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Wei Liu, Jichun Jiang, Keyong Hou, Weiguo Wang, Yachen Qi, Yan Wang, Yuanyuan Xie, Lei Hua, Haiyang Li
Chlorinated benzenes are typical precursors and indicators for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) emissions from waste incinerators. Online and real-time monitoring of chlorobenzenes is a challenge due to their low concentration and complex nature of the flue gas. In this work, a continuous online monitoring system was built for detection of trace chlorinated benzenes based on a time-of-flight mass spectrometer (TOFMS). A single photon ionization (SPI) source based on a radiofrequency-excited windowless vacuum ultraviolet (VUV) lamp was developed for the first time to eliminate the signal attenuation resulting from the contamination of magnesium fluoride windows and to avoid the fragment ions...
December 1, 2016: Talanta
Ahmet Kemal Aloglu, Peter de B Harrington, Saliha Sahin, Cevdet Demir
Four different data representations were evaluated for the determination of the total antioxidant activities of four different Prunella L. species, which are Prunella vulgaris, Prunella grandiflora, Prunella laciniata, and Prunella orientalis Bornm. Three different antioxidant assays, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABST), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and Folin-Ciocalteu (FC) reagent measured the total antioxidant activity and phenolic content of the four Prunella L. species that were extracted with 12 different solvent systems...
December 1, 2016: Talanta
Ang Li, Xiang Li, Xujiang Yu, Wei Li, Ruyi Zhao, Xiao An, Daxiang Cui, Xiaoyuan Chen, Wanwan Li
In this work, we report a successful synthesis of copper bismuth sulfide nanorods (NRs) with broad and strong photoabsorption ranging from ultraviolet (UV) to near-infrared (NIR) wavelengths, which can be used as a 1064 nm-laser-driven photothermal agent with the photothermal conversion efficiency of 40.7%, noticeably higher than most of the reported PTT agents working in NIR-II window. The as-prepared PEGylated Cu3BiS3 NRs were used as photoacoustic imaging (PAI) and CT imaging agents due to their strong NIR absorption and large X-ray attenuation coefficient of bismuth...
October 12, 2016: Biomaterials
Tiejun Chen, Hu Hou, Yan Fan, Shikai Wang, Qianru Chen, Leilei Si, Bafang Li
Chronic exposure to ultraviolet (UV) irradiation causes skin photoaging. This study was undertaken to identify the anti-photoaging mechanisms of gelatin hydrolysate (CH) derived from pacific cod skin. Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) and ELISA assays were used to investigate the effects of CH on matrix metalloproteinases (MMPs) and the signaling pathways after UV irradiation by using a mice skin photoaging model. The average molecular weight of CH was 1200Da, and 273/1000 residues were hydrophobic, Gly-Pro and Gly-Leu sequences and Arg at C-terminus appeared frequently in CH...
October 14, 2016: Journal of Photochemistry and Photobiology. B, Biology
Jesús Ignacio Mendieta-Moreno, Daniel G Trabada, Jesus Mendieta, James P Lewis, Paulino Gómez-Puertas, Jose Ortega
The absorption of ultraviolet radiation by DNA may result in harmful genetic lesions that affect DNA replication and transcription, ultimately causing mutations, cancer and/or cell death. We analyze the most abundant photochemical reaction in DNA, the cyclobutane thymine dimer, using hybrid quantum mechanics / molecular mechanics (QM/MM) techniques and QM/MM nonadiabatic molecular dynamics. We find that, due to its double helix structure, DNA presents a free energy barrier between non-reactive and reactive conformations leading to the photolesion...
October 21, 2016: Journal of Physical Chemistry Letters
Radwan Elzein, Chun-Min Chang, Inna Ponomareva, Wen-Yang Gao, Shengqian Ma, Rudy Schlaf
Metal-organic frameworks (MOFs) deposited from solution have the potential to form 2-dimensional supramolecular thin films suitable for molecular electronic applications. However, the main challenges lie in achieving selective attachment to the substrate surface, and the integration of organic conductive ligands into the MOF structure to achieve conductivity. The presented results demonstrate that photoemission spectroscopy combined with preparation in a system-attached glovebox can be used to characterize the electronic structure of such systems...
October 21, 2016: ACS Applied Materials & Interfaces
Alexandra R McNeill, Adam R Hyndman, Roger J Reeves, Alison J Downard, Martin Ward Allen
ZnO is a prime candidate for future use in transparent electronics however development of practical materials requires attention to factors including control of its unusual surface band bending and surface reactivity. In this work, we have modified the O polar (000(1)over bar), Zn-polar (0001), and m-plane (10(1)over bar0) surfaces of ZnO with phosphonic acid (PA) derivatives and measured the effect on the surface band bending and surface sensitivity to atmospheric oxygen. Core level and valence band synchrotron X-ray photoemission spectroscopy were used to measure the surface band bending introduced by PA modifiers with substituents of opposite polarity dipole moment: octadecylphosphonic acid (ODPA) and 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctylphosphonic acid (F13OPA)...
October 21, 2016: ACS Applied Materials & Interfaces
Michelle R Robinson, Jennifer S Brodbelt
Tyrosine sulfation is an important post-translational modification but remains difficult to detect in biological samples owing to its low stoichiometric abundance and the lack of effective enrichment methods. In the present study, weak anion exchange (WAX) is evaluated for the enrichment of sulfopeptides that have been modified via carbamylation to convert all primary amines to less basic carbamates. The decrease in basicity enhanced the binding of carbamylated sulfopeptides to WAX resin relative to non-sulfated peptides...
October 21, 2016: Analytical Chemistry
Lisa A Sawicki, April M Kloxin
Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In particular, light-mediated click reactions, such as photoinitiated thiol-ene and thiol-yne reactions, afford spatiotemporal control over material properties and allow the design of systems with a high degree of user-directed property control. Fabrication and modification of hydrogel-based biomaterials using the precision afforded by light and the versatility offered by these thiol-X photoclick chemistries are of growing interest, particularly for the culture of cells within well-defined, biomimetic microenvironments...
September 29, 2016: Journal of Visualized Experiments: JoVE
Vi Khanh Truong, Miljan Stefanovic, Shane Maclaughlin, Mark Tobin, Jitraporn Vongsvivut, Mohammad Al Kobaisi, Russell J Crawford, Elena P Ivanova
Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, building and food industries, amongst others. Polyester and coatings containing both polyester and silica nanoparticles (SiO2NPs) have been widely used to protect steel substrata from corrosion. In this study, we utilized X-ray photoelectron spectroscopy, attenuated total reflection infrared micro-spectroscopy, water contact angle measurements, optical profiling and atomic force microscopy to provide an insight into how exposure to sunlight can cause changes in the micro- and nanoscale integrity of the coatings...
October 11, 2016: Journal of Visualized Experiments: JoVE
Masaru Nakagawa, Akifumi Nakaya, Yasuto Hoshikawa, Shunya Ito, Nobuya Hiroshiba, Takashi Kyotani
Ultraviolet (UV) nanoimprint lithography is a promising nanofabrication technology with cost efficiency and high throughput for sub-20 nm size semiconductor, data storage, and optical devices. To test formability of organic resist mask patterns, we investigated whether the type of polymerizable di(meth)acrylate monomer affected the fabrication of cured resin nanopillars by UV nanoimprinting using molds with pores of around 20 nm. We used carbon-coated, porous, anodic aluminum oxide (AAO) films prepared by electrochemical oxidation and thermal chemical vapor deposition as molds, because the pore diameter distribution in the range of 10-40 nm was suitable for combinatorial testing to investigate whether UV-curable resins comprising each monomer were filled into the mold recesses in UV nanoimprinting...
October 21, 2016: ACS Applied Materials & Interfaces
Hamid Reza Samadikhah, Maryam Nikkhah, Saman Hosseinkhani
Two quantum dots (QDs), a green emitter, CdSe and a red emitter, CdSe with ZnS shell are encapsulated into novel liposomes in two different formulations including cationic liposomes. Quantum dots have proven themselves as powerful inorganic fluorescent probes, especially for long-term, multiplexed imaging and detection. Upon delivery into a cell, in endocytic vesicles such as endosomes, their fluorescence is quenched. We have investigated the potential toxic effects, photophysical properties and cell internalization of QDs in new formulation of liposomes as an in vitro vesicle model...
October 21, 2016: Luminescence: the Journal of Biological and Chemical Luminescence
Yu Harabuchi, Rina Yamamoto, Satoshi Maeda, Satoshi Takeuchi, Tahei Tahara, Tetsuya Taketsugu
Ab initio molecular dynamics (AIMD) simulations were carried out for *-excited 1,1'-dimethylstilbene (dmSB) at the spin-flip time-dependent density functional theory (SF-TDDFT) level with the TSF-index technique, to get insights into the substitution effects on the photoisomerization dynamics of stilbene (SB). It is found that the reaction path from the Franck-Condon structure of cis-dmSB is oriented toward the 4,4-dihydrophenanthrene (DHP) side from the beginning, which is in contrast to the case of SB where the pathway is oriented toward the twist-side in the initial stage...
October 21, 2016: Journal of Physical Chemistry. A
Alessandra Souza Barbosa, Filipe Ferreira da Silva, Andre Rebelo, Søren Vrønning Hoffmann, Marcio H F Bettega, Paulo Limao-Vieira
Here we report novel comprehensive investigations on the electronic state spectroscopies of isolated 2,4- and 2,6-difluorotoluene in the gas phase by high-resolution vacuum ultraviolet (VUV) photoabsorption measurements in the 4.4-10.8 eV energy-range, with absolute cross-section values derived. We also present the first set of ab initio calculations (vertical energies and oscillator strengths), which we have used in the assignment of valence transitions of the difluorotoluene molecules, together with calculated ionisation energies to obtain the Rydberg transitions for both molecules...
October 21, 2016: Journal of Physical Chemistry. A
Alfio Torrisi, Przemyslaw Wachulak, Łukasz Węgrzyński, Tomasz Fok, Andrzej Bartnik, Tomáš Parkman, Šárka Vondrová, Jana Turňová, Bartłomiej J Jankiewicz, Bartosz Bartosewicz, Henryk Fiedorowicz
We report on a very compact desk-top transmission extreme ultraviolet (EUV) microscope based on a laser-plasma source with a double stream gas-puff target, capable of acquiring magnified images of objects with a spatial (half-pitch) resolution of sub-50 nm. A multilayer ellipsoidal condenser is used to focus and spectrally narrow the radiation from the plasma, producing a quasi-monochromatic EUV radiation (λ = 13.8 nm) illuminating the object, whereas a Fresnel zone plate objective forms the image. Design details, development, characterization and optimization of the EUV source and the microscope are described and discussed...
October 21, 2016: Journal of Microscopy
Aleksey B Smirnov, Serhii B Kryvyi, Sergii A Mulenko, Maria L Sadovnikova, Rada K Savkina, Nicolaie Stefan
Ultraviolet photons of KrF laser (248 nm) was used for the synthesis of nanometric films based on iron and chromium oxides (Fe2O3 - X (0 ≤ x ≤ 1) and Cr3 - X O3 - Y (0 ≤ x ≤ 2; 0 ≤ y ≤ 2)) with variable thickness, stoichiometry, and electrical properties. Film deposition was carried out on the silicon substrate Si < 100 > at the substrate's temperature T S = 293 K. X-ray diffraction and X-ray reflectometry analysis were used for the obtained structure characterization...
December 2016: Nanoscale Research Letters
Li Shing Teoh, Ola Lasekan, Noranizan Mohd Adzahan, Norhashila Hashim
In this work, potato slices were exposed to different doses of UV-C irradiation (i.e. 2.28, 6.84, 11.41, and 13.68 kJ m(-2)) with or without pretreatment [i.e. ascorbic acid and calcium chloride (AACCl) dip] and stored at 4 ± 1 °C. Changes in enzymatic activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL), as well as total phenolic content (TPC) were investigated after 0, 3, 7 and 10 days of storage. Results showed that untreated and UV-C treated potato slices at 13...
July 2016: Journal of Food Science and Technology
Bingxian Yang, Qijie Guan, Jingkui Tian, Setsuko Komatsu
: High level of UV-B irradiation followed by dark treatment (HUV-B+D) causes accumulation of secondary metabolites in Clematis terniflora DC. To investigate the response mechanism under HUV-B+D, transcriptomic and proteomic analyses were performed in leaves of C. terniflora. The number of genes related to tetrapyrrole synthesis, amino acid metabolism, tricarboxylic acid cycle, and mitochondrial electron transport chains was hierarchically changed in leaves of C. terniflora under HUV-B+D...
October 17, 2016: Journal of Proteomics
Xuanyi Meng, Yuxin Bai, Jinyan Gao, Xin Li, Hongbing Chen
Bovine β-lactoglobulin (β-Lg) is recognized as a significant milk allergen in several countries. In this study, β-Lg was isolated and treated with high hydrostatic pressure (HHP) at 100, 200, 300, 400, and 500MPa. The allergenic properties of the HHP-treated β-Lg were characterized by indirect competitive enzyme-linked immunosorbent assay with anti-β-Lg rabbit antibody and the sera of patients allergic to cows' milk. The conformation of the HHP-treated β-Lg was examined with ultraviolet absorption spectroscopy, endogenous fluorescence spectroscopy, exogenous fluorescence spectroscopy, and circular dichroism spectroscopy analyses...
March 15, 2017: Food Chemistry
Masahiro Ohgami, Masato Homma, Yoshiharu Suzuki, Kanako Naito, Motoko Yamada, Shoichi Mitsuhashi, Fumie Fujisawa, Hiroshi Kojima, Takayuki Kaburagi, Keiko Uchiumi, Yutaka Yamada, Hiroko Bando, Hisato Hara, Keiji Takei
BACKGROUND: Lapatinib and erlotinib are used for cancer treatment, showing large interindividual variability. Therapeutic drug monitoring may be useful for assessing the clinical outcomes and adverse events. A simple high-performance liquid chromatography ultraviolet method was developed for the determination of lapatinib and erlotinib in human plasma. METHODS: An aliquot of plasma sample spiked with IS was treated with acetonitrile to precipitate the proteins. Lapatinib and erlotinib were separated on an octadecylsilyl silica-gel column using a mobile phase consisting of acetonitrile, methanol, water, and trifluoroacetic acid (26:26:48:0...
October 17, 2016: Therapeutic Drug Monitoring
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