Latest Articles

Open AccessReview
Recent Advances in Fabrication Methods for Flexible Antennas in Wearable Devices: State of the Art
Sensors 2019, 19(10), 2312; https://doi.org/10.3390/s19102312 (registering DOI) -
Abstract
Antennas are a vital component of the wireless body sensor networks devices. A wearable antenna in this system can be used as a communication component or energy harvester. This paper presents a detailed review to recent advances fabrication methods for flexible antennas. Such [...] Read more.
Antennas are a vital component of the wireless body sensor networks devices. A wearable antenna in this system can be used as a communication component or energy harvester. This paper presents a detailed review to recent advances fabrication methods for flexible antennas. Such antennas, for any applications in wireless body sensor networks, have specific considerations such as flexibility, conformability, robustness, and ease of integration, as opposed to conventional antennas. In recent years, intriguing approaches have demonstrated antennas embroidered on fabrics, encapsulated in polymer composites, printed using inkjets on flexible laminates and a 3-D printer and, more interestingly, by injecting liquid metal in microchannels. This article presents an operational perspective of such advanced approaches and beyond, while analyzing the strengths and limitations of each in the microwave as well as millimeter-wave regions. Navigating through recent developments in each area, mechanical and electrical constitutive parameters are reviewed, and finally, some open challenges are presented as well for future research directions. Full article
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Open AccessConcept Paper
Packet Key-Based End-to-End Security Management on a Blockchain Control Plane
Sensors 2019, 19(10), 2310; https://doi.org/10.3390/s19102310 (registering DOI) -
Abstract
The existing LTE mobile system uses the vertical model to handle the session-based security management. However, the goal of this paper is to propose a packet key-based security management scheme on the blockchain control plane to enhance the existing session key-based security scheme [...] Read more.
The existing LTE mobile system uses the vertical model to handle the session-based security management. However, the goal of this paper is to propose a packet key-based security management scheme on the blockchain control plane to enhance the existing session key-based security scheme and overcome the limitation that the existing vertical model, as well as the Software-Defined Networking (SDN) based horizontal model, confronts within solving end-to-end security management. The proposed blockchain-based security management (BSM) scheme enables each peer to easily obtain the necessary parameters required to manage the packet key-based security system. The important features of the BSM scheme include the renewal process, which enables the different packet data streams to use completely different security parameters for the security management. In addition, because even blind values cannot be exposed to the possible attackers, our BSM scheme guarantees very secure end-to-end data transfer against active attacks such as falsification of data and transactions. Finally, this paper compares the BSM scheme with the existing vertical model to prove the advantageous effects on latency. Full article
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Open AccessArticle
Evaluation of the Aging Effect on the Microstructure of Co-28Cr-6Mo-0.3C Alloy: Experimental Characterization and Computational Thermodynamics
Metals 2019, 9(5), 581; https://doi.org/10.3390/met9050581 (registering DOI) -
Abstract
In the current research, we studied the role of the solution treatment and aging on the microstructure of a Co–28Cr–5Mo–0.3C alloy. We used metallographic observations, scanning electron microscopy (SEM), and hardness measurements for the evaluations. We also made a comparison between the phase [...] Read more.
In the current research, we studied the role of the solution treatment and aging on the microstructure of a Co–28Cr–5Mo–0.3C alloy. We used metallographic observations, scanning electron microscopy (SEM), and hardness measurements for the evaluations. We also made a comparison between the phase equilibrium calculated with Thermo-Calc, using TCFE8 and TCNI8 thermodynamic databases and experimental findings. The experimental results showed that the transformation of the metastable FCC phase to the HCP phase during aging was extremely sensitive to the solution treatment prior to aging. The effect of the increase in the solution temperature and time was detectable through promotion of the martensitic transformation during quenching in which HCP1 (straight bands) and HCP2 (lamellar-type constitution) phases had developed. In contrast, a low solution temperature and time caused most of the primary carbides to remain in an undissolved condition in the matrix; therefore, during aging, no sign of the FCC to HCP1 (straight bands) phase transformation could be observed. However, we observed the formation of the HCP2 phase (lamellar-type constitution) at the grain boundaries. In addition, the X-ray diffraction pattern indicated that the sample solution treated at lower temperatures and shorter times had a stronger martensitic transformation during aging compared to the sample solution treated at higher temperatures and longer times. Hardness measurements confirmed the results. Thermodynamical calculations showed that an agreement existed between the experiments and calculations. We also discuss the results from the TCFE8 and TCNI8 databases. Full article
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Open AccessArticle
Sixteenth-Order Optimal Iterative Scheme Based on Inverse Interpolatory Rational Function for Nonlinear Equations
Symmetry 2019, 11(5), 691; https://doi.org/10.3390/sym11050691 (registering DOI) -
Abstract
The principal motivation of this paper is to propose a general scheme that is applicable to every existing multi-point optimal eighth-order method/family of methods to produce a further sixteenth-order scheme. By adopting our technique, we can extend all the existing optimal eighth-order schemes [...] Read more.
The principal motivation of this paper is to propose a general scheme that is applicable to every existing multi-point optimal eighth-order method/family of methods to produce a further sixteenth-order scheme. By adopting our technique, we can extend all the existing optimal eighth-order schemes whose first sub-step employs Newton’s method for sixteenth-order convergence. The developed technique has an optimal convergence order regarding classical Kung-Traub conjecture. In addition, we fully investigated the computational and theoretical properties along with a main theorem that demonstrates the convergence order and asymptotic error constant term. By using Mathematica-11 with its high-precision computability, we checked the efficiency of our methods and compared them with existing robust methods with same convergence order. Full article
Open AccessArticle
A Magnetic-Dependent Vibration Energy Harvester Based on the Tunable Point Defect in 2D Magneto-Elastic Phononic Crystals
Crystals 2019, 9(5), 261; https://doi.org/10.3390/cryst9050261 (registering DOI) -
Abstract
In this work, an innovative vibration energy harvester is designed by using the point defect effect of two-dimensional (2D) magneto-elastic phononic crystals (PCs) and the piezoelectric effect of piezoelectric material. A point defect is formed by removing the central Tenfenol-D rod to confine [...] Read more.
In this work, an innovative vibration energy harvester is designed by using the point defect effect of two-dimensional (2D) magneto-elastic phononic crystals (PCs) and the piezoelectric effect of piezoelectric material. A point defect is formed by removing the central Tenfenol-D rod to confine and enhance vibration energy into a spot, after which the vibration energy is electromechanically converted into electrical energy by attaching a piezoelectric patch into the area of the point defect. Numerical analysis of the point defect can be carried out by the finite element method in combination with the supercell technique. A 3D Zheng-Liu (Z-L) model which accurately describes the magneto-mechanical coupling constitutive behavior of magnetostrictive material is adopted to obtain variable band structures by applied magnetic field and pre-stress along the z direction. The piezoelectric material is utilized to predict the output voltage and power based on the capacity to convert vibration energy into electrical energy. For the proposed tunable vibration energy harvesting system, numerical results illuminate that band gaps (BGs) and defect bands of the in-plane mixed wave modes (XY modes) can be adjusted to a great extent by applied magnetic field and pre-stress, and thus a much larger range of vibration frequency and more broad-distributed energy can be obtained. The defect bands in the anti-plane wave mode (Z mode), however, have a slight change with applied magnetic field, which leads to a certain frequency range of energy harvesting. These results can provide guidance for the intelligent control of vibration insulation and the active design of continuous power supply for low power devices in engineering. Full article
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Open AccessArticle
Total, Added, and Free Sugar Consumption and Adherence to Guidelines in Switzerland: Results from the First National Nutrition Survey menuCH
Nutrients 2019, 11(5), 1117; https://doi.org/10.3390/nu11051117 (registering DOI) -
Abstract
The World Health Organization (WHO) recommends reducing free sugars to less than 10% of total energy intake (TEI) due to their potential implications in weight gain and dental caries. Our objectives were to (1) estimate the intake of total, added, and free sugars, [...] Read more.
The World Health Organization (WHO) recommends reducing free sugars to less than 10% of total energy intake (TEI) due to their potential implications in weight gain and dental caries. Our objectives were to (1) estimate the intake of total, added, and free sugars, (2) define the main sugar sources, and (3) evaluate the adherence to sugar guidelines. The first national nutrition survey 2014–2015 included non-institutional adults aged 18–75 years. Diet was assessed with two non-consecutive 24-hour dietary recalls in 2057 participants. Added and free sugar content was systematically estimated by two dietitians using available information from the manufacturer and/or standard recipe/composition. Usual daily intake distributions were modeled and weighted for sampling design, non-response, weekdays, and seasons. Total, added, and free sugar intake was respectively 107 g (±44), 53 g (±36), and 65 g (±40), representing 19%, 9%, and 11% of TEI. Sugar consumption was higher among younger adults and lower among people living in the Italian-speaking region. The three main food sources of free sugars were: (1) sweet products (47% of total free sugars), in particular sweet spreads (15%) and cakes/cookies (11%); (2) beverages (29%), mainly fruit and vegetable juices (13%), and sugar-sweetened beverages (12%, but 20% in younger adults); and (3) dairy products (9%), with yogurt accounting for 6%. Respectively, 44% of women and 45% of men had free sugar intake below 10% of TEI. Of people aged between 18–29, 30–64, and 65–75 years, 36%, 45%, and 53% had free sugar intake below 10% of TEI, respectively. The prevalence of Swiss people with free sugar intake that was <5% of the TEI was 8%. Adherence to the WHO recommendations guidelines was generally low in Switzerland, particularly among young adults, and in line with other high-income countries. Full article
Open AccessArticle
Effects of Intracerebroventricular and Intra-Arcuate Nucleus Injection of Ghrelin on Pain Behavioral Responses and Met-Enkephalin and β-Endorphin Concentrations in the Periaqueductal Gray Area in Rats
Int. J. Mol. Sci. 2019, 20(10), 2475; https://doi.org/10.3390/ijms20102475 (registering DOI) -
Abstract
Ghrelin is an endogenous ligand for orphan growth hormone secretagogue receptors. Ghrelin receptors have been found in central nervous system (CNS) areas responsible for pain modulation and transmission. This study investigated the effects of intracerebroventricular (ICV) and intra-arcuate nucleus (ARC) injection of ghrelin [...] Read more.
Ghrelin is an endogenous ligand for orphan growth hormone secretagogue receptors. Ghrelin receptors have been found in central nervous system (CNS) areas responsible for pain modulation and transmission. This study investigated the effects of intracerebroventricular (ICV) and intra-arcuate nucleus (ARC) injection of ghrelin on pain behavioral responses and levels of β-endorphin (β-EP) and met-enkephalin (MENK) in the periaqueductal gray area (PAG) during the formalin test in rats. Thirty-five male rats were studied in five groups. Ghrelin was injected into the left lateral ventricle (ICV, 5 µL) or into the ARC (1 µL). After 15 min, formalin (2.5%) was subcutaneously injected into the left hind paw. Behavioral nociceptive scores were recorded for 60 min. MENK and β-EP were collected by microdialysis in the PAG and determined by high-performance liquid chromatography (HPLC). ICV and ARC injection of ghrelin significantly reduced pain in all phases of the formalin test (p < 0.001). Dialysate concentrations of MENK and β-EP in the PAG increased in all the phases (p < 0.01). In conclusion, the present study shows that the ARC nucleus and the endogenous opioid system are involved in ghrelin-induced pain modulation. Full article
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Open AccessArticle
Proteomics Analysis of Urine to Examine Physical Effects of Warm Nano Mist Sauna Bathing
Healthcare 2019, 7(2), 71; https://doi.org/10.3390/healthcare7020071 (registering DOI) -
Abstract
Conventional sauna bathing may have some health benefits as it facilitates relaxing, detoxing and promoting metabolism. However, conventional sauna bathing at a high temperature may be harmful for the body by increasing the risk of heart failure. The nano-mist sauna has been developed [...] Read more.
Conventional sauna bathing may have some health benefits as it facilitates relaxing, detoxing and promoting metabolism. However, conventional sauna bathing at a high temperature may be harmful for the body by increasing the risk of heart failure. The nano-mist sauna has been developed to provide nano-size water particles at a lower temperature. Hence, nano-mist sauna bathing is expected to be useful for health without the risks that arise at high temperatures. In this study, we performed a comprehensive proteomics analysis of urine samples obtained from healthy volunteers before and after they had taken a sauna bath with nano-mist (n = 10) or with conventional mist (n = 10) daily for two weeks (4 groups). The average numbers of urine proteins identified by liquid chromatography-linked mass chromatography in each group varied from 678 to 753. Interestingly, the protein number was increased after sauna bathing both with nano-mist or with conventional mist. Quantitative analysis indicated that considerable numbers of proteins were obviously up-regulated, with more than two-folds in urine samples after the nano-mist sauna bathing. The KEGG pathway analysis showed significant stimulation of the lysosome pathway (p = 5.89E−6) after the nano-mist bathing, which may indicate the nano-mist sauna bathing promotes metabolism related to the lysosome pathway more efficiently than conventional mist sauna bathing and may provide more health benefits. Full article
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Open AccessFeature PaperArticle
Revisiting Calibration of the Solvency II Standard Formula for Mortality Risk: Does the Standard Stress Scenario Provide an Adequate Approximation of Value-at-Risk?
Risks 2019, 7(2), 58; https://doi.org/10.3390/risks7020058 (registering DOI) -
Abstract
The primary objective of this work is to analyze model based Value-at-Risk associated with mortality risk arising from issued term life assurance contracts and to compare the results with the capital requirements for mortality risk as determined using Solvency II Standard Formula. In [...] Read more.
The primary objective of this work is to analyze model based Value-at-Risk associated with mortality risk arising from issued term life assurance contracts and to compare the results with the capital requirements for mortality risk as determined using Solvency II Standard Formula. In particular, two approaches to calculate Value-at-Risk are analyzed: one-year VaR and run-off VaR. The calculations of Value-at-Risk are performed using stochastic mortality rates which are calibrated using the Lee-Carter model fitted using mortality data of selected European countries. Results indicate that, depending on the approach taken to calculate Value-at-Risk, the key factors driving its relative size are: sensitivity of technical provisions to the latest mortality experience, volatility of mortality rates in a country, policy term and benefit formula. Overall, we found that Solvency II Standard Formula on average delivers an adequate capital requirement, however, we also highlight particular situations where it could understate or overstate portfolio specific model based Value-at-Risk for mortality risk. Full article
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Open AccessFeature PaperArticle
Inhomogeneous Random Evolutions: Limit Theorems and Financial Applications
Mathematics 2019, 7(5), 447; https://doi.org/10.3390/math7050447 (registering DOI) -
Abstract
The paper is devoted to the inhomogeneous random evolutions (IHRE) and their applications in finance. We introduce and present some properties of IHRE. Then, we prove weak law of large numbers and central limit theorems for IHRE. Financial applications are given to illiquidity [...] Read more.
The paper is devoted to the inhomogeneous random evolutions (IHRE) and their applications in finance. We introduce and present some properties of IHRE. Then, we prove weak law of large numbers and central limit theorems for IHRE. Financial applications are given to illiquidity modeling using regime-switching time-inhomogeneous Levy price dynamics, to regime-switching Levy driven diffusion based price dynamics, and to a generalized version of the multi-asset model of price impact from distress selling, for which we retrieve and generalize their diffusion limit result for the price process. Full article
Open AccessReview
Ontogenetic and Pathogenetic Views on Somatic Chromosomal Mosaicism
Genes 2019, 10(5), 379; https://doi.org/10.3390/genes10050379 (registering DOI) -
Abstract
Intercellular karyotypic variability has been a focus of genetic research for more than 50 years. It has been repeatedly shown that chromosome heterogeneity manifesting as chromosomal mosaicism is associated with a variety of human diseases. Due to the ability of changing dynamically throughout [...] Read more.
Intercellular karyotypic variability has been a focus of genetic research for more than 50 years. It has been repeatedly shown that chromosome heterogeneity manifesting as chromosomal mosaicism is associated with a variety of human diseases. Due to the ability of changing dynamically throughout the ontogeny, chromosomal mosaicism may mediate genome/chromosome instability and intercellular diversity in health and disease in a bottleneck fashion. However, the ubiquity of negligibly small populations of cells with abnormal karyotypes results in difficulties of the interpretation and detection, which may be nonetheless solved by post-genomic cytogenomic technologies. In the post-genomic era, it has become possible to uncover molecular and cellular pathways to genome/chromosome instability (chromosomal mosaicism or heterogeneity) using advanced whole-genome scanning technologies and bioinformatic tools. Furthermore, the opportunities to determine the effect of chromosomal abnormalities on the cellular phenotype seem to be useful for uncovering the intrinsic consequences of chromosomal mosaicism. Accordingly, a post-genomic review of chromosomal mosaicism in the ontogenetic and pathogenetic contexts appears to be required. Here, we review chromosomal mosaicism in its widest sense and discuss further directions of cyto(post)genomic research dedicated to chromosomal heterogeneity. Full article
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