Volatile chemical products (VCPs) are increasingly recognized as significant sources of volatile organic compounds (VOCs) in urban atmospheres, potentially serving as key precursors for secondary organic aerosol (SOA) formation. This study investigates the formation and physicochemical transformations of VCP-derived SOA, produced through ozonolysis of VOCs evaporated from a representative room deodorant air freshener, focusing on the effects of aerosol evaporation on its molecular composition, light absorption properties, and reactive oxygen species (ROS) generation. Following aerosol evaporation, solutes become concentrated, accelerating reactions within the aerosol matrix that lead to a 42% reduction in peroxide content and noticeable browning of the SOA. This process occurs most effectively at moderate relative humidity (∼40%), reaching a maximum solute concentration before aerosol solidification. Molecular characterization reveals that evaporating VCP-derived SOA produces highly conjugated nitrogen-containing products from interactions between existing or transformed carbonyl compounds and reduced nitrogen species, likely acting as chromophores responsible for the observed brownish coloration. Additionally, the reactivity of VCP-derived SOA was elucidated through heterogeneous oxidation of sulfur dioxide (SO2), which revealed enhanced photosensitized sulfate production upon drying. Direct measurements of ROS, including singlet oxygen (1O2), superoxide (O2•-), and hydroxyl radicals (•OH), showed higher abundances in dried versus undried SOA samples under light exposure. Our findings underscore that drying significantly alters the physicochemical properties of VCP-derived SOA, impacting their roles in atmospheric chemistry and radiative balance.

Photodynamic therapy (PDT) has been a topic of interest since the first report in 1900 but has yet to become a \'mainstream\' treatment protocol in the medical field. There are clear indications for which PDT might be the \'method of choice\', but it is unlikely that there will be protocols for the treatment of systemic disease. This report discusses recent developments for promoting PDT efficacy, in the context of what is already known. Factors that can limit the scope of these applications are also indicated. Among the more interesting of these developments is the use of formulation techniques to target specific organelles for photodamage. This can enhance responses to PDT and circumvent situations where an impaired death pathway interferes with PDT efficacy.

Carbon-semiconductor hybrid quantum dots are classical carbon dots with core carbon nanoparticles doped with a selected nanoscale semiconductor. Specifically, on those with the nanoscale TiO2 doping, denoted as CTiO2-Dots, their synthesis and thorough characterization were reported previously. In this work, the CTiO2-Dots were evaluated for their visible light-activated antibacterial function, with the results showing the effective killing of not only Gram-positive but also the generally more resistant Gram-negative bacteria. The hybrid dots are clearly more potent antibacterial agents than their neat carbon dot counterparts. Mechanistically, the higher antibacterial performance of the CTiO2-Dots is attributed to their superior photoexcited state properties, which are reflected by the observed much brighter fluorescence emissions. Also considered and discussed is the possibility of additional contributions to the antibacterial activities due to the photosensitization of the nanoscale TiO2 by its doped core carbon nanoparticles.

Proteins are the most abundant biomolecules in living organisms and tissues and are also present in many natural and processed foods and beverages, as well as in pharmaceuticals and therapeutics. When exposed to UV-visible light, proteins containing endogenous or exogenous chromophores can undergo direct and indirect photochemical processes, resulting in protein modifications including oxidation of residues, cross-linking, proteolysis, covalent binding to molecules and interfaces, and conformational changes. When these modifications occur in an uncontrolled manner in a physiological context, they can lead to biological dysfunctions that ultimately result in cell death. However, rational design strategies involving light-activated protein modification have proven to be a valuable tool for the modulation of protein function or even for the construction of new biomaterials. This mini-review describes the fundamentals of photochemical processes in proteins and explores some of their emerging biomedical and nanobiotechnological applications, such as photodynamic therapy (PDT), photobonding for wound healing, photobioprinting, photoimmobilization of biosensors and enzymes for sensing, and biocatalysis, among others.

UNASSIGNED: Ischemic stroke becomes a major cause of death and disability. It can develop due to intravascular or cardiac thromboemboli. Animal models that reflect diverse stroke mechanisms remain under development. Using photochemical thrombosis, we developed a feasible zebrafish model according to the thrombus location (intracerebral vs. intracardiac). We validated the model using real-time imaging and thrombolytic agent.
UNASSIGNED: We used transgenic zebrafish larvae (flk:gfp), which express specific fluorescence in endothelial cells. We injected Rose Bengal, a photosensitizer as a mixture of photosensitizer, and a fluorescent agent into the cardinal vein of the larvae. We then evaluated real-time thrombosis in vivo by inducing thrombosis through exposure to a confocal laser (560 nm) and staining the blood flow (RITC-dextran). We validated intracerebral and intracardiac thrombotic models with checking the activity of tissue plasminogen activator (tPA).
UNASSIGNED: The photochemical agent induced the formation of intracerebral thrombi in transgenic zebrafish. Real-time imaging techniques confirmed the formation of the thrombi. The damage and apoptosis of the vessel\'s endothelial cells were seen in the in vivo model. An intracardiac thrombosis model was developed by the same method using photothrombosis, and the model was validated through thrombolysis by tPA.
UNASSIGNED: We developed and validated two zebrafish thrombosis models that are readily available, cost-effective, and intuitive for assessing the efficacy of thrombolytic agents. These models can be used for a broad spectrum of future studies, such as screening and efficacy assessment of new antithrombotic agents.

Over a period of ~2 wk, 5 adult beef cows developed severe necrotizing skin lesions on the face and neck shortly after being moved to a field with a cover crop of Brassica spp. turnips. We describe here the clinical signs, hematology, and serum chemistry results, as well as gross and histopathologic findings, from this outbreak. We made a presumptive diagnosis of Brassica-associated liver disease (BALD) based on the similarities in the history and diagnostic findings observed with previously reported cases of BALD from elsewhere in the world. BALD has not been reported previously in cattle in North America, to our knowledge, despite the increasing usage of cover crops to improve soil conditions and provide forage for livestock. After the presumptive diagnosis of BALD was made, the cattle were removed from the turnip field and no additional cases were noted by the producer. BALD is well known in other parts of the world, and veterinarians and diagnosticians should be aware of this condition given that the usage of cover crops is likely to continue to increase.

Commonly used peroxydisulfate (PS) or peroxymonosulfate (PMS) activation methods have been limited in their practical application due to certain drawbacks, such as high cost, high energy consumption and secondary pollution. In this study, a catalyst-free alizarin green (AG) self-activating PMS catalytic system was constructed based on photosensitization properties of dye, which ultimately achieved efficient degradation of the dye activator, also the target pollutant. Here, 52.5% of the 100 mL mixture of 10 mg/L AG decomposed within 60 min with 1 mM PMS under visible-light irradiation, thereby showing a strong pH adaptation. Mechanism of AG self-activating PMS was revealed that the photo-excited AG can effectively transfer photo-induced electrons to PMS for its activation, which generates reactive oxidizing species dominated by singlet oxygen (1O2), and supplemented by hydroxyl radical (•OH), superoxide radical (O2•-) and sulfate radical (SO4•-) to realize the efficient self-degradation of the dye pollutants. Moreover, such self-catalytic system operated well under natural sunlight irradiation, indicating the great application potential in the actual wastewater treatment. Herein, photosensitive dye acted as an ideal PMS activator realizing its efficient self-degradation, which provides a novel idea of \"using waste to treat waste\" for developing wastewater treatment process in a high-efficiency and low-consumption way.

A fundamental, Quantum Mechanical description of photoactivation of a generic photosensitizer and the ensuing transfer of energy to endogenous oxygen as part of the Type II pathway to photodamage during photodynamic therapy (PDT) is presented. The PS and molecular oxygen are approximated as two-electron molecules. Conservation of energy and of angular momenta of the two molecule system are abided via selection rules throughout the four-stage process, including initial states, absorption of a photon by the PS, conversion of the PS to an excited spin triplet via intersystem crossing (ISC), and the transition of molecular oxygen to an excited spin singlet state via a Triplet-Triplet Exchange of electrons with the PS. The provided description of photosensitization will provide students and researchers with a fundamental introduction to PDT, while offering the broader population of Quantum Mechanics and Physical Chemistry students an advanced example of quantum systems in an applied, medical context.

Photodynamic antimicrobial chemotherapy (PACT) is extensively studied as a strategic method to inactivate pathogenic microbes in wastewater for addressing the limitations associated with chlorination, ozonation, and ultraviolet irradiation as disinfection methods, which generally promote the development of resistant genes and harmful by-products such as trihalomethanes. PACT is dependent on photons, oxygen, and a photosensitizer to induce cytotoxic effects on various microbes by generating reactive oxygen species. Photosensitizers such as porphyrins have demonstrated significant microbial inactivation through PACT, hence now explored for wastewater phototreatment. This review aims to evaluate the efficacy of porphyrins and porphyrin-conjugates as photosensitizers for wastewater photoinactivation. Concerns relating to the application of photosensitizers in water treatment are also evaluated. This includes recovery and reuse of the photosensitizer when immobilized on solid supports.