Recent advances in silver nanoparticle research

Peer-Reviewed Publication

AMERICAN CHEMICAL SOCIETY

Glittery metallic decorations keep the winter season cozy and bright. And silver jewelry adds to the glitz and glamour of holiday parties. However, microscopic particles of this metal have other unique properties, such as high electrical conductivity and antimicrobial activity, that researchers have applied to materials and biomedical products. Below are some recent papers published in ACS journals that report insights into how silver nanoparticles can be used to construct personal heaters, disinfect water and detect foodborne toxins. Reporters can request free access to these papers by emailing newsroom@acs.org.

“Ag Nanoparticles-Coated Shish-Kebab Superstructure Film for Wearable Heater”
ACS Applied Materials & Interfaces
Dec. 1, 2023
Traditional and synthetic polymer fibers don’t naturally produce their own heat. So, these authors present a method to adhere silver nanoparticles to polyethylene — a polymer used in some textiles and fabrics. They prepared a polyethylene film with microscopic structures similar to beads along a string, and then coated it in polydopamine followed by a spray of silver nanoparticles. Compared to cotton, this film rapidly warmed under simulated sunlight and when an electrical current was applied. The researchers say that these features make the nanomaterial an excellent candidate for wearable heaters.

“Integrating Navajo Pottery Techniques to Improve Silver Nanoparticle-Enabled Ceramic Water Filters for Disinfection”
Environmental Science & Technology
Oct. 23, 2023
Here, researchers mixed silver nanoparticles into a substance normally used as a coating for Navajo pottery and incorporated that coating in an antibacterial ceramic water filter. First, a Navajo potter heated pinyon pine resin in a traditional process, producing a substance called rosin, and then the team of researchers dissolved silver nanoparticles in the rosin. They applied a thin layer of the mixture onto a porous ceramic cartridge. When filtering water, the coated cartridges released dissolved silver ions at levels that inactivated bacteria but are considered safe for consumption. The new water treatment system was highly effective for at least 25 days.

“Characterizing a Silver Nanoparticle-Based Electrochemical Biosensor for Shiga Toxin Detection”
ACS Omega
Oct. 18, 2023
Not all E. coli bacteria cause foodborne illness, but consuming the strains that produce Shiga toxin can lead to gastrointestinal distress and, in severe cases, organ damage. But assessing food and water for this toxin requires complex, expensive techniques. As a step towards a simpler test, scientists coated silver nanoparticles in Shiga toxin antibodies and used them in an electrochemical assay. The new method’s performance was similar to current immunoassay and PCR techniques, a result that’s promising for creating an inexpensive detection tool, the researchers say.

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The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

Note: ACS does not conduct research, but publishes and publicizes peer-reviewed scientific studies.

Upcycling leftover cardboard to make a new type of foam packaging

Peer-Reviewed Publication

AMERICAN CHEMICAL SOCIETY

 

IMAGE: 

THIS CARDBOARD-BASED FOAM REINFORCED WITH GELATIN COULD MAKE PACKAGING MATERIALS MORE SUSTAINABLE.

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CREDIT: JINSHENG GOU

With the holiday season in full swing, gifts of all shapes and sizes are being shipped around the world. But all that packaging generates lots of waste, including cardboard boxes and plastic-based foam cushioning, such as Styrofoam™. Rather than discard those boxes, researchers publishing in ACS Sustainable Chemistry & Engineering developed a cushioning foam from cardboard waste. Their upcycled material was stronger and more insulating than traditional, plastic foam-based cushioning.

Among the many kinds of trash that accumulate within a home, wastepaper is one of the most common. Everything from newspapers and junk mail to paperboard envelopes and cardboard boxes can pile up, especially as internet shopping has exploded in popularity. Researchers are interested in turning these containers and paper waste into something else that’s useful — sturdy but light mailing materials. Currently, to keep electronics and toys nestled tightly inside of a box, molded cushioning materials, such as Styrofoam, are typically used. A sustainable alternative could be lightweight, cellulose aerogels, but current methods to produce them from wastepaper require several chemical pretreatment steps. So, Jinsheng Gou and colleagues wanted to find a simpler way to make a wastepaper-based foam material that could withstand the roughest of deliveries.

To create their foam, the team broke down cardboard scraps in a blender to create a pulp, then mixed it with either gelatin or polyvinyl acetate (PVA) glue. The mixtures were poured into molds, refrigerated, then freeze-dried to form cushioning foams. Both paper-based foams served as good thermal insulators and strong energy absorbers — even better than some plastic foams. The team then created a heavy-duty version of their wastepaper foam by combining the pulp, gelatin, PVA glue, and a silica-based fluid that hardens as force is applied. This version of the cardboard-based foam withstood hits from a hammer without falling apart, and that result suggests the foam could be used in force-intensive deliveries, such as parachute-free airdrops. The researchers say their work offers a simple yet efficient method to upcycle cardboard to create more environmentally friendly packaging materials.

The authors acknowledge funding from the Beijing Key Laboratory of Wood Science and Engineering.

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The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

Note: ACS does not conduct research, but publishes and publicizes peer-reviewed scientific studies.

Follow us: Twitter | Facebook | LinkedIn | Instagram

 

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JOURNAL

ACS Sustainable Chemistry & Engineering

DOI

10.1021/acssuschemeng.3c06230 

ARTICLE TITLE

Biodegradable Wastepaper-Based Foam with Ultrahigh Energy-Absorbing, Excellent Thermal Insulation, and Outstanding Cushioning Properties

Researchers find way to weld metal foam without melting its bubbles

Peer-Reviewed Publication

NORTH CAROLINA STATE UNIVERSITY

 

IMAGE: 

COMPOSITE METAL FOAMS (CMFS) ARE FOAMS THAT CONSIST OF HOLLOW, METALLIC SPHERES – MADE OF MATERIALS SUCH AS STAINLESS STEEL OR TITANIUM – EMBEDDED IN A METALLIC MATRIX MADE OF STEEL, TITANIUM, ALUMINUM OR OTHER METALLIC ALLOYS. THE RESULTING MATERIAL IS BOTH LIGHTWEIGHT AND REMARKABLY STRONG, WITH POTENTIAL APPLICATIONS RANGING FROM AIRCRAFT WINGS TO VEHICLE ARMOR AND BODY ARMOR. IN ADDITION, CMF IS BETTER AT INSULATING AGAINST HIGH HEAT THAN CONVENTIONAL METALS AND ALLOYS, SUCH AS STEEL. THE COMBINATION OF WEIGHT, STRENGTH AND THERMAL INSULATION MEANS THAT CMF ALSO HOLDS PROMISE FOR USE IN STORING AND TRANSPORTING NUCLEAR MATERIAL, HAZARDOUS MATERIALS, EXPLOSIVES AND OTHER HEAT-SENSITIVE MATERIALS. BUT TO REALIZE MANY OF THESE APPLICATIONS, MANUFACTURERS WOULD NEED TO WELD MULTIPLE CMF COMPONENTS TOGETHER. AND TRADITIONAL WELDING TECHNIQUES MELT THE BUBBLES THAT MAKE CMF DESIRABLE. RESEARCHERS HAVE NOW SHOWN THAT A TECHNIQUE CALLED INDUCTION WELDING, THAT RELIES ON ELECTROMAGNETIC FIELDS, CAN WELD CMFS WITHOUT IMPAIRING THE BUBBLES IN THE FOAM. THIS ILLUSTRATION SHOWS HOW IT WORKS. NOTE THAT THE CMF IS COOL ENOUGH TO TOUCH WITH YOUR BARE HAND, ONLY INCHES AWAY FROM THE SITE OF THE WELD.

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CREDIT: AFSANEH RABIEI, NC STATE UNIVERSITY

Researchers at North Carolina State University have now identified a welding technique that can be used to join composite metal foam (CMF) components together without impairing the properties that make CMF desirable. CMFs hold promise for a wide array of applications because the pockets of air they contain make them light, strong and effective at insulating against high temperatures.

CMFs are foams that consist of hollow, metallic spheres – made of materials such as stainless steel or titanium – embedded in a metallic matrix made of steel, titanium, aluminum or other metallic alloys. The resulting material is both lightweight and remarkably strong, with potential applications ranging from aircraft wings to vehicle armor and body armor.

In addition, CMF is better at insulating against high heat than conventional metals and alloys, such as steel. The combination of weight, strength and thermal insulation means that CMF also holds promise for use in storing and transporting nuclear material, hazardous materials, explosives and other heat-sensitive materials.

However, in order to realize many of these applications, manufacturers would need to weld multiple CMF components together. And that has posed a problem.

“Traditional fusion welding uses a filler to connect two pieces of metal,” says Afsaneh Rabiei, corresponding author of a paper on the new research and professor of mechanical and aerospace engineering at NC State. “This is problematic, because the metal being melted to fuse two pieces of CMF is solid, so it lacks the desirable properties of the CMF on either side of it. In addition, any type of welding that uses direct heat to melt the metal results in some of the porosity in the CMF being filled in, which impairs its properties. In short, that means that most forms of traditional welding don’t work well with metal foams.”

However, the researchers have now identified a form of welding that works very well. It’s called induction welding, and it uses an induction coil to create an electromagnetic field that heats the metal for welding.

“Because CMF is only 30-35% metal, the electromagnetic field is able to penetrate deeply into the material – allowing for a good weld,” Rabiei says. “The air pockets that make up the remaining 65-70% of the CMF serve to insulate the material against the heat. This allows induction welding to heat up the targeted area for joining two pieces of CMF, but prevents the heat from spreading out from the site of the join. That helps to preserve the CMF’s properties.

“This is an important step forward, because CMF’s properties make it attractive for a wide range of applications, but it’s essential to have a means of welding the CMF components without impairing the properties that make it attractive in the first place.”

The paper, “A Study on Welding of Porous Metals and Metallic Foams,” is published in the journal Advanced Engineering Materials. The paper was co-authored by John Cance and Zubin Chacko, Ph.D. students at NC State. The work was done with support from the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration, under grant number PH957-20-0075.

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JOURNAL

Advanced Engineering Materials

DOI

10.1002/adem.202301430 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

A Study on Welding of Porous Metals and Metallic Foams

ARTICLE PUBLICATION DATE

16-Nov-2023

COI STATEMENT

Afsaneh Rabiei is the inventor of composite metal foams. She has assigned her related IP to a small business in which she is a shareholder.

 

New app to bridge information gap between hospitals and nursing homes; better care for patients

Peer-Reviewed Publication

REGENSTRIEF INSTITUTE

INDIANAPOLIS – Approximately one in five older adults in the U.S. is transferred to a nursing home following a hospital stay. For many of these patients, an accessible medical record does not accompany them, often negatively affecting the care they receive at the nursing home. This poor information sharing is a significant problem contributing to the adverse events within 45 days of hospital discharge experienced by nearly 40 percent of nursing home residents.

Regenstrief Institute research scientists Kathleen Unroe, M.D., MHA, and Joshua Vest, PhD, MPH, and colleagues from Probari, a start-up company founded by Dr. Unroe and Russell Evans, R.N., MHA, are focusing on improving the quality of nursing home care and have developed and demonstrated the feasibility of a prototype nursing home facing computer application (app) targeting improved information exchange and better care for these high-risk transitions.

The app is tailored to the needs of end-users -- nursing home nurses -- for robust, timely and accessible health record data as a transfer from a hospital to a nursing home takes place. The app enables provision of information to support a seamless transition of care across settings no matter what electronic medical record systems the discharging hospital or the receiving nursing home use and is FHIR® compliant.

Pronounced “fire,” FHIR stands for Fast Healthcare Interoperability Resources and standardizes how healthcare information is exchanged between different computer systems regardless of how it is stored in these systems.

“The challenge we are addressing with the creation of our app is that healthcare is a very diverse landscape of institutions. Hospitals and nursing homes typically run different information systems, so information sharing, which is critically important for optimal care of the nursing home resident, is problematic,” said Dr. Vest, an informatician who has deep interest in both interoperability and social determinants of health. “We built a computer application to leverage existing technology infrastructure to pull information in a systemized, organized and appropriate format to fit workflow needs in nursing homes.

“One of the more revealing findings we learned from our end users was their need for sharing of both clinical and social data, clearly reflecting that we're talking about care for individuals who live in nursing homes,” said Dr. Vest. “So, when we talk about the information moving from a hospital to a nursing home, it really has to encompass not only what they -- nursing home residents -- need for care, but what they also need for daily living and what they need to live their lives ongoing, which was a new kind of twist from this study. And that’s what we built into our app.”

To develop the app, the researchers surveyed nurses and other stakeholders at multiple nursing homes on their information needs and usability requirements.

In 2022 the National Academy of Sciences, Engineering, and Medicine's “The National Imperative to Improve Nursing Home Quality” stated: “Poor communication between nursing homes and hospitals is one of the key barriers to safe and effective care transitions.”

“To provide high quality care for a new or returning resident, nursing homes need to know many things – including blood pressure, pulse, temperature at time of discharge,” said Dr. Unroe, a geriatrician who cares for nursing home patients and has led successful, high impact research studies on avoidable hospitalizations of nursing home residents. “What medicines were administered during the hospital stay and what was the most recent time each was given? Is the patient cognitively impaired?  What was the living situation when the person entered the hospital? Our app transfers that information to the resident’s nursing home care team.

“It matters not only that nurses at nursing homes have access to up-to-date information about what happened during the hospital stay. Access to this information has to be at their fingertips so it is in front of them when and where they need it in order to provide care for that resident,” she added. “It is inefficient and it's dangerous to be distracting the clinical people at the resident’s bedside by expecting the staff member to go into another room and locate often incomplete paperwork or dig into voluminous computer records trying to find basic pieces of information.”

The app performed well and was well received by the potential users surveyed. The next step will be development of the prototype into a fully functioning hospital to nursing home transfer app. The researchers plan to test it in real time with actual transfers to confirm that it will support nursing home nurses to efficiently and safely admit patients as well as to ensure that there is no disruption in the clinical care plan created by the hospital due to transition to a nursing home. 

“Information Needs and Design Requirements for an Application Supporting Safe Transitions Into Skilled Nursing Facilities” is published in The Journal of Post-Acute and Long-Term Care Medicine (JAMDA).

Authors and affiliations:

Joshua R Vest 1, Russell Evans 2, Kellen Drew 2, Kathleen T Unroe 3

1Department of Health Policy and Management, Indiana University Richard M. Fairbanks School of Public Health, Indianapolis, IN, USA; Regenstrief Institute, Inc, Indianapolis, IN, USA.

2Probari, Inc, Indianapolis, IN, USA.

3Probari, Inc, Indianapolis, IN, USA; Division of General Internal Medicine and    Geriatrics, Indiana University School of Medicine, Indianapolis, IN, USA; Regenstrief Institute, Inc, Indianapolis, IN, USA.

This work was supported by a Small Business Innovation Research grant from the National Institutes of Health’s National Institute of Nursing Research.

About Joshua Vest, PhD, MPH
In addition to his roles as Regenstrief research scientist and Fairbanks School of Public Health professor, Joshua Vest, PhD, MPH, is also the director of the Center for Health Policy at the Fairbanks School of Public Health.

About Kathleen T. Unroe, M.D., MHA
In addition to being a research scientist at Regenstrief Institute, Kathleen T. Unroe, M.D., MHA, is an associate professor of medicine at Indiana University School of Medicine and a practicing geriatrician.

About Regenstrief Institute
Founded in 1969 in Indianapolis, the Regenstrief Institute is a local, national and global leader dedicated to a world where better information empowers people to end disease and realize true health. A key research partner to Indiana University, Regenstrief and its research scientists are responsible for a growing number of major healthcare innovations and studies. Examples range from the development of global health information technology standards that enable the use and interoperability of electronic health records to improving patient-physician communications, to creating models of care that inform clinical practice and improve the lives of patients around the globe.

Sam Regenstrief, a nationally successful entrepreneur from Connersville, Indiana, founded the institute with the goal of making healthcare more efficient and accessible for everyone. His vision continues to guide the institute’s research mission.

About the IU Richard M. Fairbanks School of Public Health
Located on the IUPUI and Fort Wayne campuses, the IU Richard M. Fairbanks School of Public Health is committed to advancing the public’s health and well-being through education, innovation, and leadership. The Fairbanks School of Public Health is known for its expertise in biostatistics, epidemiology, cancer research, community health, environmental public health, global health, health policy, and health services administration.

Indiana University School of Medicine
IU School of Medicine is the largest medical school in the U.S. and is annually ranked among the top medical schools in the nation by U.S. News & World Report. The school offers high-quality medical education, access to leading medical research and rich campus life in nine Indiana cities, including rural and urban locations consistently recognized for livability.

About Probari

Probari is an Indiana based small business founded by experts in nursing home care. Probari’s team of nurses specialize in utilizing electronic health records to improve clincal care in nursing homes. www.probarisystems.com

 

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JOURNAL

Journal of the American Medical Directors Association

DOI

10.1016/j.jamda.2023.07.027 

ARTICLE TITLE

Information Needs and Design Requirements for an Application Supporting Safe Transitions into Skilled Nursing Facilities

Endocrine Society recommends bipartisan solutions to Senate HELP hearing on diabetes, obesity

 NEWS RELEASE 14-DEC-2023

THE ENDOCRINE SOCIETY

WASHINGTON—The Endocrine Society commends the Senate Health, Education, Labor, and Pensions (HELP) Committee for calling attention to the issues that are fueling the diabetes epidemic in today’s hearing and urges the Committee to support bipartisan legislation to begin to address the crisis in our country.

More than 38 million Americans have diabetes, and while we have the medications and technologies to treat people living with the disease, access and affordability remain an issue. Obesity, which is a major risk factor for diabetes, affects more than 40 percent of Americans. There are several promising anti-obesity medications available, but supply and cost are major roadblocks, and congressional action is needed to allow Medicare to cover these medications.

“It’s time for Congress to take action and pass legislation to help the millions of people with chronic conditions, including diabetes and obesity, by making their healthcare more affordable and accessible, and by supporting the diabetes research and prevention programs that have been crucial in our fight against this disease,” said the Chair of the Society’s Clinical Affairs Core Committee Joshua Joseph, M.D., M.P.H., of The Ohio State University Wexner Medical Center in Columbus, Ohio. “The Endocrine Society has long advocated to remediate the access and affordability issues that are contributing to the diabetes and obesity epidemics while strengthening the programs that deliver groundbreaking research on diabetes. People with diabetes and obesity deserve access to affordable healthcare that will improve their quality of life.”

The Endocrine Society urges Congress to support the following bipartisan legislation to address the diabetes crisis in our country:

• Reauthorize the Special Diabetes Program (SDP) before January 19—SDP is a bipartisan program created in 1997 that funds critical research being done on type 1 diabetes and type 2 diabetes education and treatment programs for American Indians and Alaska Natives. The Endocrine Society urges Congress to reauthorize SDP through the end of 2025 at $170 million per program, per year, which is a 13% increase in current funding.
• Pass the bipartisan INSULIN Act of 2023—This legislation, introduced by the co-chairs of the Senate Diabetes Caucus, Senators Jeanne Shaheen (D-NH) and Susan Collins (R-ME), includes several policies to make insulin more affordable. It would expand the $35 insulin co-pay cap, which is currently available for people on Medicare, to the private insurance market. The legislation would also ensure that people who rely on insulin are able to share in insulin rebates and discounts, which often go to pharmacy benefit managers and private insurers. Finally, the legislation would promote competition by encouraging the approval of more generic and biosimilar insulins.
• Pass the Treat and Reduce Obesity Act (TROA)—There are groundbreaking Food and Drug Administration-approved medications on the market to treat obesity, and scientific studies have shown these medications are effective. Currently, however, Medicare is prohibited by statute from covering these anti-obesity medications, and congressional action is needed. TROA would allow Medicare to cover anti-obesity medications. We urge the Senate to pass this bipartisan legislation.

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Endocrinologists are at the core of solving the most pressing health problems of our time, from diabetes and obesity to infertility, bone health, and hormone-related cancers. The Endocrine Society is the world’s oldest and largest organization of scientists devoted to hormone research and physicians who care for people with hormone-related conditions.

The Society has more than 18,000 members, including scientists, physicians, educators, nurses and students in 122 countries. To learn more about the Society and the field of endocrinology, visit our site at www.endocrine.org. Follow us on Twitter at @TheEndoSociety and @EndoMedia.

 

Tropical ice cores offer deeper insights into Earth’s temperature record

New study finds these cores may be best indicators of global temperature change

Peer-Reviewed Publication

OHIO STATE UNIVERSITY

SAN FRANCISCO – A new study suggests ice recovered from high tropical mountains can reveal key insights about Earth’s past climate changes.  

Led by scientists at The Ohio State University, the study showed that oxygen-stable isotope records stored in tropical mountain glacier ice cores can be used to provide scientists with a distinct paleoclimate history of the planet’s middle and upper troposphere. By combining ice core proxy records, paleoclimate simulations and modern satellite measurements and comparing the results to those from previous climate models, they found that the temperature in this region of the atmosphere cooled by 7.35 degrees Celsius during the Earth’s glacial period, which for many researchers illuminates new theories about climate dynamics throughout the ages.  

“Typically, you need hundreds of pieces of data to construct a record of global mean temperature,” said Zhengyu Liu, lead author of the study and a professor of geography at The Ohio State University. “It turns out, in that region in the tropics and at that height, you can use just one, and it’s very consistent with many other independent constructions available, which rely primarily on sea surface temperature proxies.” 

Because the ice core, collected from Nevado Huascarán in Peru, was formed in a high-mountain region disconnected from the oceans, samples recovered there are essentially unique “Goldilocks-type” indicators of global mean temperature change. Unlike ice recovered from opposite extremes of the planet such as Greenland or Antarctica, ice from tropical regions provides a happy medium, and holds evidence that is “just right” for measuring Earth’s mean temperature throughout the ages. More importantly, said Liu, their findings show the first solely land-based estimate of global stage cooling, or how much Earth’s temperature decreased during its last glacial period.  

The study, which was published recently in Science Advances, and presented in a poster session today (Dec. 14, 2023) at the annual meeting of the American Geophysical Union, found that surface temperatures during Earth’s glacial cooling stages diminished by as much as 5.9 degrees Celsius.  

“This ice core is like a weather tower quietly recording atmospheric history,” said Liu. According to the study, since the highest tropical ice records are not affected by regional features of the warming environment due to their unique elevation and location, the information these ‘weather towers’ collect is considered to be a more accurate measurement of surface global mean temperature as opposed to records that reflect regional changes.  

It’s for this reason that information gained from even a single tropical ice core could likely be used to enhance scientists’ understanding of a number of different climate elements, including temperature responses during periods of rapid climate change such as the one occurring today as well those likely to occur in the future, said Lonnie Thompson, co-author of the study and professor of earth sciences and a senior research scientist at the Byrd Polar and Climate Research Center. Potent greenhouse gases such as methane, large sources of which come from tropical wetlands, are also preserved in the bubbles in these very high-elevation ice cores where temperatures are very cold and no melting occurs. But by extracting the methane from the ice cores, scientists can construct a history of the changes in its atmospheric concentration. According to Thompson, as methane is a very potent greenhouse gas that can warm the atmosphere at alarming rates, it’s important to have a tropical archive of its past activity. 

“Integrating these tropical records with those from the polar regions provides a more global picture,” he said. “Thus, acquiring these high-elevation tropical climate histories is very important as their data will greatly advance our understanding of Earth’s climate on this planet.” 

The study’s conclusions also shed light on a decades-old scientific debate on how oxygen-stable isotopes in tropical ice cores can be used to interpret climate variations over time. Previous studies have debated whether tropical ice core samples serve as proxies for determining atmospheric changes through either temperature or precipitation processes. This study suggests the tropical ice cores serve as a recorder of air temperature in the mid-upper troposphere across tropics, and more interestingly, as a recorder of global mean surface temperature during Earth’s last glacial period. 

Altogether, the study aims to improve researchers’ understanding of paleoclimatology, as a better understanding of Earth’s climate patterns could help refine both future climate models and extreme weather predictions.  

Yuntao Bao, another co-author of the study and a PhD student in geography at Ohio State, said that their research wouldn’t have been possible without the input of colleagues across many other fields, not just those in the scientific community interested in studying ice cores.  

“The answer to your questions will not come to you the first time, but collaborating with others who have different backgrounds than our own improves our understanding of the world,” said Bao. “With more perspectives, our future work can reach further than it’s ever gone.” 

Other co-authors are Ellen Mosley-Thompson from Ohio State, Clay Tabor from the University of Connecticut, Guang J. Zhang from the University of California, San Diego, Mi Yan from Nanjing Normal University, Marcus Lofverstrom from the University of Arizona, Isabel Montanez from the University of California, Davis, and Jessica Oster from Vanderbilt University. This work was supported by the National Science Foundation. 

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Contact: Zhengyu Liu, Liu.7022@osu.edu

Written by: Tatyana Woodall, Woodall.52@osu.edu

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JOURNAL

Science Advances

DOI

10.1126/sciadv.adi6725 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Tropical mountain ice core δ18O: A Goldilocks indicator for global temperature change

 

Closing the design-to-manufacturing gap for optical devices

A new method enables optical devices that more closely match their design specifications, boosting accuracy and efficiency

Reports and Proceedings

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

Photolithography involves manipulating light to precisely etch features onto a surface, and is commonly used to fabricate computer chips and optical devices like lenses. But tiny deviations during the manufacturing process often cause these devices to fall short of their designers’ intentions.

To help close this design-to-manufacturing gap, researchers from MIT and the Chinese University of Hong Kong used machine learning to build a digital simulator that mimics a specific photolithography manufacturing process. Their technique utilizes real data gathered from the photolithography system, so it can more accurately model how the system would fabricate a design.

The researchers integrate this simulator into a design framework, along with another digital simulator that emulates the performance of the fabricated device in downstream tasks, such as producing images with computational cameras. These connected simulators enable a user to produce an optical device that better matches its design and reaches the best task performance.

This technique could help scientists and engineers create more accurate and efficient optical devices for applications like mobile cameras, augmented reality, medical imaging, entertainment, and telecommunications. And because the pipeline of learning the digital simulator utilizes real-world data, it can be applied to a wide range of photolithography systems.

“This idea sounds simple, but the reasons people haven’t tried this before are that real data can be expensive and there are no precedents for how to effectively coordinate the software and hardware to build a high-fidelity dataset,” says Cheng Zheng, a mechanical engineering graduate student who is co-lead author of an open-access paper describing the work. “We have taken risks and done extensive exploration, for example, developing and trying characterization tools and data-exploration strategies, to determine a working scheme. The result is surprisingly good, showing that real data work much more efficiently and precisely than data generated by simulators composed of analytical equations. Even though it can be expensive and one can feel clueless at the beginning, it is worth doing.” 

Zheng wrote the paper with co-lead author Guangyuan Zhao, a graduate student at the Chinese University of Hong Kong; and her advisor, Peter T. So, a professor of mechanical engineering and biological engineering at MIT. The research will be presented at the SIGGRAPH Asia Conference.

Printing with light

Photolithography involves projecting a pattern of light onto a surface, which causes a chemical reaction that etches features into the substrate. However, the fabricated device ends up with a slightly different pattern because of miniscule deviations in the light’s diffraction and tiny variations in the chemical reaction.

Because photolithography is complex and hard to model, many existing design approaches rely on equations derived from physics. These general equations give some sense of the fabrication process but can’t capture all deviations specific to a photolithography system. This can cause devices to underperform in the real world. 

For their technique, which they call neural lithography, the MIT researchers build their photolithography simulator using physics-based equations as a base, and then incorporate a neural network trained on real, experimental data from a user’s photolithography system. This neural network, a type of machine-learning model loosely based on the human brain, learns to compensate for many of the system’s specific deviations.

The researchers gather data for their method by generating many designs that cover a wide range of feature sizes and shapes, which they fabricate using the photolithography system. They measure the final structures and compare them with design specifications, pairing those data and using them to train a neural network for their digital simulator.

“The performance of learned simulators depends on the data fed in, and data artificially generated from equations can’t cover real-world deviations, which is why it is important to have real-world data,” Zheng says.

Dual simulators

The digital lithography simulator consists of two separate components: an optics model that captures how light is projected on the surface of the device, and a resist model that shows how the photochemical reaction occurs to produce features on the surface.

In a downstream task, they connect this learned photolithography simulator to a physics-based simulator that predicts how the fabricated device will perform on this task, such as how a diffractive lens will diffract the light that strikes it. 

The user specifies the outcomes they want a device to achieve. Then these two simulators work together within a larger framework that shows the user how to make a design that will reach those performance goals. 

“With our simulator, the fabricated object can get the best possible performance on a downstream task, like the computational cameras, a promising technology to make future cameras miniaturized and more powerful. We show that, even if you use post-calibration to try and get a better result, it will still not be as good as having our photolithography model in the loop,” Zhao adds.

They tested this technique by fabricating a holographic element that generates a butterfly image when light shines on it. When compared to devices designed using other techniques, their holographic element produced a near-perfect butterfly that more closely matched the design. They also produced a multilevel diffraction lens which had better image quality than other devices.

In the future, the researchers want to enhance their algorithms to model more complicated devices, and also test the system using consumer cameras. In addition, they want to expand their approach so it can be used with different types of photolithography systems, such as systems that use deep or extreme ultraviolet light.

This research is supported, in part, by the U.S. National Institutes of Health, Fujikura Limited, and the Hong Kong Innovation and Technology Fund.

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Written by Adam Zewe, MIT News

Paper: “Neural Lithography: Close the Design to Manufacturing Gap in Computational Optics with a 'Real2Sim' Learned Photolithography Simulator”

https://arxiv.org/pdf/2309.17343.pdf

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ARTICLE TITLE

“Neural Lithography: Close the Design to Manufacturing Gap in Computational Optics with a 'Real2Sim' Learned Photolithography Simulator”

Parents underestimate the importance of guided play in education, finds US study

US parents are aware of importance of play, but need to learn about the power of playful learning

Peer-Reviewed Publication

FRONTIERS

Child psychologists have long known that play is essential for children’s cognitive development because it boosts their social, physical, and emotional skills. But beginning in the 21st century, specialists repeatedly sounded the alarm that ‘play is under siege’ for US children. Kids were playing less, and – it was feared – with a lesser quality.

But are today’s parents sufficiently aware of the importance of letting their children play? Yes, found a team of researchers who tested this through a survey of the opinions of 1,172 US parents. Their results showed that today’s parents understand how important play is for children’s well-being. However, they also showed that work needs to be done to educate parents about the value of playful learning (or ‘guided play’) for learning goals in reading and math.

“Here we show that US parents understand that play can be more powerful for learning than direct instruction,” says first author Charlotte Wright, a senior research associate at Temple University College of Liberal Arts, Philadelphia.

“Until recently, people generally considered play to be the opposite of work and learning. What we see in our study is that this separation no longer exists in the eyes of parents: a positive development.”

Parents rate free play the most

Parents were interviewed aged between 18 and 75, with children aged between two and 12. Parents were White (68.9%), Hispanic (14.4%), Black (10.3%), Asian (3.4%), mixed race (2.6%), or American Indian or Native Alaskan (0.4%). Household income ranged from less than $25,000 to more than $100,000. Their level of education ranged from lacking a high school diploma (4.4%) to having a postgraduate degree (11.9%)

The results showed that parents tended to rate free play as best for learning, followed by guided play, games, and direct instruction, respectively. This held true, both when these types of education were explicitly named, or when they were only implied in given scenarios.

The higher the parent’s level of education, and the higher their household income, the more they tended to rate free play as the most effective method for learning. Likewise, parents of girls were more likely to rate free play as most educational than parents of boys. In contrast, Black or Hispanic parents were more likely to rate direct instruction higher than forms of play.

An example of guided play

The current research consensus is that guided play is more effective than free play for children to learn skills such as mathematics, language and literacy, and the spatial awareness necessary for STEM skills.

Guided play, possible in the home and in the classroom, differs from free play in being initiated by the adult, while letting the child drive her learning towards a specific goal. For example, learning in Montessori classrooms and children’s museums is always initiated by an adult who reflects on learning goals. But children themselves drive the exploration within such guided learning environments – giving them choice and voice.

The authors gave an example scenario of guided play: “Raouf’s father, Ola, says to Raouf, ‘I wonder if we can build a tall tower with these blocks.’ Ola follows Raouf’s lead as Raouf tries to build the tower, asking questions to support him, when necessary (eg, ‘Hmmm, our tower keeps falling when we put the blue block on the bottom! What is another block we could try?’).”

Adults thus become the support team, but not the directors, of guided play.

Wright et al. concluded that “many US parents hold perceptions that do not align completely with evidence-based research, such as attributing more learning value to free play […]  compared to guided play.”

The results also showed that when parents were better informed about current theory on child cognitive development (as measured by questions from the Knowledge of Infant Development Inventory (KIDI) questionnaire), they tended to value guided play more.

The concept of different kinds of play, such as guided vs free play, was only recently introduced in research and may not yet be evident to the public. Guided play also requires that parents engage with their children during a play experience, which might lead them to undervalue guided play in favor of free play.

Importance of educating parents

“While free play is crucial for children's well-being, recent research emphasizes that guided play is a more effective approach to support children’s learning in reading, STEM, and learning-to-learn skills like attention, memory, and flexible thinking,” said Wright.

Senior author Dr Kathy Hirsh-Pasek, a professor at the same institute, said: “We need to help refine parents’ knowledge about the importance of play so that they can create guided play opportunities in everyday experiences like doing laundry, taking a walk in the park, or playing with a puzzle. As parents come to see these as ‘learning’ moments in everyday play, their children will thrive, while they will have more fun being parents.”

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JOURNAL

Frontiers in Developmental Psychology

DOI

10.3389/fdpys.2023.1267169 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

People

ARTICLE TITLE

U.S. Parents' Attitudes Towards Playful Learning

ARTICLE PUBLICATION DATE

15-Dec-2023