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排序方式: 共有274条查询结果,搜索用时 31 毫秒
51.
Barbora Jav?rková Martina Bla?ková Ladislav Fukal Pavel Rauch 《European Food Research and Technology》2012,234(6):1099-1104
Rapid and specific detection of Cronobacter spp. in powdered infant formula milk (IFM) is of great importance for health and safety reasons. In the present study, two rapid and specific methods, the immunochromatographic strip (ICT) and the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), were tested for the detection of Cronobacter spp. in IFM. IFM samples spiked by Cronobacter spp. were correctly detected as positive by both methods. These results were verified by the classical cultivation microbiological method (ISO/TS 22964:2006). All three methods were used for the analyses of 13 IMF samples from a local market with identical results. Only one IFM sample was found to be positive. Both tested methods considerably reduced the total detection time, to 24?h (ICT) and 46?h (MALDI-TOF MS), whereas the reference ISO/TS 22964:2006 method needs 140?h. 相似文献
52.
Improvement of insufficient fungal resistance of beech plywood for wet conditions was examined by: (1) incorporation of durable oak (Quercus robur) or black locust (Robinia pseudoacacia) surface veneers instead of beech (Fagus sylvatica) ones; (2) primordial treatment of beech surface veneers with 0.5, 1, 1.5 and 3 % solutions of fungicides DDAC, IPBC, Propiconazole and Tebuconazole; (3) additional treatment of beech plywood with the same fungicides. The anti-fungal efficiency of these three methods, applied to five-layer plywood boards glued with phenolic resin, was assessed either by decay test with two brown rot fungi (Coniophora puteana and Serpula lacrymans) and one white rot fungus (Trametes versicolor) using edge protected specimens according to modified ENV 12038, or by mould test with two microscopic fungi (Aspergillus niger and Penicillium brevi-compactum) according to modified EN 15457. The durability of beech plywood significantly increased after incorporation of black locust veneers into the surface layers, and also thanks to organic fungicides (0.5 % IPBC, Propiconazole or Tebuconazole, and 1.5 % DDAC) present in the surfaces. Other selected properties of beech plywood were sometimes influenced positively (e.g., soaking due to less permeable black locust and oak surface veneers) or negatively (e.g., shear strength due to fungicides). 相似文献
53.
Olga Leuner Jaroslav Havlik Jana Hummelova Elena Prokudina Pavel Novy Ladislav Kokoska 《Journal of the science of food and agriculture》2013,93(3):575-579
BACKGROUND: Isoflavones and coumestrol from dietary legumes are plant constituents showing multiple beneficial effects on humans. Owing to their ability to bind with mammalian estrogenic receptors and thereby intervention in several kinds of hormone‐related cancers, they have received much attention. Soybean (Glycine max) is currently the major source of isoflavonoids in human diet. However, dozens of tropical and subtropical leguminous species remain unexplored for their isoflavonoids content. RESULTS: We have analyzed 55 extracts from 41 tropical and subtropical legume species used either in human or animal diet by high‐performance liquid chromatography for the content of soy isoflavones, biochanin A, daidzein, daidzin, formononetin, genistein, genistin, sissotrin, ononin and the coumestan coumestrol. Genistein and biochanin A were the most abundant compounds. The highest content of genistein was found in aerial parts of Andira macrothyrsa, seeds of Pachyrhizus tuberosus and aerial parts of Calopogonium mucunoides (598, 250 and 184 µg g?1, respectively) and biochanin A in aerial parts of Cratylia argentea, C. mucunoides and flowers of A. macrothyrsa (76, 53 and 40 µg g?1, respectively). CONCLUSION: None of the samples tested was richer overall source of soy isoflavones and coumestrol than soybean; nevertheless several species (C. mucunoides or A. macrothyrsa) may serve as a promising source of individual compounds. © 2012 Society of Chemical Industry 相似文献
54.
Capillary absorption kinetics of concrete–ethylene glycol system was studied with respect to concrete matrix porosity and liquid viscosity. Porosity of specimens was altered by air-entraining agents and superplasticizers. Liquid which doesn’t react with cement gel was chosen for the experiment in order to study the reasons for deviation from Lucas–Washburn equation observed in concrete–water system. Viscosity of ethylene glycol changes from ~23 to 2 mPa s in the temperature range from 20 to 100 °C. The values of the capillary coefficient were determined at 20, 60 and 100 °C using Neutron Radiography and were found to be in the range from ~1.5 to 4.9 mm h?1/2. The results show that the Lucas–Washburn equation in concrete–ethylene glycol system is valid only for ~25 h, which indicates that swelling and rehydration of cement gel are not the main reasons for deviation observed in concrete–water system. 相似文献
55.
Young Richard A.; Valach Ladislav; Ball Jessica; Paseluikho Michele A.; Wong Yuk Shuen; DeVries Raymond J.; McLean Holly; Turkel Hayley 《Canadian Metallurgical Quarterly》2001,48(2):190
This study conceptualizes and investigates career-relevant parent–child conversations and other actions over time as a family project. Dyads composed of a parent and an adolescent from 20 families participated in a videotaped career-related conversation to determine a family career-development project that was subsequently monitored for a 6-month period and followed up with a 2nd videotaped conversation. On the basis of a systematic qualitative analysis, several dimensions were identified as facilitating the family career-development project, including joint goals, communication, goals-steps congruence, and individuation. These family career-development projects were organized as part of broader relationship, identity, parenting, and cultural projects that also played a decisive role in the success of the family career-development projects themselves. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
Josef Jirák Ladislav Koudelka Jaroslav Pospíšil Petr Mošner Lionel Montagne Laurent Delevoye 《Journal of Materials Science》2007,42(20):8592-8598
Glasses of the ternary system ZnO–Bi2O3–P2O5 were prepared and studied in two compositional series 50ZnO–xBi2O3–(50 − x)P2O5 and (50 − y)ZnO–yBi2O3–50P2O5. Two distinct glass-forming regions were found in the 50ZnO–xBi2O3–(50 − x)P2O5 glass series with x = 0–10 and 20–35 mol.% Bi2O3. All prepared Bi2O3-containing glasses reveal a high chemical durability. Small additions of Bi2O3 (∼5 mol.%) improve thermal stability of glasses. All glasses crystallize on heating within the temperature range of 505–583 °C.
Structural studies by Raman and 31P MAS NMR spectroscopies showed the rapid depolymerisation of phosphate chains within the first region with x = 0–15 and the presence of isolated Q0 phosphate units within the second region with x = 20–35. Raman studies showed that bismuth is incorporated in the glass structure in BiO6 units and their vibrational bands were observed within the spectral region of 350–700 cm−1. The evolution of properties and the spectroscopic data are both in accordance with a network former effect of Bi2O3. 相似文献
57.
Mirko M. Mili
Ladislav A. Novak 《International Journal of Circuit Theory and Applications》1981,9(1):15-32
A general method is presented of formulating the Lagrangian and anti-Lagrangian equations for networks consisting of non-linear RLCM (M = memristor) multiports with hybrid representation. The formulation is obtained with no restriction on the network topology. An explicit procedure is given to construct the scalar functions needed. This procedure is based on the concept of L and H functions introduced. The Brayton-Moser equations in a generalized form can be directly obtained from the anti-Lagrangian equations. From these equations, new equations of Brayton-Moser type can also be derived. The invariance property of Lagrangian and anti-Lagrangian equations under a transformation of variables is also discussed. 相似文献
58.
Telecommunication Systems - Within realization of the visions of the Internet-of-Things (IoT), Low Power Wide Area Networks (LPWANs) are undoubtedly one of the fields that attract high interest... 相似文献
59.
Markéta Zukalová Arnošt Zukal Hana Krýsová Ladislav Kavan Jan Procházka 《国际能源研究杂志》2020,44(11):9082-9092
An array of LiNi1/3Mn1/3Co1/3O2 (NMC 111) samples with a hollow-sphere morphology enabling the use of binder-free, millimeter-thick electrodes in a battery are prepared by a combination of ball milling, hydrothermal treatment and calcination. Materials are studied by powder X-ray diffraction, nitrogen adsorption measurements, X-ray fluorescence analysis, and scanning electron microscopy. Their electrochemical performance for Li+ extraction/insertion is tested by cyclic voltammetry and galvanostatic chronopotentiometry on thin-film electrodes. Optimized materials, prepared by mechanical and thermal treatment with surface areas of 7 to 10 m2 g−1, provide charge capacity values of 141 to 156 mAh g−1. The concentration of the crystalline phase in NMC 111 materials with a hollow-sphere morphology is found to be the decisive parameter for their galvanostatic cycling stability. Hollow spheres with well-developed NMC nanocrystals and a low concentration of amorphous phase in the walls, exhibiting excellent cycling stability and charge capacity in thin-film electrodes are incorporated into a NMC/graphite 3D-battery module. This 122 Ah/451 Wh 3D-battery provides 78% of theoretical capacity and 73% of theoretical energy after 10 formatting cycles. Additionally, the battery prototype exhibits stable performance over more than 200 cycles at C/10 rate. A series of analogous 3D Li accumulators, currently assembled and tested in a pilot plant, represent the first step toward large-scale production of novel 3D Li accumulator. 相似文献
60.
We consider the problem of finding a maximum subset of a given set of wires connecting two rows of terminals with fixed positions, such that no wires in the subset cross. We derive an algorithm that runs in O(p + (n ? p) ? g(p + 1)) time, where n is the number of wires given and p is the maximum number of noncrossing wires; in many practically relevant cases, e.g., when p is very high, it needs only linear time. We show how an extension of the algorithm solves the more general problem, where the positions of some terminals have some flexibility, within the same time bound. 相似文献