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Photochemical & Photobiological Sciences

Silvia M Zacarías, Silvana Pirola, Agustina Manassero, María E Visuara, Orlando M Alfano, María L Satuf
The photocatalytic inactivation of Bacillus subtilis spores in air was evaluated employing a fixed-bed reactor with TiO2-coated glass rings, under artificial UV-A radiation. Calculations of the radiation effectively absorbed inside the reactor were carried out by Monte Carlo simulations. The photocatalytic inactivation was assessed by analyzing the viability of the microorganisms retained by the coated glass rings inside the reactor at different irradiation periods. The initial concentration of the spores was reduced by almost 55% at the end of the experiment (12 h)...
November 14, 2018: Photochemical & Photobiological Sciences
Lukasz Sobotta, Daniel Ziental, Justyna Sniechowska, Jolanta Dlugaszewska, Marek J Potrzebowski
Photodynamic inactivation potential against bacteria of four chlorin derivatives with phenyl or fluorophenyl substituents was evaluated. The quantum yield values of singlet oxygen formation were in the range of 0.16-0.86. Compounds were characterized by high quantum yields of fluorescence (0.15-0.44) and moderate photostability in DMF solutions. Irradiation of chlorins in DMSO resulted in their phototransformation and then photodecomposition. Photodynamic inactivation of bacteria was performed after the compounds had been loaded into lipid vesicles...
November 14, 2018: Photochemical & Photobiological Sciences
Panchada Ch V Govindu, Basavaprabhu Hosamani, Smriti Moi, Dhananjeyan Venkatachalam, Sabreddy Asha, Varun N John, V Sandeep, Konkallu Hanumae Gowd
Avobenzone is the most widely used UVA filter in sunscreen lotion and it is prone to degradation in the presence of sunlight/UV radiation. To overcome the photo-instability of avobenzone, various photostabilizers have been used as additives, including antioxidants such as vitamin C, vitamin E, and ubiquinone. In the present study, the well known antioxidant, glutathione, was evaluated for protecting avobenzone from photodegradation in the presence of glass-filtered sunlight. The features of glutathione as a skin whitener and a radical scavenger in cells have prompted the assessment of the photostabilzing activity of glutathione on avobenzone...
November 13, 2018: Photochemical & Photobiological Sciences
Yeraldith Rojas Pérez, Roberto Etchenique
A visible-light activatable caged compound based on a ruthenium-polypyridine complex was used to elicit the feeding response of the freshwater cnidarian Hydra vulgaris. The phototrigger delivers l-arginine in a clean reaction under irradiation with blue or green light. The synthesis, characterization and application mode of this caged arginine are described. A combination of fiber-optics setup and a high absorbance medium allows the precise control of uncaging in the submillimetric range, needed to address the zone where activation takes place...
November 13, 2018: Photochemical & Photobiological Sciences
Javier Moreno-Andrés, Rubén Rios Quintero, Asunción Acevedo-Merino, Enrique Nebot
The development of advanced photochemical processes has experienced the emergence of a promising alternative for water disinfection, different from traditional methods. The applicability has primarily been investigated in drinking and wastewater; however, new challenges related to microbiological control in marine waters necessitate evaluating the applicability of this process in such water matrices. In this study, the efficacy of persulfate (PDS) activated with UV-light against E. faecalis has been tested on the bench scale...
November 9, 2018: Photochemical & Photobiological Sciences
Kaiqi Xu, Athanasios Chatzitakis, Ingvild Julie Thue Jensen, Mathieu Grandcolas, Truls Norby
Ta3N5 nanotubes (NTs) were obtained from nitridation of Ta2O5 NTs, which were grown directly on Ta foil through a 2-step anodization procedure. With Co(OH)x decoration, a photocurrent density as high as 2.3 mA cm-2 (1.23 V vs. NHE) was reached under AM1.5G simulated solar light; however, the electrode suffered from photocorrosion. More stable photoelectrochemical (PEC) performance was achieved by first loading Co(OH)x, followed by loading cobalt phosphate (Co-Pi) as double co-catalysts. The Co(OH)x/Co-Pi double co-catalysts may act as a hole storage layer that slows down the photocorrosion caused by the accumulated holes on the surface of the electrode...
November 9, 2018: Photochemical & Photobiological Sciences
Yung-Chung Chen, Yuan-Tsung Kuo, Tsung-Han Ho
A series of p-substituted NPG derivatives (Cl-NPG, OMe-NPG and NO2-NPG) comprising different push-pull characteristics have been synthesized and characterized. The NPG derivatives have good thermal stability and red shifted absorption when compared with the original N-phenyl glycine (NPG) compound. These NPGs were selected in combination with 2-chlorohexaaryl biimidazole (o-Cl-HABI) for Type II free radical polymerization (FRP). Commercial NPG was also mixed with o-Cl-HABI for comparison. Their photo-polymerization properties were investigated by the gel fraction method in a nitrogen atmosphere...
November 9, 2018: Photochemical & Photobiological Sciences
Yulia I Meteleshko, Alexander V Nemukhin, Maria G Khrenova
The iLOV protein is a promising member of the class of flavin mononucleotide (FMN) based fluorescent proteins (FbFPs). It is becoming a popular tool for bioanalytical applications and bioimaging as a competitor of the well-known green fluorescent protein and its analogues. The main limitation of FbFPs is that all the members have close values of their absorption and emission band maxima. Therefore the upcoming challenge is to introduce novel variants of FbFPs to extend their color palette. We report the results of computational studies of iLOV variants, introducing point mutations and chromophore analogues...
November 7, 2018: Photochemical & Photobiological Sciences
Soorya Sasi, Sunish K Sugunan, P Radhakrishnan Nair, K R V Subramanian, Suresh Mathew
The advanced lifestyle of the human race involves heavy usage of various gadgets which require copious supplies of energy for uninterrupted functioning. Due to the ongoing depletion of fossil fuels and the accelerating demand for other energy resources, renewable energy sources, especially solar cells, are being extensively explored as viable alternatives. Flexible solar cells have recently emerged as an advanced member of the photovoltaic family; the flexibility and pliability of these photovoltaic materials are advantageous from a practical point of view...
November 6, 2018: Photochemical & Photobiological Sciences
Jin Yeong Yun, Ju Byeong Chae, Mingeun Kim, Mi Hee Lim, Cheal Kim
A novel multiple target sensor, (E)-5-((4-(diethylamino)-2-hydroxybenzyldene)amino)-1H-imidazole-4-carboxamide (DHIC), was synthesized for fluorescence detection of Zn2+ and S2- and colorimetric detection of Fe3+/2+ in aqueous media. DHIC can operate as a turn "on-off" sequential fluorescent sensor for Zn2+ and S2-. Detection limits (1.59 μM and 8.03 μM) for Zn2+ and S2- are below the WHO standards (76.0 μM and 14.7 μM). The DHIC-Zn2+ complex could be reversibly reused with ethylenediaminetetraacetic acid...
November 6, 2018: Photochemical & Photobiological Sciences
Frank R de Gruijl, Ron Wolterbeek, Stan Pavel, Johan W de Fijter, Neveen A T Hamdy, Jan Nico Bouwes Bavinck
Low serum 25-hydroxyvitamin D (25OHD) concentrations have been associated with increased cancer risk, but the relative importance of seasonality, i.e. high summer concentrations versus low winter concentrations, is unclear. We investigated this issue in a high risk group: kidney transplant recipients with known increased risk of cancer and low vitamin D statuses. We examined the relationship between registered concentrations of 25OHD binned by quarter and subsequent risk of internal malignancy or cutaneous squamous cell carcinoma in 1112 kidney transplant recipients...
November 6, 2018: Photochemical & Photobiological Sciences
Ekaterina A Kozlova, Mikhail N Lyulyukin, Dina V Markovskaya, Dmitry S Selishchev, Svetlana V Cherepanova, Denis V Kozlov
Novel photocatalysts for CO2 reduction, which consist of a cadmium and zinc sulfide solid solution (Cd1-xZnxS), were successfully prepared by a simple two-step technique. The photocatalysts were characterized by X-ray diffraction, UV-VIS diffuse reflectance spectroscopy, and low-temperature N2 adsorption techniques and were tested in the gas-phase photocatalytic reduction of CO2 under visible light (λ = 450 nm). All the synthesized Cd1-xZnxS solid solutions were capable of enabling the chemical transformations of CO2 under the conditions considered...
November 2, 2018: Photochemical & Photobiological Sciences
Vladimir Heiskanen, Michael R Hamblin
Correction for 'Photobiomodulation: lasers vs. light emitting diodes?' by Vladimir Heiskanen and Michael R. Hamblin, Photochem. Photobiol. Sci., 2018, 17, 1003-1017.
October 31, 2018: Photochemical & Photobiological Sciences
Ulrike Just, Gabriele Hinterhuber, Robert Knobler, Reinhard Neumann
BACKGROUND AND OBJECTIVE: Pyogenic granuloma is a common benign vascular lesion of the skin and mucosa prone to ulceration and bleeding. Current therapeutic approaches include surgical excision, removal by means of electro caustic therapy, cryotherapy, and ablation with CO2 or vascular lasers. The purpose of this study was to investigate the efficacy of a 532 nm potassium-titanyl-phosphate laser (KTP-laser) for the treatment of pyogenic granulomas in terms of efficacy, advantages in clinical outcome, technique and associated side effects...
October 31, 2018: Photochemical & Photobiological Sciences
Fabienne Dumoulin
No abstract text is available yet for this article.
October 30, 2018: Photochemical & Photobiological Sciences
M Di Paolo, M J Roberti, A V Bordoni, P F Aramendía, A Wolosiuk, M L Bossi
We prepared water soluble, biocompatible fluorescent turn-on pH nanosensors and characterized their behavior as a function of changes in pH. The response relies on a halochromic reaction of a spirorhodamineamide derived from the bright and highly chemically and photo-stable rhodamine 6G, encapsulated in core/nanoporous shell silica nanoparticles. The fluorescent sensors displayed a fast response in the pH range of intracellular compartments. The encapsulation conferred solubility in aqueous environments and biocompatibility...
October 30, 2018: Photochemical & Photobiological Sciences
Prashantha Kumar T K M, Ashok Kumar S K
In the present work, new visible-light-active nanosized Ag2S-ZnS loaded on cellulose (AZCE) was synthesized by a precipitation method. The AZCE composite was systematically characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area, and UV-visible diffuse reflectance spectroscopy (UV-DRS). The activities of the photocatalysts were evaluated for rhodamine B dye (RhB) degradation under simulated sunlight and the amounts of the dye samples were analysed using a UV-vis spectrophotometer at λmax 554 nm...
October 26, 2018: Photochemical & Photobiological Sciences
Mark Wainwright
The use of a separate nomenclature for the application of photosensitisers to the oncological and infectious disease fields represents a sensible approach. There is commonality, of course, in that both utilise light activation and act via the local generation of reactive oxygen species, but the difference in cellular targets is so great that different designs are required to achieve proper selectivity for a clinical end use, whether in human or veterinary medicine. The following represents a personal view, and perhaps a clarification of terms, in what might be considered a major etymological dichotomy existing within photodynamic research, on the 20th anniversary of "PACT"...
October 26, 2018: Photochemical & Photobiological Sciences
Eric M Tippmann, Seja Culpepper, Wade Bunnel, Nolan Appel
A photochemically chemically active noncanonical amino acid para-azido-l-phenylalanine widely used in biology was found to be metabolized by Saccharomyces cerevisiae. Contrary to multiple reports, the azide moiety is not reduced to the corresponding amine. The amino acid's concentration was found to decline somewhat with time which was due, at least in part, to modification of the amino acid side chain. The metabolite was found to be photochemically active and further characterization concluded the azide moiety was still intact...
October 25, 2018: Photochemical & Photobiological Sciences
Dumitru Sirbu, Rebecca Wales, David R Geary, Paul G Waddell, Andrew C Benniston
A reasonable gram quantity of the crystalline red dye 7-phenylbenzo[a]phenazine-5(7H)-one (PBP) was synthesised by the condensation of N-phenylbezene-1,2-diamine with 2-hydroxynaphthalene-1,4-dione in acetic acid (58% yield). The molecular structure of the dye, as determined by single-crystal X-ray crystallography, reveals a near planar phenazinone-like core, and an N-phenyl group twisted out of this plane by around 85°. The CO bond length of 1.241(2) Å is consistent with double bond character, which supports minor ground state zwitterionic character to the compound...
October 25, 2018: Photochemical & Photobiological Sciences
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