scholarly journals Distributed Models of Peritoneal Transport

Author(s):  
Joanna Stachowska-Pietka ◽  
Jacek Waniewski

This article describes the proposed approaches to creating distributed models that can, with given accuracy under given restrictions, replace classical physical models for construction objects. The ability to implement the proposed approaches is a consequence of the cyber-physical integration of building systems. The principles of forming the data structure of designed objects and distributed models, which make it possible to uniquely identify the elements and increase the level of detail of such a model, are presented. The data structure diagram of distributed modeling includes, among other things, the level of formation and transmission of signals about physical processes inside cyber-physical building systems. An enlarged algorithm for creating the structure of the distributed model which describes the process of developing a data structure, formalizing requirements for the parameters of a design object and its operating modes (including normal operating conditions and extreme conditions, including natural disasters) and selecting objects for a complete group that provides distributed modeling is presented. The article formulates the main approaches to the implementation of an important practical application of the cyber-physical integration of building systems - the possibility of forming distributed physical models of designed construction objects and the directions of further research are outlined.


1998 ◽  
Vol 18 (2) ◽  
pp. 188-192 ◽  
Author(s):  
Andrzej Breborowicz ◽  
Katarzyna Wieczorowska Tobis ◽  
Katarzyna Korybalska ◽  
Alicja Polubinska ◽  
Maciej Radkowski ◽  
...  

Objective To assess the effect of an inhibitor of nitric oxide synthesis [NG-nitro-L-arginine methyl ester (L-NAME)] on peritoneal transport during peritoneal dialysis (PD) and peritonitis in rats. Methods The authors studied peritoneal transport of small and large solutes, and net ultrafiltration (UF) in rats during PD with Dianeal 3.86 (Baxter, McGaw Park, IL, U.S.A.). They evaluated the effect of L-NAME used as an additive to dialysis fluid in concentrations 0.5 -5 mg/m L on peritoneal transport of small and large molecules and on transperitoneal UF. In addition, they studied the effect of L-NAME (5 mg/mL) during acute peritonitis induced by lipopolysaccharides (5 μg/mL) given intraperitoneally. Results The addition of L-NAME to dialysis fluid increased the selectivity of the peritoneum and net UF during dialysis. Lipopolysaccharides used as an additive to the dialysis fluid, together with L-NAME, did not induce changes in transperitoneal transport of small and large solutes and did not cause a significant decline in net UF. L-NAME given intraperitoneally reduced both local and systemic production of nitric oxide, which might explain its effects on peritoneal transport. Conclusions Nitric oxide is an important mediator of changes in peritoneal transport and its effect is especially significant during peritonitis.


2016 ◽  
Vol 36 (5) ◽  
pp. 555-561 ◽  
Author(s):  
Vicente Pérez-Díaz ◽  
Alfonso Pérez-Escudero ◽  
Sandra Sanz-Ballesteros ◽  
Guadalupe Rodríguez-Portela ◽  
Susana Valenciano-Martínez ◽  
...  

Background Peritoneal dialysis (PD) has limited power for liquid extraction (ultrafiltration), so fluid overload remains a major cause of treatment failure. Methods We present steady concentration peritonal dialysis (SCPD), which increases ultrafiltration of PD exchanges by maintaining a constant peritoneal glucose concentration. This is achieved by infusing 50% glucose solution at a constant rate (typically 40 mL/h) during the 4-hour dwell of a 2-L 1.36% glucose exchange. We treated 21 fluid overload episodes on 6 PD patients with high or average-high peritoneal transport characteristics who refused hemodialysis as an alternative. Each treatment consisted of a single session with 1 to 4 SCPD exchanges (as needed). Results Ultrafiltration averaged 653 ± 363 mL/4 h — twice the ultrafiltration of the peritoneal equilibration test (PET) (300 ± 251 mL/4 h, p < 0.001) and 6-fold the daily ultrafiltration (100 ± 123 mL/4 h, p < 0.001). Serum and peritoneal glucose stability and dialysis efficacy were excellent (glycemia 126 ± 25 mg/dL, peritoneal glucose 1,830 ± 365 mg/dL, D/P creatinine 0.77 ± 0.08). The treatment reversed all episodes of fluid overload, avoiding transfer to hemodialysis. Ultrafiltration was proportional to fluid overload ( p < 0.01) and inversely proportional to final peritoneal glucose concentration ( p < 0.05). Conclusion This preliminary clinical experience confirms the potential of SCPD to safely and effectively increase ultrafiltration of PD exchanges. It also shows peritoneal transport in a new dynamic context, enhancing the influence of factors unrelated to the osmotic gradient.


1989 ◽  
Vol 1 (2) ◽  
pp. 230-241 ◽  
Author(s):  
Thomas J. Anastasio ◽  
David A. Robinson

The mechanisms of eye-movement control are among the best understood in motor neurophysiology. Detailed anatomical and physiological data have paved the way for theoretical models that have unified existing knowledge and suggested further experiments. These models have generally taken the form of black-box diagrams (for example, Robinson 1981) representing the flow of hypothetical signals between idealized signal-processing blocks. They approximate overall oculomotor behavior but indicate little about how real eye-movement signals would be carried and processed by real neural networks. Neurons that combine and transmit oculomotor signals, such as those in the vestibular nucleus (VN), actually do so in a diverse, seemingly random way that would be impossible to predict from a block diagram. The purpose of this study is to use a neural-network learning scheme (Rumelhart et al. 1986) to construct parallel, distributed models of the vestibulo-oculomotor system that simulate the diversity of responses recorded experimentally from VN neurons.


SIMULATION ◽  
2012 ◽  
Vol 88 (9) ◽  
pp. 1080-1092 ◽  
Author(s):  
András Jávor ◽  
Attila Fűr

Simulation is aimed very often to solve problems of great complexity requiring – beyond using the advanced simulation software tools – platforms that enable the implementation of such software systems. In recent years the concept of cloud computing has emerged and is being applied more and more widely for solving such problems. This paper, beyond delineating the main trends of the development of distributed simulation over a grid, especially over the Internet through Web-based applications, highlights the concepts of service-based simulation system approach. This concept gives the possibility of implementing Web- or cloud agents and other ASP system compliant simulation services based on simulation standards. As a sample application, Fuzzy Web Service is demonstrated as a part of CASSANDRA 4.0 (Cognizant Adaptive Simulation System for Applications in Numerous Different Relevant Areas) that is developed by the McLeod Institute of Simulation Sciences Hungarian Center.


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