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81.
Clotilde LM Bernard C Sequera DE Karmali A Fusellier A Carter JM 《Journal of laboratory automation》2012,17(4):309-314
Conventional enzyme-linked immunosorbent assay (ELISA) is a gold standard for screening antibodies and testing for protein or antigen presence. A significant limitation of this assay resides in the fact that only one analyte can be assessed per microplate well. Here, we describe and investigate a new technology consisting of an automated ELISA system in which up to 10 analytes can be measured within one single well, thus improving productivity, accuracy, and repeatability by reducing the amount of human labor required. Another strength of the platform is that a user can load any necessary sets/subsets of beads to perform required assays, with improved flexibility compared to manufactured-loaded arrays for multiplex analysis. We also demonstrate that this system can be used to determine the pathogenicity (i.e., presence of Shiga toxins) and serotype (i.e., Escherichia coli O157) of E. coli isolates. 相似文献
82.
83.
The sulfidation behavior of Fe-Nb alloys containing up to 30 w/o Nb was studied over the range of 600–900°C in 0.01 aim. S2 vapor. All alloys were two-phase, consisting of an Fe-rich solid solution and Fe2Nb, and followed the parabolic rate law at all temperatures. Scales consisted of two layers-an outer layer of FeS and an inner, complex layer which contained some FeS, FeNb2S4 (possibly some FeNb3S6), NbS2, and intermetallic particles which were either completely or only partially sulfidized. Platinum markers were located always at the interface between the two layers, which corresponded to the original metal surface. Activation energies were 18±3 kcal/mol in close agreement with the 19.8 reported for pure iron. The sulfidation rate decreased markedly with increasing Nb content of the alloys. The decrease is attributed to increasing amounts of Fe2Nb with increasing Nb, the net effect being that the diffusion path for outward iron diffusion through the inner layer is reduced as the Nb content increases. An analysis of the structure of NbS2 reveals that it is easily intercalated with Fe between loosely bonded layers of S-Nb-S. The S-Nb-S layers are covalently bonded which results in very low diffusivities of either S or Nb in pure NbS2. Although intercalated Fe tends to change the Van der Waal's type bonding between layers to more ionic or covalent, Fe diffuses readily between the layers in NbS2. Intercalation of Fe also increases the concentration of sulfur defects in NbS2, which in turn increases the diffusivity of sulfur. Nb was observed to be immobile. Thus, it is thought that either outward iron diffusion or inward sulfur diffusion in the inner layer is the rate-controlling step, in spite of the close agreement of activation energies with that of the sulfidation of pure iron. 相似文献
84.
Graham M. Carter John L. Henshall Robert M. Hooper 《Journal of the American Ceramic Society》1988,71(5):270-C
Indentation creep of yttria- and calcia-fully-stabilized single-crystal zirconia has been observed at room temperature. The Knoop hardnesses decreased by 15% and 12% of their conventional short-time values, respectively, for indentation times of 100000 s. 相似文献
85.
The proton magnetic resonance spectra of isomeric triglycerides of isovaleric and palmitic acids in the presence of the downfield
and upfield chemical shift reagents Eu(fod)3 and Pr(fod)3 were studied. The resonance profiles of the γ-protons on the isovaleroyl chains are distinctive for each of the four possible
triglyceride isomers at low shift reagent/triglyceride ratios. With either reagent, the well defined γ-methyl isovalerate
doublets can be used to identify 2-isovaleroyl and 1,3-isovaleroyl structures and to analyze isomeric mixtures. This technique
will be useful for positional analysis of natural cetacean triglycerides containing isovaleric acid. 相似文献
86.
For Tanzanian soils dominant in hydrous oxides of iron and amorphous ferri-alumino silicate, a 48-hour (hr) mixing period with the sulphate (SO4) solution was adequate for a near-equilibrium condition. Although differing in their SO4 sorption capacity, all the soils sorbed SO4 at or beyond 1µg ml–1 sulphur (S) concentration in the supernatant. Hydroxyl (OH) ions were displaced during SO4 sorption as indicated by a significant positive correlation between the amount of sorbed SO4 and the difference in pH values determined in 0.1N K2 SO4 and 0.1N KCl, i.e. the dpH values.In a greenhouse experiment, alfalfa was grown on eight soils at six adjusted S concentrations. Sulphur deficiency symptoms appeared in the control pots of those soils which were low in native sorbed SO4, SO4 sorption capacity and initial soil solution S concentration. Sulphur fertilization increased dry matter (DM) yield as well as response to applied S. The external S concentration, i.e. adjusted S concentration required for 95% of the maximum DM yield, ranged from 0.8 to 8.2µg S ml–1 with values less than 2.0 on most of the soils. The external S concentration decreased hyperbolically as the SO4 sorption capacity of the soils increased. The total amount of fertilizer S required to obtain the external S concentration in solution, and at the same time satisfy the SO4 sorption capacity of the soil at the external S concentration (determined from the sorption isotherm) was defined as the external S requirement for the specified yield level of alfalfa. The external S requirement for 95% of the maximum yield of alfalfa varied from soil to soil due to differences in their capacity and intensity for S nutrition.Part of a thesis by the senior author for the MSc (Agric) degree of the University of Dar es Salaam 相似文献
87.
88.
Hualong Li Emilie Hsu Jerzy Szpunar Ravi Verma Jon. T. Carter 《Journal of Materials Engineering and Performance》2007,16(3):321-326
In order to determine the deformation modes in AZ31 magnesium alloy at room temperature, computer simulations of deformation
texture development and calculation of formability have been carried out. The simulation results were compared with the measured
texture results. Based on agreement between the experiments and simulations the active deformation modes were determined.
A Visco Plastic Self Consistent model was employed for the simulation of plastic deformation. Simulations and experiments
were performed for different initial textures. The goal of the study was to develop the understanding of deformation texture
evolution and its effects on mechanical properties of magnesium, with an ultimate goal of improving room temperature formability
of magnesium alloys.
This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati,
OH, October 15-19, 2006. 相似文献
89.
Richmond VL Rayson MP Wilkinson DM Carter JM Blacker SD Nevill A Ross JD Moore S 《Ergonomics》2008,51(6):935-946
Since 2002, the Royal Air Force (RAF) has been working towards developing role-related physical tests for use as an operational fitness test (OFT). The purpose of this study was to establish reliability of the OFT (comprising four tests), investigate gym-based tests as predictors of performance and establish performance standards. Fifty-eight RAF personnel performed the OFT on three occasions. A separate cohort carried out fitness and anthropometric tests before performing the OFT, by way of establishing performance predictors. Documented evidence and views of an expert panel were used to determine OFT standards. Reliability ranged from moderate to good for three tests, with one test (Dig) showing poor reliability. The 95% limits of agreement for the prediction models ranged from good to poor (6.7-34.2%). The prediction models were not sufficiently accurate to estimate confidently OFT performance, but could be used as a guide to quantify likely outcome and training needs. 相似文献
90.
This study investigated the physiological responses and limitations to a simulated search and rescue scenario in a high-rise building under ambient conditions. Sixteen firefighters performed the scenario under four conditions: standard duration breathing apparatus (SDBA) and 45 mm hose; extended duration breathing apparatus (EDBA) and 45 mm hose; SDBA and 70 mm hose; EDBA and 70 mm hose. Core temperature, skin temperature and heart rate were monitored. In four of 32 trials the casualty was rescued; the remainder of the trials were terminated for safety, high core temperature or shortage of air. Final core temperature and heart rate were higher in the EDBA (39.1 degrees C; 72% heart rate reserve (HRR)) than SDBA conditions (38.6 degrees C; 67%HRR). No differences were observed between hose sizes. The scenario proved too onerous to complete successfully in the majority of cases. Replacing SDBA with EDBA eliminates air supply as a limiting factor, but brings with it challenges of managing thermal strain. 相似文献