Inactivation by ionizing radiation of Salmonella enteritidis,Salmonella infantis,and Vibrio parahaemolyticus in oysters (Crassostrea brasiliana)

Irradiation is considered one of the most efficient technological processes for the reduction of microorganisms in food. It can be used to improve the safety of food products, and to extend their shelf lives. Oysters are considered one of the most important vehicles for pathogenic bacteria because of their feeding characteristics. The aim of this study was to evaluate the influence of a gamma radiation process on high levels of Salmonella Enteritidis, Salmonella Infantis, and Vibrio parahaemolyticus incorporated by oysters (Crassostrea brasiliana), as well as the effects of the process on the survival of the oysters and on their sensory attributes. The oysters were exposed to gamma radiation (60Co) in doses ranging from 0.5 to 3.0 kGy. A dose of 3.0 kGy was generally sufficient to reduce the level of Salmonella serotypes by 5 to 6 log10 units. A dose of 1.0 kGy was sufficient to produce a 6-log10 reduction in the level of V. parahaemolyticus. The highest irradiation dose did not kill the oysters or affect their sensory attributes. Hence, a dose of 3.0 kGy can be considered effective in inactivating Salmonella and V. parahaemolyticus in oysters without changing their odor, flavor, or appearance.     

Determination of peroxy radical-scavenging of lactic acid bacteria

Responses of lactic acid bacteria (LAB) to peroxy radicals generated via thermal (40 degrees C) decomposition of the diazocompound 2,2,-azo-bis (2-amidinopropane) dihydrochloride (ABAP), were studied. In general, LAB displayed survival curves with shoulders and tails indicative of 'multihit' killing by exposure to peroxy radicals. One strain, Lactococcus lactis subsp. lactis DIP15, producing a slope of 0.0105 in the kinetic analysis when exposed to 4 mM ABAP, exhibited a measurable antioxidant capacity. The other LAB failed to show any significant antioxidant capacity. The antioxidant capacity of strain DIP15 remained constant after cells have been heat-treated, suggesting that compounds bearing free radical scavenging capacity are rather stable.     

Moraxella (Branhamella) catarrhalis: its isolation in the respiratory secretions of adult patients

OBJECTIVE: We have designed a retrospective study in order to know the clinical significance of the isolation of Moraxella (Branhamella) catarrhalis (MC) in respiratory specimens of adult hospitalized patients. METHODS: We performed a Gram stain and culture on blood-agar, MacConkey media and quantitative culture in chocolate-agar to all respiratory samples. In patients with a clinical diagnosis of pneumonia BCYE-alpha was added. During 2 years (1992-1993) MC was isolated in respiratory specimens from 52 patients. We revised the clinical history of all these patients. RESULTS: MC was isolated in 60 respiratory specimens (sputum and/or tracheobronchial aspirates) from 52 patients. The Gram stain showed gram-negative cocci in 77% and gram-positive cocci in 17% of the cases. MC grew in pure culture in 28 specimens (46.6%). In 23% of cases MC was isolated with Streptococcus pneumoniae and in 21% with Haemophilus influenzae. Fifty-two stocks (86.6%) produced beta-lactamase. Twelve patients had a clinical diagnosis of pneumonia, 8 of them had an underlying chronic respiratory disease. Other 24 patients with an underlying chronic respiratory disease had a bronchial infection as a cause of exacerbation of their respiratory disease. Seven patients without an underlying chronic respiratory disease had a clinical episode of acute bronchitis. Finally, in 9 patients the isolation of MC was considered a colonization. CONCLUSIONS: In 17% cases MC was identified as a gram-positive cocci in the Gram stain, which may cause false diagnosis. The etiological importance of MC in episodes of acute exacerbation of patients with an underlying chronic respiratory disease is high.     

Anisotropy of wall energy in orthoferrites

Wall anisotropy causes bubble domains to be elliptical. A formula relating the eccentricity of an elliptical bubble to the anisotropic wall energy is derived, and an experimental technique for measuring the wall anisotropy is described. In Sm0.55Tb0.45FeO3a measured anisotropy energy of 1.7 percent of the wall-energy density at room temperature is responsible for eccentricities as large as 0.4 at average bubble radii equal to 85 percent of the bubble strip-domain transition radius. The relationship between material parameters and wall-energy anisotropy is briefly discussed.     

Localization and noise in edge detection

Two aspects of edge detection are analyzed, namely accuracy of localization and sensitivity to noise. The detection of corners and trihedral vertices is analyzed for gradient schemes and zero-crossing schemes. It is shown that neither scheme correctly detects corners of trihedral vertices, but that the gradient schemes are less sensitive to noise. A simple but important conclusion is that the noise present in digital images of typical indoor scenes is small and the signal-to-noise ratio is high. The noise present in digital images is so small as to make the performances of a variety of filters almost indistinguishable. As a consequence small filters can be used and the exact shape of the filter is not critical     

Towards a single model of efficient computation in real parallel machines

We propose a model of parallel computation, the YPRAM, that allows general parallel algorithms to be designed for a wide class of parallel models. The basic model captures locality among processors, which is measured as a function of two parameters; latency and bandwidth.

We design YPRAM algorithms for solving several fundamental problems: parallel prefix, sorting, sorting numbers from a bounded range, and list ranking. We show that our model predicts, reasonably accurately, the actual known performances of several basic parallel models — PRAM, hypercube, mesh and tree — when solving these problems.     

In vitro determination of cytotoxic drug response in ovarian carcinoma using the fluorometric microculture cytotoxicity assay (FMCA)

The fluorometric microculture cytotoxicity assay (FMCA), a short-term in vitro assay based on the concept of total tumor cell kill, was used for testing the cytotoxic drug sensitivity of tumor cells from patients with ovarian carcinoma. A total of 125 fresh specimens was obtained, 98 (78%) of which were analyzed successfully. Data from 45 patients were available for clinical correlations. The FMCA appeared to yield clinically relevant cytotoxic drug sensitivity data for ovarian carcinoma as indicated by a comparison with tumor samples obtained from patients with non-Hodgkin's lymphoma or kidney carcinoma. Considering the most active single agent in vitro actually given in vivo, and using the median drug activity among all ovarian carcinoma samples as a cut-off, the sensitivity of the assay and its specificity were 75 and 52%, respectively. Cross-resistance in vitro was frequently observed between standard drugs but not between standard drugs and Taxol. Ten percent of the specimens showed an extreme resistance for at least 4 of 6 of the drugs investigated.     

Molecular identification of sympatric chromosomal forms of Anopheles gambiae and further evidence of their reproductive isolation

In presented paper a review of recent articles regarding applicability of computerized rhinomanometry in modern rhinological diagnostics was done. A conclusion of discussed opinions is that at the time it is no agreement about clinical value of rhinomanometry. There are however some applications, in which rhinomanometry seems to have proved its usefulness.