Combined Ultraviolet Radiation Research Articles

UV Light Causes Structural Changes in Microplastics Exposed in Bio-Solids.

Bio-solids (biological sludge) from wastewater treatment plants are a significant source of the emission of microplastics (MPs) into the environment. Weakening the structure of MPs before they enter the environment may accelerate their degradation and reduce the environmental exposure time. Therefore, we studied the effect of UV-A and UV-C, applied at 70 °C, on three types of MPs, polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET), that are commonly found in sewage sludge, using three shapes (fibers, lines, granules). The MPs were exposed to UV radiation in bio-solid suspensions, and to air and water as control. The structural changes in and degradation of the MPs were investigated using Attenuated Total Reflectance-Fourier Transform Infrared Spectrometry (ATR-FTIR) and surface morphology was performed with SEM analysis. UV exposure led to the emergence of carbonyl and hydroxyl groups in all of the PP samples. In PE and PET, these groups were formed only in the bio-solid suspensions. The presence of carbonyl and hydroxyl groups increased with an increasing exposure time. Overall, UV radiation had the greatest impact on the MPs in the bio-solids suspension. Due to the surface-to-volume ratio of the tested samples, which influences the degradation rate, the fibers were more degraded than the other two plastic shapes. UV-A was slightly more effective at degrading the MPs than UV-C. These findings show that ultraviolet radiation in combination with an elevated temperature affects the structure of polymers in wastewater bio-solids, which can accelerate their degradation.

Ultraviolet disinfection of water in recirculating aquaculture system: a case study at sturgeon caviar fish farm

In this report, we present a practical example of ultraviolet (UV) water disinfection in an aquaculture facility for sturgeon caviar production. Among the methods of water disinfection in recirculating aquaculture systems, the technical approaches using ozonation or ultraviolet radiation in combination with other methods are the most effective. However, improper use of ozonation can result in excessive ozone concentrations that can cause serious harm to fish and be harmful to the environment and personnel. Therefore, we describe an example of a reagent-free ultraviolet water disinfection system. Preliminary results show that filtration followed by ultraviolet irradiation inactivates microorganisms in fish tank water. Total microbial count, total coliform bacteria, and E. coli (CFU/m3) did not exceed the permissible values. The described UV system provides an irradiance of 180 W/m2. For a pool with a water volume of 300 m3, bacteriological purity of the water was achieved with 480 W of UV-light.

Effect of combined phototherapy and regulatory polypeptide selank on cytokine blood profile of patients with atopic dermatitis

Aim. To evaluate the effectiveness of complex therapy using the regulatory polypeptide selank and combined narrow-band medium-wave and wide-band long-wave ultraviolet (UV) radiation in the correction of the cytokine blood profile and immunoglobulin E (IgE) level in patients with atopic dermatitis (AD).Material and methods. In a group of 124 patients with medium-heavy AD (61 men, 63 women; average age 23.7 ± 6.06 years), a comparative analysis of the effect of therapy on the interleukins (IL) -1β,-4,-10,-13, immunoglobulin E (IgE) blood levels was performed. We compared the results of basic drug treatment (BT), additional prescription of selank (S), combined UV phototherapy (CFT) in the range of 311 nm and 320–400 nm, as well as complex therapy (S + CFT + BT).Results. The immune status of AD patients is characterized by high blood levels of IL‑1β,-4,-10,-13 and IgE in comparison with healthy individuals. Standard drug therapy had the least effect on the cytokine profile and level IgE blood of patients. The use of selank increases the anti-inflammatory effect of BT. The regulatory effect on cytokine activity and level IgE is even more significantly enhanced with the use of CFT. The most pronounced immunocorrective effect was demonstrated by complex therapy with the use of combined UV radiation techniques and selank.Conclusions. The use of a combined narrow-band medium-wave (311 nm) and wide-band long-wave (320–400 nm) UV radiation and regulatory polypeptide drug (selank) causes the most pronounced positive effect on the cytokine blood profile and IgE level in patients with AD, which indicates a greater anti-inflammatory activity of this treatment method (p < 0.001) compared to the monotherapy groups and basic therapy (p < 0.001).

Results of efferent therapy in monochorionic diamniotic twins with dissociation of fetal development (three clinical observations)

The article presents three clinical observations of successful conservative treatment of pregnant women with monochorionic, diamniotic twins (MDT), coming naturally. In all cases, there were manifestations of twin-to-twin transfusion syndrome (TTTS) with progressive blood flow disorders in the utero-placental space with a pronounced delay in the development of one of the fetuses. In the early stages of pregnancy was supposed to terminate the pregnancy, but the women refused. Pregnant women were admitted to the perinatal center at 23, 23 and 24-25 weeks, respectively. During the examination, the diagnosis was confirmed, at the same time in all cases, the patients found manifestations of endotoxicosis and inflammatory response. Pregnant conducted methods of detoxicational (efferent) therapy in the form of photomodification of blood with sessions of laser and ultraviolet radiation in combination: in the first case — plasmaexchange with 5% albumin solution No 6 and the cascading plasmafiltration No 5; in the second observation - with medium volume plasmapheresis No 7, hemosorption No 1; in the 3rd observation – with plasmapheresis No 7, hemosorption No 3. Complications at efferent therapy was not, indices of homeostasis of pregnant women in the dynamics normalized. Blood flow disorders in the placenta persisted, but there was a steady increase in body weight of the fetus. In general, women’s pregnancies were prolonged for 11, 13 and 9 weeks, respectively (in the first two cases, women were even temporarily discharged home). Childbirths in all cases were performed by operational pathway, there were no complications in childbirth and after childbirth in mothers. All six children were born alive with mild and moderate prematurity and did not need long-term intensive care. All were on breast-feeding, in dynamics surveillance caught up with contemporaries in development.

A novel microwave combined ultraviolet radiator based on slotted coaxial line for epoxy resin curing

Curing resin matrix composite quickly constitutes one of the key technologies for industrial lightweight production, especially in automobile manufacturing and aircraft maintenance. In this study, a novel gap coaxial line microwave combined ultraviolet radiator is proposed for epoxy resin curing. With the same power of 100 W, epoxy resin is cured both by the proposed radiator working at a microwave frequency of 2.45 GHz and single ultraviolet. Respectively, the ultraviolet radiation and microwave combined ultraviolet radiation are measured. The microwave radiation and plasma absorption of this radiator is close to 3:4 by simulation and experiment. In addition, experimental results indicate that the processing time using this radiator is 3.6 times shorter than using single ultraviolet. The toughness and adhesiveness of the epoxy resin after curing are compared by scanning electron microscope and X-ray diffusion, and the fracture surface of the cured epoxy resin demonstrates that microwave combined ultraviolet curing is more effective.

The Janus face of iron on anoxic worlds: iron oxides are both protective and destructive to life on the early Earth and present-day Mars.

The surface of the early Earth was probably subjected to a higher flux of ultraviolet (UV) radiation than today. UV radiation is known to severely damage DNA and other key molecules of life. Using a liquid culture and a rock analogue system, we investigated the interplay of protective and deleterious effects of iron oxides under UV radiation on the viability of the model organism, Bacillus subtilis. In the presence of hydrogen peroxide, there exists a fine balance between iron oxide's protective effects against this radiation and its deleterious effects caused by Photo-Fenton reactions. The maximum damage was caused by a concentration of hematite of ∼1 mg/mL. Concentrations above this confer increasing protection by physical blockage of the UV radiation, concentrations below this cause less effective UV radiation blockage, but also a correspondingly less effective Photo-Fenton reaction, providing an overall advantage. These results show that on anoxic worlds, surface habitability under a high UV flux leaves life precariously poised between the beneficial and deleterious effects of iron oxides. These results have relevance to the Archean Earth, but also the habitability of the Martian surface, where high levels of UV radiation in combination with iron oxides and hydrogen peroxide can be found.

Saharan dust inputs and high UVR levels jointly alter the metabolic balance of marine oligotrophic ecosystems.

The metabolic balance of the most extensive bioma on the Earth is a controversial topic of the global-change research. High ultraviolet radiation (UVR) levels by the shoaling of upper mixed layers and increasing atmospheric dust deposition from arid regions may unpredictably alter the metabolic state of marine oligotrophic ecosystems. We performed an observational study across the south-western (SW) Mediterranean Sea to assess the planktonic metabolic balance and a microcosm experiment in two contrasting areas, heterotrophic nearshore and autotrophic open sea, to test whether a combined UVR × dust impact could alter their metabolic balance at mid-term scales. We show that the metabolic state of oligotrophic areas geographically varies and that the joint impact of UVR and dust inputs prompted a strong change towards autotrophic metabolism. We propose that this metabolic response could be accentuated with the global change as remote-sensing evidence shows increasing intensities, frequencies and number of dust events together with variations in the surface UVR fluxes on SW Mediterranean Sea. Overall, these findings suggest that the enhancement of the net carbon budget under a combined UVR and dust inputs impact could contribute to boost the biological pump, reinforcing the role of the oligotrophic marine ecosystems as CO2 sinks.

Disinfection characteristics of the combined ultraviolet radiation and ozone process using Escherichia coli as a probe

In the present study, the characteristics of the combined ultraviolet (UV) and ozone disinfection process were investigated from kinetic and mechanistic viewpoints employing Escherichia coli (E. coli) as an indicator microorganism. Compared to individual unit processes, the combined UV/O3 tests produced excess hydroxyl radicals (HO•) and yielded synergistic inactivation of E. coli in the initial phase of reaction. The presence of O3 during UV exposure caused the destruction of cell structure, and then repressed bacteria regrowth after treatment. Moreover, the formation of malondialdehyde (MDA) showed that the improved generation of intermediate HO• via ozone photolysis accelerated the decomposition of bacterial cell surfaces, which was further confirmed by the leakage of intracellular potassium ions (K+). The results suggested that the synergistic bactericidal effect of combined UV/O3 owed mainly to the enhanced destruction of bacterial cell structure.

Fitness costs and benefits of ultraviolet radiation exposure in marine pelagic copepods

Summary Life‐history theory predicts that organisms should allocate energy throughout their life such that they maximize their fitness. Copepod zooplankton are known to accumulate sunscreens (so‐called mycosporine‐like amino acids, MAAs) and antioxidant carotenoids to mitigate negative effects of ultraviolet radiation (UVR), but it is not well known how this affects their fitness. We followed cohorts of the marine copepod Acartia tonsa and assessed how fitness was affected by UVR exposure and a diet rich in UVR‐protective sunscreens. Several fitness components including somatic growth, egg quality and nauplii production (larvae) were negatively affected by UVR, whereas other components such as size at maturity, survival and length of life were not. Nauplii production through low egg quality was the most influential life‐history parameter that changed in response to UVR. There was interaction between fitness costs and food source. If copepods were fed a diet rich in UVR‐screening MAAs, they were able to maintain and even increase their fitness even though they were exposed to otherwise detrimental radiation. Levels of UVR‐protective carotenoids were low in the studied species and a meta‐analysis revealed that marine copepods in general have much lower – by an order of magnitude – levels of carotenoids than freshwater species, while levels of MAAs are similar between the two habitats. We conclude that allocation to different fitness components to some extent is plastic although egg quality is by far the most influential factor, and this is an example of how environmental variability affects overall fitness. Fitness costs associated with UVR exposure in the absence of UVR‐screening MAAs were present. Other costs such as costs for accumulating MAAs were not detected, and if present, they were outweighed by a stimulated fitness in combined UVR and MAA treatments challenging the common model that inducible defences (such as accumulation of MAAs) should come with a cost. Low levels of carotenoids in marine systems suggest high predation pressures on pigmented specimens. Accumulation of nonpigmented MAAs could hence be a key adaptation for surface‐dwelling marine zooplankton to maintain or even increase their fitness when exposed to detrimental radiation.

Pilot-scale UV/H2O2 advanced oxidation process for surface water treatment and downstream biological treatment: effects on natural organic matter characteristics and DBP formation potential

The effects of the advanced oxidation process (AOP) of ultraviolet radiation in combination with hydrogen peroxide (UV/H2O2) on the structure and biodegradability of dissolved natural organic matter (NOM) and on the formation of disinfection by-products (DBPs) through the post-UV/H2O2 chlorination were investigated using UV reactors equipped with either low-pressure amalgam lamps or medium-pressure mercury vapour lamps. With electrical energy doses and H2O2 concentrations typically applied in full-scale UV systems for water remediation, the UV/H2O2 AOP partially oxidized NOM, reducing its degree of aromaticity and leading to an increase in the level of biodegradable species. Also, when combined with a downstream biological activated carbon (BAC) filter, UV/H2O2 AOP reduced the formation of DBPs by up to 60% for trihalomethanes and 75% for haloacetic acids. Biological activated carbon was also shown to effectively remove biodegradable by-products and residual H2O2.

Effects of ultraviolet radiation on morphology and thermo-mechanical properties of shape memory polymer based syntactic foam

Recently, shape memory polymer (SMP) based close-celled syntactic foam has been developed as a lightweight self-healing composite or sealant in expansion joints. In this study, SMP based syntactic foam was prepared and programmed by 2-D stress condition (compression in one direction and tension in a transverse direction). To investigate the durability of the smart foam under environmental attacks, accelerated aging of up to 90 days exposure to ultraviolet (UV) radiation was conducted. Combined UV radiation and water immersion (rain water and saturated salt water) were also investigated. The effect of various environmental attacks on the morphological, mechanical, and functional properties of the foam was evaluated. It is found that, although the accelerated aging by UV or/and water leads to a decrease in strength, ductility and shape recovery functionality, the decrease is insignificant. The 2-D programmed foam after environmental attacks is still able to serve as an effective shape memory material.

Estimating Surface Damage of Composite Panels with Inverse Analysis

When composite structures are exposed to harsh environmental conditions or impacted by foreign objects, their surfaces may degrade or damage. Damage evaluations of composite panels often demand expensive tools and time-consuming processes. The aim of this work is to introduce a versatile inverse analysis based method that requires less measurement efforts than those of conventional techniques. In this procedure, first, strains are measured on a surface opposite to damaged surface. Then, general functions relating damage conditions to strain fields are established. These functions reduce computational efforts required during the damage identification. With the measured strains and functions, an error objective function is minimized via iterations to estimate the damage extent. To verify the effectiveness of this proposed procedure, a detailed simulation study is performed with cross-ply composite laminates possessing various damage. The results show excellent matches between the estimated damage fields and the specified conditions imposed on the models. Following this promising outcome, the proof of concept study is extended to several real cross-ply composite panels that are damaged by either sand-blasting or environmental exposure. In the latter case, the composites were exposed to combined ultraviolet radiation and moisture absorption. On composite specimens, spatial variations of strain fields are measured with strip strain-gauges. Then they are used to identify surface damage distributions with either the quadratic formulation or the B-spline method. The latter approach is suitable when the functional change of strains due to damage is not smooth. The results estimated the variation of damage extent in each specimen. This feasibility study clearly supports the possibility of using strain sensor-network or optical method to quantify surface damage.

Ethanol and aloe emodin alter the p53 mutational spectrum in ultraviolet radiation-induced murine skin tumors.

Mutations in the p53 tumor-suppressor gene contribute to the development of skin cancer, and the spectrum of mutations in this gene correlates with specific physical and chemical carcinogens in the environment. Cosmetics may contain alcohols and/or aloe emodin (AE). Although these compounds are not carcinogenic when applied to the skin, they may increase the carcinogenicity of ultraviolet (UV) radiation. We investigated whether ethanol (EtOH) and AE alone or combined with UV radiation cause mutations in the p53 gene. In the absence of UV radiation, C3H/HeN mice chronically treated for up to 33 wk with AE in 25% EtOH-in-water vehicle or vehicle alone failed to develop tumors and had no mutations in exons 4-8 of the p53 gene. UV radiation alone induced skin tumors, which had mutations predominantly in p53 exons 5 and 8. In contrast, mutations arising in UV + EtOH-or UV + AE-treated groups were more broadly distributed throughout the p53 gene. Mutations were found in exons 4, 6, and 7, as well as in exons 5 and 8. This altered distribution of mutations across the p53 DNA sequence more closely resembles the pattern observed in TP53 from human skin tumors at sun-exposed sites than that in the p53 gene of mice treated with UV alone. Thus, treatment with UV radiation in combination with two chemicals not thought to be carcinogenic, alcohol, and AE results in a broader distribution of mutations in a critical tumor-suppressor gene.

Spatial distribution of environmental stress indicators in Concord grape vineyards

Concord grapes ( Vitis labrusca L.) in Washington, USA suffer from ‘blackleaf’ disorder, which darkens the foliage to purplish-brown and black in sun-exposed leaves of the outer canopy. Recently, blackleaf has been related to ultraviolet radiation in combination with water-deficit stress, although blackleaf development varies within and among vineyards. This study used digital image analysis, mapping, and semivariogram models to determine if blackleaf or its reciprocal greenness, demonstrates spatial variability within Washington vineyards, and if so, to characterize development of that spatial structure throughout the growing season. In 1998, digital color images were taken in one commercial and one research vineyard. Images taken directly above the vines were captured at key phenological stages (fruit set, veraison, and harvest). Individual images were analyzed for blackleaf symptoms, demonstrated by a low proportion of greenness, and each measurement was associated with a vine location for use in geostatistical procedures and mapping. Declines in greenness occurred throughout the growing season in both vineyards. Spatial auto-correlation was strongest early in the season with 39–51% of the variation explained by spatial location. Results suggest greenness is spatially dependent early in the season, but as the season progresses and the canopy expands, greenness loses its association with spatial location until blackleaf expression becomes more pervasive late in the season. This research presents insight into the seasonal and spatial development of blackleaf in an agroecosystem. It also presents a method for detecting and mapping early to mid-season indications of environmental stress to facilitate site-specific management practices.

Comments on “Optical Surface Degradation from Combined Ultraviolet Radiation and Outgassed Materials” by J. F. Scannapieco and R. N. Griffin

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Reply to W. R. Hunter’s “Comments on Optical Surface Degradation from Combined Ultraviolet Radiation and Outgassed Materials”

Reply to W. R. Hunter’s “Comments on Optical Surface Degradation from Combined Ultraviolet Radiation and Outgassed Materials”

Optical Surface Degradation from Combined Ultraviolet Radiation and Outgassed Materials

Among problems, which have been encountered in testing and flight of spacecraft, have been those related to the outgassing of materials in vacuum. Two of the major problems caused by outgassing are electrical corona discharge, and condensation onto critical surfaces. The surfaces of a spacecraft most susceptible to damage by condensation of a foreign material are those used for thermal control and those used in optical systems. This paper describes the techniques used to determine the effects of outgassed materials condensed on MgF2 over-coated aluminum mirrors while the mirrors were irradiated with ultraviolet light in vacuum. Mirror temperatures as low as −60 °C were used to determine the point at which condensation was incipient. The measurements performed on these mirrors included reflectance at Lyman α (1216 Å) and infrared analysis of the deposit. The initial results obtained with this system demonstrate that Lyman α reflectance is essentially unaffected by heavy condensates of some materials but almost completely destroyed by very thin deposits of other materials.