Faster air exchange in buildings not always beneficial for coronavirus levels

Modeling study suggests vigorous ventilation can cause spike in viral concentrations

DOE/PACIFIC NORTHWEST NATIONAL LABORATORY

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IMAGE: WHEN THE INFECTED PERSON IN THE OFFICE TO THE LEFT COUGHS, RESPIRATORY DROPLETS CONTAINING VIRAL PARTICLES EXIT VIA THE OFFICE'S VENT IN THE CEILING. SOME DROPLETS EXIT THE BUILDING, WHILE... view more 

CREDIT: ILLUSTRATION/ANIMATION: CORTLAND JOHNSON/SARA LEVINE, PACIFIC NORTHWEST NATIONAL LABORATORY

Vigorous and rapid air exchanges might not always be a good thing when it comes to addressing levels of coronavirus particles in a multiroom building, according to a new modeling study.

The study suggests that, in a multiroom building, rapid air exchanges can spread the virus rapidly from the source room into other rooms at high concentrations. Particle levels spike in adjacent rooms within 30 minutes and can remain elevated for up to approximately 90 minutes.

The findings, published online in final form April 15 in the journal Building and Environment, come from a team of researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory. The team includes building and HVAC experts as well as experts in aerosol particles and viral materials.

"Most studies have looked at particle levels in just one room, and for a one-room building, increased ventilation is always useful to reducing their concentration," said Leonard Pease, lead author of the study. "But for a building with more than one room, air exchanges can pose a risk in the adjacent rooms by elevating virus concentrations more quickly than would otherwise occur.

"To understand what's happening, consider how secondhand smoke is distributed throughout a building. Near the source, air exchange reduces the smoke near the person but can distribute the smoke at lower levels into nearby rooms," Pease added. "The risk is not zero, for any respiratory disease."

The team modeled the spread of particles similar to SARS-CoV-2, the virus that causes COVID-19, via air-handling systems. Scientists modeled what happens after a person has a five-minute coughing bout in one room of a three-room small office building, running simulations with particles of five microns.

Researchers looked at the effects of three factors: different levels of filtration, different rates of outdoor air incorporation into the building air supply, and different rates of ventilation or air changes per hour. For downstream rooms, they found an expected clear benefit from increasing outdoor air and improving filtering, but the effect of increased ventilation rate was less obvious.

More clean outdoor air reduces transmission

Scientists studied the effects of adding varying amounts of outdoor air to the building air supply, from no outside air to 33 percent of the building's air supply per hour. As expected, the incorporation of more clean outdoor air reduced transmission risk in the connected rooms. Replacement of one-third of a building's air per hour with clean outdoor air in downstream rooms reduced infection risk by about 20 percent compared to the lower levels of outdoor air commonly included in buildings. The team noted that the model assumed that the outdoor air was clean and virus free.

"More outside air is clearly a good thing for transmission risk, as long as the air is free of virus," said Pease.

Strong filtration reduces transmission

The second factor studied--strong filtration--also was very effective at reducing transmission of the coronavirus.

The team studied the effects of three levels of filtration: MERV-8, MERV-11, and MERV-13, where MERV stands for minimum efficiency reporting value, a common measure of filtration. A higher number translates to a stronger filter.

Filtration decreased the odds of infection in the connected rooms markedly. A MERV-8 filter decreased the peak level of viral particles in connected rooms to just 20 percent what it was without filtration. A MERV-13 filter knocked down the peak concentration of viral particles in a connected room by 93 percent, to less than one-tenth of what it was with a MERV-8 filter. The researchers note that the stronger filters have become more common since the pandemic began.

Increasing ventilation--a more complex picture

The most surprising finding of the study involved ventilation--the effect of what researchers call air changes per hour. What's good for the source room--cutting transmission risk within the room by 75 percent--is not so good for connected rooms. The team found that a rapid rate of air exchange, 12 air changes per hour, can cause a spike in viral particle levels within minutes in connected rooms. This increases the risk of infection in those rooms for a few minutes to more than 10 times what it was at lower air-exchange rates. The higher transmission risk in connected rooms remains for about 20 minutes.

"For the source room, clearly more ventilation is a good thing. But that air goes somewhere," said Pease. "Maybe more ventilation is not always the solution."

Interpreting the data

"There are many factors to consider, and the risk calculation is different for each case," said Pease. "How many people are in the building and where are they located? How large is the building? How many rooms? There is not a great deal of data at this point on how viral particles move about in multiroom buildings.

"These numbers are very specific to this model--this particular type of model, the amount of viral particles being shed by a person. Every building is different, and more research needs to be done," Pease added.

Co-author Timothy Salsbury, a buildings control expert, notes that many of the trade-offs can be quantified and weighted depending on circumstances.

"Stronger filtration translates to higher energy costs, as does the introduction of more outside air than would usually be used in normal operations. Under many circumstances, the energy penalty for the increased fan power required for strong filtration is less than the energy penalty for heating or cooling additional outside air," said Salsbury.

"There are many factors to balance--filtration level, outdoor air levels, air exchange--to minimize transmission risk. Building managers certainly have their work cut out for them," he added.

Additional experimental studies underway

The team is already conducting a series of experimental studies along the same lines as the modeling study. Like the newly published study, the additional analyses look at the effects of filtration, outdoor air incorporation and air changes.

These ongoing studies involve real particles made of mucus (not incorporating the actual SARS-CoV-2 virus) and consider differences among particles expelled from various parts of the respiratory tract, such as the oral cavity, the larynx, and the lungs. Investigators deploy an aerosolizing machine that disperses the viral-like particles much as they'd be dispersed by a cough, as well as fluorescent tracking technology to monitor where they go. Other factors include varying particle sizes, how long viral particles are likely to be infectious, and what happens when they drop and decay.

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In addition to Pease and Salsbury, authors of the published study include Nora Wang, Ronald Underhill, Julia Flaherty, Alex Vlachokostas, Gourihar Kulkarni and Daniel James.

The research, the latest in a series of PNNL findings about COVID-19, brings together PNNL's strengths in building technologies and in aerosol science. The work was funded through the National Virtual Biotechnology Laboratory, a consortium of all 17 DOE national laboratories focused on response to COVID-19, with funding provided by the Coronavirus Aid, Relief, and Economic Security, or CARES, Act.

Pacific Northwest National Laboratory draws on its distinguishing strengths in chemistry, Earth sciences, biology and data science to advance scientific knowledge and address challenges in sustainable energy and national security. Founded in 1965, PNNL is operated by Battelle for the U.S. Department of Energy's Office of Science, which is the single largest supporter of basic research in the physical sciences in the United States. DOE's Office of Science is working to address some of the most pressing challenges of our time. For more information, visit PNNL's News Center. Follow us on Twitter, Facebook, LinkedIn, and Instagram.

FIRST AID 101

Increased tourniquet use has saved lives in Los Angeles County

The rise of prehospital tourniquet use has improved injured patients' survival and decreased the need for blood transfusions

AMERICAN COLLEGE OF SURGEONS

Key takeaways

• Tourniquet use has been consistently increasing in Los Angeles County since 2015 and is significantly associated with improved patient survival.
• Tourniquet use is safe and does not lead to increased risk of amputation with proper surgical care after arriving at the hospital.
• Findings are specific to Los Angeles County, where patients who had a tourniquet placed were able to be transported quickly to a trauma center for further life-saving care.

CHICAGO (April 22, 2021): Uncontrolled bleeding continues to be one of the most common causes of preventable death from a traumatic injury.1 However, patient survival from such injuries has improved in Los Angeles County due to an increased use of tourniquets to help stop severe bleeding before a patient arrives at a hospital. Findings appear in a Journal of the American College of Surgeons study published online in advance of print.

Researchers from the University of Southern California, Los Angeles set out to determine whether tourniquet use was increasing over time at the local level, specifically in Los Angeles County, and whether the use of tourniquets to control bleeding before a patient arrives at a hospital is associated with improved patient outcomes without complications. This study is believed to be the first of its kind, capturing tourniquet use data for an entire region, according to the authors.
"In Los Angeles County, the use of prehospital tourniquets for patients with extremity vascular injuries is increasing," the researchers concluded. "Its use is significantly associated with improved survival and a decreased blood transfusion requirement, without an increased risk of delayed amputation."
Tourniquets have previously been used more in the armed forces, but have become increasingly accepted in civilian life in recent years due to their effectiveness at reducing death after an injury. Although tourniquets had once fallen out of favor over concerns of complications, recent studies have shown they are largely safe with proper surgical care after arriving at the hospital.2
"What appears consistent across recent studies is that tourniquet use does not appear to be associated with an increased risk of delayed amputation, even with tourniquet times of over two hours," the authors note.
Study details
The researchers conducted a retrospective study from October 2015 to July 2019, including 944 patients in the study, 97 of which had a prehospital tourniquet placed before arriving at the hospital. Data on tourniquet placement by an EMS provider or a member of the public were not captured. Data were pulled from the Emergency Medical Services (EMS) provider registry and the trauma registry of the Los Angeles County Department of Health Services (LAC-DHS) EMS Agency. The patients included were trauma patients who were transported by EMS to one of the 15 Level I or Level II trauma centers in Los Angeles County.
The researchers compared two groups in the study, those with a prehospital tourniquet (PHTQ) placed with those who had no-tourniquet (no-PHTQ) placed. The average hospital length of stay, intensive care unit (ICU) length of stay, and delayed amputation rates were similar for both groups. Key differences include the following:

• In-hospital mortality was significantly higher in the no-PHTQ group (1 percent for PHTQ vs 8.9 percent for no-PHTQ)
• Prehospital tourniquet use was significantly associated with lower blood transfusion requirements at four hours and 24 hours (1 liter of blood needed at four hours and 2.5 liters at 24 hours for non-tourniquet patients and about a half-liter and one liter, respectively, for tourniquet patients)

"A higher number of tourniquets placed was associated with improved mortality and decreased requirements for transfusions and no difference in the rate of amputations," said lead study author Reynold Henry, MD, MPH, general surgery chief resident at LAC+USC Medical Center.
Importance of trauma center access
Although the researchers found a significant relationship between the use of tourniquets and an improvement in patient survival, they noted these findings are specific to Los Angeles County, where access to a trauma center is much more readily available than many rural areas in the U.S.
"The average transport time to a trauma center in Los Angeles County is around 10 to 15 minutes, which is quite short compared to other areas of the country, especially rural areas," said Kazuhide Matsushima, MD, FACS, assistant professor of surgery in the division of acute care surgery, LAC+USC Medical Center.
STOP THE BLEED® saves lives
One of the factors behind the increase in prehospital tourniquet use is STOP THE BLEED®, a public awareness campaign aimed at empowering the public by teaching bleeding control techniques--applying a tourniquet, applying pressure, or packing a wound--in communities across the U.S. and around the world. Dr. Henry and Dr. Matsushima stressed the importance of widespread tourniquet availability and public knowledge of bleeding control techniques. By knowing how to control bleeding, members of the public can become empowered to save a life.
"We'd like to encourage the public to think about this as a very simple intervention that anyone can do after a very simple training. Anyone can save a life," said Dr. Matsushima.
An important aspect of spreading this knowledge is governmental legislation that enhances the reach and lifesaving ability of STOP THE BLEED®.
"On a local, state, and federal level, policy needs to reflect that getting tourniquets into public spaces and mandatory STOP THE BLEED® training for certain types of jobs can go a long way. That is something we, as surgeons, should be advocating for," Dr. Henry said.

For more information about STOP THE BLEED® training, visit http://www.stopthebleed.org.

Other study authors are Cameron Ghafil, MD; Rachel N. Henry, BA; Hailey Theeuwen, MD; Adam C. Golden, MD, MPH; Tiffany M. Abramson, MD; and Kenji Inaba, MD, FACS.
"FACS" designates that a surgeon is a Fellow of the American College of Surgeons.
None of the authors have any conflicts of interest to disclose.
Citation: An Increasing Use of Prehospital Tourniquets and Patient Survival: A Los Angeles Countywide Study. Journal of the American College of Surgeons. DOI: https://doi.org/10.1016/j.jamcollsurg.2021.03.023. _________________ 1 Kauvar DS, Lefering R, Wade CE. Impact of Hemorrhage on Trauma Outcome: An Overview of Epidemiology, Clinical Presentations, and Therapeutic Considerations. J Trauma Acute Care. 2006;60(6). 2 Smith AA, Ochoa JE, Wong S, et al. Prehospital tourniquet use in penetrating extremity trauma: Decreased blood transfusions and limb complications. J Trauma Acute Care Surg. 2019 Jan;86(1):43-51.

About the American College of Surgeons

The American College of Surgeons is a scientific and educational organization of surgeons that was founded in 1913 to raise the standards of surgical practice and improve the quality of care for all surgical patients. The College is dedicated to the ethical and competent practice of surgery. Its achievements have significantly influenced the course of scientific surgery in America and have established it as an important advocate for all surgical patients. The College has more than 82,000 members and is the largest organization of surgeons in the world. For more information, visit http://www.facs.org

Salad or cheeseburger? Your co-workers shape your food choices

People in our social networks influence the food we eat -- both healthy and unhealthy -- according to a large study of hospital employees; the findings may guide efforts to improve population health

WE ALL HAVE TWO FAMILIES;

ONE AT HOME THE OTHER AT WORK

MASSACHUSETTS GENERAL HOSPITAL

Research News

 

BOSTON -- The foods people buy at a workplace cafeteria may not always be chosen to satisfy an individual craving or taste for a particular food. When co-workers are eating together, individuals are more likely to select foods that are as healthy--or unhealthy--as the food selections on their fellow employees' trays. "We found that individuals tend to mirror the food choices of others in their social circles, which may explain one way obesity spreads through social networks," says Douglas Levy, PhD, an investigator at the Mongan Institute Health Policy Research Center at Massachusetts General Hospital (MGH) and first author of new research published in Nature Human Behaviour. Levy and his co-investigators discovered that individuals' eating patterns can be shaped even by casual acquaintances, evidence that corroborates several multi-decade observational studies showing the influence of people's social ties on weight gain, alcohol consumption and eating behavior.

Previous research on social influence upon food choice had been primarily limited to highly controlled settings like studies of college students eating a single meal together, making it difficult to generalize findings to other age groups and to real-world environments. The study by Levy and his co-authors examined the cumulative social influence of food choices among approximately 6,000 MGH employees of diverse ages and socioeconomic status as they ate at the hospital system's seven cafeterias over two years. The healthfulness of employees' food purchases was determined using the hospital cafeterias' "traffic light" labeling system designating all food and beverages as green (healthy), yellow (less healthy) or red (unhealthy).

MGH employees may use their ID cards to pay at the hospitals' cafeterias, which allowed the researchers to collect data on individuals' specific food purchases, and when and where they purchased the food. The researchers inferred the participants' social networks by examining how many minutes apart two people made food purchases, how often those two people ate at the same time over many weeks, and whether two people visited a different cafeteria at the same time. "Two people who make purchases within two minutes of each other, for example, are more likely to know each other than those who make purchases 30 minutes apart," says Levy. And to validate the social network model, the researchers surveyed more than 1,000 employees, asking them to confirm the names of the people the investigators had identified as their dining partners.

"A novel aspect of our study was to combine complementary types of data and to borrow tools from social network analysis to examine how the eating behaviors of a large group of employees were socially connected over a long period of time," says co-author Mark Pachucki, PhD, associate professor of Sociology at the University of Massachusetts, Amherst.

Based on cross-sectional and longitudinal assessments of three million encounters between pairs of employees making cafeteria purchases together, the researchers found that food purchases by people who were connected to each other were consistently more alike than they were different. "The effect size was a bit stronger for healthy foods than for unhealthy foods," says Levy.

A key component of the research was to determine whether social networks truly influence eating behavior, or whether people with similar lifestyles and food preferences are more likely to become friends and eat together, a phenomenon known as homophily. "We controlled for characteristics that people had in common and analyzed the data from numerous perspectives, consistently finding results that supported social influence rather than homophily explanations," says Levy.

Why do people who are socially connected choose similar foods? Peer pressure is one explanation. "People may change their behavior to cement the relationship with someone in their social circle," says Levy. Co-workers may also implicitly or explicitly give each other license to choose unhealthy foods or exert pressure to make a healthier choice.

The study's findings have several broader implications for public health interventions to prevent obesity. One option may be to target pairs of people making food choices and offer two-for-one sales on salads and other healthful foods but no discounts on cheeseburgers. Another approach might be to have an influential person in a particular social circle model more healthful food choices, which will affect others in the network. The research also demonstrates to policymakers that an intervention that improves healthy eating in a particular group will also be of value to individuals socially connected to that group.

"As we emerge from the pandemic and transition back to in-person work, we have an opportunity to eat together in a more healthful way than we did before," says Pachucki. "If your eating habits shape how your co-workers eat--even just a little--then changing your food choices for the better might benefit your co-workers as well."

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Levy is an associate professor of Medicine at Harvard Medical School (HMS). Pachucki is associate professor of Sociology at the UMass Computational Social Science Institute. A. James O'Malley, PhD, is professor of Biostatistics at the Dartmouth Institute and the Department of Biomedical Data Science at the Geisel School of Medicine at Dartmouth. Anne Thorndike, MD, MPH, is an investigator in the Division of General Internal Medicine at MGH and associate professor of Medicine at HMS.

Major funding was provided by the National Institute of Diabetes and Digestive and Kidney Diseases and the National Heart Lung and Blood Institute.

About the Massachusetts General Hospital

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In August 2020, Mass General was named #6 in the U.S. News & World Report list of "America's Best Hospitals."

The first US population to experience drone delivery gives it a seal of approval

VIRGINIA TECH

Research News

 

IMAGE: THE DRONE-DELIVERY SERVICE IN CHRISTIANSBURG, VA. -- THE FIRST IN THE COUNTRY TO DELIVER GOODS DIRECTLY TO RESIDENCES ON DEMAND -- GAVE RESEARCHERS A UNIQUE OPPORTUNITY TO STUDY HOW PEOPLE... view more 

CREDIT: VIRGINIA TECH

The week of Thanksgiving last year, a postcard arrived in mailboxes in Christiansburg. A link to a survey was on the back. On the front, there was a picture that was, by then, very familiar to the residents of a town that made history in 2019 as the first place in the U.S. to have a residential drone delivery service: a yellow-winged drone with a small cardboard box tucked underneath it.

The survey's 20 questions were designed to measure how Christiansburg's 22,000 residents felt about drone delivery -- the first time that this question had ever been posed to a community that had actually experienced the service. The survey was developed and conducted by researchers from the Virginia Tech Mid-Atlantic Aviation Partnership (MAAP), a federally designated drone test site, and Lee Vinsel, an assistant professor of science, technology, and society in the College of Liberal Arts and Human Sciences.

The primary finding: 87 percent of people who responded to the survey reported that they liked the idea of drone delivery. The resoundingly positive results, published in the spring issue of Issues in Science and Technology, plant a new stake in the ground for the future of a technology still at the beginning of its transition from research to retail.

Interest in drone delivery is rising. The service in Christiansburg, run by Wing, Alphabet's drone-delivery subsidiary, is the most advanced of the handful of trial services operating today. But drone technology -- and the laws that regulate it -- are maturing, and it's expected that services like these could become routine in the next few years.

Whether they're successful or not will depend in large part on how the public responds. Delivering packages to homes unfolds in the public eye to a greater extent than many other applications for drones: People may see the drone in the commercial area where it picks up its cargo, at the customer's house, and in the neighborhoods in between.

Accurate estimates of public opinion are critical for the regulatory agencies developing rules that will govern its use and state and local governments considering whether to encourage it, in addition to the companies pioneering these services and hoping to scale their businesses.

Until now, though, data has been limited, and usually not encouraging: The handful of surveys on this topic have pegged public support for drone delivery at around 50 percent in the U.S. and lower in Europe and the U.K..

But several factors suggest that those anemic results might not be definitive.

First, crucially, these surveys polled people who had almost certainly never received a delivery by drone, and were speculating about a service they were imagining rather than reporting on one they'd experienced. Second, many of the survey questions frame their questions in a way that implies risk, asking respondents to rate their level of concern about potential problems selected by the researchers in advance. Highlighting potential negative outcomes may prompt a more negative overall sentiment.

Christiansburg, then, represented a unique research opportunity.

"Gauging people's reactions to new technologies can be really difficult, including because it's so easy to bias respondents' views," Vinsel said. "We wanted to create a survey that was as neutral as possible to examine sentiments about drone delivery. And Christiansburg was a great opportunity for us because it was a unique population that had actually experienced these systems."

The survey asked respondents about standard demographic factors and their typical response to new technologies. It asked about how familiar they were with drone delivery, how they'd found out about it, and what their general attitude toward it was. Instead of asking about specific risks and benefits, the researchers asked open-ended questions about what the respondents saw as positive and negative aspects of the technology.

The survey was approved by the Virginia Tech Institutional Review Board; Wing helped fund the survey development and distribution through an existing research contract with MAAP, but the analysis was funded entirely by Virginia Tech. Adeline Guthrie, a graduate student in the statistics in the College of Science and collaborator with the Statistical Applications and Innovations Group, assisted with data analysis.

The results were resoundingly positive.

Not only did 87 percent of respondents report positive sentiment about drone delivery, 89 percent indicated either that they were likely to use the service or already had, and 49 percent reported liking the idea of drones used for package delivery more than drones used for other purposes.

All of these results are dramatically different from those of other surveys, in which positive sentiment never exceeded 51 percent and delivery was a relatively unpopular application when ranked against others.

The survey also asked respondents if their opinion had changed since the pandemic. When COVID-19 hit Virginia in March, the number of people signing up for Wing's service and ordering drone deliveries spiked. Wing partnered with additional local businesses and worked with a school librarian to deliver books.

The survey results suggested that these contributions had helped. The pandemic popped up frequently in the open-ended question about positive aspects of the technology. Fifty-eight percent of Christiansburg survey respondents said that their opinion of drone delivery had improved -- a much bigger boost than was measured in a 2020 survey from the Consumer Technology Association that polled a general population sample.

Here again, Christiansburg residents' experience with drone delivery may have contributed to the jump -- seeing a favorite coffee shop find a new way to reach customers without in-person shopping or a neighbor's child receiving a delivery of sidewalk chalk and crackers, may resonate more than an abstract appreciation for contact-free delivery.

MAAP worked with Wing to launch the drone delivery program under the federal UAS Integration Pilot Program, a drone-integration initiative that brought together state agencies, local governments, and companies to advance the rollout of drone applications that could have significant benefits for communities (the trial is continuing under the IPP successor program BEYOND). MAAP and Wing conducted months of community outreach before the service launched, talking to thousands of Christiansburg residents about what the service would look like.

"One of the goals of the IPP was to take a community-oriented approach to drone integration," said Tombo Jones, MAAP's director. "There's not a shortcut here. You need careful, methodical research to demonstrate that the system is safe and reliable. Then you can take that information out into the community, and talk to people to learn what they're looking for and what their concerns are. It's rewarding to see how positive the results of this survey are, because they show that, when it's done the right way, developing new applications for drones can have a genuinely positive impact on a community."

The team is hoping that future research will reveal more detail about how people's opinions evolve before and after they're exposed to drone delivery, the aspects of drone delivery that inspire the greatest enthusiasm or strongest skepticism, and what factors help determine how someone will feel about the technology.

"The key thing is that speculation about technologies is different than actual experiences with them," Vinsel said. "Lots of factors influence how we feel about the technologies in our lives, but something scholars have found repeatedly over for the last 60 years is that familiarity breeds acceptance. To be at an early point in the rollout of this technology and be able to study a population that has actually experienced it is pretty exciting."

Average-risk individuals may prefer stool-based test over colonoscopy for cancer screening

HAVING HAD BOTH I WILL TAKE THE TEST OVER THE SCREENING

AMERICAN ASSOCIATION FOR CANCER RESEARCH

Research News

 

Bottom Line: When given a choice, most individuals with an average risk of colorectal cancer said they would prefer a stool-based screening test for colorectal cancer over colonoscopy, the method most often recommended by health care providers.

Journal in Which the Study was Published: Cancer Prevention Research, a journal of the American Association for Cancer Research

Author: Xuan Zhu, PhD, senior health services analyst at the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery

Background: Although colorectal cancer is the second most frequent cause of cancer-related death in the United States, about one-third of eligible American adults have never completed a colorectal cancer screening test, explained lead author Zhu. Zhu added that colorectal cancer screening is particularly underutilized by individuals experiencing socioeconomic disadvantages, racial and ethnic minorities, and certain age groups.

The U.S. Preventive Services Task Force (USPSTF) recommends several colorectal cancer screening methods for adults ages 50 to 75 with an average risk for this disease, and the USPSTF draft guideline update released in October 2020 recommends lowering the age of screening initiation to 45. The three most common tests are an annual fecal immunochemical test or fecal occult blood test (FIT/FOBT) that detects blood in the stool; the multitarget stool DNA (mt-sDNA) test (Cologuard), completed every three years, which detects altered DNA from cancer cells, precancerous polyps, or blood in the stool; and a colonoscopy every 10 years, which involves a gastroenterologist examining the colon with a camera and removing any precancerous polyps while a patient is under sedation.

"Previous research has shown that fewer patients complete colorectal cancer screening when only colonoscopy is recommended compared to when stool-based options are also recommended," said Zhu.

How the Study was Conducted: In this study, Zhu and colleagues evaluated patient preferences for colorectal cancer screening through a survey conducted in collaboration with the National Opinion Research Center at the University of Chicago. The survey included short descriptions of FIT/FOBT, mt-sDNA, and colonoscopy, and asked a nationally representative sample of adults ages 40 to 75 to choose between two options presented at a time. A total of 1,595 respondents completed the survey. The researchers focused their analysis on a subgroup of 1,062 respondents aged 45 to 75 with an average risk of colorectal cancer.

Results: When presented with a choice, 66 percent of respondents said they preferred mt-sDNA over colonoscopy, and 61 percent said they preferred FIT/FOBT over colonoscopy. When asked to choose between the two stool-based options, 67 percent indicated a preference for mt-sDNA over FIT/FOBT.

The investigators also examined differences in patient preferences across sociodemographic characteristics, access to health care, awareness of colorectal cancer screening, and prior experience completing a test. While mt-sDNA was preferred over colonoscopy for all age groups examined, a larger proportion of older adults (ages 65 to 75 years) said they preferred colonoscopy compared to those in younger age groups (ages 45 to 54 years).

Similarly, the preference for mt-sDNA over colonoscopy was higher among non-Hispanic white individuals compared with non-Hispanic Black and Hispanic individuals. Half of Hispanic and non-Hispanic Black respondents preferred stool-based tests over colonoscopy, with a preference for mt-sDNA over FIT/FOBT. Zhu said the observed differences among age and racial/ethnic groups might have reflected variations in preferences or disparities in access to information about newer testing methods.

Respondents without insurance were 2.5 times more likely to prefer less expensive stool-based tests over colonoscopy. The overall awareness of stool-based tests was about 60 percent, compared to 90 percent for colonoscopy, indicating that there is an opportunity to improve patient education about stool-based options, Zhu noted. Study participants who were aware of stool-based tests were two times more likely to prefer mt-sDNA over FIT/FOBT, and those who had previously had a stool-based test were 2.8 times more likely to choose FIT/FOBT over colonoscopy. By contrast, those who had previously had a colonoscopy were less than half as likely to prefer a stool-based test over colonoscopy and those who had a provider recommend colonoscopy in the past 12 months were 40 percent less likely to prefer mt-sDNA over colonoscopy.

Author's Comments: "The best colorectal cancer screening test is the one that patients are most likely to complete," Zhu said.

The findings highlight the importance of patient education about available screening options and taking patients' needs, preferences, and values into account in shared decision-making discussions to increase colorectal cancer screening rates, Zhu added. "Providing patients with as-needed navigation support, from initiation of screening to completion of a colonoscopy after stool-based tests show abnormal results may increase screening completion and adherence."

Study Limitations: Limitations of this study include the observational design, meaning that causal relationships cannot be inferred, the reliance on self-reported data rather than objective measures, and limiting the scope of the study to the three colorectal cancer screening tests most commonly recommended by health care providers.

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Funding & Disclosures: The study was supported by funding provided by Exact Sciences Corporation and the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery. Zhu declares no conflicts of interest.

About the American Association for Cancer Research

Founded in 1907, the American Association for Cancer Research (AACR) is the world's first and largest professional organization dedicated to advancing cancer research and its mission to prevent and cure cancer. AACR membership includes 48,000?laboratory, translational, and clinical researchers; population scientists; other health care professionals; and patient advocates residing in 127 countries. The AACR marshals the full spectrum of expertise of the cancer community to accelerate progress in the prevention, diagnosis, and treatment of cancer by annually convening more than 30 conferences and educational workshops--the largest of which is the AACR Annual Meeting, with more than 74,000 attendees for the 2020 virtual meetings and more than 22,500 attendees for past in-person meetings. In addition, the AACR publishes nine prestigious, peer-reviewed scientific journals and a magazine for cancer survivors, patients, and their caregivers. The AACR funds meritorious research directly as well as in cooperation with numerous cancer organizations. As the Scientific Partner of Stand Up To Cancer, the AACR provides expert peer review, grants administration, and scientific oversight of team science and individual investigator grants in cancer research that have the potential for near-term patient benefit. The AACR actively communicates with legislators and other policymakers about the value of cancer research and related biomedical science in saving lives from cancer. For more information about the AACR, visit?http://www.AACR.org.

The science of spin -- asteroseismologists confirm older stars rotate faster than expected

UNIVERSITY OF BIRMINGHAM

Research News

 

IMAGE:  "SOUND WAVES TRAPPED INSIDE STARS CAUSE THEM TO OSCILLATE AT PARTICULAR FREQUENCIES. THESE VIBRATIONS ARE VISIBLE ON THE SURFACE, AND CAN BE MEASURED BY ASTRONOMERS USING SPACE TELESCOPES. WHEN A... view more 

CREDIT: MARK GARLICK / UNIVERSITY OF BIRMINGHAM

Stars spin faster than expected as they age according to a new study led by scientists at the University of Birmingham which uses asteroseismology to shed new light on this emerging theory.

All stars, like the Sun, are born spinning. As they grow older, their spin slows down due to magnetic winds in a process called 'magnetic braking'. Research published in 2016 by scientists at Carnegie Observatories delivered the first hints that stars at a similar stage of life as the Sun were spinning faster than magnetic braking theories predicted. The results from this study were based on a method in which scientists pinpoint dark spots on the surface of stars and track them as they move with the stars' spin. While the method has proven robust for measuring spin in younger stars, however, older stars have fewer star spots, which has made the effects of this "weakened" magnetic braking on these stars hard to confirm.

In a new study, published in Nature Astronomy, researchers at the University of Birmingham used a different approach to confirm that older stars do, in fact, appear to rotate faster than expected. The team used asteroseismology to calculate how the star is rotating. This relatively new field of study enables scientists to measure the oscillations caused by sound waves trapped inside the star. By measuring the different characteristics of these waves, they can reveal different characteristics of stars, such as their size or age.

In this study, the team measured the modes, or the frequencies, of the sound waves produced by the star's oscillation. As the star spins, these modes split into different frequencies. This can be imagined, the author's say, as the sound of two ambulances stood still on a roundabout compared to when they are driving in circles. By measuring these frequencies, it is possible to calculate the rate of spin in a way that is possible for both young and old stars.

Lead author on the paper, Dr Oliver Hall, said: "Although we've suspected for some time that older stars rotate faster than magnetic braking theories predict, these new asteroseismic data are the most convincing yet to demonstrate that this 'weakened magnetic braking' is actually the case. Models based on young stars suggest that the change in a star's spin is consistent throughout their lifetime, which is different to what we see in these new data."

One aspect the researchers believe could be key to the change in momentum loss, is changes to the star's magnetic field. Understanding how the magnetic field interacts with rotation will be an important area of future study, and is being worked on by authors on the paper.

The results could also shed light on our own star's activity over the next several billion years, explains co-author Dr Guy Davies: "These new findings demonstrate that we still have a lot to learn about the future of our own Sun as well as other stars. This work helps place in perspective whether or not we can expect reduced solar activity and harmful space weather in the future. To answer these questions we need better models of solar rotation, and this work takes an important step towards improving the models and supplying the data needed to test them."

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Other contributors to the study include the European Space Agency (ESA), Aarhus University, University of Hawai'i, Universit´e Paris-Saclay, and the University of Exeter.

Know your ally: Cooperative male dolphins can tell who's on their team

UNIVERSITY OF BRISTOL

Research News

 

IMAGE: THREE MALE DOLPHINS AND ONE FEMALE view more 

CREDIT: DR SIMON ALLEN

When it comes to friendships and rivalries, male dolphins know who the good team players are. New findings, published in Nature Communications by University of Bristol researchers, reveal that male dolphins form a social concept of team membership based on cooperative investment in the team.

The Bristol researchers, with colleagues from the University of Zurich and University of Massachusetts, used 30 years of observational data from a dolphin population in Shark Bay, Western Australia, and sound playback experiments to assess how male dolphins responded to the calls of other males from their alliance network.

Dr Stephanie King, Senior Lecturer from Bristol's School of Biological Sciences who led the research, said: "Social animals can possess sophisticated ways of classifying relationships with members of the same species. In our own society, we use social knowledge to classify individuals into meaningful groups, like sports teams and political allies. Bottlenose dolphins form the most complex alliances outside humans, and we wanted to know how they classify these relationships."

Dr Simon Allen, Research Fellow at Bristol's School of Biological Sciences, who contributed to the study, added: "We flew drones above dolphin groups, recording their behaviour during the sound playbacks, tracking their movements underwater and revealing novel insights into how dolphins respond to the calls of other males in their network of allies."

Males responded strongly to all of the allies that had consistently helped them out in the past, even if they weren't currently close friends. On the other hand, they didn't respond strongly to males who hadn't consistently helped them out in the past, even if they were friends. What this shows is that these dolphins form social concepts of 'team membership', categorizing allies according to a shared cooperative history.

Dr King said: "Such concepts develop through experience and likely played a role in the cooperative behaviour of early humans. Our results show that cooperation-based concepts are not unique to humans, but also occur in other animal societies with extensive cooperation between non-kin."

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The study was funded by The Branco Weiss Fellowship - Society in Science and the National Geographic Society.

ALMA discovers rotating infant galaxy with help of natural cosmic telescope

NATIONAL INSTITUTES OF NATURAL SCIENCES

Research News

 

IMAGE: IMAGE OF THE GALAXY CLUSTER RXCJ0600-2007 TAKEN BY THE NASA/ESA HUBBLE SPACE TELESCOPE, COMBINED WITH GRAVITATIONAL LENSING IMAGES OF THE DISTANT GALAXY RXCJ0600-Z6, 12.4 BILLION LIGHT-YEARS AWAY, OBSERVED BY ALMA... view more 

CREDIT: ALMA (ESO/NAOJ/NRAO), FUJIMOTO ET AL., NASA/ESA HUBBLE SPACE TELESCOPE

Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers found a rotating baby galaxy 1/100th the size of the Milky Way at a time when the Universe was only seven percent of its present age. Thanks to assistance by the gravitational lens effect, the team was able to explore for the first time the nature of small and dark "normal galaxies" in the early Universe, representative of the main population of the first galaxies, which greatly advances our understanding of the initial phase of galaxy evolution.

"Many of the galaxies that existed in the early Universe were so small that their brightness is well below the limit of the current largest telescopes on Earth and in Space, making difficult to study their properties and internal structure," says Nicolas Laporte, a Kavli Senior Fellow at the University of Cambridge. "However, the light coming from the galaxy named RXCJ0600-z6, was highly magnified by gravitational lensing, making it an ideal target for studying the properties and structure of a typical baby galaxies."

Gravitational lensing is a natural phenomenon in which light emitted from a distant object is bent by the gravity of a massive body such as a galaxy or a galaxy cluster located in the foreground. The name "gravitational lensing" is derived from the fact that the gravity of the massive object acts like a lens. When we look through a gravitational lens, the light of distant objects is intensified and their shapes are stretched. In other words, it is a "natural telescope" floating in space.

The ALMA Lensing Cluster Survey (ALCS) team used ALMA to search for a large number of galaxies in the early Universe that are enlarged by gravitational lensing. Combining the power of ALMA, with the help of the natural telescopes, the researchers are able to uncover and study fainter galaxies.

Why is it crucial to explore the faintest galaxies in the early Universe? Theory and simulations predict that the majority of galaxies formed few hundred millions years after the Big-Bang are small, and thus faint. Although several galaxies in the early Universe have been previously observed, those studied were limited to the most massive objects, and therefore the less representative galaxies, in the early Universe, because of telescopes capabilities. The only way to understand the standard formation of the first galaxies, and obtain a complete picture of galaxy formation, is to focus on the fainter and more numerous galaxies.

The ALCS team performed a large-scale observation program that took 95 hours, which is a very long time for ALMA observations, to observe the central regions of 33 galaxy clusters that could cause gravitational lensing. One of these clusters, called RXCJ0600-2007, is located in the direction of the constellation of Lepus, and has a mass 1000 trillion times that of the Sun. The team discovered a single distant galaxy that is being affected by the gravitational lens created by this natural telescope. ALMA detected the light from carbon ions and stardust in the galaxy and, together with data taken with the Gemini telescope, determined that the galaxy is seen as it was about 900 million years after the Big Bang (12.9 billion years ago). Further analysis of these data suggested that a part of this source is seen 160 times brighter than it is intrinsically.

By precisely measuring the mass distribution of the cluster of galaxies, it is possible to "undo" the gravitational lensing effect and restore the original appearance of the magnified object. By combining data from Hubble Space Telescope and the European Southern Observatory's Very Large Telescope with a theoretical model, the team succeeded in reconstructing the actual shape of the distant galaxy RXCJ0600-z6. The total mass of this galaxy is about 2 to 3 billion times that of the Sun, which is about 1/100th of the size of our own Milky Way Galaxy.

What astonished the team is that RXCJ0600-z6 is rotating. Traditionally, gas in the young galaxies was thought to have random, chaotic motion. Only recently has ALMA discovered several rotating young galaxies that have challenged the traditional theoretical framework, but these were several orders of magnitude brighter (larger) than RXCJ0600-z6.

"Our study demonstrates, for the first time, that we can directly measure the internal motion of such faint (less massive) galaxies in the early Universe and compare it with the theoretical predictions", says Kotaro Kohno, a professor at the University of Tokyo and the leader of the ALCS team.

"The fact that RXCJ0600-z6 has a very high magnification factor also raises expectations for future research," explains Seiji Fujimoto, a DAWN fellow at the Niels Bohr Institute. "This galaxy has been selected, among hundreds, to be observed by the James Webb Space Telescope (JWST), the next generation space telescope to be launched this autumn. Through joint observations using ALMA and JWST, we will unveil the properties of gas and stars in a baby galaxy and its internal motions. When the Thirty Meter Telescope and the Extremely Large Telescope are completed, they may be able to detect clusters of stars in the galaxy, and possibly even resolve individual stars. There is an example of gravitational lensing that has been used to observe a single star 9.5 billion light-years away, and this research has the potential to extend this to less than a billion years after the birth of the Universe."

These observation results were presented in Seiji Fujimoto et al. "ALMA Lensing Cluster Survey: Bright [CII] 158 μm Lines from a Multiply Imaged Sub-L* Galaxy at z = 6.0719" in the Astrophysical Journal on April 22, 2021, and Nicolas Laporte et al. "ALMA Lensing Cluster Survey: a strongly lensed multiply imaged dusty system at z > 6" in the Monthly Notices of the Royal Astronomical Society on April 22, 2021.

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