Cathodic stripping voltammetry of peptide complexes

Small peptides containing the histidine residue are considered as models of the metal binding site of bioactive peptides and proteins. The present study has been concerned with the cathodic stripping voltammetry of the copper complexes of imidazole (the parent molecule), and several histidine containing peptides; glycylglycyl-L-histidine (GGH), glycyl-L-histidylglycine (GHG), L-histidylglycine (HG), glycyl-L-histidine (GH), Carnosine (Car) and thyrotropine releasing factor(TRF). Accumulation and reduction mechanisms were further studied by cyclic voltammetry, and indirect cathodic stripping voltammetric method of determining these peptides has been developed. [Continues.

XPS characterization of Bi and Mn collected on atom-trapping silica for AAS

The chemical state of analyte species collected on a water-cooled silica tube during atom-trapping atomic absorption spectrometric determination is investigated with the use of X-ray photoelectron spectroscopy (XPS) for Bi and Mn. Analysis of the Bi 4f(7/2) peak reveals that the chemical state of Bi is +3 during initial trapping (before the atomization stage), but an additional 0-valence state of Bi is also observed after the atomization stage. With the use of the measured Mn 2p(3/2) binding energy together with the observed 3s multiplet splitting, the chemical state of Mn is determined as +2 in all stages. Together with our previous determination of 0 valence for Au, it is now postulated that the stability of certain valence states of the three elements (Au, Bi, and Mn) on the silica matrix can be correlated to their electrochemical reduction potentials

Self similar Barkhausen noise in magnetic domain wall motion

A model for domain wall motion in ferromagnets is analyzed. Long-range magnetic dipolar interactions are shown to give rise to self-similar dynamics when the external magnetic field is increased adiabatically. The power spectrum of the resultant Barkhausen noise is of the form $1/\omega^\alpha$, where $\alpha\approx 1.5$ can be estimated from the critical exponents for interface depinning in random media.Comment: 7 pages, RevTex. To appear in Phys. Rev. Let

Isolation, genotyping and antimicrobial susceptibility of pathogenic Escherichia coli serotypes in ready to eat foods

NO ABSTRACT AVAILABLEIn this study, pathogenic Escherichia coli serotypes (E. coli O157:H7, O26, O111) and their molecular proximity and antimicrobial susceptibility were investigated in RTE foods. A total of 240 samples; consist of 105 stuffed mussel, 56 meatless cig kofte, 54 Russian salad, 25 cheese halva, were analyzed. The conventional culture and serotyping methods for determination of the organisms were performed and further confirmation by PCR was carried out. Confirmed E. coli O157 isolates were genotyped by the enterobacterial repetitive intergenic consensus(ERIC)-PCR. Antibacterial susceptibility testing of the isolates was performed by disc diffusion method. E. coli was detected in 7 (2.9 %) of 240 samples, including 3 (5.5%) Russian salad, 3 (2.8%) stuffed mussel, 1 (4 %) cheese halva. Two isolates from Russian salad, 1 from stuffed mussel and 1 from cheese halva were identified as E. coli O157 . In addition, stuffed mussel isolate was found to carry stx1 ve hlyA genes whereas one Russian salad isolate carried the stx1 gene. E. coli isolates were found to be resistant to amoxycillin/clavulonic acid, gentamicin and ciprofloxacin, at the rate of 29%, 14% and 29 %, respectively. Only one (14 %) isolate from stuffed mussel was classified as multidrug resistant to three antimicrobials. Furthermore, the isolates, related to O157 and O157:H7, presented different ribotypes in this study. The results provide useful data for the development of public health policy concerning the potential presence of pathogenic antimicrobial resistant E. coli serotypes in RTE foods. Strict surveillance of RTE foods at retail points for emerging pathogens, their antimicrobial resistance patterns and the potential likelihood of cross-contamination is required

Isolation, genotyping and antimicrobial susceptibility of pathogenic Escherichia coli serotypes in ready to eat foods

NO ABSTRACT AVAILABLEIn this study, pathogenic Escherichia coli serotypes (E. coli O157:H7, O26, O111) and their molecular proximity and antimicrobial susceptibility were investigated in RTE foods. A total of 240 samples; consist of 105 stuffed mussel, 56 meatless cig kofte, 54 Russian salad, 25 cheese halva, were analyzed. The conventional culture and serotyping methods for determination of the organisms were performed and further confirmation by PCR was carried out. Confirmed E. coli O157 isolates were genotyped by the enterobacterial repetitive intergenic consensus(ERIC)-PCR. Antibacterial susceptibility testing of the isolates was performed by disc diffusion method. E. coli was detected in 7 (2.9 %) of 240 samples, including 3 (5.5%) Russian salad, 3 (2.8%) stuffed mussel, 1 (4 %) cheese halva. Two isolates from Russian salad, 1 from stuffed mussel and 1 from cheese halva were identified as E. coli O157 . In addition, stuffed mussel isolate was found to carry stx1 ve hlyA genes whereas one Russian salad isolate carried the stx1 gene. E. coli isolates were found to be resistant to amoxycillin/clavulonic acid, gentamicin and ciprofloxacin, at the rate of 29%, 14% and 29 %, respectively. Only one (14 %) isolate from stuffed mussel was classified as multidrug resistant to three antimicrobials. Furthermore, the isolates, related to O157 and O157:H7, presented different ribotypes in this study. The results provide useful data for the development of public health policy concerning the potential presence of pathogenic antimicrobial resistant E. coli serotypes in RTE foods. Strict surveillance of RTE foods at retail points for emerging pathogens, their antimicrobial resistance patterns and the potential likelihood of cross-contamination is required

XPS characterization of Bi and Mn collected on atom-trapping silica for AAS

The chemical state of analyte species collected on a water-cooled silica tube during atom-trapping atomic absorption spectrometric determination is investigated with the use of X-ray photoelectron spectroscopy (XPS) for Bi and Mn. Analysis of the Bi 4f7/2 peak reveals that the chemical state of Bi is +3 during initial trapping (before the atomization stage), but an additional 0-valence state of Bi is also observed after the atomization stage. With the use of the measured Mn 2p3/2 binding energy together with the observed 3s multiplet splitting, the chemical state of Mn is determined as +2 in all stages. Together with our previous determination of 0 valence for Au, it is now postulated that the stability of certain valence states of the three elements (Au, Bi, and Mn) on the silica matrix can be correlated to their electrochemical reduction potentials

On dual Rickart modules and weak dual Rickart modules

Let R be a ring. A right R-module M is called d-Rickart if for every endomorphism φ of M, φ(M) is a direct summand of M and it is called wd-Rickart if for every nonzero endomorphism φ of M, φ(M) contains a nonzero direct summand of M. We begin with some basic properties of (w)d-Rickart modules. Then we study direct sums of (w)d-Rickart modules and the class of rings for which every finitely generated module is (w)d-Rickart. We conclude by some structure results

On the role of laser-induced microstructures in influencing the surface energy of magnesia partially stabilized zirconia bioceramic

Surface energy must in some way be connected to surface chemistry and is therefore an important determinant of a biomaterial’s functions. This work elucidates the basic phenomena and wetting mechanisms associated for a widely used bioinert ceramic, magnesia partially stabilized zirconia (MgO-PSZ) following CO2 laser treatment. Contact angles for a set of test liquids were used to measure the wettability characteristics and to reduce the surface energy of the MgO-PSZ before and after CO2 laser treatment. CO2 laser treatment of the MgO-PSZ surface was seen to effect an improvement in the material’s wettability characteristics. Furthermore, it was found that the extent of wettability modi®cation was closely related to the microstructure induced by CO2 laser radiation on the surface of the MgO-PSZ

Finite Size Correction In A Disordered System - A New Divergence

We show that the amplitude of the finite size correction term for the $n$th moment of the partition function, for randomly interacting directed polymers, diverges (on the high temperature side) as $(n_c - n)^{-r}$, as a critical moment $n_c$ is approached. The exponent $r$ is independent of temperature but does depend on the effective dimensionality. There is no such divergence on the low temperature side ($n>n_c)$.Comment: 8 pages, Revtex, 5 figures. For figs, send mail to [email protected]