Učební texty Univerzity Karlovy v Praze
3. vydání 54 stran : ilustrace ; 30 cm
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- Učební osnovy. Vyučovací předměty. Učebnice
- NLK Obory
- fyzika, biofyzika
- NLK Publikační typ
- učebnice vysokých škol
- Publikační typ
- abstrakt z konference MeSH
- MeSH
- antioxidancia aplikace a dávkování MeSH
- experimenty na zvířatech MeSH
- financování organizované MeSH
- melatonin izolace a purifikace krev MeSH
- motorické dovednosti fyziologie účinky léků MeSH
- potkani Wistar MeSH
- stárnutí fyziologie účinky léků MeSH
- statistika jako téma MeSH
- svalová síla fyziologie účinky léků MeSH
- tloušťka kožní řasy MeSH
- vysokoúčinná kapalinová chromatografie metody přístrojové vybavení využití MeSH
- změny tělesné hmotnosti MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
Mechanical behavior of biological structures under dynamic loading generally depends on elastic as well as viscous properties of biological materials. The significance of "viscous" parameters in real situations remains to be elucidated. Behavior of rheological models consisting of a combination of inertial body and two Voigt's bodies were described mathematically with respect to inverse problem solution, and behavior in impulse and harmonic loadings was analyzed. Samples of walls of porcine and human aorta thoracica in transverse direction and samples of human bone (caput femoris, substantia compacta) were measured. Deformation responses of human skin in vivo were also measured. Values of elastic moduli of porcine aorta walls were in the interval from 10(2)kPa to 10(3) kPa, values of viscous coefficients were in the interval from 10(2) Pa.s to 10(3) Pa.s. The value of shear stress moduli of human caput femoris, substantia compacta range from 52.7 to 161.1 MPa, and viscous coefficients were in the interval from 27.3 to 98.9 kPa.s. The role of viscous coefficients is significant for relatively high loading frequencies - in our materials above 8 Hz in aorta walls and 5 Hz for bones. In bones, the viscosity reduced maximum deformation corresponding to short rectangular stress.
- MeSH
- aorta thoracica fyziologie MeSH
- biologické modely MeSH
- dospělí MeSH
- fyziologie kůže * MeSH
- kosti a kostní tkáň fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mechanický stres MeSH
- pružnost MeSH
- reologie MeSH
- senioři MeSH
- Sus scrofa MeSH
- tlak MeSH
- točivý moment MeSH
- viskozita MeSH
- zvířata MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The actual level of the true aging of an organism is characterized by its biological age. By the means of measuring the function ability of its physiological systems, it is possible to evaluate the biological age and use it as an indicator of premature aging. Inclusion of the biological age screening among the basic health precautions should offer yet another viewpoint on how to objectively measure the changes in an organism corresponding to aging. The article presents a comparison of age dependency of selected biomarkers between groups of healthy men and paraplegics. The measurement of the battery of biomarkers was run in a group of 25 healthy male adults between 36 and 54 years of age. The second group was formed by 20 paraplegics - men between 33 and 50 years of age. In spite of small size of the groups, significant differences were found in 4 of 6 biomarkers.
- MeSH
- antropometrie MeSH
- biologické markery MeSH
- dospělí MeSH
- index tělesné hmotnosti MeSH
- krevní tlak fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- paraplegie patofyziologie MeSH
- referenční hodnoty MeSH
- stárnutí fyziologie MeSH
- věkové faktory MeSH
- vitální kapacita fyziologie MeSH
- zrak fyziologie MeSH
- zrakové testy MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- srovnávací studie MeSH
The lack of exact definition of the concept of biological age (BA) is a typical feature of works concerning BA. That is why comparison of results of various published methods makes little sense and eventual proof of their optimality is impossible. Based on natural and simple presumptions, an attempt to express mathematically the supposed relation between chronological age (CA) and BA has proven to be unexpectedly fruitful. In the present paper, an optimum method of estimation of BA, which is easily applicable even in nonlinear cases, is derived. Moreover, the method allows evaluating the precision of the estimates and also offers tools for validation of presumptions of the method. A special feature of the method is that CA should be used as a standard biomarker, leading to essential improving the precision of BA-estimate and illuminating relativity of the known "paradox of biomarkers". All theoretical results of the method were fully approved by means of a special simulation program. Further, the theory and the results of the simulation have proven that many published results of BA-estimates using multiple linear regression (MLR) are very probably disserviceable because CA is typically more precise estimate of BA than estimates computed by MLR. This unpleasant conclusion also concerns methods, which use MLR as the final step after transformation of the battery of biomarkers by factor analysis or by principal component analysis.
