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991.
992.
Georgia Ouzounidou Kalliope K. Papadopoulou Maria Asfi Ioanna Mirtziou Fragiskos Gaitis 《International Journal of Food Science & Technology》2013,48(8):1610-1617
Four different chemical treatments, GA3, 1‐MCP, essential oils and nano‐Cu, were applied immediately after harvest to Petroselinum crispum (Mill) plants. The efficacy of the above chemicals on shelf life extension of parsley stored at 5 °C and 20 °C was determined by analysing physiological and biochemical factors that determine quality standards of storage fresh parsley. Nonsprayed parsley revealed the highest loss of weight, ascorbic acid, pigments and an enhancement of CO2 production and lipid peroxidation at 5 °C and 20 °C of storage. Nano‐Cu was more effective for delaying weight loss and revealed a better storage capacity. GA3, 1‐MCP and essential oils sprays were more effective in ascorbic acid retention at 20 °C than at 5 °C, whereas all substances protect samples from lipid peroxidation. Essential oils were more clearly inhibitory towards both total viable counts and yeast infection. Our results suggest that GA3, 1‐MCP, essential oils and Nano‐Cu exert their function through different mechanisms during ripening and could provide an effective and complementary means for maintaining high‐quality parsley leaves after harvest. 相似文献
993.
Martha Lomeli Luisa Maria Flores-Velez Imelda Esparza Roberto Torres Octavio Domínguez 《Journal of the American Ceramic Society》2009,92(7):1526-1533
The present work represents preliminary results concerning the effect of nanometric CaF2 particles on the sintering behavior of kaolin. The nanoparticles were synthesized using aqueous solutions of CaCl2 dissolved with an organic dispersant and HF. The morphology and particle size of the obtained nanoparticles were square-like, having a mean length of 25 nm. Kaolin was mixed with different amounts of nanometric CaF2 (from 0.625 to 5.0 wt%) and the mixtures were milled, pressed, and sintered. From sintering experiments, it was observed that additions of CaF2 nanoparticles in kaolin clay could shift the phase transition temperatures to lower values. Specifically, the densification temperature could be reduced by almost 150°C when 2.5 wt% of CaF2 was incorporated. Besides, adding 1.25% of nanometric CaF2 can achieve that compressive strength augments from 125 to 185 MPa in kaolin samples sintered at 1200°C, meaning an improvement of 40% in the properties of the final material. 相似文献
994.
Claudia F. Galinha Gilda Carvalho Carla A. M. Portugal Giuseppe Guglielmi Maria A. M. Reis João G. Crespo 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(7):985-992
BACKGROUND: The use of two‐dimensional (2D) fluorescence for monitoring complex biological systems requires careful assessment of the effect of chemical species present, which may be fluorescent and/or may interfere with the fluorescence response of target fluorophores. Given the complexity of fluorescence data (excitation emission matrices—EEMs), the challenge is how to recover the information embedded into those EEMs that can be related quantitatively with the observed performance of the biological processes under study. RESULTS: This work shows clearly that interference effects (such as quenching and inner filter effects) occur due to the presence of multiple species in complex biological media, such as natural water matrices, wastewaters and activated sludge. A statistical multivariate analysis is proposed to recover quantitative information from 2D fluorescence data, correlating EEMs with the observed performance. A selected case study is discussed, where 2D fluorescence spectra obtained from the effluent of a membrane bioreactor were compressed using PARAFAC and successfully correlated with the effluent chemical oxygen demand, using projection to latent structures modelling. CONCLUSION: This study demonstrates the potential of using 2D fluorescence spectroscopy as a status fingerprint. Additionally, it is shown how statistical multivariate data analysis can be used to correlate EEMs with selected performance parameters for monitoring of biological systems. Copyright © 2011 Society of Chemical Industry 相似文献
995.
Konstantinos Iliopoulos George Chatzikyriakos Maria DemetriouTheodora Krasia-Christoforou Stelios Couris 《Optical Materials》2011,33(8):1342-1349
The synthesis and characterization of novel micellar nanohybrids with controllable sizes consisting of palladium nanosized core and covered by well-defined poly(lauryl methacrylate)-block-poly(2-(acetoacetoxy)ethyl methacrylate) (pLauMA-b-pAEMA) diblock copolymers are reported. Their nonlinear optical (NLO) response (i.e. nonlinear refraction and absorption and the third-order susceptibility χ(3)) is also studied under 35 ps laser excitation both in the visible and in the infrared and found to be insensitive to the size of the micelles while it was found to be greatly affected by the molar fraction of the AEMA block. To the best of our knowledge it is the first time that such Pd micellar nanohybrids are synthesized and investigated towards their NLO properties. The magnitude of the nonlinear optical response of these nanohybrids renders them promising candidates for potential optoelectronic applications. 相似文献
996.
Maria Ferreira Fernanda A. R. Oliveira &Rolf Jost 《International Journal of Food Science & Technology》1999,34(1):27-32
Summary An attempt was made to reduce the microbial load of unpasteurized fresh egg white by using cross-flow microfiltration and a Tetra-Laval bactocatch installation. Cross-flow tangential microfiltration of liquid fresh egg white was not feasible as there was irreversible membrane clogging within a few minutes of operation. As membrane clogging could have been caused by ovomucin, this protein was removed from whole fresh egg white by increasing the salt strength and lowering the pH. Ovomucin-depleted egg white (ODEW) was successfully microfiltered on the same membrane. Compared to fresh egg white, ODEW had lower foaming and viscous properties, and these properties remained unchanged after bactofiltration. The reduction of microbial load was, however, relatively low. 相似文献
997.
Kristofer Fredin Erik M.J. Johansson Tobias Blom Maria Hedlund Stefan Plogmaker Hans Siegbahn Klaus Leifer Håkan Rensmo 《Synthetic Metals》2009,159(1-2):166-170
We describe a method to fill thin films of nanoporous TiO2 with solid organic hole-conducting materials and demonstrate the procedure specifically for use in the preparation of dye-sensitized solar cells. Cross-sections of the films were investigated by scanning electron microscopy and it was observed that a hot molten organic material fills pores that are 10 μm below the surface of the film. We characterized the incident photon to current conversion efficiency properties of the solid TiO2/organic dye/organic hole-conductor heterojunctions and the spectra show that the dye is still active after the melting process. 相似文献
998.
Erica Bazzan Mariaenrica Tin Alvise Casara Davide Biondini Umberto Semenzato Elisabetta Cocconcelli Elisabetta Balestro Marco Damin Claudia Maria Radu Graziella Turato Simonetta Baraldo Paolo Simioni Paolo Spagnolo Marina Saetta Manuel G. Cosio 《International journal of molecular sciences》2021,22(12)
Extracellular vesicles (EVs) are a family of particles/vesicles present in blood and body fluids, composed of phospholipid bilayers that carry a variety of molecules that can mediate cell communication, modulating crucial cell processes such as homeostasis, induction/dampening of inflammation, and promotion of repair. Their existence, initially suspected in 1946 and confirmed in 1967, spurred a sharp increase in the number of scientific publications. Paradoxically, the increasing interest for EV content and function progressively reduced the relevance for a precise nomenclature in classifying EVs, therefore leading to a confusing scientific production. The aim of this review was to analyze the evolution of the progress in the knowledge and definition of EVs over the years, with an overview of the methodologies used for the identification of the vesicles, their cell of origin, and the detection of their cargo. The MISEV 2018 guidelines for the proper recognition nomenclature and ways to study EVs are summarized. The review finishes with a “more questions than answers” chapter, in which some of the problems we still face to fully understand the EV function and potential as a diagnostic and therapeutic tool are analyzed. 相似文献
999.
立面、周边环境以及对所在街区的一系列回应,是玛丽蒂姆酒店的设计要点。这个占地约1.2万m2的酒店基地紧邻文化中心(Kulturforum)和著名的文物保护建筑贝壳屋(Shellhaus,建筑师:Emil Fahrenkamp),且距国家美术馆和波茨坦广场不远。 相似文献
1000.
This work studies how drainage of a wet foam is affected by certain characteristics of its container: diameter, wettability and shape of the walls. Drainage is registered by three simultaneous techniques: (a) electrical conductance measurements for the evolution of the local liquid fraction, (b) close-up photos for the evolution of the local bubble size distribution and (c) volumetric measurements for the evolution of the global liquid fraction in the entire container. Electrical measurements are conducted at different heights along the foam with the aid of several pairs of non-intrusive ring electrodes. Three cylindrical Plexiglas containers of different diameter are used, before and after treatment of their walls to allow tests with hydrophobic and hydrophilic walls, respectively. To resemble the shape of common industrial containers, the lower part of the largest container has a gradually reducing diameter towards its bottom. Foam decay is slower in the hydrophobic containers, this being less evident as diameter increases. Moreover, the role of diameter and shape is complex since the highest drainage rate is measured at the largest container whereas the lowest one at the medium container. The possible effect of the container walls in promoting the macroscopic rigidity of the foam structure is discussed 相似文献