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We have studied the petrochemistry of degraded bones and sediment from the interior of four ossuaries (burial boxes) discovered in what is (arguably) believed to be the 1st century CE family tomb of the high priest Caiaphas (herewith Cft) in Jerusalem. During the course of the 1990 excavation, among other artifacts (e.g., a coin found in a skull) two iron nails were discovered. One of the nails was inside an ossuary, the other on the floor of one of the nearby “kokhim” (burial niches) which contained Ossuaries 5 and 6. According to the Israel Antiquities Authority (IAA) everything in the burial cave can be accounted for today except the iron nails “which have been misplaced”, this without being properly recorded or photographed. Investigative journalist Simcha Jacobovici believes that he has located the nails in the artifacts collection of the Anthropology laboratory at Tel Aviv University. The IAA, however, has stated that the lost nails from the Cft have nothing to do with the nails found at the university and the latter nails must have a different provenance. Wherever lies the truth, the presence of two nails in the Cft is of profound interest because in the New Testament the high priest Caiaphas was responsible for passing Jesus to the Romans who then sent him to the cross. The possibility that the nails were used in a crucifixion on the one hand and can be connected to Caiaphas the high priest on the other is, to say the least, interesting and potentially monumental. Aware of the controversy but also of the importance of the two unprovenanced nails we have investigated the materials which have invaded the interiors of the Cft ossuaries and in a similar manner materials that have adhered to the two unprovenanced nails. Employing geochemical and petrochemical Scanning Electron Microscope (SEM-EDX), X-ray diffraction (XRD) and δ18O and δ13C isotope analyses we have found that the organic and inorganic materials flushed into the interior of the Cft but also those that have adhered to the two unprovenanced nails possess and display many identical, and what can also be termed unique chemical and physical characteristics. Based on the collective evidence we conclude, with considerable confidence, that the unprovenanced nails are the lost nails excavated from the Caiaphas family tomb in 1990 and furthermore that these nails were used in a crucifixion.

The coupling of a superconductor to a different material often results in a system with unconventional superconducting properties. A conventional superconductor is a perfect diamagnet expelling magnetic fields out of its volume, a phenomenon known as Meissner effect. Here, we show that the simple adsorption of a monolayer of chiral molecules, which are non-magnetic in solution, onto the surface of a conventional superconductor can markedly change its diamagnetic Meissner response. By measuring the internal magnetic field profile in superconducting Nb thin films under an applied transverse field by low-energy muon spin rotation spectroscopy, we demonstrate that the local field profile inside Nb is considerably modified upon molecular adsorption in a way that also depends on the applied field direction. The modification is not limited to the chiral molecules/Nb interface, but it is long ranged and occurs over a length scale comparable to the superconducting coherence length. Zero-field muon spin spectroscopy measurements in combination with our theoretical analysis show that odd-frequency spin-triplet states induced by the chiral molecules are responsible for the modification of the Meissner response observed inside Nb. These results indicate that a chiral molecules/superconductor system supports odd-frequency spin-triplet pairs due to the molecules acting as a spin active layer and therefore they imply that such system can be used as a simpler alternative to superconductor/ferromagnet or superconductor/topological insulator hybrids for the generation and manipulation of unconventional spin-triplet superconducting states., 13 pages and 5 figures plus Appendixes

A highly active FeSe2 electrocatalyst for durable overall water splitting was prepared from a molecular 2Fe-2Se precursor. The as-synthesized FeSe2 was electrophoretically deposited on nickel foam and applied to the oxygen and hydrogen evolution reactions (OER and HER, respectively) in alkaline media. When used as an oxygen-evolution electrode, a low 245 mV overpotential was achieved at a current density of 10 mA cm-2 , representing outstanding catalytic activity and stability because of Fe(OH)2 /FeOOH active sites formed at the surface of FeSe2 . Remarkably, the system is also favorable for the HER. Moreover, an overall water-splitting setup was fabricated using a two-electrode cell, which displayed a low cell voltage and high stability. In summary, the first iron selenide material is reported that can be used as a bifunctional electrocatalyst for the OER and HER, as well as overall water splitting.

Cu2+-functionalized carbon nitride nanoparticles (Cu2+–g-C3N4 NPs), ∼200 nm, and Cu2+–carbon dots (Cu2+–C-dots), ∼8 nm, act as horseradish peroxidase-mimicking catalysts. The nanoparticles catalyze the generation of chemiluminescence in the presence of luminol/H2O2 and catalyze the oxidation of dopamine by H2O2 to form aminochrome. The Cu2+–g-C3N4-driven generation of chemiluminescence is used to develop a H2O2 sensor and is implemented to develop a glucose detection platform and a sensor for probing glucose oxidase. Also, the Cu2+–C-dots are functionalized with the β-cyclodextrin (β-CD) receptor units. The concentration of dopamine, at the Cu2+–C-dots’ surface, by means of the β-CD receptor sites, leads to a 4-fold enhancement in the oxidation of dopamine by H2O2 to yield aminochrome compared to that of the unmodified C-dots.

A systematic structural elucidation of the near-surface active species of the two remarkably active nickel phosphides Ni12P5 and Ni2P on the basis of extensive analytical, microscopic, and spectroscopic investigations is reported. The latter can serve as complementary efficient electrocatalysts in the hydrogen (HER) versus oxygen evolution reaction (OER) in alkaline media. In the OER Ni12P5 shows enhanced performance over Ni2P due to the higher concentration of nickel in this phase, which enables the formation of an amorphous NiOOH/Ni(OH)2 shell on a modified multiphase with a disordered phosphide/phosphite core. The situation is completely reversed in the HER, where Ni2P displayed a significant improvement in electrocatalytic activity over Ni12P5 owing to a larger concentration of phosphide/phosphate species in the shell. Moreover, the efficiently combined use of the two nickel phosphide phases deposited on nickel foam in overall electrocatalytic water splitting is demonstrated by a strikingly low cell v...

Migration of silver atoms from silver nano-particles selectively to a double-stranded poly(dG)-poly(dC) polymer leads to metallization of the DNA. As a result the DNA molecules become shorter and thicker (higher), as evident from the atomic force microscopy imaging analysis. The metalized molecules can be detected by transmission and scanning electron microscopy in contrast to the initial non-metalized ones.

Gallium-nitride (GaN) light detectors are sensitive to ultraviolet (UV) radiation below 365 nm wavelength due to their wide bandgap – 3.4 eV. However, the presence of impurities, especially surface traps, leads to slow relaxation rates and sub-bandgap response due to new energy levels. In the present work we offer utilizing these impurities to broad the spectral range up to the near-infrared (NIR) and modifying the surface of the photoresistors to enhance the response, the recovery time, and the repeatability by using several surface treatments such as plasma asher and the adsorption of organic molecules. The wide band response up to the NIR range was achieved by exciting the detector with a constant UV light intensity, resulting in a responsivity of 10–100 A/W. We ascribe the high sensitivity to visible and NIR wavelengths to a gating amplification effect caused by trapped charges. Owing to the band bending of energy levels, a large depletion layer is created on the surface of the GaN layer, effectively separating the surface conductivity from the bulk. These properties make the detector sensitive to changes on the surface, thus making it ideal for biological and chemical uses as well as for broadband light detectors.

International audience; The Levantine Aurignacian is a unique phenomenon in the local Upper Paleolithic sequence, showing greater similarity to the West European classic Aurignacian than to the local Levantine archaeological entities preceding and following it. Herewith we highlight another unique characteristic of this entity, namely, the presence of symbolic objects in the form of notched bones (mostly gazelle scapulae) from the Aurignacian levels of Hayonim Cave, Lower Galilee, Israel. Through both macroscopic and microscopic analyses of the items, we suggest that they are not mere cut marks but rather are intentional (decorative?) human-made markings. The significance of this evidence for symbolic behavior is discussed in its chrono-cultural and geographical contexts. Notched bones are among the oldest symbolic expressions of anatomically modern humans. However, unlike other Paleolithic sites where such findings were reported in single numbers, the number of these items recovered at Hayonim Cave is sufficient to assume they possibly served as an emblem of the Levantine Aurignacian.

The strikingly high catalytic performance and stability of manganese substituted cobalt oxide spinel (Mn

Metal decoration on the edges of highly faceted Cu2S semiconductor nanocrystals yields a family of nano-inorganic caged (NICed) hybrid semiconductor–metal nanoparticles. We present the growth of rhodium and of ruthenium–rhodium mixture to give Rh–Cu2S and RuRh–Cu2S hybrid nanoparticle cages, respectively. Transmission electron microscopy affirms the growth of the metals selectively on the nanocrystal edges within a narrow temperature window. The oxidation level of the metal frame could also be controlled during the reaction stages as characterized by X-ray photoelectron spectroscopy, providing additional variation for the hybrid nanoparticle cages. The synergistic electronic properties of the hybrid nanocages were observed on a single particle level using scanning tunneling spectroscopy. The various cage nanoparticles are also of interest as possible catalysts for metal and metal-oxide catalyzed reactions.

This article describes single-molecule force spectroscopy measurements of the interaction between individual amino acid residues and inorganic surfaces in an aqueous solution. In each measurement, there is an amino acid residue, lysine, glutamate, phenylalanine, leucine, or glutamine, and each represents a class of amino acids (positively or negatively charged, aromatic, nonpolar, and polar). Force-distance curves measured the interaction of the individual amino acid bound to a silicon atomic force microscope (AFM) tip with a silcon substrate, cut from a single-crystal wafer, or mica. Using this method, we were able to measure low adhesion forces (below 300 pN) and could clearly determine the strength of interactions between the individual amino acid residues and the inorganic substrate. In addition, we observed how changes in the pH and ionic strength of the solution affected the adsorption of the residues to the substrates. Our results pinpoint the important role of hydrophobic interactions among the amino acids and the substrate, where hydrophobic phenylalanine exhibited the strongest adhesion to a silicon substrate. Additionally, electrostatic interactions also contributed to the adsorption of amino acid residues to inorganic substrates. A change in the pH or ionic strength values of the buffer altered the strength of interactions among the amino acids and the substrate. We concluded that the interplay between the hydrophobic forces and electrostatic interactions will determine the strength of adsorption among the amino acids and the surface. Overall, these results contribute to our understanding of the interaction at the organic-inorganic interface. These results may have implications for our perception of the specificity of peptide binding to inorganic surfaces. Consequently, it would possibly lead to a better design of composite materials and devices.

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A successful methodology for obtaining hybrid films which allow thermal triggering and continuous, irreversible, control of their hydrophilicity/hydrophobicity nature was developed. Two types of poly(dimethylsiloxane)-silica (PDMS@SiO2) films were prepared for that purpose: A hydrophilic film in which the thermal treatment causes an irreversible gradual increase of hydrophobicity; and a hydrophobic film that turns more hydrophilic upon thermal treatment. The opposite directionality of the change is dictated by the film substrate, on which the same hybrid is deposited. In both cases the thermal treatment induced a phase separation which caused the change in hydrophobicity. The magnitude of change in hydrophilicity/hydrophobicity is continuously controllable in both types of films by either the temperature or heating time. The films were characterized before and after heating by a variety of methods, including contact angle (CA) measurements with the sessile drop and the tilting plate methods, and by X-ray photoelectron spectroscopy (XPS) analysis. A thorough kinetic study was carried out, following the progress of the changes in the wettability property of the surfaces. The kinetics analyses proved that the changes in the wettability in all cases are due to phase separation processes, the directionality of which is determined by the treatment of the substrate on which the films are deposited. By monitoring the change of wettability (ΔCA) at various temperatures, an Arrhenius plot was obtained from which the activation energy and Arrhenius pre-exponential factor for the phase separation were derived, corroborating the proposed mechanism. To the best of our knowledge, this is the first use of phase separation behavior of a hybrid film in order to apply irreversible, thermally controllable change of surface wettability, tailored to proceed in opposite directions, and the first kinetic study of such a process.

D. Porath, A. Kotlyar, and co-workers transform DNA to a conducting material by metalization through coating or chemical modifications, as described on page 4839. Specific and reversible metalization of poly(dG)-poly(dC) DNA by migration of atoms from silver nanoparticles to the DNA is demonstrated. As the transformation occurs gradually, novel, truly hybrid molecular structures are obtained, paving the way to their usage as nanowires in programmable molecular electronic devices and circuits.

The ultrathin peroxoantimonate coating of graphene oxide from hydrogen peroxide-rich solutions of hydroxoantimonate is demonstrated. An amorphous 1–2 nm Sb (V) oxide film is formed and can be further crystallized by exposure to an electron beam to give a 2–5 nm thick supported Sb 6 O 13 particulate coating. Heat treatment of the peroxoantimonate yielded different crystalline oxides, whereas in the presence of the graphene support only trigonal Sb (0) was produced by heat treatment in vacuum or an argon atmosphere. The graphene oxide support is essential for the formation of the Sb (0) phase and even in air a substantial elemental antimony was obtained. Whereas heat treatment of uncoated graphene oxide in an inert atmosphere produces reduced graphene oxide, the antimony oxide coated graphene oxide is not reduced by the heat treatment. Only after the supported antimony oxide is reduced to give the trigonal Sb (0) phase the graphene oxide was reduced by the heat treatment. The phases before and after the different heat treatments are characterized by electron and X-ray diffraction, thermal analysis, XPS studies, electron microscopy and wet chemistry.

In the course of our attempts to replace the traditional but environmentally disfavored organic solvents in organic processes by water, we studied the double bond isomerization of hydrophobic allylarenes, in aqueous microemulsions. The catalyst for these reactions was the rhodium-trichloride-Aliquat ® 336 ion pair encaged within hydrophobic silica sol–gel. During the entrapment of the rhodium compound, it was converted into supported catalytically active Rh(0) nanoparticles characterized by TEM and XPS studies. The transformations of the allylarenes to ( E )- and ( Z )-1-phenyl-1-propenes follows the first order rate law, and proved to be significantly affected by the electronic nature of the substrates and by the hydrophobicity of the sol–gel support. Upon completion of the isomerization the catalyst could be recovered and recycled at least six times without a decrease in the catalytic activity after the first catalytic run.

Probing electrochemical processes by mass spectrometry (EC/MS) is a developing field that benefits from the unmatched identification power of mass spectrometry and from the rapid transfer of electrochemical cell products to the mass spectrometer. Most of the current EC/MS efforts are directed towards the development of differential electrochemical mass spectrometry (DEMS) using the electro-ionization source for identification of volatile compounds, and towards the application of electrospray mass spectrometers for determination of semivolatile and nonvolatile products. The challenges in coupling mass spectrometry and electrochemistry are described, and different approaches to using the coupled system for diverse applications are reviewed, with emphasis on electrospray mass spectrometry. Reaction mechanism studies, diagnostic applications, and activity imaging of electrodes are demonstrated based on approaches that were devised in our laboratory.

Granular sodium percarbonate has been characterized by X-ray powder diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The O1s binding energy for the solvating hydrogen peroxide molecules is 535.8 eV. Sodium percarbonate is stabilized by sodium silicate and polyphosphate.

We describe two different pathways by which palladium-catalyzed Heck and Suzuki coupling reactions take place. When sol–gel entrapped palladium acetate was used as a catalyst, the reactions proceed by the formation of metallic nanoparticles. Such particles were already formed during the immobilization of the palladium salt. Upon application of palladium derivatives of proline, tyrosine, or alanine, either in their homogeneous or in their sol–gel entrapped version, no Pd0 particles could be detected, even when the couplings were carried out in boiling mesitylene (161 °C) or during prolonged reaction periods (48 h). The reactions in the presence of the amino acid derivatives proceeded at a higher rate than those by the entrapped palladium acetate. The existence of palladium nanoparticles was investigated with the aid of high-resolution scanning transmission electron microscopy equipped with energy dispersive X-ray spectroscopy, as well as by X-ray photoelectron spectroscopy.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Stable, amorphous potassium peroxystannate nanoparticles of controlled average size—in the range 10–100 nm—and of controlled hydrogen peroxide content—in the range of 19–30 wt%—were synthesized by hydrogen peroxide induced polymerization in water–potassium hexahydroxostannate solutions. The sol phase and the precipitate were characterized by vibrational spectroscopies, 119Sn NMR, XPS and XRD using crystalline K2Sn(OH)6 and K2Sn(OOH)6 reference materials. This is the first study to show that peroxocoordination induces polymerization of a main group element. 119Sn NMR studies show that peroxotin coordination and polymerization took place already in the hydrogen peroxide–water phase. The high abundance of peroxotin bonds revealed by 119Sn MAS NMR, vibrational spectroscopy, and XPS suggests that the particles are predominantly made of peroxo bridged tin networks. Although the particles are highly stable in the dry phase as well as in alcohol solutions and do not lose hydrogen peroxide upon storage, they release their stored hydrogen peroxide content by exposure to water.

Received: June 2, 2015; Accepted: March 5, 2016; Published: April 6, 2016, We describe a new species of gundi (Rodentia: Ctenodactylidae: Ctenodactylinae), Sayimys negevensis, on the basis of cheek teeth from the Early Miocene of the Rotem Basin, southern Israel. The Rotem ctenodactylid differs from all known ctenodactylid species, including Sayimys intermedius, which was first described from the Middle Miocene of Saudi Arabia. Instead, it most resembles Sayimys baskini from the Early Miocene of Pakistan in characters of the m1-2 (e.g., the mesoflexid shorter than the metaflexid, the obliquely orientated hypolophid, and the presence of a strong posterolabial ledge) and the upper molars (e.g., the paraflexus that is longer than the metaflexus). However, morphological (e.g., presence of a well-developed paraflexus on unworn upper molars) and dimensional (regarding, in particular, the DP4 and M1 or M2) differences between the Rotem gundi and Sayimys baskini distinguish them and testify to the novelty and endemicity of the former. In its dental morphology, Sayimys negevensis sp. nov. shows a combination of both the ultimate apparition of key-characters and incipient features that would be maintained and strengthened in latter ctenodactylines. Thus, it is a pivotal species that bridges the gap between an array of primitive ctenodactylines and the most derived, Early Miocene and later, gundis., The sojourn in Berlin was funded by the Alexander von Humboldt Foundation through sponsorship of renewed research stay in Germany, whereas that in Paris was funded by the SYNTHESYS Project (http://www.synthesys.info/), which is financed by the European Community Research Infrastructure Action under the FP7 “Capacities” Program., RLA is supported by the European Union via a Marie Curie fellowship (PIEF-GA-2013-623352).

Low concentration, as low as 0.4 wt.% graphene oxide organogels is reported for different organic solvents. The gelation of organic solvents at exceedingly low concentrations opens the door for the implementation of graphene oxides based electrolytes in various electrochemical applications. Here we demonstrate the use of acetonitrile–graphene oxide (GO) gel containing iodide/triiodide as a quasi-solid electrolyte for dye sensitized solar cells (DSCs). Electrochemical impedance studies reveal that the mass transfer barrier is not adversely affected by the presence of the minute amount of GO gel former. The achieved energy conversion efficiency (η) for the device without GO and with 1% GO gel electrolytes is 6.9% and 7.5% respectively under one sun illumination. Keywords: Graphene oxide, Organogel, Dye-sensitized solar cell, Quasi-solid state electrolyte

The purpose of this study was to compare the efficacy of three irrigation techniques for smear-layer removal with 17% EDTA.Cleaning and shaping the root canal system during endodontic treatment produces a smear layer and hard tissue debris. Three irrigation techniques were tested for solution infiltration of this layer: positive-pressure irrigation, passive ultrasonic irrigation, and laser-activated irrigation.Sixty extracted teeth were divided into six equal groups; 17% EDTA was used for 60 sec irrigation of five of the groups. The groups were as follows: Group 1, treated only with ProTaper™ F3 Ni-Ti files; Group 2, positive-pressure irrigation, with a syringe; Group 3, passive ultrasonic irrigation, inserted 1 mm short of the working length; Group 4, passive ultrasonic irrigation, inserted in the upper coronal third of the root; Group 5, Er:YAG laser-activated irrigation, inserted 1 mm short of the working length; and Group 6, Er:YAG laser-activated irrigation, inserted in the upper coronal third of the root.Scanning electron microscopy showed that the smear layer is removed most efficiently using laser-activated irrigation at low energy with 17% EDTA, inserted either at the working length or only in the coronal upper third of the root. Amounts of Ca, P, and O were not significantly different on all treated dentin surfaces.Smear-layer removal was most effective when the root canals were irrigated using Er:YAG laser at low energy with 17% EDTA solution. Interestingly, removal of the smear layer along the entire canal was similar when the laser was inserted in the upper coronal third and at 1 mm short of the working length of the root canal. This effect was not observed with the ultrasonic and positive-pressure techniques.

Nickel–manganese oxides with variable Ni : Mn ratios, synthesised from heterobimetallic single-source precursors, turned out to be efficient water oxidation catalysts. They were subjected to oxidant-driven, photo- and electro-catalytic water oxidation showing superior activity and remarkable stability. In addition, a structure–activity relation could be established.

Alkali ternary lead halides have been studied intensively in the past few years, with great interest focussed on perovskite materials. In this paper we report on novel rubidium lead chloride nanocrystals (NCs) with the formula Rb6Pb5Cl16, which adopt a tetragonal symmetry. The NCs were characterized and found to be active in the UV region, with a band-gap of ~4.05 eV. The roles of the ligands, oleic acid and oleylamine, were investigated and found to strongly affect the morphology and composition of the NCs, through the stabilization of the facilitated crystallization of the ionic precursors. The effective masses were observed by density functional theory (DFT) calculations, using the dielectric function, and the the Bohr exciton radius and exciton binding energy of the NCs were estimated. Moreover, the results were supported by the DFT calculations of the electronic properties and atomic structure.

Objective: The purpose of this study was to evaluate mineral content and surface morphology of root canals coated with Enterococcus faecalis biofilm after treatment with several endodontic irrigation solutions, with and without Er:YAG laser-activated irrigation (LAI).LAI has been introduced as a powerful method for root canal irrigation resulting in smear-layer removal from the root canal wall.Distal and palatal roots from 60 freshly extracted human molars were used in this study. The coronal of each tooth was removed. Roots were split longitudinally and placed in an ultrasonic bath to remove the smear layer, creating conditions for the formation of E. faecalis biofilm. After incubation, the two halves were reassembled in impression material to simulate clinical conditions. Specimens were divided into two main groups: roots rinsed with irrigation solutions and roots subjected to laser irradiation combined with irrigation solutions. Solutions tested were 2% chlorhexidine and 17% ethylenediaminetetraacetic acid (EDTA) and saline.Surface morphology: 17% EDTA irrigant solution combined with Er:YAG laser showed the best results for removing bacteria from the root canal walls. Chemical analysis: all samples treated with combined laser irradiation and irrigation solution had low surface levels of Ca compared with samples treated with irrigation alone. The Ca/P ratio was highest in the laser-EDTA group. Overall, mineral changes caused by laser with irrigation solutions were minimal, and statistically nonsignificant.In vitro irrigation solutions, combined with Er:YAG laser irradiation, were effective in removing E. faecalis biofilm from root canal walls. Irrigation solutions without laser irradiation were less effective, leaving a layer of biofilm on the dentin surface.

Many intriguing aspects of molecular electronics are attributed to organic-inorganic interactions, yet charge transfer through such junctions still requires fundamental study. Recently, there is a growing interest in anchoring groups, which considered dominating the charge transport. With this respect, we choose to investigate self-assembly of disilane molecules sandwiched between gold surface and gold nanoparticles. These assemblies are found to exhibit covalent bonds not only between the anchoring Si groups and the gold surfaces but also in plane crosslinks that increase the monolayer stability. Finally, using scanning tunneling spectroscopy we demonstrate that the disilane molecules provide strong electrical coupling between the Au nanoparticles and a superconductor substrate.

The essence of this study is to apply the Langmuir-Blodgett (LB) technique for assembling asymmetric membranes. Accordingly, Langmuir films of a (further) polymerizable polymer, 1,2-polybutadiene (1,2-pbd), were studied and transferred onto different solid supports, such as gold, indium tin oxide (ITO), and silicon. The layers were characterized both at the air/water interface as well as on different substrates using numerous methods including cyclic voltammetry, impedance spectroscopy, spectroscopic ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, and reflection-absorption Fourier transform infrared spectroscopy. The Langmuir films were stable at the air-water interface as long as they were not exposed to UV irradiation. The LB films formed disorganized layers, which gradually blocked the permeation of different species with increasing the number of deposited layers. The thickness was ca. 4-7 Å per layer. Irradiating the Langmuir films caused their cross-linking at the air-water interface. Furthermore, we took advantage of the reactivity of the double bond of the LB films on the solid supports and graft polymerized acrylic acid on top of the 1,2-pbd layers. This approach is the basis of the formation of an asymmetric membrane that requires different porosity on both of its sides.

(1) To determine the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and acidulated phosphate fluoride (APF) on S. mutans viability, (2) to observe their effects on biofilm structure, and (3) to examine the element content of the hydroxyapatite (HA) surfaces after exposure to CPP-ACP and APF.HA discs were coated with: CPP-ACP (GC Tooth-Mousse), APF, CPP-ACP+APF (1/1). Uncoated HA discs were used as control. Following application of the materials, the discs were immersed in human saliva and incubated with S. mutans ATCC (27315) for 24 hours. Growth of bacteria on the discs was evaluated by microbial culturing methods. The structure of the biofilm was examined with confocal laser scanning microscope (CLSM). The change in element content of HA surfaces (without biofilm) was evaluated with energy-dispersive x-ray spectroscopy (EDS). The values were statistically analyzed using Kruskal-Wallis and Dunn's test.The total number of bacteria of APF and CPP-ACP+APF applied groups were found significantly lower than the control group (P0.05). All specimens showed similar microbial colonization structure. No statistically significant differences were observed in O, F, Na, P, Ca content on HA surfaces after exposure to the tested agents, although fluoride concentration of the APF treated HA surfaces were increased compared to CPP-ACP, CPP-ACP +APF.

Drug-eluting stents (DESs) have been associated with adverse clinical effects. Moreover, recent publications have shown that the coating of DESs suffers from defects. The purpose of this contribution is to examine a three-step process for surface modification as a means of improving the durability of DESs. In the first step, 4-(2-bromoethyl)benzenediazonium tetrafluoroborate was electrografted onto a stainless steel (SS) stent. X-ray photoelectron spectroscopy (XPS) of the modified stent confirmed the formation of the organic layer. In the second step, methyl methacrylate was polymerized onto the grafted surface by atom-transfer radical polymerization. XPS, electrochemical impedance spectroscopy, and contact-angle measurements were used to characterize the polymer brushes. The last step involved spray-coating of the stent with a drug-in-polymer matrix [poly(n-butyl methacrylate)/poly(ethylene-co-vinyl acetate) + paclitaxel]. Scanning electron microscopy confirmed the considerably improved durability of the drug-in-polymer matrix. Bare controls showed greater cracking and delamination of the coating than did the two-step modified stents after incubation under physiological (37 degrees C) and accelerated (60 degrees C) conditions. Finally, paclitaxel controlled release from the modified SS DESs was moderate compared with that of nontreated samples. In conclusion, the proposed method significantly improves the durability of drug-in-polymer matrixes on a SS DESs.

The Langmuir-Blodgett (LB) method was used to deposit multilayers of polyaniline (PANI)- and mercaptoethanesulfonate (MES)-stabilized Au nanoparticles. The electrostatic interaction between the negatively charged nanoparticles in the subphase and the positively charged PANI at the air-water interface assisted the deposition of the nanocomposite film onto a solid support. These PANI/Au-NPs films were characterized using cyclic voltammetry, copper under potential deposition, scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. We found that the nanocomposite layers were uniform and reproducible. The density of Au-NPs in the monolayer depended on the acidity of the subphase as well as on the nanoparticles concentration. Moreover, the Au-NPs extrude above the PANI and therefore could be used as nanoelectrodes for the underpotential deposition (UPD) of copper.

A methodology for online preconcentration of analytes and their subsequent electrochemically induced delivery to an online electrospray mass spectrometer is introduced. The approach is based on electrodeposition of an active metallic layer, silver deposit in this particular case, subsequent specific accumulation of the target analyte by electrochemical or chemical means onto the active layer, and finally oxidative electrostripping of the conductive layer along with the supported analyte to an online mass spectrometer. We demonstrate the new concept by selective electrochemical deposition of homocysteine and other organothiols directly on the working electrode of a miniature flow cell. The same approach was extended to the conjugation of the target analyte (avidin as a test case) to a thiolated ligand (biotin in this case) that was electrodeposited on the silver coated surface. Electrostripping of the silver dissolves the target species and allows their delivery to an online ESI-MS. Furthermore, the dissolved silver ions promote ionization, and its characteristic isotopic pattern assists in the identification of the target analyte.

This review provides an overview of some exciting, new as well as somewhat older, directions in sol-gel electrochemical applications of silicates and composite silicate electrodes. Rather than provide an exhaustive account of all the many papers that have been published on sol-gel electrochemistry and composite sol-gel electrodes, we prefer to illustrate the versatility of sol-gel chemistry by a few select examples which on the one hand illustrate the power entailed in sol-gel technology for electrochemical applications, and on the other hand point to hot electrochemical fields in which more research is due and exciting developments are to be expected. We start this review with a brief historical perspective. The inorganic sol-gel and silicone electrochemistry fields are both rather old though never extensively dealt with particularly when it comes to sensing applications. In contrast, the sol-gel electrochemistry of inorganic-organic hybrids is a relatively young field whose importance was recognized only in the last 30 years, and despite, or maybe even owing to the late recognition it is being very extensively studied nowadays. The use of composite electrodes for sensing and other applications is emphasized in this review, and the fast evolving electrodriven deposition techniques are reviewed.

A photoisomerizable thiolated nitrospiropyran SP, (1a), monolayer is assembled on a Au electrode by the primary deposition of thiolated nitromerocyanine isomer 1b as a monolayer on the electrode, followed by the irradiation of the surface with visible light, lambda475 nm. The surface coverage of nitrospiropyran units (1a) on the electrode is 2 x 10-10 mole cm-2. Irradiation of the electrode with UV light, 320 nmlambda360 nm, results in the nitromerocyanine, MR, monolayer on the electrode that binds Ag+ ions to the phenolate units. The Ag+ ions associated with the MR monolayer undergo cyclic reduction to surface-confined Ag0 nanoclusters, and reoxidation and dissolution of the Ag0 nanoclusters to Ag+ ions associated with the monolayer are demonstrated. The electron-transfer rate constants for the reduction of Ag+ to Ag0 and for the dissolution of Ag0 were determined by chronoamperometry and correspond to ketred = 12.7 s-1 and ketox = 10.5 s-1, respectively. The nanoclustering rate was characterized by surface plasmon resonance measurements, and it proceeds on a time scale of 10 min. The size of the Ag0 nanoclusters is in the range of 2 to 20 nm. The electrochemically induced reduction of the MR-Ag+ monolayer to the MR-Ag0 surface and the reoxidation of the MR-Ag0 surface control the hydrophilic-hydrophobic properties of the surface. The advancing contact angle of the MR-Ag0-functionalized surface is 59 degrees , and the contact angle of the MR-Ag+-monolayer-functionalized surface is 74 degrees . Photoisomerization of the Ag0-MR surface to the Ag0-SP state, followed by the oxidation of the Ag0 nanoclusters, results in the dissolution of the Ag+ ions into the electrolyte solution.

We describe a new, simple and low-temperature method for ultra-thin coating of graphene oxide (GO) by peroxostannate, tin oxide or a mixture of tin and tin oxide crystallites by different treatments. The technique is environmentally friendly and does not require complicated infrastructure, an autoclave or a microwave. The supported peroxostannate phase is partially converted after drying to crystalline tin oxide with average, 2.5 nm cassiterite crystals. Mild heat treatment yielded full coverage of the reduced graphene oxide by crystalline tin oxide. Extensive heat treatment in vacuum at >500 °C yielded a mixture of elemental tin and cassiterite tin oxide nanoparticles supported on reduced graphene oxide (rGO). The usefulness of the new approach was demonstrated by the preparation of two types of lithium ion anodes: tin oxide-rGO and a mixture of tin oxide and tin coated rGO composites (SnO(2)-Sn-rGO). The electrodes exhibited stable charge/discharge cyclability and high charging capacity due to the intimate contact between the conductive graphene and the very small tin oxide crystallites. The charging/discharging capacity of the anodes exceeded the theoretical capacity predicted based on tin lithiation. The tin oxide coated rGO exhibited higher charging capacity but somewhat lower stability upon extended charge/discharge cycling compared to SnO(2)-Sn-rGO.

Halogen complexes of ruthenium cyclopentadienyl [CpRu(PTA) 2 X]; [CpRu(PTA)(PPh 3 )X]; [CpRu(PPh 3 ) 2 Cl], and [CpRu(mPTA)(PPh 3 )X] + (Cp = C 5 H 5 ; PTA = l,3,5-triaza-7-phosphaadamantane; mPTA + = [1-methyl-1,3,5-triaza-7-phosphaadamantane] + ; X = Cl - , I - ) were investigated by electrospray mass spectrometry (ESI-MS), in flow-cell cyclic voltammetry, by microelectrodes, and by combined online electrochemistry and electrospray mass spectrometry (EC/ESI-MS) in dimethyl formamide solution. Coordination changes and the structures of the initial compounds and the products of the electro-oxidation of the Ru(II) complexes were traced by in situ EC/MS n experiments which revealed their fragmentation pathways. ESI-MS collision-induced dissociation fragmentations of the initial reactants and the oxidation products were explained by soft acid-hard base considerations taking into account the different nature of Ru(II)-Ru(IV) centers. The electrochemical studies show that it is possible to tune the formal potentials for the oxidation of [CpRuL 2 X] complexes by over 300 mV by proper selection of the ligands. The increase of the redox potential by the different ligands follows the order PTA < PPh 3 < mPTA + . We demonstrate a similarity between the propensity of the ligand to fragment out in the gas phase and its relationship to the formal potential of the complex.