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1.
The sodium-potassium activated and magnesium dependent adenosine-5'-triphosphatase (Na(+)-K(+)/Mg(+2) ATPase EC.3.6.1.3.) activity and lipid peroxidation and early ultrastructural findings were determined in rat brain at the acute stage of ischaemia produced by permanent unilateral occlusion of the middle cerebral artery (MCA). The effects of the pretreatment with intravenous high-dose methylprednisolone (MP) on these biochemical indices and ultrastructural findings were also evaluated in the same model. The rats were divided into four groups. In group I, 10 rats were used to determine Na(+)-K(+)/Mg(+2) ATPase activity and the extent of lipid peroxidation by measuring the malondialdehyde (MDA) content and normal ultrastructural findings. In group II on 20 rats, only subtemporal craniectomy was done in order to determine the effects of the surgical procedure on these indices and findings. This group was treated intravenously with saline solution before occlusion. In group III with MCA occlusion, saline solution was administered intravenously to 20 rats in the same amount of methylprednisolone used in group IV, ten minutes before the occlusion. In Group IV, a single high-dose (30 mg/kg) of methylprednisolone was administered intravenously, ten minutes before occlusion in 20 rats. After occlusion of the middle cerebral artery, Na(+)-K(+)/Mg(+2) ATPase activity was decreased promptly in the first ten minutes in the ischaemic hemisphere and remained at a lower level than the contralateral hemispheres in the same group and the normal levels in group I, during 120 minutes of ischaemia. A single dose methylprednisolone pretreatment prohibited the inactivation of Na(+)-K(+)/Mg(+2) ATPase. On the other hand, there was significant difference in malondialdehyde content between group I and group III. Malondialdehyde levels were significantly increased following ischaemia and a non-significant increase was observed in the contralateral hemisphere. Methylprednisolone treatment significantly decreased malondialdehyde content on the side of the ischaemic hemisphere. We conclude that there is a positive relationship between membrane-bound enzyme Na(+)-K(+)/Mg(+2) ATPase activity, malondialdehyde content and early ultrastructural changes in the treated group with MP. These data suggest that the pretreatment injection of high doses (30 mg/kg) methylprednisolone contribute to the protection of the brain from ischaemia with stabilization of the cell membrane by effecting the lipid peroxidation and the activation of Na(+)-K(+)/Mg(+2) ATPase.  相似文献   
2.
On the basis of a geological - volcanological - geophysical survey, integrated with petrological and geochronological data, a structural model, including a shallow magmatic body, was defined for the Ribeira Grande area, Sao Miguel island (Azores). Two series of production tests were carried out in the Pico Vermelho 1 and Ribeira Grande 1 wells, which led to a preliminary definition of the deep fluid circulation. The data obtained from these studies were used to reconstruct a preliminary model of the Ribeira Grande geothermal field.  相似文献   
3.
Diels-Alder cycloaddition of furfural to C60 in toluene has been realised. UV-VIS, FTIR and 1H-NMR investigations suggest that the conjugated structure of furfural was changed into a non-conjugated structure in the product.  相似文献   
4.
On September 11, 2001, an airliner was intentionally crashed into the Pentagon. It struck at the first elevated slab on the west wall, and slid approximately 310?ft (94.5?m) diagonally into the building. The force of the collision demolished numerous columns and the fa?ade of the exterior wall, and induced damage to first-floor columns and the first elevated slab over an area approximately 90?ft (27.4?m) wide and 310?ft (94.5?m) long. None of the building collapsed immediately. The portion that remained standing, even after an intense fire, sustained substantial damage at the first-floor level.  相似文献   
5.
On September 11, 2001, the reinforced concrete structure of the Pentagon Building was able to resist, without collapse, the impact of a large commercial airliner despite the total loss of 26 columns and severe damage to 15 columns at the ground level. The ensuing fire and related fire-fighting activities led to the collapse of a portion of the building approximately one-half hour after the impact. In this paper, the reasons for the demonstrated toughness of the reinforced concrete structure are examined and attributed to use of spiral columns, effective splicing of reinforcing bars, strong girders, and short span lengths.  相似文献   
6.
In this paper, we study the reactive scheduling problems in a dynamic and stochastic manufacturing environment. Specifically, we develop a simulation-based scheduling system for flexible manufacturing systems. We also propose several reactive scheduling policies (i.e. when-to-schedule and how-to-schedule policies) and test their performances under various experimental conditions, processing time variations, and machine breakdowns. Moreover, we compare offline and online scheduling schemes in a dynamic manufacturing environment. The results of extensive simulation experiments indicate that the variable-time-response is better than the fixed-time-response. The full scheduling scheme generally performs better than the partial scheduling. Finally, the online scheduling is more robust to uncertainty and variations in processing times than the optimum-seeking offline scheduling. A comprehensive bibliography is also provided in the paper.  相似文献   
7.
In recent years, the interests of disassembly line have increased owing to economic reasons and the increase of environmental awareness. Effective line can provide many advantages in terms of economic aspect and it facilitates competition the companies with others. This study contributes to the relevant literature by a branch, bound and remember algorithm for disassembly line balancing problem with AND/OR precedence. The proposed exact solution method employs the memory-based dominance rule to eliminate the reduplicated sub-problems by storing all the searched sub-problems and to utilise cyclic best-first search strategy to obtain high-quality complete solutions fast. In this paper, minimising the number of stations is taken as the performance measure. The proposed methodology is tested on a set of 260 instances and compared with the mathematical model using CPLEX solver and five well-known metaheuristics. Computational results show that the proposed method is capable of obtaining the optimal solutions for all the tested instances with less than 0.1?seconds on average. Additionally, comparative study demonstrates that the proposed method is the state-of-the-art algorithm and outperforms the CPLEX solver and metaheuristics in terms of both solution quality and search speed aspects.  相似文献   
8.
In this study, a novel multi-objective optimization method based on the best effect of unique input (independent variable) values on responses (dependent variables) was proposed. The proposed method was compared with optimization using Derringer & Suich function that is still the most used. The comparison was made using the response values measured in real experiments and available in the literature. The advantages of the proposed method such as not needing the polynomial model aiming to predict the response values, no parameter selection problem, being able to offer optimum range instead of single optimum value, being suitable for use with existing experimental designs and being simple and interpretable were demonstrated as a result of comparison. It was also suggested how the proposed method will be effective according to experimental designs, and application for the users' application was presented.  相似文献   
9.
The recombinant Saccharomyces cerevisiae strain, YPB‐G, producing and secreting Bacillus subtilis α‐amylase and Aspergillus awamori glucoamylase as a fusion protein yielded efficient utilisation of starch. A segregated population balance model has been used to determine the probability of plasmid loss and plasmid copy number. The kinetics of cell growth and product (fusion protein) formation were based on a genetically structured model. The predictions were compared with the experimental observations obtained for the unstable recombinant S cerevisiae cells in a 1.5 dm?3 batch bioreactor with 30 g dm3 initial starch under non‐aerated conditions. The main advantage of the present model is that three different genetic classes were defined on the basis of the existence of plasmid and of the expression of the enzymes, ie cells containing plasmids and expressing the gene product, x1; cells containing plasmids and but not expressing the gene product, x2; and cells without plasmids, x3. It is confirmed by this model that the cells without plasmids outgrow and dominate in the fermentation medium (2.27 g dm?3 vs 0.51 g dm?3) as more and more glucose becomes available by the degradation of starch. © 2001 Society of Chemical Industry  相似文献   
10.
This paper aims to develop methods that are capable of detecting manipulation in the Istanbul Stock Exchange. We take the difference between manipulated stock’s and index’s average daily return, average daily change in trading volume and average daily volatility and used these statistics as explanatory variables. The data in post-manipulation and pre-manipulation periods are used as non-manipulated instances while the data in the manipulation period are used as manipulated instances. Test performance of classification accuracy, sensitivity and specificity statistics for Artificial Neural Networks (ANN) and Support Vector Machine (SVM) are compared with the results of discriminant analysis and logistics regression (logit). We found that the data mining techniques (ANN and SVM) are better suited to detect stock-price manipulation than multivariate statistical techniques (discriminant analysis, logistics regression) as the performances of the data mining techniques in terms of total classification accuracy and sensitivity statistics are better than those of multivariate techniques. We also found that unit change in difference between average daily return of manipulated stock and the index has the largest effect while unit change in difference between average daily change in trading volume of manipulated stock and index has the least effect on multivariate classifiers’ decision functions.  相似文献   
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