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排序方式: 共有673条查询结果,搜索用时 281 毫秒
61.
Species identification of meat products by ELISA 总被引:4,自引:0,他引:4
Inès Giovannacci Cécile Guizard Martine Carlier Valérie Duval Jean-Luc Martin & Claude Demeulemester 《International Journal of Food Science & Technology》2004,39(8):863-867
ELISA methods used in this study are proved to detect low contents of animal species (pork, beef, sheep and poultry), even in highly processed foods. They present the advantages of being robust, cheap and easy to perform. Nevertheless, F factors, determining the threshold values of the test, need to be validated for each species. 相似文献
62.
63.
Synthesis of few-layered graphene by ion implantation of carbon in nickel thin films 总被引:1,自引:0,他引:1
Baraton L He Z Lee CS Maurice JL Cojocaru CS Gourgues-Lorenzon AF Lee YH Pribat D 《Nanotechnology》2011,22(8):085601
The synthesis of few-layered graphene is performed by ion implantation of carbon species in thin nickel films, followed by high temperature annealing and quenching. Although ion implantation enables a precise control of the carbon content and of the uniformity of the in-plane carbon concentration in the Ni films before annealing, we observe thickness non-uniformities in the synthesized graphene layers after high temperature annealing. These non-uniformities are probably induced by the heterogeneous distribution/topography of the graphene nucleation sites on the Ni surface. Taken altogether, our results indicate that the number of graphene layers on top of Ni films is controlled by the nucleation process on the Ni surface rather than by the carbon content in the Ni film. 相似文献
64.
The characterization of cord blood hemoglobin at the molecular level is a daunting challenge because hemoglobin F (HbF) and hemoglobin A (HbA) coexist in neonatal blood. We developed and validated a method using electrospray time-of-flight mass spectrometry (ES-TOF-MS) that measures, in a single analysis, relative levels of glycated and acetylated hemoglobin and allows the calculation of relative proportions of HbA, HbF(0), and HbF(1) in cord blood. Specific sections of acquired spectra were deconvoluted using a maximum entropy-based approach to true mass scale spectra. Mass precisions were less than 3 ppm with similar accuracies. Intra-interday precisions for α- and γ-chain glycation levels were 2.10%/3.72% and 2.75%/6.79%, respectively. The linearity of the α-chain glycation response was excellent (r(2) = 0.9990). We performed sample analysis on 39 cord blood specimens and found that the glycated α- and γ-chain levels were 2.27 ± 0.21% and 2.38 ± 0.29%, respectively, while the acetylated (G)γ and (A)γ-chain levels were 8.48 ± 0.53% and 7.14 ± 0.74%, respectively. We observed three types of HbF distinguishable by the intensities of γ-chain variants. Two-thirds of cord blood specimens were classified as HbF(I) with an intensity ratio (G)γ/(A)γ of 1.90 ± 0.12. For HbF(II) type (10/39 neonates), the intensity ratio of (G)γ/(A)γ was 3.71 ± 0.28. For three neonates with HbF(III), no (A)γ-chain was detected. 相似文献
65.
Sassolas B Benoît Q Flaminio R Forest D Franc J Galimberti M Lacoudre A Michel C Montorio JL Morgado N Pinard L 《Applied optics》2011,50(13):1894-1899
Gravitational-wave detectors such as Virgo and the laser interferometric gravitational-wave observatory (LIGO) use a long-baseline Michelson interferometer with Fabry-Perot cavities in the arms to search for gravitational waves. The symmetry between the two Fabry-Perot cavities is crucial to reduce the interferometer's sensitivity to the laser amplitude and frequency noise. To this purpose, the transmittance of the mirrors in both cavities should be as close as possible. This paper describes the realization and the characterization of the first twin large low-loss mirrors with transmissions differing by less than 0.01%. 相似文献
66.
A single-gene reassortant bearing the PB2 gene of the A/Ann Arbor/6/60 cold-adapted virus in the background of the A/Korea/82 (H3N2) wild-type virus is a temperature-sensitive (ts) virus with an in vitro shutoff temperature of 38 degrees C. A single mutation at amino acid (aa) at 265 (Asp-Ser) of the PB2 protein is responsible for the ts phenotype. This ts single-gene PB2 reassortant virus was serially passaged at elevated temperatures in Madin-Darby canine kidney cells to generate ts+ phenotypic revertant viruses. Four ts+ phenotypically revertant viruses were derived independently, and each possessed a shutoff temperature for replication in vitro of > 40 degrees C. Each of the four phenotypically revertant viruses replicated efficiently in the upper and lower respiratory tracts of mice and hamsters, unlike the PB2 single-gene reassortant virus, confirming that the ts phenotype was responsible for the attenuation of this virus in rodents. Mating the ts+ revertants with wild-type virus yielded ts progeny in high frequency, indicating that the loss of ts phenotype was due to a suppressor mutation which was mapped to the PA gene in each of the four independently derived ts phenotypic revertants. Nucleotide sequence analysis confirmed the absence of new mutations on the PB2 gene and the presence of predicted amino acid changes in the PA proteins of the revertant viruses. These studies suggest that single amino acid changes at aa 245 (Glu-Lys) or 347 (Asp-Asn) of the PA protein can completely suppress the ts and attenuation phenotypes specified by the Asp-Ser mutation at aa 265 of the PB2 protein of the A/Ann Arbor/6/60 cold-adapted virus. 相似文献
67.
G Battaglia F Di Mario S Vigneri F Vianello ME Benvenuti PM Donisi V Stracca-Pansa M Pasquino 《Canadian Metallurgical Quarterly》1998,30(4):370-374
BACKGROUND: Helicobacter pylori eradication therapy can be unsuccessful in 5 to 20% of patients. AIM: To investigate the validity of a strategy using triple therapies for the retreatment of patients with eradication failure, avoiding retreatment with antibiotics prone to induce resistance after use in the first treatment. PATIENTS AND METHODS: From a consecutive sampling of 108 patients still Helicobacter pylori-positive after a first course of antibiotic-based treatment, 74 (68.5%) agreed to a second course of triple therapy. Group 1 (N = 17): treatment failures on an imidazole (1)-based therapy were retreated with clarithromycin (C)-based regimen; Group 2 (N = 28): failures on a C-based therapy with an I-based regimen; Group 3 (N = 7): failures on an IC-based therapy using an I-based regimen and Group 4 (N = 22): failures on a non-I/non-C based therapy with either an I-based, C-based or IC-based regimen. The presence of Helicobacter pylori was assessed by histology and the CLO-test at study entry and two months after stopping therapy. RESULTS: Nine patients were withdrawn from the study (12.2%) due to a lack of end point endoscopy. Helicobacter pylori was cured after the second course of therapy in all but seven patients [10.7% failure by Per Protocol analysis, 21.6% by Intention-To-Treat analysis]. No statistically significant differences were found between the four groups (Group 1: 92.9% PP, 76.5% ITT; Group 2: 90.9% PP, 71.4% ITT; Group 3: PP and ITT 85.7%; Group 4: PP and ITT 86.4%). Minor adverse events were experienced in nine, none of whom required withdrawal from the drug therapy. CONCLUSIONS: A second course of triple therapy with alternate antibiotics effectively eradicated Helicobacter pylori, with only very few treatment failures. This suggests that the therapeutic strategy employed may be recommended. 相似文献
68.
Walter Wildi Janusz Dominik Jean-Luc Loizeau Richard Linn Thomas Pierre-Yves Favarger Laurence Haller Antoine Perroud Christophe Peytremann 《Lakes & Reservoirs: Research and Management》2004,9(1):75-87
This paper quantifies sediment contamination by heavy metals in four reservoirs and one lake located downstream from major urban areas in Switzerland. The waterbodies include the Wettingen Reservoir (located on the Limmat River downstream from Zürich), the Klingnau Reservoir (on the lower Aare River), the Wohlen Reservoir (downstream from Berne), the Verbois Reservoir (downstream from Geneva) and Vidy Bay (Lake Geneva, city of Lausanne). For all sediment cores and contaminants, a trend is observed from high contaminant values in the lower part of the cores, decreasing to lower concentrations in the upper part of the cores. However, for each site and each element, specific features are recognized. Applying the criteria of the Swiss ordinance on soil protection, all sediment cores must be classified as contaminated by one or more contaminants and at variable levels. From these data, it is concluded that: reservoirs and lakes located downstream from major urban centres in Switzerland have accumulated significant volumes of contaminated sediments in the past, representing the largest, but not the most intensely, contaminated sites on a national scale; the main environmental risk is remobilization of the contaminants and their return to the food chain, particularly by infiltration into the groundwater; and although the processes of remobilization are identified, the conditions of occurrence and the amplitude of the processes are still poorly known. Different options of reservoir and lake sediment management also are discussed and further research topics defined. 相似文献
69.
Winicjusz Drozdowski Andrzej J. Wojtowicz Dariusz Wi
niewski Piotr Szupryczy
ski Sebastian Janus Jean-Luc Lefaucheur Zhenhui Gou 《Journal of Alloys and Compounds》2004,380(1-2):146-150
Radioluminescence and UV-excited photoluminescence spectra, photoluminescence time profiles, thermoluminescence glow curves and gamma-excited energy spectra (determining scintillation light yields) of several Lu2SiO5:Ce and Y2SiO5:Ce samples were recorded. The results are analyzed with attention focused on possible correlations between trap distributions, VUV responses, and light yields. The aspect of two distinct sites occupied by Ce3+ ions is also discussed. 相似文献
70.
Carmelo Battaglia 《电子与电脑》2004,(9):123-127
亚微米技术运用标准传输门单元 (经常出现在电子方法文献中)方法,为先进的具有悦耳铃声的新型移动电话平台提供了适合的功率控制性能。新型移动电话等电池供电设备的微控制器必须始终保持较低的功耗,必须始终需要较低的电源电压;其它半导体设备,如功率放大器和彩屏控制器,即使电源电压更高,也必须具有适当的与微控制器相一致的控制水平。 相似文献