bluuebunny/crossref_metadata_2025 huggingface dataset:
The Sustainable Production of a Novel Laccase from Wheat Bran by Bordetella sp. JWO16: Toward a Total Environment
Authors: Unuofin John Onolame
Published: May 2021

Laccase is increasingly adopted in diverse industrial and environmental applications, due to its readily accessible requirements for efficient catalytic synthesis and biotransformation of chemicals. However, it is perceived that its industrial production might incur some unfavorable overhead, which leads to expensive market products, and the corresponding negative environmental feedback, due to the use of capital-intensive and precarious chemicals. To this end, this study was designed to evaluate the performance indicators of the valorization of wheat bran by a novel Jb1b laccase and its subsequent application in waste minimization and water management, on a laboratory scale. Optimal Jb1b laccase was produced in submerged fermentation medium containing wheat bran, an agroindustrial residue, through response surface methodology (RSM) algorithm, and was applied in dye decolorization and denim bioscouring, respectively. Results showed that the resultant enzyme manifested unique biochemical properties, such as enhanced tolerance at certain physicochemical conditions, with a residual activity of at least ca. 76%. Furthermore, phenomenally high concentrations of synthetic dyes (0.2% w v−1) were decolorized over 56 h, and a 6 h mediator-supported simultaneous denim bleaching and decolorization of wash effluent was observed. The sustainability of the production and application processes were inferred from the reusability of the fermentation sludge as a potential biofertilizer, with subsequent prospects for the biostimulation and bioaugmentation of contaminated soils, whereas the decolorized water could be adopted for other uses, amongst which horticulture and forestry are typical examples. These phenomena therefore authenticate the favorable environmental feedbacks and overhead realized in this present study.
Parental and Dentist Satisfaction with Primary Anterior Zirconia Crowns: A Case Series Analysis
Authors: Yanover Lawrence , Waggoner William , Kupietzky Ari , Moskovitz Moti , Tickotsky Nili
Published: May 2021

This retrospective cohort study evaluated overall parental satisfaction of zirconia crowns (ZC) placed on primary maxillary anterior teeth with that of two independent, blinded dentists. 131 ZC placed in 37 children, aged 24.8–62.2 months (mean = 42.8), who had at least one recall visit a minimum of 6 months after placement were rated (average = 13.3). Crown colour match, crown contour and crown durability were evaluated by parents and compared to photographic evaluations of two independent raters. Overall parental satisfaction was also evaluated. The overall retention rate was 99.7% and parental satisfaction was 100%. Colour match was rated excellent by 84% of parents and 36% of dental evaluators. Crown contour was rated excellent by 97% of parents and 55% of dental evaluators. The length of follow-up had no effect on colour match or crown contour. ZC comprises an aesthetic and durable option for restoring carious primary maxillary incisors and were well-accepted by parents. Parents were less critical than dental evaluators of crown appearance.
Highly Flexible Wind Turbine Blades Utilizing Corrugated Surface Hinges
Authors: Elsheikh Mogeeb Elrahman
Published: May 2021

An anthropomorphic wind turbine blade was the suggested design that had a flexure hinge at root, middle, and tip regions. The inter-distances of the flexure hinges follow the Fibonacci sequence and resembled the natural finger through binding. Therefore, the present study designs various corrugated flexure hinges. NACA0012 is chosen as the basic airfoil for designing the corrugated flexure hinges with different geometrical profiles and leading edges. The designs are based on morphing technology and the main geometrical parameters of the corrugation, the pitch distance along the span and the height, are inspired by tubercles of the whale flippers. The study uses the finite element method to define the significant strength characteristics of each design flap-wise, edge-wise, torsional stiffness, and buckling resistance in order to assign the best fit corrugation profile for each region of the blade.
Results from a Theory-Guided Survey to Support Breast Cancer Trial Participation: Barriers, Enablers, and What to Do about them
Authors: Brehaut Jamie C. , Carroll Kelly , Gordon Jenn , Presseau Justin , Richards Dawn P. , Fergusson Dean A. , Graham Ian D. , Marlin Susan
Published: May 2021

Background: Ensuring adequate, informed, and timely participation in clinical trials is a multifactorial problem. We have previously developed a systematic, tailorable survey development approach that is informed by theory, can identify barriers and enablers to participation, and can suggest recruitment strategies to address these issues. In this study, we surveyed subscribers to the Canadian Breast Cancer Network (CBCN) in order to identify a comprehensive list of theory-informed barriers and enablers relevant to participation in a hypothetical breast cancer trial. Methods: We developed and conducted an online survey of breast cancer patients informed by the Theoretical Domains Framework and designed to determine previous experience with clinical trials, knowledge about clinical trials, and importance of a comprehensive list of barriers and enablers to trial participation. Participants were contacted by email or through social media. Results: From 2451 subscribers of the CBCN, we received 244 responses and 210 completed surveys (244/2451 or 9.9% participation, 210/244 or 86.1% completion). A total of 38% of respondents indicated experience in trial participation, but 83% indicated confidence in their knowledge about clinical trials. Those who had previously participated in clinical trials were more confident in their knowledge (χ2= 6.77, p = 0.009) and answered more knowledge questions (t = −3.90 p = 0.000). Endorsed barriers and enablers to participation included 39 factors across 12 of 14 domains relevant to behaviour change. Our approach identifies barriers that might be meaningfully addressed by careful knowledge provision (‘If I would learn more about my condition’; ‘If I find the trial documents hard to understand’), those that may require other theory-informed approaches to address (‘my feelings about the quality of my drug plan’; ‘my worry over unknown side effects’), and those that may require tailored approaches depending on participant differences such as previous experience in trials (‘If there were patient-friendly decision-making tools to help you make your participation decision’). Discussion: This work demonstrates that a comprehensive, theory-guided survey of barriers and enablers to participation in breast cancer clinical trials is feasible, can lead to detailed knowledge about the issues related to participation in specific trials, and most importantly, can lead to insights about evidence-based ways to better support patient participation.
Incidence and Characteristics of Kidney Stones in Patients on Ketogenic Diet: A Systematic Review and Meta-Analysis
Authors: Acharya Prakrati , Acharya Chirag , Thongprayoon Charat , Hansrivijit Panupong , Kanduri Swetha R. , Kovvuru Karthik , Medaura Juan , Vaitla Pradeep , Garcia Anton Desiree F. , Mekraksakit Poemlarp , Pattharanitima Pattharawin , Bathini Tarun , Cheungpasitporn Wisit
Published: May 2021

Very-low-carbohydrate diets or ketogenic diets are frequently used for weight loss in adults and as a therapy for epilepsy in children. The incidence and characteristics of kidney stones in patients on ketogenic diets are not well studied. Methods: A systematic literature search was performed, using MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from the databases’ inception through April 2020. Observational studies or clinical trials that provide data on the incidence and/or types of kidney stones in patients on ketogenic diets were included. We applied a random-effects model to estimate the incidence of kidney stones. Results: A total of 36 studies with 2795 patients on ketogenic diets were enrolled. The estimated pooled incidence of kidney stones was 5.9% (95% CI, 4.6–7.6%, I2 = 47%) in patients on ketogenic diets at a mean follow-up time of 3.7 +/− 2.9 years. Subgroup analyses demonstrated the estimated pooled incidence of kidney stones of 5.8% (95% CI, 4.4–7.5%, I2 = 49%) in children and 7.9% (95% CI, 2.8–20.1%, I2 = 29%) in adults, respectively. Within reported studies, 48.7% (95% CI, 33.2–64.6%) of kidney stones were uric stones, 36.5% (95% CI, 10.6–73.6%) were calcium-based (CaOx/CaP) stones, and 27.8% (95% CI, 12.1–51.9%) were mixed uric acid and calcium-based stones, respectively. Conclusions: The estimated incidence of kidney stones in patients on ketogenic diets is 5.9%. Its incidence is approximately 5.8% in children and 7.9% in adults. Uric acid stones are the most prevalent kidney stones in patients on ketogenic diets followed by calcium-based stones. These findings may impact the prevention and clinical management of kidney stones in patients on ketogenic diets.
Ordinal Pattern Dependence in the Context of Long-Range Dependence
Authors: Nüßgen Ines , Schnurr Alexander
Published: May 2021

Ordinal pattern dependence is a multivariate dependence measure based on the co-movement of two time series. In strong connection to ordinal time series analysis, the ordinal information is taken into account to derive robust results on the dependence between the two processes. This article deals with ordinal pattern dependence for a long-range dependent time series including mixed cases of short- and long-range dependence. We investigate the limit distributions for estimators of ordinal pattern dependence. In doing so, we point out the differences that arise for the underlying time series having different dependence structures. Depending on these assumptions, central and non-central limit theorems are proven. The limit distributions for the latter ones can be included in the class of multivariate Rosenblatt processes. Finally, a simulation study is provided to illustrate our theoretical findings.
What Factors in Nepal Account for the Rural–Urban Discrepancy in Human Capital? Evidence from Household Survey Data
Authors: Devkota Satis , Ghimire Shankar , Upadhyay Mukti
Published: May 2021

We analyze the factors that determine human capital formation in the rural and urban sectors of Nepal and decompose the intersectoral difference into variables underlying supply and demand for human capital. In particular, we examine the role of access to primary and secondary schools as well as the socioeconomic, demographic, and geographic characteristics of households. Our results are based on Nepal Living Standards Survey data for 2004 and 2011. We find that access to schooling has a significant impact on the level of human capital, especially in rural areas. Our Blinder–Oaxaca decomposition attributes a large portion of the rural–urban gap to socioeconomic and demographic variables. Yet, the results reinforce our claim that an improvement in schooling access and road infrastructure is also necessary, particularly in the vast rural sector of Nepal, if human capital development is to provide a greater contribution to national welfare.
Heuristics Hindering the Development of Understanding of Molecular Structures in University Level Chemistry Education: The Lewis Structure as an Example
Authors: Karonen Maarit , Murtonen Mari , Södervik Ilona , Manninen Marianna , Salomäki Mikko
Published: May 2021

Understanding chemical models can be challenging for many university students studying chemistry. This study analysed students’ understanding of molecular structures using the Lewis structure as a model, and examined what hinders their understanding. We conducted pre- and post-tests to analyse students’ conceptions and changes in them. The measures contained multiple-choice questions and drawing tasks testing their understanding of concepts, such as polarity, geometry, charge or formal charge and expanded octet. The pre-test revealed a lack of knowledge and several misconceptions in students’ prior knowledge. For example, the concept of polarity was well-known, but the combination of polarity and geometry appeared to be difficult. For some students, the representation of molecules was intuitive and lacking a systematic approach. Certain students used mnemonics and draw ball-and-stick models connected to surficial representations. After the chemistry courses, the conceptions and drawings had generally changed, and the level of the students’ knowledge increased markedly. Although, fewer ball-and-stick models were drawn in the post-test, some students still used them. The main result was that students who drew ball-and-stick models in the pre-test were less capable of drawing the correct Lewis structures with electrons in the post-test. In addition, heuristics seem to hinder learning and some concepts, such as resonance, remained difficult. This is probably due to the fact that understanding molecular structures requires systemic understanding, where several matters must be understood at the same time. Our study highlights that the understanding of molecular structures requires conceptual change related to several sub-concepts.
A Huffman-Based Joint Compression and Encryption Scheme for Secure Data Storage Using Physical Unclonable Functions
Authors: Liu Yong , Li Bing , Zhang Yan , Zhao Xia
Published: May 2021

With the developments of Internet of Things (IoT) and cloud-computing technologies, cloud servers need storage of a huge volume of IoT data with high throughput and robust security. Joint Compression and Encryption (JCAE) scheme based on Huffman algorithm has been regarded as a promising technology to enhance the data storage method. Existing JCAE schemes still have the following limitations: (1) The keys in the JCAE would be cracked by physical and cloning attacks; (2) The rebuilding of Huffman tree reduces the operational efficiency; (3) The compression ratio should be further improved. In this paper, a Huffman-based JCAE scheme using Physical Unclonable Functions (PUFs) is proposed. It provides physically secure keys with PUFs, efficient Huffman tree mutation without rebuilding, and practical compression ratio by combining the Lempel-Ziv and Welch (LZW) algorithm. The performance of the instanced PUFs and the derived keys was evaluated. Moreover, our scheme was demonstrated in a file protection system with the average throughput of 473Mbps and the average compression ratio of 0.5586. Finally, the security analysis shows that our scheme resists physical and cloning attacks as well as several classic attacks, thus improving the security level of existing data protection methods.
GPR B-Scan Image Denoising via Multi-Scale Convolutional Autoencoder with Data Augmentation
Authors: Luo Jiabin , Lei Wentai , Hou Feifei , Wang Chenghao , Ren Qiang , Zhang Shuo , Luo Shiguang , Wang Yiwei , Xu Long
Published: May 2021

Ground-penetrating radar (GPR), as a non-invasive instrument, has been widely used in civil engineering. In GPR B-scan images, there may exist random noise due to the influence of the environment and equipment hardware, which complicates the interpretability of the useful information. Many methods have been proposed to eliminate or suppress the random noise. However, the existing methods have an unsatisfactory denoising effect when the image is severely contaminated by random noise. This paper proposes a multi-scale convolutional autoencoder (MCAE) to denoise GPR data. At the same time, to solve the problem of training dataset insufficiency, we designed the data augmentation strategy, Wasserstein generative adversarial network (WGAN), to increase the training dataset of MCAE. Experimental results conducted on both simulated, generated, and field datasets demonstrated that the proposed scheme has promising performance for image denoising. In terms of three indexes: the peak signal-to-noise ratio (PSNR), the time cost, and the structural similarity index (SSIM), the proposed scheme can achieve better performance of random noise suppression compared with the state-of-the-art competing methods (e.g., CAE, BM3D, WNNM).
A Novel Decomposition Model for Visual Rail Surface Inspection
Authors: Zhang Ziwen , Liang Mangui , Liu Zhiyu
Published: May 2021

Rail surface inspection plays a pivotal role in large-scale railway construction and development. However, accurately identifying possible defects involving a large variety of visual appearances and their dynamic illuminations remains challenging. In this paper, we fully explore and use the essential attributes of our defect structure data and the inherent temporal and spatial characteristics of the track to establish a general theoretical framework for practical applications. As such, our framework can overcome the bottleneck associated with machine vision inspection technology in complex rail environments. In particular, we consider a differential regular term for background rather than a traditional low-rank constraint to ensure that the model can tolerate dynamic background changes without losing sensitivity when detecting defects. To better capture the compactness and completeness of a defect, we introduce a tree-shaped hierarchical structure of sparse induction norms to encode the spatial structure of the defect area. The proposed model is evaluated with respect to two newly released Type-I/II rail surfaces discrete defects (RSDD) data sets and a practical rail line. Qualitative and quantitative evaluations show that the decomposition model can handle the dynamics of the track surface well and that the model can be used for structural detection of the defect area.
Large-Eddy Simulation Analyses of Heated Urban Canyon Facades
Authors: Cintolesi Carlo , Barbano Francesco , Di Sabatino Silvana
Published: May 2021

Thermal convective flows are common phenomena in real urban canyons and strongly affect the mechanisms of pollutant removal from the canyon. The present contribution aims at investigating the complex interaction between inertial and thermal forces within the canyon, including the impacts on turbulent features and pollutant removal mechanisms. Large-eddy simulations reproduce infinitely long square canyons having isothermal and differently heated facades. A scalar source on the street mimics the pollutant released by traffic. The presence of heated facades triggers convective flows which generate an interaction region around the canyon-ambient interface, characterised by highly energetic turbulent fluxes and an increase of momentum and mass exchange. The presence of this region of high mixing facilitates the pollutant removal across the interface and decreases the urban canopy drag. The heating-up of upwind facade determines favourable convection that strengthens the primary internal vortex and decreases the pollutant concentration of the whole canyon by 49% compare to the isothermal case. The heating-up of the downwind facade produces adverse convection counteracting the wind-induced motion. Consequently, the primary vortex is less energetic and confined in the upper-canyon area, while a region of almost zero velocity and high pollution concentration (40% more than the isothermal case) appears at the pedestrian level. Finally, numerical analyses allow a definition of a local Richardson number based on in-canyon quantities only and a new formulation is proposed to characterise the thermo-dynamics regimes.
MRAS-Based Switching Linear Feedback Strategy for Sensorless Speed Control of Induction Motor Drives
Authors: Fnaiech Mohamed Amine , Guzinski Jaroslaw , Trabelsi Mohamed , Kouzou Abdellah , Benbouzid Mohamed , Luksza Krzysztof
Published: May 2021

This paper presents a newly designed switching linear feedback structure of sliding mode control (SLF-SMC) plugged with an model reference adaptive system (MRAS) based sensorless field-oriented control (SFOC) for induction motor (IM). Indeed, the performance of the MRAS depends mainly on the operating point and the parametric variation of the IM. Hence, the sliding mode control (SMC) could be considered a good control alternative due to its easy implementation and robustness. Simulation and experimentation results are presented to show the superiority of the proposed SLF-SMC technique in comparison with the classical PI controller under different speed ranges and inertia conditions.
Utility Scale Ground Mounted Photovoltaic Plants with Gable Structure and Inverter Oversizing for Land-Use Optimization
Authors: Cossu Silvestro , Baccoli Roberto , Ghiani Emilio
Published: May 2021

The paper proposes an effective layout for ground-mounted photovoltaic systems with a gable structure and inverter oversizing, which allows an optimized use of the land and, at the same time, guarantees a valuable return on investment. A case study is presented to show the technical, economic, and environmental advantages compared with conventional “fixed-tilt” and “sun-tracking” ground-mounted photovoltaic installations. The main advantage of this solution is that it maximizes the energy produced per unit of land area used; but, also considering the economic metrics, the net present value of the proposed PV arrangement solution results in a greater annual volume of energy produced and therefore of net revenues and cash flows, and greater than the compared conventional solution with modules exposed in an optimal fixed position or which make use of sun-tracking systems.
Hydraulic Interactions between Injection Events Using Multiple Injection Strategies and a Solenoid Diesel Injector
Authors: Martínez-Martínez Simón , de la Garza Oscar A. , García-Yera Miguel , Martínez-Carrillo Ricardo , Sánchez-Cruz Fausto A.
Published: May 2021

An experimental study was performed to explore the influence of dwell time on the hydraulic interactions between injection events using pilot injection strategy, split injection strategy, post injection strategy and a solenoid diesel injector. To do so, a sweep of dwell time from 0.55 up to 2 ms using all multiple injection strategies and levels of rail pressure, of 80, 100 and 120 MPa, and single level of back pressure, of 5 MPa, was performed. The hydraulic interactions between injection events were characterized through the second injection hydraulic delay and second injection mass in an injection discharge curve indicator equipped with all the components required for its operation and control. In order to define the operating conditions of the multiple injection strategies, to ensure the same injected fuel mass in all cases, the characteristic curves of injection rate for the solenoid diesel injector studied were obtained. The second injection hydraulic delay increases with dwell time values in the range of 0.55–0.9 ms for all multiple injection strategies and levels of rail pressure tested. Conversely, the second injection hydraulic delay decreases with dwell time values higher than 0.9 ms. Moreover, the second hydraulic delay depends mainly on the dwell time and not on the injected fuel mass during the first injection event. The second injection mass increases with dwell values less than 0.6 ms. By contrast, the second injection mass is not significantly affected by that of the first injection at a dwell time higher than 0.6 ms.
Numerical Study on Performance Enhancement of the Air-Cooled Battery Thermal Management System by Adding Parallel Plates
Authors: Wang Meiwei , Hung Tzu-Chen , Xi Huan
Published: May 2021

Air-cooled battery thermal management system (BTMS) technology is commonly used to control the temperature distribution of the battery pack in an electric vehicle. In this study, parallel plates are introduced to improve the cooling efficiency of the BTMS, which can change the airflow distribution of the battery pack. Firstly, the effect of the number of parallel plates on the cooling performance of the BTMS is investigated; within the acceptable range of power consumption loss, the model with two parallel plates shows the best cooling efficiency, and Tmax and ΔTmax are reduced by 2.42 and 3.46 K, respectively. Then, the influences of the length and height of parallel plates are studied; the optimal values for length and height are 1.5 and 30 mm, respectively. Finally, the conclusions drawn above are used to design three optimization schemes for the model with four parallel plates; the cooling efficiency of the battery pack can be improved efficiently, which illustrates the feasibility of the above conclusions. Compared to the original model, Tmax and ΔTmax are, respectively, reduced by 3.37 K (6.17%) and 5.5 K (71.9%) after optimization.
Reliability Assessment of a Multi-State HVDC System by Combining Markov and Matrix-Based Methods
Authors: Benato Roberto , Chiarelli Antonio , Sessa Sebastian Dambone
Published: May 2021

The purpose of this paper is to highlight that, in order to assess the availability of different HVDC cable transmission systems, a more detailed characterization of the cable management significantly affects the availability estimation since the cable represents one of the most critical elements of such systems. The analyzed case study consists of a multi-terminal direct current system based on both line commutated converter and voltage source converter technologies in different configurations, whose availability is computed for different transmitted power capacities. For these analyses, the matrix-based reliability estimation method is exploited together with the Monte Carlo approach and the Markov state space one. This paper shows how reliability analysis requires a deep knowledge of the real installation conditions. The impact of these conditions on the reliability evaluation and the involved benefits are also presented.
Rotational Piezoelectric Energy Harvesting: A Comprehensive Review on Excitation Elements, Designs, and Performances
Authors: Chilabi Haider Jaafar , Salleh Hanim , Al-Ashtari Waleed , Supeni E. E. , Abdullah Luqman Chuah , As’arry Azizan B. , Rezali Khairil Anas Md , Azwan Mohammad Khairul
Published: May 2021

Rotational Piezoelectric Energy Harvesting (RPZTEH) is widely used due to mechanical rotational input power availability in industrial and natural environments. This paper reviews the recent studies and research in RPZTEH based on its excitation elements and design and their influence on performance. It presents different groups for comparison according to their mechanical inputs and applications, such as fluid (air or water) movement, human motion, rotational vehicle tires, and other rotational operational principal including gears. The work emphasises the discussion of different types of excitations elements, such as mass weight, magnetic force, gravity force, centrifugal force, gears teeth, and impact force, to show their effect on enhancing output power. It revealed that a small compact design with the use of magnetic, gravity, and centrifugal forces as excitation elements and a fixed piezoelectric to avoid a slip ring had a good influence on output power optimisation. One of the interesting designs that future works should focus on is using gear for frequency up-conversion to enhance output power density and keep the design simple and compact.
Prospects of Using Hydrocarbon Deposits from the Autochthonous Miocene Formation (Eastern Carpathian Foredeep, Poland) for Geothermal Purposes
Authors: Chmielowska Anna , Sowiżdżał Anna , Tomaszewska Barbara
Published: May 2021

There are many oil and gas fields around the world where the vast number of wells have been abandoned or suspended, mainly due to the depletion of reserves. Those abandoned oil and gas wells (AOGWs) are often located in areas with a prospective geothermal potential and might be retrofitted to a geothermal system without high-cost drilling. In Poland, there are thousands of wells, either operating, abandoned or negative, that might be used for different geothermal applications. Thus, the aim of this paper is not only to review geothermal and petroleum facts about the Eastern Carpathian Foredeep, but also to find out the areas, geological structures or just AOGWs, which are the most prospective in case of geothermal utilization. Due to the inseparability of geological settings with both oil and gas, as well as geothermal conditionings, firstly, the geological background of the analyzed region was performed, considering mainly the autochthonous Miocene formation. Then, geothermal and petroleum detailed characteristics were made. In the case of geothermal parameters, such as formation’s thickness, temperatures, water-bearing horizons, wells’ capacities, mineralization and others were extensively examined. Considering oil and gas settings, insights into reservoir rocks, hydrocarbon traps and migration paths issues were created. Then, for evaluating geothermal parameters for specific hydrocarbon reservoirs, their depths were established based on publicly available wells data. Thereafter, the average temperatures for selected reservoirs were set. As the effect, it turned out that most of the deposits have average temperatures of 40/50 °C, nonetheless, there are a few characterized by higher (even around 80 °C) temperatures at reasonable depths.
Design of a Medium Voltage Generator with DC-Cascade for High Power Wind Energy Conversion Systems
Authors: Steffen Jonas , Lengsfeld Sebastian , Jung Marco , Ponick Bernd , Herranz Gracia Mercedes , Spagnolo Aristide , Klöpzig Markus , Schleicher Klaus , Schäfer Klaus
Published: May 2021

This paper shows a new concept to generate medium voltage (MV) in wind power application to avoid an additional transformer. Therefore, the generator must be redesigned with additional constraints and a new topology for the power rectifier system by using multiple low voltage (LV) power rectifiers connected in series and parallel to increase the DC output voltage. The combination of parallel and series connection of rectifiers is further introduced as DC-cascade. With the resulting DC-cascade, medium output voltage is achieved with low voltage rectifiers and without a bulky transformer. This approach to form a DC-cascade reduces the effort required to achieve medium DC voltage with a simple rectifier system. In this context, a suitable DC-cascade control was presented and verified with a laboratory test setup. A gearless synchronous generator, which is highly segmented so that each segment can be connected to its own power rectifier, is investigated. Due to the mixed AC and DC voltage given by the DC-cascade structure, it becomes more demanding to the design of the generator insulation, which influences the copper fill factor and the design of the cooling system. A design strategy for the overall generator design is carried out considering the new boundary conditions.
Monolithic Perovskite-Carrier Selective Contact Silicon Tandem Solar Cells Using Molybdenum Oxide as a Hole Selective Layer
Authors: Song Hoyoung , Lee Changhyun , Hyun Jiyeon , Lee Sang-Won , Choi Dongjin , Pyun Dowon , Nam Jiyeon , Jeong Seok-Hyun , Kim Jiryang , Bae Soohyun , Lee Hyunju , Kang Yoonmook , Kim Donghwan , Lee Hae-Seok
Published: May 2021

Monolithic perovskite–silicon tandem solar cells with MoOx hole selective contact silicon bottom solar cells show a power conversion efficiency of 8%. A thin 15 nm-thick MoOx contact to n-type Si was used instead of a standard p+ emitter to collect holes and the SiOx/n+ poly-Si structure was deposited on the other side of the device for direct tunneling of electrons and this silicon bottom cell structure shows ~15% of power conversion efficiency. With this bottom carrier selective silicon cell, tin oxide, and subsequent perovskite structure were deposited to fabricate monolithic tandem solar cells. Monolithic tandem structure without ITO interlayer was also compared to confirm the role of MoOx in tandem cells and this tandem structure shows the power conversion efficiency of 3.3%. This research has confirmed that the MoOx layer simultaneously acts as a passivation layer and a hole collecting layer in this tandem structure.
Local Energy Trading in Future Distribution Systems
Authors: Honarmand Mohammad Esmaeil , Hosseinnezhad Vahid , Hayes Barry , Siano Pierluigi
Published: May 2021

Today, the pace of development of decentralized transactive management systems has increased significantly due to growing renewable energy source technologies and communication infrastructure at the distribution system level. Such bilateral energy transactions have changed the structure of electricity markets and led to the emergence of a local energy market in electricity distribution. While examining this change of attitude, this paper analyzes the effects of local market formation on the performance and performance of distribution companies. Accordingly, the technical requirements in the three areas of operation, network control, and ICT in the new workspace are thoroughly examined. The hardware requirements will be presented in two parts for the end-user and the distribution systems. Then, the proposed local distribution market framework will be introduced, and finally, the conclusion will be presented.
Ginsenoside CK Inhibits Hypoxia-Induced Epithelial–Mesenchymal Transformation through the HIF-1α/NF-κB Feedback Pathway in Hepatocellular Carcinoma
Authors: Zhang Jingjing , Ma Xiaoxuan , Fan Daidi
Published: May 2021

Hepatocellular carcinoma (HCC) is a kind of malignant tumor with high morbidity and mortality rates worldwide. Epithelial–mesenchymal transformation (EMT) is crucial for HCC progression and prognosis. Characteristics of the tumor microenvironment, such as hypoxia, and excessive activation of the NF-κB signaling pathway have been identified as the key inducers of EMT in HCC. In our study, we verified the crosstalk between HIF-1α signaling and NF-κB pathway and their effects on EMT in HCC cells. The results show that CoCl2-induced hypoxia could promote IκB phosphorylation to activate NF-κB signaling and vice versa. Moreover, we found that ginsenoside CK, a metabolite of protopanaxadiol saponins, could inhibit the proliferation and colony formation of different HCC cell lines. Furthermore, ginsenoside CK could impair the metastatic potential of HCC cell lines under hypoxic conditions. Mechanistically, ginsenoside CK suppressed HIF-1α/NF-κB signaling and expression level of EMT-related proteins and cytokines in hypoxia-induced or TNFα-stimulated HCC cell lines. An in vivo study revealed that the oral delivery of ginsenoside CK could inhibit the growth of xenograft tumors and block HIF-1α and NF-κB signaling as well as EMT marker expression. Our study suggests that ginsenoside CK is a potential therapy for HCC patients that functions by targeting the HIF-1α/NF-κB crosstalk.
Explaining Chinese Consumers’ Green Food Purchase Intentions during the COVID-19 Pandemic: An Extended Theory of Planned Behaviour
Authors: Qi Xin , Ploeger Angelika
Published: May 2021

The outbreak of the COVID-19 pandemic has strongly influenced consumers’ habits and behaviours, creating a more sustainable and healthier era of consumption. Hence, there is a potential for further expanding the green food sector in China. The theory of planned behaviour (TPB) is one widely used framework to explain consumers’ food choices. Considering consumers’ internal norms, their perceptions of green food attributes, and the shifting consumer behaviour, our study has extended the TPB framework (E-TPB) by adding constructs of moral attitude, health consciousness, and the impact of COVID-19 (IOC). The results of structural equation modelling among 360 functional samples revealed that the E-TPB model has a superior explanatory and predictive power, compared with the original TPB model regarding Chinese consumers’ green food buying intentions in the current and post-pandemic periods. The path analysis demonstrated that attitude, perceived behavioural control, moral attitude, health consciousness, and IOC have significant positive effects on green food purchase intentions. However, the association between subjective norm and purchase intention varies within the TPB and E-TPB models, which showed a non-significant impact in E-TPB. These findings can generate more suitable managerial implications to promote green food consumption in China during the current and post-pandemic periods.
Absence of Genotype/Phenotype Correlations Requires Molecular Diagnostic to Ascertain Stargardt and Stargardt-Like Swiss Patients
Authors: Buhler Virginie M.M. , Berger Lieselotte , Schaller André , Zinkernagel Martin S. , Wolf Sebastian , Escher Pascal
Published: May 2021

We genetically characterized 22 Swiss patients who had been diagnosed with Stargardt disease after clinical examination. We identified in 11 patients (50%) pathogenic bi-allelic ABCA4 variants, c.1760+2T>C and c.4496T>C being novel. The dominantly inherited pathogenic ELOVL4 c.810C>G p.(Tyr270*) and PRPH2-c.422A>G p.(Tyr141Cys) variants were identified in eight (36%) and three patients (14%), respectively. All patients harboring the ELOVL4 c.810C>G p.(Tyr270*) variant originated from the same small Swiss area, identifying a founder mutation. In the ABCA4 and ELOVL4 cohorts, the clinical phenotypes of “flecks”, “atrophy”, and “bull’s eye like” were observed by fundus examination. In the small number of patients harboring the pathogenic PRPH2 variant, we could observe both “flecks” and “atrophy” clinical phenotypes. The onset of disease, progression of visual acuity and clinical symptoms, inheritance patterns, fundus autofluorescence, and optical coherence tomography did not allow discrimination between the genetically heterogeneous Stargardt patients. The genetic heterogeneity observed in the relatively small Swiss population should prompt systematic genetic testing of clinically diagnosed Stargardt patients. The resulting molecular diagnostic is required to prevent potentially harmful vitamin A supplementation, to provide genetic counseling with respect to inheritance, and to schedule appropriate follow-up visits in the presence of increased risk of choroidal neovascularization.
Socioeconomic Determinants of Smoking in the Kingdom of Saudi Arabia
Authors: Qattan Ameerah M.N. , Boachie Micheal Kofi , Immurana Mustapha , Al-Hanawi Mohammed Khaled
Published: May 2021

Tobacco consumption, or smoking, is a major cause of preventable morbidity and mortality worldwide, including in the Kingdom of Saudi Arabia (KSA). In order to reduce the consumption of tobacco products, it is necessary to understand the factors that drive it. However, little is known about the socioeconomic determinants of tobacco smoking in the KSA. This study, therefore, investigates the socioeconomic factors that influence tobacco smoking in the KSA. Using a national health survey, the study employs logistic and negative binomial regressions to examine the socioeconomic factors associated with smoking. Moreover, the inequality concentration indices (CIs) are used to assess inequalities in smoking. The results reveal that the smoking prevalence is 14.09% of the 8813 respondents considered in this study. The prevalence of smoking is higher among men (25.34%) than among women (1.91%). On the determinants of smoking, the logistic regression results show that higher income is associated with lower likelihood of smoking. Other factors significantly associated with current smoking status are marital status, gender, age, and region of residence. Similarly, gender, age and region of residence are significantly associated with smoking intensity. As regards the inequality analysis, at the national level, the results show that smoking is concentrated among those with higher socioeconomic status (income: CI = 0.071, p < 0.01; education: CI = 0.095, p < 0.01), but with significant regional variations. By gender disaggregation, the results also show that the income-based CIs are positive for both males and females, but statistically insignificant. Education-based CI is positive for males and significant (CI = 0.057, p < 0.05), while it is negative and insignificant for females during the study period. The findings call for targeted tobacco control measures focusing on those with higher socioeconomic status, as well as factors such as age, gender, marital status and region of residence.
Mobile Phone Use and Cognitive Impairment among Elderly Chinese: A National Cross-Sectional Survey Study
Authors: Qi Shige , Sun Yuying , Yin Peng , Zhang Han , Wang Zhihui
Published: May 2021

The study aimed to investigate the relationship between mobile phone use and cognitive impairment using the data of the Prevention and Intervention on Neurodegenerative Disease for Elderly in China (PINDEC) survey. A total of 21,732 participants aged 60 years and above in China were recruited using a stratified, multi-stage cluster sampling method, providing information on demographics, lifestyle and health-related characteristics, mobile phone use, and cognitive impairment through face-to-face interviews by trained staff according to a standard protocol. All estimates of rates were weighted by sex, age, and living area (rural or urban) in the elderly Chinese population. The rate of mobile phone usage was 65.5% (14.3% for smartphone use). The prevalence of cognitive impairment in non-users of mobile phone, dumbphone users, and smartphone users were 17.8%, 5.0%, and 1.4%, respectively. The odds of having cognitive impairment in users of dumbphone and smartphone were lower than non-users after adjusting for demographics, lifestyle, and health-related factors (adjusted odds ratio (AOR), 0.39, 95% CI 0.35 to 0.45; p < 0.001; AOR, 0.16, 95% CI 0.11 to 0.25; p < 0.001, respectively). Smartphone use in Chinese elderly people was quite low. A strong correlation was found between mobile phone use and better cognitive function; yet longitudinal studies are warranted to explore the causal relationship. Future design of mobile phone-based interventions should consider the feasibility among those in need.
Effectiveness of App-Based Yoga of Immortals (YOI) Intervention for Insomnia in Asian Population during Pandemic Restrictions
Authors: Tunuguntla Renuka , Tunuguntla Hari Siva Gurunadha Rao , Kathuria Himanshu , Verma Sadhna
Published: May 2021

The coronavirus disease 2019 (COVID-19) pandemic created significant psychological challenges worldwide, including stress, emotional distress, and insomnia. In addition, social distancing, travel restrictions, and spread of disease have resulted in unique challenges, creating barriers to healthcare access. Compared to the rate prior to the COVID-19 pandemic, a significant increase in clinical insomnia rates have been reported. With well-known limitations of currently established treatments (e.g., cognitive behavioral therapy-insomnia (CBT-I), pharmacotherapy), there is a need to explore other effective and safe treatment modalities to treat insomnia, especially those that can be used remotely. The purpose of this study is to assess the effectiveness of app-based intervention to treat insomnia in the current era of the COVID-19 pandemic (using the Yoga of Immortals (YOI) app). This prospective cohort study was approved by the Institutional Review Board. All participants in this study were asked to complete an online survey including demographic data and validated Insomnia Severity Index (ISI) at baseline (15 May 2020), 4 weeks, and 8 weeks after starting the YOI intervention. Survey data was exported using Microsoft Excel. Statistical analysis was done using the GraphPad Prism 8. YOI intervention significantly improved the mean ISI scores in all categories of insomnia (severe, moderate, and subthreshold) at each follow-up (p ≤ 0.0001). The improvement was significant among all age groups and in both genders. In our study, YOI was a novel and effective intervention for improving insomnia symptoms and may be a new addition to the armamentarium of insomnia management. Being app-based, this has potential wider applicability, especially during the current COVID-19 pandemic.
The Relationship of School Start Times, Sleep Duration and Mental Health among a Representative Sample of High School Students in Colorado, 2019
Authors: Neuroth Lucas M. , Ma Ming , Brooks-Russell Ashley , Zhu Motao
Published: May 2021

This cross-sectional study utilized responses from 46,537 students enrolled in grades 9 through 12 in 166 high schools across the state of Colorado via the 2019 Healthy Kids Colorado Survey to: (1) quantify the association between high school start times and student sleep duration and (2) investigate the associations between school start times and student mental health. Descriptive and bivariate analyses were used to investigate associations between school start times and self-reported demographic, sleep, and mental health factors. Survey-weighted multivariate regression modeling was used to investigate associations between school start times, sleep duration, and mental health. Schools with late start times (≥8:30 a.m.) saw 32.2% (95% Confidence Interval: 29.5–35.0) of students sleeping 8 h or more relative to 23.2% (22.0–24.4) in schools with very early start times (<8:00 a.m.). For every 15 min later school start time, students’ sleep duration was 4.6 (3.4–5.9) min longer. Students attending schools with very early start times had 1.10 (0.95–1.27) times the odds of attempting suicide compared to those attending schools with later start times, while students at schools with early starts (8:00–8:29 a.m.) were associated with 1.11 (0.98–1.27) times the odds. Schools with later school start times had a statistically significantly higher proportion of students sleeping 8+ hours. Schools with start times before 8:30 a.m. had 10–11% higher odds of students attempting suicide compared to schools with late start times, though these differences were not statistically significant. Student mental health should continue to be investigated when assessing the potential impacts of delayed school start times.
Pregnancy Outcome, Antibodies, and Placental Pathology in SARS-CoV-2 Infection during Early Pregnancy
Authors: Jang Won-Kyu , Lee Su-Yeon , Park Sunggyun , Ryoo Nam Hee , Hwang Ilseon , Park Ji Min , Bae Jin-Gon
Published: May 2021

There are reports that pregnant women infected with SARS-CoV-2 not only have increased morbidity but also increased complications and evidence of maternal and fetal vascular malperfusion on placental pathology. This was a retrospective study of pregnant women diagnosed with SARS-CoV-2 infection after March 2020. The results of reverse transcription polymerase chain reaction testing and IgM and IgG antibody testing of the amniotic fluid, cord blood, placenta, and maternal blood were confirmed at delivery. Placentas were evaluated histopathologically. The study included seven pregnant women diagnosed with SARS-CoV-2 infection during pregnancy at a mean gestational age of 14.5 weeks. Out of the seven women, five were infected during the first trimester. The mean gestational age at delivery was 38.4 weeks. The reverse transcription polymerase chain reaction results for maternal plasma, cord blood, placenta, and amniotic fluid were negative and IgG antibodies were detected in maternal plasma and cord blood. On placental pathology, maternal vascular malperfusion was found in only one case, fetal vascular malperfusion in four cases, and inflammatory changes were found in two cases. Pregnancy outcomes for women diagnosed with SARS-CoV-2 infection during early pregnancy are positive and it is likely that maternal antibodies are passed to the fetus, which results in a period of immunity.