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41.
The aim of this study was to assess the hygiene practices of food handlers in municipal schools of Natal, Brazil, where 27 public schools were evaluated, using a checklist and microbiological analysis of hands. It was found that 74.1% of the handlers did not receive periodic training, 51.9% did not undergo annual health examinations and 100% did not practice proper hand hygiene, a situation that reflected significantly (p < 0.05) in hand contamination, in which fecal coliforms were detected on 55.6% of the hands analyzed. It was concluded that the schools studied did not have appropriate hygienic conditions, suggesting the need for interventions that ensure the quality of school food served to the children.  相似文献   
42.
This paper deals with the evaluation of the recommendation functionality inside a connected consumer electronics product in prototype stage. This evaluation is supported by a framework to access and analyze data about product usage and user experience. The strengths of this framework lie in the collection of both objective data (i.e., “What is the user doing with the product?”) and subjective data (i.e., “How is the user experiencing the product?”), which are linked together and analyzed in a combined way. The analysis of objective data provides insights into how the system is actually used in the field. Combined with the subjective data, personal opinions and evaluative judgments on the product quality can be then related to actual user behavior. In order to collect these data in a most natural context, remote data collection allows for extensive user testing within habitual environments. We have applied our framework to the case of an interactive TV recommender system application to illustrate that the user experience of recommender systems can be evaluated in real-life usage scenarios.  相似文献   
43.
Upon fractionation of a post mitochondrial supernatant from rat liver, phosphorylase kinase activity was largely recovered in the cytosol and the smooth endoplasmic reticulum (SER) fraction. The presence of phosphorylase kinase in SER vesicles was not due to an interaction of the enzyme with glycogen particles, since previous elimination of SER glycogen either by 48 h animal starvation or by treatment of the membrane fraction with alpha-amylase did not significantly alter phosphorylase kinase activity content. Washing of the initial pellet of SER fraction (crude SER) by dilution and recentrifugation, released in the supernatant an amount of phosphorylase kinase activity, which is dependent on: i) the degree of dilution, ii) the number of washes, iii) the ionic strength of the washing solution and iii) the presence or absence of Ca2+. Crude SER-associated phosphorylase kinase was marginally affected by increased concentrations of antibody against rabbit skeletal muscle holoenzyme which nevertheless drastically inhibited cytosolic enzyme activity, while it showed a higher resistance to partial proteolysis and a different Western blotting profile with anti-phosphorylase kinase when compared with the soluble kinase. A small but significant fraction of SER phosphorylase kinase was strongly associated with the microsomal fraction being partly extractable only in presence of detergents. This membrane-bound enzyme form exhibited an alkaline pH optimum, in contrast to the neutral pH optima of both soluble and weakly associated phosphorylase kinase.  相似文献   
44.
A ternary alloy Ni–W–Co was electrodeposited and operational parameters in relation to its corrosion resistance and deposition efficiency were optimized. A 22 full factorial design was successfully employed for experimental design analysis of the results. By means of response surface analysis, the statistical model identified the following operating conditions for obtaining corrosion resistant alloy: 60 mA/cm2 current density, 70 °C temperature, 20 rpm cathode rotation and 8.0 pH. The alloy was deposited at 36% current efficiency, with an average composition of 70% Ni, 8% Co, 22% W and traces of boron and with E corr −0.508 V and R p 4.56 × 104 Ohm. The deposit obtained under these conditions had an amorphous character and showed good adherence, high corrosion resistance and presence of nodules on its surface. Electrochemical corrosion tests verified that the Ni–W–Co alloy had better corrosion resistance than similarly electrodeposited Co–W amorphous alloy.  相似文献   
45.
This paper presents an original method of synthesis of mixed tantalum and niobium carbides from an oxalic precursor elaborated from the tantalite mineral (Fe,Mn)(Ta1–x Nb x )2O6. The process of elaboration consists initially in melting the ore with potassium pyrosulphate, then performing a lixiviation with a concentrated hydrochloric acid solution. During the latter reaction, iron and manganese oxides are converted into water-soluble chlorides while the fused mass containing potassium, niobium and tantalum is not dissolved. Traces of chlorides are eliminated by filtration with boiling aqueous solution. Then, the solid is dissolved slowly in hot concentrated sulphuric acid solution. Adding ammonium hydroxide up to a pH of 8 completes the precipitation of niobium and tantalum hydroxides. The precipitate (Ta1–x Nb x )(OH)5 is washed and submitted to a reaction of complexation with oxalate ions in an aqueous environment. This reaction involves the formation of a water-soluble oxalic complex containing tantalum and niobium. The excess of water is eliminated by evaporation at 333 K. The tantalum and niobium carbides are obtained by submitting the oxalic complex of chemical formula (NH4)3(Ta1–x Nb x )O(C2O4) nH2O to a gas-solid reaction in a methane-hydrogen atmosphere at 1273 K. The oxalic precursor and their resultant mixed carbides are characterized by atomic absorption and Infra-Red spectroscopies, thermogravimetric-differential thermal analysis coupled, laser granulometry, X-ray diffraction and transmission electronic microscopy.  相似文献   
46.
The interaction of methotrexate (MTX) with beta-cyclodextrin (β-CD) in the presence of triethanolamine (TEA) was investigated with the aim to elucidate the mechanism whereby self-assembly cyclodextrin systems work in association with this third component. Solubility diagram studies showed synergic increment of the MTX solubility to be about thirty-fold. Experiments using 2D ROESY and molecular modeling studies revealed the inclusion of aromatic ring III of the drug into β-CD cavity, in which TEA contributes by intensifying MTX interaction with β-CD and stabilizes MTX:β-CD:TEA ternary complex by electrostatic interaction. The maintenance of these interactions in solid phase was also studied in ternary MTX:β-CD:TEA and comparisons were made with freeze dried binary MTX:β-CD and physical mixtures. FTIR studies evidenced that MTX–β-CD interaction remained in solid ternary complexes, which was also supported by thermal (differential scanning calorimetry (DSC), thermogravimetric analysis (TG)/first derivative of TG analysis (DTG) and C,N,H elementary analysis) and structural (X-ray diffraction analysis, (XRD)) studies, mainly regarding the increment of drug stability. The efficient in vitro drug dissolution studies successfully demonstrated the contribution of ternary complexes, which highlights the importance of this possible new raw material for further applications in drug delivery systems.  相似文献   
47.
48.
This work deals with the rheological, morphological, and thermal properties of composites having poly(ethylene terephthalate) (PET), polyamide-6 (PA6), and their blends as matrices, and rice husk ash (RHA) as a filler. The study determines the effect of composition on the change in viscosity and rate of degradation during processing in a torque rheometer. Our data indicates that thermal stability and degradation during processing depend on matrix composition and filler concentration. SEM micrographs show both partial adhesion of the filler to the matrices and filler pullout. Optical microscopy shows particle agglomeration and that agglomerate size increased with filler content. FTIR investigates the shifting of absorption bands of PET/PA6 composite after the addition of RHA and attributes the selective dispersion of RHA to the formation of hydrogen bonds. Our data supports the idea that filler employed here is an option to develop polymer composites with improved properties.  相似文献   
49.
Hg/sub 0.82/Re/sub 0.18/Ba/sub 2/Ca/sub 2/Cu/sub 3/O/sub 8+/spl delta// polycrystalline samples were successfully obtained by using different oxygen partial pressure in the annealing treatment of the precursor ceramic. The doping state was confirmed by X-ray powder diffraction pattern analysis and by observing distinct thermopower values at room temperature. Also, the intergrain regions have shown an improvement in the critical current density when using the precursor preparation with 10% O/sub 2/ and 90% Ar (optimal doped). The optimal doped sample has presented the highest /spl alpha/ exponent of the J/sub c//spl prop/[1-(T/T/sub c/)/sup 2/]/sup /spl alpha// dependence. For the case of (Hg,Re)-1223 polycrystalline superconductor applications, the /spl alpha/ exponent can be used as a junction quality parameter.  相似文献   
50.
PURPOSE: To develop a systematic method for identifying and grading age-related macular degeneration (ARMD) in human donor eyes, postmortem fundus appearance was compared with histopathologic assessment in eyes with a spectrum of age-related macular change. METHODS: Eyes without grossly visible, late ARMD were obtained from 8 cancer patients and 26 donors older than 50 years. Postmortem fundus appearance was graded for drusen and pigmentary change, using stereo color photographs. Eyes were processed and sectioned at 1 microm for histopathologic evaluation of macular retinal pigment epithelium-Bruch's membrane complex. The histologic diagnosis was compared with gross fundus appearance, clinical ophthalmic histories (n = 25), and clinical fundus photographs that were graded using the Wisconsin Age-related Maculopathy Grading System (n = 5). RESULTS: Ten eyes met histopathologic criteria for early ARMD. A similar proportion of eyes (27%-32%) was identified as affected by ARMD by other published histopathologic criteria. By choosing eyes with at least one druse larger than 125 microm in diameter or an area of pigment-clumping 500 microm in diameter that was visible in the postmortem fundus, ARMD cases were identified with 90% sensitivity and 95% specificity. CONCLUSIONS: The Alabama ARMD Grading System permits rational and standardized use of donor eyes in studies that are directed toward understanding the pathogenesis of ARMD.  相似文献   
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