In one such phenomenon, called quantum entanglement, pairs of photons become interconnected in such a way that the state of one photon instantly changes to match the state of its paired photon, no matter how far apart they are.

Nearly 80 years ago, Albert Einstein referred to this phenomenon as “spooky action at a distance.” Today, entanglement is the subject of research programs across the world — and it’s becoming a favored way to implement the most fundamental form of quantum information, the qubit.

Currently, the most efficient way to create photon pairs requires sending lightwaves through a crystal large enough to see without a microscope. In a paper published today in Nature Photonics, a team led by Columbia Engineering researchers and collaborators, describe a new method for creating these photon pairs that achieves higher performance on a much smaller device using less energy. P. James Schuck, associate professor of mechanical engineering at Columbia Engineering, helped lead the research team.

These findings represent a significant step forward in the field of nonlinear optics, which is concerned with using technologies to change the properties of light for applications including lasers, telecommunications, and laboratory equipment.

“This work represents the embodiment of the long-sought goal of bridging macroscopic and microscopic nonlinear and quantum optics,” says Schuck, who co-directs Columbia’s MS in Quantum Science and Technology. “It provides the foundation for scalable, highly efficient on-chip integrable devices such as tunable microscopic entangled-photon-pair generators.”

How it works

Measuring just 3.4 micrometers thick, the new device points to a future where this important component of many quantum systems can fit onto a silicon chip. This change would enable significant gains in the energy efficiency and overall technical capabilities of quantum devices.

To create the device, the researchers used thin crystals of a so-called van der Waals semiconducting transition metal called molybdenum disulfide. Then they layered six of these crystal pieces into a stack, with each piece rotated 180 degrees relative to the crystal slabs above and below. As light travels through this stack, a phenomenon called quasi-phase-matching manipulates properties of the light, enabling the creation of paired photons.

This paper represents the first time that quasi-phase-matching in any van der Waals material has been used to generate photon pairs at wavelengths that are useful for telecommunications. The technique is significantly more efficient than previous methods and far less prone to error.

“We believe this breakthrough will establish van der Waals materials as the core of next-generation nonlinear and quantum photonic architectures, with them being ideal candidates for enabling all future on-chip technologies and replacing current bulk and periodically poled crystals,” Schuck says.

“These innovations will have an immediate impact in diverse areas including satellite-based distribution and mobile phone quantum communication.”

How it happened

Schuck and his team built on their previous work to develop the new device. In 2022, the group demonstrated that materials like molybdenum disulfide possess useful properties for nonlinear optics — but performance was limited by the tendency of light waves to interfere with one another while traveling through this material.

The team turned to a technique called periodic poling to counteract this problem, which is known as phase matching. By alternating the direction of the slabs in the stack, the device manipulates light in a way that enables photon pair generation at miniscule length scales.

“Once we understood how amazing this material was, we knew we had to pursue the periodic poling, which could allow for the highly efficient generation of photon pairs,” Schuck says.

This work occurred within Programmable Quantum Materials, a Department of Energy energy frontier research center (EFRC) at Columbia, as part of a larger effort to understand and exploit quantum materials. This work was possible due to contributions from the Baso, Delor, and Dean labs. Postdoctoral researcher Chiara Trovatello led the effort.

“Many of the materials in our day-to-day lives are flammable, and offering a solution to protect from fire benignly is difficult,” said Maya D. Montemayor, a graduate student in the Department of Chemistry at Texas A&M and the publication’s lead author. “This technology can be optimized to quickly, easily, and safely flame retard many flammable materials, offering vast protection in everyday life, saving money and lives of the general population.”

Current studies developing flame retardant coatings deposited via polyelectrolyte complexation require two or more steps, increasing the time and cost to coat a material effectively.

In contrast, this study recently published in ACS Applied Polymer Materials hopes to achieve the same results using only one step. The researchers address this issue by incorporating a volatile base, a molecule that evaporates under ambient conditions. Using ammonia as the volatile base, the base evaporates to reduce the pH and induce complexation (a chemical reaction that forms a stable complex) on the cotton’s surface. Until now, this technique has been proposed but never used to prepare a flame-retardant treatment.

This research can be utilized to deposit polyelectrolyte-based flame-retardant coatings in a scalable and efficient manner. Other positive attributes of the technology include that it is aqueous (water-based) and non-toxic, unlike many other flame-retardant treatments.

The researchers will continue evaluating this technology in partnership with companies in hopes of using their findings to protect wood, fabric, foam and other textiles.

“This cutting-edge research offers Texas A&M recognition as one of the leaders of this technology and the opportunity for further development with external companies,” said Dr. Jaime Grunlan, Leland T. Jordan ’29 Chair Professor in the J. Mike Walker ’66 Department of Mechanical Engineering at Texas A&M. “The scope of this research positively impacts our community by improving our safety in an environmentally benign manner. TEES is licensing this and similar technologies to companies for various applications.”

Other contributors to the findings include Texas A&M graduate students Danixa Rodriguez-Melendez, Dallin L. Smith, Natalie A. Vest and Bethany Palen, and Texas A&M undergraduate students Edward Chang and Alexandra V. Moran.

Funding for this research is administered by the Texas A&M Engineering Experiment Station (TEES), the official research agency for Texas A&M Engineering.

The study, led by Luiz Bertassoni, D.D.S., Ph.D., founding director of the Knight Cancer Precision Biofabrication Hub and a professor at the OHSU Knight Cancer Institute and the OHSU School of Dentistry, shows that perivascular cells sense changes in nearby tissues and send signals that disrupt blood vessel function, worsening disease progression.

Nearly a decade ago, Bertassoni and his team developed a method to 3D print blood vessels in the lab — a breakthrough recognized as one of the top scientific discoveries of the year by Discover magazine. Since then, they’ve focused on engineering blood vessels that better mimic those in the human body to study more complex diseases.

“Historically, endothelial cells lining blood vessels have been considered the main contributors of vascular disease,” Bertassoni said. “Our findings represent a paradigm shift, showing how perivascular cells, instead, act as important sentinels. They detect changes in tissues and coordinating vascular responses. This opens the door to entirely new treatment strategies.”

Cristiane Miranda Franca, D.D.S., Ph.D., the study’s lead author, is an assistant professor in the OHSU School of Dentistry and holds appointments with the OHSU Knight Cancer Precision Biofabrication Hub and Knight Cancer Institute’s Cancer Early Detection Advanced Research Center, or CEDAR.

“The applications of this research are wide,” she said. “We’ve shown for the first time how perivascular cells trigger inflammation and signal blood vessel changes when surrounding tissues are altered.”

The study used an innovative “blood vessel on-a-chip” model developed by Christopher Chen, M.D., Ph.D., and his team from Boston University and the Wyss Institute at Harvard, who are collaborators on this project. By replicating conditions like tissue stiffening and scarring — common in aging, chronic diseases and cancer — the researchers discovered that perivascular cells drive blood vessel leakage and distortion, worsening inflammation and disease.

Learn more: OHSU Knight Cancer Institute offers the latest treatments, technologies, hundreds of research studies and clinical trials

“When we removed perivascular cells, blood vessels essentially failed to respond to tissue changes,” Franca said.

The findings shed light on the relationship between the extracellular matrix, blood vessel function and disease progression. Perivascular cells could become targets for therapies aimed at restoring normal vascular function and reducing the progression of various diseases such as fibrosis, diabetes and cancer.

Importantly, the research also holds promise for cancer prevention and early intervention. Early detection and treatment of changes in these cells could help stop tumors before they grow.

“If we intervene early, we might prevent precancerous lesions from advancing to full-blown cancer,” Bertassoni said. “This could revolutionize how we approach cancer prevention and treatment.”

In addition to Bertassoni and Franca, OHSU co-authors include Maria Elisa Lima Verde, Ph.D., Alice Correa Silva-Sousa, D.D.S., Ph.D., Amin Mansoorifar, Ph.D., Avathamsa Athirasala, M.S., Ramesh Subbiah, Ph.D., Anthony Tahayeri, B.S., Mauricio Sousa, D.D.S., M.S., Ph.D., May Anny Fraga, D.D.S., M.S., Rahul Visalakshan, Ph.D., Aaron Doe, M.S., Keith Beadle, B.S., and McKenna Finley, B.A. Co-authors also include Emilios Dimitriadis, Ph.D., with the National Institute of Biomedical Imaging and Bioengineering; Jennifer Bays, Ph.D., and Marina Uroz, Ph.D., with Boston University; and Kenneth Yamada, M.D., Ph.D., with the National Institute of Dental and Craniofacial Research of the National Institutes of Health.

People who have limited access to air conditioning may be at higher risk of seeking emergency care for health problems following exposure to wildfire smoke, according to a new study led by Boston University School of Public Health (BUSPH).

Posted online ahead of publication in the journal Environmental Research: Health, the study found that exposure to fine particle matter (PM2.5) from wildfire smoke in California is associated with higher rates of emergency department visits for all causes, non-accidental causes, and respiratory disease. This risk varied by age and race, but was especially high for individuals who lived in areas with lower availability of air conditioning.

The findings come at a critical time, as firefighters in Southern California continue to battle multiple wildfires that have been blazing in and around Los Angeles County since Tuesday, January 7 — including the Palisades fire, which is likely the largest and most destructive wildfire in the county’s history. Health experts are urging residents who are not under evacuation orders and can safely remain in their homes to turn on air conditioners and/or air purifiers if they have access to these devices.

Despite this guidance — and the growing threat of more frequent and intense wildfires due to worsening climate change — very little research has examined how the health effects of wildfire smoke exposure may differ based on individuals’ access to air conditioning. Understanding this relationship can inform policies and interventions that mitigate barriers to air conditioners and protect vulnerable populations from the consequences of inhaling PM2.5 and other harmful pollutants from this smoke, which can permeate the air from hundreds or thousands of miles away.

“Depending on the type of system and filter used, air conditioning may modify the impact of smoke exposure on human health,” says study lead and corresponding author Dr. Jennifer Stowell, research scientist in climate and health at BUSPH, noting that the analysis only addressed the likelihood of access to air conditioning, rather than air conditioning types or actual usage. “Studies like these will become more and more relevant as wildfire exposure increases. California is, perhaps, the best example of this in the US, with bigger fires and longer fire seasons. An important next step will be to identify ways to better characterize access to air conditioning.”

For the study, Dr. Stowell and colleagues from BUSPH, Boston University College of Arts & Sciences (CAS), and the Health Effects Institute utilized a nationwide dataset of healthcare claims to assess more than 50,000 emergency department visits during the 2012-2019 California wildfire seasons, which occurred from May to November each year. They quantified the adverse health effects from PM2.5 exposure among all study participants, as well as subgroups of participants.

Consistent with prior research, wildfire smoke exposure was most strongly associated with emergency department visits for respiratory issues, but not cardiovascular-related complications. These visits were generally higher among children under 10 years old, adults between 20-74 years old, and among the Black population, although also elevated among White, Hispanic, and Asian/Pacific Islander populations.

People living in areas with lower availability of air conditioning had a 22-percent greater risk of visiting the emergency department for respiratory conditions associated with wildfire smoke exposure. Greater insight into air conditioning use as a pollutant-filtering tool and the barriers that certain populations face in accessing these cooling systems is critical, as wildfires are expected to occur more regularly in the Wildland-Urban Interface (WUI) — areas where human activity is in close contact with sources of dry fuel. This is exactly what is happening now in LA County, Dr. Stowell says, as the fires destroy thousands of homes and businesses near vegetation.

“WUI fires are particularly concerning due to the burning of human-made structures and the additional toxic chemicals and particulates that can be found in their smoke plume,” says Dr. Stowell. “The current fires in LA are out-of-season fires driven by severe Santa Ana winds coming from the mountains. As climate change continues, the temperature differentials between land and sea will grow and, potentially, drive stronger and stronger late-season or out-of-season wind events.”

So how may residential air conditioners help dispel PM2.5 from homes? The filters in these cooling systems can remove particulate matter, although certain filters are more effective at filtering particulate matter than others. “HEPA filters can remove the majority of particles greater than 0.3 µm, but they are significantly more expensive than fiberglass air filters, which only remove larger particles and may allow high amounts of fine particulate matter to penetrate indoors,” Dr. Stowell says. “Generic pleated air filters are also fairly efficient at filtering out most particulate matter.”

Air conditioning systems with a Minimum Efficiency Reporting Value (MERV) rating of seven or higher are thought to be the most efficient at removing particulate matter from outdoor air, but are also more expensive.

The study findings indicate a need for stronger policy measures that can reduce the health risks associated with wildfire smoke exposure.

“Many homeowners do not understand the differences between MERV ratings and how these might impact your health,” Dr. Stowell says. “Policymakers should consider delivering better information to the public — such as the types and ratings of filters that perform better — especially for those who reside in smoke-prone regions.”

Given that marginalized populations appear to be disproportionately burdened by the health effects of wildfire smoke exposure, economic assistance should also be considered, she says, particularly for low-income populations residing in smoke-prone regions. “Considering the current fires in CA, local and state governments should heighten their responses to these events and develop plans and policies to reduce exposure before the fires occur,” Dr. Stowell says.

The study’s senior author is Dr. Gregory Wellenius, professor of environmental health and director of the Center for Climate and Health at BUSPH. The study was coauthored by Dr. Ian Sue Wing, professor of earth and environment at CAS; Dr. Yasmin Romitti, staff scientist at the Health Effects Institute, and Dr. Patrick Kinney, Beverly Brown Professor of Urban Health at BUSPH.

UC Riverside scientists have now discovered a chemical that plants produce when they’re stressed prevents biofilm from forming. The breakthrough offers potential advances in healthcare as well as preventing equipment corrosion in industrial settings.

“In simple terms, biofilms are communities of microorganisms, like bacteria or fungi, that stick together and form a protective layer on surfaces,” said Katayoon Dehesh, distinguished professor of molecular biochemistry at UCR, and corresponding author of a study about the discovery.

“You’ve probably seen them as the slimy layer on river rocks or the plaque on your teeth. While they’re a natural part of many ecosystems, biofilms can cause big problems.”

The study, published in the journal Nature Communications, highlights the importance of a particular metabolite, which is a molecule produced during life-sustaining chemical reactions inside plants, as well as bacteria and even some parasites, like the one that causes malaria.

In plants, this metabolite, MEcPP, plays a critical role not only in producing essential compounds but also in stress signaling. For example, when a plant is damaged in some way and too much oxygen enters its cells, it accumulates MEcPP. This molecule then triggers protective responses within the plant. The researchers discovered that this same molecule has a surprising effect on bacteria like E. coli: it disrupts biofilm development by interfering with its ability to attach to surfaces.

In medical settings, biofilms grow on devices like catheters, stents, or implants, making infections harder to treat because the microbes in biofilms are highly resistant to antibiotics. In industrial contexts, they clog pipes, contaminate food processing equipment, and cause corrosion.

“By preventing the early stages of biofilm development, this molecule offers real potential to improve outcomes in any industries reliant on clean surfaces,” Dehesh said.

Bacteria rely on hair-like structures called fimbriae to anchor themselves to surfaces, a critical step in biofilm initiation. Fimbriae help bacteria latch onto medical implants, pipes, or even teeth, where they secrete a protective matrix that shields them from antibiotics and cleaning agents. Without fimbriae, biofilm formation cannot begin.

“Biofilms are like fortresses for bacteria,” said Jingzhe Guo, UCR project scientist and first author of the paper. “By disrupting the initial phase of attachment, MEcPP essentially disarms the bacteria’s ability to establish these fortresses.”

Through genetic screenings of more than 9,000 bacterial mutants, the research team identified a key gene called fimE, which acts as an “off switch” for fimbriae production. MEcPP enhances the activity of this gene and increases the expression of fimE. This, in turn, prevents the bacteria from producing fimbriae and forming biofilms.

“Our discovery could inspire biofilm prevention strategies across a wide range of industries,” Guo said. “From cleaner water systems to better dental care products, the possibilities are immense.”

Biofilms are not only a medical concern but also a costly problem in industrial settings. They contribute to clogged pipelines, corroded machinery, and contamination in food processing facilities. Traditional methods for managing biofilms often rely on harsh chemicals or expensive treatments, which can be harmful to the environment or ineffective over time as bacteria adapt.

“This study is a testament to the unexpected connections between plant biology and microbiology,” Guo said. “It’s thrilling to think a molecule that plants use to signal stress might one day help humans combat bacterial threats.”