179 research outputs found

    Design and Evaluation of FPGA-based Hybrid Physically Unclonable Functions

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    A Physically Unclonable Function (PUF) is a new and promising approach to provide security for physical systems and to address the problems associated with traditional approaches. One of the most important performance metrics of a PUF is the randomness of its generated response, which is presented via uniqueness, uniformity, and bit-aliasing. In this study, we implement three known PUF schemes on an FPGA platform, namely SR Latch PUF, Basic RO PUF, and Anderson PUF. We then perform a thorough statistical analysis on their performance. In addition, we propose the idea of the Hybrid PUF structure in which two (or more) sources of randomness are combined in a way to improve randomness. We investigate two methods in combining the sources of randomness and we show that the second one improves the randomness of the response, significantly. For example, in the case of combining the Basic RO PUF and the Anderson PUF, the Hybrid PUF uniqueness is increased nearly 8%, without any pre-processing or post-processing tasks required. Two main categories of applications for PUFs have been introduced and analyzed: authentication and secret key generation. In this study, we introduce another important application for PUFs. In fact, we develop a secret sharing scheme using a PUF to increase the information rate and provide cheater detection capability for the system. We show that, using the proposed method, the information rate of the secret sharing scheme will improve significantly

    3D Printed TCP-Based Scaffold Incorporating VEGF-Loaded PLGA Microspheres for Craniofacial Tissue Engineering

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    Objective Vascularization is a critical process during bone regeneration/repair and the lack of tissue vascularization is recognized as a major challenge in applying bone tissue engineeringmethods for cranial and maxillofacial surgeries. The aim of our study is to fabricate a vascular endothelial growth factor (VEGF)-loaded gelatin/alginate/β-TCP composite scaffold by 3D printing method using a computer-assisted design (CAD) model. Methods The paste, composed of (VEGF-loaded PLGA)-containing gelatin/alginate/β-TCP in water, was loaded into standard Nordson cartridges and promptly employed for printing the scaffolds. Rheological characterization of various gelatin/alginate/β-TCP formulations led to an optimized paste as a printable bioink at room temperature. Results The in vitro release kinetics of the loaded VEGF revealed that the designed scaffolds fulfill the bioavailability of VEGF required for vascularization in the early stages of tissue regeneration. The results were confirmed by two times increment of proliferation of human umbilical vein endothelial cells (HUVECs) seeded on the scaffolds after 10 days. The compressive modulus of the scaffolds, 98 ± 11 MPa, was found to be in the range of cancellous bone suggesting their potential application for craniofacial tissue engineering. Osteoblast culture on the scaffolds showed that the construct supports cell viability, adhesion and proliferation. It was found that the ALP activity increased over 50% using VEGF-loaded scaffolds after 2 weeks of culture. Significance The 3D printed gelatin/alginate/β-TCP scaffold with slow releasing of VEGF can be considered as a potential candidate for regeneration of craniofacial defects

    Development of 3D PCL microsphere/TiO\u3csub\u3e2\u3c/sub\u3e nanotube composite scaffolds for bone tissue engineering

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    In this research, the three dimensional porous scaffolds made of a polycaprolactone (PCL) microsphere/TiO2 nanotube (TNT) composite was fabricated and evaluated for potential bone substitute applications. We used a microsphere sintering method to produce three dimensional PCL microsphere/TNT composite scaffolds. The mechanical properties of composite scaffolds were regulated by varying parameters, such as sintering time, microsphere diameter range size and PCL/TNT ratio. The obtained results ascertained that the PCL/TNT (0.5 wt%) scaffold sintered at 60 °C for 90 min had the most optimal mechanical properties and an appropriate pore structure for bone tissue engineering applications. The average pore size and total porosity percentage increased after increasing the microsphere diameter range for PCL and PCL/TNT (0.5 wt%) scaffolds. The degradation rate was relatively high in PCL/TNT (0.5 wt%) composites compared to pure PCL when the samples were placed in the simulated body fluid (SBF) for 6 weeks. Also, the compressive strength and modulus of PCL and PCL/TNT (0.5 wt%) composite scaffolds decreased during the 6 weeks of storage in SBF. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay and alkaline phosphates (ALP) activity results demonstrated that a generally increasing trend in cell viability was observed for PCL/TNT (0.5 wt%) scaffold sintered at 60 °C for 90 min compared to the control group. Eventually, the quantitative RT-PCR data provided the evidence that the PCL scaffold containing TiO2 nanotube constitutes a good substrate for cell differentiation leading to ECM mineralization

    Evaluating Alternative Water Allocation Policies Among Competing Users In Bow River Basin, Alberta, Canada

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    Demand for water from rivers and aquifers for consumptive use has grown greatly due to population and economic growth and changing lifestyle and dietary habits. Consequently, aquatic ecosystems, especially in semi-arid and arid regions across the world, suffer adverse environmental impacts of over-extraction. Historically, Alberta’s water allocation system has been based on the first-in-time-first-in-right (FITFIR) system, granting the preference to the licensees based on the seniority of their licenses. In recent years, scientists, policy makers, and water users have raised questions whether FITFIR will continue to be the most appropriate allocation system to manage increasing scarce water resources in Alberta. This study aims to investigate the current and proposed water allocation strategies in Alberta and their impacts on existing consumptive users, the environment, and the economy. Specifically, existing and four allocation alternatives are evaluated using a series of criteria that measure to what extend the system can achieve its multiple goals. The study employs Bow River Basin a case study and the OASIS model is employed to simulate the flow model based on the current allocation mechanism and alternative operational rules. It is concluded that comparing with existing allocation mechanism, alternative of stabilizing Kananaskis River has multiple benefits to fisheries, irrigation and recreational users, and helps to improve the reliability of supply of the entire basin. It does not, however, improve the environmental flow substantially. The addition of 60,000 acre feet of water banks drastically improve the environmental flow so does a further addition of 61,000 acre feet to spray reservoir. But it is the alternative of adding 40,000 acre feet of water bank while stabilizing Kananaskis River that provides the optimal water allocation strategy in achieving simultaneously economic and environmental goals and meeting the need of existing consumptive users

    Improving energy efficiency considering reduction of CO2 emission of turnip production:A novel data envelopment analysis model with undesirable output approach

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    Modern Turnip production methods need significant amount of direct and indirect energy. The optimum use of agricultural input resources results in the increase of efficiency and the decrease of the carbon footprint of turnip production. Data Envelopment Analysis (DEA) approach is a well-known technique utilized to evaluate the efficiency for peer units compared with the best practice frontier, widely used by researches to analyze the performance of agricultural sector. In this regard, a new non-radial DEA-based efficiency model is designed to investigate the efficiency of turnip farms. For this purpose, five inputs and two outputs are considered. The outputs consist turnip yield as a desirable output and greenhouse gas emission as an undesirable output. The new model projects each DMU on the strong efficient frontier. Several important properties are stated and proved which show the capabilities of our proposed model. The new models are applied in evaluating 30 turnip farms in Fars, Iran. This case study demonstrates the efficiency of our proposed models. The target inputs and outputs for these farms are also calculated and the benchmark farm for each DMU is determined. Finally, the reduction of CO2 emission for each turnip farm is evaluated. Compared with other factors like human labor, diesel fuel, seed and fertilizers, one of the most important findings is that machinery has the highest contribution to the total target energy saving. Besides, the average target emission of turnip production in the region is 7% less than the current emission

    Development of Chitosan/Gelatin/Keratin Composite Containing Hydrocortisone Sodium Succinate as a Buccal Mucoadhesive Patch to Treat Desquamative Gingivitis

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    The aim of this research was to develop chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis, which was fabricated through an environmental friendly process. Mucoadhesive films increase the advantage of higher efficiency and drug localization in the affected region. In this research, mucoadhesive films, for the release of hydrocortisone sodium succinate, were prepared using different ratios of chitosan, gelatin and keratin. In the first step, chitosan and gelatin proportions were optimized after evaluating the mechanical properties, swelling capacity, water uptake, stability, and biodegradation of the films. Then, keratin was added at different percentages to the optimum composite of chitosan and gelatin together with the drug. The results of surface pH showed that none of the samples were harmful to the buccal cavity. FTIR analysis confirmed the influence of keratin on the structure of the composite. The presence of a higher amount of keratin in the composite films resulted in high mechanical, mucoadhesive properties and stability, low water uptake and biodegradation in phosphate buffer saline (pH = 7.4) containing 104 U/ml lysozyme. The release profile of the films ascertained that keratin is a rate controller in the release of the hydrocortisone sodium succinate. Finally, chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate can be employed in dental applications

    Antiphospholipid Antibodies in Women with Recurrent Urinary Tract Infection

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    Background: A variety of infections, including acute and recurrent urinary tract infections (UTIs), can trigger production of antiphospholipid antibodies (aPL).  These antibodies in women can lead to recurrent pregnancy loss. The aim of this study was to evaluate the prevalence of aPL in recurrent UTI patients.Materials and Methods: A total 52 subjects who had positive urine culture and 50 healthy individuals as controls were evaluated for presence of lupus anticoagulant (LA), anticardiolipin, anti-β2 GPI(anti-2-glycoprotein I) autoantibodies  IgM and IgG and Interleukin-8 levels. Determination of lupus anticoagulant was done by Activated Partial Thromboplastin Time (aPTT). Anticardiolipin and anti-β2 GPI autoantibodies were evaluated by ELISA method. Interleukin-8 values were also evaluated using ELISA method. Results: Escherichia coli (86.61%) and Proteus mirabilis (1.92%) had the highest and lowest frequency respectively. The prevalence of anti- β2 GPI IgG and IgM isotypes and anticardiolipin IgG and IgM isotypes or LA in UTI patients and healthy controls was 0.0%. There was significant association between neutrophil counts and IL-8 levels at the p < 0.01.Conclusion: Our results showed that in the UTI group and controls evaluated antiphospholipid antibodies were not present. The production of antiphospholipid antibodies is influenced by various genetic and environmental factors and chronic urinary tract infection alone is not the cause. This can affect the prevalence of antiphospholipid antibodies in various populations. However, other factors, such as the type of antiphospholipid antibody, sampling season and methodology can affect the results

    Control System and Graphical User Interface Design of an Upper-Extremity Rehabilitation Robot

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    Stroke is one of the leading causes of death, physical disability, and loss of brain functionality each year, especially amongst older adults. The ability to access good quality post-stroke rehabilitation exercises is essential for stroke survivors to maximize their potential to regain skills and physical abilities. Robot-assisted therapy is showing promise as a way to provide stroke survivors with engaging, challenging, and repetitive tasks while delivering measured therapy that is able to objectively evaluate patients’ progress. Among several challenges that are associated with the design of rehabilitation robots (e.g., the mechanical structure, the actuator types, the control strategies), the design of the control strategy is one of the most critical. Depending on the type of patient and the severity of the impairment of motor control, various control strategies could be applied for the recovery of the impaired limb in stroke survivors using robot-assisted therapy. Research is needed into the development of how best to control rehabilitation robots; this includes both the internal control algorithms and the User Interface (UI) for therapists. As such, the first objective of this research is to design and implement a motion controller and force-field controller for a 2-Degree of Freedom (DOF) manipulandum upper-extremity rehabilitation robot that is able to deliver planar rehabilitation exercises for stroke survivors while taking therapeutic rehabilitation goals into account. The motion control algorithm can precisely follow a prescribed time-dependent trajectory whereas the force-control method will only provide assistance (or even resistance to introduce extra challenge) to the patient to do the task rather than forcing the movement. For doing the simulation studies, a motor control model of post-stroke patients was proposed. The effectiveness of these controllers was explored in simulations and it was observed that the developed force-field algorithm had a positive effect on the motor control recovery for a simulated patient. The simulation results also indicated that the resistive mode of therapy would result in better outcomes after the therapy which aligns with experimental studies by other researchers. In addition, a novel adaptive algorithm was proposed for fine-tuning the proposed force-field parameters based on the performance of the patient during the therapy as a subject specific controller can help to achieve a desirable performance for each patient. While this approach is promising, the effectiveness of the adaptation rule has yet to be evaluated on real patients in the future. To enable effective access and use of the robot, the controller needs to be visualized through a Graphical User Interface (GUI) in a way that therapists can understand and use. The second goal of this thesis research was to work with therapists to collaboratively design an intuitive to use GUI for therapists to control the robot and provide objective information on patients’ performance. The identification of features and feedback on the intuitiveness of the GUI developed in this research highlights the value of collaborative design between engineers and therapists to create the interface that enables therapists to control the rehabilitation robot. This research also identifies the need for collaborative GUI design with patients as their needs and preference may be different from therapists. During the collaborative GUI design, it was observed that including obstacles and force-field method might be a possible useful method for supporting patients’ movement trajectory, not only because therapists can adjust the force strength to suit a specific patient, but also because they can use its numerical data for objective measurement of patients’ performance. Therapists who participated in this research stated that objective measurements (i.e., trajectory smoothness, speed, mobility range, and error) could be used to evaluate the patient performance. While rehabilitation robots are different in terms of mechanical structure, work-space, and the exercise that they can provide, similar methods could be used for supporting patients’ movement trajectory and performance evaluation. As the GUI is the first prototype, it needs to be used with and evaluated by therapists and patients to ascertain if the information presented in the GUI is intuitive and to explore if they can understand it or use it

    A Current Overview of Materials and Strategies for Potential Use in Maxillofacial Tissue Regeneration

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    Tissue regeneration is rapidly evolving to treat anomalies in the entire human body. The production of biodegradable, customizable scaffolds to achieve this clinical aim is dependent on the interdisciplinary collaboration among clinicians, bioengineers and materials scientists. While bone grafts and varying reconstructive procedures have been traditionally used for maxillofacial defects, the goal of this review is to provide insight on all materials involved in the progressing utilization of the tissue engineering approach to yield successful treatment outcomes for both hard and soft tissues. In vitro and in vivo studies that have demonstrated the restoration of bone and cartilage tissue with different scaffold material types, stem cells and growth factors show promise in regenerative treatment interventions for maxillofacial defects. The repair of the temporomandibular joint (TMJ) disc and mandibular bone were discussed extensively in the report, supported by evidence of regeneration of the same tissue types in different medical capacities. Furthermore, in addition to the thorough explanation of polymeric, ceramic, and composite scaffolds, this review includes the application of biodegradable metallic scaffolds for regeneration of hard tissue. The purpose of compiling all the relevant information in this review is to lay the foundation for future investigation in materials used in scaffold synthesis in the realm of oral and maxillofacial surgery

    Mechanical Properties of 3D Printed Reinforced Polycaprolactone Composite Scaffolds

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    Objectives This paper describes the fabrication of a new porous 3D-printed scaffold composed of polycaprolactone (PCL) and polyether-ether ketone (PEEK) micro-particles for bone tissue engineering (BTE) applications. Methods In order to improve the compatibility of the reinforcing PEEK powder with polycaprolactone, the PEEK powder was surface-modified by an amino-silane coupling agent. After modification, Fourier-transform infrared spectrometry (FTIR) and differential scanning calorimetry (DSC) were used to investigate the chemical reaction between PEEK and silane coupling agent. In order to increase the compressive modulus of the 3D printed PCL scaffold, 10% silane-modified PEEK was incorporated into the PCL polymeric matrix. Scanning electron microscopy (SEM) was used for cell morphology and attachment evaluation. Results The results indicated that the silane coupling agent was successfully grafted onto the particle surface. The compressive modulus of PCL scaffold increased by incorporating the silane-modified PEEK, despite having higher porosity, compared with the pure PCL scaffolds. Addition of amino-silane had a positive impact on cell response, and that surface modification led to improved particle dispersion. Conclusion In conclusion, it seems that the incorporation of surface-modified PEEK micro-particles into the PCL porous scaffold could enhance its mechanical properties, and may be applicable for the management of large bone defects
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