Polyelectrolyte Multilayer Film Coated Silver Nanorods: An Effective Carrier System for Externally Activated Drug Delivery

Science.gov (United States)

Paramasivam, Gokul; Sharma, Varsha; Sundaramurthy, Anandhakumar

2017-08-01

Nanoparticle anisotropy offers unique functions and features in comparison with spherical nanoparticles (NPs) and makes anisotropic nanoparticles (ANPs) promising candidates in applications like drug delivery, imaging, biosensing and theranostics. Presence of surface active groups (e.g. amine, and carboxylate groups) on their surface provides binding sites for ligands or other biomolecules, and hence, this could be targeted for specific part or cells in our body. In the quest of such surface modification, functionalization of ANPs along Layer-by-Layer (LbL) coating of oppositely charged polyelectrolytes (PE) reduces cellular toxicity and promotes easy encapsulation of drugs. In this work, we report the silver nanorods (AgNRs) synthesis by adsorbate directed synthetic approach using cetyltrimethyl ammonium bromide (CTAB). The formed ANPs is investigated by scanning electron microscopy (SEM) and UV-Visible (UV-Vis) spectroscopy revealing the shaping of AgNRs of 3-16 nm aspect ratio with some presence of triangles. These NRs were further coated with bio polymers of chitosan (CH) and dextran sulphate (DS) through LbL approach and used for encapsulation of water soluble anti-bacterial drugs like ciprofloxacin hydrochloride (CFH). The encapsulation of drugs and profiles of drug release were investigated and compared to that of spherical silver nanoparticles (AgNPs). The added advantages of the proposed drug delivery system (DDS) can be externally activated to release the loaded drug and used as contrast agents for biological imaging under exposure to NIR light. Such system shows unique and attractive characteristics required for drug delivery and bioimaging thus offering the scope for further development as theranostic material.

21 CFR 524.802 - Enrofloxacin, silver sulfadiazine emulsion.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Enrofloxacin, silver sulfadiazine emulsion. 524... ANIMAL DRUGS § 524.802 Enrofloxacin, silver sulfadiazine emulsion. (a) Specifications. Each milliliter contains 5 milligrams (mg) enrofloxacin and 10 mg silver sulfadiazine. (b) Sponsor. See No. 000859 in § 510...

Antibacterial properties and mechanisms of gold-silver nanocages

Science.gov (United States)

Wang, Yulan; Wan, Jiangshan; Miron, Richard J.; Zhao, Yanbin; Zhang, Yufeng

2016-05-01

Despite the number of antibiotics used in routine clinical practice, bacterial infections continue to be one of the most important challenges faced in humans. The main concerns arise from the continuing emergence of antibiotic-resistant bacteria and the difficulties faced with the pharmaceutical development of new antibiotics. Thus, advancements in the avenue of novel antibacterial agents are essential. In this study, gold (Au) was combined with silver (Ag), a well-known antibacterial material, to form silver nanoparticles producing a gold-silver alloy structure with hollow interiors and porous walls (gold-silver nanocage). This novel material was promising in antibacterial applications due to its better biocompatibility than Ag nanoparticles, potential in photothermal effects and drug delivery ability. The gold-silver nanocage was then tested for its antibacterial properties and the mechanism involved leading to its antibacterial properties. This study confirms that this novel gold-silver nanocage has broad-spectrum antibacterial properties exerting its effects through the destruction of the cell membrane, production of reactive oxygen species (ROS) and induction of cell apoptosis. Therefore, we introduce a novel gold-silver nanocage that serves as a potential nanocarrier for the future delivery of antibiotics.

Drugs@FDA: FDA Approved Drug Products

Science.gov (United States)

... Cosmetics Tobacco Products Home Drug Databases Drugs@FDA Drugs@FDA: FDA Approved Drug Products Share Tweet Linkedin Pin it More sharing ... Download Drugs@FDA Express for free Search by Drug Name, Active Ingredient, or Application Number Enter at ...

Characterization of silver nanoparticles in selected consumer products and its relevance for predicting children’s potential exposures

Science.gov (United States)

Tulve, Nicolle S.; Stefaniak, Aleksandr B.; Vance, Marina E.; Rogers, Kim; Mwilu, Samuel; LeBouf, Ryan F.; Schwegler-Berry, Diane; Willis, Robert; Thomas, Treye A.; Marr, Linsey C.

2015-01-01

Due to their antifungal, antibacterial, antiviral, and antimicrobial properties, silver nanoparticles (AgNPs) are used in consumer products intended for use by children or in the home. Children may be especially affected by the normal use of consumer products because of their physiological functions, developmental stage, and activities and behaviors. Despite much research to date, children’s potential exposures to AgNPs are not well characterized. Our objectives were to characterize selected consumer products containing AgNPs and to use the data to estimate a child’s potential non-dietary ingestion exposure. We identified and cataloged 165 consumer products claiming to contain AgNPs that may be used by or near children or found in the home. Nineteen products (textile, liquid, plastic) were selected for further analysis. We developed a tiered analytical approach to determine silver content, form (particulate or ionic), size, morphology, agglomeration state, and composition. Silver was detected in all products except one sippy cup body. Among products in a given category, silver mass contributions were highly variable and not always uniformly distributed within products, highlighting the need to sample multiple areas of a product. Electron microscopy confirmed the presence of AgNPs. Using this data, a child’s potential non-dietary ingestion exposure to AgNPs when drinking milk formula from a sippy cup is 1.53 μg Ag/kg. Additional research is needed to understand the number and types of consumer products containing silver and the concentrations of silver in these products in order to more accurately predict children’s potential aggregate and cumulative exposures to AgNPs. PMID:25747543

Synthesis of sulfadiazine and silver sulfadiazine in semi-micro scale, as an experimental practice in drug synthesis

International Nuclear Information System (INIS)

Borges, Aurea Donizete Lanchote; Del Ponte, Gino; Federman Neto, Alberto; Carvalho, Ivone

2005-01-01

The total synthesis of sulfadiazine and silver sulfadiazine from readily available starting materials was adapted to semi-micro laboratory scale and is proposed as an experiment in drug synthesis for undergraduate courses. (author)

Silver nanoparticle toxicity to retinal pigment epithelial cells in vitro is influenced by particle size and coating, but not UVA radiation

Science.gov (United States)

Silver nanoparticles (AgNP) are being introduced into textiles, medical devices, cleaning/disinfecting products and other goods because of their antibiotic properties. Some nanomaterials, including silver, have been developed into drug delivery systems that can be administered di...

Leaching of Silver from Silver-Impregnated Food Storage Containers

Science.gov (United States)

Hauri, James F.; Niece, Brian K.

2011-01-01

The use of silver in commercial products has proliferated in recent years owing to its antibacterial properties. Food containers impregnated with micro-sized silver promise long food life, but there is some concern because silver can leach out of the plastic and into the stored food. This laboratory experiment gives students the opportunity to…

Green synthesis of silver nanoparticles by Escherichia coli : Analysis of antibacterial activity

Directory of Open Access Journals (Sweden)

Koilparambil Divya

2016-07-01

Full Text Available The emerging infectious diseases and the development of drug resistance in the pathogenic microorganism is a matter of serious concern. Despite the increased knowledge of microbial pathogenesis and application of modern therapeutics, the morbidity and mortality associated with the microbial infections still remains high. Therefore, there is a pressing demand to discover novel strategies and identify new antimicrobial agents to develop the next generation of drugs or agents to control microbial infections. The use of nanoparticles is gaining impetus in the present century as they possess defined chemical, optical and mechanical properties. In the present study green synthesis of silver nanoparticles by Escherichia coli has been done. Various parameters such as mixing ratio of culture supernatant and silver nitrate, media, temperature and pH for production of silver nanoparticles were optimised. The nanoparticles synthesised was characterized using SEM, FTIR and XRD. The antibacterial activity of silver nanoparticles synthesised using both pellet and supernatant against human pathogens Salmonella typhi, Vibrio cholerae, Bacillus subtilis and Klebsiella pneumoniae was analysed and MIC was calculated as 20µg and 50µg respectively.

Analysis of silver nanoparticles in antimicrobial products using surface-enhanced Raman spectroscopy (SERS).

Science.gov (United States)

Guo, Huiyuan; Zhang, Zhiyun; Xing, Baoshan; Mukherjee, Arnab; Musante, Craig; White, Jason C; He, Lili

2015-04-07

Silver nanoparticles (AgNPs) are the most commonly used nanoparticles in consumer products. Concerns over human exposure to and risk from these particles have resulted in increased interest in novel strategies to detect AgNPs. This study investigated the feasibility of surface-enhanced Raman spectroscopy (SERS) as a method for the detection and quantification of AgNPs in antimicrobial products. By using ferbam (ferric dimethyl-dithiocarbamate) as an indicator molecule that binds strongly onto the nanoparticles, AgNPs detection and discrimination were achieved based on the signature SERS response of AgNPs-ferbam complexes. SERS response with ferbam was distinct for silver ions, silver chloride, silver bulk particles, and AgNPs. Two types of AgNPs with different coatings, citrate and polyvinylpirrolidone (PVP), both showed strong interactions with ferbam and induced strong SERS signals. SERS was effectively applicable for detecting Ag particles ranging from 20 to 200 nm, with the highest signal intensity in the 60-100 nm range. A linear relationship (R(2) = 0.9804) between Raman intensity and citrate-AgNPs concentrations (60 nm; 0-20 mg/L) indicates the potential for particle quantification. We also evaluated SERS detection of AgNPs in four commercially available antimicrobial products. Combined with ICP-MS and TEM data, the results indicated that the SERS response is primarily dependent on size, but also affected by AgNPs concentration. The findings demonstrate that SERS is a promising analytical platform for studying environmentally relevant levels of AgNPs in consumer products and related matrices.

One-step flame synthesis of silver nanoparticles for roll-to-roll production of antibacterial paper

Science.gov (United States)

Brobbey, Kofi J.; Haapanen, Janne; Gunell, Marianne; Mäkelä, Jyrki M.; Eerola, Erkki; Toivakka, Martti; Saarinen, Jarkko J.

2017-10-01

Nanoparticles are used in several applications due to the unique properties they possess compared to bulk materials. Production techniques have continuously evolved over the years. Recently, there has been emphasis on environmentally friendly manufacturing processes. Substrate properties often limit the possible production techniques and, for example; until recently, it has been difficult to incorporate nanoparticles into paper. Chemical reduction of a precursor in the presence of paper changes the bulk properties of paper, which may limit intended end-use. In this study, we present a novel technique for incorporating silver nanoparticles into paper surface using a flame pyrolysis procedure known as Liquid Flame Spray. Papers precoated with mineral pigments and plastic are used as substrates. Silver nanoparticles were analyzed using SEM and XPS measurements. Results show a homogeneous monolayer of silver nanoparticles on the surface of paper, which demonstrated antibacterial properties against E. coli. Paper precoated with plastic showed more nanoparticles on the surface compared to pigment coated paper samples except for polyethylene-precoated paper. The results demonstrate a dry synthesis approach for depositing silver nanoparticles directly onto paper surface in a process which produces no effluents. The production technique used herein is up scalable for industrial production of antibacterial paper.

Synthesis of silver nanoparticles using medicinal Zizyphus xylopyrus bark extract

Science.gov (United States)

Sumi Maria, Babu; Devadiga, Aishwarya; Shetty Kodialbail, Vidya; Saidutta, M. B.

2015-08-01

In the present paper, biosynthesis of silver nanoparticles using Zizyphus xylopyrus bark extract is reported. Z. xylopyrus bark extract is efficiently used for the biosynthesis of silver nanoparticles. UV-Visible spectroscopy showed surface plasmon resonance peaks in the range 413-420 nm confirming the formation of silver nanoparticles. Different factors affecting the synthesis of silver nanoparticles like methodology for the preparation of extract, concentration of silver nitrate solution used for biosynthesis and initial pH of the reaction mixture were studied. The extract prepared with 10 mM AgNO3 solution by reflux extraction method at optimum initial pH of 11, resulted in higher conversion of silver ions to silver nanoparticles as compared with those prepared by open heating or ultrasonication. SEM analysis showed that the biosynthesized nanoparticles are spherical in nature and ranged from 60 to 70 nm in size. EDX suggested that the silver nanoparticles must be capped by the organic components present in the plant extract. This simple process for the biosynthesis of silver nanoparticles using aqueous extract of Z. xylopyrus is a green technology without the usage of hazardous and toxic solvents and chemicals and hence is environment friendly. The process has several advantages with reference to cost, compatibility for its application in medical and drug delivery, as well as for large-scale commercial production.

Production of porous filter elements from PEUAPM nanocomposites and silver nanoparticles

International Nuclear Information System (INIS)

Bizzo, M.A.; Hui, W.S.

2014-01-01

The production of filter elements for water based in polymers is widespread in the market, but has an undesirable characteristic: they are not efficient and able to retain or eliminate microorganisms at all times. This paper proposes to produce nanocomposite filters with biocidal properties composed of ultra-high molecular weight polyethylene(UHMWPE) and silver nanoparticles, the UHMWPE is responsible for the uniform porous structure of the filters and the silver nanoparticles incorporated on the polymer are responsible for the biocide action. Particulate polymer that presents a different particle size curve was used for sintering the filters. Samples of filter elements obtained in this work were characterized by the techniques of X-ray diffraction, scanning electron microscopy and EDS microanalysis. The results indicated a porosity of approximately 49% in the filter, and the formation of the nanocomposite. key-words: nanocomposites, silver, UHMWPE, filter elements. (author)

Biosorption of silver cations onto Lactococcus lactis and Lactobacillus casei isolated from dairy products.

Directory of Open Access Journals (Sweden)

Maciej Milanowski

Full Text Available The current work deals with the phenomenon of silver cations uptake by two kinds of bacteria isolated from dairy products. The mechanism of sorption of silver cations by Lactococcus lactis and Lactobacillus casei bacteria was investigated. Inductively coupled plasma-mass spectrometry (ICP-MS was used for determination of silver concentration sorbed by bacteria. Analysis of charge distribution was conducted by diffraction light scattering method. Changes in the ultrastructure of Lactococcus lactis and Lactobacillus casei cells after treatment with silver cations were investigated using transmission electron microscopy observation. Molecular spectroscopy methods, namely Fourier transform-infrared spectroscopy (FT-IR and matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS were employed for description of the sorption mechanism. Moreover, an analysis of volatile organic compounds (VOCs extracted from bacterial cells was performed.

Thermal decomposition process of silver behenate

International Nuclear Information System (INIS)

Liu Xianhao; Lu Shuxia; Zhang Jingchang; Cao Weiliang

2006-01-01

The thermal decomposition processes of silver behenate have been studied by infrared spectroscopy (IR), X-ray diffraction (XRD), combined thermogravimetry-differential thermal analysis-mass spectrometry (TG-DTA-MS), transmission electron microscopy (TEM) and UV-vis spectroscopy. The TG-DTA and the higher temperature IR and XRD measurements indicated that complicated structural changes took place while heating silver behenate, but there were two distinct thermal transitions. During the first transition at 138 deg. C, the alkyl chains of silver behenate were transformed from an ordered into a disordered state. During the second transition at about 231 deg. C, a structural change took place for silver behenate, which was the decomposition of silver behenate. The major products of the thermal decomposition of silver behenate were metallic silver and behenic acid. Upon heating up to 500 deg. C, the final product of the thermal decomposition was metallic silver. The combined TG-MS analysis showed that the gas products of the thermal decomposition of silver behenate were carbon dioxide, water, hydrogen, acetylene and some small molecule alkenes. TEM and UV-vis spectroscopy were used to investigate the process of the formation and growth of metallic silver nanoparticles

Silver enhances antibiotic activity against gram-negative bacteria.

Science.gov (United States)

Morones-Ramirez, J Ruben; Winkler, Jonathan A; Spina, Catherine S; Collins, James J

2013-06-19

A declining pipeline of clinically useful antibiotics has made it imperative to develop more effective antimicrobial therapies, particularly against difficult-to-treat Gram-negative pathogens. Silver has been used as an antimicrobial since antiquity, yet its mechanism of action remains unclear. We show that silver disrupts multiple bacterial cellular processes, including disulfide bond formation, metabolism, and iron homeostasis. These changes lead to increased production of reactive oxygen species and increased membrane permeability of Gram-negative bacteria that can potentiate the activity of a broad range of antibiotics against Gram-negative bacteria in different metabolic states, as well as restore antibiotic susceptibility to a resistant bacterial strain. We show both in vitro and in a mouse model of urinary tract infection that the ability of silver to induce oxidative stress can be harnessed to potentiate antibiotic activity. Additionally, we demonstrate in vitro and in two different mouse models of peritonitis that silver sensitizes Gram-negative bacteria to the Gram-positive-specific antibiotic vancomycin, thereby expanding the antibacterial spectrum of this drug. Finally, we used silver and antibiotic combinations in vitro to eradicate bacterial persister cells, and show both in vitro and in a mouse biofilm infection model that silver can enhance antibacterial action against bacteria that produce biofilms. This work shows that silver can be used to enhance the action of existing antibiotics against Gram-negative bacteria, thus strengthening the antibiotic arsenal for fighting bacterial infections.

Electrically Conductive Silver Paste Obtained by Use of Silver Neodecanoate as Precursor

Science.gov (United States)

Shen, Longguang; Liu, Jianguo; Zeng, Xiaoyan; Ren, Zhao

2015-02-01

An electrically conductive silver paste has been prepared from an organometallic compound, silver neodecanoate, as silver precursor. The precursor was highly soluble in organic solvents and decomposed into metallic silver at low sintering temperatures (writing process, enabling production of silver lines on a substrate. The electrical resistivity of the silver lines was 9 × 10-6 Ω cm after sintering at 115°C for 60 min, 5.8 × 10-6 Ω cm when sintered at 150°C for 60 min, and 3 × 10-6 Ω cm when sintered above 300°C, values which are similar to those of bulk silver. Hence, the prepared paste can be successfully used on flexible substrates such as polymers.

Mercury Production and Use in Colonial Andean Silver Production: Emissions and Health Implications

Science.gov (United States)

Hagan, Nicole A.

2012-01-01

Background: Colonial cinnabar mining and refining began in Huancavelica, Peru, in 1564. With a local source of mercury, the amalgamation process was adopted to refine silver in Potosí, Bolivia, in the early 1570s. As a result, large quantities of mercury were released into the environment. Objectives: We used archival, primary, and secondary sources to develop the first estimate of mercury emissions from cinnabar refining in Huancavelica and to revise previous estimates of emissions from silver refining in Potosí during the colonial period (1564–1810). Discussion: Although other estimates of historical mercury emissions have recognized Potosí as a significant source, Huancavelica has been overlooked. In addition, previous estimates of mercury emissions from silver refining under-estimated emissions because of unrecorded (contra-band) production and volatilization of mercury during processing and recovery. Archival descriptions document behavioral and health issues during the colonial period that are consistent with known effects of mercury intoxication. Conclusions: According to our calculations, between 1564 and 1810, an estimated 17,000 metric tons of mercury vapor were emitted from cinnabar smelting in Huancavelica, and an estimated 39,000 metric tons were released as vapor during silver refining operations in Potosí. Huancavelica and Potosí combined contributed > 25% of the 196,000 metric tons of mercury vapor emissions in all of Latin America between 1500 and 1800. The historical record is laden with evidence of mercury intoxication consistent with effects recognized today. Our estimates serve as the foundation of investigations of present-day contamination in Huancavelica and Potosí resulting from historical emissions of mercury. PMID:22334094

Photostability and Photostabilization of Drugs and Drug Products

Directory of Open Access Journals (Sweden)

Iqbal Ahmad

2016-01-01

Full Text Available Photostability studies of drugs and drug products are an integral part of the product development process in the pharmaceutical industry. These studies are carried out to ensure quality, efficacy, and safety of the formulated products during manufacture, storage, and use. This review deals with the concept of photostability and related aspects and the literature available in the field. It highlights the role of the photochemistry in the photostability studies, describes the functional groups important for the photoreactivity of drugs, explains photophysical processes, and deals with the kinetics of photochemical reactions. The various modes of photodegradation of drugs with examples of selected compounds are presented. The biological consequences of the effect of light on the drug degradation are described. The photostability testing of drugs and drug products and the requirements under ICH guideline are discussed. Some information on the packaging requirements for the formulated products is provided. The various methods used for the photostabilization of solid and liquid dosage forms are also discussed.

Antituberculous effect of silver nanoparticles

International Nuclear Information System (INIS)

Kreytsberg, G N; Gracheva, I E; Kibrik, B S; Golikov, I V

2011-01-01

The in vitro experiment, involving 1164 strains of the tuberculosis mycobacteria, exhibited a potentiating effect of silver nanoparticles on known antituberculous preparations in respect of overcoming drug-resistance of the causative agent. The in vitro experiment, based on the model of resistant tuberculosis, was performed on 65 white mice. An evident antituberculous effect of the nanocomposite on the basis of silver nanoparticles and isoniazid was proved. Toxicological assessment of the of nanopreparations was carried out. The performed research scientifically establishes efficacy and safety of the nanocomposite application in combination therapy of patients suffering from drug-resistant tuberculosis.

Antituberculous effect of silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Kreytsberg, G N; Gracheva, I E [Limited Liability Company ' Scientific and Production Association (NPO)' Likom' , 150049, Yaroslavl, Magistralnaya str., 32 (Russian Federation); Kibrik, B S [Yaroslavl State Medical Academy Russia, 150000, Yaroslavl, Revolutsionnaya str., 5 (Russian Federation); Golikov, I V, E-mail: likomm@yaroslavl.ru [Yaroslavl State Technical University Russia, 150023, Yaroslavl, Moskovskiy avenue, 88 (Russian Federation)

2011-04-01

The in vitro experiment, involving 1164 strains of the tuberculosis mycobacteria, exhibited a potentiating effect of silver nanoparticles on known antituberculous preparations in respect of overcoming drug-resistance of the causative agent. The in vitro experiment, based on the model of resistant tuberculosis, was performed on 65 white mice. An evident antituberculous effect of the nanocomposite on the basis of silver nanoparticles and isoniazid was proved. Toxicological assessment of the of nanopreparations was carried out. The performed research scientifically establishes efficacy and safety of the nanocomposite application in combination therapy of patients suffering from drug-resistant tuberculosis.

Impact of silver ions and silver nanoparticles on the plant growth and soil microorganisms

Directory of Open Access Journals (Sweden)

D. Tomacheski

2017-12-01

Full Text Available There is a growing consumer market for products that proclaim to decrease microorganism counts to prevent infections. Most of these products are loaded with silver in its ionic or nanoparticle form. Through use or during production, these particles can find their way into the soil and cause an impact in microbial and plant communities. This study aims to evaluate the impact of silver based particles in Avena byzantina (oat, Lactuca sativa (lettuce and Raphanus sativus (radish development and in the soil microorganism abundance. Oat, lettuce and radish plants were cultivated in soil contaminated with particles of bentonite organomodified with silver (Ag+_bentonite, silver phosphate glass (Ag+_phosphate and silver nanoparticles adsorbed on fumed silica (AgNp_silica. Plant development and microorganisms’ abundance were evaluated. To some degree, Ag+_bentonite impacted plants development and AgNp_silica causes an adverse effect on microbial abundance. The impact on plants and microorganisms was contradictory and varied according to soil and particles physicochemical characteristics.

Mineral commodity profiles: Silver

Science.gov (United States)

Butterman, W.C.; Hilliard, Henry E.

2005-01-01

Overview -- Silver is one of the eight precious, or noble, metals; the others are gold and the six platinum-group metals (PGM). World mine production in 2001 was 18,700 metric tons (t) and came from mines in 60 countries; the 10 leading producing countries accounted for 86 percent of the total. The largest producer was Mexico, followed by Peru, Australia, and the United States. About 25 percent of the silver mined in the world in 2001 came from silver ores; 15 percent, from gold ores and the remaining 60 percent, from copper, lead, and zinc ores. In the United States, 14 percent of the silver mined in 2001 came from silver ores; 39 percent, from gold ores; 10 percent, from copper and copper-molybdenum ores; and 37 percent, from lead, zinc, and lead-zinc ores. The precious metal ores (gold and silver) came from 30 lode mines and 10 placer mines; the base-metal ores (copper, lead, molybdenum, and zinc) came from 24 lode mines. Placer mines yielded less than 1 percent of the national silver production. Silver was mined in 12 States, of which Nevada was by far the largest producer; it accounted for nearly one-third of the national total. The production of silver at domestic mines generated employment for about 1,100 mine and mill workers. The value of mined domestic silver was estimated to be $290 million. Of the nearly 27,000 t of world silver that was fabricated in 2001, about one-third went into jewelry and silverware, one-fourth into the light-sensitive compounds used in photography, and nearly all the remainder went for industrial uses, of which there were 7 substantial uses and many other small-volume uses. By comparison, 85 percent of the silver used in the United States went to photography and industrial uses, 8 percent to jewelry and silverware, and 7 percent to coins and medals. The United States was the largest consumer of silver followed by India, Japan, and Italy; the 13 largest consuming countries accounted for nearly 90 percent of the world total. In the

Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

International Nuclear Information System (INIS)

Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A.; Landero-Figueroa, Julio

2014-01-01

The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV–VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag + ) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg −1 detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm

Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

Energy Technology Data Exchange (ETDEWEB)

Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A., E-mail: joseph.caruso@uc.edu; Landero-Figueroa, Julio

2014-10-01

The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV–VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag{sup +}) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg{sup −1} detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm.

Direct evidence of 1,900 years of indigenous silver production in the Lake Titicaca Basin of Southern Peru.

Science.gov (United States)

Schultze, Carol A; Stanish, Charles; Scott, David A; Rehren, Thilo; Kuehner, Scott; Feathers, James K

2009-10-13

Archaeological excavations at a U-shaped pyramid in the northern Lake Titicaca Basin of Peru have documented a continuous 5-m-deep stratigraphic sequence of metalworking remains. The sequence begins in the first millennium AD and ends in the Spanish Colonial period ca. AD 1600. The earliest dates associated with silver production are 1960 + or - 40 BP (2-sigma cal. 40 BC to AD 120) and 1870 + or - 40 BP (2-sigma cal. AD 60 to 240) representing the oldest known silver smelting in South America. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis of production debris indicate a complex, multistage, high temperature technology for producing silver throughout the archaeological sequence. These data hold significant theoretical implications including the following: (i) silver production occurred before the development of the first southern Andean state of Tiwanaku, (ii) the location and process of silverworking remained consistent for 1,500 years even though political control of the area cycled between expansionist states and smaller chiefly polities, and (iii) that U-shaped structures were the location of ceremonial, residential, and industrial activities.

Distribution of silver in rats following 28 days of repeated oral exposure to silver nanoparticles or silver acetate

DEFF Research Database (Denmark)

Löschner, Katrin; Hadrup, Niels; Qvortrup, Klaus

2011-01-01

Background: The study investigated the distribution of silver after 28 days repeated oral administration of silver nanoparticles (AgNPs) and silver acetate (AgAc) to rats. Oral administration is a relevant route of exposure because of the use of silver nanoparticles in products related to food...... and food contact materials. Results: AgNPs were synthesized with a size distribution of 14 ± 4 nm in diameter (90% of the nanoparticle volume) and stabilized in aqueous suspension by the polymer polyvinylpyrrolidone (PVP). The AgNPs remained stable throughout the duration of the 28-day oral toxicity study...... in rats. The organ distribution pattern of silver following administration of AgNPs and AgAc was similar. However the absolute silver concentrations in tissues were lower following oral exposure to AgNPs. This was in agreement with an indication of a higher fecal excretion following administration of Ag...

Nano-silver in drinking water and drinking water sources: stability and influences on disinfection by-product formation.

Science.gov (United States)

Tugulea, A-M; Bérubé, D; Giddings, M; Lemieux, F; Hnatiw, J; Priem, J; Avramescu, M-L

2014-10-01

Nano-silver is increasingly used in consumer products from washing machines and refrigerators to devices marketed for the disinfection of drinking water or recreational water. The nano-silver in these products may be released, ending up in surface water bodies which may be used as drinking water sources. Little information is available about the stability of the nano-silver in sources of drinking water, its fate during drinking water disinfection processes, and its interaction with disinfection agents and disinfection by-products (DBPs). This study aims to investigate the stability of nano-silver in drinking water sources and in the finished drinking water when chlorine and chloramines are used for disinfection and to observe changes in the composition of DBPs formed when nano-silver is present in the source water. A dispersion of nano-silver particles (10 nm; PVP-coated) was used to spike untreated Ottawa River water, treated Ottawa River water, organic-free water, and a groundwater at concentrations of 5 mg/L. The diluted dispersions were kept under stirred and non-stirred conditions for up to 9 months and analyzed weekly using UV absorption to assess the stability of the nano-silver particles. In a separate experiment, Ottawa River water containing nano-silver particles (at 0.1 and 1 mg/L concentration, respectively) was disinfected by adding sodium hypochlorite (a chlorinating agent) in sufficient amounts to maintain a free chlorine residual of approximately 0.4 mg/L after 24 h. The disinfected drinking water was then quenched with ascorbic acid and analyzed for 34 neutral DBPs (trihalomethanes, haloacetonitriles, haloacetaldehydes, 1,1 dichloro-2-propanone, 1,1,1 trichloro-2-propanone, chloropicrin, and cyanogen chloride). The results were compared to the profile of DBPs obtained under the same conditions in the absence of nano-silver and in the presence of an equivalent concentration of Ag(+) ions (as AgNO3). The stability of the nano-silver dispersions in

Antibiotic-loaded, silver core-embedded mesoporous silica nanovehicles as a synergistic antibacterial agent for the treatment of drug-resistant infections.

Science.gov (United States)

Wang, Yao; Ding, Xiali; Chen, Yuan; Guo, Mingquan; Zhang, Yan; Guo, Xiaokui; Gu, Hongchen

2016-09-01

Drug-resistant bacterial infections have become one of the most serious risks in public health as they make the conventional antibiotics less efficient. There is an urgent need for developing new generations of antibacterial agents in this field. In this work, a nanoplatform of LEVO-loaded and silver core-embedded mesoporous silica nanovehicles (Ag@MSNs@LEVO) is demonstrated as a synergistic antibacterial agent for the treatment of drug-resistant infections both in vitro and in vivo. The combination of the inner Ag core and the loaded antibiotic drug in mesopores endows the single-particle nanoplatform with a synergistic effect on killing the drug-resistant bacteria. The nanoplatform of Ag@MSNs@LEVO exhibits superior antibacterial activity to LEVO-loaded MSNs (MSNs@LEVO) and silver core-embedded MSNs (Ag@MSNs) in vitro. In the in vivo acute peritonitis model, the infected drug-resistant Escherichia coli GN102 in peritoneal cavity of the mice is reduced by nearly three orders of magnitude and the aberrant pathological feature of spleen and peritoneum disappears after treatment with Ag@MSNs@LEVO. Importantly, this nanopaltform renders no obvious toxic side effect to the mice during the tested time. There is no doubt that this study strongly indicates a promising potential of Ag@MSNs@LEVO as a synergistic and safety therapy tool for the clinical drug-resistant infections. Copyright © 2016 Elsevier Ltd. All rights reserved.

Integrating sustainable biofuel and silver nanomaterial production for in situ upgrading of cellulosic biomass pyrolysis

International Nuclear Information System (INIS)

Xue, Junjie; Dou, Guolan; Ziade, Elbara; Goldfarb, Jillian L.

2017-01-01

Graphical abstract: Integrated production of biotemplated nanomaterials and upgraded biofuels (solid lines indicate current processes, dashed lines indicated proposed pathway). - Highlights: • Novel integrated process to co-produce nanomaterials and biofuels via pyrolysis. • Impregnation of biomass with silver nitrate upgrades bio-oil during pyrolysis. • Co-synthesis enhances syngas produced with more hydrogen. • Biomass template impacts bio-fuels and morphology of resulting nanomaterials. - Abstract: Replacing fossil fuels with biomass-based alternatives is a potential carbon neutral, renewable and sustainable option for meeting the world’s growing energy demand. However, pyrolytic conversions of biomass-to-biofuels suffer marginal total energy gain, and technical limitations such as bio-oils’ high viscosity and oxygen contents that result in unstable, corrosive and low-value fuels. This work demonstrates a new integrated biorefinery process for the co-production of biofuels and silver nanomaterials. By impregnating pure cellulose and corn stalk with silver nitrate, followed by pyrolysis, the gas yield (especially hydrogen) increases substantially. The condensable bio-oil components of the impregnated samples are considerably higher in furfurals (including 5-hydroxymethylfurfural). Though the overall activation energy barrier, as determined via the Distributed Activation Energy Model, does not change significantly with the silver nitrate pre-treatment, the increase in gases devolatilized, and improved 5-hydroxymethylfurfural yield, suggest a catalytic effect, potentially increasing decarboxylation reactions. After using this metal impregnation to improve pyrolysis fuel yield, following pyrolysis, the silver-char composite materials are calcined to remove the biomass template to yield silver nanomaterials. While others have demonstrated the ability to biotemplate such nanosilver on cellulosic biomass, they consider only impregnation and oxidation of the

USE OF SILVER IONS IN PASTEURIZED MILK PRODUCTION

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A. Mamaev

2012-10-01

Full Text Available The means of pasteurized milk shelf life prolongation by electro-chemical diffusion of silver ions has been introduced. Three samples of pasteurized milk were test subjects. In the course of study the following data have been examined: organoleptic, physicochemical, microbiological parameters of check samples and pilot samples of raw and pasteurized milk. Its shelf life has been determined. It has been determined that the test results of raw and pasteurized milk samples processed by various concentration of silver ions showed minor difference in organoleptic, physic-chemical, microbiological parameters and shelf life span. In this connection it appears reasonable to use the smallest concentration of silver ions - 50 micrograms per liter for milk shelf life prolongation as it is considered the least harmful for person's organism. Infusion of silver ions in the concentration of 50 micrograms per liter allows to prolong raw and pasteurized milk shelf life by two days.

Antimicrobial effects of silver zeolite, silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms

Institute of Scientific and Technical Information of China (English)

Sirikamon Saengmee-anupharb; Toemsak Srikhirin; Boonyanit Thaweboon; Sroisiri Thaweboon; Taweechai Amornsakchai; Surachai Dechkunakorn; Theeralaksna Suddhasthira

2013-01-01

Objective: To evaluate the antimicrobial activities of silver inorganic materials, including silver zeolite (AgZ), silver zirconium phosphate silicate (AgZrPSi) and silver zirconium phosphate (AgZrP), against oral microorganisms. In line with this objective, the morphology and structure of each type of silver based powders were also investigated. Methods: The antimicrobial activities of AgZ, AgZrPSi and AgZrP were tested against Streptococcus mutans, Lactobacillus casei, Candidaalbicans and Staphylococcus aureus using disk diffusion assay as a screening test. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the modified membrane method. Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials. Results: All forms of silver inorganic materials could inhibit the growth of all test microorganisms. The MIC of AgZ, AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0-60.0 g/L. In terms of morphology and structure, AgZrPSi and AgZrP had smaller sized particles (1.5-3.0 µm) and more uniformly shaped than AgZ. Conclusions: Silver inorganic materials in the form of AgZ, AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers. These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection.

Antimicrobial effects of silver zeolite,silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms

Institute of Scientific and Technical Information of China (English)

Sirikamon; Saengmee-anupharb; Toemsak; Srikhirin; Boonyanit; Thaweboon; Sroisiri; Thaweboon; Taweechai; Amornsakchai; Surachai; Dechkunakorn; Theeralaksna; Suddhasthira

2013-01-01

Objective:To evaluate the antimicrobial activities of silver inorganic materials,including silver zeolite(AgZ),silver zirconium phosphate silicate(AgZrPSi)and silver zirconium phosphate(AgZrp),against oral microorganisms.In line with this objective,the morphology and structure of each type of silver based powders were also investigated.Methods:The antimicrobial activities of AgZ,AgZrPSi and AgZrP were tested against Streptococcus mutans,Lactobacillus casei,Candida albicans and Staphylococcus aureus using disk diffusion assay as a screening test.The minimum inhibitory concentration(MIC)and minimum lethal concentration(MLC)were determined using the modified membrane method.Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials.Results:All forms of silver inorganic materials could inhibit the growth of all test microorganisms.The MIC of AgZ,AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0-60.0 g/L.In terms of morphology and structure.AgZrPSi and AgZrP had smaller sized particles(1.5-3.0μm)and more uniformly shaped than AgZ.Conclusions:Silver inorganic materials in the form of AgZ,AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers.These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection.

Determination of silver and cerium in the liver and the kidney from a severely burned infant treated with silver sulfadiazine and cerium nitrate

International Nuclear Information System (INIS)

Hirakawa, Keiko

1983-01-01

Silver and cerium in the liver and the kidney from severely burned infant were analyzed by neutron activation method. The patient was treated topically with cerium nitrate/silver sulfadiazine cream and cerium nitrate solution for 3 months. Then, the treatment with these drugs was stopped because o f abdominal distention. The patient died 1 month after the cessation of the treatment with these drugs. The tissue specimens, blank liver sample and reference standards were irradiated with TRIGA MARK II Reactor of Rikkyo University. About 1 month after the irradiation, the activities were measured with a Ge(Li) detector coupled to a 4096 channel pulse height analyzer. A large amount of silver was detected both in the liver and in the kidney and a trace of cerium only in the liver. A considerable amount of silver was detected in the liver and its quantity was about 1600 times more than that of normal livers reported by Hamilton, Minski and Cleary (1972 -- 73). Neither silver nor cerium were detected in the blank liver. These results suggest that prolonged topical chemotherapy of cerium nitrate/silver sulfadiazine cream and cerium nitrate solution for the extensive burn injuries causes considerable absorption of silver and cerium into the liver and the kidney. (author)

Toxicological Assessment of a Lignin Core Nanoparticle Doped with Silver as an Alternative to Conventional Silver Core Nanoparticles

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Cassandra E. Nix

2018-05-01

Full Text Available Elevated levels of silver in the environment are anticipated with an increase in silver nanoparticle (AgNP production and use in consumer products. To potentially reduce the burden of silver ion release from conventional solid core AgNPs, a lignin-core particle doped with silver ions and surface-stabilized with a polycationic electrolyte layer was engineered. Our objective was to determine whether any of the formulation components elicit toxicological responses using embryonic zebrafish. Ionic silver and free surface stabilizer were the most toxic constituents, although when associated separately or together with the lignin core particles, the toxicity of the formulations decreased significantly. The overall toxicity of lignin formulations containing silver was similar to other studies on a silver mass basis, and led to a significantly higher prevalence of uninflated swim bladder and yolk sac edema. Comparative analysis of dialyzed samples which had leached their loosely bound Ag+, showed a significant increase in mortality immediately after dialysis, in addition to eliciting significant increases in types of sublethal responses relative to the freshly prepared non-dialyzed samples. ICP-OES/MS analysis indicated that silver ion release from the particle into solution was continuous, and the rate of release differed when the surface stabilizer was not present. Overall, our study indicates that the lignin core is an effective alternative to conventional solid core AgNPs for potentially reducing the burden of silver released into the environment from a variety of consumer products.

Drug product selection: legal issues.

Science.gov (United States)

Christensen, T P; Kirking, D M; Ascione, F J; Welage, L S; Gaither, C A

2001-01-01

To review the potential legal liability of the pharmacist in the drug product selection process. Published articles identified through MEDLINE, published law reviews identified through InfoTrac, and appellate court decisions. Search terms used included pharmacist liability, drug product selection, and generic substitution. Additional articles, books, and appellate court decisions were identified from the bibliographies of retrieved articles and citations in appellate court decisions. Pharmacists engaging in drug product selection are civilly liable under three legal theories: negligence, express or implied warranties, and strict product liability. Potential criminal liability includes prosecution for insurance fraud, deceptive business practices, and violation of state drug product selection laws and regulation. Pharmacists increase their liability when engaging in drug product selection, but the increase is small. Still, the law continues to evolve as pharmacists seek expanded roles and responsibilities. When courts give closer examination to pharmacists' expanded role, it is likely that pharmacists' liability will increase.

Effect of preconditioning on silver leaching and bromide removal properties of silver-impregnated activated carbon (SIAC).

Science.gov (United States)

Rajaeian, Babak; Allard, Sébastien; Joll, Cynthia; Heitz, Anna

2018-07-01

Silver impregnated activated carbon (SIAC) has been found to be effective in mitigating the formation of brominated-disinfection by products during drinking water treatment. However, there are still uncertainties regarding its silver leaching properties, and strategies for the prevention of silver leaching have remained elusive. This study focused on the evaluation of one type of commercially available SIAC for its ability to remove bromide while minimising silver leaching from the material. Both synthetic and real water matrices were tested. Depending on solution pH, it was found that changing the surface charge properties of SIAC, as measured by the point of zero charge pH, can result in additional bromide removal while minimising the extent of silver leaching. To better understand the mechanism of silver leaching from the SIAC, eight preconditioning environments, i.e. variable pH and ionic strength were tested for a fixed amount of SIAC and two preconditioning environments were selected for a more detailed investigation. Experiments carried out in synthetic water showed that preconditioning at pH 10.4 did not deteriorate the capacity of SIAC to remove bromide, but significantly decreased the release of silver in the form of ionic silver (Ag + ), silver bromide (AgBr) and silver chloride (AgCl) from 40% for the pristine to 3% for the treated SIAC. This was confirmed using a groundwater sample. These results suggest that preconditioned SIAC has the potential to be an effective method for bromide removal with minimised silver leaching in a long-term field application for drinking water production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Antimicrobial activity of thin metallic silver flakes, waste products of a manufacturing process.

Science.gov (United States)

Anzano, Manuela; Tosti, Alessandra; Lasagni, Marina; Campiglio, Alfredo; Pitea, Demetrio; Collina, Elena

2011-01-01

The aim of the research was to develop new products and processes from a manufacturing waste from an Italian metallurgic company. The company produced thin silver metallic films and the production scraps were silver flakes. The possibility to use the silver flakes in water disinfection processes was studied. The antimicrobial activity of the flakes was investigated in batch using Escherichia coli as Gram-negative microorganism model. The flakes did not show any antimicrobial activity, so they were activated with two different processes: thermal activation in reducing atmosphere and chemical activation, obtaining, respectively, reduced flakes (RF) and chemical flakes (CF). The flakes, activated with either treatment, showed antimicrobial activity against E. coli. The kill rate was dependent on the type of activated flakes. The chemical flakes were more efficient than reduced flakes. The kill rate determined for 1 g of CF, 1.0 +/- 0.2 min(-1), was greater than the kill rate determined for 1 g of RF, 0.069 +/- 0.004 min(-1). This was confirmed also by the minimum inhibitory concentration values. It was demonstrated that the antimicrobial capability was dependent on flakes amount and on the type of aqueous medium. Furthermore, the flakes maintained their properties also when used a second time. Finally, the antimicrobial activities of flakes were tested in an effluent of a wastewater treatment plant where a variety of heterotrophic bacteria were present.

Silver nasal sprays: misleading Internet marketing.

Science.gov (United States)

Gaslin, Michael T; Rubin, Cory; Pribitkin, Edmund A

2008-04-01

Long-term use of silver-containing products is associated with a permanent bluish-gray discoloration of the skin known as argyria, but they remain widely available despite several measures by the FDA to regulate them. Several recent case reports have described the occurrence of argyria as a result of using these "natural" products. We used the five most common Internet search engines to find Web sites providing information on silver-containing nasal sprays. Of 49 Web sites analyzed, only 2 (4%) mentioned argyria as a possible complication, although 30 (61%) did caution against long-term use. Eight sites (16%) made specific claims about the health benefits of the product. All 49 sites (100%) provided direct or indirect links to buy silver-containing nasal sprays. We conclude that information about silver-containing nasal sprays on the Internet is misleading and inaccurate. Therefore, otolaryngologists should be aware of the misinformation their patients may be receiving about these products.

Gravimetric and volumetric determination of the purity of electrolytically refined silver and the produced silver nitrate

Directory of Open Access Journals (Sweden)

Ačanski Marijana M.

2007-01-01

Full Text Available Silver is, along with gold and the platinum-group metals, one of the so called precious metals. Because of its comparative scarcity, brilliant white color, malleability and resistance to atmospheric oxidation, silver has been used in the manufacture of coins and jewelry for a long time. Silver has the highest known electrical and thermal conductivity of all metals and is used in fabricating printed electrical circuits, and also as a coating for electronic conductors. It is also alloyed with other elements such as nickel or palladium for use in electrical contacts. The most useful silver salt is silver nitrate, a caustic chemical reagent, significant as an antiseptic and as a reagent in analytical chemistry. Pure silver nitrate is an intermediate in the industrial preparation of other silver salts, including the colloidal silver compounds used in medicine and the silver halides incorporated into photographic emulsions. Silver halides become increasingly insoluble in the series: AgCl, AgBr, AgI. All silver salts are sensitive to light and are used in photographic coatings on film and paper. The ZORKA-PHARMA company (Sabac, Serbia specializes in the production of pharmaceutical remedies and lab chemicals. One of its products is chemical silver nitrate (argentum-nitricum (l. Silver nitrate is generally produced by dissolving pure electrolytically refined silver in hot 48% nitric acid. Since the purity of silver nitrate, produced in 2002, was not in compliance with the p.a. level of purity, there was doubt that the electrolytically refined silver was pure. The aim of this research was the gravimetric and volumetric determination of the purity of electrolytically refined silver and silver nitrate, produced industrially and in a laboratory. The purity determination was carried out gravimetrically, by the sedimentation of silver(I ions in the form of insoluble silver salts: AgCl, AgBr and Agi, and volumetrically, according to Mohr and Volhardt. The

Characterization of silver nanoparticles in selected consumer products and its relevance for predicting children's potential exposures

Science.gov (United States)

Due to their antifungal, antibacterial, antiviral, and antimicrobial properties, silver nanoparticles (AgNPs) are used in consumer products intended for use by children or in the home. Children may be especially affected by the normal use of consumer products because of their phy...

Prescription Drugs, Over-the-Counter Drugs, Supplements and Herbal Products

Science.gov (United States)

... at risk? Zika virus and pregnancy Folic acid Medicine safety and pregnancy Birth defects prevention Learn how ... the-counter drugs, supplements and herbal products Prescription drugs, over-the-counter drugs, supplements and herbal products ...

Silver nanoparticle production by Rhizopus stolonifer and its antibacterial activity against extended spectrum β-lactamase producing (ESBL) strains of Enterobacteriaceae

International Nuclear Information System (INIS)

Banu, Afreen; Rathod, Vandana; Ranganath, E.

2011-01-01

Highlights: → Silver nanoparticle production by using Rhizopus stolonifer. → Antibacterial activity of silver nanoparticles against extended spectrum β-lactamase producing (ESBL) strains of Enterobacteriaceae. → Synergistic effect of antibiotics with silver nanoparticles towards ESBL-strains. → Characterization of silver nanoparticles made by UV-vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, atomic force microscopy (AFM). -- Abstract: This report focuses on the synthesis of silver nanoparticles using the fungus, Rhizopus stolonifer and its antimicrobial activity. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Characterization of newly synthesized silver nanoparticles was made by UV-visible absorption spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and atomic force microscope (AFM). TEM micrograph revealed the formation of spherical nanoparticles with size ranging between 3 and 20 nm. The biosynthesized silver nanoparticles (AgNPs) showed excellent antibacterial activity against ESBL-strains which includes E. coli, Proteus. sp. and Klebsiella sp.

Silver nanoparticle production by Rhizopus stolonifer and its antibacterial activity against extended spectrum {beta}-lactamase producing (ESBL) strains of Enterobacteriaceae

Energy Technology Data Exchange (ETDEWEB)

Banu, Afreen [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India); Rathod, Vandana, E-mail: drvandanarathod@rediffmail.com [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India); Ranganath, E. [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India)

2011-09-15

Highlights: {yields} Silver nanoparticle production by using Rhizopus stolonifer. {yields} Antibacterial activity of silver nanoparticles against extended spectrum {beta}-lactamase producing (ESBL) strains of Enterobacteriaceae. {yields} Synergistic effect of antibiotics with silver nanoparticles towards ESBL-strains. {yields} Characterization of silver nanoparticles made by UV-vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, atomic force microscopy (AFM). -- Abstract: This report focuses on the synthesis of silver nanoparticles using the fungus, Rhizopus stolonifer and its antimicrobial activity. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Characterization of newly synthesized silver nanoparticles was made by UV-visible absorption spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and atomic force microscope (AFM). TEM micrograph revealed the formation of spherical nanoparticles with size ranging between 3 and 20 nm. The biosynthesized silver nanoparticles (AgNPs) showed excellent antibacterial activity against ESBL-strains which includes E. coli, Proteus. sp. and Klebsiella sp.

Toxicogenomic responses of nanotoxicity in Daphnia magna exposed to silver nitrate and coated silver nanoparticles

Science.gov (United States)

Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxic...

Silver Entrepreneurship Agenda in Malaysia: A Proposed Model for Productive Aging

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Aizzat Mohd Nasurdin

2012-03-01

Full Text Available This paper aims at proposing a framework for productive aging among those aged 45-plus or retiree via entrepreneurial initiatives, known as ‘silver entrepreneurs’. Evidence has shown that the number of Malaysians aged population is estimated to be more than 1.4 million and is projected to increase to 3.3 million in the year 2020 (Mafauzy, 2000. It is acknowledged that a group of these will comprise of professionals who are aged 45-plus and retirees with relevant industry experience as well as knowledge and well-established networks built up over their working careers which will enable them to effectively identify entrepreneurial opportunities and secure resources efficiently to exploit them. However, there is little research on and understanding of what drives these ‘silver entrepreneurs’, with most of the research, focussed on entrepreneurial ventures started by 18-35 year-olds.  This means that policy-makers are ill-equipped to develop specific measures that will assist retirees into a second or sunset career in entrepreneurship.  This research aims to bridge the gap by assessing the profile and motivations of silver entrepreneurs in Malaysia with a specific focus on understanding the internal and external factors that affect their intentions to start new ventures as well as factors that affect the success and growth of these ventures. 

Colloidal silver nanoparticles improve anti-leukemic drug efficacy via amplification of oxidative stress.

Science.gov (United States)

Guo, Dawei; Zhang, Junren; Huang, Zhihai; Jiang, Shanxiang; Gu, Ning

2015-02-01

Recently, increased reactive oxygen species (ROS) levels and altered redox status in cancer cells have become a novel therapeutic strategy to improve cancer selectivity over normal cells. It has been known that silver nanoparticles (AgNPs) display anti-leukemic activity via ROS overproduction. Hence, we hypothesized that AgNPs could improve therapeutic efficacy of ROS-generating agents against leukemia cells. In the current study, N-(4-hydroxyphenyl)retinamide (4-HPR), a synthetic retinoid, was used as a drug model of ROS induction to investigate its synergistic effect with AgNPs. The data exhibited that AgNPs with uniform size prepared by an electrochemical method could localize in the lysosomes, mitochondria and cytoplasm of SHI-1 cells. More importantly, AgNPs together with 4-HPR could exhibit more cytotoxicity and apoptosis via overproduction of ROS in comparison with that alone. Taken together, these results reveal that AgNPs combined with ROS-generating drugs could potentially enhance therapeutic efficacy against leukemia cells, thereby providing a novel strategy for AgNPs in leukemia therapy. Copyright © 2015. Published by Elsevier B.V.

Evaluation of dose dependent antimicrobial activity of self-assembled chitosan, nano silver and chitosan-nano silver composite against several pathogens.

Science.gov (United States)

Tareq, Foysal Kabir; Fayzunnesa, Mst; Kabir, Md Shahariar; Nuzat, Musrat

2018-01-01

The aim of this investigation to preparation of silver nanoparticles organized chitosan nano polymer, which effective against microbial and pathogens, when apply to liquid medium and edible food products surface, will rescue the growth of microbes. Self-assembly approach used to synthesis of silver nanoparticles and silver nanoparticles organized chitosan nano polymer. Silver nanoparticles and silver nanoparticles organized chitosan nano polymer and film characterized using Ultra-violate visible spectrometer (UV-vis), X-ray diffraction (X-ray), and Scanning electronic microscope (SEM). The crystalline structured protein capped nano silver successfully synthesized at range of 12 nm-29 nm and organized into chitosan nano polymer. Antimicrobial ingredient in liquid medium and food product surface provide to rescue oxidative change and growth of microorganism to provide higher safety. The silver nanoparticles organized chitosan nano polymer caused the death of microorganism. The materials in nano scale synthesized successfully using self-assembly method, which showed good antimicrobial properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photostability and Photostabilization of Drugs and Drug Products

OpenAIRE

Ahmad, Iqbal; Ahmed, Sofia; Anwar, Zubair; Sheraz, Muhammad Ali; Sikorski, Marek

2016-01-01

Photostability studies of drugs and drug products are an integral part of the product development process in the pharmaceutical industry. These studies are carried out to ensure quality, efficacy, and safety of the formulated products during manufacture, storage, and use. This review deals with the concept of photostability and related aspects and the literature available in the field. It highlights the role of the photochemistry in the photostability studies, describes the functional groups ...

Silver Nanoparticles as Potential Antibacterial Agents

Directory of Open Access Journals (Sweden)

Gianluigi Franci

2015-05-01

Full Text Available Multi-drug resistance is a growing problem in the treatment of infectious diseases and the widespread use of broad-spectrum antibiotics has produced antibiotic resistance for many human bacterial pathogens. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs, but unfortunately infectious diseases continue to be a major health burden worldwide. Since ancient times, silver was known for its anti-bacterial effects and for centuries it has been used for prevention and control of disparate infections. Currently nanotechnology and nanomaterials are fully integrated in common applications and objects that we use every day. In addition, the silver nanoparticles are attracting much interest because of their potent antibacterial activity. Many studies have also shown an important activity of silver nanoparticles against bacterial biofilms. This review aims to summarize the emerging efforts to address current challenges and solutions in the treatment of infectious diseases, particularly the use of nanosilver antimicrobials.

Silver nanoparticles as potential antibacterial agents.

Science.gov (United States)

Franci, Gianluigi; Falanga, Annarita; Galdiero, Stefania; Palomba, Luciana; Rai, Mahendra; Morelli, Giancarlo; Galdiero, Massimiliano

2015-05-18

Multi-drug resistance is a growing problem in the treatment of infectious diseases and the widespread use of broad-spectrum antibiotics has produced antibiotic resistance for many human bacterial pathogens. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs, but unfortunately infectious diseases continue to be a major health burden worldwide. Since ancient times, silver was known for its anti-bacterial effects and for centuries it has been used for prevention and control of disparate infections. Currently nanotechnology and nanomaterials are fully integrated in common applications and objects that we use every day. In addition, the silver nanoparticles are attracting much interest because of their potent antibacterial activity. Many studies have also shown an important activity of silver nanoparticles against bacterial biofilms. This review aims to summarize the emerging efforts to address current challenges and solutions in the treatment of infectious diseases, particularly the use of nanosilver antimicrobials.

Fission products silver, palladium, and cadmium identification in neutron-irradiated SiC TRISO particles using a Cs-Corrected HRTEM

Energy Technology Data Exchange (ETDEWEB)

Rooyen, I.J. van, E-mail: isabella.vanrooyen@inl.gov [Fuel Design and Development Department, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID, 83415-6188 (United States); Olivier, E.J.; Neethling, J.H. [Centre for High Resolution Electron Microscopy, Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

2016-08-01

Electron microscopy investigations of selected coated particles from the first advanced gas reactor experiment at Idaho National Laboratory provided important information on fission product distribution and chemical composition in the silicon-carbide (SiC) layer. Silver precipitates were nano-sized, and therefore high-resolution transmission electron microscopy (HRTEM) was used to provide more information at the atomic level. Based on gamma-ray analysis, this particle which was irradiated to an average burnup of 19.38% fissions per initial metal atom, may have released as much as 10% of its available Ag-110 m inventory during irradiation. The HRTEM investigation focused on silver, palladium, and cadmium due to interest in silver transport mechanisms and possible correlation with palladium and silver previously found. Palladium, silver, and cadmium were found to co-exist in some of the SiC grain boundaries and triple junctions. This study confirmed palladium both at inter and intragranular sites. Phosphor was identified in SiC grain boundaries and triple points. - Highlights: • First high resolution electron microscopy fission product nano-structural locations of irradiated TRISO coated particles. • Pd observed inside SiC grains in proximity to planar defects e.g. stacking faults. • Ag co-exists with Pd and Cd only may suggest a Pd-assisted transport mechanism. • First finding of neutron transmutation product P, in SiC layer of TRISO coated particles. No direct link to Ag transport. • No significant Pd corrosion of SiC observed even at this high resolution images.

Biosynthesis, characterization, and antimicrobial applications of silver nanoparticles.

Science.gov (United States)

Singh, Priyanka; Kim, Yeon Ju; Singh, Hina; Wang, Chao; Hwang, Kyu Hyon; Farh, Mohamed El-Agamy; Yang, Deok Chun

2015-01-01

In the present study, the strain Brevibacterium frigoritolerans DC2 was explored for the efficient and extracellular synthesis of silver nanoparticles. These biosynthesized silver nanoparticles were characterized by ultraviolet-visible spectrophotometry, which detected the formation of silver nanoparticles in the reaction mixture and showed a maximum absorbance at 420 nm. In addition, field emission transmission electron microscopy revealed the spherical shape of the nanoparticles. The dynamic light scattering results indicated the average particle size of the product was 97 nm with a 0.191 polydispersity index. Furthermore, the product was analyzed by energy dispersive X-ray spectroscopy, X-ray diffraction, and elemental mapping, which displayed the presence of elemental silver in the product. Moreover, on a medical platform, the product was checked against pathogenic microorganisms including Vibrio parahaemolyticus, Salmonella enterica, Bacillus anthracis, Bacillus cereus, Escherichia coli, and Candida albicans. The nanoparticles demonstrated antimicrobial activity against all of these pathogenic microorganisms. Additionally, the silver nanoparticles were evaluated for their combined effects with the commercial antibiotics lincomycin, oleandomycin, vancomycin, novobiocin, penicillin G, and rifampicin against these pathogenic microorganisms. These results indicated that the combination of antibiotics with biosynthesized silver nanoparticles enhanced the antimicrobial effects of antibiotics. Therefore, the current study is a demonstration of an efficient biological synthesis of silver nanoparticles by B. frigoritolerans DC2 and its effect on the enhancement of the antimicrobial efficacy of well-known commercial antibiotics.

Green biosynthesis of silver nanoparticles using pomegranate peel and inhibitory effects of the nanoparticles on aflatoxin production

International Nuclear Information System (INIS)

Monira, A.O.; Mohammad, M.A.; Ashraf, H.A.

2017-01-01

In this work, pomegranate peel has been used as a natural and safe method for biosynthesis of silver nanoparticles. The synthesis of silver nanoparticles was confirmed using UV spectroscopy, which showed a peak around a wavelength of 437 nm. The morphology showed spherical and monodispersed nanoparticles with a size range between 5-50 nm. Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD) experiments revealed their crystalline nature. Active functional groups in the synthesized silver nanoparticles were determined using Fourier transform infrared (FTIR) spectrometers contained four bands at 3281.21 cm/sup -1/, possibly indicating the participationof O-H functional group. The peak take place at 1,636.22 cm/sup -1/ may be pointed to C = N bending in the amide group or C = O stretching in carboxyl. Transfer in this peak (from 1,641 to 1,643 cm/sup -1/) shown the possible role of amino groups or carboxyl in nanoparticle synthesis. The peaks at 431.95 and 421.28 cm/sup -1/ be related to AgNPs bonding with oxygen from hydroxyl groups which confirm the role of pomegranate peel as a reducing agent. Furthermore, we investigated effects of these nanoparticles on aflatoxin B1 production by the fungus Aspergillus flavus, isolated from hazelnut. The results found that aflatoxin production in all A. flavus isolates decreased with an increase in the concentration of silver nanoparticles. Maximum suppression of aflatoxin production was recorded at a nanoparticle concentration of 150 ppm. (author)

RESEARCH REGARDING DIFFERENT APPLICATIONS OF SILVER IN TEXTILE

Directory of Open Access Journals (Sweden)

PRALEA Jeni

2014-05-01

Full Text Available Experimental research presented in this paper are based on septic properties of silver. The experiment creates premises for developing of project concepts, products and inscriptions (applications of graphic signs, ionization treatments with silver ions, which ensures the quality of the septic product in an ecological way (no preservatives and no toxic chemicals, characterized by a modern design. Thus developing concepts of textile products, the development of accessories needed for manufacturing textile products that ensure the property of being septic, development of eco-friendly products without thermochemical treatments, are applications that the designer can achieve based on the properties of silver. The paper presents both technological capabilities and properties of silver to be able to be used in the field of textiles, as well as the creativity of designers to generate ideas for new applications of this material in the field of industrial products in the textile, garments. The importance of the designer's involvement in creating septic and ecological products, which respects the environment represent the focus of this work. The deformability properties of silver are the inspiration for designer even when it shows major deformities, caused as a result of tests of endurance. Surface modifications of this material can cause identification of applications of this precious metal, turning in esthetic product, scrap, samples, test specimens subjected to various tests

Mass production compatible fabrication techniques of single-crystalline silver metamaterials and plasmonics devices

Science.gov (United States)

Rodionov, Ilya A.; Baburin, Alexander S.; Zverev, Alexander V.; Philippov, Ivan A.; Gabidulin, Aidar R.; Dobronosova, Alina A.; Ryzhova, Elena V.; Vinogradov, Alexey P.; Ivanov, Anton I.; Maklakov, Sergey S.; Baryshev, Alexander V.; Trofimov, Igor V.; Merzlikin, Alexander M.; Orlikovsky, Nikolay A.; Rizhikov, Ilya A.

2017-08-01

During last 20 years, great results in metamaterials and plasmonic nanostructures fabrication were obtained. However, large ohmic losses in metals and mass production compatibility still represent the most serious challenge that obstruct progress in the fields of metamaterials and plasmonics. Many recent research are primarily focused on developing low-loss alternative materials, such as nitrides, II-VI semiconductor oxides, high-doped semiconductors, or two-dimensional materials. In this work, we demonstrate that our perfectly fabricated silver films can be an effective low-loss material system, as theoretically well-known. We present a fabrication technology of plasmonic and metamaterial nanodevices on transparent (quartz, mica) and non-transparent (silicon) substrates by means of e-beam lithography and ICP dry etch instead of a commonly-used focused ion beam (FIB) technology. We eliminate negative influence of litho-etch steps on silver films quality and fabricate square millimeter area devices with different topologies and perfect sub-100 nm dimensions reproducibility. Our silver non-damage fabrication scheme is tested on trial manufacture of spasers, plasmonic sensors and waveguides, metasurfaces, etc. These results can be used as a flexible device manufacture platform for a broad range of practical applications in optoelectronics, communications, photovoltaics and biotechnology.

Effect of silver nanoparticles on concentration of silver heavy element and growth indexes in cucumber (Cucumis sativus L. negeen)

International Nuclear Information System (INIS)

Shams, Gholamabbas; Ranjbar, Morteza; Amiri, Aliasghar

2013-01-01

The tremendous progress on nanoparticle research area has been made significant effects on the economy, society, and the environment. Silver nanoparticle is one of the most important particles in these categories. Silver nanoparticles can be converted to the heavy silver metal in water by oxidation. Moreover, in the high amounts of silver concentration, they will be accumulated in different parts of the plant. However, by changing the morphology of the plant, the production will be harmful for human consumptions. In this study, nano-powders with average 50 nm silver particles are mixed with deionized distilled water in a completely randomized design. Seven treatments with various concentrations of suspension silver nanoparticles were prepared and repeated in four different parts of the plant in a regular program of spraying. Samples were analyzed to study the growth indexes and concentration of silver in different parts of the plant. It was observed that with increasing concentration of silver nanoparticles on cucumber, the growth indexes (except pH fruit), and the concentration of silver heavy metal are increased significantly. The incremental concentration had the linear relationship with correlation coefficient 0.95 and an average of 0.617 PPM by increasing of each unit in one thousand concentration of nanosilver. Although, by increasing concentration of silver nanoparticles as spraying form, the plant morphological characteristics were improved, the concentration of silver heavy metal in various plant organs was increased. These results open a new pathway to consider the effect of nanoparticles on plant’s productions for human consumptions.

Effect of silver nanoparticles on concentration of silver heavy element and growth indexes in cucumber (Cucumis sativus L. negeen)

Energy Technology Data Exchange (ETDEWEB)

Shams, Gholamabbas, E-mail: ghs@iaushiraz.net; Ranjbar, Morteza [Shiraz Branch, Islamic Azad University, Department of Physics (Iran, Islamic Republic of); Amiri, Aliasghar [Shiraz Branch, Islamic Azad University, Department of Chemistry (Iran, Islamic Republic of)

2013-05-15

The tremendous progress on nanoparticle research area has been made significant effects on the economy, society, and the environment. Silver nanoparticle is one of the most important particles in these categories. Silver nanoparticles can be converted to the heavy silver metal in water by oxidation. Moreover, in the high amounts of silver concentration, they will be accumulated in different parts of the plant. However, by changing the morphology of the plant, the production will be harmful for human consumptions. In this study, nano-powders with average 50 nm silver particles are mixed with deionized distilled water in a completely randomized design. Seven treatments with various concentrations of suspension silver nanoparticles were prepared and repeated in four different parts of the plant in a regular program of spraying. Samples were analyzed to study the growth indexes and concentration of silver in different parts of the plant. It was observed that with increasing concentration of silver nanoparticles on cucumber, the growth indexes (except pH fruit), and the concentration of silver heavy metal are increased significantly. The incremental concentration had the linear relationship with correlation coefficient 0.95 and an average of 0.617 PPM by increasing of each unit in one thousand concentration of nanosilver. Although, by increasing concentration of silver nanoparticles as spraying form, the plant morphological characteristics were improved, the concentration of silver heavy metal in various plant organs was increased. These results open a new pathway to consider the effect of nanoparticles on plant's productions for human consumptions.

Major activated corrosion products cobalt, silver and antimony in the primary coolant of PWR power plants

International Nuclear Information System (INIS)

Xu Mingxia

2012-01-01

The production of the major activated corrosion products such as cobalt, silver and antimony in the primary coolant of PWR power plants and the impacts on the increase of the dose rates caused by these corrosion products during the shutdown are described in the paper. Investigating the corrosion product behavior during the operation and shutdown periods aims at detecting the appearance of these radiological pollutants in the early time and searching relevant solutions that may enable eventually to decrease the dose rate. The solutions may include: Replacing critical material in the primary system's equipment and components, which contact with primary coolant circuit to possibly limit the source term, Elaborating strictly the specific chemical and shutdown procedure to optimize the purification capacity and to minimize the over-contaminations; Improving purification techniques according to the real operation circumstance, and limiting the impacts of these pollutants. It is obvious in the real practices that implementing appropriate solution will be benefit to decrease or limit the pollutants species like cobalt, silver and antimony. (author)

Spectrum of antimicrobial activity associated with ionic colloidal silver.

Science.gov (United States)

Morrill, Kira; May, Kathleen; Leek, Daniel; Langland, Nicole; Jeane, La Deana; Ventura, Jose; Skubisz, Corey; Scherer, Sean; Lopez, Eric; Crocker, Ephraim; Peters, Rachel; Oertle, John; Nguyen, Krystine; Just, Scott; Orian, Michael; Humphrey, Meaghan; Payne, David; Jacobs, Bertram; Waters, Robert; Langland, Jeffrey

2013-03-01

Silver has historically and extensively been used as a broad-spectrum antimicrobial agent. However, the Food and Drug Administration currently does not recognize colloidal silver as a safe and effective antimicrobial agent. The goal of this study was to further evaluate the antimicrobial efficacy of colloidal silver. Several strains of bacteria, fungi, and viruses were grown under multicycle growth conditions in the presence or absence of ionic colloidal silver in order to assess the antimicrobial activity. For bacteria grown under aerobic or anaerobic conditions, significant growth inhibition was observed, although multiple treatments were typically required. For fungal cultures, the effects of ionic colloidal silver varied significantly between different genera. No viral growth inhibition was observed with any strains tested. The study data support ionic colloidal silver as a broad-spectrum antimicrobial agent against aerobic and anaerobic bacteria, while having a more limited and specific spectrum of activity against fungi.

Raman scattering of Cisplatin near silver nanoparticles

Science.gov (United States)

Mirsaleh-Kohan, Nasrin; Duplanty, Michael; Torres, Marjorie; Moazzezi, Mojtaba; Rostovtsev, Yuri V.

2018-03-01

The Raman scattering of Cisplatin (the first generation of anticancer drugs) has been studied. In the presence of silver nanoparticles, strong modifications of Raman spectra have been observed. The Raman frequencies have been shifted and the line profiles are broadened. We develop a theoretical model to explain the observed features of the Raman scattering. The model takes into account self-consistently the interaction of molecules with surface plasmonic waves excited in the silver nanoparticles, and it provides a qualitative agreement with the observed Raman spectra. We have demonstrated that the using silver nanoparticles can increase sensitivity of the technique, and potentially it has a broader range of applications to both spectroscopy and microscopy.

Characterization of Electrochemically Generated Silver

Science.gov (United States)

Adam, Niklas; Martinez, James; Carrier, Chris

2014-01-01

Silver biocide offers a potential advantage over iodine, the current state of the art in US spacecraft disinfection technology, in that silver can be safely consumed by the crew. Low concentrations of silver (Silver does not require hardware to remove it from a water system, and therefore can provide a simpler means for disinfecting water. The Russian segment of the International Space Station has utilized an electrochemically generated silver solution, which is colloidal in nature. To be able to reliably provide a silver biocide to drinking water by electrochemical means would reduce mass required for removing another biocide such as iodine from the water. This would also aid in crew time required to replace iodine removal cartridges. Future long term missions would benefit from electrochemically produced silver as the biocide could be produced on demand and requires only a small concentration to be effective. Since it can also be consumed safely, there is less mass in removal hardware and little consumables required for production. The goal of this project initially is to understand the nature of the electrochemically produced silver, the particle sizes produced by the electrochemical cell and the effect that voltage adjustment has on the particle size. In literature, it has been documented that dissolved oxygen and pH have an effect on the ionization of the electrochemical silver so those parameters would be measured and possibly adjusted to understand their effect on the silver.

Selective recovery of silver from waste low-temperature co-fired ceramic and valorization through silver nanoparticle synthesis.

Science.gov (United States)

Swain, Basudev; Shin, Dongyoon; Joo, So Yeong; Ahn, Nak Kyoon; Lee, Chan Gi; Yoon, Jin-Ho

2017-11-01

Considering the value of silver metal and silver nanoparticles, the waste generated during manufacturing of low temperature co-fired ceramic (LTCC) were recycled through the simple yet cost effective process by chemical-metallurgy. Followed by leaching optimization, silver was selectively recovered through precipitation. The precipitated silver chloride was valorized though silver nanoparticle synthesis by a simple one-pot greener synthesis route. Through leaching-precipitation optimization, quantitative selective recovery of silver chloride was achieved, followed by homogeneous pure silver nanoparticle about 100nm size were synthesized. The reported recycling process is a simple process, versatile, easy to implement, requires minimum facilities and no specialty chemicals, through which semiconductor manufacturing industry can treat the waste generated during manufacturing of LTCC and reutilize the valorized silver nanoparticles in manufacturing in a close loop process. Our reported process can address issues like; (i) waste disposal, as well as value-added silver recovery, (ii) brings back the material to production stream and address the circular economy, and (iii) can be part of lower the futuristic carbon economy and cradle-to-cradle technology management, simultaneously. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development Considerations for Nanocrystal Drug Products.

Science.gov (United States)

Chen, Mei-Ling; John, Mathew; Lee, Sau L; Tyner, Katherine M

2017-05-01

Nanocrystal technology has emerged as a valuable tool for facilitating the delivery of poorly water-soluble active pharmaceutical ingredients (APIs) and enhancing API bioavailability. To date, the US Food and Drug Administration (FDA) has received over 80 applications for drug products containing nanocrystals. These products can be delivered by different routes of administration and are used in a variety of therapeutic areas. To aid in identifying key developmental considerations for these products, a retrospective analysis was performed on the submissions received by the FDA to date. Over 60% of the submissions were for the oral route of administration. Based on the Biopharmaceutics Classification System (BCS), most nanocrystal drugs submitted to the FDA are class II compounds that possess low aqueous solubility and high intestinal permeability. Impact of food on drug bioavailability was reduced for most nanocrystal formulations as compared with their micronized counterparts. For all routes of administration, dose proportionality was observed for some, but not all, nanocrystal products. Particular emphasis in the development of nanocrystal products was placed on the in-process tests and controls at critical manufacturing steps (such as milling process), mitigation and control of process-related impurities, and the stability of APIs or polymorphic form (s) during manufacturing and upon storage. This emphasis resulted in identifying challenges to the development of these products including accurate determination of particle size (distribution) of drug substance and/or nanocrystal colloidal dispersion, identification of polymorphic form (s), and establishment of drug substance/product specifications.

Synthesis of positively charged hybrid PHMB-stabilized silver nanoparticles: the search for a new type of active substances used in plant protection products

Science.gov (United States)

Krutyakov, Yurii A.; Kudrinsky, Alexey A.; Gusev, Alexander A.; Zakharova, Olga V.; Klimov, Alexey I.; Yapryntsev, Alexey D.; Zherebin, Pavel M.; Shapoval, Olga A.; Lisichkin, Georgii V.

2017-07-01

Modern agriculture calls for a decrease in pesticide application, particularly in order to decrease the negative impact on the environment. Therefore the development of new active substances and plant protection products (PPP) to minimize the chemical load on ecosystems is a very important problem. Substances based on silver nanoparticles are a promising solution of this problem because of the fact that in correct doses such products significantly increase yields and decrease crop diseases while displaying low toxicity to humans and animals. In this paper we for the first time propose application of polymeric guanidine compounds with varying chain lengths (from 10 to 130 elementary links) for the design and synthesis of modified silver nanoparticles to be used as the basis of a new generation of PPP. Colloidal solutions of nanocrystalline silver containing 0.5 g l-1 of silver and 0.01-0.4 g l-1 of polyhexamethylene biguanide hydrochloride (PHMB) were obtained by reduction of silver nitrate with sodium borohydride in the presence of PHMB. The field experiment has shown that silver-containing solutions have a positive effect on agronomic properties of potato, wheat and apple. Also the increase in activity of such antioxidant system enzymes as peroxidase and catalase in the tissues of plants treated with nanosilver has been registered.

Continuous synthesis of colloidal silver nanoparticles by electrochemical discharge in aqueous solutions

International Nuclear Information System (INIS)

Tseng, Kuo-Hsiung; Chen, Yu-Chun; Shyue, Jing-Jong

2011-01-01

This article presents an electrochemical discharge (ECD) method that consists of a combination of chemical methods and electric arc discharges. In the method, 140 V is applied to an Ag electrode from a DC power supply. The arc-discharge between the electrodes produces metallic silver nanoparticles and silver ions in the aqueous solution. Compared with the original arc discharge, this ECD method creates smaller nanoparticles, prevents clumping of the nanoparticles, and shortens the production time. The citrate ions also reduce the silver ions to silver nanoparticles. In addition, the citrate ions cap the surface of the produced silver nanoparticles and the zeta potential increases. In this article, the weight loss of the electrodes and the reduction of silver ions to silver nanoparticles as a function of citrate concentration and electric conductivity of the medium are discussed. Furthermore, the properties of the colloidal silver prepared with ECD are analyzed by UV–Vis spectroscopy, dynamic light scattering, electrophoresis light scattering, and scanning electron microscopy. Finally, a continuous production apparatus is presented for the continuous production of colloidal silver.

Effects of silver nitrate and silver nanoparticles on a planktonic community: general trends after short-term exposure.

Directory of Open Access Journals (Sweden)

Jens Boenigk

Full Text Available Among metal pollutants silver ions are one of the most toxic forms, and have thus been assigned to the highest toxicity class. Its toxicity to a wide range of microorganisms combined with its low toxicity to humans lead to the development of a wealth of silver-based products in many bactericidal applications accounting to more than 1000 nano-technology-based consumer products. Accordingly, silver is a widely distributed metal in the environment originating from its different forms of application as metal, salt and nanoparticle. A realistic assessment of silver nanoparticle toxicity in natural waters is, however, problematic and needs to be linked to experimental approaches. Here we apply metatranscriptome sequencing allowing for elucidating reactions of whole communities present in a water sample to stressors. We compared the toxicity of ionic silver and ligand-free silver nanoparticles by short term exposure on a natural community of aquatic microorganisms. We analyzed the effects of the treatments on metabolic pathways and species composition on the eukaryote metatranscriptome level in order to describe immediate molecular responses of organisms using a community approach. We found significant differences between the samples treated with 5 µg/L AgNO3 compared to the controls, but no significant differences in the samples treated with AgNP compared to the control samples. Statistical analysis yielded 126 genes (KO-IDs with significant differential expression with a false discovery rate (FDR <0.05 between the control (KO and AgNO3 (NO3 groups. A KEGG pathway enrichment analysis showed significant results with a FDR below 0.05 for pathways related to photosynthesis. Our study therefore supports the view that ionic silver rather than silver nanoparticles are responsible for silver toxicity. Nevertheless, our results highlight the strength of metatranscriptome approaches for assessing metal toxicity on aquatic communities.

Electronic Animal Drug Product Listing Directory

Data.gov (United States)

U.S. Department of Health & Human Services — The Electronic Animal Drug Product Listing Directory is a directory of all animal drug products that have been listed electronically since June 1, 2009, to comply...

Optimization of silver-dielectric-silver nanoshell for sensing applications

International Nuclear Information System (INIS)

Shirzaditabar, Farzad; Saliminasab, Maryam

2013-01-01

In this paper, resonance light scattering (RLS) properties of a silver-dielectric-silver nanoshell, based on quasi-static approach and plasmon hybridization theory, are investigated. Scattering spectrum of silver-dielectric-silver nanoshell has two intense and clearly separated RLS peaks and provides a potential for biosensing based on surface plasmon resonance and surface-enhanced Raman scattering. The two RLS peaks in silver-dielectric-silver nanoshell are optimized by tuning the geometrical dimensions. In addition, the optimal geometry is discussed to obtain the high sensitivity of silver-dielectric-silver nanoshell. As the silver core radius increases, the sensitivity of silver-dielectric-silver nanoshell decreases whereas increasing the middle dielectric thickness increases the sensitivity of silver-dielectric-silver nanoshell

Silver nanoparticles - Wolves in sheep's clothing?

DEFF Research Database (Denmark)

Foldbjerg, Rasmus Bruno; Jiang, Xiumei; Micləuş, Teodora

2015-01-01

Silver nanoparticles (Ag NPs) are one of the most widely utilized engineered nanomaterials (ENMs) in commercial products due to their effective antibacterial activity, high electrical conductivity, and optical properties. Therefore, they have been one of the most intensively investigated nanomate......Silver nanoparticles (Ag NPs) are one of the most widely utilized engineered nanomaterials (ENMs) in commercial products due to their effective antibacterial activity, high electrical conductivity, and optical properties. Therefore, they have been one of the most intensively investigated...

Facile synthesis of silver/silver thiocyanate (Ag@AgSCN plasmonic nanostructures with enhanced photocatalytic performance

Directory of Open Access Journals (Sweden)

Xinfu Zhao

2017-12-01

Full Text Available A nanostructured plasmonic photocatalyst, silver/silver thiocyanate (Ag@AgSCN, has been prepared by a simple precipitation method followed by UV-light-induced reduction. The ratio of Ag to silver thiocyanate (AgSCN can be controlled by simply adjusting the photo-induced reduction time. The formation mechanism of the product was investigated based on the time-dependent experiments. Further experiments indicated that the prepared Ag@AgSCN nanostructures with an atomic ratio of Ag/AgSCN = 0.0463 exhibited high photocatalytic activity and long-term stability for the degradation of oxytetracycline (84% under visible-light irradiation. In addition to the microstructure and high specific surface area, the enhanced photocatalytic activity was mainly caused by the surface plasmon resonance of Ag nanoparticles, and the high stability of AgSCN resulted in the long-term stability of the photocatalyst product.

Extracellular polysaccharide production by a novel osmotolerant marine strain of Alteromonas macleodii and its application towards biomineralization of silver.

Directory of Open Access Journals (Sweden)

Ananya Mehta

Full Text Available The present study demonstrates exopolysaccharide production by an osmotolerant marine isolate and also describes further application of the purified polysaccharide for production of colloidal suspension of silver nanoparticles with narrow size distribution. Phylogenetic analysis based on 16S r RNA gene sequencing revealed close affinity of the isolate to Alteromonas macleodii. Unlike earlier reports, where glucose was used as the carbon source, lactose was found to be the most suitable substrate for polysaccharide production. The strain was capable of producing 23.4 gl(-1 exopolysaccharide with a productivity of 7.8 gl(-1 day(-1 when 15% (w/v lactose was used as carbon source. Furthermore, the purified polysaccharide was able to produce spherical shaped silver nanoparticles of around 70 nm size as characterized by Uv-vis spectroscopy, Dynamic light scattering and Transmission electron microscopy. These observations suggested possible commercial potential of the isolated strain for production of a polysaccharide which has the capability of synthesizing biocompatible metal nanoparticle.

21 CFR 333.350 - Labeling of acne drug products.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Labeling of acne drug products. 333.350 Section... Acne Drug Products § 333.350 Labeling of acne drug products. (a) Statement of identity. The labeling of the product contains the established name of the drug, if any, and identifies the product as an “acne...

Effects of silver adsorbed on fumed silica, silver phosphate glass, bentonite organomodified with silver and titanium dioxide in aquatic indicator organisms.

Science.gov (United States)

Tomacheski, Daiane; Pittol, Michele; Simões, Douglas Naue; Ribeiro, Vanda Ferreira; Santana, Ruth Marlene Campomanes

2017-06-01

In order to reduce the level of transmission of diseases caused by bacteria and fungi, the development of antimicrobial additives for use in personal care, hygiene products, clothing and others has increased. Many of these additives are based on metals such as silver and titanium. The disposal of these products in the environment has raised concerns pertaining to their potential harmfulness for beneficial organisms. The objective of this study was to evaluate the influence of the shape, surface chemistry, size and carrier of three additives containing silver and one with titanium dioxide (TiO 2 ) on microcrustacean survival. Daphnia magna was used as a bioindicator for acute exposure test in suspensions from 0.0001 to 10,000ppm. Ceriodaphnia dubia was used for chronic test in TiO 2 suspensions from 0.001 to 100ppm. D. magna populations presented high susceptibility to all silver based additives, with 100% mortality after 24hr of exposure. A different result was found in the acute experiments containing TiO 2 suspensions, with mortality rates only after 48hr of incubation. Even on acute and chronic tests, TiO 2 did not reach a linear concentration-response versus mortality, with 1ppm being more toxic than 10,000ppm on acute test and 0.001 more toxic than 0.01ppm on chronic assay. Silver based material toxicity was attributed to silver itself, and had no relation to either form (nano or ion) or carrier (silica, phosphate glass or bentonite). TiO 2 demonstrated to have a low acute toxicity against D. magna. Copyright © 2016. Published by Elsevier B.V.

21 CFR 211.94 - Drug product containers and closures.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Drug product containers and closures. 211.94 Section 211.94 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... and use that can cause deterioration or contamination of the drug product. (c) Drug product containers...

Micellized sequestered silver atoms and small silver clusters

International Nuclear Information System (INIS)

Borgarello, E.; Lawless, D.; Serpone, N.; Pelizzetti, E.; Meisel, D.

1990-01-01

Pulse radiolysis was used to examine the nature of the silver species obtained when an aqueous solution containing sequestered Ag + ions was reduced by hydrated electrons in the presence of a surfactant macrocyclic crown ether, labeled L, and/or a maltoside surfactant. The initially formed product is the Ag 0 (L) species which rapidly loses its ligand (half-life ≤5 μs) and reacts with another Ag + (L) ion to form Ag 2 + (L). The latter species decays by a bimolecular process to form the Ag 4 2+ (L) n species at a faster rate than its ligand free analogue. Ultimately, colloidal metallic silver, (Ag) n , forms which is stabilized by the surfactant moieties. No long-term stability to the reduced monomolecular species could be obtained

Silver powder effectiveness and mechanism of silver paste on silicon solar cells

International Nuclear Information System (INIS)

Tsai, Jung-Ting; Lin, Shun-Tian

2013-01-01

Highlights: ► Optimizing the silver paste in 80–85 wt.%. ► Optimizing its particle size in 1–1.5 μm spherical powder. ► The sheet resistance is 4 mΩ/sq during the 860 °C sintering process. ► Redox reaction cause Ag crystallites to grow on the interface. ► A thin layer of silicon oxide (75–150 nm) was formed. - Abstract: Since the silver paste plays a major role in the mass production of silicon solar cells, this work has succeeded in optimizing the silver paste in 80–85 wt.% and optimizing its particle size in 1–1.5 μm spherical powder. As the firing temperature is increased, the growth trend of silver grain is improved. The result of this work has showed that the lowest sheet resistance is 4 mΩ/sq during the 860 °C sintering process. The scanning electron microscope (SEM) observation has showed that the formation of silver oxide is formed during the melting process of glass and triggered redox reaction of Ag crystallites to grow on the interface. It has proven by transmission electron microscope (TEM) that a thin layer of silicon oxide (75–150 nm) was formed, respectively.

Synergistic antibacterial effect of silver and ebselen against multidrug-resistant Gram-negative bacterial infections.

Science.gov (United States)

Zou, Lili; Lu, Jun; Wang, Jun; Ren, Xiaoyuan; Zhang, Lanlan; Gao, Yu; Rottenberg, Martin E; Holmgren, Arne

2017-08-01

Multidrug-resistant (MDR) Gram-negative bacteria account for a majority of fatal infections, and development of new antibiotic principles and drugs is therefore of outstanding importance. Here, we report that five most clinically difficult-to-treat MDR Gram-negative bacteria are highly sensitive to a synergistic combination of silver and ebselen. In contrast, silver has no synergistic toxicity with ebselen on mammalian cells. The silver and ebselen combination causes a rapid depletion of glutathione and inhibition of the thioredoxin system in bacteria. Silver ions were identified as strong inhibitors of Escherichia coli thioredoxin and thioredoxin reductase, which are required for ribonucleotide reductase and DNA synthesis and defense against oxidative stress. The bactericidal efficacy of silver and ebselen was further verified in the treatment of mild and acute MDR E. coli peritonitis in mice. These results demonstrate that thiol-dependent redox systems in bacteria can be targeted in the design of new antibacterial drugs. The silver and ebselen combination offers a proof of concept in targeting essential bacterial systems and might be developed for novel efficient treatments against MDR Gram-negative bacterial infections. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

Production of biodiesel from sunflower oil using highly catalytic bimetallic gold–silver core–shell nanoparticle

International Nuclear Information System (INIS)

Banerjee, Madhuchanda; Dey, Binita; Talukdar, Jayanta; Chandra Kalita, Mohan

2014-01-01

Bimetallic Gold–silver core–shell nanoparticles (Au@Ag NPs) were synthesized at room temperature, where gold nanoparticles (AuNPs) served as seeds for continuous deposition of silver atoms on its surface. The core–shell structure was examined by UV–vis spectroscopy, transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis. The catalytic activity of these nanoparticles toward biodiesel production from Sunflower oil through transesterification was studied. The confirmation for biofuel synthesis was performed using Fourier Transform Infra-Red (FTIR) spectroscopy. Fuel properties are determined by standard ASTM (American society for Testing and Materials) protocols. Our observations show that at certain catalyst concentration, temperature and reaction time, highest yield of biodiesel (86.9%) is attained. The fuel properties of the synthesized biofuel are at par with standard biofuel. Further, the catalyst showed sustained activity for 3 cycles of transesterification. - Highlights: • Gold–silver core–shell NPs were used for biofuel synthesis from sunflower oil. • At the optimized condition, biodiesel yield of 86.9% was achieved. • Fuel properties of the biofuel synthesized are at par with standard biofuel. • The catalyst showed sustained activity for 3 cycles of transesterification

Drugs from the Oceans: Marine Natural Products as Leads for Drug Discovery.

Science.gov (United States)

Altmann, Karl-Heinz

2017-10-25

The marine environment harbors a vast number of species that are the source of a wide array of structurally diverse bioactive secondary metabolites. At this point in time, roughly 27'000 marine natural products are known, of which eight are (were) at the origin of seven marketed drugs, mostly for the treatment of cancer. The majority of these drugs and also of drug candidates currently undergoing clinical evaluation (excluding antibody-drug conjugates) are unmodified natural products, but synthetic chemistry has played a central role in the discovery and/or development of all but one of the approved marine-derived drugs. More than 1000 new marine natural products have been isolated per year over the last decade, but the pool of new and unique structures is far from exhausted. To fully leverage the potential offered by the structural diversity of marine-produced secondary metabolites for drug discovery will require their broad assessment for different bioactivities and the productive interplay between new fermentation technologies, synthetic organic chemistry, and medicinal chemistry, in order to secure compound supply and enable lead optimization.

Zoological and productivity aspects of silver-fir die-back

Energy Technology Data Exchange (ETDEWEB)

Eichhorn, O.

1985-08-25

Using more recent findings and knowledge concerning root aphids, their taxonomy, host specificity, occurrence, distribution and damaging effect, the article shows that they are not the primary cause of silver-fir die-back despite their high level of constance and that they do not play any part in the course of the disease. Neither can other single insect species or several other insect species together which are harmful to silver firs like shoot bell-moth, bud bell-moth, weevil, longicorn and bark beetle, be blamed to be the primary cause of fir die-back. The article discusses reasons why constance and abundance of the bark beetle is surprisingly low even in seriously diseased trees. External appearance of the health condition of trees (proportion of dried-out crown or stag-headedness, number of needle-leaf generations, stork-nest-type crown configuration) and their rate of annual growth agree well. No phytopathogenic nematodes were detected in the inner bark/sapwood area of the trunks and in the roots of diseased silver firs. Nematodes, therefore, are ruled out as a primary cause of fir die-back.

Biosynthesis of silver nanoparticles by Aspergillus niger , Fusarium ...

African Journals Online (AJOL)

... scanning electron microscope (SEM). Results indicate the synthesis of silver nanoparticles in the reaction mixture. The synthesis of nanoparticles would be suitable for developing a microbial nanotechnology biosynthesis process for mass scale production. Keywords: Silver nanoparticles, biosynthesis, fungi, Aspergillus.

Colloidal Silver Not Approved for Treating Animals

OpenAIRE

Bagley, Clell V, DVM

1997-01-01

FDA has received reports that products containing colloidal silver are being promoted for use in the treatment of mastitis and other serious disease conditions of dairy cattle, as well as for various conditions of companion animals. For example, FDA’s Center for Veterinary Medicine has received reports from the Agency's regional milk specialists and State inspectors that colloidal silver products have been found on some dairy farms. Also, recent articles in some farm newspapers and journals p...

77 FR 840 - Pricing for 2012 America the Beautiful Quarters® Products and American Eagle Silver Dollars

Science.gov (United States)

2012-01-06

... DEPARTMENT OF THE TREASURY United States Mint Pricing for 2012 America the Beautiful Quarters[supreg] Products and American Eagle Silver Dollars AGENCY: United States Mint, Department of the Treasury. ACTION: Notice. SUMMARY: The United States Mint is announcing 2012 pricing for America the Beautiful...

Biosynthesis and structural characterization of silver nanoparticles from bacterial isolates

International Nuclear Information System (INIS)

Zaki, Sahar; El Kady, M.F.; Abd-El-Haleem, Desouky

2011-01-01

Graphical abstract: In this study five bacterial isolates belong to different genera were found to be able to biosynthesize silver nanoparticles. Biosynthesis and spectral characterization are reported here. Highlights: → About 300 bacterial isolates were screened for their ability to produce nanosilvers → Five of them were potential candidates for synthesis of silver nanoparticles → Production of silver nanoparticles was examined using UV-Vis, XRD, SEM and EDS. → The presence of nanoparticles with all five bacterial isolates was confirmed. -- Abstract: This study aimed to develop a green process for biosynthesis of silver nanomaterials by some Egyptian bacterial isolates. This target was achieved by screening an in-house culture collection consists of 300 bacterial isolates for silver nanoparticle formation. Through screening process, it was observed that strains belonging to Escherichia coli (S30, S78), Bacillus megaterium (S52), Acinetobacter sp. (S7) and Stenotrophomonas maltophilia (S54) were potential candidates for synthesis of silver nanoparticles. The extracellular production of silver nanoparticles by positive isolates was investigated by UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results demonstrated that UV-visible spectrum of the aqueous medium containing silver ion showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy micrograph showed formation of silver nanoparticles in the range of 15-50 nm. XRD-spectrum of the silver nanoparticles exhibited 2θ values corresponding to the silver nanocrystal that produce in hexagonal and cubic crystal configurations with different plane of orientation. In addition, the signals of the silver atoms were observed by EDS-spectrum analysis that confirms the presence of silver nanoparticles (AgNPs) in all positive

Green synthesis of silver nanoparticles and silver colloidal solutions

International Nuclear Information System (INIS)

Nguyen Thi Phuong Phong; Ngo Hoang Minh; Ngo Vo Ke Thanh; Dang Mau Chien

2009-01-01

In this paper, silver colloidal solutions have been synthesized rapidly in green conditions by using microwave irradiation and non-toxic chemistry substances (acid oxalic, silver nitrate, polyvinyl pyrolidone (PVP; Mw = 55 000)). The particle size and morphology of these solutions can be controlled by altering several factors like the time, the power of microwave exposure, and the ratio of silver oxalate and PVP etc. The silver nanoparticles were fabricated by thermal decomposition of silver oxalate. The synthesized silver colloidal solutions and silver nanoparticles were characterized by several analytical techniques like UV- VIS, XRD, TEM, FESEM/EDS and ICP-AAS studies. Finally, we used the synthesized silver colloidal solutions for antibacterial purpose. The obtained results showed that the synthesized silver colloidal solutions, even at very low concentrations, have highly efficient anti-bacterial property.

Multifunctional inulin tethered silver-graphene quantum dots nanotheranostic module for pancreatic cancer therapy.

Science.gov (United States)

Nigam Joshi, Preeti; Agawane, Sachin; Athalye, Meghana C; Jadhav, Vrushali; Sarkar, Dhiman; Prakash, Rajiv

2017-09-01

Cancer nanotechnology is an emerging area of cancer diagnosis and therapy. Although considerable progress has been made for targeted drug delivery systems to deliver anticancer agents to particular site of interest, new nanomaterials are frequently being developed and explored for better drug delivery efficiency. In the present work, we have explored a novel nanoformulation based on silver-graphene quantum dots (Ag-GQDs) nanocomposite for its successful implementation for pancreatic cancer specific drug delivery in wistar rats. Carboxymethyl inulin (CMI); a modified variant of natural polysaccharide inulin is tethered with the nanocomposite via carbodiimide coupling to enhance the biocompatibility of nanoformulation. Experiments are performed to investigate the cytotoxicity reduction of silver nanoparticles after inulin tethering as well as anticancer efficacy of the system using 5-Fluorouracil (5-FU) as model drug. SEM, TEM, FT-IR, UV-vis, photoluminescence and anti proliferative assays (MTT) are performed for characterisation of the nanocomposite. Hyaluronic acid (HA) is conjugated as targeting moiety for CD-44 (cancer stem cell marker) to fabricate a complete targeted drug delivery vehicle specific for pancreatic cancer. In the present work two prime objectives were achieved; mitigation the toxicity of silver nanoparticles by inulin coating and it's in vivo application for pancreatic cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

In vitro screening of silver nanoparticles and ionic silver using neural networks yields differential effects on spontaneous activity and pharmacological responses.

Science.gov (United States)

Silver nanoparticles (AgNPs) are used in a wide range of consumer and medical products because of their antimicrobial and antifungal properties. Numerous studies have demonstrated that silver can translocate to distal organs following exposure to AgNPs. Therefore, it is essential...

Synthesis of battery grade reduced silver powder

International Nuclear Information System (INIS)

Qadeer, R.; Hameed, M.; Ikram, S.; Munir, A.

2002-01-01

Process for production of battery grade reduced silver powder, an active positive material for zinc-silver oxide batteries, having specific characteristics has been optimized and the synthesized reduced silver powder was characterized. Results reveal that the values of bulk density (1.25 0.1 g/cm3) and activity (73.27 %) of synthesized reduced silver powder lies within the recommended range for use as battery material. It has purity ≥ 98% and contains Fe and Cu as traces in the concentration range of 30 5 ppm and 15 7 ppm respectively. Others determined values of surface and pores parameters are: surface area 2.6 .4 m2/g: pore volume 3.10 cm3/g: pore diameter 0.043 mu m and porosity 20%. XRD studies reveal that reduced silver powder has a cubic structure. (author)

21 CFR 310.509 - Parenteral drug products in plastic containers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Parenteral drug products in plastic containers... Parenteral drug products in plastic containers. (a) Any parenteral drug product packaged in a plastic... parenteral drug product for intravenous use in humans that is packaged in a plastic immediate container on or...

New Strategies in the Development of Antimicrobial Coatings: The Example of Increasing Usage of Silver and Silver Nanoparticles

Directory of Open Access Journals (Sweden)

Leo H. Koole

2011-01-01

Full Text Available Bacterial infection from medical devices is a major problem and accounts for an increasing number of deaths as well as high medical costs. Many different strategies have been developed to decrease the incidence of medical device related infection. One way to prevent infection is by modifying the surface of the devices in such a way that no bacterial adhesion can occur. This requires modification of the complete surface with, mostly, hydrophilic polymeric surface coatings. These materials are designed to be non-fouling, meaning that protein adsorption and subsequent microbial adhesion are minimized. Incorporation of antimicrobial agents in the bulk material or as a surface coating has been considered a viable alternative for systemic application of antibiotics. However, the manifestation of more and more multi-drug resistant bacterial strains restrains the use of antibiotics in a preventive strategy. The application of silver nanoparticles on the surface of medical devices has been used to prevent bacterial adhesion and subsequent biofilm formation. The nanoparticles are either deposited directly on the device surface, or applied in a polymeric surface coating. The silver is slowly released from the surface, thereby killing the bacteria present near the surface. In the last decade there has been a surplus of studies applying the concept of silver nanoparticles as an antimicrobial agent on a range of different medical devices. The main problem however is that the exact antimicrobial mechanism of silver remains unclear. Additionally, the antimicrobial efficacy of silver on medical devices varies to a great extent. Here we will review existing antimicrobial coating strategies and discuss the use of silver or silver nanoparticles on surfaces that are designed to prevent medical device related infections.

Bacterial resistance to silver nanoparticles and how to overcome it

Science.gov (United States)

Panáček, Aleš; Kvítek, Libor; Smékalová, Monika; Večeřová, Renata; Kolář, Milan; Röderová, Magdalena; Dyčka, Filip; Šebela, Marek; Prucek, Robert; Tomanec, Ondřej; Zbořil, Radek

2018-01-01

Silver nanoparticles have already been successfully applied in various biomedical and antimicrobial technologies and products used in everyday life. Although bacterial resistance to antibiotics has been extensively discussed in the literature, the possible development of resistance to silver nanoparticles has not been fully explored. We report that the Gram-negative bacteria Escherichia coli 013, Pseudomonas aeruginosa CCM 3955 and E. coli CCM 3954 can develop resistance to silver nanoparticles after repeated exposure. The resistance stems from the production of the adhesive flagellum protein flagellin, which triggers the aggregation of the nanoparticles. This resistance evolves without any genetic changes; only phenotypic change is needed to reduce the nanoparticles' colloidal stability and thus eliminate their antibacterial activity. The resistance mechanism cannot be overcome by additional stabilization of silver nanoparticles using surfactants or polymers. It is, however, strongly suppressed by inhibiting flagellin production with pomegranate rind extract.

21 CFR 340.50 - Labeling of stimulant drug products.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Labeling of stimulant drug products. 340.50 Section 340.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE STIMULANT DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE Labeling § 340.50...

Noble silver nanoparticles (AgNPs) synthesis and characterization ...

African Journals Online (AJOL)

Nanotechnology is rapidly growing with nanoparticles produced and utilized in a wide range of pharmaceutical and commercial products throughout the world. In this study, fig (Ficus carica) leaf extracts were used for ecofriendly extracellular synthesis of stable silver nanoparticles (AgNPs) by treating an aqueous silver ...

Preconcentration of silver as silver xanthate on activated carbon

International Nuclear Information System (INIS)

Ramadevi, P.; Naidu, U.V.; Naidu, G.R.K.

1988-01-01

Silver from aqueous solution was preconcentrated by adsorption on activated carbon as silver xanthate. Factors influencing the adsorption of silver were studied. Optimum conditions for the preconcentration of silver were established. (author) 9 refs.; 3 tabs

Examining the production costs of antiretroviral drugs.

Science.gov (United States)

Pinheiro, Eloan; Vasan, Ashwin; Kim, Jim Yong; Lee, Evan; Guimier, Jean Marc; Perriens, Joseph

2006-08-22

To present direct manufacturing costs and price calculations of individual antiretroviral drugs, enabling those responsible for their procurement to have a better understanding of the cost structure of their production, and to indicate the prices at which these antiretroviral drugs could be offered in developing country markets. Direct manufacturing costs and factory prices for selected first and second-line antiretroviral drugs were calculated based on cost structure data from a state-owned company in Brazil. Prices for the active pharmaceutical ingredients (API) were taken from a recent survey by the World Health Organization (WHO). The calculated prices for antiretroviral drugs are compared with quoted prices offered by privately-owned, for-profit manufacturers. The API represents the largest component of direct manufacturing costs (55-99%), while other inputs, such as salaries, equipment costs, and scale of production, have a minimal impact. The calculated prices for most of the antiretroviral drugs studied fall within the lower quartile of the range of quoted prices in developing country markets. The exceptions are those drugs, primarily for second-line therapy, for which the API is either under patent, in short supply, or in limited use in developing countries (e.g. abacavir, lopinavir/ritonavir, nelfinavir, saquinavir). The availability of data on the cost of antiretroviral drug production and calculation of factory prices under a sustainable business model provide benchmarks that bulk purchasers of antiretroviral drugs could use to negotiate lower prices. While truly significant price decreases for antiretroviral drugs will depend largely on the future evolution of API prices, the present study demonstrates that for several antiretroviral drugs price reduction is currently possible. Whether or not these reductions materialize will depend on the magnitude of indirect cost and profit added by each supplier over the direct production costs. The ability to

Physical, chemical and biological studies of gelatin/chitosan based transdermal fims with embedded silver nanoparticles

Directory of Open Access Journals (Sweden)

Sneha Paul

2015-12-01

Full Text Available Objective: To study the physical, chemical and biological properties of composite chitosangelatin transdermal film along with silver nanoparticles as binding agent and determine the compatibility of the prepared amalgamation towards wound management. Methods: Transdermal film preparations were done by solvent casting method containing different concentrations of biological synthesized silver nanoparticles. The films were characterized by using scanning electron microscope for their morphology and the determination of silver metal was done by using inductively coupled plasma atomic emission spectroscopy. Then a quantity of silver nanoparticles was further proceeded by physiochemical parameters (weight, thickness, temperature, solubility, absorption, tensile strength, in vitro drug release and skin permeation and biological parameters studies (anti-microbial, cytotoxicity and reactive oxygen species. Results: The film prepared by utilizing 2 g of gelatin and 0.5 g of chitosan exhibited better results. The physiochemical parameters studies revealed higher concentration of silver nanoparticles would give better results. In vitro drug release studies through dialysis and skin permeation showed the release of drug versus time (h. These films had shown excellent inhibition against Streptococcus and Escherichia coli species. Cytotoxicity study by MTT indicated the mild toxicity existed as the concentration of silver nanoparticles increased. Reactive oxygen species generation studies of transdermal film by using 2'7'-dichlorofluorescein diacetate assay demonstrated that the fluorescent cells were found in the higher concentration, which indicated cell damage (reactive oxygen species generated. Conclusions: Based on these observations, in vitro performances against various characteristics of transdermal film, would be utilized as a distinct dressing material and patches accessible in market.

Recovery of silver from used X-ray film using alkaline protease from ...

African Journals Online (AJOL)

Jane Erike-Etchie

2016-06-29

Jun 29, 2016 ... Silver is an important industrial metal used in several areas such as photographic and x-ray films, jewelries, silver ... field of enzyme production. It is widely used in leather industry, diagnosis process, extraction of silver, animal.

Reduced Silver Nanoparticle Phytotoxicity in Crambe abyssinica with Enhanced Glutathione Production by Overexpressing Bacterial y-Glutamylcysteine Synthase

Science.gov (United States)

Chuanxin Ma; Sudesh Chhikara; Rakesh Minocha; Stephanie Long; Craig Musante; Jason C. White; Baoshan Xing; Om Parkash Dhankher

2015-01-01

Silver nanoparticles (Ag NPs) are widely used in consumer products, and their release has raised serious concerns about the risk of their exposure to the environment and to human health. However, biochemical mechanisms by which plants counteract NP toxicity are largely unknown. We have previously engineered Crambe abyssinica plants expressing the...

Transmission electron microscopy for elucidating the impact of silver-based treatments (ionic silver versus nanosilver-containing coating) on the model yeast Saccharomyces cerevisiae

Energy Technology Data Exchange (ETDEWEB)

Despax, B; Saulou, C; Raynaud, P [Universite de Toulouse, UPS, INPT, LAPLACE, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Datas, L [Universite de Toulouse, UPS, INPT, CIRIMAT, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Mercier-Bonin, M [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France)

2011-04-29

After exposure to ionic silver or nanosilver-containing plasma coating, the same visual aspect of scanning transmission electron microscopy (STEM) images was observed for the model yeast Saccharomyces cerevisiae. The main common feature was the presence of electron-dense nodules all over the cell. However, high resolution TEM (HRTEM), STEM, energy dispersive x-ray microanalysis spectroscopy (EDS) and electron microdiffraction revealed some striking differences. Regarding ionic silver exposure, the formation of electron-dense nodules was related to the Ag{sup +} reactivity towards sulfur-containing compounds to form clusters with Ag{sub 2}S-like structures, together with the production of a few silver nanocrystals, mainly at the cell wall periphery. For nanosilver-based treatment, some sulfur-containing silver clusters preferentially located at the cell wall periphery were detected, together with nodules composed of silver, sulfur and phosphorus all over the cell. In both silver-based treatments, nitrogen and silver signals overlapped, confirming the affinity of silver entities for proteinaceous compounds. Moreover, in the case of nanosilver, interactions of silver with phosphorus-containing subcellular structures were indicated.

TTC- Based Test as an Efficient Method to Determine Antibiofilm Activity of Silver Nanoparticles

OpenAIRE

Chojniak Joanna; Biedroń Izabela; Płaza Grażyna

2017-01-01

Among metal nanoparticles, silver nanoparticles are a widely used in various life sectors such as in biomedical applications, air and water purification, food production, cosmetics, garments and in various household products. There are several methods for production of silver nanoparticles. Generally, silver nanoparticles can be prepared by chemical methods such as chemical reduction and electrochemical techniques, physical methods, and biological methods such as the use of microorganisms. Th...

Liposomal Drug Product Development and Quality: Current US Experience and Perspective.

Science.gov (United States)

Kapoor, Mamta; Lee, Sau L; Tyner, Katherine M

2017-05-01

Research in the area of liposomes has grown substantially in the past few decades. Liposomes are lipid bilayer structures that can incorporate drug substances to modify the drug's pharmacokinetic profile thereby improving drug delivery. The agency has received over 400 liposomal drug product submissions (excluding combination therapies), and there are currently eight approved liposomal drug products on the US market. In order to identify the pain points in development and manufacturing of liposomal drug products, a retrospective analysis was performed from a quality perspective on submissions for new and generic liposomal drug products. General analysis on liposomal drug product submissions was also performed. Results indicated that 96% of the submissions were Investigational New Drug (IND) applications, 3% were New Drug Applications (NDAs), and the remaining 1% was Abbreviated New Drug Applications (ANDAs). Doxorubicin hydrochloride was the most commonly used drug substance incorporated into the liposomes (31%). The majority of the liposomal products were administered via intravenous route (84%) with cancer (various types) being the most common indication (63%). From a quality perspective, major challenges during the development of liposomal drug products included identification and (appropriate) characterization of critical quality attributes of liposomal drug products and suitable control strategies during product development. By focusing on these areas, a faster and more efficient development of liposomal drug products may be achieved. Additionally, in this way, the drug review process for such products can be streamlined.

Antibacterial activity and toxicity of silver - nanosilver versus ionic silver

International Nuclear Information System (INIS)

Kvitek, L; Panacek, A; Prucek, R; Soukupova, J; Vanickova, M; Zboril, R; Kolar, M

2011-01-01

The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.

Antibacterial activity and toxicity of silver - nanosilver versus ionic silver

Energy Technology Data Exchange (ETDEWEB)

Kvitek, L; Panacek, A; Prucek, R; Soukupova, J; Vanickova, M; Zboril, R [Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, 17. Listopadu 12, 77146 Olomouc (Czech Republic); Kolar, M, E-mail: ales.panacek@upol.cz [Department of Microbiology, Faculty of Medicine and Dentistry, Palacky University, Hnevotinska 3, 77520 Olomouc (Czech Republic)

2011-07-06

The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.

Characterisation and potential migration of silver nanoparticles from commercially available polymeric food contact materials.

Science.gov (United States)

Addo Ntim, Susana; Thomas, Treye A; Begley, Timothy H; Noonan, Gregory O

2015-01-01

The potential for consumer exposure to nano-components in food contact materials (FCMs) is dependent on the migration of nanomaterials into food. Therefore, characterising the physico-chemical properties and potential for migration of constituents is an important step in assessing the safety of FCMs. A number of commercially available food storage products, purchased domestically within the United States and internationally, that claim to contain nanosilver were evaluated. The products were made of polyethylene, polypropylene and polyphenylene ether sulfone and all contained silver (0.001-36 mg kg(-1) of polymer). Silver migration was measured under various conditions, including using 3% acetic acid and water as food simulants. Low concentrations (sub-ppb levels) of silver were detected in the migration studies generally following a trend characterised by a surface desorption phenomenon, where the majority of the silver migration occurred in the first of three consecutive exposures. Silver nanoparticles were not detected in food simulants, suggesting that the silver migration may be due solely to ionic silver released into solution from oxidation of the silver nanoparticle surface. The absence of detectable silver nanoparticles was consistent with expectations from a physico-chemical view point. For the products tested, current USFDA guidance for evaluating migration from FCMs was applicable.

Optimizing clinical drug product performance

DEFF Research Database (Denmark)

Dickinson, Paul A.; Kesisoglou, Filippos; Flanagan, Talia

2016-01-01

The aim of Biopharmaceutics Risk Assessment Roadmap (BioRAM) and the BioRAM Scoring Grid is to facilitate optimization of clinical performance of drug products. BioRAM strategy relies on therapy-driven drug delivery and follows an integrated systems approach for formulating and addressing critical...... questions and decision-making (J Pharm Sci. 2014,103(11): 3777-97). In BioRAM, risk is defined as not achieving the intended in vivo drug product performance, and success is assessed by time to decision-making and action. Emphasis on time to decision-making and time to action highlights the value of well....... Application of the BioRAM Scoring Grid is illustrated using published literature. Organizational considerations for implementing BioRAM strategy, including the interactions, function, and skillsets of the BioRAM group members, are also reviewed. As a creative and innovative systems approach, we believe...

The production and sales of anti-tuberculosis drugs in China.

Science.gov (United States)

Huang, Yang-Mu; Zhao, Qi-Peng; Ren, Qiao-Meng; Peng, Dan-Lu; Guo, Yan

2016-10-04

Tuberculosis (TB) is a major infectious disease globally. Adequate and proper use of anti-TB drugs is essential for TB control. This study aims to study China's production capacity and sales situation of anti-TB drugs, and to further discuss the potential for China to contribute to global TB control. The production data of anti-TB drugs in China from 2011 to 2013 and the sales data from 2010 to 2014 were extracted from Ministry of Industry and Information Technology database of China and IMS Health database, respectively. The number of drugs was standardized to the molecular level of the key components before calculating. All data were described and analyzed by Microsoft Excel. First-line drugs were the majority in both sales (89.5 %) and production (92.3 %) of anti-TB drugs in China. The production of rifampicin held the majority share in active pharmaceutical ingredients (APIs) and finished products, whilst ethambutol and pyrazinamide were the top two sales in finished products. Fixed-dose combinations only held small percentages in total production and sales weight, though a slight increase was observed. The production and sales of streptomycin showed a tendency of decrease after 2012. The trends and proportion of different anti-TB drugs were similar in production and sales, however, the production weight was much larger than that of sales, especially for rifampicin and isoniazid. First-line drugs were the predominant medicine produced and used in China. While the low production and sales of the second-line TB drugs and FDCs rose concerns for the treatment of multiple drug resistant TB. The redundant production amount, as well as the prompt influence of national policy on drug production and sales, indicated the potential for China to better contribute to global TB control.

Biocompatible silver nanoparticles embedded in a PEG–PLA polymeric matrix for stimulated laser light drug release

International Nuclear Information System (INIS)

Neri, F.; Scala, A.; Grimato, S.; Santoro, M.; Spadaro, S.; Barreca, F.; Cimino, F.; Speciale, A.; Saija, A.; Grassi, G.; Fazio, E.

2016-01-01

The laser-induced release of a well-known hepatoprotective drug (silibinin, SLB) from a temperature-sensitive polymeric composite loaded with silver nanoparticles (Ag NPs) was investigated. The surface chemistry tuning and the specific design of Ag NPs are fundamental in view of the engineering of specific stimuli-responsive systems, able to control drug release in response to external stimuli. The release profiles of SLB from the newly synthesized PEG–PLA@Ag composite show strong dependences on laser wavelength and Ag NPs’ Surface Plasmon Resonance (SPR). The resonant laser light excites the SPR of the NPs and the absorbed energy is converted into heat due to electron–photon collisions. The heat generated from the nanometer-sized metal particles embedded within the polymer is efficient and strongly localized. The nanovector, irradiated by a relatively low-intensity laser but tuned specifically to the metal NPs’ SPR, releases the encapsulated drug with a higher efficiency than that not irradiated or irradiated with a laser wavelength far from the metal SPR. A combination of analytical techniques including UV–Vis, NMR, and FT-IR spectroscopy and scanning/transmission electron microscopy has been used to study the structural and morphological properties of the composite. The controllable specificity of this approach and the possibility of the SPR-mediated localized photothermal effect to be usefully applied in aqueous environments are the relevant advances of the proposed system for photothermal therapies that make use of visible optical radiation or for the drug delivery in proximity of the tumor cells.

Biocompatible silver nanoparticles embedded in a PEG–PLA polymeric matrix for stimulated laser light drug release

Energy Technology Data Exchange (ETDEWEB)

Neri, F. [Università di Messina, Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (Italy); Scala, A., E-mail: ascala@unime.it; Grimato, S. [Università di Messina, Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali (Italy); Santoro, M.; Spadaro, S.; Barreca, F. [Università di Messina, Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (Italy); Cimino, F.; Speciale, A.; Saija, A.; Grassi, G. [Università di Messina, Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali (Italy); Fazio, E., E-mail: enfazio@unime.it [Università di Messina, Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (Italy)

2016-06-15

The laser-induced release of a well-known hepatoprotective drug (silibinin, SLB) from a temperature-sensitive polymeric composite loaded with silver nanoparticles (Ag NPs) was investigated. The surface chemistry tuning and the specific design of Ag NPs are fundamental in view of the engineering of specific stimuli-responsive systems, able to control drug release in response to external stimuli. The release profiles of SLB from the newly synthesized PEG–PLA@Ag composite show strong dependences on laser wavelength and Ag NPs’ Surface Plasmon Resonance (SPR). The resonant laser light excites the SPR of the NPs and the absorbed energy is converted into heat due to electron–photon collisions. The heat generated from the nanometer-sized metal particles embedded within the polymer is efficient and strongly localized. The nanovector, irradiated by a relatively low-intensity laser but tuned specifically to the metal NPs’ SPR, releases the encapsulated drug with a higher efficiency than that not irradiated or irradiated with a laser wavelength far from the metal SPR. A combination of analytical techniques including UV–Vis, NMR, and FT-IR spectroscopy and scanning/transmission electron microscopy has been used to study the structural and morphological properties of the composite. The controllable specificity of this approach and the possibility of the SPR-mediated localized photothermal effect to be usefully applied in aqueous environments are the relevant advances of the proposed system for photothermal therapies that make use of visible optical radiation or for the drug delivery in proximity of the tumor cells.

Rapid and Efficient Synthesis of Silver Nanofluid Using Electrical Discharge Machining

Directory of Open Access Journals (Sweden)

Kuo-Hsiung Tseng

2013-01-01

Full Text Available The electrical discharge machining (EDM system has been proven feasible as a rapid and efficient method for silver nanofluid preparation. This study prepared the silver nano-fluid via EDM and investigated the relationship between its process parameters and product characteristics. The prior study had found that the silver nano-fluid prepared by EDM contained both silver nanoparticles and silver ions. Silver ions had revealed the cause of the high suspension of the silver nanoparticles. To examine the relationship between the stability of silver nanofluid and the process parameters, this study quantified the relationship of process parameters to the material removal rate (MRR of silver electrode and silver ion output rate (IOR in the fluid, in order to achieve the most effective process parameter condition. Furthermore, the stability of silver nano-fluid was analyzed by various devices, including UV-Vis spectroscopy, size-distribution, and Zeta-potential analyzer. The effects of MRR, IOR, particle size, Zeta-potential, and optical properties of silver nanofluid under different process parameters are also discussed.

银镜生产线操作工艺%Production Operating Technology of Silver-mirror Line

Institute of Scientific and Technical Information of China (English)

徐卫民; 杨晨; 梁中生

2011-01-01

详细介绍了银镜生产线的实际操作工艺,阐述了每道工序的注意事项。%The practical operating technology of silver-mirror production line was described in details and the matters need attention at every stage were also presented.

Synthesis and electrical properties of silver nanoplates for electronic applications

Directory of Open Access Journals (Sweden)

Xiong Nana

2015-06-01

Full Text Available In this paper, silver nanoplates of 100 to 500 nm size were synthesized by reduction of silver nitrate with N,Ndimethylformamide, using poly(vinylpyrolidone as a surfactant and ferric chloride as a controlling agent, at 120 to 160 °C for 5 to 24 hours. The influence of the concentration of ferric chloride, the reaction temperature and reaction time on the morphology of the product has been investigated by transmission electron microscopy, scanning electron microscopy and UV-Vis spectroscopy. The results indicated that the products obtained at the low reaction temperature and short reaction time in the presence of FeCl3 in the reaction solution were in the form of silver nanoplates, whose morphology was mainly triangular and hexagonal. In addition, the size and thickness of the nanoplates increased with increasing of the FeCl3 concentration. At a high reaction temperature and long reaction time, the truncated triangle and hexagonal nanoplates were mainly produced. Furthermore, the sintering behavior of nanoplates was studied and the results showed that sintering of the silver nanoplates started at 180 °C, and a typical sintering behavior was observed at higher temperatures. The incorporation of the silver nanoplates into the polymer matrix with micro-sized silver flakes led to an increase in the matrix resistivity in almost all cases, especially at high fractions and low curing temperatures. The curing temperature had an influence on the resistivity of the conductive adhesives filled with micro-sized silver flakes and silver nanoplates due to sintering of the silver nanoplates.

Transfer Study of Silver Nanoparticles in Poultry Production

NARCIS (Netherlands)

Gallocchio, F.; Biancotto, G.; Cibin, V.; Losasso, C.; Belluco, S.; Peters, R.; Bemmel, G. van; Cascio, C.; Weigel, S.; Tromp, P.; Gobbo, F.; Catania, S.; Ricci, A.

2017-01-01

Silver nanoparticles (AgNPs) are of interest due to their antimicrobial activity and are seen as potential candidates to replace antibiotics in animal husbandry. A few studies have focused on this new application, but they lack any considerations about residual accumulation of AgNPs in edible animal

Transfer Study of Silver Nanoparticles in Poultry Production

NARCIS (Netherlands)

Gallocchio, Federica; Biancotto, Giancarlo; Cibin, Veronica; Losasso, Carmen; Belluco, Simone; Peters, Ruud; Bemmel, van Greet; Cascio, Claudia; Weigel, Stefan; Tromp, Peter C.; Gobbo, Federica; Catania, Salvatore; Ricci, Antonia

2017-01-01

Silver nanoparticles (AgNPs) are of interest due to their antimicrobial activity and are seen as potential candidates to replace antibiotics in animal husbandry. A few studies have focused on this new application, but they lack any considerations about residual accumulation of AgNPs in edible

Antimicrobial potentials of silver colloidal (nanorods) on clinical ...

African Journals Online (AJOL)

Antimicrobial resistance in developing countries has long been an issue of major concern. Nanotechnology has become an eye opener for the intervention on multiple drug resistance organisms. In this study we investigated the antimicrobial potentials of Silver Nitrate (nanorods) solution used in managing infectious ...

Structural characterization of silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Garcia, Paulo Ricardo; Sousa, Edi Carlos Pereira de; Pontuschka, Walter Maigon; Oliveira, Cristiano Luis Pinto de, E-mail: pauloricardoafg@yahoo.com.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica

2016-07-01

Full text: Due to magnetic, optical and electrical properties metallic nanoparticles have been extensively studied to potential applications in biosensor production, separation of biological molecules, image techniques, drug delivery among several others. For such applications, it is crucial to have crystals with morphology and well defined structure. In this work we presented a detailed structured characterization of silver nanoparticles using small angle x-rays and light scattering methods. The comparison and correlation of these results with electron microscopy images permitted the determination of interesting structural parameters for the studied systems. The oscillations of the intensity curve of SAXS data reveal that this sample has particles with reasonable stability and well defined sizes. The mean radius obtained from the size distribution curve is in good agreement with the ones obtained by TEM images. As will be shown, the combination of several techniques and the correct analysis for the obtained experimental data provides unique information on the structure of the studied systems. (author)

Controlled synthesis and characterization of hollow flower-like silver nanostructures

Directory of Open Access Journals (Sweden)

Eid KAM

2012-03-01

Full Text Available Kamel AM Eid, Hassan ME AzzazyNovel Diagnostics and Therapeutics Group, Yousef Jameel Science and Technology Research Center, School of Sciences and Engineering, The American University in Cairo, New Cairo, EgyptBackground: The synthesis of anisotropic silver nanoparticles is a time-consuming process and involves the use of expensive toxic chemicals and specialized laboratory equipment. The presence of toxic chemicals in the prepared anisotropic silver nanostructures hindered their medical application. The authors have developed a fast and inexpensive method for the synthesis of three-dimensional hollow flower-like silver nanostructures without the use of toxic chemicals.Methods: In this method, silver nitrate was reduced using dextrose in presence of trisodium citrate as a capping agent. Sodium hydroxide was added to enhance reduction efficacy of dextrose and reduce time of synthesis. The effects of all four agents on the shape and size of silver nanostructures were investigated.Results: Robust hollow flower-like silver nanostructures were successfully synthesized and ranged in size from 0.2 µm to 5.0 µm with surface area between 25–240 m2/g. Changing the concentration of silver nitrate, dextrose, sodium hydroxide, and trisodium citrate affected the size and shape of the synthesized structures, while changing temperature had no effect.Conclusion: The proposed method is simple, safe, and allows controlled synthesis of anisotropic silver nanostructures, which may represent promising tools as effective antimicrobial agents and for in vitro diagnostics. The synthesized hollow nanostructures may be used for enhanced drug encapsulation and sustained release.Keywords: silver nanoparticles, 3D hollow, flower-like, green synthesis

Optimization of silver nanoparticles production by laser ablation in water using a 150-ps laser

International Nuclear Information System (INIS)

Stašić, J.; Živković, Lj.; Trtica, M.

2016-01-01

Silver nanoparticles were synthesized by laser ablation in liquid (water) using a 150-ps Nd:YAG laser. Due to their extraordinary characteristics, especially when obtained by this method providing high purity and high stability of colloids, silver NPs are nowadays highly important in various applications. The objective of this study was to optimize the process parameters in order to achieve the highest possible yield while retaining small particle size. Yield/mass concentration of the obtained particles was measured depending on different parameters: time of irradiation, pulse energy, position regarding the focus, and number of irradiation locations. The conditions providing relatively high yield, small particle size, highest production rate, and highest efficiency are 7 mJ, 15-min irradiation time (9000 pulses), and target position ∼4 mm in front of the lens focus. The results are compared with the results obtained by the longer nanosecond as well as the ultrashort pulsed lasers. A possible physical explanation is given.

Optimization of silver nanoparticles production by laser ablation in water using a 150-ps laser

Energy Technology Data Exchange (ETDEWEB)

Stašić, J.; Živković, Lj.; Trtica, M., E-mail: etrtica@vinca.rs [University of Belgrade, Institute of Nuclear Sciences “Vinča” (Serbia)

2016-12-15

Silver nanoparticles were synthesized by laser ablation in liquid (water) using a 150-ps Nd:YAG laser. Due to their extraordinary characteristics, especially when obtained by this method providing high purity and high stability of colloids, silver NPs are nowadays highly important in various applications. The objective of this study was to optimize the process parameters in order to achieve the highest possible yield while retaining small particle size. Yield/mass concentration of the obtained particles was measured depending on different parameters: time of irradiation, pulse energy, position regarding the focus, and number of irradiation locations. The conditions providing relatively high yield, small particle size, highest production rate, and highest efficiency are 7 mJ, 15-min irradiation time (9000 pulses), and target position ∼4 mm in front of the lens focus. The results are compared with the results obtained by the longer nanosecond as well as the ultrashort pulsed lasers. A possible physical explanation is given.

Silver-palladium catalysts for the direct synthesis of hydrogen peroxide

Science.gov (United States)

Khan, Zainab; Dummer, Nicholas F.; Edwards, Jennifer K.

2017-11-01

A series of bimetallic silver-palladium catalysts supported on titania were prepared by wet impregnation and assessed for the direct synthesis of hydrogen peroxide, and its subsequent side reactions. The addition of silver to a palladium catalyst was found to significantly decrease hydrogen peroxide productivity and hydrogenation, but crucially increase the rate of decomposition. The decomposition product, which is predominantly hydroxyl radicals, can be used to decrease bacterial colonies. The interaction between silver and palladium was characterized using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The results of the TPR and XPS indicated the formation of a silver-palladium alloy. The optimal 1% Ag-4% Pd/TiO2 bimetallic catalyst was able to produce approximately 200 ppm of H2O2 in 30 min. The findings demonstrate that AgPd/TiO2 catalysts are active for the synthesis of hydrogen peroxide and its subsequent decomposition to reactive oxygen species. The catalysts are promising for use in wastewater treatment as they combine the disinfectant properties of silver, hydrogen peroxide production and subsequent decomposition. This article is part of a discussion meeting issue 'Providing sustainable catalytic solutions for a rapidly changing world'.

Towards localization of engineered silver nanoparticles in Pseudokirchneriella subcapitata

DEFF Research Database (Denmark)

Jensen, Louise Helene Søgaard; Sørensen, Sara Nørgaard; Hartmann, Nanna Isabella Bloch

Silver nanoparticles have increased cytotoxic properties compared to larger particles. Reflecting these properties, engineered silver nanoparticles are now added to an increasing number of consumer products often labelled as anti-bacterial. These particles are presently considered the fastest...... growing nanotechnology application. Accordingly, silver nanoparticles are now postulated to be released into the sewerage systems and wider environment in increasing quantities. Here they could potentially interfere with aquatic life and this ongoing project aims to localize possible particles taken up...

Transfer Study of Silver Nanoparticles in Poultry Production.

Science.gov (United States)

Gallocchio, Federica; Biancotto, Giancarlo; Cibin, Veronica; Losasso, Carmen; Belluco, Simone; Peters, Ruud; van Bemmel, Greet; Cascio, Claudia; Weigel, Stefan; Tromp, Peter; Gobbo, Federica; Catania, Salvatore; Ricci, Antonia

2017-05-10

Silver nanoparticles (AgNPs) are of interest due to their antimicrobial activity and are seen as potential candidates to replace antibiotics in animal husbandry. A few studies have focused on this new application, but they lack any considerations about residual accumulation of AgNPs in edible animal tissues and animal products. In this research, a 22 day in vivo study was carried out by oral administration of 20 nm spherical PVP coated AgNPs to hens. Six doses of approximately 1 mg kg -1 of AgNPs-PVP each were administered to animals throughout the experimentation. Atomic absorption spectroscopy (AAS) was used for quantitative determination of residual total Ag in different organs and matrices. The analyses showed that Ag accumulates in livers (concentration ranging from 141 μg kg -1 to 269 μg kg -1 ) and yolks (concentration ranging from 20 μg kg -1 to 49 μg kg -1 ) but not in muscles, kidneys, and albumen belonging to hens of the treated group (tG2). Ag was not detected in animals of the control group (uG1) (i.e., total Ag animals. spICP-MS highlighted that part of residual Ag found in livers (about 5-20%) is in NP form with an average dimension of approximately 20 nm. SEM-EDX technique confirmed the presence of AgNPs only in livers of treated animals. The results show that feeding AgNPs to hens may become a source of consumer exposure to AgNPs. As far as we know this is the first study showing transfer of AgNPs or reaction products thereof from animal feed to animal products.

Oral toxicity of silver ions, silver nanoparticles and colloidal silver--a review.

Science.gov (United States)

Hadrup, Niels; Lam, Henrik R

2014-02-01

Orally administered silver has been described to be absorbed in a range of 0.4-18% in mammals with a human value of 18%. Based on findings in animals, silver seems to be distributed to all of the organs investigated, with the highest levels being observed in the intestine and stomach. In the skin, silver induces a blue-grey discoloration termed argyria. Excretion occurs via the bile and urine. The following dose-dependent animal toxicity findings have been reported: death, weight loss, hypoactivity, altered neurotransmitter levels, altered liver enzymes, altered blood values, enlarged hearts and immunological effects. Substantial evidence exists suggesting that the effects induced by particulate silver are mediated via silver ions that are released from the particle surface. With the current data regarding toxicity and average human dietary exposure, a Margin of Safety calculation indicates at least a factor of five before a level of concern to the general population is reached. Copyright © 2013 Elsevier Inc. All rights reserved.

Silver nano - a trove for retinal therapies.

Science.gov (United States)

Kalishwaralal, Kalimuthu; Barathmanikanth, Selvaraj; Pandian, Sureshbabu Ram Kumar; Deepak, Venkatraman; Gurunathan, Sangiliyandi

2010-07-14

Pathological retinal angiogenesis (neovascularization) is one of the most feared complications among retinal diseases, leading to visual impairment and irreversible blindness. Recent findings made by us on therapeutic applications of biologically synthesized silver nanoparticles (AgNPs) against VEGF induced retinal endothelial cells, elucidates the effectual inhibitory activities of AgNPs over the downstream signaling pathways (Src and AKT/PI3K) leading to retinal angiogenesis. The current review focuses on the imperative role of VEGF induced angiogenesis in the development of retinal neovascularization and despite the fact that several VEGF targeting ocular drugs are available; the review examines the need for a cost economic alternative, thereby suggesting the role of AgNPs as an emerging economic ocular drug for retinal therapies. The current technologies available for the development of targeted and controlled release of drugs is being discussed and a model has been proposed for the amenable targeting mechanism, by which Poly gamma glutamic acid (PGA) capsulated AgNPs conjugated to cyclic RGD peptides carry out a sustained controlled release specifically targeting the neovascularization cells and induce apoptosis unaffecting the normal retinal cells. These constructs consequently affirm the futuristic application of silver nanoparticles as a boon to ocular therapies. Copyright (c) 2010 Elsevier B.V. All rights reserved.

21 CFR 333.150 - Labeling of first aid antibiotic drug products.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Labeling of first aid antibiotic drug products... First Aid Antibiotic Drug Products § 333.150 Labeling of first aid antibiotic drug products. (a... identifies the product as a “first aid antibiotic.” (b) Indications. The labeling of the product states...

21 CFR 347.50 - Labeling of skin protectant drug products.

Science.gov (United States)

2010-04-01

... omitted. (f) Products containing only cocoa butter, petrolatum, or white petrolatum identified in § 347.10... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Labeling of skin protectant drug products. 347.50... (CONTINUED) DRUGS FOR HUMAN USE SKIN PROTECTANT DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE Labeling § 347...

Oral toxicity of silver ions, silver nanoparticles and colloidal silver – a review

DEFF Research Database (Denmark)

Hadrup, Niels; Lam, Henrik Rye

2014-01-01

Orally administered silver has been described to be absorbed in a range of 0.4-18% in mammals with a human value of 18%. Based on findings in animals, silver seems to be distributed to all of the organs investigated, with the highest levels being observed in the intestine and stomach. In the skin......, silver induces a blue-grey discoloration termed argyria. Excretion occurs via the bile and urine. The following dose-dependent animal toxicity findings have been reported: death, weight loss, hypoactivity, altered neurotransmitter levels, altered liver enzymes, altered blood values, enlarged hearts...... and immunological effects. Substantial evidence exists suggesting that the effects induced by particulate silver are mediated via silver ions that are released from the particle surface. With the current data regarding toxicity and average human dietary exposure, a Margin of Safety calculation indicates at least...

Application of the flotation process in the silver recovery from the wastes generated during the silvery semi-products manufacturing

OpenAIRE

B. Oleksiak; A. Blacha-Grzechnik; G. Siwiec

2012-01-01

In this work, the results of the flotation process application in the silver recovery from the wastes generated during the silvery semi-products manufacturing, are shown. The flotation process parameters, i.e. time of process, rotation frequency, gas flow rate and flotation reagents, were optimized.

Microalgae associated Brevundimonas sp. MSK 4 as the nano particle synthesizing unit to produce antimicrobial silver nanoparticles.

Science.gov (United States)

Rajamanickam, Karthic; Sudha, S S; Francis, Mebin; Sowmya, T; Rengaramanujam, J; Sivalingam, Periyasamy; Prabakar, Kandasamy

2013-09-01

The biosynthesis of silver nanoparticles and its antimicrobial property was studied using bacteria isolated from Spirulina products. Isolated bacteria were identified as Bacillus sp. MSK 1 (JX495945), Staphylococcus sp. MSK 2 (JX495946), Bacillus sp. MSK 3 (JX495947) and Brevundimonas sp. MSK 4 (JX495948). Silver nanoparticles (AgNPs) were synthesized using bacterial culture filtrate with AgNO3. The initial syntheses of Ag nanoparticles were characterized by UV-vis spectrophotometer (by measuring the color change to intense brown). Fourier Transform Infrared Spectroscopy (FTIR) study showed evidence that proteins are possible reducing agents and Energy-dispersive X-ray (EDX) study showing the metal silver as major signal. The structure of AgNPs was determined by Scanning electron microscopy (SEM) and X-ray diffraction (XRD). Synthesized Ag nanoparticles with an average size of 40-65 nm have antimicrobial property against human pathogens like Proteus vulgaris, Salmonella typhi, Vibrio cholera, Streptococcus sp., Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Among the isolates Brevundimonas sp. MSK 4 alone showed good activity in both synthesis of AgNPs and antimicrobial activity. This work demonstrates the possible use of biological synthesized silver nanoparticles to combat the drug resistant problem. Copyright © 2013 Elsevier B.V. All rights reserved.

Drug-device combination products: regulatory landscape and market growth.

Science.gov (United States)

Bayarri, L

2015-08-01

Combination products are therapeutic and diagnostic products that combine drugs, devices and/or biological products, leading to safer and more effective treatments thanks to careful and precise drug targeting, local administration and individualized therapy. These technologies can especially benefit patients suffering from serious diseases and conditions such as cancer, heart disease, multiple sclerosis and diabetes, among others. On the other hand, drug-device combination products have also introduced a new dynamic in medical product development, regulatory approval and corporate interaction. Due to the increasing integration of drugs and devices observed in the latest generation of combination products, regulatory agencies have developed specific competences and regulations over the last decade. Manufacturers are required to fully understand the specific requirements in each country in order to ensure timely and accurate market access of new combination products, and the development of combination products involves a very specific pattern of interactions between manufacturers and regulatory agencies. The increased sophistication of the products brought to market over the last couple of decades has accentuated the need to develop drugs and devices collaboratively using resources from both industries, fostering the need of business partnering and technology licensing. This review will provide a global overview of the market trends, as well as (in the last section) an analysis of the drug-device combination products approved by the FDA during the latest 5 years. Copyright 2015 Prous Science, S.A.U. or its licensors. All rights reserved.

Bioaccumulation of silver in Daphnia magna:Waterborne and dietary exposure to nanoparticles and dissolved silver

NARCIS (Netherlands)

Ribeiro, Fabianne; van Gestel, C.A.M.; Pavlaki, M.D.; Azevedo, S.; Soares, A.M.V.M.; Loureiro, S.

2017-01-01

Silver nanoparticles (Ag-NP) are incorporated into commercial products as antimicrobial agents, which potentiate their emission to the environment. The toxicity of Ag-NP has been associated with the release of Ag ions (Ag

Dermal exposure potential from textiles that contain silver nanoparticles.

Science.gov (United States)

Stefaniak, Aleksandr B; Duling, Mathew G; Lawrence, Robert B; Thomas, Treye A; LeBouf, Ryan F; Wade, Eleanor E; Virji, M Abbas

2014-01-01

Factors that influence exposure to silver particles from the use of textiles are not well understood. The aim of this study was to evaluate the influence of product treatment and physiological factors on silver release from two textiles. Atomic and absorbance spectroscopy, electron microscopy, and dynamic light scattering (DLS) were applied to characterize the chemical and physical properties of the textiles and evaluate silver release in artificial sweat and saliva under varying physiological conditions. One textile had silver incorporated into fiber threads (masterbatch process) and the other had silver nanoparticles coated on fiber surfaces (finishing process). Several complementary and confirmatory analytical techniques (spectroscopy, microscopy, etc.) were required to properly assess silver release. Silver released into artificial sweat or saliva was primarily in ionic form. In a simulated "use" and laundering experiment, the total cumulative amount of silver ion released was greater for the finishing process textile (0·51±0·04%) than the masterbatch process textile (0·21±0·01%); Pmasterbatch vs finishing) used to treat textile fibers was a more influential exposure factor than physiological properties of artificial sweat or saliva.

Recovery of Silver and Gold from Copper Anode Slimes

Science.gov (United States)

Chen, Ailiang; Peng, Zhiwei; Hwang, Jiann-Yang; Ma, Yutian; Liu, Xuheng; Chen, Xingyu

2015-02-01

Copper anode slimes, produced from copper electrolytic refining, are important industrial by-products containing several valuable metals, particularly silver and gold. This article provides a comprehensive overview of the development of the extraction processes for recovering silver and gold from conventional copper anode slimes. Existing processes, namely pyrometallurgical processes, hydrometallurgical processes, and hybrid processes involving the combination of pyrometallurgical and hydrometallurgical technologies, are discussed based in part on a review of the form and characteristics of silver and gold in copper anode slimes. The recovery of silver and gold in pyrometallurgical processes is influenced in part by the slag and matte/metal chemistry and related characteristics, whereas the extraction of these metals in hydrometallurgical processes depends on the leaching reagents used to break the structure of the silver- and gold-bearing phases, such as selenides. By taking advantage of both pyrometallurgical and hydrometallurgical techniques, high extraction yields of silver and gold can be obtained using such combined approaches that appear promising for efficient extraction of silver and gold from copper anode slimes.

Modeling population exposures to silver nanoparticles present in consumer products

Science.gov (United States)

Royce, Steven G.; Mukherjee, Dwaipayan; Cai, Ting; Xu, Shu S.; Alexander, Jocelyn A.; Mi, Zhongyuan; Calderon, Leonardo; Mainelis, Gediminas; Lee, KiBum; Lioy, Paul J.; Tetley, Teresa D.; Chung, Kian Fan; Zhang, Junfeng; Georgopoulos, Panos G.

2014-11-01

Exposures of the general population to manufactured nanoparticles (MNPs) are expected to keep rising due to increasing use of MNPs in common consumer products (PEN 2014). The present study focuses on characterizing ambient and indoor population exposures to silver MNPs (nAg). For situations where detailed, case-specific exposure-related data are not available, as in the present study, a novel tiered modeling system, Prioritization/Ranking of Toxic Exposures with GIS (geographic information system) Extension (PRoTEGE), has been developed: it employs a product life cycle analysis (LCA) approach coupled with basic human life stage analysis (LSA) to characterize potential exposures to chemicals of current and emerging concern. The PRoTEGE system has been implemented for ambient and indoor environments, utilizing available MNP production, usage, and properties databases, along with laboratory measurements of potential personal exposures from consumer spray products containing nAg. Modeling of environmental and microenvironmental levels of MNPs employs probabilistic material flow analysis combined with product LCA to account for releases during manufacturing, transport, usage, disposal, etc. Human exposure and dose characterization further employ screening microenvironmental modeling and intake fraction methods combined with LSA for potentially exposed populations, to assess differences associated with gender, age, and demographics. Population distributions of intakes, estimated using the PRoTEGE framework, are consistent with published individual-based intake estimates, demonstrating that PRoTEGE is capable of capturing realistic exposure scenarios for the US population. Distributions of intakes are also used to calculate biologically relevant population distributions of uptakes and target tissue doses through human airway dosimetry modeling that takes into account product MNP size distributions and age-relevant physiological parameters.

High frequency of silver resistance genes in invasive isolates of Enterobacter and Klebsiella species.

Science.gov (United States)

Sütterlin, S; Dahlö, M; Tellgren-Roth, C; Schaal, W; Melhus, Å

2017-07-01

Silver-based products have been marketed as an alternative to antibiotics, and their consumption has increased. Bacteria may, however, develop resistance to silver. To study the presence of genes encoding silver resistance (silE, silP, silS) over time in three clinically important Enterobacteriaceae genera. Using polymerase chain reaction (PCR), 752 bloodstream isolates from the years 1990-2010 were investigated. Age, gender, and ward of patients were registered, and the susceptibility to antibiotics and silver nitrate was tested. Clonality and single nucleotide polymorphism were assessed with repetitive element sequence-based PCR, multi-locus sequence typing, and whole-genome sequencing. Genes encoding silver resistance were detected most frequently in Enterobacter spp. (48%), followed by Klebsiella spp. (41%) and Escherichia coli 4%. Phenotypical resistance to silver nitrate was found in Enterobacter (13%) and Klebsiella (3%) isolates. The lowest carriage rate of sil genes was observed in blood isolates from the neonatology ward (24%), and the highest in blood isolates from the oncology/haematology wards (66%). Presence of sil genes was observed in international high-risk clones. Sequences of the sil and pco clusters indicated that a single mutational event in the silS gene could have caused the phenotypic resistance. Despite a restricted consumption of silver-based products in Swedish health care, silver resistance genes are widely represented in clinical isolates of Enterobacter and Klebsiella species. To avoid further selection and spread of silver-resistant bacteria with a high potential for healthcare-associated infections, the use of silver-based products needs to be controlled and the silver resistance monitored. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Discovery of the silver isotopes

International Nuclear Information System (INIS)

Schuh, A.; Fritsch, A.; Ginepro, J.Q.; Heim, M.; Shore, A.; Thoennessen, M.

2010-01-01

Thirty-eight silver isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

Silver nanoparticles and silver nitrate induce high toxicity to Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio

International Nuclear Information System (INIS)

Ribeiro, Fabianne; Gallego-Urrea, Julián Alberto; Jurkschat, Kerstin; Crossley, Alison; Hassellöv, Martin; Taylor, Cameron; Soares, Amadeu M.V.M.; Loureiro, Susana

2014-01-01

Silver nanoparticles (AgNP) have gained attention over the years due to the antimicrobial function of silver, which has been exploited industrially to produce consumer goods that vary in type and application. Undoubtedly the increase of production and consumption of these silver-containing products will lead to the entry of silver compounds into the environment. In this study we have used Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio as model organisms to investigate the toxicity of AgNP and AgNO 3 by assessing different biological endpoints and exposure periods. Organisms were exposed following specific and standardized protocols for each species/endpoints, with modifications when necessary. AgNP were characterized in each test-media by Transmission Electron Microscopy (TEM) and experiments were performed by Dynamic Light Scattering (DLS) to investigate the aggregation and agglomeration behavior of AgNP under different media chemical composition and test-period. TEM images of AgNP in the different test-media showed dissimilar patterns of agglomeration, with some agglomerates inside an organic layer, some loosely associated particles and also the presence of some individual particles. The toxicity of both AgNO 3 and AgNP differ significantly based on the test species: we found no differences in toxicity for algae, a small difference for zebrafish and a major difference in toxicity for Daphnia magna. - Highlights: •Effects of silver nanoparticles and nitrate were compared in three aquatic species. •The presence of food on the immobilization assay for Daphnia magna significantly decreased AgNP toxicity. •AgNP and AgNO 3 differ in toxicity according to the test species and endpoint. •AgNP and AgNO 3 induced dissimilar abnormalities on zebrafish embryos' development. •AgNP behavior in the test media will rule its bioavailability and uptake and therefore toxicity

Silver nanoparticles and silver nitrate induce high toxicity to Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Fabianne, E-mail: ribeiro.f@ua.pt [Department of Biology and CESAM, University of Aveiro. Campus Universitario de Santiago, 3810-193. Aveiro (Portugal); Gallego-Urrea, Julián Alberto [Department of Chemistry and Molecular Biologyx, University of Gothenburg, Kemivägen 4, 41296 Gothenburg (Sweden); Jurkschat, Kerstin; Crossley, Alison [Department of Materials, Oxford University Begbroke Science Park OX5 1PF (United Kingdom); Hassellöv, Martin [Department of Chemistry and Molecular Biologyx, University of Gothenburg, Kemivägen 4, 41296 Gothenburg (Sweden); Taylor, Cameron [Department of Materials, Oxford University Begbroke Science Park OX5 1PF (United Kingdom); Soares, Amadeu M.V.M.; Loureiro, Susana [Department of Biology and CESAM, University of Aveiro. Campus Universitario de Santiago, 3810-193. Aveiro (Portugal)

2014-01-01

Silver nanoparticles (AgNP) have gained attention over the years due to the antimicrobial function of silver, which has been exploited industrially to produce consumer goods that vary in type and application. Undoubtedly the increase of production and consumption of these silver-containing products will lead to the entry of silver compounds into the environment. In this study we have used Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio as model organisms to investigate the toxicity of AgNP and AgNO{sub 3} by assessing different biological endpoints and exposure periods. Organisms were exposed following specific and standardized protocols for each species/endpoints, with modifications when necessary. AgNP were characterized in each test-media by Transmission Electron Microscopy (TEM) and experiments were performed by Dynamic Light Scattering (DLS) to investigate the aggregation and agglomeration behavior of AgNP under different media chemical composition and test-period. TEM images of AgNP in the different test-media showed dissimilar patterns of agglomeration, with some agglomerates inside an organic layer, some loosely associated particles and also the presence of some individual particles. The toxicity of both AgNO{sub 3} and AgNP differ significantly based on the test species: we found no differences in toxicity for algae, a small difference for zebrafish and a major difference in toxicity for Daphnia magna. - Highlights: •Effects of silver nanoparticles and nitrate were compared in three aquatic species. •The presence of food on the immobilization assay for Daphnia magna significantly decreased AgNP toxicity. •AgNP and AgNO{sub 3} differ in toxicity according to the test species and endpoint. •AgNP and AgNO{sub 3} induced dissimilar abnormalities on zebrafish embryos' development. •AgNP behavior in the test media will rule its bioavailability and uptake and therefore toxicity.

Patient centric drug product design in modern drug delivery as an opportunity to increase safety and effectiveness.

Science.gov (United States)

Stegemann, Sven

2018-06-01

The advances in drug delivery technologies have enabled pharmaceutical scientists to deliver a drug through various administration routes and optimize the drug release and absorption. The wide range of drug delivery systems and dosage forms represent a toolbox of technology for the development of pharmaceutical drug products but might also be a source of medication errors and nonadherence. Patient centric drug product development is being suggested as an important factor to increase therapeutic outcomes. Areas covered: Patients have impaired health and potentially disabilities and they are not medical or pharmaceutical experts but are requested to manage complex therapeutic regimens. As such the application of technology should also serve to reduce complexity, build on patients' intuition and ease of use. Patients form distinct populations based on the targeted disease, disease cluster or age group with specific characteristics or therapeutic contexts. Expert opinion: Establishing a target product and patient profile is essential to guide drug product design development. Including the targeted patient populations in the process is a prerequisite to achieve patient-centric pharmaceutical drug product design. Addressing the needs early on in the product design process, will create more universal design, avoiding the necessity for multiple product presentations to cover the different patient populations.

21 CFR 344.52 - Labeling of ear drying aid drug products.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Labeling of ear drying aid drug products. 344.52 Section 344.52 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Labeling of ear drying aid drug products. (a) Statement of identity. The labeling of the product contains...

Production of nanopoints and nanowires of silver at the surface of Si(557)

International Nuclear Information System (INIS)

Zhachuk, R.A.; Tijs, S.A.; Ol'shanetskij, B.Z.

2004-01-01

Formation of the silver nanostructures at the room temperature on the Si(557) surface containing the regular atomic stages of three interplanar distances in the height is studied through the methods of the scanning tunnel microscopy and electron Auger-spectroscopy. It is established that the oxygen adsorbed by the silicon surface from the residual atmosphere in the vacuum chamber effects the shape of the formed silver islands. The silver nanostructures of the nanowire-type, extended along the stage edges or nanopoints ordered in lines parallel to the stage edges may be formed depending on the quantity of the oxygen adsorbed on the surface [ru

Application of the flotation process in the silver recovery from the wastes generated during the silvery semi-products manufacturing

Directory of Open Access Journals (Sweden)

B. Oleksiak

2012-07-01

Full Text Available In this work, the results of the flotation process application in the silver recovery from the wastes generated during the silvery semi-products manufacturing, are shown. The flotation process parameters, i.e. time of process, rotation frequency, gas flow rate and flotation reagents, were optimized.

Green synthesis of silver nanoparticles using a Melissa officinalis leaf extract with antibacterial properties

Directory of Open Access Journals (Sweden)

Álvaro de Jesús Ruíz-Baltazar

Full Text Available The exceptional properties of the silver nanoparticles offer several applications in the biomedicine field. The development of antibiotics which are clinically useful against bacteria and drug resistant microorganisms, it is one of the main approaches of silver nanoparticles. However, it is necessary to develop environmentally friendly methods for their synthesis. In this sense, the main objective of this work is focused on to propose a simplified and efficient green synthesis of silver nanoparticles with proven antibacterial properties. The green synthesis route is based on the use of the Melissa officinalis as reducing agent of the silver ions in aqueous solution at room temperature. Complementary, the antibacterial activity of the silver nanoparticles against Staphylococcus aureus and Escherichia coli was confirmed. The silver nanoparticles obtained were characterized by transmission electron microscopy, X-ray diffraction, UV–vis, Raman and FT-IR spectroscopy. The observed results suggested that using Melissa officinalis, it is possible to performed silver nanoparticles with controlled characteristics and with significant inhibitory activity against the Staphylococcus aureus and Escherichia coli. Keywords: Green synthesis, Nanoparticles, Antibacterial effect

Biosynthesis of silver nanoparticles by plants crude extracts and ...

African Journals Online (AJOL)

The indiscriminate use of antibiotics has fuelled the development of drug resistance at an alarming rate. To overpower this burning problem, the Ag-NPs may prove to be a universal solution. Key words: Nanobiotechnology, silver nanoparticles (Ag-NPs), Emblica officinalis, Terminalia catappa and Eucalyptus hybrida.

Ultrashort peptide nanogels release in situ generated silver manoparticles to combat emerging antimicrobial resistance strains

KAUST Repository

Seferji, Kholoud; Susapto, Hepi Hari; Arab, Wafaa Talat Abdullah; Sharip, Ainur; Sundaramurthi, Dhakshinamoorthy; Rauf, Sakandar; Hauser, Charlotte

2017-01-01

Nanogels made from self-assembling ultrashort peptides (3-6 amino acids in size) are promising biomaterials for various biomedical applications such as tissue engineering, drug delivery, regenerative medicine, microbiology and biosensing.We have developed silver-releasing peptide nanogels with promising wound care applications. The peptide nanogels allow a precise control of in situ syntesized silver nanoparticles (AgNPs), using soley short UV radiation and no other chemical reducing agent. We propose these silver-releasing nanogels as excellent biomaterial to combat emerging antimicrobial resistant strains.

Ultrashort peptide nanogels release in situ generated silver manoparticles to combat emerging antimicrobial resistance strains

KAUST Repository

Seferji, Kholoud

2017-01-08

Nanogels made from self-assembling ultrashort peptides (3-6 amino acids in size) are promising biomaterials for various biomedical applications such as tissue engineering, drug delivery, regenerative medicine, microbiology and biosensing.We have developed silver-releasing peptide nanogels with promising wound care applications. The peptide nanogels allow a precise control of in situ syntesized silver nanoparticles (AgNPs), using soley short UV radiation and no other chemical reducing agent. We propose these silver-releasing nanogels as excellent biomaterial to combat emerging antimicrobial resistant strains.

Real Silver and Its Investment and Business Options

Directory of Open Access Journals (Sweden)

Novotný Josef

2016-06-01

Full Text Available The article deals with investment and business opportunities offered by silver. Silver is the metal used in industry and for investing at financial markets. The main problem related to this real commodity is the issue of “the undervaluation” of its investment options, if compared to gold. If considering silver as the investment option, its investment potential is significantly enhanced by its industrial usage. The aim of this paper is to highlight business and investment opportunities for both professionals and non professional investors at the commodity markets. The price growth of this investment and industrial metal can generate profits for the investors. And on the other hand, industries which cannot do without silver in their production may efficiently utilize the knowledge of setting up its price at the markets.

Electrospun poly(ε-caprolactone) matrices containing silver sulfadiazine complexed with β-cyclodextrin as a new pharmaceutical dosage form to wound healing: preliminary physicochemical and biological evaluation.

Science.gov (United States)

Souza, Sarah Oliveira Lamas; Cotrim, Monique Alvarenga Pinto; Oréfice, Rodrigo Lambert; Carvalho, Suzana Gonçalves; Dutra, Jessyca Aparecida Paes; de Paula Careta, Francisco; Resende, Juliana Alves; Villanova, Janaina Cecília Oliveira

2018-05-10

Cooperation between researchers in the areas of medical, pharmaceutical and materials science has facilitated the development of pharmaceutical dosage forms that elicit therapeutic effects and protective action with a single product. In addition to optimizing pharmacologic action, such dosage forms provide greater patient comfort and increase success and treatment compliance. In the present work, we prepared semipermeable bioactive electrospun fibers for use as wound dressings containing silver sulfadiazine complexed with β-cyclodextrin in a poly(Ɛ-caprolactone) nanofiber matrix aiming to reduce the direct contact between silver and skin and to modulate the drug release. Wound dressings were prepared by electrospinning, and were subjected to ATR-FT-IR and TG/DTG assays to evaluate drug stability. The hydrophilicity of the fibrous nanostructure in water and PBS buffer was studied by goniometry. Electrospun fibers permeability and swelling capacity were assessed, and a dissolution test was performed. In vitro biological tests were realized to investigate the biological compatibility and antimicrobial activity. We obtained flexible matrices that were each approximately 1.0 g in weight. The electrospun fibers were shown to be semipermeable, with water vapor transmission and swelling indexes compatible with the proposed objective. The hydrophilicity was moderate. Matrices containing pure drug modulated drug release adequately during 24 h but presented a high hemolytic index. Complexation promoted a decrease in the hemolytic index and in the drug release but did not negatively impact antimicrobial activity. The drug was released predominantly by diffusion. These results indicate that electrospun PCL matrices containing β-cyclodextrin/silver sulfadiazine inclusion complexes are a promising pharmaceutical dosage form for wound healing.

Comparison of DNA Damage and Apoptosis Induced By Silver Nanoparticle-containing Dressing Materials During Wound Healing.

Science.gov (United States)

Choi, Young Suk; Gwak, Heui-Chul; Park, Jae Keun; Lim, Ji Yun; Yeo, Eui Dong; Park, Eunseok; Kim, Junyong; Lee, Young Koo

2018-04-13

Silver nanoparticle (AgNP)-containing dressings are used worldwide for the treatment of wounds; however, many studies have indicated that AgNPs are toxic to humans and cause cell death, primarily via apoptosis. In this study, the investigators compare the apoptotic effects of various AgNP dressing materials, with the hypothesis that nanosilver would be less toxic than ionic silver. For the in vivo experiments, Sprague-Dawley (SD) and streptozotocin (STZ)-induced diabetic rats were treated with 5 dressing materials: Aquacel Ag (product A, silver ion; ConvaTec, Berkshire, UK), Acticoat (product B, AgNP; Smith & Nephew, Fort Worth, TX), Medifoam Silver (product C, silver ion; Genewel Science Co Ltd, Seongnam, South Korea), PolyMem Silver (product D, AgNP; Ferris Mfg Corp, Fort Worth, TX), and Vaseline-impregnated dressing gauze (control; Unilever, London, UK). All treatments were applied 3 times per week. After 14 days of treatment, the SD and STZ rats were euthanized, and wound samples were examined for apoptosis. The analysis included immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, Western blotting, and reverse transcription polymerase chain reaction for a semiquantitative evaluation of apoptosis. The AgNP-containing dressing materials were more cytotoxic than the silver dressings. Compared with the AgNP dressing materials, no significant levels of apoptotic factors were observed in the silver dressing-treated wounds. The TUNEL staining showed that product C-dressed wounds contained the most apoptotic cells, while some apoptotic cells were observed in product B-dressed wounds. Moreover, apoptotic gene expression was altered, including a decline in B-cell lymphoma-2 and activation of caspase-3. This was most evident in wounds treated with product C. Interestingly, apoptotic gene expression was not induced in product A-treated wounds. Finally, product D had a relatively lower silver concentration and was less toxic

21 CFR 1310.11 - Reinstatement of exemption for drug products distributed under the Food, Drug and Cosmetic Act.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Reinstatement of exemption for drug products distributed under the Food, Drug and Cosmetic Act. 1310.11 Section 1310.11 Food and Drugs DRUG ENFORCEMENT... Reinstatement of exemption for drug products distributed under the Food, Drug and Cosmetic Act. (a) The...

Subchronic oral toxicity of silver nanoparticles

Directory of Open Access Journals (Sweden)

Kim Yong

2010-08-01

Full Text Available Abstract Background The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, consumer, medicinal, pesticide, and home products; however, silver nanoparticles remain a controversial area of research with respect to their toxicity in biological and ecological systems. Results This study tested the oral toxicity of silver nanoparticles (56 nm over a period of 13 weeks (90 days in F344 rats following Organization for Economic Cooperation and Development (OECD test guideline 408 and Good Laboratory Practices (GLP. Five-week-old rats, weighing about 99 g for the males and 92 g for the females, were divided into four 4 groups (10 rats in each group: vehicle control, low-dose (30 mg/kg, middle-dose (125 mg/kg, and high-dose (500 mg/kg. After 90 days of exposure, clinical chemistry, hematology, histopathology, and silver distribution were studied. There was a significant decrease (P Conclusions The target organ for the silver nanoparticles was found to be the liver in both the male and female rats. A NOAEL (no observable adverse effect level of 30 mg/kg and LOAEL (lowest observable adverse effect level of 125 mg/kg are suggested from the present study.

Silver percutaneous absorption after exposure to silver nanoparticles: a comparison study of three human skin graft samples used for clinical applications.

Science.gov (United States)

Bianco, C; Adami, G; Crosera, M; Larese, F; Casarin, S; Castagnoli, C; Stella, M; Maina, G

2014-11-01

Silver nanoparticles (AgNPs) are increasingly applied to a wide range of materials for biomedical use. These enable a close contact with human skin, thanks to the large release of silver ions that is responsible for a broad spectrum of antimicrobial activity. Silver can permeate the skin; however, there are no data available on silver permeation through skin grafts commonly used in burns recovery. The aim of our study was to evaluate silver penetration using fresh, cryopreserved, and glycerolized human skin grafts after exposure to a suspension of AgNPs in synthetic sweat using a Franz diffusion cell apparatus for 24 h. Silver permeation profiles revealed a significantly higher permeation through glycerolized skin compared with both fresh and cryopreserved skin: 24-h silver flux penetration was 0.2 ng cm(-2) h(-1) (lag time: 8.2 h) for fresh skin, 0.3 ng cm(-2) h(-1) (lag time: 10.9 h) for cryopreserved skin, and 3.8 ng cm(-2) h(-1) (lag time: 6.3 h) for glycerolized skin. Permeation through glycerolized skin is significantly higher compared to both fresh and cryopreserved skin. This result can generate relevant clinical implications for burns treatment with products containing AgNPs. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Approved Drug Products with Therapuetic Equivalence Evaluations (Orange Book)

Data.gov (United States)

U.S. Department of Health & Human Services — The publication Approved Drug Products with Therapeutic Equivalence Evaluations (the List, commonly known as the Orange Book) identifies drug products approved on...

Size Control Technology of Silver Nanoparticles Using Electron Beam Irradiation

International Nuclear Information System (INIS)

Kang, Hyun Suk; Kim, Byungnam; Kim, Hye Won; Koo, Yong Hwan; Lee, Byung Cheol; Park, Ji Hyun; Bae, Hyung Bin; Park, Changmoon

2013-01-01

The manufacturing of silver nanoparticles using an electron beam is easy, fast, and highly productive, and it is possible at room temperature with no chemical residuals. Its various advantages therefore make this an important method for manufacturing nanoparticles such as silver, copper, and platinum. In particular, despite the use of electron beam irradiation, the results show that this method makes it possible to produce silver nanoparticles at low cost since low beam energy and low doses are used. This means that middle and high-energy electron beam accelerators are very expensive, but a low-energy electron beam accelerator has a relatively low cost of around 4-5 times, and mass production for a flow reaction without the need for extra radiation shielding is possible. Silver nanoparticles are of great interest to many researchers owing to their ability to be used in many applications such as catalysis, nanoelectronics, optical filters, electromagnetic interference shielding, surface Raman scattering, medical supplies, fabrics, cosmetics, hygiene and kitchen supplies, and electric home appliances

Size Control Technology of Silver Nanoparticles Using Electron Beam Irradiation

Energy Technology Data Exchange (ETDEWEB)

Kang, Hyun Suk; Kim, Byungnam; Kim, Hye Won; Koo, Yong Hwan; Lee, Byung Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Ji Hyun [Univ. of Science and Technology, Daejeon (Korea, Republic of); Bae, Hyung Bin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Park, Changmoon [Chungnam National Univ., Daejeon (Korea, Republic of)

2013-12-15

The manufacturing of silver nanoparticles using an electron beam is easy, fast, and highly productive, and it is possible at room temperature with no chemical residuals. Its various advantages therefore make this an important method for manufacturing nanoparticles such as silver, copper, and platinum. In particular, despite the use of electron beam irradiation, the results show that this method makes it possible to produce silver nanoparticles at low cost since low beam energy and low doses are used. This means that middle and high-energy electron beam accelerators are very expensive, but a low-energy electron beam accelerator has a relatively low cost of around 4-5 times, and mass production for a flow reaction without the need for extra radiation shielding is possible. Silver nanoparticles are of great interest to many researchers owing to their ability to be used in many applications such as catalysis, nanoelectronics, optical filters, electromagnetic interference shielding, surface Raman scattering, medical supplies, fabrics, cosmetics, hygiene and kitchen supplies, and electric home appliances.

Reinforcement of Conducting Silver-based Materials

Directory of Open Access Journals (Sweden)

Heike JUNG

2014-09-01

Full Text Available Silver is a well-known material in the field of contact materials because of its high electrical and thermal conductivity. However, due to its bad mechanical and switching properties, silver alloys or reinforcements of the ductile silver matrix are required. Different reinforcements, e. g. tungsten, tungsten carbide, nickel, cadmium oxide or tin oxide, are used in different sectors of switches. To reach an optimal distribution of these reinforcements, various manufacturing techniques (e. g. powder blending, preform infiltration, wet-chemical methods, internal oxidation are being used for the production of these contact materials. Each of these manufacturing routes offers different advantages and disadvantages. The mechanical alloying process displays a successful and efficient method to produce particle-reinforced metal-matrix composite powders. This contribution presents the obtained fine disperse microstructure of tungsten-particle-reinforced silver composite powders produced by the mechanical alloying process and displays this technique as possible route to provide feedstock powders for subsequent consolidation processes. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4889

Using Nonexperts for Annotating Pharmacokinetic Drug-Drug Interaction Mentions in Product Labeling: A Feasibility Study.

Science.gov (United States)

Hochheiser, Harry; Ning, Yifan; Hernandez, Andres; Horn, John R; Jacobson, Rebecca; Boyce, Richard D

2016-04-11

Because vital details of potential pharmacokinetic drug-drug interactions are often described in free-text structured product labels, manual curation is a necessary but expensive step in the development of electronic drug-drug interaction information resources. The use of nonexperts to annotate potential drug-drug interaction (PDDI) mentions in drug product label annotation may be a means of lessening the burden of manual curation. Our goal was to explore the practicality of using nonexpert participants to annotate drug-drug interaction descriptions from structured product labels. By presenting annotation tasks to both pharmacy experts and relatively naïve participants, we hoped to demonstrate the feasibility of using nonexpert annotators for drug-drug information annotation. We were also interested in exploring whether and to what extent natural language processing (NLP) preannotation helped improve task completion time, accuracy, and subjective satisfaction. Two experts and 4 nonexperts were asked to annotate 208 structured product label sections under 4 conditions completed sequentially: (1) no NLP assistance, (2) preannotation of drug mentions, (3) preannotation of drug mentions and PDDIs, and (4) a repeat of the no-annotation condition. Results were evaluated within the 2 groups and relative to an existing gold standard. Participants were asked to provide reports on the time required to complete tasks and their perceptions of task difficulty. One of the experts and 3 of the nonexperts completed all tasks. Annotation results from the nonexpert group were relatively strong in every scenario and better than the performance of the NLP pipeline. The expert and 2 of the nonexperts were able to complete most tasks in less than 3 hours. Usability perceptions were generally positive (3.67 for expert, mean of 3.33 for nonexperts). The results suggest that nonexpert annotation might be a feasible option for comprehensive labeling of annotated PDDIs across a broader

Preparation and protection of silver nanoparticles with chitosan derivative

International Nuclear Information System (INIS)

Nguyen Thi Kim Cuc; Cao Van Du; Nguyen Cuu Khoa; Tran Ngoc Quyen

2013-01-01

In this paper, nano silver solution is prepared and stabilized by chitosan dihydroxyphenyl acetamide (CDHPA). Chitosan is a natural carbohydrate polymer deriving from chitin that has biodegradable, biocompatible, antibacterial and antifungal properties, so when conjugation of the polymer and silver nanoparticles could be expected to increase bactericidal features of the obtained product. The chemical and physical methods were used to characterize the chitosan derivative such as transmission spectrum (UV-Vis), IR spectrum, nuclear magnetic resonance (1H-NMR). Morphology of the obtained nano silver particles were observed by transmission electron microscopy (TEM). (author)

Effect of silver nanoparticles on human mesenchymal stem cell differentiation

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Christina Sengstock

2014-11-01

Full Text Available Background: Silver nanoparticles (Ag-NP are one of the fastest growing products in nano-medicine due to their enhanced antibacterial activity at the nanoscale level. In biomedicine, hundreds of products have been coated with Ag-NP. For example, various medical devices include silver, such as surgical instruments, bone implants and wound dressings. After the degradation of these materials, or depending on the coating technique, silver in nanoparticle or ion form can be released and may come into close contact with tissues and cells. Despite incorporation of Ag-NP as an antibacterial agent in different products, the toxicological and biological effects of silver in the human body after long-term and low-concentration exposure are not well understood. In the current study, we investigated the effects of both ionic and nanoparticulate silver on the differentiation of human mesenchymal stem cells (hMSCs into adipogenic, osteogenic and chondrogenic lineages and on the secretion of the respective differentiation markers adiponectin, osteocalcin and aggrecan.Results: As shown through laser scanning microscopy, Ag-NP with a size of 80 nm (hydrodynamic diameter were taken up into hMSCs as nanoparticulate material. After 24 h of incubation, these Ag-NP were mainly found in the endo-lysosomal cell compartment as agglomerated material. Cytotoxicity was observed for differentiated or undifferentiated hMSCs treated with high silver concentrations (≥20 µg·mL−1 Ag-NP; ≥1.5 µg·mL−1 Ag+ ions but not with low-concentration treatments (≤10 µg·mL−1 Ag-NP; ≤1.0 µg·mL−1 Ag+ ions. Subtoxic concentrations of Ag-NP and Ag+ ions impaired the adipogenic and osteogenic differentiation of hMSCs in a concentration-dependent manner, whereas chondrogenic differentiation was unaffected after 21 d of incubation. In contrast to aggrecan, the inhibitory effect of adipogenic and osteogenic differentiation was confirmed by a decrease in the secretion of

Detection of colloidal silver chloride near solubility limit

Science.gov (United States)

Putri, K. Y.; Adawiah, R.

2018-03-01

Detection of nanoparticles in solution has been made possible by several means; one of them is laser-induced breakdown detection (LIBD). LIBD is able to distinguish colloids of various sizes and concentrations. This technique has been used in several solubility studies. In this study, the formation of colloids in a mixed system of silver nitrate and sodium chloride was observed by acoustic LIBD. Silver chloride has low solubility limit, therefore LIBD measurement is appropriate. Silver and chloride solutions with equal concentrations, set at below and above the solubility of silver chloride as the expected solid product, were mixed and the resulting colloids were observed. The result of LIBD measurement showed that larger particles were present as more silver and chloride introduced. However, once the concentrations exceeded the solubility limit of silver chloride, the detected particle size seemed to be decreasing, hence suggested the occurrence of coprecipitation process. This phenomenon indicated that the ability of LIBD to detect even small changes in colloid amounts might be a useful tool in study on formation and stability of colloids, i.e. to confirm whether nanoparticles synthesis has been successfully performed and whether the system is stable or not.

Interpretation of neutron activation analysis data of ancient silver

International Nuclear Information System (INIS)

Meyers, P.; van Zelst, L.; Sayre, E.V.

1976-01-01

Results from work on Sasanian silver and objects from related periods and geographic provenances are used to demonstrate that analytical data in combination with other properties can be used with reasonable success in establishing groups of objects of common geographic provenances, in providing information on the production, use, and distribution of silver metal, and on ancient metal working techniques

Antibacterial silver nanocluster/silica composite coatings on stainless steel

Energy Technology Data Exchange (ETDEWEB)

Ferraris, M.; Perero, S. [Politecnico di Torino, Department of Applied Science and Technology, Torino, C.so Duca degli Abruzzi 24, I-10129 (Italy); Ferraris, S., E-mail: sara.ferraris@polito.it [Politecnico di Torino, Department of Applied Science and Technology, Torino, C.so Duca degli Abruzzi 24, I-10129 (Italy); Miola, M.; Vernè, E. [Politecnico di Torino, Department of Applied Science and Technology, Torino, C.so Duca degli Abruzzi 24, I-10129 (Italy); Skoglund, S. [KTH Royal Institute of Technology, Div. Surface and Corrosion Science, Dr. Kristinas v. 51, SE-100 44 (Sweden); Blomberg, E. [KTH Royal Institute of Technology, Div. Surface and Corrosion Science, Dr. Kristinas v. 51, SE-100 44 (Sweden); SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces, P.O. Box 5607, SE-114 86 Stockholm (Sweden); Odnevall Wallinder, I. [KTH Royal Institute of Technology, Div. Surface and Corrosion Science, Dr. Kristinas v. 51, SE-100 44 (Sweden)

2017-02-28

Highlights: • A silver nanocluster-silica composite coating sputter-deposited onto stainless steel. • Good adhesion and resistance upon cleaning with NaOH, H{sub 2}SO{sub 4} and detergents. • Low release of silver ions and no release as silver nanoparticles. • Good antibacterial activity against S. aureus even after heating to 450 °C. • Good antibacterial activity shown during cheese production. - Abstract: A coating made of silver nanocluster/silica composites has been deposited, via a radio frequency (RF) co-sputtering technique, for the first time onto stainless steel (AISI 304L) with the aim to improve its antibacterial properties. Different thermal treatments after coating deposition have been applied in order to optimize the coating adhesion, cohesion and its antibacterial properties. Its applicability has been investigated at realistic conditions in a cheese production plant. The physico-chemical characteristics of the coatings have been analyzed by means of different bulk and surface analytical techniques. Field emission scanning electron microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM) were employed to assess coating morphology, composition, surface roughness, wetting properties, size and local distribution of the nanoparticles within the coating. Tape tests were used to determine the adhesion/cohesion properties of the coating. The amount and time-dependence of released silver in solutions of acetic acid, artificial water, artificial tap water and artificial milk were determined by means of Atomic Absorption Spectroscopy (AAS). The antibacterial effect of the coating was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus in compliance with National Committee for Clinical Laboratory Standards (NCCLS) and AATCC 147 standards. The Ahearn test was performed to measure the adhesion of bacteria to the coated stainless steel

Antibacterial silver nanocluster/silica composite coatings on stainless steel

International Nuclear Information System (INIS)

Ferraris, M.; Perero, S.; Ferraris, S.; Miola, M.; Vernè, E.; Skoglund, S.; Blomberg, E.; Odnevall Wallinder, I.

2017-01-01

Highlights: • A silver nanocluster-silica composite coating sputter-deposited onto stainless steel. • Good adhesion and resistance upon cleaning with NaOH, H_2SO_4 and detergents. • Low release of silver ions and no release as silver nanoparticles. • Good antibacterial activity against S. aureus even after heating to 450 °C. • Good antibacterial activity shown during cheese production. - Abstract: A coating made of silver nanocluster/silica composites has been deposited, via a radio frequency (RF) co-sputtering technique, for the first time onto stainless steel (AISI 304L) with the aim to improve its antibacterial properties. Different thermal treatments after coating deposition have been applied in order to optimize the coating adhesion, cohesion and its antibacterial properties. Its applicability has been investigated at realistic conditions in a cheese production plant. The physico-chemical characteristics of the coatings have been analyzed by means of different bulk and surface analytical techniques. Field emission scanning electron microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM) were employed to assess coating morphology, composition, surface roughness, wetting properties, size and local distribution of the nanoparticles within the coating. Tape tests were used to determine the adhesion/cohesion properties of the coating. The amount and time-dependence of released silver in solutions of acetic acid, artificial water, artificial tap water and artificial milk were determined by means of Atomic Absorption Spectroscopy (AAS). The antibacterial effect of the coating was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus in compliance with National Committee for Clinical Laboratory Standards (NCCLS) and AATCC 147 standards. The Ahearn test was performed to measure the adhesion of bacteria to the coated stainless steel surface

75 FR 65362 - Oncologic Drugs Advisory Committee; Notice of Meeting

Science.gov (United States)

2010-10-22

... Hampshire Ave., Silver Spring, MD 20993-0002. Information regarding special accommodations due to a... Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Ave., Bldg. 31, rm. 2417, Silver...) Soft Gelatin Capsules, [[Page 65363

A primer of drug safety surveillance: an industry perspective. Part II: Product labeling and product knowledge.

Science.gov (United States)

Allan, M C

1992-01-01

To place the fundamentals of clinical drug safety surveillance in a conceptual framework that will facilitate understanding and application of adverse drug event data to protect the health of the public and support a market for pharmaceutical manufacturers' products. Part II of this series discusses specific issues regarding product labeling, such as developing the labeling, changing the labeling, and the legal as well as commercial ramifications of the contents of the labeling. An adverse event report scenario is further analyzed and suggestions are offered for maintaining the product labeling as an accurate reflection of the drug safety surveillance data. This article also emphasizes the necessity of product knowledge in adverse event database management. Both scientific and proprietary knowledge are required. Acquiring product knowledge is a part of the day-to-day activities of drug safety surveillance. A knowledge of the history of the product may forestall adverse publicity, as shown in the illustration. This review uses primary sources from the federal laws (regulations), commentaries, and summaries. Very complex topics are briefly summarized in the text. Secondary sources, ranging from newspaper articles to judicial summaries, illustrate the interpretation of adverse drug events and opportunities for drug safety surveillance intervention. The reference materials used were articles theoretically or practically applicable in the day-to-day practice of drug safety surveillance. The role of clinical drug safety surveillance in product monitoring and drug development is described. The process of drug safety surveillance is defined by the Food and Drug Administration regulations, product labeling, product knowledge, and database management. Database management is subdivided into the functions of receipt, retention, retrieval, and review of adverse event reports. Emphasis is placed on the dynamic interaction of the components of the process. Suggestions are offered

Characterization of SNARE Cleavage Products Generated by Formulated Botulinum Neurotoxin Type-A Drug Products

Directory of Open Access Journals (Sweden)

Jack Xie

2010-08-01

Full Text Available The study evaluated substrate cleavage product(s generated by three botulinum neurotoxin serotype A (BoNT/A medicinal drug products utilizing a novel and highly specific, light-chain activity, high-performance liquid chromatography (LCA-HPLC method. Samples were reacted with a commercially available BoNT/A fluorescent substrate derived from the SNAP-25 sequence. Reaction products were separated by reversed-phase HPLC. The method detected an atypical cleavage pattern by one of the formulated drug products. IncobotulinumtoxinA produced two cleavage fragments rather than the single fragment typically generated by BoNT/A. Identification confirmed the secondary cleavage at a position corresponding to SNAP-25 Arg198–Ala199 (normal BoNT/A cleavage is Gln197–Arg198. Arg198–Ala199 is also the cleavage site for trypsin and serotype C toxin. Normal cleavage was observed for all other BoNT/A drug product samples, as well as 900-kD and 150-kD bulk toxin BoNT/A. The reason for this unexpected secondary cleavage pattern by one formulated BoNT/A drug product is unknown. Possible explanations include a contaminating protease and/or damage to the 150-kD type-A toxin causing nonspecific substrate recognition and subsequent cleavage uncharacteristic of type-A toxin. The BoNT/A drug products were also analyzed via the LCA-HPLC assay using a commercial BoNT/C fluorescent substrate derived from the syntaxin sequence. Cleavage of the serotype C substrate by incobotulinumtoxinA was also confirmed whilst neither of the other drug products cleaved the syntaxin substrate.

Review of Drug Quality and Security Act of 2013: The Drug Supply Chain Security Act (DSCSA

Directory of Open Access Journals (Sweden)

Elona Gjini

2016-10-01

Full Text Available The Drug Supply Chain Security Act (DSCSA signed into law in November 27, 2013 by president Obama creates a uniform national standard for tracing drug products through the supply chain. The goal of DQSA is to enhance FDA’s ability to help protect consumers by detecting and removing potential dangerous products from the pharmaceutics distribution supply chain. A new electronic, interoperable system will identify and trace only prescription drugs in the finished form for human use while distributed in the United States. The purpose of this review was to shed light on a complex and complicated process that it will require cooperation between FDA and drug manufactures, wholesale drug distributors, repackagers and dispensers. The implementation of the DSCSA is based on several law requirements and FDA has developed a schedule with time frames for each of them to be executed over a 10-year period. From this review, FDA recommendations are provided through the FDA Guidance on Identifying Suspect Product document to help trading partners and provide information about the risk of suspect drugs entering the supply chain. Moreover, FDA organized on April 5-6, 2016 in Silver Spring, MD a public workshop to gather valuable feedback from stakeholders who shared their input about the implementation of the new electronic system and its requirements. By the end of 2023, a unified system will provide easier data exchange and less errors, and will increase the safety and security of the pharmaceutical distribution supply chain.   Type: Student Project

Radiation synthesis of silver nanostructures in cotton matrix

International Nuclear Information System (INIS)

Chmielewska, Dagmara; Sartowska, Bożena

2012-01-01

Cotton is one of the most popular natural fibres, composed mainly of cellulose, which finds a wide range of applications in paper, textile and health care products industry. Researchers have focused their interest on the synthesis of cotton nanocomposites, which enhances its mechanical, thermal and antimicrobial properties by the incorporation of various nanoparticles into the cotton matrix. Silver is one of the most popular antimicrobial agents with a wide spectrum of antibacterial and antifungal activity that results from a complex mechanism of its interactions with the cells of harmful microorganism. In this work, electron beam radiation was applied to synthesise silver nanostructures in cotton fibres. Investigations of the influence of the initial silver salt concentration on the size and distribution of the obtained silver nanostructures were carried out. A detailed characterisation of these nanocomposites with SEM-BSE and EDS methods was performed. TGA and DSC analyses were performed to assess the influence of different size silver nanoparticles and the effect of electron beam irradiation on the thermal properties of cotton fibres. A microbiological investigation to determine the antibacterial activity of Ag-cotton nanocomposites was carried out. - Highlights: ► Ag NPs embedded in cotton matrix were synthesised by electron beam irradiation. ► Concentration of silver salt solution influences on size of silver nanoparticles. ► Silver content as well as irradiation affect thermal properties of cotton fabrics. ► Ag-cotton nanocomposites exhibit antibacterial activity against bacteria and fungi.

A study of the decomposition of silver permanganate at high temperatures with an x-ray diffractometer

International Nuclear Information System (INIS)

De Witt, B.

1978-12-01

A study is made of the thermal decay products of silver permanganate at temperatures between 100 degrees Celsius and 800 degrees Celsius. Previous studies have shown that silver permanganate and the decomposition of silver permanganate decay into an amorphous product and remains in that state until the temperature is higher than 350 degrees Celsius. The amorphous phase is tested at different temperatures

Success rates for product development strategies in new drug development.

Science.gov (United States)

Dahlin, E; Nelson, G M; Haynes, M; Sargeant, F

2016-04-01

While research has examined the likelihood that drugs progress across phases of clinical trials, no research to date has examined the types of product development strategies that are the most likely to be successful in clinical trials. This research seeks to identify the strategies that are most likely to reach the market-those generated using a novel product development strategy or strategies that combine a company's expertise with both drugs and indications, which we call combined experience strategies. We evaluate the success of product development strategies in the drug development process for a sample of 2562 clinical trials completed by 406 US pharmaceutical companies. To identify product development strategies, we coded each clinical trial according to whether it consisted of an indication or a drug that was new to the firm. Accordingly, a clinical trial that consists of both an indication and a drug that were both new to the firm represents a novel product development strategy; indication experience is a product development strategy that consists of an indication that a firm had tested previously in a clinical trial, but with a drug that was new to the firm; drug experience is a product development strategy that consists of a drug that the firm had prior experience testing in clinical trials, but with an indication that was new to the firm; combined experience consists of both a drug and an indication that the firm had experience testing in clinical trials. Success rates for product development strategies across clinical phases were calculated for the clinical trials in our sample. Combined experience strategies had the highest success rate. More than three and a half percent (0·036) of the trials that combined experience with drugs and indications eventually reached the market. The next most successful strategy is drug experience (0·025) with novel strategies trailing closely (0·024). Indication experience strategies are the least successful (0·008

Deposition of silver layer on different substrates

Science.gov (United States)

Krzemiński, J.; Kiełbasiński, K.; Szałapak, J.; Jakubowska, M.; MłoŻniak, A.; Zwierkowska, E.

2015-09-01

The hole process of producing continuous layer with silver nanoparticles is presented in this paper. First the ink preparation and then the spray process is shown and discussed. The silver layers were obtained on sodium glass substrate. Three different ink carriers were considered and the best one has been chosen. Spray coating process was carried out using special spray can. After obtaining sprayed layers the samples were sintered in several temperatures to investigate the lowest suitable sintering temperature. After that layers resistivity were measured. Then the silver layers were cracked to produce breakthrough fracture that was investigated by a scanning electron microscope. In this paper, the authors investigated the spray coating technique as an alternative to electroplating and other techniques, considering layer resistivity, thickness and production process.

Green synthesis of silver nanoparticles using biopolymers, carboxymethylated-curdlan and fucoidan

International Nuclear Information System (INIS)

Leung, Thomas Chun-Yiu; Wong, Chung Kai; Xie Yong

2010-01-01

There is a growing need in developing a reliable and eco-friendly methodology for the synthesis of metallic nanoparticles, which may be applied for many nanotechnological applications. Natural compounds such as biopolymers are one of the resources which could be used for this purpose. The present study involves the development of a simple, ecological and user-friendly method in synthesizing silver nanoparticles by using carboxymethylated-curdlan or fucoidan as reducing and stabilizing agents. Reduction of silver ions by these biopolymers occurred when heating at 100 deg. C, led to the formation of silver nanoparticles in the range of 40-80 nm in dimensions. The silver nanoparticles were formed readily within 10-15 min. Morphological observation and characterization of the silver nanoparticles were performed by using dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and UV-vis absorption spectrophotometer. The size of silver nanoparticles can be controlled by using different concentrations of carboxymethylated-curdlan, fucoidan or silver nitrate. This way of silver nanoparticles preparation is easy, fast, user-friendly and suitable for large-scale production.

Caffeine citrate - Is it a silver bullet in neonatology?

Science.gov (United States)

Shrestha, Bikash; Jawa, Gaurav

2017-10-01

Caffeine citrate is one of the most prescribed drug in the present day NICU for apnea. Its efficacy, tolerability, wide therapeutic index and safety margin has made it the drug of choice among the methylxanthines. Its therapeutic uses in apnea of prematurity, mechanical ventilation, bronchopulmonary dysplasia has made it a "silver bullet" in neonatology. However, there are still controversies surrounding this drug. This review is aimed to update the reader about the basic pharmacology, current therapeutic uses, adverse effects, controversies as well as present and future research of caffeine. Copyright © 2017. Published by Elsevier B.V.

Silver niobates

International Nuclear Information System (INIS)

Tanirbergenov, B.; Rozhenko, S.P.

1979-01-01

By means of determination of residual concentrations and pH measurements investigated are the AgNO 3 -KNbO 3 -H 2 O, AgNO 3 -K 3 NbO 4 -H 2 O, AgNO 3 -K 8 Nb 16 O 19 -H 2 O systems and established is formation of meta-, ortho-and hexaniobates of silver. AgNbO 3 x H 2 O, Ag 8 Nb 6 O 19 x 6H 2 O and Ag 3 NbO 3 x 2.5H 2 O are separated from aqueous solution. Using the methods of differential-thermal, thermogravimetric and X-ray-phase analyses it is shown that silver metaniobate transforms into the crystal state at 530 deg C. Ortho- and hexaniobate of silver decompose at 500 deg C with formation of silver metaniobate and metal silver

Natural Products for Drug Discovery in the 21st Century: Innovations for Novel Drug Discovery

Directory of Open Access Journals (Sweden)

Nicholas Ekow Thomford

2018-05-01

Full Text Available The therapeutic properties of plants have been recognised since time immemorial. Many pathological conditions have been treated using plant-derived medicines. These medicines are used as concoctions or concentrated plant extracts without isolation of active compounds. Modern medicine however, requires the isolation and purification of one or two active compounds. There are however a lot of global health challenges with diseases such as cancer, degenerative diseases, HIV/AIDS and diabetes, of which modern medicine is struggling to provide cures. Many times the isolation of “active compound” has made the compound ineffective. Drug discovery is a multidimensional problem requiring several parameters of both natural and synthetic compounds such as safety, pharmacokinetics and efficacy to be evaluated during drug candidate selection. The advent of latest technologies that enhance drug design hypotheses such as Artificial Intelligence, the use of ‘organ-on chip’ and microfluidics technologies, means that automation has become part of drug discovery. This has resulted in increased speed in drug discovery and evaluation of the safety, pharmacokinetics and efficacy of candidate compounds whilst allowing novel ways of drug design and synthesis based on natural compounds. Recent advances in analytical and computational techniques have opened new avenues to process complex natural products and to use their structures to derive new and innovative drugs. Indeed, we are in the era of computational molecular design, as applied to natural products. Predictive computational softwares have contributed to the discovery of molecular targets of natural products and their derivatives. In future the use of quantum computing, computational softwares and databases in modelling molecular interactions and predicting features and parameters needed for drug development, such as pharmacokinetic and pharmacodynamics, will result in few false positive leads in drug

Natural Products for Drug Discovery in the 21st Century: Innovations for Novel Drug Discovery.

Science.gov (United States)

Thomford, Nicholas Ekow; Senthebane, Dimakatso Alice; Rowe, Arielle; Munro, Daniella; Seele, Palesa; Maroyi, Alfred; Dzobo, Kevin

2018-05-25

The therapeutic properties of plants have been recognised since time immemorial. Many pathological conditions have been treated using plant-derived medicines. These medicines are used as concoctions or concentrated plant extracts without isolation of active compounds. Modern medicine however, requires the isolation and purification of one or two active compounds. There are however a lot of global health challenges with diseases such as cancer, degenerative diseases, HIV/AIDS and diabetes, of which modern medicine is struggling to provide cures. Many times the isolation of "active compound" has made the compound ineffective. Drug discovery is a multidimensional problem requiring several parameters of both natural and synthetic compounds such as safety, pharmacokinetics and efficacy to be evaluated during drug candidate selection. The advent of latest technologies that enhance drug design hypotheses such as Artificial Intelligence, the use of 'organ-on chip' and microfluidics technologies, means that automation has become part of drug discovery. This has resulted in increased speed in drug discovery and evaluation of the safety, pharmacokinetics and efficacy of candidate compounds whilst allowing novel ways of drug design and synthesis based on natural compounds. Recent advances in analytical and computational techniques have opened new avenues to process complex natural products and to use their structures to derive new and innovative drugs. Indeed, we are in the era of computational molecular design, as applied to natural products. Predictive computational softwares have contributed to the discovery of molecular targets of natural products and their derivatives. In future the use of quantum computing, computational softwares and databases in modelling molecular interactions and predicting features and parameters needed for drug development, such as pharmacokinetic and pharmacodynamics, will result in few false positive leads in drug development. This review

Caffeine citrate – Is it a silver bullet in neonatology?

Directory of Open Access Journals (Sweden)

Bikash Shrestha

2017-10-01

Full Text Available Caffeine citrate is one of the most prescribed drug in the present day NICU for apnea. Its efficacy, tolerability, wide therapeutic index and safety margin has made it the drug of choice among the methylxanthines. Its therapeutic uses in apnea of prematurity, mechanical ventilation, bronchopulmonary dysplasia has made it a “silver bullet” in neonatology. However, there are still controversies surrounding this drug. This review is aimed to update the reader about the basic pharmacology, current therapeutic uses, adverse effects, controversies as well as present and future research of caffeine.

Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

International Nuclear Information System (INIS)

Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi

2015-01-01

The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO 3 aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi

Lessons from innovation in drug-device combination products.

Science.gov (United States)

Couto, Daniela S; Perez-Breva, Luis; Saraiva, Pedro; Cooney, Charles L

2012-01-01

Drug-device combination products introduced a new dynamic on medical product development, regulatory approval, and corporate interaction that provide valuable lessons for the development of new generations of combination products. This paper examines the case studies of drug-eluting stents and transdermal patches to facilitate a detailed understanding of the challenges and opportunities introduced by combination products when compared to previous generations of traditional medical or drug delivery devices. Our analysis indicates that the largest barrier to introduce a new kind of combination products is the determination of the regulatory center that is to oversee its approval. The first product of a new class of combination products offers a learning opportunity for the regulator and the sponsor. Once that first product is approved, the leading regulatory center is determined, and the uncertainty about the entire class of combination products is drastically reduced. The sponsor pioneering a new class of combination products assumes a central role in reducing this uncertainty by advising the decision on the primary function of the combination product. Our analysis also suggests that this decision influences the nature (pharmaceutical, biotechnology, or medical devices) of the companies that will lead the introduction of these products into the market, and guide the structure of corporate interaction thereon. Copyright © 2011 Elsevier B.V. All rights reserved.

Roll-to-Roll Production of Transparent Silver-Nanofiber-Network Electrodes for Flexible Electrochromic Smart Windows.

Science.gov (United States)

Lin, Sen; Bai, Xiaopeng; Wang, Haiyang; Wang, Haolun; Song, Jianan; Huang, Kai; Wang, Chang; Wang, Ning; Li, Bo; Lei, Ming; Wu, Hui

2017-11-01

Electrochromic smart windows (ECSWs) are considered as the most promising alternative to traditional dimming devices. However, the electrode technology in ECSWs remains stagnant, wherein inflexible indium tin oxide and fluorine-doped tin oxide are the main materials being used. Although various complicated production methods, such as high-temperature calcination and sputtering, have been reported, the mass production of flexible and transparent electrodes remains challenging. Here, a nonheated roll-to-roll process is developed for the continuous production of flexible, extralarge, and transparent silver nanofiber (AgNF) network electrodes. The optical and mechanical properties, as well as the electrical conductivity of these products (i.e., 12 Ω sq -1 at 95% transmittance) are comparable with those AgNF networks produced via high-temperature sintering. Moreover, the as-prepared AgNF network is successfully assembled into an A4-sized ECSW with short switching time, good coloration efficiency, and flexibility. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Green Synthesis of Silver Nanoparticles Using Sodium Alginate and Lignosulphonic Acid Blends

Science.gov (United States)

Thakur, Amrita; Reddy, Giridhar

2017-08-01

A simple method based on the principles of green chemistry has been developed to synthesize stable silver nanoparticles (AgNP) for possible biomedical applications. Blend of sodium alginate (SA) and lignosulphonic acid (LS) prepared in the ratio of 80/20 mass percent respectively was used as reducing and stabilizing agent. This blend is biocompatible and has shown drug release ability under physiological conditions. Use of blend has an added advantage as LS has the ability to reduce silver while the blend matrix acts as a stabilizing agent. Effect of precursor concentration (AgNO3) and temperature was investigated. Progress of synthesis was monitored using UV-Vis spectroscopy. Higher temperature and lower silver nitrate concentration showed better synthesis of AgNP.

Green synthesis of silver nanoparticles from marigold flower and its synergistic antimicrobial potential

Directory of Open Access Journals (Sweden)

Hemali Padalia

2015-09-01

Full Text Available In the present study, silver nanoparticles were synthesized using flower broth of Tagetes erecta as reductant by a simple and eco-friendly route. The aqueous silver ions when exposed to flower broth were reduced and resulted in green synthesis of silver nanoparticles. The silver nanoparticles were characterized by UV–visible spectroscopy, zeta potential, Fourier transform infra-red spectroscopy (FTIR, X-ray diffraction, Transmission electron microscopy (TEM analysis, Energy dispersive X-ray analysis (EDX and selected area electron diffraction (SAED pattern. UV–visible spectrum of synthesized silver nanoparticles showed maximum peak at 430 nm. TEM analysis revealed that the particles were spherical, hexagonal and irregular in shape and size ranging from 10 to 90 nm and Energy dispersive X-ray (EDX spectrum confirmed the presence of silver metal. Synergistic antimicrobial potential of silver nanoparticles was evaluated with various commercial antibiotics against Gram positive (Staphylococcus aureus and Bacillus cereus, Gram negative (Escherichia coli and Pseudomonas aeruginosa bacteria and fungi (Candida glabrata, Candida albicans, Cryptococcae neoformans. The antifungal activity of AgNPs with antibiotics was better than antibiotics alone against the tested fungal strains and Gram negative bacteria, thus signification of the present study is in production of biomedical products.

Silver release from coated particle fuel

International Nuclear Information System (INIS)

Brown, P.E.; Nabielek, H.

1977-03-01

The fission product Ag-110 m released from coated particles can be the dominant source of radioactivity from the core of a high temperature reactor in the early stages of the reactor life and possibly limits the accessability of primary circuit components. It can be shown that silver is retained in oxide fuel by a diffusion process (but not in carbide or carbon-diluted fuel) and that silver is released through all types of pyrocarbon layers. The retention in TRISO particles is variable and seems to be mainly connected with operating temperature and silicon carbide quality. (orig.) [de

国内外银镜还原剂对比试验%Comparative Trial of Reducing Agent for Silver-mirror Production at Home and Abroad

Institute of Scientific and Technical Information of China (English)

杨晨; 徐卫民; 梁中生

2011-01-01

Comparative trial of percent silver-conversion with home and abroad reducing agent was carried out on automatic silver-coating line under identical production parameters . The silver content on unit area was determined by titration and the conversion rate of silver nitrate with different reducing agent was evaluated.%在各项工艺参数基本相同的情况下，将国内外银镜还原剂在自动化镀银生产线上进行了银转化率对比试验，用滴定法测定镜子单位面积银的含量，分析了还原剂对硝酸银的转化率，结果表明，德国还原剂对银的转换效率为813％，英国还原剂对银的转换效率为70．8％。

A case of generalized argyria after ingestion of colloidal silver solution.

Science.gov (United States)

Kim, Yangho; Suh, Ho Seok; Cha, Hee Jeong; Kim, Suk Hwan; Jeong, Kyoung Sook; Kim, Dong Hoon

2009-03-01

A 58-year-old woman was referred to our hospital due to progressive skin darkening, which began 5 months previously. The patient had strikingly diffuse blue-gray discoloration of the skin, most prominent in sun-exposed areas, especially her face and hands. The oral mucosa, tongue, gums, eye conjunctiva, ears, nail beds, and trunk were also involved. Bluish-gray discoloration of all nails was aggravated by cold weather. She had ingested 1 L of colloidal silver solution daily for approximately 16 months as a traditional remedy. Her serum silver concentration was 381 ng/ml which was a very high (reference level: silver and sulfur in the dense black deposits. The ingestion of colloidal silver appears to be an increasing practice among patients using alternative health practices. All silver-containing products including colloidal silver should be labeled with a clear warning to prevent argyria, especially in alternative health practices.

Silver recovery from the waste materials by the method of flotation process

OpenAIRE

B. Oleksiak; G. Siwiec; A. Tomaszewska; D. Piękoś

2018-01-01

During the leaching process of zinc concentrates, the waste materials rich in various metals such as eg. silver are produced. So far no attempts of silver recovery from the mentioned waste materials have been made due to the lack of any method which would be both effective and beneficial. The paper presents some possibilities of application of flotation process in silver recovery form waste materials generated during zinc production.

In vitro cytotoxity of silver: implication for clinical wound care.

Science.gov (United States)

Poon, Vincent K M; Burd, Andrew

2004-03-01

In this study, we look at the cytotoxic effects of silver on keratinocytes and fibroblasts. We have assessed the viability of monolayer cultures using the MTT and BrdU assays. The composition of the culture medium and also the culture technique were modified to assess the effects of culture 'environment' on the susceptibility of the cells to the toxic action of silver. Further in vitro, experiments were performed using tissue culture models to allow cellular behavior in three dimensional planes which more closely simulated in vivo behavior. The silver source was both silver released from silver nitrate solution but also nanocrystalline silver released from a commercially available dressing. The results show that silver is highly toxic to both keratinocytes and fibroblasts in monolayer culture. When using optimized and individualized culture the fibroblasts appear to be more sensitive to silver than keratinocytes. However, when both cell types were grown in the same medium their viability was the same. Using tissue culture models again indicated an 'environmental effect' with decreased sensitivity of the cells to the cytotoxic effects of the silver. Nevertheless in these studies the toxic dose of skin cells ranging from 7 x 10(-4) to 55 x 10(-4)% was similar to that of bacteria. These results suggest that consideration of the cytotoxic effects of silver and silver-based products should be taken when deciding on dressings for specific wound care strategies. This is important when using keratinocyte culture, in situ, which is playing an increasing role in contemporary wound and burn care.

Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

Energy Technology Data Exchange (ETDEWEB)

Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi, E-mail: yangdz@mail.buct.edu.cn

2015-06-01

The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO{sub 3} aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi.

Development kinetics of silver clusters on silver halides

International Nuclear Information System (INIS)

Grzesiak, S.; Belloni, J.; Marignier, J.-L.

2008-01-01

Silver nuclei are produced by pulse radiolysis at the surface of AgCl nanocrystallites in the presence of an electron donor, the methyl viologen, which induces the growth of silver nuclei. The experimental results observed on the increase of the silver atom concentration and on the decay of the donor concentration during this process, which is similar to the photographic development by an electron donor, are compared with the kinetics obtained from numerical simulation. The model assumes that the formation of silver clusters with a supercritical nuclearity is required before the start of an electron transfer reaction from the two reduced forms of the donor methyl viologen to the silver clusters. The reaction is controlled by the access of the donor to the surface sites of the AgCl crystallite. The rate constant values of the successive steps of the mechanism are derived from the adjustment of calculated kinetics to experimental signals under various conditions, using a single set of parameters which are fairly suitable under all conditions studied

Silver removal from aqueous solution by biochar produced from biosolids via microwave pyrolysis.

Science.gov (United States)

Antunes, Elsa; Jacob, Mohan V; Brodie, Graham; Schneider, Philip A

2017-12-01

The contamination of water with silver has increased due to the widespread applications of products with silver employed as antimicrobial agent. Adsorption is a cost-effective method for silver removal from aqueous solution. In this study biochar, produced from the microwave assisted pyrolysis of biosolids, was used for silver removal from an aqueous solution. The adsorption kinetics, isotherms and thermodynamics were investigated to better understand the silver removal process by biochar. X-ray diffraction results demonstrated that silver removal was a combination two consecutive mechanisms, reduction and physical adsorption. The Langmuir model fitted the experimental data well, showing that silver removal was predominantly a surface mechanism. The thermodynamic investigation demonstrated that silver removal by biochar was an exothermic process. The final nanocomposite Ag-biochar (biochar plus silver) was used for methylene blue adsorption and photodegradation. This study showed the potential of using biochar produced from biosolids for silver removal as a promising solution to mitigate water pollution and an environmentally sustainable approach for biosolids management and re-use. Copyright © 2017 Elsevier Ltd. All rights reserved.

Russell-Silver syndrome

Science.gov (United States)

Silver-Russell syndrome; Silver syndrome; RSS; Russell-Silver syndrome ... One in 10 children with this syndrome has a problem involving chromosome 7. In other people with the syndrome, it may affect chromosome 11. Most of the time, it ...

Complexes of silver(I) ions and silver phosphate nanoparticles with hyaluronic acid and/or chitosan as promising antimicrobial agents for vascular grafts.

Science.gov (United States)

Chudobova, Dagmar; Nejdl, Lukas; Gumulec, Jaromir; Krystofova, Olga; Rodrigo, Miguel Angel Merlos; Kynicky, Jindrich; Ruttkay-Nedecky, Branislav; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

2013-06-28

Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes.

The immunomodulatory effects of titanium dioxide and silver nanoparticles.

Science.gov (United States)

Lappas, Courtney M

2015-11-01

Due to their characteristic physical, chemical and optical properties, titanium dioxide and silver nanoparticles are attractive tools for use in a wide range of applications. The use of nanoparticles for biological applications is, however, dependent upon their biocompatibility with living cells. Because of the importance of inflammation as a modulator of human health, the safe and efficacious in vivo use of titanium dioxide and silver nanoparticles is inherently linked to a favorable interaction with immune system cells. However, both titanium dioxide and silver nanoparticles have demonstrated potential to exert immunomodulatory and immunotoxic effects. Titanium dioxide and silver nanoparticles are readily internalized by immune system cells, may accumulate in peripheral lymphoid organs, and can influence multiple manifestations of immune cell activity. Although the factors influencing the biocompatibility of titanium dioxide and silver nanoparticles with immune system cells have not been fully elucidated, nanoparticle core composition, size, concentration and the duration of cell exposure seem to be important. Because titanium dioxide and silver nanoparticles are widely utilized in pharmaceutical, commercial and industrial products, it is vital that their effects on human health and immune system function be more thoroughly evaluated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Green synthesis of silver nanoparticles and biopolymer ...

Indian Academy of Sciences (India)

2018-03-29

Mar 29, 2018 ... Keywords. Biogenic silver nanoparticles; biopolymer nanocomposites; nanoparticles stability; ... Production of nanomaterials by using living organisms of plant-based ... 2.1b Microorganisms and cell culture: The evaluation of.

Charcoal as a capture material for silver nanoparticles in the aquatic environment

Science.gov (United States)

McGillicuddy, Eoin; Morrison, Liam; Cormican, Martin; Morris, Dearbháile

2017-04-01

Background: The reported antibacterial activity of silver nanoparticles (AgNPs) has led to their incorporation into numerous consumer products including; textiles, domestic appliances, food containers, cosmetics, paints, medical and medicinal products. The AgNPs incorporated into these products can be released into the environment and aquatic system during their production, use and end of life disposal. In the aquatic environment, uncertainties surround the concentration, fate and effects of AgNPs. The aim of this project is to examine charcoal as a potential material for capture of silver nanoparticles from the aquatic environment. Material/methods: Activated charcoal is a commonly used filter material and was selected for this project to determine its suitability as a capture material for AgNPs in water samples. Activated charcoal (Norit® CA1 (Sigma-Aldrich)) was exposed to 100 ppb, 25 nm PVP coated AgNPs (nanoComposix) prepared in Milli-Q water. These solutions were exposed to unaltered charcoal granules for 20 hours after which the decrease of silver in the solution was measured using ICP-MS. In order to improve the removal, the surface area of the charcoal was increased firstly by grinding with a pestle and mortar and secondly by milling the charcoal. The milled charcoal was prepared using an agate ball mill running at 500 rpm for 5 minutes. The activated charcoal was then exposed to samples containing 10 ppb AgNPs. Results: In the initial tests, approximately 10% of the silver was removed from the water samples using the unaltered activated charcoal granules. Further experiments were carried out to compare the unaltered granules with the ground and milled charcoal. These tests were carried out similarly to the previous test however lower concentration of 10 ppb was used. After 20 hours of exposure the granule samples, as previously, showed approximately a 10% reduction in silver content with the ground charcoal giving approximately 30% reduction in silver

Silver matrix composites reinforced with galvanically silvered particles

OpenAIRE

J. Śleziona; J. Wieczorek,

2007-01-01

Purpose: The paper presents the possibility of the application of metalic layers drifted with the use of the galvanic methods on the ceramic particles surface. The application of the layers was aimed at obtaining the rewetting of the reinforcing particles with the liquid silver in the course of the producing of silver matrix composites with the use of mechanical stirring method. To enable introducing of the iron powder and glass carbon powder to liquid silver the solution of covering the powd...

Drug Production in Tertiary Health Institutions – Needs, Constraints ...

African Journals Online (AJOL)

The use of questionnaires was employed in the study covering all pharmacists in the pharmaceutical services department, pharmacy technicians and quality control technologist in the drug production unit of the hospital. It was unanimously agreed by the respondents that local drug production was necessary in tertiary ...

Characterization of silver nanoparticles synthesized using an endophytic fungus, Penicillium oxalicum having potential antimicrobial activity

Science.gov (United States)

Bhattacharjee, Sukla; Debnath, Gopal; Das, Aparajita Roy; Krishna Saha, Ajay; Das, Panna

2017-12-01

The aim of the present study was to test the efficacy of the extracellular mycelium extract of Penicillium oxalicum isolated from Phlogacanthus thyrsiflorus to biosynthesize silver nanoparticles. It was characterized using ultraviolet-visible absorption spectroscopy, atomic force microscopy, transmission electron microscopy and Fourier transforms infrared spectroscopy. The silver nanoparticles were evaluated for antimicrobial activity. The characterization confirms the synthesis of silver nanoparticles. Both silver nanoparticles and combination of silver nanoparticles with streptomycin showed activity against the four bacteria. The results suggested that P. oxalicum offers eco-friendly production of silver nanoparticles and the antibacterial activity may find application in biomedicine.

Transporter-mediated natural product-drug interactions for the treatment of cardiovascular diseases.

Science.gov (United States)

Zha, Weibin

2018-04-01

The growing use of natural products in cardiovascular (CV) patients has been greatly raising the concerns about potential natural product-CV drug interactions. Some of these may lead to unexpected cardiovascular adverse effects and it is, therefore, essential to identify or predict potential natural product-CV drug interactions, and to understand the underlying mechanisms. Drug transporters are important determinants for the pharmacokinetics of drugs and alterations of drug transport has been recognized as one of the major causes of natural product-drug interactions. In last two decades, many CV drugs (e.g., angiotensin II receptor blockers, beta-blockers and statins) have been identified to be substrates and inhibitors of the solute carrier (SLC) transporters and the ATP-binding cassette (ABC) transporters, which are two major transporter superfamilies. Meanwhile, in vitro and in vivo studies indicate that a growing number of natural products showed cardioprotective effects (e.g., gingko biloba, danshen and their active ingredients) are also substrates and inhibitors of drug transporters. Thus, to understand transporter-mediated natural product-CV drug interactions is important and some transporter-mediated interactions have already shown to have clinical relevance. In this review, we review the current knowledge on the role of ABC and SLC transporters in CV therapy, as well as transporter modulation by natural products used in CV diseases and their induced natural product-CV drug interactions through alterations of drug transport. We hope our review will aid in a comprehensive summary of transporter-mediated natural product-CV drug interactions and help public and physicians understand these type of interactions. Copyright © 2017. Published by Elsevier B.V.

In vitro human digestion test to monitor the dissolution of silver nanoparticles

International Nuclear Information System (INIS)

Bove, P; Sabella, S; Malvindi, M A

2017-01-01

Nanotechnology is a scientific revolution that the food industry has experienced over the last years. Widely employed as food additives and/or food contact materials in consumer products, silver nanoparticles are an example of this innovation. However, their increasing use makes also likely the human ingestion, thus requiring a proper risk analysis. In this framework, a comprehensive characterization of biotransformation of silver nanoparticles in biological fluids is fundamental for the regulatory needs. Herein, we aimed at studying the dissolution behaviour of silver nanoparticles using an in vitro test, which simulates the human oral ingestion of NPs during their passage through the gastrointestinal tract. The nanoparticle suspensions were characterized in the different digestion phases using several techniques to follow the changes of key physical properties ( e.g. , size, surface charge and plasmon peak) and to quantify the biotransformed products arisen by the process, as for example free silver ions. (paper)

Silver recovery from the waste materials by the method of flotation process

Directory of Open Access Journals (Sweden)

B. Oleksiak

2018-01-01

Full Text Available During the leaching process of zinc concentrates, the waste materials rich in various metals such as eg. silver are produced. So far no attempts of silver recovery from the mentioned waste materials have been made due to the lack of any method which would be both effective and beneficial. The paper presents some possibilities of application of flotation process in silver recovery form waste materials generated during zinc production.

One-step microwave-assisted colloidal synthesis of hybrid silver oxide/silver nanoparticles: characterization and catalytic study

Science.gov (United States)

Prakoso, S. P.; Taufik, A.; Saleh, R.

2017-04-01

This study reports the characterization and catalytic activities of silver-oxide/silver nanoparticles (Ag2O/Ag NPs) synthesized by microwave-assisted colloidal method in the presence of anionic sodium dodecyl sulfate (SDS) surfactant. To promote different contents of silver in silver oxide, the volume ratio (VR) of ethylene glycol (EG) was varied (VR: 10% to 14%) in relation to the total volume of distilled water solvent. The plasmonic resonance of Ag2O/Ag NPs could be detected around a wavelength of 350 nm, and it is suggested that Ag2O/Ag NPs were successfully formed in the colloid solution following exposure to microwaves. Additionally, the growth rate for each crystal phase within Ag2O and Ag was influenced by an increase of EG as revealed by x-ray diffraction patterns. The morphology, average diameter, and uniformity of Ag2O/Ag NPs were studied simultaneously by transmission electron microscopy. Infrared absorption measurement of Ag2O/Ag NPs confirmed the existence of SDS surfactant as a protective agent. Based on the characterization data, Ag2O/Ag NPs synthesized using this technique exhibited good properties, with high-yield production of NPs. The photocatalytic experiments demonstrate the key role of the crystal phase of Ag2O/Ag NPs in photocatalytic efficiency.

Photochemical Study of Silver Nanoparticles Formed from the Reduction of Silver Ions by Humic Acid

Science.gov (United States)

Leslie, Renee M.

This study focuses on the ability of silver ions and humic acid to form silver nanoparticles in the presence of UV and visible light. Silver nanoparticles have a number of industrial applications due primarily to their antimicrobial properties, but these properties pose an environmental threat. Silver nanoparticles can directly disrupt sensitive ecosystems by harming bacteria. Consumption of silver nanoparticles results in silver ions and silver nanoparticles entering waterways; the presence of silver ions raises the question of whether nanoparticles can reform in environmental waters. As our data show, silver nanoparticles can form from the reduction of silver ions by humic acid after irradiation with UV and visible light. In order to better understand the mechanism of these naturally synthesized silver nanoparticles, we investigated the effects of reactant concentration, experimental conditions and presence of ions/reactive species. We monitored silver nanoparticle growth with UV-visible spectroscopy. The evolution in time of nanoparticle size was monitored by dynamic light scattering (DLS).

Production of drug nanosuspensions: effect of drug physical properties on nanosizing efficiency.

Science.gov (United States)

Liu, Tao; Müller, Rainer H; Möschwitzer, Jan P

2018-02-01

Drug nanosuspension is one of the established methods to improve the bioavailability of poorly soluble drugs. Drug physical properties aspect (morphology, solid state, starting size et al) is a critical parameter determining the production efficiency. Some drug modification approaches such as spray-drying were proved to improve the millability of drug powders. However, the mechanism behind those improved performances is unclear. This study is to systematically investigate the influence of those physical properties. Five different APIs (active pharmaceutical ingredients) with different millabilities, i.e. resveratrol, hesperetin, glibenclamide, rutin, and quercetin, were processed by standard high pressure homogenization (HPH), wet bead milling (WBM), and a combinative method of spray-drying and HPH. Smaller starting sizes of certain APIs could accelerate the particle size reduction velocity during both HPH and WBM processes. Spherical particles were observed for almost all spray-dried powders (except spray-dried hesperetin) after spray-drying. The crystallinity of some spray-dried samples such as rutin and glibenclamide became much lower than their corresponding unmodified powders. Almost all spray-dried drug powders after HPH processes could lead to smaller nanocrystal particle size than unmodified APIs. The modified microstructure instead of solid state after spray-drying explained the potential reason for improved nanosizing efficiency. In addition, the contribution of starting size on the production efficiency was also critical according to both HPH and WBM results.

Biosynthesis of silver nanoparticle and its application in cell wall disruption to release carbohydrate and lipid from C. vulgaris for biofuel production

Directory of Open Access Journals (Sweden)

Sirajunnisa Abdul Razack

2016-09-01

Full Text Available Microalgae are the fledging feedstocks yielding raw materials for the production of third generation biofuel. Assorted and conventional cell wall disruption techniques were helpful in extracting lipids and carbohydrates, nevertheless the disadvantages have led the biotechnologists to explore new process to lyse cell wall in a faster and an economical manner. Silver nanoparticles have the ability to break the cell wall of microalgae and release biomolecules effectively. Green synthesis of silver nanoparticles was performed using a novel bacterial isolate of Bacillus subtilis. Characterisation of nanosilver and its effect on cell wall lysis of microalgae were extensively analysed. Cell wall damage was confirmed by lactate dehydrogenase assay and visually by SEM analysis. This first piece of research work on direct use of nanoparticles for cell wall lysis would potentially be advantageous over its conventional approaches and a greener, cost effective and non laborious method for the production of biodiesel.

Visualization of silver-decorated poly (DL-lactide-co-glycolide) nanoparticles and their efficacy against Staphylococcus epidermidis

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Chisato, E-mail: chisato@dpc.agu.ac.jp [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan); Matsubara, Nobuhiro; Akachi, Yuki; Ogawa, Noriko [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan); Kalita, Golap [Department of Frontier Materials, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Asaka, Toru [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Tanemura, Masaki [Department of Frontier Materials, Nagoya Institute of Technology, Gokisocho, Showa-ku, Nagoya 466-8555 (Japan); Kawashima, Yoshiaki; Yamamoto, Hiromitsu [Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, 1-100, Kusumoto-cho, Chikusa-ku, Nagoya 464-8650 (Japan)

2017-03-01

Understanding of self-protection activity of the bacteria and interaction with drug substances has significant importance for designing of effective drug delivery system for treatment of biofilm infections. Recently silver nanoparticle has attracted attention as antibacterial substance for drug delivery system because of its high antibacterial activity. Here, efflux of silver nanoparticles obtained from within the prepared silver-decorated poly (DL-lactide-co-glycolide) (Ag PLGA) nanoparticles derived from Staphylococcus epidermidis bacterial cell was successfully visualized using scanning transmission electron microscopy (STEM). We also revealed the interaction between prepared Ag PLGA nanoparticles and the bacterial cells at the nanoscale level using field emission scanning electron microscopy and STEM, after a pretreatment process by an ionic liquid. This finding is significant to understand a fundamental function of S. epidermidis bacterial cells, which is not explored previously. The results suggest that Ag PLGA nanoparticles could demonstrate high efficacy against biofilm infections. - Highlights: • Ag PLGA nanoparticles with high efficacy against biofilm infections were prepared. • Self-protection activity of bacteria against Ag nanoparticles was visualized by STEM. • Antibacterial mechanism of Ag PLGA nanoparticles against biofilm was proposed.

Toward a generic approach for : Stress testing of drug substances and drug products

NARCIS (Netherlands)

Klick, Silke; Muijselaar, Pim G.; Waterval, Joop; Eichinger, Thomas; Korn, Christian; Gerding, Thijs K.; Debets, Alexander J.; Sänger-Van De Griend, Cari; Van Den Beld, Cas; Somsen, Govert W.; De Jong, Gerhardus J.

The Impurity Profiling Group has developed a generic approach for conducting stress testing on drug substances and drug products. The proposed strategy is evaluated and verified with historical data and new experiments. Results demonstrate that the proposed approach is reasonable and generates

Kinetics of silver release from microfuel with taking into account the limited-solubility effect

Science.gov (United States)

Ivanov, A. S.; Rusinkevich, A. A.

2014-12-01

The effect of a limited solubility of silver in silicon carbide on silver release from a microfuel with a TRISO coating is studied. It is shown that a limited solubility affects substantially both concentration profiles and silver release from a microfuel over a broad range of temperatures. A procedure is developed for obtaining fission-product concentration profiles in a microfuel and graphs representing the flow and integrated release of fission products on the basis of data from neutron-physics calculations and results obtained by calculating thermodynamics with the aid of the Ivtanthermo code and kinetics with the aid of the FP-Kinetics code. This procedure takes into account a limited solubility of fission products in protective coatings of microfuel.

Formation of novel assembled silver nanostructures from polyglycol solution

International Nuclear Information System (INIS)

Zhang Jie; Liu Ke; Dai Zhihui; Feng Yuying; Bao Jianchun; Mo Xiangyin

2006-01-01

This paper described a simple and mild chemical reduction approach to prepare novel silver nanostructures with different morphologies. Dendritic silver nanostructure was obtained by a fast reduction reaction using hydrazine as a reducing agent in aqueous solution of polyglycol, while both the zigzag and linear Ag nanostructures were slowly assembled using polyglycol as a reducing agent. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and field emission scanning electron microscopy (FE-SEM) were used to characterize the obtained silver nanostructures. Fourier transform infrared absorption (FT-IR) spectra were recorded to show that there exists a certain coordination of the oxygen atoms in the polyglycol with Ag + ions in aqueous solution of the AgNO 3 /polyglycol. Furthermore, the examination of the morphologies of the products obtained at different stages of the reaction of Ag + ions with polyglycol revealed that such a coordination is of utmost importance for the formation of the silver nanostructures, namely polyglycol provided lots of active sites for the coordination, nucleation, growth and serves as backbones for directing the assembly of the metal particles formed. The formation mechanism of the dendritic silver nanostructure was called a coordination-reduction-nucleation-growth-fractal growth process. The strong surface plasmon absorption bands at 470 nm for the zigzag silver and at 405 nm for the dendritic silver were found

Ergonomic Synthesis Suitable for Industrial Production of Silver-Festooned Zinc Oxide Nanorods

Science.gov (United States)

Khan, G. R.; Khan, R. A.

2015-07-01

For maximizing productivity, minimizing cost, time-boxing process and optimizing human effort, a single-step, cost-effective, ultra-fast and environmentally benign synthesis suitable for industrial production of nanocrystalline ZnO, and Ag-doped ZnO has been reported in this paper. The synthesis based on microwave-supported aqueous solution method used zinc acetate dehydrate and silver nitrate as precursors for fabrication of nanorods. The synthesized products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and UV-Vis-NIR spectroscopy. The undoped and Ag-doped ZnO nanorods crystallized in a hexagonal wurtzite structure having spindle-like morphology. The blue shift occurred at absorption edge of Ag-doped ZnO around 260 nm compared to 365 nm of bulk ZnO. The red shift occurred at Raman peak site of 434 cm-1 compared to characteristic wurtzite phase peak of ZnO (437 cm-1). The bandgap energies were found to be 3.10 eV, 3.11 eV and 3.18 eV for undoped, 1% Ag-doped, and 3% Ag-doped ZnO samples, respectively. The TEM results provided average particle sizes of 17 nm, 15 nm and 13 nm for undoped, and 1% and 3% Ag-doped ZnO samples, respectively.

Silver Flakes and Silver Dendrites for Hybrid Electrically Conductive Adhesives with Enhanced Conductivity

Science.gov (United States)

Ma, Hongru; Li, Zhuo; Tian, Xun; Yan, Shaocun; Li, Zhe; Guo, Xuhong; Ma, Yanqing; Ma, Lei

2018-03-01

Silver dendrites were prepared by a facile replacement reaction between silver nitrate and zinc microparticles of 20 μm in size. The influence of reactant molar ratio, reaction solution volume, silver nitrate concentration, and reaction time on the morphology of dendrites was investigated systematically. It was found that uniform tree-like silver structures are synthesized under the optimal conditions. Their structure can be described as a trunk, symmetrical branches, and leaves, which length scales of 5-10, 1-2 μm, and 100-300 nm, respectively. All features were systematically characterized by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, and x-ray powder diffraction. A hybrid fillers system using silver flakes and dendrites as electrically conductive adhesives (ECAs) exhibited excellent overall performance. This good conductivity can be attributed mainly to the synergy between the silver microflakes (5-20 μm sized irregular sheet structures) and dendrites, allowing more conductive pathways to be formed between the fillers. In order to further optimize the overall electrical conductivity, various mixtures of silver microflakes and silver dendrites were tested in ECAs, with results indicating that the highest conductivity was shown when the amounts of silver microflakes, silver dendrites and the polymer matrix were 69.4 wt.% (20.82 vol.%), 0.6 wt.% (0.18 vol.%), and 30.0 wt.% (79.00 vol.%), respectively. The corresponding mass ratio of silver flakes to silver dendrites was 347:3. The resistivity of ECAs reached as low as 1.7 × 10-4 Ω cm.

Optimization for extracellular biosynthesis of silver nanoparticles by Penicillium aculeatum Su1 and their antimicrobial activity and cytotoxic effect compared with silver ions.

Science.gov (United States)

Ma, Liang; Su, Wei; Liu, Jian-Xin; Zeng, Xiao-Xi; Huang, Zhi; Li, Wen; Liu, Zheng-Chun; Tang, Jian-Xin

2017-08-01

The present study addresses an eco-friendly and energy-saving method for extracellular biosynthesis of silver nanoparticles (AgNPs) using a cell free filtrate of the fungus strain Penicillium aculeatum Su1 as a reducing agent. Parametric optimization of the biosynthesis process demonstrated different effects on the size, distribution, yield, and synthesis rate of biosynthesized AgNPs. The transmission electron microscopy (TEM) measurements demonstrated that AgNPs were spherical or approximately spherical, with a size between 4 and 55nm. High-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD) analyses indicated that AgNPs were nanocrystalline by nature, with the character of a face-centered cubic (fcc). Fourier transform infrared spectroscopy (FTIR) analysis confirmed the existence of protein molecules that acted as a reducing agent and a capping agent during the biosynthesis process. Furthermore, the biosynthesized AgNPs exhibited higher antimicrobial activity than silver ions against Gram negative bacteria, Gram positive bacteria and fungi. Compared with silver ions, the biosynthesized AgNPs presented higher biocompatibility toward human bronchial epithelial (HBE) cells and high cytotoxicity in a dose-dependent manner with an IC 50 of 48.73μg/mL toward A549 cells. These results demonstrate that Penicillium aculeatum Su1 is a potential bioresource that can be used to produce low-cost and eco-friendly AgNPs as efficient antimicrobial agent, drug delivery vehicle or anticancer drug for clinic treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

USE OF SILVER IONS IN PASTEURIZED MILK PRODUCTION

OpenAIRE

A. Mamaev; K. Leshukov; S. Stepanova

2012-01-01

The means of pasteurized milk shelf life prolongation by electro-chemical diffusion of silver ions has been introduced. Three samples of pasteurized milk were test subjects. In the course of study the following data have been examined: organoleptic, physicochemical, microbiological parameters of check samples and pilot samples of raw and pasteurized milk. Its shelf life has been determined. It has been determined that the test results of raw and pasteurized milk samples processed by various c...

Synthesis of silver nanoparticles in hydrogels crosslinked by ionizing radiation

International Nuclear Information System (INIS)

Alcantara, Maria Tania S.; Oliani, Washington L.; Brant, Antonio J.C.; Oliveira, Maria Jose A. de; Riella, Humberto Gracher; Lugao, Ademar B.

2013-01-01

Hydrogel is defined as a polymeric material which exhibits the ability to swell and retain a significant fraction of water within its structure without dissolving the polymeric network. Silver nanoparticles (AgNPs) are used in a range of medicinal products based on hydrogels and diverse other products due to their antibacterial properties at low concentrations. The use of ionizing radiation in the production process of hydrogels of poly(N-vinyl-2-pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) in aqueous solutions enables the crosslinking of their polymer chains. If polymer solutions contain Ag + ions, these can be reduced radiolytically to nanocrystalline silver. The objective of this study was to investigate the reduction of Ag + ions by gamma-irradiation for the synthesis of AgNPs in hydrogels of PVA and PVP as main polymers and to make a comparison of the performance of the two polymeric matrices, chiefly focusing on the effect of the AgNPs' synthesis on the crosslinking of both polymers. The properties of the hydrogel matrices obtained were evaluated from tests of gel fraction, swelling in water, and stress-strain. The results of mechanical properties of PVA matrix were higher than those of PVP one whereas the latter exhibited a higher swelling degree. The reduction of silver ions was confirmed by UV-visible absorption spectrum, whose characteristics also indicated the formation of silver nanoparticles in both arrays. (author)

Recreational drug discovery: natural products as lead structures for the synthesis of smart drugs.

Science.gov (United States)

Appendino, Giovanni; Minassi, Alberto; Taglialatela-Scafati, Orazio

2014-07-01

Covering: up to December 2013. Over the past decade, there has been a growing transition in recreational drugs from natural materials (marijuana, hashish, opium), natural products (morphine, cocaine), or their simple derivatives (heroin), to synthetic agents more potent than their natural prototypes, which are sometimes less harmful in the short term, or that combine properties from different classes of recreational prototypes. These agents have been named smart drugs, and have become popular both for personal consumption and for collective intoxication at rave parties. The reasons for this transition are varied, but are mainly regulatory and commercial. New analogues of known illegal intoxicants are invisible to most forensic detection techniques, while the alleged natural status and the lack of avert acute toxicity make them appealing to a wide range of users. On the other hand, the advent of the internet has made possible the quick dispersal of information among users and the on-line purchase of these agents and/or the precursors for their synthesis. Unlike their natural products chemotypes (ephedrine, mescaline, cathinone, psilocybin, THC), most new drugs of abuse are largely unfamiliar to the organic chemistry community as well as to health care providers. To raise awareness of the growing plague of smart drugs we have surveyed, in a medicinal chemistry fashion, their development from natural products leads, their current methods of production, and the role that clandestine home laboratories and underground chemists have played in the surge of popularity of these drugs.

21 CFR 250.250 - Hexachlorophene, as a component of drug and cosmetic products.

Science.gov (United States)

2010-04-01

... cosmetic products. 250.250 Section 250.250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Requirements for Drugs and Cosmetics § 250.250 Hexachlorophene, as a component of drug and cosmetic products... cosmetic products has expanded widely in recent years. It is used in such products because of its...

Potential for photocatalytic degradation of the potassic diclofenac using scandium and silver modified titanium dioxide thin films

International Nuclear Information System (INIS)

Ciola, R.A.; Oliveira, C.T.; Lopes, S.A.; Cavalheiro, A.A.

2011-01-01

The potential for photocatalytic degradation of the potassic diclofenac drug was investigated using titanium dioxide thin films modified with two modifier types, scandium and silver, both prepared by Sol-Gel method. It was demonstrated by UVVis spectroscopy analysis of the solutions containing the drug, under UV-A light irradiation that the degradation efficiency of the titanium dioxide photocatalyst is dependent of the semiconductor nature and that the scandium accelerates the first step of the degradation when compared to the silver. This result seems to be related to the redox potential of the electron-hole pair, once the scandium modifying sample generates a p type semiconductor that reduces the band gap. The extra holes attract more strongly the chorine ion present in diclofenac and leading to the releasing more easily. However, after the first byproducts degradation the following steps are not facilitated, making the silver modifying more advantageous. (author)

Green synthesized silver nanoparticles destroy multidrug resistant bacteria via reactive oxygen species mediated membrane damage

Directory of Open Access Journals (Sweden)

Balaram Das

2017-09-01

Full Text Available The growing need of antimicrobial agent for novel therapies against multi-drug resistant bacteria has drawn researchers to green nanotechnology. Especially, eco-friendly biosynthesis of silver nanoparticles (Ag NPs has shown its interesting impact against bacterial infection in laboratory research. In this study, a simple method was developed to form Ag NPs at room temperature, bio-reduction of silver ions from silver nitrate salt by leaf extract from Ocimum gratissimum. The Ag NPs appear to be capped with plant proteins, but are otherwise highly crystalline and pure. The Ag NPs have a zeta potential of −15 mV, a hydrodynamic diameter of 31 nm with polydispersity index of 0.65, and dry sizes of 18 ± 3 nm and 16 ± 2 nm, based on scanning and transmission electron microscopy respectively. The minimum inhibitory concentration (MIC of the Ag NPs against a multi-drug resistant Escherichia coli was 4 μg/mL and the minimum bactericidal concentration (MBC was 8 μg/mL, while the MIC and MBC against a resistant strain of Staphylococcus aureus were slightly higher at 8 μg/mL and 16 μg/mL respectively. Further, the Ag NPs inhibited biofilm formation by both Escherichia coli and S. aureus at concentrations similar to the MIC for each strain. Treatment of E. coli and S. aureus with Ag NPs resulted in damage to the surface of the cells and the production of reactive oxygen species. Both mechanisms likely contribute to bacterial cell death. In summary, this new method appears promising for green biosynthesis of pure Ag NPs with potent antimicrobial activity.

Measurement of the isotope effect of the diffusion of silver and gold in gold and of silver in silver-gold alloys

International Nuclear Information System (INIS)

Wolter, D.

1974-01-01

The silver isotopes Ag 105 and Agsup(110m) and the gold isotopes Au 195 and Au 199 were used for isotope effect measurements. The isotope effect of the gold self-diffusion was measured on four monocrystals samples at about 850 0 C, that of silver in gold monocrystals at five different temperatures between 731 0 C and 1050 0 C. Furthermore, the isotope effect for silver at 904 0 C was measured on seven silver-gold alloys of varying silver concentration. The correlation factor was determined from the measurements. (HPOE/LH) [de

Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species

Science.gov (United States)

Pourshahid, Seyedmohammad; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

2016-01-01

Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM). There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity. PMID:27652264

Complex conductivity response to silver nanoparticles in ...

Science.gov (United States)

The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research needs include knowledge and methods for their detection, characterization, fate, and transport. Specifically, techniques available for the direct detection and quantification of their fate and transport in the environment are limited. Their small size, high surface area to volume ratio, interfacial, and electrical properties make metallic nanoparticles, such as silver nanoparticles, good targets for detection using electrical geophysical techniques. Here we measured the complex conductivity response to silver nanoparticles in sand columns under varying moisture conditions (0–30%), nanoparticle concentrations (0–10 mg/g), lithology (presence of clay), pore water salinity (0.0275 and 0.1000 S/m), and particle size (35, 90–210 and 1500–2500 nm). Based on the Cole-Cole relaxation models we obtained the chargeability and the time constant. We demonstrate that complex conductivity can detect silver nanoparticles in porous media with the response enhanced by higher concentrations of silver nanoparticles, moisture content, ionic strength, clay content and particle diameter. Quantification of the volumetric silver nanoparticles content in the porous media can also be obtained from complex co

Crystal structure of a mixed-ligand silver(I complex of the non-steroidal anti-inflammatory drug diclofenac and pyrimidine

Directory of Open Access Journals (Sweden)

Sevim Hamamci Alisir

2016-10-01

Full Text Available In the title mixed-ligand silver(I coordination polymeric complex with the non-steroidal anti-inflammatory drug diclofenac (C14H11Cl2NO2 (diclH and pyrimidine (pym, namely poly[{μ2-2-[2-(2,6-dichloroanilinophenyl]acetato-κ2O:O′}(μ2-pyrimidine-κ2N1:N3silver(I], [Ag(C14H10Cl2NO2(C4H4N2]n or [Ag(μ-dicl(μ-pym]n, the very distorted tetrahedral AgN2O2 coordination centres comprise two N-atom donors from bridging pym ligands [Ag—N = 2.381 (3 and 2.412 (3 Å] and two carboxylate O-atom donors from dicl ligands [Ag—O = 2.279 (2 and 2.280 (2 Å], which bridge Ag atoms, giving a centrosymmetric dinuclear units with a short Ag...Ag separation [2.8931 (5 Å]. Within the units are short intraligand C—Cl...π(pym interactions [3.6409 (15 Å]. The units are linked through the bridging N atoms of the pym ligand into a two-dimensional sheet–polymer structure lying parallel to (100 and stabilized by inter-ring π–π interactions between the pym ligands [Cg...Cg = 3.4199 (17 Å]. Additional inter-unit C—H...O and C—H...Cg hydrogen-bonding interactions between the sheets give an overall three-dimensional structure.

ATP7B detoxifies silver in ciliated airway epithelial cells

International Nuclear Information System (INIS)

Ibricevic, Aida; Brody, Steven L.; Youngs, Wiley J.; Cannon, Carolyn L.

2010-01-01

Silver is a centuries-old antibiotic agent currently used to treat infected burns. The sensitivity of a wide range of drug-resistant microorganisms to silver killing suggests that it may be useful for treating refractory lung infections. Toward this goal, we previously developed a methylated caffeine silver acetate compound, SCC1, that exhibits broad-spectrum antimicrobial activity against clinical strains of bacteria in vitro and when nebulized to lungs in mouse infection models. Preclinical testing of high concentrations of SCC1 in primary culture mouse tracheal epithelial cells (mTEC) showed selective ciliated cell death. Ciliated cell death was induced by both silver- and copper-containing compounds but not by the methylated caffeine portion of SCC1. We hypothesized that copper transporting P-type ATPases, ATP7A and ATP7B, play a role in silver detoxification in the airway. In mTEC, ATP7A was expressed in non-ciliated cells, whereas ATP7B was expressed only in ciliated cells. The exposure of mTEC to SCC1 induced the trafficking of ATP7B, but not ATP7A, suggesting the presence of a cell-specific silver uptake and detoxification mechanisms. Indeed, the expression of the copper uptake protein CTR1 was also restricted to ciliated cells. A role of ATP7B in silver detoxification was further substantiated when treatment of SCC1 significantly increased cell death in ATP7B shRNA-treated HepG2 cells. In addition, mTEC from ATP7B -/- mice showed enhanced loss of ciliated cells compared to wild type. These studies are the first to demonstrate a cell type-specific expression of the Ag + /Cu + transporters ATP7A, ATP7B, and CTR1 in airway epithelial cells and a role for ATP7B in detoxification of these metals in the lung.

78 FR 10265 - Pricing for the 2013 Commemorative Coin Programs-Silver and Clad Coin Options

Science.gov (United States)

2013-02-13

.... SUMMARY: The United States Mint is announcing prices for the 2013 Girl Scouts of the USA Centennial Silver.... Introductory Product price Regular price 2013 Girl Scouts of the USA Centennial $54.95 $59.95 Proof Silver Dollar 2013 Girl Scouts of the USA Centennial 50.95 55.95 Uncirculated Silver Dollar 2013 5-Star Generals...

Silver Nanoparticles: Synthetic Routes, In Vitro Toxicity and Theranostic Applications for Cancer Disease

Directory of Open Access Journals (Sweden)

Valeria De Matteis

2018-05-01

Full Text Available The large use of nanomaterials in many fields of application and commercial products highlights their potential toxicity on living organisms and the environment, despite their physico-chemical properties. Among these, silver nanoparticles (Ag NPs are involved in biomedical applications such as antibacterial agents, drug delivery vectors and theranostics agents. In this review, we explain the common synthesis routes of Ag NPs using physical, chemical, and biological methods, following their toxicity mechanism in cells. In particular, we analyzed the physiological cellular pathway perturbations in terms of oxidative stress induction, mitochondrial membrane potential alteration, cell death, apoptosis, DNA damage and cytokines secretion after Ag NPs exposure. In addition, their potential anti-cancer activity and theranostic applications are discussed.

Effect of methyl jasmonate and silver nanoparticles on production of ...

African Journals Online (AJOL)

Conclusion: Treatment of C. officinalis L. with SNPs and MeJA seems to be a simple and cost-effective method of improving the medicinal properties of this plant. Keywords: Calendula officinalis, Silver nanoparticles, Methyl jasmonate, Secondary metabolites, HeLa cells, Membrane lipid peroxidation, Radical scavenging ...

21 CFR 336.50 - Labeling of antiemetic drug products.

Science.gov (United States)

2010-04-01

... years of age. “Do not take this product, unless directed by a doctor, if you have a breathing problem... Section 336.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... under 12 years of age. “Do not give this product to children who have a breathing problem such as...

A green and facile approach for the synthesis of silver nanoparticles ...

Indian Academy of Sciences (India)

Silver nanoparticles possess a wide range of applications especially in the field ... Conventionally, chemical methods are used, which are hazardous and ... toxic byproducts, drastic reaction condition and difficulty ... ous herbal plants, viz., Piper longum,4 Piper nigram,5 and ... a local drug store in Chennai, Tamilnadu, India.

Synthesis, Characterization, and In Vivo Efficacy of Shell Cross-Linked Nanoparticle Formulations Carrying Silver Antimicrobials as Aerosolized Therapeutics

Science.gov (United States)

2014-01-01

The use of nebulizable, nanoparticle-based antimicrobial delivery systems can improve efficacy and reduce toxicity for treatment of multi-drug-resistant bacteria in the chronically infected lungs of cystic fibrosis patients. Nanoparticle vehicles are particularly useful for applying broad-spectrum silver-based antimicrobials, for instance, to improve the residence time of small-molecule silver carbene complexes (SCCs) within the lung. Therefore, we have synthesized multifunctional, shell cross-linked knedel-like polymeric nanoparticles (SCK NPs) and capitalized on the ability to independently load the shell and core with silver-based antimicrobial agents. We formulated three silver-loaded variants of SCK NPs: shell-loaded with silver cations, core-loaded with SCC10, and combined loading of shell silver cations and core SCC10. All three formulations provided a sustained delivery of silver over the course of at least 2–4 days. The two SCK NP formulations with SCC10 loaded in the core each exhibited excellent antimicrobial activity and efficacy in vivo in a mouse model of Pseudomonas aeruginosa pneumonia. SCK NPs with shell silver cation-load only, while efficacious in vitro, failed to demonstrate efficacy in vivo. However, a single dose of core SCC10-loaded SCK NPs (0.74 ± 0.16 mg Ag) provided a 28% survival advantage over sham treatment, and administration of two doses (0.88 mg Ag) improved survival to 60%. In contrast, a total of 14.5 mg of Ag+ delivered over 5 doses at 12 h intervals was necessary to achieve a 60% survival advantage with a free-drug (SCC1) formulation. Thus, SCK NPs show promise for clinical impact by greatly reducing antimicrobial dosage and dosing frequency, which could minimize toxicity and improve patient adherence. PMID:23718195

Highly efficient silver patterning without photo-resist using simple silver precursors

International Nuclear Information System (INIS)

Byun, Younghun; Hwang, Eoc-Chae; Lee, Sang-Yun; Lyu, Yi-Yeol; Yim, Jin-Heong; Kim, Jin-Young; Chang, Seok; Pu, Lyong Sun; Kim, Ji Man

2005-01-01

Highly efficient method for silver patterning without photo-resist was developed by using high photosensitive organo-silver precursors, which were prepared by a simple reaction of silver salts and excess of amines. The FT-IR and GC-MS spectra were recorded depending on UV exposure time, for (n-PrNH 2 )Ag(NO 3 ).0.5MeCN and (n-PrNH 2 )Ag(NO 2 ).0.5MeCN, to understand the photolysis mechanism. The results indicate not only dissociation of coordinated amine and acetonitrile, but also decomposition of corresponding anion upon UV irradiation. When a precursor thin film was exposed to broadband UV irradiation, a partially reduced and insoluble silver species were formed within several minutes. After development, the irradiated areas were treated with a reducing agent to obtain pure metallic patterns. Subsequently, annealing step was followed at 100-350 deg. C to increase the adhesion of interface and cohesion of silver particles. The line resolution of 5 μm was obtained by the present silver precursors. Film thickness was also controllable from 50 to 250 nm by repetition of the above procedure. The average electrical conductivity was in the range of 3-43 Ω cm, measured by four-point probe technique. AES depth profile of the silver pattern thus obtained showed carbon and oxygen contents are less than 1% through the whole range. Even though sulfur contaminant exists on the surface, it was believed that nearly pure silver pattern was generated

Isolation and identification of burn wound superbugs by molecular technique and their susceptibility to silver nanoparticles

Science.gov (United States)

Mala, R.; Celsia, A. S. Ruby

2018-02-01

Burn wound is a global problem affecting millions of people. It is the major cause of mortality and morbidity. This study was aimed to isolate and identify the wound isolates by 16S rRNA and to assess their susceptibility to antibiotics and silver nanoparticles. Silver nanoparticles were synthesized using aqueous extract of A.indica. The silver nanoparticles were characterized by FESEM, XRD, FTIR and DSC. Antibacterial susceptibility of the isolates was assessed by well diffusion method. The wound isolates were identified as S.aureus and E.coli. Both isolates were resistant to β lactum antibiotics, aminoglycoside, quinolones and macrolides. The inhibition zone exhibited by all antibiotics against both organisms was less than 5 mm. The size of silver nanoparticles were recorded as 55 nm. XRD confirmed the crystalline nature of the nanoparticles. TGA and DSC of silver nanoparticles showed the loss of weight and the melting point of silver nanoparticles was recorded at 871.3°C. Silver nano particles inhibited S.aureus and E.coli with an inhibition zone of 27 mm and 32 mm respectively. Therefore the study demonstrated that only silver containing dressings can be used in burn wounds infected by multi drug resistant super bugs.

Advances in Silver Nanotechnology: An Update on Biomedical Applications and Future Perspectives.

Science.gov (United States)

Aziz, Shiva Gholizadeh-Ghaleh; Aziz, Sara Gholizadeh-Ghaleh; Akbarzadeh, Abolfazl

2017-04-01

Nanotechnology is one of the most promising fields for producing new applications in nanotechnology, biotechnology, and medicine. However, only a few products have been used for nanotechnology, biotechnology, and medical purposes. Nanoparticles have been among the most usually applied nanomaterial in our health care system for hundreds of years. The most prominent nano product is nano silver which generally present at 1-100 nm in size in at least one dimension. Silver nanoparticles reveal remarkably unusual chemical, physical and biological properties and have been used for many different applications which detailed in this review. This review is focusing on the different form of silver nanoparticles and its nanotechnological, biotechnological and medical applications. © Georg Thieme Verlag KG Stuttgart · New York.

Evaluation of In-Use Stability of Anticoagulant Drug Products: Warfarin Sodium.

Science.gov (United States)

Nguyenpho, Agnes; Ciavarella, Anthony B; Siddiqui, Akhtar; Rahman, Ziyaur; Akhtar, Sohail; Hunt, Robert; Korang-Yeboah, Maxwell; Khan, Mansoor A

2015-12-01

The objective of the study was to evaluate the stability of warfarin products during use by patients or caregivers. For evaluation, three commercial products manufactured by different processes were selected and placed at 30°C/75%RH to simulate in use condition. Samples were withdrawn up to 12 weeks and analyzed for the physicochemical changes. Scanning electron microscopy demonstrated increasing holes and craters in the tablets over the timeframe. Near-infrared chemical imaging and powder X-ray powder diffraction corroborated the change arising from conversion of crystalline to amorphous forms of the drug. Hardness and disintegration time of the tablets were found to increase progressively. With increasing time, moisture contents of the products were found to increase and consequent decrease in isopropyl alcohol content of the product. Dissolution of the tablets in media at pH 4.5 demonstrated discrimination between crystalline and amorphous drug products. Overall, percent drug dissolved in each product at 30 min was found to decrease with increasing exposure time. Dissolution of drug decreased from 54% to 38% and 82% to 54% for the two products while the third product maintained consistently high level of dissolution. These results suggest that the drug product quality attributes can change during use. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors

Energy Technology Data Exchange (ETDEWEB)

Uznanski, Pawel, E-mail: puznansk@cbmm.lodz.pl; Zakrzewska, Joanna [Centre of Molecular and Macromolecular Studies, PAS (Poland); Favier, Frederic, E-mail: fredf@univ-montp2.fr [Université Montpellier II, ICGM - UMR5253- Equipe AIME (France); Kazmierski, Slawomir; Bryszewska, Ewa [Centre of Molecular and Macromolecular Studies, PAS (Poland)

2017-03-15

A comparative study of amine and silver carboxylate adducts [R{sub 1}COOAg-2(R{sub 2}NH{sub 2})] (R{sub 1} = 1, 7, 11; R{sub 2} = 8, 12) as a key intermediate in NPs synthesis is carried out via differential scanning calorimetry, solid-state FT-infrared spectroscopy, {sup 13}C CP MAS NMR, powder X-ray diffraction and X-ray photoelectron spectroscopy, and various solution NMR spectroscopies ({sup 1}H and {sup 13}C NMR, pulsed field gradient spin-echo NMR, and ROESY). It is proposed that carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination as opposed to bridging bidentate coordination of pure silver carboxylates resulting from the formation of dimeric units. All complexes are packed as lamellar bilayer structures. Silver carboxylate/amine complexes show one first-order melting transition. The evidence presented in this study shows that phase behavior of monovalent metal carboxylates are controlled, mainly, by head group bonding. In solution, insoluble silver salt is stabilized by amine molecules which exist in dynamic equilibrium. Using (bis)amine-silver carboxylate complex as precursor, silver nanoparticles were fabricated. During high-temperature thermolysis, the (bis)amine-carboxylate adduct decomposes to produce silver nanoparticles of small size. NPs are stabilized by strongly interacting carboxylate and trace amounts of amine derived from the silver precursor interacting with carboxylic acid. A corresponding aliphatic amide obtained from silver precursor at high-temperature reaction conditions is not taking part in the stabilization. Combining NMR techniques with FTIR, it was possible to follow an original stabilization mechanism.

Cell culture media impact on drug product solution stability.

Science.gov (United States)

Purdie, Jennifer L; Kowle, Ronald L; Langland, Amie L; Patel, Chetan N; Ouyang, Anli; Olson, Donald J

2016-07-08

To enable subcutaneous administration of monoclonal antibodies, drug product solutions are often needed at high concentrations. A significant risk associated with high drug product concentrations is an increase in aggregate level over the shelf-life dating period. While much work has been done to understand the impact of drug product formulation on aggregation, there is limited understanding of the link between cell culture process conditions and soluble aggregate growth in drug product. During cell culture process development, soluble aggregates are often measured at harvest using cell-free material purified by Protein A chromatography. In the work reported here, cell culture media components were evaluated with respect to their impact on aggregate levels in high concentration solution drug product during accelerated stability studies. Two components, cysteine and ferric ammonium citrate, were found to impact aggregate growth rates in our current media (version 1) leading to the development of new chemically defined media and concentrated feed formulations. The new version of media and associated concentrated feeds (version 2) were evaluated across four cell lines producing recombinant IgG4 monoclonal antibodies and a bispecific antibody. In all four cell lines, the version 2 media reduced aggregate growth over the course of a 12 week accelerated stability study compared with the version 1 media, although the degree to which aggregate growth decreased was cell line dependent. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:998-1008, 2016. © 2016 American Institute of Chemical Engineers.

21 CFR 349.65 - Labeling of ophthalmic emollient drug products.

Science.gov (United States)

2010-04-01

... product contains the established name of the drug(s), if any, and identifies the product as a “lubricant... the eye or to exposure to wind or sun.” (3) “For use as a protectant against further irritation or to...

21 CFR 349.60 - Labeling of ophthalmic demulcent drug products.

Science.gov (United States)

2010-04-01

... product contains the established name of the drug(s), if any, and identifies the product as a “lubricant... exposure to wind or sun.” (3) “For use as a protectant against further irritation or to relieve dryness of...

Photochemical Synthesis of Silver Nanodecahedrons and Related Nanostructures for Plasmonic Field Enhancement Applications

Science.gov (United States)

Lu, Haifei

Noble-metal nanocrystals have received considerable attention in recent years for their size and shape dependent localized surface Plasmon resonances (LSPR). Various applications based on colloidal nanoparticles, such as surface enhanced Raman scattering (SERS), surface enhanced fluorescence (SEF), plasmonic sensing, photothermal therapy etc., have been broadly explored in the field of biomedicine, because of their extremely large optical scattering and absorption cross sections, as well as giant electric field enhancement on their surface. However, despite its high chemical stability, gold exhibits quite large losses and electric field enhancement is comparatively weaker than silver. Silver nanoparticles synthesized by the traditional technique only cover an LSPR ranged from 420~500 nm. On the other hand, the range of 500~660 nm, which is covered by several easily available commercial laser lines, very limited colloidal silver nanostructures with controllable size and shape have been reported, and realization of tuning the resonance to longer wavelengths is very important for the practical applications. In this thesis, a systematic study on photochemical synthesis of silver nanodecahedrons (NDs) and related nanostructures, and their plasmonic field enhancements are presented. First, the roles of chemicals and the light source during the formation of silver nanoparticles have been studied. We have also developed a preparation route for the production size-controlled silver nanodecahedrons (LSPR range 420 ~ 660 nm) in high purity. Indeed our experiments indicate that both the chemicals and the light sources can affect the shape and purity of final products. Adjusting the molar ratio between sodium citrate and silver nitrate can help to control the crystal structure following rapid reduction from sodium borohydride. Light from a blue LED (465 nm) can efficiently transform the polyvinylpyrrolidone stabilized small silver nanoparticles into silver NDs through photo

Green Synthesis and Antibacterial Effect of Silver Nanoparticles Using Vitex Negundo L.

Directory of Open Access Journals (Sweden)

Fatima Abu Bakar

2011-08-01

Full Text Available Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs due to their multiple applications. One of the most important applications of Ag-NPs is their use as an anti-bacterial agent. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the biosynthesis of silver nanoparticles using Vitex negundo L. extract and its antimicrobial properties has been reported. The resulting silver particles are characterized using transmission electron microscopy (TEM, X-ray diffraction (XRD and UV–Visible (UV-Vis spectroscopic techniques. The TEM study showed the formation of silver nanoparticles in the 10–30 nm range and average 18.2 nm in size. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc structure. The silver nanoparticles showed the antimicrobial activity against Gram positive and Gram negative bacteria. Vitex negundo L. was found to display strong potential for the synthesis of silver nanoparticles as antimicrobial agents by rapid reduction of silver ions (Ag+ to Ag0.

Silver distribution and release from an antimicrobial denture base resin containing silver colloidal nanoparticles.

Science.gov (United States)

Monteiro, Douglas Roberto; Gorup, Luiz Fernando; Takamiya, Aline Satie; de Camargo, Emerson Rodrigues; Filho, Adhemar Colla Ruvolo; Barbosa, Debora Barros

2012-01-01

The aim of this study was to evaluate a denture base resin containing silver colloidal nanoparticles through morphological analysis to check the distribution and dispersion of these particles in the polymer and by testing the silver release in deionized water at different time periods. A Lucitone 550 denture resin was used, and silver nanoparticles were synthesized by reduction of silver nitrate with sodium citrate. The acrylic resin was prepared in accordance with the manufacturers' instructions, and silver nanoparticle suspension was added to the acrylic resin monomer in different concentrations (0.05, 0.5, and 5 vol% silver colloidal). Controls devoid of silver nanoparticles were included. The specimens were stored in deionized water at 37°C for 7, 15, 30, 60, and 120 days, and each solution was analyzed using atomic absorption spectroscopy. Silver was not detected in deionized water regardless of the silver nanoparticles added to the resin and of the storage period. Micrographs showed that with lower concentrations, the distribution of silver nanoparticles was reduced, whereas their dispersion was improved in the polymer. Moreover, after 120 days of storage, nanoparticles were mainly located on the surface of the nanocomposite specimens. Incorporation of silver nanoparticles in the acrylic resin was evidenced. Moreover, silver was not detected by the detection limit of the atomic absorption spectrophotometer used in this study, even after 120 days of storage in deionized water. Silver nanoparticles are incorporated in the PMMA denture resin to attain an effective antimicrobial material to help control common infections involving oral mucosal tissues in complete denture wearers. © 2011 by the American College of Prosthodontists.

Silver chromate and silver dichromate nanostructures: Sonochemical synthesis, characterization, and photocatalytic properties

International Nuclear Information System (INIS)

Soofivand, Faezeh; Mohandes, Fatemeh; Salavati-Niasari, Masoud

2013-01-01

Graphical abstract: In this work, Ag 2 CrO 4 and Ag 2 Cr 2 O 7 nanostructures have been sonochemically prepared using silver salicylate. The effect of preparation parameters on the morphology of the products was investigated by SEM images. Highlights: ► Herein, Ag 2 CrO 4 and Ag 2 Cr 2 O 7 nanostructures have been sonochemically prepared. ► The effect of preparation parameters on the morphology of the products was investigated. ► The photocatalytic activity of the as-prepared Ag 2 CrO 4 nanoparticles was tested. ► XPS spectra indicated the high purity of Ag 2 Cr 2 O 7 nanostructures obtained. - Abstract: In this work, Ag 2 CrO 4 and Ag 2 Cr 2 O 7 nanostructures have been produced via a sonochemical method using silver salicylate as precursor. Besides silver salicylate, Na 2 CrO 4 and (NH 4 ) 2 Cr 2 O 7 as starting reagents were applied. To investigate the effect of preparation parameters on the morphology and particle size of Ag 2 CrO 4 and Ag 2 Cr 2 O 7 , sonication time, type of surfactant and its concentration were changed. The as-produced nanostructures were characterized by techniques like powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The scanning electron micrographs showed that particle-like and rod-like nanostructures of Ag 2 CrO 4 and Ag 2 Cr 2 O 7 were produced using different surfactants. To investigate the catalytic properties of Ag 2 CrO 4 nanoparticles, photooxidation of methyl orange (MO) was performed. According to the obtained results, it was found that the methyl orange degradation was about 87.3% after 280 min irradiation of visible light

Biosynthesis of silver nanoparticles from Tribulus terrestris and its antimicrobial activity: a novel biological approach.

Science.gov (United States)

Gopinath, V; MubarakAli, D; Priyadarshini, S; Priyadharsshini, N Meera; Thajuddin, N; Velusamy, P

2012-08-01

In the recent decades, increased development of green synthesis of nanoparticles is inevitable because of its incredible applications in all fields of science. There were numerous work have been produced based on the plant and its extract mediated synthesis of nanoparticles, in this present study to explore that the novel approaches for the biosynthesis of silver nanoparticles using plant fruit bodies. The plant, Tribulus terrestris L. fruit bodies are used in this study, where the dried fruit body extract was mixed with silver nitrate in order to synthesis of silver nanoparticles. The active phytochemicals present in the plant were responsible for the quick reduction of silver ion (Ag(+)) to metallic silver nanoparticles (Ag(0)). The reduced silver nanoparticles were characterized by Transmission Electron Microscope (TEM), Atomic Force Microscope (AFM), XRD, FTIR, UV-vis spectroscopy. The spherical shaped silver nanoparticles were observed and it was found to be 16-28 nm range of sizes. The diffraction pattern also confirmed that the higher percentage of silver with fine particles size. The antibacterial property of synthesized nanoparticles was observed by Kirby-Bauer method with clinically isolated multi-drug resistant bacteria such as Streptococcus pyogens, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The plant materials mediated synthesis of silver nanoparticles have comparatively rapid and less expensive and wide application to antibacterial therapy in modern medicine. Copyright © 2012 Elsevier B.V. All rights reserved.

Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

Science.gov (United States)

Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li, Zi-An; Farle, Michael; Köller, Manfred; Epple, Matthias

2012-10-01

Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly( N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 μg mL-1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

75 FR 24394 - Animal Drugs, Feeds, and Related Products; Withdrawal of Approval of a New Animal Drug...

Science.gov (United States)

2010-05-05

... [Docket No. FDA-2010-N-0002] Animal Drugs, Feeds, and Related Products; Withdrawal of Approval of a New Animal Drug Application; Buquinolate; Coumaphos AGENCY: Food and Drug Administration, HHS. ACTION: Final rule. SUMMARY: The Food and Drug Administration (FDA) is amending the animal drug regulations by...

In vitro percutaneous penetration and characterization of silver from silver-containing textiles

Directory of Open Access Journals (Sweden)

Bianco C

2015-03-01

Full Text Available Carlotta Bianco,1 Sanja Kezic,2 Matteo Crosera,1 Vesna Svetličić,3 Suzana Šegota,3 Giovanni Maina,4 Canzio Romano,5 Francesca Larese,6,7 Gianpiero Adami11Department of Chemical and Pharmaceutical Sciences, University of Trieste, Trieste, Italy; 2Academic Medical Center, Coronel Institute, University of Amsterdam, Amsterdam, the Netherlands; 3Laboratory for Bioelectrochemistry and Surface Imaging, Division for Marine and Environmental Research, Ruder Boškovic Institute, Zagreb, Croatia; 4Department of Clinical and Biological Sciences, University of Turin, Turin, Italy; 5Department of Public and Pediatric Health Sciences, University of Turin, Turin, Italy; 6Unit of Occupational Medicine, University of Trieste, Trieste, Italy; 7Department of Medical Sciences, University of Trieste, Trieste, ItalyAbstract: The objective of this study was to determine the in vitro percutaneous penetration of silver and characterize the silver species released from textiles in different layers of full thickness human skin. For this purpose, two different wound dressings and a garment soaked in artificial sweat were placed in the donor compartments of Franz cells for 24 hours. The concentration of silver in the donor phase and in the skin was determined by an electrothermal atomic absorption spectrometer (ET-AAS and by inductively coupled plasma mass spectrometer (ICP-MS. The characterization of silver species in the textiles and in the skin layers was made by scanning electron microscopy with integrated energy dispersive X-ray spectroscopy (SEM-EDX. Additionally, the size distribution of silver nanoparticles in the textiles was performed by atomic force microscopy (AFM. On the surface of all investigated materials, silver nanoparticles of different size and morphology were found. Released silver concentrations in the soaking solutions (ie, exposure concentration ranged from 0.7 to 4.7 µg/mL (0.6–4.0 µg/cm2, fitting the bactericidal range. Silver and silver

TTC- Based Test as an Efficient Method to Determine Antibiofilm Activity of Silver Nanoparticles

Directory of Open Access Journals (Sweden)

Chojniak Joanna

2017-01-01

Full Text Available Among metal nanoparticles, silver nanoparticles are a widely used in various life sectors such as in biomedical applications, air and water purification, food production, cosmetics, garments and in various household products. There are several methods for production of silver nanoparticles. Generally, silver nanoparticles can be prepared by chemical methods such as chemical reduction and electrochemical techniques, physical methods, and biological methods such as the use of microorganisms. The biological route of synthesis provides a great diversity in choice for its raw materials such as bacteria, algae, fungi and plants. The aim of the study was to evaluate the tetrazolium/formazan test as a method to determine antibiofilm activity of biological synthetized silver nanoparticles. In this study Bacillus subtilis grown on brewery effluent and produced biosurfactant was used for silver nanoparticles (Ag-NPs synthesis. The culture supernatants were used in synthesis of Ag-NPs. The formation of nanoparticles accompanied by colour changes of the used reaction system was confirmed by UV-vis spectroscopy. The bacteria isolated from the biofilm of water supply system were used in the evaluation of the antibiofilm activity of biologically synthetized Ag-NPs. To compare the results the commonly used crystal violet assay (CV for biofilm analysis was applied.

Plasmonic characterization of photo-induced silver nanoparticles extracted from silver halide based TEM film

Energy Technology Data Exchange (ETDEWEB)

Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Rai, V. N.; Srivastava, A. K. [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India); Varshney, G. K. [Laser Bio-medical Applications & Instrumentation Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India)

2016-05-23

The plasmonic responses of silver nanoparticles extracted from silver halide based electron microscope film are investigated. Photo-reduction process is carried out to convert the silver halide grains into the metallic silver. The centrifuge technique is used for separating the silver nanoparticles from the residual solution. Morphological study performed by field emission scanning electron microscope (FESEM) shows that all the nanoparticles have an average diameter of ~120 nm with a high degree of mono dispersion in size. The localized surface plasmon resonance (LSPR) absorption peak at ~537 nm confirms the presence of large size silver nanoparticles.

Green Synthesis of Silver Nanoparticles Using Avena sativa L. Extract

Directory of Open Access Journals (Sweden)

Nooshin Amini

2017-02-01

Full Text Available Objective(s: Nowadays, nanoparticles bio production, considering their performance in medicine and biological science, is increasing. Green synthesis of metal nanoparticles using organisms has emerged as a nontoxic and ecofriendly method for synthesis of metal nanoparticles The objectives of this study were the production of silver nanoparticles using Avena sativa L. extract and optimization of the biosynthesis process. The effects of quantity of substrate (silver nitrate (AgNo3 and temperature on the formation of silver nanoparticles are studied. Methods: In this work, silver nanoparticles were synthesized from an extract of Avena sativa L. at different temperatures (30° C, 60° C, 90° C  and AgNo3 concentrations( 1 mM, 2mM, 4mM . The morphology and size of the nanoparticles were determined using Scanning Electron Microscope (SEM and Dynamic Light Scattering (DLS. Results: SEM images showed that by increasing temperature nanoparticles size were decreased and by increasing concentrations of AgNo3 the number of nanoparticles was increased. Conclusions: The results indicated that by increasing the reaction temperature, the size of the nanoparticles would decrease. Also by increasing the concentrations of AgNo3, the amount of produced nanoparticles would be increased, but won't have a significant effect on its size. The preparation of nano- structured silver particles using Avena sativa L. extract provides an environmentally friendly option as compared to currently available chemical/ physical methods.

Development and Optimization of Silver Nanoparticle Formulation for Fabrication

Science.gov (United States)

2015-08-14

steady increase in multi - drug resistant organisms. Therefore , the development of next generation antimicrobial compounds , such as silver...information. Publication Clearance Request (CPP- 1) Version 9.3: 10.2014 D Animal Use Research Protocol No.: List the IACUC that approved the...nanoparticles, is a priority. However , due to the inconsistencies in current fabrication and processing methods , it is unclear whether the antimicrobial

High aspect ratio silver grid transparent electrodes using UV embossing process

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Dong Jin Kim

2017-10-01

Full Text Available This study presents a UV embossing process to fabricate high aspect ratio silver grid transparent electrodes on a polymer film. Transparent electrodes with a high optical transmittance (93 % and low sheet resistance (4.6 Ω/sq were fabricated without any high temperature or vacuum processes. The strong adhesion force between the UV resin and the silver ink enables the fabrication of silver microstructures with an aspect ratio higher than 3. The high aspect ratio results in a low sheet resistance while maintaining a high optical transmittance. Multi-layer transparent electrodes were fabricated by repeating the proposed UV process. Additionally, a large-area of 8-inch touch panel was fabricated with the proposed UV process. The proposed UV process is a relatively simple and low cost process making it suitable for large-area production as well as mass production.

Green Synthesis of Silver Nanoparticles Using Pinus eldarica Bark Extract

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Siavash Iravani

2013-01-01

Full Text Available Recently, development of reliable experimental protocols for synthesis of metal nanoparticles with desired morphologies and sizes has become a major focus of researchers. Green synthesis of metal nanoparticles using organisms has emerged as a nontoxic and ecofriendly method for synthesis of metal nanoparticles. The objectives of this study were production of silver nanoparticles using Pinus eldarica bark extract and optimization of the biosynthesis process. The effects of quantity of extract, substrate concentration, temperature, and pH on the formation of silver nanoparticles are studied. TEM images showed that biosynthesized silver nanoparticles (approximately in the range of 10–40 nm were predominantly spherical in shape. The preparation of nano-structured silver particles using P. eldarica bark extract provides an environmentally friendly option, as compared to currently available chemical and/or physical methods.

Synthesis and characterization of silver nanoparticles by sol-gel route from silver nitrate

International Nuclear Information System (INIS)

Morales, Jorge; Moran, Jose; Quintana, Maria; Estrada, Walter

2009-01-01

Silver nanoparticles colloids have been synthesized by sol-gel method. This synthesis consists in silver nitrate reduction by ethylene glycol in a process called polyol. The growth of the nanoparticles have been controlled by the steric stabilization of the colloid with polyvinylpyrrolidone (PVP, M w = 40 000). The silver nanoparticle size and structure was depending on the control of parameters such as: molar concentrations ratio of silver nitrate and PVP, temperature of reaction and the reflux time. Colloids have been characterized by UV-vis spectroscopy in the range from 300 to 1000 nm. The results show that the typical peak of surface plasmon resonance is formed at 400-450 nm indicating the formation of silver nanoparticles. The presences of silver nanoparticles of spherical shape with size among 20-40 nm were observed by transmission electronic microscopy (TEM). Electron diffraction patterns confirmed that synthesized colloids contain metallic silver with a crystal structure face centered cubic FCC. (author)

77 FR 43662 - Price for the 2012 American Eagle Silver Proof Coin

Science.gov (United States)

2012-07-25

... DEPARTMENT OF THE TREASURY United States Mint Price for the 2012 American Eagle Silver Proof Coin... is lowering the price of the 2012 American Eagle Silver Proof Coin. The product will now be offered for sale at a price of $54.95. FOR FURTHER INFORMATION CONTACT: B. B. Craig, Associate Director for...

Silver and Nitrate Oppositely Modulate Antimony Susceptibility through Aquaglyceroporin 1 in Leishmania (Viannia) Species.

Science.gov (United States)

Andrade, Juvana M; Baba, Elio H; Machado-de-Avila, Ricardo A; Chavez-Olortegui, Carlos; Demicheli, Cynthia P; Frézard, Frédéric; Monte-Neto, Rubens L; Murta, Silvane M F

2016-08-01

Antimony (Sb) resistance in leishmaniasis chemotherapy has become one of the major challenges to the control of this spreading worldwide public health problem. Since the plasma membrane pore-forming protein aquaglyceroporin 1 (AQP1) is the major route of Sb uptake in Leishmania, functional studies are relevant to characterize drug transport pathways in the parasite. We generated AQP1-overexpressing Leishmania guyanensis and L. braziliensis mutants and investigated their susceptibility to the trivalent form of Sb (Sb(III)) in the presence of silver and nitrate salts. Both AQP1-overexpressing lines presented 3- to 4-fold increased AQP1 expression levels compared with those of their untransfected counterparts, leading to an increased Sb(III) susceptibility of about 2-fold. Competition assays using silver nitrate, silver sulfadiazine, or silver acetate prior to Sb(III) exposure increased parasite growth, especially in AQP1-overexpressing mutants. Surprisingly, Sb(III)-sodium nitrate or Sb(III)-potassium nitrate combinations showed significantly enhanced antileishmanial activities compared to those of Sb(III) alone, especially against AQP1-overexpressing mutants, suggesting a putative nitrate-dependent modulation of AQP1 activity. The intracellular level of antimony quantified by graphite furnace atomic absorption spectrometry showed that the concomitant exposure to Sb(III) and nitrate favors antimony accumulation in the parasite, increasing the toxicity of the drug and culminating with parasite death. This is the first report showing evidence of AQP1-mediated Sb(III) susceptibility modulation by silver in Leishmania and suggests the potential antileishmanial activity of the combination of nitrate salts and Sb(III). Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Electrochemical detection of commercial silver nanoparticles: identification, sizing and detection in environmental media

International Nuclear Information System (INIS)

Stuart, E J E; Tschulik, K; Compton, R G; Omanović, D; Cullen, J T; Jurkschat, K; Crossley, A

2013-01-01

The electrochemistry of silver nanoparticles contained in a consumer product has been studied. The redox properties of silver particles in a commercially available disinfectant cleaning spray were investigated via cyclic voltammetry before particle-impact voltammetry was used to detect single particles in both a typical aqueous electrolyte and authentic seawater media. We show that particle-impact voltammetry is a promising method for the detection of nanoparticles that have leached into the environment from consumer products, which is an important development for the determination of risks associated with the incorporation of nanotechnology into everyday products. (paper)

Use of a silver ion selective electrode to assess mechanisms responsible for biological effects of silver nanoparticles

International Nuclear Information System (INIS)

Koch, Marcus; Kiefer, Silke; Cavelius, Christian; Kraegeloh, Annette

2012-01-01

For a detailed analysis of the biological effects of silver nanoparticles, discrimination between effects related to the nano-scale size of the particles and effects of released silver ions is required. Silver ions are either present in the initial particle dispersion or released by the nanoparticles over time. The aim of this study is to monitor the free silver ion activity {Ag + } in the presence of silver nanoparticles using a silver ion selective electrode. Therefore, silver in the form of silver nanoparticles, 4.2 ± 1.4 nm and 2–30 nm in size, or silver nitrate was added to cell culture media in the absence or presence of A549 cells as a model for human type II alveolar epithelial cells. The free silver ion activity measured after the addition of silver nanoparticles was determined by the initial ionic silver content. The p {Ag + } values indicated that the cell culture media decrease the free silver ion activity due to binding of silver ions by constituents of the media. In the presence of A549 cells, the free silver ion activity was further reduced. The morphology of A549 cells, cultivated in DME medium containing 9.1% (v/v) FBS, was affected by adding AgNO 3 at concentrations of ≥30 μM after 24 h. In comparison, silver nanoparticles up to a concentration of 200 μM Ag did not affect cellular morphology. Our experiments indicate that the effect of silver nanoparticles is mainly mediated by silver ions. An effect of silver on cellular morphology was observed at p {Ag + } ≤ 9.2.

Processing and properties of silver-metal oxide electrical contact materials

Directory of Open Access Journals (Sweden)

Nadežda M. Talijan

2012-12-01

Full Text Available The presented study gives a brief overview of the experimental results of investigations of different production technologies of silver-metal oxide electrical contact materials in relation: processing method - properties. The two most common routes of production, i.e. internal oxidation/ingot metallurgy and powder metallurgy are demonstrated on the example of Ag-CdO and Ag-ZnO materials. For illustration of alternative processing routes that provide higher dispersion of metal-oxide particles in silver matrix more environmentally friendly Ag-SnO2 contact materials are used. Processing of electrical contact materials by mechanical mixing of starting powders in high energy ball mill is presented. The obtained experimental results of application of different methods of introduction of SnO2 nanoparticles in the silver matrix such as conventional powder metallurgy mixing and template method are given and discussed in terms of their influence on microstructure and physical properties (density, hardness and electrical conductivity of the prepared Ag-SnO2 electrical contact materials.

Colloidal silver fabrication using the spark discharge system and its antimicrobial effect on Staphylococcus aureus.

Science.gov (United States)

Tien, Der-Chi; Tseng, Kuo-Hsiung; Liao, Chih-Yu; Tsung, Tsing-Tshih

2008-10-01

Nanoscale techniques for silver production may assist the resurgence of the medical use of silver, especially given that pathogens are showing increasing resistance to antibiotics. Traditional chemical synthesis methods for colloidal silver (CS) may lead to the presence of toxic chemical species or chemical residues, which may inhibit the effectiveness of CS as an antibacterial agent. To counter these problems a spark discharge system (SDS) was used to fabricate a suspension of colloidal silver in deionized water with no added chemical surfactants. SDS-CS contains both metallic silver nanoparticles (Ag(0)) and ionic silver forms (Ag(+)). The antimicrobial affect of SDS-CS on Staphylococcus aureus was studied. The results show that CS solutions with an ionic silver concentration of 30 ppm or higher are strong enough to destroy S. aureus. In addition, it was found that a solution's antimicrobial potency is directly related to its level of silver ion concentration.

Voltammetric determination of sodium anthraquinone-2-sulfonate using silver solid amalgam electrodes

Czech Academy of Sciences Publication Activity Database

Skalová, Štěpánka; Navrátil, Tomáš; Barek, J.; Vyskočil, V.

2017-01-01

Roč. 148, č. 3 (2017), s. 577-583 ISSN 0026-9247 Institutional support: RVO:61388955 Keywords : Anthraquinone * Drugs * Silver solid amalgam electrode * Voltammetry Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 1.282, year: 2016

Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

Energy Technology Data Exchange (ETDEWEB)

Mahl, Dirk; Diendorf, Joerg; Ristig, Simon [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Greulich, Christina [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Li Zian; Farle, Michael [University of Duisburg-Essen, Faculty of Physics, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Koeller, Manfred [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Epple, Matthias, E-mail: matthias.epple@uni-due.de [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

2012-10-15

Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 {mu}g mL{sup -1} induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

Defining Patient Centric Pharmaceutical Drug Product Design.

Science.gov (United States)

Stegemann, Sven; Ternik, Robert L; Onder, Graziano; Khan, Mansoor A; van Riet-Nales, Diana A

2016-09-01

The term "patient centered," "patient centric," or "patient centricity" is increasingly used in the scientific literature in a wide variety of contexts. Generally, patient centric medicines are recognized as an essential contributor to healthy aging and the overall patient's quality of life and life expectancy. Besides the selection of the appropriate type of drug substance and strength for a particular indication in a particular patient, due attention must be paid that the pharmaceutical drug product design is also adequately addressing the particular patient's needs, i.e., assuring adequate patient adherence and the anticipate drug safety and effectiveness. Relevant pharmaceutical design aspects may e.g., involve the selection of the route of administration, the tablet size and shape, the ease of opening the package, the ability to read the user instruction, or the ability to follow the recommended (in-use) storage conditions. Currently, a harmonized definition on patient centric drug development/design has not yet been established. To stimulate scientific research and discussions and the consistent interpretation of test results, it is essential that such a definition is established. We have developed a first draft definition through various rounds of discussions within an interdisciplinary AAPS focus group of experts. This publication summarizes the outcomes and is intended to stimulate further discussions with all stakeholders towards a common definition of patient centric pharmaceutical drug product design that is useable across all disciplines involved.

Therapeutic Potential of Biologically Reduced Silver Nanoparticles from Actinomycete Cultures

International Nuclear Information System (INIS)

Sukanya, M.K.; Saju, K.A.; Praseetha, P.K.; Sakthivel, G.

2013-01-01

Silver nanoparticles are applied in nanomedicine from time immemorial and are still used as powerful antibiotic and anti-inflammatory agents. Antibiotics produced by actinomycetes are popular in almost all the therapeutic measures, and this study has proven that these microbes are also helpful in the biosynthesis of silver nanoparticles with good surface and size characteristics. Silver can be synthesized by various chemical methodologies, and most of them have turned to be toxic. This study has been successful in isolating the microbes from polluted environment, and subjecting them to the reduction of silver nanoparticles, characterizing the nanoparticles by UV spectrophotometry and transmission electron microscopy. The nanoparticles produced were tested for their antimicrobial property, and the zone of inhibition was greater than those produced by their chemically synthesized counterparts. Actinomycetes, helpful in bioremediating heavy metals, are useful for the production of metallic nanoparticles. The biosynthesized silver nanoparticles loaded with antibiotics prove to be better in killing the pathogens and have opened up new areas for developing nanobiotechnological research based on microbial applications.

78 FR 37231 - Guidance for Industry; Guidance on Abbreviated New Drug Applications: Stability Testing of Drug...

Science.gov (United States)

2013-06-20

.... 2201, Silver Spring, MD 20993-0002. Send one self-addressed adhesive label to assist the office in... comments to the Division of Dockets Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane...

A Study of Antibioactivity of Nanosilver Colloid and Silver Ion Solution

Directory of Open Access Journals (Sweden)

Kuo-Hsiung Tseng

2014-01-01

Full Text Available The colloidal silver solution was successfully prepared in dielectric fluid by using electrical spark discharge (ESD without any surfactants. It does not require the toxic chemical agents in the process, which may affect the effectiveness of nanosilver colloid as an antibacterial agent. Nanocolloidal silver produced by ESD is characterized as low cost, zero environmental pollution, continuous, and rapid mass production process. In order to test the effect of antibioactivity, nanosilver dough was tested; the silver nanofluid was prepared by ESD machine, made into dough at different concentrations, and fermented for three hours in order to observe changes in the diameter of the dough. The results showed that the effect of effectiveness of nanosilver at the concentration of 100 ppm was weak, whereas the effect of 60 ppm silver ion (100 ppm AgNO3 was significant, as the dissociation rate of silver ion concentration correlates to the antibioactivity.

Antibacterial and anti-adhesion effects of the silver nanoparticles-loaded poly(L-lactide) fibrous membrane

International Nuclear Information System (INIS)

Liu, Shen; Zhao, Jingwen; Ruan, Hongjiang; Wang, Wei; Wu, Tianyi; Cui, Wenguo; Fan, Cunyi

2013-01-01

The complications of tendon injury are frequently compromised by peritendinous adhesions and tendon sheath infection. Physical barriers for anti-adhesion may increase the incidence of postoperative infection. This study was designed to evaluate the potential of silver nanoparticles (AgNPs)-loaded poly(L-lactide) (PLLA) electrospun fibrous membranes to prevent adhesion formation and infection. Results of an in vitro drug release study showed that a burst release was followed by sustained release from electrospun fibrous membranes with a high initial silver content. Fewer fibroblasts adhered to and proliferated on the AgNP-loaded PLLA electrospun fibrous membranes compared with pure PLLA electrospun fibrous membrane. In the antibacterial test, the AgNP-loaded PLLA electrospun fibrous membranes can prevent the adhesion of Gram-positive Staphylococcus aureus and Staphylococcus epidermidis and Gram-negative Pseudomonas aeruginosa. Taken together, these results demonstrate that AgNP-loaded PLLA electrospun fibrous membranes have the convenient practical medical potential of reduction of infection and adhesion formation after tendon injury. - Highlights: ► Silver nanoparticles are directly electrospun into PLLA fibrous membrane. ► Long-lasting release of Ag + ions is achieved. ► Cytotoxicity of silver ions benefits the anti-proliferation of physical barriers. ► Broad anti-microbial effect of drug-loaded fibrous membrane is revealed. ► Antibacterial and anti-adhesion effects of the physical barriers are combined

Room temperature synthesis of silver nanowires from tabular silver bromide crystals in the presence of gelatin

Science.gov (United States)

Liu, Suwen; Wehmschulte, Rudolf J.; Lian, Guoda; Burba, Christopher M.

2006-03-01

Long silver nanowires were synthesized at room temperature by a simple and fast process derived from the development of photographic films. A film consisting of an emulsion of tabular silver bromide grains in gelatin was treated with a photographic developer (4-(methylamino)phenol sulfate (metol), citric acid) in the presence of additional aqueous silver nitrate. The silver nanowires have lengths of more than 50 μm, some even more than 100 μm, and average diameters of about 80 nm. Approximately, 70% of the metallic silver formed in the reduction consists of silver nanowires. Selected area electron diffraction (SAED) results indicate that the silver nanowires grow along the [111] direction. It was found that the presence of gelatin, tabular silver bromide crystals and silver ions in solution are essential for the formation of the silver nanowires. The nanowires appear to originate from the edges of the silver bromide crystals. They were characterized by transmission electron microscopy (TEM), SAED, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD).

Room temperature synthesis of silver nanowires from tabular silver bromide crystals in the presence of gelatin

International Nuclear Information System (INIS)

Liu Suwen; Wehmschulte, Rudolf J.; Lian Guoda; Burba, Christopher M.

2006-01-01

Long silver nanowires were synthesized at room temperature by a simple and fast process derived from the development of photographic films. A film consisting of an emulsion of tabular silver bromide grains in gelatin was treated with a photographic developer (4-(methylamino)phenol sulfate (metol), citric acid) in the presence of additional aqueous silver nitrate. The silver nanowires have lengths of more than 50 μm, some even more than 100 μm, and average diameters of about 80 nm. Approximately, 70% of the metallic silver formed in the reduction consists of silver nanowires. Selected area electron diffraction (SAED) results indicate that the silver nanowires grow along the [111] direction. It was found that the presence of gelatin, tabular silver bromide crystals and silver ions in solution are essential for the formation of the silver nanowires. The nanowires appear to originate from the edges of the silver bromide crystals. They were characterized by transmission electron microscopy (TEM), SAED, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD)

21 CFR 330.3 - Imprinting of solid oral dosage form drug products.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Imprinting of solid oral dosage form drug products... AS SAFE AND EFFECTIVE AND NOT MISBRANDED General Provisions § 330.3 Imprinting of solid oral dosage form drug products. A requirement to imprint an identification code on solid oral dosage form drug...

Package selection for moisture protection for solid, oral drug products.

Science.gov (United States)

Waterman, Kenneth C; MacDonald, Bruce C

2010-11-01

This review describes how best to select the appropriate packaging options for solid, oral drug products based on both chemical and physical stability, with respect to moisture protection. This process combines an accounting for the initial moisture content of dosage form components, moisture transfer into (out of) packaging based on a moisture vapor transfer rate (MVTR), and equilibration between drug products and desiccants based on their moisture sorption isotherms to provide an estimate of the instantaneous relative humidity (RH) within the packaging. This time-based RH is calculationally combined with a moisture-sensitive Arrhenius equation (determined using the accelerated stability assessment program, ASAP) to predict the drug product's chemical stability over time as a function of storage conditions and packaging options. While physical stability of dosage forms with respect to moisture has been less well documented, a process is recommended based on the threshold RH at which changes (e.g., dosage form dissolution, tablet hardness, drug form) become problematic. The overall process described allows packaging to be determined for a drug product scientifically, with the effect of any changes to storage conditions or packaging to be explicitly accounted for. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Fractionation of silver isotopes in native silver explained by redox reactions

Science.gov (United States)

Mathur, Ryan; Arribas, Antonio; Megaw, Peter; Wilson, Marc; Stroup, Steven; Meyer-Arrivillaga, Danilo; Arribas, Isabel

2018-03-01

Scant data exist on the silver isotope composition of native silver specimens because of the relative newness of the technique. This study increases the published dataset by an order of magnitude and presents 80 silver new isotope analyses from native silver originating from a diverse set of worldwide deposits (8 deposit types, 33 mining districts in five continents). The measured isotopic range (defined as δ109Ag/107Ag in per mil units compared to NIST 978 Ag isotope standard) is +2.1 to -0.86‰ (2σ errors less than 0.015); with no apparent systematic correlations to date with deposit type or even within districts. Importantly, the data centering on 0‰ all come from high temperature hypogene/primary deposits whereas flanking and overlapping data represent secondary supergene deposits. To investigate the causes for the more fractionated values, several laboratory experiments involving oxidation of silver from natural specimens of Ag-rich sulfides and precipitation and adsorption of silver onto reagent grade MnO2 and FeOOH were conducted. Simple leach experiments demonstrate little Ag isotope fractionation occurred through oxidation of Ag from native Ag (Δsolution-native109Ag = 0.12‰). In contrast, significant fractionation occurred through precipitation of native Ag onto MnO2 (up to Δsolution-MnO2109Ag = 0.68‰, or 0.3amu). Adsorption of silver onto the MnO2 and FeOOH did not produce as large fractionation as precipitation (mean value of Δsolution-MnO2109Ag = 0.10‰). The most likely cause for the isotopic variations seen relates to redox effects such as the reduction of silver from Ag (I) to Ag° that occurs during precipitation onto the mineral surface. Since many Ag deposits have halos dominated by MnO2 and FeOOH phases, potential may exist for the silver isotope composition of ores and surrounding geochemical haloes to be used to better understand ore genesis and potential exploration applications. Aside from the Mn oxides, surface fluid silver

Silver deposition on stainless steel container surfaces in contact with disinfectant silver aqueous solutions

International Nuclear Information System (INIS)

Petala, M.; Tsiridis, V.; Mintsouli, I.; Pliatsikas, N.; Spanos, Th.; Rebeyre, P.; Darakas, E.; Patsalas, P.; Vourlias, G.; Kostoglou, M.; Sotiropoulos, S.; Karapantsios, Th.

2017-01-01

Highlights: • Silver is one of the biocides of water consumed in the International Space Station. • Ionic silver is depleted from potable water when in contact with stainless steel (SS). • SEM and XPS analysis reveal a uniform silver deposition over the SS surface. • Silver deposits in its metallic form, in line with a galvanic deposition mechanism. • Evidence is provided that Cr and/ or Ni oxide builds-up on SS surfaces. - Abstract: Silver is the preservative used on the Russian segment of the International Space Station (ISS) to prevent microbial proliferation within potable water supplies. Yet, in the frame of the European Automated Transfer Vehicle (ATV) missions to ISS, silver depletion from water has been detected during ground transportation of this water to launch site, thereby indicating a degradation of water quality. This study investigates the silver loss from water when in contact with stainless steel surfaces. Experiments are conducted with several types of stainless steel surfaces being exposed to water containing 10 or 0.5 mg/L silver ions. Results show that silver deposits on stainless steel surfaces even when a passivation layer protects the metallic surface. The highest protection to silver deposition is offered by acid passivated and electropolished SS 316L. SEM and XPS experiments were carried out at several locations of the sample area that was in contact with the Ag solution and found similar morphological (SEM) and compositional (sputter-etch XPS) results. The results reveal that silver deposits uniformly across the wetted surface to a thickness larger than 3 nm. Moreover, evidence is provided that silver deposits in its metallic form on all stainless steel surfaces, in line with a galvanic deposition mechanism. Combination of ICP-MS and XPS results suggests a mechanism for Ag deposition/reduction with simultaneous substrate oxidation resulting in oxide growth at the exposed stainless steel surface.

Silver deposition on stainless steel container surfaces in contact with disinfectant silver aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Petala, M., E-mail: petala@civil.auth.gr [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Tsiridis, V. [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Mintsouli, I. [Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Pliatsikas, N. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Spanos, Th. [Department of Petroleum and Mechanical Engineering Sciences, Eastern Macedonia and Thrace Institute of Technology, Kavala, 65404 (Greece); Rebeyre, P. [ESA/ESTEC, P.O.Box 299, 2200 AG, Noordwijk (Netherlands); Darakas, E. [Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Patsalas, P.; Vourlias, G. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece); Kostoglou, M.; Sotiropoulos, S.; Karapantsios, Th. [Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54124 (Greece)

2017-02-28

Highlights: • Silver is one of the biocides of water consumed in the International Space Station. • Ionic silver is depleted from potable water when in contact with stainless steel (SS). • SEM and XPS analysis reveal a uniform silver deposition over the SS surface. • Silver deposits in its metallic form, in line with a galvanic deposition mechanism. • Evidence is provided that Cr and/ or Ni oxide builds-up on SS surfaces. - Abstract: Silver is the preservative used on the Russian segment of the International Space Station (ISS) to prevent microbial proliferation within potable water supplies. Yet, in the frame of the European Automated Transfer Vehicle (ATV) missions to ISS, silver depletion from water has been detected during ground transportation of this water to launch site, thereby indicating a degradation of water quality. This study investigates the silver loss from water when in contact with stainless steel surfaces. Experiments are conducted with several types of stainless steel surfaces being exposed to water containing 10 or 0.5 mg/L silver ions. Results show that silver deposits on stainless steel surfaces even when a passivation layer protects the metallic surface. The highest protection to silver deposition is offered by acid passivated and electropolished SS 316L. SEM and XPS experiments were carried out at several locations of the sample area that was in contact with the Ag solution and found similar morphological (SEM) and compositional (sputter-etch XPS) results. The results reveal that silver deposits uniformly across the wetted surface to a thickness larger than 3 nm. Moreover, evidence is provided that silver deposits in its metallic form on all stainless steel surfaces, in line with a galvanic deposition mechanism. Combination of ICP-MS and XPS results suggests a mechanism for Ag deposition/reduction with simultaneous substrate oxidation resulting in oxide growth at the exposed stainless steel surface.

Controllable synthesis of silver and silver sulfide nanocrystals via selective cleavage of chemical bonds

International Nuclear Information System (INIS)

Tang Aiwei; Wang Yu; Ye Haihang; Zhou Chao; Yang Chunhe; Li Xu; Peng Hongshang; Zhang Fujun; Hou Yanbing; Teng Feng

2013-01-01

A one-step colloidal process has been adopted to prepare silver (Ag) and silver sulfide (Ag 2 S) nanocrystals, thus avoiding presynthesis of an organometallic precursor and the injection of a toxic phosphine agent. During the reaction, a layered intermediate compound is first formed, which then acts as a precursor, decomposing into the nanocrystals. The composition of the as-obtained products can be controlled by selective cleavage of S–C bonds or Ag–S bonds. Pure Ag 2 S nanocrystals can be obtained by directly heating silver acetate (Ag(OAc)) and n-dodecanethiol (DDT) at 200 ° C without any surfactant, and pure Ag nanocrystals can be synthesized successfully if the reaction temperature is reduced to 190 ° C and the amount of DDT is decreased to 1 ml in the presence of a non-coordinating organic solvent (1-octadecene, ODE). Otherwise, the mixture of Ag and Ag 2 S is obtained by directly heating Ag(OAc) in DDT by increasing the reaction temperature or in a mixture of DDT and ODE at 200 ° C. The formation mechanism has been discussed in detail in terms of selective S–C and Ag–S bond dissociation due to the nucleophilic attack of DDT and the lower bonding energy of Ag–S. Interestingly, some products can easily self-assemble into two- or three-dimensional (2D or 3D) highly ordered superlattice structures on a copper grid without any additional steps. The excess DDT plays a key role in the superlattice structure due to the bundling and interdigitation of the thiolate molecules adsorbed on the as-obtained nanocrystals. (paper)

Product-line extensions and pricing strategies of brand-name drugs facing patent expiration.

Science.gov (United States)

Hong, Song Hee; Shepherd, Marvin D; Scoones, David; Wan, Thomas T H

2005-01-01

This study proposed an alternative to brand loyalty as the explanation for the continued price rigidity of patent-expired brand-name prescription drugs despite the increase in market entry of generic drugs facilitated by the 1984 Drug Price Competition and Patent Term Restoration Act. Study hypotheses were to test (1) whether market entries of new-product extensions are associated with market success of original brand-name drugs before generic drug entry, and (2) whether original brand-name drugs exhibit price rigidity to generic entry only when they are extended. The design is a retrospective follow-up study for the prescription drug brands that lost their patents between 1987 and 1992. The drug brands were limited to nonantibiotic, orally administered drugs containing only 1 active pharmaceutical ingredient. Information on patent expiration, entry of a product extension, and market success were determined from the U.S. Food and Drug Administration.s Orange Book, First DataBank, and American Druggist, respectively. Market success was defined as whether an original drug brand was listed in the top 100 prescriptions most frequently dispensed before facing generic entry. Product-line extension was defined as the appearance of another product that a company introduces within the same market after its existing product. Drug prices were average wholesale prices from the Drug Topics Red Book. The relationship between product-line extension and market success was examined using a logistic regression analysis. The price rigidity to entry was tested using a panel regression analysis. A total of 27 drug brands lost their patents between 1987 and 1992. Drug brands that achieved market success were 16 times more likely to be extended than were those that did not (OR=16, 95% confidence interval, 2.12-120.65). The price rigidity to entry existed in drug brands with extensions (beta=2.65%, P new product-line extension introduced for an original brand helps the original price be

Plant natural products research in tuberculosis drug discovery and ...

African Journals Online (AJOL)

Plant natural products research in tuberculosis drug discovery and development: A situation report ... African Journal of Biotechnology ... tuberculosis (XDR-TB), call for the development of new anti-tuberculosis drugs to combat this disease.

Reactivity and Catalytic Activity of Hydrogen Atom Chemisorbed Silver Clusters.

Science.gov (United States)

Manzoor, Dar; Pal, Sourav

2015-06-18

Metal clusters of silver have attracted recent interest of researchers as a result of their potential in different catalytic applications and low cost. However, due to the completely filled d orbital and very high first ionization potential of the silver atom, the silver-based catalysts interact very weakly with the reacting molecules. In the current work, density functional theory calculations were carried out to investigate the effect of hydrogen atom chemisorption on the reactivity and catalytic properties of inert silver clusters. Our results affirm that the hydrogen atom chemisorption leads to enhancement in the binding energy of the adsorbed O2 molecule on the inert silver clusters. The increase in the binding energy is also characterized by the decrease in the Ag-O and increase in the O-O bond lengths in the case of the AgnH silver clusters. Pertinent to the increase in the O-O bond length, a significant red shift in the O-O stretching frequency is also noted in the case of the AgnH silver clusters. Moreover, the hydrogen atom chemisorbed silver clusters show low reaction barriers and high heat of formation of the final products for the environmentally important CO oxidation reaction as compared to the parent catalytically inactive clusters. The obtained results were compared with those of the corresponding gold and hydrogen atom chemisorbed gold clusters obtained at the same level of theory. It is expected the current computational study will provide key insights for future advances in the design of efficient nanosilver-based catalysts through the adsorption of a small atom or a ligand.

Increased immunoglobulin production in silver catfish (Rhamdia quelen exposed to agrichemicals

Directory of Open Access Journals (Sweden)

L.C. Kreutz

2014-06-01

Full Text Available Fish vaccination has been increasingly exploited as a tool to control pathogen infection. The production of immunoglobulin following vaccination might be affected by several factors such as management procedures, water temperature, and the presence of xenobiotics. In the present study, we aimed to investigate the kinetics of immunoglobulin production in silver catfish (Rhamdia quelen inoculated with inactivated Aeromonas hydrophila and kept at two different water temperatures (17.4±0.4° or 21.3±0.3°C. The effect of a second antigen inoculation and exposure of fish to sublethal concentrations of the herbicides atrazine and glyphosate at 10% of the lethal concentration (LC50-96h on specific serum antibodies were also investigated. Antibodies to A. hydrophila were detected as early as 7 days post-inoculation and increased steadily up to 35 days. The kinetics of antibody production were similar in fish kept at 17.4±0.4° and 21.3±0.3°C, and reinoculation of antigen at 21 days after priming failed to increase specific antibody levels. Intriguingly, we found that, in fish exposed to atrazine and glyphosate, the secretion of specific antibodies was higher than in non-exposed inoculated fish. These findings are important for the design of vaccines and vaccination strategies in Neotropical fish species. However, because atrazine and glyphosate are widespread contaminants of soil and water, their immune-stimulating effect could be harmful, in that fish living in herbicide-contaminated water might have increased concentrations of nonspecific antibodies that could mediate tissue injury.

Marine natural products: a new wave of drugs?

Science.gov (United States)

Montaser, Rana; Luesch, Hendrik

2011-01-01

The largely unexplored marine world that presumably harbors the most biodiversity may be the vastest resource to discover novel ‘validated’ structures with novel modes of action that cover biologically relevant chemical space. Several challenges, including the supply problem and target identification, need to be met for successful drug development of these often complex molecules; however, approaches are available to overcome the hurdles. Advances in technologies such as sampling strategies, nanoscale NMR for structure determination, total chemical synthesis, fermentation and biotechnology are all crucial to the success of marine natural products as drug leads. We illustrate the high degree of innovation in the field of marine natural products, which in our view will lead to a new wave of drugs that flow into the market and pharmacies in the future. PMID:21882941

Sensing of silver nanoparticles on/in endothelial cells using atomic force spectroscopy.

Science.gov (United States)

Kolodziejczyk, Agnieszka; Jakubowska, Aleksandra; Kucinska, Magdalena; Wasiak, Tomasz; Komorowski, Piotr; Makowski, Krzysztof; Walkowiak, Bogdan

2018-05-10

Endothelial cells, due to their location, are interesting objects for atomic force spectroscopy study. They constitute a barrier between blood and vessel tissues located deeper, and therefore they are the first line of contact with various substances present in blood, eg, drugs or nanoparticles. This work intends to verify whether the mechanical response of immortalized human umbilical vein endothelial cells (EA.hy926), when exposed to silver nanoparticles, as measured using force spectroscopy, could be effectively used as a bio-indicator of the physiological state of the cells. Silver nanoparticles were characterized with transmission electron microscopy and dynamic light scattering techniques. Tetrazolium salt reduction test was used to determine cell viability after treatment with silver nanoparticles. An elasticity of native cells was examined in the Hanks' buffer whereas fixed cells were softly fixed with formaldehyde. Additional aspect of the work is the comparative force spectroscopy utilizing AFM probes of ball-shape and conical geometries, in order to understand what changes in cell elasticity, caused by SNPs, were detectable with each probe. As a supplement to elasticity studies, cell morphology observation by atomic force microscopy and detection of silver nanoparticles inside cells using transmission electron microscopy were also performed. Cells exposed to silver nanoparticles at the highest selected concentrations (3.6 μg/mL, 16 μg/mL) are less elastic. It may be associated with the reorganization of the cellular cytoskeleton and the "strengthening" of the cell cortex caused by presence of silver nanoparticles. This observation does not depend on cell fixation. Agglomerates of silver nanoparticles were observed on the cell membrane as well as inside the cells. Copyright © 2018 John Wiley & Sons, Ltd.

Phytotoxicity of silver nanoparticles to Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Gubbins, Eva J. [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Batty, Lesley C., E-mail: l.c.batty@bham.ac.uk [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Lead, Jamie R. [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom)

2011-06-15

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. Although there has been some attempt to determine the toxic effects of AgNPs, there is little information on aquatic plants which have a vital role in ecosystems. This study reports the use of Lemna minor L. clone St to investigate the phytotoxicity of AgNPs under modified OECD test conditions. AgNPs were synthesised, characterised and subsequently presented to the L. minor. Results showed that inhibition of plant growth was evident after exposure to small ({approx}20 nm) and larger ({approx}100 nm) AgNPs at low concentrations (5 {mu}g L{sup -1}) and this effect became more acute with a longer exposure time. There was a linear dose-response relationship after 14 d exposure. Using predicted environmental concentrations for wastewaters it was found that AgNPs may pose a significant potential risk to the environment. - Highlights: > Silver nanoparticles are toxic to Lemna minor at concentrations of 5 {mu}g L{sup -1}. > The effect of silver nanoparticles varies with size and concentration. > Standard toxicity tests are not appropriate for application to NPs. > Silver nanoparticles pose a potential environmental risk based on modelled environmental concentrations. - Silver nanoparticles are toxic to Lemna minor at low concentrations and constitute a significant environmental risk.

Phytotoxicity of silver nanoparticles to Lemna minor L

International Nuclear Information System (INIS)

Gubbins, Eva J.; Batty, Lesley C.; Lead, Jamie R.

2011-01-01

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. Although there has been some attempt to determine the toxic effects of AgNPs, there is little information on aquatic plants which have a vital role in ecosystems. This study reports the use of Lemna minor L. clone St to investigate the phytotoxicity of AgNPs under modified OECD test conditions. AgNPs were synthesised, characterised and subsequently presented to the L. minor. Results showed that inhibition of plant growth was evident after exposure to small (∼20 nm) and larger (∼100 nm) AgNPs at low concentrations (5 μg L -1 ) and this effect became more acute with a longer exposure time. There was a linear dose-response relationship after 14 d exposure. Using predicted environmental concentrations for wastewaters it was found that AgNPs may pose a significant potential risk to the environment. - Highlights: → Silver nanoparticles are toxic to Lemna minor at concentrations of 5 μg L -1 . → The effect of silver nanoparticles varies with size and concentration. → Standard toxicity tests are not appropriate for application to NPs. → Silver nanoparticles pose a potential environmental risk based on modelled environmental concentrations. - Silver nanoparticles are toxic to Lemna minor at low concentrations and constitute a significant environmental risk.

Diclofenac and 2‐anilinophenylacetate degradation by combined activity of biogenic manganese oxides and silver

Science.gov (United States)

Meerburg, Francis; Hennebel, Tom; Vanhaecke, Lynn; Verstraete, Willy; Boon, Nico

2012-01-01

Summary The occurrence of a range of recalcitrant organic micropollutants in our aquatic environment has led to the development of various tertiary wastewater treatment methods. In this study, biogenic manganese oxides (Bio‐MnOx), biogenic silver nanoparticles (Bio‐Ag0) and ionic silver were used for the oxidative removal of the frequently encountered drug diclofenac and its dechlorinated form, 2‐anilinophenylacetate (APA). Diclofenac was rapidly degraded during ongoing manganese oxidation by Pseudomonas putida MnB6. Furthermore, whereas preoxidized Bio‐MnOx, Bio‐Ag0 and Ag+ separately did not show any removal capacity for diclofenac, an enhanced removal occurred when Bio‐MnOx and silver species were combined. Similar results were obtained for APA. Finally, a slow removal of diclofenac but more rapid APA degradation was observed when silver was added to manganese‐free P. putida biomass. Combining these results, three mechanisms of diclofenac and APA removal could be distinguished: (i) a co‐metabolic removal during active Mn2+ oxidation by P. putida; (ii) a synergistic interaction between preoxidized Bio‐MnOx and silver species; and (iii) a (bio)chemical process by biomass enriched with silver catalysts. This paper demonstrates the use of P. putida for water treatment purposes and is the first report of the application of silver combined with biogenic manganese for the removal of organic water contaminants. PMID:22221449

Green production of microalgae-based silver chloride nanoparticles with antimicrobial activity against pathogenic bacteria.

Science.gov (United States)

da Silva Ferreira, Veronica; ConzFerreira, Mateus Eugenio; Lima, Luís Maurício T R; Frasés, Susana; de Souza, Wanderley; Sant'Anna, Celso

2017-02-01

Silver nanoparticles are powerful antimicrobial agents. Here, the synthesis of silver chloride nanoparticles (AgCl-NPs) was consistently evidenced from a commercially valuable microalgae species, Chlorella vulgaris. Incubation of C. vulgaris conditioned medium with AgNO 3 resulted in a medium color change to yellow/brown (with UV-vis absorbance at 415nm), indicative of silver nanoparticle formation. Energy-dispersive X-ray spectroscopy (EDS) of purified nanoparticles confirmed the presence of both silver and chlorine atoms, and X-ray diffraction (XRD) showed the typical pattern of cubic crystalline AgCl-NPs. Transmission electron microscopy (TEM) showed that most particles (65%) were spherical, with average diameter of 9.8±5.7nm. Fourier transform infrared spectroscopy (FTIR) of purified nanoparticle fractions suggested that proteins are the main molecular entities involved in AgCl-NP formation and stabilization. AgCl-NPs (from 10μg/mL) decreased by 98% the growth of Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae bacterial pathogens, and had a dose-dependent effect on cell viability, which was measured by automated image-based high content screening (HCS). Ultrastructural analysis of treated bacteria by TEM revealed the abnormal arrangement of the chromosomal DNA. Our findings strongly indicated that the AgCl-NPs from C. vulgaris conditioned medium is a promising 'green' alternative for biomedical application as antimicrobials. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of silver nanoparticles on nitrification and associated nitrous oxide production in aquatic environments.

Science.gov (United States)

Zheng, Yanling; Hou, Lijun; Liu, Min; Newell, Silvia E; Yin, Guoyu; Yu, Chendi; Zhang, Hongli; Li, Xiaofei; Gao, Dengzhou; Gao, Juan; Wang, Rong; Liu, Cheng

2017-08-01

Silver nanoparticles (AgNPs) are the most common materials in nanotechnology-based consumer products globally. Because of the wide application of AgNPs, their potential environmental impact is currently a highly topical focus of concern. Nitrification is one of the processes in the nitrogen cycle most susceptible to AgNPs but the specific effects of AgNPs on nitrification in aquatic environments are not well understood. We report the influence of AgNPs on nitrification and associated nitrous oxide (N 2 O) production in estuarine sediments. AgNPs inhibited nitrification rates, which decreased exponentially with increasing AgNP concentrations. The response of nitrifier N 2 O production to AgNPs exhibited low-dose stimulation (production could be enhanced by >100% at low doses of AgNPs. This result was confirmed by metatranscriptome studies showing up-regulation of nitric oxide reductase (norQ) gene expression in the low-dose treatment. Isotopomer analysis revealed that hydroxylamine oxidation was the main N 2 O production pathway, and its contribution to N 2 O emission was enhanced when exposed to low-dose AgNPs. This study highlights the molecular underpinnings of the effects of AgNPs on nitrification activity and demonstrates that the release of AgNPs into the environment should be controlled because they interfere with nitrifying communities and stimulate N 2 O emission.

Antitumor activity of colloidal silver on MCF-7 human breast cancer cells.

Science.gov (United States)

Franco-Molina, Moisés A; Mendoza-Gamboa, Edgar; Sierra-Rivera, Crystel A; Gómez-Flores, Ricardo A; Zapata-Benavides, Pablo; Castillo-Tello, Paloma; Alcocer-González, Juan Manuel; Miranda-Hernández, Diana F; Tamez-Guerra, Reyes S; Rodríguez-Padilla, Cristina

2010-11-16

Colloidal silver has been used as an antimicrobial and disinfectant agent. However, there is scarce information on its antitumor potential. The aim of this study was to determine if colloidal silver had cytotoxic effects on MCF-7 breast cancer cells and its mechanism of cell death. MCF-7 breast cancer cells were treated with colloidal silver (ranged from 1.75 to 17.5 ng/mL) for 5 h at 37°C and 5% CO2 atmosphere. Cell Viability was evaluated by trypan blue exclusion method and the mechanism of cell death through detection of mono-oligonucleosomes using an ELISA kit and TUNEL assay. The production of NO, LDH, and Gpx, SOD, CAT, and Total antioxidant activities were evaluated by colorimetric assays. Colloidal silver had dose-dependent cytotoxic effect in MCF-7 breast cancer cells through induction of apoptosis, shown an LD50 (3.5 ng/mL) and LD100 (14 ng/mL) (*P colloidal silver. The present results showed that colloidal silver might be a potential alternative agent for human breast cancer therapy.

Mechanical, electrical, and thermal expansion properties of carbon nanotube-based silver and silver-palladium alloy composites

Science.gov (United States)

Pal, Hemant; Sharma, Vimal

2014-11-01

The mechanical, electrical, and thermal expansion properties of carbon nanotube (CNT)-based silver and silver-palladium (10:1, w/w) alloy nanocomposites are reported. To tailor the properties of silver, CNTs were incorporated into a silver matrix by a modified molecular level-mixing process. CNTs interact weakly with silver because of their non-reactive nature and lack of mutual solubility. Therefore, palladium was utilized as an alloying element to improve interfacial adhesion. Comparative microstructural characterizations and property evaluations of the nanocomposites were performed. The structural characterizations revealed that decorated type-CNTs were dispersed, embedded, and anchored into the silver matrix. The experimental results indicated that the modification of the silver and silver-palladium nanocomposite with CNT resulted in increases in the hardness and Young's modulus along with concomitant decreases in the electrical conductivity and the coefficient of thermal expansion (CTE). The hardness and Young's modulus of the nanocomposites were increased by 30%-40% whereas the CTE was decreased to 50%-60% of the CTE of silver. The significantly improved CTE and the mechanical properties of the CNT-reinforced silver and silver-palladium nanocomposites are correlated with the intriguing properties of CNTs and with good interfacial adhesion between the CNTs and silver as a result of the fabrication process and the contact action of palladium as an alloying element.

Silver Nanoparticles and Graphitic Carbon Through Thermal Decomposition of a Silver/Acetylenedicarboxylic Salt

Directory of Open Access Journals (Sweden)

Komninou Philomela

2009-01-01

Full Text Available Abstract Spherically shaped silver nanoparticles embedded in a carbon matrix were synthesized by thermal decomposition of a Ag(I/acetylenedicarboxylic acid salt. The silver nanoparticles, which are formed either by pyrolysis at 300 °C in an autoclave or thermolysis in xylene suspension at reflux temperature, are acting catalytically for the formation of graphite layers. Both reactions proceed through in situ reduction of the silver cations and polymerization of the central acetylene triple bonds and the exact temperature of the reaction can be monitored through DTA analysis. Interestingly, the thermal decomposition of this silver salt in xylene partly leads to a minor fraction of quasicrystalline silver, as established by HR-TEM analysis. The graphitic layers covering the silver nanoparticles are clearly seen in HR-TEM images and, furthermore, established by the presence of sp2carbon at the Raman spectrum of both samples.

Regulatory considerations concerning IND radiopharmaceutical drug products

International Nuclear Information System (INIS)

Nissel, M.

1985-01-01

The Food and Drug Administration is charged by the Food, Drug, and Cosmetic Act, as presently amended, to assure that any drug introduced into interstate commerce is safe and effective for the purposes for which it is labeled. A radiopharmaceutical is, by definition, a new drug unless there is in effect an approved New Drug Application (NDA) for it. Before the data for the NDA are compiled, investigative studies have to be done. Before such studies can be performed in humans, an exemption from the Act is necessary. This exemption, technically the Claimed Exemption for an Investigational New Drug, is termed the IND. Both the scientific and the administrative requirements for an IND are discussed. For radiopharmaceutical drug products (RDP's), the radiation hazards, as well as the pharmacological ones, must be documented. Should the early studies demonstrate a potential for efficacy in a certain condition or disease state, an investigative protocol for an extended clinical trial is presented. The necessary requirements for Institutional Review Board (IRB) approval and consent forms are discussed. For certain research purposes, uniquely for radioactive drugs, an IND is not required for certain specific studies; the requirements for such a research study, conducted under the auspices of an approved radioactive drug research committee, are outlined

Development of nanostructured silver vanadates decorated with silver nanoparticles as a novel antibacterial agent

Energy Technology Data Exchange (ETDEWEB)

Holtz, R D; Souza Filho, A G; Alves, O L [Laboratorio de Quimica do Estado Solido (LQES), Instituto de Quimica, Universidade Estadual de Campinas, CP 6154, 13081-970, Campinas-SP (Brazil); Brocchi, M; Martins, D [Departamento de Genetica, Evolucao and Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Campinas-SP (Brazil); Duran, N, E-mail: rholtz@iqm.unicamp.br, E-mail: agsf@fisica.ufc.br, E-mail: oalves@iqm.unicamp.br [Laboratorio de Quimica Biologica, Instituto de Quimica, Universidade Estadual de Campinas, Campinas-SP (Brazil)

2010-05-07

In this work we report the synthesis, characterization and application of silver vanadate nanowires decorated with silver nanoparticles as a novel antibacterial agent. These hybrid materials were synthesized by a precipitation reaction of ammonium vanadate and silver nitrate followed by hydrothermal treatment. The silver vanadate nanowires have lengths of the order of microns and diameters around 60 nm. The silver nanoparticles decorating the nanowires present a diameter distribution varying from 1 to 20 nm. The influence of the pH of the reaction medium on the chemical structure and morphology of silver vanadates was studied and we found that synthesis performed at pH 5.5-6.0 led to silver vanadate nanowires with a higher morphological yield. The antimicrobial activity of these materials was evaluated against three strains of Staphylococcus aureus and very promising results were found. The minimum growth inhibiting concentration value against a MRSA strain was found to be ten folds lower than for the antibiotic oxacillin.

Special Resins for Stereolithography: In Situ Generation of Silver Nanoparticles

Directory of Open Access Journals (Sweden)

Gabriele Taormina

2018-02-01

Full Text Available The limited availability of materials with special properties represents one of the main limitations to a wider application of polymer-based additive manufacturing technologies. Filled resins are usually not suitable for vat photo-polymerization techniques such as stereolithography (SLA or digital light processing (DLP due to a strong increment of viscosity derived from the presence of rigid particles within the reactive suspension. In the present paper, the possibility to in situ generate silver nanoparticles (AgNPs starting from a homogeneous liquid system containing a well dispersed silver salt, which is subsequently reduced to metallic silver during stereolithographic process, is reported. The simultaneous photo-induced cross-linking of the acrylic resin produces a filled thermoset resin with thermal-mechanical properties significantly enhanced with respect to the unfilled resin, even at very low AgNPs concentrations. With this approach, the use of silver salts having carbon-carbon double bonds, such as silver acrylate and silver methacrylate, allows the formation of a nanocomposite structure in which the release of by-products is minimized due to the active role of all the reactive components in the three dimensional (3D-printing processes. The synergy, between this nano-technology and the geometrical freedom offered by SLA, could open up a wide spectrum of potential applications for such a material, for example in the field of food packaging and medical and healthcare sectors, considering the well-known antimicrobial effects of silver nanoparticles.

75 FR 73108 - Guidance for Industry on Abbreviated New Drug Applications: Impurities in Drug Products...

Science.gov (United States)

2010-11-29

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2010-D-0584... Products.'' This guidance updates recommendations regarding degradation products and updates the draft... information on listing of degradation products, setting acceptance criteria, and qualifying degradation...

One-step synthesis and antibacterial property of water-soluble silver nanoparticles by CGJ bio-template

International Nuclear Information System (INIS)

Zhu Zichun; Wu Qingsheng; Chen Ping; Yang Xiaohong

2011-01-01

In this article, a new synthetic method of nanoparticles with fresh Chinese gooseberry juice (CGJ) as bio-template was developed. One-step synthesis of highly water-soluble silver nanoparticles at room temperature without using any harmful reducing agents and special capping agent was fulfilled with this method. In the process, the products were obtained by adding AgNO 3 to CGJ, which was used as reducing agent, capping agent, and the bio-template. The products of silver nanoparticles with diameter of 10–30 nm have strong water solubility and excellent antibiotic function. With the same concentration 0.047 μg mL −1 , the antibacterial effect of water-soluble silver particles by fresh CGJ was 53%, whereas only 27% for silver nanoparticles synthesized using the template method of fresh onion inner squama coat (OISC). The excellent water solubility of the products would enable them have better applications in the bio-medical field. The synthetic method would also have potential application in preparing other highly water-soluble particles, because of its simple apparatus, high yield, mild conditions, and facile operation.

Biopolymer mediated nanoparticles synthesized from Adenia hondala for enhanced tamoxifen drug delivery in breast cancer cell line

Science.gov (United States)

Varadharajaperumal, Pradeepa; Subramanian, Balakumar; Santhanam, Amutha

2017-09-01

Silver nanoparticles (AgNPs) are an important class of nanomaterials, which have used as antimicrobial and disinfectant agents due to their detrimental effect on target cells. In the present study it was explored to deliver a novel tamoxifen drug system that can be used in breast cancer treatment, based on chitosan coated silver nanoparticles on MCF-7 human breast cancer cells. AgNPs synthesized from Adenia hondala tuber extract were used to make the chitosan coated AgNPs (Ch-AgNPs), in which the drug tamoxifen was loaded on chitosan coated silver nanoparticles (Tam-Ch-AgNPs) to construct drug loaded nanoparticles as drug delivery system. The morphology and characteristics of the Ch-AgNPs were investigated by UV, FTIR, zeta potential and FESEM. Furthermore, the toxicity of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs was evaluated through cell viability, lactate dehydrogenase leakage, reactive oxygen species generation, caspase-3, DNA laddering, and TUNEL assay in human breast cancer cells (MCF-7) and HBL-100 continuous cell line as a control. Treatment of cancer cells with various concentrations of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs for 24 h revealed that Tam-Ch-AgNPs could inhibit cell viability and induce significant membrane leakage in a dose-dependent manner. Cells exposed to Tam-Ch-AgNPs showed increased reactive oxygen species and hydroxyl radical production when compared to AgNPs, Ch-AgNPs. Furthermore, the apoptotic effects of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs were confirmed by activation of caspase-3 and DNA nuclear fragmentation. The present findings suggest that Tam-Ch-AgNPs could contribute to the development of a suitable anticancer drug delivery.

The Synthesis of Silver Nanoparticles Produced by Chemical Reduction of Silver Salt Solution

International Nuclear Information System (INIS)

Sri Budi Harmani; Dewi Sondari; Agus Haryono

2008-01-01

Described in this research are the synthesis of silver nanoparticle produced by chemical reduction of silver salt (silver nitrate AgNO 3 ) solution. As a reducer, sodium citrate (C 6 H 5 O 7 Na 3 ) was used. Preparation of silver colloid is done by using chemical reduction method. In typical experiment 150 ml of 1.10 -3 M AgNO 3 solution was heated with temperature variation such as 90, 100, 110 degree of Celsius. To this solution 15 ml of 1 % trisodium citrate was added into solution drop by drop during heating. During the process, solution was mixed vigorously. Solution was heated until colour's change is evident (pale yellow solution is formed). Then it was removed from the heating element and stirred until cooled to room temperature. Experimental result showed that diameter of silver nanoparticles in colloid solution is about 28.3 nm (Ag colloid, 90 o C); 19.9 nm (Ag colloid, 100 o C)and 26.4 nm (Ag colloid, 110 o C). Characterization of the silver nanoparticle colloid conducted by using UV-Vis Spectroscopy, Particles Size Analyzer (PSA) and Scanning Electron Microscope (SEM) indicate the produced structures of silver nanoparticles. (author)

21 CFR 20.2 - Production of records by Food and Drug Administration employees.

Science.gov (United States)

2010-04-01

... upon an officer or employee of the Food and Drug Administration commanding the production of any record... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Production of records by Food and Drug Administration employees. 20.2 Section 20.2 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

Studies on the antimicrobial properties of colloidal silver nanoparticles stabilized by bovine serum albumin.

Science.gov (United States)

Mathew, Thomas V; Kuriakose, Sunny

2013-01-01

Colloidal silver nanoparticles were synthesised using sol-gel method and these nanoparticles were stabilised by encapsulated into the scaffolds of bovine serum albumin. Silver nanoparticles and encapsulated products were characterised by FTIR, NMR, XRD, TG, SEM and TEM analyses. Silver nanoparticle encapsulated bovine serum albumin showed highly potent antibacterial activity towards the bacterial strains such as Staphylococcus aureus, Serratia marcescens, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae. Copyright © 2012 Elsevier B.V. All rights reserved.

Graphene Oxide-Based Nanocomposites Decorated with Silver Nanoparticles as an Antibacterial Agent

Science.gov (United States)

Jaworski, Sławomir; Wierzbicki, Mateusz; Sawosz, Ewa; Jung, Anna; Gielerak, Grzegorz; Biernat, Joanna; Jaremek, Henryk; Łojkowski, Witold; Woźniak, Bartosz; Wojnarowicz, Jacek; Stobiński, Leszek; Małolepszy, Artur; Mazurkiewicz-Pawlicka, Marta; Łojkowski, Maciej; Kurantowicz, Natalia; Chwalibog, André

2018-04-01

One of the most promising methods against drug-resistant bacteria can be surface-modified materials with biocidal nanoparticles and nanocomposites. Herein, we present a nanocomposite with silver nanoparticles (Ag-NPs) on the surface of graphene oxide (GO) as a novel multifunctional antibacterial and antifungal material. Ultrasonic technologies have been used as an effective method of coating polyurethane foils. Toxicity on gram-negative bacteria ( Escherichia coli), gram-positive bacteria ( Staphylococcus aureus and Staphylococcus epidermidis), and pathogenic yeast ( Candida albicans) was evaluated by analysis of cell morphology, assessment of cell viability using the PrestoBlue assay, analysis of cell membrane integrity using the lactate dehydrogenase assay, and reactive oxygen species production. Compared to Ag-NPs and GO, which have been widely used as antibacterial agents, our nanocomposite shows much higher antimicrobial efficiency toward bacteria and yeast cells.

Nano-sized crystalline drug production by milling technology.

Science.gov (United States)

Moribe, Kunikazu; Ueda, Keisuke; Limwikrant, Waree; Higashi, Kenjirou; Yamamoto, Keiji

2013-01-01

Nano-formulation of poorly water-soluble drugs has been developed to enhance drug dissolution. In this review, we introduce nano-milling technology described in recently published papers. Factors affecting the size of drug crystals are compared based on the preparation methods and drug and excipient types. A top-down approach using the comminution process is a method conventionally used to prepare crystalline drug nanoparticles. Wet milling using media is well studied and several wet-milled drug formulations are now on the market. Several trials on drug nanosuspension preparation using different apparatuses, materials, and conditions have been reported. Wet milling using a high-pressure homogenizer is another alternative to preparing production-scale drug nanosuspensions. Dry milling is a simple method of preparing a solid-state drug nano-formulation. The effect of size on the dissolution of a drug from nanoparticles is an area of fundamental research, but it is sometimes incorrectly evaluated. Here, we discuss evaluation procedures and the associated problems. Lastly, the importance of quality control, process optimization, and physicochemical characterization are briefly discussed.

Bullion to B-fields: The Silver Program of the Manhattan Project

Science.gov (United States)

Reed, Cameron

2010-04-01

Between October 1942 and September 1944, over 14,000 tons of silver bullion bars withdrawn form the U.S. Treasury were melted and cast into magnet coils and busbar pieces for the ``calutron'' electromagnetic isotope-separators constructed at Oak Ridge. Based on Manhattan Engineer District documents, this paper will review the history of this ``Silver Program,'' including discussions of the contractors, production methods, and quantities of materials involved.

75 FR 33312 - Indexing Structured Product Labeling for Human Prescription Drug and Biological Products; Request...

Science.gov (United States)

2010-06-11

...] Indexing Structured Product Labeling for Human Prescription Drug and Biological Products; Request for... Biologics Evaluation and Research (CBER) are indexing certain categories of information in product labeling for use as terms to search repositories of approved prescription medical product structured product...

[Morphological changes of the intestine in experimental acute intestinal infection in the treatment of colloidal silver].

Science.gov (United States)

Polov'ian, E S; Chemich, N D; Moskalenko, R A; Romaniuk, A N

2012-06-01

At the present stage of infectionist practice in the treatment of acute intestinal infections caused by opportunistic microorganisms, colloidal silver is used with a particle size of 25 nm as an alternative to conventional causal therapy. In 32 rats, distributed in 4 groups of 8 animals each (intact; healthy, got colloidal silver; with a modeled acute intestinal infection in the basic treatment and with the addition of colloidal silver), histological examination was performed of small and large intestine of rats. Oral administration of colloidal silver at a dose of 0.02 mg/day to intact rats did not lead to changes in morphometric parameters compared to the norm, and during early convalescence in rats with acute intestinal infections were observed destructive and compensatory changes in the intestine, which depended on the treatment regimen. With the introduction of colloidal silver decreased activity of the inflammatory process and the severity of morphological changes in tissues of small and large intestine, indicating that the positive effect of study drug compared with baseline therapy.

Synthesis and anticancer activity of silver(I)-N-heterocyclic carbene complexes derived from the natural xanthine products caffeine, theophylline and theobromine.

Science.gov (United States)

Mohamed, Heba A; Lake, Benjamin R M; Laing, Thomas; Phillips, Roger M; Willans, Charlotte E

2015-04-28

A new library of silver(I)-N-heterocyclic carbene complexes prepared from the natural products caffeine, theophylline and theobromine is reported. The complexes have been fully characterised using a combination of NMR spectroscopy, mass spectrometry, elemental analysis and X-ray diffraction analysis. Furthermore, the hydrophobicity of the complexes has been measured. The silver(I)-N-heterocyclic carbenes have been evaluated for their antiproliferative properties against a range of cancer cell lines of different histological types, and compared to cisplatin. The data shows different profiles of response when compared to cisplatin in the same panel of cells, indicating a different mechanism of action. Furthermore, it appears that the steric effect of the ligand and the hydrophobicity of the complex both play a role in the chemosensitivity of these compounds, with greater steric bulk and greater hydrophilicity delivering higher cytotoxicity.

Fabrication Of Biogenic Silver Nanoparticles Using Agricultural Crop Plant Leaf Extracts

Science.gov (United States)

Rajani, P.; SriSindhura, K.; Prasad, T. N. V. K. V.; Hussain, O. M.; Sudhakar, P.; Latha, P.; Balakrishna, M.; Kambala, V.; Reddy, K. Raja

2010-10-01

Nanoparticles are being viewed as fundamental building blocks of nanotechnology. Biosynthesis of nanoparticles by plant extracts is currently under exploitation. Use of agricultural crop plant extracts for synthesis of metal nanoparticles would add a new dimension to the agricultural sector in the utilization of crop waste. Silver has long been recognized as having an inhibitory effect towards many bacterial strains and microorganisms commonly present in medical and industrial processes. Four pulse crop plants and three cereal crop plants (Vigna radiata, Arachis hypogaea, Cyamopsis tetragonolobus, Zea mays, Pennisetum glaucum, Sorghum vulgare) were used and compared for their extra cellular synthesis of metallic silver nanoparticles. Stable silver nanoparticles were formed by treating aqueous solution of AgNO3 with the plant leaf extracts as reducing agent at temperatures 50 °C-95 °C. UV-Visible spectroscopy was utilized to monitor the formation of silver nanoparticles. XRD analysis of formed silver nanoparticles revealed face centered cubic structure with (111), (200), (220) and (311) planes. SEM and EDAX analysis confirm the size of the formed silver nanoparticles to be in the range of 50-200 nm. Our proposed work offers a enviro-friendly method for biogenic silver nanoparticles production. This could provide a faster synthesis rate comparable to those of chemical methods and potentially be used in areas such as cosmetics, food and medical applications.

Mechanistic aspects of biosynthesis of silver nanoparticles by several Fusarium oxysporum strains

Directory of Open Access Journals (Sweden)

De Souza Gabriel IH

2005-07-01

Full Text Available Abstract Extracellular production of metal nanoparticles by several strains of the fungus Fusarium oxysporum was carried out. It was found that aqueous silver ions when exposed to several Fusarium oxysporum strains are reduced in solution, thereby leading to the formation of silver hydrosol. The silver nanoparticles were in the range of 20–50 nm in dimensions. The reduction of the metal ions occurs by a nitrate-dependent reductase and a shuttle quinone extracellular process. The potentialities of this nanotechnological design based in fugal biosynthesis of nanoparticles for several technical applications are important, including their high potential as antibacterial material.

The influence of seeding conditions and shielding gas atmosphere on the synthesis of silver nanowires through the polyol process

Science.gov (United States)

Chen, Chang; Wang, Li; Jiang, Guohua; Yang, Qiang; Wang, Jianjun; Yu, Haojie; Chen, Tao; Wang, Chiliang; Chen, Xu

2006-01-01

The polyol process including the introduction of preformed seeds and the inducement of poly(vinyl pyrrolidone) (PVP) has been developed as a powerful approach for synthesizing silver nanowires. Here, silver nanowires without other metal elements as impurities were synthesized through a silver seeding polyol process in a shielding gas atmosphere. It is demonstrated that the first seeding step is critical in obtaining silver nanowires as the principal product, and we also observe that the shielding gas atmosphere not only improves the repeatability of experiments but also affects the morphology of the final product. We obtained nanocubes with hydrogen gas shielding in a short reaction time; these would scarcely appear with argon or air shielding. Our work supplies new evidence to explain the actual growth mechanism of silver nanowires.

Green synthesis, characterization of gold and silver nanoparticles and their potential application for cancer therapeutics

International Nuclear Information System (INIS)

Patra, Sujata; Mukherjee, Sudip; Barui, Ayan Kumar; Ganguly, Anirban; Sreedhar, Bojja; Patra, Chitta Ranjan

2015-01-01

In the present article, we demonstrate the delivery of anti-cancer drug to the cancer cells using biosynthesized gold and silver nanoparticles (b-AuNP & b-AgNP). The nanoparticles synthesized by using Butea monosperma (BM) leaf extract are thoroughly characterized by various analytical techniques. Both b-AuNP and b-AgNP are stable in biological buffers and biocompatible towards normal endothelial cells (HUVEC, ECV-304) as well as cancer cell lines (B16F10, MCF-7, HNGC2 & A549). Administration of nanoparticle based drug delivery systems (DDSs) using doxorubicin (DOX) [b-Au-500-DOX and b-Ag-750-DOX] shows significant inhibition of cancer cell proliferation (B16F10, MCF-7) compared to pristine drug. Therefore, we strongly believe that biosynthesized nanoparticles will be useful for the development of cancer therapy using nanomedicine approach in near future. - Highlights: • Biosynthesis of gold and silver nanoparticles using plant leaf extract • The approach is clean, efficient, eco-friendly & economically safe. • Biosynthesized nanoparticles are biocompatible towards normal and cancer cells. • Design and development of biosynthesized nanoparticle based drug delivery systems • Biosynthesized nanoparticles could be useful for cancer and other diseases

Green synthesis, characterization of gold and silver nanoparticles and their potential application for cancer therapeutics

Energy Technology Data Exchange (ETDEWEB)

Patra, Sujata; Mukherjee, Sudip; Barui, Ayan Kumar; Ganguly, Anirban [Biomaterials Group, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, Telangana State (India); Sreedhar, Bojja [Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, Telangana State (India); Patra, Chitta Ranjan, E-mail: crpatra@iict.res.in [Biomaterials Group, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, Telangana State (India)

2015-08-01

In the present article, we demonstrate the delivery of anti-cancer drug to the cancer cells using biosynthesized gold and silver nanoparticles (b-AuNP & b-AgNP). The nanoparticles synthesized by using Butea monosperma (BM) leaf extract are thoroughly characterized by various analytical techniques. Both b-AuNP and b-AgNP are stable in biological buffers and biocompatible towards normal endothelial cells (HUVEC, ECV-304) as well as cancer cell lines (B16F10, MCF-7, HNGC2 & A549). Administration of nanoparticle based drug delivery systems (DDSs) using doxorubicin (DOX) [b-Au-500-DOX and b-Ag-750-DOX] shows significant inhibition of cancer cell proliferation (B16F10, MCF-7) compared to pristine drug. Therefore, we strongly believe that biosynthesized nanoparticles will be useful for the development of cancer therapy using nanomedicine approach in near future. - Highlights: • Biosynthesis of gold and silver nanoparticles using plant leaf extract • The approach is clean, efficient, eco-friendly & economically safe. • Biosynthesized nanoparticles are biocompatible towards normal and cancer cells. • Design and development of biosynthesized nanoparticle based drug delivery systems • Biosynthesized nanoparticles could be useful for cancer and other diseases.

SERS investigations on orientation of 2-bromo-3-methyl-1,4-dimethoxy-9,10-anthraquinone on silver nanoparticles.

Science.gov (United States)

Anuratha, M; Jawahar, A; Umadevi, M; Sathe, V G; Vanelle, P; Terme, T; Khoumeri, O; Meenakumari, V; Milton Franklin Benial, A

2015-01-01

Silver nanoparticles (Ag NPs) were prepared by solution combustion method with urea as fuel. Silver nanoparticles were characterized by UV-visible spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Surface-enhanced Raman scattering (SERS) of 2-bromo-3-methyl-1,4-dimethoxy-9,10-anthraquinone (BMDMAQ) adsorbed on silver nanoparticles was investigated. The orientation of BMDMAQ on silver nanoparticles was inferred from nRs and SERS spectral features. Density functional theory (DFT) calculation was also performed to study the theoretical performance. The observed spectral features such as the high intensity of C-H out-of-plane bending mode and ring C-C stretching mode revealed that BMDMAQ adsorbed on silver surface through 'stand-on' orientation. Anthraquinone (AQ) derivatives have wide biomedical application which includes laxatives, antimalarials and antineoplastics used in the treatment of cancer. This present study would help to identify the interaction of drug molecules with DNA. Copyright © 2015 Elsevier B.V. All rights reserved.

Relaxation of the silver/silver iodide electrode in aqueous solution

NARCIS (Netherlands)

Peverelli, K.J.

1979-01-01

The aim of this study is to detect and characterize relaxation processes on silver/silver iodide electrodes in aqueous electrolyte solution. The information obtained is to be used for an estimation of the consequences of similar processes on colloidal AgI

Production of porous filter elements from PEUAPM nanocomposites and silver nanoparticles; Producao de elementos filtrantes porosos a partir de nanocompositos de PEUAPM e nanoparticulas de prata

Energy Technology Data Exchange (ETDEWEB)

Bizzo, M.A.; Hui, W.S., E-mail: mbizzo@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Departamento de Engenharia Metalurgica e de Materiais

2014-07-01

The production of filter elements for water based in polymers is widespread in the market, but has an undesirable characteristic: they are not efficient and able to retain or eliminate microorganisms at all times. This paper proposes to produce nanocomposite filters with biocidal properties composed of ultra-high molecular weight polyethylene(UHMWPE) and silver nanoparticles, the UHMWPE is responsible for the uniform porous structure of the filters and the silver nanoparticles incorporated on the polymer are responsible for the biocide action. Particulate polymer that presents a different particle size curve was used for sintering the filters. Samples of filter elements obtained in this work were characterized by the techniques of X-ray diffraction, scanning electron microscopy and EDS microanalysis. The results indicated a porosity of approximately 49% in the filter, and the formation of the nanocomposite. key-words: nanocomposites, silver, UHMWPE, filter elements. (author)

Isatis tinctoria mediated synthesis of amphotericin B-bound silver nanoparticles with enhanced photoinduced antileishmanial activity: A novel green approach.

Science.gov (United States)

Ahmad, Aftab; Wei, Yun; Syed, Fatima; Khan, Shafiullah; Khan, Gul Majid; Tahir, Kamran; Khan, Arif Ullah; Raza, Muslim; Khan, Faheem Ullah; Yuan, Qiping

2016-08-01

After malaria, Leishmaniasis is the most prevalent infectious disease in terms of fatality and geographical distribution. The availability of a limited number of antileishmanial agents, emerging resistance to the available drugs, and the high cost of treatment complicate the treatment of leishmaniasis. To overcome these issues, critical research for new therapeutic agents with enhanced antileishmanial potential and low treatment cost is needed. In this contribution, we developed a green protocol to prepare biogenic silver nanoparticles (AgNPs) and amphotericin B-bound biogenic silver nanoparticles (AmB-AgNPs). Phytochemicals from the aqueous extract of Isatis tinctoria were used as reducing and capping agents to prepare silver nanoparticles. Amphotericin B was successfully adsorbed on the surface of biogenic silver nanoparticles. The prepared nanoparticles were characterized by various analytical techniques. UV-Visible spectroscopy was employed to detect the characteristic localized surface plasmon resonance peaks (LSPR) for the prepared nanoparticles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) studies revealed the formation of spherical silver nanoparticles with an average particle size of 10-20nm. The cubic crystalline structure of the prepared nanoparticles was confirmed by X-ray diffraction (XRD) study. FTIR spectroscopic analysis revealed that plant polyphenolic compounds are mainly involved in metal reduction and capping. Under visible light irradiation, biogenic silver nanoparticles exhibited significant activity against Leishmania tropica with an IC50 value of 4.2μg/mL. The leishmanicidal activity of these nanoparticles was considerably enhanced by conjugation with amphotericin B (IC50=2.43μg/mL). In conclusion, the findings of this study reveal that adsorption of amphotericin B, an antileishmanial drug, to biogenic silver nanoparticles, could be a safe, more effective and economic alternative to the available

Silver chromate and silver dichromate nanostructures: Sonochemical synthesis, characterization, and photocatalytic properties

Energy Technology Data Exchange (ETDEWEB)

Soofivand, Faezeh [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Mohandes, Fatemeh [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of)

2013-06-01

Graphical abstract: In this work, Ag{sub 2}CrO{sub 4} and Ag{sub 2}Cr{sub 2}O{sub 7} nanostructures have been sonochemically prepared using silver salicylate. The effect of preparation parameters on the morphology of the products was investigated by SEM images. Highlights: ► Herein, Ag{sub 2}CrO{sub 4} and Ag{sub 2}Cr{sub 2}O{sub 7} nanostructures have been sonochemically prepared. ► The effect of preparation parameters on the morphology of the products was investigated. ► The photocatalytic activity of the as-prepared Ag{sub 2}CrO{sub 4} nanoparticles was tested. ► XPS spectra indicated the high purity of Ag{sub 2}Cr{sub 2}O{sub 7} nanostructures obtained. - Abstract: In this work, Ag{sub 2}CrO{sub 4} and Ag{sub 2}Cr{sub 2}O{sub 7} nanostructures have been produced via a sonochemical method using silver salicylate as precursor. Besides silver salicylate, Na{sub 2}CrO{sub 4} and (NH{sub 4}){sub 2}Cr{sub 2}O{sub 7} as starting reagents were applied. To investigate the effect of preparation parameters on the morphology and particle size of Ag{sub 2}CrO{sub 4} and Ag{sub 2}Cr{sub 2}O{sub 7}, sonication time, type of surfactant and its concentration were changed. The as-produced nanostructures were characterized by techniques like powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The scanning electron micrographs showed that particle-like and rod-like nanostructures of Ag{sub 2}CrO{sub 4} and Ag{sub 2}Cr{sub 2}O{sub 7} were produced using different surfactants. To investigate the catalytic properties of Ag{sub 2}CrO{sub 4} nanoparticles, photooxidation of methyl orange (MO) was performed. According to the obtained results, it was found that the methyl orange degradation was about 87.3% after 280 min irradiation of visible light.

Rapid preparation process of antiparkinsonian drug Mucuna pruriens silver nanoparticle by bioreduction and their characterization

Science.gov (United States)

Arulkumar, Subramanian; Sabesan, Muthukumaran

2010-01-01

Backgorund: Development of biologically inspired experimental processes for the synthesis of nanoparticles is evolving an important branch of nanotechnology. Methods: The bioreduction behavior of plant seed extract of Mucuna pruriens in the synthesis of silver nanoparticles was investigated employing UV/visible spectrophotometry, X-ray diffraction (XRD), and transmission electron microscopy (TEM), Fourier transform – infra red (FT- IR). Result: M. pruriens was found to exhibit strong potential for rapid reduction of silver ions. The formation of nanoparticles by this method is extremely rapid, requires no toxic chemicals, and the nanoparticles are stable for several months. Conclusion: The main conclusion is that the bioreduction method to produce nanoparticles is a good alternative to the electrochemical methods and it is expected to be biocompatible. PMID:21808573

Sponge-like silver obtained by decomposition of silver nitrate hexamethylenetetramine complex

International Nuclear Information System (INIS)

Afanasiev, Pavel

2016-01-01

Silver nitrate hexamethylenetetramine [Ag(NO 3 )·N 4 (CH 2 ) 6 ] coordination compound has been prepared via aqueous route and characterized by chemical analysis, XRD and electron microscopy. Decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] under hydrogen and under inert has been studied by thermal analysis and mass spectrometry. Thermal decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] proceeds in the range 200–250 °C as a self-propagating rapid redox process accompanied with the release of multiple gases. The decomposition leads to formation of sponge-like silver having hierarchical open pore system with pore size spanning from 10 µm to 10 nm. The as-obtained silver sponges exhibited favorable activity toward H 2 O 2 electrochemical reduction, making them potentially interesting as non-enzyme hydrogen peroxide sensors. - Graphical abstract: Thermal decomposition of silver nitrate hexamethylenetetramine coordination compound [Ag(NO 3 )·N 4 (CH 2 ) 6 ] leads to sponge like silver that possesses open porous structure and demonstrates interesting properties as an electrochemical hydrogen peroxide sensor. Display Omitted - Highlights: • [Ag(NO 3 )·N 4 (CH 2 ) 6 ] orthorhombic phase prepared and characterized. • Decomposition of [Ag(NO 3 )·N 4 (CH 2 ) 6 ] leads to metallic silver sponge with opened porosity. • Ag sponge showed promising properties as a material for hydrogen peroxide sensors.

78 FR 75570 - Guidance for Industry on New Animal Drugs and New Animal Drug Combination Products Administered...

Science.gov (United States)

2013-12-12

... Guidance for Industry (GFI) 209, ``The Judicious Use of Medically Important Antimicrobial Drugs in Food... of certain antimicrobial new animal drug products who are interested in revising conditions of use... Medically Important Antimicrobial Drugs in Food-Producing Animals,'' and to set timelines for stakeholders...

75 FR 65565 - Animal Drugs, Feeds, and Related Products; Withdrawal of Approval of New Animal Drug Applications...

Science.gov (United States)

2010-10-26

... 558 [Docket No. FDA-2010-N-0002] Animal Drugs, Feeds, and Related Products; Withdrawal of Approval of New Animal Drug Applications; Aklomide; Levamisole Hydrochloride; Nitromide and Sulfanitran AGENCY...) is amending the animal drug regulations by removing those portions that reflect approval of eight new...

Chemical recovery of palladium-103 from irradiated silver target

International Nuclear Information System (INIS)

Lapshina, E.V.; Kokhanyuk, V.M.; Zhuikov, B.L.; Myasoedova, G.V.; Zakhartchenko, E.A.; Phillips, D.R.; Jamriska, D.J.

2003-01-01

The goal of this work is to develop an extraction method of no-carrier-added palladium-103 from silver. Metallic silver targets may be irradiated by protons with energy of 60-200 MeV or more to generate palladium-103 simultaneously with other radioactive isotopes of rhodium, ruthenium, technetium, palladium and silver. According to the dependence experimental production yield of Pd-103 and isotopes of other elements in thick silver target vs. Proton energy the most suitable energy for maximum yield of Pd-103 and minimum yield of other elements is from about 100 to about 140 MeV. Activity of radionuclides produced in silver target depends from many factors (target thickness, irradiation time, etc.). Two methods of Pd-103 recovering from irradiated silver target are considered in this work: (1) Silver target is dissolved in nitric acid followed by silver precipitation in the form of silver chloride by addition of HCl. The solution containing Pd, Rh and other radionuclides is passed through the layer of fibrous sorbent POLYORGS-15n. Then the sorbent is washed and Pd is desorbed by hot 12 M hydrochloric acid; (2) Silver target is dissolved in nitric acid followed by passing of the obtained solution (2 M HNO 3 ) through a disk set of complex forming sorbent POLYORGS-33n. Under these conditions palladium is sorbed by the sorbent while silver, rhodium, ruthenium and technetium are passed through the sorbent. Then the sorbent is washed with 2M nitric acid, and Pd is desorbed by 12 M hydrochloric acid. Extraction of palladium is occurred during the formation of palladium complex with a chelate sorbent specific to palladium in acidic solutions. Such a sorbent makes possible separation of palladium from accompanying radionuclides such as rhodium, ruthenium and technetium. The polymeric complex-forming sorbent of fibrous structure with the groups of 3(5)-methylpyrazole (POLYORGS-15) is used. The distinctive feature of the sorbents in the form of fibrous 'filled' material is

Franklin D. Roosevelt, Silver, and China.

OpenAIRE

Friedman, Milton

1992-01-01

The silver purchase program, initiated by Franklin Roosevelt in late 1933 in response to the economically small but politically potent silver bloc, gave a large short-run subsidy to silver producers at the cost of destroying any long-run monetary role for silver. More important, it imposed severe deflation on China, the only major country still on a silver standard, and forced it off the silver standard and on to a fiat standard, which brought forward in time and increased in severity the sub...

Interactive Relationship between Silver Ions and Silver Nanoparticles with PVA Prepared by the Submerged Arc Discharge Method

Directory of Open Access Journals (Sweden)

Kuo-Hsiung Tseng

2018-01-01

Full Text Available This study uses the submerged arc discharge method (SADM and the concentrated energy of arc to melt silver metal in deionized water (DW so as to prepare metal fluid with nanoparticles and submicron particles. The process is free from any chemical agent; it is rapid and simple, and rapid and mass production is available (0.5 L/min. Aside from the silver nanoparticle (Ag0, silver ions (Ag+ exist in the colloidal Ag prepared by the system. In the preparation of colloidal Ag, polyvinyl alcohol (PVA is used as an additive so that the Ag0/Ag+ concentration, arcing rate, peak, and scanning electron microscopic (SEM images in the cases with and without PVA can be analyzed. The findings show that the Ag0/Ag+ concentration increases with the addition level of PVA, while the nano-Ag and Ag+ electrode arcing rate rises. The UV-Vis absorption peak increases Ag0 absorbance and shifts as the dispersity increases with PVA addition. Lastly, with PVA addition, the proposed method can prepare smaller and more amounts of Ag0 nanoparticles, distributed uniformly. PVA possesses many distinct features such as cladding, dispersion, and stability.

Effect of Accelerator in Green Synthesis of Silver Nanoparticles

Directory of Open Access Journals (Sweden)

Kamyar Shameli

2010-10-01

Full Text Available Silver nanoparticles (Ag-NPs were successfully synthesized in the natural polymeric matrix. Silver nitrate, gelatin, glucose, and sodium hydroxide have been used as silver precursor, stabilizer, reducing agent, and accelerator reagent, respectively. This study investigated the role of NaOH as the accelerator. The resultant products have been confirmed to be Ag-NPs using powder X-ray diffraction (PXRD, UV-vis spectroscopy, and transmission electron microscopy (TEM. The colloidal sols of Ag-NPs obtained at different volumes of NaOH show strong and different surface plasmon resonance (SPR peaks, which can be explained from the TEM images of Ag-NPs and their particle size distribution. Compared with other synthetic methods, this work is green, rapid, and simple to use. The newly prepared Ag-NPs may have many potential applications in chemical and biological industries.

The Product Quality Research Institute (PQRI) Leachables and Extractables Working Group Initiatives for Parenteral and Ophthalmic Drug Product (PODP).

Science.gov (United States)

Paskiet, Diane; Jenke, Dennis; Ball, Douglas; Houston, Christopher; Norwood, Daniel L; Markovic, Ingrid

2013-01-01

The Product Quality Research Institute (PQRI) is a non-profit consortium of organizations working together to generate and share timely, relevant, and impactful information that advances drug product quality and development. The collaborative activities of PQRI participants have, in the case of orally inhaled and nasal drug products (OINDPs), resulted in comprehensive and widely-accepted recommendations for leachables assessments to help ensure patient safety with respect to this class of packaged drug products. These recommendations, which include scientifically justified safety thresholds for leachables, represent a significant milestone towards establishing standardized approaches for safety qualification of leachables in OINDP. To build on the success of the OINDP effort, PQRI's Parenteral and Ophthalmic Drug Products (PODP) Leachables and Extractables Working Group was formed to extrapolate the OINDP threshold concepts and best practice recommendations to other dosage forms with high concern for interaction with packaging/delivery systems. This article considers the general aspects of leachables and their safety assessment, introduces the PODP Work Plan and initial study Protocol, discusses the laboratory studies being conducted by the PODP Chemistry Team, outlines the strategy being developed by the PODP Toxicology Team for the safety qualification of PODP leachables, and considers the issues associated with application of the safety thresholds, particularly with respect to large-volume parenterals. Lastly, the unique leachables issues associated with biologics are described. The Product Quality Research Institute (PQRI) is a non-profit consortium involving industry organizations, academia, and regulatory agencies that together provide recommendations in support of regulatory guidance to advance drug product quality. The collaborative activities of the PQRI Orally Inhaled and Nasal Drug Products Leachables and Extractables Working Group resulted in a

Drug-enhanced carbon monoxide production from heme by cytochrome P450 reductase

Directory of Open Access Journals (Sweden)

Dragic Vukomanovic

2017-01-01

Full Text Available Carbon monoxide (CO formed endogenously is considered to be cytoprotective, and the vast majority of CO formation is attributed to the degradation of heme by heme oxygenases-1 and -2 (HO-1, HO-2. Previously, we observed that brain microsomes containing HO-2 produced many-fold more CO in the presence of menadione and its congeners; herein we explored these observations further. We determined the effects of various drugs on CO production of rat brain microsomes and recombinant human cytochrome P450 reductase (CPR; CO was measured by gas chromatography with reductive detection. Brain microsomes of Sprague-Dawley rats or recombinant human cytochrome P450 reductase (CPR were incubated with NADPH and various drugs in closed vials in phosphate buffer at pH 7.4 and 37°C. After 15 minutes, the reaction was stopped by cooling in dry ice, and the headspace gas was analyzed for CO production using gas chromatography with reductive (mercuric oxide detection. We observed drug-enhanced CO production in the presence of both microsomes and recombinant CPR alone; the presence of HO was not required. A range of structurally diverse drugs were capable of amplifying this CO formation; these molecules had structures consistent with redox cycling capability. The addition of catalase to a reaction mixture, that contained activating drugs, inhibited the production of CO. Drug-enhanced CO formation can be catalyzed by CPR. The mechanism of CPR activation was not through classical drug-receptor mediation. Redox cycling may be involved in the drug-induced amplification of CO production by CPR through the production of reactive oxygen species.

Silver Nanopartilces After Zebrafish Development and Larval Behavior: Distinct Roles for Particle Size, Coating and Composition

Science.gov (United States)

Background: Silver nanoparticles (AgNPs) act as antibacterials by releasing monovalent silver (Ag+) and are increasingly used in consumer products, thus elevating exposures in human and environmental populations. In vitro models indicate that AgNPs are likely to be developmental ...

Inactive ingredient Search for Approved Drug Products

Data.gov (United States)

U.S. Department of Health & Human Services — According to 21 CFR 210.3(b)(8), an inactive ingredient is any component of a drug product other than the active ingredient. Only inactive ingredients in the final...

Silver against Pseudomonas aeruginosa biofilms

DEFF Research Database (Denmark)

Bjarnsholt, Thomas; Kirketerp-Møller, K.; Kristiansen, S.

2007-01-01

bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa......, but that the silver concentration is important. A concentration of 5-10 ig/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 ig/mL) had no effect. The bactericidal concentration of silver required to eradicate the bacterial biofilm was 10-100 times higher than that used to eradicate...... planktonic bacteria. These observations strongly indicate that the concentration of silver in currently available wound dressings is much too low for treatment of chronic biofilm wounds. It is suggested that clinicians and manufacturers of the said wound dressings consider whether they are treating wounds...

Development of surface plasmon resonance-based sensor for detection of silver nanoparticles in food and the environment

NARCIS (Netherlands)

Rebe-Raz, S.; Leontaridou, M.; Bremer, M.G.E.G.; Peters, R.J.B.; Weigel, S.

2012-01-01

Silver nanoparticles are recognized as effective antimicrobial agents and have been implemented in various consumer products including washing machines, refrigerators, clothing, medical devices, and food packaging. Alongside the silver nanoparticles benefits, their novel properties have raised

Silver resistance in Gram-negative bacteria: a dissection of endogenous and exogenous mechanisms.

Science.gov (United States)

Randall, Christopher P; Gupta, Arya; Jackson, Nicole; Busse, David; O'Neill, Alex J

2015-04-01

To gain a more detailed understanding of endogenous (mutational) and exogenous (horizontally acquired) resistance to silver in Gram-negative pathogens, with an emphasis on clarifying the genetic bases for resistance. A suite of microbiological and molecular genetic techniques was employed to select and characterize endogenous and exogenous silver resistance in several Gram-negative species. In Escherichia coli, endogenous resistance arose after 6 days of exposure to silver, a consequence of two point mutations that were both necessary and sufficient for the phenotype. These mutations, in ompR and cusS, respectively conferred loss of the OmpC/F porins and derepression of the CusCFBA efflux transporter, both phenotypic changes previously linked to reduced intracellular accumulation of silver. Exogenous resistance involved derepression of the SilCFBA efflux transporter as a consequence of mutation in silS, but was additionally contingent on expression of the periplasmic silver-sequestration protein SilE. Silver resistance could be selected at high frequency (>10(-9)) from Enterobacteriaceae lacking OmpC/F porins or harbouring the sil operon and both endogenous and exogenous resistance were associated with modest fitness costs in vitro. Both endogenous and exogenous silver resistance are dependent on the derepressed expression of closely related efflux transporters and are therefore mechanistically similar phenotypes. The ease with which silver resistance can become selected in some bacterial pathogens in vitro suggests that there would be benefit in improved surveillance for silver-resistant isolates in the clinic, along with greater control over use of silver-containing products, in order to best preserve the clinical utility of silver. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

Plasma-Induced Wafer-Scale Self-Assembly of Silver Nanoparticles and Application to Biochemical Sensing

Directory of Open Access Journals (Sweden)

Yunbo Shi

2015-06-01

Full Text Available In this work, the wafer-scale silver nanoparticles fabricated by a self-assembly method was demonstrated based on a magnetron sputtering and plasma treatment process. Silver nanoparticles of different sizes and shapes were prepared, and the effects of the plasma treatment time, plasma gas composition, and power were systematically investigated to develop a method for low-cost and large-scale fabrication of silver nanoparticles. Furthermore, the surface-enhanced Raman scattering experiments: crystal violet, as the probe, was absorbed on the silver nanoparticles film of different size and density, and get the phenomena of surface-enhanced Raman scattering and surface-enhanced fluorescence. The results show that the proposed technique provides a rapid method for the fabrication of silver nanomaterial; the method is adaptable to large-scale production and is compatible with the fabrication of other materials and biosensors.

One-Pot Silver Nanoring Synthesis

Science.gov (United States)

Drogat, Nicolas; Granet, Robert; Sol, Vincent; Krausz, Pierre

2010-03-01

Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV-vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO3/NaBH4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation.

Identification of antimycotic drugs transformation products upon UV exposure

Energy Technology Data Exchange (ETDEWEB)

Casado, Jorge; Rodríguez, Isaac, E-mail: isaac.rodriguez@usc.es; Ramil, María; Cela, Rafael

2015-05-30

Highlights: • Evaluation of antimycotic drugs UV stabilities in model supports. • Simultaneous detection of precursor drugs and transformation products. • Transformation products identification from their scan, accurate MS/MS spectra. • Directed search of identified transformation products in sand and soil samples. • Preliminary toxicity estimations. - Abstract: The reactivity of three imidazolic, environmental persistent antimycotic drugs (clotrimazole, CTZ; ketoconazole, KTZ; and miconazole, MCZ) upon exposure to ultraviolet (UV) radiation is discussed. First, precursor compounds were immobilized in a silicone support which was further exposed to UV light at two different wavelengths: 254 and 365 nm. After solvent desorption, degradation kinetics of the precursor pharmaceuticals, identification of the arising transformation products (TPs) and evaluation of their time-course were investigated by liquid chromatography (LC) with quadrupole time-of-flight (QTOF) mass spectrometry (MS) detection. The three antimycotics displayed similar stabilities when exposed to 254 nm light; however, CTZ was significantly more stable than MCZ and KTZ when irradiated with the 365 nm lamp. TPs identified in silicone supports resulted from de-chlorination, cleavage, intra-molecular cyclization and hydroxylation reactions. Many of these species were also detected when exposing other solid matrices, such as sand and agricultural soil, previously spiked with target compounds, to UV light. The 50% estimated lethal concentration, calculated using the 48-h Daphnia magna test, for the two main TPs of CTZ and MCZ, at both wavelengths, were lower than those corresponding to the precursor drugs.

Identification of antimycotic drugs transformation products upon UV exposure

International Nuclear Information System (INIS)

Casado, Jorge; Rodríguez, Isaac; Ramil, María; Cela, Rafael

2015-01-01

Highlights: • Evaluation of antimycotic drugs UV stabilities in model supports. • Simultaneous detection of precursor drugs and transformation products. • Transformation products identification from their scan, accurate MS/MS spectra. • Directed search of identified transformation products in sand and soil samples. • Preliminary toxicity estimations. - Abstract: The reactivity of three imidazolic, environmental persistent antimycotic drugs (clotrimazole, CTZ; ketoconazole, KTZ; and miconazole, MCZ) upon exposure to ultraviolet (UV) radiation is discussed. First, precursor compounds were immobilized in a silicone support which was further exposed to UV light at two different wavelengths: 254 and 365 nm. After solvent desorption, degradation kinetics of the precursor pharmaceuticals, identification of the arising transformation products (TPs) and evaluation of their time-course were investigated by liquid chromatography (LC) with quadrupole time-of-flight (QTOF) mass spectrometry (MS) detection. The three antimycotics displayed similar stabilities when exposed to 254 nm light; however, CTZ was significantly more stable than MCZ and KTZ when irradiated with the 365 nm lamp. TPs identified in silicone supports resulted from de-chlorination, cleavage, intra-molecular cyclization and hydroxylation reactions. Many of these species were also detected when exposing other solid matrices, such as sand and agricultural soil, previously spiked with target compounds, to UV light. The 50% estimated lethal concentration, calculated using the 48-h Daphnia magna test, for the two main TPs of CTZ and MCZ, at both wavelengths, were lower than those corresponding to the precursor drugs

Pulmonary and cardiovascular responses of rats to inhalation of silver nanoparticles.

Science.gov (United States)

Roberts, Jenny R; McKinney, Walter; Kan, Hong; Krajnak, Kristine; Frazer, David G; Thomas, Treye A; Waugh, Stacey; Kenyon, Allison; MacCuspie, Robert I; Hackley, Vincent A; Castranova, Vincent

2013-01-01

Exposure to wet aerosols generated during use of spray products containing silver (Ag) has not been evaluated. The goal was to assess the potential for cardiopulmonary toxicity following an acute inhalation of wet silver colloid. Rats were exposed by inhalation to a low concentration (100 μg/m(3) ) using an undiluted commercial antimicrobial product (20 mg/L total silver; approximately 33 nm mean aerodynamic diameter [MAD]) or to a higher concentration (1000 μg/m(3)) using a suspension (200 mg/L total silver; approximately 39 nm MAD) synthesized to possess a similar size distribution of Ag nanoparticles for 5 h. Estimated lung burdens from deposition models were 0, 1.4, or 14 μg Ag/rat after exposure to control aerosol, low, and high doses, respectively. At 1 and 7 d postexposure, the following parameters were monitored: pulmonary inflammation, lung cell toxicity, alveolar air/blood barrier damage, alveolar macrophage activity, blood cell differentials, responsiveness of tail artery to vasoconstrictor or vasodilatory agents, and heart rate and blood pressure in response to isoproterenol or norepinephrine, respectively. Changes in pulmonary or cardiovascular parameters were absent or nonsignificant at 1 or 7 d postexposure with the exceptions of increased blood monocytes 1 d after high-dose Ag exposure and decreased dilation of tail artery after stimulation, as well as elevated heart rate in response to isoproterenol 1 d after low-dose Ag exposure, possibly due to bioavailable ionic Ag in the commercial product. In summary, short-term inhalation of nano-Ag did not produce apparent marked acute toxicity in this animal model.

21 CFR 341.72 - Labeling of antihistamine drug products.

Science.gov (United States)

2010-04-01

..., unless directed by a doctor, if you have a breathing problem such as emphysema or chronic bronchitis, or... Section 341.72 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... product if you are taking sedatives or tranquilizers, without first consulting your doctor. Use caution...

Surface Phenomena at Silver Nanoparticles in the Context of Toxicology

DEFF Research Database (Denmark)

Miclaus, Teodora

2015-01-01

Nanoparticle research and applications are rapidly expanding areas and large scale production and use of nanomaterials has prompted concern regarding their safety for humans and the environment. Nanotoxicology aims to offer answers to issues that may arise in regards to potential harmful effects...... associated with engineered nanomaterials. Among these materials, silver nanoparticles are some of the most widely employed and thus represent a major point of focus in nanotoxicology and the topic of this PhD thesis. While nanoparticles have, upon synthesis, well-defined characteristics, specific...... of nanotoxicology. The main aim of this PhD research is to investigate these phenomena at the surface of silver nanoparticles under conditions that are relevant for in vitro studies in order to understand their implications for nano-silver toxicity. Upon contact with biological fluids, particles get coated...

Ion induced transformation of polymer films into diamond-like carbon incorporating silver nano particles

International Nuclear Information System (INIS)

Schwarz, Florian P.

2010-01-01

Silver containing diamond-like carbon (DLC) is an interesting material for medical engineering from several points of view. On the one hand DLC provides high mechanical robustness. It can be used as biocompatible and wear resistant coating for joint replacing implants. On the other hand silver has antimicrobial properties, which could reduce post-operative inflammations. However conventional production of Ag-DLC by co-deposition of silver and carbon in a plasma process is problematic since it does not allow for a separate control of nano particle morphology and matrix properties. In this work an alternative production method has been developed to circumvent this problem. In metall-DLC-production by ion implantation into a nano composite, silver nano particles are initially formed in solution and then incorporated within a polymer matrix. Finally the polymer is transformed into DLC by ion implantation. The aspects and single steps of this method were investigated with regard to the resulting material's properties. The goal was to design an economically relevant deposition method. Based on experimental results a model of the transformation process has been established, which has also been implemented in a computer simulation. Finally the antibacterial properties of the material have been checked in a biomedical test. Here a bacterial killing rate of 90% could be achieved. (orig.)

Electrochemical study of the tarnish layer of silver deposited on glass

OpenAIRE

Ben Amor , Yasser; Sutter , Eliane; Takenouti , Hisasi; Tribollet , Bernard; Boinet , M.; Faure , R.; Balencie , J.; Durieu , G.

2014-01-01

International audience; Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the tarnished thin layer of silver deposited on glass. Instead of natural tarnishing in air environment, an acceleration of tarnishing process was realized by immersion of Ag covered glass in 10 μM K2S medium. The X-ray photoelectron spectroscopy (XPS) shows that tarnishing product formed on the silver surface consisted of Ag2S and Ag2O. As electrochemical characterizatio...

A novel luminol chemiluminescent method catalyzed by silver/gold alloy nanoparticles for determination of anticancer drug flutamide.

Science.gov (United States)

Chaichi, Mohammad Javad; Azizi, Seyed Naser; Heidarpour, Maryam

2013-12-01

It was found that silver/gold alloy nanoparticles enhance the chemiluminescence (CL) of the luminol-H2O2 system in alkaline solution. The studies of UV-Vis spectra, CL spectra, effects of concentrations luminol, hydrogen peroxide and silver/gold alloy nanoparticles solutions were carried out to explore the CL enhancement mechanism. Flutamide was found to quench the CL signals of the luminol-H2O2 reaction catalyzed by silver/gold alloy nanoparticles, which made it applicable for the determination of flutamide. Under the optimum conditions, the CL intensity is proportional to the concentration of the flutamide in solution over the range 5.0 × 10(-7) to 1.0 × 10(-4)mol L(-1). Detection limit was obtained 1.2 × 10(-8)mol L(-1)and the relative standard deviation (RSD) γ5%. This work is introduced as a new method for the determination of flutamide in commercial tablets. Box-Behnken experimental design is applied to investigate and validate the CL measurement parameters. Copyright © 2013 Elsevier B.V. All rights reserved.

Detection and characterization of silver nanoparticles and dissolved species of silver in culture medium and cells by AsFlFFF-UV-Vis-ICPMS: application to nanotoxicity tests.

Science.gov (United States)

Bolea, E; Jiménez-Lamana, J; Laborda, F; Abad-Álvaro, I; Bladé, C; Arola, L; Castillo, J R

2014-03-07

A methodology based on Asymmetric Flow Field-Flow Fractionation (AsFlFFF) coupled with UV-Vis absorption spectrometry and ICP mass spectrometry (ICPMS) has been developed and applied to the study of silver nanoparticles (AgNPs) and dissolved species of silver in culture media and cells used in cytotoxicity tests. The effect of a nano-silver based product (protein stabilized silver nanoparticles ca. 15 nm average diameter) on human hepatoma (HepG2) cell viability has been studied. UV-Vis absorption spectrometry provided information about the nature (organic vs. nanoparticle) of the eluted species, whereas the silver was monitored by ICPMS. A shift towards larger hydrodynamic diameters was observed in the AgNPs after a 24 hour incubation period in the culture medium, which suggests a "protein corona" effect. Silver(I) associated with proteins present in the culture medium has also been detected, as a consequence of the oxidation process experimented by the AgNPs. However, the Ag(I) released into the culture medium did not justify the toxicity levels observed. AgNPs associated with the cultured HepG2 cells were also identified by AsFlFFF, after applying a solubilisation process based on the use of tetramethylammonium hydroxide (TMAH) and Triton X-100. These results have been confirmed by transmission electronic microscopy (TEM) analysis of the fractions collected from the AsFlFFF. The effect of AgNPs on HepG2 cells has been compared to that caused by silver(I) as AgNO3 under the same conditions. The determination of the total content of silver in the cells confirms that a much larger mass of silver as AgNPs with respect to AgNO3 (16 to 1) is needed to observe a similar toxicity.

Silver nanoparticle production by the fungus Fusarium oxysporum: nanoparticle characterisation and analysis of antifungal activity against pathogenic yeasts

Directory of Open Access Journals (Sweden)

Kelly Ishida

2014-04-01

Full Text Available The microbial synthesis of nanoparticles is a green chemistry approach that combines nanotechnology and microbial biotechnology. The aim of this study was to obtain silver nanoparticles (SNPs using aqueous extract from the filamentous fungus Fusarium oxysporum as an alternative to chemical procedures and to evaluate its antifungal activity. SNPs production increased in a concentration-dependent way up to 1 mM silver nitrate until 30 days of reaction. Monodispersed and spherical SNPs were predominantly produced. After 60 days, it was possible to observe degenerated SNPs with in additional needle morphology. The SNPs showed a high antifungal activity against Candida and Cryptococcus , with minimum inhibitory concentration values ≤ 1.68 µg/mL for both genera. Morphological alterations of Cryptococcus neoformans treated with SNPs were observed such as disruption of the cell wall and cytoplasmic membrane and lost of the cytoplasm content. This work revealed that SNPs can be easily produced by F. oxysporum aqueous extracts and may be a feasible, low-cost, environmentally friendly method for generating stable and uniformly sized SNPs. Finally, we have demonstrated that these SNPs are active against pathogenic fungi, such as Candida and Cryptococcus .

Photocatalytic decomposition of diclofenac potassium using silver-modified TiO2 thin films

International Nuclear Information System (INIS)

Cavalheiro, A.A.; Bruno, J.C.; Saeki, M.J.; Valente, J.P.S.; Florentino, A.O.

2008-01-01

The effects of silver insertion on the TiO 2 photocatalytic activity for the degradation of diclofenac potassium were reported here. Techniques such as X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy were used to comprehend the relation between structure and properties of the silver-modified TiO 2 thin films obtained by the sol-gel method. The lattice parameters and the crystallinity of TiO 2 anatase phase were affected by inserted silver, and the film thickness increased about 4 nm for each 1 wt.% of silver inserted. The degradation of diclofenac potassium and by-products reached an efficiency of 4.6 mg C W -1 when the material was modified with silver. Although the first step of degradation involves only the photochemical process related to the loss of the chlorine and hydrogen atoms. This cyclization reaction leads to the formation of intermediate, which degradation is facilitated by the modified material

Antibacterial Activity of Silver Nanoparticles Synthesized by Using Extracts of Hedera helix

Directory of Open Access Journals (Sweden)

Ahmadreza Abbasifar

2017-01-01

Full Text Available Background Silver nanoparticles (AgNPs are one of the most widely applicable particles whose application is increasing in Nano world daily. Silver nanoparticles have expressed significant advances owing to wide range of applications in the field of bio-medical, sensors, antimicrobials, catalysts, electronics, optical fibers, agricultural, bio-labeling and the other areas. Green synthesis is the safe and easiest method of producing silver nanoparticles. Because of the production of the silver ions, silver nanoparticles are found to have the antibacterial activity. Objectives The aim of this study was to investigate antibacterial activity of silver nanoparticles synthesized by using extracts of Hedera helix against Bacillus subtilis and Klebsiella pneumoniae. Methods In this experimental study AgNPs were prepared by the reaction of 1mM silver nitrate and extracts of Hedera helix. Antibacterial activity of AgNPs was assessed by using disc diffusion method against Bacillus subtilis and Klebsiella pneumoniae. The AgNPs were characterized by UV-visible (vis spectrophotometer, particle size analyzer by dynamic light scattering (DLS method, transmission electron microscopy (TEM. Results AgNPs obtained showed significantly higher antimicrobial activities against B. subtilis and K. pneumonia in comparison to both AgNO3 and raw plant extracts. Conclusions Biological methods are a good competent for the chemical procedures, which are environment friendly and convenient.

Effect of nano-silver and boric acid on extending the vase life of cut rose (Rosa hybrida L.).

Science.gov (United States)

Hashemabadi, Davood; Liavali, Mahbanoo Hoseinzadeh; Kaviani, Behzad; Mousavi, Meysam; Keyghobadi, Saghi; Zahiri, Samaneh

2014-09-01

Silver nano-particles (2-5 nm diam.), as antimicrobial agent and boric acid, as ethylene production inhibitor are used for enhancing the quality and vase life of cut flowers. In the present study the effects of a preservative solution containing nano-silver and boric acid on some traits of cut rose (Rosa hybrida L. cv. Yellow Island) including vase life, ethylene production, dry weight percentage, chlorophyll content, flower opening index, beta-carotene of petals and the number of basal stem end bacteria were investigated. The results showed that the effect of nano-silver and boric acid as either solitary or in combination with each other were significant (p rose treated with 100 mg l(-1) boric acid along with 5 mg l(-1) nano-silver. The lowest number of bacteria in the end of stem was calculated in cut flowers treated with the highest concentrations of boric acid (300 mg l(-1)) and nano-silver (20 mg l(-1)).

Production of electrospun polyvinyl alcohol/microbial synthesized silver nanoparticles scaffold for the treatment of fungating wounds

Science.gov (United States)

Yahyaei, Behrooz; Manafi, Sahebali; Fahimi, Bijan; Arabzadeh, Sepideh; Pourali, Parastoo

2018-03-01

Fungating wounds usually develop in patients with advanced cancer, which responds poorly to treatments. Such wounds can be treated using suitable dressings. For this purpose, a recent research produced a new type of wound dressing with antibacterial and anticancer properties. The culture supernatant of Fusarium oxysporum was challenged with silver nitrate and heated for 5 min. Production of silver nanoparticles (SNPs) was confirmed using spectrophotometer, transmission electron microscopy (TEM), and X-ray diffraction (XRD) analysis. A solution of 10% (w/w) poly vinyl alcohol (PVA) and different volumes of SNP solutions were provided, where each solution was separately used for electrospinning. The obtained PVA/SNPs film evaluated under morphological characterization using field emission scanning electron microscope (FE-SEM) and its antibacterial and anticancer activities were measured. Results confirmed the presence of SNPs in the reaction mixture with sizes less than 50 nm, spherical and oval in shapes. FE-SEM results confirmed that SNPs were seen inside and entrapped between PVA in the PVA/SNPs membrane, composed of 50% of each material. This film had acceptable antibacterial properties against four different bacterial strains and a good anticancer activity against the human melanoma cell line (COLO 792) in contrast to the control one. A recent research introduced a new and fast biological method for the synthesis of SNPs, having acceptable antibacterial and anticancer activities. Further studies are needed to support the obtained results.

Morphology-controlled synthesis of silver nanostructures via a seed catalysis process

Science.gov (United States)

Chen, Chang; Wang, Li; Yu, Haojie; Wang, Jianjun; Zhou, Junfeng; Tan, Qiaohua; Deng, Libo

2007-03-01

A novel, effective strategy named 'seed catalysis' has been described here to synthesize silver nanostructures with controllable morphology. Typically, we added Na2S into the reaction system and the Ag2S semiconductor colloids formed at the initial stage would act as both seeds and catalyst in the silver reduction. The morphology of products is controlled by the concentration of Na2S added to the system. Low concentration of Na2S gives nanocubes of 40-50 nm in size, while a high concentration of Na2S is of benefit to obtain nanowires. The growth of the silver crystal is also accelerated by the catalysis of Ag2S. Electron microscopy and UV-vis absorption spectra have been used to investigate the evolution of silver nanowires, and a reasonable mechanism to explain the role of Ag2S seeds has also been suggested. This semiconductor seed catalysis strategy will provide wide applications in the fabrication of metal nanomaterials.

Morphology-controlled synthesis of silver nanostructures via a seed catalysis process

International Nuclear Information System (INIS)

Chen Chang; Wang Li; Yu Haojie; Wang Jianjun; Zhou Junfeng; Tan Qiaohua; Deng Libo

2007-01-01

A novel, effective strategy named 'seed catalysis' has been described here to synthesize silver nanostructures with controllable morphology. Typically, we added Na 2 S into the reaction system and the Ag 2 S semiconductor colloids formed at the initial stage would act as both seeds and catalyst in the silver reduction. The morphology of products is controlled by the concentration of Na 2 S added to the system. Low concentration of Na 2 S gives nanocubes of 40-50 nm in size, while a high concentration of Na 2 S is of benefit to obtain nanowires. The growth of the silver crystal is also accelerated by the catalysis of Ag 2 S. Electron microscopy and UV-vis absorption spectra have been used to investigate the evolution of silver nanowires, and a reasonable mechanism to explain the role of Ag 2 S seeds has also been suggested. This semiconductor seed catalysis strategy will provide wide applications in the fabrication of metal nanomaterials

Church silver in the monetary reform of 1922-1924 years

Directory of Open Access Journals (Sweden)

Ivanov Sergei, deacon

2015-12-01

Full Text Available This article offers support the claim expense seized in 1922 under the slogan of helping the starving of church property in the minting of coins in connection with the monetary reform. It is primarily a silver, whose share in the value of the selected property in the existing temples was 86 percent. Need dragmetalah as the reform of the circulation of money there, regardless of the problem of hunger 1921–1922 and determined refusal of the Bolshevik leaders from the course on monetary economy in the post-war chaos. Evidence for the main thesis of the article served as the internal reports of structural divisions of People’s Commissariat of Finance and the People’s Commissariat of Workers ‘and Peasants’ Inspection, which indicated that in the period of the campaign for the withdrawal and delivery of church property in the state store, recently seen as the main source of silver for coinage on Petrograd Mint. Information about church silver was present in the reports to send to the metal from Gokhran Mint statements and the amount of metal intended for coinage. Demand for silver for the execution of production programs for minting exceed the available reserves of the metal, which resulted in the purchase of silver on foreign markets and buying coins Imperial coinage in the population of the country. Silver in donations and reform played a role supportive factor for strengthening confidence in the paper currency treasury.

Antitumor activity of colloidal silver on MCF-7 human breast cancer cells

Directory of Open Access Journals (Sweden)

Franco-Molina Moisés A

2010-11-01

Full Text Available Abstract Background Colloidal silver has been used as an antimicrobial and disinfectant agent. However, there is scarce information on its antitumor potential. The aim of this study was to determine if colloidal silver had cytotoxic effects on MCF-7 breast cancer cells and its mechanism of cell death. Methods MCF-7 breast cancer cells were treated with colloidal silver (ranged from 1.75 to 17.5 ng/mL for 5 h at 37°C and 5% CO2 atmosphere. Cell Viability was evaluated by trypan blue exclusion method and the mechanism of cell death through detection of mono-oligonucleosomes using an ELISA kit and TUNEL assay. The production of NO, LDH, and Gpx, SOD, CAT, and Total antioxidant activities were evaluated by colorimetric assays. Results Colloidal silver had dose-dependent cytotoxic effect in MCF-7 breast cancer cells through induction of apoptosis, shown an LD50 (3.5 ng/mL and LD100 (14 ng/mL (*P Conclusions The present results showed that colloidal silver might be a potential alternative agent for human breast cancer therapy.

One-Pot Silver Nanoring Synthesis

Directory of Open Access Journals (Sweden)

Drogat Nicolas

2009-01-01

Full Text Available Abstract Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV–vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings depended on AgNO3/NaBH4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation.

Silver diamine fluoride: a caries "silver-fluoride bullet".

Science.gov (United States)

Rosenblatt, A; Stamford, T C M; Niederman, R

2009-02-01

The antimicrobial use of silver compounds pivots on the 100-year-old application of silver nitrate, silver foil, and silver sutures for the prevention and treatment of ocular, surgical, and dental infections. Ag(+) kills pathogenic organisms at concentrations of linings, water purification systems, hospital gowns, and caries prevention. To distill the current best evidence relative to caries, this systematic review asked: Will silver diamine fluoride (SDF) more effectively prevent caries than fluoride varnish? A five-database search, reference review, and hand search identified 99 human clinical trials in three languages published between 1966 and 2006. Dual review for controlled clinical trials with the patient as the unit of observation, and excluding cross-sectional, animal, in vitro studies, and opinions, identified 2 studies meeting the inclusion criteria. The trials indicated that SDF's lowest prevented fractions for caries arrest and caries prevention were 96.1% and 70.3%, respectively. In contrast, fluoride varnish's highest prevented fractions for caries arrest and caries prevention were 21.3% and 55.7%, respectively. Similarly, SDF's highest numbers needed to treat for caries arrest and caries prevention were 0.8 (95% CI=0.5-1.0) and 0.9 (95% CI=0.4-1.1), respectively. For fluoride varnish, the lowest numbers needed to treat for caries arrest and prevention were 3.7 (95% CI=3.4-3.9) and 1.1 (95% CI=0.7-1.4), respectively. Adverse events were monitored, with no significant differences between control and experimental groups. These promising results suggest that SDF is more effective than fluoride varnish, and may be a valuable caries-preventive intervention. As well, the availability of a safe, effective, efficient, and equitable caries-preventive agent appears to meet the criteria of both the WHO Millennium Goals and the US Institute of Medicine's criteria for 21st century medical care.

Investigation of interaction between silver oxide electrode and separator hydrated cellulose film in silver-cadmium accumulators

International Nuclear Information System (INIS)

Molotkova, E.N.; Yarochkina, E.N.

1975-01-01

Oxidation-reduction interaction of the oxysilver electrode with hydrocellulose film during storing charged silver-cadmium accumulators. It was demonstrated that accumulator electric characteristics durinq storing are linearly depending on the capacity of this hydrocellulose film to interact with silver oxide: the more silver is absorbed by film the quicker is the decreasing of the electromotive force and capacity of the accumulators. Preservation of the silver electrode capacity in the silver-cadmium accumulators is determined first of all by hydrocellulose separation film properties and especially by film layer adjacent to positive electrode. The more inert film layer is, regarding to silver oxide in the electrolite, the slower is dissolution of the electrode and also decompousing speed of AgO, the longer is the accumulator preservation time

Green Biosynthesis of Silver Nanoparticles Using Callicarpa maingayi Stem Bark Extraction

Directory of Open Access Journals (Sweden)

Mohammed Zidan

2012-07-01

Full Text Available Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs due to their multiple applications. The use of plants in the green synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the green biosynthesis of silver nanoparticles using Callicarpa maingayi stem bark extract has been reported. Characterizations of nanoparticles were done using different methods, which include; ultraviolet-visible spectroscopy (UV-Vis, powder X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray fluorescence (EDXF spectrometry, zeta potential measurements and Fourier transform infrared (FT-IR spectroscopy. UV-visible spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at around 456 nm. The TEM study showed that mean diameter and standard deviation for the formation of silver nanoparticles were 12.40 ± 3.27 nm. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc structure. The most needed outcome of this work will be the development of value added products from Callicarpa maingayi for biomedical and nanotechnology based industries.

Evaluation of bactericidal efficacy of silver ions on Escherichia coli for drinking water disinfection.

Science.gov (United States)

Pathak, Satya P; Gopal, K

2012-07-01

The purpose of this study is the development of a suitable process for the disinfection of drinking water by evaluating bactericidal efficacy of silver ions from silver electrodes. A prototype of a silver ioniser with silver electrodes and control unit has been fabricated. Silver ions from silver electrodes in water samples were estimated with an atomic absorption spectrophotometer. A fresh culture of Escherichia coli (1.75 × 10(3) c.f.u./ml) was exposed to 1, 2, 5, 10 and 20 ppb of silver ions in 100 ml of autoclaved tap water for 60 min. The effect of different pH and temperatures on bactericidal efficacy was observed at constant silver ion concentration (5 ppb) and contact time of 30 min. The maximum bactericidal activity (100%) was observed at 20 ppb of silver ion concentration indicating total disinfection after 20 min while minimum bactericidal activity (25%) was observed after 10 min at 01 ppb of silver ions. Likewise, 100% bactericidal activity was noticed with 2, 5 and 10 ppb of silver ions after 60, 50 and 40 min, respectively. Bactericidal activity at pH 5, 6, 7, 8 and 9 was observed at 79.9%, 79.8%, 80.5%, 100% and 100%, respectively, whereas it was 80.4%, 88.3%, 100%, 100% and 100% at 10°C, 20°C, 30°C, 40°C and 50°C, respectively. The findings of this study revealed that very low concentrations of silver ions at pH 8-9 and temperature >20°C have bactericidal efficacy for total disinfection of drinking water. Silver ionisation is suitable for water disinfection and an appropriate alternative to chlorination which forms carcinogenic disinfection by-products.

Low-silver radiographic detectors

International Nuclear Information System (INIS)

Troitskii, V.A.; Novikov, I.A.; Nikitin, V.F.; Krasnyi-Admoni, L.V.; Valevich, M.I.; Belyi, N.G.; Grom, V.S.

1988-01-01

X-ray films and screens with low silver content for use in weld radiography are reviewed and tested. Properties examined include image graininess, brightness, and sensitivity to x radiation. Results are given for radiography of steel 08Kh18N10T, St20, AMG-6, copper, and titanium welds. Processing techniques for low-silver films are discussed. It is established that films and screens containing little silver can replace many x-ray films containing much more silver. Monitoring methods were developed for the new materials to cover items in classes 3-7 on GOST 23075-78 when used with equipment of RUP-150/300-10 type or classes 4-7 with pulsed x-ray equipment

The Speciation Of Silver Nanoparticles In Antimicrobial Fabric Before and After Exposure To A Hypochlorite/Detergent Solution

Science.gov (United States)

Because of their antibacterial properties, silver nanoparticles are often used in consumer products. To assess environmental and/or human health risks from these nanoparticles, there is a need to identify the chemical transformations that Silver nanoparticles undergo in differen...

One-pot silver nanoring synthesis.

OpenAIRE

Drogat , Nicolas; Granet , Robert; Sol , Vincent; Krausz , Pierre

2009-01-01

Abstract Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV–vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO3/NaBH4 ratio, pH...

Sponge-like silver obtained by decomposition of silver nitrate hexamethylenetetramine complex

Energy Technology Data Exchange (ETDEWEB)

Afanasiev, Pavel, E-mail: pavel.afanasiev@ircelyon.univ-lyon.fr

2016-07-15

Silver nitrate hexamethylenetetramine [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] coordination compound has been prepared via aqueous route and characterized by chemical analysis, XRD and electron microscopy. Decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] under hydrogen and under inert has been studied by thermal analysis and mass spectrometry. Thermal decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] proceeds in the range 200–250 °C as a self-propagating rapid redox process accompanied with the release of multiple gases. The decomposition leads to formation of sponge-like silver having hierarchical open pore system with pore size spanning from 10 µm to 10 nm. The as-obtained silver sponges exhibited favorable activity toward H{sub 2}O{sub 2} electrochemical reduction, making them potentially interesting as non-enzyme hydrogen peroxide sensors. - Graphical abstract: Thermal decomposition of silver nitrate hexamethylenetetramine coordination compound [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] leads to sponge like silver that possesses open porous structure and demonstrates interesting properties as an electrochemical hydrogen peroxide sensor. Display Omitted - Highlights: • [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] orthorhombic phase prepared and characterized. • Decomposition of [Ag(NO{sub 3})·N{sub 4}(CH{sub 2}){sub 6}] leads to metallic silver sponge with opened porosity. • Ag sponge showed promising properties as a material for hydrogen peroxide sensors.

Silver-Palladium Surfaces Inhibit Biofilm Formation

DEFF Research Database (Denmark)

Chiang, Wen-Chi; Schroll, Casper; Hilbert, Lisbeth Rischel

2009-01-01

Undesired biofilm formation is a major concern in many areas. In the present study, we investigated biofilm-inhibiting properties of a silver-palladium surface that kills bacteria by generating microelectric fields and electrochemical redox processes. For evaluation of the biofilm inhibition...... efficacy and study of the biofilm inhibition mechanism, the silver-sensitive Escherichia coli J53 and the silver-resistant E. coli J53[pMG101] strains were used as model organisms, and batch and flow chamber setups were used as model systems. In the case of the silver-sensitive strain, the silver......-palladium surfaces killed the bacteria and prevented biofilm formation under conditions of low or high bacterial load. In the case of the silver-resistant strain, the silver-palladium surfaces killed surface-associated bacteria and prevented biofilm formation under conditions of low bacterial load, whereas under...

Nonactivated titanium-dioxide nanoparticles promote the growth of Chlamydia trachomatis and decrease the antimicrobial activity of silver nanoparticles.

Science.gov (United States)

Bogdanov, A; Janovák, L; Lantos, I; Endrész, V; Sebők, D; Szabó, T; Dékány, I; Deák, J; Rázga, Z; Burián, K; Virok, D P

2017-11-01

Chlamydia trachomatis and herpes simplex virus (HSV) are the most prevalent bacterial and viral sexually transmitted infections. Due to the chronic nature of their infections, they are able to interact with titanium-dioxide (TiO 2 ) nanoparticles (NPs) applied as food additives or drug delivery vehicles. The aim of this study was to describe the interactions of these two prevalent pathogens with the TiO 2 NPs. Chlamydia trachomatis and HSV-2 were treated with nonactivated TiO 2 NPs, silver NPs and silver decorated TiO 2 NPs before infection of HeLa and Vero cells. Their intracellular growth was monitored by quantitative PCR. Unexpectedly, the TiO 2 NPs (100 μg ml -1 ) increased the growth of C. trachomatis by approximately fourfold, while the HSV-2 replication was not affected. Addition of TiO 2 to silver NPs decreased their antimicrobial activity against C. trachomatis up to 27·92-fold. In summary, nonactivated TiO 2 NPs could increase the replication of C. trachomatis and decrease the antimicrobial activity of silver NPs. The food industry or drug delivery use of TiO 2 NPs could enhance the growth of certain intracellular pathogens and potentially worsen disease symptoms, a feature that should be further investigated. © 2017 The Society for Applied Microbiology.

High-performance electrically conductive silver paste prepared by silver-containing precursor

Energy Technology Data Exchange (ETDEWEB)

Liu, Jianguo; Cao, Yu; Li, Xiangyou; Wang, Xiaoye; Zeng, Xiaoyan [Huazhong University of Science and Technology, Wuhan National Laboratory for Optoelectronics, College of Optoelectronics Science and Engineering, Wuhan (China)

2010-09-15

A high-performance electrically conductive silver paste with no solid particles before drying and/or sintering is developed, in which silver-containing precursor is employed as conductive functional phase. Thermogravimetry analysis, volume electrical resistivity tests and sintering experiments show that the paste with about 14 wt.% silver pristine content is able to achieve the volume electrical resistivity of (2-3) x 10{sup -5} {omega} cm after it is sintered at 220 C. A micro-pen direct-writing process indicates that it is very suitable for the fabrication of high-resolution (25 {mu}m) and high-integration devices and apparatus. (orig.)

The silver lining: towards the responsible and limited usage of silver.

Science.gov (United States)

Naik, K; Kowshik, M

2017-11-01

Silver has attracted a lot of attention as a powerful, broad spectrum and natural antimicrobial agent since the ancient times because of its nontoxic nature to the human body at low concentrations. It has been used in treatment of various infections and ulcers, storage of water and prevention of bacterial growth on the surfaces and within materials. However, there are numerous medical and health benefits of colloidal or nanosilver apart from its microbicidal ability which as yet has not been fully embraced by the medical community. These include antiplatelet activity, antioxidant effect, anticancer activity, wound healing and bone regeneration, enhancement of immunity, and increase in antibiotic efficiency. Additionally silver also provides protection against alcohol toxicity, upper respiratory tract infections and stomach ailments. Although nanosilver has been proposed for various topical applications, its usage by ingestion and inhalation remains controversial due to the lack of detailed and precise toxicity information. These beneficial properties of silver can be utilized by using silver at very low concentrations which are not harmful to the human body and environment. The following review discusses the diverse medical applications of silver and further recommends human clinical studies for its in vivo usage. #x00A9; 2017 The Society for Applied Microbiology.

Silver surface enrichment controlled by simultaneous RBS for reliable PIXE analysis of ancient coins

International Nuclear Information System (INIS)

Beck, L.; Alloin, E.; Berthier, C.; Reveillon, S.; Costa, V.

2008-01-01

Evidence of silver surface enrichment of ancient silver-copper coins has been pointed out in the past years. Surface enrichment can be fortuitous or intentional. In this paper, we have investigated the cleaning procedures usually performed after excavation or in museums. We have shown that chemicals or commercial products routinely used dissolve preferentially the copper phase and consequently contribute to the silver surface enrichment. As a result, surface analyses such as PIXE or XRF can be strongly affected by this effect. By using simultaneously RBS and PIXE, it is possible to check through the silver surface enrichment and then select the reliable measurements, characteristic of the bulk composition. Results on coins recently discovered and mechanically or chemically cleaned are presented

Silver nanoparticle ink technology: state of the art

Directory of Open Access Journals (Sweden)

Rajan K

2016-01-01

Full Text Available Krishna Rajan, Ignazio Roppolo, Annalisa Chiappone, Sergio Bocchini, Denis Perrone, Alessandro Chiolerio Center for Space Human Robotics, Italian Institute of Technology, Turin, Italy Abstract: Printed electronics will bring to the consumer level great breakthroughs and unique products in the near future, shifting the usual paradigm of electronic devices and circuit boards from hard boxes and rigid sheets into flexible thin layers and bringing disposable electronics, smart tags, and so on. The most promising tool to achieve the target depends upon the availability of nanotechnology-based functional inks. A certain delay in the innovation-transfer process to the market is now being observed. Nevertheless, the most widely diffused product, settled technology, and the highest sales volumes are related to the silver nanoparticle-based ink market, representing the best example of commercial nanotechnology today. This is a compact review on synthesis routes, main properties, and practical applications. Keywords: silver nanoparticles, surface plasmon resonance, nanocomposites, inks, printed electronics

Tuberculosis drug issues: prices, fixed-dose combination products and second-line drugs.

Science.gov (United States)

Laing, R O; McGoldrick, K M

2000-12-01

Access to tuberculosis drugs depends on multiple factors. Selection of a standard list of TB drugs to procure is the first step. This paper reviews the advantages and disadvantages of procuring and using fixed-dose combination (FDC) products for both the intensive and continuation phases of treatment. The major advantages are to prevent the emergence of resistance, to simplify logistic management and to reduce costs. The major disadvantage is the need for the manufacturers to assure the quality of these FDCs by bioavailability testing. The paper reports on the inclusion of second-line TB drugs in the 1999 WHO Essential Drug List (EDL). The need to ensure that these drugs are used within established DOTS-Plus programs is stressed. The price of TB drugs is determined by many factors, including producer prices, local taxes and duties as well as mark-ups and fees. TB drug prices for both the public and private sectors from industrialized and developing countries are reported. Price trends over time are also reported. The key findings of this study are that TB drug prices have generally declined in developing countries while they have increased in developed countries, both for the public and private sectors. Prices vary between countries, with the US paying as much as 95 times the price paid in a specific developing country. The prices of public sector first-line TB drugs vary little between countries, although differences do exist due to the procurement methods used. The price of tuberculin, a diagnostic agent, has increased dramatically in the US, with substantial inter-country variations in price. The paper suggests that further research is necessary to identify the reasons for the price disparities and changes over time, and suggests methods which can be used by National Tuberculosis Programme managers to ensure availability of quality assured TB drugs at low prices.

Visualisation of morphological interactionof diamond and silver nanoparticles with Salmonella enteritidis and Listeria Monocytogenes

DEFF Research Database (Denmark)

Sawosz, Ewa; Chwalibog, André; Mitura, Katarzyna

2011-01-01

Currently, medicine intensively searches for methods to transport drugs to a target (sick) point within the body. The objective of the present investigation was to evaluate morphological characteristics of the assembles of silver or diamond nanoparticles with Salmonella Enteritidis (G-) or Listeria...... monocytogenes (G+), to reveal possibilities of constructing nanoparticle-bacteria vehicles. Diamond nanoparticles (nano-D) were produced by the detonation method. Hydrocolloids of silver nanoparticles (nano-Ag) were produced by electric non-explosive patented method. Hydrocolloids of nanoparticles (200 microl...

Evaluation of optimal silver amount for the removal of methyl iodide on silver-impregnated adsorbents

International Nuclear Information System (INIS)

Park, G.I.; Cho, I.H.; Kim, J.H.; Oh, W.Z.

2001-01-01

The adsorption characteristics of methyl iodide generated from the simulated off-gas stream on various adsorbents such as silver-impregnated zeolite (AgX), zeocarbon and activated carbon were investigated. An extensive evaluation was made on the optimal silver impregnation amount for the removal of methyl iodide at temperatures up to 300 deg. C. The degree of adsorption efficiency of methyl iodide on silver-impregnated adsorbent is strongly dependent on impregnation amount and process temperature. A quantitative comparison of adsorption efficiencies on three adsorbents in a fixed bed was investigated. The influence of temperature, methyl iodide concentration and silver impregnation amount on the adsorption efficiency is closely related to the pore characteristics of adsorbents. It shows that the effective impregnation ratio was about 10wt%, based on the degree of silver utilization for the removal of methyl iodide. The practical applicability of silver-impregnated zeolite for the removal of radioiodine generated from the DUPIC process was consequently proposed. (author)

Bulk diffusion and solubility of silver and nickel in lead, lead-silver and lead-nickel solid solutions

International Nuclear Information System (INIS)

Amenzou-Badrour, H.; Moya, G.; Bernardini, J.

1988-01-01

The results of a study of solubility and bulk diffusion of /sup 110/Ag and /sup 63/Ni in lead, lead-silver and lead-nickel solid solutions in the temperature range 220 to 88 0 C are reported. Owing to the low solubility of silver and nickel in lead, Fick's solution corresponding to the boundary condition of a constant concentration of solute at the surface has been used. Depth profile concentration analysis suggests a fundamental difference between the diffusion mechanisms of silver and nickel. Since silver penetration profiles in pure lead give diffusion coefficients independent of the penetration depth and silver concentration, it is suggested that slight decreases of silver diffusivity in lead-silver solid solutions have no significance. This implies that the interstitial silver atoms do not associate significantly with each other to form Ag-Ag dimers. In contrast, different behaviors of /sup 63/Ni depth profile concentration in pure lead and saturated PbNi solid solutions agree with a Ni-Ni interaction leading to the formation of less mobile dimers near the surface in pure lead

Equivalence of complex drug products: advances in and challenges for current regulatory frameworks.

Science.gov (United States)

Hussaarts, Leonie; Mühlebach, Stefan; Shah, Vinod P; McNeil, Scott; Borchard, Gerrit; Flühmann, Beat; Weinstein, Vera; Neervannan, Sesha; Griffiths, Elwyn; Jiang, Wenlei; Wolff-Holz, Elena; Crommelin, Daan J A; de Vlieger, Jon S B

2017-11-01

Biotechnology and nanotechnology provide a growing number of innovator-driven complex drug products and their copy versions. Biologics exemplify one category of complex drugs, but there are also nonbiological complex drug products, including many nanomedicines, such as iron-carbohydrate complexes, drug-carrying liposomes or emulsions, and glatiramoids. In this white paper, which stems from a 1-day conference at the New York Academy of Sciences, we discuss regulatory frameworks in use worldwide (e.g., the U.S. Food and Drug Administration, the European Medicines Agency, the World Health Organization) to approve these complex drug products and their follow-on versions. One of the key questions remains how to assess equivalence of these complex products. We identify a number of points for which consensus was found among the stakeholders who were present: scientists from innovator and generic/follow-on companies, academia, and regulatory bodies from different parts of the world. A number of topics requiring follow-up were identified: (1) assessment of critical attributes to establish equivalence for follow-on versions, (2) the need to publish scientific findings in the public domain to further progress in the field, (3) the necessity to develop worldwide consensus regarding nomenclature and labeling of these complex products, and (4) regulatory actions when substandard complex drug products are identified. © 2017 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals, Inc. on behalf of New York Academy of Sciences.

Silver surface enrichment of silver-copper alloys: a limitation for the analysis of ancient silver coins by surface techniques

International Nuclear Information System (INIS)

Beck, L.; Bosonnet, S.; Reveillon, S.; Eliot, D.; Pilon, F.

2004-01-01

The surface enrichment of archaeological silver-copper alloys has been recognized for many years. However, the origin of this enrichment is not well defined and many hypotheses have been put forward to account for this behaviour: segregation of the components during casting, deliberate thermal and/or chemical post-treatment, abrasion or corrosion. Among the hypotheses mentioned above, we have focused our study on the first step of coin manufacturing. Replications of silver-copper standards of various compositions ranging from 30% to 80% Ag, reflecting the composition of silver blanks, have been produced. Metallographic examination, PIXE and SEM-EDS have been used for the characterization of each sample. A model of the direct enrichment has been established. This model allows us to propose a relationship between the surface composition and the silver content of the core. Comparison with data of Roman coins from the Roman site of Cha-hat teaubleau (France) and from the literature and consequences for the analyses of ancient coins by surface methods are presented

Mineral resource of the month: silver

Science.gov (United States)

Brooks, William E.

2007-01-01

Silver has been used for thousands of years as ornaments and utensils, for trade and as the basis of many monetary systems. The metal has played an important part in world history. Silver from the mines at Laurion, Greece, for example, financed the Greek victory over the Persians in 480 B.C. Silver from Potosi, Bolivia, helped Spain become a world power in the 16th and 17th centuries. And silver from the gold-silver ores at the Comstock Lode in Virginia City, Nev., helped keep the Union solvent during the Civil War.

Combinative Particle Size Reduction Technologies for the Production of Drug Nanocrystals

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Jaime Salazar

2014-01-01

Full Text Available Nanosizing is a suitable method to enhance the dissolution rate and therefore the bioavailability of poorly soluble drugs. The success of the particle size reduction processes depends on critical factors such as the employed technology, equipment, and drug physicochemical properties. High pressure homogenization and wet bead milling are standard comminution techniques that have been already employed to successfully formulate poorly soluble drugs and bring them to market. However, these techniques have limitations in their particle size reduction performance, such as long production times and the necessity of employing a micronized drug as the starting material. This review article discusses the development of combinative methods, such as the NANOEDGE, H 96, H 69, H 42, and CT technologies. These processes were developed to improve the particle size reduction effectiveness of the standard techniques. These novel technologies can combine bottom-up and/or top-down techniques in a two-step process. The combinative processes lead in general to improved particle size reduction effectiveness. Faster production of drug nanocrystals and smaller final mean particle sizes are among the main advantages. The combinative particle size reduction technologies are very useful formulation tools, and they will continue acquiring importance for the production of drug nanocrystals.

The effect of silver (Ag) addition to mechanical and electrical properties of copper alloy (Cu) casting product

Science.gov (United States)

Felicia, Dian M.; Rochiem, R.; Laia, Standley M.

2018-04-01

Copper have good mechanical properties and good electrical conductivities. Therefore, copper usually used as electrical components. Silver have better electrical conductivities than copper. Female contact resistor is one of the electrical component used in circuit breaker. This study aims to analyze the effect of silver addition to hardness, strength, and electric conductivity properties of copper alloy. This study uses variation of 0; 0.035; 0.07; 0.1 wt. % Ag (silver) addition to determine the effect on mechanical properties and electrical properties of copper alloy through sand casting process. Modelling of thermal analysis and structural analysis was calculated to find the best design for the sand casting experiments. The result of Cu-Ag alloy as cast will be characterized by OES test, metallography test, Brinell hardness test, tensile test, and LCR meter test. The result of this study showed that the addition of silver increase mechanical properties of Cu-Ag. The maximum hardness value of this alloy is 83.1 HRB which is Cu-0.01 Ag and the lowest is 52.26 HRB which is pure Cu. The maximum strength value is 153.2 MPa which is Cu-0.07 Ag and the lowest is 94.6 MPa which is pure Cu. Silver addition decrease electrical properties of this alloy. The highest electric conductivity is 438.98 S/m which is pure Cu and the lowest is 52.61 S.m which is Cu-0.1 Ag.

Screen Printing of Highly Loaded Silver Inks on Plastic Substrates Using Silicon Stencils.

Science.gov (United States)

Hyun, Woo Jin; Lim, Sooman; Ahn, Bok Yeop; Lewis, Jennifer A; Frisbie, C Daniel; Francis, Lorraine F

2015-06-17

Screen printing is a potential technique for mass-production of printed electronics; however, improvement in printing resolution is needed for high integration and performance. In this study, screen printing of highly loaded silver ink (77 wt %) on polyimide films is studied using fine-scale silicon stencils with openings ranging from 5 to 50 μm wide. This approach enables printing of high-resolution silver lines with widths as small as 22 μm. The printed silver lines on polyimide exhibit good electrical properties with a resistivity of 5.5×10(-6) Ω cm and excellent bending tolerance for bending radii greater than 5 mm (tensile strains less than 0.75%).

Silver nanoparticles: mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects

Science.gov (United States)

Prabhu, Sukumaran; Poulose, Eldho K.

2012-10-01

Silver nanoparticles are nanoparticles of silver which are in the range of 1 and 100 nm in size. Silver nanoparticles have unique properties which help in molecular diagnostics, in therapies, as well as in devices that are used in several medical procedures. The major methods used for silver nanoparticle synthesis are the physical and chemical methods. The problem with the chemical and physical methods is that the synthesis is expensive and can also have toxic substances absorbed onto them. To overcome this, the biological method provides a feasible alternative. The major biological systems involved in this are bacteria, fungi, and plant extracts. The major applications of silver nanoparticles in the medical field include diagnostic applications and therapeutic applications. In most of the therapeutic applications, it is the antimicrobial property that is being majorly explored, though the anti-inflammatory property has its fair share of applications. Though silver nanoparticles are rampantly used in many medical procedures and devices as well as in various biological fields, they have their drawbacks due to nanotoxicity. This review provides a comprehensive view on the mechanism of action, production, applications in the medical field, and the health and environmental concerns that are allegedly caused due to these nanoparticles. The focus is on effective and efficient synthesis of silver nanoparticles while exploring their various prospective applications besides trying to understand the current scenario in the debates on the toxicity concerns these nanoparticles pose.

α-Cyclodextrins Polyrotaxane Loading Silver Sulfadiazine

Directory of Open Access Journals (Sweden)

Sa Liu

2018-02-01

Full Text Available As a drug carrier, polyrotaxane (PR has been used for targeted delivery and sustained release of drugs, whereas silver sulfadiazine (SD-Ag is an emerging antibiotic agent. PR was synthesized by the use of α-cyclodextrin (CD and poly(ethylene glycol (PEG, and a specific antibacterial material (PR-(SD-Ag was then prepared by loading SD-Ag onto PR with different mass ratios. The loading capacity and the encapsulation efficiency were 90% at a mass ratio of 1:1 of PR and SD-Ag. SD-Ag was released stably and slowly within 6 d in vitro, and its cumulative release reached more than 85%. The mechanism of PR loading SD-Ag might be that SD-Ag attached to the edge of α-CD through hydrogen bonding. PR-(SD-Ag showed a higher light stability than SD-Ag and held excellent antibacterial properties against Escherichia coli (E. coli and Staphylococcus aureus (S. aureus.

pH-sensitive nanocarrier based on gold/silver core-shell nanoparticles decorated multi-walled carbon manotubes for tracing drug release in living cells.

Science.gov (United States)

Chen, Peng; Wang, Zhuyuan; Zong, Shenfei; Zhu, Dan; Chen, Hui; Zhang, Yizhi; Wu, Lei; Cui, Yiping

2016-01-15

We fabricate a multifunctional nanocarrier based on multi-walled carbon nanotubes (MWCNTs) decorated with gold/silver core-shell nanoparticles (Au@Ag NPs) and fluorescein isothiocyanate (FITC) for tracking the intracellular drug release process. In the demonstrated nanocarrier, the Au@Ag NPs adsorbed on the surface of MWCNTs were labeled with the pH-dependent SERS reporter 4-Mercaptobenzoic acid (4MBA) for SERS based pH sensing. FITC was conjugated on MWCNTs to provide fluorescence signal for tracing the MWCNTs. Fluorescent doxorubicin (DOX) was used as the model drug which can be loaded onto MWCNTs via π-π stacking and released from the MWCNTs under acidic condition. By detecting the SERS spectrum of 4MBA, the pH value around the nanocarrier could be monitored. Besides, by tracing the fluorescence of FITC and DOX, we can also investigate the drug release process in cells. Experimental results show that the proposed nanocarrier retained a well pH-sensitive performance in living cells, and the DOX detached from MWCNTs inside the lysosomes and entered into the cytoplasm with the MWCNTs being left in lysosomes. To further investigate the drug release dynamics, 2-D color-gradient pH mapping were plotted, which were calculated from the SERS spectra of 4MBA. The detailed release process and carrier distribution have been recorded as environmental pH changes during cell endocytosis. Furthermore, we also confirmed that the proposed nanocarrier has a good biocompatibility. It indicates that the designed nanocarrier have a great potential in intraceable drug delivery, cancer cells imaging and pH monitoring. Copyright © 2015 Elsevier B.V. All rights reserved.

Photocatalytic decomposition of diclofenac potassium using silver-modified TiO{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Cavalheiro, A.A. [Depto de Quimica - Instituto de Biociencias - UNESP, Distrito de Rubiao Junior, s/n, Zip Code 18.618-000, P.O. Box 510, Botucatu, SP (Brazil)], E-mail: albecava@bol.com.br; Bruno, J.C.; Saeki, M.J.; Valente, J.P.S.; Florentino, A.O. [Depto de Quimica - Instituto de Biociencias - UNESP, Distrito de Rubiao Junior, s/n, Zip Code 18.618-000, P.O. Box 510, Botucatu, SP (Brazil)

2008-07-31

The effects of silver insertion on the TiO{sub 2} photocatalytic activity for the degradation of diclofenac potassium were reported here. Techniques such as X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy were used to comprehend the relation between structure and properties of the silver-modified TiO{sub 2} thin films obtained by the sol-gel method. The lattice parameters and the crystallinity of TiO{sub 2} anatase phase were affected by inserted silver, and the film thickness increased about 4 nm for each 1 wt.% of silver inserted. The degradation of diclofenac potassium and by-products reached an efficiency of 4.6 mg{sub C} W{sup -1} when the material was modified with silver. Although the first step of degradation involves only the photochemical process related to the loss of the chlorine and hydrogen atoms. This cyclization reaction leads to the formation of intermediate, which degradation is facilitated by the modified material.

21 CFR 216.24 - Drug products withdrawn or removed from the market for reasons of safety or effectiveness.

Science.gov (United States)

2010-04-01

.... Bromfenac sodium: All drug products containing bromfenac sodium. Butamben: All parenteral drug products...). Dexfenfluramine hydrochloride: All drug products containing dexfenfluramine hydrochloride. Diamthazole... dihydrostreptomycin sulfate. Dipyrone: All drug products containing dipyrone. Encainide hydrochloride: All drug...

雷达T/R组件壳体镀银自动生产线设计%Study on Automatic Silver-Plating Production Line for Radar T/R Module Shells

Institute of Scientific and Technical Information of China (English)

宋夏; 胡江华; 叶敏; 何川金

2011-01-01

Design an automatic silver-plating production line to stabilize processing parameter, increase productivity effect,insure product quality and upgrade working condition, based on the silver-plating problem of active phased array radar T/R module shells. Then, the general planning, structural design, control system and programming of this automatic production line were specified, and at last, the deficiency and improvement of the line was proposed.%针对有源相控阵雷达T/R组件壳体的镀银要求,设计直线挂镀式镀银自动生产线来稳定工艺参数,提高生产效率,保证产品质量和改善劳动条件,并对自动生产线的总体方案、结构设计、控制系统以及程序设计进行了详细介绍,最后对生产线的不足和改进方案进行了说明.

In Vivo Toxicity of Silver Nanoparticles and Silver Ions in Zebrafish (Danio rerio

Directory of Open Access Journals (Sweden)

Katrine Bilberg

2012-01-01

Full Text Available The influence of water chemistry on characterised polyvinyl pyrrolidone- (PVP- coated silver nanoparticles (81 nm was investigated. NaCl solution series of 100–800 mg L−1 lead to initial and temporal increase in nanoparticles size, but agglomeration was limited. pH variation (5–8 had only minor influence on the hydrodynamic particle size. Acute toxicity of nanosivler to zebrafish (Danio rerio was investigated in a 48-hour static renewal study and compared with the toxicity of silver ions (AgNO3. The nanosilver and silver ion 48-hour median lethal concentration (LC50 values were 84 μg L−1 and 25 μg L−1, respectively. To investigate exposure-related stress, the fish behaviour was observed visually after 0, 3, 6, 12, 24, 27, 30, and 48 hours of both nanosilver and ionic silver treatments. These observations revealed increased rate of operculum movement and surface respiration after nanosilver exposure, suggesting respiratory toxicity. The present study demonstrates that silver nanoparticles are lethal to zebrafish.

Silver-Assisted Synthesis of Gold Nanorods: the Relation between Silver Additive and Iodide Impurities.

Science.gov (United States)

Jessl, Sarah; Tebbe, Moritz; Guerrini, Luca; Fery, Andreas; Alvarez-Puebla, Ramon A; Pazos-Perez, Nicolas

2018-04-17

Seed-mediated methods employing cetyltrimethylammonium bromide (CTAB) as a surfactant, and silver salts as additives, are the most common synthetic strategies for high-yield productions of quality Au nanorods. However, the mechanism of these reactions is not yet fully understood and, importantly, significant lab-to-lab reproducibility issues still affect these protocols. In this study, the direct correlation between the hidden content of iodide impurities in CTAB reagents, which can drastically differ from different suppliers or batches, and the optimal concentration of silver required to maximize the nanorods yield is demonstrated. As a result, high-quality nanorods are obtained at different iodide contents. These results are interpreted based on the different concentrations of CTAB and cetyltrimethylammonium iodide (CTAI) complexes with Ag + and Au + metal ions in the growth solution, and their different binding affinity and reduction potential on distinct crystallographic planes. Notably, the exhaustive conversion of CTAI-Au + to CTAI-Ag + appears to be the key condition for maximizing the nanorod yield. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In situ reduction of antibacterial silver ions to metallic silver nanoparticles on bioactive glasses functionalized with polyphenols

Energy Technology Data Exchange (ETDEWEB)

Ferraris, S., E-mail: sara.ferraris@polito.it [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy); Miola, M. [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy); Department of Health Sciences, Università del Piemonte Orientale UPO, Via Solaroli 17, 28100, Novara (Italy); Cochis, A.; Azzimonti, B.; Rimondini, L. [Department of Health Sciences, Università del Piemonte Orientale UPO, Via Solaroli 17, 28100, Novara (Italy); Prenesti, E. [Department of Chemistry, Università degli Studi di Torino, Via Pietro Giuria 7, Torino, 10125 (Italy); Vernè, E. [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy)

2017-02-28

Highlights: • Gallic acid and natural polyphenols were grafted onto bioactive glasses. • Grafting ability was dependent on glass reactivity. • In situ reduction of silver nanoparticles was performed onto functionalized glasses. • Bioactive glasses decorated with silver nanoparticles showed antibacterial activity. - Abstract: The realization of surfaces with antibacterial properties due to silver nanoparticles loaded through a green approach is a promising research challenge of the biomaterial field. In this research work, two bioactive glasses have been doubly surface functionalized with polyphenols (gallic acid or natural polyphenols extracted from red grape skins and green tea leaves) and silver nanoparticles deposited by in situ reduction from a silver nitrate aqueous solution. The presence of biomolecules – showing reducing ability to directly obtain in situ metallic silver – and silver nanoparticles was investigated by means of UV–vis spectroscopy, X-Ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FESEM). The antibacterial activity of the modified surfaces was tested against a multidrug resistant Staphylococcus aureus bacterial strain.

Genetics Home Reference: Russell-Silver syndrome

Science.gov (United States)

... Other Names for This Condition RSS Silver-Russell dwarfism Silver-Russell syndrome SRS Related Information How are ... M, Begemann M, Elbracht M. Epigenetic and genetic diagnosis of Silver-Russell syndrome. Expert Rev Mol Diagn. ...

Formation and Characterization of Silver Nanoparticle Composite with Poly(p-Br/F-phenylsilane).

Science.gov (United States)

Roh, Sung-Hee; Noh, Ji Eun; Woo, Hee-Gweon; Cho, Myong-Shik; Sohn, Honglae

2015-02-01

The one-pot production and structural characterization of composites of silver nanoparticles with poly(p-Br/F-phenylsilane), Br/F-PPS, have been performed. The conversion of Ag+ ions to stable Ag0 nanoparticles is mediated by the copolymer Br/F-PPS having both possibly reactive Si-H bonds in the polymer backbone and C-Br bonds in the substituents along with relatively inert C-F bonds. Transmission electron microscopy and field emission scanning electron microscopy analyses show the formation of the composites where silver nanoparticles (less than 30 nm of size) are well dispersed over the Br/F-PPS matrix. X-ray diffraction patterns are consistent with that for face-centered-cubic typed silver. The polymer solubility in toluene implys that the cleavage of C-Br bond and the Si-F dative bonding may not be occurred appreciably at ambient temperature. Nonetheless, thermogravimetric analysis data suggest that some sort of cross-linking could take place at high temperature. Most of the silver particles undergo macroscopic aggregation without Br/F-PPS, which indicates that the polysilane is necessary for stabilizing the silver nanoparticles.

A study of silver behavior in Gas-turbine High Temperature Gas-cooled Reactor

International Nuclear Information System (INIS)

Sawa, Kazuhiro; Tanaka, Toshiyuki

1995-11-01

A Gas-turbine High Temperature Gas-cooled Reactor (GT-HTGR) is one of the promising reactor systems of future HTGRs. In the design of GT-HTGR, behavior of fission products, especially of silver, is considered to be important from the view point of maintenance of gas-turbine. A study of silver behavior in the GT-HTGR was carried out based on current knowledge. The purposes of this study were to determine an importance of the silver problem quantitatively, countermeasures to the problem and items of future research and development which will be needed. In this study, inventory, fractional release from fuel, plateout in the primary circuit and radiation dose were evaluated, respectively. Based on this study, it is predicted that gamma-ray from plateout silver in gas-turbine system contributes about a half of total radiation dose after reactor shutdown. In future, more detail data for silver release from fuel, plateout behavior, etc. using the High Temperature Engineering Test Reactor (HTTR), for example, will be needed to carry out reasonable design. (author)

Nucleic acid nanomaterials: Silver-wired DNA

Science.gov (United States)

Auffinger, Pascal; Ennifar, Eric

2017-10-01

DNA double helical structures are supramolecular assemblies that are typically held together by classical Watson-Crick pairing. Now, nucleotide chelation of silver ions supports an extended silver-DNA hybrid duplex featuring an uninterrupted silver array.

Kuantitas dan kualitas telur ayam arab (Gallus turcicus silver dan gold

Directory of Open Access Journals (Sweden)

M. H. Yumna

2014-03-01

Full Text Available This research was conducted to examine egg quantity and quality of Silver and Gold Arabic chicken (Gallus turcicus. The materials used in this study were 30 Silver and 30 Gold Arabic chicken aged 8-9 months which had mean of initial body weight were 1,93±0,13 and 2,00±0,15 kg respectively. The method was experiment on two groups of Arabic chicken based on feather color (Silver and Gold. Data was analyzed by unpaired t test. The study shows that egg weight of Gold Arabic chicken (46.81±2.41 g was significantly heavier (P<0.01 than that of Silver Arabic chicken (42.75±2.22 g. However, there were no significant difference on egg number, egg index, yolk color eggs, yolk protein content, yolk fat content, and Haugh units among these two chickens. It could be concluded that Gold Arabic chicken could produce heavier egg weight than the Silver one although there were no differences on egg number, egg index, yolk color eggs, yolk protein content, yolk fat content, and Haugh units. The study suggests breeding Gold Arabic chickens due to its egg weight production. Keywords: Arabic chicken, feather color, quantity and quality eggs

Antibacterial effect of silver nanofilm modified stainless steel surface

Science.gov (United States)