774 research outputs found
The ISIS project: Fault-tolerance in large distributed systems
The semi-annual status report covers activities of the ISIS project during the second half of 1989. The project had several independent objectives: (1) At the level of the ISIS Toolkit, ISIS release V2.0 was completed, containing bypass communication protocols. Performance of the system is greatly enhanced by this change, but the initial software release is limited in some respects. (2) The Meta project focused on the definition of the Lomita programming language for specifying rules that monitor sensors for conditions of interest and triggering appropriate reactions. This design was completed, and implementation of Lomita is underway on the Meta 2.0 platform. (3) The Deceit file system effort completed a prototype. It is planned to make Deceit available for use in two hospital information systems. (4) A long-haul communication subsystem project was completed and can be used as part of ISIS. This effort resulted in tools for linking ISIS systems on different LANs together over long-haul communications lines. (5) Magic Lantern, a graphical tool for building application monitoring and control interfaces, is included as part of the general ISIS releases
Programming your way out of the past: ISIS and the META Project
The ISIS distributed programming system and the META Project are described. The ISIS programming toolkit is an aid to low-level programming that makes it easy to build fault-tolerant distributed applications that exploit replication and concurrent execution. The META Project is reexamining high-level mechanisms such as the filesystem, shell language, and administration tools in distributed systems
Tools for distributed application management
Distributed application management consists of monitoring and controlling an application as it executes in a distributed environment. It encompasses such activities as configuration, initialization, performance monitoring, resource scheduling, and failure response. The Meta system (a collection of tools for constructing distributed application management software) is described. Meta provides the mechanism, while the programmer specifies the policy for application management. The policy is manifested as a control program which is a soft real-time reactive program. The underlying application is instrumented with a variety of built-in and user-defined sensors and actuators. These define the interface between the control program and the application. The control program also has access to a database describing the structure of the application and the characteristics of its environment. Some of the more difficult problems for application management occur when preexisting, nondistributed programs are integrated into a distributed application for which they may not have been intended. Meta allows management functions to be retrofitted to such programs with a minimum of effort
Tools for distributed application management
Distributed application management consists of monitoring and controlling an application as it executes in a distributed environment. It encompasses such activities as configuration, initialization, performance monitoring, resource scheduling, and failure response. The Meta system is described: a collection of tools for constructing distributed application management software. Meta provides the mechanism, while the programmer specifies the policy for application management. The policy is manifested as a control program which is a soft real time reactive program. The underlying application is instrumented with a variety of built-in and user defined sensors and actuators. These define the interface between the control program and the application. The control program also has access to a database describing the structure of the application and the characteristics of its environment. Some of the more difficult problems for application management occur when pre-existing, nondistributed programs are integrated into a distributed application for which they may not have been intended. Meta allows management functions to be retrofitted to such programs with a minimum of effort
The Isis project: Fault-tolerance in large distributed systems
This final status report covers activities of the Isis project during the first half of 1992. During the report period, the Isis effort has achieved a major milestone in its effort to redesign and reimplement the Isis system using Mach and Chorus as target operating system environments. In addition, we completed a number of publications that address issues raised in our prior work; some of these have recently appeared in print, while others are now being considered for publication in a variety of journals and conferences
Curcumin as scaffold for drug discovery against neurodegenerative diseases
Neurodegenerative diseases (NDs) are one of major public health problems and their impact is continuously growing. Curcumin has been proposed for the treatment of several of these pathologies, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) due to the ability of this molecule to reduce inflammation and aggregation of involved proteins. Nevertheless, the poor metabolic stability and bioavailability of curcumin reduce the possibilities of its practical use. For these reasons, many curcumin derivatives were synthetized in order to overcome some limitations. In this review will be highlighted recent results on modification of curcumin scaffold in the search of new effective therapeutic agents against NDs, with particular emphasis on AD
Stress/rest myocardial perfusion abnormalities by gated SPECT: still the best predistor of cardiac events in stable ischemic heart disease
Obesity and bone loss at menopause: The role of sclerostin
Background. Peripheral fat tissue is known to positively influence bone health. However, evidence exists that the risk of non-vertebral fractures can be increased in postmenopausal women with obesity as compared to healthy controls. The role of sclerostin, the SOST gene protein product, and body composition in this condition is unknown. Methods. We studied 28 severely obese premenopausal (age, 44.7 \ub1 3.9 years; BMI, 46.0 \ub1 4.2 kg/m2 ) and 28 BMI-matched post-menopausal women (age, 55.5 \ub1 3.8 years; BMI, 46.1 \ub1 4.8 kg/m2 ) thorough analysis of bone density (BMD) and body composition by dual X-ray absorptiometry (DXA), bone turnover markers, sclerostin serum concentration, glucose metabolism, and a panel of hormones relating to bone health. Results. Postmenopausal women harbored increased levels of the bone turnover markers CTX and NTX, while sclerostin levels were non-significantly higher as compared to premenopausal women. There were no differences in somatotroph, thyroid and adrenal hormone across menopause. Values of lumbar spine BMD were comparable between groups. By contrast, menopause was associated with lower BMD values at the hip (p < 0.001), femoral neck (p < 0.0001), and total skeleton (p < 0.005). In multivariate regression analysis, sclerostin was the strongest predictor of lumbar spine BMD (p < 0.01), while menopausal status significantly predicted BMD at total hip (p < 0.01), femoral neck (p < 0.001) and total body (p < 0.05). Finally, lean body mass emerged as the strongest predictor of total body BMD (p < 0.01). Conclusions. Our findings suggest a protective effect of obesity on lumbar spine and total body BMD at menopause possibly through mechanisms relating to lean body mass. Given the mild difference in sclerostin levels between pre-and postmenopausal women, its potential actions in obesity require further investigation
Synthesis of oxazolidinones from N-aryl-carbamate and epichlorohydrin under mild conditions
The reaction conditions for an enantiospecific synthesis of various N-aryl-oxazolidinones from N-aryl-carbamates and (R) or (S) epichlorohydrin were optimized. The N-aryl-oxazolidinones were applied to the synthesis of compounds of biological interest such as DuP 721, toloxatone and a linezolid analogue
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