-
The Science of the Total Environment Feb 2022Photochemical transformation of natural organic matter in aquatic environments strongly impacts the environmental behaviors of carbon, nutrients, and pollutants by... (Review)
Review
Photochemical transformation of natural organic matter in aquatic environments strongly impacts the environmental behaviors of carbon, nutrients, and pollutants by affecting their solubility, toxicity, bioavailability, and mobility. However, the role of particulate organic matter (POM) in environmental photogeochemistry has received much less attention than that of dissolved organic matter (DOM). In this study, a systematic overview was conducted to summarize the photodissolution and photoflocculation of POM in aquatic systems. The photodissolution of various POM, such as resuspended sediments and algal detritus, could be a potential and important source of DOM in the overlying waters, and these photoreleased DOM were dominated by humic-like components. The photogeochemistry of POM is thought to proceed via direct photochemical reactions and reactive radical-dominated indirect processes. Photodissolution can modify the bioavailability of organic matter and influence the biogeochemical cycling of nutrients, heavy metals, and organic pollutants. In addition, the photo-induced flocculation of DOM to POM could also influence the transport and transformation of organic matter and its associated pollutants. The photochemistry of POM can be significantly influenced by several environmental factors, including irradiation wavelength and intensity, organic matter properties, and radical oxygen species. POM photogeochemistry is one of the most important components of the global cycling of natural organic matter. Further studies regarding photogeochemistry should be conducted to overcome the potential problems arising from the concurrent photodegradation of organic matter and to further develop more filed investigations and analytical methods.
Topics: Particulate Matter; Photolysis; Solubility; Spectrometry, Fluorescence
PubMed: 34592285
DOI: 10.1016/j.scitotenv.2021.150467 -
Environmental Science and Pollution... May 2021As the presence of antibiotics in environmental waters enhances antimicrobial resistance, photolysis and heterogeneous photocatalysis of chloramphenicol (CAP) were...
Chemical and toxicological evaluation along with unprecedented transformation products during photolysis and heterogeneous photocatalysis of chloramphenicol in different aqueous matrices.
As the presence of antibiotics in environmental waters enhances antimicrobial resistance, photolysis and heterogeneous photocatalysis of chloramphenicol (CAP) were evaluated in deionized water (DW) and in sewage treatment plant (STP) effluent under black light and solar irradiation. Processes were compared in terms of CAP degradation, reaction kinetics, and electrical energy per order, as well as regarding theoretical toxicity, biodegradability, carcinogenicity, and mutagenicity of transformation products (TPs). Rate constants obtained under photolysis (0.008 min) and heterogeneous photocatalysis (0.18 min) only differed in DW. This is due to the generation of photo-active reactive oxygen species (HO and HO/O) under photolysis in STP effluent, as verified by experiments in the presence of 2-propanol and chloroform. Natural organic matter and HCO were the main responsible for reducing CAP degradation in STP effluent. Fifteen TPs were identified during both processes in DW, 13 of which are unprecedented. TPs were formed mainly via HO preferential attack on the aromatic ring and on the α-carbon, and some of them were classified as persistent and toxic, genotoxic, or carcinogenic by Toxtree software. Results confirm that solar photocatalysis is less costly than to photocatalysis under black light for wastewater treatment.
Topics: Chloramphenicol; Kinetics; Photolysis; Water; Water Pollutants, Chemical
PubMed: 32638314
DOI: 10.1007/s11356-020-09756-3 -
Journal of Medicinal Chemistry Sep 2022Targeted degradation of proteins, especially those regarded as undruggable or difficult to drug, attracts wide attention to develop novel therapeutic strategies....
Targeted degradation of proteins, especially those regarded as undruggable or difficult to drug, attracts wide attention to develop novel therapeutic strategies. Glutathione peroxidase 4 (GPX4), the key enzyme regulating ferroptosis, is currently a target with just covalent inhibitors. Here, we developed a targeted photolysis approach and achieved efficient degradation of GPX4. The photodegradation-targeting chimeras (PDTACs) were synthesized by conjugating a clinically approved photosensitizer (verteporfin) to noninhibitory GPX4-targeting peptides. These chimeras selectively degraded the target protein in both cell lysates and living cells upon red-light irradiation. The targeted photolysis of GPX4 resulted in dominant ferroptotic cell death in malignant cancer cells. Moreover, the dying cells resulting from the PDTACs exhibited potent immunogenicity in vitro and efficiently elicited antitumor immunity in vivo. Our approach therefore provides a novel method to induce GPX4 dysfunction based on noncovalent binding and specifically trigger immunogenic ferroptosis, which may boost the application of ferroptosis in cancer immunotherapy.
Topics: Ferroptosis; Phospholipid Hydroperoxide Glutathione Peroxidase; Photolysis; Photosensitizing Agents; Verteporfin
PubMed: 36066386
DOI: 10.1021/acs.jmedchem.2c00855 -
Environmental Research Aug 2023Dissolved organic matter (DOM) widely exists in aquatic environment and plays a critical role in environmental photochemical reaction. The photochemical behaviors of DOM... (Review)
Review
Dissolved organic matter (DOM) widely exists in aquatic environment and plays a critical role in environmental photochemical reaction. The photochemical behaviors of DOM in sunlit surface waters have received widely attention because its photochemical effects for some coexisted substances in aquatic environment, especially for organic micropollutants degradation. Therefore, to gain a comprehensive understanding of the photochemical properties and environmental effects of DOM, we reviewed the influence of sources on the structure and composition of DOM with relevant identified techniques to analysis functional groups. Additionally, identification and quantification for reactive intermediates are discussed with a focus on influencing factors to produce reactive intermediates by DOM under solar irradiation. These reactive intermediates can promote the photodegradation of organic micropollutants in the environmental system. In future, attention should be paid to the photochemical properties of DOM and environmental effects in real environmental system and development of advanced techniques to study DOM.
Topics: Dissolved Organic Matter; Photolysis; Solar Energy
PubMed: 37209983
DOI: 10.1016/j.envres.2023.116174 -
Indoor Air Jan 2022We made intensive measurements of wavelength-resolved spectral irradiance in a test house during the HOMEChem campaign and report diurnal profiles and two-dimensional...
We made intensive measurements of wavelength-resolved spectral irradiance in a test house during the HOMEChem campaign and report diurnal profiles and two-dimensional spatial distribution of photolysis rate constants (J) of several important indoor photolabile gases. Results show that sunlight entering through windows, which was the dominant source of ultraviolet (UV) light in this house, led to clear diurnal cycles, and large time- and location-dependent variations in local gas-phase photochemical activity. Local J values of several key indoor gases under direct solar illumination were 1.8-7.4 times larger-and more strongly dependent on time, solar zenith angle, and incident angle of sunlight relative to the window-than under diffuse sunlight. Photolysis rate constants were highly spatially heterogeneous and fast photochemical reactions in the gas phase were generally confined to within tens of cm of the region that were directly sunlit. Opening windows increased UV photon fluxes by 3 times and increased predicted local hydroxyl radical (OH) concentrations in the sunlit region by 4.5 times to 3.2 × 10 molec cm due to higher J values and increased contribution from O photolysis. These results can be used to improve the treatment of photochemistry in indoor chemistry models and are a valuable resource for future studies that use the publicly available HOMEChem measurements.
Topics: Air Pollution, Indoor; Gases; Hydroxyl Radical; Nitrous Acid; Photolysis
PubMed: 34854500
DOI: 10.1111/ina.12966 -
Macromolecular Rapid Communications Aug 2022The photochemical reaction is a very important type of chemical reaction. Visualizing and controlling photo-mediated reactions is a long-standing goal and challenge. In... (Review)
Review
The photochemical reaction is a very important type of chemical reaction. Visualizing and controlling photo-mediated reactions is a long-standing goal and challenge. In this regard, single-molecule electrical detection with label-free, real-time, and in situ characteristics has unique advantages in monitoring the dynamic process of photoreactions at the single-molecule level. In this review, a valuable summary of the latest process of single-molecule photochemical reactions based on single-molecule electrical platforms is provided. The single-molecule electrical detection platforms for monitoring photoreactions are displayed, including their fundamental principles, construction methods, and practical applications. The single-molecule studies of two different types of light-mediated reactions are summarized as below: i) photo-induced reactions, including reversible cyclization, conformational isomerization, and other photo-related reactions; ii) plasmon-mediated photoreactions, including reaction mechanisms and concrete examples, such as plasmon-induced photolysis of SS/OO bonds and tautomerization of porphycene. In addition, the prospects for future research directions and challenges in this field are also discussed.
Topics: Nanotechnology; Photolysis
PubMed: 35150177
DOI: 10.1002/marc.202200017 -
Environmental Science & Technology Aug 2019Perfluoroketones, used as replacement to halons and CFCs, are excluded from the Montreal Protocol because they are considered as nonozone depleting substances. However,...
Perfluoroketones, used as replacement to halons and CFCs, are excluded from the Montreal Protocol because they are considered as nonozone depleting substances. However, their chemical structure makes them possible greenhouse gases if their atmospheric lifetimes are long enough. To assess that possibility, we investigated the photolysis of perfluoro-2-methyl-3-pentanone (PF-2M3P), and perfluoro-3-methyl-2-butanone (PF-3M2B) using outdoor atmospheric simulation chambers. In addition, the photolysis of a non fluorinated pentanone (2-methyl-3-pentanone, 2M3P) was studied. The results showed that photolysis is the dominant loss pathway of PF-2M3P and PF-3M2B in the troposphere whereas 2M3P is lost by both photolysis and gas phase reaction with atmospheric oxidants. The photolysis effective quantum yields of PF-2M3P, PF-3M2B, and 2M3P were estimated and some of the main products identified. The photolysis of PF-2M3P and PF-3M2B was found to have a minor impact on the atmospheric burden of fluorinated acids. The atmospheric lifetimes of PF-2M3P, PF-3M2B, and 2M3P were estimated to 3-11 days, ∼13 days, and 1-2 days, respectively. Combining the obtained data, it has been concluded that with 100-year time horizon global warming potentials (GWP) equivalent to <0.21, ∼0.29, and ≤1.3 × 10 for PF-2M3P, PF-3M2B, and 2M3P, respectively, these compounds will have a negligible impact on global warming.
Topics: Atmosphere; Butanones; Global Warming; Pentanones; Photolysis
PubMed: 31291100
DOI: 10.1021/acs.est.9b02974 -
ACS Macro Letters Apr 2021Herein, we demonstrate that the photochemical cleavage of linear polymers containing a midchain photocleavable moiety strongly depends on the chain length. Based on an...
Herein, we demonstrate that the photochemical cleavage of linear polymers containing a midchain photocleavable moiety strongly depends on the chain length. Based on an -nitrobenzyl (NB) difunctional reversible addition-fragmentation chain-transfer agent, well-defined poly(methyl acrylate)s ( = 1.59-67.6 kg mol, = 1.3-1.4) were synthesized following a core-first approach. Photolysis at λ = 350 nm of the -nitrobenzyl moiety led to the generation of equally sized polymer segments. The rate of NB-driven polymer fragmentation, which can be well described by first-order kinetics, strongly increases with increasing molecular weight in a nonlinear fashion, potentially caused by entropic considerations and is compared to the ideal chain model. The current study thus demonstrates that polymer photolysis is dependent on the polymer chain length, with critical implications for photocleavable network design.
Topics: Molecular Weight; Photolysis; Polymers
PubMed: 35549234
DOI: 10.1021/acsmacrolett.1c00057 -
Environmental Science & Technology Sep 2018Determining the influence of higher order structure on UVC photolysis will help inform predictions of nucleic acid fate and microorganism inactivation. We measured the...
Determining the influence of higher order structure on UVC photolysis will help inform predictions of nucleic acid fate and microorganism inactivation. We measured the direct UV photolysis kinetics of four model viral genomes composed of single-stranded and double-stranded RNA (ssRNA and dsRNA, respectively), as well as single-stranded and double-stranded DNA (ssDNA and dsDNA, respectively), in ultrapure water, in phosphate buffered saline (PBS), and encapsidated in their native virus particles. The photolysis rate constants of naked nucleic acids measured by qPCR (RT-qPCR for RNA) and normalized by the number of bases measured in a particular sequence exhibited the following trend: ssDNA > ssRNA ≈ dsDNA > dsRNA. In PBS, naked ssRNA bases reacted, on average, 24× faster than the dsRNA bases, whereas naked ssDNA bases reacted 4.3× faster than dsDNA bases. Endogenous indirect photolysis involving O and ·OH was ruled out as a major contributing factor in the reactions. A comparison of our measured rate constants with rate constants reported in the literature shows a general agreement among the nucleic acid UV direct photolysis kinetics. Our results underscore the high resistance of dsRNA to UVC photolysis and demonstrate the role that nucleic acid structure and solution chemistry play in photoreactivity.
Topics: DNA; DNA, Single-Stranded; Genome, Viral; Photolysis; RNA
PubMed: 30106282
DOI: 10.1021/acs.est.8b02308 -
Journal of Pharmaceutical and... May 2023Tegoprazan is a novel orally active potassium-competitive acid blocker (P-CAB), capable of binding to the K binding site of H/K-ATPase in a reversible way to inhibit...
Tegoprazan is a novel orally active potassium-competitive acid blocker (P-CAB), capable of binding to the K binding site of H/K-ATPase in a reversible way to inhibit gastric acid secretion. Tegoprazan has been approved for treating acid-related diseases. In this study, stress testings of tegoprazan were performed under various conditions, including hydrolysis (acidic, alkaline, and neutral), oxidation, photolysis, and thermal stress. Tegoprazan showed instability in acidic, alkaline, and oxidative conditions. Eight degradation products (DPs) were identified. The DPs were characterized by LC-HRMS, LC-MS, or GC-Q-TOF-MS. Meanwhile, DP-1, DP-2 and DP-3 were successfully synthesized and confirmed by NMR. The degradation pathway of tegoprazan was summarized. To the best of our knowledge, this is the first study on the forced degradation of tegoprazan.
Topics: Chromatography, Liquid; Gas Chromatography-Mass Spectrometry; Tandem Mass Spectrometry; Drug Stability; Hydrolysis; Oxidation-Reduction; Photolysis; Chromatography, High Pressure Liquid
PubMed: 36921447
DOI: 10.1016/j.jpba.2023.115323