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991.
992.
Garin B Gouali M Wouafo M Perchec AM Pham MT Ravaonindrina N Urbès F Gay M Diawara A Leclercq A Rocourt J Pouillot R 《International journal of food microbiology》2012,157(1):102-107
Quantitative data on Campylobacter contamination of food are lacking, notably in developing countries. We assessed Campylobacter contamination of chicken neck-skins at points of slaughter in 5 major cities in Africa (Dakar in Senegal, Yaounde in Cameroon), Oceania (Noumea in New Caledonia), the Indian Ocean (Antananarivo in Madagascar) and Asia (Ho Chi Minh City (HCMC) in Vietnam. One hundred and fifty slaughtered chickens were collected in each of the 5 major cities from semi-industrial abattoirs or markets (direct slaughter by the seller), and 65.5% (491/750) were found to be Campylobacter-positive. Two cities, Yaounde and Noumea, demonstrated high prevalence Campylobacter detection rates (92.7% and 96.7% respectively) in contrast with HCMC (15.3%). Four species were identified among 633 isolates, namely C. jejuni (48.3%), C. coli (37.3%), C. lari (11.7%) and C. upsaliensis (1%). HCMC was the only city with C. lari isolation as was Antananarivo for C. upsaliensis. C. coli was highly prevalent only in Yaounde (69.5%). Among the 491 samples positive in Campylobacter detection, 329 were also positive with the enumeration method. The number of Campylobacter colony-forming units (CFU) per gram of neck-skin in samples positive in enumeration was high (mean of the log(10): 3.2 log(10) CFU/g, arithmetic mean: 7900CFU/g). All the cities showed close enumeration means except HCMC with a 1.81 log(10) CFU/g mean for positive samples. Semi-industrial abattoir was linked to a significant lower count of Campylobacter contamination than direct slaughter by the seller (p=0.006). On 546 isolates (546/633, 86.3%) tested for antibiotic susceptibility, resistance to erythromycin, ampicillin and ciprofloxacin was observed for respectively 11%, 19% and 50%. HCMC was the city where antibiotic resistant rates were the highest (95%, p=0.014). Considering the 329 positive chickens in Campylobacter enumeration, the mean number of resistant isolates to at least 2 different antibiotic families (19.8%), may be estimated ca. 1500CFU/g; the corresponding mean of the log(10) would be 2.5 log(10)CFU/g. As chickens are sold at slaughter and brought directly at home to be cooked, these data suggest a high probability of cross-contamination. A substantial proportion of isolates are drug-resistant, which could lead to potential public health issues. Health authorities should consider measures to reduce Campylobacter contamination of chicken during farming and at slaughter, and to provide appropriate food hygiene education. Further studies are needed in particular to investigate food-handling practices in domestic kitchens. 相似文献
993.
An investigation of dehazing effects on image and video coding 总被引:1,自引:0,他引:1
This paper makes an investigation of the dehazing effects on image and video coding for surveillance systems. The goal is to achieve good dehazed images and videos at the receiver while sustaining low bitrates (using compression) in the transmission pipeline. At first, this paper proposes a novel method for single-image dehazing, which is used for the investigation. It operates at a faster speed than current methods and can avoid halo effects by using the median operation. We then consider the dehazing effects in compression by investigating the coding artifacts and motion estimation in cases of applying any dehazing method before or after compression. We conclude that better dehazing performance with fewer artifacts and better coding efficiency is achieved when the dehazing is applied before compression. Simulations for Joint Photographers Expert Group images in addition to subjective and objective tests with H.264 compressed sequences validate our conclusion. 相似文献
994.
Askwar Hilonga Jong-Kil Kim Pradip B. Sarawade Dang Viet Quang Godlisten Shao Gideon Elineema Hee Taik Kim 《Powder Technology》2012
In this study a simple and reproducible method was used to develop silver-doped silica powder with antibacterial properties. Silica matrices were synthesized via a sol–gel route which allows one to easily tailor textural and chemical properties. A wide range of silica-materials/products was obtained via the present route. These are: pure silver nanoparticles (Ag0), silver in ionic state (Ag+), AgCl nanoparticles, and the mixture of Ag0 and AgCl. The efficacy of these products were tested against Escherichia coli and the results demonstrate that materials that are suitable for antibacterial applications were obtained by this newly developed technique while utilizing sodium silicate, which is relatively inexpensive, as a silica precursor. This may significantly boost the industrial production of the inexpensive silver-doped silica products for various applications. A project on other innovative industrial applications of our products is in progress. 相似文献
995.
The decomposition of H(2)O(2) on iron minerals can generate ?OH, a strong oxidant that can transform a wide range of contaminants. This reaction is critical to In Situ Chemical Oxidation (ISCO) processes used for soil and groundwater remediation, as well as advanced oxidation processes employed in waste treatment systems. The presence of dissolved silica at concentrations comparable to those encountered in natural waters decreases the reactivity of iron minerals toward H(2)O(2), because silica adsorbs onto the surface of iron minerals and alters catalytic sites. At circumneutral pH values, goethite, amorphous iron oxide, hematite, iron-coated sand, and montmorillonite that were pre-equilibrated with 0.05-1.5 mM SiO(2) were significantly less reactive toward H(2)O(2) decomposition than their original counterparts, with the H(2)O(2) loss rates inversely proportional to SiO(2) concentrations. In the goethite/H(2)O(2) system, the overall ?OH yield, defined as the percentage of decomposed H(2)O(2) producing ?OH, was almost halved in the presence of 1.5 mM SiO(2). Dissolved SiO(2) also slowed H(2)O(2) decomposition on manganese(IV) oxide. The presence of dissolved SiO(2) results in greater persistence of H(2)O(2) in groundwater and lower H(2)O(2) utilization efficiency and should be considered in the design of H(2)O(2)-based treatment systems. 相似文献
996.
997.
Binayak Bhandari Young-Sun Hong Hae-Sung Yoon Jong-Seol Moon Minh-Quan Pham Gyu-Bong Lee Yuchu Huang Barbara S. Linke D.A. Dornfeld Sung-Hoon Ahn 《Precision Engineering》2014
A drilling burr-control chart (DBCC), based on experimental results, is a tool for the prediction and control of drilling burrs for a large range of drilling parameters. A micro-drilling burr-control chart (M-DBCC) was developed for a standard double-sided copper-clad laminated (CCL) printed circuit board (PCB) with laminated fiber-reinforced plastic (FRP) substrate. This chart will assist in the selection of favorable drilling parameters for predicting and achieving preferred types of burrs. Burr classification was carried out according to the burr geometric characteristics, burr formation mechanisms, burr height, and drill bit breakage while drilling. The design of experiment (DOE) technique based on the Taguchi method was used to find the most significant drilling parameter affecting burr height. The results show that the drill diameter makes a statistically significant contribution to burr-height variation. 相似文献
998.
R. Keivani M. Jahazi T. Pham A. R. Khodabandeh M. R. Afshar 《The International Journal of Advanced Manufacturing Technology》2014,73(1-4):409-419
A three-dimensional thermomechanical finite element (FE) analysis is carried out to model and predict the influence of welding sequence on the generation of distortions and residual stresses in large size T-joints. To simulate industrial welding conditions, the influence of nine welding sequences on the magnitude of distortion in both the plate and the stiffener was investigated. The addition of new material during welding was simulated using an element “birth and death” technique, while the moving welding arc was considered as a volumetric heat source with a double ellipsoidal distribution. The investigated material is a structural steel used for fabrication of large size structures in the hydroelectric industry. To calibrate the model and validate the simulation results, welding-induced distortion for one sequence was initially modeled and the results were compared with experimental measurements. The optimum welding sequences for the base plate and the reinforcement plate were determined. The results indicated also that the predicted distortions obtained from three-dimensional FE analysis are in reasonable agreement with experimental measurements. 相似文献
999.
1000.
In the 1999 AISC-LRFD, the in-filled concrete strength of concrete-filled tube (CFT) columns is limited to a maximum value of 55 MPa (N/mm2). That limiting value is raised to 70 MPa in the 2005 AISC-LRFD. This study aims to assess if the LRFD CFT column formulas are applicable to intermediate to long rectangular columns with higher concrete strengths. Twenty four specimens with varying between 29 and 84 MPa were tested. Various formulas and relevant provisions for CFT columns as specified in the major design codes including AISC-LRFD, EC 4, AS-5100, and CSA S16-01 were examined and compared. The design CFT strength (Pu) predicted by the AISC-LRFD formulas and the test results were found to be in good agreement. The higher limiting value of 70 MPa proposed in the 2005 AISC-LRFD appears acceptable. The test results reveal that the 1999 AISC-LRFD design strengths are conservative and tend to penalize these CFT columns with higher concrete strength. 相似文献