UVA Light Research Articles

Solvent-thermal approach of MIL-100(Fe)/Cygnea/Fe3O4/TiO2 nanocomposite for the treatment of lead from oil refinery wastewater (ORW) under UVA light

The main purpose of this research endeavor is to reduce lead concentrations in the wastewater of an oil refinery through the utilization of a material composed of oyster shell waste (MIL-100(Fe)/Cygnea/Fe3O4/TiO2. Initially, iron oxide nanoparticles (Fe3O4) were synthesized via solvent-thermal synthesis. It was subsequently coated layer by layer with the organic–metallic framework MIL-100 (Fe) using the core–shell method. Additionally, the solvent-thermal method was utilized to integrate TiO2 nanoparticles into the magnetic organic–metallic framework’s structure. Varieties of analytical analysis were utilized to investigate the physical and chemical properties of the synthetic final photocatalyst. Nitrogen adsorption and desorption technique (BET), scanning electron microscopy (SEM), scanning electron diffraction pattern (XRD), and transmission electron microscopy (TEM). Following the characterization of the final photocatalyst, the physical and chemical properties of the nanoparticles synthesized in each step, several primary factors that significantly affect the removal efficiency in the advanced oxidation system (AOPs) were examined. These variables consist of pH, photocatalyst dosage, lead concentration, and reaction temperature. The synthetic photocatalyst showed optimal performance in the removal of lead from petroleum wastewater under the following conditions: 35 °C temperature, pH of 3, 0.04 g/l photocatalyst dosage, and 100 mg/l wastewater concentration. Additionally, the photocatalyst maintained a significant level of reusability after undergoing five cycles. The findings of the study revealed that the photocatalyst dosage and pH were the most influential factors in the effectiveness of lead removal. According to optimal conditions, lead removal reached a maximum of 96%. The results of this investigation showed that the synthetic photocatalyst, when exposed to UVA light, exhibited an extraordinary capacity for lead removal.

Mechanisms and Comparative Treatments of Allergic Rhinitis including Phototherapy

The treatment of allergic conditions presents a challenge for both seasonal allergic rhinitis and perennial rhinitis sufferers. The increasing prevalence of both of these types of allergic responses requires the use of a range of treatments which can provide relief. The treatment of allergic rhinitis has been considered under the ARIA (Allergic Rhinitis and its Impact on Asthma) guidelines. Current treatment options include medication and avoidance for those with reduced responses, but more expensive treatments include immunotherapy and the use of monoclonal antibodies (mAb). All treatments target specific parts of the inflammatory response which includes mast cells, eosinophils and basophils. Phototherapy can be a useful addition to these treatments, and combinations of UV-B (5%), UV-A (25%) and visible light (70%) in phototherapy treatments have been shown to reduce the severity of symptoms. Phototherapy consisting of visible wavelengths and infrared light (660 nm 940 nm) was shown to be particularly effective in treating perennial rhinitis. The use of a range of wavelengths in the control of allergic responses is described in this paper. Phototherapy can form part of an effective treatment regime for allergic rhinitis sufferers which can exploit synergies in the control of the condition elicited through several pathways.

Effect of photons of the far red region in the spectrum of LED radiation on the growth and development of sugar beet plants (Beta <i>vulgaris</i> L. ssp. <i>vulgaris</i> var. <i>saccharifera</i> Alef.)

Relevance and methodology. The task of controlling the growth and development of sugar beet plants with the help of lighting devices is of interest from the point of view of identifying biological features of the culture and in breeding practice. The purpose of the research is to determine the response of plants to the effects of low–energy monochrome radiation at the initial stage of ontogenesis (germination of seeds (coplodia) sugar beet). In this regard, the seeds of the hybrid Smena were germinated in the dark (control) and under different variants of continuous illumination with wavelengths of 380 nm, 440 nm, 525 nm, 660 nm and 730 nm.Results. The reaction of sugar beet seeds and sprouts to illumination with monochromatic light depends on the wavelength Germination of seeds when irradiated with monochromatic far-red light leads to a decrease in germination energy by 23%, seed germination by 39%, the height of sprouts and aboveground biomass by 21.8% compared with the control (dark germination). Similar indicators were observed for the negative effect of red light. Exposure to UV-A light (380 nm) led to an increase in germination energy by 4%, but germination, on the contrary, decreased by 12%. The terrestrial biomass of sprouts also decreased (by 9.9%). Irradiation with green and blue light had a positive effect on growth: the terrestrial biomass of sprouts increased by 19.8% with a green spectrum and 7.3% blue. At the same time, there was no decrease in germination energy and germination compared to the control. The germination energy under the influence of blue light even increased by 12%. With dark germination, elongated etiolated plants were formed on the 10th day, whereas in the variants of green, blue and UV-A irradiation, harmoniously developed dark green shoots were formed.

Industrial Application of AI-Based Assistive Magnetic Particle Inspection

Magnetic Particle Inspection (MPI) is one of the most used methods in Non-Destructive Testing (NDT), allowing precise and robust defect detection on industrial-grade manufactured parts. However, human controllers perform this task in full black environments under UV-A lighting only (with safety glasses) and use chemical products in a confined environment. Those constraints tends to lower control performance and increase stress and fatigue. As a solution, we propose an AI-based assistive machine (called “PARADES”) inside the hazardous environment, remotely manipulated by a human operator, outside of the confined area, in cleaner and safer conditions. This paper focuses on the development of a complete industrial-grade AI machine, both in terms of hardware and software. The result is a standalone assistive AI-based vision system, plug-and-play and controller-friendly, which only needs the usual power supply 230 V plug that detects defects and measures defect length. In conclusion, the PARADES machines address for the first time the problem of occupational health in MPI with an industrial standalone machine which can work on several parts and be integrated into current production lines. Providing cleaner and healthier working conditions for operators will invariably lead to increased quality of detection. These results suggest that it would be beneficial to spread this kind of AI-based assistive technology in NDT, in particular MPI, but also in Fluorescent Penetrant Testing (FPT) or in visual inspection.

Photochemical inactivation as an alternative method to produce a whole-cell vaccine for uropathogenic Escherichia coli (UPEC).

Lower urinary tract infection (UTI), caused primarily by uropathogenic Escherichia coli, represents a significant health burden, accounting for 7 million primary care and 1 million emergency room visits annually in the United States. Women and the elderly are especially susceptible and recurrent infection (rUTI) is common in those populations. Lower UTI can lead to life-threatening systemic infection. UTI burden is manifested by healthcare dollars spent (1.5 billion annually), quality of life impact, and resistant strains emerging from antibiotic overuse. A safe and effective vaccine to prevent rUTI would address a substantial healthcare issue. Vaccines comprised of inactivated uropathogenic bacteria have yielded encouraging results in clinical trials but improvements that enhance vaccine performance are needed. To that end, we focused on inactivation methodology and provided data to support photochemical inactivation, which targets nucleic acid, as a promising alternative to conventional protein-damaging inactivation methods to improve whole-cell UTI vaccines.

Heterogeneous Photocatalytic Oxidation and Detoxification of Simulated Agricultural Wastewater Contaminated with Boscalid Fungicide Using g-C3N4 Catalyst

In the present study, the photocatalytic oxidation and detoxification of aqueous matrices contaminated with boscalid using g-C3N4 catalyst and UV-A light was investigated. The UV-A/g-C3N4 process was found to achieve higher than 83% removal of boscalid in both matrices, with h+ and O2•− being the main species. UHPLC-HRMS analysis allowed the identification of five TPs, while the main degradation pathways involved hydroxylation, cyclization, and dechlorination. Scenedesmus rubescens microalgae species was exposed to boscalid solutions and lake water spiked with the fungicide before the photocatalytic treatment and inhibition in the growth rate was observed. An increase in the toxicity was also observed during the first stages of the treatment. The results from the in silico study correlate with the observed evolution of ecotoxicity during the application of the process, as some of the identified TPs were found to be toxic or very toxic for aquatic organisms. However, prolonged application of the process can lead to detoxification. It was also observed that the g-C3N4 catalyst can retain its photochemical stability and activity after at least three cycles. However, a slight decrease in the activity was observed when repeated another two times. This study demonstrated that the suggested photocatalytic process can both decrease the harmful effects of boscalid as well as effectively lower its concentration in water.

Combining Riboflavin/UV-A Light and Rose Bengal/Green Light Corneal Cross-Linking Increases the Resistance of Corneal Enzymatic Digestion.

The purpose of this study was to determine if concurrent riboflavin/UV-A light (RF/UV-A) and rose Bengal/green light (RB/green) epi-off PACK-CXL enhances corneal resistance to enzymatic digestion compared to separate chromophore/light treatments. Ex vivo porcine corneas were allocated as follows. Group A corneas were soaked with riboflavin (RF) and were either not irradiated (A1, controls) or were irradiated with 10 (A2) or 15 J/cm² (A3) UV-A light at 365nm, respectively. Group B corneas were soaked with RB and either not irradiated (B1, controls) or were illuminated with 10 (B2) or 15 J/cm² (B3) green light at 525nm, respectively. Corneas in group C were soaked with both RF and RB and were either not irradiated (C1, controls) or were subjected to the same session consecutive 10 J/cm2 (C2) or 15 J/cm2 (C3) UV-A and green light exposure. Following treatment, all corneas were exposed to 0.3% collagenase A to assess digestion time until corneal button dissolution. A1 to A3 digestion times were 21.38, 30.5, and 32.25hours, respectively, with A2 and A3 showing increased resistance to A1. B1-3 had digestion times of 31.2, 33.81, and 34.38hours, with B3 resisting more than B1. C1 to C3 times were 33.47, 39.81, and 51.94hours; C3 exhibited superior resistance to C1 and C2 (both P < 0.05). Same-session combined RF/UV-A and RB/green PACK-cross-linking significantly increases corneal enzymatic digestion resistance over standalone treatments. Combining RF-based and RB-based PACK-CXL considerably increases corneal collagenase digestion resistance, potentially minimizing ulcer size in clinical contexts.

Synthesis of 2-Amino-N'-aroyl(het)arylhydrazides, DNA Photocleavage, Molecular Docking and Cytotoxicity Studies against Melanoma CarB Cell Lines.

Diacylhydrazine bridged anthranilic acids with aryl and heteroaryl domains have been synthesized as the open flexible scaffold of arylamide quinazolinones in order to investigate flexibility versus rigidity towards DNA photocleavage and sensitivity. Most of the compounds have been synthesized via the in situ formation of their anthraniloyl chloride and subsequent reaction with the desired hydrazide and were obtained as precipitates, in moderate yields. All compounds showed high UV-A light absorption and are eligible for DNA photocleavage studies under this "harmless" irradiation. Despite their reduced UV-B light absorption, a first screening indicated the necessity of a halogen at the p-position in relation to the amine group and the lack of an electron-withdrawing group on the aryl group. These characteristics, in general, remained under UV-A light, rendering these compounds as a novel class of UV-A-triggered DNA photocleavers. The best photocleaver, the compound 9, was active at concentrations as low as 2 μΜ. The 5-Nitro-anthranilic derivatives were inactive, giving the opposite results to their related rigid quinazolinones. Molecular docking studies with DNA showed possible interaction sites, whereas cytotoxicity experiments indicated the iodo derivative 17 as a potent cytotoxic agent and the compound 9 as a slight phototoxic compound.

Effect of Ultraviolet Radiation on the Enzymolytic and Biomechanical Profiles of Abdominal Aortic Adventitia Tissue.

The abdominal aortic aneurysm (AAA) is defined as an increase in aortic diameter by more than 50% and is associated with a high risk of rupture and mortality without treatment. The aim of this study is to analyze the role of aortic adventitial collagen photocrosslinking by UV-A irradiation on the biomechanical profile of the aortic wall. This experimental study is structured in two parts: the first part includes in vitro uniaxial biomechanical evaluation of porcine adventitial tissue subjected to either short-term elastolysis or long-term collagenolysis in an attempt to duplicate two extreme situations as putative stages of aneurysmal degeneration. In the second part, we included biaxial biomechanical evaluation of in vitro human abdominal aortic adventitia and human AAA adventitia specimens. Biomechanical profiles were examined for porcine and human aortic tissue before and after irradiation with UV-A light (365 nm wavelength). On the porcine aortic sample, the enhancing effect of irradiation was evident both on the tissue subjected to elastolysis, which had a high collagen-to-elastin ratio, and on the tissue subjected to prolonged collagenolysis despite being considerably depleted in collagen. Further, the effect of irradiation was conclusively demonstrated in the human adventitia samples, where significant post-irradiation increases in Cauchy stress (longitudinal axis: p = 0.001, circumferential axis: p = 0.004) and Young's modulus (longitudinal axis: p = 0.03, circumferential axis: p = 0.004) were recorded. Moreover, we have a stronger increase in the strengthening of the AAA adventitia samples following the exposure to UV-A irradiation (p = 0.007) and a statistically significant but not very important increase (p = 0.021) regarding the stiffness in the circumferential axis. The favorable effect of UV irradiation on the strength and stiffness of degraded aortic adventitia in experimental situations mimicking early and later stages of aneurysmal degeneration is essential for the development and potential success of procedures to prevent aneurysmal ruptures. The experiments on human normal and aneurysmal adventitial tissue confirmed the validity and potential success of a procedure based on exposure to UV-A radiation.

Monitoring of UV-A radiation by TiO2/CdS nanohybrid along with the high on-off ratio

Exposure to UV-A light can have detrimental effects on human health, leading to skin damage and an increased risk of skin cancer. In this study, we employed a hydrothermal-assisted method to cultivate TiO2-decorated CdS nanorods for use in UV photodetectors. Our research culminated in the fabrication of an exceptionally responsive and rapid photodetector based on the TiO2/CdS nanohybrid. X-ray diffraction analysis revealed the hexagonal phase of CdS nanorods, predominantly oriented along the (002) plane, and the presence of the anatase phase of TiO2. Scanning electron microscopy (SEM) measurements confirmed the nanorod structure of TiO2/CdS. Optical properties of the TiO2/CdS nanohybrid were investigated through UV–visible absorbance analysis. Additionally, X-ray photoelectron spectroscopy (XPS) provided insights into the surface composition of the prepared nanohybrid, with peaks corresponding to Cd 3d3/2 and Cd 3d5/2 at binding energies of 411.47 eV and 404.73 eV, respectively, and confirming the presence of titanium through peaks of Ti 2p3/2 and 2p1/2 at binding energies of 458.31 eV and 463.8 eV, respectively. Raman analysis indicated the presence of the anatase phase of TiO2 in the composite. Our device exhibited an impressive detectivity of 9.9 × 1012 Jones, an EQE (external quantum efficiency) of 971.36%, and a high photoresponsivity of 2.86 A/W. These results suggest that TiO2/CdS nanohybrids, prepared using a cost-effective and straightforward method, hold promise for UV photodetection applications.

Photocatalytic degradation of ciprofloxacin by using tannin-doped BaTiO3 catalyst

The aim of this study is to highlight the significance of ciprofloxacin degradation, a commonly used antibiotic in healthcare and agriculture, by synthesizing tannin-doped BaTiO3 (T-Ba) photocatalysts at various tannin amounts (0–50 wt%) and investigating their photocatalytic activity under both UV-A light and visible light irradiation. The impact of several parameters, including the initial concentration of ciprofloxacin, photocatalyst dosage, initial solution pH, and scavengers effect, on the photocatalytic activity was explored. The photocatalysts were characterized by FTIR, SEM, XRD, XPS, TEM, BET, PL and UV-DRS analysis. In the conducted studies, it was observed that the highest efficiency was achieved at 96 % under appropriate parameters. The kinetic study was conducted based on the Langmuir-Hinshelwood equations. According to stability tests, ciprofloxacin degradation was found as 92 % after the second cycle, while it was 50 % after the fifth cycle.

A Continuous-Wave EPR Investigation into the Photochemical Transformations of the Chromium(I) Carbonyl Complex [Cr(CO)4bis(diphenylphosphino)]+ and Reactivity with 1-hexene.

Chromium complexes containing a bis(diphenylphosphino) ligand have attracted significant interest over many years due to their potential as active catalysts for ethylene oligomerisation when combined with suitable co-catalysts such as triethylaluminium (TEA) or methylaluminoxane (MAO). While there has been considerable attention devoted to the possible reaction intermediates and the nature of the Cr oxidation states involved, the potential UV photoactivity of the Cr(I) complexes has so far been overlooked. Therefore, to explore the photoinduced transformations of bis(diphenylphosphino) stabilized Cr(I) complexes, we used continuous-wave (CW) EPR to study the effects of UV radiation on a cationic [Cr(CO)4(dppp)]+[Al(OC(CF3)3)4]- complex (1), where dppp represents the 1,3 bis-(diphenylphosphino)propane ligand, Ph2P(C3H6)PPh2. Our preliminary investigations into the photochemistry of this complex revealed that [Cr(CO)4(dppp)]+ (1) can be readily photo-converted into an intermediate mer-[Cr(CO)3(κ1-dppp)(κ2-dppp)]+ complex (2) and eventually into a trans-[Cr(CO)2(dppp)2]+ complex (3) in solution at room temperature under UV-A light. Here, we show that the intermediate species (2) involved in this transformation can be identified by EPR at much lower temperature (140 K) and at a specific wavelength (highlighting the wavelength dependency of the reaction). In addition, small amounts of a 'piano-stool'-type complex, namely [Cr(CO)2(dppp-η6-arene)]+ (4), can also be formed during the photoconversion of [Cr(CO)4(dppp)]+ using UV-A light. There was no evidence for the formation of the [Cr(L-bis-η6-arene)]+ complex (5) in these UV irradiation experiments. For the first time, we also evidence the formation of a 1-hexene coordinated [Cr(CO)3(dppp)(1-hexene)]+ complex (6) following UV irradiation of [Cr(CO)4(dppp)]+ in the presence of 1-hexene; this result demonstrates the unprecedented opportunity for exploiting light activation during Cr-driven olefin oligomerisation catalysis, instead of expensive, difficult-to-handle, and hazardous chemical activators.

Atomically dispersed Mn sites on TiO2(B) microspheres enables efficient photocatalytic abatement of NOx

While photocatalytic technology has been recognized as an effective means for removing low-concentration NOx in ambient atmosphere, it still faces the challenge of the deep oxidation in high efficiency. In many cases, the release of more toxic NO2 byproduct appeared to be inevitable during the photocatalytic oxidation of NO. Herein we report that the atomically dispersed MnOx cocatalyst on TiO2(B) microspheres could significantly enhance the deep oxidation of NOx under mild photocatalytic conditions (1 mW/cm2 UV-A light, 1 L/min flow rate). At an initial NO concentration of 0.35 ppm, ca. 67.15% of NO is oxidized on the MT-0.5 sample, which is 2.76 times higher than the pristine TiO2(B) sample. More importantly, the release of NO2 is suppressed by 2.11 times. Comprehensive spectral analyses suggest that atomically dispersed MnOx effectively promotes the charge separation of photogenerated carriers in TiO2(B), even better than MnOx nanoparticles-loaded TiO2(B). EPR and in-situ FTIR analyses illustrate that atomically dispersed MnOx-loaded TiO2(B) sample exhibits excellent low concentration NOx abatement performance, thus providing a rational mechanism for the NO deep oxidation pathway. This study not only provides a unique approach for preparing non-noble metal atomically dispersed co-catalysts, but also affords an effective means for efficient photocatalytic NO degradation.

Fabrication of carbon dots-embedded luminescent transparent wood with ultraviolet blocking and thermal insulating capacities towards smart window application

To expand functions of transparent wood (TW) including fluorescence, ultraviolet blocking, heat preservation and insulation, we adopted carbon quantum dots (CQDs) to prepare luminescent transparent wood. CQDs with yellow/red fluorescence (YCD/RCD) were prepared by chitosan and o-phenylenediamine. Afterwards, Balsa woods were pretreated to obtain wood frameworks (DW/LW), which were further combined with epoxy resin for achieving transparent woods (DW-TW/LW-TW). Results showed LW retained more lignin, the LW-TW blocked more ultraviolet light, displaying the better visible transmission and mechanical strength than DW-TW. After adding YCD and RCD to LW-TW, the yellow and red fluorescence transparent woods with outstanding mechanical and ultraviolet blocking properties were prepared, especially the red fluorescence transparent wood (RTW). Specifically, the tensile strength and elongation at break of RTW reached up to 19.39 MPa and 5.35 %, respectively. Moreover, RTW could block 78.8 % of UV-B light and 78 % of UV-A light, respectively. Besides, RTW possessed excellent visible transmission (70.3 %) and UV blocking (88.87 %). Significantly, both RTW and YTW displayed outstanding water repellency, excellent durability, good thermal stability and insulation. Predictably, luminescent transparent woods certainly will enhance the adaptability of wood, and broaden its applications in green decoration, lighting setup, sensor and other fields.

Unravelling the activation mechanism of oxidants using copper ferrite nanopowder and its application in the treatment of real waters contaminated by phenolic compounds

Copper ferrites (CuFe2O4) nanopowder was prepared via hydrothermal method followed by annealing at 500 °C, and XRD, SEM, XPS and UPS were employed for its characterization. CuFe2O4 was tested for the catalytic degradation of bisphenol A (BPA) in the dark and under UVA light, both in the presence of peroxymonosulfate (PMS) or peroxydisulfate (PDS) as radical precursor under natural pH of 6.2. While the individual photo-induced processes i.e., photocatalysis (using CuFe2O4 alone) and photolysis of either PMS or PDS, exhibited limited efficiencies in BPA degradation, a significant increase of performance was observed by combining CuFe2O4 and UVA light with either PMS or PDS with a synergy effect of 3.8 and 34.1, respectively. Under the optimal conditions, employing 0.5 g/L of nanopowder, the degradation constant of 25 µM BPA was 0.211 min−1 with 2 mM of PMS and 0.018 min−1 with 2 mM of PDS, and resulted in the complete degradation of BPA within less than 20 min. The activation mechanism of PMS and PDS using CuFe2O4 was elucidated, revealing sulfate radicals as the primary reactive species in PMS-containing systems, whereas a predominantly non-radical pathway was observed in the presence of PDS. Indeed, advanced spectroscopic techniques indicated that surface copper played an important role in the non-radical pathway. Furthermore, the CuFe2O4/PMS/UVA system exhibited high performance in the degradation of different phenolic compounds including BPA, phenol and p-nitrophenol in real water matrices. These achievements were observed across different real water matrices with a particular emphasis on sewage treatment plant water.

Photocatalytic Reduction of VOCs with Ag/Ni-Doped Photocatalyst in Different Temperature and Humidity Environments

The photocatalytic oxidation (PCO) process is one of the most preferred, inexpensive, and environmentally friendly methods for VOC removal. It has been determined that this method can remove a wide range of organic pollutants. The removal of benzene and toluene pollutants, two important VOCs commonly encountered in flue gases, has been studied in the scope of this study using the photocatalytic oxidation method under UVA irradiation. For this purpose, the photocatalytic activity of the photocatalyst increased by the metal/metal doping process. Two different metals, a noble metal (Ag) and a transition metal (Ni), were used together for the doping of TiO2 nanoparticles, and the photocatalysts attached to a glass surface were prepared. Four different doping percentages were used for photocatalysts: 0.5%, 1%, 2.5%, and 5%. Several PCO experiments were conducted under different temperatures (120, 150, and 180 °C) and humidity conditions (25 and 50%). Photocatalytic oxidation experiments were carried out with artificially produced benzene and toluene gases, and the success of the system was evaluated with respect to removal efficiency calculations. The UVA light source was used for the photocatalytic experiments. The results of the study indicated that the removal efficiencies of toluene were found to be higher than those of benzene, and the most suitable conditions were determined to be 50% humidity and a 120 °C environment with the use of a 1% doped photocatalyst.

Uncovering the potential of yttrium doped zinc oxide nanoparticles as an efficient catalyst for photodegradation of recalcitrant pollutant and a contributor antibacterial property

This work focused on the development of photocatalytic and antibacterial ZnO doped nanoparticles for wastewater treatment application. ZnO nanoparticle was successfully doped via a sol-gel method with different concentration of yttrium (Y), a rare-earth element. The improved properties of the structural, optical, photocatalytic and antibacterial after the nanoparticles doping modification were analyzed. XRD analysis confirmed the hexagonal (wurtzite) structure with average crystalline size between 10 and 22.7 nm. The exhibited XRD peaks that shifted towards lower angles after doping confirmed the Y3+ substitution in the ZnO structures. High-resolution transmission electron microscopy (HRTEM) showed an increase in grain size as the concentration of Y3+ ions inside the ZnO matrix increased. Ultraviolet-visible-near-infrared spectroscopic measurement revealed a red shift of the bandgap energy of 0.128 eV, which confirmed the substitution process. It was observed that the Y-dopant significantly improved the photocatalytic activity of the ZnO nanoparticles; 91.8 %, 72.9 %, 29.2 % and 85.0 % of 20 ppm of humic acid, 20 ppm of BPA, 20 ppm of phenol and 20 ppm of caffeine respectively under UVA light irradiation. In addition, Y-doped ZnO nanoparticle was found to be highly effective against S. aureus as compared to E. coli. The 9 wt% Y-doped ZnO (9YZnO) nanoparticles have shown no bacterial growth at both minimum inhibitory concentration/minimum bacterial concentration MIC/MBC concentration which served as evidence of the improved antibacterial properties of the modified ZnO nanoparticles. Overall, in this study Y-doped ZnO nanoparticle had shown good performance as photocatalysis material in degrading organic compounds (natural, industrial and consumable organic compounds) and antibacterial material against germ positive microorganism. Considering the developed nanoparticle's performance, its application could be an efficient alternative for water and wastewater treatment applications.

Photoinactivation of the bacteriophage PhiX174 by UVA radiation and visible light in SM buffer and DMEM-F12

ObjectiveIt has been observed that viruses can be inactivated by UVA radiation and visible light. The aim of this study is to investigate whether a medium that contains a photosensitizer might have an influence on viral reduction under irradiation by UVA, violet or blue light. Test virus is the bacteriophage PhiX174 in the photosensitizer-free SM buffer and DMEM-F12, which contains the known photosensitizer riboflavin.ResultsThe determined PhiX174 D90 doses in SM buffer and DMEM were 36.8 J/cm² and 13.6 J/cm² at 366 nm, 153.6 J/cm² and 129.1 J/cm² at 408 nm and 4988 J/cm² and 2477.1 J/cm² at 455 nm, respectively. It can be concluded that the medium has a large influence on the results. This might be caused by the photosensitizer riboflavin in DMEM-F12. As riboflavin is a key component in many cell culture media, irradiation experiments with viruses in cell culture media should be avoided if the investigation of intrinsical photoinactivation properties of viruses is aimed for.

Main chain selective polymer degradation: controlled by the wavelength and assembly.

The advent of reversible deactivation radical polymerization (RDRP) revolutionized polymer chemistry and paved the way for accessing synthetic polymers with controlled sequences based on vinylic monomers. An inherent limitation of vinylic polymers stems from their all-carbon backbone, which limits both function and degradability. Herein, we report a synthetic strategy utilizing radical ring-opening polymerization (rROP) of complementary photoreactive cyclic monomers in combination with RDRP to embed photoresponsive functionality into desired blocks of polyvinyl polymers. Exploiting different absorbances of photoreactive cyclic monomers, it becomes possible to degrade blocks selectively by irradiation with either UVB or UVA light. Translating such primary structures of polymer sequences into higher order assemblies, the hydrophobicity of the photodegradable monomers allowed for the formation of micelles in water. Upon exposure to light, the nondegradable blocks detached yielding a significant reduction in the micelle hydrodynamic diameter. As a result of the self-assembled micellar environment, telechelic oligomers with photoreactive termini (e.g., coumarin or styrylpyrene) resulting from the photodegradation of polymers in water underwent intermolecular photocycloaddition to photopolymerize, which usually only occurs efficiently at longer wavelengths and a much higher concentration of photoresponsive groups. The reported main chain polymer degradation is thus controlled by the irradiation wavelength and the assembly of the polymers.

An in vitro cytotoxicity study on PANI/ZnO nanocomposites against HCT- 116 cancer cells using MTT assay

Polyaniline/ZnO nanocomposites were synthesized with different weight percentage of ZnO (20%, 40%, 60%, and 80%) using an in situ chemical polymerization method. The prepared composite samples were characterized by FT-IR, XRD, TEM, SEM with EDAX, UV-Vis, PL, electrical conductivity, photocatalytic properties, antibacterial and anticancer activity. The presence of functional groups in PANI-ZnO NCs is identified by FTIR spectral analysis. X-ray diffraction patterns show that the nanocomposites exhibit preferential orientational growth along the (002) plane with a hexagonal wurtzite structure. The intensity of the maximum reflection (101) increases with increasing ZnO doping concentrations. The TEM analysis indicates that the spherical shape,the particle size was found to be 36.8 nm. SAED pattern closely matched the peaks of the XRD pattern, confirming that the relevant SAED patterns correspond to hexagonal Wurtzite crystals of ZnO. SEM image shows a spherical morphology and ZnO nanoparticles are homogeniously mixed with PANI matrix. EDAX analysis showed the presence of Zn, C and O.UV-vis absorption spectra reveals increasing wavelength leads to the redshift in which there is a strong interaction between PANI and PANI/ZnO. The band gap energy of PANI/ZnO NCs is decreased to 1.30 eV by adding different concentrations of ZnO. PL analysis showed that the addition of ZnO dopants reduced the bandgap and increased oxygen defect vacancies of PANI/ZnO composites. An increase in ZnO content in the PANI matrix was also seen to cause a decrease in electrical conductivity. This alteration might be connected to ZnO’s doping and dedoping activity in the PANI matrix. Photocatalytic activity of 80 wt%ZnO-doped PANI-NPs through the degradation of methylene blue (MB) pigment studied under UV-A light and had detected 95% of degradation throughout 260 min. The lowest bandgap of 80 wt% ZnO shows the highest photocatalytic MB degradation performance. PANI/ZnO nanocomposite with high concentration of ZnO had good antibacterial activity against both P. aeruginosa and S. aureus. An in vitro study was used to evaluate the cytotoxic effects of PANI and PANI/ZnO NPs on the HCT-116 cell line. The results of the MTT test reveal that PANI/ZnO NPs have a significantly greater cytotoxic effect on the HCT-116 cell line than PANI.