Silver

La puesta en vigor de las catacumbas romanas a lo largo del siglo XVIII, supuso un nuevo auge en el culto a las reliquias, que eran ampliamente solicitadas y vendidas a diferentes personas llegadas a Roma. Aunque generalmente eran vendidas en sencillas tecas ovales, también se creó un tipo de relicario de gran vistosidad y muy decorativo, pero de escaso valor económico, ya que estaban labrados en una fina chapa de plata que se aplicaba sobre una estructura de madera. Numerosos son los ejemplares de este tipo que se conservan en iglesias de la Península, siendo tal su éxito que se imitaron en talleres hispanos, como Zaragoza o Córdoba.

The impulse that experience the Roman catacombs throughout the eighteen century, supposed a new height in the cult to the relics, that widely were asked for and sold to different people who arrived to Roma. Although usually they were sold in simple oval thecas, also was created a type of reliquary very showy and ornamental, but of little economic value, because they were wrought with a fine plate of silver, that was applied on a wood structure. There are many reliquaries of this type in Spanish churches, being so its success which they were imitated in Hispanic workshops, as Saragossa or Cordova.

Lysosomes of embryonic rat fibroblasts cultivated in vitro normally contain heavy metals, as shown with a modified sulfide-silver method (SSM). Cultures which received lead added to the cultivation medium showed an enhanced SSM-positivity. However, since the SSM demonstrates several different heavy metals the sulfides of which are weakly soluble in water, it was not possible to distinguish between naturally occurring heavy metals-largely iron-and added lead (supposed to have been taken up by the cells). By treating the cells with a 0.2 M TCA solution after an initial exposure to HS-it was possible to dissolve FeS without affecting the PbS to any noticeable extent. When subsequently the development process of the SSM was applied to the cells, no metals could be demonstrated in the control cells whereas those exposed to lead showed presence of granules, most of which were identical with lysosomes as visualized with a Gomori type reaction. A lysosomal uptake of lead could thus be demonstrated with the modified SSM when combined with a simple dissolving process.

1. The effect of pH on the buoyant density of the complexes of Ag+ with DNA has been studied using 3H-labeled human DNA and several bacterial DNAs to determine the conditions necessary for the maximum resolution of compositional heterogeneity. In neutral CS2SO4 density gradients, Ag+ complexes with (G - C)-rich components are always denser than those with (A - T)-rich components, since (G - C)rich DNAs have a larger affinity for Ag+ than (A - T)-rich DNAs and their complexes are denser than (A - T)-rich complexes. In alkaline (pH greater than 9) CS2SO4 gradients, the buoyant density of the Ag+ - DNA complex is not a simple function of base composition. The Ag+ affinity of (A - T)-rich DNA is larger than that of (G - C)-rich DNA but the density of a (G - C)-rich complex is larger. Thus the ordering of the buoyant density changes depends on the amount of added Ag+. 2. The problem of resolving the density heterogeneity within a tracer DNA, and minor components of DNA, is explored and u...

Synthesis of metallic and semiconductor nanoparticles through physical and chemical routes has been extensively reported. However, green synthesized metal nanoparticles are currently in the limelight due to the simplicity, cost-effectiveness and eco-friendliness of their synthesis. This study explored the use of aqueous leaf extract of Costus afer in the synthesis of silver nanoparticles (CA-AgNPs). The optical and structural properties of the resulting silver nanoparticles were studied using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infra-red spectrophotometer (FTIR). TEM images of the silver nanoparticles confirmed the existence of monodispersed spherical nanoparticles with a mean size of 20 nm. The FTIR spectra affirmed the presence of phytochemicals from the Costus afer leaf extract on the surface of the silver nanoparticles. The electrochemical characterization of a CA-AgNPs/multiwalled carbon nanot...

Hydrogen gas can be produced by electrohydrogenesis in microbial electrolysis cells (MECs) at greater yields than fermentation and at greater energy efficiencies than water electrolysis. It has been assumed that a membrane is needed in an MEC to avoid hydrogen losses due to bacterial consumption of the product gas. However, high cathodic hydrogen recoveries (78 ( 1% to 96 ( 1%) were achieved in an MEC despite the absence of a membrane between the electrodes (applied voltages of 0.3 < E ap < 0.8 V; 7.5 mS/cm solution conductivity). Through the use of a membrane-less system, a graphite fiber brush anode, and close electrode spacing, hydrogen production rates reached a maximum of 3.12 ( 0.02 m 3 H 2 /m 3 reactor per day (292 ( 1 A/m 3 ) at an applied voltage of E ap ) 0.8 V. This production rate is more than double that obtained in previous MEC studies. The energy efficiency relative to the electrical input decreased with applied voltage from 406 ( 6% (E ap ) 0.3 V) to 194 ( 2% (E ap ) 0.8 V). Overall energy efficiency relative to both E ap and energy of the substrate averaged 78 ( 4%, with a maximum of 86 ( 2% (1.02 ( 0.05 m 3 H 2 /m 3 day, E ap ) 0.4 V). At E ap ) 0.2 V, the hydrogen recovery substantially decreased, and methane concentrations increased from an average of 1.9 ( 1.3% (E ap ) 0.3-0.8 V) to 28 ( 0% of the gas, due to the long cycle time of the reactor. Increasing the solution conductivity to 20 mS/ cm increased hydrogen production rates for E ap ) 0.3-0.6 V, but consistent reactor performance could not be obtained in the high conductivity solution at E ap > 0.6 V. These results demonstrate that high hydrogen recovery and production rates are possible in a single chamber MEC without a membrane, potentially reducing the costs of these systems and allowing for new and simpler designs.

The four human IgG isotypes are highly conserved in amino acid sequence, but show differential ability to activate complement (C'): IgG3 and IgGl are very active. IgG2 is active under certain conditions, and IgG4 is inactive. Although the second constant domain (C,2) is critical for C' activation, the individual amino acids that confer isotype-specific activity have not been identified. We have generated a series of mutants between IgG2 and IgG3, resulting in the exchange of the four N-terminal and six C-terminal polymorphic residues within C"2. Mutants containing the N-terminus of the C,2 of IgG3 were as effective as wildtype IgG3 in Clq binding, Cl activation and terminal complex (MAC) formation, but had reduced ability to effect C/-mediated lysis. IgG2 and mutants containing the N-terminal portion of the CH2 of IgG2 were reduced compared to IgG3 in activating Cl, binding Clq and inducing assembly of the MAC, and were inactive in mediating lysis of target cells. Thus, the amino acid sequence differences in the N-terminus of C,,2 play a critical role in determining the relative abilities of IgG2 and IgG3 to bind Clq and activate the C' cascade although additional residues of C,2 must be involved in mediating optimal target cells lysis. The sequence of the N-terminus of C,2 was less critical in determining C4 and C3 binding. Characterization of domain exchange mutants suggests that intermediate steps may be partly dependent on domains other than C,2. IgGs that do not direct target cell lysis nevertheless activate intermediate steps in the pathway, which may contribute to immune complex-associated disorders. pi;, 1997 Elsevier Science Ltd. All rights reserved.

The efficacy of antimicrobial central venous catheters (CVCs) remains questionable. In this network meta-analysis, we aimed to assess the comparative efficacy of antimicrobial CVC impregnations in reducing catheter-related infections in adults. We searched 4 electronic databases (Medline, the Cochrane Central Register of Controlled Trials, Embase, CINAHL) and internet sources for randomized controlled trials, ongoing clinical trials, and unpublished studies up to August 2016. Studies that assessed CVCs with antimicrobial impregnation with nonimpregnated catheters or catheters with another impregnation were included. Primary outcomes were clinically diagnosed sepsis, catheter-related bloodstream infection (CRBSI), and all-cause mortality. We performed a network meta-analysis to estimate risk ratio (RR) with 95% confidence interval (CI). Sixty studies with 17255 catheters were included. The effects of 14 impregnations were investigated. Both CRBSI and catheter colonization were the mo...

We analyze the price behavior of the main precious metals-gold, silver, platinum and palladium-before, during and in the aftermath of the 2007-08 financial crisis. Using the mildly explosive/multiple bubble technology developed by Phillips, Shi and Yu (2015, International Economic Review 56(4), 1043-1133), we find significant, short periods of mildly explosive behavior in the spot and futures prices of all four metals. Fewer periods are detected using exchange-rate adjusted prices, and almost none when deflated prices are used. We assess whether these findings are indicative of bubble behavior. Convenience yield is shown to have little efficacy in this regard, while other fundamental proxy variables and position data offer only very limited evidence against prices having been anything other than fundamentals-driven. Possible exceptions are in gold in the run-up to the highpoint of the financial crisis, and in silver and palladium around the launch of specific financial products. Some froth, however, is reported and discussed for each metal.

In this letter, we report the design and fabrication of different metal patterns for the realization of spatially controlled hydrophobic/hydrophilic regions with micrometer resolution. The fabrication procedure, based on a combination of lithographic techniques and wet-chemistry reactions (namely, spontaneous Galvanic displacement reactions) is reliable, undemanding, and highly versatile, allowing the achievement of precise spatial control along with the use of a wide variety of different materials. Jani, H.; Plessis, J. D.; Coloe, P. J.; Bhargava, S. K. Adv. Mater. 2008, 20, 717-723. (c) Liang, H. P.; Zhang, H. M.; Hu, J. S.; Guo, Y. G.; Wan, L. J.; Bai, C. L. Angew.

Silver nanoparticles exhibit antibacterial properties via bacterial inactivation and growth inhibition. The mechanism is not yet completely understood. This work was aimed at elucidating the effect of silver nanoparticles on inactivation of Escherichia coli, by studying particle-particle interactions in aqueous suspensions. Stable, molecularly capped, positively or negatively charged silver nanoparticles were mixed at 1 to 60 lg mL À1 with suspended E. coli cells to examine their effect on inactivation of the bacteria. Gold nanoparticles with the same surfactant were used as a control, being of similar size but made up of a presumably inert metal. Log reduction of 5 log 10 and complete inactivation were obtained with the silver nanoparticles while the gold nanoparticles did not show any inactivation ability. The effect of molecularly capped nanoparticles on E. coli survival was dependent on particle number. Log reduction of E. coli was associated with the ratio between the number of nanoparticles and the initial bacterial cell count. Electrostatic attraction or repulsion mechanisms in silver nanoparticle-E. coli cell interactions did not contribute to the inactivation process.

Extremely stable, peptide-capped gold nanoparticles with two different biomolecular recognition motifs expressed on their surface have been prepared, and their specific and selective binding to artificial, DNA-modified target particles and to DNA and protein microarrays has been demonstrated. Stabilization and biofunctionalization has been achieved in a single preparative step starting with citrate-stabilized gold hydrosols and a derivatization cocktail of peptide-capping ligands, which carry the functionalities of choice.

Bifunctional DNA oligonucleotides serve as templates for chromophoric silver clusters and as recognition sites for target DNA strands, and communication between these two components is the basis of an oligonucleotide sensor. Few-atom silver clusters exhibit distinct electronic spectra spanning the visible and near-infrared region, and they are selectively synthesized by varying the base sequence of the DNA template. In these studies, a 16-base cluster template is adjoined with a 12-base sequence complementary to the target analyte, and hybridization induces structural changes in the composite sensor that direct the conversion between two spectrally and stoichiometrically distinct clusters. Without its complement, the sensor strand selectively harbors ~7 Ag atoms that absorb at 400 nm and fold the DNA host. Upon association of the target with its recognition site, the sensor strand opens to expose the cluster template that has the binding site for ~11 Ag atoms, and absorption at 720 nm with relatively strong emission develops in lieu of the violet absorption. Variations in the length and composition of the recognition site and the cluster template indicate that these types of dual-component sensors provide a general platform for near-infrared-based detection of oligonucleotides in challenging biological environments.

The National Institute for Occupational Safety and Health (NIOSH) and European Norms (ENs) employ different test protocols for evaluation of air-purifying particulate respirators commonly referred to as filtering facepiece respirators (FFR). The relative performance of the NIOSH-approved and EN-certified 'Conformité Européen' (CE)-marked FFR is not well studied. NIOSH requires a minimum of 95 and 99.97% efficiencies for N95 and P100 FFR, respectively; meanwhile, the EN requires 94 and 99% efficiencies for FFRs, class P2 (FFP2) and class P3 (FFP3), respectively. To better understand the filtration performance of NIOSH-and CE-marked FFRs, initial penetration levels of N95, P100, FFP2 and FFP3 respirators were measured using a series of polydisperse and monodisperse aerosol test methods and compared. Initial penetration levels of polydisperse NaCl aerosols [mass median diameter (MMD) of 238 nm] were measured using a method similar to the NIOSH respirator certification test method. Monodisperse aerosol penetrations were measured using silver particles for 4-30 nm and NaCl particles for 20-400 nm ranges. Two models for each FFR type were selected and five samples from each model were tested against charge neutralized aerosol particles at 85 l min 21 flow rate. Penetrations from the 238 nm MMD polydisperse aerosol test were <1% for N95 and FFP2 models and <0.03% for P100 and FFP3 models. Monodisperse aerosol penetration levels showed that the most penetrating particle size (MPPS) was in the 30-60 nm range for all models of FFRs tested in the study. Percentage penetrations at the MPPS were <4.28, <2.22, <0.009 and <0.164 for the N95, FFP2, P100 and FFP3 respirator models, respectively. The MPPS obtained for all four FFR types suggested particle capturing by electrostatic mechanism. Liquid isopropanol treatment of FFRs shifted the MPPS to 200-300 nm and dramatically increased polydisperse as well as monodisperse aerosol penetrations of all four FFR types indicating that all the four FFR types share filtration characteristics of electret filters. Electrostatic charge removal from all four FFR types also increased penetration levels of 400-1000 nm range particles. Particle penetration data obtained in this study showed that the eight models of NIOSH-approved N95 and P100 and CE-marked FFP2 and FFP3 respirators used in this study provided expected levels of laboratory filtration performance against nanoparticles.

In this article, we report the results of the extent of interaction as well as the formation of a bioconjugate of human hemoglobin (Hb) with silver (Ag). The complexation process and conformational changes are characterized using different spectroscopic and microscopic techniques. The UV-vis study demonstrates the perturbation of the soret/heme band and generates conformational heterogeneity within the heme group in the presence of silver. A fluorescence study suggests that the Tryptophan (Trp) residues of Hb are in a more polar environment after conjugation. Initial fluorescence enhancement with addition of silver is due to metalenhanced fluorescence. Moreover, the fluorescence quenching after the formation of the Hb-Ag bioconjugate follows the modified Stern-Volmer (S-V) plot. The S-V plot along with the time-resolved fluorescence study indicates the presence of both static and dynamic types of quenching. In addition, the reduction potential values of the entities (Hb-heme, Ag + , and Trp) indicate the possible electron transfer. The secondary structure calculation from CD and FTIR spectra indicate R-helix to -sheet conversion, and unfolding of Hb is also responsible for the bioconjugate formation. In addition, FE-SEM, phase contrast inverted microscopy (PCIM) images demonstrate the formation of the silver-protein bioconjugate. The overall data show that there is a change in the secondary as well as the tertiary structure of Hb after conjugation with silver.

The aim of this work is to produce and investigate silver polymer nanocomposites formed by electron beam evaporation on PMMA-PET structure. It is demonstrated that the surface plasmon resonance (SPR) absorption peak of nanostructured silver is near 425 nm and shifts to the longer waves (up to 600 nm) and corresponding band broadening with increase of silver film thickness. The different ultrathin silver-polymer nanocomposites color filters as a result of plasmon resonance shifting in the UV-VIS wavelength region were produced. The developed method provided a simple and practical solution to create silver nanostructures in polymer matrix. Keywords: polymethylmethacrylate (PMMA), polyethylene terephthalate (PET), silver, nanocomposites, plasmonic optic, AFM.

A context-semantic analysis of the use of the word ‘silver’ (Av. ərəzata-) in Avestan texts is carried out in the paper. There are 12 cases of its usage (Yasna 10.17; Yashts 5.129; 10.112, 125; 17.14; 19.67; Videvdat 7.75; 8.88; 14.11 (2); Aogemadaēca 17; 84). The analysis shows that the word ‘silver’ is used in several different semantic contexts, such as the ritual of Haoma (Yasna 10.17) and the purifying ceremony (Videvdat 7.75). Silver is associated with the concept of ‘brilliance’ and is represented in the descriptions of its various manifestations. The brilliance of silver is associated
with the idea of the sun rays manifesting themselves in the image of Mithra (Yasht 10.112), and of lunar splendour (Yasht 10.125). Beaver-skin robe of the goddess Arədvī Sūrā Anāhitā glistens like “silver (and) gold” (Yasht 5.129). The connection of silver with water is confirmed by its inclusion in Iranian hydronymics (Yasht 19.67). The combination “silver (and) gold” may be a metonymic designation for the concept of wealth (Yasht 5.129; 17.14; Aogemadaēca 84). The value of silver was lower than that of gold (Yasna 10.17; Yasht 10.125; Videvdat 7.74–75, 8.87–88; 14.11). Silver
is mentioned in the descriptions of the other world: the pantries of the righteous are filled with silver (Yasht 17.14), and the righteous deceased have silver clothes (Aogemadaēca 17).

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Medical-grade poly(vinyl chloride) (PVC) was chemically modified to study how the incorporation of monovalent silver influences Pseudomonas aeruginosa adhesion and colonization. The modification investigated consisted of a radio frequency-oxygen (RF-O 2 ) glow discharge pre-functionalization, followed by a two-step wet-treatment in sodium hydroxide and silver nitrate solutions. X-ray photoelectron spectroscopy (XPS) analysis and contact angle measurements were used to investigate the chemical nature and surface wettability of the films following each step of the modification. XPS analysis proved that the RF-O 2 plasma pre-functionalization of native PVC reproducibly increased the amount of functional groups representative of PVC additives, including ether/alcohol, esters and carboxyl groups. More specifically, we demonstrated that the O2 % CQO groups representative of the phthalic ester and zinc carboxylate additives identified for native PVC increased by two-fold following the RF-O 2 plasma pre-functionalization step. Although RF-O 2 pre-functionalization did not have an effect on the silver content of the NaOH/AgNO 3 treated substrates, such a modification was necessary for biomaterial products that did not have reproducible surfaces amongst production lots. XPS analysis also demonstrated that saponification with sodium hydroxide (NaOH) of esters, like those of the phthalic ester additives of PVC is a simple, irreversible method of hydrolysis, which produced sodium carboxylate and sodium phthalate salts. Exposure of native PVC to NaOH resulted in an increased surface hydrophilicity (from ca 90 to ca 60 ) due to dechlorination. XPS analysis following further incubation in silver nitrate demonstrated that silver ions can be trapped when the sodium of sodium carboxylate is replaced by silver after performing a second treatment with a monovalent silver-containing solution. The creation of silver salt on native PVC resulted in an ultra-hydrophobic (>120 ) surface. The chemical modifications using NaOH and AgNO 3 wet treatments completely inhibited bacterial adhesion of four strains of P. aeruginosa to both native and oxygen-pre-functionalized PVC, and efficiently prevented colonization over longer periods (72 h). Our results suggest that surface modifications that incorporate silver ions would be extremely effective at reducing bacterial colonization to medical devices. r

This study represents a novel template demonstration of a glucose biosensor based on mercaptophenyl boronic acid (MBA) terminated Ag@AuNPs/graphene oxide (Ag@AuNPs-GO) nanomaterials. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) method. The TEM image shows that Ag@AuNPs in the nanocomposite is in the range of diameters of 10-20 nm. The nanocomposite was used for the determination of glucose through the complexation between boronic acid and diol groups of glucose. Thus, a novel glucose biosensor was further fabricated by immobilizing glucose oxidase (GOD) into MBA terminated Ag@AuNPs-GO nanocomposite film (MBA-Ag@AuNPs-GO). The linearity range of glucose was obtained as 2-6 mM with detection limit of 0.33 mM. The developed biosensor was also applied successfully for the determination of glucose in blood samples. The concentration value of glucose in blood samples was calculated to be 1.97 ± 0.002 mM from measurements repeated for six times.

In the present study we have synthesized a novel amphiphilic porphyrin and its Ag(II) complex through modification of water-soluble porphyrinic structure in order to increase its lipophilicity and in turn pharmacological potency. New cationic non-symmetrical meso-substituted porphyrins were characterized by UV-visible, electrospray ionization mass spectrometry (ESI-MS), 1 H NMR techniques, lipophilicity (thin-layer chromatographic retention factor, R f ), and elemental analysis. The key toxicological profile (i.e. cytotoxicity and cell line-(cancer type-) specificity; genotoxicity; cell cycle effects) of amphiphilic Ag porphyrin was studied in human normal and cancer cell lines of various tissue origins and compared with its water-soluble analog. Structural modification of the molecule from water-soluble to amphiphilic resulted in a certain increase in the cytotoxicity and a decrease in cell line-specificity. Importantly, Ag(II) porphyrin showed less toxicity to normal cells and greater toxicity to their cancerous counterparts as compared to cisplatin. The amphiphilic complex was also not genotoxic and demonstrated a slight cytostatic effect via the cell cycle delay due to the prolongation of S-phase. As expected, the performed structural modification affected also the photocytotoxic activity of metalfree amphiphilic porphyrin. The ligand tested on cancer cell line revealed a dramatic (more than 70-fold) amplification of its phototoxic activity as compared to its water-soluble tetracationic metal-free analog. The compound combines low dark cytotoxicity with 5 fold stronger phototoxicity relative to Chlorin e 6 and could be considered as a potential photosensitizer for further development in photodynamic therapy.

Figure 4. (a) UV/Vis absorption spectra for Au nanoparticles, Fe 2 O 3, Au-Fe 2 O 3 nanoflakes, respectively; (b) IPCE, (c) band gap determination from a (i ph hu) 1/2 vs. photon energy (hu) plot, (d) photocurrent at 360 nm at applied potential of 1.5 V RHE in 1 m KOH solution for Fe 2 O 3 and Au-Fe 2 O 3 nanoflakes.

Eighty freshly extracted teeth were endodontically prepared and filled with gutta-percha and either a zinc oxide-eugenol-based sealer or AH26 to determine what effect these sealers, with widely differing properties, would have on apical microleakage after either immediate or delayed dowel space preparation. The teeth were randomly assigned to 1 of 4 groups, and the post space was made either immediately after filling or after being stored in 100% humidity for 1 wk. They were then immersed in a 2% methylene blue solution under vacuum, washed, and split longitudinally. The extent of dye penetration was read by five independent observers and the results analyzed. The only significant difference was in the delayed preparation group with zinc oxide-eugenol sealer, which showed greater leakage than the other groups.

In this study, the recent trends for optical coatings in glass industries have been explored for the variety of climate dependent applications. Different coated glazings have been presented with their optical and thermal characteristics. A comparative analysis among types of coated products is also performed. It has been observed that for warm climate it is necessary to block near infra red portion of sunlight to reduce solar heat gain through windows. On the other hand, for cold climate it is necessary to allow the whole portion of light and it is necessary to block the IR radiation from escaping out to keep the interior space warm. For this purpose, Ag or Ag-alloy metallic thin film meet the requirements but they reduce visible transmittance as well. So for increasing visible transmittance, a dielectric layer of high refractive index is required. Here a variety of dielectric layers are studied. Finally for reaching the goal of low energy buildings in both warm and cold climates, appropriate optical coatings for architectural flat glass have been recommended. © 2008 Asian Network for Scientific Information.

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Temperature dependencies of thermal expansion coefficients for the alloys of Pd-Ag, Pd-Cu and Pd-Co binary systems were measured at temperatures up to 900•Ž, with heating and cooling rates of 5•Ž/min. The coefficient of thermal expansion of alloys with no transformation in the temperature range of interest in porcelain firing was well approximated by a linear equation of temperature. The constants in the equation were shown as a function of the weight for the added element. Thermal expansion of the palladium-based alloy with no transformation was well estimated at any temperature range and at any composition by using the constants represented here. The coefficients of thermal expansion before and after order-disorder transformation and magnetic transformation were measured in Pd-Cu and Pd-Co alloys, respectively. The results suggest that transient and residual stresses in porcelain-fused-to-metal restorations can be effectively controlled by making use of transformation of the alloy.

This paper reports an effective method to enhance the surface plasmon resonance (SPR) on Ag films by using a thin Ni seed layer assisted deposition. Ag films with a thickness of about 50 nm were deposited by electron beam evaporation above an ultrathin Ni seed layer of ϳ2 nm on both silicon and quartz substrates. The root-mean-square (rms) surface roughness and the correlation length have been reduced from >4 nm and 28 nm for a pure Ag film to ϳ1.3 and 19 nm for Ag/Ni films, respectively. Both experimental and simulation results show that the Ag/Ni films exhibit an enhanced SPR over the pure Ag film with a narrower full width at halfmaximum. Ag films with a Ge seed layer have also been prepared under the same conditions. The surface roughness can be reduced to less than 0.7 nm, but narrowing of the SPR curve is not observed due to increased absorptive damping in the Ge seed layer. Our results show that Ni acts as a roughness-diminishing growth layer for the Ag film while at the same time maintaining and enhancing the plasmonic properties of the combined structures. This points toward its use for low-loss plasmonic devices and optical metamaterials applications.

We synthesized 25,26,27,28-tetrakis(11-sulfanylundecyloxy)calix[4]arene (CALIX) sensitive to dopamine and confirmed its structure by 1 H NMR and mass spectrometry. Chemisorption of CALIX molecules or their mixtures with 1-dodecanethiols (DDT) or hexadecanethiols (HDT) resulted in formation of compact low permeable monolayers as revealed by cyclic voltammetry at presence of redox probe [Fe(CN) 6 ] 3−/4− . These self-assembled monolayers (SAMs) served as sensor for dopamine. Thickness shear mode acoustic method (TSM) has been used for study the interaction of dopamine with calixarene SAM. The admittance spectra of TSM transducer have been measured and used for simultaneous determination of the changes in series resonant frequency, f S , and motional resistance, R m , respectively. Addition of dopamine resulted in substantial decrease of f S and increase of R m , which is evidence on increased viscoelastic contribution into the acoustic properties of the sensing layer. Limit of detection (LOD) for dopamine was 50 pM, which is much better in comparison with so far reported lowest LOD for dopamine-sensitive electrochemical sensors (20 nM). The sensor allowed discrimination between dopamine and epinephrine.

Improved positively charged nanoparticles are described to provide a simplified SERS substrate for DNA detection. Complete flocculation of the nanoparticles is prevented due to the controlled analyte induced aggregation. This provides a stable aggregation state which significantly extends the analysis window simplifying DNA detection by SERS.

A green synthesis of highly stable gold and silver nanoparticles (NPs) using arabinoxylan (AX) from ispaghula (Plantago ovata) seed husk is being reported. The NPs were synthesized by stirring a mixture of AX and HAuCl 4 ·H 2 O or AgNO 3 , separately, below 100 • C for less than an hour, where AX worked as the reducing and the stabilizing agent. The synthesized NPs were characterized by surface plasmon resonance (SPR) spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The particle size was (silver: 5-20 nm and gold: 8-30 nm) found to be dependent on pH, temperature, reaction time and concentrations of AX and the metal salts used. The NPs were poly-dispersed with a narrow range. They were stable for more than two years time.

In this study an effective nanocomposite antimicrobial agent for wool fabric was introduced. The silver loaded nano TiO 2 as a nanocomposite was prepared through UV irradiation in an ultrasonic bath. The nanocomposite was stabilized on the wool fabric surface by using citric acid as a friendly cross-linking agent. The treated wool fabrics indicated an antimicrobial activity against both Staphylococcus aureus and Escherichia coli bacteria. Increasing the concentration of Ag/TiO 2 nanocomposite led to an improvement in antibacterial activities of the treated fabrics. Also increasing the amount of citric acid improved the adsorption of Ag/TiO 2 on the wool fabric surface leading to enhance antibacterial activity. The EDS spectrum, SEM images, and XRD patterns was studied to confirm the presence of existence of nanocomposite on the fabric surface. The role of both cross-linking agent and nanocomposite concentrations on the results was investigated using response surface methodology (RSM).

We have developed a polyaniline/carboxy-functionalized multiwalled carbon nanotube (PAn/MWCNTCOOH) nanocomposite by blending the emeraldine base form of polyaniline (PAn) and carboxy-functionalized multiwalled carbon nanotubes (MWCNT) in dried dimethyl sulfoxide (DMSO) at room temperature. The conductivity of the resulting PAn/MWCNTCOOH was 3.6 × 10 −3 S cm −1 , mainly as a result of the protonation of the PAn with the carboxyl group and the radical cations of the MWCNT fragments. Horseradish peroxidase (HRP) was immobilized within the PAn/MWCNTCOOH nanocomposite modified Au (PAn/MWCNTCOOH/Au) electrode to form HRP/PAn/MWCNTCOOH/Au for use as a hydrogen peroxide (H 2 O 2 ) sensor. The adsorption between the negatively charged PAn/MWCNTCOOH nanocomposite and the positively charged HRP resulted in a very good sensitivity to H 2 O 2 and an increased electrochemically catalytical current during cyclic voltammetry. The HRP/PAn/MWCNTCOOH/Au electrode exhibited a broad linear response range for H 2 O 2 concentrations (86 M-10 mM). This sensor exhibited good sensitivity (194.9 A mM −1 cm −2 ), a fast response time (2.9 s), and good reproducibility and stability at an applied potential of −0.35 V. The construction of the enzymatic sensor demonstrated the potential application of PAn/MWCNTCOOH nanocomposites for the detection of H 2 O 2 with high performance and excellent stability.

We report on chemically prepared silver nanowires (diameters around 100 nm) sustaining surface plasmon modes with wavelengths shortened to about half the value of the exciting light. As we find by scattered light spectroscopy and near-field optical microscopy, the nonradiating character of these modes together with minimized damping due to the well developed wire crystal structure gives rise to large values of surface plasmon propagation length and nanowire end face reflectivity of about 10 m and 25%, respectively. We demonstrate that these properties allow us to apply the nanowires as efficient surface plasmon Fabry-Perot resonators.

Work has been intensified around the integration of textile and measurement technology for physiological measurements in the last years. As a result nowadays it is possible to find available commercial products for cardiovascular personal healthcare monitoring. Most of the efforts have been focused in the acquisition of EKG for cardiovascular monitoring where textile electrodes have shown satisfactory performance. Electrical Bioimpedance is another type of physiological measurement that can be used for personal healthcare monitoring where the integration and the performance of the textile electrodes has not been investigated that thoroughly. In this work, the influence of the textile electrodes on the measurements and on the estimation of the Cole (R(0), R(infinity), f(C) and alpha) and body composition (TBW, ICW, ECW and FFM) parameters has been especially addressed. Complex Spectroscopy 4-electrode wrist-to-ankle electrical bioimpedance measurements taken with conventional Ag/AgCl...