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Photochemical & Photobiological Sciences

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https://www.readbyqxmd.com/read/28443924/investigations-on-the-photochromic-properties-of-2-6-bis-5-bromo-2-hydroxybenzylidene-cyclohexanone
#1
L N Corîci, S Shova, V Badea, D Aparaschivei, O Costisor, L Cseh
The network of chemical reactions of 2,6-bis(5-bromo-2-hydroxybenzylidene)cyclohexanone (BHBC) when subjected to light and different pH values has been investigated. The pH dependent species involved in the chemical network have been identified and characterized by NMR and UV-VIS spectroscopy. Direct pH jumps were carried out by adding a strong acid to equilibrated solutions of trans-chalcone (Ct) forming the flavylium cation which was stable only under extremely acidic conditions (pH < 0.5). The single crystal X-ray study and NMR analysis has confirmed the structure of the new flavylium cation...
April 26, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28443909/effect-of-the-calcination-temperature-on-the-photocatalytic-efficiency-of-acidic-sol-gel-synthesized-tio2-nanoparticles-in-the-degradation-of-alprazolam
#2
Andreia Romeiro, Diana Freitas, M Emília Azenha, Moisés Canle, Hugh D Burrows
We report a comparative study on the photodegradation of the widely used benzodiazepine psychoactive drug alprazolam (8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine, ALP) using direct photolysis, and titanium dioxide photocatalyzed reaction. Titanium dioxide photocatalysts were prepared as nanoparticles by acidic sol-gel methods, calcined at two different temperatures, and their behavior compared with P25 (Degussa type) TiO2. Efficient photodegradation was observed in the photocatalytic process, with over 90% degradation after 90 minutes under optimized conditions...
April 26, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28440831/systematic-investigations-on-fused-%C3%AF-system-compounds-of-seven-benzene-rings-prepared-by-photocyclization-of-diphenanthrylethenes
#3
Shota Fujino, Minoru Yamaji, Hideki Okamoto, Toshiki Mutai, Isao Yoshikawa, Hirohiko Houjou, Fumito Tani
We studied the photoproducts of 1-(n-phenanthryl)-2-(m-phenanthryl)ethenes (nEm; n, m = 1, 3 and 9) for understanding photocyclization patterns based on NMR spectroscopy. The crystal structures of the photoproducts were analyzed by X-ray crystallography, and the photophysical features of the photocyclized molecules were investigated based on emission and transient absorption measurements. Phenanthrene derivatives substituted at the 1- and 3-positions were prepared for synthesizing nEm by photocyclization of stilbene derivatives...
April 25, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28439592/one-pot-photoassisted-synthesis-in-situ-photocatalytic-testing-for-hydrogen-generation-and-the-mechanism-of-binary-nitrogen-and-copper-promoted-titanium-dioxide
#4
Sean Taylor, Mihir Mehta, Dmitri Barbash, Alexander Samokhvalov
For the sustainable production of hydrogen by photocatalysis, the use of renewable resources such as water, organic compounds from plant biomass and earth abundant metal promoters is desired. We herein describe the previously not reported "one-pot" photoassisted synthesis of a binary metal-nitrogen promoted Cu(0)-N-TiO2 photocatalyst from a N-TiO2 precursor by photodeposition of copper directly in the photocatalytic suspension. The N-TiO2 contains nanocrystalline anatase as found by XRD and Raman spectroscopy...
April 25, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28436496/effect-of-anthraquinone-2-6-disulfonate-on-the-photolysis-of-2-4-4-tribromophenylphenyl-ether
#5
Wei Yuan, Guining Lu, Yingying Xie, Kaibo Huang, Rui Wang, Hua Yin, Zhi Dang
In this study, we have investigated the photolysis of 2,4,4'-tribromophenylphenyl ether (BDE-28) in Triton X-100 (TX-100) solutions, and discussed the effect of anthraquinone-2,6-disulfonate (AQDS) on the photolysis of BDE-28. The effect of TX-100 on the photolysis of BDE-28 was mainly related to the concentration of TX-100. The fastest photolysis of BDE-28 was at 500 mg L(-1) of the TX-100 solution, and the corresponding photolysis rate constant was 0.12 min(-1). The direct photolysis rate of BDE-28 decreased from 0...
April 24, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28430271/theoretical-modulation-of-singlet-triplet-chemiexcitation-of-chemiluminescent-imidazopyrazinone-dioxetanone-via-c8-substitution
#6
L Pinto da Silva, C M Magalhães, D M A Crista, J C G Esteves da Silva
Coelenterazine, a member of the imidazopyrazinone class of chemiluminescent substrates, presents significant potential as a dynamic probe of reactive oxygen species in a biological environment, such as a superoxide anion, in which these species are important in cellular biology and pathology. The objective of the current study was to understand in what way the efficiency of singlet and triplet chemiexcitation could be modulated, towards a more efficient use of imidazopyrazinone-based compounds as dynamic chemiluminescent probes...
April 21, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28397920/cooperative-effects-of-o-and-m-methyl-groups-on-the-intramolecular-charge-transfer-emission-properties-of-dibenzoylmethanatoboron-difluorides
#7
Mirai Tanaka, Shunsuke Muraoka, Yasunori Matsui, Eisuke Ohta, Takuya Ogaki, Kazuhiko Mizuno, Hiroshi Ikeda
The photophysical properties of o-tolyl-, m-tolyl-, and p-xylyl-substituted asymmetric diaroylmethanatoboron difluorides in a mixture of CH2Cl2 and c-C6H12, and in the crystalline state were determined. In solution, the fluorescence (FL) properties of these substances are controlled by the position and number of methyl groups on the phenyl rings. An especially interesting finding is that FL from the p-xylyl derivative occurs from an excited state which possesses intramolecular charge-transfer character caused by the o- and m-methyl groups cooperatively...
April 11, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28383082/outstanding-reviewers-for-photochemical-photobiological-sciences-in-2016
#8
EDITORIAL
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No abstract text is available yet for this article.
April 6, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28382337/physiochemical-properties-of-greatly-enhanced-photoluminescence-of-aqueous-dispersible-upconversion-caf2-yb-er-nanoparticles
#9
Anees A Ansari, Ranvijay Yadav, S B Rai
Crystal phase morphological structure and optical properties of the as-prepared upconversion CaF2:Yb/Er(core) and sequential coating of an inert crystalline material and silica layers surrounding the seed core-nanoparticles (NPs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), optical absorption, FTIR spectroscopy and upconversion photoluminescence spectroscopy. Owing to the unique properties of CaF2 host matrix, we realized their practical applications in biomedical science to improve the upconversion luminescence property and aqueous dispersibility...
April 6, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28379273/effect-of-nucleants-in-photothermally-assisted-crystallization
#10
T Shilpa, Sajan D George, Aseefhali Bankapur, Santhosh Chidangil, Aditya K Dharmadhikari, Deepak Mathur, S Madan Kumar, K Byrappa, Abdul Ajees Abdul Salam
Laser-induced crystallization is emerging as a promising technique to crystallize biomolecules like amino acids and proteins. The use of external materials as nucleants and novel seeding methods open new paths for protein crystallization. We report here the results of experiments that explore the effect of nucleants on laser-based crystallization of microlitre droplets of small molecules, amino acids, and proteins. The role of parameters like solute concentration, droplet volume, type and size of the nucleant, and laser power, are systematically investigated...
April 5, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28379265/a-light-harvesting-perylene-derivative-zinc-phthalocyanine-complex-in-water-spectroscopic-and-thermodynamic-studies
#11
Ahmed El-Refaey, Shaban Y Shaban, Maged El-Kemary, Mohamed E El-Khouly
A perylene derivative, namely N,N'-bis(2(trimethylammonium iodide)ethylene)perylene-3,4,9,10-tetracarboxyldiimide (TAIPDI) forms nanoscale columnar stacks in water that have been characterized by using optical absorption and emission measurements, dynamic light scattering (DLS), and transmission electron microscopy (TEM). This behaviour was compared with that of unstacked TAIPDI in methanol. Assembly formation between the one-dimensional TAIPDI stacks and zinc phthalocyanine tetrasulphonic groups (ZnPcS4) via strong π-π and ionic interactions has been described in an aqueous medium...
April 5, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28379252/violet-blue-light-activates-nrf2-signaling-and-modulates-the-inflammatory-response-of-thp-1-monocytes
#12
L A Trotter, D Patel, S Dubin, C Guerra, V McCloud, P Lockwood, R Messer, J C Wataha, J B Lewis
Several studies suggest that light in the UVA range (320-400 nm) activates signaling pathways that are anti-inflammatory and antioxidative. These effects have been attributed to Nrf2-mediated upregulation of "phase 2" genes such as heme oxygenase-1 (HO-1) that neutralize oxidative stress and metabolize electrophiles. Proteomics analysis previously had shown that small doses of blue light (400-500 nm) increased levels of peroxiredoxin phase 2 proteins in THP-1 monocytes, which led to our hypothesis that blue light activates Nrf2 signaling and thus may serve as an anti-inflammatory agent...
April 5, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28374036/dependence-of-the-hydration-status-of-bacterial-light-harvesting-complex-2-on-polyol-cosolvents
#13
Ying Shi, Jie Yu, Long-Jiang Yu, Peng Wang, Li-Min Fu, Jian-Ping Zhang, Zheng-Yu Wang-Otomo
Low molecular weight (MW) polyols are organic osmolytes influencing protein structure and activity. We have intended to investigate the effects of low MW polyols on the optical and the excited-state properties of the light-harvesting complex 2 (LH2) isolated from the photosynthetic bacterium Thermochromatium (Tch.) tepidum, a thermophile growing at ∼50 °C. Steady state spectroscopy demonstrated that, on increasing glycerol or sorbitol fractions up to 60% (polyol/water, v/v), the visible absorption of carotenoids (Crts) remained unchanged, while the near infrared Qy absorption of bacteriochlorophyll a (BChl) at 800 nm (B800) and 850 nm (B850) varied slightly...
April 4, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28374035/critical-appraisal-of-data-used-to-infer-record-uvi-in-the-tropical-andes
#14
R L McKenzie, J B Liley, S Madronich
When the data sets that suggested record high UVI values at Mt Licancabur, and Laguna Blanca, Bolivia are reviewed in full, we find that the reported peak values are incorrect, probably due to instrumental problems. These affect the UVB, UVA and PAR channels at different times and different solar zenith angles, with distinct diurnal patterns in each case. The outliers are consistent with errors that would result from build-up of ice or snow on the surface of the entrance dome, combined with incomplete baffling of light within the integrating spheres that form the entrance optic of these instruments, but we cannot unequivocally attribute them to this cause...
April 4, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28352922/luminescence-spectroscopy-of-chalcogen-substituted-rhodamine-cations-in-vacuo
#15
Mark H Stockett, Christina Kjær, Michelle K Linder, Michael R Detty, Steen Brøndsted Nielsen
Intrinsic optical properties of several rhodamine cations were probed by measuring their dispersed fluorescence spectra in vacuo. Three different rhodamine structures were investigated, each with four different chalcogen heteroatoms. Fluorescence band maxima were blue-shifted by between 0.15 and 0.20 eV (1200-1600 cm(-1)) relative to previous solution-phase measurements. Trends in emission wavelengths and fluorescence quantum yields previously measured in solution are generally reproduced in the gas phase, confirming the intrinsic nature of these effects...
March 29, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28349142/high-performance-multifunctional-green-co3o4-spinel-nanoparticles-photodegradation-of-textile-dye-effluents-catalytic-hydrogenation-of-nitro-aromatics-and-antibacterial-potential
#16
S K Jesudoss, J Judith Vijaya, P Iyyappa Rajan, K Kaviyarasu, M Sivachidambaram, L John Kennedy, Hamad A Al-Lohedan, R Jothiramalingam, Murugan A Munusamy
Tricobalt tetraoxide (Co3O4), a spinel-structured nanoparticle which possesses mixed oxidation states, has been synthesized via a Punica granatum (P. granatum, pomegranate) seed extract-mediated green reaction and has been investigated for its superior catalytic activity in three applications, which include (i) photodegradation of textile dye effluents (TDE) collected from the dyeing industry, Tiruppur, Tamil Nadu, India, (ii) catalytic hydrogenation of nitro-aromatic pollutants such as 4-nitrophenol and 4-nitroaniline, and (iii) antibacterial potential in biomedical applications...
March 28, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28345701/the-effect-of-natural-iron-oxide-and-oxalic-acid-on-the-photocatalytic-degradation-of-isoproturon-a-kinetics-and-analytical-study
#17
H Boucheloukh, W Remache, F Parrino, T Sehili, H Mechakra
The photocatalytic degradation of isoproturon, a persistent toxic herbicide, was investigated in the presence of natural iron oxide and oxalic acid and under UV irradiation. The influence of the relevant parameters such as the pH and the iron oxide and oxalic acid concentrations has been studied. The presence of natural iron oxide and oxalic acid in the system effectively allow the degradation of isoproturon, whereas the presence of t-butyl alcohol adversely affects the phototransformation of the target pollutant, thus indicating that an OH radical initiated the degradation mechanism...
March 27, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28332693/an-electron-transfer-photochromic-crystalline-mof-accompanying-photoswitchable-luminescence-in-a-host-guest-system
#18
Yu-Shuang Liu, Yu-Hui Luo, Li Li, Hong Zhang
A new electron transfer type photoactive host-guest supramolecule was constructed by introducing (CH3)2NH2(+) cations to the MOF framework. The resulting compound 1 exhibits reversible photochromic property without using photochromic components, resulting from photoinduced electron-transfer between the electron-rich anionic framework and the electron-deficient guest ions. In addition, a photoluminescence "on/off switch" occurs during the coloration-decoloration process. The raw materials are non-poisonous and harmless, hence compound 1 may be more cost-effective, clean, and harmless to the heath than existing photochromic materials...
March 23, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28304067/lipid-remodelling-in-human-melanoma-cells-in-response-to-uva-exposure
#19
Elisabete Maciel, Juliana Felgueiras, Eduarda M P Silva, Fernando Ricardo, Ana S P Moreira, Tânia Melo, Ana Campos, Margarida Fardilha, Pedro Domingues, M Rosário Domingues
Extensive exposure to UVA is thought to increase the risk of malignancy and the progression of melanoma, the most serious type of skin cancer. It is well known that alterations in lipid metabolism represent an early event in carcinogenesis, but the impact of UVA exposure on the lipid composition of cancer cells is still largely unknown. In this study we aimed at investigating lipid remodeling in human melanoma cells in response to UVA exposure. After UVA irradiation, lipid extracts were either immediately collected from SK-MEL-28 cells or collected after a recovery period of 2 h or 24 h...
March 17, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28294270/ultra-weak-photon-emission-in-healthy-subjects-and-patients-with-type-2-diabetes-evidence-for-a-non-invasive-diagnostic-tool
#20
Meina Yang, Wenyu Ding, Yanli Liu, Hua Fan, Rajendra P Bajpai, Jialei Fu, Jingxiang Pang, Xiaolei Zhao, Jinxiang Han
BACKGROUND: Spontaneous ultra-weak photon emission (UPE) is a common phenomenon in biological systems and has been linked to pathological states. Researchers have always considered ultra-weak photon emission a potential non-invasive diagnostic tool, but its application in the medical field is stagnant due to the lack of relevant data for pathological states. METHODS: Ultra-weak photon signals from five body sites (forehead, neck, heart, stomach, and navel) in fifty patients with type 2 diabetes and sixty age-matched healthy subjects were measured using a moveable whole-body biophoton detection system...
March 15, 2017: Photochemical & Photobiological Sciences
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