Při endoskopické operaci jednokomorového hydrocefalu se v mezikomorovém otvoru objevil blanitý lalok chorioidálního plexu, který jako záklopka střídavě ovládal průtok likvoru skrze foramen Monroe. Toto pozorování se stalo podkladem pro konstrukci korektního matematického modelu. Jeho výsledkem je originální poznatek, že pohyb likvoru má dvojí povahu: jednak pomalý pohyb průběžný a jednak mnohonásobně rychlejší kmitavý pohyb mezi horními třemi komorami: dvěma postranními a s nimi propojenou komorou třetí. Biologický význam tohoto pohybu tkví pravděpodobně v tom, že tlumí pulzové nárazy krve do mozku a zabezpečuje tak nervové soustavě optimální prostředí. Je to asi hlavní funkce likvorového prostoru hlavy.
During an endoscopic surgery for a uni-ventricular hydrocephalus, a membranous lobe of chorioidal plexus appeared within the intraventricular opening that, as a safety valve, controlled by turns the liquor flow through Monro´s foramen. This observation became the base for constructing a proper mathematical model. It resulted in the original knowledge that the liquor motion is of two different types of nature: a slow continuous motion and much faster flutter among three upper ventricles: two lateral ones and the third ventricle connected with them. Biological importance of this motion probably consists in the fact that it absorbs pulsatory rushes of blood into the brain thus securing the optimal environment for the nervous system. This may be the main function of the liquor space within the head.
- MeSH
- Humans MeSH
- Mathematics MeSH
- Cerebrovascular Circulation physiology MeSH
- Models, Theoretical MeSH
- Check Tag
- Humans MeSH
5th ed. xii, 607 s. : il., grafy ; 30 cm
Model reprezentace znalostí obsažených v lékařských doporučeních GLIKREM (GuideLInes Knowledge REpresentation Model) vychází z GLIF modelu, který byl publikován ve specifikaci GLIF3.5. GLIKREM obsahuje některé změny a rozšíření definice a implementace původního GLIF modelu. Cílem tohoto příspěvku je popis znalostního modelu GLIKREM, jeho konstrukce, implementace v XML, realizace datového rozhraní a použití výsledného modelu.
The guideline knowledge representation system (GLIKREM) is based on a GLIF model which was published in a GLIF3.5 specification. GLIKREM contains some changes and extensions of the definition and implementation of the original GLIF model. The aim of this article is to give a description of GLIKREM, its construction, its implementation in XML, a realization of the data interface and use of the result model.
- Keywords
- GLIF model,
- MeSH
- Databases, Factual MeSH
- Financing, Organized MeSH
- Information Systems standards MeSH
- Software Design MeSH
- Decision Making, Computer-Assisted MeSH
- Practice Guidelines as Topic standards MeSH
- Systems Integration MeSH
- Decision Support Systems, Clinical MeSH
- Models, Theoretical MeSH
- Information Storage and Retrieval standards MeSH
- Knowledge Bases MeSH
- Natural Language Processing MeSH
The paper presents a simplified (but not trivial) mathematical model of the interaction between the urine flow and the male urethra and bladder, respectively. Urine is assumed to be a Newtonian fluid. The flow is considered to be non-stationary, isothermal and turbulent. The urethra and bladder wall, featuring elastic properties, experience large displacements and strains. The dynamic forces are included in the urethra wall motion. When fully extended the urethra attains the shape of an axisymetric tube. An iterative method based on the uncoupled approach is developed.
Oxygen therapy is an essential treatment of premature infants suffering from hypoxemia. Normoxemia is maintained by an adjustment of the fraction of oxygen (FiO2) in the inhaled gas mixture that is set manually or automatically based on peripheral oxygen saturation (SpO2). Automatic closed-loop systems could be more successful in controlling SpO2 than traditional manual approaches. Computer models of neonatal oxygen transport have been developed as a tool for design, validation, and comparison of the automatic control algorithms. The aim of this study was to investigate and implement the time delay of oxygen delivery after a change of set FiO2 during noninvasive ventilation support to enhance an available mathematical model of neonatal oxygen transport. The time delay of oxygen delivery after the change of FiO2 during the noninvasive nasal Continuous Positive Airway Pressure (nCPAP) ventilation support and during the High Flow High Humidity Nasal Cannula (HFHHNC) ventilation support was experimentally measured using an electromechanical gas blender and a physical model of neonatal lungs. Results show the overall time delay of the change in the oxygen fraction can be divided into the baseline of delay, with a typical time delay 5.5 s for nCPAP and 6.5 s for HFHHNC s, and an exponential rising phase with a time constant about 2–3 s. A delay subsystem was implemented into the mathematical model for a more realistic performance when simulating closed-loop control of oxygenation.
- MeSH
- Time Factors MeSH
- Hypoxia therapy MeSH
- Intensive Care, Neonatal methods MeSH
- Humans MeSH
- Infant, Premature MeSH
- Infant, Newborn MeSH
- Oxygen Inhalation Therapy methods MeSH
- Computers MeSH
- Models, Theoretical MeSH
- Research MeSH
- Check Tag
- Humans MeSH
- Infant, Newborn MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
