Search results for "Silver"
showing 10 items of 697 documents
Caries arresting effect of silver diamine fluoride on dentine carious lesion with S. mutans and L. acidophilus dual-species cariogenic biofilm
2013
OBJECTIVES: This in vitro study investigated the effects of silver diamine fluoride (SDF) on dentine carious lesion with cariogenic biofilm. STUDY DESIGN: Thirty human dentine blocks were inoculated with Streptococcus mutans and Lactobacillus acidophilus dual-species biofilm to create carious lesion. They were equally divided into test and control group to receive topical application of SDF and water. After incubation anaerobically using micro-well plate at 37oC for 7 days, the biofilms were evaluated for kinetics, morphology and viability by colony forming units (CFU), scanning electron microscopy (SEM), and confocal microscopy (CLSM), respectively. The carious lesion underwent crystal cha…
A monolayer of a Cu2+-tetraazamacrocyclic complex on glass as the adhesive layer for silver nanoparticles grafting, in the preparation of surface-act…
2011
International audience; A silane-derivatized tetraaza Cu2+ macrocyclic complex is prepared, which forms monolayers on glass surfaces, capable of allowing the further deposition of a stable monolayer of silver nanoparticles, obtaining by this, surfaces that display an enhanced antibacterial activity against Staphylococcus aureus and Escherichia coli.
Tansy fruit mediated greener synthesis of silver and gold nanoparticles
2010
Abstract In this paper we have reported the green synthesis of silver (AgNPs) and gold (AuNPs) nanoparticles by reduction of silver nitrate and chloroauric acid solutions, respectively, using fruit extract of Tanacetum vulgare ; commonly found plant in Finland. The process for the synthesis of AgNPs and AuNPs is rapid, novel and ecofriendly. Formation of the AgNPs and AuNPs were confirmed by surface plasmon spectra using UV–Vis spectrophotometer and absorbance peaks at 452 and 546 nm. Different tansy fruit extract concentration (TFE), silver and gold ion concentration, temperature and contact times were experimented in the synthesis of AgNPs and AuNPs. The properties of prepared nanoparticl…
New Tools for Characterizing Metallic Nanoparticles: AgNPs, A Case Study.
2015
Currently, transmission electron microscopy (TEM) is the main technique for estimating the sizes of spherical nanoparticles (NPs) and through them, their concentrations. This paper demonstrates for the first time that C18 reversed-phase capillary liquid chromatography (Cap-LC) coupled to diode array detection (DAD) has the potential to estimate mean concentrations of silver nanoparticles (AgNPs) and thereby determine their average size. Direct injection of the sample without previous extraction or separation steps is carried out. Only a unique standard with a known AgNP size is needed for the calibration. In a first approach, the new method has been tested over silver nanoparticles, produce…
Scalable heterogeneous synthesis of metallic nanoparticles and aggregates with polyvinyl alcohol
2009
Here we report on a new route to synthesize colloidal silver and gold nanoparticles, potentially scalable for massive nanoparticle-production. This method is based on the microwave-assisted heterogeneous reduction of the metal salts with polyvinylalcohol. The reaction is carried out in alcohols, which are non-solvents for polyvinylalcohol. Nanoparticles can be very easily separated by filtration. The reaction kinetics are extremely fast. Size-controlled formation of nanoparticle agglomerates is accomplished with a seed-mediated synthesis of nanoparticles upon MW exposure.
Use of Nanomaterials as Alternative for Controlling Enzymatic Browning in Fruit Juices
2020
Abstract Polyphenol oxidase (PPO) enzyme, present in most of fruits and vegetables, frequently induces browning in juices and beverages during postharvest and processing. Many efforts have been done to prevent or avoid this reaction. Nevertheless, the development of new methods is still of interest since many of the current methods present important drawbacks. An overview of the exiting techniques to inhibit enzymatic browning has been compiled in this chapter, including physical (i.e., thermal treatments, high pressures, irradiation, ultrasonication, pulsed electric fields, and ultrafiltration) and chemical techniques (acidification, addition of antibrowning agents) but with particular att…
Analysis of eicosapentaenoic and docosahexaenoic acid geometrical isomers formed during fish oil deodorization.
2006
International audience; Addition of long-chain polyunsaturated fatty acids (LC-PUFAs) from marine oil into food products implies preliminary refining procedures of the oil which thermal process affects the integrity of LC-PUFAs. Deodorization, the major step involving high temperatures, is a common process used for the refining of edible fats and oils. The present study evaluates the effect of deodorization temperature on the formation of LC-PUFA geometrical isomers. Chemically isomerized eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were used as reference samples. Fish oil samples have been deodorized at 180, 220 and 250 °C for 3 h and pure EPA and DHA fatty acid methyl esters…
Il nobile casato dei Ventimiglia e Donna Felice Ventimiglia Barberini
2017
Nella prima parte del saggio (R.F. Margiotta, Il nobile casato dei Ventimiglia dalla Liguria alla Sicilia) si delinea la storia dei Ventimiglia, provenienti dalla Liguria, insediatisi in Sicilia sin dal Duecento, da Francesco I a Francesco IV Rodrigo, padre di Felice Ventimiglia, e ci si sofferma sulle opere più rappresentative da loro commissionate. Nella seconda parte (M.C. Di Natale, Felice Ventimiglia Barberini dal principato di Castelbuono a Roma) si prende in esame la figura di donna Felice Ventimiglia e se ne ripercorrono le vicende della vita attraverso due significativi documenti: l'inventario dotale della nobildonna, stilato nel 1693, in occasione delle nozze con il principe di pa…
Calcium dicaesium silver thiocyanate dihydrate.
2001
The title compound, CaCs2[Ag2(SCN)6]·2H2O, forms a continuous structure where the Ag atoms form chains with S atoms in the c-axis direction. The chains are bonded together through Cs and Ca atoms. The crystal water of the structure is bonded to the Ca atoms, which lie on centers of symmetry.
Double- and Multi-Calixarentes
2006
Calixarenes are easily (and often selectively) functionalized and therefore they can be combined in various ways to larger molecules containing more than one calixarene substructure. In the following chapter we will try to give an overview on such multicalixarenes held together by "conventional" covalent links. Self-assembled structures are treated separately in Chapter 8. The earliest examples for double calixarenes of importance are the carcerands and hemicarcerands of D. Cram in which two resorcarene derived cavitands are combined. Due to their unique properties to include (more or less permanently) smaller molecules, they are treated separately in Chapter 10. Further combinations of cav…