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排序方式: 共有1299条查询结果,搜索用时 31 毫秒
991.
Rodrigues Silva C Dutra de Oliveira JE de Souza RA Silva HC 《Archivos latinoamericanos de nutrición》2005,55(1):23-27
Eleven diabetic patients: 5, type 1 and 6, type 2 received a low-fiber diet (I) during 1 week and during the next 7 days the same diet, enriched with 40 g of fiber (30.6% insoluble and 11.7% soluble components) from rice bran (II) per day. Results showed that mean fasting and postprandial serum glucose levels were reduced, but values of high fiber diet were significantly lower (p < 0.001) than that of the lower fiber diet. For all patients, the high-fiber diet increased fecal weight. This increase was due to the fiber excreted, rather than water retained. There was no relationship between the increase in fiber intake and its fecal excretion. Sucrose and raffinose were found in the bran, but not in the feces. Lactose was present in the stools of the patients receiving enriched diet. 相似文献
992.
Lemos JM Magalhães H Mendonça T Dionísio R 《IEEE transactions on bio-medical engineering》2005,52(11):1902-1911
The problem of embedding sensor fault tolerance in feedback control of neuromuscular blockade is considered. For tackling interruptions of feedback measurements, a structure based upon Bayesian inference as well as a predictive filter is proposed. This algorithm is general and can be applied to different situations. Here, it is incorporated in an adaptive automatic system for feedback control of neuromuscular blockade using continuous infusion of muscle relaxants. A significant contribution consists in the experimental clinical testing of the algorithm in patients undergoing surgery. 相似文献
993.
The most common metric for controller performance assessment is a comparison of the process output variance to that which would have been obtained if some optimal controller had been applied to the process over the same time frame. Usually this optimal controller is a minimum variance controller, as a metric based on this controller requires a minimum of process knowledge and no plant tests. While minimum variance controllers by definition contain an accurate disturbance model, industrial controllers contain a simple fixed disturbance model, which may or may not be an accurate representation of the actual disturbance. Shown in this paper is the effect that this simple disturbance model has on performance indices, and methodologies for controller performance assessment that accounts for this simple model. In addition, a performance metric for non-deadtime-compensated (i.e., PID) controllers is shown. 相似文献
994.
This is a progress report of an attempt to deconstruct the signaling network underlying cell cycle control in the mouse Y1 adrenocortical cell line, aiming to uncover ACTH growth regulatory pathways. Y1 adrenocortical tumor cells possess amplified and overexpressed c-Ki-ras proto-oncogene. Despite this oncogenic lesion, Y1 cells retain tight regulatory mechanisms of cell cycle control typified by the sequential events comprising the mitogenic response triggered by FGF2 in G0/G1-arrested Y1 cells: 1) activation of ERK1/2 and PI3K, by 5 minutes; 2) induction of c-Fos and c-Myc proteins by 2 hours; 3) induction of cyclin D1 protein by 5 hours; 4) phosphorylation of Rb protein between 6 and 8 hours; 5) onset of DNA synthesis by 8-9 hours. In this cell line, ACTH-receptor (ACTH-R) activates contradictory pathways of growth regulation. First, ACTH coordinately induces fos and jun gene families via activation of both ERK1/2 and cAMP/PKA pathways, resembling a mitogen. Second, ACTH-R triggers cAMP/PKA-mediated antimitogenic mechanisms comprised of Akt/PKB dephosphorylation/deactivation, c-Myc protein degradation, and p27(Kip1) protein induction. Induction of cyclin D1 depends on activation of both ERK1/2 and PI3K, but is not affected by ACTH action. As a consequence, ACTH antagonizes FGF2 mitogenic activity but ectopic expression of the c-Myc protein (via MycER fusion protein) is sufficient to abrogate this ACTH antagonistic effect over FGF2 mitogenic activity. Ectopic expression of both c-Myc and cyclin D1 is not sufficient to drive G0/G1-arrested Y1 cells into S phase, but when the sustained expression of these two proteins is complemented by ACTH treatment it promotes G1 phase progression and DNA synthesis initiation. In conclusion, ACTH-receptor lacks signaling potential sufficient to initiate a mitogenic response in Y1 adrenocortical cells and, therefore, cannot substitute for bona fide mitogens like FGF2. 相似文献
995.
Hugo ter Doest Alfons H. Salden Ernst-Jan Goedvolk Rob Kersemakers Dion Slijp Corien Prins 《Information & Communications Technology Law》2004,13(2):99-116
In this article, we present a solution to digital rights management (DRM) for electronic publishing and document management services provided by a third-party application service provider (ASP). We identify legal requirements that service providers have to guarantee with respect to DRM. We elaborate on related technological requirements and implement specific DRM service components compliant with the Open Digital Rights Language (ODRL) standard. Moreover, we show how digital rights of document content can be specified and subsequently enforced using ODRL. We conclude by discussing legal implications of technological innovation—for example, the conflicts that may arise between digital rights enforcement and privacy protection measures, and how it is possible to resolve them. 相似文献
996.
Giro A Bergia A Zuccheri G Bink HH Pleij CW Samorì B 《Microscopy research and technique》2004,65(4-5):235-245
Nowadays, the development of experimental procedures for the determination of the secondary structure of RNA molecules is taking advantage of the novel single-molecule probing and imaging techniques. We report a method for the mapping of the secondary structure of RNA molecules spread on a flat surface by means of the atomic force microscope. Globular domains comprising groups of RNA secondary and tertiary structure elements separated by unstructured domains can be discerned in the micrographs and their position along the molecule contour can be measured directly on unstained specimens. We have analyzed the morphology of a population of single molecules of 3' fragments of the Turnip Yellow Mosaic Virus RNA shorter than 1 kb in different temperature and electrolytic conditions. We found a satisfying agreement of the shape of the imaged structures with previously available evidence. The method we have developed can be used to map also different types of RNA molecules and has the advantage of showing the distribution of the single molecule conformations within the population. 相似文献
997.
The influence of undernutrition on the effectiveness of a dietary supplement of live lactobacillus regarding prevention and treatment of infantile diarrhoea was studied on 200 children 6 to 24m old. Children, undernourished (D) or controls (C), received for 90 days, in a blind experiment, a fermented milk providing L. Acidofilus y L. Casei (10(7)-10(8)/ml) (LB) or an equivalent amount of fluid milk (L). diarrhoea episodes were recorded and classified according duration: 1-4, 5-14 days, and protracted diarrhea (DP) those lasting beyond 14 days. Study requirements were fulfilled by 119 children: D-L: n=25; D-LB: n=32; C-L: n=27 y C-LB: n=35. Preventive aspects were evaluated through number of episodes and through their lasting the therapeutic ones. Episodes recorded were 134: 29 in D-L; 48 in D-LB; 37 in C-L and 20 in C-LB. In the D-LB group over 90% episodes were very short (1-4 days), percentage far higher to that observed in D-L and similar to C-LB. There were 12 episodes of DP, 9 D and 3 in C, all in the L groups. In conclusion, although the fermented milk prevent half episode in the controls but not in the undernourished, it was able to shorter episodes duration and prevent protracted diarrhoea irrespectively of nutritional status. Therefore, undernutrition impaired the ability of the lactobacillus supplement to prevent children diarrhoea, which implicates immune system, but not curative effects which are the result of local actions. 相似文献
998.
Gutiérrez-de-Terán H Pastor M Centeno NB Aqvist J Sanz F 《Chembiochem : a European journal of chemical biology》2004,5(6):841-849
A recent study reported a model of the human A(1) adenosine receptor and its agonist binding site, proposing two putative binding modes in the same binding site for the natural agonist, adenosine. The present work investigates the flexibility of this binding site by exhaustive exploration with the natural agonist and with three other adenosine derivatives: N6-cyclopentyladenosine (CPA), 2-chloro-N6-cyclopentyladenosine (CCPA), and 5'-N-ethylcarboxamidoadenosine (NECA). Our aim was to find a common binding mode for agonists that would explain the role in the binding process of the different substitutions allowed at the 2, N6, and 5' positions of adenosine. This problem was addressed through docking simulations, molecular dynamics studies, and estimations of the ligand-binding free energy with both the AUTODOCK scoring function and the linear interaction energy (LIE) approach. The results point to a single receptor-binding position that explains the effects of the different chemical modifications on the adenosine derivatives considered here. 相似文献
999.
Attilio Belmonte Umberto Celano Zhe Chen Janaki Radhaskrishnan Augusto Redolfi Sergiu Clima Olivier Richard Hugo Bender Gouri Sankar Kar Wilfried Vandervorst Ludovic Goux 《Nano Research》2018,11(8):4017-4025
Nonvolatile memory devices based on filamentary resistance switching (RS) areamong the frontrunners to fuel future devices and sensors of the internet of things (IoT) era. The capability of many metal-insulator-metal cells to switch between two distinctive resistive states in response to an external electrical stimulus has been demonstrated. Through years of selection, cells based on the drift of metal ions, namely conductive-bridge memory devices, have shown a wide range of applications with nanosecond switching speeds, nanometer scalability, high-density, and low power-consumption. However, for low (sub-10-μA) current operation, a critical challenge is still represented by programming variability and by the stability of the conductive filament over time. Here, by introducing the concept of reverse filament growth (RFG), we managed to control the structural reconfiguration of the conductive filament inside a memory cell with significant enhancements of each of the aforementioned properties. A first-in-class Cu-based switching device is demonstrated, with a dedicated stack that enabled us to systematically trigger RFG, thus tuning the device’s properties. Along with nanosecond switching speeds, we achieved an endurance of up to 106 cycles with a 102 read window, with outstanding disturb immunity and optimal stability of the filament over time. Furthermore, by tuning the filament’s shape, an excellent control of multi-level bit operations was achieved. Thus, this device offers high flexibility in memory applications. 相似文献
1000.