37 research outputs found

    Design of an Efficient Controller for Arterial Oxygen Saturation in Neonatal Infants

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    A main problems for premature infants is respiratory distress syndrome (IRDS), also called neonatal respiratory distress syndrome, or respiratory distress syndrome of newborn. Due to IRDS, the infant requires intervention in the form of respiratory support to increase the inspired oxygen. Physicians must keep the range of the Arterial Oxygen Saturation (SpO_2) between 82 – 95% to help the premature infants to get oxygen enough while preventing other complications. If the blood oxygen saturation is more than 95% or less than 82%, the infant is at risk for retinopathy of prematurity. The control is analyzed using PI, PID, Model Predictive Controller (MPC), Robust control wit PID and Robust control with MPC to ensure stability and minimum settling time to reach the accuracy of output SpO_2 by applying the Fraction of Inspired Oxygen (FiO_2) as control action. MPC is an optimal control strategy based on numerical optimization by using a system model and optimizing at regular intervals. We can predict the future control inputs and future plant responses. An error model is created using the resulting ranges of system gains and time constant from [18]. The ?-synthesis controller is developed to control the oxygen percentage of inspired air and performance specifications are defined. The H_? method is used to determine the robust stability and robust performance are achieved with the system uncertainty that described by the error model. A comparison among a static proportional integral, proportional integral derivative, the model predictive controller, the robust controller with PID controller, and the robust controller with MPC found that the robust controller with MPC displays the best performance for a system with large ranges of model parameters. The results got from this dissertation are ; PI controller has large overshoots and large steady state error when using large values of K_I but when decreasing the values of K_I got good response with low overshoot and zero steady, PID controller has large overshoots and large steady state error when using large values of K_I and small values of K_p but when decreasing the values of K_I and increasing values of K_p got good response with low overshoot and zero steady, MPC controller has a zero steady state error and no peak overshoot and achieves SpO_2 to be a minimum settling time of 105 sec and zero steady state error, in robust control system based on the PID that showed the results of controller can guarantee stability and performance for whole range of model parameters and robust model predictive controller was analyzed, we did get the robust stability, nominal performance and robust performance. The robust controller is found to have a robust stability and performance, but with a low bandwidth frequency due to a conservative control design required to achieve robust stability with an extremely high level of model error. The main goal of the robust controller was analyzed for performance and stability. It was shown to be more nominally stable and have nominal performance and robust stability and performance. We showed that the result of controller can guarantee stability and performance for a whole range of model parameters. These results will help the respiratory infants to get alive in range of oxygen between 85% - 94%. It is very important to alleviate the workload of nurses in an intensive care unit when this controller is used to reduce the time and amount of harmful desaturation events

    Building Indoor Air Temperature and Humidity Control via Innovative Techniques

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    In this thesis a novel Model Reference Adaptive Control approach, developed to tame the thermohygrometric behaviour of buildings and to guarantee the indoor comfort, is presented. The main advantages of the proposed method are: i) robustness with respect to a large class of perturbations, external disturbances, nonlinear unmodelled dynamics or parameters uncertainty; ii) ability to impose some given profiles to the thermohygrometric variables, iii) accurate regulation and fast tracking of indoor air temperature and humidity in the case of stringent requirements in special building spaces. In order to analyse the effectiveness and robustness of the proposed control strategy, several case studies have been carried out. They refer to some reference buildings with different geometry, use and construction materials (also including phase change materials integrated into the building envelope) simulated in different weather conditions. In addition, the control of multi-zone thermal systems have been also considered in the relevant and innovative case of thermal zones completely included in others (e.g., an expo indoor space of a museum building including a display/case, special indoor hospitals spaces including multiple infant-incubators, etc.). Finally, model based control solutions have been designed for the control of the thermohygrometric dynamics in order to better point out the robustness of the adaptive solution to the computation of the required sensible loads. Results confirm the ability of the developed approach to achieve the selected indoor air temperature and humidity conditions in order to guarantee indoor comfort in uncertain conditions. In order to devise model based controllers, the design of a procedure for generating low order building models from detailed ones is proposed. The mismatch between the outputs of the simplified models with respect to those of the detailed ones have been measured quantitatively via a set of performance indexes. Results confirm that reduced order models of buildings can effectively predict i) indoor air temperature, ii) energy consumptions, iii) sensible heat demands, as well as iv) comfort of occupants (e.g., predicted mean vote, predicted percentage dissatisfied, and mean radiant temperature). Hence, they can be used not only for the design of advanced model based controllers, but also for i) reducing drastically the computation time to get an insight into building energy performance, especially when a large set of simulations are required, ii) deriving mathematical models of building dynamics via reverse engineering methods, when experimental data are available and iii) simulate cluster of buildings

    Integration and automation of a micro-tissue and microsphere based tissue engineering system and its application in cartilage regeneration and cancer models

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    Bottom-up biofabrication approaches for fabricating engineered tissue constructs are emerging strategies in tissue engineering. Few technologies have been developed that are capable of assembling tissue units into 3D Plotted scaffolds. We developed an integrated and automated 3D Bioassembly system for bioassembling engineered tissue constructs. The developed automated bioassembly system consisted of a (i) singularisation module and (ii) an injection module integrated into a commercial 3D bioprinter. The fluidic-based singularisation module delivered single Ø1 mm sized tissue unit at a time to the injection module and the injection module together with the 3D positioning system of the 3D bioprinter delivered the tissue unit into a predefined pore in the 3D Plotted scaffold. The developed automated bioassembly system was capable of either fabricating a construct via a two-step top-down bioassembly approach (fabricating a complete scaffold and insertion of tissue units) or a multistep bottom-up bioassembly approach (alternative layer-by-layer scaffold fabrication and tissue unit co-assembly). The automated bioassembly system was validated for application in cartilage and tumour engineering using tissue units (microspheres and micro-tissues). For cartilage engineering, Ø1 mm sized cartilage micro-tissues were fabricated utilising a previously demonstrated high-throughput 96-well plate format and Ø1 mm sized chondrocytes or chondroprogenitor cells-laden GelMA (gelatin-methacryloyl)-HepMA (methacrylated heparin) (9.5%-0.5%) hydrogel microspheres were fabricated utilising an adopted microfluidic system. For tumour engineering, a co-culture of cancer cells with fibroblasts using a liquid overlay technique was required to fabricate compact spherical Ø1 mm micro-tissues that could be handled by the automated bioassembly system and cancer cell-laden 10% GelMA hydrogel microspheres were fabricated utilising the adopted microfluidic system. Reliable handling of the tissue units was demonstrated by the automated bioassembly system. Bottom-up bioassembly of tissue units into 3D Plotted PEGT/PBT polymer scaffolds was demonstrated with the automated bioassembly system. No difference in viability was observed between the constructs assembled manually and with the automated bioassembly system. The flexibility of the automated tissue bioassembly system was shown by assembling constructs with coloured microspheres (denoting microspheres of different types) in various desired arrangements. The automated bioassembly of an anatomically shaped construct was also demonstrated. Neocartilage formation was observed in the chondrocyte-laden individual microspheres and assembled constructs when cultured in vitro for 35 days. Neocartilage formation was also visualised in the assembled graduated constructs fabricated with human articular chondrocytes (HAC) and mesenchymal stromal cells (MSC). In the in vitro micro-tissue tumour model, individual micro-tissues had higher chemoresistance compared to cells in 2D and the co-culture assembled construct had higher chemoresistance compared to individual co-culture micro-tissues. Similarly, in the in vitro microsphere tumour model, the assembled constructs were the most chemoresistant followed by individual microspheres and the cell in 2D had the lowest chemoresistance. The novel and flexible automated bioassembly technology that we have developed provides a pathway for fabricating a larger number of anatomically shaped clinically relevant constructs with precise control of the spatial position of the tissues units for application in cartilage engineering and for fabricating in vitro cancer models for application for drug discovery and high-throughput screening

    Prosiding Seminar Nasional Hasil-Hasil Penelitian Pascasarjana Tahun 2015

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    Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

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    In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf

    A longitudinal study of the experiences and psychological well-being of Indian surrogates

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    Study question: What is the psychological well-being of Indian surrogates during and after the surrogacy pregnancy? Summary answer: Surrogates were similar to a matched group of expectant mothers on anxiety and stress. However, they scored higher on depression during and after pregnancy. What is known already: The recent ban on trans-national commercial surrogacy in India has led to urgent policy discussions regarding surrogacy. Whilst previous studies have reported the motivations and experiences of Indian surrogates no studies have systematically examined the psychological well-being of Indian surrogates, especially from a longitudinal perspective. Previous research has shown that Indian surrogates are motivated by financial payment and may face criticism from their family and community due to negative social stigma attached to surrogacy. Indian surrogates often recruited by agencies and mainly live together in a “surrogacy house.” Study design, size, duration: A longitudinal study was conducted comparing surrogates to a matched group of expectant mothers over two time points: (a) during pregnancy (Phase1: 50 surrogates, 70 expectant mothers) and (b) 4–6 months after delivery (Phase 2: 45 surrogates, 49 expectant mothers). The Surrogates were recruited from a fertility clinic in Mumbai and the matched comparison group was recruited from four public hospitals in Mumbai and Delhi. Data collection was completed over 2 years. Participants/materials, setting, methods: Surrogates and expectant mothers were aged between 23 and 36 years. All participants were from a low socio-economic background and had left school before 12–13 years of age. In-depth faceto-face semi-structured interviews and a psychological questionnaire assessing anxiety, stress and depression were administered in Hindi to both groups. Interviews took place in a private setting. Audio recordings of surrogate interviews were later translated and transcribed into English. Main results and the role of chance: Stress and anxiety levels did not significantly differ between the two groups for both phases of the study. For depression, surrogates were found to be significantly more depressed than expectant mothers at phase 1 (p = 0.012) and phase 2 (p = 0.017). Within the surrogacy group, stress and depression did not change during and after pregnancy. However, a non-significant trend was found showing that anxiety decreased after delivery (p = 0.086). No participants reported being coerced into surrogacy, however nearly all kept it a secret from their wider family and community and hence did not face criticism. Surrogates lived at the surrogate house for different durations. During pregnancy, 66% (N = 33/50) reported their experiences of the surrogate house as positive, 24% (N = 12/50) as negative and 10% (N = 5/50) as neutral. After delivery, most surrogates (66%, N = 30/45) reported their experiences of surrogacy to be positive, with the remainder viewing it as neutral (28%) or negative (4%). In addition, most (66%, N = 30/45) reported that they had felt “socially supported and loved” during the surrogacy arrangement by friends in the surrogate hostel, clinic staff or family. Most surrogates did not meet the intending parents (49%, N = 22/45) or the resultant child (75%, N = 34/45). Limitations, reasons for caution: Since the surrogates were recruited from only one clinic, the findings may not be representative of all Indian surrogates. Some were lost to follow-up which may have produced sampling bias. Wider implications of the findings: This is the first study to examine the psychological well-being of surrogates in India. This research is of relevance to current policy discussions in India regarding legislation on surrogacy. Moreover, the findings are of relevance to clinicians, counselors and other professionals involved in surrogacy. Trial registration number: N/A

    Life Sciences Program Tasks and Bibliography for FY 1997

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    This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1997. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive internet web page

    Preface

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