Salmonella in surface and drinking water: Occurrence and water-mediated transmission

Salmonella is one of the leading causes of intestinal illness all over the world as well as the etiological agent of more severe systemic diseases such as typhoid and paratyphoid fevers. While water is known to be a common vehicle for the transmission of typhoidal Salmonella serovars, non-typhoidal salmonellae are mainly known as foodborne pathogens. This paper provides a brief review of the last ten years of peer reviewed publications on the prevalence of Salmonella in natural freshwaters and drinking waters, and on the relevance of these sources for Salmonella dissemination. In industrialized countries, Salmonella was rarely reported in water-borne outbreaks despite it being frequently detected in surface waters including recreational waters and waters used for irrigation or as a drinking water source. Consistent contamination with irrigation waters has been shown to be a common route of crop contamination in produces related Salmonella outbreaks. Multiple drug resistant (MDR) Salmonella strains, that represent an increased hazard for human health and that may contribute to the dissemination of drug resistances were also detected in surface water in developed countries. Surface runoff was shown to play a main role as driver of Salmonella load in surface waters. Accordingly, analysis of serovars indicated a mixed human and animal origin of Salmonella contribution to surface waters, emphasizing the role of wild life animals in water contamination. Data relating to Salmonella prevalence in surface and drinking water in developing countries are quite rare. Nevertheless, data on water-borne outbreaks as well as case control studies investigating the risk factors for endemic typhoid fever confirmed the relevance of water as source for the transmission of this disease. In addition epidemiological studies and Salmonella surveys, consistently provided an undeniable evidence of the relevance of MDR Salmonella Typhi strains in water-borne typhoid fever in developing countries.     

New fluorescent elastomeric materials based on synthetic and natural epoxidized rubbers

New fluorescent elastomeric materials were successfully prepared by reaction of an excited state intramolecular proton transfer-exhibiting silyl-functionalized benzothiazole dye with synthetic and natural epoxidized rubbers. The fluorescence emission and excitation spectra were obtained from the dye and the elastomeric materials to characterize its photophysical behavior. The benzothiazole derivative is fluorescent in the yellow region and presents a Stokes shift of 188 nm (solution) and 198 nm (solid state). After purification, the obtained materials from epoxidized rubbers presented excitation and emission maxima located at 358 nm and 550 nm, respectively, with a Stokes shift of 192 nm. The fluorescent dye could not be extracted from these films by solubilization–precipitation procedure, indicating the presence of covalent bonding between the dye and the matrix. On the other hand, the dye could be readily washed out of films that had been prepared using the corresponding nonepoxidized rubbers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Specification and use of concern metrics for supporting modularity-oriented modernizations

Software Quality Journal - Bad modularized concerns are a known deficiency of legacy systems, making their maintenance increasingly harder and expensive. An alternative is to conduct a...     

Kinetic study on the thermal degradation of heavy oil in presence of SBA-15 containing aluminum and cerium

In research for materials that can be applied in processing heavy oil (petroleum), this work proposes to synthesize mesoporous heterogeneous catalysts, type SBA-15, with the addition of cerium metal and aluminum. These catalysts were characterized by X-ray diffraction, scanning electron micrographs coupled to energy dispersive spectrometry, spectroscopy in the infrared region by Fourier transform, N₂ adsorption and desorption and thermal analysis-thermogravimetry. Thermal tests were performed to evaluate the thermal and catalytic degradation process with a sample of heavy oil (°API = 14). Through the non-isothermal kinetic model of Ozawa Flynn Wall (OFW) some parameters for determining the apparent activation energy of decomposition were obtained. The petroleum with 12% of Ce₅Al₅₀SBA-15 showed a catalytic activity for this material. It has been seen that there was a decrease in the Ea in model free of the order from 89.0 to 104.9 kJ mol^?1 in α = 50% ± 10%, and it was repeated from the first percentage until the last showing performance of Ce₅Al₅₀SBA-15 as a catalyst.     

Inhibition vs. enhancement of the nitrate-induced phototransformation of organic substrates by the OH scavengers bicarbonate and carbonate

Contrary to common expectations, the hydroxyl scavengers, carbonate and bicarbonate, are able to enhance the phototransformation by nitrate of a number of substituted phenols. Carbonate and bicarbonate, in addition to modifying the solution pH, are also able to induce a considerable formation of the carbonate radicals upon nitrate photolysis. The higher availability of less-reactive species than the hydroxyl radical would contribute to substantially enhance the photodegradation of the phenols/phenolates that are sufficiently reactive toward the carbonate radical. This phenomenon has a potentially important impact on the fate of the relevant compounds in surface waters. In contrast, the degradation of compounds that are not sufficiently reactive toward CO₃^−• is inhibited by carbonate and bicarbonate because of the scavenging of ^•OH.     

Bacteriorhodopsin-based Langmuir-Schaefer films for solar energy capture

The photovoltaic (PV) solar cell, converting incident solar radiation directly into electrical energy, today represents the most common power source for the Earth-orbiting spacecraft, and the utilization of organic materials in this context is here explored in comparison with the present state of the art placing emphasis in organic nanotechnology. Poly[3-3'(vinylcarbazole)] (PVK) was synthesized by oxidative polymerization with ferric chloride of N-vinylcarbazole. The resulting polymer was then deposited on solid support by using the Langmuir-Schaefer (LS) technique. The pressure-area isotherm of PVK revealed the possibility of compact monolayer formation at the air-water interface. Different layers of PVK were doped with iodine vapors. The cyclic voltammetry investigation of PVK-doped I/sub 2/ showed a distinctive electrochemical behavior. The photoinduced charge transfer across a donor/acceptor (D/A) hybrid interface provided an effective method to study the PV properties of the composite LS films. The results are compared with other approaches within the biological framework, such as bacteriorhodopsin (BR), and organic nanostructured materials.     

Prevalence of scleroderma spectrum disorders in the general population of Estonia

RATIONALE AND OBJECTIVES: The authors compared the economic effect of stereotactic core needle biopsy (CNB) with that of short-term unilateral surveillance mammography in the management of probably benign breast lesions detected during routine screening mammography. METHODS: Published data with regard to the cost of stereotactic CNB and unilateral mammography were applied to 3,184 patients who underwent surveillance mammography; including 161 patients who underwent biopsy. Costs of immediate tissue diagnosis were compared with costs of surveillance with use of ratios of published reimbursement scales to minimize geographic variations. Sensitivity analyses were applied to this ratio. RESULTS: The cost of managing probably benign breast lesions with surveillance mammography was $3,307,575 less than if all lesions had been managed with CNB. The ratio of the cost of CNB to the cost of surveillance mammography was 8:1. This ratio is more sensitive to the frequency of use of CNB than to reimbursement schedules. CONCLUSION: With similar false-negative rates, CNB is more costly than surveillance and has a negative effect in the management of probably benign breast lesions, unless interval change during surveillance prompts tissue diagnosis.