Modeling and Control for Smart Grid Integration of Solar/Wind Energy Conversion System

Performance optimization, system reliability and operational efficiency are key characteristics of smart grid systems. In this paper a novel model of smart grid-connected PV/WT hybrid system is developed. It comprises photovoltaic array, wind turbine, asynchronous (induction) generator, controller and converters. The model is implemented using MATLAB/SIMULINK software package. Perturb and observe (P&O) algorithm is used for maximizing the generated power based on maximum power point tracker (MPPT) implementation. The dynamic behavior of the proposed model is examined under different operating conditions. Solar irradiance, temperature and wind speed data is gathered from a grid connected, 28.8kW solar power system located in central Manchester. Real-time measured parameters are used as inputs for the developed system. The proposed model and its control strategy offer a proper tool for smart grid performance optimization

Automatic Selective Encryption of DICOM Images

Securing DICOM images is essential to protect the privacy of patients, especially in the era of telemedicine and eHealth/mHealth. This increases the demand for rapid security. Nevertheless, a limited amount of research work has been conducted to ensure the security of DICOM images while minimizing the processing time. Hence, this paper introduces a selective encryption approach to reduce the processing time and sustain the robustness of security. The proposed approach selects regions within medical images automatically in the spatial domain using the pixel thresholding segmentation technique, then compresses and encrypts them using different encryption algorithms based on their importance. An adaptive two-region encryption approach is applied to single and multi-frame DICOM images, where the Region of Background (ROB) is encrypted using a light encryption algorithm, while the Region of Interest (ROI) is encrypted using a sophisticated encryption algorithm. For multi-frame DICOM images (Approach I), additional time-saving has been achieved by almost 10,000 times faster than the Naïve encryption approach, and 100 times better compression ratio, using one segmentation map based on a pre-defined reference frame for all the DICOM frames. For single-frame DICOM image (Approach II), a multi-region selective encryption approach is proposed, where the ROI is further split into three regions based on potential security threats, using a mathematical model that guarantees shorter encryption time in comparison with the Naive and the two-region encryption approaches, with almost 47% and 14% saving times, respectively. Based on the estimated processing time, Approach I outperformed Approach II noticeably. Further, cryptanalysis metrics are utilized to evaluate the proposed approaches, which indicate good robustness against a wide variety of attacks.</jats:p

Swept-source optical coherence tomography changes and visual acuity among Palestinian retinitis Pigmentosa patients: a cross-sectional study

Background: Retinitis pigmentosa (RP) is a heterogeneous group of inherited ocular diseases that result in progressive retinal degeneration. This study aims to describe different Swept-source Optical Coherence Tomographic (SS-OCT) changes in Palestinian RP patients and to explore possible correlations with Visual Acuity (VA). Methods: A cross-sectional observational study was conducted on Retinitis Pigmentosa patients diagnosed with RP in a tertiary eye hospital. Full history and ocular examination were made. SS-OCT imaging was done for all eyes assessing the presence of cystoid macular edema, epiretinal membrane, macular holes, and external limiting membrane, ellipsoid zone status. Also, central macular thickness and choroidal vascular thickness were measured. // Results: The study was run on 161 eyes of 81 patients; 53 males and 28 females. The average age at examination was 26.1 (6–78) years. Twenty-six eyes (16.1%) were of syndromic RP patients, mostly Usher syndrome; 20 eyes (12.4%). The mean Logaritmic minimal angle of resolution (LogMAR) of Best Corrected Visual Acuity (BCVA)of the study sample was 0.66 ± 0.7. The most prevalent change was cystoid macular edema [28 eyes, (17.4%)], followed by epiretinal membrane [17eye, (10.6%)]. A macular hole was noted only in one eye (0.6%). Ellipsoid zone and external limiting membrane were absent in 55 eyes (35.0%) and 60 eyes 37.5%. Vitreous hyperreflective foci were found in 35 eyes (43.8%). LogMAR of BCVA was associated significantly with cystoid macular edema (p = 0.001), ellipsoid zone(p = 0.001), and external limiting membrane (p = 0.001). // Conclusions: Detailed SS-OCT assessment in Palestinian patients diagnosed with RP identified different morphologies from other populations. Cystoid macular edema and vitreous hyperreflective foci may reflect signs of early or intermediate stages of the disease. Disease progression can be monitored by measuring the length/width (area) of ellipsoid zone +/− external limiting membrane and choroidal vascular thickness, which should be evaluated serially using high-resolution OCT

Mycophenolate mofetil modulates adhesion receptors of the beta1 integrin family on tumor cells: impact on tumor recurrence and malignancy

BACKGROUND: Tumor development remains one of the major obstacles following organ transplantation. Immunosuppressive drugs such as cyclosporine and tacrolimus directly contribute to enhanced malignancy, whereas the influence of the novel compound mycophenolate mofetil (MMF) on tumor cell dissemination has not been explored. We therefore investigated the adhesion capacity of colon, pancreas, prostate and kidney carcinoma cell lines to endothelium, as well as their beta1 integrin expression profile before and after MMF treatment. METHODS: Tumor cell adhesion to endothelial cell monolayers was evaluated in the presence of 0.1 and 1 μM MMF and compared to unstimulated controls. beta1 integrin analysis included alpha1beta1 (CD49a), alpha2beta1 (CD49b), alpha3beta1 (CD49c), alpha4beta1 (CD49d), alpha5beta1 (CD49e), and alpha6beta1 (CD49f) receptors, and was carried out by reverse transcriptase-polymerase chain reaction, confocal microscopy and flow cytometry. RESULTS: Adhesion of the colon carcinoma cell line HT-29 was strongly reduced in the presence of 0.1 μM MMF. This effect was accompanied by down-regulation of alpha3beta1 and alpha6beta1 surface expression and of alpha3beta1 and alpha6beta1 coding mRNA. Adhesion of the prostate tumor cell line DU-145 was blocked dose-dependently by MMF. In contrast to MMF's effects on HT-29 cells, MMF dose-dependently up-regulated alpha1beta1, alpha2beta1, alpha3beta1, and alpha5beta1 on DU-145 tumor cell membranes. CONCLUSION: We conclude that MMF possesses distinct anti-tumoral properties, particularly in colon and prostate carcinoma cells. Adhesion blockage of HT-29 cells was due to the loss of alpha3beta1 and alpha6beta1 surface expression, which might contribute to a reduced invasive behaviour of this tumor entity. The enhancement of integrin beta1 subtypes observed in DU-145 cells possibly causes re-differentiation towards a low-invasive phenotype

Technology Based-Entrepreneurship: Measurement Technology Perspective

Currently, there are several papers on the New Technology Based Firms (NTBFs) yet the case studies of measurement technology appear to not be available. This work aims to present the entrepreneurial processes of Finnish measurement technology firms. Eight interviews were conducted with the key players of the industry. Successfully, the outcomes of the study revealed that there are five interconnected and interactive phases for new technology commercialization; they are not static and they are continuous in a circular mode. Likewise, there are two facilitators – networking and market potential which serve as linked pins for the identified stages. Furthermore, financing, research and development (R&D), government supports and the entrepreneurship issues were found to be highly relevant for NTBFs. Most importantly, this study presents a new model, which can be adopted by technology entrepreneurs for their invention valorizations.</p

Investigation into the characteristics of proton exchange membrane fuel cell-based power system

© The Institution of Engineering and Technology.Fuel cells (FCs) use hydrogen as their prime fuel source, which promotes them as one of the attractive options for clean energy generators. Though they have been around for some time, their characteristics are not yet fully understood. This study offers a thorough investigation into the characteristics of proton exchange membrane (PEM) type of FCs based power system. This study first presents a concise explanation of the working principles of the PEM electrolyser and FCs supported by novel modelling using MATLAB. The simulation results are then validated by a series of experiments carried out on operational 500 mW FC followed by detailed performance parameters of such type of FCs. Parameters affect the efficiencies of each part of the system are investigated and the total system's efficiency is then calculated. The efficiency of the electrolyser and PEM FC was found to be 85 and 60%, respectively. Polarisation curve has been used in order to evaluate FC's performance. From the polarisation curve, it is noted the efficiency of the FC increases with increasing pressure and temperature. The activation losses are reduced when the temperature increased. Moreover, the mass transfer is enhanced toward reducing the PEMFC's resistance

Identifying the Challenges in Commercializing High Technology: A Case Study of Quantum Key Distribution Technology

This article examines the challenges in commercializing high technologies successfully and sustainably using quantum key distribution (QKD) technology as a case study. Quantum communication is increasingly relevant to cybersecurity and nanotechnology, which will replace current technologies and change the way we live. To understand how such high technology could be successfully commercialized, we interviewed individuals from four metrology institutions and two international companies. The result revealed that scattered and small markets, supply chain development, technology validation/certification, a lack of available or adequate infrastructure, and after-sales services are the most serious challenges facing successful commercialization of quantum communication technology. To validate these challenges, we conducted a survey of 60 experts, 49 of whom agreed that above-mentioned factors could affect the commercialization success of QKD technology. Likewise, the survey revealed that technical development, customer orientation/awareness, and government regulations could also hinder the commercialization of QKD technology.  </p

Characterizing Goal-Directed Behavior in Children with Attention-Deficit/Hyperactivity Disorde

Attention-deficit hyperactivity disorder (ADHD) is characterized by symptoms of inattention, impulsivity and hyperactivity. Children with ADHD show impaired motivational behavior. For example, they tend to select small, immediate over large, delayed rewards. They might be unable to predict the consequences of their actions showing a deficit in action-control strategies. Goals and habits are the two behavioral mechanisms that control actions. Balancing these two behaviors leads to normal action-control. In previous studies, we found that rat models of ADHD demonstrated over-reliance on habits and poor goal-directed actions. This deficit was restored by administering methylphenidate (the most commonly used psychostimulant in ADHD treatment), dopamine D2 receptor agonist or dopamine D1 receptor antagonist. Further, in another pilot study, we found that children with ADHD are less reliant on goal-directed behavior compared to healthy children. In this study, we examined action-control patterns in children with ADHD on- and off- methylphenidate. We hypothesize that on-methylphenidate patients will show different patterns of action-control compared to off-methylphenidate patients. We tested 7 off-medication and 7 on-medication, 6-10 years old children with ADHD, and 13 healthy controls. Participants were 6-10 years old and were group matched for age and sex. We tested patterns of action-control using a computer-based task of the outcome devaluation paradigm that consists of three phases; a training phase, a devaluation phase and a choice test. Children with ADHD were successful at acquiring action-outcome associations as well as showing higher tendency on goal-directed responses. However, throughout the task, on- methylphenidate children showed (1) lower number of errors, (2) higher reaction times and (3) no difference in action-control responses (goals vs. habits). These results indicate that methylphenidate was beneficial in modulating symptoms of ADHD by reducing the number of errors during learning and increasing children’s response times; but it was not effective in improving children’s cognitive profile, reflected by similar action-control patterns in both on and off-medication states

Mechanisms behind temsirolimus resistance causing reactivated growth and invasive behavior of bladder cancer cells in vitro

Background: Although mechanistic target of rapamycin (mTOR) inhibitors, such as temsirolimus, show promise in treating bladder cancer, acquired resistance often hampers efficacy. This study evaluates mechanisms leading to resistance. Methods: Cell growth, proliferation, cell cycle phases, and cell cycle regulating proteins were compared in temsirolimus resistant (res) and sensitive (parental—par) RT112 and UMUC3 bladder cancer cells. To evaluate invasive behavior, adhesion to vascular endothelium or to immobilized extracellular matrix proteins and chemotactic activity were examined. Integrin α and β subtypes were analyzed and blocking was done to evaluate physiologic integrin relevance. Results: Growth of RT112res could no longer be restrained by temsirolimus and was even enhanced in UMUC3res, accompanied by accumulation in the S- and G2/M-phase. Proteins of the cdk-cyclin and Akt-mTOR axis increased, whereas p19, p27, p53, and p73 decreased in resistant cells treated with low-dosed temsirolimus. Chemotactic activity of RT112res/UMUC3res was elevated following temsirolimus re-exposure, along with significant integrin α2, α3, and β1 alterations. Blocking revealed a functional switch of the integrins, driving the resistant cells from being adhesive to being highly motile. Conclusion: Temsirolimus resistance is associated with reactivation of bladder cancer growth and invasive behavior. The α2, α3, and β1 integrins could be attractive treatment targets to hinder temsirolimus resistance