On the Development of Spatial/Temporal Solar UV Irradiation Maps: A Case Study in Pernambuco State (Northeast of Brazil)

This work summarizes recently published information on the solar UV broadband irradiation of Pernambuco, Northeast of Brazil. We describe the spatial and temporal distribution of solar UV radiation and its relationship with climatic and geographical conditions. Statistical experimental correlation between solar total irradiation and UV broadband obtained for 03 locations was generalized by the use of Koppen-Geiger Climatic criterium, which was used for mapping the spatial/temporal distribution of broadband UV. The climatological solar radiations used in the correlations were obtained by modeling through satellite and previously verified with terrestrial data. We present one map with the location of the recording stations where the statistical correlations were measured, one annual and 12 monthly contour maps describing monthly daily solar UV radiation levels throughout the territory of Pernambuco. The solar UV irradiation (“broadband”) annual-average daily value in the State of Pernambuco varied from 226 to 268 Wh/m2. Seasonal variation of solar UV irradiation in the State of Pernambuco follows, in general and as expected, the climate, relief and seasons of the year. The highest value of monthly solar UV irradiation was observed in the central south region of the state, more precisely in Belém do São Francisco, Floresta, Ibimirim and Buíque in the month of December (summer), with 311.8 Wh/m2. The lower value was found in the south Agreste region, in Garanhuns and Caruaru, in the month of June (winter), with 162.2 Wh/m2.

Protective Effect of Gelatin and Gelatin Hydrolysate from Salmon Skin on UV Irradiation-Induced Photoaging of Mice Skin

The objective of this study was to investigate the effect of gelatin(SG) isolated from salmon skin and its hydrolysate(SGH) on photoaging skin, and the mechanism responsible for anti-photoaging. The average molecular weights of SG and SGH were 65 k Da and 873 Da, respectively. The amino acid compositions of SG and SGH were similar. Both of them were abundant in hydrophobic amino acids. Twenty-five peptides were identified from SGH. SG and SGH could improve UV irradiation-induced pathological changes of macroscopical tissue texture and skin morphology. Hydroxyproline content is an indicator of matrix collagen content, SG and SGH could inhibit the decrease of hydroxyproline content in photoaging skin in a dose dependent manner. In addition, SG and SGH could alleviate UV irradiation-induced oxidative damages to skin by increasing the activities of total superoxide dismutase(T-SOD), glutathione peroxidase(GSH-Px) and catalase(CAT), increasing the content of glutathione(GSH) and decreasing the content of malonaldehyde(MDA). Moreover, SG and SGH could enhance immune regulation system by increasing the thymus index. Thus, the anti-photoaging mechanisms of SG and SGH were by inhibiting the depletion of antioxidant defense components, involving in the synthesis of collagen and enhancing the function of immune system. Besides, SGH showed a better result in protecting skin from photoaging than SG.

Electrochemical biosensing for dsDNA damage induced by PbSe quantum dots under UV irradiation

An electrochemical sensor for the detection of the natural double-stranded DNA(dsDNA) damage induced by PbSe quantum dots(QDs) under UV irradiation was developed.The biosensing membranes were prepared by successively assembling 3- mercaptopropionic acid,polycationic poly(diallyldimethyl ammonium) and dsDNA on the surface of the gold electrode.Damage of dsDNA was fulfilled by immersing the sensing membrane electrode in PbSe QDs suspension and illuminating it with an UV lamp. Cyclic voltammetry was utilized to detect dsDNA damage with Co(phen)_3^(3+) as the electroactive probe.The UV irradiation,Pb^(2+) ions liberated from the PbSe QDs under the UV irradiation and the reactive oxygen species(ROS) generated in the presence of the PbSe QDs also under the UV irradiation were the three factors of inducing the dsDNA damage.The synergistic effect of the three factors might dramatically enhance the damage of dsDNA.This electrochemical sensor provided a simple method for detecting DNA damage,and may be used for investigating the DNA damage induced by other QDs.

Decomposition of aqueous chlorinated contaminants by UV irradiation with H2O2

In the present study, the decomposition rates of carbon tetrachloride （CC14） and 2,4-dichlorophenol （2,4- DCP） in water by the ultraviolet （UV） light irradiation alone and H2O2AYV were experimentally investigated. The detailed experimental studies have been conducted for examining treatment capacities of the two different ultraviolet light sources （low and medium pressure Hg arc） in H2O2/UV processes. The low or medium UV lamp alone resulted in a 60%-90% decomposition of 2,4-DCP while a slight addition of H2O2 resulted in a drastic enhancement of the 2,4-DCP decomposition rate. The decomposition rate of 2,4-DCP with the medium pressure UV lamp alone was about 3-6 times greater than the low pressure UV lamp alone. In the direct photolysis of aqueous CC14, the medium pressure UV lamp had advantage over the low pressure UV lamp because the molar extinction coefficient of CC14 at shorter wavelength （210-220 nm） is about 20 to 50 times higher than that at 254 nm. However, adding H202 to the medium pressure UV lamp system rendered a negative oxidation rate because H202 acted as a UV absorber being competitive with CC14 due to negligible reaction between CC14 and OH radicals. The results fi：om the present study indicated significant influence of the photochemical properties of the target contaminants on the photochemical treatment characteristics for designing cost-effective UV-based degradation of toxic contaminants.

Completely Green Synthesis of Ag Nanoparticles Stabilized by Soy Protein Isolate under UV Irradiation

A completely green pathway for the preparation of Ag nanoparticles was proposed, by using soy protein isolate （SPI） as stabilizer under UV irradiation and H2O as the environmentally benign solvent throughout the preparation. Transmission electronic microscopy （TEM） and zeta potential characterization results indicated that the Ag nanoparticles were stable and well dispersed with an average diameter about 13 nm, and X-ray diffraction （XRD） analysis of SPI/Ag composite nanoparticles confirmed the formation of metallic silver. UV-Vis spectrum showed that the Ag nanoparticles dispersion solution had the maximum absorbance at about 430 nm due to surface plasmon resonance of the Ag nanoparticles. Infrared spectroscopy confirmed that the polypeptide backbone of SPI was not cleaved during the conjugation process and that some active amino groups were oxidized. The SPI/Ag composite nanoparticles have excellent antibacterial activity against two representative bacteria, staphylococcus aureus （Gram positive） and escherichia coli （Gram negative） in the presence of SPI.

Effect of UV Irradiation on PAN Precursor Fibers and Stabilization Process

A low-cost rout for modification the polyacrylontrile（PAN） precursor fibers was developed.The approach involved pretreatment PAN precursor fibers with UV irradiation for various periods of time before the fibers were stabilized.The effect of UV irradiation on the chemical structure,orientation factor,density,crystallite size and morphology of the fibers in the process of stabilization was characterized by use of fourier transform infrared spectroscopy（FTIR）,float-sink procedure,X-ray diffraction（XRD）,scanning electron microscope（SEM）,respectively.The results showed that UV irradiation could increase the density of the fibers in stabilization process.FTIR analysis indicated that the cyclization of nitrile groups was initiated at room temperature by UV irradiation.The transformation of C≡N groups to C=N ones was accelerated in the process of stabilization.The orientation factor of irradiated fibers was also increased.The crystallite size was decreased at first and increased later,and the better irradiation time of UV was 3 min according to the XRD test.SEM analysis indicated that irradiation could decrease the internal and surface defects of the stabilized fibers treated at 300 ℃.

THE EFFECTS OF MAGNETIC FIELD ON GRAFT COPOLYMERIZATION OF METHYL METHACRYLATE ONTO POLYVINYL ALCOHOL IN THE PRESENCE OF BENZOPHENONE DURING UV IRRADIATION

The effects of magnetic field on the graft ratio and stereoregularity of grafts of PVA-g-MMA in the presence ofbenzophenone during UV irradiation are discussed. By means of IR, it was found that the graft ratio was increased with the increment of magnetic field strength. Furthermore, application of relative weak magnetic field of 0.4 Tesla had been shown to substantially enhance the stereo-regularity of graft copolymer. The maximum stereo-regularity appeared when the graft ratio approached to 85% with the magnetic field of 1.2 Tesla (T). The resistance to moisture and heat resistance of the grafted copolymer in the presence of magnetic field were also improved.

AN INVESTIGATION ON THE INTERACTION MECHANISM OF β-CAROTENE WITH HALOGEN ATOM PRODUCED IN HALOBENZENE BY UV IRRADIATION

ESR measurements using spin trapping technique were carried out for β-carotene-halobenzene system under UV light irradiation.The ESR spectra observed in the presence and in the absence of β-carotene are markedly different.The possible scheme of β-carotene interacting with halogen atom was proposed.

Photochemical Reactions of Microcystin-LR Following Irradiation with UV Light

Photochemical reactions of microcystin-LR, a toxic compound produced by some blue green algae, were investigated. Ultraviolet absorption of microcystin-LR was assessed. Time-dependent density functional theory (TDDFT) calculations indicated that absorption peak at 238 nm was mainly due to excitation of electrons from the linear chain structure Adda of microcystin-LR. Irradiation of microcystin-LR with UV light resulted in the reduction of the 238 nm absorption peak and the appearance of a new peak at 300 nm. Density functional theory (DFT) and TDDFT calculations with a model molecule suggested that this 300 nm peak was due to tricyclo-Adda microcystin-LR, an intermediate in photochemical reactions of microcystin-LR. Analysis of the rate of this photochemical reaction showed that it was a first order reaction.

Anti-fouling ultrafiltration membrane prepared from polysulfone-graft-methyl acrylate copolymers by UV-induced grafting method

Membrane fouling is one of the most important challenges faced in membrane ultrafiltration operations. The copolymers of polysulfone-graft-methyl acrylate were synthesized by homogeneous photo-initiated graft copolymerization. The variables affecting the degree of grafting, such as the time of UV （Ultraviolet-visible） irradiation and the concentrations of the methyl acrylate and photoinitiator, were investigated. The graft copolymer membranes were prepared by the phase inversion method. The chemical and morphological changes were characterized by attenuated total reflection-Fourier transform infrared spectroscopy （ATR/FT-IR）, scanning electron microscopy, and water contact angles measurements. Results revealed that methyl acrylate groups were present on the membranes and the graft degree of methyl acrylate had remarkable effect on the performance of membranes. Pure water contact angle on the membrane surface decreases with the increase of methyl acrylate graft degree, which indicated that the hydrophilicity of graft copolymer membranes was improved. The permeation fluxes of pure water and bovine serum albumin solution were measured to evaluate the antifouling property of graft copolymer membranes, the results of which have shown an enhancement of antifouling property for graft copolymer membranes.

Structural, Optical and Photocatalytic Properties of Cu2+ Doped ZnO Nanorods with Using HMTA Solvent Prepared by Hydrothermal Method

In this experiment, Cu2+ doped ZnO (Cu-ZnO) nanorods materials have been fabricated by hydrothermal method. Cu2+ ions were doped into ZnO with ratios of 2, 5 and 7 mol.% (compared to the mole’s number of Zn2+). The hexamethylenetetramine (HMTA) solvent used for the fabrication of Cu-ZnO nanorods with the mole ratio of Zn2+:HMTA = 1:4. The characteristics of the materials were analyzed by techniques, such as XRD, Raman shift, SEM and UV-vis diffuse reflectance spectra (DRS). The photocatalytic properties of the materials were investigated by the decomposition of the methylene blue (MB) dye solution under ultraviolet light. The results show that the size of Cu-ZnO nanorods was reduced when the Cu2+ doping ratio increased from 2 mol.% to 7 mol.%. The decomposition efficiency of the MB dye solution reached 92% - 97%, corresponding to the Cu2+ doping ratio changed from 2 - 7 mol.% (after 40 minutes of ultraviolet irradiation). The highest efficiency for the decomposition of the MB solution was obtained at a Cu2+ doping ratio of 2 mol.%.

Modeling of secondary treated wastewater disinfection by UV irradiation: Effects of suspended solids content

This work aimed to study UV-resistant strains of Pseudomonas aeruginosa, to propose a formulation of the kinetics of secondary treated wastewater disinfection and to underline the influence of suspended solids on the inactivation kinetics of these strains. Some investigations were carried out for the validation of some simulation models, from the simplest, the kinetics model of Chick-Watson reduced to first order, to rather complex models such as multi-kinetic and Collins-Selleck models. Results revealed that the involved processes of UV irradiation were too complex to be approached by a simplified formulation, even in the case of specific strains of microorganisms and the use of nearly constant UV radiation intensity. In fact, the application of Chick-Watson model in its original form is not representative of the kinetics of UV disinfection. Modification, taking into account the speed change during the disinfection process, has not significantly improved results. On the other hand, the application of Collins-Selleck model demonstrates that it was necessary to exceed a least dose of critical radiation to start the process of inactivation. To better explain the process of inactivation, we have assumed that the action of disinfectant on the survival of lonely microorganisms is faster than its action on suspended solids protected or agglomerated to each others. We can assume in this case the existence of two inactivation kinetics during the processes （parallel and independent） of the first-order. For this reason, the application of a new kinetic model by introducing a third factor reflecting the influence of suspended solids in water on disinfection kinetics appeared to be determinant for modeling UV inactivation of P. aeruginosa in secondary treated wastewater.

Bromate ion formation in dark chlorination and ultraviolet/chlorination processes for bromide-containing water

Bormate （BrO3^-） is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions, particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet （UV）/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards （10 μg/L）. UV irradiation enhanced the decay of free chlorine, and, simultaneously, 6.6%-32% of Br^- was oxidized to BrO3^-. And the formation of bromate exhibited three stages： rapid stage, slow stage and plateau. Under the experimental conditions （pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L）, low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.

Synthesis of Bimodal Mesoporous TiO_(2)-PTA/BMMS and Its Enhanced Performance in the Photocatalytic Oxidative Desulfurization

With the bimodal mesoporous silica(BMMS)acting as the support and the composite of TiO2 with phosphotungstic acid(PTA)functioning as the active constituent,TiO_(2)-PTA/BMMS was synthesized by the two-step impregnation route.This catalyst was applied in the photocatalytic oxidative desulfurization(PODS)process,with dibenzothiophene serving as the model sulfur compound.PODS proceeds in one pot,in which H_(2)O_(2) acts as the oxidant and methanol plays the role of the solvent.TiO_(2)-PTA/BMMS was characterized by XRD,N_(2) adsorption and desorption,XRF,FTIR,UV-vis,SEM,EDS and TEM techniques.It showed that the introduction of PTA contributes higher order,higher surface area and pore volume to the bimodal mesoporous support.With TiO_(2)-PTA/BMMS used as the catalyst under the UV irradiation,the desulfurization rate can reach 99.6%.This result is obviously higher than that achieved by TiO_(2)/BMMS.The catalyst also has no significant drop in catalytic activity after eight runs of reusing.In such catalytic system,the synergistic effects of this photocatalytic oxidation and the extraction with the methanol serving as the solvent played an indispensable role.

EFFECTS OF ORGANIC COLORANTS ON PHOTO-INITIATED CROSSLINKING AND PHOTO-OXIDATION DEGRADATION OF POLYETHYLENE AND RELATED MECHANISM

The effects of three organic colorants on photo-initiated crosslinking and photo-oxidation degradation of polyethylene (PE) samples irradiated by microwave excited (MWE) UV lamp in the melt and the related mechanism have been studied by gel content and thermal extension rate determinations,X-ray photoelectron spectroscopy (XPS),mechanical property tests,UV spectroscopy,and light microscope.The data from the gel content and thermal extension rate determinations of photo-crosslinked polyethylene (XLPE) sample...

Photo-Grafting Copolymerization of PP Nonwoven Fabric and Its Application for Acidic Dye Adsorption and Filtration

The monomer methacrylamido propyl trimethy ammonium chloride( MAPTAC) was copolymerized onto the fiber surface of polypropylene( PP) nonwoven fabric under ultroviole radiation. The weak acid red GN dye adsorption and adsorptive filtration performance of the resulted PP fabrics were investigated.The results showed that the grafting copolymerization preferred to happen in the inner layer of the fabrics. The water flux of the grafted fabrics decreases with the increase of grafting yield. The collapse of the grafted polymer chains causes the flux increase in acidic condition,or vice versa at alkaline version. The coiling of the polyelectrolyte chains upon the dye adsorption seems to violate the routine assumption of the rigid substrate, and this gets the adsorption energy constant negative. The static adsorption process follows the Lagergren's pseudo-second order kinetic equation. The removals of circa( ca.) 100% of the total permeation volume3 500 mL simulated dye wastewater was reached during permeation.The dye adsorbed fabrics were regenerated by the mixed media of the cationic surfactant / ethanol /water. The grafted fabric assumes stable fabric integrity and stability during permeation,and presents excellent dye adsorption capacity,easy desorption, and repeatable utilization.

Photolysis of polycyclic aromatic hydrocarbons on soil surfaces under UV irradiation

Photolysis of some polycyclic aromatic hydrocarbons （PAHs） on soil surfaces may play an important role in the fate of PAHs in the environment.Photolysis of PAHs on soil surfaces under UV irradiation was investigated.The effects of oxygen,irradiation intensity and soil moisture on the degradation of the three PAHs were observed.The results showed that oxygen,soil moisture and irradiation intensity enhanced the photolysis of the three PAHs on soil surfaces.The degradation of the three PAHs on soil surfaces is related to their absorption spectra and the oxidation-half-wave potential.The photolysis of PAHs on soil surfaces in the presence of oxygen followed pseudo first-order kinetics.The photolysis half-lives ranged from 37.87 days for benzo[a]pyrene to 58.73 days for phenanthrene.The results indicate that photolysis is a successful way to remediate PAHs-contaminated soils.

Administration with Bushenkangshuai Tang alleviates UV irradiation- and oxidative stress-induced lifespan defects in nematode Caenorhabditis elegans

During normal metabolism,oxidative bypro-ducts will inevitably generate and damage molecules thereby impairing their biological functions,including the aging process.Bushenkangshuai Tang(补肾抗衰方,BT)is a traditional Chinese medicine widely used for clini-cally treating premature ovarian failure.In the present study,BT administration at high concentrations signifi-cantly increased lifespan,slowed aging-related decline,and delayed accumulation of aging-related cellular damage in wild-type Caenorhabditis elegans.BT admin-istration could further largely alleviate the aging defects induced by UV and oxidative stresses,and BT administra-tion at different concentrations could largely rescue the aging defects in mev-1 mutant animals.The protective effects of BT administration on aging process were at least partially dependent on the Ins/IGF-like signaling pathway.Moreover,BT administration at different concentrations obviously altered the expression patterns of antioxidant genes and suppressed the severe stress responses induced by UV and oxidative stresses,suggesting that BT-induced tolerance to UV or oxidative stress might result from reactive oxygen species scavenging.BT administration during development was not necessarily a requirement for UV and oxidative stress resistance,and the concentrations of administrated BT examined were not toxic for nematodes.Therefore,BT administration could effectively retrieve the aging defects induced by UV irradiation and oxidative stress in Caenorhabditis elegans.

POLYELEOSTEARIC ACID VESICLES

α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solution of eleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.

Interaction of Co（ll） with Bovine Serum Albumin under UV C Irradiation

The interaction of Co（Ⅱ） with BSA under UV C （253.7 nm） irradiation under physiological conditions has been studied by UV-vis spectrum, ultraviolet second-derivative spectroscopy and fluorescence spectrum. The quenching rate constant kq and the association constant Ka were calculated according to Stern-Volmer equation based on the quenching of the fluorescence of BSA by Co（Ⅱ）.