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Photochemistry and Photobiology

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https://www.readbyqxmd.com/read/28425091/marine-bioluminescence-measurement-by-a-classical-light-sensor-and-related-foraging-behaviour-of-a-deep-diving-predator
#1
Jade Vacquié-Garcia, Jérôme Mallefet, Frédéric Bailleul, Baptiste Picard, Christophe Guinet
Bioluminescence is produced by a broad range of organisms for defense, predation or communication purposes. Southern elephant seal (SES) vision is adapted to low intensity light with a peak sensitivity, matching the wavelength emitted by myctophid species, one of the main prey of female SES. A total of 11 satellite-tracked female SES were equipped with a Time-Depth-Light 3D-accelerometers (TDR10-X) in order to assess whether bioluminescence could be used by SES to locate their prey. First, we demonstrated experimentally that the TDR10-X light sensor was sensitive enough to detect natural bioluminescence; however, we highlighted a low distance detection of the sensor...
April 20, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28391638/construction%C3%A2-of-er-3-yalo3-rgo-tio2-hybrid-electrode-with%C3%A2-enhanced%C3%A2-photoelectrocatalytic%C3%A2-performance%C3%A2-in-methylene%C3%A2-blue%C3%A2-degradation%C3%A2-under%C3%A2-visible%C3%A2-light
#2
Xian Zhou, Jun Zhang, Yue Ma, Hanqing Cheng, Shaozhu Fu, Dandan Zhou, Shuangshi Dong
Much attention has been paid on doping TiO2 to narrow its band gap to promote the absorption of visible light and restrain the recombination of electron-hole pairs to improve its efficiency in photoelectrocatalysis (PEC) under visible light irradiation. However, the oxidation potential energy of photo-induced holes for the modified catalysts by visible light excitation is lower than that without modification by UV excitation. In this work, we synthesized a co-coupled TiO2 electrode (denoted ERT) with the Er(3+) :YAlO3 and reduced graphene oxide (RGO), achieving the synergetic effect of visible-light-to-UV up conversion and response and great electron transfer ability...
April 9, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28391637/synthesis-photophysics-and-pdt-evaluation-of-mono-di-tri-and-hexa-peg-chlorins-for-pointsource-photodynamic-therapy
#3
Tobias Bornhütter, Ashwini A Ghogare, Annegret Preuß, Alexander Greer, Beate Röder
Pointsource photodynamic therapy (PSPDT) is a newly developed fiber optic method aimed at the delivery of photosensitizer, light and oxygen to a diseased site. Because of a need for developing photosensitizers with desirable properties for PSPDT, we have carried out a synthetic, photophysical and phototoxicity study on a series of PEGylated sensitizers. Chlorin and pheophorbide sensitizers were readily amenable to our synthetic PEGylation strategy to reach triPEG and hexaPEG galloyl pheophorbides and mono-, di-, triPEG chlorins...
April 9, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28391608/mechanistic-analysis-of-fluorescence-quenching-of-reduced-nicotinamide-adenine-dinucleotide-by-oxamate-in-lactate-dehydrogenase-ternary-complexes
#4
Huo-Lei Peng, Robert Callender
Fluorescence of Reduced Nicotinamide Adenine Dinucleotide (NADH) is extensively employed in studies of oxidoreductases. A substantial amount of static and kinetic work has focused on the binding of pyruvate or substrate mimic oxamate to LDH•NADH where substantial fluorescence quenching is typically observed. However, the quenching mechanism is not well understood limiting structural interpretation. Based on time-dependent density functional theory (TDDFT) computations with cam-B3LYP functional in conjunction with the analysis of previous experimental results, we propose that bound oxamate acts as an electron acceptor in the quenching of fluorescence of NADH in the ternary complex, where a charge transfer (CT) state characterized by excitation from the highest occupied molecular orbital (HOMO) of the nicotinamide moiety of NADH to the lowest unoccupied molecular orbital (LUMO) of oxamate exists close to the locally excited (LE) state involving only the nicotinamide moiety...
April 9, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28380699/the-evaluation-of-non-invasive-measurements-of-erythema-as-a-potential-surrogate-for-dna-damage-in-repetitively-uv-exposed-human-skin
#5
Sharon A Miller, Sergio G Coelho, Yuji Yamaguchi, Vincent J Hearing, Janusz Z Beer, Frank de Gruijl
Erythema (i.e. visible redness) and DNA damage caused by ultraviolet radiation (UVR) in human skin have similar action spectra and show good correlation after a single exposure to UVR. We explored the potential to use instrumental assessments of erythema as a surrogate for DNA damage after repeated exposures to UVR. We exposed 40 human subjects to three different exposure schedules using two different UVR sources. Cyclobutane pyrimidine dimers (CPDs) in skin biopsies were measured by immunofluorescence and erythema was assessed by both the Erythemal Index (EI) and the Oxy-hemoglobin (Oxy-Hb) content...
April 5, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28380692/on-the-simulation-of-two-dimensional-electronic-spectroscopy-of-indole-containing-peptides
#6
Angelo Giussani, Jacopo Marcheselli, Shaul Mukamel, Marco Garavelli, Artur Nenov
A benchmark study of low-cost multi-configurational CASSCF/CASPT2 schemes for computing the electronic structure of indole is presented. This facilitates the simulation of near-ultraviolet (UV) pump visible (VIS) probe (i.e. two-color) two-dimensional electronic spectra (2DES) of homo- and hetero-aggregates as well as for processing of multiple snapshots from molecular dynamics simulations. Fingerprint excited state absorption signatures of indole are identified in a broad spectral window between 10 and 25 kcm(-1) ...
April 5, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28380687/ftir-analysis-of-a-light-driven-inward-proton-pumping-rhodopsin-at-77-k
#7
Shota Ito, Shinya Sugita, Keiichi Inoue, Hideki Kandori
Parvularcula oceani xenorhodopsin (PoXeR) is a light-driven inward proton pump that was discovered from deep ocean marine bacteria. PoXeR is categorized into the same family of Anabaena sensory rhodopsin (ASR) that functions as a photochromic sensor. In this paper, we applied light-induced difference Fourier-transform infrared (FTIR) spectroscopy to PoXeR at 77 K, and the obtained spectra were compared with those of ASR. The structure and structural changes in the primary processes of PoXeR are common to all microbial rhodopsins...
April 5, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28380684/effectiveness-of-photodynamic-therapy-in-elimination-of-hpv-16-and-hpv-18-associated-with-cin-i-in-mexican-women
#8
Elizabeth Maldonado Alvarado, M Olivia Osorio Peralta, Alejandra Moreno Vázquez, L Alejandra Martínez Guzmán, M Eugenia Melo Petrone, Z Iveth Enriquez Mar, D Estela Jovel Galdamez, Bárbara Carrión Solana, Guadalupe Balderas Martínez, Eduarda Parra, R Inés Castellanos Oliveros, R Linda Bello Leiva, Araceli Espinosa Montesinos, Citlalli Barrera Mendoza, S Eugenia Medina García, Eva Ramón Gallegos
The present study aimed to determine the effectiveness of photodynamic therapy (PDT), using δ-aminolevulinic acid (5-ALA), in the elimination of premalignant cervical lesions in Mexican patients with human papillomavirus (HPV) infection and/or cervical intraepithelial neoplasia (CIN). Thirty women diagnosed with CIN I and/or positive for HPV participated in the study. Topical 6% 5-ALA in gel form was applied to the uterine cervix; after 4 h, the lesion area was irradiated with a light dose of 200 J/cm(2) at 635 nm...
April 5, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28380663/fluorescence-sensor-with-a-new-on-1-off-on-2-switching-mechanism-using-the-excited-state-intermolecular-proton-transfer-reaction-of-an-anthracene-diurea-compound
#9
Hisato Matsumoto, Yoshinobu Nishimura, Tatsuo Arai
A new photoreaction mechanism of "Three-state molecular switch" fluorescence sensor based on ON(1) -OFF-ON(2) sequence, was achieved by anthracene-diurea compound, which was designed by using two phenylurea groups and one anthracene, 9,10BtDSPUA. Photochemical properties of 9,10BtDSPUA and interaction between 9,10BtDSPUA and anion were investigated in detail by absorption, (1) H NMR, fluorescence and fluorescence decay measurements. While the fluorescence of 9,10BtDSPUA in DMSO (ON(1) ) was quenched in the presence of low concentration of acetate anion (OFF), fluorescence enhancement occurred by the addition of high concentration of acetate anion (ON(2) )...
April 5, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28374889/targeting-photochemical-scalpels-or-lancets-in-the-pdt-field-the-photochemist-s-role
#10
Stefano Protti, Angelo Albini, Radhika Viswanathan, Alexander Greer
This review covers photochemical approaches aimed at supplementing surgical instruments with hand-held photodynamic therapy (PDT) instruments. PDT is not widely used in hospitals, because of the laser equipment and expertise needed, and because insurance policies often do not cover the procedure. Accordingly, this review focuses on advances in photochemistry, photophysics, nanotechnology and miniaturization techniques that may likely inspire the use of hand-held instruments in PDT. A takeaway point is that the advent of photochemical scalpels or lancets that deliver reactive oxygen species (ROS) on site may better equip medical practitioners and allow for eradication of tumors or infections in general...
April 4, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28370264/novel-osmium-based-coordination-complexes-as-photosensitizers-for-panchromatic-photodynamic-therapy
#11
Savo Lazic, Pavel Kaspler, Ge Shi, Susan Monro, Tariq Sainuddin, Sarah Forward, Kamola Kasimova, Robie Hennigar, Arkady Mandel, Sherri McFarland, Lothar Lilge
Cancer remains a major global malaise requiring the advent of new, efficient, and low-cost treatments. Photodynamic therapy, which combines a photosensitizer and photons to produce cytotoxic reactive oxygen species, has been established as an effective cancer treatment but has yet to become mainstream. One of the main limitations has been the paucity of photosensitizers that are effective over a wide range of wavelengths, can exert their cytotoxic effects in hypoxia, are easily synthesized, and produce few if any side effects...
April 3, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28329421/naproxen-inhibits-uvb-induced-basal-cell-and-squamous-cell-carcinoma-development-in-ptch1-skh-1-hairless-mice
#12
Sandeep C Chaudhary, Mohammad Waseem, Mehtab Rana, Hui Xu, Levy Kopelovich, Craig A Elmets, Mohammad Athar
Naproxen possesses anti-proliferative and pro-apoptotic effects besides its known anti-inflammatory functions. Here, we demonstrate the anti-cancer effects of naproxen against UVB-induced BCCs and SCCs in a highly susceptible murine model of UVB carcinogenesis. Naproxen significantly inhibited UVB-induced BCCs and SCCs in this model. Tumor number and volume were significantly decreased (p<0.005 and p<0.05, respectively). Inhibition in UVB-induced SCCs and BCCs was 77% and 86%, respectively, which was associated with reduced PCNA and cyclin D1 and increased apoptosis...
March 22, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28303596/the-phototoxic-potential-of-the-flavonoids-taxifolin-and-quercetin
#13
Alena Rajnochová Svobodová, Alena Ryšavá, Michaela Psotová, Pavel Kosina, Bohumil Zálešák, Jitka Ulrichová, Jitka Vostálová
Quercetin, one of the most abundant polyphenols in the plant kingdom has been shown to be photodegraded on exposure to UV light. Despite the fact, it is a component of several dermatological preparations. Its phototoxic potential has not been evaluated to date. The aim of this study was to assess whether photo-induced degradation of quercetin is linked to phototoxic effects on living cells. Its dihydro derivative, taxifolin was included in the study. For evaluation, the 3T3 Neutral Red Uptake Phototoxicity Test according to OECD TG 432, was used...
March 16, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28295380/photochemical-immobilization-of-polymers-on-a-surface-controlling-film-thickness-and-wettability
#14
Gregory T Carroll, Nicholas J Turro, Angela Mammana, Jeffrey T Koberstein
In this manuscript we demonstrate the control of film thickness and surface wettability in the photochemical immobilization of poly (vinyl alcohol) (PVA) to a self-assembled monolayer (SAM) containing a phthalimide chromophore. Surface attachment is characterized by ellipsometry and contact angle measurements. The wettability of the resulting films is shown to depend on the chemical composition of the polymer. The film thickness is shown to depend on the irradiation time and molecular weight of the polymer...
March 15, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28295378/calcium-control-of-the-sign-of-phototaxis-in-brown-algal-gametes-of-mutimo-cylindricus
#15
Nana Kinoshita, Chikako Nagasato, Taizo Motomura
Brown algal swarmers usually exhibit positive or negative phototaxis. Such behaviours influence the increasing or decreasing dispersal distance or colonization on the new substratum. We confirmed that the sign of phototaxis (negative or positive) in male gametes of Mutimo cylindricus was affected by extracellular Ca(2+) influx through Ca(2+) channels. Under the control condition (10(-2) M [Ca(2+) ]), male gametes swimming with a helical rotation of their cell body mostly showed positive phototaxis. At 10(-3) M [Ca(2+) ], more than half of the male gametes showed positive phototaxis, whereas the others showed negative phototaxis...
March 15, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28295364/melanoma-chemoprevention-current-status-and-future-prospects
#16
Gagan Chhabra, Mary Ann Ndiaye, Liz Mariely Garcia-Peterson, Nihal Ahmad
The incidence of skin cancers, both non-melanoma as well as melanoma, are increasing in the United States. The ultraviolet radiation, mainly from sun, is considered the major cause for these neoplasms. While non-melanoma skin cancers are far more numerous, melanoma remains the most challenging. This is because melanoma can become extremely aggressive and its incidence is increasing worldwide due to lack of effective early detection, as well as disease recurrence, following both surgery and chemotherapy. Therefore, in addition to better treatment options, newer means are required to prevent melanomas from developing...
March 15, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28294346/skin-erythema-pigmentation-and-hydration-kinetics-after-ultraviolet-radiation-induced-photodamage-in-southern-chinese-women
#17
MiaoJian Wan, Rong Hu, Xiaoyuan Xie, Zijian Gong, Jinling Yi, Haiyan Chen, Lin Xie, Xiaomin Guan, Lei Guan, Wei Lai
Although there have been some studies about changes of skin erythema and pigmentation following ultraviolet radiation in other races, the relevant data in Chinese have never been achieved. Thus we evaluated the long-time course of skin erythema, pigmentation and hydration changes after different doses of solar-simulated ultraviolet (SSUV) irradiation in 26 Chinese women for 168 days. The erythema index increased abruptly and peaked during 3 days of SSUV exposure, then slowly returned to the baseline level starting at day 7 and completely recovered during 168-day course of this study only in one minimal erythema doses (MED) SSUV irradiation...
March 15, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28261814/ceo2-bi2-wo6-heterostructured-microsphere-with-excellent-visible-light-driven-photocatalytic-performance-for-degradation-of-tetracycline-hydrochloride
#18
Fengjun Zhang, Shuang Zou, Tianye Wang, Yuxi Shi, Peng Liu
CeO2 /Bi2 WO6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines were successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO2 /Bi2 WO6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi2 WO6 in both the degradation of Tetracycline hydrochloride (TCH) and Rhodamine B (RhB) under visible-light irradiation. The 1CeO2 /2Bi2 WO6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60min reaction...
March 6, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28247408/elucidation-of-binding-mechanism-of-photodynamic-therapeutic-agent-toluidine-blue-o-with-chicken-egg-white-lysozyme-by-spectroscopic-and-molecular-dynamics-studies
#19
Shanmugaraj Krishnamoorthy, Umadevi Palanivel, Senthilkumar Lakshmipathi, Ilanchelian Malaichamy
The nature of binding mechanism of toluidine blue O (TBO) with chicken egg white lysozyme was studied comprehensively by various spectroscopic and computational methods. Both steady state and time resolved fluorescence studies unambiguously point to the prevalence of static quenching mechanism in lysozyme-TBO system. Thermodynamic parameters revealed that the association of TBO with lysozyme was a spontaneous process in which hydrophobic and hydrogen bond interactions played a pivotal role in the binding process...
March 1, 2017: Photochemistry and Photobiology
https://www.readbyqxmd.com/read/28199743/novel-bi2-wo6-coupled-fe3-o4-magnetic-photocatalysts-preparation-characterization-and-photodegradation-of-tetracycline-hydrochloride
#20
Tianye Wang, Shuang Zhong, Shuang Zou, Fuhuan Jiang, Limin Feng, Xiaosi Su
Novel Bi2 WO6 coupled Fe3 O4 magnetic photocatalysts with excellent and stable photocatalytic activity for degrading tetracycline hydrochloride and RhB were successfully synthesized via a facile solvothermal route. Through the characterization of the as-prepared magnetic photocatalysts by XRD, SEM, TEM, XPS, UV-vis diffuse reflectance spectra, it was found that the as-prepared magnetic photocatalysts were synthesized by the coupling of Bi2 WO6 and Fe3 O4 , and introduction of appropriated Fe3 O4 can improved nanospheres morphology and visible-light response...
February 15, 2017: Photochemistry and Photobiology
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