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排序方式: 共有464条查询结果,搜索用时 15 毫秒
1.
Iratxe Perez-Arnedo María J. Cantalejo Alba Martínez-Laorden Elena Gonzalez-Fandos 《International Journal of Food Science & Technology》2021,56(4):1855-1864
Microbiological contamination of chicken meat depends on the conditions under which the animals are reared, slaughtered and processed. The aim of this study was to determine the influence of farm origin and processing stages at slaughterhouse on the microbial safety and quality of chicken. Samples of chicken carcasses from three different farms were taken from a slaughterhouse. Mesophiles, Escherichia coli, coagulase positive Staphylococcci counts, presence of Listeria monocytogenes,Campylobacter and Salmonella were determined at five sampling points: after defeathering, after evisceration, after washing, after chilling and after cutting. Chilling reduced log numbers of mesophiles, coagulase positive Staphylococci and E. coli by 0.85, 1.52 and 2.2 log units, respectively. Salmonella was not detected after chilling. High prevalence of Campylobacter spp was observed at all the stages ranging between 84% and 100%. L. monocytogenes was not detected in chicken carcasses after defeathering. However, it was detected after evisceration and after washing and chilling. The most critical stage for L. monocytogenes contamination was the portioning operation, the prevalence in breast and legs being 88% and 84%, respectively. 相似文献
2.
Myriam Gonzlez María Ovejero-Snchez Alba Vicente-Blzquez Raquel lvarez Ana B. Herrero Manuel Medarde Rogelio Gonzlez-Sarmiento Rafael Pelez 《International journal of molecular sciences》2021,22(4)
Pan-Gyn cancers entail 1 in 5 cancer cases worldwide, breast cancer being the most commonly diagnosed and responsible for most cancer deaths in women. The high incidence and mortality of these malignancies, together with the handicaps of taxanes—first-line treatments—turn the development of alternative therapeutics into an urgency. Taxanes exhibit low water solubility that require formulations that involve side effects. These drugs are often associated with dose-limiting toxicities and with the appearance of multi-drug resistance (MDR). Here, we propose targeting tubulin with compounds directed to the colchicine site, as their smaller size offer pharmacokinetic advantages and make them less prone to MDR efflux. We have prepared 52 new Microtubule Destabilizing Sulfonamides (MDS) that mostly avoid MDR-mediated resistance and with improved aqueous solubility. The most potent compounds, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methylaminobenzenesulfonamide 38, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 42, and N-benzyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 45 show nanomolar antiproliferative potencies against ovarian, breast, and cervix carcinoma cells, similar or even better than paclitaxel. Compounds behave as tubulin-binding agents, causing an evident disruption of the microtubule network, in vitro Tubulin Polymerization Inhibition (TPI), and mitotic catastrophe followed by apoptosis. Our results suggest that these novel MDS may be promising alternatives to taxane-based chemotherapy in chemoresistant Pan-Gyn cancers. 相似文献
3.
M Loscertales Abril F Jaldo Alba E Díaz Lucas E Narbona López A Ruiz Extremera E Ocete Hita JA Molina Font 《Canadian Metallurgical Quarterly》1993,39(4):339-342
Four patients who complained of symptoms and signs compatible with biliary tract disease and in whom the diagnosis of gallbladder (three cases) and common bile duct ascariasis (one case) was made sonographically are reported. In two patients with gallbladder ascariasis, cholecystectomy corroborated the presence of the round-worms, and was curative. The third patient was a pregnant woman (32nd gestational week) who took piperazine citrate, and a second sonogram performed 29 days later was completely normal. The fourth patient with common bile duct ascariasis underwent choledochotomy with extraction of one ascaris lumbricoides from the common duct, and a T tube was left in place for 15 days. All patients received antiparasitics and had a favorable outcome. Ultrasonography is an important noninvasive diagnostic procedure in the work-up of these patients, who usually describe a clinical picture suggesting gallstone disease: this is especially true in the presence of pregnancy. 相似文献
4.
Zirconia-supported alkali ions, containing Na, from 0.74 to 3.61 wt.%, and K, from 0.91 to 4.76 wt.%, have been studied by X-Ray Photoelectron Spectroscopy, X-ray diffraction and chemical analyses. The results show that the alkali ions remain dispersed on the zirconia surface. After treatment at 773 K in air, 5h, the Na containing samples maintain a good dispersion at low Na content, whereas for the more concentrated samples, agglomeration and incorporation in solid solution have been detected. The K based system shows neither agglomeration nor incorporation in solid solution of potassium ions. The XPS intensity ratios are compared with calculated values, according to different models, to account for the changes in surface morphology. 相似文献
5.
M.?MelgosaEmail author R.?Huertas E.?Hita J.?M.?Roa F.?J.?Heredia J.?Alba M.?J.?Moyano 《Journal of the American Oil Chemists' Society》2004,81(4):323-330
A new color scale was developed from a broad data set of 1700 virgin olive oil samples over four crop seasons, which can be
considered highly representative of the whole color range of virgin olive oils available in Spain. This color scale provides
a new set of 60 color standards, improving the results achieved by the old 60-color standards proposed by the bromthymol blue
method. Seeking the greatest possibility of including a near match between colors of virgin olive oils and proposed standards,
we developed our new color scale using a recent uniform color space, with standards placed in a regular rhombohedral lattice
like the one employed by the Uniform Color Scales of the Optical Society of America. The average color difference between
each of the 1700 virgin olive oils and its nearest standard is reduced from 8.17 CIELAB units, using the bromthymol blue standards,
to 3.99 CIELAB units using the new standards. Within a color tolerance of 7.0 CIELAB units, 93.2% of our virgin olive oils
can be classified with the new standards, but only 59.1% with the bromthymol blue ones. In the interest of future adoption,
the performance of the new color standards should be tested by industry and researchers. 相似文献
6.
In this paper we propose a genetic algorithm (GA) for solving the DNA fragment assembly problem in a computational grid. The algorithm, which is named GrEA, is a steady-state GA which uses a panmitic population, and it is based on computing parallel function evaluations in an asynchronous way. We have implemented GrEA on top of the Condor system, and we have used it to solve the DNA assembly problem. This is an NP-hard combinatorial optimization problem which is growing in importance and complexity as more research centers become involved on sequencing new genomes. While previous works on this problem have usually faced 30 K base pairs (bps) long instances, we have tackled here a 77 K bps long one to show how a grid system can move research forward. After analyzing the basic grid algorithm, we have studied the use of an improvement method to still enhance its scalability. Then, by using a grid composed of up to 150 computers, we have achieved time reductions from tens of days down to a few hours, and we have obtained near optimal solutions when solving the 77 K bps long instance (773 fragments). We conclude that our proposal is a promising approach to take advantage of a grid system to solve large DNA fragment assembly problem instances and also to learn more about grid metaheuristics as a new class of algorithms for really challenging problems. 相似文献
7.
This article addresses a new dynamic optimization problem (DOP) based on the Predator-Prey (PP) relationship in nature. Indeed, a PP system involves two adversary species where the predator’s objective is to hunt the prey while the prey’s objective is to escape from its predator. By analogy to dynamic optimization, a DOP can be seen as a predation between potential solution(s) in the search space, which represents the predator, and the moving optimum, as the prey. Therefore we define the dynamic predator-prey problem (DPP) whose objective is to keep track of the moving prey, so as to minimize the distance to the optimum. To solve this problem, a dynamic approach that continuously adapts to the changing environment is required. Accordingly, we propose a new evolutionary approach based on three main techniques for DOPs, namely: multi-population scheme, random immigrants, and memory of past solutions. This hybridization of methods aims at improving the evolutionary approaches ability to deal with DOPs and to restrain as much as possible their drawbacks. Our computational experiments show that the proposed approach achieves high performance for DPP and and competes with state of the art approaches. 相似文献
8.
El‐Ghazali Talbi Matthieu Basseur Antonio J. Nebro Enrique Alba 《International Transactions in Operational Research》2012,19(1-2):283-305
In recent years, the application of metaheuristic techniques to solve multi‐objective optimization problems has become an active research area. Solving this kind of problems involves obtaining a set of Pareto‐optimal solutions in such a way that the corresponding Pareto front fulfils the requirements of convergence to the true Pareto front and uniform diversity. Most of the studies on metaheuristics for multi‐objective optimization are focused on Evolutionary Algorithms, and some of the state‐of‐the‐art techniques belong this class of algorithms. Our goal in this paper is to study open research lines related to metaheuristics but focusing on less explored areas to provide new perspectives to those researchers interested in multi‐objective optimization. In particular, we focus on non‐evolutionary metaheuristics, hybrid multi‐objective metaheuristics, parallel multi‐objective optimization and multi‐objective optimization under uncertainty. We analyze these issues and discuss open research lines. 相似文献
9.
Dania Esposito Andrea Margonelli Emanuela Pace Maria Teresa Giardi Cecilia Faraloni Giuseppe Torzillo Alba Zanini 《Microgravity science and technology》2006,18(3-4):215-218
Photosynthetic microorganisms are expected to be useful to maintain an oxygenic atmosphere and to provide biomass for astronauts in the International Space Station as well as in future long-term space flights. However, fluxes of complex ionizing radiation of various intensities and energies make space an extreme environment for the microorganisms, affecting their photosynthetic efficiency. To automatically monitor the photosynthetic Photosystem II (PSII) activity of microorganisms under space conditions an optical biosensor, which utilizes chlorophyll fluorescence as biological transduction system, was built; the PSII activity was monitored by the biosensor during balloon flights at stratospheric altitudes of about 40 km. The effect of space stress on quantum yield of PSII varied among the tested species depending on the growth light conditions at which they were exposed during the flights. 相似文献
10.
A parallel micro evolutionary algorithm for heterogeneous computing and grid scheduling 总被引:1,自引:0,他引:1
This work presents a novel parallel micro evolutionary algorithm for scheduling tasks in distributed heterogeneous computing and grid environments. The scheduling problem in heterogeneous environments is NP-hard, so a significant effort has been made in order to develop an efficient method to provide good schedules in reduced execution times. The parallel micro evolutionary algorithm is implemented using MALLBA, a general-purpose library for combinatorial optimization. Efficient numerical results are reported in the experimental analysis performed on both well-known problem instances and large instances that model medium-sized grid environments. The comparative study of traditional methods and evolutionary algorithms shows that the parallel micro evolutionary algorithm achieves a high problem solving efficacy, outperforming previous results already reported in the related literature, and also showing a good scalability behavior when facing high dimension problem instances. 相似文献