Incidence of Yersinia enterocolitica in raw farm and market milk sample

Objectives: This study was applied to investigate the incidence of Yersinia enterocolitica in raw farm and market milk and studying the quality drawbacks which might happen in milk as a result of its existence.Design: Observation study.Samples: One hundred raw milk samples.Procedures: Fifty bulk tank milk (BTM), 25 individual milk & 25 market milk samples were collected from various dairy farms and supermarkets in Dakahlia Governorate, Egypt. The quality assessment of the samples began with evaluating the milk physical characteristics including color, odor, pH and the titratable acidity that reflected the hygienic quality of milk production on farm levels. Then the samples were directed for biochemical and microbiological examination with subsequent PCR approach.Results: The range of titratable acidity started from 0.11 – 0.20 % lactic acid with a mean value of 0.15 ± 0.004. While for microbiological examination of the samples by using the conventional methods of cultivation on (CIN) agar medium, 33 presumptive Yersinia isolates were recovered and intended for biochemical tests among which 5 out of these latter isolates were confirmed as Y. enterocolitica by applying PCR, through detecting the presence of 16srRNA gene. Also, this study evaluates not only the public health of consumers concerning the titratable acidity of the examined samples, but also the economic importance of these retailed samples in supermarkets; as Y. enterocolitica could be transmitted through the consumption of raw milk. Conclusion and Clinical Relevance: The Y. enterocolitica incidence was 29% in the examined raw farm and market milk samples

Laser gain calculations for soft X-ray and XUV radiation emitted from copper like ions by electron collisional pumping

Electron impact excitation rate coefficients, Level population densities and gain coefficients for six excited ions with Z = 51, 52, 53, 54, 55, 56 in the copper isoelectronic sequence have been calculated. The electron collisional excitation rate coefficients are calculated according to the analytical formulas of Vriens and Smeets. Fine structure energy levels, transition probabilities and oscillator strengths needed in the calculations have been calculated using Cowan atomic structure code with relativistic corrections for [Ar]3d10nl with n = 4-7 and l = 0-6. The level population densities are calculated by solving the coupled rate equations involving 30 levels. Positive gain coefficients of the possible emitted lines are obtained at three selected electron temperatures namely 1/4, 1/2 and 3/4 of the ionization energy. The present calculated data show promising values for the production of soft X-ray and XUV laser by collisional pumping for the transitions 5p-5s and 6d-5f with wavelengths between 108 Å and 571 Å. The values of the maximum gain coefficient are found to increase with atomic number and their order of magnitude ranges from102 cm-1 to 104 cm−1.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Site of action of hematoporphyrin (a photo-activated insecticide) in Culex pipiens larvae

The histopathological effect of hematoporphyrin on the mid-gut and the integument of the fourth larval instar of C. pipiens was studied using a transmission electron microscope. In this study C. pipiens larvae were treated with different concentration of hematoporphyrin. The concentration 5 × 10-4 M/L was found to produce 100% mortality after half-hour exposure to the 400 W/M2 artificial lights using a solar simulator. The ultrastructural examination showed that the normal lamellate cuticle was heavily affected, taking the shape of amorphous cuticular region. The endo- and exo-cuticle were not distinguishable. It was found that the epidermal cells underneath the cuticle were distorted. The mitochondria of these cells exhibited irregular shapes. The fat body underneath the integument could be detected with visible vacuolisation. Muscle cells revealed the degenerated sarcomeres with gaps and vacuoles. The Z discs have irregular shape and are distorted. Mid-gut cells appeared with cytoplasmic vacuoles. The Golgi body is fragmented into small bodies. The rough endoplasmic reticulum is broken-down into separate vascular structures. These cytopathological observations confirm the insecticidal efficiency of hematoporphyrin against C. pipiens larvae. KEY WORDS: histopathology, mid-gut, integument, insect larvae, TEM Egyptian Journal of Biology Vol.4 2002: 133-14