Artificial Lamps Research Articles

Discussion Abounds on the Potential Carcinogenic Risks Associated With the Use of UV Curing Lamps for Permanent Nail Polish

BackgroundControversy has recently broken out over the potential carcinogenic risk associated with exposure to UV lamps for permanent nail polish. The new LED-based polymerization devices, and their potential biological effect has not been analyzed to this date. ObjectiveTo evaluate the emission power and its potential biological effects on the skin of 2 types of UV LED and fluorescent curing lamps under normal use conditions compared to doses of sunlight exposure. Material and methodsThe emission spectrum (290nm to 450nm) of curing lamps and the Sun at noon on an average summer day in mid-latitude Spain was analyzed. The effective biological irradiance potential for erythema, non-melanoma skin cancer, DNA damage, photoimmunosuppression and permanent pigmentation was also characterized. ResultsThe high-energy UVA-visible irradiance emitted by these devices was similar to the one coming from the Sun in that spectral range while the effective biological doses were lower or similar to those also coming from the Sun. The total UV and high-energy visible dose per manicure session corresponded to that obtained from 3.5min to 6min exposures to the Sun at noon in the summer days at our latitudes. ConclusionsThe exposure times and doses received with the common use of artificial lamp nail drying correspond to sunlight exposures of 3min to 5min in the central hours of the day. This represents a very low carcinogenic potential compared to sunlight exposure, although similar regarding immunosuppressive potential. Photoprotective measures would further minimize the risks.

Controversias sobre los riesgos procarcinogénicos asociados al uso de lámparas ultravioleta polimerizadoras para el esmaltado permanente de uñas

BackgroundControversy has recently broken out over the potential carcinogenic risk associated with exposure to UV lamps for permanent nail polish. The new LED-based polymerization devices, and their potential biological effect has not been analyzed to this date. ObjectiveTo evaluate the emission power and its potential biological effects on the skin of 2 types of UV LED and fluorescent curing lamps under normal use conditions compared to doses of sunlight exposure. Material and methodsThe emission spectrum (290nm to 450nm) of curing lamps and the Sun at noon on an average summer day in mid-latitude Spain was analyzed. The effective biological irradiance potential for erythema, non-melanoma skin cancer, DNA damage, photoimmunosuppression and permanent pigmentation was also characterized. ResultsThe high-energy UVA-visible irradiance emitted by these devices was similar to the one coming from the Sun in that spectral range while the effective biological doses were lower or similar to those also coming from the Sun. The total UV and high-energy visible dose per manicure session corresponded to that obtained from 3.5min to 6min exposures to the Sun at noon in the summer days at our latitudes. ConclusionsThe exposure times and doses received with the common use of artificial lamp nail drying correspond to sunlight exposures of 3min to 5min in the central hours of the day. This represents a very low carcinogenic potential compared to sunlight exposure, although similar regarding immunosuppressive potential. Photoprotective measures would further minimize the risks.

Development of a new rotating photocatalytic reactor for the degradation of hazardous pollutants

Abstract The aim of this study was to develop a new rotating photocatalytic reactor operating in recirculation mode with light sources placed outside the photoreactor vessel. The photoreactor with cylindrical geometry was equipped with four artificial lamps used to simulate solar irradiation (2.4% UVB and 12% UVA; 300–700 nm). The photocatalyst was immobilized on abrasive material used as a support and placed on the central (inner) photoreactor tube, which was connected to a power-driven shaft that allowed rotation at a desired speed. A suitable modification of the commercial TiO2 P25 photocatalyst was carried out to reduce its band gap energy and electron-hole recombination and to extend the visible light response range of TiO2. The main task of this research was to apply the basic principles of process intensification methodology, i.e. to explore the influence of rotational hydrodynamics, which allows good access of reactants to the photocatalyst surface, good irradiation of the photocatalytic surface and reduction of mass transfer resistance, leading to increased process efficiency. The homemade photoreactor was used for the photocatalytic degradation of one of the major types of neonicotinoid insecticides, acetamiprid. The influence of various working conditions, such as initial solution pH, rotation speed, recirculation flow rate and initial concentration of acetamiprid on the photocatalytic degradation process was investigated. The optimum degradation conditions were found at a recirculation flow rate of 200 cm3 min−1 and a rotation speed of 200 rpm, indicating that the mass transfer process strongly contributes to the photocatalytic degradation rate at the conditions used in this study. The results obtained during the photocatalytic degradation of acetamiprid in a rotating photoreactor were compared with those obtained under similar operating conditions in a flat-plate photoreactor, and the corresponding conclusions were drawn based on the performed kinetic analysis.

COVID-19 and Its Derivatives- A relation with light for health

Light now has many applications in life and plays a vital role in therapeutic and protective fields. In the recent era, many light sources are considered for prevention, sterilization, and curing, especially with artificial lamps. Since the coronavirus pandemic appeared in 2019, the world has been interested in sterilization by light rays from a physical and applied point of view. In this work, the authors focus on definite spectral bands and their direct effects on the current COVID-19 pandemic for a prevention spreading purpose. According to the light use results, until now, the most useful method for decontamination against COVID-19 is ultraviolet C. The other spectral bands like UVA, UVB, and violet-blue show that they have a more negligible effect on the deactivation of the COVID-19 virus. The UVA and UVB help increase vitamin D in the human body, reflecting positively on the immunity system and increasing the recovery rate. The violet-blue band is helpful in decontamination against bacteria microorganisms. As for the IR band, the studies are still recent, and until now, there is no recommendation to use this band in sterilization against this pandemic. Studies continued on UV utilization because the world urgently needs industrial and domestic disinfection systems and sterilization. The other bands have another substantial practical effect on health improvement so any people can survive and overcome different diseases.

Layered MoS2 for photocatalytic dye degradation

In the present study, Lawesson’s reagent (LR) is used as a sulfur source for the formation of layered MoS2 semiconductor nanostructures. MoS2 layers are prepared using 15 hr. hydrothermal reaction method at 120 °C. X-ray diffraction (XRD), UV–visible (UV), BET analysis and FESEM micrographs of 15 hr. reaction time. After synthesis and characterization, MoS2 nanostructures were checked for its photocatalytic behavior. For photocatalytic study two complex organic dyes (Methylene blue and Crystal violet) degradation experiments were carried out under natural sunlight and in UV lamp. MoS2 degrades almost 71% and 57% of MoS2-MB and MoS2-CV, respectively within 90 min. of irradiation time in natural sunlight. Also, photocatalytic dye degradation found almost 82% and 73% of MoS2-MB and MoS2-CV, respectively within 90 min. of irradiation time in lab under artificial lamp. As compared to natural sunlight study the rate of dye degradation found more in UV lamp experiments for both the dyes.

Enhancement of algae ponds for rural domestic sewage treatment by prolonging daylight using artificial lamps

Algal ponds (APs) are widely used as treatment facilities for domestic sewage in sparsely populated rural areas. However, few AP studies have focused on daylight length to enhance pollutants removal. In this study, four algae ponds were set up, daylight was prolonged by 0, 2, 4, and 6 h with an illuminating intensity of 3000 lx. The highest removal efficiencies of total nitrogen, ammonium, and total phosphorus were 37.36%, 41.20%, and 21.56% due to the highest microbial abundance under optimum conditions (2 h PD), respectively. Excessive PD (4 h and 6 h) could inhibit the removal abilities. PD also increased the maximum relative electron transport rate of algae, leading to an increase in the photosynthetic capacity of APs. Meanwhile, the high microbial abundance indicates that chemoheterotrophic bacteria are the main influencing factor for the removal of nitrogen and phosphorus by the APs. Moreover, the system with PD using artificial lamps was proven to be feasible for engineering applications and potentially utilized in rural domestic wastewater treatment.

Growth performance of ICCRI 06 H cocoa seedling in response to different microclimate and soil moisture conditions

Climate and environmental factors play an important role for cocoa (Theobroma cacao L.) optimal growth and production. This study aims to evaluate growth performance and stomatal characteristics of cocoa seedling in response to microclimate, i.e. temperature, relative humidity, light intensity and soil moisture condition. The cacao variety of ICCRI 06 H was used for greenhouse experiment arranged by a completely randomized design with three replications. The first factor was evapotranspiration (ETa) i.e. ETa-1 100% (control), ETa-2 50% (moderate stress), and ETa-3 25% (severe stress). The second factor was microclimate condition defined by its location in the greenhouse, i.e. inside the glass box (IB) and outside the glass box (OB). IB microclimate conditions were modified through the installation of 50-Watt LED artificial lamps. Our seven weeks observations demonstrated the specific microclimate condition created both in IB and OB. An insignificant effect of different soil moisture level to cocoa seedling growth was evidenced. Conversely, microclimate condition shows a significant effects especially the plant height and stem diameter. The multiple regression analysis suggests the presence of connection between microclimate and crop growth, i.e. plant height, stem diameter, and number of young cocoa leaves in IB. The stomatal characteristics indicate the more stressed condition created outside the box.

Accurate surface ultraviolet radiation forecasting for clinical applications with deep neural network

Exposure to appropriate doses of UV radiation provides enormously health and medical treatment benefits including psoriasis. Typical hospital-based phototherapy cabinets contain a bunch of artificial lamps, either broad-band (main emission spectrum 280–360 nm, maximum 320 nm), or narrow-band UV B irradiation (main emission spectrum 310–315 nm, maximum 311 nm). For patients who cannot access phototherapy centers, sunbathing, or heliotherapy, can be a safe and effective treatment alternative. However, as sunlight contains the full range of UV radiation (290–400 nm), careful sunbathing supervised by photodermatologist based on accurate UV radiation forecast is vital to minimize potential adverse effects. Here, using 10-year UV radiation data collected at Nakhon Pathom, Thailand, we developed a deep learning model for UV radiation prediction which achieves around 10% error for 24-h forecast and 13–16% error for 7-day up to 4-week forecast. Our approach can be extended to UV data from different geographical regions as well as various biological action spectra. This will become one of the key tools for developing national heliotherapy protocol in Thailand. Our model has been made available at https://github.com/cmb-chula/SurfUVNet.

Hepato- and hemato-protective properties of α-ketoglutarate under the combined effect of water-immobilization and emotional stress

This article presents the results of the combined effect of water-immobilization and emotional stress on haematological and morphological parameters of blood and liver status of rats in conditions of correction of the disorders using by α-ketoglutarate. Experimental combined stress was induced by the interchangeable effect of dry immobilization and immersion in water for 3 days under constant illumination using an artificial lighting lamp of 1,000 lux., thus achieving a combined effect of stress. Physiological adaptation and administration of 5 mg/kg of body weight of α-ketoglutarate lasted 14 days after stress induction. Haematological parameters were determined using the Automated Veterinary Hematology Analyzer PCE 90 Vet (High Technology Inc., USA), while biochemical parameters of the liver state were determined by spectrophotometric and colourimetric methods. The obtained results showed an increase in hemolysis, which was determined by a decrease in the number of erythrocytes and haemoglobin concentration in the blood of rats under the effect of the stress factors studied. A negative consequence of strengthening of hemolysis is the development of hypoxia in the liver, which causes the slowing of metabolic processes in its cells. As a result, there is an accumulation of partially oxidized products: lactate and pyruvate, increased formation of TBA-active products, and oxidative modification of proteins. During the 14 days of physiological adaptation after stress, the main indicators of blood and liver status of the rats were partially restored. A stronger recovery of redox status and improvement of the physiological state of the liver and, hence, haematological parameters, were noted for rats that received α-ketoglutarate for 14 days after stress. The revealed general positive trend indicates the stimulation of adaptation processes and the overall functioning of the antioxidant system of the liver of rats in the use of α-ketoglutarate against the background of the combined effects of water-immobilization and emotional stress.

Genoprotective Effect of Phyllanthus orbicularis Extract Against UVA, UVB, and Solar Radiation.

One approach to protect the human skin against harmful effects of solar ultraviolet (UV) radiation was to use natural products as photoprotectors. In this work, the extract from specie Phyllanthus orbicularis K was evaluated as a protective agent against the photodamage by UVB, UVA artificial lamps, and environmental sunlight exposure. The plasmid DNA solutions were exposed to radiations using the DNA dosimeter system in the presence of plant extract. The DNArepair enzymes, Escherichia coli Formamidopyrimidine-DNA glycosylase (Fpg) and T4 bacteriophage endonuclease V (T4-endo V), were employed to discriminate oxidized DNA damage and cyclobutane pyrimidine dimers (CPD), respectively. The supercoiled and relaxed forms of DNA were separated through electrophoretic migration in agarose gels. These DNA forms were quantified to determine strand break, representing the types of lesion levels. The results showed that, in the presence of P.orbicularis extract, the CPD and oxidative damage were reduced in irradiated DNA samples. The photoprotective effect of extract was more evident for UVB and sunlight radiation than for UVA. This work documented the UV absorbing properties of P.orbicularis aqueous extract and opened up new vistas in its characterization as protective agent against DNA damage induced by environmental sunlight radiation.

The Effect of Graphene/TIO<sub>2</sub> Nanomaterials on Photocatalytic Performance for Industrial Wastewater Treatment

The aim of the present work is to combine TiO2/Graphene to increase photo-catalytic activity and obtain efficient removal of direct red 23 azo dye without difficult synthesis. Many operating variables which affect the process and some design aspects were studied. Reactor geometry is the main design parameter where slurry rectangular reactor and bubble column were compared with respect to hydrodynamic regimes, overall degradation efficiency and applicability in industrial scale. The removal rate was found to increase with increase in TiO2 concentration, approaching a limiting value at catalyst loads of 3g/L. For rectangular reactor only 0.005g/L of rGO able to enhance the activity of photo-catalysis. However, the optimum concentration of rGO is decreased in the bubble column reactor to be 0.001g/L. In both reactor systems, photocatalytic activity increase significantly by decreasing wavelength of the irradiated lamp from 365 nm to 254 nm. Also, results show the ability of bubble column reactor to treat high concentrations of dye up to 200 ppm. That makes it suitable to be integrated with biological system to convert non-biodegradable contaminates into biodegradable organics. That reduces the operating cost of the process and makes it more applicable in industrial scale. Rectangular reactor has the ability to be modified to use sunlight instead of artificial lamps because of high surface exposed to sunlight. In general the performance of bubble column reactor was better than rectangular reactor because it has excellent mass transfer characteristics, which enhance the efficiency of the process.

Effect of Artificial Light Conditions on Local and Systemic Resistance Response of Tobacco to TMV Infection

Systemic acquired resistance (SAR) is effectively inducible in greenhouse and certain artificial light sources cause non-optimal growth of tobacco plants. Therefore, the morphological characteristics, local and systemic resistance response of N. tabacum cv. ‘Xanthi’ nc plants (harbouring NN resistance genes) to tobacco mosaic virus (TMV) infection under three artificial light sources with different spectral distribution were compared with greenhouse conditions. Statistical analysis of data was carried out by R package (R Core Team, 2015). Generally, artificial light sources (especially fluorescent tube, and halogen lamp) decreased the local resistance response and caused substantial morphological and developmental differences as compared to greenhouse conditions when plants were kept during their entire life (lifelong experimental regime) under these conditions. On the contrary, no or much less differences were found when plants were transferred from greenhouse to artificial light sources only at six leaf stage (short experimental regime). While induction of systemic acquired resistance (SAR) frequently decreased TMV lesion size by about 50-60% under greenhouse conditions, two of the three artificial light sources, fluorescent tube and halogen lamp were substantially and significantly less effective under short experimental regime conditions (25-35%). A metal halide light source with similarity to sunshine’s spectral distribution, however, partially mimicked the effect of greenhouse conditions indicating the importance of light spectrum among other factors in SAR induction and prevention of distorted growth of plants. Consequently, the optimization of the effect of artificial light sources is an important factor in experimental design studying signal transduction and biochemistry of SAR.

Contrasting Responses of Marine and Freshwater Photosynthetic Organisms to UVB Radiation: A Meta-Analysis

Ultraviolet-B (UVB) radiation is a global stressor that has profound impacts on freshwater and marine ecosystems. However, an analysis of the patterns of sensitivity to UVB radiation across aquatic photosynthetic organisms has not yet been published. Here, we performed a meta-analysis on results reported in 214 studies compiled from the published literature to quantify and compare the magnitude of responses of aquatic photosynthetic organisms to changes in UVB radiation. The meta-analysis was conducted on observations of marine (n = 893) and freshwater macroalgae (n = 126) and of marine (n = 1087) and freshwater (n = 2889) microalgae (total n = 4995). Most of these studies (85%) analysed the performance of organisms exposed to natural solar radiation when UVB was partially or totally reduced compared with the organismal performance under the full solar radiation spectrum, whereas the remaining 15% of the studies examined the responses of organisms to elevated UVB radiation mostly using artificial lamps. We found that marine photosynthetic organisms tend to be more sensitive than freshwater photosynthetic organisms to UVB radiation; responses to either decreased or increased UVB radiation vary among taxa; the mortality rate is the most sensitive of the trait responses to elevated UVB radiation, followed by changes in cellular and molecular traits; the sensitivity of microalgae to UVB radiation is dependent on size, with small-celled microalgae more sensitive than large-celled microalgae to UVB radiation. Thick macroalgae morphotypes were the less sensitive to UVB, but this effect could not be separated from phylogenetic differences. The high sensitivity of marine species, particularly the smallest photosynthetic organisms, to increased UVB radiation suggests that the oligotrophic ocean, a habitat comprising 70 % of the world’s oceans with high UVB penetration and dominated by picoautotrophs, is extremely vulnerable to changes in UVB radiation.

Experimental study of luminous flux flicker coefficient of artificial light sources

A phenomenon of luminous flux flicker of artificial light lamps of general and industrial use is analyzed in the article. The analysis shows that luminous flux flicker adversely affects the human condition. However, most manufacturers of lamps not knowingly induce flicker performance for their products. Difficult professional devices are used to check the availability of flicker and measure its depth in the market of electronic devices. They are virtually inaccessible to the public taking into account the producing countries and pricing. On this basis, relatively simple device for analyzing the luminous flux flicker is proposed. It is based on a converter of optical radiation – photodiode and detector-oscilloscope. With the developed device, studies of the most common artificial light lamps that are present in the domestic market were conducted. The resulting waveforms of changes for luminous flux in time were obtained and flicker coefficients were calculated. Studies were found that certain examples of widely used lamps have unacceptable level of luminous flux flicker. Thus it is shown that it can’t trust the manufacturer advertising when designing of high-quality lighting systems, and should, if possible, check for flicker.

Novel Biomimatic Synthesis of ZnO Nanorods Using Egg White (Albumen) and Their Antibacterial Studies.

Zinc oxide (ZnO) is well-recognized as a biocompatible multifunctional material with outstanding properties as well as low toxicity and biodegradability. In this work, a simple and versatile technique was developed to prepare highly crystalline ZnO nanorods by introducing egg white to a bio-inspired approach. X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern results indicated that the ZnO nanorods have single phase nature with the wurtzite structure. Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) results showed the nanometer dimension of the nanorods. Raman, FTIR, and TGA/DTA analyses revealed the formation of wurtzite ZnO. The antibacterial properties of ZnO nanorods were investigated using both Gram-positive and Gram-negative microorganisms. These studies demonstrate that ZnO nanorods have a wide range of antibacterial activities toward various microorganisms that are commonly found in environmental settings. Survival ratio of bacteria decreased with increasing powder concentration, i.e., increase in antibacterial activity. The antibacterial activity of the ZnO nanorods toward Pseudomonas aeruginosa was stronger than that of Escherichia coli and Staphylococcus aureus. Surprisingly, the antibacterial activity did not require specific UV activation using artificial lamps, rather activation was achieved under ambient lighting conditions. Overall, the experimental results suggest that ZnO nanorods could be developed as antibacterial agents against a wide range of microorganisms to control and prevent the spreading and persistence of bacterial infections. This research introduces a new concept to synthesize ZnO nanorods by using egg white as a biological template for various applications including food science, animal science, biochemistry, microbiology and medicine.

Novel Methodology for Rapid Detection of KRAS Mutation Using PNA-LNA Mediated Loop-Mediated Isothermal Amplification.

Detecting point mutation of human cancer cells quickly and accurately is gaining in importance for pathological diagnosis and choice of therapeutic approach. In the present study, we present novel methodology, peptide nucleic acid—locked nucleic acid mediated loop-mediated isothermal amplification (PNA-LNA mediated LAMP), for rapid detection of KRAS mutation using advantages of both artificial DNA and LAMP. PNA-LNA mediated LAMP reactions occurred under isothermal temperature conditions of with 4 primary primers set for the target regions on the KRAS gene, clamping PNA probe that was complimentary to the wild type sequence and LNA primers complementary to the mutated sequences. PNA-LNA mediated LAMP was applied for cDNA from 4 kinds of pancreatic carcinoma cell lines with or without KRAS point mutation. The amplified DNA products were verified by naked-eye as well as a real-time PCR equipment. By PNA-LNA mediated LAMP, amplification of wild type KRAS DNA was blocked by clamping PNA probe, whereas, mutant type KRAS DNA was significantly amplified within 50 min. Mutant alleles could be detected in samples which diluted until 0.1% of mutant-to-wild type ratio. On the other hand, mutant alleles could be reproducibly with a mutant-to-wild type ratio of 30% by direct sequencing and of 1% by PNA-clamping PCR. The limit of detection (LOD) of PNA-LNA mediated LAMP was much lower than the other conventional methods. Competition of LNA clamping primers complementary to two different subtypes (G12D and G12V) of mutant KRAS gene indicated different amplification time depend on subtypes of mutant cDNA. PNA-LNA mediated LAMP is a simple, rapid, specific and sensitive methodology for the detection of KRAS mutation.

Research of night light effects on colorimetric characteristics of image perceived by the pilot in an aircraft cockpit

Subject of Research. The influence of radiation spectra from the source of artificial night light on colorimetric characteristics of image perceived by the pilot in the aircraft cockpit has been studied. The image is displayed on the LCD screen of multifunctional color indication equipment unit. Night illumination of the cockpit is performed with the use of artificial lamps of red, green, blue and, rarely, white light. Method. Any given color to be displayed on the screen is perceived by an observer differently with presence and absence of external illumination. When external light of white color is used, perceived color depends upon color temperature of the light source; if illumination source has any arbitrary spectral characteristics, then perceivable color depends upon whole spectral content of the used source. The color, perceived by an observer, is formed as the mixture of the color displayed on the screen (image element color) with the color presented by diffuse reflection of external illumination source from the surface of the screen. The brightness of both colors is added. Mathematical expressions, that define calculation rule for chromaticity coordinates of color perceived by an observer, are based on the Grassmann’s law of additive color mixing. Quantitative analysis of the effect, caused by radiation spectra from an external source of artificial light on color gamut area, corresponding to image, perceived by an observer, has been performed through simulation in MathCad 15.0. Main Results. It was shown, that the color palette of on-board indication equipment, obtained on automated working place for any preset source of external illumination of fluorescent spectrum, corresponding to white light, is not usable correctly in the aircraft night flight mode. An observer loses ability to perceive properly saturated primary colors of red and blue in the case of green-blue light source of external illumination; and the same issue occurs with green and blue for red light source. Using of sources with high illumination level of “warm” white color causes significant shift of the colors perceived by an observer, from the area of saturated blue and green colors in the direction towards the white point defined by illumination source. Using the sources with high illumination level of smooth white color and also with the white color, which white point coordinates coincide with the white point coordinates the color gamut triangle of the tested screen, lead to offset of colors, perceived by an observer, equally for each primary color (red, green, blue) and yellow, cyan and magenta as well. And finally, dealing with sources with high illumination level of “cold” white color, significant offset of colors, perceived by an observer, occurs; those seeming colors are drifting from the area of saturated red and green colors in the direction towards the white point defined by illumination source. Practical Relevance. The results are usable by developers of indication equipment and the manufacturers of LCD panels for colorimetric calculations with account of an influence of external illumination with various spectral content on the screen.v

Comparison of Processes for the Degradation of Trans-Cinnamic Acid: Anodic Oxidation, Electro-Fenton and Photoelectro-Fenton

INTRODUCTION Olive mill wastes worsen environmental problems in Mediterranean countries. These wastewaters contain phenolic compounds used as fragrances and artificial flavours and other compounds such as trans-cinnamic acid. The electrochemical techniques, especially the electrochemical advanced oxidation processes (EAOPs), are applied in many fields including the wastewater treatment. EAOPs are based on the in situ electrochemical generation of the hydroxyl radical (●OH), which has so high oxidizing power that it is able to yield dehydrogenated or hydroxilated derivatives that can be oxidized up to their complete mineralization. EXPERIMENTAL In this work, the degradation of trans-cinnamic acid was studied by means of various EAOPs. Solutions of 100 mL of this compound in 0.05 M Na2SO4 of pH 3.0 were comparatively treated by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF) using a stirred tank reactor equipped with a 3 cm2 boron-doped diamond (BDD) anode and a 3 cm2 carbon-polytetrafluoroethylene air-diffusion cathode. In AO-H2O2, the acid and its intermediates were destroyed by ●OH formed at the BDD surface, whereas in EF the mineralization rate was enhanced by ●OH generated in the bulk from Fenton’s reaction between cathodically generated H2O2 and 0.5 mM Fe2+ added at the beginning of the experiment. In the case of PEF, the degradation process can be significantly enhanced under the photocatalytic action of UVA radiation provided by a 6 W artificial lamp. For each method, the influence of current density and trans-cinnamic acid content on TOC decay was examined. The results revealed that the PEF process was always the most efficient treatment, allowing an almost total mineralization of a 100 mg L-1 TOC solution of trans-cinnamic acid after 180 min of electrolysis at 33.3 mA cm-2. Generated short-chain aliphatic carboxylic acids as oxalic, acetic and fumaric in the above treatments were identified and quantified by ion-exclusion HPLC. RESULTS For all the EAOPs tested, TOC was gradually reduced at prolonged electrolysis. The oxidation ability increased in the sequence AO-H2O2 < EF < PEF. For each method, the mineralization was enhanced with increasing current density. PEF became the most potent method, yielding 98% mineralization after 180 min at 33.3 and 66.7 mA cm-2, which showed that UVA light was a powerful tool. TOC removal increased at a higher initial trans-cinnamic acid concentration, especially in the EF and PEF assays, thereby making the process much more efficient. HPLC chromatograms of electrolyzed solutions exhibited well-defined peaks related to oxalic (t r = 6.96 min), acetic (t r = 15.1 min) and fumaric (t r = 15.6 min) acids. The two latter acids are formed from the cleavage of the benzene ring of trans-cinnamic acid, being oxidized to oxalic acid that is directly and completely mineralized to CO2in 240 min by PEF. DISCUSSION Trans-cinnamic acid solutions can be decontaminated at pH 3 and 25 °C using a BDD/air-diffusion cell. This is due to the oxidation with ●OH formed from water oxidation at the BDD surface in AO-H2O2, the additional destruction with ●OH produced in the bulk from Fenton’s reaction between generated H2O2 and added Fe2+in EF, and the synergistic action of photolysis of Fe(III)-carboxylate complexes under UVA irradiation in PEF. The mineralization rate of trans-cinnamic acid increases in the order AO-H2O2 < EF < PEF under the same experimental conditions due to the larger production of ●OH and the action of UVA light. For each EAOP, higher mineralization rate was found at higher current density as a result of the higher generation of ●OH at the BDD surface and in the bulk, but the mineralization current efficiency decreased because of the enhancement of parasite reaction of ●OH. An increase in trans-cinnamic acid concentration caused a higher TOC removal with superior current efficiency due to the minimization of parasite reactions of ●OH by the presence of more organic matter. The destruction of the parent molecule and its intermediates yielded final short-chain carboxylic acids such as fumaric, acetic and oxalic. The latter was the most persistent but its Fe(III) complexes could be rapidly photodecomposed in PEF. The PEF process was the most potent EAOP giving rise to an almost total mineralization of solutions with 100 mg L-1 TOC of trans-cinnamic acid after 180 min at 33.3 mA cm-2. The EAOPs tested demonstrated their feasibility to decontaminate water containing trans-cinnamic acid, opening the door to develop more effective technologies for the treatment of olive mill wastewaters. ACKNOWLEDGEMENTS The authors are grateful to MINECO (Spain) for financial support from project CTQ2013-48897-C2-1-R, co-financed with FEDER funds. The scholarship given to N.E Flores from SENECYT (Ecuador) is also acknowledged.

Update on ultraviolet A and B radiation generated by the sun and artificial lamps and their effects on skin.

Solar radiation, especially ultraviolet A (UVA) and ultraviolet B (UVB), can cause damage to the human body, and exposure to the radiation may vary according to the geographical location, time of year and other factors. The effects of UVA and UVB radiation on organisms range from erythema formation, through tanning and reduced synthesis of macromolecules such as collagen and elastin, to carcinogenic DNA mutations. Some studies suggest that, in addition to the radiation emitted by the sun, artificial sources of radiation, such as commercial lamps, can also generate small amounts of UVA and UVB radiation. Depending on the source intensity and on the distance from the source, this radiation can be harmful to photosensitive individuals. In healthy subjects, the evidence on the danger of this radiation is still far from conclusive.

Gaseous products and secondary organic aerosol formation during long term oxidation of isoprene and methacrolein

Abstract. First- and higher order-generation products formed from the oxidation of isoprene and methacrolein with OH radicals in the presence of NOx have been studied in a simulation chamber. Significant oxidation rates have been maintained for up to 7 h, allowing the study of highly oxidized products. Gas-phase product distribution and yields were obtained, and show good agreement with previous studies. Secondary organic aerosol (SOA) formation has also been investigated. SOA mass yields from previous studies show large discrepancies. The mass yields obtained here were consistent with the lowest values found in the literature, and more specifically in agreement with studies carried out with natural light or artificial lamps with emission similar to the solar spectrum. Differences in light source are therefore proposed to explain partially the discrepancies observed between different studies in the literature for both isoprene- and methacrolein-SOA mass yields. There is a high degree of similarity between the SOA mass spectra from isoprene and methacrolein photooxidation, thus strengthening the importance of the role of methacrolein in SOA formation from isoprene photooxidation under our experimental conditions (i.e., presence of NOx and long term oxidation). According to our results, SOA mass yields from both isoprene and methacrolein in the atmosphere could be lower than suggested by most of the current chamber studies.