Space solar power project ends first in-space mission with successes and lessons

Reports and Proceedings

CALIFORNIA INSTITUTE OF TECHNOLOGY

 

IMAGE: 

THE DOLCE STRUCTURE COMPLETELY DEPLOYED, OVER THE CANADIAN ARCTIC, ON SEPTEMBER 29, 2023. DOLCE STRUCTURE'S TRAC LONGERONS AND BATTENS ARE CLEARLY VISIBLE ABOVE THE ARCTIC ICE. THE FIBERGLASS BATTEN CONNECTORS ARE SHINING UNDER THE SUN (RIGHT PART).

view more 

CREDIT: SPACE SOLAR POWER PROJECT/CALTECH

One year ago, Caltech’s Space Solar Power Demonstrator (SSPD-1) launched into space to demonstrate and test three technological innovations that are among those necessary to make space solar power a reality.

The spaceborne testbed demonstrated the ability to beam power wirelessly in space; it measured the efficiency, durability, and function of a variety of different types of solar cells in space; and gave a real-world trial of the design of a lightweight deployable structure to deliver and hold the aforementioned solar cells and power transmitters.

Now, with SSPD-1’s mission in space concluded, engineers on Earth are celebrating the testbed’s successes and learning important lessons that will help chart the future of space solar power.

"Solar power beamed from space at commercial rates, lighting the globe, is still a future prospect.  But this critical mission demonstrated that it should be an achievable future," says Caltech President Thomas F. Rosenbaum, the Sonja and William Davidow Presidential Chair and professor of physics. 

SSPD-1 represents a major milestone in a project that has been underway for more than a decade, garnering international attention as a tangible and high-profile step forward for a technology being pursued by multiple nations. It was launched on January 3, 2023, aboard a Momentus Vigoride spacecraft as part of the Caltech Space Solar Power Project (SSPP), led by professors Harry Atwater, Ali Hajimiri, and Sergio Pellegrino. It consists of three main experiments, each testing a different technology:

• DOLCE (Deployable on-Orbit ultraLight Composite Experiment): a structure measuring 1.8 meters by 1.8 meters that demonstrates the novel architecture, packaging scheme, and deployment mechanisms of the scalable modular spacecraft that will eventually make up a kilometer-scale constellation to serve as a power station.
• ALBA: a collection of 32 different types of photovoltaic (PV) cells to enable an assessment of the types of cells that can withstand punishing space environments.
• MAPLE (Microwave Array for Power-transfer Low-orbit Experiment): an array of flexible, lightweight microwave-power transmitters based on custom integrated circuits with precise timing control to focus power selectively on two different receivers to demonstrate wireless power transmission at distance in space.

"It’s not that we don’t have solar panels in space already. Solar panels are used to power the International Space Station, for example,” says Atwater, Otis Booth Leadership Chair of Division of Engineering and Applied Science; Howard Hughes Professor of Applied Physics and Materials Science; director of the Liquid Sunlight Alliance; and one of the principal investigators of SSPP. “But to launch and deploy large enough arrays to provide meaningful power to Earth, SSPP has to design and create solar power energy transfer systems that are ultra-lightweight, cheap, flexible, and deployable."

DOLCE: Deploying the Structure

Though all of the experiments aboard SSPD-1 were ultimately successful, not everything went according to plan. For the scientists and engineers leading this effort, however, that was exactly the point. The authentic test environment for SSPD-1 provided an opportunity to evaluate each of the components and the insights gleaned will have a profound impact on future space solar power array designs. 

For example, during the deployment of DOLCE—which was intended to be a three- to four-day process—one of the wires connecting the diagonal booms to the corners of the structure, which allowed it to unfurl, became snagged. This stalled the deployment and damaged the connection between one of the booms and the structure. 

With the clock ticking, the team used cameras on DOLCE as well as a full-scale working model of DOLCE in Pellegrino's lab to identify and try to solve the problem. They established that the damaged system would deploy better when warmed directly by the Sun and also by solar energy reflected off Earth. 

Once the diagonal booms had been deployed and the structure was fully uncoiled, a new complication arose: Part of the structure became jammed under the deployment mechanism, something that had never been seen in laboratory testing. Using images from the DOLCE cameras, the team was able to reproduce this kind of jamming in the lab and developed a strategy to fix it. Ultimately, Pellegrino and his team completed the deployment through a motion of DOLCE's actuators that vibrated the whole structure and worked the jam free. Lessons from the experience, Pellegrino says, will inform the next deployment mechanism.

"The space test has demonstrated the robustness of the basic concept, which has allowed us to achieve a successful deployment in spite of two anomalies," says Pellegrino, Joyce and Kent Kresa Professor of Aerospace and Civil Engineering and co-director of SSPP. "The troubleshooting process has given us many new insights and has sharply focused us on the connection between our modular structure and the diagonal booms. We have developed new ways to counter the effects of self-weight in ultralight deployable structures." 

ALBA: Harvesting Solar Energy

Meanwhile, the photovoltaic performance of three entirely new classes of ultralight research-grade solar cells, none of which had ever been tested in orbit before, were measured over the course of more than 240 days of operation by the ALBA team, led by Atwater. Some of the solar cells were custom-fabricated using facilities in the SSPP labs and the Kavli Nanoscience Institute (KNI) at Caltech, which gave the team a reliable and fast way to get small cutting-edge devices quickly ready for flight. In future work, the team plans to test large-area cells made using highly scalable inexpensive manufacturing methods that can dramatically reduce both the mass and the cost of these space solar cells.

Space solar cells presently available commercially are typically 100 times more expensive than the solar cells and modules widely deployed on Earth. This is because their manufacture employs an expensive step called epitaxial growth, in which crystalline films are grown in a specific orientation on a substrate. The SSPP solar cell team achieved low-cost nonepitaxial space cells by using cheap and scalable production processes like those used to make today's silicon solar cells. These processes employ high-performance compound semiconductor materials such as gallium arsenide that are typically used to make high-efficiency space cells today.

The team also tested perovskite cells, which have captured the attention of solar manufacturers because they are cheap and flexible, and luminescent solar concentrators with the potential to be deployed in large flexible polymer sheets.

Over ALBA's lifespan, the team collected enough data to be able to observe changes in the operation of individual cells in response to space weather events like solar flares and geomagnetic activity. They found, for example, tremendous variability in the performance of the perovskite cells, whereas the low-cost gallium arsenide cells consistently performed well overall.

"SSPP gave us a unique opportunity to take solar cells directly from the lab at Caltech into orbit, accelerating the in-space testing that would normally have taken years to be done. This kind of approach has dramatically shortened the innovation-cycle time for space solar technology," says Atwater.

MAPLE: Wireless Power Transfer in Space

Finally, as announced in June, MAPLE demonstrated its ability to transmit power wirelessly in space and to direct a beam to Earth—a first in the field. MAPLE experiments continued for eight months after the initial demonstrations, and in this subsequent work, the team pushed MAPLE to its limits to expose and understand its potential weaknesses so that lessons learned could be applied to future design. 

The team compared the performance of the array early in the mission with its performance at the end of the mission, when MAPLE was intentionally stressed. A drop in the total transmitted power was observed. Back in the lab on Earth, the group reproduced the power drop, attributing it to the degradation of a few individual transmitting elements in the array as well as some complex electrical–thermal interactions in the system. 

"These observations have already led to revisions in the design of various elements of MAPLE to maximize its performance over extended periods of time," says Hajimiri, Bren Professor of Electrical Engineering and Medical Engineering and co-director of SSPP. "Testing in space with SSPD-1 has given us more visibility into our blind spots and more confidence in our abilities." 

SSPP: Moving Forward

SSPP began after philanthropist Donald Bren, chairman of Irvine Company and a life member of the Caltech community, first learned about the potential for space-based solar energy manufacturing as a young man in an article in Popular Science magazine. Intrigued by the potential for space solar power, Bren approached Caltech's then-president Jean-Lou Chameau in 2011 to discuss the creation of a space-based solar power research project. In the years to follow, Bren and his wife, Brigitte Bren, a Caltech trustee, agreed to make a series of dona­tions (yielding a total commitment of over $100 million) through the Donald Bren Foundation to fund the project and to endow a number of Caltech professorships. 

"The hard work and dedication of the brilliant scien­tists at Caltech have advanced our dream of providing the world with abundant, reliable, and affordable power for the benefit of all humankind," Donald Bren says. 

In addition to the support received from the Brens, Northrop Grumman Corporation provided Caltech with $12.5 million between 2014 and 2017 through a spon­sored research agreement that aided technology development and advanced the project’s science.

With SSPD-1 winding down its mission, the testbed stopped communications with Earth on November 11. The Vigoride-5 vehicle that hosted SSPD-1 will remain in orbit to support continued testing and demonstration of the vehicle's Microwave Electrothermal Thruster engines that use distilled water as a propellant. It will ultimately deorbit and disintegrate in Earth's atmosphere.

Meanwhile, the SSPP team continues work in the lab, studying the feedback from SSPD-1 to identify the next set of fundamental research challenges for the project to tackle.  

Same-level workplace falls set to rise amid surge in older female workforce numbers

Falls from height associated with male sex, construction work, and severe injuries. Better prevention strategies needed to mitigate these risk factors, say researchers

Peer-Reviewed Publication

BMJ

Same-level falls in the workplace are set to rise amid rapid growth in the numbers of older female employees in the workforce, suggests Australian research published online first in the journal Occupational & Environmental Medicine.

Although workplace falls, overall, are more common among male employees, particularly falls from height, same-level falls are more common in older women, the findings indicate.

The prevalence and relative severity of workplace falls mean that better prevention strategies are needed to mitigate these sex-specific risk factors, conclude the researchers.

In 2016, an estimated 1.53 million deaths and 76.1 million years of lived disability were caused by workplace injuries, note the researchers. Falls accounted for more than a quarter of these figures.

The Australian workforce is ageing: 50–64 year olds made up 11% of employees in the mid-90s, rising to  21% in 2023. And ageing in general is associated with a heightened risk of falls, say the researchers.

In a bid to uncover the risk profiles of workplace falls, they analysed hospital admission records for the state of Victoria, Australia, between July 2017 and June 2022. Only patients older than 15 and admitted as a result of a work-related injury were included in the analysis. 

The researchers compared fall and other injuries; ‘falls from height’ and ‘same-level falls’ ; age and sex; presence of co-existing long term conditions; time and place of injury; work and injury types; body parts involved; injury severity; and length of hospital stay. 

Some 45,539 people were admitted to hospital for work-related injuries during the study period, of which 42,176 admissions were included in the final analysis 

The average annual rate of hospital admission for a work-related injury was 2.54 in every 1000 employees, but men outnumbered women: 3.91 vs 0.98/1000 employees. 

Around 1 in 5 of these admissions (8669; 21%) were associated with a fall, around half of which (52%) were falls from a height, while 37% were same-level/low falls.

Falls from ladder/scaffolds (21%), stairs/steps (9%), building/structure (8.5%) and different level falls (13.5%) made up those from height. Other specified and unspecified falls represented 1.5% and 10.5%, respectively. Over half of the fall injuries were fractures.

The average annual rate of hospital admission associated with a workplace fall was 0.52 in every 1000 employees: 0.68 for men and 0.34 for women. 

Most work-related falls occurred in 25–64 year olds, with men accounting for more than two thirds (69%) of all such falls. Women aged 45 and older, however, accounted for 1 in 5 (21%) of these falls and more than 5% of other workplace injuries. 

While the rates for height falls were higher in men than in women: 0.44 vs 0.08 per 1000 workers, especially among those aged 45 and older, same-level falls were higher in women: 0.21 vs 0.18, particularly after the age of 50. 

“It is possible that this higher rate of high falls among men is explained by the greater rates of men, particularly young men, relative to  women, working in sectors in which working at height is relatively common, for example, construction, telecommunications, and mechanical engineering,” suggest the researchers.

Same-level fall rates were relatively low in the youngest age groups, but rose sharply with increasing age, and were highest among the oldest female employees.

One in five (21%) of fallers had at least one co-existing health condition recorded during their hospital stay—30% of those with fall-related injuries and 19% of those with other work-related injuries. 

Co-existing health problems were more common among those who had experienced a same-level fall than among those who had fallen from height, particularly circulatory, respiratory, and musculoskeletal conditions.

Falls, especially those from height, were more common among those working in construction, while other work-related injuries were more common among those working in agriculture, forestry, fishing and manufacturing. 

Fall injuries were more likely to be serious, compared with other work-related injuries; this was particularly evident for falls from height. Prolonged length of stay was also more common for falls than for other types of injury. Nearly a third of hospital days due to work-related injuries were attributable to falls.

The findings relate to just one state in Australia so may not be more widely applicable, and the coding indicating where the fall occurred included a high proportion of ‘unspecified’ entries, acknowledge the researchers.

But they write: “Our findings add to a growing body of evidence suggesting that older working-aged women are at increased risk of same-level falls and fall-related injuries, particularly in the presence of comorbidity (whereas we observed a different risk profile for high falls, which were associated with males and which did not have a pronounced association with the number of comorbidities).”

They add: “For employers of middle-aged female workers, employers either need to consider a generalised approach to fall reduction among their entire workforce … or perhaps a targeted ‘screening’ approach in which workers are offered opportunities to share health information relevant to fall risk (including history of falls).”

And they conclude: “Fall injuries, particularly same-level falls, are likely to increase in workplaces with current demographic changes, and employers, regulators, and policy makers could usefully consider raising the profile of workplace falls and developing effective prevention strategies.”

---

JOURNAL

Occupational and Environmental Medicine

DOI

10.1136/oemed-2023-109079 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Epidemiology of work-related fall injuries resulting in hospitalisation: individual and work risk factors and severity

ARTICLE PUBLICATION DATE

16-Jan-2024

 

Silkmoths: Different olfactory worlds of females and males

Female moths primarily use their sense of smell to find the best host plants on which to lay their eggs, with the deterrent effect of caterpillar feces playing an important role

Peer-Reviewed Publication

MAX PLANCK INSTITUTE FOR CHEMICAL ECOLOGY

 

IMAGE: 

FEMALE SILKMOTH (BOMBYX MORI) ON THE LEAF OF A MULBERRY TREE, THE ONLY HOST PLANT FOR THE OFFSPRING OF THESE MOTHS. THE COMBED ANTENNAE, WHICH ACT AS THE INSECT'S "NOSE" TO DETECT ODORS, ARE CLEARLY VISIBLE. THE LATERAL BRANCHES OF THE ANTENNAE ARE COVERED WITH THOUSANDS OF HAIR-LIKE STRUCTURES CALLED SENSILLA, WHICH HOUSE THE SENSORY NEURONS FOR ODOR DETECTION.

view more 

CREDIT: MARKUS KNADEN, MAX PLANCK INSTITUTE FOR CHEMICAL ECOLOGY

The world smells different for female silkmoths than for males

In humans, the sense of smell is similarly developed in men and women, although women have slightly more olfactory neurons and therefore a slightly more sensitive nose. On the whole, however, they perceive the same odors. Male moths, on the other hand, live in a completely different olfactory world to their female counterparts. For example, the antennae of male silkmoths - their "nose" - are highly specialized to detect female sex pheromones, while females cannot even smell their own pheromones. There are thousands of sensilla on the antennae, hair-like structures, which can be divided into morphologically and functionally distinct groups. The most common sensilla in males are long and contain two sensory neurons. One is specialized to detect bombykol, the sex pheromone of females, while the other responds to bombykal, a component of the pheromone of other moth species. While bombykol is highly attractive to male silkmoths, bombykal is a deterrent.

"Because female silkmoths cannot smell their own pheromone, it was long thought that their long sensilla also have a very specific function that is only found in females. After mating, the female's only task is to find a suitable plant on which to lay her eggs. It has therefore been suggested that the long sensilla of females are specialized to detect the attractive odor of mulberry trees. We wanted to test this assumption", says Sonja Bisch-Knaden, who leads a project group in the Department of Evolutionary Neuroethology at the Max Planck Institute for Chemical Ecology.

Long sensilla of female silkmoths recognize silkworm feces

Electrophysiological methods, such as measuring the activity of individual sensilla (single-sensillum recording), were crucial for the study’s results. The scientists not only tested many different individual odors, but also natural odor mixtures, such as those found in the leaves of the mulberry tree, caterpillar droppings, the body odor of moths or the meconium, a liquid that moths secrete when they hatch. All these odors, which play an ecological role in the silkmoth's environment, had been collected. The research team was also able to match the expression of olfactory receptors to the corresponding sensillum type. 

"We were surprised to find that neurons in the long sensilla of female silkmoths were not specialized to detect the odor of the host plant, as expected, but that one of the two neurons in the long sensilla is very sensitive to odors such as isovaleric acid and benzaldehyde. The detection of the odor of the mulberry leaf itself is carried out by neurons in medium-length sensilla", summarizes Sonja Bisch-Knaden.

Isovaleric acid and benzaldehyde are odor components of silkworm feces. Using a simple Y-maze test with an entrance arm that splits into two side arms through which either an odor or clean air (control) is introduced, the research team was able to elicit behavior in the otherwise immobile females that expressed attraction or aversion. Major differences became apparent when comparing virgin and mated females. The researchers showed that odors associated with caterpillar droppings did not trigger a specific reaction in virgin females, but had a deterrent effect on mated females. Presumably, the smell of feces helps females avoid mulberry trees, which are already full of silkworms when they lay their eggs.

In search of the male silkmoth pheromone

The pheromone of female silkmoths, bombykol, was chemically characterized as early as 1959 - the first insect pheromone ever. So far, scientists have not been able to identify a male counterpart. The current study provides clues, but no answers to the question of a male pheromone. "The second neuron in the females’ long sensilla is highly specific for (+)-linalool, an odor already identified as a component of the male pheromone in other butterfly species. However, no linalool could be found in the body odor of male silkmoths, and (+)-linalool alone had neither an attractive nor a repellent effect on female silkmoths in behavioral experiments", says Sonja Bisch-Knaden.

Special features of the odor perception of silkmoths

While investigating the molecular basis of odor detection in female silkmoths, the researchers noticed a peculiarity in the spatial organization of olfactory receptors. There are two families of olfactory receptors, the evolutionary older ionotropic receptors (IRs), which detect mainly acids, and the odorant receptors (ORs), which detect a wide range of chemically diverse compounds. Based on studies in the model fly Drosophila melanogaster, it was long thought that neurons expressing IRs or ORs usually occur in different types of sensilla, and that IRs never occur in long sensilla. In the silkmoth, however, an IR co-receptor for the detection of acids and the obligate OR co-receptor are both found in the same neurons located in long sensilla. This co-expression of IRs and ORs increases the chemical receptivity of the sensory neurons. Odors detected by both receptor types are processed and transmitted together, which could be advantageous for the unambiguous detection of ecologically important odor mixtures. "It is amazing that research on insect olfaction continues to produce surprising results. Our study shows that it is important to study more than just one model," says Bill Hansson, head of the Department of Evolutionary Neuroethology.

The researchers also found this co-expression of the two receptor types in the long sensilla of male silkmoths, which is why they assume that the detection of acids could also play an important ecological role in males. Further investigations will now clarify this.

---

JOURNAL

Proceedings of the Royal Society B Biological Sciences

DOI

10.1098/rspb.2023.2578 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Females smell differently: characteristics and significance of the most common olfactory sensilla of female silkmoths

ARTICLE PUBLICATION DATE

17-Jan-2024

ARACHNOLOGY

Spider venom heart drug a step closer

A spider venom molecule being investigated by a University of Queensland team has met critical benchmarks towards becoming a treatment for heart attack and stroke.

 NEWS RELEASE 16-JAN-2024

UNIVERSITY OF QUEENSLAND

 

IMAGE: 

RESEARCHERS SOURCED A MOLECULE FROM FUNNEL WEB SPIDER VENOM WHICH IS SHOWING PROMISE TO TREAT HEART ATTACKS.

view more 

CREDIT: INSTITUTE FOR MOLECULAR BIOSCIENCE, UNIVERSITY OF QUEENSLAND

A spider venom molecule being investigated by a University of Queensland team has met critical benchmarks towards becoming a treatment for heart attack and stroke.

Associate Professor Nathan Palpant and Professor Glenn King from UQ’s Institute for Molecular Bioscience have previously shown that the drug candidate Hi1a protects cells from the damage caused by heart attack and stroke.

Dr Palpant said a subsequent study has put the drug through a series of preclinical tests designed to mimic real-life treatment scenarios.

“These tests are a major step towards helping us understand how Hi1a would work as a therapeutic – at what stage of a heart attack it could be used and what the doses should be,” Dr Palpant said.

“We established that Hi1a is as effective at protecting the heart as the only cardioprotective drug to reach Phase 3 clinical trials, a drug that was ultimately shelved due to side effects.

“Importantly, we found that Hi1a only interacts with cells in the injured zone of the heart during an attack and doesn’t bind to healthy regions of the heart – reducing the chance of side effects.”

Professor King, who recently won the Prime Minister’s Prize for Innovation for developing the world’s first insecticides from spider venom, discovered Hi1a in the venom of the K’gari funnel web spider.

“Hi1a could reduce damage to the heart and brain during heart attacks and strokes by preventing cell death caused by lack of oxygen,” Professor King said.

“Our testing and safety studies from independent contract research organisations has provided evidence that Hi1a could be an effective and safe therapeutic.”

Infensa Bioscience, a company co-founded by the researchers, raised $23 million in 2022 to develop Hi1a for commercial purposes.

Infensa CEO and UQ researcher, Associate Professor Mark Smythe, said cardiovascular disease is the leading cause of death globally.    

“Most deaths from cardiovascular disease are caused by heart attacks and strokes, yet there are no drugs on the market that prevent the damage they cause,” Dr Smythe said.  

“An effective drug to treat heart attacks would have worldwide impact, providing a breakthrough to improve the lives of millions of individuals living with heart disease.”

The research team included Dr Meredith Redd from IMB as well as Dr Melissa Reichelt and Dr Yusuke Yoshikawa from UQ’s School of Biomedical Sciences.

The study was published in the world’s leading cardiac journal The European Heart Journal.

 

Video: https://youtu.be/73zFDfeuTv8

 

 

 

---

JOURNAL

European Heart Journal

DOI

10.1093/eurheartj/ehad793 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Acid-sensing ion channel 1a blockade reduces myocardial injury in rodent models of myocardial infarction

 

A manned submersible found a fault scarp of the 2011 Tohoku-oki megaquake in the Japan Trench

Peer-Reviewed Publication

NIIGATA UNIVERSITY

 

IMAGE: 

THIS VERTICAL CLIFF CONSISTS OF SOFT MUD DEPOSITED ON THE JAPAN TRENCH BOTTOM AND WAS UPLIFTED ~60 M BY THE 2011 MEGAQUAKE. THIS WAS THE FIRST TIME THAT THE FAULT SCARP OF A TRENCH-TYPE EARTHQUAKE WAS OBSERVED AND VISUALLY RECORDED.

view more 

CREDIT: NIIGATA UNIVERSITY

Niigata, Japan – On September 4, 2022, a geologist Hayato Ueda in Niigata University boarded a submarine vehicle with a pilot Chris May and had a dive into the Japan Trench within the epicenter area of the 2011 Tohoku-oki megaquake, which caused the devastating tsunami disaster. On the 7,500 m deep trench bottom, they found a 26 m high nearly vertical cliff on the eastern slope of a 60 m high ridge. Previous bathymetric surveys from the sea surface have revealed that the ridge did not exist before, and appeared just after the megaquake accompanied with a fault on its eastern flank. He and his colleague scientists on deck thus concluded that the cliff was a surface expression of a coseismic movement of the fault. The cliff consisted of unconsolidated soft mud. The lower slope than the cliff was occupied by abundant debris of the same soft mud blocks, which obviously supplied from the cliff. The observed sharp fracture surfaces and highly angular edges, both on the cliff and debris blocks, imply very quick increase of stress that fractured the soft muds before they plastically flowed, and thus support a coseismic origin of the cliff.

The vehicle traversed the ridge across the fault precisely measuring the topography using acoustic transponder and pressure gauge. The height and uplifted volume of the ridge both suggest a coseismic slip of the fault as large as 80–120 m (the value depends on the assumed dip angle of the underlying fault) in the Japan Trench. This estimation is greater than the previously estimated fault slip (~65 m) beneath the slope on the west of the trench axis. They attributed the excess fault slip in the trench to local enhancement owing to the uneven top surface of the subducting Pacific plate, which modified the fault geometry and stability.

The 2011 megaquake resulted from rupture and slip of the plate boundary fault between the northeast Honshu Island of Japan (Okhotsk plate) and the subducting Pacific plate. After the earthquake, many geodetic and geophysical studies have proposed that this coseismic fault movement probably propagated to the trench. Because topographic change by near-surface fault movement is one of the major causes of tsunamis, it is important to precisely know what occurred in the deep-sea trench when the trench-type earthquake such as the 2011 event occurred. However, because of great depths, no submersible vehicles (neither manned nor remotely operated) had been able to access to the Japan Trench bottom. This study was the first time to observe, visually record, and precisely measure the topographic change (including fault cliff) in the trench by a single trench-type megaquake event. It verified that the fault slip surely propagated to the surface at the 2011 event, and deduced that the amount of the slip was at least locally as great as 100 m. These results are expected to contribute to our understanding of genesis and to hazards of tsunamis triggered by trench-type earthquakes. This study was published by the journal communications earth & environment on Dec. 26, 2023 https://doi.org/10.1038/s43247-023-01118-4

The submersible “DSV Limiting Factor” used for the survey. 

This vehicle has an ability to dive into the depth of 11,000 m, the world’s deepest ocean bottom, and thus is called as a “full-depth submersible”. It enabled researchers to approach to the Japan Trench bottom in the epicenter area for the first time more than 10 years after the megaquake. Without in situ observation using this submersible, the fault scarp in the ultra-deep sea would not have discovered.

CREDIT

Niigata University

---

JOURNAL

Communications Earth & Environment

DOI

10.1038/s43247-023-01118-4 

ARTICLE TITLE

The submarine fault scarp of the 2011 Tohoku-oki Earthquake in the Japan Trench

 

Video gamers worldwide may be risking irreversible hearing loss and/or tinnitus

Studies suggest game sound levels often near, or exceed, permissible safe limits. Greater public health efforts needed to raise awareness of potential risks, urge researchers

Peer-Reviewed Publication

BMJ

Video gamers worldwide may be risking irreversible hearing loss and/or tinnitus—persistent ringing/buzzing in the ears—finds a systematic review of the available evidence, published in the open access journal BMJ Public Health.

 

What evidence there is suggests that the sound levels reported in studies of more than 50,000 people often near, or exceed, permissible safe limits, conclude the researchers. 

And given the popularity of these games, greater public health efforts are needed to raise awareness of the potential risks, they urge.

While headphones, earbuds, and music venues have been recognised as sources of potentially unsafe sound levels, relatively little attention has been paid to the effects of video games, including e-sports, on hearing loss, say the researchers.

Gamers often play at high-intensity sound levels and for several hours at a time, they add. And one estimate indicates that there were more than 3 billion gamers worldwide in 2022. 

To try and build an evidence base, the researchers trawled research databases looking for relevant studies and white papers, newsletters, reports, and proceedings, collectively referred to as ‘grey literature,’ published at any point in English, Spanish, or Chinese.

Some 14 peer reviewed studies from 9 countries in North America, Europe, South East Asia, Asia and Australasia, and involving a total of 53,833 people, were included in the review.

Eleven were cohort (epidemiological observational) studies, 6 of which looked at the associations between hearing and computer or video games; 4 focused on gaming centres or personal computer rooms, which are popular in Asia; and 1 focused on mobile devices.

Reported sound levels ranged from 43.2 decibels (dB) (mobile devices) up to 80-89 dB (gaming centres) while length of noise exposure varied by mode and frequency of access–from daily to once a month, for at least an hour at a time, averaging 3 hours/week.

Impulse sounds consist of bursts lasting less than 1 second, with peak levels at least 15 dB higher than the background sound. One study reported that impulse sounds reached levels as high as 119 dB during game play; permissible exposure limits are around 100 dB for children and 130–140 dB for adults.

The International Telecommunication Union (ITU), in collaboration with the World Health Organization, describes a time–intensity trade-off, known as an exchange rate, for permissible levels and duration of exposure, explain the researchers. 

For example, a permissible noise exposure level of 80 dB for 40 hours a week with a 3 dB exchange rate means the permissible exposure time halves with every 3 dB increase in noise level: at 83 dB it’s 20 hours; at 86 dB it’s 10 hours; at 92 dB it’s 2.5 hours; and at 98 dB it’s 38 minutes.

For children, the permissible noise exposure level is defined as 75 dB for 40 hours a week. Children can therefore safely listen to an 83 dB sound for around 6.5 hours, 86 dB for around 3.25 hours, 92 dB for 45 minutes, and 98 dB for only 12 minutes a week, explain the researchers.

Six studies reported on video gaming prevalence among young people, which ranged from 20% to 68%. Two South Korean studies reported a prevalence of gaming centre use at around 60%.

Five studies evaluated associations between gaming and self-reported hearing loss, hearing thresholds, or tinnitus. Of these, 2 found that  school pupils’ gaming centre use was linked to increased odds of severe tinnitus and high-frequency sound hearing loss in both ears.

Another large observational study reported that video gaming was associated with increased odds of self-reported hearing loss severity.

One study reported that over 10 million people in the USA may be exposed to ‘loud’ or ‘very loud’ sound levels from video or computer games. 

One study measured sound levels of 5 video games through headphones attached to the gaming console, and found that these averaged 88.5, 87.6, 85.6 and 91.2 dB for 4 separate shooter games, and 85.6 dB for a racing game.

The authors therefore concluded that the daily level of sound exposure from these video games is close to maximum permissible levels of sound exposure.

An additional 16 peer-reviewed articles and 14 grey literature sources mention gaming as a potential source of excessive sound exposure.

One grey literature source sought to discover gamers’ preferred listening levels while wearing headphones.  The author concluded that gaming headphones can reach unsafe listening levels, “which could place some gamers at risk of sound-induced hearing loss.”

Three studies evaluated gender differences in gaming behaviours. Altogether, these indicated that boys played video games more often than girls, for longer periods of time, and at higher sound intensity levels.

The researchers acknowledge that some of the included studies date back to the early 1990s, and only 2 published in the past 10 years objectively measured average sound levels from video games or at gaming centres, although both reported high sound levels in these circumstances.

“Although the data provided in this review are limited, they suggest that some gamers, particularly those who play frequently, and at or above the average sound levels described by papers included in this review, probably exceed permissible sound exposure limits, and are thus engaging in unsafe listening practices, which could put them at risk for developing permanent hearing loss and/or tinnitus,” they nevertheless conclude.

There are also several key gaps in the available evidence, they add. For example, the impact of esports, geographic region, sex, and age, on hearing loss. Further research is essential to inform preventive measures and global policy initiatives, they suggest.

“The findings suggest that there may be a need to prioritise interventions, such as initiatives focused on education and awareness of the potential risks of gaming, that can help promote safe listening among gamers,” they suggest.

 

---

JOURNAL

BMJ Public Health

DOI

10.1136/bmjph-2023-000253 

METHOD OF RESEARCH

Systematic review

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Risk of sound-induced hearing loss from exposure to video gaming or e-sports: a systematic scoping review

ARTICLE PUBLICATION DATE

16-Jan-2024

COI STATEMENT

None declared

Disclaimer: AAAS a

 

Supports help keep Aussie firefighters safe

Peer-Reviewed Publication

UNIVERSITY OF SOUTH AUSTRALIA

House fires, road crashes and emergency rescues – they’re all part of the job for Aussie firefighters. And in such physically demanding roles, maintaining a high level of fitness and movement quality is essential.

 

Now, new research from health and fitness experts at the University of South Australia shows that professional firefighters have reduced movement quality as they age, which could put them at greater risk of injury.

 

Conducted by UniSA masters researcher, Alex Redshaw, in partnership with the South Australian Metropolitan Fire Service (MFS), the findings indicate that firefighters over the age of 50 generally have lower movement quality than their younger counterparts, and would benefit from additional functional strength training to maintain a fit and healthy workforce.

 

Good movement quality underpins all essential movements required to safely perform critical components of physical function, including balance, stability, and muscular strength. It is developed through functional strength training using exercises that replicate body movements and patterns seen in daily activities (such as lunging, squatting, bracing, pressing).

 

This is the first study on the effect of age on movement quality in Australian firefighters, and largest firefighter cohort in the world.

 

Statistics shows that firefighters have an injury rate more than three times that of the non-tactical workforce. It is well-established that movement quality deteriorates with age in the general population, but there is conflicting evidence in older tactical populations.

 

With an ageing population and more than 40% of South Australian firefighters aged over 50, the MFS was keen to understand how they could best support their members to maintain a safe and healthy career for as long as possible.

 

Assessing movement quality, physical activity, injury history and body mass index (BMI) among 324 South Australian MFS firefighters, researchers found that firefighters older than 50 were more likely to have poor movement quality.

 

It also found that firefighters with a high BMI, who participate in less than 150 minutes of physical exercise per week, and have had a musculoskeletal injury in the past 12 months, have lower movement quality, and may be at an increased risk of injury.

 

UniSA researcher, Dr Hunter Bennett, says exercise interventions could be offered as part of a supportive workplace health and safety program.

 

“Firefighters are routinely exposed to unique physiological and physical hazards, including extreme temperatures, heavy personal protective gear and unstable workspaces, all of which contribute to an increased risk of injury,” Dr Bennett says.

 

“Good movement quality supports well-coordinated performance within these environments, but ageing can deteriorate these functions, which may put older firefighters at risk.

 

“The MFS deploys a range of supports to maintain a fit and healthy workforce but is always on the lookout for additional improvements to benefit their members.

 

“In this study we found that older firefighters had poorer movement quality than their younger counterparts, and that this increased with age. Additionally, firefighters who did more exercise (more than five hours a week) had better movement quality.

 

“Knowing this, the MFS can support their members by offering specific movement quality programs to better maintain their physical capabilities as they age.”

 

Notes to editors:

 

The University of South Australia would like to thank the South Australian Metropolitan Fire Service for supporting this UniSA postgraduate research project.

 

The research paper can be accessed here: Redshaw, Alex & Carrick-Ranson, Graeme & Bennett, Hunter & Norton, Kevin & Walker, Anthony. (2023). Effect of Aging on Movement Quality in Australian Urban Firefighters. Journal of Strength and Conditioning Research. 37. e601-e608. 10.1519/JSC.0000000000004528

 

…………………………………………………………………………………………………………………………..

 

Media contact: Annabel Mansfield M: +61 479 182 489 E: Annabel.Mansfield@unisa.edu.au

Researcher: Dr Hunter Bennett E: Hunter.Bennett@unisa.edu.au

---

JOURNAL

The Journal of Strength and Conditioning Research

DOI

10.1519/JSC.0000000000004528 

METHOD OF RESEARCH

Randomized controlled/clinical trial

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Effect of Aging on Movement Quality in Australian Urban Firefighters