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Agnieszka Grzelak, Maria Wojewódzka, Sylwia Meczynska-Wielgosz, Mariusz Zuberek, Dominika Wojciechowska, Marcin Kruszewski
Damage to mitochondria and subsequent ROS leakage is a commonly accepted mechanism of nanoparticle toxicity. However, malfunction of mitochondria results in generation of superoxide anion radical (O2•-), which due to the relatively low chemical reactivity is rather unlikely to cause harmful effects triggered by nanoparticles. We show that treatment of HepG2 cells with silver nanoparticles (AgNPs) resulted in generation of H2O2 instead of O2•-, as measured by ROS specific mitochondrial probes. Moreover, addition of a selective iron chelator diminished AgNPs toxicity...
January 9, 2018: Redox Biology
Majid Nasiriboroumand, Majid Montazer, Hossein Barani
The potential application of any nanoparticles, including silver nanoparticles (AgNPs), strongly depends on their stability against aggregation. In the current study, an aqueous extract of pomegranate peel was used as a stabilizer during synthesis of AgNPs. Nanoparticles have been prepared by the chemical reduction method from an aqueous solution of silver nitrate in the presence of sodium borohydride as a reducing agent. The AgNPs were characterized by dynamic light scattering (DLS), zeta-potential measurements, UV-Vis spectroscopy and transmission electron microscopy (TEM)...
January 10, 2018: Journal of Photochemistry and Photobiology. B, Biology
Shih-Jen Lin, Jyh-Ming Ting, Kuo-Chin Hsu, Yaw-Shyan Fu
A novel composite photocatalyst based on Cu₂ZnSnS₄ (CZTS) powders was synthesized and investigated for use as a photocatalyst. CZTS powders were first made using a conventional hydrothermal method and were then used to grow silver nanoparticles hybridized onto the CZTS under various conditions through a microwave-assisted hydrothermal process. After the obtained samples were subsequently mixed with 1T-2H MoS₂, the three synthesized component samples were characterized using X-ray diffractometry (XRD), scanning electron microscopy, transmission electron microscopy (FE-SEM, FE-TEM), UV-visible spectroscopy (UV-Vis), Brunauer-Emmet-Teller (BET), photoluminescence spectroscopy (PL), and X-ray photoelectron spectroscopy (XPS)...
January 19, 2018: Materials
Marcin Szalkowski, Karolina Sulowska, Justyna Grzelak, Joanna Niedziółka-Jönsson, Ewa Roźniecka, Dorota Kowalska, Sebastian Maćkowski
We apply wide-field fluorescence microscopy to measure real-time attachment of photosynthetic proteins to plasmonically active silver nanowires. The observation of this effect is enabled, on the one hand, by sensitive detection of fluorescence and, on the other hand, by plasmonic enhancement of protein fluorescence. We examined two sample configurations with substrates being a bare glass coverslip and a coverslip functionalized with a monolayer of streptavidin. The different preparation of the substrate changes the observed behavior as far as attachment of the protein is concerned as well as its subsequent photobleaching...
January 19, 2018: Sensors
Robert C Kern, J Pablo Stolovitzky, Stacey L Silvers, Ameet Singh, Jivianne T Lee, David M Yen, Alfred M C Iloreta, Francis P J Langford, Boris Karanfilov, Keith E Matheny, James W Stambaugh, Anna K Gawlicka
BACKGROUND: Topical intranasal corticosteroid sprays (INCSs) are standard treatment for nasal polyps (NPs), but their efficacy is reduced by poor patient compliance and impaired access of drug to the sinus mucosa. A corticosteroid-eluting sinus implant was designed to address these limitations in patients with recurrent polyposis after sinus surgery by delivering 1350 μg of mometasone furoate (MF) directly to the ethmoid sinus mucosa over approximately 90 days. METHODS: A randomized, sham-controlled, double-blind trial was undertaken in 300 adults with refractory chronic rhinosinusitis with NPs (CRSwNP), who were candidates for repeat surgery...
January 19, 2018: International Forum of Allergy & Rhinology
Rouhollah Dermanaki Farahani, Mathieu Janier, Martine Dubé
In the present work, a conductive film of silver nanoparticles (nAg) as a novel heating element type, called susceptor was developed and tested for induction welding of carbon fiber/polyphenylene sulfide (CF/PPS) thermoplastic composites, i.e., unidirectional pre-impregnated16 plies of CF/PPS compression-molded in a quasi-isotropic stacking sequence. The nAg were synthesized, dispersed in deionized (DI) water and casted onto a pure PPS film, resulting in a conductive film upon the evaporation of DI water and thermal post-annealing...
January 19, 2018: Nanotechnology
Yingnan Wang, Xiaoteng Li, Manzhang Xu, Kai Wang, Hongyang Zhu, Wu Zhao, Junfeng Yan, Zhiyong Zhang
Binary Ag2S nanocrystals (NCs) have many potential optical applications because of their low toxicity, narrow direct band gaps and near-infrared photoluminescence (PL) with high emission efficiency. However, due to its small exciton Bohr radius (2.2 nm), the PL spectra of Ag2S NCs can only be modulated below ∼1200 nm with increasing particle size. Meanwhile, ternary silver copper chalcogenides (AgCuX, X = S, Se) have also attracted increased attention in recent years. Temperature-dependent structural phase transformation leads electrical transport to exhibit fascinating transitions between p and n type conduction, which makes AgCuS and AgCuSe ideal materials for diode or transistor devices...
January 19, 2018: Nanoscale
L Qiu, J C Dong, F Ding
Although the study of black phosphorene (BP) and its isomers has attracted enormous attention, the method of synthesizing high-quality samples in a large area is still pending. Here we explore the potential of using the chemical vapor deposition method to synthesize large-area two-dimensional (2D) phosphorene films on metal surfaces. Our ab initio calculations show that BP can be synthesized by using tin (Sn) as a catalyst, while one of its isomers, blue phosphorene (BLP), is very possible to be synthesized by using most other metals, such as Ag and Au...
January 19, 2018: Nanoscale
Samantha M Wisely, Katherine A Sayler, C Jane Anderson, Carisa L Boyce, Amy R Klegarth, Steve A Johnson
We compiled records on macacine herpesvirus 1 (McHV-1) seroprevalence and, during 2015-2016, collected saliva and fecal samples from the free-ranging rhesus macaques of Silver Springs State Park, a popular public park in central Florida, USA, to determine viral DNA shedding and perform sequencing. Phylogenetic analysis of the US5 and US5-US6 intragenic sequence from free-ranging and laboratory McHV-1 variants did not reveal genomic differences. In animals captured during 2000-2012, average annual seroprevalence was 25% ± 9 (mean ± SD)...
February 2018: Emerging Infectious Diseases
Andrei Nikolaev, Claude Y Legault, Minhao Zhang, Arturo Orellana
A well-defined homogeneous silver precatalyst can be utilized for the direct C-H functionalization of a wide range of aromatic nitrogen heterocycles with cyclopropanols under acid-free conditions. This reaction can be conducted on gram-scale and with low catalyst loadings (as low as 1%), which is rare for silver-catalyzed Minisci-type reactions. Moreover, reactivity trends, as well as steric and calculated electronic properties of the heterocycles, strongly suggest that silver-heterocycle complexes formed in situ behave as redox active catalysts and as Lewis acid activators of the heterocycle and that the electronic nature of the heterocyclic substrates tunes the reactivity of the resulting complexes...
January 19, 2018: Organic Letters
Hongcai He, Zhuolin Jiang, Zhaoling He, Tao Liu, Enzhu Li, Bao-Wen Li
An excellent ternary composite photocatalyst consisting of silver orthophosphate (Ag3PO4), attapulgite (ATP), and TiO2 was synthesized, in which heterojunction was formed between dissimilar semiconductors to promote the separation of photo-generated charges. The ATP/TiO2/Ag3PO4 composite was characterized by SEM, XRD, and UV-vis diffuse reflectance spectroscopy. The co-deposition of Ag3PO4 and TiO2 nanoparticles onto the surface of ATP forms a lath-particle structure. Compared with composite photocatalysts consisting of two phases, ATP/TiO2/Ag3PO4 ternary composite exhibits greatly improved photocatalytic activity for degradation of rhodamine B under simulated solar irradiation...
January 18, 2018: Nanoscale Research Letters
Abdul-Hossein Almirtaha, Mohammad Eftekhari, Mahmoud Chamsaz, Mohammad Gheibi
In this paper, menthe pulegium leaves extract was used as a green reducing agent for synthesis of silver-nanoparticles from silver ion solution. The synthesized silver nanoparticles were characterized by ultraviolet-visible spectrophotometry, transmission electron microscopy, X-Ray spectroscopy and used as adsorbent in solid phase extraction for preconcentration of trace levels of cadmium (ІІ). After desorption of cadmium (ІІ) in 5 mol L-1 formic acid, the desorbent solution was aspirated into the flame atomic absorption spectrometry for determination of cadmium...
January 18, 2018: Environmental Technology
Meital Harel, Haim Taitelbaum
The temperature effect on the dynamics and geometry of a mercury droplet (∼150 μm) spreading on a silver substrate (4000 Å) was studied. The system temperature was controlled by a heating stage in the temperature range of -15 °C < T < 25 °C, and the spreading process was monitored using an optical microscope. We studied the wetting dynamics (droplet radius and velocity) as a function of temperature. We found that for all studied temperatures, the spreading radius R(t) grows linearly with time, with a velocity value depending on temperature...
December 2017: Physical Review. E
Julio C Hernández, J Adrián Reyes
We analyzed the optical band gaps for axially propagating electromagnetic waves throughout a metallic doped cholesteric elastomer. The composed medium is made of metallic nanospheres (silver) randomly dispersed in a cholesteric elastomer liquid crystal whose dielectric properties can be represented by a resonant effective uniaxial tensor. We found that the band gap properties of the periodic system greatly depend on the volume fraction of nanoparticles in the cholesteric elastomer. In particular, we observed a displacement of the reflection band for quite small fraction volumes whereas for larger values of this fraction there appears a secondary band in the higher frequency region...
December 2017: Physical Review. E
Zachary A Silver, Saravanakumar P Kaliappan, Prasanna Samuel, Srinivasan Venugopal, Gagandeep Kang, Rajiv Sarkar, Sitara S R Ajjampur
BACKGROUND: Soil-transmitted helminth (STH) infections are among the most prevalent neglected tropical diseases (NTD) worldwide. Since the publication of the WHO road map to combat NTD in 2012, there has been a renewed commitment to control STH. In this study, we analysed the geographical distribution and effect of community type on prevalence of hookworm, Trichuris and Ascaris in south Asia and south east Asia. METHODOLOGY: We conducted a systematic review of open-access literature published in PubMed Central and the Global Atlas of Helminth Infection...
January 2018: PLoS Neglected Tropical Diseases
Juan M Martinez-Andrade, Miguel Avalos-Borja, Alfredo R Vilchis-Nestor, Luis O Sanchez-Vargas, Ernestina Castro-Longoria
The chelating and antimicrobial capacity of a novel modification of 17% EDTA with silver nanoparticles (AgNPs) (EDTA-AgNPs) was evaluated in-vitro for root canal treatment (RCT). The EDTA-AgNPs solution was characterized by UV-Vis spectroscopy, ζ-potential and high-resolution transmission electron microscopy (HRTEM). Antimicrobial capacity was evaluated against Candida albicans and Staphylococcus aureus in planktonic and biofilm cells by broth macrodilution (24 h) and XTT assays, (1, 10 and 30 min) respectively...
2018: PloS One
Anike Lockmann, Tillmann Schill, Franziska Hartmann, Lisa-Lena Grönemeyer, Ricarda Holzkamp, Michael P Schön, Kai-Martin Thoms
OBJECTIVE: Given that local elevated protease activity (EPA) has been implicated in impaired wound healing, a prospective single-center study was conducted to assess protease activity in various wound types. METHODS: Protease activity was determined using an easy-to-use test system (Woundchek Protease Status Test Kit; Systagenix, Gatwick, United Kingdom) in 160 wounds in 143 patients. The assay detects the combined activity of inflammatory proteases, mainly matrix metalloproteinases 8 and 9 and human neutrophil elastase...
February 2018: Advances in Skin & Wound Care
Dong Hyuk Kim, Juyoung Lee, Anna Lee
An efficient one-pot approach for the synthesis of diaryl sulfoxides and diaryl sulfones using aryl thiols and aryl diazonium salts was developed. The use of a visible-light-driven silver catalysis and the subsequent singlet-oxygen-induced oxidation enabled selective synthesis of sulfoxides and sulfones in the absence of a photocatalyst. The reactions were carried out under mild reaction conditions; the desired products were obtained under air atmosphere at room temperature.
January 18, 2018: Organic Letters
Jia-Wei Liu, Lei Feng, Haifeng Su, Zhi Wang, Quan-Qin Zhao, Xingpo Wang, Chen-Ho Tung, Di Sun, Lan-Sun Zheng
Although there has been an upsurge of interest in anisotropic assembly of inorganic nanoparticles, atomically precise self-assembly of anisotropic (nonspherical) high-nuclearity metal clusters is extremely rare. Herein, we presented two novel silver nanoclusters, Ag52 (SD/Ag23) and Ag76 (SD/Ag24), which are interiorly templated by five MoO42- and a pair of Mo6O228- anions, respectively, and co-protected by bridging RSH and terminal diphosphine ligands exteriorly. Regiospe-cific distribution diphosphine ligands on the surface and the arrangement of multiple molybdate templates within the nanoclusters synergetically tailor their shapes to anisotropic oblate spheroid and elongated rod, respectively, as opposed to isotropic nanospheres...
January 18, 2018: Journal of the American Chemical Society
Meiying Qie, Jian Lin, Fang Kong, Mark A Silver, Zenghui Yue, Xiaomei Wang, Linjuan Zhang, Hongliang Bao, Thomas E Albrecht-Schmitt, Jian-Qiang Wang
The exploration of phase formation in the f-element-bearing iodate selenate system has resulted in 14 novel rare-earth-containing iodate selenates, Ln(IO3)(SeO4) (Ln = La, Ce, Pr, Nd; LnISeO-1), Ln(IO3)(SeO4)(H2O) (Ln = Sm, Eu; LnISeO-2), and Ln(IO3)(SeO4)(H2O)2·H2O (Ln = Gd, Dy, Ho, Er, Tm, Yb, Lu, Y; LnISeO-3), as well as two new thorium iodate selenates, Th(OH)(IO3)(SeO4)(H2O) (ThISeO-1) and Th(IO3)2(SeO4) (ThISeO-2). LnISeO-3 and ThISeO-2 crystallize in the chiral space group P212121, while LnISeO-1, LnISeO-2, and ThISeO-1 crystallize in the centrosymmetric space group P21/c...
January 18, 2018: Inorganic Chemistry
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