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31.
An evaluation of the Spanish CSIC performance in Biotechnology, as compared with those of the French CNRS and the Italian CNR, has been carried out to determine the balance between the generation of scientific knowledge and the transfer of technology. This study shows a high scientific productivity mostly in journals with moderate impact factor, a low generation of patents and an insufficient transfer of knowledge to the Spanish companies. Other indicators confirm the existence of competitive human resources in biotechnological research producing scientific knowledge of interest for the development of patents and that cooperates successfully at European level.  相似文献   
32.
The effect of crude oil n-paraffin molecular weight distribution on wax crystallization risk was studied. Sixteen highly paraffinic crude oils from Eastern Venezuela were characterized, in terms of hydrocarbon family distribution, by High Temperature Simulate Distillation (HTSD), Gel Permeation Chromatography (GPC), and wax content. n-Paraffin chain length was correlated with crude oil cloud point and pour point. It was demonstrated that high molecular weight linear paraffins are responsible for crude oil wax precipitation. A quantitative correlation between molecular weight distribution and crude oil flowing properties was also obtained. It was found that the wider the molecular weight distribution, the lower is the wax crystallization risk. Blends of different paraffinic crude oils were prepared and their flowing properties were evaluated in comparison with the original crudes. Cloud points below the mean value were obtained. In some cases, a synergistic effect was observed (cloud points below the minimum of the two crude oils). Blends of some of these crudes with condensates afforded improvements on crude oil flow and a reduction of wax crystallization tendency (cloud point). This phenomenon can be attributed to a combination of two factors: I. increases in C24-n-paraffins, and II. a wider molecular weight distribution.  相似文献   
33.
The transport of chromium(VI) through a flat‐sheet supported liquid membrane containing Cyanex 921 as a carrier has been investigated. The permeation of the metal is investigated as a function of various experimental variables: hydrodynamic conditions, concentration of chromium(VI) and HCl in the feed phase, carrier concentration and diluent in the membrane and strippant concentration in the stripping phase. The mass transfer coefficient and the thickness of the aqueous boundary layer were calculated from the experimental data. Furthermore, the selectivity of Cyanex 921‐based flat‐sheet supported liquid membrane towards different metal ions and the behaviour of the system against other carriers are presented. Copyright © 2003 Society of Chemical Industry  相似文献   
34.
Coupling GIS with Hydrologic and Hydraulic Flood Modelling   总被引:6,自引:1,他引:5  
Geographic Information Systems (GIS) have been recognised as a powerful means to integrate and analyse data from various sources in the context of comprehensive floodplain management. As part of this comprehensive approach to floodplain management, it is very important to be able to predict the consequences of different scenarios in terms of flooded areas and associated risk. Hydrologic and hydraulic modelling plays a crucial role and there is much to gain in incorporating these modelling capabilities in GIS. This is still a rather complex task and research is being done on the full integration of these models. Interfacing between these models and GIS may be a very efficient way of overcoming the difficulties and getting very good results in terms of engineering practice. This paper presents results based on the use of Intergraph GIS coupled with Idrisi GIS. Using these two systems substantially increased the flexibility of using GIS as a tool for flood studies. A lumped (XSRAIN) and a distributed (OMEGA) hydrologic models were used to simulate flood hydrographs. The well known HEC-2 Hydraulic model was used to compute flooded areas. These models were applied in the Livramento catchment with very good results. The computation of flooded areas for different flood scenarios, and its representation in GIS, can be used in the assessment of affected property and associated damages. This is a very useful GIS-based approach to floodplain management.  相似文献   
35.
Soluble mitochondrial F1 and F1 in complex with the natural ATPase inhibitor protein (F1-IP) catalyze the spontaneous synthesis of [gamma-32P]ATP from medium [32P]phosphate and enzyme-bound ADP when incubated in media with dimethylsulfoxide (Me2SO); under these conditions, the synthesized [gamma-32P]ATP is not released into the media, it remains tightly bound to the enzymes [Gómez-Puyou, A., Tuena de Gómez-Puyou, M. & de Meis, L. (1986) Eur. J. Biochem. 159, 133-140]. Some of the characteristics of the synthesized [gamma-32P]ATP were studied in F1 and F1-IP (ATPase activities of 70 and 1-3 micromol x min(-1) x mg(-1), respectively). In Me2SO media, gamma-phosphate of synthesized ATP in F1 or F1-IP exchanges with medium phosphate. From the rates of the exchange reaction, the half-times for hydrolysis of the synthesized ATP in F1 and F1-IP were calculated: 45 min and 58 min for F1 and F1-IP, respectively. The course that synthesized [gamma-32P]ATP follows after dilution of the Me2SO synthetic mixture with aqueous buffer was determined. After dilution, the half-life of synthesized ATP in F1 was less than 1 min. In F1-IP, ATP was also hydrolyzed, but at significantly lower rates. In F1-IP, dilution also produced release of the synthesized [gamma-32P]ATP. This was assayed by the accessibility of [gamma-32P]ATP to hexokinase. About 25% of [gamma-32P]ATP synthesized in F1-IP, but not in F1, was released into the media after dilution with aqueous buffer that contained 20 mM phosphate. Release of tightly bound ATP required the binding energy of phosphate and solvation of F1-IP, however, the particular kinetics of F1-IP were also central for medium ATP synthesis in the absence of electrochemical H+ gradients.  相似文献   
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37.
BACKGROUND: Continent urinary diversion may be necessary in a range of urological abnormalities. In circumstances where the standard techniques are not possible, alternative innovative techniques may be used. METHODS: In a female patient with bladder exstrophy, a continent diversion was recommended. The appendix was not available, the ureters were not suitable and a continent stoma was fashioned from an isolated segment of colon. RESULTS: The stoma proved to be continent, although it was somewhat stenotic. However, clean intermittent catheterization maintained its patency. CONCLUSIONS: A continent catheterizable stoma may be constructed from a segment of colon. The technique may be considered when other well recognized methods are not feasible.  相似文献   
38.
It is essential to know how the immune system acts in different neurological diseases, some of them non very well known or of unknown etiology at all. It was applied Reiber and Felgenhauer's formula in 56 patients with different diseases. IgA, IgM, IgG and albumin were quantified in sera and cerebrospinal fluid by simple immunodiffusion. It was observed more frequent IgG local synthesis and IgA in this sample.  相似文献   
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