The article reveals that personal care products can significantly suppress the human oxidation field, which is generated by people’s presence indoors. This field changes the indoor air chemistry around us, affecting our intake of chemicals and impacting human health.

Researchers from the Max Planck Institute for Chemistry conducted a study in 2022 that found high levels of OH radicals can be generated indoors due to the presence of people and ozone. A follow-up study showed that commonly used personal care products substantially suppress a person’s production of OH radicals, with implications for indoor chemistry, air quality, and human health.

The study involved an international research team, including scientists from the University of California (Irvine, USA) and the Pennsylvania State University. They developed a state-of-the-art chemical model to simulate concentrations of chemical compounds near humans in the indoor environment.

The researchers examined how body lotion and perfume affect the human oxidation field. When applied to the skin, they found that both products suppressed the production of OH radicals, with the primary component of perfume (ethanol) reacting with OH radicals. Body lotion also contributed to suppressing the human oxidation field by reacting with ozone on the skin.

The study suggests that fragrances impact the OH reactivity and concentration over shorter time periods, whereas lotions show more persistent effects consistent with the rate of emissions of organic compounds from these personal care products.

Implications for indoor chemistry include the suppression of the personal human oxidation field when applying a fragrance indoors. Lotions are expected to suppress the human oxidation field due to dilution of skin oil constituents and reduced interaction between O3 and the skin, as well as the presence of preservatives acting as antimicrobial agents.

The study was part of the ICHEAR project (Indoor Chemical Human Emissions and Reactivity Project), which brought together international scientists from Denmark, USA, and Germany. The modeling was part of the MOCCIE project based in University of California Irvine and the Pennsylvania State University, funded by grants from the A. P. Sloan foundation.

In conclusion, personal care products can have a significant impact on indoor air chemistry, suppressing the human oxidation field that affects our intake of chemicals and human health. As we spend up to 90% of our time indoors, it is essential to be aware of this phenomenon and consider the potential implications for our well-being.

The experiments were conducted in a climate-controlled chamber at the Technical University of Denmark (DTU) in Copenhagen, where four test subjects stayed under standardized conditions. Ozone was added to the chamber air inflow, and the team determined the OH concentrations indirectly by quantifying individual OH sources and overall loss rates of OH. By combining air measurements with model simulations, they calculated the effect of lotion and fragrance on the human oxidation field.

The findings have implications for indoor chemistry, highlighting the need for further research into the properties and effects of chemical compounds in our breathing zone.

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Microbes on Our Skin: The Hidden Heroes Against Sun Damage

Researchers have made a groundbreaking discovery about the skin microbiome, revealing that certain bacteria can protect us from the bad effects of sunlight by metabolizing cis-urocanic acid using an enzyme called urocanase. This enables our skin to fine-tune its response to UV radiation.

The study, published in the Journal of Investigative Dermatology, demonstrates the ability of the skin microbiome to remodel host immune functions. Lead investigator VijayKumar Patra, PhD, explains that many internal and external factors influence the composition of the skin microbiome, including individual parameters such as race, gender, age, hormone levels, diet, and hygiene.

Researchers used a combination of microbiome sequencing, immunological assays, in vitro cultures, and gnotobiotic mouse models to study how skin bacteria respond to UVB radiation. They discovered that certain skin bacteria specifically metabolize cis-urocanic acid, a photoproduct of a major UV-absorbing chromophore of the stratum corneum, using an enzyme called urocanase.

Co-investigator Marc Vocanson, PhD, notes that this is the first time a direct metabolic link between UV radiation, a host-derived molecule, and bacterial behavior affecting immune function has been demonstrated. As interest grows in microbiome research and personalized medicine, understanding these microbe-host interactions could reshape the way we think about sun protection, immune diseases, skin cancer, or even treatments like phototherapy.

Co-investigator Peter Wolf, MD, concludes that these findings open the door to microbiome-aware sun protection, where we not only protect the skin from UV radiation but also consider how resident microbes can alter the immune landscape after exposure. In the future, topical treatments that modulate microbial metabolism could be used to minimize, maintain, or enhance UV-induced immunosuppression when clinically beneficial.

Noted expert Anna Di Nardo, MD, PhD, comments on the findings, saying that this pivotal study shows that microbial communities are not passive victims of environmental stress but dynamic regulators of immune responses. This newly uncovered role of microbial metabolism in modulating UV tolerance reshapes our understanding of the skin barrier – not just as a structural shield but as a metabolically active, microbially regulated interface.

With increasing concerns about UV exposure, skin aging, and cancer, a deeper understanding of this axis offers promising avenues for therapy and prevention.

Researchers at the University of Arizona have made a groundbreaking discovery in the field of eye-tracking technology. By integrating a powerful 3D imaging technique called deflectometry with advanced computation, they have developed a method that can significantly improve the accuracy of gaze direction estimation. This innovative approach has the potential to revolutionize applications in virtual reality, entertainment, scientific research, medical and behavioral sciences, automotive driving assistance, and industrial engineering.

The new technology uses a screen displaying known structured light patterns as the illumination source, allowing researchers to obtain accurate and dense 3D surface data from both the cornea and the white area around the pupil. By analyzing the deformation of the displayed patterns as they reflect off the eye surface, scientists can accurately predict the gaze direction.

In experiments with human participants and a realistic artificial eye model, the team measured the study subjects’ viewing direction and was able to track their gaze direction with accuracies between 0.46 and 0.97 degrees. When tested on the artificial eye model, the error was around just 0.1 degrees.

This technology has the potential to seamlessly integrate with virtual reality and augmented reality systems by using a fixed embedded pattern in the headset frame or the visual content of the headset itself as the pattern that is reflected from the eye surface. This can significantly reduce system complexity, allowing for more accurate and precise tracking of user interactions.

The researchers believe that their new method will enable a new wave of next-generation eye-tracking technology, including applications such as neuroscience research and psychology. With further engineering refinements and algorithmic optimizations, they aim to push the limits of eye tracking beyond what has been previously achieved using techniques fit for real-world application settings. Their goal is to close in on the 0.1-degree accuracy levels obtained with the model eye experiments.

This innovative technology has the potential to improve our understanding of human behavior, enhance user experiences in virtual reality and augmented reality applications, and even aid in the diagnosis and correction of specific eye disorders. The researchers’ plans for commercialization through Tech Launch Arizona pave the way for a new era of robust and accurate eye-tracking, with exciting possibilities for future development and implementation.