Note: High sensitivity pulsed electron spin resonance spectroscopy with induction detection

Commercial electron spin resonance spectroscopy and imaging systems make use of the so-called "induction" or "Faraday" detection, which is based on a radio frequency coil or a microwave resonator. The sensitivity of induction detection does not exceed ~3 × 10(8) spins/√Hz. Here we show that through the use of a new type of surface loop-gap microresonators (inner size of 20 μm), operating at cryogenic temperatures at a field of 0.5 T, one can improve upon this sensitivity barrier by more than 2 orders of magnitude and reach spin sensitivities of ~1.5 × 10(6) spins/√Hz or ~2.5 × 10(4) spins for 1 h.     

Ultrasound‐assisted coating of nylon 6,6 with silver nanoparticles and its antibacterial activity

A silver/nylon 6,6 nanocomposite containing 1 wt % metallic silver has been produced from an aqueous solution of silver nitrate in the presence of ammonia and ethylene glycol by an ultrasound‐assisted reduction method. The structure and properties of nylon 6,6 coated with silver have been characterized with X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, energy‐dispersive X‐ray, X‐ray photoelectron spectroscopy, Raman spectroscopy, and diffused reflection spectroscopy measurements. The nanocrystals of pure silver, 50–100 nm in size, are finely dispersed on the polymer surface without damaging the nylon 6,6 structure. This silver–nylon nanocomposite is stable to many washing cycles and thus can be used as a master batch for the production of nylon yarn by melting and spinning processes. The fabric knitted from this yarn has shown excellent antimicrobial properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1423–1430, 2007     

Deposition of Gold Particles on Mesoporous Catalyst Supports by Sonochemical Method, and their Catalytic Performance for CO Oxidation

Supported gold catalysts on the mesoporous (MSP) metal oxides were prepared by a one-step, ultrasound-assisted reduction method, and characterized by XRD, HRTEM, EDX, BET, and XPS analysis. Their catalytic activities were examined in the oxidation of CO. Compared to the Au/Fe₂O₃(MSP) catalyst, the Au/TiO₂(MSP) and Au/Fe₂O₃-TiO₂(MSP) catalysts exhibited higher catalytic activity in the oxidation of CO at low temperatures. The high catalytic activity of Au/TiO₂(MSP) was attributed to the metallic state of the gold nanoparticles, their small size (2–2.5 nm), and their high dispersion on the catalyst support.     

Electrochemical polymerization of xylene derivatives on carbon fiber

Electrochemically initiated polymerization on carbon fibers is an attractive process for combining fibers with a polymer matrix. An aromatic monomer, α,α′-para-xylene, was successfully polymerized on carbon fibers in a three-compartment electrolysis cell. A composite topreg with 40 volume percent of polymer was obtained. The polymer coating has a porous texture. The polymerization is rapid and efficient. Polymerization conditions and composite thermal properties are described.     

No Major Role for Binding by Salivary Proteins as a Defense Against Dietary Tannins in Mediterranean Goats

We investigated whether Mediterranean goats use salivary tannin-binding proteins to cope with tannin-rich forages by determining the affinity of salivary or parotid gland proteins for tannic acid or quebracho tannin. Mixed saliva, sampled from the oral cavity, or parotid gland contents were compared to the intermediate affinity protein bovine serum albumin with a competitive binding assay. Goats that consume tannin-rich browse (Damascus) and goats that tend to avoid tannins (Mamber) were sequentially fed high (Pistacia lentiscus L.), low (vetch hay), or zero (wheat hay) tannin forages. Affinity of salivary proteins for tannins did not differ between goat breeds and did not respond to presence or absence of tannins in the diet. Proteins in mixed saliva had slightly higher affinity for tannins than those in parotid saliva, but neither source contained proteins with higher affinity for tannins than bovine serum albumin. Similarly, 3 months of browsing in a tannin-rich environment had little effect on the affinity of salivary proteins for tannin in adult goats of either breed. We sampled mixed saliva from young kids before they consumed forage and after 3 months of foraging in a tannin-rich environment. Before foraging, the saliva of Mamber kids had higher affinity for tannic acid (but not quebracho tannin) than the saliva of Damascus kids, but there was no difference after 3 months of exposure to tannin-rich browse, and the affinity of the proteins was always similar to the affinity of bovine serum albumin. Our results suggest there is not a major role for salivary tannin-binding proteins in goats. Different tendencies of goat breeds to consume tannin-rich browse does not appear be related to differences in salivary tannin-binding proteins.     

High modulus thermoplastic segmented polyurethane/poly(L-lactide) blends as potential candidates for structural implantable drug delivery systems: I. Structure-properties relationship study

Structural polymers with a high modulus of elasticity have the necessary properties for drug eluting implants which are continuously subjected to long-term loading. The range of polymers that can be used for this purpose is severely limited by the demanding requirements, such as biocompatibility, specific mechanical properties and the capability to control the release rate of incorporated drugs. A new series of blend compositions was developed for these applications, based on a combination of a high modulus thermoplastic segmented polyurethane (TSPU) (shore D hardness) and poly(L-lactide) (PLLA). The microstructures and properties of these blends were characterized by DSC, tensile tester, FTIR, SEM, WAXD, transmitted light microscopy and elastic recovery testing. The two polymers were found to be immiscible, irrespective of the weight ratio between them, but still compatible, although the compatibility was reduced in blends with equal weight ratios or thereabouts. The dispersed phase in any case spontaneously organized into microspheres embedded within the continuous phase. PLLA could recrystallize as both the dispersed and the continuous phases. The ultimate mechanical properties and the elastic load-recovery of the blends were largely dependent on the ratio between the polymers. The ability of these blends to create self-assembled microspheres and the fact that they did not require a compatibilizer or plasticizer point to the potential of these systems to be used for structural implantable drug delivery systems.     

The fate of heavy metals in wastewater stabilization ponds

The distribution of toxic heavy metals was studied throughout the process of treatment of domestic wastewater by stabilization ponds. The concentrations and distribution of free and bound zinc, cadmium, lead and copper through the various stages of a treatment plant were analyzed by Anodic Stripping Voltammetry (ASV). Only a slight decrease in the total metals concentration was observed during the various stages of the wastewater treatment plant. However, the distribution among dissolved (free and chelated) and particulate fractions did change towards solubilization of most of the particulate fraction. Within the soluble fraction a significant decrease in the free cations occurred due to a proteinaceous chelating agent(s) released by the microbial population in the ponds. A similar phenomenon was found in simulated laboratory experiments which were carried out with a Chlorella strain isolated from the stabilization ponds.