A survey of antibiotic resistance in Micrococcaceae isolated from Italian dry fermented sausages

The transfer of bacteria that are resistant to antimicrobial agents or resistance genes from animals to humans via the food chain is increasingly a problem. Therefore, it is important to determine the species and the numbers of bacteria involved in this phenomenon. For this purpose, 148 strains of microstaphylococci were isolated from three types of Italian dry fermented sausages. Eight of 148 strains belonged to the genera Kocuria and Micrococcus. The remaining 140 strains belonged to 11 different species of the genus Staphylococcus. The species most frequently isolated was Staphylococcus xylosus, followed by Staphylococcus saprophyticus and Staphylococcus aureus. Antibiotic resistance levels differed among the species and depended on the strain origin. Microstaphylococci were generally susceptible to beta-lactams, but 12 strains were resistant to methicillin, 8 were resistant to oxacillin, and 9 were resistant to penicillin G. No resistance was observed for aminoglicosides and cephalosporines. Many strains were resistant to sulfonamide, colistin suphate, tetracyclin, and bacitracin. Two strains of S. aureus, four strains of S. xylosus, and one strain of Staphylococcus sciuri were able to grow in the presence of 8 microg of vancomycin per g, but all strains were susceptible to teicoplanin. Twenty-two microstaphylococci were resistant to at least five of the tested antibiotics. The multiresistant strain S. aureus 899 was unaffected by eight antibiotics, including vancomycin and methicillin, indicating that a more prudent use of antibiotics in animal husbandry and better hygienic conditions during production should be encouraged because they can play a major role in reducing the incidence of such multiresistant microorganisms and the possible spread of the genetic elements of their resistance.     

The influence of extrinsic and intrinsic risk factors on the probability of sustaining an injury

This study was designed to quantify the relative contributions of extrinsic and intrinsic risk factors to the probability of an injury event. A case-control design was used with data collected from injured patients at an emergency department (n=797) and a community sample matched on area of residence and time of injury (n=797). Principal components analysis was used to develop scales for the measurement of 'intrinsic' risk taking tendencies that were slightly modified versions of previously published measures. Two principal components were identified: 'health risk taking' (HRT) and 'adventurous risk taking' (ART). Logistic regression analysis identified variables that significantly predicted membership of the group of injured cases. The main hypothesis was supported by the results: that 'extrinsic' factors such as location, activity, drug and alcohol use and the type of people present at the time of the injury were related to a greater risk of injury than 'intrinsic' variables (health and adventurous risk taking tendencies). The results suggest that injury research and prevention efforts should continue to focus on the identification and modification of situational risk factors for injury rather developing programs that focus on high-risk individuals. High-risk alcohol use, use of prescribed drugs and aspects of work and recreational environments were identified as warranting particular attention.     

High-resolution solid-state NMR studies on uniformly [13C,15N]-labeled ubiquitin

Understanding of the effects of intermolecular interactions, molecular dynamics, and sample preparation on high-resolution magic-angle spinning NMR data is currently limited. Using the example of a uniformly [13C,15N]-labeled sample of ubiquitin, we discuss solid-state NMR methods tailored to the construction of 3D molecular structure and study the influence of solid-phase protein preparation on solid-state NMR spectra. A comparative analysis of 13C', 13Calpha, and 13Cbeta resonance frequencies suggests that 13C chemical-shift variations are most likely to occur in protein regions that exhibit an enhanced degree of molecular mobility. Our results can be refined by additional solid-state NMR techniques and serve as a reference for ongoing efforts to characterize the structure and dynamics of (membrane) proteins, protein complexes, and other biomolecules by high-resolution solid-state NMR.     

The electrical properties of CuInSe2 thin films deposited onto CaF2 substrates

CuInSe₂ thin films were deposited onto (111)-oriented CaF₂ substrates by flash evaporation in the substrate temperature range T_s = 650–890 K. Epitaxial growth was found at T_s = 770–800 K; at lower and higher substrate temperatures the films were partly polycrystalline. Films produced at T_s ? 675 K showed n-type conductivity due to a donor with an ionization energy of 78 ± 5 meV ascribed to indium interstitials. At T_s ? 725 K the films exhibited p-type conductivity due to a shallow acceptor with an ionization energy characteristic of indium vacancies. The important role of the substrate material in establishing the electrical parameters of CuInSe₂ thin films is proved by a comparative study of thin films deposited onto GaAs and CaF₂ substrates.     

Numerical properties of integral equations in which the given boundary values and the sought solutions are defined on different curves

Solving boundary value problems in plane elastostatics with the aid of integral equations the boundary of the elastic body usually represents the domain of definition of the sought solution as well as of the given boundary values. However, it is also possible to define the solution and the boundary values on two spatially separated curves $\text{S}\text{?}$ and S. In this paper the numerical properties of both methods are investigated and compared and in particular the influence of the distance between $\text{S}\text{?}$ and S is estimated. For these purposes the eigenvalues and eigenfunctions of the operators in the integral equations are determined.     

Some methodological issues in semantic differential research.

A review of methodological research on the semantic differential (SD) shows that: (a) metric assumptions in SD scales are in some ways inaccurate but adequate for many applications; (b) biased errors may arise because of social desirability effects or scale-checking styles; (c) a substantial portion of variation in SD ratings is due to individual differences and temporal variations in responses; (d) basic dimensions of average response on SD scales are evaluation, potency, and activity, and no extensive proliferation of basic dimensions beyond these can be expected; (e) there are individual differences in the size and character of the semantic space; (f) the appearance of scale-concept interactions frequently is a methodological artifact which would not occur in adequately designed studies; and (g) the existence of real scale-concept interactions demands tailoring the SD to different stimulus domains, but these studies must be carried out with care. (58 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Porous electrodes supported on ion-exchange membranes as electrochemical detectors for supercritical fluid chromatography

A conveniently assembled electrochemical cell, exploiting a porous electrode supported on a moist perfluorinated ion-exchange polymer, is proposed for profitable electrochemical detection in supercritical fluid chromatography. It consists of a porous Pt working electrode, contacted by the mobile phase from the chromatographic column, which is chemically deposited onto one side of a Nafion membrane. The rear uncoated side of this membrane, acting as a solid polymer electrolyte, is contacted by an electrolyte solution (1 M NaCl) contained in an internal compartment equipped with a Pt counter electrode and a Ag/AgCl, Cl(-) 1 M reference electrode. Ferrocene, eluted with supercritical carbon dioxide through a Spherisorb column installed in a supercritical fluid chromatographic system, was used as electroactive prototype analyte to test the performance of this detector, which turned out to be quite better than that provided by a conventional on-line UV absorbance detector. The recorded peaks were characterized by both a good reproducibility (4.5%) and a linear dependence of their height and area, which extended over a wide concentration range ( approximately 3 orders of magnitude). Moreover, they were not interfered by possible solvent front, unlike peaks recorded by the UV detector. The detection limit, estimated for a signal-to-noise ratio of 3 (4.2 x 10(-11) mol), was lower by approximately 1 order of magnitude than that found for the UV detector. Finally, the long-term stability of this detector was satisfactory in that only a approximately 6% decrease in the current responses was observed after a rather long period (2 months) of continuous use.     

Biodegradation of propylene glycol and associated hydrodynamic effects in sand

At airports around the world, propylene glycol (PG) based fluids are used to de-ice aircraft for safe operation. PG removal was investigated in 15-cm deep saturated sand columns. Greater than 99% PG biodegradation was achieved for all flow rates and loading conditions tested, which decreased the hydraulic conductivity of the sand by 1-3 orders of magnitude until a steady-state minimum was reached. Under constant loading at 120 mg PG/d for 15-30 d, the hydraulic conductivity (K) decreased by 2-2.5 orders of magnitude when the average linear velocity of the water was 4.9-1.4 cm/h. Variable PG loading in recirculation tests resulted in slower conductivity declines and lower final steady-state conductivity than constant PG feeding. After significant sand plugging, endogenous periods of time without PG resulted in significant but partial recovery of the original conductivity. Biomass growth also increased the dispersivity of the sand.     

Fabrication, polarisation and wavelength insensitive optical switch/attenuator based on adiabatic mode multiplexer

Experimental results of an adiabatic mode multiplexer (AMM) based novel 2/spl times/2 optical switch/variable optical attenuator that consists of a symmetric Y-branch interferometer (mode converter) and adiabatic mode multiplexer/demultiplexer pair are presented. It is shown that both normally cross and bar designs have identical optical performance. Extinction ratio without thermal activation is wavelength independent. Over C-band the attenuation at -20 dB varies by less than 0.3 dB and polarisation dependent loss is less than 1 dB. It is proved that the mode converter plays a dominant role in polarisation state sensitivity at high attenuation values and can be optimised by varying interferometer arm length. Since an AMM-based switch does not require process optimisation steps it can be fabricated within a process optimised for other optical devices.