Detection and identification of mycobacteria in formalin-fixed, paraffin-embedded tissues by nested PCR and restriction enzyme analysis

A novel assay based on a nested PCR and restriction enzyme analysis of the PCR products was developed for the rapid detection and identification of Mycobacterium bovis and M. avium-M. intracellulare species in formalin-fixed, paraffin-embedded tissue (PET) specimens. On the basis of the nucleotide sequence data obtained in the present study, general nested primers were constructed to amplify a 424-bp segment of the gene encoding the 65-kDa surface antigen of mycobacteria. The nested PCR assay proved to be highly sensitive, since as little as 5 to 10 fg of extracted mycobacterial DNA was detected. The safety of the assay as a routine method for the diagnosis of M. bovis and M. avium-M. intracellulare in PET specimens was provided by taking various precautions. In order to prevent false positivity, specific tools and procedures were applied. To detect false-negative results and assess the efficiency of the PCR, an internal standard molecule of amplification was constructed. The digestion of the amplicons with the restriction endonuclease Sau96-I allowed the identification of M. bovis and M. avium-M. intracellulare in a large number of clinical specimens. The present results indicate that PCR combined with an internal control of amplification and restriction enzyme analysis of the amplicons provides a rapid, sensitive, and reliable method for routine diagnostic laboratories to detect and identify M. bovis and M. avium-M. intracellulare in PET specimens.     

A 7 year long measurement period investigating the correlation of corrosion,deposit and fuel in a biomass fired circulated fluidized bed boiler

The present investigation involves a unique, 7 year (2001–2007) long study of corrosion and deposits on superheater tubes in a biomass fired circulated fluidized bed boiler. These measurements are correlated against the different fuels used over this period. In the earlier years, the boiler was run with a mixture of different biomass fuels and peat. In later years, recycled wood was introduced into the fuel mix. The deposit growth rate approximately doubled when the recycled wood content of the fuel was increased to 10–20%. Small amounts of chlorine and zinc were found both in the recycled wood and in the deposit layer. These elements together with alkali metals from the biomass, have the potential to form sticky compounds that increase the deposit growth rate. The corrosion rate of the superheater tubes varied over the study period. A number of possible explanations for this phenomenon are discussed.     

Deposition of functionalized single wall carbon nanotubes through matrix assisted pulsed laser evaporation

Single-wall carbon nanotubes (SWCNTs) functionalized with oxygen-containing groups were deposited onto glass substrates by matrix assisted pulsed laser evaporation (MAPLE). The experiments were performed by subjecting ultraviolet laser pulses (KrF¹ excimer laser, 248 nm wavelength) to frozen SWCNT-toluene targets placed in a parallel plane a few cm in front of the substrate. The morphology, structure, and chemical composition of the deposited materials were studied through atomic force microscopy, high resolution transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The influence of the laser fluence on the material structure was investigated. The results indicate that the functionalized SWCNTs can be transferred by MAPLE at low laser fluences without the alteration of the structure of the initial material used as targets in MAPLE experiments. An increase of the fluence leads to the decomposition of the functional groups, mainly carboxylic acid groups, without degradation of the SWCNT structure whereas, at the highest fluences, the amorphization and even coalescence of the carbon nanotubes takes place.     

Numerical and Experimental Study on Fluid Dynamic Features of Combined Gas and Electromagnetic Stirring in Ladle Furnace

Basic fluid dynamic features of combined electromagnetic stirring, EMS, and gas stirring (EMGAS) have been studied in the present work. A transient and turbulent multiphase numerical flow model was built. Simulations of a real size ladle furnace were conducted for 7 cases, operating with and without combined stirring and varying the argon gas inlet plug position. The results of these simulations are compared considering melt velocity, melt turbulence, melt/slag‐interface turbulence and dispersion of gas bubbles. An experimental water model was also built to simulate the effects of combined stirring. The water model was numerically simulated and visual comparison of the gas plume shape and flow pattern in the numerical and in the experimental model was also done for 3 flow situations. The results show that EMGAS has a strong flexibility regarding the flow velocity, gas plume, stirring energy, mixing time, slag layer, etc.     

The influence of alkaline treatment on the chemical composition and adsorption-structural characteristics of mineral nanoporous sorbent M<Subscript>45</Subscript>K<Subscript>20</Subscript>

The chemical and adsorption-structural properties of natural nanoporous mineral sorbent M₄₅C₂₀ having two main components (clay-montmorillonite and zeolite-clinoptilolite) and treated with 2M NaOH solution are investigated. It is ascertained based on the results of chemical analysis, X-ray diffraction, electron microscopy, and IR spectrometry that alkali treatment results in modification of the chemical composition and structure of the mineral sorbent M₄₅C₂₀ and significantly improves its adsorption properties.     

The Requirements for the Calibration Conditions in Large-Aperture Fizeau Interferometers

The problems that arise during the calibration of the reference plates of large-aperture interferometers are discussed and the methods for solving them are presented. It is shown that the repeatability of shapes of the reference plates after their rearrangements can be provided by selecting the mechanism of their fixing in place. It is demonstrated that the temperature deformations of the reference-plate surfaces can be determined from a numerical model. These measures have made it possible to calibrate the reference plates of the 630-mm interferometer with an accuracy of λ/1000 RMS (λ = 632.8 nm).     

Determination of the refractive index and thickness of holographic silver halide materials by use of polarized reflectances

A method to determine the refractive index and thickness of silver halide emulsions used in holography is presented. The emulsions are in the form of a layer of film deposited on a thick glass plate. The experimental reflectances of p-polarized light are measured as a function of the incident angles, and the values of refractive index, thickness, and extinction coefficient of the emulsion are obtained by using the theoretical equation for reflectance. As examples, five commercial holographic silver halide emulsions are analyzed. The procedure to obtain the measurements and the numerical analysis of the experimental data are simple, and agreement of the calculated reflectances, by use of the thickness and refractive index obtained, with the measured reflectances is satisfactory.     

Storage of quantum coherences as phase-labelled local polarization in solid-state nuclear magnetic resonance

Nuclear spins are promising candidates for quantum information processing because their good isolation from the environment precludes the rapid loss of quantum coherence. Many strategies have been developed to further extend their decoherence times. Some of them make use of decoupling techniques based on the Carr-Purcell and Carr-Purcell-Meiboom-Gill pulse sequences. In many cases, when applied to inhomogeneous samples, they yield a magnetization decay much slower than that of the Hahn echo. However, we have proved that these decays cannot be associated with longer decoherence times, as coherences remain frozen. They result from coherences recovered after their storage as local polarization and thus they can be used as memories. We show here how this freezing of the coherent state, which can subsequently be recovered after times longer than the natural decoherence time of the system, can be generated in a controlled way with the use of field gradients. A similar behaviour of homogeneous samples in inhomogeneous fields is demonstrated. It is emphasized that the effects of inhomogeneities in solid-state nuclear magnetic resonance, independently of their origin, should not be disregarded, as they play a crucial role in multipulse sequences.