Identification, state estimation, and adaptive control of type i diabetic patients

ABSTRACT IDENTIFICATION, STATE ESTIMATION, AND ADAPTIVE CONTROL OF TYPE I DIABETIC PATIENTS by ALI MOHAMAD HARIRI May 2012 Advisor: Dr. Le Yi Wang Major: Electrical Engineering Degree: Doctor of Philosophy During the past few decades, biomedical modeling techniques have been applied to improve performance of a wide variety of medical systems that require monitoring and control. Diabetes is one of the most important medical problems. Most of the existing techniques assume the system to be time-invariant, and the original minimal model was modified by deleting some important parameters. In this research, the original minimal model that consists of three differential equations is used. A new differential equation represents a first order infusion pump is added to the set of the differential equations of the minimal model. The Nonlinear Least Squares Method with Levenberg-Marquardt Algorithm is used to estimate the unknown parameters of the differential equations. A new regime-switching control scheme using Proportional-Integral-Derivative (PID) controllers is designed to ensure that the control specifications are met. By comparing different switching schemes, we show that switched PID controllers can improve performance, but frequent switching of controllers is unnecessary. These findings lead to a control strategy that utilizes only a small number of PID controllers in this scheduled adaptation strategy. The regime-switching scheme proves that adaptive control can potentially improve system performance. But it increases control complexity and may create further stability issues. This research investigates patient models and presents a simplified control scheme using observer-based state feedback controller that is able to enhance the performance of the system and meet the design specifications. By comparing different control schemes, it shows that a properly designed observer-based state feedback controller can eliminate the adaptation strategy that PID regime-switching control scheme needs to improve the control performance. Also, the observer-based state feedback control scheme reduces the complexity of the control circuit by eliminating the adaptive control switching components and reduces the cost to build up the circuits

Low attenuation microwave waveguides

PhDAn investigation of the dispersion and attenuation characteristics of cylindrical structures supporting guided electromagnetic waves with low attenuation is described. The object of the investigation is to understand how the cross-sectional shape and the nature of the boundary conditions affects the propagation characteristics. Attention is directed towards structures supporting the least number of propagating modes under the conditions which yield low attenuation over a reasonable bandwidth. Elliptical waveguides with both smooth-walls and corrugated walls are studied in detail. This reveals errors in previous-theories which are corrected. Some aspects of corrugated rectangular and circular waveguides are considered. Potential low attenuation waveguides such as the dielectric lined and dielectric waveguides are evaluated

The Effect of Probe Pressure on In Vivo Single Fiber Reflectance Spectroscopy

Introduction: Single fiber reflectance spectroscopy (SFRS) is a noninvasive procedure to quantitate tissue absorption and scattering properties. It can be used to diagnose different diseases such as malignancy and pre-cancerous conditions. The measurement is done with a fiber optic probe in contact with the tissue surface. Herein, the effect of probe pressure on the extracted parameters from human lip spectra was studied.Methods: Thirty-three normal subjects were examined with three exerted pressure levels on the right, middle and left parts of their lips.Results: The results showed variation of spectroscopic parameters with different pressure levels. However, the effect was seen between a very mild contact (pressure 1) and the other reasonably practical pressure levels normally used in the medical centers.Conclusion: SFRS can be used as a reliable diagnostic tool in clinics

Molecular imaging of oxidative stress using an LED-based photoacoustic imaging system.

LED-based photoacoustic imaging has practical value in that it is affordable and rugged; however, this technology has largely been confined to anatomic imaging with limited applications into functional or molecular imaging. Here, we report molecular imaging reactive oxygen and nitrogen species (RONS) with a near-infrared (NIR) absorbing small molecule (CyBA) and LED-based photoacoustic imaging equipment. CyBA produces increasing photoacoustic signal in response to peroxynitrite (ONOO-) and hydrogen peroxide (H2O2) with photoacoustic signal increases of 3.54 and 4.23-fold at 50 µM of RONS at 700 nm, respectively. CyBA is insensitive to OCl-, ˙NO, NO2-, NO3-, tBuOOH, O2-, C4H9O˙, HNO, and ˙OH, but can detect ONOO- in whole blood and plasma. CyBA was then used to detect endogenous RONS in macrophage RAW 246.7 cells as well as a rodent model; these results were confirmed with fluorescence microscopy. Importantly, CyB suffers photobleaching under a Nd:YAG laser but the signal decrease is <2% with the low-power LED-based photoacoustic system and the same radiant exposure time. To the best of our knowledge, this is the first report to describe molecular imaging with an LED-based photoacoustic scanner. This study not only reveals the sensitive photoacoustic detection of RONS but also highlights the utility of LED-based photoacoustic imaging

Co-citation scientific maps: A case study of medical sciences in Iran

Visualization of scientific maps enhances the awareness and general recognition of the scientific domains and their structures. It facilitates the study of the existing situation and planning of the future researches as well. The present study sought to discover and generate the scientific map of medicine in Iran between 2003 and 2007. It also aimed to determine the most effective medical subject categories in the map generated. The study follows a scientometrics trend in which all published articles of Iran indexed in the Science Citation Index Expanded (SCIE) between 2003 and 2007 were retrieved. Then, these articles were limited to medical subject categories through the result analysis section of SCIE and 10247 articles were retrieved in medical subject categories as research population. NWB (Network Workbench Tool) software and ISI medical subject category co-citation were used for analyzing the articles in medicine and generating scientific maps. The scientific medical map showed that there were 61 nodes and 164 links with a weight ranging from 101 to 591. 31 nodes depicted one medical subject category, while the other nodes covered non-medical, or a combination of medical and non-medical subject categories. Medical subject categories with the highest impact included general and internal medicine, pharmacology and pharmacy, biochemistry and molecular biology, neurosciences, and research and experimental medicine. The strongest links were visible in general and internal medicine, with public, occupational, and environmental health; general and internal medicine with pharmacology and pharmacy; and pharmacology and pharmacy with neurosciences. The quantitative growth in medical articles alongside their quality is effective in scientific maps. It is necessary to encourage the categories with more effective and support the subject categories with the least impact to publish more articles and get more citation.

The effect of soy protein containing soy isoflavones on serum concentration of cell adhesion molecules : A systematic review and meta-analysis of randomized controlled trials

Funding Information: This study was financially supported by Neyshabur University of Medical Sciences (Grant number: 98-01-149 ; Ethical code: IR.NUMS.REC.1399.006). Acknowledgement We are extremely grateful to the data collection team at the Ney- shabur University of Medical Sciences.Peer reviewedPublisher PD

Diffusion-weighted MRI in liver fibrosis staging: Added value of normalized ADC using spleen and renal cortex as reference organs

AbstractAimTo evaluate the potential value of the spleen and renal cortex as a reference organ to improve the performance of DWI in the assessment of liver fibrosis.Material and methods44 subjects were included: 30 patients with chronic viral hepatitis and 14 age matched volunteers. They were subjected to diffusion weighted MRI (DWI). Liver ADC, normalized ADC (ratio between ADC of liver to spleen (S-ADC) and renal cortex (R-ADC)) was calculated. Data was analyzed and ROC was used to evaluate the performance of ADC, S-ADC and R-ADC.ResultsNo significant difference between spleen ADC and renal ADC values between patient group and control group or in-betweens different fibrosis stages. The mean liver ADC was significantly lower in cirrhotic patients than control group (1.59±0.024 versus 1.55±0.036×10−3mm2/s, P=0.009) with some overlap in different fibrosis grades.With exception to stage 1 fibrosis, the mean S-ADC value was significantly lower in patients with different hepatic fibrosis stages in comparison to control group (P 0.02–<0.001). Significant negative correlation was noted between S-ADC value and fibrosis stage (r=−0.75, p<0.001). It had significant difference between stage 0 compared to stage 2, 3, and 4 as well as between stage 4 in comparison to stage 1, 2 and 3. S-ADC had a significant ability to differentiate between stages 0–1 Vs stage 2–4, stage 0–2 Vs stage 3–4 as well as stage 0–3 Vs stage 4.Significant negative correlation was noted between R-ADC value and fibrosis stage (r=−0.68, p<0.001). The mean R-ADC value was lower in patients with liver fibrosis compared to volunteers with significant difference between stage 0 and 3 and between stage 0 and 4 (P<0.001). It had significant difference between stage 0 compared to stage 3, and 4 as well as in stage 4 in comparison to stage 1 and 2. R-ADC has a significant ability to differentiate between stages 0–1 Vs stage 2–4, stage 0–2 Vs stage 3–4 as well as stage 0–3 Vs stage 4.ROC analysis showed higher performance using S-ADC in comparison to liver ADC and R-ADC while R-ADC had higher performance in comparison to liver ADC. The AUC, sensitivity, specificity, PPV, NPV and k-value for detection of fibrotic stages ⩾2 (0.85, 95.8%, 60%, 74%, 92% and 0.85 for S-ADC Vs 0.68, 66.7%, 60%, 66%, 60% and 0.28 for ADC and 0.85, 95.8%, 50%, 69%, 91% and 0.47 for R-ADC). and in detection of fibrotic stages ⩾3 was (0.86, 100%, 52%, 61%, 100% and 0.48 for S-ADC Vs 0.63, 63%, 52%, 50%, 65% and 0.14 for ADC and 0.88, 100%, 44%, 57%, 100% and 0.40 for R-ADC) while for fibrosis stage 4, the corresponding values was (1, 100%, 100%, 100%, 100% and 1 for S-ADC Vs 0.7, 81%, 54%, 37%, 90% and 0.26 for ADC and 0.65, 100%, 65%, 45%, 100% and 0.43 for R-ADC) respectively.ConclusionNormalized liver ADC using the spleen and kidney increases the performance of ADC in the evaluation of liver fibrosis which is highest in spleen normalized ADC

Thermocapillary motion of deformable drops

The thermocapillary motion of initially spherical drops/bubbles driven by a constant temperature gradient in an unbounded liquid medium is simulated numerically. Effects of convection of momentum and energy, as well as shape deformations, are addressed. The method used is based on interface tracking on a base cartesian grid, and uses a smeared color or indicator function for the determination of the surface topology. Quad-tree adaptive refinement of the cartesian grid is implemented to enhance the fidelity of the surface tracking. It is shown that convection of energy results in a slowing of the drop, as the isotherms get wrapped around the front of the drop. Shape deformation resulting from inertial effects affect the migration velocity. The physical results obtained are in agreement with the existing literature. Furthermore, remarks are made on the sensitivity of the calculated solutions to the smearing of the fluid properties. Analysis and simulations show that the migration velocity depends very strongly on the smearing of the interfacial force whereas it is rather insensitive to the smearing of other properties, hence the adaptive grid