Physiological Models

Two different Calanus finmarchicus (Gunnerus) cohorts originating from 60°N (Bergen) and 69°N (Tromsø) were investigated in equal environmental conditions to study their different physiological responses to the same environment. A two-plus-two-bag mesocosm study was carried out between March and July 1998, in Håkøybotn, Tromsø, in order to determine development and mortality rates of the two parallel cohorts of C. finmarchicus. For practical reasons, the cohort from Bergen was incubated 10 days earlier than the Tromsø cohort. Consequently, they were exposed to elevated food conditions as compared to the Tromsø cohort. A high initial mortality among the Bergen cohort could clearly be ascribed, by genetic discrimination, to "contamination" with C. helgolandicus. After this initial mass mortality, the mortality was constantly 0.03–0.04 day−1. In cohorts starting from naupliar stage I, there was no significant difference in development or growth, the median development time (NI–CIV) differing by only 7 days (~6%). The difference in development time can be explained to a large extent (~4 days) by temperature differences. This is substantiated with model simulations using a physiological model developed for C. finmarchicus. There was a time lag in incubation between the two cohorts, resulting in elevated temperature during incubation of the Tromsø cohort. A fraction of both cohorts differentiated sexually at stage CV, with males differentiating before females. Females from both cohorts produced eggs, but specific egg production differed significantly (P>0.001, t-test). This was supported by elevated RNA:DNA ratio in females from the Bergen cohort. Both cohorts demonstrated quite similar development and physiological growth rates and, consequently, are considered to belong to the same genetic population inhabiting the Norwegian Shelf. The study demonstrates that C. finmarchicus is capable of adaptation to changes in environment and, thereby, demonstrates a significant physiological plasticity.

This paper describes a knowledge based system employing certain expert system rules to detect different kind of eye diseases found in Malaysia. The types of eye diseases that can be detected with this system are allergic or infectious conjunctivitis, secondary and senile cataract, open angle glaucoma and acute glaucoma, keratitis and dry eyes syndrome. These are the most frequent eye diseases infecting the Malaysian population. The project was designed and programmed via the object-oriented expert system shell software, EXSYS. Expert rules were developed based on the symptoms of each type of the eye diseases, and they were presented using a tree graph forward chaining with depth search first method. In order to enhance user interaction with the system, graphical user interfaces were employed. Previously, several similar works have been published, but they are limited to detecting a single disease and also required expert medical officer to operate. The expert system described in this paper is able to detect and gives early diagnosis of five types of eye diseases; inclusive of senile, secondary, open angle, acute, allergic and infections.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=949629&tag=1

This paper describes the development of nonlinear autoregressive moving average with exogenous input (NARMAX) models in diagnosing dengue infection. The developed system bases its prediction solely on the bioelectrical impedance parameters and physiological data. Three different NARMAX model order selection criteria namely FPE, AIC and Lipschitz have been evaluated and analyzed. This model is divided two approaches which are unregularized approach and regularized approach. The results show that using Lipschitz number with regularized approach yield better accuracy by 88.40% to diagnose the dengue infections disease. Furthermore, this analysis show that the NARMAX model yield better accuracy as compared to autoregressive moving average with exogenous input (ARMAX) model in diagnosis intelligent system based on the input variables namely gender, weight, vomiting, reactance and the day of the fever as recommended by the outcomes of statistical tests with 76.70% accuracy. © ICROS.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4406927

The intraspecies uncertainty factor (UF(HH)=10x) is used in the determination of the reference dose or reference concentration and accounts for the pharmacokinetic and pharmacodynamic heterogeneity within the human population. The Food Quality Protection Act of 1996 mandated the use of an additional uncertainty factor (UF(HC)=10x) to take into account potential pre- and postnatal toxicity and lack of completeness of the data with respect to exposure and toxicity to children. There is no conclusive experimental or theoretical justification to support or refute the magnitude of the UF(HH) and UF(HC) nor any conclusive evidence to suggest that a factor of 100 is needed to account for intrahuman variability. This study presents a new chemical-specific method for estimating the pharmacokinetic (PK) component of the interspecies uncertainty factor (UF(HH-PK) and UF(HC-PK)) for volatile organic compounds (VOCs). The approach utilizes validated physiological-based pharmacokinetic (PBPK) mod...

In this study, the mechanical responses for the knee joint model in various degrees of flexion and loadings during gait are investigated. Three gait phases consisting of heel strike (HS) (5.5), single limb stance (SLS) (15.5), and toe-off (TO) (4.5) are considered to represent the gait cycle while simulated loading conditions applied for each phase are 2.25 times body weight (BW), 1.85 times BW, and 3.5 times BW, respectively, where the BW is 495 N. The knee images are imported from a computerized tomography (CT) scan to Mimics version 13.1 software for smoothing and constructing to the three-dimensional (3D) model of the tibio-femoral (TF) joint. Finite element analysis (FEA) using the ABAQUS v.6.7 software was performed to simulate the biomechanical patterns of the tibiofemoral (TF) joint. The knee joint is modeled with femur condyles, tibia plateau, and menisci attachment. The contact pressure toward these 3 components is investigated at each medial and lateral compartment of the joint parts. The simulating results are verified and compared with well-known results in the literatures, which showed that contact pressure behaved much greater on the medial compartments than on the lateral compartments throughout the phases. Meanwhile, it was found that the peak contact pressure occurred during TO. © 2012 IEEE.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6178951&tag=1

Various and disparate technical disciplines have identified a growing need for tools to predict human thermal and thermoregulatory responses to environmental heating and cooling and other thermal challenges such as anesthesia and non-ionizing radiation. In this contribution, a dynamic simulation model is presented and used to predict human thermophysiological and perceptual responses for different applications and situations. The multi-segmental, multi-layered mathematical model predicts body temperatures, thermoregulatory responses, and components of the environmental heat exchange in cold, moderate, as well as hot stress conditions. The incorporated comfort model uses physiological states of the human body to predict thermal sensation responses to steady state and transient conditions. Different validation studies involving climate-chamber physiological and thermal comfort experiments, exposures to uncontrolled outdoor weather conditions, extreme climatic and radiation asymmetry s...

Functional magnetic resonance imaging (fMRI) generates vast amounts of data. The handling, processing, and analysis of fMRI data would be inconceivable without computer-based methods. fMRI neuroinformatics is concerned with research, development, and operation of these methods. Reconstruction, rudimentary analysis, and visualization tools are implemented in software controlling modern MRI scanners. Research in advanced methods for analysis of subtle activation patterns, realistic physiological modeling, or integration of data from multiple subjects is the basis for a lively research field and has led to the development of a large number of tools.

A two-dimensional, seven link, nine degrees of freedom biped model was developed to investigate the dynamic characteristics of normal and transfemoral amputee locomotion during the entire gait cycle. The equations of motion were derived using the Lagrange method and the stance foot-ground contact was simulated using a five-point penetration model. The joint driving torques were obtained using forward dynamic optimization of the normal human gait and applied to the intact joints of the amputee. Three types of motion controllers; frictional, elastic and hydraulic were considered for the prosthetic joints of the amputee and their design parameters were optimized to achieve the closest kinematics to that of the normal gait. It was found that, if optimally designed, all three passive controllers could reasonably reproduce a normal kinematical pattern in the swing phase. However, the stance phase kinematics could only be replicated by the hydraulic and elastic controllers; the performance of the latter was highly sensitive to the design parameters. It was concluded that an appropriately designed hydraulic motion controller can provide reasonably normal kinematics and reliable stability for stance knee flexion prostheses. © 2013 Shandiz et al.; licensee InTech.

cdn.intechopen.com/pdfs/43698/InTech-A_robotic_model_of_transfemoral_amputee_locomotion_for_design_optimization_of_knee_controllers.pdf