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Journal of Agricultural and Food... Nov 2023Caged plant growth regulators (caged PGRs) that release bioactive molecules under irradiation are critical in enhancing the efficacy and mitigating the negative...
Caged plant growth regulators (caged PGRs) that release bioactive molecules under irradiation are critical in enhancing the efficacy and mitigating the negative environmental effects of PGRs. The synthetically derived plant growth inhibitor -16,17-dihydro-gibberellin A5-13-acetate (DHGA) regulates the development and stress resilience of plants. We report here the conception of novel caged DHGA derivatives wherein the photoremovable protecting groups (PRPGs) serve not only to enable light-controlled release but also to protect the carboxyl group during chemical synthesis. Three -nitrobenzyl-based caged DHGA derivatives with different substituents on the nitrobenzyl moiety were obtained and evaluated for their properties and . The photolysis half-life values of caged DHGA derivatives , , and under a UV lamp were 15.6 h, 1.2 h, and 28.2 h, respectively. Experiments showed that 0.2 mM of the caged compounds significantly inhibited the growth of the model plant and important crop rice in a precise photoactivated form.
Topics: Plant Growth Regulators; Gibberellins; Acetates; Photolysis; Arabidopsis
PubMed: 37878916
DOI: 10.1021/acs.jafc.3c05259 -
Water Environment Research : a Research... Aug 2023High concentrations of the most consumed pharmaceuticals, caffeine and paracetamol, have been observed globally in wastewater treatment plant discharge. Here, we assess...
High concentrations of the most consumed pharmaceuticals, caffeine and paracetamol, have been observed globally in wastewater treatment plant discharge. Here, we assess the potential for photodegradation of caffeine and paracetamol residues at concentrations like those observed in treated wastewater discharges to the environment. Laboratory assays were used to measure rates of photodegradation of these two compounds both in distilled water and in natural river water with leaf litter leachate. When exposed to artificial light simulating natural sunlight, the half-life values of caffeine and paracetamol were significantly shorter than in the dark. The presence of organic matter increased caffeine and paracetamol half-life by lessening the photolytic effect. These results suggest that photolysis is a substantial contributor to the degradation of caffeine and paracetamol. The findings contribute to our understanding of persistence of pharmaceuticals in treated wastewater discharge. PRACTITIONER POINTS: The photodegradation of caffeine and paracetamol residues in surface water was examined. With leaf litter leachate, caffeine and paracetamol were photodegraded in distilled and natural river water in laboratory. Caffeine's half-life ranged from 2.3 to 16.2 days under artificial sunlight andparacetamols from 4.3 to 12.2 days. When incubated in the dark, the half-life for both compounds exceeded 4 weeks. Organic matter decreased the photolytic action of caffeine and paracetamol.
Topics: Water; Wastewater; Photolysis; Caffeine; Acetaminophen; Sunlight; Water Pollutants, Chemical; Pharmaceutical Preparations
PubMed: 37429828
DOI: 10.1002/wer.10909 -
The Science of the Total Environment Nov 2023Algal organic matter (AOM) is a major component of dissolved organic matter (DOM) in eutrophic lakes and could impact the photodegradation of neurotoxic methylmercury...
Algal organic matter (AOM) is a major component of dissolved organic matter (DOM) in eutrophic lakes and could impact the photodegradation of neurotoxic methylmercury (MeHg) in water. Predicting these effects, however, is challenging, largely due to the dynamic changes of AOM during algal decomposition. Here, we investigated the effects of AOM on MeHg photodegradation throughout the algal decomposition process and elucidated these effects by characterizing dynamic changes of AOM and exploring the respective roles of various reactive oxygen species (ROS). Our results reveal that AOM derived from algal decomposition significantly inhibits MeHg photodegradation, and the extent of this inhibition varies depending on the specific lakes (8-21 %, p < 0.05) and their eutrophication states (16-28 %, p < 0.05). The inhibitory effect gradually weakened as the decomposition progressed, which may be attributed to the dynamic changes in the quantity and quality of AOM. Moreover, hydroxyl radical (·OH) was found to be the main contributor in driving MeHg photodegradation (15-23 %) during the early stages of decomposition (day 0-3), while in the later stage (day 12-24), the role of singlet oxygen (O, 15-20 %) and (DOM*, 21-30 %) gradually strengthened and these three ROS jointly drove MeHg photodegradation. Based on our findings and recent studies, we propose that AOM derived from algal decomposition plays a vital role in increasing the risk of MeHg in eutrophic lakes. It promotes MeHg formation while simultaneously inhibiting its photodegradation. Integrating AOM-MeHg interactions into Hg biogeochemical cycling models would reduce uncertainties when predicting MeHg risks.
Topics: Methylmercury Compounds; Photolysis; Reactive Oxygen Species; Lakes; Water Pollutants, Chemical; Water
PubMed: 37474073
DOI: 10.1016/j.scitotenv.2023.165661 -
The Science of the Total Environment Jul 2023VUV photolysis presents a simple process for VOCs degradation, while the poor mineralization rate and extensive by-products greatly limit its application. In this study,...
VUV photolysis presents a simple process for VOCs degradation, while the poor mineralization rate and extensive by-products greatly limit its application. In this study, the contribution and synergy between •OH and •O to toluene degradation in the VUV-based process were comprehensively investigated by controlling water and oxygen in the gas flow. It was found that •OH promoted the initial degradation of toluene and macromolecular intermediates, while •O dominated toluene mineralization by boosting the formation of small molecules and CO. Compared with the •OH-dominated VUV photolysis, the presence of catalyst greatly changed the degradation pathway, promoted toluene mineralization into CO and reduced health toxicity via promoting •O formation. This study originally focuses on the key role of •O in VOCs deep oxidation and provides an effective strategy to boost its clean mineralization via the VUV-based process.
PubMed: 37127161
DOI: 10.1016/j.scitotenv.2023.163806 -
Environmental Technology Nov 2023This study discussed the effect of ferric salt addition on UV/electro-chlorine advanced oxidation process using a train of electrolytic and UV flow cells with an...
This study discussed the effect of ferric salt addition on UV/electro-chlorine advanced oxidation process using a train of electrolytic and UV flow cells with an ozone-free low-pressure mercury vapour lamp (total irradiance:0.60 W at 254 nm). Ferric salt addition enhanced 1,4-dioxane degradation at an electrolytic current of 0.100 A. By contrast, an inhibitory effect of ferric salt addition was observed at a current of 0.500 A. The enhanced accumulation of free chlorine at a current of 0.500 A directly decreased the 1,4-dioxane degradation rate by scavenging reactive radicals like HO˙ and Cl˙. However, at an electrolytic current of 0.100 A, UV irradiance was relatively excessive for electrochemical chlorine production. The excess UV energy enhanced the photoreduction of FeOH, followed by the Fenton-type reaction of Fe and HOCl, which produced HO˙ and consumed free chlorine. As a result, the free chlorine concentration decreased, and the reaction efficiency between the reactive radicals and 1,4-dioxane improved. Thus, the addition of ferric salt to a UV/electro-chlorine system is recommended when the UV irradiance in the system is excessive compared to the electrochemical chlorine supply.
PubMed: 37955858
DOI: 10.1080/09593330.2023.2283800 -
Journal of Environmental Sciences... Oct 2023Daytime HONO photolysis is an important source of atmospheric hydroxyl radicals (OH). Knowledge of HONO formation chemistry under typical haze conditions, however, is...
Daytime HONO photolysis is an important source of atmospheric hydroxyl radicals (OH). Knowledge of HONO formation chemistry under typical haze conditions, however, is still limited. In the Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain in 2018, we investigated the wintertime HONO formation and its atmospheric implications at a rural site Gucheng. Three different episodes based on atmospheric aerosol loading levels were classified: clean periods (CPs), moderately polluted periods (MPPs) and severely polluted periods (SPPs). Correlation analysis revealed that HONO formation via heterogeneous conversion of NO was more efficient on aerosol surfaces than on ground, highlighting the important role of aerosols in promoting HONO formation. Daytime HONO budget analysis indicated a large missing source (with an average production rate of 0.66 ± 0.26, 0.97 ± 0.47 and 1.45 ± 0.55 ppbV/hr for CPs, MPPs and SPPs, respectively), which strongly correlated with photo-enhanced reactions (NO heterogeneous reaction and particulate nitrate photolysis). Average OH formation derived from HONO photolysis reached up to (0.92 ± 0.71), (1.75 ± 1.26) and (1.82 ± 1.47) ppbV/hr in CPs, MPPs and SPPs respectively, much higher than that from O photolysis (i.e., (0.004 ± 0.004), (0.006 ± 0.007) and (0.0035 ± 0.0034) ppbV/hr). Such high OH production rates could markedly regulate the atmospheric oxidation capacity and hence promote the formation of secondary aerosols and pollutants.
Topics: Nitrous Acid; Environmental Pollutants; Nitrogen Dioxide; China; Aerosols
PubMed: 37336612
DOI: 10.1016/j.jes.2022.09.034 -
The Journal of Physical Chemistry. A Nov 2023Enhanced photolysis of particulate nitrate (pNO) to form photolabile species, such as gas-phase nitrous acid (HONO), has been proposed as a potential mechanism to...
Enhanced photolysis of particulate nitrate (pNO) to form photolabile species, such as gas-phase nitrous acid (HONO), has been proposed as a potential mechanism to recycle nitrogen oxides (NO) in the remote boundary layer ("renoxification"). This article presents a series of laboratory experiments aimed at investigating the parameters that control the photolysis of pNO and the efficiency of HONO production. Filters on which artificial or ambient particles had been sampled were exposed to the light of a solar simulator, and the formation of HONO was monitored under controlled laboratory conditions. The results indicate that the photolysis of pNO is enhanced, compared to the photolysis of gas-phase HNO, at low pNO levels, with the enhancement factor reducing at higher pNO levels. The presence of cations (Na) and halides (Cl) and photosensitive organic compounds (imidazole) also enhance pNO photolysis, but other organic compounds such as oxalate and succinic acid have the opposite effect. The precise role of humidity in pNO photolysis remains unclear. While the efficiency of photolysis is enhanced in deliquescent particles compared to dry particles, some of the experimental results suggest that this may not be the case for supersaturated particles. These experiments suggest that both the composition and the humidity of particles control the enhancement of particulate nitrate photolysis, potentially explaining the variability in results among previous laboratory and field studies. HONO observations in the remote marine boundary layer can be explained by a simple box-model that includes the photolysis of pNO, in line with the results presented here, although more experimental work is needed in order to derive a comprehensive parametrization of this process.
PubMed: 37879076
DOI: 10.1021/acs.jpca.3c03853 -
Journal of Pharmaceutical and... Sep 20235-Hydroxymethyl-2-furaldehyde (5-HMF) is a kind of aldehyde compound with highly active furan ring, which is generated by dehydration of glucose, fructose, and other...
5-Hydroxymethyl-2-furaldehyde (5-HMF) is a kind of aldehyde compound with highly active furan ring, which is generated by dehydration of glucose, fructose, and other monosaccharides. It widely exists in drugs, foods, health products, cosmetics, and traditional Chinese medicine preparations with high sugar content. Due to the toxicity, the concentration of 5-HMF was always monitored to identify non-conformities and adulteration, as well as ensure the process efficiency, traceability and safety in foods or drugs in the pharmacopoeias of various countries. Herein, a comprehensive forced degradation study was performed to characterize the degradation products (DPs) of 5-HMF under hydrolytic (neutral, acidic, and alkaline) degradation, oxidative, thermal, humidity, and photolytic degradation conditions. A total of five degradants were identified, and two of them (DP-3 and DP-5) were novel DPs first reported in our study. Major DPs (i.e., DP-1 and DP-2) with relatively high peak areas were isolated using semi-preparative HPLC and characterized by LC-LTQ/Orbitrap and NMR. 5-HMF was only stable in alkaline hydrolysis condition. In addition, the degradation pathways and mechanism of these DPs were also explained using LC-LTQ/Orbitrap. In silico toxicity and metabolism behavior of the DPs were evaluated using Derek Nexus and Meteor Nexus software, respectively. The predicted toxicity data indicated that both the drug 5-HMF and its DPs bear the potential of hepatotoxicity, mutagenicity, chromosome damage, and skin sensitisation. Our research may be beneficial for the quality control and suitable storage conditions of 5-HMF.
Topics: Chromatography, High Pressure Liquid; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Magnetic Resonance Spectroscopy; Drug Stability; Hydrolysis; Oxidation-Reduction; Photolysis
PubMed: 37210891
DOI: 10.1016/j.jpba.2023.115470 -
Bioorganic & Medicinal Chemistry Letters Aug 2023Previously we have demonstrated that light can be used to control the release of insulin in diabetic animals, followed by a reduction in blood glucose. This is...
Previously we have demonstrated that light can be used to control the release of insulin in diabetic animals, followed by a reduction in blood glucose. This is accomplished using a photoactivated depot (PAD) of insulin injected into the skin, and irradiated by a small external LED light source. In this work for the first time we demonstrate dose-response, showing that we can vary insulin release and commensurate blood glucose reduction by varying the amount of light administered. In addition to demonstrating dose-response, we have shown multi-day depot response, with insulin being released on two different days from the same depot. The material used in these studies was CD-insulin, a form of insulin that has a highly non-polar cyclododecyl group attached, markedly reducing the solubility of the modified material, and allowing it to form a depot upon injection. Upon photolysis, the cyclododecyl group is removed, releasing fully native, soluble insulin. Variable response and multi-day response as demonstrated strongly support the potential utility of the PAD approach for the variable and extended release of therapeutic peptides.
Topics: Animals; Insulin; Blood Glucose; Skin; Solubility; Photolysis
PubMed: 37369330
DOI: 10.1016/j.bmcl.2023.129388 -
Chemosphere Mar 2024This study aims to provide a comprehensive evaluation of the photocatalytic properties and performance of the Cu-Ti-O heterojunction sonochemically embedded in the...
Insightful properties-performance study of Ti-Cu-O heterojunction sonochemically embedded in mesoporous silica matrix for efficient tetracycline adsorption and photodegradation: RSM and ANN-based modeling and optimization.
This study aims to provide a comprehensive evaluation of the photocatalytic properties and performance of the Cu-Ti-O heterojunction sonochemically embedded in the mesoporous silica matrix. Various characterization analyses and adsorption/photodegradation experiments were performed to assess the potential of the sample for tetracycline (TC) removal. The characterization results indicated that sonication contributes to better dispersion of Ti-Cu-O species, resulting in more uniform particle sizes, stronger semiconductors-silica interaction, and less agglomeration. Furthermore, sonication significantly affected the optical nanocomposite features, leading to an improvement in charge carrier separation and a decrease in the band gap of Ti-Cu-Si (S) by approximately 2.6 eV. Based on the textural results, the ultrasound microjets increased the surface area and pore volume, which facilitate mass transfer and provide suitable adsorption sites for TC molecules. Accordingly, Cu-Ti-Si (S) demonstrated higher adsorption capacity (0.051 g TC/g adsorbent) and eliminated TC significantly faster (0.0054 L.mg.min) than a non-sonicated sample during 120 min of irradiation, resulting in 2.84 times improvement in the constant rate. In addition, experimental results were accurately modeled using a central composite design in combination with response surface methodology (RSM) and artificial neural networks (ANN) to predict and optimize TC photodegradation. Both RSM and ANN models revealed excellent predictability for TC degradation efficiency, with R = 99.47 and 99.71%, respectively. At optimal operational conditions (C = 20 ppm, photocatalyst dosage = 1.15 g.L, pH = 9, and irradiation time = 100 min), more than 95% and 87% of TC were degraded within the UV (375 W) and simulated solar light (400 W) irradiation periods, respectively. It was observed that the Cu-Ti-Si (S) nanocomposite maintained remarkable stability after four cycles with only a negligible 3% loss of activity, owing to the superior interaction between the bimetallic heterojunction and the silica matrix.
Topics: Photolysis; Silicon Dioxide; Adsorption; Titanium; Tetracycline; Anti-Bacterial Agents; Neural Networks, Computer
PubMed: 38228191
DOI: 10.1016/j.chemosphere.2024.141223