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https://www.readbyqxmd.com/read/28335365/antibacterial-properties-of-visible-light-responsive-carbon-containing-titanium-dioxide-photocatalytic-nanoparticles-against-anthrax
#1
Der-Shan Sun, Jyh-Hwa Kau, Hsin-Hsien Huang, Yao-Hsuan Tseng, Wen-Shiang Wu, Hsin-Hou Chang
The bactericidal activity of conventional titanium dioxide (TiO₂) photocatalyst is effective only on irradiation by ultraviolet light, which restricts the applications of TiO₂ for use in living environments. Recently, carbon-containing TiO₂ nanoparticles [TiO₂(C) NP] were found to be a visible-light-responsive photocatalyst (VLRP), which displayed significantly enhanced antibacterial properties under visible light illumination. However, whether TiO₂(C) NPs exert antibacterial properties against Bacillus anthracis remains elusive...
December 9, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335355/influence-of-external-gaseous-environments-on-the-electrical-properties-of-zno-nanostructures-obtained-by-a-hydrothermal-method
#2
Marcin Procek, Tadeusz Pustelny, Agnieszka Stolarczyk
This paper deals with experimental investigations of ZnO nanostructures, consisting of a mixture of nanoparticles and nanowires, obtained by the chemical (hydrothermal) method. The influences of both oxidizing (NO₂) and reducing gases (H₂, NH₃), as well as relative humidity (RH) on the physical and chemical properties of ZnO nanostructures were tested. Carrier gas effect on the structure interaction with gases was also tested; experiments were conducted in air and nitrogen (N₂) atmospheres. The effect of investigated gases on the resistance of the ZnO nanostructures was tested over a wide range of concentrations at room temperature (RT) and at 200 °C...
November 29, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335328/investigation-of-the-mechanical-properties-and-microstructure-of-graphene-nanoplatelet-cement-composite
#3
Baomin Wang, Ruishuang Jiang, Zhenlin Wu
In this work, graphene nanoplatelets (GNPs) were dispersed uniformly in aqueous solution using methylcellulose (MC) as a dispersing agent via ultrasonic processing. Homogenous GNP suspensions were incorporated into the cement matrix to investigate the effect of GNPs on the mechanical behavior of cement paste. The optimum concentration ratio of GNPs to MC was confirmed as 1:7 by ultraviolet visible spectroscopy (UV-Vis), and the optical microscope and transmission electron microscopy (TEM) images displayed remarkable dispersing performance...
November 4, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335303/detection-of-prohibited-fish-drugs-using-silver-nanowires-as-substrate-for-surface-enhanced-raman-scattering
#4
Jia Song, Yiqun Huang, Yuxia Fan, Zhihui Zhao, Wansong Yu, Barbara A Rasco, Keqiang Lai
Surface-enhanced Raman scattering or surface-enhanced Raman spectroscopy (SERS) is a promising detection technology, and has captured increasing attention. Silver nanowires were synthesized using a rapid polyol method and optimized through adjustment of the molar ratio of poly(vinyl pyrrolidone) and silver nitrate in a glycerol system. Ultraviolet-visible spectrometry, X-ray diffraction, and transmission electron microscopy were used to characterize the silver nanowires. The optimal silver nanowires were used as a SERS substrate to detect prohibited fish drugs, including malachite green, crystal violet, furazolidone, and chloramphenicol...
September 21, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335296/controlled-mechanical-cracking-of-metal-films-deposited-on-polydimethylsiloxane-pdms
#5
Andreas Polywka, Luca Stegers, Oliver Krauledat, Thomas Riedl, Timo Jakob, Patrick Görrn
Stretchable large area electronics conform to arbitrarily-shaped 3D surfaces and enables comfortable contact to the human skin and other biological tissue. There are approaches allowing for large area thin films to be stretched by tens of percent without cracking. The approach presented here does not prevent cracking, rather it aims to precisely control the crack positions and their orientation. For this purpose, the polydimethylsiloxane (PDMS) is hardened by exposure to ultraviolet radiation (172 nm) through an exposure mask...
September 9, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335258/nanostructures-derived-from-starch-and-chitosan-for-fluorescence-bio-imaging
#6
Yinxue Zu, Jingran Bi, Huiping Yan, Haitao Wang, Yukun Song, Bei-Wei Zhu, Mingqian Tan
Fluorescent nanostructures (NSs) derived from polysaccharides have drawn great attention as novel fluorescent probes for potential bio-imaging applications. Herein, we reported a facile alkali-assisted hydrothermal method to fabricate polysaccharide NSs using starch and chitosan as raw materials. Transmission electron microscopy (TEM) demonstrated that the average particle sizes are 14 nm and 75 nm for starch and chitosan NSs, respectively. Fourier transform infrared (FT-IR) spectroscopy analysis showed that there are a large number of hydroxyl or amino groups on the surface of these polysaccharide-based NSs...
July 5, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335255/a-gallium-oxide-graphene-oxide-hybrid-composite-for-enhanced-photocatalytic-reaction
#7
Seungdu Kim, Kook In Han, In Gyu Lee, Won Kyu Park, Yeojoon Yoon, Chan Sei Yoo, Woo Seok Yang, Wan Sik Hwang
Hybrid composites (HCs) made up of gallium oxide (GaO) and graphene oxide (GO) were investigated with the intent of enhancing a photocatalytic reaction under ultraviolet (UV) radiation. The material properties of both GaO and GO were preserved, even after the formation of the HCs. The incorporation of the GO into the GaO significantly enhanced the photocatalytic reaction, as indicated by the amount of methylene blue (MB) degradation. The improvements in the reaction were discussed in terms of increased surface area and the retarded recombination of generated charged carriers...
July 1, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335246/quaternized-carboxymethyl-chitosan-based-silver-nanoparticles-hybrid-microwave-assisted-synthesis-characterization-and-antibacterial-activity
#8
Siqi Huang, Jing Wang, Yang Zhang, Zhiming Yu, Chusheng Qi
A facile, efficient, and eco-friendly approach for the preparation of uniform silver nanoparticles (Ag NPs) was developed. The synthesis was conducted in an aqueous medium exposed to microwave irradiation for 8 min, using laboratory-prepared, water-soluble quaternized carboxymethyl chitosan (QCMC) as a chemical reducer and stabilizer and silver nitrate as the silver source. The structure of the prepared QCMC was characterized using Fourier transform infrared (FT-IR) and ¹H nuclear magnetic resonance (NMR)...
June 17, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335242/targeting-and-photodynamic-killing-of-cancer-cell-by-nitrogen-doped-titanium-dioxide-coupled-with-folic-acid
#9
Jin Xie, Xiaobo Pan, Mengyan Wang, Longfang Yao, Xinyue Liang, Jiong Ma, Yiyan Fei, Pei-Nan Wang, Lan Mi
Titanium dioxide (TiO₂) has attracted wide attention as a potential photosensitizer (PS) in photodynamic therapy (PDT). However, bare TiO₂ can only be excited by ultraviolet illumination, and it lacks specific targeting ligands, which largely impede its application. In our study, we produced nitrogen-doped TiO₂ and linked it with an effective cancer cell targeting agent, folic acid (FA), to obtain N-TiO₂-FA nanoconjugates. Characterization of N-TiO₂-FA included Zeta potential, absorption spectra and thermogravimetric analysis...
June 14, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335227/synthesis-of-ball-like-ag-nanorod-aggregates-for-surface-enhanced-raman-scattering-and-catalytic-reduction
#10
Wenjing Zhang, Yin Cai, Rui Qian, Bo Zhao, Peizhi Zhu
In this work, ball-like Ag nanorod aggregates have been synthesized via a simple seed-mediated method. These Ag mesostructures were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), and X-ray diffraction (XRD). Adding a certain amount of polyvinyl pyrrolidone (PVP) can prolong its coagulation time. These Ag nanorod aggregates exhibit effective SERS effect, evaluated by Rhodamine 6G (R6G) and doxorubicin (DOX) as probe molecules...
May 25, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335223/ultraviolet-plasmonic-aluminium-nanoparticles-for-highly-efficient-light-incoupling-on-silicon-solar-cells
#11
Yinan Zhang, Boyuan Cai, Baohua Jia
Plasmonic metal nanoparticles supporting localized surface plasmon resonances have attracted a great deal of interest in boosting the light absorption in solar cells. Among the various plasmonic materials, the aluminium nanoparticles recently have become a rising star due to their unique ultraviolet plasmonic resonances, low cost, earth-abundance and high compatibility with the complementary metal-oxide semiconductor (CMOS) manufacturing process. Here, we report some key factors that determine the light incoupling of aluminium nanoparticles located on the front side of silicon solar cells...
May 24, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28334920/spe-hplc-determination-of-chlorogenic-and-phenolic-acids-in-coffee
#12
Pelin Köseoglu Yilmaz, Ufuk Kolak
A new solid phase extraction-high-performance liquid chromatography method with ultraviolet detection was developed and validated for the determination of three chlorogenic acids (5-O-caffeoylquinic, 3-O-caffeoylquinic and 4-O-caffeoylquinic acids) and six phenolic acids (caffeic, ferulic, sinapic, protocatechuic, p-hydroxybenzoic acid (PHBA) and vanillic acid (VA)) in coffee bean samples. Extraction was performed using hydrophilic-lipophilic balance cartridges. Separations were accomplished using a C18 guard column (10 × 2...
March 18, 2017: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/28334796/determination-of-meloxicam-in-egg-whites-and-yolks-using-reverse-phase-chromatography
#13
Sherry Cox, Joan Bailey, Molly White, Kristen Gordon, Marcy Souza
A new method of analysis has been developed and validated for the determination of meloxicam in egg whites and yolks. Following a liquid extraction for the whites and a solid phase extraction for the yolks, samples were separated on an XBridge C18 column and quantified using ultraviolet detection at 360 nm. The mobile phase was a mixture of water with glacial acetic acid and acetonitrile, with a flow rate of 1 mL/min. The procedure produced a linear graph over the concentration range 5-1500 ng/mL with a lower limit of quantification of 5 ng/mL...
March 2, 2017: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/28334768/repair-of-uv-induced-dna-lesions-in-natural-saccharomyces-cerevisiae-telomeres-is-moderated-by-sir2-and-sir3-and-inhibited-by-yku-sir4-interaction
#14
Laetitia Guintini, Maxime Tremblay, Martin Toussaint, Annie D'Amours, Ralf E Wellinger, Raymund J Wellinger, Antonio Conconi
Ultraviolet light (UV) causes DNA damage that is removed by nucleotide excision repair (NER). UV-induced DNA lesions must be recognized and repaired in nucleosomal DNA, higher order structures of chromatin and within different nuclear sub-compartments. Telomeric DNA is made of short tandem repeats located at the ends of chromosomes and their maintenance is critical to prevent genome instability. In Saccharomyces cerevisiae the chromatin structure of natural telomeres is distinctive and contingent to telomeric DNA sequences...
February 21, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28332621/evolution-analysis-of-euv-radiation-from-laser-produced-tin-plasmas-based-on-a-radiation-hydrodynamics-model
#15
M G Su, Q Min, S Q Cao, D X Sun, P Hayden, G O'Sullivan, C Z Dong
One of fundamental aims of extreme ultraviolet (EUV) lithography is to maximize brightness or conversion efficiency of laser energy to radiation at specific wavelengths from laser produced plasmas (LPPs) of specific elements for matching to available multilayer optical systems. Tin LPPs have been chosen for operation at a wavelength of 13.5 nm. For an investigation of EUV radiation of laser-produced tin plasmas, it is crucial to study the related atomic processes and their evolution so as to reliably predict the optimum plasma and experimental conditions...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28332207/the-eyes-and-vision-of-butterflies
#16
Kentaro Arikawa
Butterflies use colour vision when searching for flowers. Unlike the trichromatic retinas of humans (blue, green, and red cones; plus rods) and honeybees (ultraviolet, blue, and green photoreceptors), butterfly retinas typically have six or more photoreceptor classes with distinct spectral sensitivities. The eyes of the Japanese yellow swallowtail (Papilio xuthus) contain ultraviolet, violet, blue, green, red and broad-band receptors, with each ommatidium housing nine photoreceptor cells in one of three fixed combinations...
March 22, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28330776/topical-application-of-glycolic-acid-suppresses-the-uvb-induced-il-6-il-8-mcp-1-and-cox-2-inflammation-by-modulating-nf-%C3%AE%C2%BAb-signaling-pathway-in-keratinocytes-and-mice-skin
#17
Sheau-Chung Tang, Pei-Yun Liao, Sung-Jen Hung, Jheng-Siang Ge, Shiou-Mei Chen, Ji-Ching Lai, Yu-Ping Hsiao, Jen-Hung Yang
BACKGROUND: Glycolic acid (GA), commonly present in fruits, has been used to treat dermatological diseases. Extensive exposure to solar ultraviolet B (UVB) irradiation plays a crucial role in the induction of skin inflammation. The development of photo prevention from natural materials represents an effective strategy for skin keratinocytes. OBJECTIVE: The aim of this study was to investigate the molecular mechanisms underlying the glycolic acid (GA)-induced reduction of UVB-mediated inflammatory responses...
March 11, 2017: Journal of Dermatological Science
https://www.readbyqxmd.com/read/28330720/attenuation-of-uvr-induced-vitamin-d3-synthesis-in-a-mouse-model-deleted-for-keratinocyte-lathosterol-5-desaturase
#18
Anastasia M Makarova, Saloni Pasta, Gordon Watson, Cedric Shackleton, Ervin H Epstein
The lower risk of some internal cancers at lower latitudes has been linked to greater sun exposure and consequent higher levels of ultraviolet radiation (UVR)-produced vitamin D3 (D3). To separate the experimental effects of sunlight and of all forms of D3, a mouse in which UVR does not produce D3 would be useful. To this end we have generated mice carrying a modified allele of sterol C5-desaturase (Sc5d), the gene encoding the enzyme that converts lathosterol to 7-dehydrocholesterol (7-DHC), such that Sc5d expression can be inactivated using the Cre/lox site-specific recombination system...
March 19, 2017: Journal of Steroid Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/28330282/in-vitro-cytotoxicity-and-antibacterial-activity-of-silver-coated-electrospun-polycaprolactone-gelatine-nanofibrous-scaffolds
#19
Mim Mim Lim, Naznin Sultana
The development of nano-sized scaffolds with antibacterial properties that mimic the architecture of tissue is one of the challenges in tissue engineering. In this study, polycaprolactone (PCL) and PCL/gelatine (Ge) (70:30) nanofibrous scaffolds were fabricated using a less toxic and common solvent, formic acid and an electrospinning technique. Nanofibrous scaffolds were coated with silver (Ag) in different concentrations of silver nitrate (AgNO3) aqueous solution (1.25, 2.5, 5, and 10 %) by using dipping method, drying and followed by ultraviolet (UV) photoreduction...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28330190/phyto-synthesis-and-structural-characterization-of-catalytically-active-gold-nanoparticles-biosynthesized-using-delonix-regia-leaf-extract
#20
Preeti Dauthal, Mausumi Mukhopadhyay
Biological methods of nanoparticles synthesis are ecologically sound and sustainable alternative to the conventional methods. On the basis of aforesaid premise, the present study deals with the optimization and fabrication of gold nanoparticles (Au-NPs) using easily available bio-resource, Delonix regia leaf extract. The use of practically nontoxic natural extracts and water allows the synthesis pathways presented to be considered as ''green'' and so permitting the synthesized Au-NPs to be used in sensitive areas, such as bioremediation...
December 2016: 3 Biotech
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