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2.
Sci Rep ; 11(1): 5070, 2021 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-33658595

RESUMEN

Inactivation technology for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is certainly a critical measure to mitigate the spread of coronavirus disease 2019 (COVID-19). A deep ultraviolet light-emitting diode (DUV-LED) would be a promising candidate to inactivate SARS-CoV-2, based on the well-known antiviral effects of DUV on microorganisms and viruses. However, due to variations in the inactivation effects across different viruses, quantitative evaluations of the inactivation profile of SARS-CoV-2 by DUV-LED irradiation need to be performed. In the present study, we quantify the irradiation dose of DUV-LED necessary to inactivate SARS-CoV-2. For this purpose, we determined the culture media suitable for the irradiation of SARS-CoV-2 and optimized the irradiation apparatus using commercially available DUV-LEDs that operate at a center wavelength of 265, 280, or 300 nm. Under these conditions, we successfully analyzed the relationship between SARS-CoV-2 infectivity and the irradiation dose of the DUV-LEDs at each wavelength without irrelevant biological effects. In conclusion, total doses of 1.8 mJ/cm2 for 265 nm, 3.0 mJ/cm2 for 280 nm, and 23 mJ/cm2 for 300 nm are required to inactivate 99.9% of SARS-CoV-2. Our results provide quantitative antiviral effects of DUV irradiation on SARS-CoV-2, serving as basic knowledge of inactivation technologies against SARS-CoV-2.


Asunto(s)
/efectos de la radiación , Terapia Ultravioleta/métodos , Inactivación de Virus/efectos de la radiación , /epidemiología , Humanos , Rayos Ultravioleta , Virosis/prevención & control
3.
Biomed Environ Sci ; 34(2): 101-109, 2021 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-33685568

RESUMEN

Objective: To assess the association of socioeconomic status with the burden of cataract blindness in terms of year lived with disability (YLD) rates and to determine whether ultraviolet radiation (UVR) levels modify the effect of socioeconomic status on this health burden. Methods: National and subnational age-standardized YLD rates associated with cataract-related blindness were derived from the Global Burden of Disease (GBD) study 2017. The human development index (HDI) from the Human Development Report was used as a measure of socioeconomic status. Estimated ground-level UVR exposure was obtained from the Ozone Monitoring Instrument (OMI) dataset of the National Aeronautics and Space Administration (NASA). Results: Across 185 countries, socioeconomic status was inversely associated with the burden of cataract blindness. Countries with a very high HDI had an 84% lower age-standardized YLD rate [95% confidence interval ( CI): 60%-93%, P < 0.001] than countries with a low HDI; for high-HDI countries, the proportion was 76% (95% CI: 53%-88%, P < 0.001), and for medium-HDI countries, the proportion was 48% (95% CI: 15%-68%, P = 0.010; P for trend < 0.001). The interaction analysis showed that UVR exposure played an interactive role in the association between socioeconomic status and cataract blindness burden ( P value for interaction = 0.047). Conclusion: Long-term high-UVR exposure amplifies the association of poor socioeconomic status with the burden of cataract-related blindness. The findings emphasize the need for strengthening UVR exposure protection interventions in developing countries with high-UVR exposure.


Asunto(s)
Ceguera/epidemiología , Catarata/epidemiología , Carga Global de Enfermedades , Rayos Ultravioleta/efectos adversos , Ceguera/etiología , Catarata/etiología , Femenino , Carga Global de Enfermedades/estadística & datos numéricos , Humanos , Masculino , Años de Vida Ajustados por Calidad de Vida , Clase Social , Factores Socioeconómicos
4.
Huan Jing Ke Xue ; 42(2): 860-866, 2021 Feb 08.
Artículo en Chino | MEDLINE | ID: mdl-33742880

RESUMEN

To study the effect of combined ultraviolet (UV) chloramine disinfection on viruses in a drinking water supply system, a full-scale experiment was conducted to analyze the distribution, variability, community structure, and hosts of viruses using metagenomics. The results showed that the combined UV chloramine process reduced the number of virus species (6.13%) and gene abundance (51.97%) but did not completely remove the viruses from the water. The United States Environmental Protection Agency (USEPA) report that virus removal efficiencies from water can reach 99%-99.99% based on culturing methods. However, in this study, metagenomic analysis indicated a total virus removal rate of only 93.46%. Therefore, the detection of viruses in water using culturing method cannot reliably detect viruses in drinking water. Caudovirales are the most abundant type of virus in water supply systems and are sensitive to chloramine disinfection. Lentivirus, as a virus that can infect humans and vertebrates, has strong resistance to UV and chloramine disinfection. The main virus hosts in the studied water supply system were bacteria (61.50%). The viruses in the raw water were mainly parasitic in Synechococcus. The dominant virus host was Pseudomonas in both the effluent water and pipe network water. The gene abundance of the Pseudomonas aeruginosa host in the pipe network increased by 342.62%, which requires further attention as a virus risk in pipe network systems. Overall, combined UV chloramine disinfection was more effective at the removal of virus hosts than single UV disinfection (51.97% compared to 0.79%).


Asunto(s)
Agua Potable , Virus , Purificación del Agua , Cloraminas/farmacología , Desinfección , Humanos , Rayos Ultravioleta , Estados Unidos , Abastecimiento de Agua
5.
Int J Nanomedicine ; 16: 1789-1804, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33688191

RESUMEN

Background: SARS-COVID-2 has recently been one of the most life-threatening problems which urgently needs new therapeutic antiviral agents, especially those of herbal origin. Purpose: The study aimed to load acaciin (ACA) into the new self-assembled nanofibers (NFs) followed by investigating their possible antiviral effect against bovine coronavirus (BCV) as a surrogate model for SARS-COV-2. Methods: ACA was identified using 1H-NMR and DEPT-Q 13C-NMR spectroscopy, the molecular docking study was performed using Autodock 4 and a modification of the traditional solvent injection method was applied for the synthesis of the biodegradable NFs. Different characterization techniques were used to inspect the formation of the NFs, which is followed by antiviral investigation against BCV as well as MTT assay using MDBK cells. Results: Core/shell NFs, ranging between 80-330 nm with tiny thorn-like branches, were formed which attained an enhanced encapsulation efficiency (97.5 ± 0.53%, P<0.05) and a dual controlled release (a burst release of 65% at 1 h and a sustained release up to >24 h). The antiviral investigation of the formed NFs revealed a significant inhibition of 98.88 ± 0.16% (P<0.05) with IC50 of 12.6 µM against BCV cells. Conclusion: The results introduced a new, time/cost-saving strategy for the synthesis of biodegradable NFs without the need for electric current or hazardous cross-linking agents. Moreover, it provided an innovative avenue for the discovery of drugs of herbal origin for the fight against SARS-CoV-2 infection.


Asunto(s)
Coronavirus Bovino/efectos de los fármacos , Glicósidos/farmacología , Nanofibras/química , /efectos de los fármacos , Antivirales/química , Antivirales/farmacología , /virología , Línea Celular , Glicósidos/química , Glicósidos/aislamiento & purificación , Glicósidos/uso terapéutico , Humanos , Ligandos , Modelos Biológicos , Simulación del Acoplamiento Molecular , Nanofibras/ultraestructura , Solventes , Rayos Ultravioleta
6.
Food Chem ; 352: 129350, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33657481

RESUMEN

Fermented cassava products are important starchy food staples in South America. The quality of the products is affected by the baking expansion ability of the dough, which is in turn influenced by the starch fermentation process and drying method employed. We investigated the structural properties of cassava starch after different fermentation and drying treatments, and the effect of starch structure on scalding of dough and baking expansion ability. Fermentation combined with either exposure to sunlight or UV light treatment resulted in high cassava starch baking expansion. Moreover, we observed decreased crystallinity and increased disordered crystalline regions with lower molecular weight in the two types of starch-fermented combined with sunlight or UV light treatment-and both appeared to have a continuous network structure and polarized cross in scalded dough, which are conducive to holding gas and losing water, thus promoting high baking expansibility.


Asunto(s)
Manipulación de Alimentos , Manihot/química , Almidón/química , Desecación , Fermentación , Manihot/efectos de la radiación , Peso Molecular , Luz Solar , Rayos Ultravioleta
7.
Molecules ; 26(4)2021 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-33669268

RESUMEN

Stilbenes or stilbenoids, major polyphenolic compounds of the bark of Norway spruce (Picea abies L. Karst), have potential future applications as drugs, preservatives and other functional ingredients due to their antioxidative, antibacterial and antifungal properties. Stilbenes are photosensitive and UV and fluorescent light induce trans to cis isomerisation via intramolecular cyclization. So far, the characterizations of possible new compounds derived from trans-stilbenes under UV light exposure have been mainly tentative based only on UV or MS spectra without utilizing more detailed structural spectroscopy techniques such as NMR. The objective of this work was to study the stability of biologically interesting and readily available stilbenes such as astringin and isorhapontin and their aglucones piceatannol and isorhapontigenin, which have not been studied previously. The effects of fluorescent and UV light and storage on the stability of trans stilbenes were assessed and the identification and characterisation of new compounds formed during our experiments were carried out by chromatographic (HPLC, GC) and spectroscopic techniques (UV, MS, NMR). The stilbenes undergo a trans to cis isomerisation under extended UV irradiation by intramolecular cyclisation (by the formation of a new C-C bond and the loss of two hydrogens) to phenanthrene structures. The characterised compounds are novel and not described previously.


Asunto(s)
Luz , Picea/química , Corteza de la Planta/química , Raíces de Plantas/química , Estilbenos/química , Estilbenos/aislamiento & purificación , Fluorescencia , Cromatografía de Gases y Espectrometría de Masas , Isomerismo , Soluciones , Rayos Ultravioleta
8.
Molecules ; 26(4)2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33672029

RESUMEN

Exposure to reactive oxygen species can easily result in serious diseases, such as hyperproliferative skin disorders or skin cancer. Herbal extracts are widely used as antioxidant sources in different compositions. The importance of antioxidant therapy in inflammatory conditions has increased. Innovative formulations can be used to improve the effects of these phytopharmacons. The bioactive compounds of Plantago lanceolata (PL) possess different effects, such as anti-inflammatory, antioxidant, and bactericidal pharmacological effects. The objective of this study was to formulate novel liquid crystal (LC) compositions to protect Plantago lanceolata extract from hydrolysis and to improve its effect. Since safety is an important aspect of pharmaceutical formulations, the biological properties of applied excipients and blends were evaluated using assorted in vitro methods on HaCaT cells. According to the antecedent toxicity screening evaluation, three surfactants were selected (Gelucire 44/14, Labrasol, and Lauroglycol 90) for the formulation. The dissolution rate of PL from the PL-LC systems was evaluated using a Franz diffusion chamber apparatus. The antioxidant properties of the PL-LC systems were evaluated with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and malondialdehyde (MDA) assessments. Our results suggest that these compositions use a nontraditional, rapid-permeation pathway for the delivery of drugs, as the applied penetration enhancers reversibly alter the barrier properties of the outer stratum corneum. These excipients can be safe and highly tolerable thus, they could improve the patient's experience and promote adherence.


Asunto(s)
Composición de Medicamentos , Cristales Líquidos/química , Extractos Vegetales/farmacología , Plantago/química , Piel/efectos de los fármacos , Compuestos de Bifenilo/química , Proliferación Celular/efectos de los fármacos , Proliferación Celular/efectos de la radiación , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Impedancia Eléctrica , Depuradores de Radicales Libres/farmacología , Humanos , Peroxidación de Lípido/efectos de los fármacos , Peroxidación de Lípido/efectos de la radiación , Malondialdehído/metabolismo , Permeabilidad , Picratos/química , Piel/efectos de la radiación , Rayos Ultravioleta
9.
Nat Commun ; 12(1): 1569, 2021 03 10.
Artículo en Inglés | MEDLINE | ID: mdl-33692367

RESUMEN

Quantitative criteria to identify proteins as RNA-binding proteins (RBPs) are presently lacking, as are criteria to define RBP target RNAs. Here, we develop an ultraviolet (UV) cross-linking immunoprecipitation (CLIP)-sequencing method, easyCLIP. easyCLIP provides absolute cross-link rates, as well as increased simplicity, efficiency, and capacity to visualize RNA libraries during sequencing library preparation. Measurement of >200 independent cross-link experiments across >35 proteins identifies an RNA cross-link rate threshold that distinguishes RBPs from non-RBPs and defines target RNAs as those with a complex frequency unlikely for a random protein. We apply easyCLIP to the 33 most recurrent cancer mutations across 28 RBPs, finding increased RNA binding per RBP molecule for KHDRBS2 R168C, A1CF E34K and PCBP1 L100P/Q cancer mutations. Quantitating RBP-RNA interactions can thus nominate proteins as RBPs and define the impact of specific disease-associated RBP mutations on RNA association.


Asunto(s)
Proteínas de Unión al ARN/química , ARN/química , Animales , Sitios de Unión , Humanos , Inmunoprecipitación , ARN/metabolismo , ARN/efectos de la radiación , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/efectos de la radiación , Rayos Ultravioleta
10.
Water Sci Technol ; 83(5): 1217-1229, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33724948

RESUMEN

The ultraviolet photochemical degradation process is widely applied in wastewater treatment due to its low cost, high efficiency and sustainability. In this study, a novel rotating flow reactor was developed for UV-initiated photochemical reactions. The reactor was run in a continuous flow mode, and the tangential installation of the inlet and outlet on the annular reactor improved reaction rates. Numerical modelling, which combined solute transport, radiation transfer and photochemical kinetic degradation processes, was conducted to evaluate improvement compared to current reactor designs. Methylene Blue (MB) decomposition efficiency from the modelling results and the experimental data agreed well with each other. The model results showed that a rotational motion of fluid was well developed inside the designed reactor for a wide range of inflow rates; the generation of ·OH radicals significantly depended on UV irradiation dose, and thus the degradation ratio of MB showed a strong correlation with the UV irradiation distribution. In addition, the comprehensive numerical modelling showed promising potential for the simulation of UV/H2O2 processes in rotating flow reactors.


Asunto(s)
Peróxido de Hidrógeno , Purificación del Agua , Cinética , Procesos Fotoquímicos , Rayos Ultravioleta
11.
Appl Opt ; 60(7): 1821-1826, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33690269

RESUMEN

During the present Sars-CoV-2 pandemic, there has been an increase in the development of UVC disinfection systems. Researchers and members of the lighting community shifted their interests to this new field to help develop systems for disinfecting facemasks and other small equipment. In this paper we show that it is possible to use DIALux to simulate the irradiance distribution provided by a lamp emitting in the UVC range. We will compare the results provided by DIALux with those obtained from Zemax OpticStudio in three different scenarios. We compared the minimum, maximum, and mean irradiance at the detection plane. The differences between the two software were less than 12%, 2%, and 6%, respectively. We also compared the contour maps of isoirradiance lines. We conclude that DIALux is well suited for UVC lighting design in the UVC range. We think that this finding will contribute to increasing the design and manufacturing of new UVC disinfection systems needed to fight against the Sars-CoV-2 pandemic.


Asunto(s)
/prevención & control , Desinfección/métodos , Máscaras/virología , Programas Informáticos , Rayos Ultravioleta , /transmisión , Simulación por Computador , Desinfección/instrumentación , Desinfección/estadística & datos numéricos , Diseño de Equipo , Humanos , Modelos Teóricos , Dispositivos Ópticos , Fenómenos Ópticos , Pandemias/prevención & control
12.
Rev Gaucha Enferm ; 42(spe): e20200146, 2021.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-33787720

RESUMEN

OBJECTIVE: To evaluate the protocols on decontamination/reuse of N95 masks available in the literature in times of the Covid-19 pandemic. METHOD: Integrative literature review, in the period from 2010 to 2020, on the databases MEDLINE/PubMed, Science Direct, Cochrane, SAGE journals, Web of Science, Scopus, Embase and Wiley, with the descriptors Masks AND Respiratory protective devices; Mask OR N95 AND Covid-19; N95 AND Respirators; Decontamination AND N95 AND Coronavirus; Facemask OR Pandemic. RESULTS: Twelve studies were included, of which 3 (30.0%) used ultraviolet germicidal irradiation and indicated mask deterioration between 2 and 10 cycles, 4 (40.0%) used hydrogen peroxide vapor, and seal loss varied from 5 to 20 cycles, 4 (33.3%) evaluated the structural integrity of the N95 mask through visual inspection and 6 (54.4%), its filtration efficiency. CONCLUSION: Reuse strategies to overcome a shortage of devices in the face of the pandemic challenge the current concept for good practices in health-product processing.


Asunto(s)
/epidemiología , Descontaminación/métodos , Equipo Reutilizado , Pandemias , Antiinfecciosos Locales , Desinfectantes , Desinfección/métodos , Óxido de Etileno , Filtración/instrumentación , Humanos , Peróxido de Hidrógeno , Rayos Ultravioleta
13.
Molecules ; 26(4)2021 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-33670660

RESUMEN

Water decontamination still remains a major challenge to some developing countries not having centralized wastewater systems. Therefore, this study presents the optimization of photocatalytic degradation of Basic Blue 41 dye in an aqueous medium by an activated carbon (AC)-TiO2 photocatalyst under UV irradiation. The mesoporous AC-TiO2 synthesized by a sonication method was characterized by X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy for crystal phase identification and molecular bond structures, respectively. The efficiency of the AC-TiO2 was evaluated as a function of three input variables viz. catalyst load (2-4 g), reaction time (15-45 min) and pH (6-9) by using Box-Behnken design (BBD) adapted from response surface methodology. Using color and turbidity removal as responses, a 17 run experiment matrix was generated by the BBD to investigate the interaction effects of the three aforementioned input factors. From the results, a reduced quadratic model was generated, which showed good predictability of results agreeable to the experimental data. The analysis of variance (ANOVA), signposted the selected models for color and turbidity, was highly significant (p < 0.05) with coefficients of determination (R2) values of 0.972 and 0.988, respectively. The catalyst load was found as the most significant factor with a high antagonistic impact on the process, whereas the interactive effect of reaction time and pH affected the process positively. At optimal conditions of catalyst load (2.6 g), reaction time (45 min), and pH (6); the desirability of 96% was obtained by a numerical optimization approach representing turbidity removal of 93% and color of 96%.


Asunto(s)
Compuestos Azo/efectos de la radiación , Benzotiazoles/efectos de la radiación , Carbón Orgánico/química , Fotólisis/efectos de la radiación , Titanio/química , Rayos Ultravioleta , Análisis de Varianza , Catálisis/efectos de la radiación , Color , Concentración de Iones de Hidrógeno , Cinética , Nefelometría y Turbidimetría , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X
14.
Food Chem ; 352: 129322, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33690073

RESUMEN

This study explored the effects of brassinolide (BR) soaking, preharvest ultraviolet-B (UV-B) radiation, and their combined treatments on physiological characteristics, chlorophyll fluorescence, and quality of small black bean sprouts during storage. Results indicated that the combined treatments significantly enhanced contents of flavone, free amino acid, and photosynthetic pigment, and activities of phenylalanine ammonia lyase (PAL) and 2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging in sprouts stored for 5 days compared with BR treatment alone. The combined treatments significantly increased total phenols content and PAL activity, and reduced malonaldehyde content in sprouts compared with UV-B radiation alone. The inhibitory effect of BR or UV-B on fluorescence of photosystem II was weakened by their combined treatments. Comprehensive analysis indicated that the combined treatments could be used to maintain postharvest small black bean sprouts with high levels of nutritional ingredients by probably keeping high photosynthetic capacity, PAL activity, and DPPH radical scavenging rate in sprouts.


Asunto(s)
Brasinoesteroides/farmacología , Almacenamiento de Alimentos , Esteroides Heterocíclicos/farmacología , Rayos Ultravioleta , Vigna/efectos de los fármacos , Vigna/efectos de la radiación , Flavonas/metabolismo , Malondialdehído/metabolismo , Fenoles/metabolismo , Fenilanina Amoníaco-Liasa/metabolismo , Vigna/metabolismo
15.
Carbohydr Polym ; 260: 117760, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712122

RESUMEN

A transparent versatile cellulose platform film was prepared from Eucalyptus pulp in this work. Based on such cellulose platform, multifunctional cellulose films with ultraviolet-shielding, photochromism, and strong mechanical strength were fabricated via nucleophilic postmodification strategy by introducing a versatile spiropyran moiety into cellulose molecules. The fabricated cellulose films exhibited super-high transmittance up to 96% and performed notable ultraviolet-shielding capacity at 200-400 nm. Moreover, the photochromic performance of cellulose films with color changes could be clearly observed by the naked eyes, and the fluorescent blue could be excited. Besides, the tensile stress of multi-functional cellulose film was about 80 MPa, which was almost 8 times stronger than that of the commercial polyethylene film at the same thickness. It is noteworthy that these superior performances promote such a cellulose platform to be a versatile precursor for fabricating various multi-functional cellulose used in the fields of out-door coating, transparent packaging, optical screen,etc.


Asunto(s)
Celulosa/química , Benzopiranos/química , Eucalyptus/metabolismo , Indoles/química , Nanocompuestos/química , Nitrocompuestos/química , Espectroscopía Infrarroja por Transformada de Fourier , Protectores Solares/química , Propiedades de Superficie , Resistencia a la Tracción , Rayos Ultravioleta
16.
Water Res ; 196: 117046, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33774353

RESUMEN

Acetylacetone (AA) has proven to be a potent photo-activator for the decolorization of dyes. However, there is very limited information on the quantitative structure-activity relationship (QSAR) and the mechanisms of dye degradation by UV/AA. Herein, the photolysis of 65 aromatic compounds (dyes and dye precursors) was investigated at three pH values (4.0, 6.0, 9.0) by UV/AA and UV/H2O2. The obtained pseudo-first-order photodegradation rate constants (k1) were processed using statistical analysis. The correlation between the k1 values and the number of photons absorbed by AA, together with the observed pH effect, suggested that the protonated enol structure of AA plays a crucial role in the photodecolorization of dyes. According to quantum chemical computation, photo-induced direct electron transfer between the excited state of AA and the dye was the main mechanism in the UV/AA process. QSAR models demonstrated that the molecular size and stability were the key factors that determined the efficiency of UV/H2O2 for dye degradation. Statistically, the UV/AA process was target-selective and suffered less from the inner filter effect, which made it more effective than the UV/H2O2 process for dye degradation. The selectivity of the UV/AA process was mainly embodied in the substituent effects: dyes with hydroxyl groups in conjugated systems decomposed faster than those with nitro-substitution or ortho-substituted sulfonate groups. The results can be used for the selection of appropriate photochemical approaches for the treatment of dye-contaminated water.


Asunto(s)
Contaminantes Ambientales , Contaminantes Químicos del Agua , Peróxido de Hidrógeno , Oxidación-Reducción , Pentanonas , Fotólisis , Rayos Ultravioleta , Contaminantes Químicos del Agua/análisis
17.
Environ Pollut ; 277: 116797, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33647807

RESUMEN

This study is focused on oxytetracycline (OTC) degradation by direct photolysis (UV-C) and photobased advanced oxidation processes (AOPs) (UV-C/H2O2 and UV-C/S2O82-). OTC degradation pathways were revealed by LC-MS/MS and GC-MS/MS analyses. The evolution/degradation profiles of 12 detected byproducts were correlated with changes in biodegradability and toxicity toward Vibrio fischeri recorded during the treatment. Both photobased AOPs yielded higher OTC degradation and mineralization rates than direct photolysis. The OTC degradation pathway was found to be rather specific regarding the main reactive species (HO• or SO4•-)/mechanism, yielding different patterns in toxicity changes, while biodegradability profiles were less affected. Biodegradability was correlated with the observed degradation and mineralization kinetics. The recorded toxicity changes indicate that byproducts formed by initial OTC degradation are more toxic than the parent pollutant. The prolonged treatment resulted in the formation of byproducts that contributed to a decrease in toxicity and an increase in biodegradability, as particularly emphasized in the case of UV-C/S2O82-.


Asunto(s)
Oxitetraciclina , Contaminantes Químicos del Agua , Purificación del Agua , Cromatografía Liquida , Peróxido de Hidrógeno , Cinética , Oxidación-Reducción , Oxitetraciclina/análisis , Oxitetraciclina/toxicidad , Fotólisis , Espectrometría de Masas en Tándem , Rayos Ultravioleta , Agua , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
18.
J Photochem Photobiol B ; 217: 112168, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33714723

RESUMEN

Worldwide shortages of personal protective equipment during COVID-19 pandemic has forced the implementation of methods for decontaminating face piece respirators such as N95 respirators. The use of UV irradiation to reduce bioburden of used respirators attracts attention, making proper testing protocols of uttermost importance. Currently artificial saliva is used but its comparison to human saliva from the UV disinfection perspective is lacking. Here we characterize UV spectra of human and artificial saliva, both fresh and after settling, to test for possible interference for UV-based disinfection. ASTM 2720 artificial saliva recipe (with either porcine or bovine mucin) showed many discrepancies from average (N = 18) human saliva, with different mucins demonstrating very different UV absorbance spectra, resulting in very different UV transmittance at different wavelength. Reducing porcine mucin concentration from 3 to 1.7 g/L brought UVA254 in the artificial saliva to that of average human saliva (although not for other wavelengths), allowing 254 nm disinfection experiments. Phosphate saline and modified artificial saliva were spiked with 8.6 log CFU/ml B. subtilis spores (ATCC 6633) and irradiated at dose of up to 100 mJ/cm2, resulting in 5.9 log inactivation for a saline suspension, and 2.8 and 1.1 log inactivation for ASTM-no mucin and ASTM-1.7 g/L porcine mucin 2 µL dried droplets, respectively. UVC irradiation of spores dried in human saliva resulted in 2.3 and 1.5 log inactivation, depending on the size of the droplets (2 vs 10 µL, respectively) dried on a glass surface. Our results suggest that in the presence of the current standard dried artificial saliva it is unlikely that UVC can achieve 6 log inactivation of B. subtilis spores using a realistic UV dose (e.g. less than 2 J/cm2) and the ATSM saliva recipe should be revised for UV decontamination studies.


Asunto(s)
Desinfección/métodos , Saliva/química , Saliva/efectos de la radiación , Animales , Bacillus subtilis/efectos de la radiación , Canadá , Bovinos , Descontaminación/métodos , Femenino , Humanos , Israel , Masculino , Mucinas/química , Saliva/microbiología , Manejo de Especímenes/métodos , Espectrofotometría Ultravioleta , Esporas Bacterianas/efectos de la radiación , Rayos Ultravioleta
19.
Water Res ; 195: 116940, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33735627

RESUMEN

Organic micropollutants (MPs) are increasingly detected in water resources, which can be a concern for human health and the aquatic environment. Ultraviolet (UV) radiation based advanced oxidation processes (AOP) such as low-pressure mercury vapor arc lamp UV/H2O2 can be applied to abate these MPs. During UV/H2O2 treatment, MPs are abated primarily by photolysis and reactions with hydroxyl radicals (•OH), which are produced in situ from H2O2 photolysis. Here, a model is presented that calculates the applied UV fluence (Hcalc) and the •OH exposure (CT•OH,calc) from the abatement of two selected MPs, which act as internal probe compounds. Quantification of the UV fluence and hydroxyl radical exposure was generally accurate when a UV susceptible and a UV resistant probe compound were selected, and both were abated at least by 50 %, e.g., iopamidol and 5-methyl-1H-benzotriazole. Based on these key parameters a model was developed to predict the abatement of other MPs. The prediction of abatement was verified in various waters (sand filtrates of rivers Rhine and Wiese, and a tertiary wastewater effluent) and at different scales (laboratory experiments, pilot plant). The accuracy to predict the abatement of other MPs was typically within ±20 % of the respective measured abatement. The model was further assessed for its ability to estimate unknown rate constants for direct photolysis (kUV,MP) and reactions with •OH (k•OH,MP). In most cases, the estimated rate constants agreed well with published values, considering the uncertainty of kinetic data determined in laboratory experiments. A sensitivity analysis revealed that in typical water treatment applications, the precision of kinetic parameters (kUV,MP for UV susceptible and k•OH,MP for UV resistant probe compounds) have the strongest impact on the model's accuracy.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Humanos , Peróxido de Hidrógeno , Radical Hidroxilo , Oxidación-Reducción , Fotólisis , Rayos Ultravioleta
20.
Sci Rep ; 11(1): 6260, 2021 03 18.
Artículo en Inglés | MEDLINE | ID: mdl-33737536

RESUMEN

The potential virucidal effects of UV-C irradiation on SARS-CoV-2 were experimentally evaluated for different illumination doses and virus concentrations (1000, 5, 0.05 MOI). At a virus density comparable to that observed in SARS-CoV-2 infection, an UV-C dose of just 3.7 mJ/cm2 was sufficient to achieve a more than 3-log inactivation without any sign of viral replication. Moreover, a complete inactivation at all viral concentrations was observed with 16.9 mJ/cm2. These results could explain the epidemiological trends of COVID-19 and are important for the development of novel sterilizing methods to contain SARS-CoV-2 infection.


Asunto(s)
/efectos de la radiación , Rayos Ultravioleta , Inactivación de Virus , Replicación Viral/efectos de la radiación
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