331 research outputs found
Performance of VIDEBAS in an operational environment
VIDEBAS is a relational database management system in which a database consists of two parts, namely a âreal-onlyâ and an âupdateâ part. The first part remains unmodified until the next reorganization and exploits redundancy to achieve fast access to data. A prototype of VIDEBAS has been built. In this paper a performance comparison between this relational system and a DBTG-system (UDS) is made. The used external memory and the number of page accesses to retrieve and update tuples is estimated. Although it is commonly assumed that in an operational environment relational systems are slower than network systems the opposite appears. On the other hand UDS needs less external memory
A study of long-term potentiation in transgenic mice over-expressing mutant forms of both amyloid precursor protein and presenilin-1
RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.Abstract Synaptic transmission and long-term potentiation (LTP) in the CA1 region of hippocampal slices have been studied during ageing of a double transgenic mouse strain relevant to early-onset familial Alzheimer's disease (AD). This strain, which over-expresses both the 695 amino acid isoform of human amyloid precursor protein (APP) with K670N and M671L mutations and presenilin 1 with the A246E mutation, has accelerated amyloidosis and plaque formation. There was a decrease in synaptic transmission in both wildtype and transgenic mice between 2 and 9 months of age. However, preparing slices from 14 month old animals in kynurenic acid (1 mM) counteracted this age-related deficit. Basal transmission and paired-pulse facilitation was similar between the two groups at all ages (2, 6, 9 and 14 months) tested. Similarly, at all ages LTP, induced either by theta burst stimulation or by multiple tetani, was normal. These data show that a prolonged, substantially elevated level of Aβ are not sufficient to cause deficits in the induction or expression of LTP in the CA1 hippocampal region.Published versio
Total Glucosides of Danggui Buxue Tang Attenuate BLM-Induced Pulmonary Fibrosis via Regulating Oxidative Stress by Inhibiting NOX4
Pulmonary fibrosis (PF) is a serious chronic lung disease with unknown pathogenesis. Researches have confirmed that oxidative stress which is regulated by NADPH oxidase-4 (NOX4), a main source of reactive oxygen species (ROS), is an important molecular mechanism underlying PF. Previous studies showed that total glucosides of Danggui Buxue Tang (DBTG), an extract from a classical traditional Chinese herbal formula, Danggui Buxue Tang (DBT), attenuated bleomycin-induced PF in rats. However, the mechanisms of DBTG are still not clear. We hypothesize that DBTG attenuates PF through regulating the level of oxidative stress by inhibiting NOX4. And we found that fibrosis indexes hydroxyproline (HYP) and type I collagen (Col-I) were lower in DBTG groups compared with the model group. In addition, the expression of transforming growth factor-ÎČ1 (TGF-ÎČ1) and expression of alpha smooth muscle actin (α-SMA) were also much more decreased than the model group. For oxidative stress indicators, DBTG blunted the decrease of superoxide dismutase (SOD) activity, total antioxidant capacity (T-AOC), and the increase in malondialdehyde (MDA), 8-iso-prostaglandin in lung homogenates. Treatment with DBTG restrained the expression of NOX4 compared to the model group. Present study confirms that DBTG inhibits BLM-induced PF by modulating the level of oxidative stress via suppressing NOX4
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Learning from AI : new trends in database technology
Recently some researchers in the areas of database data modelling and knowledge representations in artificial intelligence have recognized that they share many common goals. In this survey paper we show the relationship between database and artificial intelligence research. We show that there has been a tendency for data models to incorporate more modelling techniques developed for knowledge representations in artificial intelligence as the desire to incorporate more application oriented semantics, user friendliness, and flexibility has increased. Increasing the semantics of the representation is the key to capturing the "reality" of the database environment, increasing user friendliness, and facilitating the support of multiple, possibly conflicting, user views of the information contained in a database
Three Denerations of DBMS
This paper describes the evolution of data base technology from early computing to the sophisticated systems of today. It presents an overview of the most popular data base management systems architectures such as hierarchical, network, relational and object-oriented. The last section of this paper presents a view of the factors that will influence the future of data base technology
Nineteen sixties history of data base management
Data base management evolved during the sixties and seventies. The evolution period was protracted. Many driving forces impacted the evolution and it is the aim of this paper to analyze these driving forces (some technical and some political) and to discuss the impact of each. The driving forces are identified as follows: higher level languages, generalization of software, non-procedural approach, program maintenance, recognition of different levels of data definition, direct access storage, and relational theory.2nd IFIP Conference on the History of Computing and EducationRed de Universidades con Carreras en InformĂĄtica (RedUNCI
Nineteen sixties history of data base management
Data base management evolved during the sixties and seventies. The evolution period was protracted. Many driving forces impacted the evolution and it is the aim of this paper to analyze these driving forces (some technical and some political) and to discuss the impact of each. The driving forces are identified as follows: higher level languages, generalization of software, non-procedural approach, program maintenance, recognition of different levels of data definition, direct access storage, and relational theory.2nd IFIP Conference on the History of Computing and EducationRed de Universidades con Carreras en InformĂĄtica (RedUNCI
Query processing in distributed heterogeneous databases
"December 1981"Bibliography: leaf [1]"Contract ONR/N00014-77-C-0532"Kuan-Tsae Huang, Wilbur B. Davenport, Jr
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