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https://www.readbyqxmd.com/read/29161778/highly-efficient-destruction-of-squamous-carcinoma-cells-of-the-head-and-neck-by-photochemical-internalization-of-ranpirnase
#1
Nora Liebers, Tim Holland-Letz, Mona Welschof, Anders Høgset, Dirk Jäger, Michaela A E Arndt, Jürgen Krauss
Introduction: Photochemical Internalization is a novel drug delivery technology for cancer treatment based on the principle of Photodynamic Treatment. Using a photosensitizer that locates in endocytic vesicles membranes of tumor cells, Photochemical internalization enables cytosolic release of endocytosed antitumor agents in a site-specific manner. The purpose of the present in-vitro study was to explore whether Photochemical Internalization is able to enhance the efficacy of Ranpirnase, a cytotoxic amphibian ribonuclease, for eradication of squamous cell carcinoma of the head and neck...
November 2017: Journal of Experimental Therapeutics & Oncology
https://www.readbyqxmd.com/read/29161461/ruthenium-crosslinked-hydrogels-with-rapid-visible-light-degradation
#2
Teresa Rapp, Chris Highley, Brian Manor, Jason Burdick, Ivan J Dmochowski
Incorporation of photoresponsive molecules within soft materials can provide spatiotemporal control over bulk properties, and address challenges in targeted delivery and mechanical variability. However, the kinetics of in situ photochemical reactions are often slow and typically employ ultraviolet wavelengths. Here, we present a novel photoactive crosslinker Ru(bipyridine)2(3-pyridinaldehyde)2 (RuAldehyde), which was reacted with hydrazide-functionalized hyaluronic acid to form hydrogels capable of encapsulating protein cargo...
November 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29159355/aggregation-induced-visible-light-absorption-makes-reactant-1-2-diisocyanoarenes-act-as-photosensitizers-in-double-radical-isocyanide-insertions
#3
Wenmin Wang, Xiaoyang Sun, Jian Qu, Xiaoyu Xie, Zheng-Hang Qi, Daocheng Hong, Su Jing, Dong Zheng, Yuxi Tian, Haibo Ma, Shouyun Yu, Jing Ma
The joint computational and experimental efforts reveal that the organic molecule 1,2-diisocyano-4,5-dimethylbenzene (1) acts as both a reactant and a photosensitizer (PS) in a metal-free reaction with perfluoroalkylhalide (2) to produce 2-perfluoroalkyl quinoxalines (3) under visible light. Both the π-π stacking aggregation in crystals and the solvation in various solvents of PS 1 exhibited visible-light absorption at 466 nm in spite of its smaller coefficient than that of the ultraviolet-light absorption...
November 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29159349/near-field-chemical-mapping-of-gold-nanostructures-using-a-functionalized-scanning-probe
#4
C Dab, C Awada, A Merlen, A Ruediger
We report on photochemical and photophysical properties produced by Surface Plasmon Resonance (SPR) on metallic nanograins by means of high resolution Functionalized Tip-Enhanced Raman Spectroscopy (F-TERS). This technique relies on a sharp gold tip functionalized with Raman-active molecules to be scanned relatively to plasmonic hot-spots on a surface. We describe the local variation of plasmon-induced Raman enhancement on the surface of nanostructures that also affects the photochemistry while the quantitative interpretation of peak intensities requires the consideration of surface topography near the tip apex...
November 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29158847/photoactive-poly-3-hexylthiophene-nanoweb-for-optoelectrical-stimulation-to-enhance-neurogenesis-of-human-stem-cells
#5
Kisuk Yang, Jin Young Oh, Jong Seung Lee, Yoonhee Jin, Gyeong-Eon Chang, Soo Sang Chae, Eunji Cheong, Hong Koo Baik, Seung-Woo Cho
Optoelectrical manipulation has recently gained attention for cellular engineering; however, few material platforms can be used to efficiently regulate stem cell behaviors via optoelectrical stimulation. In this study, we developed nanoweb substrates composed of photoactive polymer poly(3-hexylthiophene) (P3HT) to enhance the neurogenesis of human fetal neural stem cells (hfNSCs) through photo-induced electrical stimulation. METHODS: The photoactive nanoweb substrates were fabricated by self-assembled one-dimensional (1D) P3HT nanostructures (nanofibrils and nanorods)...
2017: Theranostics
https://www.readbyqxmd.com/read/29157970/vertical-characteristics-of-vocs-in-the-lower-troposphere-over-the-north-china-plain-during-pollution-periods
#6
Jie Sun, Yuesi Wang, Fangkun Wu, Guiqian Tang, Lili Wang, Yinghong Wang, Yuan Yang
In recent years, photochemical smog and gray haze-fog have frequently appeared over northern China. To determine the spatial distribution of volatile organic compounds (VOC) during a pollution period, tethered balloon flights were conducted over a suburban site on the North China Plain. Statistical analysis showed that the VOCs concentrations peaked at the surface, and decreased with altitude. A rapid decrease appeared from the surface to 400 m, with concnetrations of alkanes, alkenes, aromatics and halocarbons decreasing by 48...
November 17, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/29156648/tuning-the-photoluminescence-of-graphene-quantum-dots-by-photochemical-doping-with-nitrogen
#7
Xiaofen Xu, Fuhua Gao, Xiaohua Bai, Fuchi Liu, Wenjie Kong, Ming Li
Nitrogen-doped graphene quantum dots (NGQDs) were synthesized by irradiating graphene quantum dots (GQDs) in an NH₃ atmosphere. The photoluminescence (PL) properties of the GQDs and the NGQDs samples were investigated. Compared with GQDs, a clear PL blue-shift of NGQDs could be achieved by regulating the irradiating time. The NGQDs obtained by irradiation of GQDs for 70 min had a high N content of 15.34 at % and a PL blue-shift of about 47 nm. This may be due to the fact that photochemical doping of GQDs with nitrogen can significantly enhance the contents of pyridine-like nitrogen, and also effectively decrease the contents of oxygen functional groups of NGQDs, thus leading to the observed obvious PL blue-shift...
November 20, 2017: Materials
https://www.readbyqxmd.com/read/29156245/changes-in-activities-of-both-photosystems-and-the-regulatory-effect-of-cyclic-electron-flow-in-field-grown-cotton-gossypium-hirsutum-l-under-water-deficit
#8
Xiao-Ping Yi, Ya-Li Zhang, He-Sheng Yao, Ji-Mei Han, Wah Soon Chow, Da-Yong Fan, Wang-Feng Zhang
To clarify the influence of water deficit on the functionality of the photosynthetic apparatus of cotton plants, leaf gas exchange, chlorophyll a fluorescence, and P700 redox state were examined in field-grown cotton Gossypium hirsutum L. cv. Xinluzao 45. In addition, we measured changes in the P515 signal and analyzed the activity of ATP synthase and the trans-thylakoid proton gradient (ΔpH). With increasing water deficit, the net CO2 assimilation rate (AN) and stomatal conductance (gs) significantly decreased, but the maximum quantum efficiency of PSII photochemistry (Fv/Fm) did not change...
November 10, 2017: Journal of Plant Physiology
https://www.readbyqxmd.com/read/29155908/iminium-and-enamine-catalysis-in-enantioselective-photochemical-reactions
#9
You-Quan Zou, Fabian M Hörmann, Thorsten Bach
Although enantioselective catalysis under thermal conditions has been well established over the last few decades, the enantioselective catalysis of photochemical reactions is still a challenging task resulting from the complex enantiotopic face differentiation in the photoexcited state. Recently, remarkable achievements have been reported by a synergistic combination of organocatalysis and photocatalysis, which have led to the expedient construction of a diverse range of enantioenriched molecules which are generally not easily accessible under thermal conditions...
November 20, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/29155553/thiyl-radical-based-charge-tagging-enables-sterol-quantitation-via-mass-spectrometry
#10
Sarju Adhikari, Yu Xia
Inspired by the high reactivity and specificity of thiyl radicals toward alkenes, we have developed a new charge derivatization method to enable fast and quantitative analysis of sterols via electrospray ionization-mass spectrometry (ESI-MS). Thioglycolic acid (TGA), a commercially available compound, has been established as a highly efficient tagging reagent. Initiated from photochemical reactions, the thiyl radical derived from TGA abstracts an allylic hydrogen in the B ring of sterols, forming a radical intermediate which rapidly recombines with a second thiyl radical to produce the final tagged product...
November 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29151775/the-application-of-antimicrobial-photodynamic-therapy-apdt-in-dentistry-a-critical-review
#11
E T Carrera, H B Dias, S C T Corbi, R A C Marcantonio, A C A Bernardi, V S Bagnato, M R Hamblin, A N S Rastelli
In recent years there have been an increasing number of in vitro and in vivo studies that show positive results regarding antimicrobial photodynamic therapy (aPDT) used in dentistry. These include applications in periodontics, endodontics, and mucosal infections caused by bacteria present as biofilms. Antimicrobial photodynamic therapy is a therapy based on the combination of a non-toxic photosensitizer (PS) and appropriate wavelength visible light, which in the presence of oxygen is activated to produce reactive oxygen species (ROS)...
December 2016: Laser Physics
https://www.readbyqxmd.com/read/29151609/clues-to-nacn-formation
#12
G Quintana-Lacaci, J Cernicharo, L Velilla Prieto, M Agúndez, A Castro-Carrizo, J P Fonfría, S Massalkhi, J R Pardo
Context: ALMA is providing us essential information on where certain molecules form. Observing where these molecules emission arises from, the physical conditions of the gas, and how this relates with the presence of other species allows us to understand the formation of many species, and to significantly improve our knowledge of the chemistry that occurs in the space. Aims: We studied the molecular distribution of NaCN around IRC +10216, a molecule detected previously, but whose origin is not clear...
November 2017: Astronomy and Astrophysics
https://www.readbyqxmd.com/read/29150682/enantioselective-transformation-of-fluoxetine-in-water-and-its-ecotoxicological-relevance
#13
María Jesús Andrés-Costa, Kathryn Proctor, Marco T Sabatini, Anthony P Gee, Simon E Lewis, Yolanda Pico, Barbara Kasprzyk-Hordern
European legislation focusing on water quality is expected to broaden to encompass several pharmaceuticals as priority hazardous substances. This manuscript aims to challenge current regulatory approaches that do not recognize stereochemistry of chiral pharmaceuticals by testing the hypothesis that environmental transformation and effects of chiral pharmaceuticals are stereoselective. Our experiments revealed that, while degradation of chiral fluoxetine (FL) in river water occurs via non-enantioselective photochemical and mildly-enantioselective microbial processes favoring the (R)-enantiomer, a pronounced enantioselectivity favoring (S)-FL (leading to the formation of (S)-NFL (norfluoxetine)) is observed during activated sludge treatment...
November 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29149535/a-valence-delocalised-osmium-dimer-capable-of-dinitrogen-photocleavage-ab-initio-insights-into-its-electronic-structure
#14
Vera Krewald, Leticia Gonzalez
The search for molecular catalysts that efficiently activate or cleave the dinitrogen molecule is ongoing. While many thermal dinitrogen cleavage catalysts are known, the photochemical activation of N₂ has received considerably less attention. In this paper, we present the first computational study of the osmium dimer [Os(II,III)₂(µ-N₂)(NH₃)₁₀]5+, which was shown to be capable of dinitrogen photocleavage. Despite its deceptively simple geometry, it has a complex electronic structure with a valence-delocalized and electronically degenerate ground state...
November 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29148724/photooxidation-of-aniline-derivatives-can-be-activated-by-freezing-their-aqueous-solutions
#15
Pablo Corrochano, Dana Nachtigallová, Petr Klán
A combined experimental and computational approach was used to investigate the spectroscopic properties of three different aniline derivatives (aniline, N,N-dimethylaniline, and N,N-diethylaniline) in aqueous solutions and at the air-ice interface in the temperature range of 243-298 K. The absorption and diffuse reflectance spectra of ice samples prepared by different techniques, such as slow or shock freezing of the aqueous solutions or vapor deposition on ice grains, exhibited unequivocal bathochromic shifts of 10-15 nm of the absorption maxima of anilines in frozen samples compared to those in liquid aqueous solutions...
November 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29147775/dft-tddft-computational-study-of-the-structural-electronic-and-optical-properties-of-rhodium-iii-and-iridium-iii-complexes-based-on-tris-picolinate-bidentate-ligands
#16
Houari Brahim, Boumediene Haddad, Sefia Brahim, Abdelkrim Guendouzi
The electronic structures and spectroscopic properties of two complexes [M(pic)3] (M = Ir, Rh) containing picolinate as bidentate ligands have been calculated by means density functional theory (DFT) and time-dependent DFT/TD-DFT using three hybrid functionals B3LYP, PBE0 and mPW1PW91. The PBE0 and mPW1PW91 functionals, which have the same HF exchange fraction (25%), give similar results and do not differ drastically from B3LYP results. Calculated geometric parameters of the complexes are in good agreement with the available experimental data...
November 17, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/29146776/light-signaling-dependent-regulation-of-photoinhibition-and-photoprotection-in-tomato
#17
Feng Wang, Nan Wu, Luyue Zhang, Golam Jalal Ahammed, Xiaoxiao Chen, Xun Xiang, Jie Zhou, Xiaojian Xia, Kai Shi, Jingquan Yu, Christine H Foyer, Yanhong Zhou
Photoreceptor-mediated light signaling plays a critical role in plant growth, development, and stress responses but its contribution to the spatial regulation of photoinhibition and photoprotection within the canopy remains unclear. Here, we show that low red/far-red (L-R/FR) ratio light conditions significantly alleviate PSII and PSI photoinhibition in the shade leaves of tomato plants. This protection is accompanied by a phytochrome A (phyA)-dependent induction of LONG HYPOCOTYL 5 (HY5). HY5 binds to the promoter of ABA INSENSITIVE 5 (ABI5), triggering RESPIRATORY BURST OXIDASE HOMOLOG1 (RBOH1)-dependent H2O2 production in the apoplast...
November 16, 2017: Plant Physiology
https://www.readbyqxmd.com/read/29145593/root-respiratory-burst-oxidase-homologue-dependent-h2o2-production-confers-salt-tolerance-on-a-grafted-cucumber-by-controlling-na-exclusion-and-stomatal-closure
#18
Mengliang Niu, Yuan Huang, Shitao Sun, Jingyu Sun, Haishun Cao, Sergey Shabala, Zhilong Bie
Plant salt tolerance can be improved by grafting onto salt-tolerant rootstocks. However, the underlying signaling mechanisms behind this phenomenon remain largely unknown. To address this issue, we used a range of physiological and molecular techniques to study responses of self-grafted and pumpkin-grafted cucumber plants exposed to 75 mM NaCl stress. Pumpkin grafting significantly increased the salt tolerance of cucumber plants, as revealed by higher plant dry weight, chlorophyll content and photochemical efficiency (Fv/Fm), and lower leaf Na+ content...
November 14, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/29145135/forced-and-long-term-degradation-assays-of-tenoxicam-piroxicam-and-meloxicam-in-river-water-degradation-products-and-adsorption-to-sediment
#19
Juan J Jiménez, Beatriz E Muñoz, María I Sánchez, Rafael Pardo
The fate of the pharmaceutical drugs tenoxicam, piroxicam and meloxicam in river water is evaluated here for first time. So, biological, photochemical and thermal degradation assays have been conducted to estimate their degradation rates and know their degradation products. Results indicated that the direct sunlight irradiation, without any protection, promoted a fast degradation of the oxicams while the chemical reactions in solution were less important. The biological degradation in water was negligible except for tenoxicam in whose case its influence was scarce...
October 25, 2017: Chemosphere
https://www.readbyqxmd.com/read/29145130/photophysical-and-photochemical-insights-into-the-photodegradation-of-sulfapyridine-in-water-a-joint-experimental-and-theoretical-study
#20
Heming Zhang, Xiaoxuan Wei, Xuedan Song, Shaheen Shah, Jingwen Chen, Jianhui Liu, Ce Hao, Zhongfang Chen
For organic pollutants, photodegradation, as a major abiotic elimination process and of great importance to the environmental fate and risk, involves rather complicated physical and chemical processes of excited molecules. Herein, we systematically studied the photophysical and photochemical processes of a widely used antibiotic, namely sulfapyridine. By means of density functional theory (DFT) computations, we examined the rate constants and the competition of both photophysical and photochemical processes, elucidated the photochemical reaction mechanism, calculated reaction quantum yield (Φ) based on both photophysical and photochemical processes, and subsequently estimated the photodegradation rate constant...
October 7, 2017: Chemosphere
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