These teleconnections between the tropical Pacific and far-flung areas are reported in a Cornell University-led computer-model study published in Nature Geoscience.

While other computer models have projected similar precipitation increases generated by a warming Southern Ocean, major uncertainties and a wide range of predictions exist between models.

The new study serves to reduce those uncertainties, which could improve predictions of global mean temperatures and regional precipitation.

“We needed to find the cause of those uncertainties,” said Hanjun Kim, the study’s co-corresponding author and a postdoctoral associate working with co-authors Flavio Lehner and Angeline Pendergrass, both assistant professors of atmospheric sciences at Cornell. Sarah Kang, professor in the Max Planck Institute for Meteorology in Hamburg, Germany, is the paper’s other corresponding author.

“I found that low-altitude cloud feedbacks over the Southern Hemisphere can be one cause of those uncertainties in remote Northern Hemisphere regional precipitation,” Kim said. “If we try to reduce the uncertainty of Southern Hemisphere cloud feedbacks, then we can also improve the prediction of global mean temperatures.”

The Southern Ocean has a higher capacity for absorbing heat than other bodies of water due to a strong upwelling of deep cold water, but eventually the water will warm and gradually release heat. When this happens, that heat is distributed, creating teleconnections, which are predicted to increase precipitation in East Asia during summers and in the Western U.S. during winters. Such teleconnections are very similar to how El Niño affects weather patterns.

The model predicted that due to the ocean’s slow release of heat, the new precipitation patterns could persist for up to 150 years, regardless of efforts to reduce greenhouse gases.

“We can occasionally see these processes today, which allows us to study them,” Lehner said, “but we expect in the future for these processes to switch from being an occasional occurrence to being a more permanent state of the system.”

Kim found that low-lying clouds over the Southern Ocean act as a key regulator affecting sea-surface temperatures. Accounting for these cloud feedbacks in climate models help explain the uncertainties and variations from one model to another, according to the study.

There are few observational facilities in Antarctica to provide data on cloud feedbacks in the Southern Ocean, so increasing those would in turn improve predictions, Kim said.

HIV-diagnostic technology traditionally relied on the detection of HIV-specific antibodies that form several weeks after infection. This has limited their use in early detection, complicating patient care and HIV prevention efforts. Newer tests that detect both HIV antibodies and the p24 antigen (an earlier marker of HIV infection) are now the gold standard for diagnosis, but require clinical labs to run results, contributing to longer processing times, higher costs and the need for multiple patient visits.

The technology described in a study published today (April 2) in the journal Biosensors and Bioelectronics uses a nanomechanical platform and tiny cantilevers to detect multiple HIV antigens at high sensitivity in a matter of minutes. These silicon cantilevers are cheap and easy to mass produce and can be readily equipped with a digital readout. Built into a solar-powered device, this technology could be taken to hard-to-reach parts of the world where early detection remains a challenge to deliver fast interventions to vulnerable populations without waiting for a lab.

“We hope this technology will lead to the development of new point-of-care diagnostics for HIV to improve patient health and help bring an end to this epidemic,” said Northwestern virologist and co-author of the study, Judd F. Hultquist.

After proving its efficacy in testing for both the SARS-CoV-2 virus that causes COVID-19, and now HIV, the team is confident that the biosensor will continue to prove effective when testing for additional diseases. A potential next target, they say, could be measles, another infection in desperate need of point-of-care interventions as cases rise across multiple U.S. states.

The team was led by co-corresponding authors Vinayak Dravid, a materials engineer, Hultquist, a virologist, and co-author Gajendra Shekhawat, a micro- and nanofabrication expert in the Dravid Lab.

“When we first developed the microcantilever technology 20 years ago, I realized that this technology is so generally applicable,” Dravid said. “It is a very powerful tool that depends on three basic things: sensitivity, antigen-antibody affinity and specificity. This is where HIV comes in, because HIV is so pernicious that it mutates so there is no unique antibody. We had to figure out how to overcome that challenge.”

Beginning with pure samples of the p24 antigen, the team applied layers of antibodies onto each “finger” of the gold-coated microcantilever to measure how strongly p24 bonded to the surface, which would cause the cantilever to bend a measurable and quantifiable amount.

After this proof-of-concept, the team introduced human blood samples, which are much more complex than purified samples. The sensor continued to bend only in samples where p24 was present, demonstrating high specificity.

Finally, the scientists added two antibodies to different “fingers” of the microcantilever to more broadly cover all HIV subtypes. Even in very low concentrations, the test accurately responded when antigens specific to HIV were introduced.

“To account for HIV’s genetic diversity, we functionalized the test for HIV using broadly cross-reactive antibodies (ANT-152 and C65690M),” Shekhawat said. “This allowed accurate detection across diverse HIV-1 subtypes, ensuring reliability in global settings.”

To streamline diagnostics and enable immediate medical care, the team envisions developing a point-of-care test simultaneously detecting HIV, hepatitis B and hepatitis C antigens, acknowledging the higher prevalence of hepatitis co-infections in people living with HIV that can lead to severe liver complications if left untreated.

Dravid is the Abraham Harris Professor of Materials Science and Engineering at the McCormick School of Engineering and a faculty affiliate of the Paula M. Trienens Institute for Sustainability and Energy. He is also the founding director of the Northwestern University Atomic and Nanoscale Characterization (NUANCE) Center as well as the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource, and also serves as the associate director for global programs at the International Institute of Nanotechnology.

Hultquist is an assistant professor of medicine at Northwestern University Feinberg School of Medicine and serves as the associate director for the Center for Pathogen Genomics and Microbial Evolution in the Havey Institute for Global Health. He specializes in translational research of infectious diseases and host-pathogen interactions.

Shekhawat is a research professor of materials science and engineering at McCormick, researching semiconductor microfabrication, integration of sensors with synthetic biology and biomaterials and nanoscale characterization.

The research was supported by an award from the National Institutes of Health-funded Third Coast Center for AIDS Research (P30AI117943), as well as through NIH funding for the HIV Accessory & Regulatory Complexes Center (U54 AI170792) and NIH funding for HIV research (R01AI176599, R01AI167778, R01AI150455, R01AI165236, R01AI150998, R21 AI174864, and R56AI174877).

Vinayak Dravid, Gajendra Shekhawat, Judd Hultquist and Northwestern have financial interests (equities, royalties) in the reported research.

A dissection in the artery wall is most often caused by trauma due to motor vehicle accidents but can also occur with smaller injuries. Heavy lifting has also been shown to cause dissection in some people.

“Cervical artery dissection is an important cause of stroke, especially in people under 50, so it is crucial to detect it right away,” said Shadi Yaghi, MD, of Brown University in Providence, Rhode Island. “Strokes that are not fatal can lead to long-term disability, poor mental health and reduced quality of life. Our research found a dramatic increase in the number of hospitalizations for cervical artery dissection with rates rising steadily year over year.”

For the study, researchers reviewed 15 years of U.S. health data to identify 125,102 people hospitalized for cervical artery dissection. Participants had an average age of 51, and just over half had a stroke at the same time as dissection. Of all participants, 65% were white, 10% were Black, 8% were Hispanic, 3% were Asian or Pacific Islander, and 14% were of other racial groups.

Researchers compared the number of hospitalizations to U.S. Census data to determine the annual rate of cervical artery dissections. They then calculated the average annual percentage change in those rates.

Researchers found the number of dissections increased from 11 cases per one million people in 2005 to 46 cases per one million people in 2019, with an average annual increase of 10%. Results were similar for both female and male participants.

The average annual increase for Hispanic participants was 16%, for Black participants it was 13%, Asian participants, 12% and white participants, 8%.

Researchers also found a greater average annual increase among people 65 and older at 12% compared to 8% for people under 65.

“Possible reasons for this nearly five-fold increase over 15 years include greater awareness of cervical artery dissection by health care professionals, better access to imaging to help identify it and an overall increase in this condition for which a cause has yet to be determined,” said Yaghi. “Given the rising incidence of cervical artery dissection, our study underscores the importance of finding prevention strategies as well as new treatments to reduce the risk of stroke.”

A limitation of the study was that the hospital admission data does not include undiagnosed or untreated cases, so the number of cases may be even higher.