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Photochemical & Photobiological Sciences

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https://www.readbyqxmd.com/read/28332693/an-electron-transfer-photochromic-crystalline-mof-accompanying-photoswitchable-luminescence-in-a-host-guest-system
#1
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
#2
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
#3
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
https://www.readbyqxmd.com/read/28287658/variability-in-chlorophyll-fluorescence-spectra-of-eggplant-fruit-grown-under-different-light-environments-a-case-study
#4
Brian Ospina Calvo, Tamara L Parapugna, M Gabriela Lagorio
The main goal of the present work was to clarify physiological strategies in plants whose chloroplasts were developed under different light environments. The specific objective was to elucidate the influence of the spectral distribution of light on the chlorophyll fluorescence ratio and on photosynthetic parameters. To achieve this purpose, three species of eggplant fruit (black, purple and white striped and white) were used as a case study and their chlorophyll fluorescence was analyzed in detail. Spectra of the non-variable fluorescence in each part of the fruit were corrected for distortions by light reabsorption processes using a physical model...
March 13, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28287657/phototransformation-of-5-nitro-2-furaldehyde-in-aqueous-solution-a-laser-flash-photolysis-and-product-analysis-study
#5
Luis J A Martins, João M M Ferreira
Laser flash photolysis of 5-nitro-2-furaldehyde (NFA) in solution shows a short-lived transient absorption with λmax = 475 ± 5 nm, which is relatively insensitive to solvent polarity and is assigned to the lowest triplet state of NFA ((3)NFA*). In water, the (3)NFA* absorption decays to a long-lived absorption, the study of which, at different times after the end of the laser pulse, reveals it to be due to a furyloxyl radical (λmax ≈ 375 nm) and to the radical anion NFA˙(-) (λmax ≈ 400 nm). These radicals were produced independently to confirm the assignment...
March 13, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28287230/experimental-and-computational-characterization-of-photosensitized-conformational-effects-mediated-by-protoporphyrin-ligands-on-human-serum-albumin
#6
Jie Hu, Ryan Allen, Sarah Rozinek, Lorenzo Brancaleon
When investigating the interaction between proteins and protoporphyrins in aqueous solution, one typically has to contend with the tendency of the latter to form polydispersed aggregates. The interference of aggregated protoporphyrins manifests, at least, at two levels: aggregates sequester the majority of the protoporphyrin molecules in solution and prevent their interaction with the proteins, but also their presence interferes with optical experiments such as absorption and fluorescence spectroscopy. In this study we present a protocol which uses dialysis and centrifugation to eliminate the aggregates and yield solutions dominated by non-covalent complexes of albumin (HSA) and protoporphyrins...
March 13, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28281718/quantum-yield-for-the-photo-degradation-of-vitamin-d3
#7
Arjan van Dijk
Ultraviolet radiation can photodegrade vitamin D3 to suprasterol I, superasterol II and 5,6-transvitamin D3. The probability of the photodegradation of vitamin D3, after the absorption of one photon, is called the quantum yield. We estimated the quantum yield ϕ for all the degeneration reactions together on the basis of the results reported by Webb et al. (1989) for a degradation experiment on pure, tritiated vitamin D3 in methanol in sunlight. We find ϕ = (0.42 ± 0.1). This value of the quantum yield can be used to estimate the kinetics contribution from vitamin D3 degradation in exposure experiments and model calculations...
March 10, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28272628/solvent-dependent-dual-luminescence-properties-of-a-europium-complex-with-helical-%C3%AF-conjugated-ligands
#8
Yuichi Kitagawa, Ryohsuke Ohno, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
A europium(iii) complex with a large π-conjugated helical ligand, tris(hexafluoroacetylacetonato)europium(iii)bis((pentahelicenyl)diphenylphosphine oxide) (Eu(hfa)3(HPO)2), exhibits dual luminescence excited at the π-π* transition band. In this study, the solvent-dependent photophysical properties of Eu(hfa)3(HPO)2 are reported. The ground-state properties of the ligand and the Eu(iii) complex are assessed from electronic absorption spectra, magnetic circular dichroism spectra, and density functional theory calculations...
March 8, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28267158/photo-reorganization-of-3-alkoxy-6-chloro-2-benzo-b-thiophen-2-yl-4h-chromen-4-ones-a-green-and-convenient-synthesis-of-angular-pentacyclics
#9
Aarti Dalal, Radhika Khanna, Parvin Kumar, Ramesh C Kamboj
Photo-reorganization of 3-alkoxy-6-chloro-2-(benzo[b]thiophen-2-yl)-4H-chromen-4-ones in methanol with Pyrex filtered UV-light from a medium pressure 125 W Hg-vapor lamp led to the formation of angular pentacyclic compounds (dihydro and aromatic products) along with some rearranged chromenones where the product(s) distribution depended upon the structure of 3-alkoxy groups (methoxy, ethoxy, allyloxy and benzyloxy). The phenyl moiety in the 3-benzyloxy group had a profound effect on the dihydro product(s) formation as the latter was in high yield when the alkoxy group was benzyloxy followed by allyloxy, ethoxy and methoxy groups...
March 7, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28243650/structure-and-electronics-in-dimeric-boron-%C3%AF-expanded-azine-and-salphen-complexes
#10
Laura A Crandall, Mahesh B Dawadi, Tailon Burrell, Adwoa Odoom, Christopher J Ziegler
Although boron-based fluorophores incorporating nitrogenous chelating ligands have received much attention, there has been little work on examples of boron-salphen and azine derivatives. In this report, we present several π expanded boron salphen type complexes, incorporating both bis(2-hydroxynaphthaldehyde)azine as well as ortho, meta and para variants of the analogous 2-hydroxynaphthaldehyde salphen compounds. For the azine, we observed only the formation of a single BF2 adduct, while for the naphth-phen compounds dimeric BF2 binding was observed...
February 28, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28225114/the-new-supramolecular-nano-aggregate-curcumin-cucurbit-7-uril-synthesis-photophysical-properties-and-biocompatibility-evaluation
#11
Leandro Araújo de Azevedo, Leonis Lourenço da Luz, Jamylle Nunes de Souza Ferro, Emiliano Barreto, Ricardo Oliveira Silva, Severino Alves, Iane Bezerra Vasconcelos Alves
The supramolecular nano-aggregate CUR-CB[7] (CUR = curcumin and CB[7] = cucurbit[7]uril) was efficiently prepared by mixing CUR and CB[7] at a molar ratio of 1 : 1 in ethanol at room temperature. The supramolecular aggregate formation was evidenced by mainly FTIR, (1)H NMR, DOSY and spectroscopy experiments. The supramolecular arrangement promotes the increase in the solubility and stability of CUR without affecting the biological properties of the A549 cells. The luminescence properties of CUR and CUR-CB[7] show anti-Kasha's rule fluorescence, and their remarkable NIR emission enables this material to be used as a luminescent probe and marker for in vivo tracking and structural integrity monitoring of the supramolecular complex...
February 22, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28210728/self-initiation-of-uv-photopolymerization-reactions-using-tetrahalogenated-bisphenol-a-meth-acrylates
#12
Théophile Pelras, Wolfgang Knolle, Sergej Naumov, Katja Heymann, Olesya Daikos, Tom Scherzer
The potential of tetrachlorinated and tetrabrominated bisphenol A diacrylates and dimethacrylates for self-initiation of a radical photopolymerization was investigated. The kinetics of the photopolymerization of an acrylic model varnish containing halogenated monomers was studied by real-time FTIR spectroscopy, whereas the formation of reactive species and secondary products was elucidated by laser flash photolysis and product analysis by GC-MS after steady-state photolysis. The interpretation of the experimental data and the analysis of possible reaction pathways were assisted by quantum chemical calculations...
February 17, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28203671/heat-shock-antagonizes-uva-induced-responses-in-murine-melanocytes-and-melanoma-cells-an-unexpected-interaction
#13
Leonardo Vinícius Monteiro de Assis, Maria Nathália Moraes, Ana Maria de Lauro Castrucci
The skin is under the influence of oscillatory factors such as light and temperature. This organ possesses a local system that controls several aspects in a time-dependent manner; moreover, the skin has a well-known set of opsins whose function is still unknown. We demonstrate that heat shock reduces Opn2 expression in normal Melan-a melanocytes, while the opposite effect is found in malignant B16-F10 cells. In both cell lines, UVA radiation increases the expression of Opn4 and melanin content. Clock genes and Xpa, a DNA repair gene, of malignant melanocytes are more responsive to UVA radiation when compared to normal cells...
February 16, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28186216/absolute-configuration-determination-through-the-unique-intramolecular-excitonic-coupling-in-the-circular-dichroisms-of-o-p-ddt-and-o-p-ddd-a-combined-experimental-and-theoretical-study
#14
Hiroki Tanaka, Yoshihisa Inoue, Takeshi Nakano, Tadashi Mori
Circular dichroisms (CDs) of the o,p'-isomers of 1,1,1-trichloro- and 1,1-dichloro-2,2-bis(chlorophenyl)ethanes (DDT and DDD) were investigated experimentally and theoretically. A series of strong Cotton effect peaks in a characteristic negative-negative-positive-negative, or its mirror-imaged, pattern were observed in the CD spectra of these persistent organic pollutants. The theoretical CD spectra at the SAC-CI/B95(d) and RI-CC2/def2-TZVPP levels well reproduced the experimental ones, enabling us to unambiguously assign the absolute configuration of (+)-DDT and (-)-DDD as S...
February 10, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28165094/exfoliation-and-supramolecular-functionalization-of-graphene-with-an-electron-donor-perylenediimide-derivative
#15
Luis Martín-Gomis, Nikos Karousis, Fernando Fernández-Lázaro, Ioannis D Petsalakis, Kei Ohkubo, Shunichi Fukuzumi, Nikos Tagmatarchis, Ángela Sastre-Santos
The liquid exfoliation of graphite to few layered graphene sheets together with the non-covalent supramolecular functionalization of exfoliated graphene by the synthesized N,N'-di(2-ethylhexyl)-1-(N''''-methylpiperazin-N'''-yl)perylene-3,4,9,10-tetracarboxydiimide (Pip-PDI) is reported. The aromatic Pip-PDI has the ability to non-covalently interact with the exfoliated graphene sheets, stabilizing them and preventing their reassembly. On the other hand, the presence of the piperazine moiety on the bay position of the PDI core makes it an ideal electron donor, nicely coupled with the electron accepting exfoliated graphene, hence, forming a novel donor-acceptor nanoensemble, which was characterized by complementary spectroscopic and microscopy techniques...
February 6, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28155961/homoleptic-complexes-of-a-porphyrinatozinc-ii-2-2-6-2-terpyridine-ligand
#16
Angelo Lanzilotto, Martin Kuss-Petermann, Oliver S Wenger, Edwin C Constable, Catherine E Housecroft
Three homoleptic complexes containing the metalloligand 7-(4-([2,2':6',2''-terpyridin]-4'-yl)phenyl)-5,10,15,20-tetraphenylporphyrinatozinc(ii), 1, have been prepared. [Zn(1)2][PF6]2, [Fe(1)2][PF6]2 and [Ru(1)2][PF6]2 were characterized by (1)H and (13)C NMR spectroscopy and mass spectrometry, and the electrochemical and photophysical properties of the complexes have been investigated. In solution, each complex undergoes two reversible porphyrin-centred oxidation processes, with an additional reversible metal-centred oxidation for [Fe(1)2][PF6]2 and [Ru(1)2][PF6]2...
February 3, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28154871/introduction-to-the-themed-issue-the-health-benefits-of-uv-radiation-exposure-through-vitamin-d-production-or-non-vitamin-d-pathways
#17
EDITORIAL
Prue H Hart, Mary Norval, Vivienne E Reeve
No abstract text is available yet for this article.
February 3, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28150847/ylidenemalononitrile-enamine-coated-media-as-fluorescent-turn-on-probes-for-volatile-primary-amines
#18
Ashley R Longstreet, Rebecca R Chandler, Tanmay Banerjee, L Zane Miller, Kenneth Hanson, D Tyler McQuade
Two ylidenemalononitrile enamines, adsorbed to various media, undergo a cyclization reaction with primary amine vapors resulting in a fluorometric and colorimetric response. After determining the media with the fastest response rate for emission "turn-on" to be aluminum oxide activated neutral (AON), we further demonstrate the sensitivity (propylamine concentrations as low as 200 ppm are detected) and selectivity to various analytes including amines, methanol, and ethanethiol. Lastly, as an alternative means of detection, the colorimetric response dye on glass filter paper was shown to detect propylamine concentrations as low as 29 ppm...
February 2, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28145542/a-spectroscopic-study-of-the-excited-state-proton-transfer-processes-of-8-bromo-7-hydroxyquinolin-2-yl-methyl-protected-phenol-in-aqueous-solutions
#19
Jinqing Huang, Adna P Muliawan, Jiani Ma, Ming De Li, Hoi Kei Chiu, Xin Lan, Davide Deodato, David Lee Phillips, Timothy M Dore
A combination of spectroscopic methods and density functional theory (DFT) computations was used to study the excited state proton transfer (ESPT) processes of (8-bromo-7-hydroxyquinolin-2-yl)methyl-protected phenol (BHQ-OPh). Characterization of the prototropic forms of BHQ-OPh in different solvent environments revealed that the neutral form predominates in acetonitrile and in 1 : 1 acetonitrile/water (pH 5.0), whereas the anionic form predominates in 1 : 1 acetonitrile/PBS (pH 7.4). Both the neutral and anionic forms were significantly populated in 1 : 1 acetonitrile/water...
February 1, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28139795/sunlight-exposure-is-just-one-of-the-factors-which-influence-vitamin-d-status
#20
M Abboud, M S Rybchyn, R Rizk, D R Fraser, R S Mason
Studies on the determinants of vitamin D status have tended to concentrate on input - exposure to ultraviolet B radiation and the limited sources in food. Yet, vitamin D status, determined by circulating concentrations of 25-hydroxyvitamin D (25(OH)D), can vary quite markedly in groups of people with apparently similar inputs of vitamin D. There are small effects of polymorphisms in the genes for key proteins involved in vitamin D production and metabolism, including 7-dehydrocholesterol reductase, which converts 7-dehydrocholesterol, the precursor of vitamin D, to cholesterol, CYP2R1, the main 25-hydroxylase of vitamin D, GC, coding for the vitamin D binding protein which transports 25(OH)D and other metabolites in blood and CYP24A1, which 24-hydroxylates both 25(OH)D and the hormone, 1,25-dihydroxyvitamin D...
January 31, 2017: Photochemical & Photobiological Sciences
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