “on” bipolar cells, for example, or connections between cones and any bipolar cells, or lacked connections between rod and cone photoreceptors.

The researchers compared the mice’s responses to visual stimuli while assessing pupillary light responses and monitoring their nocturnal wake/sleep cycle. They determined that while image-forming vision can use rod and cone photoreceptors, as well as all the types of bipolar cells, the same was not true for non-image forming functions. The pupil response relies exclusively on rod photoreceptors, while cones are unable to control this behavior. Meanwhile, both circadian rhythm regulation and the pupil reflex only use “on” bipolar cells pathways, relying on rod bipolar cells and “on” cone bipolar cells, but not “off” cone bipolar cells.

“We were really surprised to find that animals with only ‘off’ bipolar cells can’t adjust to changes in the day/night cycle, but can still see and respond to visual events, meaning they have functional image-forming vision. It was really interesting to us that the non-imaging forming functions completely ignore information from the ‘off’ pathway,” said Pahlberg. “We were equally surprised that rod photoreceptors, which are optimized for low light conditions, were still being used for the pupillary response even when light levels were high. We really thought the rods would be maxed out at that point.”

Pahlberg expects many of these findings in mice will hold true for humans, since the retinal circuitry is similar across mammals. Moving forward, he intends to explore other non-image-forming functions of the retina, like mood regulation, and see how else these different retinal circuits are being used.

The research was funded by the intramural programs of NEI, NIMH, the National Institute of Dental and Craniofacial Research, and the National Institute of Neurological Diseases and Stroke.

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Materials provided by NIH/National Eye Institute. Note: Content may be edited for style and length.

In a study published in the journal PLOS ONE, University of Florida scientists found that gardening activities lowered stress, anxiety and depression in healthy women who attended twice-weekly gardening classes. None of study participants had gardened before.

“Past studies have shown that gardening can help improve the mental health of people who have existing medical conditions or challenges. Our study shows that healthy people can also experience a boost in mental wellbeing through gardening,” said Charles Guy, principal investigator on the study and a professor emeritus in the UF/IFAS environmental horticulture department.

The study was co-authored by an interdisciplinary team of researchers with the environmental horticulture department, the UF College of Medicine, the UF Center for Arts in Medicine and the UF Wilmot Botanical Gardens, which also hosted all the study treatment sessions.

Thirty-two women between the ages of 26 and 49 completed the study. All were in good health, which for this experiment meant screening for factors such as chronic health conditions, tobacco use and drug abuse, and having been prescribed medications for anxiety or depression. Half of the participants were assigned to gardening sessions, while the other half were assigned to art-making sessions. Both groups met twice a week for a total eight times. The art group served as a point of comparison with the gardening group.

“Both gardening and art activities involve learning, planning, creativity and physical movement, and they are both used therapeutically in medical settings. This makes them more comparable, scientifically speaking, than, for example, gardening and bowling or gardening and reading,” Guy explained.

In the gardening sessions, participants learned how to compare and sow seeds, transplant different kinds of plants, and harvest and taste edible plants. Those in the art making sessions learned techniques such as papermaking, printmaking, drawing and collage.

Participants completed a series of assessments measuring anxiety, depression, stress and mood. The researchers found that the gardening and art making groups experienced similar improvements in mental health over time, with gardeners reporting slightly less anxiety than art makers.

Given the relatively small number of participants and the length of the study, the researchers were still able to demonstrate evidence of what medical clinicians would call the dosage effects of gardening — that is, how much gardening someone has to do to see improvements in mental health.

“Larger-scale studies may reveal more about how gardening is correlated with changes in mental health,” Guy explained. “We believe this research shows promise for mental wellbeing, plants in healthcare and in public health. It would be great to see other researchers use our work as a basis for those kinds of studies.”

The idea of using gardening to promote better health and wellbeing — called therapeutic horticulture — has been around since the 19^th century.

But why does being around plants make us feel good? The answer might be found in the important role of plants in human evolution and the rise of civilization, the study’s authors explain. As a species, we may be innately attracted to plants because we depend on them for food, shelter and other means of our survival.

Whatever the deeper reasons might be, many of the study participants left the experiment with a newly discovered passion, the researchers noted.

“At the end of the experiment, many of the participants were saying not just how much they enjoyed the sessions but also how they planned to keep gardening,'” Guy said.

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Materials provided by University of Florida. Original written by Samantha Murray. Note: Content may be edited for style and length.

The building blocks of these microrobots are iron oxide nanoparticles that have both catalytic and magnetic activity. Using a magnetic field, researchers could direct their motion and configuration to form either bristle-like structures that sweep away dental plaque from the broad surfaces of teeth, or elongated strings that can slip between teeth like a length of floss. In both instances, a catalytic reaction drives the nanoparticles to produce antimicrobials that kill harmful oral bacteria on site.

Experiments using this system on mock and real human teeth showed that the robotic assemblies can conform to a variety of shapes to nearly eliminate the sticky biofilms that lead to cavities and gum disease. The Penn team shared their findings establishing a proof-of-concept for the robotic system in the journal ACS Nano.

“Routine oral care is cumbersome and can pose challenges for many people, especially those who have hard time cleaning their teeth” says Hyun (Michel) Koo, a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in Penn’s School of Dental Medicine and co-corresponding author on the study. “You have to brush your teeth, then floss your teeth, then rinse your mouth; it’s a manual, multi-step process. The big innovation here is that the robotics system can do all three in a single, hands-free, automated way.”

“Nanoparticles can be shaped and controlled with magnetic fields in surprising ways,” says Edward Steager, a senior research investigator in Penn’s School of Engineering and Applied Science and co-corresponding author. “We form bristles that can extend, sweep, and even transfer back and forth across a space, much like flossing. The way it works is similar to how a robotic arm might reach out and clean a surface. The system can be programmed to do the nanoparticle assembly and motion control automatically.”

Disrupting oral care technology

“The design of the toothbrush has remained relatively unchanged for millennia,” says Koo.

While adding electric motors elevated the basic ‘bristle-on-a-stick format’, the fundamental concept has remained the same. “It’s a technology that has not been disrupted in decades.”

Several years ago, Penn researchers within the Center for Innovation & Precision Dentistry (CiPD), of which Koo is a co-director, took steps toward a major disruption, using this microrobotics system.

Their innovation arose from a bit of serendipity. Research groups in both Penn Dental Medicine and Penn Engineering were interested in iron oxide nanoparticles but for very different reasons. Koo’s group was intrigued by the catalytic activity of the nanoparticles. They can activate hydrogen peroxide to release free radicals that can kill tooth-decay-causing bacteria and degrade dental plaque biofilms. Meanwhile Steager and engineering colleagues, including Dean Vijay Kumar and Professor Kathleen Stebe, co-director of CiPD, were exploring these nanoparticles as building blocks of magnetically controlled microrobots.

With support from Penn Health Tech and the National Institutes of Health’s National Institute of Dental and Craniofacial Research, the Penn collaborators married the two applications in the current work, constructing a platform to electromagnetically control the microrobots, enabling them to adopt different configurations and release antimicrobials on site to effectively treat and clean teeth.

“It doesn’t matter if you have straight teeth or misaligned teeth, it will adapt to different surfaces,” says Koo. “The system can adjust to all the nooks and crannies in the oral cavity.”

The researchers optimized the motions of the microrobots on a small slab of tooth-like material. Next, they tested the microrobots’ performance adjusting to the complex topography of the tooth surface, interdental surfaces, and the gumline, using 3D-printed tooth models based on scans of human teeth from the dental clinic. Finally, they trialed the microrobots on real human teeth that were mounted in such a way as to mimic the position of teeth in the oral cavity.

On these various surfaces, the researchers found that the microrobotics system could effectively eliminate biofilms, clearing them of all detectable pathogens. The iron oxide nanoparticles have been FDA approved for other uses, and tests of the bristle formations on an animal model showed that they did not harm the gum tissue.

Indeed, the system is fully programmable; the team’s roboticists and engineers used variations in the magnetic field to precisely tune the motions of the microrobots as well as control bristle stiffness and length. The researchers found that the tips of the bristles could be made firm enough to remove biofilms but soft enough to avoid damage to the gums.

The customizable nature of the system, the researchers say, could make it gentle enough for clinical use, but also personalized, able to adapt to the unique topographies of a patient’s oral cavity.

To advance this technology to the clinic, the Penn team is continuing to optimize the robots’ motions and considering different means of delivering the microrobots through mouth-fitting devices.

They’re eager to see their device help patients.

“We have this technology that’s as or more effective as brushing and flossing your teeth but doesn’t require manual dexterity,” says Koo. “We’d love to see this helping the geriatric population and people with disabilities. We believe it will disrupt current modalities and majorly advance oral health care.”

Hyun (Michel) Koo is a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in the School of Dental Medicine and co-director of the Center for Innovation & Precision Dentistry at the University of Pennsylvania.

Edward Steager is a senior research investigator in Penn’s School of Engineering and Applied Science.

Koo and Steager’s coauthors on the paper are Penn Dental Medicine’s Min Jun Oh, Alaa Babeer, Yuan Liu, and Zhi Ren and Penn Engineering’s Jingyu Wu, David A. Issadore, Kathleen J. Stebe, and Daeyeon Lee.

This work was supported in part by the National Institute for Dental and Craniofacial Research (grants DE025848 and DE029985), Procter & Gamble, and the Postdoctoral Research Program of Sungkyunkwan University.

In a paper published in Physical Review Letters, the researchers created a model that describes the spread and speed of tornado-like vortex tubes in superfluids. Vortex tubes are a key ingredient of turbulence, which is widely studied in classical physics. The motion of vortex tubes is relevant in a wide range of scenarios, such as the formation of hurricanes, the airborne transmission of viruses and the chemical mixing in star formation. But it is poorly understood in quantum fluids.

This work expands on a previous study that reported experimental results obtained in superfluid helium-4 within a narrow temperature range. Superfluids are liquids that can flow without resistance, and therefore without a loss of kinetic energy. When they are stirred, they form vortices that rotate indefinitely.

“By validating this model and showing that it describes the movement of vortices at a wide range of temperatures, we are confirming a universal rule for this phenomenon,” said Wei Guo, an associate professor of mechanical engineering at the FAMU-FSU College of Engineering. “This discovery may aid the development of advanced theoretical models of quantum fluid turbulence.”

In the previous study, Guo and his team traced the vortex tubes that appeared in superfluid helium-4, a quantum fluid that exists at extremely low temperatures. In that research, the team used tiny particles that were caught in the vortices to trace their movement. They found that the vortices spread out much faster than one would expect based on the tubes’ apparently random motion. This rapid spread is known as superdiffusion.

In the latest work, the researchers built a numerical model and used findings from their previous study to validate the model’s accuracy by reproducing experimental results. That allowed them to predict how vortex tubes might form and spread within superfluids at a wider temperature range. The simulation also produced unequivocal evidence supporting the physical mechanism that the authors proposed for explaining the observed vortex superdiffusion.

Researchers aim to understand turbulence in quantum fluids for the basic research benefits as well as for possible use in practical applications, such as the fabrication of nanowires. Vortex tubes attract particles that group together in incredibly thin lines. Controlling that process allows for manufacture of so-called nanowires, which have a thickness measured in nanometers.

“Particle dispersion in turbulent flow is a very active topic in the classical turbulence field, but it has received less attention in the quantum-fluid community,” said Yuan Tang, a co-lead author and a postdoctoral researcher at the FSU-headquartered National High Magnetic Field Laboratory. “Our work may stimulate more future research on particle dispersion in quantum fluids.”

Paper co-authors include Satoshi Yui and Makoto Tsubota from Osaka Metropolitan University, Japan, and Hiromichi Kobayashi from Keio University, Japan. This paper was selected by Physical Review Letters as an Editors’ Suggestion, a designation for papers that are particularly important, interesting and well written.

This research was supported by the National Science Foundation and the U.S. Department of Energy. Additional resources were provided by the National High Magnetic Field Laboratory at Florida State University, which is supported by the National Science Foundation and the State of Florida. This work was also supported by the Japan Society for the Promotion of Science.

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Materials provided by Florida State University. Original written by Bill Wellock. Note: Content may be edited for style and length.

“The lack of a universal pond definition causes a lot of confusion, from people wondering about the difference between a pond and a lake, to aquatic monitoring programs with different definitions across governmental agencies, even up to accurately modeling global carbon budgets,” said Meredith Holgerson, assistant professor of ecology and evolutionary biology and co-first author of “A functional definition to distinguish ponds from lakes and wetlands,” published June 21 in Scientific Reports.

“We wanted to evaluate how scientists and policymakers define ponds and examine whether ponds are functionally distinct from lakes and wetlands,” Holgerson said.

Their conclusion: Ponds are small and shallow waterbodies, with a maximum surface area of five hectares, a maximum depth of 5 meters and less than 30% emergent vegetation.

There are hundreds of millions or even billions of ponds globally — more than 95% of the world’s still waterbodies are small (under 10 hectares) — but the humble pond is understudied and has been largely left out of federal and state monitoring and protection programs. This is partly because their numbers make monitoring difficult but also because agencies fail to define them or distinguish them from lakes or wetlands. The neglect has implications for the accuracy of climate modeling, as ponds are high emitters of greenhouse gases, and their contribution to the global carbon budget is uncertain.

Holgerson and her team examined how scientists defined pond in more than 500 relevant scientific papers, coding it for different descriptors, like surface area or depth, and whether the descriptions were qualitative or quantitative.

“We found that there wasn’t one definition that researchers all cited, and the definitions were often qualitative, describing a pond as ‘small,’ for example,” Holgerson said.

The team also conducted a survey of state agencies in charge of waterbody monitoring and conservation. Half of the states had legislation that referenced ponds, but only one state (Michigan) defined ponds. Other states designated ponds as state waters or lumped them in with either lakes or wetlands.

The researchers found that ponds are not the same as lakes or wetlands, however. Further examination of the literature revealed that ponds have distinct ecological structures and function that make their categorization with either lakes or wetlands problematic.

Holgerson and her team plotted the relationships between surface area and various metrics of ecological structure or function. “We looked at parameters like gross primary production, respiration, chlorophyll levels, greenhouse gas emissions, diel temperature ranges, and the rate of gas exchange with the atmosphere,” Holgerson said. “Nine out of the 10 ecosystem parameters related nonlinearly to surface area, suggesting that ponds really are acting differently.”

They also examined how these ecosystem metrics related to depth and emergent vegetation — plants rooted in the bottom that extend to the surface — and again found nonlinear relationships. They used the thresholds for where waterbody functions began to change with surface area, depth, and emergent vegetation to arrive at their definition.

The distinct profile and characteristics of ponds means they shouldn’t be held to the same monitoring standards as lakes or wetlands, Holgerson said. “For example, ponds may have naturally higher nutrient concentrations and higher methane fluxes. We may need to develop unique water quality standards for pond monitoring.”

More research is needed to hone the definition, particularly to better understand waterbodies at the boundaries between wetlands and ponds, and ponds and lakes, and how size, depth, vegetation — and other variables like how sheltered a waterbody is — impact the pond’s functioning and its categorization.

“At the beginning of the study, we weren’t sure if our research would allow us to propose a new definition that we felt confident about, but we think the numbers we offer are solid and a great jumping off point for further research,” Holgerson said. “We do call for more research, especially to look at boundaries between wetlands, ponds, and lakes.”

Holgerson hopes the new definition will also call attention to ponds as distinct, significant ecosystems that are worthy of study, monitoring, and protection. “Researching and monitoring ponds can help us figure out how these globally abundant waterbodies function. There’s also an essential human element,” Holgerson said. “So many people have connections to ponds — they have childhood stories of catching frogs or learning to fish in a nearby pond.”

This research was supported by numerous agencies including the Global Lake Ecological Observatory Network, the National Science Foundation and the St. Olaf Collaborative Undergraduate Research and Inquiry Program.