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171.
A novel sanitizer composed of lactic acid and peroxyacetic acid (LA-PAA) was developed as an alternative to chlorinated water (CW) for fresh produce processing. Single strains of Lactobacillus plantarum, nonpathogenic Escherichia coli K-12, and Listeria innocua were used to demonstrate the microbial efficacy of LA-PAA. LA-PAA achieved a >7.8-log reduction of L. innocua and L. plantarum suspended in water at 4°C for 20 s, and LA, PAA, and CW achieved reductions of 0.4, 4.8, and 2.7 log, respectively. LA-PAA, when compared with LA, PAA, and CW, enhanced the reduction of L. innocua attached to romaine leaves by >2.2 log, and improved the removal of E. coli attached to spinach leaves by >2.4 log. The exponential improvement in the microbial efficacy of LA-PAA showed synergism between LA and PAA. LA-PAA microbial efficacy was inversely proportional to pH value and directly correlated with residence time and concentration. Despite an improvement in microbial reduction through the addition of surfactant to LA-PAA, the usage of surfactant in washing fresh produce was impeded by excessive foaming during actual processing. Effects of organic matter on the performance of LA-PAA were minimal. External sensory evaluations showed that LA-PAA had no negative effects on the quality of lettuce and tender leaves. Temperature-abuse studies demonstrated that LA-PAA reduced decay by ~50% when compared with CW. Overall, these results support the premise that LA-PAA has significant potential to be an alternative to CW for fresh produce processing. 相似文献
172.
Libkind D Moliné M Sommaruga R Sampaio JP van Broock M 《Yeast (Chichester, England)》2011,28(8):619-627
The synthesis of the UV Absorbing compounds named mycosporines (MYCs) has been detected in a few basidiomycetous yeast groups. Conspicuous accumulation of mycosporine-glutaminol-glucoside (MGG) in yeasts requires photo-induction and its photoprotective function has been postulated. The distribution of the ability to produce MYCs appeared to be related to the yeast taxonomic affiliation. In view of the potential significance of MYCs in yeast taxonomy, we here studied the distribution of this trait among dimorphic basidiomycetes of the Pucciniomycotina. Of the 94 fungal species (377 strains and 33 genera) tested, almost half were MYC-positive and MGG was the main compound produced. MGG synthesis was observed for representatives of five of seven Pucciniomycotina classes, indicating that this trait is widely distributed in this group. MGG detection proved useful for the differentiation of species of the polyphyletic genera, such as Rhodotorula and Sporobolomyces, that are phylogenetically separated. MGG quantification and UV tolerance studies in Cystobasidiomycetes supported the idea that the habitat of origin of each strains is important in the level of MGG synthesis and that MYCs have a photoprotective function in yeasts. The taxonomic value of this trait in fungal systematics is discussed. 相似文献
173.
Leandro Ezequiel Di Persia Diego Humberto Milone Masuzo Yanagida 《Journal of Signal Processing Systems》2011,63(3):333-344
In a recent publication the pseudoanechoic mixing model for closely spaced microphones was proposed and a blind audio sources
separation algorithm based on this model was developed. This method uses frequency-domain independent component analysis to
identify the mixing parameters. These parameters are used to synthesize the separation matrices, and then a time-frequency
Wiener postfilter to improve the separation is applied. In this contribution, key aspects of the separation algorithm are
optimized with two novel methods. A deeper analysis of the working principles of the Wiener postfilter is presented, which
gives an insight in its reverberation reduction capabilities. Also a variation of this postfilter to improve the performance
using the information of previous frames is introduced. The basic method uses a fixed central frequency bin for the estimation
of the mixture parameters. In this contribution an automatic selection of the central bin, based in the information of the
separability of the sources, is introduced. The improvements obtained through these methods are evaluated in an automatic
speech recognition task and with the PESQ objective quality measure. The results show an increased robustness and stability
of the proposed method, enhancing the separation quality and improving the speech recognition rate of an automatic speech
recognition system. 相似文献
174.
Bertanza G Pedrazzani R Dal Grande M Papa M Zambarda V Montani C Steimberg N Mazzoleni G Di Lorenzo D 《Water research》2011,45(8):2473-2484
A major source of the wide presence of EDCs (Endocrine Disrupting Compounds) in water bodies is represented by direct/indirect discharge of sewage. Recent scientific literature reports data about their trace concentration in water, sediments and aquatic organisms, as well as removal efficiencies of different wastewater treatment schemes. Despite the availability of a huge amount of data, some doubts still persist due to the difficulty in evaluating synergistic effects of trace pollutants in complex matrices. In this paper, an integrated assessment procedure was used, based on chemical and biological analyses, in order to compare the performance of two full scale biological wastewater treatment plants (either equipped with conventional settling tanks or with an ultrafiltration membrane unit) and tertiary ozonation (pilot scale).Nonylphenol and bisphenol A were chosen as model EDCs, together with the parent compounds mono- and di-ethoxylated nonylphenol (quantified by means of GC-MS). Water estrogenic activity was evaluated by applying the human breast cancer MCF-7 based reporter gene assay. Process parameters (e.g., sludge age, temperature) and conventional pollutants (e.g., COD, suspended solids) were also measured during monitoring campaigns.Conventional activated sludge achieved satisfactory removal of both analytes and estrogenicity. A further reduction of biological activity was exerted by MBR (Membrane Biological Reactor) as well as ozonation; the latter contributed also to decrease EDC concentrations. 相似文献
175.
Iribarren D Vázquez-Rowe I Hospido A Moreira MT Feijoo G 《The Science of the total environment》2011,409(8):1609-1611
Recent life cycle assessment studies have revealed the relevance of cooling agent leakage when assessing the greenhouse gas (GHG) emissions generated by fishing vessel operations. The goal of this communication is to update the carbon footprinting of the Galician fishing activity (NW Spain) by including the GHG emissions from cooling agent leakage. Results proved the relevant role played by refrigerants regarding their contribution to the carbon footprint of fishing activities. Thus, an overall increase of 13% was found when comparing the final global carbon footprint for the Galician fishing activity with previous calculations that did not include these emissions. Nevertheless, further efforts should be made in order to provide robust data in this respect. 相似文献
176.
于魁 Diego Perez 赵伟 Chie Fuyuki 傅昌瑞 Jtravis B Russett 戴璞 Irmgard Reiter Rasmus Palmqvist 覃立超 谢新宇 《建筑技艺》2011,(Z3):91-93
重庆是中国最年轻的直辖市,城市规划建设大有可为,完全有条件建成一个大家公认的宜居城市,一个环境优美的城市,一个交通顺畅的城市,甚至变成一个森林城市。一个有希望、有活力的地方,要敢于设想和设计自己的美好未来。——薄熙来(重庆市长) 相似文献
177.
de Adana F.S. Diego I.G. Blanco O.G. Lozano P. Catedra M.F. 《Antennas and Propagation, IEEE Transactions on》2004,52(12):3295-3303
A method to compute the monostatic radar cross section (RCS) of complex bodies modeled by nonuniform rational B-spline (NURBS) surfaces is presented. The bodies can be covered by any kind of radar absorbing material (RAM) with electric and/or magnetic losses. Physical optics (PO) is used to obtain the scattered field of each surface. Fresnel coefficients are included in the stationary phase method (SPM) in order to take into account the effect of the RAM material. The contribution of diffraction by edges and double effects is also considered, improving the results of the PO approach. The diffraction is computed by the equivalent current method (ECM). A combination of geometrical optics (GO) with PO and ECM is used for the double reflection and double interaction between edges and surfaces respectively. Some simple cases are shown to validate the proposed method. The reliability of the method to analyzing the effect of covering a realistic target with RAM is also illustrated. 相似文献
178.
Ana Morales-Rodríguez Diego Gómez-García Carmen García-Gañán Eugenio Zapata-Solvas Arturo Domínguez-Rodríguez 《Journal of Materials Science》2006,41(16):5190-5193
High temperature creep of a metal–ceramic composite consisted of yttria tetragonal zirconia polycrystals (YTZP) with a certain
amount of nickel grains (Ni–YTZP, 2.5% vol.) has been studied. The average grain size of YTZP grains was 0.20 μm, whereas
that of the Ni grains was 50–70 nm. This work reports the mechanical response under creep of such composite materials. It
is found that the activation energy for creep is significantly higher than that reported in similar systems with much larger
nickel grains. This fact has been explained in terms of the chemical nature of the metal–ceramic interfaces. 相似文献
179.
Diego T. Santos Juliana Q. Albarelli Kieran Joyce Michael Oelgemöller 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(7):1026-1030
BACKGROUND: Green chemistry, also known as sustainable chemistry, refers to environmentally friendly chemicals and processes that result in reduced waste, elimination of costly end‐of‐the‐pipe treatments; safer products, and reduced use of energy and resources. In this context this study aims to evaluate a novel green sensitizer support for photochemistry use. For this propose, Rose Bengal (RB) and juglone production were chosen as a model sensitizer and a model photoreaction, respectively. RESULTS: The results showed that the RB‐alginate beads prepared using a solution of 20% CaCl2 had better stability in the solvent t‐amyl alcohol. Comparing all the immobilized systems a larger reaction yield (57.5%) was obtained when the proportion of the beads in the photoreactor flask was 5% (v/v). Although when using suspended RB the reaction yield was better (62%) the environmental friendly attributes and economical advantages of immobilized systems overcome it. CONCLUSIONS: The potentiality of this new kind of sensitizer immobilization was demonstrated and a mechanism based on immobilization of cells was proposed. Furthermore the use of this novel green support presents a greater efficiency and potentially lower costs than the commercial supported RB Sensitox. Copyright © 2009 Society of Chemical Industry 相似文献
180.