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891.
Biogenic amine levels and other biochemical indicators were measured to study the safety of and the loss of freshness in iced Atlantic cod. Biogenic amine content exhibited high variability during iced storage of Atlantic cod. Ornithine and lysine decarboxylase activity apparently increased at the end of the storage period. Amino acid activity was probably generated by endogenous amino acid decarboxylases of raw fish. No statistical differences were observed in the total volatile base fraction or in the ammonia or monomethylamine contents during iced storage. However, trimethylamine contents showed a significant exponential relationship with time and sensory score. Cod formed inosine as the major metabolite of IMP. The H and G indices showed a linear relationship with time and sensory score and served as good indicators of cod freshness quality. However, the K, Ki, and P indices showed a logarithmic relationship with time and sensory score. IMP, K, Ki, and P served as indicators of freshness lost during the early stages of chilled storage of cod. 相似文献
892.
Guillaume YC Perrin FX Guinchard C Nicod L Truong TT Xicluna A Millet J Thomassint M 《Analytical chemistry》2002,74(6):1217-1222
Slalom chromatography (SC) is used for the separation of large double-stranded DNA molecules. In this technique, the progression of the DNA fragments through the closed column packing follows the flow direction and is like a snake edging is way into long grass. A novel mathematical model is developed in this paper to describe this hydrodynamic phenomenon. The results obtained provided a model for the resolution between two adjacent peaks on a chromatogram. As well, a chromatographic response function was used to obtain the most efficient separation conditions for a mixture of DNA fragments with sizes higher than 15 kbp in a minimum analysis time. 相似文献
893.
Symonds C Sagnes I Garnache A Hoogland S Saint-Girons G Tropper AC Oudar JL 《Applied optics》2003,42(33):6678-6681
Continuous-wave operation, to as high as 7 degrees C, of 1.5-microm optically pumped vertical-external-cavity surface-emitting lasers is reported. The epitaxial structure, monolithically grown on InP by metal-organic chemical vapor deposition, consists of an InAlAs/GaInAlAs Bragg reflector, an InGaAs/InGaAsP active region, and an InP capping layer. The threshold incident pump intensity is <9 kW/cm2. 相似文献
894.
In this paper, we give a relatively simple though very efficient way to color the d-dimensional grid G(n1,n2,…,nd) (with ni vertices in each dimension 1?i?d), for two different types of vertex colorings: (1) acyclic coloring of graphs, in which we color the vertices such that (i) no two neighbors are assigned the same color and (ii) for any two colors i and j, the subgraph induced by the vertices colored i or j is acyclic; and (2) k-distance coloring of graphs, in which every vertex must be colored in such a way that two vertices lying at distance less than or equal to k must be assigned different colors. The minimum number of colors needed to acyclically color (respectively k-distance color) a graph G is called acyclic chromatic number of G (respectively k-distance chromatic number), and denoted a(G) (respectively χk(G)).The method we propose for coloring the d-dimensional grid in those two variants relies on the representation of the vertices of Gd(n1,…,nd) thanks to its coordinates in each dimension; this gives us upper bounds on a(Gd(n1,…,nd)) and χk(Gd(n1,…,nd)).We also give lower bounds on a(Gd(n1,…,nd)) and χk(Gd(n1,…,nd)). In particular, we give a lower bound on a(G) for any graph G; surprisingly, as far as we know this result was never mentioned before. Applied to the d-dimensional grid Gd(n1,…,nd), the lower and upper bounds for a(Gd(n1,…,nd)) match (and thus give an optimal result) when the lengths in each dimension are “sufficiently large” (more precisely, if ). If this is not the case, then these bounds differ by an additive constant at most equal to . Concerning χk(Gd(n1,…,nd)), we give exact results on its value for (1) k=2 and any d?1, and (2) d=2 and any k?1.In the case of acyclic coloring, we also apply our results to hypercubes of dimension d, Hd, which are a particular case of Gd(n1,…,nd) in which there are only 2 vertices in each dimension. In that case, the bounds we obtain differ by a multiplicative constant equal to 2. 相似文献
895.
Luc Lurton Guillaume Snakkers Claudie Roulland Bernard Galy Alain Versavaud 《Journal of the science of food and agriculture》1995,67(4):485-491
Fifteen indigenous strains of Saccharomyces cerevisiae, differentiated by their genetic polymorphism, were compared in standard conditions for their respective ability to produce volatile compounds during the alcoholic fermentation of grape must. The results were processed using analysis of variance and of principal components. They exhibited significant differences between strains, in particular for the higher alcohols, fatty acid esters, acetates or acetaldehyde. On the basis of their analytical profile, five strains were selected and compared on the pilot scale. Overall, the pilot results confirmed laboratory findings. As the strain effect appears to be determinant on the aromatic composition of wine spirits, a programme of selection based on both intraspecific molecular characterisation and chromatographic analysis is carried out to obtain specific yeast strains for high-quality spirits. 相似文献
896.
Guillaume P. Schoukens J. Pintelon R. 《IEEE transactions on instrumentation and measurement》1989,38(6):1050-1056
Although the roots of a polynomial of high order are extremely sensitive to perturbations in its coefficients, experience has demonstrated that frequency-domain estimation techniques succeed in the determination of accurate poles and zeros, even in the case of high-order transfer function models. The authors prove that this is due to the correlations among the estimated coefficients. When the result of a measurement is a set of correlated values, they conclude that it is not justifiable to use the standard deviation to determine the number of significant digits. Additional digits have to be considered in order to maintain the information enclosed in the correlations 相似文献
897.
Intra-macrophage lipid particles collected by bronchoalveolar lavage: incidence and diagnostic value
P Gratadour JM Védrinne C Guillaume MC Gagnieu J Motin 《Canadian Metallurgical Quarterly》1993,12(5):462-468
This study aimed to determine the incidence and diagnostic value of fat-laden alveolar macrophages obtained by bronchoalveolar lavage (BAL). In 128 patients, including 66 patients admitted for multiple trauma, 158 BAL were carried out. However, 41 BAL from 32 patients were excluded because of poor quality of samples (not enough macrophages, too many ciliated cells, or haemorrhage). All the patients were intubated and mechanically ventilated, having pulmonary infiltrates on the chest film. BAL samples were examined after staining with oil-red-O. They were considered to be positive when more than 5% of alveolar macrophages contained fat droplets. Among them 14 out of 47 patients (30%) without multiple trauma were positive; 7/14 had never been given any intravenous lipid infusion, and 5/14 had aspiration pneumonia (as opposed to 3/32 patients with negative BAL). Further 27 patients out of the 49 (55%) with multiple trauma were positive. Among them 10/49 had clinical evidence of fat embolism, however, only 7/10 had positive samples. All these last ten patients had been given intravenous lipid infusions. The rate of positive alveolar macrophages was correlated neither with the plasma triglyceride concentration, nor the Fracture Index Score, nor the delay between the end of the lipid infusion and the BAL. There was no significant difference in PaO2/FIO2 ratio between the patients with positive and negative BAL. Positive BAL was significantly associated with lipid infusions. The data therefore suggest that the presence of fat-laden alveolar macrophages are associated with various pathological pulmonary conditions, particularly aspiration pneumonia and lipid infusions.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
898.
Identification of linear systems captured in a feedback loop 总被引:1,自引:0,他引:1
Pintelon R. Guillaume P. Rolain Y. Verbeyst F. 《IEEE transactions on instrumentation and measurement》1992,41(6):747-754
The identification of model parameters using measured input-output data from linear systems operating in a closed loop is discussed. A frequency-domain maximum likelihood estimator which takes into account the correlation between the input and output disturbances is presented. Its properties are analyzed and illustrated by simulation examples and real measurements 相似文献
899.
We have studied by dilatometry, microscopy, X-ray and electron diffraction, the phase transformations generated by controlled cooling from 900° C of the “Mulberry” alloy (U-7.5 wt%Zr). For slow cooling rates, three types of decomposition of the 7 phase appear successively: (i) Between 600°C and 550°C, grain boundaries and inclusion serve as nucleation sites for a cellular reaction, ; (ii) between 550°C and 400°C, a continuous transformation of the matrix generates an a phase in the form of Widmanstätten plates, and (iii) below 400°C, the γ phase gives rise to an α″ phase which has an ultrafine structure only imperfectly resolved by TEM. On rapid cooling, a tetragonal phase, γ0, appears. Quenching generates the γS phase derived from γ, with a structure crystallizing in 143m which has been described by YakeL The various methods of investigation used have allowed us to obtain heating and cooling curves of the alloy and thus to determine phase fields. In general terms, the structures formed are similar to those obtained by isothermal annealing below 600° C. Only the γS phase has useful mechanical properties, notably good ductibility. The other phases are characterised by extreme brittleness. 相似文献
900.